KR100879694B1 - Refrigerating device - Google Patents

Abstract

It installs an internal heat exchanger (23) capable of controlling the temperature of the refrigerant flowing into the expander (12), and by adjusting the temperature of the refrigerant when the operating conditions are changed, by controlling the cost or flow rate of the refrigerant, and the compressor (11) and The flow rate imbalance of the expander 12 is eliminated. In the cooling operation in which the circulation amount of the refrigerant is increased as compared with the heating operation, the cooling performance of the internal heat exchanger 23 is higher than in the heating operation, so that a part of the refrigerant does not bypass the inflator 12 even if a part of the refrigerant is bypassed. Allow coolant flow to increase. This prevents the COP of the refrigerating device from being lowered.

COP, bypass, heat transfer performance, cost, refrigerant density, mass flow rate, balance, compressor, expander

Description

Freezer {REFRIGERATING DEVICE}

The present invention relates to a refrigerating device having a refrigerant circuit for performing a vapor compression refrigeration cycle, and more particularly to a refrigerating device in which an expander constituting an expansion mechanism of the refrigerant circuit is mechanically connected to a compressor.

Background Art Conventionally, a refrigerating device that circulates a refrigerant in a refrigerant circuit as a closed circuit to perform a refrigeration cycle is known, and is widely used as an air conditioner. As this type of refrigerating device, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2001-107881), it is known that the high pressure of the refrigerating cycle is set higher than the critical pressure of the refrigerant. This refrigeration apparatus is provided with an expander comprised of a scroll fluid machine as an expansion mechanism of a refrigerant. The expander and the compressor are mechanically connected to each other by a shaft, and the power obtained from the expander is used to drive the compressor to improve the COP (resulting coefficient).

In the refrigerating device of Patent Literature 1, the mass flow rate of the refrigerant passing through the expander and the mass flow rate of the refrigerant passing through the compressor are always equal. This is because the refrigerant circuit is a closed circuit. On the other hand, the refrigerant density at the inlet of the expander or the compressor changes depending on the operating conditions of the refrigerating device. On the other hand, in the refrigerating device of Patent Document 1, since the expander and the compressor are connected to each other, it is not possible to change the displacement volume ratio of the expander and the compressor. Therefore, there is a problem that it is impossible to continue the operation of the refrigerating apparatus stably when the operating conditions change.

For example, if this type of refrigeration apparatus is configured to be capable of heating and cooling operation, the amount of refrigerant circulation changes during the cooling operation and the heating operation, resulting in an unbalanced flow rate between the compressor and the expander. Specifically, if the refrigerating cycle is designed so that the flow rate of the expander and the compressor is balanced during the heating operation, the refrigerant circulation amount increases during the cooling operation in which the suction gas of the compressor becomes a high temperature. Exclusion amount) becomes insufficient.

The above points will be explained in other words.

In the refrigeration apparatus of Patent Literature 1, the power recovery efficiency of the compressor is lowered because of the fact that the refrigerant circuit is a closed circuit and the lighting of the inflator and the compressor rotates at the same rotation speed, thereby achieving a high COP refrigeration cycle. Becomes difficult.

In the refrigerant circuit which is a closed circuit, the mass flow rate Me of the refrigerant passing through the expander and the mass flow rate Mc of the refrigerant passing through the compressor are equal. Where Me = Ve × de (Ve: volume circulating amount of the refrigerant passing through the expander, de: inflow refrigerant density of the expander), Mc = Vc × dc (Vc: volume circulating amount of the refrigerant passing through the compressor, dc: suction refrigerant of the compressor Density) holds true. The volume circulation amounts Vc and Ve are determined by the cylinder volume of each fluid machine x the rotation speed of each fluid machine.

Since the mass flow rate Me of the expander and the mass flow rate Mc of the compressor are equivalent, the relationship Ve / Vc = de / dc is established from the above equation. Here, Ve / Vc is a fixed value determined by the designed cylinder volume since the rotation speeds of the expander and the compressor are the same. Therefore, in this refrigeration apparatus, by making the density ratio de / dc constant, the refrigerant mass flow rates Me and Mc of the expander and the compressor can be balanced.

By the way, when using this kind of refrigerating apparatus, etc., it may be difficult to keep the said density ratio de / dc constant according to the use condition. Specifically, for example, in an air conditioner which switches between the cooling operation (cooling operation) and the heating operation (heating operation), the cooling operation has a higher refrigerant evaporation pressure at the use-side heat exchanger (evaporator) than the heating operation. , The suction refrigerant density (dc) of the compressor is increased. As a result, with respect to the mass flow rate Mc of the refrigerant passing through the compressor, the mass flow rate Me of the refrigerant passing through the expander becomes small, and the refrigerant mass flow rates Me and Mc of the expander and the compressor are unbalanced.

As for this problem, as disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 2001-116371), a countermeasure has been proposed in which a bypass pipe bypassing the expander is provided in the refrigerant circuit. That is, when the amount of exclusion of the expander is insufficient, a portion of the refrigerant after the heat dissipation is introduced into the bypass pipe, thereby limiting the amount of refrigerant sent to the expander, so that the refrigeration cycle can be continued stably. In other words, when the mass flow rate Me of the refrigerant passing through the expander is small relative to the mass flow rate Mc of the refrigerant passing through the compressor, a portion of the refrigerant after heat dissipation is introduced into the bypass pipe to bypass the expander. In this case, balance the mass flow rate as a whole of the refrigerant circuit.

[Initiation of invention]

[Problem to Solve Invention]

However, in the apparatus of Patent Literature 2, when a part of the refrigerant is introduced into the bypass pipe when the operating conditions are changed, the power obtained from the expander decreases, resulting in a drop in the coefficient of performance (COP) of the refrigerating device.

The present invention was devised in view of the above problems, and an object thereof is to solve the imbalance between the flow rate of the compressor and the inflator when the operating conditions change (the mass flow rate of the refrigerant passing through the compressor and the mass flow rate of the refrigerant passing through the expander). And the COP of the refrigerating device is also prevented from being lowered.

[Means for solving the problem]

In the first to eighth inventions, when the operating conditions are changed, by controlling the temperature of the refrigerant flowing into the expander, the cost of the refrigerant is adjusted, thereby eliminating the unbalance in flow rate between the compressor and the expander, and reducing the COP of the refrigerating device. It is to suppress what happens.

Specifically, the first invention includes a refrigerant circuit (10) for connecting a compressor (11), a heat source side heat exchanger (21), an expansion mechanism (12), and a use side heat exchanger (22) to perform a vapor compression refrigeration cycle. In addition, the expansion mechanism 12 is composed of an inflator 12 for generating power by the expansion of the refrigerant, the premise that the expander 12 and the compressor 11 is a refrigeration device mechanically connected.

The refrigerating device is characterized in that the temperature control means 23 capable of controlling the temperature of the refrigerant flowing into the expander 12 is configured.

In this first invention, the cost of the refrigerant can be adjusted by adjusting the temperature of the refrigerant flowing into the expander 12 with the temperature adjusting means. Specifically, as the coolant is lowered in temperature, the cost is small and the flow rate of the coolant to the expander is increased. As the coolant is heated to high temperature, the cost is increased and the coolant flow rate to the expander is reduced. Therefore, by adjusting the temperature of the refrigerant flowing into the expander 12, it becomes possible to balance the flow rates of the compressor 11 and the expander 12 even if the operating conditions are changed. Moreover, in this invention, since the refrigerant | coolant flowing into the expander 12 does not need to be bypassed, the power obtained by the expander 12 also does not fall.

2nd invention is the refrigeration apparatus of 1st invention WHEREIN: The refrigerant | coolant circuit 10 is a heating operation by which the refrigerant | coolant which flows through the utilization side heat exchanger 22 dissipates, and the refrigerant | coolant which flows through this utilization side heat exchanger 22 endotherm Cooling operation is configured to be possible, the temperature control means 23 is characterized in that the cooling performance of the coolant flowing into the expander 12 is increased in the cooling operation than in the heating operation.

In this second invention, since the cooling performance of the temperature regulating means 23 is higher in the cooling operation than in the heating operation, the refrigerating cycle is designed so that the flow rates of the expander 12 and the compressor 11 are balanced during the heating operation. In one case, even if the refrigerant circulation amount increases during the cooling operation, the flow rate of the refrigerant flowing into the expander 12 can be increased. This can prevent the flow rate of the expander 12 from running short during the cooling operation. Therefore, it is possible to balance the flow rates of the expander 12 and the compressor 11 during the cooling operation and the heating operation, and since the bypass power is not required, the recovery power of the expander 12 does not decrease.

3rd invention is the refrigeration apparatus of 2nd invention WHEREIN: The temperature control means 23 uses the heat exchanger by which the refrigerant | coolant after passing the heat source side heat exchanger 21 which becomes a radiator at the time of cooling operation becomes an evaporator. It is characterized by consisting of an internal heat exchanger (23) which is cooled by heat exchange with a refrigerant before or after passing (22).

In the third invention, the refrigerant after passing through the heat source side heat exchanger 21 serving as the radiator during the cooling operation passes the internal side heat exchange with the refrigerant before or after passing through the utilization side heat exchanger 22 serving as the evaporator. It is cooled by heat exchange in group 23. As a result, since the cost or flow rate of the refrigerant flowing into the expander 12 is adjusted, the flow rates of the compressor 11 and the expander 12 can be balanced in the heating operation and the cooling operation.

In the fourth invention, in the refrigerating device of the third invention, the internal heat exchanger (23) is a refrigerant flow path through which the refrigerant before or after passing through the use-side heat exchanger (22) that becomes the evaporator during the cooling operation ( The heat transfer performance of 25) is higher than the heat transfer performance of the refrigerant passage 24 through which the refrigerant flows after passing through the heat source side heat exchanger 21 serving as the radiator, and during the heating operation, the heat source side heat exchanger that becomes the evaporator. The heat transfer performance of the refrigerant passage 25 through which the refrigerant after passing through the use-side heat exchanger 22 that becomes the radiator passes through the heat transfer performance of the refrigerant passage 24 through which the refrigerant flows before or after the passage 21 passes. It is characterized in that it is configured to be lower.

In this fourth invention, the heat transfer rate of the refrigerant after passing through the radiator is higher than the heat transfer rate of the low pressure refrigerant before or after passing through the evaporator. Refrigerant flow path through which the refrigerant flows through the heat source-side heat exchanger 21, which passes through the heat source-side heat exchanger 21, through which the refrigerant flows through which the refrigerant flows before or after passing through the utilization-side heat exchanger 22 serving as the evaporator. The heat transfer performance of the refrigerant passage 24 through which the refrigerant flows before or after passing through the heat source-side heat exchanger 21, which becomes the evaporator, becomes higher than the heat transfer performance of 24, and during the heating operation, Since the refrigerant after passing through the use-side heat exchanger 22 is lower than the heat transfer performance of the refrigerant flow passage 25 through which the refrigerant flows, the amount of heat exchange during the cooling operation becomes larger than the amount of heat exchange during the heating operation. Therefore, during the cooling operation, since the refrigerant flowing into the expander 12 is cooled more than during the heating operation, the flow rate of the refrigerant flowing into the expander 12 during the cooling operation is increased, so that the compressor 11 and the expander 12 The flow rate can be balanced in the heating operation and the cooling operation.

In the refrigerating device of the fourth invention, the fifth invention is characterized in that a refrigerant flows through the internal heat exchanger (23) before or after passing through the use-side heat exchanger (22), which becomes an evaporator during the cooling operation, and during the heating operation. The heat transfer fin 26 is provided in the coolant flow path 25 through which the coolant after passing through the use-side heat exchanger 22 serving as the radiator flows.

In this fifth invention, the heat exchange fins 26 are provided in the predetermined refrigerant path 25 of the internal heat exchanger 23, so that the amount of heat exchange in the internal heat exchanger 23 during the cooling operation is larger than during the heating operation. . In this way, the cost or flow rate of the refrigerant flowing into the expander 12 can be adjusted, so that the flow rates of the compressor 11 and the expander 12 can be balanced during the heating operation and the cooling operation.

In the sixth invention, in the refrigerating device of the third invention, the internal heat exchanger (23) is a refrigerant before or after passing through the use-side heat exchanger (22) that becomes an evaporator and a radiator during the cooling operation. The refrigerant after passing through the heat source side heat exchanger 21 flows in the opposite direction to each other, and at the time of heating operation, the refrigerant before or after passing through the heat source side heat exchanger 21 serving as the evaporator and the use side serving as the radiator. It is characterized in that the refrigerant after passing through the heat exchanger 22 is configured to flow in the same direction to each other.

In the sixth invention, the heat exchange efficiency at the time of cooling operation in the internal heat exchanger 23 is higher than the heat exchange rate at the time of heating operation. Therefore, since the internal heat exchanger 23 passes through the expander 12 and the cooling performance of the refrigerant is higher in the cooling operation than in the heating operation, the flow rate of the compressor 11 and the expander 12 is increased during the cooling operation and the heating operation. It becomes possible to balance when driving.

7th invention is the refrigeration apparatus of 3rd invention WHEREIN: The internal heat exchanger 23 is comprised by the double tube heat exchanger in which the inner side flow path 24 and the outer side flow path 25 are arrange | positioned adjacently.

In this seventh invention, during the cooling operation, a double tube heat exchanger is used to pass through the refrigerant before or after passing through the use-side heat exchanger 22 serving as the evaporator and the heat source side heat exchanger 21 serving as the radiator. By exchanging the refrigerant thereafter, the cost or flow rate of the refrigerant flowing into the expander 12 can be adjusted to balance the flow rates of the compressor 11 and the expander 12 during the cooling operation and the heating operation. .

In the eighth invention, in the refrigerating device of the third invention, the internal heat exchanger (23) includes an inner flow passage (24) and a first outer flow passage (25A) disposed adjacent to the outside of the inner flow passage (24). It is characterized by consisting of a three-layer plate heat exchanger having a second outer flow passage 25B.

In the eighth aspect of the invention, the refrigerant before or after passing through the use-side heat exchanger 22 serving as the evaporator and the heat source side heat exchanger 21 serving as the radiator are used by the three-layer plate heat exchanger during the cooling operation. By heat exchanging the refrigerant after passing, the cost or flow rate of the refrigerant flowing into the expander 12 can be adjusted to balance the flow rate of the compressor 11 and the expander 12 during the cooling operation and the heating operation. have.

In the ninth to seventeenth inventions, the refrigerant flowing into the expander 12 is cooled only during the cooling operation, and the temperature adjusting means 23 is stopped during the heating operation.

Specifically, the ninth invention includes a refrigerant circuit (10) for connecting a compressor (11), a heat source side heat exchanger (21), an expansion mechanism (12), and a use side heat exchanger (22) to perform a vapor compression refrigeration cycle. The refrigerant circuit 10 is configured to enable a cooling operation in which the refrigerant flowing through the use side heat exchanger 22 absorbs heat and a heating operation in which the refrigerant flowing through the use side heat exchanger 22 radiates heat. The expansion mechanism 12 is composed of an expander 12 that generates power by expansion of a refrigerant, and assumes a refrigerating device in which the expander 12 and the compressor 11 are mechanically connected.

And the refrigerating device is provided with a temperature control means 23 capable of controlling the temperature of the high-pressure refrigerant flowing into the expander 12, the temperature control means 23 to cool the high-pressure refrigerant only during the cooling operation In the heating operation, the cooling of the high-pressure refrigerant is characterized in that configured to stop.

In the ninth aspect of the present invention, the high-pressure refrigerant flowing into the expander 12 is cooled only during the cooling operation and not cooled during the heating operation, so that the inflow refrigerant density de of the expander 12 can be increased during the cooling operation. have. Therefore, even when the mass flow rate Mc of the refrigerant passing through the compressor 11 becomes larger than during the heating operation during the cooling operation, the refrigerant sucked into the expander 12 by following this is cooled, thereby passing through the expander 12. The mass flow rate Me of the refrigerant can be increased to balance the refrigerant mass flow rates Mc and Me of both. Moreover, in this invention, since the refrigerant | coolant flowing into the expander 12 does not need to be bypassed, the power obtained by the expander 12 also does not fall.

In a tenth aspect of the invention, in the refrigerating device of the ninth invention, the temperature adjusting means (23) is constituted by an internal heat exchanger (23) in which the high pressure refrigerant is heat exchanged with the low pressure refrigerant during cooling operation. .

In the tenth aspect of the present invention, the high pressure refrigerant is exchanged with the low pressure refrigerant by the internal heat exchanger 23 in the cooling operation to be cooled. As a result, the suction temperature of the compressor 11 is increased to lower the refrigerant density, and the inlet temperature of the expander 12 is lowered to increase the refrigerant density. Thereby, during the cooling operation, the mass flow rate Me of the refrigerant passing through the expander 12 can be increased, and the mass flow rate Mc of the refrigerant passing through the compressor 11 can be balanced.

11th invention is the refrigerant | coolant of 10th invention WHEREIN: The internal heat exchanger 23 has the 1st flow path 27 and the 2nd flow path 28, and the refrigerant which flows through this 1st flow path 27 is carried out. And the refrigerant flowing through the second flow path 28 are configured to be heat exchangeable, and the internal heat exchanger 23 is configured to allow the high pressure refrigerant to flow through the first flow path 27 during the cooling operation, while the second flow path 28 It is characterized in that the low pressure refrigerant is circulated, the high-pressure refrigerant is circulated in both flow paths (24, 25) during the heating operation.

In the eleventh invention, since the high pressure refrigerant flows through the two flow paths 24 and 25 of the internal heat exchanger 23 during the heating operation, the high pressure refrigerant flows into the expander 12 without changing the temperature. On the other hand, during the cooling operation, the high pressure refrigerant flowing through the first flow passage 27 in the internal heat exchanger 23 is cooled by heat exchange with the low pressure refrigerant flowing through the second flow passage 28. Thereby, during the cooling operation, the mass flow rate Me of the refrigerant passing through the expander 12 can be increased to balance the mass flow rate Mc of the refrigerant passing through the compressor 11.

In the twelfth invention, in the refrigerating device of the tenth invention, the internal heat exchanger (23) has a first flow passage (27) and a second flow passage (28), and a refrigerant flowing through the first flow passage (27); The refrigerant flowing through the second flow passage 28 is configured to be heat exchangeable, and the internal heat exchanger 23 is configured to allow the high pressure refrigerant to flow through the first flow passage 27 during the cooling operation and to open the second flow passage 28. The low pressure refrigerant is configured to flow, and in the heating operation, the high pressure refrigerant is characterized by including a bypass passage 45 for bypassing the internal heat exchanger 23.

In this twelfth invention, since the high pressure refrigerant bypasses the internal heat exchanger 23 during the heating operation, the high pressure refrigerant flows into the expander 12 without changing the temperature. On the other hand, during the cooling operation, the high pressure refrigerant flowing through the first flow passage 27 in the internal heat exchanger 23 is cooled by heat exchange with the low pressure refrigerant flowing through the second flow passage 28. Thereby, the mass flow rate Me of the refrigerant passing through the expander 12 can be increased during the cooling operation, and the mass flow rate Mc of the refrigerant passing through the compressor 11 can be balanced.

In the thirteenth invention, in the refrigerating device of the tenth invention, the internal heat exchanger (23) has a first flow passage (27) and a second flow passage (28), and a refrigerant flowing through the first flow passage (27). And the refrigerant flowing through the second flow path 28 are configured to be heat exchangeable, and the internal heat exchanger 23 is configured to allow the high pressure refrigerant to flow through the first flow path 27 during the cooling operation, while the second flow path 28 It is characterized in that it is configured such that the low pressure refrigerant flows, the bypass passage 46 for bypassing the internal heat exchanger 23 during the heating operation.

In the thirteenth invention, since the low pressure refrigerant bypasses the internal heat exchanger 23 during the heating operation, the high pressure refrigerant flows into the expander 12 without changing the temperature. On the other hand, during the cooling operation, the high pressure refrigerant flowing through the first flow passage 27 in the internal heat exchanger 23 is cooled by heat exchange with the low pressure refrigerant flowing through the second flow passage 28. Thereby, the mass flow rate Me of the refrigerant passing through the expander 12 can be increased during the cooling operation, and the mass flow rate Mc of the refrigerant passing through the compressor 11 can be balanced.

14th invention is the refrigerating apparatus of 10th invention WHEREIN: The internal heat exchanger 23 passes the high pressure refrigerant | coolant after passing the heat source side heat exchanger 21 at the time of cooling operation, and passes through the utilization side heat exchanger 22. Characterized in that configured to cool by heat exchange with the low-pressure refrigerant before.

In this fourteenth invention, the high pressure refrigerant after passing through the heat source side heat exchanger (21) during the cooling operation is cooled by heat exchange with the low pressure refrigerant before passing through the use side heat exchanger (22). Flows into the expander 12 in a raised state. Thereby, the mass flow rate Me of the refrigerant passing through the expander 12 can be increased during the cooling operation, and the mass flow rate Mc of the refrigerant passing through the compressor 11 can be balanced.

In the fifteenth invention, in the refrigerating device of the tenth invention, the internal heat exchanger (23) passes the high pressure refrigerant after passing through the heat source side heat exchanger (21) through the use side heat exchanger (22) during the cooling operation. It is characterized in that it is configured to cool by heat exchange with the low pressure refrigerant after.

In this fifteenth invention, the high pressure refrigerant after passing through the heat source-side heat exchanger (21) during the cooling operation is cooled by heat exchange with the low pressure refrigerant after passing through the use-side heat exchanger (22). Flows into the expander 12 in a raised state. Thereby, the mass flow rate Me of the refrigerant passing through the expander 12 can be increased during the cooling operation, and the mass flow rate Mc of the refrigerant passing through the compressor 11 can be balanced.

In the sixteenth invention, in the refrigerating device of the tenth invention, the internal heat exchanger (23) is configured such that the high pressure refrigerant and the low pressure refrigerant flow in the opposite direction to each other during the cooling operation.

In the sixteenth aspect of the present invention, the high pressure refrigerant and the low pressure refrigerant flow in the opposite direction to the internal heat exchanger 23 during the cooling operation, whereby the high pressure refrigerant is efficiently cooled. Therefore, in the same manner as described above, the mass flow rate Me of the refrigerant passing through the expander 12 during the cooling operation can be increased to balance the mass flow rate Mc of the refrigerant passing through the compressor 11.

In the seventeenth invention, in the refrigerating device of the ninth invention, the refrigerant in the refrigerant circuit (10) is carbon dioxide.

In the seventeenth aspect of the present invention, by using carbon dioxide as the refrigerant, it is possible to increase the high and low differential pressure of the refrigerating cycle as compared with other refrigerants, so that the expansion power of the refrigerant obtained by the expander 12 can be increased.

The eighteenth to twenty-ninth inventions make it possible to use a gas-liquid separator having an internal heat exchanger for heat exchanging a refrigerant expanded in the expander and a refrigerant sucked into the expander.

