KR20070046922A - Freezing apparatus - Google Patents

Abstract

In the refrigerant circuit 11 of the air conditioner 10, a refrigerant adjusting tank 14 is disposed. The refrigerant adjusting tank 14 is disposed immediately after the expander 16. In the refrigerant circuit 11, a liquid injection pipe 31 and a gas injection pipe 33 are disposed. When the liquid side control valve 32 is opened, the liquid refrigerant in the refrigerant adjusting tank 14 is supplied to the suction side of the compressor 15 through the liquid injection pipe 31. On the other hand, when the gas side control valve 34 is opened, the gas refrigerant in the refrigerant adjusting tank 14 is supplied to the suction side of the compressor 15 through the gas injection pipe 33. The state of the refrigerant sucked by the compressor 15 is changed by adjusting the opening degree of the liquid side control valve 32 and the gas side control valve 34, so that the amount of refrigerant passing through the compressor 15 and the amount of refrigerant passing through the expander 16 are adjusted. This balance is achieved.

Refrigeration unit, expander, refrigerant control tank, internal heat exchanger, liquid injection pipe, gas injection pipe

Description

Freezer {FREEZING APPARATUS}

The present invention relates to a refrigerating device having a refrigerant circuit to which a power recovery expander is connected.

Conventionally, as disclosed in Patent Literature 1 or Patent Literature 2, a refrigerating device including a refrigerant circuit to which a power recovery expander is connected and circulating a refrigerant in the refrigerant circuit is known. In this type of refrigerating device, the expander is mechanically connected by a compressor and a shaft or the like. The power obtained by expansion of the refrigerant in the expander is used to drive the compressor, thereby reducing the input to the motor for driving the compressor, thereby improving the coefficient of performance (COP).

In the refrigerating device, the compressor and the expander are connected to the refrigerant circuit which is a closed circuit. Therefore, the mass flow rate of the refrigerant passing through the compressor and the mass flow rate of the refrigerant passing through the expander must always be the same. However, the state (temperature, pressure, density, etc.) of the refrigerant sucked into the compressor or the refrigerant flowing into the expander varies depending on the operating state of the refrigerating device. As a result, for example, when the rotational speeds of the compressor and the expander cannot be set separately, the amount of refrigerant passing through the compressor and the amount of refrigerant passing through the expander are unbalanced, which may make it difficult to perform a freezing cycle under appropriate conditions. have.

Thus, in the refrigerating device disclosed in Patent Document 1, a bypass passage bypassing the inflator is formed. In the operating state where the amount of refrigerant passing through the expander is relatively small, the refrigerant is introduced into the bypass passage to balance the amount of refrigerant passing through the compressor and the amount of refrigerant passing through the expander. In addition, in the refrigerating device disclosed in Patent Document 2, an expansion valve is disposed in series with the expander. In an operation state where the amount of refrigerant passing through the expander is relatively excessive, the refrigerant is expanded at both the expander and the expansion valve to balance the amount of refrigerant passing through the compressor with the amount of refrigerant passing through the expander.

[Patent Document 1: Japanese Patent Laid-Open No. 2001-116371]

[Patent Document 2: Japanese Patent Publication No. 2003-121018]

[Initiation of invention]

[Problem to Solve Invention]

As described above, in the conventional refrigeration apparatus having an expander, by changing the state of the refrigerant passing through the expander, it is possible to balance the amount of passing refrigerant of the compressor and the amount of passing refrigerant of the expander. Therefore, the power that can be recovered from the refrigerant in the expander is reduced, and there is a fear that the improvement of the COP is insufficient. In other words, when a part of the refrigerant bypasses the expander, the amount of refrigerant passing through the expander is reduced, thereby reducing the power obtained in the expander. In addition, when the refrigerant is expanded in both the expansion valve and the expander, the pressure difference at the inlet and outlet of the expander is reduced, and in this case, the power obtained at the expander is also reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a refrigeration apparatus having an expander, which does not reduce the amount of power that can be recovered from the expander, and passes the compressor regardless of the operating state. The purpose of the present invention is to balance the amount of refrigerant and the amount of refrigerant passing through the expander.

[Means for solving the problem]

The first invention is a refrigeration apparatus including a refrigerant circuit (11) to which a power recovery expander (16) is connected and circulating a refrigerant in the refrigerant circuit (11) to perform a refrigeration cycle. And a refrigerant adjusting tank 14 disposed in the middle of the refrigerant flow path from the expander 16 to the compressor 15 of the refrigerant circuit 11 to regulate the amount of refrigerant circulating in the refrigerant circuit 11; A liquid injection passage 31 for supplying the liquid refrigerant in the refrigerant adjusting tank 14 to the suction side of the compressor 15, and a liquid flow rate adjusting mechanism for adjusting the refrigerant flow rate in the liquid injection passage 31; 32).