Specifically, the eighteenth invention includes a refrigerant circuit (10) for connecting a compressor (11), a heat source side heat exchanger (21), an expander (12), and a use side heat exchanger (22) to perform a refrigeration cycle. The compressor 11 and the expander 12 are mechanically connected to the refrigerating device for recovering the expansion power of the expander 12. The refrigerating device is provided with a gas-liquid separator 51 that temporarily separates the refrigerant expanded in the expander 12 into a liquid refrigerant and a gas refrigerant, and the gas-liquid separator 51 includes the gas-liquid separator 51. And an internal heat exchanger 50 for exchanging heat between the liquid refrigerant separated from the refrigerant and the refrigerant sucked into the expander 12.

In the eighteenth invention, a gas-liquid separator (51) is provided in the refrigerant circuit (10). The gas-liquid separator 51 separates the refrigerant in the gas-liquid two-phase state after being expanded by the expander 12 into a gas refrigerant and a liquid refrigerant. The gas-liquid separator 51 is provided with an internal heat exchanger 50. The internal heat exchanger 50 heat exchanges the refrigerant sucked into the expander 12 and the liquid refrigerant stored in the gas-liquid separator 51.

Since the refrigerant sucked into the expander 12 is higher than the liquid refrigerant after being expanded in the expander 12, the refrigerant sucked into the expander 12 is cooled in the internal heat exchanger 50. As a result, the suction refrigerant density de of the expander 12 can be increased. Thus, for example, even when the mass flow rate Mc of the refrigerant passing through the compressor 11 increases during the cooling operation, the refrigerant sucked into the expander 12 by following this is cooled, thereby passing through the expander 12. The mass flow rate Me of the refrigerant can be increased to balance the refrigerant mass flow rates Mc and Me of both.

19th invention is the refrigeration apparatus of 18th invention WHEREIN: The heat exchange amount adjustment mechanism 60 which changes the refrigerant heat exchange amount in the internal heat exchange part 50 according to an operating condition is provided. Here, the "heat exchange amount adjusting mechanism" means that the heat exchange amount can be finely adjusted according to the operating conditions, and the two-stage adjustment (ON / OFF control) of whether the heat exchange amount is substantially zero or a predetermined value is possible. It means to include.

In the nineteenth invention, the heat exchange amount of the refrigerant sucked into the expander 12 and the liquid refrigerant separated by the gas-liquid separator 51 is changed by the heat exchange amount adjusting mechanism 60 in accordance with the operating conditions. Thus, when the refrigerant mass flow rate Me of the expander 12 is larger than the refrigerant mass flow rate Mc of the compressor 11 due to the change in the operating conditions, the amount of heat exchange in the internal heat exchange unit 50 is adjusted. The refrigerant mass flow rate Me of the expander 12 and the refrigerant mass flow rate Mc of the compressor 11 can be made equivalent.

In the twentieth invention, in the refrigerating device of the nineteenth invention, the gas-liquid separator (51) is adjacent to the liquid reservoir (52) in which the separated liquid refrigerant is stored, and the liquid reservoir (52). And a heat transfer tube 50 through which the refrigerant sucked into 12 passes. The heat exchange tube 50 includes an internal heat exchanger configured to heat exchange liquid refrigerant in the liquid reservoir 52 with the refrigerant in the heat transfer tube 50. To construct.

In the twentieth invention, the gas-liquid separator 51 is provided with a heat transfer tube 50 as an internal heat exchanger. This heat exchanger tube 50 is arrange | positioned so that the liquid storage part 52 may be adjacent. Thus, the refrigerant sucked into the expander 12 is cooled by the liquid refrigerant stored in the outer surface of the heat transfer tube 50 when the heat transfer tube 50 flows. Therefore, the suction refrigerant density de of the expander 12 can be reliably increased.

A twenty-first aspect of the present invention provides a refrigerating device of the twentieth aspect, comprising: refrigerant switching mechanisms (31, 33) for switching the refrigerant circulation direction of the refrigerant circuit (10) to switch between the cooling operation and the heating operation. 60 heat exchanges the refrigerant in the internal heat exchanger 50 only during the cooling operation.

In the twenty-first aspect of the present invention, the refrigerant switching mechanisms (31, 33) are configured in the refrigerant circuit (10). The refrigerant switching mechanisms 31 and 33 switch to the cooling operation in which the use-side heat exchanger 22 is an evaporator and the heating operation in which the use-side heat exchanger 22 is a radiator by switching the circulation direction of the refrigerant.

Here, the heat exchange amount adjusting mechanism 60 heat-exchanges the refrigerant in the internal heat exchange part 50 only during the cooling operation. As a result, during the cooling operation in which the refrigerant mass flow rate Me of the expander 12 tends to be smaller than the refrigerant mass flow rate Mc of the compressor 11, the intake refrigerant density de of the expander 12 is increased to thereby increase the inflator 12. The refrigerant mass flow rate Me of (12) and the refrigerant mass flow rate Mc of the compressor 11 can be made equivalent.

On the other hand, during the heating operation, by designing the cylinder volume ratio of the expander 12 and the compressor 11 in accordance with the density ratio of the suction refrigerant density de of the expander 12 and the suction refrigerant density dc of the compressor 11. The refrigerant mass flow rate Me of the expander 12 and the refrigerant mass flow rate Mc of the compressor 11 can be made equivalent. Therefore, it is not necessary to perform refrigerant heat exchange in the internal heat exchange part 50 by the heat exchange amount adjustment mechanism 60.

In the twenty-second aspect of the present invention, in the refrigerating device of the twenty-first aspect, the heat exchange amount adjusting mechanism (60) includes a bypass tube (57) for bypassing the heat transfer pipe (50) and suction of refrigerant into the expander (12), and the heat transfer pipe (50). It is comprised by the 1st electric valve 36 which adjusts the refrigerant flow volume which distributes (circle), and the 2nd electric valve 37 which adjusts the refrigerant flow volume of the said bypass pipe 57. As shown in FIG.

In the twenty-second aspect of the present invention, the amount of refrigerant heat exchange in the heat transfer pipe (50) is adjusted by adjusting the opening degrees of the first and second electric valves (36, 37). Specifically, for example, when the first electric valve 36 is fully open and the second electric valve 37 is fully closed, the flow rate of the refrigerant flowing through the heat transfer pipe 50 is maximized, and the heat transfer pipe 50 is The amount of refrigerant heat exchange is also adjusted to the maximum. On the other hand, for example, when the first electric valve 36 is completely closed and the second electric valve 37 is unfolded, the flow rate of the refrigerant flowing through the heat transfer pipe 50 becomes substantially zero, and the heat of the refrigerant in the heat transfer pipe 50 is reduced. The exchange amount is also zero. By adjusting the opening degree of the 1st, 2nd electric valve 36, 37 as a predetermined opening degree as mentioned above, the heat exchange amount in the heat exchanger tube 50 can be adjusted from zero to a maximum value. Therefore, since the heat exchange of the refrigerant according to the operating conditions can be performed, the refrigerant mass flow rate Me of the expander 12 and the refrigerant mass flow rate Mc of the compressor 11 can be made equivalent.

In the twenty-third aspect of the present invention, in the refrigerating device of the twenty-first aspect, the heat exchange amount adjusting mechanism (60) is constituted by a cross switching valve (32).

In the twenty-third aspect of the present invention, the refrigerant flow is changed by switching of the four-way switching valve 32 as the heat exchange amount adjusting mechanism 60. Thus, for example, the crossover switching valve 32 is switched to send the refrigerant to the heat transfer tube 50 during the cooling operation, and the crossover switching valve 32 is switched so as not to send the refrigerant to the heat transfer tube 50 during the heating operation. By doing so, the refrigerant mass flow rate Me of the expander 12 and the refrigerant mass flow rate Mc of the compressor 11 can be equalized in both operations.

24th invention is the refrigerating apparatus of 21st invention WHEREIN: The bypass pipe | tube 57 which the heat exchange amount adjustment mechanism 60 bypasses the heat exchanger tube 50, and sucks in refrigerant | coolant to the expander 12, and the heat exchanger tube 50 The first electromagnetic opening and closing valve 34 to allow or prohibit the refrigerant flow of the (), and the second electromagnetic opening and closing valve 35 to allow or prohibit the refrigerant flow of the bypass pipe (57).

In the twenty-fourth invention, the flow of the refrigerant in the heat transfer pipe (50) is changed by opening and closing the first and second electromagnetic opening and closing valves (34, 35). Specifically, for example, during the cooling operation, the first electromagnetic open / close valve 34 is opened and the second electromagnetic open / close valve 35 is closed, thereby circulating the refrigerant through the heat transfer pipe 50, thereby transmitting the heat transfer pipe 50. ) Can be a refrigerant heat exchange. On the other hand, for example, during the heating operation, the first electromagnetic open / close valve 34 is closed and the second electromagnetic open / close valve 35 is opened to distribute the refrigerant to the bypass pipe 57, while the heat transfer pipe ( 50) can prevent the refrigerant from flowing. That is, in this state, it is possible to prevent the refrigerant from being heat exchanged in the heat transfer pipe 50. Therefore, during both operations, the refrigerant mass flow rate Me of the expander 12 and the refrigerant mass flow rate Mc of the compressor 11 can be made equivalent.

In the twenty-fifth aspect of the present invention, in the refrigerating device of the twenty-first aspect, the heat exchange amount adjusting mechanism (60) is configured by a combination of a pipe and a check valve (81, 82, 83, 84).

In the twenty-fifth aspect of the present invention, a predetermined pipe path and check valves 81, 82, 83, and 84 are configured as the heat exchange amount adjusting mechanism 60. Thus, for example, by installing the check valves (81, 82, 83, 84) and the pipe path so that the refrigerant flows through the heat transfer tube 50 during the cooling operation, and does not send the refrigerant to the heat transfer tube (50) during the heating operation. In both operations, the refrigerant mass flow rate Me of the expander 12 and the refrigerant mass flow rate Mc of the compressor 11 can be equalized.

In the refrigerating device of the eighteenth invention, in the refrigerating device of the eighteenth invention, the refrigerant circuit (10) includes a first injection pipe (55) for sending gas refrigerant of the gas-liquid separator (51) to the suction side of the compressor (11), and the first It is provided with a gas control valve 38 for adjusting the refrigerant flow rate of the injection pipe (55).

In the twenty-sixth aspect of the present invention, the gas refrigerant separated by the gas-liquid separator (51) can be sent to the suction side of the compressor (11) via the first injection pipe (55). Therefore, if necessary, so-called gas injection can be performed, and the gas injection amount can be adjusted by changing the opening degree of the gas control valve 38.

27th invention is the refrigeration apparatus of 18th invention WHEREIN: The refrigerant circuit 10 includes the 2nd injection piping 59 which sends the liquid refrigerant of the gas-liquid separator 51 to the suction side of the compressor 11, and this 2nd invention It is provided with a liquid control valve 39 for adjusting the refrigerant flow rate of the injection pipe (59).

In the twenty-seventh aspect of the present invention, the liquid refrigerant separated by the gas-liquid separator (51) can be sent to the suction side of the compressor (11) via the second injection pipe (59). Therefore, if necessary, so-called liquid injection can be performed, and the liquid injection amount can be adjusted by changing the opening degree of the liquid control valve 39.

28th invention is the refrigeration apparatus of 18th invention WHEREIN: The some use side heat exchanger (22a, 22b, 22c) is connected in parallel to the refrigerant | coolant circuit 10, and each said use side heat exchanger (22a, 22b) is connected. And a plurality of flow regulating valves 61a, 61b, 61c for respectively adjusting the flow rate of the refrigerant flowing into the 22c.

In the twenty-eighth aspect of the present invention, a plurality of use-side heat exchangers (22a, 22b, 22c) are provided in the refrigerant circuit (10). That is, in this refrigeration apparatus, it is possible to simultaneously cool (cool) or heat (heat) the plurality of use-side heat exchangers 22a, 22b, 22c. The flow rate of refrigerant flowing into the use-side heat exchangers 22a, 22b, and 22c is adjusted by adjusting the opening degree of the plurality of flow rate regulating valves 61a, 61b, and 61c corresponding to the use-side heat exchangers 22a, 22b, and 22c. Can be adjusted separately.

In the twenty-ninth invention, in the refrigerating device of the eighteenth invention, carbon dioxide is used as the refrigerant in the refrigerant circuit (10).

In the twenty-ninth aspect of the present invention, carbon dioxide is charged into the refrigerant circuit 10 as a refrigerant. Since the carbon dioxide can increase the high and low differential pressure of the refrigerating cycle as compared with other refrigerants, the expansion power of the refrigerant obtained by the expander 12 can be increased.

[Effects of the Invention]

According to the first invention, by providing a temperature control means 23 capable of adjusting the temperature of the refrigerant flowing into the expander 12, it is possible to adjust the cost to flow rate of the refrigerant. Therefore, even if the operating conditions change, the flow rates of the compressor 11 and the expander 12 can be balanced. In this invention, even when the flow rate of the expander 12 is insufficient, it is not necessary to bypass a part of the refrigerant, so that the power obtained by the expander 12 does not decrease. Therefore, the COP can be prevented from lowering.

According to the second invention, the temperature adjusting means 23 is configured such that the cooling performance of the refrigerant flowing into the expander 12 is increased at the time of the cooling operation than at the heating operation. Therefore, when the refrigerating cycle is designed so that the flow rates of the expander 12 and the compressor 11 are balanced during the heating operation, the flow rate of the expander 12 is insufficient without bypassing the expander 12 during the cooling operation. Since it can prevent, it becomes possible to balance the flow volume of the expander 12 and the compressor 11 at the time of a cooling operation and a heating operation. Therefore, the fall of COP can be prevented.

According to the third aspect of the present invention, the internal heat exchanger (23) is provided in the refrigerant circuit (10), and during the cooling operation, the refrigerant after passing through the heat source side heat exchanger (21), which becomes a radiator, is used as an evaporator. By exchanging and cooling with the refrigerant before or after passing through the heat exchanger 22, the flow rate of the compressor 11 and the expander 12 is adjusted by adjusting the cost or flow rate of the refrigerant flowing into the expander 12. It can be balanced. Therefore, the fall of COP can be prevented.

According to the fourth aspect of the present invention, when the internal heat exchanger 23 is cooled, the heat transfer performance of the refrigerant flow passage 25 through which the refrigerant flows before or after passing through the use-side heat exchanger 22 serving as the evaporator is After passing through the heat source side heat exchanger 21 serving as a radiator, the refrigerant flows higher than the heat transfer performance of the refrigerant flow passage 24 through which the refrigerant flows, and during the heating operation, before passing through the heat source side heat exchanger 21 serving as the evaporator. Or the heat transfer performance of the refrigerant passage 24 through which the refrigerant flows after passing through is lower than the heat transfer performance of the refrigerant passage 25 through which the refrigerant flows through the use-side heat exchanger 22 serving as the radiator, so that the heat transfer performance is lowered. As in the present invention, the flow rate of the compressor 11 and the expander 12 can be balanced by adjusting the cost to flow rate of the refrigerant flowing into the expander 12. Therefore, the fall of COP can be prevented.

According to the fifth invention, the heat transfer fins 26 are provided in the predetermined refrigerant path 25 of the internal heat exchanger 23, so that the amount of heat exchange in the internal heat exchanger 23 during the cooling operation is larger than during the heating operation. By doing so, the cost to flow rate of the refrigerant flowing into the expander 12 can be adjusted. Therefore, the flow rate of the compressor 11 and the expander 12 can be balanced at the time of a heating operation and a cooling operation, and the fall of COP can be prevented.

According to the sixth aspect of the present invention, since the direction of the refrigerant flowing through the internal heat exchanger 23 is reversed during the cooling operation and the thermal operation, the cooling performance in the cooling operation becomes higher than in the heating operation. Cost to flow rate of the flowing refrigerant can be adjusted. Therefore, the flow rate of the compressor 11 and the expander 12 can be balanced at the time of a cooling operation and a heating operation, and the fall of COP can be prevented.

According to the seventh aspect of the present invention, the refrigerant before or after passing through the use-side heat exchanger 22 serving as the evaporator and the heat source side heat exchanger 21 serving as the radiator are used by using a double tube heat exchanger during the cooling operation. By heat-exchanging the refrigerant | coolant which passed through, the cost-effective flow volume of the refrigerant | coolant which flows into the expander 12 can be adjusted. Therefore, the flow rates of the compressor 11 and the expander 12 can be balanced in the cooling operation and the heating operation.

According to the eighth aspect of the present invention, the refrigerant before or after passing through the use-side heat exchanger 22 serving as the evaporator and the heat source-side heat exchanger 21 serving as the radiator by using the three-layer plate heat exchanger during the cooling operation. By heat exchanging the refrigerant after passing through, the cost to flow rate of the refrigerant flowing into the expander 12 can be adjusted. Therefore, the flow rates of the compressor 11 and the expander 12 can be balanced in the cooling operation and the heating operation.

According to the ninth aspect of the invention, the high temperature refrigerant flowing into the expander 12 is cooled only during the cooling operation by the temperature adjusting means 23, and the cooling of the high pressure refrigerant is stopped during the heating operation. The inlet refrigerant density de of the expander 12 can be increased at the time. Therefore, even when the mass flow rate Mc of the refrigerant passing through the compressor 11 becomes larger than during the heating operation during the cooling operation, the refrigerant sucked into the expander 12 by following this is cooled, thereby passing through the expander 12. Since the mass flow rate (Me) of the refrigerant can be increased to balance the mass flow rates (Mc, Me) of both refrigerants, the expander 12 and the compressor ( 11) can be designed. Moreover, in this invention, since the refrigerant | coolant flowing into the expander 12 does not need to be bypassed, the power obtained by the expander 12 also does not fall.

According to the tenth aspect of the present invention, by using the internal heat exchanger (23), the high-pressure refrigerant is exchanged with the low-pressure refrigerant during the cooling operation to cool it. Thus, by cooling only the high-pressure refrigerant flowing into the expander 12 during the cooling operation, the mass flow rate Me of the refrigerant passing through the expander 12 is increased, and the mass flow rate Mc of the refrigerant passing through the compressor 11 is increased. ), High efficiency operation is possible in both the cooling operation and the heating operation.

According to the eleventh invention, the internal heat exchanger (23) does not undergo heat exchange by sending high pressure refrigerant to both flow paths (24, 25) during the heating operation, and distributes both the high pressure refrigerant and the low pressure refrigerant during the cooling operation. To perform heat exchange. Thus, by cooling only the high-pressure refrigerant flowing into the expander 12 during the cooling operation, the mass flow rate Me of the refrigerant passing through the expander 12 is increased, and the mass flow rate Mc of the refrigerant passing through the compressor 11 is increased. ), High efficiency operation is possible in both cooling operation and heating operation.

According to the twelfth invention, the high pressure refrigerant bypasses the internal heat exchanger 23 during the heating operation, and during the cooling operation, both the high pressure refrigerant and the low pressure refrigerant are passed through the internal heat exchanger 23 to perform heat exchange. Configure to Thus, by cooling only the high-pressure refrigerant flowing into the expander 12 during the cooling operation, the mass flow rate Me of the refrigerant passing through the expander 12 is increased, and the mass flow rate Mc of the refrigerant passing through the compressor 11 is increased. ), High efficiency operation is possible in both cooling operation and heating operation.

According to the thirteenth invention, the low pressure refrigerant bypasses the internal heat exchanger (23) during the heating operation, and during the cooling operation, both the high pressure refrigerant and the low pressure refrigerant are passed through the internal heat exchanger (23) for heat exchange. Configure to Thus, by cooling only the high-pressure refrigerant flowing into the expander 12 during the cooling operation, the mass flow rate Me of the refrigerant passing through the expander 12 is increased, and the mass flow rate Mc of the refrigerant passing through the compressor 11 is increased. ), High efficiency operation is possible in both cooling operation and heating operation.

According to the fourteenth invention, in the cooling operation, the high pressure refrigerant after passing through the heat source side heat exchanger 21 is transferred to the low pressure refrigerant and heat before passing through the use side heat exchanger 22 in the internal heat exchanger 23. Replace to cool. Thus, by cooling only the high-pressure refrigerant flowing into the expander 12 during the cooling operation, the mass flow rate Me of the refrigerant passing through the expander 12 is increased, and the mass flow rate Mc of the refrigerant passing through the compressor 11 is increased. ), High efficiency operation is possible in both cooling operation and heating operation.

According to the fifteenth invention, during the cooling operation, the internal heat exchanger (23) exchanges the high pressure refrigerant after passing through the heat source side heat exchanger (21) with the low pressure refrigerant before passing through the utilization side heat exchanger (22). To cool. Thus, by cooling only the high-pressure refrigerant flowing into the expander 12 during the cooling operation, the mass flow rate Me of the refrigerant passing through the expander 12 is increased, and the mass flow rate Mc of the refrigerant passing through the compressor 11 is increased. ), High efficiency operation is possible in both cooling operation and heating operation.

According to the sixteenth aspect of the present invention, the high pressure refrigerant and the low pressure refrigerant are allowed to flow in the opposite direction to each other in the reverse direction, so that the high pressure refrigerant can be efficiently cooled. Therefore, during the cooling operation, the mass flow rate Me of the refrigerant passing through the expander 12 can be increased to be balanced with the mass flow rate Mc of the refrigerant passing through the compressor 11.

According to the seventeenth aspect of the present invention, by using carbon dioxide as the refrigerant of the refrigerant circuit 10, it is possible to increase the high and low differential pressure of the refrigerating cycle as compared with other refrigerants. Therefore, the recovery power of the compressor 11 can be improved, and the COP of the refrigerating device can be further improved.

According to the eighteenth invention, the liquid refrigerant separated in the gas-liquid separator 51 and the refrigerant sucked into the expander 12 are heat exchanged in the internal heat exchanger 50, whereby the suction refrigerant density de of the expander 12 is reduced. In other words, it is possible to increase the mass flow rate (Me). Therefore, by exchanging the refrigerant at a predetermined heat exchange amount in the internal heat exchanger 50, the refrigerant mass flow rates Mc and Me of the compressor 11 and the expander 12 can be balanced, and in this refrigeration apparatus, Desired refrigeration cycles can be performed.

In the present invention, as in Patent Document 2, the refrigerant mass flow rates Mc and Me can be balanced without bypassing a part of the refrigerant in the expander. That is, in the refrigeration apparatus of patent document 2, the expansion power of an expander falls and COP also falls, but in this invention, since all refrigerant | coolant can be introduce | transduced into the expander 12, such a fall of such COP can be avoided.

In the present invention, the liquid refrigerant separated by the gas-liquid separator 51 and the refrigerant sucked into the expander 12 are heat exchanged. Here, in the same type of coolant, the liquid coolant has a higher heat passing rate than the two-phase coolant or the gas coolant, so that the heat exchange rate in the internal heat exchange part 50 can be improved. . Therefore, the refrigerant sucked into the expander 12 can be cooled effectively, and as a result, the internal heat exchanger 50 and the gas-liquid separator 51 can be designed to be compact.

In addition, since the gas-liquid separator 51 also uses the internal heat exchange part 50 in this invention, compared with the case where the gas-liquid separator 51 and the internal heat exchange part 50 are separately installed, the refrigeration apparatus can be miniaturized. .

In the present invention, the liquid refrigerant separated by the gas-liquid separator 51 can be conveyed to a predetermined pipe or heat exchanger. As a result, for example, the pressure loss in the pipe can be reduced as compared with the case where the refrigerant in the two-phase state passes through the pipe or the heat exchanger. In addition, when the refrigerant in the two-phase state flows through the pipe or the heat exchanger, the refrigerant passage sound tends to be noise, but the present invention can prevent this.

According to the nineteenth invention, by configuring the heat exchange amount adjusting mechanism 60, the heat exchange amount of the internal heat exchange part 50 can be adjusted in accordance with the operating conditions. Therefore, in this refrigeration apparatus, it is possible to balance the refrigerant mass flow rates Me and Mc of the compressor 11 and the expander 12 in accordance with the change in the operating conditions.

According to the twentieth invention, the heat transfer tube 50 is disposed in the liquid reservoir 52 of the gas-liquid separator 51, whereby the suction refrigerant of the expander 12 flowing through the heat transfer tube 50 and the gas-liquid separator 51 are provided. Ensure that the liquid refrigerant separated from the heat exchanger is reliably exchanged. Thereby, the suction refrigerant density of the expander 12 can be reliably increased, and the refrigerant mass flow rates Me and Mc of the compressor 11 and the expander 12 can be balanced.

According to the twenty-first aspect of the present invention, the refrigerant heat exchange in the internal heat exchange part (50) is performed only during the cooling operation in which the refrigerant mass flow rate (Me) of the expander (12) tends to be smaller than the mass flow rate (Mc) of the compressor (11). Do it. Therefore, during the cooling operation, the refrigerant mass flow rates Me and Mc of the compressor 11 and the expander 12 can be reliably balanced.

On the other hand, during the heating operation, by designing the cylinder volume ratio of the expander 12 and the compressor 11 in accordance with the density ratio of the suction refrigerant density de of the expander 12 and the suction refrigerant density dc of the compressor 11. The refrigerant mass flow rates Me and Mc of the compressor 11 and the expander 12 can be balanced.

According to the twenty-second invention, the first and second electric valves 36 and 37 and the bypass pipe 57 are provided as the heat exchange amount adjusting mechanism 60. Then, by adjusting the opening degrees of the first and second electric valves 36 and 37 to a predetermined opening degree, the amount of refrigerant heat exchange in the heat transfer pipe 50 can be adjusted. Therefore, the refrigerant mass flow rates Me and Mc of the compressor 11 and the expander 12 can be balanced with high precision according to the operating conditions.

Moreover, by making the 1st electric valve 36 into a fully open state and making the 2nd electric valve 37 fully closed, the refrigerant | coolant can be circulated to the heat transfer pipe 50 only at the time of cooling operation, and the heat exchange of refrigerant can be carried out. . Therefore, the effect of the twenty-first invention can be obtained.

According to the twenty-third aspect of the invention, a cross switching valve 32 is provided as the heat exchange amount adjusting mechanism 60. By switching the crossover valve 32, the refrigerant flow can be changed in a state of sending the refrigerant to the heat transfer pipe 50 and in a state of not sending the refrigerant. Thereby, by switching the crossover valve 32, the refrigerant can be sent to the heat transfer pipe 50 only during the cooling operation, and the refrigerant can be heat exchanged. Therefore, the effect of 21st invention can be acquired easily.

According to the twenty-fourth invention, the first and second electromagnetic opening and closing valves 34 and 35 and the bypass pipe 57 are provided as the heat exchange amount adjusting mechanism 60. By opening the first solenoid valve 34 in the open state and closing the second solenoid valve in the closed state, the refrigerant can be sent to the heat transfer pipe 50 only during the cooling operation to perform the heat exchange of the refrigerant. Therefore, the effect of 21st invention can be acquired easily.

According to the twenty-fifth aspect of the present invention, a predetermined pipe path and check valves 81, 82, 83, 84 are provided as the heat exchange amount adjusting mechanism 60. As a result, the combination of these piping paths and the check valves 81, 82, 83, and 84 allows the refrigerant to be sent to the heat transfer pipe 50 only during the cooling operation, while not allowing the refrigerant to be sent to the heat transfer pipe 50 during the heating operation. Can be. Therefore, the twenty-first invention can be realized only by the switching control of the refrigerant circulation direction by the refrigerant switching means 31.

According to the twenty-sixth aspect of the present invention, the gas refrigerant separated by the gas-liquid separator 51 can be sent to the suction side of the compressor 11 to perform gas injection. Therefore, by adjusting the suction refrigerant superheat degree of the compressor 11, it is possible to perform the optimal refrigeration cycle control in this refrigerating device.

According to the twenty-seventh invention, the liquid refrigerant separated by the gas-liquid separator 51 can be sent to the suction side of the compressor 11 to perform liquid injection. Therefore, the same effects as in the twenty sixth invention can be obtained. Further, by combining the gas injection of the twenty-sixth invention with the liquid injection of the present invention, more precise freezing cycle control can be performed.

According to the present invention, the refrigerant oil contained in the refrigerant flowing out from the expander 12 can be returned to the suction side of the compressor 11 together with the liquid refrigerant separated from the gas-liquid separator 51.

According to the twenty-eighth aspect of the present invention, by providing the plurality of use-side heat exchangers 22a, 22b, and 22c, the refrigeration apparatus can be used for a so-called multifunctional air conditioner. In addition, since the flow rate of the refrigerant flowing into each of the use-side heat exchangers 22a, 22b, and 22c can be adjusted by the flow rate regulating valves 61a, 61b, and 61c, the cooling of each use-side heat exchanger 22a, 22b, 22c ( Cooling) ability, etc. can be adjusted separately.

Here, since the liquid refrigerant separated by the gas-liquid separator 51 can be sent to each of the use-side heat exchangers 22a, 22b, and 22c, for example, the flow regulating valves 61a, 61b, and 61c as compared with the refrigerant in the two-phase state. The flow rate adjustment at) can be easily performed. At the same time, noise caused by refrigerant pressure loss and refrigerant passage sound in a relatively long pipe can be reduced.

According to the twenty-ninth aspect of the present invention, by using carbon dioxide as the refrigerant in the refrigerant circuit 10, it is possible to increase the high and low differential pressure of the refrigerating cycle as compared with other refrigerants. Therefore, the recovery power of the expander 12 can be improved, and the COP of this freezing device can be further improved.

1 is a refrigerant circuit diagram of an air conditioner according to a first embodiment of the present invention.

2 is a schematic configuration diagram of an internal heat exchanger;

3 is a refrigerant circuit diagram of an air conditioner according to a second embodiment.

4 is a refrigerant circuit diagram of an air conditioner according to a third embodiment.

5 is a refrigerant circuit diagram of an air conditioner according to a fourth embodiment.

6 is a refrigerant circuit diagram of an air conditioner according to a fifth embodiment.

7 is a refrigerant circuit diagram of an air conditioner according to a sixth embodiment.

8 is a refrigerant circuit diagram of an air conditioner according to a seventh embodiment.

9 is a refrigerant circuit diagram of an air conditioner according to an eighth embodiment.

10 is a refrigerant circuit diagram of an air conditioner according to a ninth embodiment.

Fig. 11 is a refrigerant circuit diagram of an air conditioner according to a first modification of the ninth embodiment.

12 is a refrigerant circuit diagram of an air conditioner according to a second modification of the ninth embodiment.

13 is a refrigerant circuit diagram of an air conditioner according to a tenth embodiment.

14 is a refrigerant circuit diagram of an air conditioner according to a first modification of the tenth embodiment.

Fig. 15 is a refrigerant circuit diagram of an air conditioner according to a second modification of the tenth embodiment.

Fig. 16 is a refrigerant circuit diagram of an air conditioner according to a third modification of the tenth embodiment.

17 is a refrigerant circuit diagram of an air conditioner according to a fourth modification of the tenth embodiment.

18 is a refrigerant circuit diagram of an air conditioner according to an eleventh embodiment.

19 is a refrigerant circuit diagram of an air conditioner according to a twelfth embodiment.

20 is a refrigerant circuit diagram showing a refrigerant flow during the cooling operation of the twelfth embodiment;

21 is a refrigerant circuit diagram showing a refrigerant flow during the heating operation of the twelfth embodiment;

22 is a refrigerant circuit diagram of an air conditioner according to a modification of the twelfth embodiment.

23 is a refrigerant circuit diagram of an air conditioner according to a thirteenth embodiment.

24 is a refrigerant circuit diagram showing a refrigerant flow during the cooling operation of the thirteenth embodiment;

25 is a refrigerant circuit diagram showing a refrigerant flow during the heating operation of the thirteenth embodiment;

Fig. 26 is a refrigerant circuit diagram of an air conditioner according to a modification of the thirteenth embodiment.

27 is a refrigerant circuit diagram of an air conditioner according to a fourteenth embodiment.

28 is a refrigerant circuit diagram showing a refrigerant flow during the cooling operation of the fourteenth embodiment;

29 is a refrigerant circuit diagram showing a refrigerant flow during the heating operation of the fourteenth embodiment;

30 is a refrigerant circuit diagram of an air conditioner according to a modification of the fourteenth embodiment.

[Description of the code]

1: air conditioner (refrigerator) 10: refrigerant circuit

11 compressor 12 expander (expansion mechanism)

13: motor

21: outdoor heat exchanger (heat source side heat exchanger)

22: indoor heat exchanger (use side heat exchanger)

23: internal heat exchanger (temperature control means)

24: inner passage 25: outer passage

26: electrothermal fin 27: 1st flow path

28: the second euro

31: 1st cross switching valve (refrigerant switching mechanism)

32: 2nd crossover valve (heat exchange amount adjusting mechanism)

33: 3rd crossover valve (refrigerant changeover mechanism)

32a: bridge circuit 34: first solenoid valve

35: 2nd solenoid valve 36: 1st electric valve

37: second electric valve 38: gas control valve

39: liquid control valve 45, 46: bypass passage

50: heat pipe (internal heat exchanger) 51: gas-liquid separator

52: liquid reservoir 53: gas reservoir

55: separation gas pipe (first injection pipe) 57: bypass pipe

59: liquid injection pipe (second injection pipe) 60: heat exchange amount adjustment mechanism

61 flow rate regulating valve 61a, 61b, 61c 81-84 check valve

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail based on drawing.

[First embodiment]

1st Embodiment is related with the air conditioner 1 comprised with the refrigeration apparatus which concerns on this invention. This air conditioner 1 is equipped with the refrigerant circuit 10 as shown in FIG. And the air conditioner 1 of this 1st Embodiment is comprised so that a refrigerant | coolant may be circulated by the refrigerant | coolant circuit 10, and switching between cooling operation (cooling operation) and heating operation (heating operation).

The refrigerant circuit 10 is charged with carbon dioxide (CO ₂ ) as a refrigerant. The refrigerant circuit 10 includes a compressor 11, an expander 12, an outdoor heat exchanger (heat source side heat exchanger) 21, an indoor heat exchanger (use side heat exchanger) 22, and an internal heat exchanger 23. , The first four-way switching valve 31, and the second four-way switching valve (32) is provided.

The compressor 11 is composed of, for example, a rotating piston fluid machine. In other words, the compressor 11 is composed of a volumetric fluid machine having a constant displacement volume.

The inflator 12 is composed of, for example, a rotating piston fluid machine. In other words, the expander 12 is composed of a volumetric fluid machine with a constant exclusion volume.

Here, for the compressor 11 or the expander 12, the fluid machines constituting them are not limited to the rotary piston type, for example, the scroll type volumetric fluid machine may be used for the compressor 11 or the expander 12. You may use as.

In addition, the compressor 11 is mechanically connected to the expander 12 via the motor 13. The compressor 11 is rotationally driven by both the power obtained by the expansion of the refrigerant in the expander 12 and the power obtained by energizing the motor 13. The compressor 11 and the expander 12 are connected by one drive shaft, and each rotational speed is always the same. Therefore, the ratio of the exclusion amount of the compressor 11 and the exclusion amount of the expander 12 becomes constant.

The outdoor heat exchanger 21 is composed of a so-called cross fin fin tube type heat exchanger. The outdoor heat exchanger 21 is supplied with outdoor air by a fan outside the drawing. In this outdoor heat exchanger (21), heat exchange is performed between the supplied outdoor air and the refrigerant in the refrigerant circuit (10).

The indoor heat exchanger 22 is composed of a so-called cross fin fin tube heat exchanger. The indoor air is supplied to the indoor heat exchanger (22) by a fan outside the drawing. In this indoor heat exchanger (22), heat exchange is performed between the supplied indoor air and the refrigerant in the refrigerant circuit (10).

As for the said internal heat exchanger 23, as shown in FIG.2 (A) and FIG.2 (B) which is the sectional view of the BB line | wire, 2 which the inner flow path 24 and the outer flow path 25 are arrange | positioned adjacently It consists of a tube heat exchanger. The internal heat exchanger (23) is configured such that during cooling operation, the refrigerant after passing through the outdoor heat exchanger (21) serving as a radiator is heat exchanged with the refrigerant after passing through the indoor heat exchanger (22) serving as an evaporator. .

The inner flow path 24 of the internal heat exchanger 23 is a flow path through which the refrigerant after passing through the outdoor heat exchanger 21 serving as a radiator during the cooling operation flows, and is an evaporator during the heating operation. It becomes a flow path through which the refrigerant after passing through the group 21 flows. The outer flow passage 25 is a flow passage through which the refrigerant after passing through the indoor heat exchanger 22 serving as the evaporator during the cooling operation flows, and after passing through the indoor heat exchanger 22 serving as the radiator during the heating operation. It becomes a flow path through which the refrigerant flows.

The outer fin 25 is provided with a heat transfer fin 26. By providing this heat transfer fin 26, the internal heat exchanger 23 heat transfer performance of the refrigerant flow path (outer flow path 25) through which the refrigerant | coolant which flows through the indoor heat exchanger 22 which becomes an evaporator at the time of cooling operation flows. After passing through the outdoor heat exchanger 21 serving as a radiator, the refrigerant flows higher than the heat transfer performance of the refrigerant flow path (inner flow passage 24), and during the heating operation, passes through the outdoor heat exchanger 21 serving as the evaporator. The heat transfer performance of the coolant flow path (inner flow path 24) through which the coolant flows later becomes lower than the heat transfer performance of the coolant flow path (outer flow path 25) through which the coolant flows after passing through the indoor heat exchanger 22 serving as a radiator. do. Therefore, the internal heat exchanger 23 is configured such that the amount of heat exchange is greater in the cooling operation than in the heating operation, and the cooling performance of the refrigerant flowing into the expander 12 is increased.

In the refrigerant circuit 10, the discharge side of the compressor 11 is connected to the first port P1 of the first four-way switching valve 31, the second port P2 of the first four-way switching valve 31 is It is connected to the first end of the outdoor heat exchanger 21. The second end of the outdoor heat exchanger 21 is connected to the first port P1 of the second four-way switching valve 32 via the inner flow passage 24 of the internal heat exchanger 23, and the second four-way switching valve. The second port P2 of 32 is connected to the inflow side of the expander 12. The outlet side of the inflator 12 is connected to the third port P3 of the first four-way valve 31, and the fourth port P4 of the first four-way valve 31 is connected to the first port of the indoor heat exchanger 22. 1 is connected to the end. The second end of the indoor heat exchanger 22 is connected to the third port P3 of the second four-way switching valve 32 via the outer flow path 25 of the internal heat exchanger 23, and the second four-way switching valve. The fourth port P4 of 32 is connected to the suction side of the compressor 11.

The first four-way valve 31 is a state in which the first port (P1) is in communication with the second port (P2) and the third port (P3) is in communication with the fourth port (P4) (in a solid line in Figure 1). State), and the first port P1 communicates with the fourth port P4 and the second port P2 communicates with the third port P3 (the state indicated by a dotted line in FIG. 1). .

In addition, the second four-way switching valve 32 is a state in which the first port P1 communicates with the second port P2 and the third port P3 communicates with the fourth port P4 (solid line in FIG. 1). State), and the first port P1 communicates with the fourth port P4 and the second port P2 communicates with the third port P3 (the state indicated by a dotted line in FIG. 1). do.

Operation operation

Next, the operation | movement at the time of cooling operation and the heating operation of this air conditioner 1 is demonstrated.

(Cooling operation)

In the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state shown by the solid line in FIG. 1. When the motor 13 is energized in this state, the refrigerant is circulated in the refrigerant circuit 10 to perform a freezing cycle. At this time, the outdoor heat exchanger 21 becomes a radiator, and the indoor heat exchanger 22 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. The high pressure refrigerant flows into the outdoor heat exchanger 21 through the first four-way switching valve 31. In the outdoor heat exchanger (21), the high pressure refrigerant radiates heat to the outdoor air, whereby the temperature decreases.

The high pressure refrigerant flowing out from the outdoor heat exchanger 21 passes through the inner flow passage 24 of the internal heat exchanger 23, and at this time, exchanges with the refrigerant after passing through the evaporator that flows through the outer flow passage 25 to cool it. do. This refrigerant flows into the expander 12 through the second four-way switching valve (32). In the expander 12, the introduced high pressure refrigerant is expanded, and the internal energy of the high pressure refrigerant is converted into rotational power. By expansion in the expander 12, the high pressure refrigerant is reduced in pressure, and changes from a supercritical state to a gas-liquid two-phase state.

The low pressure refrigerant flowing out of the expander 12 flows into the indoor heat exchanger 22 through the first four-way switching valve 31. In the indoor heat exchanger (22), the low pressure refrigerant absorbs heat from the indoor air and evaporates. In the indoor heat exchanger (22), indoor air is cooled by a low pressure refrigerant, and the cooled indoor air is returned to the room.

The low pressure refrigerant flowing out from the indoor heat exchanger 22 passes through the outer flow passage 25 of the internal heat exchanger 23, and at this time, the refrigerant after passing through the outdoor heat exchanger 21 flowing through the inner flow passage 24. It is heated by heat exchange with. This refrigerant is sucked into the compressor (11) through the second four-way switching valve (32). The refrigerant sucked into the compressor 11 is compressed to a predetermined pressure and discharged from the compressor 11.

Here, in the internal heat exchanger (23), the heat transfer fins (26) are installed in the outer flow path (25) through which the refrigerant flows after passing through the indoor heat exchanger (22) that becomes the evaporator, and the outdoor heat exchanger (21) that becomes the radiator. The heat transfer fins 26 are not provided in the inner flow passage 24 through which the coolant flows after passing. Moreover, the heat transfer rate of the low pressure gas refrigerant after passing through the indoor heat exchanger 22 is relatively low, and the heat transfer rate of the supercritical refrigerant after passing through the outdoor heat exchanger 21 is relatively high. Therefore, during this cooling operation, since the heat transfer performance of the outer flow passage 25 through which the low pressure gas refrigerant with a relatively low heat transfer rate flows is increased in the internal heat exchanger 23, the low pressure gas refrigerant flowing through the outer flow passage 25, The supercritical refrigerant flowing through the inner flow passage 24 is heat exchanged relatively efficiently, and is cooled in the internal heat exchanger 23, so that the cost is small and the amount of refrigerant flowing into the expander 12 increases.

(Heating operation)

In the heating operation, the first four-way switching valve 31 and the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. When the motor 13 is energized in this state, the refrigerant is circulated in the refrigerant circuit 10 to perform a freezing cycle. At this time, the indoor heat exchanger 22 becomes a radiator, and the outdoor heat exchanger 21 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant, as in the cooling operation.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. This high pressure refrigerant flows into the indoor heat exchanger 22 through the first four way switching valve 31. In the indoor heat exchanger (22), the high pressure refrigerant radiates heat to the indoor air and the temperature is lowered. In the indoor heat exchanger (22), indoor air is heated by a high pressure refrigerant, and the heated indoor air is returned to the room.

The high pressure refrigerant flowing out of the indoor heat exchanger 22 passes through the outer flow passage 25 of the internal heat exchanger 23, and then flows into the expander 12 through the second four-way switching valve 32. In the expander 12, the introduced high pressure refrigerant is expanded, and the internal energy of the high pressure refrigerant is converted into rotational power. By expansion in the expander 12, the high pressure refrigerant is reduced in pressure, and changes from a supercritical state to a gas-liquid two-phase state.

The low pressure refrigerant flowing out of the expander 12 flows into the outdoor heat exchanger 21 through the first four-way switching valve 31. In the outdoor heat exchanger (21), the low pressure refrigerant absorbs heat from the outdoor air and evaporates.

The low pressure refrigerant flowing out of the outdoor heat exchanger 21 passes through the inner flow passage 24 of the internal heat exchanger 23, and is then sucked into the compressor 11 through the second four-way switching valve 32. The refrigerant sucked into the compressor 11 is compressed to a predetermined pressure and discharged from the compressor 11.

Here, in the internal heat exchanger (23), the heat transfer fins (26) are installed in the outer flow path (25) through which the refrigerant flows after passing through the indoor heat exchanger (22) that becomes the radiator, and the outdoor heat exchanger (21) that becomes the evaporator. The heat transfer fins 26 are not provided in the inner flow passage 24 through which the coolant flows after passing. Moreover, the heat transfer rate of the low pressure gas refrigerant after passing through the outdoor heat exchanger 21 is relatively low, and the heat transfer rate of the supercritical state refrigerant after passing through the indoor heat exchanger 22 is relatively high. Therefore, during this heating operation, since the heat transfer performance of the inner passage 24 through which the low-pressure gas refrigerant with a relatively low heat transfer rate flows is low in the internal heat exchanger 23, the supercritical refrigerant flowing through the outer passage 25 is performed. The low pressure gas refrigerant flowing through the inner passage 24 is hardly heat exchanged.

Effect of the first embodiment

In the first embodiment, in the internal heat exchanger 23, during the cooling operation, the refrigerant after passing through the indoor heat exchanger 22 serving as the evaporator flows through the outer flow path 25, and the outdoor heat exchanger 21 serving as the radiator. After passing through), the refrigerant flows through the inner passage (24). In the heating operation, the refrigerant after passing through the indoor heat exchanger 22 serving as the radiator flows through the outer passage 25, and the refrigerant after passing through the outdoor heat exchanger 21 serving as the evaporator passes through the inner passage 24. Flow. And the heat transfer fin 26 is provided in the outer side flow path 25.

As a result, during the cooling operation, the gas refrigerant after passing through the evaporator flows through the outer flow path 25, so that the refrigerant in the outer flow path 25 and the refrigerant in the inner flow path 24 are heat exchanged relatively efficiently, and thus supercritical The refrigerant in the state is lowered in temperature and flows into the expander 12. On the other hand, during the heating operation, since the gas refrigerant after passing through the evaporator flows through the inner flow passage 24, the refrigerant in the outer flow passage 25 and the refrigerant in the inner flow passage 24 are hardly heat-exchanged, and the supercritical state The coolant flows into the expander 12 with almost no change in temperature.

Therefore, during the cooling operation, the refrigerant flowing into the expander 12 is cooled in the internal heat exchanger 23 than in the heating operation, so that the cost is small and the flow rate of the expander 12 increases. Thus, in this embodiment, the flow rate of the compressor 11 and the expander 12 can be balanced by adjusting the cost or flow rate of the refrigerant flowing into the expander 12 during the cooling operation.