2nd invention is a 1st invention WHEREIN: The refrigerant | coolant adjustment tank 14 is arrange | positioned downstream from an evaporator among the refrigerant | coolant flow paths which extend from the expander 16 to the compressor 15.

The third invention is that in the first invention, the refrigerant adjusting tank 14 is disposed upstream of the refrigerant flow path from the expander 16 to the compressor 15 in the upstream side.

In the third aspect of the present invention, the gas injection passage (33) for supplying the gas refrigerant in the refrigerant adjusting tank (14) to the suction side of the compressor (15), and the refrigerant flow rate in the gas injection passage (33). It is to provide a gas flow rate control mechanism 34 for adjusting the.

In the fifth invention, in the first, second, third or fourth invention, the high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant.

In the sixth invention, in the first, second, or third invention, the high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant. Control means 90 for manipulating the liquid flow rate adjusting mechanism 32 so that the temperature of the refrigerant discharged from the < RTI ID = 0.0 >

In the fourth invention, in the fourth invention, the high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant, and the temperature of the refrigerant discharged from the compressor 15. And control means 90 for manipulating the liquid flow rate regulating mechanism 32 and the gas flow rate regulating mechanism 34 such that is a predetermined control target value.

In the eighth invention, in the first, second or third invention, the high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant, and the refrigerant circuit ( And control means 90 for manipulating the liquid flow rate regulating mechanism 32 such that the high pressure of the freezing cycle at 11) becomes a predetermined control target value.

In the fourth invention, in the fourth invention, the high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant, and the refrigerating cycle is performed in the refrigerant circuit 11. And control means 90 for manipulating the liquid flow rate regulating mechanism 32 and the gas flow rate regulating mechanism 34 such that the high pressure is a predetermined control target value.

In the sixth invention, in the sixth invention, the control means (90) is based on the operation state of the refrigerating cycle so that the grade factor of the refrigerating cycle made in the refrigerant circuit (11) becomes the highest value obtained in the operation state at that time. It is configured to set the control target value.

In the eleventh invention, in the seventh or ninth invention, the control means 90 operates the refrigeration cycle so that the resultant coefficient of the refrigeration cycle made by the refrigerant circuit 11 becomes the highest value obtained in the operation state at that time. It is configured to set the control target value based on the state.

In the ninth invention, in the ninth invention, the control means (90) is based on the operation state of the refrigerating cycle so that the grade factor of the refrigerating cycle made in the refrigerant circuit (11) becomes the highest value obtained in the operation state at that time. It is configured to set the control target value.

In the thirteenth invention, in any one of the fifth to tenth inventions, the refrigerant circuit 11 is filled with carbon dioxide as a refrigerant.

-Action-

In the first invention, the expander 16 is disposed in the refrigerant circuit 11. The refrigerant discharged from the compressor (15) in the refrigerant circuit (11), for example, radiates heat to outdoor air, expands in the expander (16), and then absorbs from air or the like to evaporate, and then to the compressor (15). Inhaled and compressed. In the coolant circuit 11, the coolant circulates as described above and a freezing cycle is performed. In the refrigerant circuit 11, a refrigerant adjusting tank 14 is disposed. The refrigerant adjusting tank 14 is for adjusting the amount of refrigerant circulating in the refrigerant circuit 11 by changing the amount of liquid refrigerant stored therein.

In the refrigerant circuit 11 of the present invention, the liquid refrigerant in the refrigerant adjusting tank 14 can be supplied to the suction side of the compressor 15 via the liquid injection passage 31. The refrigerant flow rate in the liquid injection passage 31 is adjusted by operating the liquid flow rate adjusting mechanism 32. For example, when the degree of superheat of the refrigerant sucked into the compressor 15 becomes high and its density becomes too small, the amount of refrigerant that can pass through the compressor 15 becomes less than the amount of refrigerant that can pass through the expander 16, and the freezing is performed. There is a possibility that the high pressure of the cycle cannot be set to an appropriate value. In this case, when the liquid refrigerant is supplied to the suction side of the compressor 15 through the liquid injection passage 31, the density of the refrigerant sucked into the compressor 15 increases, and the amount of refrigerant that can pass through the compressor 15 is increased. It is balanced with the amount of refrigerant that can pass through the expander 16.