In addition, during the cooling operation in which the amount of circulation of the refrigerant is increased as compared with the heating operation, the refrigerant does not have to bypass the expander 12, so that the recovery power of the expander 12 does not decrease, thus preventing the COP from decreasing. It becomes possible.

Second Embodiment

In the second embodiment, in the refrigerant circuit 10 of the first embodiment, a receiver 41 is provided between the expander 12 and the first four-way switching valve 31. In other words, in the second embodiment, the receiver 41 is provided on the outlet side of the expander 12.

As shown in FIG. 3, the outlet side of the inflator 12 is connected to the inlet of the receiver 41, and the outlet of the receiver 41 is connected to the third port P3 of the first four-way valve 31. do. In addition, a liquid injection pipe 42 connected to the lower end of the receiver 41 and a gas discharge pipe 43 connected to the upper end of the receiver 41 are connected to the suction side of the compressor 11. The first electric valve EV1 is provided in the liquid injection pipe 42, and the second electric valve EV2 is provided in the gas discharge pipe 43, and the flow rate of the refrigerant can be adjusted. The rest of the configuration is the same as in the first embodiment.

Operation operation

During the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state shown by the solid line in FIG. The refrigerant discharged from the compressor 11 in this state is the first cross switching valve 31, the outdoor heat exchanger 21, the inner flow passage 24 of the internal heat exchanger 23, and the second cross switching valve 32. , The expander 12, the receiver 41, the first four-way switching valve 31, the indoor heat exchanger 22, the outer flow path 25 of the internal heat exchanger 23, and the second four-way switching valve 32. In turn, they are sucked into the compressor 11 again.

In the internal heat exchanger (23), the supercritical state refrigerant after passing through the outdoor heat exchanger (21) flows through the inner passage (24), and the low pressure gas refrigerant after passing through the indoor heat exchanger (22) passes through the outer passage (25). ), The refrigerant flowing through the inner passage 24 and the refrigerant flowing through the outer passage 25 are heat exchanged. As a result, the supercritical refrigerant is cooled in the internal heat exchanger 23 and flows into the expander 12 in a state where the cost is reduced.

In this cooling operation, by adjusting the opening degree of the electric valve of the liquid injection pipe 42, the suction superheat degree control of the compressor 11 and the oil recovery operation are possible. The gas of the receiver 41 can also be discharged by adjusting the opening degree of the electric valve of the gas discharge pipe 43. In addition, when the opening degree of the 1st transmission valve EV1 of the liquid injection pipe 42 and the 2nd transmission valve EV2 of the gas discharge pipe 43 is adjusted, when the capacity | capacitance lacks in the compressor 11 at the time of operation, It may also compensate for the lack of capacity.

In the heating operation, the first four-way switching valve 31 and the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. The refrigerant discharged from the compressor 11 in this state is the first four-way switching valve 31, the indoor heat exchanger 22, the outer flow passage 25 of the internal heat exchanger 23, the second four-way switching valve (32). , The expander 12, the receiver 41, the first four-way switching valve 31, the outdoor heat exchanger 21, the inner flow path 24 of the internal heat exchanger 23, and the second four-way switching valve 32. In turn, they are sucked into the compressor 11 again.

In the internal heat exchanger (23), the supercritical state refrigerant after passing through the indoor heat exchanger (22) flows through the outer passage (25), and the low pressure gas refrigerant after passing through the outdoor heat exchanger (21) passes through the inner passage (24). ), The refrigerant flowing through the inner flow passage 24 and the refrigerant flowing through the outer flow passage 25 are hardly heat exchanged. As a result, the refrigerant in the supercritical state flows into the expander 12 with almost no change in temperature even though it passes through the internal heat exchanger 23.

Effects of the Second Embodiment

Also in this second embodiment, during the cooling operation, since the refrigerant after passing through the indoor heat exchanger 22 serving as the evaporator flows through the outer flow passage 25, the refrigerant of the outer flow passage 25 and the inner flow passage 24 are separated. The refrigerant is heat exchanged relatively efficiently, and the supercritical refrigerant flows into the expander 12 in a state where the temperature is lowered and the cost is reduced. On the other hand, during the heating operation, since the gas refrigerant after passing through the outdoor heat exchanger 21 serving as the evaporator flows through the inner passage 24, the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are almost heat. Unchanged, the supercritical refrigerant flows into the expander 12 with little change in temperature.

As described above, since the cost or flow rate can be adjusted by adjusting the temperature of the refrigerant flowing into the expander 12 during the cooling operation, the flow rates of the compressor 11 and the expander 12 are balanced, thereby lowering the COP. It becomes possible to prevent.

[Third Embodiment]

In the third embodiment, the receiver 41 is provided at a position different from that of the second embodiment in the refrigerant circuit 10 of the first embodiment. In this third embodiment, the supercritical refrigerant flowing out of the radiator flows into the internal heat exchanger 23, while the low pressure refrigerant flowing out of the evaporator passes through the receiver 41 and then the internal heat exchanger 23. It is configured to flow into.

As shown in FIG. 4, the piping which connects the 2nd end of the indoor heat exchanger 22 and the outer side flow path 25 of the internal heat exchanger 23 is this indoor heat exchanger 22 and the internal heat exchanger 23. As shown in FIG. The first solenoid valve SV1 is provided therebetween, and branches immediately before the first solenoid valve SV1 and is connected to the receiver 41 via the third solenoid valve SV3. In addition, a pipe connecting the second end of the outdoor heat exchanger 21 and the inner flow passage 24 of the internal heat exchanger 23 has a second solenoid valve between the outdoor heat exchanger 21 and the internal heat exchanger 23. While SV2 is provided, it branches off immediately before the second solenoid valve SV2 and is connected to the receiver 41 via the fourth solenoid valve SV4.

In the receiver 41, a liquid injection pipe 42 provided with an electric valve EV is connected to the suction side of the compressor 11. In addition, the gas discharge pipe 43 of the receiver 41 is branched into two, and the first branch pipe 43a is interposed inside the first check valve CV1 which prohibits the flow of the refrigerant to the receiver 41. The second branch pipe 43b is connected to the outer flow passage 25 of the heat exchanger 23, and the second branch pipe 43b intersects the internal check exchanger CV2 through the second check valve CV2 which prohibits the flow of the refrigerant to the receiver 41. It is connected to the inner flow path 24 of 23.

The rest of the configuration is the same as in the first embodiment.

Operation operation

In the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state shown by the solid line in FIG. In this cooling operation, the first solenoid valve SV1 and the fourth solenoid valve SV4 are closed, and the second solenoid valve SV2 and the third solenoid valve SV3 are “opened”. .

The refrigerant discharged from the compressor 11 in this state is the first cross switching valve 31, the outdoor heat exchanger 21, the inner flow passage 24 of the internal heat exchanger 23, and the second cross switching valve 32. , The expander 12, the first four-way switching valve 31, the indoor heat exchanger 22, the receiver 41, the outer flow path 25 of the internal heat exchanger 23, and the second four-way switching valve 32. In turn, they are sucked into the compressor 11 again.

In the internal heat exchanger (23), the supercritical state refrigerant after passing through the outdoor heat exchanger (21) flows through the inner passage (24), and the low pressure gas refrigerant after passing through the indoor heat exchanger (22) passes through the outer passage (25). ), The refrigerant flowing through the inner passage 24 and the refrigerant flowing through the outer passage 25 are heat exchanged. As a result, the supercritical refrigerant is cooled in the internal heat exchanger 23 and flows into the expander 12 in a state where the cost is reduced.

In the heating operation, the first four-way switching valve 31 and the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. In this cooling operation, the first solenoid valve SV1 and the fourth solenoid valve SV4 are "open", and the second solenoid valve SV2 and the third solenoid valve SV3 are "closed." .

The refrigerant discharged from the compressor 11 in this state is the first four-way switching valve 31, the indoor heat exchanger 22, the outer flow passage 25 of the internal heat exchanger 23, the second four-way switching valve (32). The inner passage 24 of the expander 12, the first four-way switching valve 31, the outdoor heat exchanger 21, the receiver 41, the internal heat exchanger 23, and the second four-way switching valve 32. In turn, they are sucked into the compressor 11 again.

In the internal heat exchanger (23), the supercritical state refrigerant after passing through the indoor heat exchanger (22) flows through the outer passage (25), and the low pressure gas refrigerant after passing through the outdoor heat exchanger (21) passes through the inner passage (24). ), The refrigerant flowing through the inner flow passage 24 and the refrigerant flowing through the outer flow passage 25 are hardly heat exchanged. As a result, the refrigerant in the supercritical state flows into the expander 12 with almost no change in temperature even though it passes through the internal heat exchanger 23.

Effect of the third embodiment

Also in this third embodiment, at the time of cooling operation, since the gas refrigerant after passing through the indoor heat exchanger 22 serving as the evaporator flows through the outer flow passage 25, the refrigerant of the outer flow passage 25 and the inner flow passage 24 are separated. The refrigerant is heat exchanged relatively efficiently, and the supercritical refrigerant flows into the expander 12 in a state where the temperature is lowered and the cost is reduced. On the other hand, during the heating operation, since the gas refrigerant after passing through the outdoor heat exchanger 21 serving as the evaporator flows through the inner passage 24, the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are almost heat. Unchanged, the supercritical refrigerant flows into the expander 12 with almost no change in temperature.

As described above, since the cost or flow rate can be adjusted by adjusting the temperature of the refrigerant flowing into the expander 12 during the cooling operation, the flow rates of the compressor 11 and the expander 12 are balanced, and the COP It becomes possible to prevent a fall.

Fourth Embodiment

According to the fourth embodiment, the flow directions of the refrigerants in the inner flow passage 24 and the outer flow passage 25 of the internal heat exchanger 23 become opposite to each other (counter flow) during the cooling operation. It is an example that the same direction (parallel flow) in the operation.

As shown in FIG. 5, in this 4th Embodiment, the 3rd crossover valve 33 is provided between the outdoor heat exchanger 21 and the internal heat exchanger 23, and the inner flow path of the internal heat exchanger 23 ( 24) Make sure the flow direction is reversed during cooling operation and heating operation. To this end, the second end of the outdoor heat exchanger 21 is connected to the first port P1 of the third crossover valve 33, and the second port P2 of the third crossover valve 33 is internal heat exchanged. The inner port 24 of the machine 23 is connected to the third port P3 of the third four-way valve 33, and the fourth port P4 of the third four-way valve 33 is It is connected to the first port P1 of the second four-way switching valve 32.

The third four-way valve 33 is a state in which the first port (P1) is in communication with the second port (P2) and the third port (P3) is in communication with the fourth port (P4) (in a solid line in Figure 1). State) and the first port P1 communicates with the third port P3 and the second port P2 communicates with the fourth port P4 (the state indicated by a dotted line in FIG. 1). .

The rest of the configuration is the same as in the first embodiment.

Operation operation

In the cooling operation, the first four-way switching valve 31, the second four-way switching valve 32, and the third four-way switching valve 33 are switched to the state shown by the solid line in FIG. The refrigerant discharged from the compressor 11 in this state is the first flow path switching valve 31, the outdoor heat exchanger 21, the third flow path switching valve 33, and the inner flow path 24 of the internal heat exchanger 23. , The third flow path switching valve 33, the second flow path switching valve 32, the expander 12, the first flow path switching valve 31, the indoor heat exchanger 22, and the outer flow path of the internal heat exchanger 23 ( 25), the second four-way switching valve (32) flows in turn, and is again sucked into the compressor (11).

In the internal heat exchanger (23), the refrigerant passing through the inner heat exchanger (24) after passing through the outdoor heat exchanger (21), and the refrigerant passing through the outer flow path (25) after passing through the indoor heat exchanger (22) At the same time, the supercritical refrigerant flows through the inner flow passage 24 and the gas coolant flows through the outer flow passage 25, so that the coolant flowing through the inner flow passage 24 and the outer flow passage 25 flow. Is heat exchanged efficiently. As a result, the supercritical refrigerant is cooled in the internal heat exchanger 23 and flows into the expander 12 while the cost is reduced.

In the heating operation, the first four-way switching valve 31, the second four-way switching valve 32, and the third four-way switching valve 33 is switched to the state shown by the dotted line in FIG. The refrigerant discharged from the compressor 11 in this state is the first four-way switching valve 31, the indoor heat exchanger 22, the outer flow passage 25 of the internal heat exchanger 23, the second four-way switching valve (32). , The expander 12, the first four-way switching valve 31, the outdoor heat exchanger 21, the third four-way switching valve 33, the inner passage 24 of the internal heat exchanger 23, the third four-way switching valve ( 33), the second four-way switching valve (32) flows in turn, and is again sucked into the compressor (11).

In the internal heat exchanger (23), refrigerant passing through the inner heat exchanger (22) after passing through the indoor heat exchanger (22), and refrigerant passing through the inner flow path (24) after passing through the outdoor heat exchanger (21) The supercritical refrigerant flows through the outer passage 25 and the gas coolant flows through the inner passage 24, so that the refrigerant flowing through the inner passage 24 and the outer passage 25 flow in the same direction. The flowing refrigerant is hardly heat exchanged. Thus, the refrigerant in the supercritical state flows into the expander 12 with almost no change in temperature even though it passes through the internal heat exchanger 23.

Specifically, the heat exchange efficiency of the counter flow is 0.8, the heat exchange efficiency of the parallel flow is 0.3, and the heat passing rate during the cooling operation is 2.34 during the heating operation due to the difference in heat transfer area between the outer flow passage 25 and the inner flow passage 24. When doubled, the heat transfer performance at the time of cooling is compared with the heating time,

2.34 × 0.8 / 0.3 = 6.24 times.

Effect of Fourth Embodiment

In the fourth embodiment, in the cooling operation, the gas refrigerant after passing through the indoor heat exchanger 22 serving as the evaporator flows through the outer flow passage 25, and the refrigerant of the outer flow passage 25 and the inner flow passage 24. Since the refrigerants of the flow paths flow in the opposite directions, the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are heat exchanged relatively efficiently, and the refrigerant in the supercritical state has a low temperature, resulting in a low cost. In the inflator 12. On the other hand, during the heating operation, the gas refrigerant after passing through the outdoor heat exchanger 21 serving as the evaporator flows through the inner passage 24, where the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are equal to each other. Since it flows toward the direction, the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are hardly heat exchanged, and the refrigerant in the supercritical state flows into the expander 12 with almost no change in temperature.

As described above, since the cost or flow rate can be adjusted by adjusting the temperature of the refrigerant flowing into the expander 12 during the cooling operation, the flow rate of the compressor 11 and the expander 12 is balanced, and the COP is lowered. It becomes possible to prevent.

[Fifth Embodiment]

The fifth embodiment uses a three-layer plate heat exchanger instead of the double tube heat exchanger as the internal heat exchanger 23 in the first embodiment. The internal heat exchanger 23 includes an inner flow passage 24 located at the center, a first outer flow passage 25A and a second outer flow passage 25B disposed adjacent to the outside of the inner flow passage 24. do.

As shown in FIG. 6, the inner flow path 24 of the internal heat exchanger 23 is a flow path through which the refrigerant flows after passing through the outdoor heat exchanger 21 serving as a radiator during the cooling operation. In this case, a coolant flows through the outdoor heat exchanger 21 serving as an evaporator. Moreover, the 2nd outer side flow path 25B becomes a flow path through which the refrigerant | coolant which passed after passing the indoor heat exchanger 22 which becomes an evaporator at the time of cooling operation flows, and the indoor heat exchanger 22 which becomes a radiator at the time of a heating operation. It becomes a flow path through which the refrigerant after passing. 25 A of 1st outer side flow paths become a flow path through which the low pressure refrigerant | coolant which passed after passing the 2nd outer side flow path 25B at the time of cooling operation, and the inner side passage 24 at the time of heating operation, respectively.

The heat-transfer fin 26 is provided in the 1st outer side flow path 25A of this internal heat exchanger 23 at the side surface of the inner side flow path 24. By providing this heat transfer fin 26, the internal heat exchanger 23 of the refrigerant flow path (1st outer flow path 25A) which the refrigerant | coolant which flows after passing through the indoor heat exchanger 22 which becomes an evaporator at the time of cooling operation flows. The heat transfer performance is higher than the heat transfer performance of the refrigerant flow path (inner flow passage 24) through which the refrigerant after passing through the outdoor heat exchanger 21 serving as the radiator, and during the heating operation, the outdoor heat exchanger 21 serving as the evaporator is The heat transfer performance of the refrigerant flow passage (inner flow passage 24) through which the refrigerant flows through passes the heat transfer of the refrigerant flow passage (first outer flow passage 25A) through which the refrigerant flows after passing through the indoor heat exchanger 22 serving as a radiator. Configured to be lower than performance. Therefore, the internal heat exchanger 23 is configured such that the cooling performance of the refrigerant flowing into the expander 12 is higher at the time of the cooling operation than at the heating operation.

In the refrigerant circuit 10 of this embodiment, the second end of the outdoor heat exchanger 21 is connected to the first port of the second cross switching valve 32 via the inner flow passage 24 of the internal heat exchanger 23. It is connected to P1, and the second port P2 of the second four-way switching valve 32 is connected to the inflow side of the expander 12. In addition, the second end of the indoor heat exchanger 22 is connected to the third port P3 of the second four-way switching valve 32 via the second outer flow passage 25B of the internal heat exchanger 23. The fourth port P4 of the two-way switching valve 32 is connected to the suction side of the compressor 11 via the first outer flow passage 25A of the internal heat exchanger 23.

The rest of the configuration is the same as in the first embodiment.

Operation operation

In the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state shown by the solid line in FIG. The refrigerant discharged from the compressor 11 in this state is the first cross switching valve 31, the outdoor heat exchanger 21, the inner flow passage 24 of the internal heat exchanger 23, and the second cross switching valve 32. , The expander 12, the first four-way switching valve 31, the indoor heat exchanger 22, the second outer flow path 25B of the internal heat exchanger 23, the second four-way switching valve 32, the internal heat exchanger ( The first outer flow path 25A of 23 is sequentially flowed into the compressor 11 again.

In the internal heat exchanger 23, the supercritical refrigerant passing through the inner flow passage 24 before passing through the outdoor heat exchanger 21, and the second outer flow passage 25B after passing through the indoor heat exchanger 22. The gas refrigerant passing through) has a large temperature difference but a parallel flow, so that the amount of heat exchange is relatively small. On the other hand, the supercritical refrigerant passing through the inner flow passage 24 and the gas refrigerant passing through the first outer flow passage 25A after passing through the second outer flow passage 25B are counter flows with a large temperature difference. Furthermore, since gas refrigerant flows through the first outer flow path 25A, heat exchange is efficiently performed. As a result, the supercritical refrigerant is cooled in the internal heat exchanger 23 and flows into the expander 12 in a state where the cost is reduced.

In the heating operation, the first four-way switching valve 31 and the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. In this state, the refrigerant discharged from the compressor 11 includes the first four-way switching valve 31, the indoor heat exchanger 22, the second outer flow path 25B of the internal heat exchanger 23, and the second four-way switching valve ( 32, expander 12, the first four-way switching valve 31, the outdoor heat exchanger 21, the inner passage 24 of the internal heat exchanger 23, the second four-way switching valve 32, the internal heat exchanger ( The first outer flow path 25A of 23 is sequentially flowed into the compressor 11 again.

In the internal heat exchanger (23), after passing through the indoor heat exchanger (22), the supercritical refrigerant passing through the first outer flow passage (25B), and the inner flow passage (24) after passing through the outdoor heat exchanger (21). The low pressure gas refrigerant passing through) has a large temperature difference but is a parallel flow, so that the amount of heat exchange is relatively small. In addition, since the gas refrigerant passing through the inner flow passage 24 and the gas refrigerant passing through the first outer flow passage 25A thereafter do not have a temperature difference, the amount of heat exchange is almost zero. As a result, the supercritical refrigerant flows into the expander 12 with little change in temperature even though it passes through the internal heat exchanger 23.

Effect of the fifth embodiment

Also in this fifth embodiment, at the time of cooling operation, the gas refrigerant after passing through the indoor heat exchanger 22 serving as the evaporator flows through the outer flow passage 25 (first outer flow passage 25A) and the first outer flow passage. Since the refrigerant of 25A and the refrigerant of the inner passage 24 flow in the opposite directions to each other, the refrigerant of the first outer passage 25A and the refrigerant of the inner passage 24 are heat exchanged relatively efficiently, and the supercritical state Of refrigerant flows into the expander 12 in a state where the temperature decreases and the cost is small. In the heating operation, on the other hand, the gas refrigerant after passing through the outdoor heat exchanger 21 serving as the evaporator flows through the inner flow passage 24 and the first outer flow passage 25A, and at this time, the supercritical state of the second outer flow passage 25B. Since the heat is hardly exchanged with the refrigerant, the supercritical refrigerant flows into the expander 12 with almost no change in temperature.

As described above, by adjusting the temperature of the refrigerant flowing into the expander 12 during the cooling operation, the cost or the flow rate can be adjusted, so that the flow rates of the compressor 11 and the expander 12 are balanced to lower the COP. It becomes possible to prevent.

[Sixth Embodiment]

The sixth embodiment is an example in which the refrigerant after passing through the radiator and the refrigerant before flowing into the evaporator are heat exchanged in the internal heat exchanger 23 (double tube heat exchanger) during the cooling operation.

As shown in FIG. 7, the discharge side of the compressor 11 is connected to the first port P1 of the first four-way valve 31, and the second port P2 of the first four-way valve 31 is outdoors. It is connected to the first end of the heat exchanger 21. The second end of the outdoor heat exchanger 21 is connected to the first port P1 of the second four-way switching valve 32 via the inner flow passage 24 of the internal heat exchanger 23, and the second four-way switching valve. The second port P2 of 32 is connected to the inflow side of the expander 12. The outlet side of the inflator 12 is connected to the third port P3 of the second four-way switching valve 32, and the fourth port P4 of the second four-way switching valve 32 is the outside of the internal heat exchanger 23. It is connected to the 1st end of the indoor heat exchanger 22 via the flow path 25. As shown in FIG. The second end of the indoor heat exchanger 22 is connected to the third port P3 of the first four-way valve 31, and the fourth port P4 of the first four-way valve 31 is the compressor 11. It is connected to the suction side of the.

Operation operation

During the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state shown by the solid line in FIG. The refrigerant discharged from the compressor 11 in this state is the first cross switching valve 31, the outdoor heat exchanger 21, the inner flow passage 24 of the internal heat exchanger 23, and the second cross switching valve 32. , The expander 12, the second four-way switching valve 32, the outer flow path 25 of the internal heat exchanger 23, the indoor heat exchanger 22, and the first four-way switching valve 31 in order, and then the compressor ( 11) is inhaled.

In the internal heat exchanger (23), the supercritical refrigerant after passing through the outdoor heat exchanger (21) flows through the inner passage (24), and the low pressure refrigerant before passing through the indoor heat exchanger (22) passes through the outer passage (25). ), The refrigerant flowing through the inner passage 24 and the refrigerant flowing through the outer passage 25 are heat exchanged. As a result, the supercritical refrigerant is cooled in the internal heat exchanger 23 and flows into the expander 12 in a state where the cost is reduced.

In the heating operation, the first four-way switching valve 31 and the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. The refrigerant discharged from the compressor 11 in this state is the first four-way switching valve 31, the indoor heat exchanger 22, the outer flow passage 25 of the internal heat exchanger 23, the second four-way switching valve (32). , The expander 12, the second four-way switching valve 32, the inner flow path 24 of the internal heat exchanger 23, the outdoor heat exchanger 21, and the first four-way switching valve 31 in order, and then the compressor ( 11) is inhaled.

In the internal heat exchanger (23), the supercritical refrigerant after passing through the indoor heat exchanger (22) flows through the outer passage (25), and the low pressure refrigerant before passing through the outdoor heat exchanger (21) passes through the inner passage (24). ), The refrigerant flowing through the inner flow passage 24 and the refrigerant flowing through the outer flow passage 25 are hardly heat exchanged. Thus, the refrigerant in the supercritical state flows into the expander 12 with almost no change in temperature even though it passes through the internal heat exchanger 23.

Effect of the sixth embodiment

In the sixth embodiment, during the cooling operation, the refrigerant before passing through the indoor heat exchanger 22 serving as the evaporator flows through the outer flow passage 25, so that the refrigerant of the outer flow passage 25 and the inner flow passage 24 are separated. The refrigerant is heat exchanged relatively efficiently, and the supercritical refrigerant flows into the expander 12 in a state where the temperature is lowered and the cost is reduced. In the heating operation, on the other hand, since the refrigerant before passing through the outdoor heat exchanger 21 serving as the evaporator flows through the inner passage 24, the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are hardly exchanged with each other. In addition, the supercritical refrigerant flows into the expander 12 with almost no change in temperature.

As described above, since the cost or flow rate can be adjusted by adjusting the temperature of the refrigerant flowing into the expander 12 during the cooling operation, the flow rate of the compressor 11 and the expander 12 is balanced, and thus the COP It becomes possible to prevent a fall.

[Seventh Embodiment]

In the seventh embodiment, the bridge circuit 32a is used in place of the second four-way switching valve 32 in the refrigerant circuit 10 of the sixth embodiment.

As shown in Fig. 8, the bridge circuit 32a is formed by connecting four conduits in a bridge shape and has four ports P1, P2, P3, and P4. Each of the four pipelines is provided with a check valve (CV). The check valve CV includes a refrigerant flow from the first port P1 to the second port P2, a refrigerant flow from the third port P3 to the fourth port P4, and a third port ( It is installed in each conduit to allow the refrigerant flow from P3 to the first port P1 and the refrigerant flow from the fourth port P4 to the second port P2.

The inner flow passage 24 of the internal heat exchanger 23 is connected to the first port P1 of the bridge circuit 32a. The second port P2 of the bridge circuit 32a is connected to the inflow side of the expander 12. The outflow side of the inflator 12 is connected to the third port P3 of the bridge circuit 32a. The fourth port P4 of the bridge circuit 32a is connected to the outer flow passage 25 of the internal heat exchanger 23.

The rest of the configuration is the same as in the sixth embodiment.

Operation operation

During the cooling operation, the first four-way switching valve 31 is switched to the state shown by the solid line in FIG. The refrigerant discharged from the compressor 11 in this state is the first four-way switching valve 31, the outdoor heat exchanger 21, the inner flow passage 24 of the internal heat exchanger 23, the bridge circuit 32a, the expander 12, the bridge circuit 32a, the outer flow passage 25 of the internal heat exchanger 23, the indoor heat exchanger 22, and the first four-way switching valve 31 are sequentially flown, and are again sucked into the compressor 11. .

In the internal heat exchanger (23), the supercritical refrigerant after passing through the outdoor heat exchanger (21) flows through the inner passage (24), and the low pressure refrigerant before passing through the indoor heat exchanger (22) passes through the outer passage (25). ), The refrigerant flowing through the inner passage 24 and the refrigerant flowing through the outer passage 25 are heat exchanged. As a result, the supercritical refrigerant is cooled in the internal heat exchanger 23 and flows into the expander 12 in a state where the cost is reduced.

During the heating operation, the first four-way switching valve 31 is switched to the state shown by the dotted line in FIG. The refrigerant discharged from the compressor 11 in this state is the first four-way switching valve 31, the indoor heat exchanger 22, the outer flow passage 25 of the internal heat exchanger 23, the bridge circuit 32a, the expander ( 12), the bridge circuit 32a, the inner flow passage 24 of the internal heat exchanger 23, the outdoor heat exchanger 21, and the first four-way switching valve 31 are sequentially flown, and are again sucked into the compressor 11.

In the internal heat exchanger (23), the supercritical refrigerant after passing through the indoor heat exchanger (22) flows through the outer passage (25), and the low pressure refrigerant before passing through the outdoor heat exchanger (21) passes through the inner passage (24). ), The refrigerant flowing through the inner flow passage 24 and the refrigerant flowing through the outer flow passage 25 are hardly heat exchanged. Thus, the refrigerant in the supercritical state flows into the expander 12 with almost no change in temperature even though it passes through the internal heat exchanger 23.

Effect of the seventh embodiment

In the seventh embodiment, during the cooling operation, the refrigerant before passing through the indoor heat exchanger 22 serving as the evaporator flows through the outer flow passage 25, so that the refrigerant of the outer flow passage 25 and the inner flow passage 24 are separated. The refrigerant is heat exchanged relatively efficiently, and the supercritical refrigerant flows into the expander 12 in a state where the temperature is lowered and the cost is reduced. In the heating operation, on the other hand, since the refrigerant before passing through the outdoor heat exchanger 21 serving as the evaporator flows through the inner passage 24, the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are hardly exchanged with each other. In addition, the supercritical refrigerant flows into the expander 12 with almost no change in temperature.

As described above, since the cost or flow rate can be adjusted by adjusting the temperature of the refrigerant flowing into the expander 12 during the cooling operation, the flow rates of the compressor 11 and the expander 12 are balanced, thereby lowering the COP. It becomes possible to prevent.

[Eighth Embodiment]

In the sixth embodiment, in the sixth embodiment, the refrigerant flow directions in the inner flow passage 24 and the outer flow passage 25 of the internal heat exchanger 23 are opposite to each other in the cooling operation, and are mutually opposite in the heating operation. This is an example to be in the same direction.

As shown in Fig. 9, in this eighth example, in the refrigerant circuit 10 of the sixth embodiment, a third four-way switching valve 33 is provided between the outdoor heat exchanger 21 and the internal heat exchanger 23. Even when the flow direction of the outer flow path 25 of the internal heat exchanger 23 is reversed during the cooling operation and the heating operation, the flow direction of the inner flow path 24 is not reversed. To this end, the second end of the outdoor heat exchanger 21 is connected to the first port P1 of the third crossover valve 33, and the second port P2 of the third crossover valve 33 is internal heat exchanged. Connected to the third port P3 of the third four-way switching valve 33 via the inner flow passage 24 of the machine 23, and the fourth port P4 of the third four-way switching valve 33. Is connected to the first port P1 of the second four-way valve 32.

The third four-way valve 33 is a state in which the first port (P1) is in communication with the second port (P2) and the third port (P3) is in communication with the fourth port (P4) (in a solid line in Figure 1). State) and the first port P1 communicates with the third port P3 and the second port P2 communicates with the fourth port P4 (the state indicated by a dotted line in FIG. 1). .

The rest of the configuration is the same as in the sixth embodiment.

Operation operation

In the cooling operation, the first four-way switching valve 31, the second four-way switching valve 32, and the third four-way switching valve 33 are switched to the state shown by the solid line in FIG. The refrigerant discharged from the compressor 11 in this state is the first flow path switching valve 31, the outdoor heat exchanger 21, the third flow path switching valve 33, and the inner flow path 24 of the internal heat exchanger 23. , The third four-way valve 33, the second four-way valve 32, the expander 12, the second four-way valve 32, the outer flow path 25 of the internal heat exchanger 23, the indoor heat exchanger ( 22), the first four-way switching valve 31 flows in sequence, and is again sucked into the compressor (11).

In the internal heat exchanger (23), the refrigerant passing through the inner heat exchanger (24) after passing through the outdoor heat exchanger (21), and the refrigerant passing through the outer flow passage (25) before passing through the indoor heat exchanger (22) The supercritical refrigerant flows through the inner flow passage 24 and the low pressure refrigerant flows through the outer flow passage 25, so that the refrigerant flowing through the inner flow passage 24 and the outer flow passage 25 flow in the opposite directions. The flowing refrigerant is heat exchanged efficiently. As a result, the supercritical refrigerant is cooled in the internal heat exchanger 23 and flows into the expander 12 in a state where the cost is reduced.

In the heating operation, the first four-way switching valve 31, the second four-way switching valve 32, and the third four-way switching valve 33 is switched to the state shown by the dotted line in FIG. The refrigerant discharged from the compressor 11 in this state is the first four-way switching valve 31, the indoor heat exchanger 22, the outer flow passage 25 of the internal heat exchanger 23, the second four-way switching valve (32). , The expander 12, the second four-way switching valve 32, the third four-way switching valve 33, the inner passage 24 of the internal heat exchanger 23, the third four-way switching valve 33, the outdoor heat exchanger ( 21), the first four-way switching valve 31 flows in sequence, and is again sucked into the compressor (11).

In the internal heat exchanger (23), refrigerant passing through the inner heat exchanger (22) after passing through the indoor heat exchanger (22), and refrigerant passing through the inner flow path (24) after passing through the outdoor heat exchanger (21) The supercritical refrigerant flows through the outer flow passage 25 and the low pressure refrigerant flows through the inner flow passage 24, and the refrigerant flowing through the inner flow passage 24 and the outer flow passage 25 flow in the same direction. The flowing refrigerant is hardly heat exchanged. Thus, the refrigerant in the supercritical state flows into the expander 12 with almost no change in temperature even though it passes through the internal heat exchanger 23.

Effect of Eighth Embodiment

In this eighth embodiment, during the cooling operation, the low-pressure refrigerant before passing through the indoor heat exchanger 22 serving as the evaporator flows through the outer flow passage 25, and the refrigerant of the outer flow passage 25 and the inner flow passage 24 are used. Since the refrigerants of the flow paths flow in the opposite directions, the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are heat exchanged relatively efficiently, and the refrigerant in the supercritical state has a low temperature, resulting in a low cost. In the inflator 12. On the other hand, during the heating operation, the low pressure refrigerant before passing through the outdoor heat exchanger 21 serving as the evaporator flows through the inner passage 24, where the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are in the same direction. Since the refrigerant flows toward the outside, the refrigerant in the outer passage 25 and the refrigerant in the inner passage 24 are hardly heat exchanged, and the refrigerant in the supercritical state flows into the expander 12 with almost no change in temperature.

As described above, since the cost or flow rate can be adjusted by adjusting the temperature of the refrigerant flowing into the expander 12 during the cooling operation, the flow rates of the compressor 11 and the expander 12 are balanced, thereby lowering the COP. It becomes possible to prevent.

[Ninth Embodiment]

9th Embodiment is related with the air conditioner 1 comprised with the refrigeration apparatus which concerns on this invention. This air conditioner 1 is equipped with the refrigerant circuit 10 as shown in FIG. The refrigerant circuit 10 compresses the refrigerant into a supercritical state to execute a vapor compression refrigeration cycle. The air conditioner 1 of the ninth embodiment is configured to circulate the refrigerant in the refrigerant circuit 10 so as to switch between the cooling operation (cooling operation) and the heating operation (heating operation).

The refrigerant circuit 10 is charged with carbon dioxide (CO ₂ ) as a refrigerant. The refrigerant circuit 10 includes a compressor 11, an expander 12, an outdoor heat exchanger (heat source side heat exchanger) 21, an indoor heat exchanger (use side heat exchanger) 22, and an internal heat exchanger 23. , The first four-way switching valve 31, and the second four-way switching valve (32) is provided.

The compressor 11 and the expander 12 are each composed of a rotating piston fluid machine having a unique cylinder volume. The compressor 11 and the expander 12 are connected to each other by the rotation axis of the motor 13. The compressor 11 is rotationally driven by both the power (expansion power) obtained by the expansion of the refrigerant in the expander 12 and the power obtained by energizing the motor 13.

Since the compressor 11 and the expander 12 are connected to each other with a rotating shaft, the respective rotation speeds are always equal. Therefore, in the refrigerant circuit 10, the ratio Ve / Vc of the volume circulation amount Ve of the refrigerant passing through the expander 12 and the volume circulation amount Vc of the refrigerant passing through the compressor 11 is determined by the respective fluids. The fixed value is determined by the cylinder volume ratio of the machines 11 and 12. This cylinder volume ratio is the ratio of the said Ve / Vc and the density ratio of the inflow refrigerant density de of the expander 12 and the intake refrigerant density dc of the compressor 11 at the time of the heating of the air conditioner 1. It is designed so that de / dc is equal, that is, the mass flow rate Me of the refrigerant passing through the expander 12 and the mass flow rate Mc of the refrigerant passing through the compressor 11 are equal. .

Here, for the compressor 11 or the expander 12, the fluid machines constituting them are not limited to the rotary piston type, for example, the scroll type volumetric fluid machine may be used for the compressor 11 or the expander 12. You may use as.

The outdoor heat exchanger 21 is composed of a so-called cross fin fin tube type heat exchanger. The outdoor heat exchanger 21 is supplied with outdoor air by a fan outside the drawing. In this outdoor heat exchanger (21), heat exchange is performed between the supplied outdoor air and the refrigerant of the refrigerant circuit (10).

The indoor heat exchanger 22 is composed of a so-called cross fin fin tube heat exchanger. The indoor air is supplied to the indoor heat exchanger (22) by a fan outside the drawing. In this indoor heat exchanger (22), heat exchange is performed between the supplied indoor air and the refrigerant in the refrigerant circuit (10).

The internal heat exchanger 23 includes a first flow passage 27 and a second flow passage 28 disposed adjacent to each other, and a refrigerant flowing through the first flow passage 27 and a refrigerant flowing through the second flow passage 28. It is configured to be heat exchangeable. The internal heat exchanger (23) is configured such that, during the cooling operation, the high pressure refrigerant is exchanged with the low pressure refrigerant to be cooled.

During the cooling operation, the internal heat exchanger 23 is a counter flow in which the high pressure refrigerant flows through the first flow path 27 and the low pressure refrigerant flows in the opposite direction to the high pressure refrigerant in the second flow path 28. In the heating operation, both flow paths 24 and 25 are configured to be parallel flows through which the high pressure refrigerant flows in the same direction. In the cooling operation, the high pressure refrigerant after passing through the outdoor heat exchanger 21 serving as the radiator is cooled by heat exchange with the low pressure refrigerant before passing through the indoor heat exchanger 22 serving as the evaporator. On the other hand, at the time of heating operation, the high pressure refrigerant after passing through the indoor heat exchanger 22 which becomes a radiator flows through the 2nd flow path 28 and the 1st flow path 27 one by one, and cooling of a high pressure refrigerant is not performed.

In the refrigerant circuit 10, the discharge side of the compressor 11 is connected to the first port P1 of the first four-way switching valve 31, the second port P2 of the first four-way switching valve 31 is It is connected to the first end of the outdoor heat exchanger 21. The second end of the outdoor heat exchanger 21 is connected to the first port P1 of the second crossover valve 32, and the second port P2 of the second crossover valve 32 is an internal heat exchanger. It connects to the inflow side of the expander 12 via the 1st flow path 27 of 23. As shown in FIG. The outlet side of the inflator 12 is connected to the third port P3 of the second four-way valve 32, the fourth port P4 of the second four-way valve 32 is the first of the internal heat exchanger (23) It connects to the 1st end of the indoor heat exchanger 22 through the 2 flow path 28. As shown in FIG. The second end of the indoor heat exchanger 22 is connected to the third port P3 of the first four-way valve 31, and the fourth port P4 of the first four-way valve 31 is a compressor 11. It is connected to the suction side of the.

The first four-way valve 31, the first port (P1) is in communication with the second port (P2) and the third port (P3) in communication with the fourth port (P4) (in the solid line in Figure 10 State), and the first port P1 communicates with the third port P3 and the second port P2 communicates with the fourth port P4 (the state indicated by a dotted line in FIG. 10). .

In addition, the second four-way switching valve 32 has a state in which the first port P1 communicates with the second port P2 and the third port P3 communicates with the fourth port P4 (solid line in FIG. 10). State), and the first port P1 communicates with the third port P3 and the second port P2 communicates with the fourth port P4 (the state indicated by a dotted line in FIG. 10). do.

Operation operation

Next, the operation | movement at the time of cooling operation and the heating operation of this air conditioner 1 is demonstrated.

(Cooling operation)

In the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state shown by the solid line in FIG. 10. When the motor 13 is energized in this state, the refrigerant is circulated in the refrigerant circuit 10 to perform a freezing cycle. At this time, the outdoor heat exchanger 21 becomes a radiator, and the indoor heat exchanger 22 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. This high-pressure refrigerant flows into the outdoor heat exchanger 21 through the first four-way switching valve 31 as indicated by the solid arrow. In the outdoor heat exchanger (21), the high pressure refrigerant radiates heat to the outdoor air, thereby lowering the temperature.

The high pressure refrigerant flowing out from the outdoor heat exchanger 21 passes through the first flow path 27 of the internal heat exchanger 23 via the second cross switching valve 32. The high pressure refrigerant is cooled by heat exchange with the low pressure refrigerant flowing through the second flow path 28 in the internal heat exchanger 23. This high pressure refrigerant flows into the expander 12, and in the expander 12, the introduced high pressure refrigerant is expanded to convert the internal energy of the high pressure refrigerant into rotational power. By expansion in the expander 12, the high pressure refrigerant is reduced in pressure and changes from a supercritical state to a gas-liquid two-phase state.

The low pressure refrigerant flowing out of the expander 12 passes through the second flow path 28 of the indoor heat exchanger 22 through the second crossover switching valve 32, and at this time, the high pressure refrigerant flowing through the first flow path 27. It is heated by heat exchange with. The low pressure refrigerant flows into the indoor heat exchanger (22), and is endothermic from the indoor air in the indoor heat exchanger (22) to evaporate. In the indoor heat exchanger (22), indoor air is cooled by a low pressure refrigerant, and the cooled indoor air is returned to the room.

The low pressure refrigerant flowing out from the indoor heat exchanger (22) is sucked into the compressor (11) through the first crossover valve (31). The refrigerant sucked into the compressor 11 is compressed to a predetermined pressure and discharged from the compressor 11.

(Heating operation)

During the heating operation, the first four-way switching valve 31 and the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. When the motor 13 is energized in this state, the refrigerant is circulated in the refrigerant circuit 10 to perform a freezing cycle. At this time, the indoor heat exchanger 22 becomes a radiator, and the outdoor heat exchanger 21 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant, as in the cooling operation.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. The high pressure refrigerant flows into the indoor heat exchanger 22 through the first four-way switching valve 31, as indicated by the dotted arrow. In the indoor heat exchanger (22), the high pressure refrigerant radiates heat to the indoor air, whereby the temperature decreases. In the indoor heat exchanger (22), indoor air is heated by a high pressure refrigerant, and the heated indoor air is returned to the room.

The high pressure refrigerant flowing out from the indoor heat exchanger 22 passes through the second flow path 28 of the internal heat exchanger 23, and then, through the second four-way switching valve 32, the first of the internal heat exchanger 23. It passes through the flow path 27. At this time, in the internal heat exchanger 23, since the high-pressure refrigerant flowing out of the indoor heat exchanger 22 flows through the second flow path 28 and the first flow path 27 in sequence, no change in temperature occurs.

The high pressure refrigerant flowing out of the first passage 24 of the internal heat exchanger 23 flows into the expander 12. In the expander 12, the introduced high pressure refrigerant is expanded, and the internal energy of the high pressure refrigerant is converted into rotational power. By expansion in the expander 12, the high pressure refrigerant is reduced in pressure, and changes from a supercritical state to a gas-liquid two-phase state.

The low pressure refrigerant flowing out of the expander 12 flows into the outdoor heat exchanger 21 through the second four-way switching valve 32. In the outdoor heat exchanger (21), the low pressure refrigerant absorbs heat from the outdoor air and evaporates. The low pressure refrigerant flowing out from the outdoor heat exchanger 21 is sucked into the compressor 11 through the first four-way switching valve 31. The refrigerant sucked into the compressor 11 is compressed to a predetermined pressure and discharged from the compressor 11.

Effect of the ninth embodiment

In the ninth embodiment, in the internal heat exchanger (23), during the cooling operation, the high-pressure refrigerant after passing through the outdoor heat exchanger (21), which becomes a radiator, flows through the first flow path (27), and becomes an evaporator. Since the low pressure refrigerant before passing through the 22 flows through the second flow path 28, the high pressure refrigerant is cooled. On the other hand, at the time of heating operation, since the high pressure refrigerant after passing through the indoor heat exchanger 22 which becomes a radiator flows through the 2nd flow path 28 and the 1st flow path 27 sequentially, the temperature of a high pressure refrigerant does not change.

As described above, since the internal heat exchanger 23 functions only during the cooling operation, the high pressure refrigerant sucked into the expander 12 can be cooled during the cooling operation, thereby increasing the inflow refrigerant density de of the expander 12. Can be. As a result, in the conventional refrigeration apparatus cooling operation, the refrigerant mass flow rate Mc of the compressor 11 becomes larger than the refrigerant mass flow rate Me of the expander 12 for the reasons described above. In this case, since the refrigerant mass flow rate Me of the expander 12 can be increased, the refrigerant mass flow rates Mc and Me of both can be balanced.

In the ninth embodiment, the refrigerant mass flow rates Mc and Me are balanced without bypassing the expander 12 with a portion of the refrigerant. As a result, when a part of the refrigerant is diverted from the expander 12, the expansion power of the expander 12 decreases and the COP also decreases. In the present embodiment, since all the refrigerant can be introduced into the expander 12, the COP decreases. Can be avoided.

In the ninth embodiment, the high-pressure refrigerant and the low-pressure refrigerant flow in the reverse direction through the internal heat exchanger 23 during the cooling operation to increase the heat exchange efficiency, but the low-pressure refrigerant is the liquid refrigerant before evaporation and the heat transfer rate is high. Since the high pressure refrigerant and the low pressure refrigerant are high, the internal heat exchanger 23 may flow in the same direction. Even in this case, it is possible to cool the high pressure refrigerant.

Modification Example of Ninth Embodiment

(First modification)

In the first modification of the ninth embodiment, the receiver 41 is provided between the expander 12 and the second four-way switching valve 32 in the refrigerant circuit 10 of the ninth embodiment. In other words, this first modification is provided with the receiver 41 on the outlet side of the inflator 12.

As shown in FIG. 11, the outlet side of the expander 12 is connected to the inlet port of the receiver 41, and the outlet port of the receiver 41 is connected to the third port P3 of the second four-way switching valve 32. do. Further, a liquid injection pipe 42 connected to the lower end of the receiver 41 and a gas discharge pipe 43 connected to the upper portion of the receiver 41 are connected to the suction side of the compressor 11. The first electric valve EV1 is provided in the liquid injection pipe 42, and the second electric valve EV2 is provided in the gas discharge pipe 43, and the flow rate of the refrigerant can be adjusted.

The other structure is the same as that of 9th Embodiment of FIG.

In the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state indicated by solid lines in FIG. 11. The refrigerant discharged from the compressor 11 in this state is the first flow path 27 of the first cross switching valve 31, the outdoor heat exchanger 21, the second cross switching valve 32, and the internal heat exchanger 23. ), Expander 12, receiver 41, second crossover valve 32, second flow path 28 of the internal heat exchanger 23, indoor heat exchanger 22, the first four-way valve (31) ) Is sequentially flowed back into the compressor (11).

In the internal heat exchanger (23), the high pressure refrigerant after passing through the outdoor heat exchanger (21) flows through the first flow passage (27), and the low pressure refrigerant before passing through the indoor heat exchanger (22) passes through the second flow passage (28). As a result, the high pressure refrigerant and the low pressure refrigerant are heat exchanged. As a result, the high pressure refrigerant is cooled in the internal heat exchanger 23 and then flows into the expander 12.

In this cooling operation, the suction superheat control and the oil recovery operation of the compressor 11 can be performed by adjusting the opening degree of the first electric valve EV1 of the liquid injection pipe 42. Moreover, the gas discharge of the receiver 41 can also be performed by adjusting the opening degree of the 2nd electric valve EV2 of the gas discharge pipe 43. Further, when the opening degree of the first electric valve EV1 of the liquid injection pipe 42 and the second electric valve EV2 of the gas discharge pipe 43 is adjusted, when the capacity shortage occurs in the compressor 11 during operation, The lack of capacity can be compensated for.

In the heating operation, the first four-way switching valve 31, the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. The refrigerant discharged from the compressor 11 in this state is the first flow path switching valve 31, the indoor heat exchanger 22, the second flow path 28 of the internal heat exchanger 23, and the second flow path switching valve 32. ), The first flow path 27 of the internal heat exchanger 23, the expander 12, the receiver 41, the second four-way switching valve 32, the outdoor heat exchanger 21, the first four-way switching valve (31) ) Is sequentially flowed back into the compressor (11).

In the internal heat exchanger (23), since the high pressure refrigerant after passing through the indoor heat exchanger (22) serving as a radiator flows through the second flow path (28) and the first flow path (27) in turn, the temperature of the high pressure refrigerant does not change. not. As a result, the high pressure refrigerant is introduced into the expander 12 without being cooled.

Also in this modification, since the internal heat exchanger 23 functions only in the cooling operation, the high pressure refrigerant sucked into the expander 12 can be cooled during the cooling operation, and the inflow refrigerant density de of the expander 12 is reduced. Can be increased. As a result, in the conventional refrigeration apparatus cooling operation, the refrigerant mass flow rate Mc of the compressor 11 becomes larger than the refrigerant mass flow rate Me of the expander 12 for the reasons described above. In the first modification, since the refrigerant mass flow rate Me of the expander 12 can be increased, the refrigerant mass flow rates Mc and Me of both can be balanced.

In addition, as in the ninth embodiment, since the refrigerant mass flow rates Mc and Me are balanced without bypassing the inflator 12, a portion of the refrigerant is introduced, so that all the refrigerant is introduced into the expander 12, thereby reducing the COP. It is also possible to avoid it.

(Second modification)

In the second modification of the ninth embodiment, the bridge circuit 32a is used instead of the second four-way switching valve 32 in the refrigerant circuit 10 of the ninth embodiment.

As shown in Fig. 12, the bridge circuit 32a is formed by connecting four conduits in a bridge shape, and has four ports P1, P2, P3, and P4. Each of the four pipelines is provided with a check valve (CV). The check valve CV includes a refrigerant flow from the first port P1 to the second port P2, a refrigerant flow from the third port P3 to the fourth port P4, and a third port ( It is installed in each conduit to allow the refrigerant flow from P3 to the first port P1 and the refrigerant flow from the fourth port P4 to the second port P2.

The second end of the outdoor heat exchanger 21 is connected to the first port P1 of the bridge circuit 32a. The second port P2 of the bridge circuit 32a is connected to the inflow side of the expander 12 via the first flow path 27 of the internal heat exchanger 23. The outflow side of the expander 12 is connected to the third port P3 of the bridge circuit 32a. The fourth port P4 of the bridge circuit 32a is connected to the first end of the indoor heat exchanger 22 via the second flow path 28 of the internal heat exchanger 23.

The other structure is the same as that of 9th Embodiment of FIG.

During the cooling operation, the first four-way switching valve 31 is switched to the state shown by the solid line in FIG. The refrigerant discharged from the compressor (11) in this state is the first flow path switching valve (31), the outdoor heat exchanger (21), the bridge circuit (32a), the first flow path (27) of the internal heat exchanger (23), the expander 12, the bridge circuit 32a, the second flow path 28 of the internal heat exchanger 23, the indoor heat exchanger 22, and the first four-way switching valve 31 are sequentially flown, and are again sucked into the compressor 11. do.

In the internal heat exchanger (23), the high pressure refrigerant after passing through the outdoor heat exchanger (21) flows through the first flow passage (27), and the low pressure refrigerant before passing through the indoor heat exchanger (22) passes through the second flow passage (28). As a result, the high pressure refrigerant and the low pressure refrigerant are heat exchanged. As a result, the high pressure refrigerant is cooled in the internal heat exchanger 23 and then introduced into the expander 12.

During the heating operation, the first four-way switching valve 31 is switched to the state shown by the dotted line in FIG. The refrigerant discharged from the compressor 11 in this state is the first cross-over valve 31, the indoor heat exchanger 22, the second flow path 28 of the internal heat exchanger 23, the bridge circuit 32a, and the interior. The first flow path 27 of the heat exchanger 23, the expander 12, the bridge circuit 32a, the outdoor heat exchanger 21, and the first four-way switching valve 31 are sequentially flowed into the compressor 11. do.

In the internal heat exchanger (23), since the high pressure refrigerant after passing through the indoor heat exchanger (22) serving as a radiator flows through the second flow path (28) and the first flow path (27) in turn, the temperature of the high pressure refrigerant does not change. not. As a result, the high pressure refrigerant is introduced into the expander 12 without being cooled.

Also in this modification, since the internal heat exchanger 23 functions only in the cooling operation, the high pressure refrigerant sucked into the expander 12 can be cooled during the cooling operation, thereby increasing the inflow refrigerant density de of the expander 12. You can. As a result, in the conventional refrigeration apparatus cooling operation, the refrigerant mass flow rate Mc of the compressor 11 becomes larger than the refrigerant mass flow rate Me of the expander 12 for the reasons described above. In the second modification, since the refrigerant mass flow rate Me of the expander 12 can be increased, both refrigerant mass flow rates Mc and Me can be balanced.

In addition, as in the ninth embodiment, since the refrigerant mass flow rates Mc and Me are balanced without bypassing the inflator 12, a portion of the refrigerant is introduced, so that all the refrigerant is introduced into the expander 12, thereby reducing the COP. It is also possible to avoid it.

[Tenth Embodiment]

As shown in FIG. 13, the 10th embodiment differs in the configuration of the refrigerant circuit 10 from the ninth embodiment. In this example, the position of the internal heat exchanger 23 is different from that of the ninth embodiment, and a bypass passage 45 is provided for the high pressure refrigerant to bypass the internal heat exchanger 23 during the heating operation.

In this refrigerant circuit 10, the discharge side of the compressor 11 is connected to the first port P1 of the first four-way switching valve 31, and the second port P2 of the first four-way switching valve 31 is connected. It is connected to the first end of the outdoor heat exchanger 21. The second end of the outdoor heat exchanger 21 is connected to the first port P1 of the second four-way valve 32, and the second port P2 of the second four-way valve 32 is an internal heat exchanger ( It connects to the inflow side of the expander 12 via the 1st flow path 27 of 23. As shown in FIG.

The first opening / closing valve SV1 is installed between the second port P2 of the second four-way switching valve 32 and the first flow path 27 of the internal heat exchanger 23. One end of the bypass passage 45 having the second on-off valve SV2 is connected to the pipe between the second port P2 of the second cross-over valve 32 and the first on-off valve SV1. The other end of the bypass passage 45 joins the pipe connecting the first flow path 27 of the internal heat exchanger 23 and the inflow side of the expander 12.

The outlet side of the inflator 12 is connected to the third port P3 of the second four-way valve 32, the fourth port P4 of the second four-way valve 32 is the first of the indoor heat exchanger 22 1 is connected to the end. The second end of the indoor heat exchanger 22 is connected to the third port P3 of the first four-way valve 31, and the fourth port P4 of the first four-way valve 31 is an internal heat exchanger ( It is connected to the suction side of the compressor 11 via the 2nd flow path 28 of 23.

With the above structure, the internal heat exchanger 23 is configured such that the high pressure refrigerant flows through the first flow path 27 while the low pressure refrigerant flows through the second flow path 28 during the cooling operation. In the cooling operation, the high pressure refrigerant after passing through the outdoor heat exchanger 21 is cooled by heat exchange with the low pressure refrigerant after passing through the indoor heat exchanger 22.

In this configuration, as the first open / close valve SV1 and the second open / close valve SV2, an electromagnetic open / close valve or an electric valve can be used. Moreover, you may provide the 1st switching valve SV1 in the front and back of the internal heat exchanger 23. As shown in FIG.

Operation operation

In the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state shown by the solid line in FIG. In addition, the first on-off valve SV1 is opened and the second on-off valve SV2 is closed. The refrigerant discharged from the compressor 11 in this state is the first flow path 27 of the first cross switching valve 31, the outdoor heat exchanger 21, the second cross switching valve 32, and the internal heat exchanger 23. ), The expander 12, the second crossover valve 32, the indoor heat exchanger 22, the first crossover valve 31, and the second flow path 28 of the internal heat exchanger 23 are sequentially flowed again. It is sucked into the compressor (11).

In the internal heat exchanger (23), the high pressure refrigerant after passing through the outdoor heat exchanger (21) flows through the first flow path (27), and the low pressure refrigerant after passing through the indoor heat exchanger (22) is the second flow path (28). ), These high pressure refrigerants and low pressure refrigerants are heat exchanged. As a result, the high pressure refrigerant is cooled in the internal heat exchanger 23 and then introduced into the expander 12.

In the heating operation, the first four-way switching valve 31 and the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. In addition, the first on-off valve SV1 is closed and the second on-off valve SV2 is opened. The refrigerant discharged from the compressor 11 in this state is the first four-way switching valve 31, the indoor heat exchanger 22, the second four-way switching valve 32, the bypass passage 45, the expander 12, The second flow path switching valve 32, the outdoor heat exchanger 21, the first flow path switching valve 31, and the second flow path 28 of the internal heat exchanger 23 are sequentially flowed into the compressor 11. .

In the internal heat exchanger 23, the high pressure refrigerant after passing through the indoor heat exchanger 22 does not flow, and only the low pressure refrigerant after passing through the outdoor heat exchanger 21 flows through the second flow path 28. The temperature of the refrigerant does not change. As a result, the high pressure refrigerant is introduced into the expander 12 without being cooled.

Effect of the tenth embodiment

Also in this tenth embodiment, since the internal heat exchanger 23 functions only in the cooling operation, the high-pressure refrigerant sucked into the expander 12 can be cooled during the cooling operation, and the inflow refrigerant density de of the expander 12 can be cooled. Can be increased. As a result, in the conventional refrigerator cooling operation, the refrigerant mass flow rate Mc of the compressor 11 becomes larger than the refrigerant mass flow rate Me of the expander 12, whereas the refrigerant mass flow rate Me of the expander 12 is increased. Since can be increased, the mass flow rates (Mc, Me) of the refrigerants can be balanced.

In addition, similarly to the ninth embodiment, since the refrigerant mass flow rates Mc and Me are balanced without bypassing the inflator 12, a portion of the refrigerant is introduced, so that all the refrigerant is introduced into the expander 12, thereby reducing the COP. It is also possible to avoid.

Modification of the tenth embodiment

(First modification)

In the first modification of the tenth embodiment, the receiver 41 is provided between the outlet side of the evaporator and the low pressure side of the internal heat exchanger 23 in the refrigerant circuit 10 of the tenth embodiment shown in FIG. 13. will be.

As shown in FIG. 14, the fourth port P4 of the first four-way switching valve 31 is connected to an inlet of the receiver 41, and an outlet of the receiver 41 is formed of the internal heat exchanger 23. It is connected to the suction side of the compressor 11 via two flow paths 28. Moreover, the liquid injection pipe 42 connected to the lower end part of the receiver 41 is connected to the suction side of the compressor 11. The liquid injection pipe 42 is provided with a first electric valve EV1 so that the flow rate of the refrigerant can be adjusted.

Here, in this example, since the outlet side of the receiver 41 is in a saturated gas state, the internal heat exchanger 23 is configured such that the high pressure refrigerant and the low pressure refrigerant flow in opposite directions to each other during the cooling operation.

The other structure is the same as that of 10th Embodiment of FIG.

During the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state shown by the solid line in FIG. In addition, the first on-off valve SV1 is opened and the second on-off valve SV2 is closed. The refrigerant discharged from the compressor 11 in this state is the first flow path 27 of the first cross switching valve 31, the outdoor heat exchanger 21, the second cross switching valve 32, and the internal heat exchanger 23. ), Expander 12, second crossover valve 32, indoor heat exchanger 22, first crossover valve 31, receiver 41, the second flow path (28) of the internal heat exchanger (23) ) Is sequentially flowed back into the compressor (11).

In the internal heat exchanger (23), the high pressure refrigerant after passing through the outdoor heat exchanger (21) flows through the first flow path (27), and the low pressure refrigerant after passing through the indoor heat exchanger (22) and the receiver (41). Since the second flow path 28 flows, these high pressure refrigerants and low pressure refrigerants are heat exchanged. As a result, the high pressure refrigerant is cooled in the internal heat exchanger 23 and then introduced into the expander 12.

During the heating operation, the first four-way switching valve 31, the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. In addition, the first on-off valve SV1 is closed and the second on-off valve SV2 is opened. The refrigerant discharged from the compressor 11 in this state is the first four-way switching valve 31, the indoor heat exchanger 22, the second four-way switching valve 32, the bypass passage 45, the expander 12, The second crossover valve 32, the outdoor heat exchanger 21, the first crossover valve 31, the receiver 41, and the second flow path 28 of the internal heat exchanger 23 sequentially flow, and again the compressor. Inhaled by (11).

In the internal heat exchanger 23, the high pressure refrigerant after passing through the indoor heat exchanger 22 does not flow, and only the low pressure refrigerant after passing through the outdoor heat exchanger 21 and the receiver 41 passes through the second flow path 28. ), The temperature of the high-pressure refrigerant does not change. As a result, the high pressure refrigerant is introduced into the expander 12 without being cooled.

Also in this modification, since the internal heat exchanger 23 functions only during the cooling operation, the high pressure refrigerant sucked into the expander 12 can be cooled at the time of cooling operation, and the inflow refrigerant density of the expander 12 (de ) Can be increased. As a result, in the conventional refrigerator cooling operation, the refrigerant mass flow rate Mc of the compressor 11 becomes larger than the refrigerant mass flow rate Me of the expander 12, whereas the refrigerant mass flow rate Me of the expander 12 is increased. ) Can be increased, so that the refrigerant mass flow rates (Mc, Me) of both can be balanced.

In addition, as in the ninth embodiment, since the refrigerant mass flow rates Mc and Me are balanced without bypassing the inflator 12, a portion of the refrigerant is introduced, so that all the refrigerant is introduced into the expander 12, thereby reducing the COP. It is also possible to avoid it.

(Second modification)

The second modification of the tenth embodiment is an example in which the configuration in which the refrigerant bypasses the internal heat exchanger 23 in the refrigerant circuit 10 of the tenth embodiment shown in FIG. 13 is changed.

As shown in FIG. 15, in the refrigerant circuit 10, the first switching valve SV1 is not installed between the second four-way switching valve 32 and the first heat exchanger 27 of the internal heat exchanger 23, and heating is performed. The bypass passage (high pressure side bypass passage) 45 of FIG. 13 for bypassing the coolant 27 during operation is also not provided.

The first on-off valve SV1 is provided between the fourth port P4 of the first four-way switching valve 31 and the second flow path 28 of the internal heat exchanger 23. In addition, a bypass passage (low pressure side bypass passage) having a second on-off valve SV2 is provided in the pipe between the fourth port P4 of the first cross-over valve 31 and the first on-off valve SV1. One end of) is connected. The other end of the bypass passage 46 joins the pipe connecting the second flow path 28 of the internal heat exchanger 23 and the suction side of the compressor 11.

The other structure is the same as that of 10th Embodiment of FIG.

In the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state indicated by solid lines in FIG. 15. In addition, the first on-off valve SV1 is opened and the second on-off valve SV2 is closed. The refrigerant discharged from the compressor 11 in this state is the first flow path 27 of the first cross switching valve 31, the outdoor heat exchanger 21, the second cross switching valve 32, and the internal heat exchanger 23. ), The expander 12, the second crossover valve 32, the indoor heat exchanger 22, the first crossover valve 31, and the second flow path 28 of the internal heat exchanger 23 are sequentially flowed again. It is sucked into the compressor (11).

In the internal heat exchanger 23, the high pressure refrigerant after passing through the outdoor heat exchanger 21 flows through the first flow path 27, and the low pressure refrigerant after passing through the indoor heat exchanger 22 passes through the second flow path 28. As a result, the high pressure refrigerant and the low pressure refrigerant are heat exchanged. As a result, the high pressure refrigerant is cooled in the internal heat exchanger 23 and then introduced into the expander 12.

During the heating operation, the first four-way switching valve 31 and the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. The first on-off valve SV1 is closed and the second on-off valve SV2 is opened. The refrigerant discharged from the compressor 11 in this state is the first flow path 27 of the first cross switching valve 31, the indoor heat exchanger 22, the second cross switching valve 32, and the internal heat exchanger 23. ), The inflator 12, the second four-way switching valve 32, the outdoor heat exchanger 21, the first four-way switching valve 31, and the bypass passage 46, are sequentially sucked into the compressor 11. .

In the internal heat exchanger (23), the high pressure refrigerant after passing through the indoor heat exchanger (22) flows through the first flow path (27), but the low pressure refrigerant after passing through the outdoor heat exchanger (21) does not flow. The temperature does not change. As a result, the high pressure refrigerant is introduced into the expander 12 without being cooled.

Also in the second modification of the tenth embodiment, since the internal heat exchanger 23 functions only in the cooling operation, the high pressure refrigerant sucked into the expander 12 can be cooled during the cooling operation, thereby expanding the expander 12. The inflow refrigerant density (de) of can be increased. As a result, in the conventional refrigerator cooling operation, the refrigerant mass flow rate Mc of the compressor 11 becomes larger than the refrigerant mass flow rate Me of the expander 12, whereas the refrigerant mass flow rate Me of the expander 12 is increased. ) Can be increased, so that the refrigerant mass flow rates (Mc, Me) of both can be balanced.

In addition, as in the ninth embodiment, since the refrigerant mass flow rates Mc and Me are balanced without bypassing the inflator 12, a portion of the refrigerant is introduced, so that all the refrigerant is introduced into the expander 12, thereby reducing the COP. It is also possible to avoid it.

(Third modification)

The third modification of the tenth embodiment is an example in which the second four-way switching valve 32 is not used in the refrigerant circuit of the tenth embodiment shown in FIG. 13.

As shown in FIG. 16, in the refrigerant circuit 10, the second end of the outdoor heat exchanger 21 is interposed between the third check valve CV3 and the first flow path 27 of the internal heat exchanger 23. It is connected to the inflow side of the expander 12. The outlet side of the expander 12 is divided into two, one side is connected to the pipe between the outdoor heat exchanger 21 and the third check valve CV3 via the first check valve CV1, and the other is connected to the second. It is connected to the 1st end of the indoor heat exchanger 22 via the check valve CV2. One end of the bypass passage 45 having the fourth check valve CV4 is connected to the pipe between the second check valve CV2 and the indoor heat exchanger 22, and the other end of the bypass passage 45 is connected. Silver joins a pipe that connects the first flow path 27 of the internal heat exchanger 23 and the inflow side of the expander 12.

Here, the first check valve CV1 and the second check valve CV2 are valves which allow the refrigerant to flow out from the expander 12, and instead of the cooling operation and the heating operation by using an electromagnetic switching valve or the like. The switching state may be switched on. The third check valve CV3 and the fourth check valve CV4 are valves that allow the refrigerant to flow out from the expander 12 and, like the first check valve CV1 and the second check valve CV2, are electromagnetically closed. You may substitute by a valve etc.

The other structure is the same as that of 10th embodiment shown in FIG.

Operation operation

During the cooling operation, the first four-way switching valve 31 is switched to the state shown by the solid line in FIG. The refrigerant discharged from the compressor 11 in this state is the first flow path 27 of the first four-way switching valve 31, the outdoor heat exchanger 21, the third check valve CV3, and the internal heat exchanger 23. , The expander 12, the second check valve CV2, the indoor heat exchanger 22, the first four-way switching valve 31, and the second flow path 28 of the internal heat exchanger 23, and then the compressor ( 11) is inhaled.

In the internal heat exchanger 23, the high pressure refrigerant after passing through the outdoor heat exchanger 21 flows through the first flow path 27, and the low pressure refrigerant after passing through the indoor heat exchanger 22 passes through the second flow path 28. As a result, the high pressure refrigerant and the low pressure refrigerant are heat exchanged. As a result, the high pressure refrigerant is cooled in the internal heat exchanger 23 and then introduced into the expander 12.

In the heating operation, the first four-way switching valve 31 is switched to the state shown by the dotted line in FIG. In this state, the refrigerant discharged from the compressor 11 includes the first four-way switching valve 31, the indoor heat exchanger 22, the bypass passage 45 (fourth check valve CV4), the expander 12, The first check valve CV1, the outdoor heat exchanger 21, the first four-way switching valve 31, and the second flow path 28 of the internal heat exchanger 23 are sequentially flowed into the compressor 11.

In the internal heat exchanger 23, the high pressure refrigerant after passing through the indoor heat exchanger 22 does not flow, and only the low pressure refrigerant after passing through the outdoor heat exchanger 21 flows through the second flow path 28. The temperature of the refrigerant does not change. As a result, the high pressure refrigerant is introduced into the expander 12 without being cooled.

Also in this modified example, since the internal heat exchanger 23 functions only in the cooling operation, the high pressure refrigerant sucked into the expander 12 can be cooled during the cooling operation, so that the inflow refrigerant density de of the expander 12 is reduced. You can increase it. As a result, in the conventional refrigerator cooling operation, the refrigerant mass flow rate Mc of the compressor 11 becomes larger than the refrigerant mass flow rate Me of the expander 12, whereas the refrigerant mass flow rate Me of the expander 12 is increased. ) Can be increased, so that the refrigerant mass flow rates (Mc, Me) of both can be balanced.

In addition, as in the ninth embodiment, since the refrigerant mass flow rates Mc and Me are balanced without bypassing the inflator 12, a portion of the refrigerant is introduced, so that all the refrigerant is introduced into the expander 12, thereby reducing the COP. It is also possible to avoid it.

(Fourth modification)

The fourth modification of the tenth embodiment is an example in which the internal heat exchanger 23 causes the high pressure refrigerant to flow in the opposite direction to the low pressure refrigerant during the cooling operation in the refrigerant circuit of the tenth embodiment shown in FIG. 13. .

As shown in FIG. 17, the second port P2 of the second four-way switching valve 32 is opposite to the example of FIG. 13 in the first flow path 27 of the internal heat exchanger 23. Is connected to. Moreover, in the 1st flow path 27 of the internal heat exchanger 23, the left end part in figure is connected to the inflow side of the expander 12 via the 1st opening / closing valve SV1. The bypass passage 45 having the second on-off valve SV2 includes a pipe between the second port P2 of the second crossover valve 32 and the internal heat exchanger 23, and a first on-off valve ( It is connected to the pipe between SV1) and the expander 12.

The other structure is the same as that of 10th embodiment shown in FIG.

In this modification, the same effects as those of the tenth embodiment of FIG. 13 can be obtained, and the high pressure refrigerant and the low pressure refrigerant flow in the opposite directions in the internal heat exchanger 23 during the cooling operation. It becomes possible to cool effectively.

[Eleventh Embodiment]

As shown in FIG. 18, 11th Embodiment differs in the structure of the refrigerant circuit 10 from 9th and 10th Embodiment.

In this refrigerant circuit 10, the discharge side of the compressor 11 is connected to the first port P1 of the first four-way switching valve 31, and the second port P2 of the first four-way switching valve 31 is connected. It is connected to the first end of the outdoor heat exchanger 21. The second end of the outdoor heat exchanger 21 is connected to the first port P1 of the second crossover valve 32, and the second port P2 of the second crossover valve 32 is an internal heat exchanger. It connects to the inflow side of the expander 12 via the 1st flow path 27 of 23. As shown in FIG.

The outlet side of the inflator 12 is connected to the third port P3 of the first four-way valve 31, and the fourth port P4 of the first four-way valve 31 is connected to the first port of the indoor heat exchanger 22. 1 is connected to the end. The second end of the indoor heat exchanger 22 is connected to the third port P3 of the second four-way valve 32, and the fourth port P4 of the second four-way switch 32 is an internal heat exchanger ( It is connected to the suction side of the compressor 11 via the 2nd flow path 28 of 23.

A first opening / closing valve SV1 is provided between the second flow path 28 of the internal heat exchanger 23 and the suction side of the compressor 11. The pipe between the fourth port P4 of the second four-way valve 32 and the second flow path 28 of the internal heat exchanger 23 and between the first opening / closing valve SV1 and the suction side of the compressor 11 is provided. The bypass passage 46 having the second open / close valve SV2 is connected to the pipe.

With the above structure, the internal heat exchanger 23 is configured such that the high pressure refrigerant flows through the first flow path 27 while the low pressure refrigerant flows through the second flow path 28 during the cooling operation. In the cooling operation, the high pressure refrigerant after passing through the outdoor heat exchanger 21 is cooled by heat exchange with the low pressure refrigerant after passing through the indoor heat exchanger 22.

Each of the first four-way switching valve 31 and the second four-way switching valve 32 has a first port P1 communicating with a second port P2 and a third port P3 with a fourth port P4. And a state in which the first port P1 communicates with the fourth port P4 and the second port P2 communicates with the third port P3 (FIG. 18). (Indicated by a dotted line at 18).

Also in this eleventh embodiment, a receiver may be provided between the outlet side of the expander 12 or between the evaporator and the low pressure side of the internal heat exchanger 23, and the high pressure side bypass passage instead of the low pressure side bypass passage 46. 45 may be provided and the high pressure refrigerant and the low pressure refrigerant flow at the time of cooling operation in the internal heat exchanger 23 may be the counter flow.

Operation operation

In the cooling operation, the first four-way switching valve 31 and the second four-way switching valve 32 are switched to the state shown by the solid line in FIG. In addition, the first on-off valve SV1 is opened and the second on-off valve SV2 is closed. The refrigerant discharged from the compressor 11 in this state is the first flow path 27 of the first cross switching valve 31, the outdoor heat exchanger 21, the second cross switching valve 32, and the internal heat exchanger 23. ), The expander 12, the first four-way switching valve 31, the indoor heat exchanger 22, the second four-way switching valve 32, the second flow path 28 of the internal heat exchanger 23, and then again. It is sucked into the compressor (11).

In the internal heat exchanger 23, the high pressure refrigerant after passing through the outdoor heat exchanger 21 flows through the first flow path 27, and the low pressure refrigerant after passing through the indoor heat exchanger 22 passes through the second flow path 28. As a result, the high pressure refrigerant and the low pressure refrigerant are heat exchanged. As a result, the high pressure refrigerant is cooled in the internal heat exchanger 23 and then introduced into the expander 12.

In the heating operation, the first four-way switching valve 31 and the second four-way switching valve 32 is switched to the state shown by the dotted line in FIG. The first on-off valve SV1 is closed and the second on-off valve SV2 is opened. The refrigerant discharged from the compressor 11 in this state is the first flow path 27 of the first cross switching valve 31, the indoor heat exchanger 22, the second cross switching valve 32, and the internal heat exchanger 23. ), The inflator 12, the first four-way switching valve 31, the outdoor heat exchanger 21, the second four-way switching valve 32, and the bypass passage 46, are sequentially sucked into the compressor 11. .

In the internal heat exchanger 23, the high pressure refrigerant after passing through the indoor heat exchanger 22 flows through the first flow path 27, but the low pressure refrigerant after passing through the outdoor heat exchanger 21 passes through the second flow path 28. ), The temperature of the high pressure refrigerant does not change. As a result, the high pressure refrigerant is introduced into the expander 12 without being cooled.

Effect of the eleventh embodiment

Also in this eleventh embodiment, since the internal heat exchanger 23 functions only during the cooling operation, the high-pressure refrigerant sucked into the expander 12 can be cooled during the cooling operation, and the inflow refrigerant density de of the expander 12 can be cooled. Can be increased. As a result, in the conventional refrigerator cooling operation, the refrigerant mass flow rate Mc of the compressor 11 becomes larger than the refrigerant mass flow rate Me of the expander 12, whereas the refrigerant mass flow rate Me of the expander 12 is increased. ) Can be increased, so that the refrigerant mass flow rates (Mc, Me) of both can be balanced.

In addition, as in the ninth embodiment, since the refrigerant mass flow rates Mc and Me are balanced without bypassing the inflator 12, a portion of the refrigerant is introduced, so that all the refrigerant is introduced into the expander 12, thereby reducing the COP. It is also possible to avoid it.

[Twelfth Embodiment]

The refrigerating device of the twelfth embodiment is applied to the air conditioner (1). The air conditioner 1 is configured to switch between the indoor cooling operation and the heating operation.

As shown in FIG. 19, the air conditioner 1 includes a refrigerant circuit 10. In the refrigerant circuit 10, the refrigerant is circulated to achieve a vapor compression refrigeration cycle. The refrigerant circuit 10 is filled with carbon dioxide (CO ₂ ) as a refrigerant.

In addition, the refrigerant circuit 10 includes a compressor 11, an expander 12, an outdoor heat exchanger 21, an indoor heat exchanger 22, a gas-liquid separator 51, a first cross-over valve 31, and a second. The four way switching valve 32 is connected.

The compressor 11 and the expander 12 are each composed of a rotating piston fluid machine having a unique cylinder volume. The compressor 11 and the expander 12 are connected to each other by the rotation axis of the motor 13. The compressor 11 is rotationally driven by both the power (expansion power) obtained by expansion of the refrigerant in the expander 12 and the power obtained by energizing the motor 13. At this time, since the compressor 11 and the expander 12 are connected to each other and the rotation shaft, the respective rotation speed is always equal. Therefore, in the refrigerant circuit 10, the ratio Ve / Vc of the volume circulation amount Ve of the refrigerant passing through the expander 12 and the volume circulation amount Vc of the refrigerant passing through the compressor 11 is determined by the respective fluids. The fixed value is determined by the cylinder volume ratio of the machines 11 and 12. The cylinder volume ratio is the ratio of Ve / Vc and the density ratio de of the intake refrigerant density de of the expander 12 and the intake refrigerant density dc of the compressor 11 during the heating of the air conditioner 1 (de). / dc) is designed to be equivalent, that is, the mass flow rate Me of the refrigerant passing through the expander 12 and the mass flow rate Mc of the refrigerant passing through the compressor 11 are equal.

The outdoor heat exchanger 21 and the indoor heat exchanger 22 are composed of a so-called cross fin fin tube type heat exchanger. Outdoor air is sent to the outdoor heat exchanger 21 by a fan outside the drawing. In this outdoor heat exchanger (21), heat exchange is performed between outdoor air and a refrigerant. On the other hand, indoor air is sent to the indoor heat exchanger (22) by a fan outside the drawing. In this indoor heat exchanger (22), heat exchange is performed between the indoor air and the refrigerant.

The gas-liquid separator 51 is connected to the discharge side of the expander 12. The gas-liquid separator 51 is a hermetically sealed container that separates the refrigerant in the two-phase state expanded by the expander 12 into a liquid refrigerant and a gas refrigerant. Inside the gas-liquid separator 51, a liquid reservoir 52 in which the separated liquid refrigerant is stored is formed in the lower space, and a gas reservoir 53 in which the separated gas refrigerant is stored is formed in the upper space.

The separation liquid pipe 54 is connected to the liquid storage part 52 of the gas liquid separator 51, while the separation gas pipe 55 is connected to the gas liquid gas storage part 53. The separation liquid pipe 54 is a pipe for sending the liquid refrigerant separated by the gas-liquid separator 51 to the second four-way switching valve 32. The separation gas pipe 55 is a so-called gas injection pipe (first injection pipe) that sends the gas refrigerant separated by the gas-liquid separator 51 to the suction side of the compressor 11. The separation gas pipe 55 is provided with a gas control valve 38 for adjusting the flow rate of the gas refrigerant sent to the suction side of the compressor 11.

Moreover, the gas-liquid separator 51 is provided with the heat-transfer tube 50 which penetrates the inside of this gas-liquid separator 51 so that it may be adjacent to the liquid storage part 52. FIG. One end of the heat transfer pipe 50 is connected to one end of the outdoor heat exchanger 21, and the other end is connected to the second cross switching valve 32. And the heat exchanger tube 50 comprises the liquid refrigerant in the liquid storage part 52, and the internal heat exchange part which heat-exchanges the refrigerant | coolant in this heat exchanger tube.

The first four-way switching valve 31 and the second four-way switching valve 32 have ports from first to fourth, respectively. The first four-way valve 31 has a first port P1 connected to the discharge side of the compressor 11, a second port P2 connected to the other end of the outdoor heat exchanger 21, and a third port. P3 is connected to the suction side of the compressor 11, and the fourth port P4 is connected to one end of the indoor heat exchanger 22. As shown in FIG. On the other hand, in the second four-way switching valve 32, the first port P1 is connected to the liquid reservoir 52 of the gas-liquid separator 51 via the separation liquid pipe 54, and the second port P2 is It is connected with the heat exchanger tube 50 of the gas-liquid separator 51, the 3rd port P3 is connected with the suction side of the expander 12, and the 4th port P4 is connected with the other end of the indoor heat exchanger 22. do.

The first and second four-way valves 31 and 32 communicate the first port P1 and the second port P2 and communicate the third port P3 with the fourth port P4. A first state (state shown by the solid line in FIG. 19), a first port P1 and a fourth port P4 that communicate with each other, and a second port that communicates with the second port P2 and the third port P3. It is comprised so that switching to a state (state shown with the dotted line of FIG. 19) is possible.

The first four-way switching valve 31 constitutes a refrigerant switching mechanism that switches the circulation direction of the refrigerant to switch between the cooling operation and the heating operation. On the other hand, the second four-way switching valve 32 constitutes a heat exchange amount adjusting mechanism 60 for changing the refrigerant exchange amount in the internal heat exchange unit 50, and the refrigerant in the heat transfer pipe 50 only during the cooling operation of the air conditioner 1. Heat exchange.

Operation operation

Next, operation | movement at the time of cooling operation and heating operation of the 12th Embodiment air conditioner 1 is demonstrated.

(Cooling operation)

As shown in Fig. 20, during the cooling operation, the first four-way switching valve 31 is switched to the first state, and the second four-way switching valve 32 is switched to the second state. When the motor 13 is energized in this state, the refrigerant is circulated in the refrigerant circuit 10 to perform a freezing cycle. At this time, the outdoor heat exchanger 21 becomes a radiator, and the indoor heat exchanger 22 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. The high pressure refrigerant flows into the outdoor heat exchanger 21 through the first four-way switching valve 31. In the outdoor heat exchanger (21), the high pressure refrigerant radiates heat to the outdoor air.

The high pressure refrigerant radiated by the outdoor heat exchanger 21 distributes the heat transfer tube 50 of the gas-liquid separator 51. At this time, the high pressure refrigerant is cooled by heat exchange with the liquid refrigerant stored in the liquid reservoir 52 of the gas-liquid separator 51. The high pressure refrigerant flowing out of the heat transfer pipe (50) flows into the expander (12) through the second cross switching valve (32). In the expander 12, the high pressure refrigerant is expanded, and the internal energy of the high pressure refrigerant is converted into rotational power. By expansion in the expander 12, the high pressure refrigerant is reduced in pressure and changes from a supercritical state to a gas-liquid two-phase state.

The low pressure refrigerant decompressed in the expander 12 flows into the vessel of the gas-liquid separator 51. In the gas-liquid separator 51, the low pressure refrigerant in the gas-liquid two-phase state is separated into a liquid refrigerant and a gas refrigerant. The low pressure liquid refrigerant stored in the liquid storage part 52 is heated by heat exchange with a high pressure refrigerant through which the heat transfer pipe 50 flows. On the other hand, the low pressure gas refrigerant stored in the gas storage part 53 is returned to the suction side of the compressor 11 via the separation gas pipe 55 by opening the gas control valve 38 appropriately at a predetermined opening degree.

The low pressure liquid refrigerant of the liquid reservoir 52 flows into the indoor heat exchanger 22 after passing through the separation liquid pipe 54 and the second four-way switching valve 32. In the indoor heat exchanger (22), the low pressure refrigerant absorbs heat from the indoor air and evaporates. At this time, the indoor air cooled by the low pressure refrigerant is supplied to the room. The low pressure refrigerant evaporated in the indoor heat exchanger (22) passes through the first four-way switching valve (31) and is sucked into the compressor (11).

(Heating operation)

As shown in Fig. 21, during the heating operation, the first four-way switching valve 31 is switched to the second state, and the second four-way switching valve 32 is switched to the first state. When the motor 13 is energized in this state, the refrigerant is circulated in the refrigerant circuit 10 to perform a freezing cycle. At this time, the indoor heat exchanger 22 becomes a radiator, and the outdoor heat exchanger 21 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant, as in the cooling operation.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. This high pressure refrigerant flows into the indoor heat exchanger (22) after passing through the first four way switching valve (31). In the indoor heat exchanger (22), the high pressure refrigerant radiates heat to the indoor air. At this time, the indoor air heated by the high pressure refrigerant is supplied to the room.

The high pressure refrigerant radiated by the indoor heat exchanger (22) flows into the expander (12) through the second four-way switching valve (32). In the expander 12, the high pressure refrigerant is expanded, and the internal energy of the high pressure refrigerant is converted into rotational power. By expansion in the expander 12, the high pressure refrigerant is reduced in pressure and changes from a supercritical state to a gas-liquid two-phase state.

The low pressure refrigerant decompressed in the expander 12 flows into the vessel of the gas-liquid separator 51. In the gas-liquid separator 51, the low pressure refrigerant in the gas-liquid two-phase state is separated into a liquid refrigerant and a gas refrigerant. The low pressure liquid refrigerant stored in the liquid storage part 52 passes through the separation liquid pipe 54 and the second four-way switching valve 32, and then passes through the heat transfer pipe 50. At this time, since the liquid refrigerant in the liquid reservoir 52 and the liquid refrigerant in the heat transfer pipe 50 become substantially isothermal, they are hardly heat exchanged.

The low pressure refrigerant flowing out of the heat transfer pipe 50 flows into the outdoor heat exchanger 21. In the outdoor heat exchanger (21), the low pressure refrigerant absorbs heat from the outdoor air and evaporates. The low pressure refrigerant evaporated in the indoor heat exchanger (22) passes through the first four-way switching valve (31) and is sucked into the compressor (11).

Effect of the twelfth embodiment

According to the twelfth embodiment, the heat transfer tube 50 is provided in the gas-liquid separator 51 as an internal heat exchanger. In addition, by switching the second four-way switching valve 32, the refrigerant flowing through the heat transfer pipe 50 and sucked into the expander 12 and the liquid refrigerant separated from the gas-liquid separator 51 are heat exchanged only during the cooling operation. do. As a result, during the cooling operation, the refrigerant sucked into the expander 12 can be cooled, and the suction refrigerant density de of the expander 12 can be increased. As a result, in the conventional refrigeration apparatus cooling operation, the refrigerant mass flow rate Mc of the compressor 11 becomes larger than the refrigerant mass flow rate Me of the expander 12 for the reasons described above. Since the refrigerant mass flow rate Me of 12) can be increased, both of them (Mc, Me) can be balanced. Therefore, the refrigeration cycle can be executed in this freezer.

In this embodiment, as in Patent Document 2, the refrigerant mass flow rates Mc and Me are balanced without bypassing a part of the refrigerant in the expander. As a result, in the refrigeration apparatus of Patent Document 2, the expansion power of the expander is lowered and the COP is also lowered. In this embodiment, since all the refrigerant can be introduced into the expander 12, such a decrease in COP can be avoided. .

In the above embodiment, the liquid refrigerant separated by the gas-liquid separator 51 and the refrigerant sucked into the expander 12 are heat exchanged. Here, in the same type of coolant, the liquid coolant has a higher heat passing rate than the two-phase coolant or the gas coolant, so that the heat exchange rate in the internal heat exchange part 50 can be improved. Therefore, the refrigerant sucked into the expander 12 can be cooled effectively, and as a result, the internal heat exchanger 50 can be designed compact.

In the above embodiment, since the gas-liquid separator 51 also serves as the internal heat exchanger 50, the refrigeration apparatus can be miniaturized as compared with the case where the gas-liquid separator 51 and the internal heat exchanger 50 are separately provided. Can be.

Moreover, in the said embodiment, what is called gas injection which supplies the gas refrigerant isolate | separated from the gas-liquid separator 51 to the suction side of the compressor 11 is comprised. Therefore, by adjusting the suction refrigerant superheat degree of the compressor 11, it is possible to perform the optimal freezing cycle control in this refrigerating device.

<Modification Example of Twelfth Embodiment>

Next, the refrigeration apparatus of the twelfth embodiment will be described. In the refrigeration apparatus of this modification, a plurality of indoor heat exchangers, which are use side heat exchangers of the air conditioner 1, are provided. That is, the refrigerating device of this modified example is applied to a multifunctional air conditioner. Hereinafter, the point different from 12th Embodiment is demonstrated.

The first to third indoor heat exchangers 22a, 22b and 22c are connected in parallel to the refrigerant circuit 10 of this modification. Each indoor heat exchanger 22a, 22b, 22c is provided with the fan which is not shown in figure, and indoor air is sent to each indoor heat exchanger 22a, 22b, 22c by the corresponding fan, respectively. The refrigerant circuit 10 is provided with first to third flow rate regulating valves 61a, 61b, and 61c corresponding to the indoor heat exchangers 22a, 22b, and 22c, respectively. Each of the flow regulating valves 61a, 61b, and 61c is configured to be capable of adjusting the refrigerant flow rate branched into each of the indoor heat exchangers 22a, 22b, and 22c. Here, the operation of this modification is similar to that of the twelfth embodiment except that each refrigerant branches into the plurality of indoor heat exchangers 22a, 22b, and 22c, flows in, and joins again.

Also in this modification, by cooling the refrigerant in the heat transfer pipe 50 during the cooling operation, the refrigerant sucked into the expander 12 can be cooled to increase the suction refrigerant density de of the expander 12. Therefore, since the refrigerant mass flow rates Mc and Me of the compressor 11 and the expander 12 can be balanced, a desired refrigeration cycle can be performed in the refrigerant circuit 10.

In this modified example, by providing the plurality of indoor heat exchangers 22a, 22b, 22c, this refrigeration apparatus can be applied to the so-called multifunctional air conditioner 1. In addition, since the flow rate of the refrigerant flowing into each of the indoor heat exchangers 22a, 22b, and 22c can be adjusted by each of the flow regulating valves 61a, 61b, and 61c, the cooling capacity or heating of each indoor heat exchanger 22a, 22b, or 22c is controlled. You can adjust your abilities separately. Here, the liquid refrigerant separated by the gas-liquid separator 51 can be sent to each of the indoor heat exchangers 22a, 22b, and 22c. Thus, for example, the flow rate regulating valve ( Flow rate adjustment of 61a, 61b, 61c can be performed easily.

In this multifunctional type, since the communication piping between the indoor heat exchangers 22a, 22b and 22c and the outdoor heat exchanger 21 tends to be long, for example, when the refrigerant in the two-phase state flows through the communication piping, the pressure loss of the refrigerant is reduced. It is easy to increase, and the refrigerant passage sound generated at this time tends to be a noise. On the other hand, in this embodiment, since the liquid refrigerant separated by the gas-liquid separator 51 can be passed through the communication pipe, the pressure loss and noise as described above can be effectively reduced.

[Thirteenth Embodiment]

Next, the refrigeration apparatus of 13th Embodiment is demonstrated. The refrigerating device of the thirteenth embodiment has a different configuration from the refrigerating device of the twelfth embodiment and the refrigerant circuit 10. Hereinafter, the point different from 12th Embodiment is demonstrated.

As shown in FIG. 23, the refrigerant circuit 10 includes the compressor 11, the expander 12, the outdoor heat exchanger 21, the indoor heat exchanger 22, the gas-liquid separator 51, and the like in the twelfth embodiment. The first four-way switching valve 31 and the second four-way switching valve 33 are connected.

Unlike the twelfth embodiment, in the gas-liquid separator 51 of the thirteenth embodiment, one end of the heat transfer tube 50 is connected to the suction side of the inflator 12, and the other end is interposed between the liquid inlet pipe 56 and the first end. 2 is connected to the four-way switching valve (33). The liquid inflow pipe 56 is provided with a first electromagnetic opening / closing valve 34 that allows or prohibits the flow of the refrigerant flowing through the heat transfer pipe 50. In the liquid inflow pipe 56, one end of the bypass pipe 57 is connected between the first electromagnetic opening and closing valve 34 and the second four-way switching valve 33. The other end of the bypass tube 57 is connected to the suction side of the inflator 12. In other words, the bypass pipe 57 bypasses the heat transfer pipe 50 to suck the refrigerant into the expander 12. In addition, the bypass pipe 57 is provided with a second electromagnetic opening and closing valve 35 to allow or prohibit the refrigerant flow of the bypass pipe 57. In the above configuration, the bypass pipe 57 and the first and second electromagnetic opening and closing valves 34 and 35 constitute a heat exchange amount adjusting mechanism 60 for changing the amount of refrigerant heat exchange in the heat transfer pipe 50. The refrigerant is exchanged in the heat transfer pipe 50 only during the cooling operation of the air conditioner 1.

Unlike the twelfth embodiment, the first four-way switching valve 31 has a first port P1 connected to the discharge side of the compressor 11, and a second port P2 connected to one end of the outdoor heat exchanger 21. The third port P3 is connected to the suction side of the compressor 11, and the fourth port P4 is connected to one end of the indoor heat exchanger 22. On the other hand, in the second cross switching valve 33, the first port P1 is connected to the liquid storage part 52 of the gas-liquid separator 51 via the separation liquid pipe 54, and the second port P2 is connected. It is connected to the other end of the outdoor heat exchanger 21, the third port (P3) is connected to the heat transfer stage 50 of the gas-liquid separator 51 via the liquid inlet pipe 56, the fourth port (P4) Is connected to the other end of the indoor heat exchanger (22).

These first and second four-way switching valves 31 and 33 are configured to be switchable between the first state and the second state similarly to the twelfth embodiment. The first and second four-way switching valves 31 and 33 constitute a refrigerant switching mechanism that switches the circulation direction of the refrigerant to switch between the cooling operation and the heating operation.

Operation operation

Next, operation | movement at the time of cooling operation and heating operation of the 13th Embodiment air conditioner 1 is demonstrated.

(Cooling operation)

As shown in Fig. 24, during the cooling operation, the first four-way switching valve 31 is set to the first state, and the second four-way switching valve 33 is set to the second state. Further, the first solenoid valve 34 is opened, and the second solenoid valve 35 is closed. When the motor 13 is energized in this state, the refrigerant is circulated in the refrigerant circuit 10 to perform a freezing cycle. At this time, the outdoor heat exchanger 21 becomes a radiator, and the indoor heat exchanger 22 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. The high pressure refrigerant flows into the outdoor heat exchanger 21 through the first four-way switching valve 31. In the outdoor heat exchanger (21), the high pressure refrigerant radiates heat to the outdoor air.

The high pressure refrigerant radiated by the outdoor heat exchanger 21 passes through the second four-way switching valve 33 and the liquid inflow pipe 56, and then distributes the heat transfer pipe 50. At this time, the high pressure refrigerant is cooled by heat exchange with the liquid refrigerant stored in the liquid reservoir 52 of the gas-liquid separator 51. The high pressure refrigerant flowing out of the heat transfer pipe 50 flows into the expander 12. In the expander 12, the high pressure refrigerant is expanded, and the internal energy of the high pressure refrigerant is converted into the rotational power of the compressor 11. By expansion in the expander 12, the high pressure refrigerant is reduced in pressure and changes from a supercritical state to a gas-liquid two-phase state.

The low pressure refrigerant decompressed in the expander 12 flows into the vessel of the gas-liquid separator 51. In the gas-liquid separator 51, the low pressure refrigerant in the gas-liquid two-phase state is separated into a liquid refrigerant and a gas refrigerant. The low pressure liquid refrigerant stored in the liquid storage part 52 is heated by heat exchange with a high pressure refrigerant through which the heat transfer pipe 50 flows. On the other hand, the low pressure gas refrigerant stored in the gas storage part 53 is returned to the suction side of the compressor 11 via the separation gas pipe 55 by the gas control valve 38 being properly opened with a predetermined opening degree.

The low pressure liquid refrigerant of the liquid reservoir 52 flows into the indoor heat exchanger 22 after passing through the separation liquid pipe 54 and the second crossover switching valve 33. In the indoor heat exchanger (22), the low pressure refrigerant absorbs heat from the indoor air and evaporates. At this time, the indoor air cooled by the low pressure refrigerant is supplied to the room. The low pressure refrigerant evaporated in the indoor heat exchanger (22) passes through the first four-way switching valve (31) and is sucked into the compressor (11).

(Heating operation)

As shown in FIG. 25, during the heating operation, the first four-way switching valve 31 is set to the second state, and the second four-way switching valve 33 is set to the first state. In addition, the first solenoid valve 34 is closed, and the second solenoid valve 35 is opened. When the motor 13 is energized in this state, the coolant is circulated in the coolant circuit 10 to form a freezing cycle. At this time, the indoor heat exchanger 22 becomes a radiator, and the outdoor heat exchanger 21 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant, as in the cooling operation.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. This high pressure refrigerant flows into the indoor heat exchanger (22) through the first four-way valve (31). In the indoor heat exchanger (22), the high pressure refrigerant radiates heat to the indoor air. At this time, the indoor air heated by the high pressure refrigerant is supplied to the room.

The high pressure refrigerant radiated by the indoor heat exchanger 22 flows into the expander 12 through the second four-way switching valve 33 and the bypass pipe 57. In the expander 12, the high pressure refrigerant is expanded, and the internal energy of the high pressure refrigerant is converted into the rotational power of the compressor 11. Due to the expansion in the expander 12, the high pressure refrigerant is reduced in pressure and changes from the supercritical state to the gas-liquid two-phase state.

The low pressure refrigerant decompressed in the expander 12 flows into the vessel of the gas-liquid separator 51. In the gas-liquid separator 51, the low pressure refrigerant in the gas-liquid two-phase state is separated into a liquid refrigerant and a gas refrigerant. At this time, since the refrigerant does not flow through the heat transfer pipe 50, the liquid refrigerant of the liquid storage part 52 is not heat exchanged.

The low pressure liquid refrigerant of the liquid storage part 52 flows into the outdoor exchanger 21 after passing through the separation liquid pipe 54 and the second crossover switching valve 33. In the outdoor heat exchanger (21), the low pressure refrigerant absorbs heat from the outdoor air and evaporates. The low pressure refrigerant evaporated in the outdoor heat exchanger (21) passes through the first four-way switching valve (31) and is sucked into the compressor (11).

Effect of the thirteenth embodiment

According to the thirteenth embodiment, by switching the states of the first and second electromagnetic opening and closing valves 34 and 35, the heat transfer tube 50 is configured to heat exchange only during the cooling operation. In the cooling operation, the suction refrigerant density de of the expander 12 is increased. Therefore, since the refrigerant mass flow rates Mc and Me of the compressor 11 and the expander 12 can be balanced, a desired refrigeration cycle can be performed in the refrigerant circuit 10.

<Modification of 13th Embodiment>

Next, the refrigeration apparatus of the modification of 13th Embodiment is demonstrated. The refrigerating device of the first modification is such that the first and second electric valves 36 and 37 are provided in place of the first and second electromagnetic opening and closing valves 34 and 35 of the thirteenth embodiment. Hereinafter, the point different from 13th Embodiment is demonstrated.

As shown in FIG. 26, in the refrigerant circuit 10 of this modification, the liquid inflow pipe 56 is provided with the 1st electric valve 36 of variable opening degree. This 1st electric valve 36 is comprised so that adjustment of the refrigerant flow volume which distributes the heat exchanger tube 50 is possible. In addition, the bypass pipe 57 is provided with a second transmission valve 37 having a variable opening degree. The second electric valve 37 is configured to be able to adjust the refrigerant flow rate of the bypass pipe 57. And the bypass pipe 57 and the 1st, 2nd electric valves 36 and 37 comprise the heat exchange amount adjustment mechanism 60 which changes the refrigerant heat exchange amount in the heat exchanger tube 50. As shown in FIG.

In this modified example, by adjusting the opening degree of the 1st, 2nd electric valve 36, 37, the flow volume of the refrigerant which flows through the heat exchanger tube 50 can be adjusted, and the amount of refrigerant heat exchange in the heat exchanger tube 50 can be adjusted. . Therefore, the refrigerant mass flow rates Me and Mc of the compressor 11 and the expander 12 can be balanced with high accuracy in response to the operating conditions.

Moreover, by making the 1st electric valve 36 into a fully open state and making the 2nd electric valve 37 fully closed, the refrigerant | coolant is circulated to the heat exchanger tube 50 only at the time of cooling operation, and a heat exchange of a refrigerant | coolant can be performed. have.

Fourteenth Embodiment

Next, the refrigeration apparatus of 14th Embodiment is demonstrated. The refrigeration apparatus of 14th Embodiment differs in the structure of the refrigeration apparatus of 12th Embodiment from the refrigerant circuit 10. As shown in FIG. Hereinafter, the point different from 12th Embodiment is demonstrated.

As shown in FIG. 27, the refrigerant circuit 10 of the fourteenth embodiment is provided with a four-way switching valve 31 in the same manner as the first four-way switching valve of the twelfth embodiment. The four way switching valve 32 is not installed. The four-way switching valve 31 constitutes a refrigerant switching mechanism that switches the circulation direction of the refrigerant to switch between the cooling operation and the heating operation.

On the other hand, in this embodiment, the outdoor heat exchanger 21 and the indoor heat exchanger 22 are connected by the 1st piping 71. In the 1st piping 71, the 1st check valve 81 is provided in the outdoor heat exchanger 21 side, and the 2nd check valve 82 is provided in the indoor heat exchanger 22 side. One end of the liquid inflow pipe 56 is connected between the outdoor heat exchanger 21 and the first check valve 81 in the first pipe 71. The other end of the liquid inflow pipe 56 is connected to one end of the heat transfer pipe 50. The other end of the heat transfer pipe 50 is connected to the suction side of the inflator 12. In addition, a third check valve 83 is provided in the liquid inflow pipe 56.

One end of the separation liquid pipe 54 of the present embodiment is connected to the liquid reservoir 52 of the gas-liquid separator 51, and the other end thereof is the first check valve 81 and the second check valve of the first pipe 71. It is connected between the valve 82. In the first pipe 71, one end of the second pipe 72 is connected between the second check valve 82 and the indoor heat exchanger 22. The other end of the second pipe 72 is connected to the pipe between the suction side of the expander 12 and the gas-liquid separator 51. The fourth check valve 84 is provided in the second pipe 72.

The first check valve 81 allows only a flow of refrigerant from the connection portion of the separation liquid tube 54 to the connection portion of the liquid inflow tube 56 in the first pipe 71. The second check valve 82 allows only a flow of refrigerant from the connection portion of the separation liquid pipe 54 to the connection portion of the second piping 72 in the first piping 71. The third check valve 83 allows only the flow of the refrigerant from the first pipe 71 toward the heat transfer pipe 50. The fourth check valve 84 permits only the flow of the coolant toward the suction side of the expander 12 in the first pipe 71.

As mentioned above, the 1st piping 71, the 2nd piping 72, the liquid inflow pipe 56, and the heat exchanger pipe 50 are connected, and the check valves 81, 82, 83, 84 are provided in this circuit. Thus, in the refrigerant circuit 10 of the present embodiment, a circuit similar to a so-called bridge circuit is formed. And this circuit comprises the heat exchange amount adjustment mechanism 60 which changes the refrigerant heat exchange amount in the heat exchanger tube 50, and coolant heat exchanges in the heat exchanger tube 50 only at the time of cooling operation of the air conditioner 1. As shown in FIG.

Operation operation

Next, operation | movement at the time of cooling operation and heating operation of the 14th Embodiment air conditioner 1 is demonstrated.

(Cooling operation)

As shown in Fig. 28, in the cooling operation, the cross switching valve 31 is set to the first state. When the motor 13 is energized in this state, the refrigerant is circulated in the refrigerant circuit 10 to perform a freezing cycle. At this time, the outdoor heat exchanger 21 becomes a radiator, and the indoor heat exchanger 22 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. This high pressure refrigerant flows into the outdoor heat exchanger 21 via the crossover valve 31. In the outdoor heat exchanger (21), the high pressure refrigerant radiates heat to the outdoor air.

The high pressure refrigerant radiated by the outdoor heat exchanger (21) passes through the third check valve (83) of the liquid inflow pipe (56) and distributes the heat transfer pipe (50). At this time, the high pressure refrigerant is cooled by heat exchange with the liquid refrigerant stored in the liquid reservoir 52 of the gas-liquid separator 51. The high pressure refrigerant flowing out of the heat transfer pipe 50 flows into the expander 12. In the expander 12, the high pressure refrigerant is expanded, and the internal energy of the high pressure refrigerant is converted into the rotational power of the compressor 11. By expansion in the expander 12, the high pressure refrigerant is reduced in pressure and changes from a supercritical state to a gas-liquid two-phase state.

The low pressure refrigerant decompressed in the expander 12 flows into the vessel of the gas-liquid separator 51. At this time, the low pressure refrigerant in the gas-liquid two-phase state is separated into a liquid refrigerant and a gas refrigerant. The low pressure liquid refrigerant stored in the liquid storage part 52 is heated by heat exchange with a high pressure refrigerant through which the heat transfer pipe 50 flows. On the other hand, the low pressure gas refrigerant stored in the gas storage part 53 is returned to the suction side of the compressor 11 via the separation gas pipe 55 by the gas control valve 38 being properly opened with a predetermined opening degree.

The low pressure liquid refrigerant of the liquid storage part 52 flows into the indoor heat exchanger 22 through the separation liquid pipe 54 and through the second check valve 82 of the first pipe 71. In the indoor heat exchanger (22), the low pressure refrigerant absorbs heat from the indoor air and evaporates. At this time, the indoor air cooled by the low pressure refrigerant is supplied to the room. The low pressure refrigerant evaporated in the indoor heat exchanger (22) passes through the crossover valve (31) and is sucked into the compressor (11).

(Heating operation)

As shown in Fig. 29, at the time of heating operation, the cross switching valve 31 is set to the second state. When the motor 13 is energized in this state, the refrigerant is circulated in the refrigerant circuit 10 to perform a freezing cycle. At this time, the indoor heat exchanger 22 becomes a radiator, and the outdoor heat exchanger 21 becomes an evaporator. The high pressure of the refrigeration cycle is set higher than the critical pressure of carbon dioxide, which is a refrigerant, as in the case of refrigerant operation.

The high pressure refrigerant in the supercritical state is discharged from the compressor 11. This high pressure refrigerant flows into the indoor heat exchanger (22) through the crossover valve (31). In the indoor heat exchanger (22), the high pressure refrigerant radiates heat to the outdoor air. At this time, the indoor air heated by the high pressure refrigerant is supplied to the room.

The high pressure refrigerant radiated by the indoor heat exchanger (22) passes through the fourth check valve (84) of the second pipe (72) via the first pipe (71) and flows into the expander (12). In the expander 12, the high pressure refrigerant is expanded, and the internal energy of the high pressure refrigerant is converted into the rotational power of the compressor 11. By expansion in the expander 12, the high pressure refrigerant is reduced in pressure, and changes from a supercritical state to a gas-liquid two-phase state.

The low pressure refrigerant decompressed in the expander 12 flows into the vessel of the gas-liquid separator 51. At this time, the low pressure refrigerant in the gas-liquid two-phase state is separated into a liquid refrigerant and a gas refrigerant. At this time, since the coolant does not flow through the heat transfer pipe 50, the liquid refrigerant of the liquid reservoir 52 is hardly heat exchanged.

The low pressure liquid refrigerant of the liquid reservoir 52 passes through the separation liquid pipe 54 and passes through the first check valve 81 of the first pipe 71 to flow into the outdoor heat exchanger 21. In the outdoor heat exchanger (21), the low pressure refrigerant absorbs heat from the outdoor air and evaporates. The low pressure refrigerant evaporated in the outdoor heat exchanger (21) passes through the crossover valve (31) and is sucked into the compressor (11).

Effect of Fourteenth Embodiment

In the fourteenth embodiment, the combination of the predetermined pipe route and the check valves 81, 82, 83, and 84 is configured to heat exchange the refrigerant in the heat transfer pipe 50 only during the cooling operation. In addition, during the cooling operation, the suction refrigerant density de of the expander 12 is increased. Therefore, the refrigerant mass flow rates Mc and Me of the compressor 11 and the expander 12 can be balanced, and a desired freezing cycle can be performed in the refrigerant circuit 10.

In this embodiment, only the switching control of the four-way switching valve 31 can change the presence or absence of the refrigerant heat exchanger in the heat transfer pipe 50 in accordance with the switching of cooling operation and heating operation. As a result, the control operation in the refrigerant circuit 10 can be easily performed.

Other Embodiments

This invention may be set as the following structures with respect to the said embodiment.

For example, in each of the first to eleventh embodiments described above, an example in which the internal heat exchanger 23 is provided as a temperature regulating means capable of adjusting the temperature of the refrigerant flowing into the expander 12 has been described. In addition to the internal heat exchanger 23, the temperature of the refrigerant may be adjusted.

The temperature adjusting means is not limited to the change in the cooling performance of the refrigerant flowing into the expander 12 during the cooling operation and during the heating operation, and is to adjust the refrigerant temperature when the operating conditions of the refrigerant circuit 10 change. do.

In the 12th to 14th embodiments, the gas refrigerant separated by the gas-liquid separator 51 is sent to the suction side of the compressor 11 via the separation gas pipe 55. However, instead of, or in addition to this, a liquid injection pipe for sending the liquid refrigerant separated from the gas-liquid separator 51 to the suction side of the compressor 11 may be provided.

30 shows an example in which the liquid injection pipe (second injection pipe) 59 is provided in the refrigerating device of the thirteenth embodiment. One end of the liquid inlet pipe 59 is connected to a pipe between the liquid storage unit 52 and the second four-way switching valve 33, and the other end thereof is connected to a suction pipe of the compressor 11. The liquid injection pipe 59 is provided with a liquid control valve 39 for adjusting the refrigerant flow rate of the liquid injection pipe 59.

With the above configuration, the so-called liquid injection can be performed by sending the liquid refrigerant separated by the gas-liquid separator 51 to the suction side of the compressor 11 via the liquid injection pipe 59. At this time, the suction refrigerant superheat degree of the compressor 11 can be adjusted by adjusting the liquid injection amount by the liquid control valve 39. Therefore, it is possible to perform optimal freezing cycle control in this freezing apparatus. Further, by combining the gas injection by the gas injection pipe 55 and the liquid injection by the liquid injection pipe 59, more precise freezing cycle control can be performed. In addition, the liquid injection pipe 59, so-called oil recovery, which returns the refrigeration oil contained in the refrigerant flowing out from the expander 12 together with the liquid refrigerant separated from the gas-liquid separator 51 to the suction side of the compressor (11). It can also be used for piping.

In the above embodiment, the compressor 11 and the expander 12 are constituted by a rotating piston fluid machine, but the present invention is not limited thereto. For example, volumetric fluids such as scroll type, swing type, multi-vane type It may be comprised by a machine etc., and may be comprised combining these volumetric fluid machines (including a rotating piston type).

In addition, although carbon dioxide was used as the refrigerant in the above embodiment, the present invention is not limited thereto, and a natural refrigerant such as HFC refrigerant, HC refrigerant, water, air, ammonia, or the like may be used.

As described above, the present invention is useful for a refrigerating device having a refrigerant circuit for performing a vapor compression refrigeration cycle, wherein an expander constituting the expansion mechanism of the refrigerant circuit is mechanically connected to the compressor.

Claims (29)

delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete The compressor 11, the heat source side heat exchanger 21, the expansion mechanism 12, and the use side heat exchanger 22 are connected, and the refrigerant circuit 10 which performs a vapor compression refrigeration cycle is provided, The expansion mechanism 12 is composed of an expander 12 for generating power by the expansion of the refrigerant, the expander 12 and the compressor 11 is a refrigeration apparatus mechanically connected, A temperature control means 23 capable of controlling the temperature of the refrigerant flowing into the expander 12 is installed, The refrigerant circuit 10 is configured to enable a heating operation in which the refrigerant flowing through the use side heat exchanger 22 radiates heat, and a cooling operation in which the refrigerant flowing through the use side heat exchanger 22 absorbs heat. The temperature control means 23 is configured such that the cooling performance of the refrigerant flowing into the expander 12 is higher in the cooling operation than in the heating operation. And a gas-liquid separator 51 for temporarily storing the refrigerant expanded in the expander 12 into a liquid refrigerant and a gas refrigerant, The gas-liquid separator (51) is provided with a temperature control means including an internal heat exchanger (50) for exchanging heat between the liquid refrigerant separated by the gas-liquid separator (51) and the refrigerant sucked into the expander (12). The method according to claim 18, And a heat exchange amount adjusting mechanism (60) for changing the amount of refrigerant heat exchange in the internal heat exchange part (50) according to the operating conditions. The method according to claim 19, The gas-liquid separator 51 is a liquid reservoir 52 in which the separated liquid refrigerant is stored, and a heat transfer pipe 50 in which the refrigerant sucked into the expander 12 flows adjacent to the liquid reservoir 52. Equipped with And the heat exchanger pipe (50) comprises an internal heat exchanger configured to heat-exchange the liquid refrigerant in the liquid reservoir (52) and the refrigerant in the heat transfer tube (50). The method of claim 20, It is provided with a refrigerant switching mechanism (31, 33) for changing the refrigerant circulation direction of the refrigerant circuit 10 to switch the cooling operation and heating operation, The heat exchange amount adjustment mechanism (60) is a refrigeration apparatus for performing refrigerant heat exchange in the internal heat exchange unit (50) only during the cooling operation. The method according to claim 21, The heat exchange amount adjusting mechanism 60 includes a bypass pipe 57 for bypassing the heat transfer pipe 50 to suck the refrigerant into the expander 12, and a first electric valve for adjusting the flow rate of the refrigerant flowing through the heat transfer pipe 50. 36) and a second electric valve (37) for adjusting the refrigerant flow rate of the bypass pipe (57). The method according to claim 21, The heat exchange amount adjustment mechanism 60 is a refrigeration device composed of a crossover switching valve (32). The method according to claim 21, The heat exchange amount adjusting mechanism 60 bypasses the heat transfer pipe 50 to suck the refrigerant into the expander 12, and the first electrons that allow or prohibit the flow of the coolant through the heat transfer pipe 50. A refrigeration apparatus comprising: an open / close valve (34) and a second electromagnetic open / close valve (35) to allow or prohibit the refrigerant flow of the bypass pipe (57). The method according to claim 21, The heat exchange amount adjustment mechanism (60) is a refrigeration apparatus composed of a combination of a pipe and a check valve (81, 82, 83, 84). The method according to claim 18, The refrigerant circuit 10 includes a first injection pipe 55 for sending gas refrigerant of the gas-liquid separator 51 to the suction side of the compressor 11 and a gas control valve for adjusting the refrigerant flow rate of the first injection pipe 55. A refrigerator, comprising (38). The method according to claim 18, The refrigerant circuit 10 includes a second injection pipe 59 for sending the liquid refrigerant of the gas-liquid separator 51 to the suction side of the compressor 11 and a liquid control valve for adjusting the refrigerant flow rate of the second injection pipe 59. A refrigeration apparatus, comprising (39). The method according to claim 18, A plurality of use-side heat exchangers 22a, 22b, 22c are connected in parallel to the refrigerant circuit 10, And a plurality of flow rate regulating valves (61a, 61b, 61c) for respectively adjusting the flow rate of the refrigerant flowing into the use-side heat exchangers (22a, 22b, 22c). The method according to claim 18, Refrigeration apparatus using carbon dioxide as the refrigerant of the refrigerant circuit (10).

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