In the second invention, the refrigerant adjusting tank 14 is disposed in the refrigerant flow path from the evaporator of the refrigerant circuit 11 to the compressor 15. In this refrigerant circuit 11, the refrigerant flowing out of the evaporator once flows into the refrigerant adjusting tank 14. The compressor 15 sucks the saturated gas refrigerant in the refrigerant adjusting tank 14.

In the third invention, the refrigerant adjusting tank 14 is disposed in the refrigerant flow path from the expander 16 to the evaporator of the refrigerant circuit 11. In this refrigerant circuit 11, the refrigerant flowing out of the expander 16 flows into the refrigerant adjusting tank 14 once. The saturated liquid refrigerant in the refrigerant adjusting tank 14 is supplied to the evaporator.

In the fourth aspect of the present invention, the gas refrigerant in the refrigerant adjusting tank 14 can be supplied to the suction side of the compressor 15 through the gas injection passage 33. The refrigerant flow rate in the gas injection passage 33 is adjusted by operating the gas flow rate adjusting mechanism 34. For example, when the refrigerant sucked into the compressor 15 becomes wet and its density becomes too large, the amount of refrigerant that can pass through the compressor 15 becomes excessive compared to the amount of refrigerant that can pass through the expander 16, and the freezing is performed. There is a possibility that the high pressure of the cycle cannot be set to an appropriate value. In this case, when gas refrigerant is supplied to the suction side of the compressor 15 through the gas injection passage 33, the density of the refrigerant sucked into the compressor 15 is reduced, so that the amount of refrigerant that can pass through the compressor 15 is reduced. It is balanced with the amount of refrigerant that can pass through the expander 16.

In the fifth, sixth and seventh inventions, the high pressure of the refrigerating cycle made in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant. That is, the refrigerant discharged from the compressor 15 is in a supercritical state.

In the sixth invention, a control means 90 for operating the liquid flow rate adjusting mechanism 32 is configured. When the control means 90 operates the liquid flow rate adjusting mechanism 32, the flow rate of the refrigerant supplied to the suction side of the compressor 15 through the liquid injection passage 31 is changed. As a result, the suction refrigerant state of the compressor 15 changes, and the discharge refrigerant temperature of the compressor 15 also changes. Then, the control means 90 operates the liquid flow rate adjusting mechanism 32 so that the temperature of the refrigerant discharged from the compressor 15 becomes a predetermined control target value, so that the refrigerant from the liquid injection passage 31 to the compressor 15 is controlled. Adjust the supply.

In the seventh invention, the control means 90 for operating the liquid flow rate regulating mechanism 32 and the gas flow rate regulating mechanism 34 is configured. When the control means 90 operates the liquid flow rate adjusting mechanism 32, the flow rate of the refrigerant supplied to the suction side of the compressor 15 through the liquid injection passage 31 is changed. On the other hand, when the control means 90 operates the gas flow rate adjusting mechanism 34, the flow rate of the refrigerant supplied to the suction side of the compressor 15 through the gas injection passage 33 is changed. As a result, the suction refrigerant density of the compressor 15 is changed, and the discharge refrigerant temperature of the compressor 15 is also changed. Then, the control means 90 operates the liquid flow rate adjusting mechanism 32 so that the temperature of the refrigerant discharged from the compressor 15 becomes a predetermined control target value, so that the refrigerant from the liquid injection passage 31 to the compressor 15 is controlled. The supply amount is adjusted or the amount of refrigerant supplied from the gas injection passage 33 to the compressor 15 is adjusted by operating the gas flow rate adjusting mechanism 34.

In the eighth invention, the control means 90 for operating the liquid flow rate adjusting mechanism 32 is configured. When the control means 90 operates the liquid flow rate adjusting mechanism 32, the flow rate of the refrigerant supplied from the liquid injection passage 31 to the suction side of the compressor 15 is changed, and the suction refrigerant state of the compressor 15 is changed. do. As the discharge refrigerant density of the compressor 15 is changed, the density of the refrigerant flowing into the expander 16 is also changed, thereby changing the high pressure of the refrigeration cycle. The control means 90 operates the liquid flow rate adjusting mechanism 32 so that the high pressure of the refrigerating cycle made by the refrigerant circuit 11 becomes a predetermined control target value from the liquid injection passage 31 to the compressor 15. Adjust the refrigerant supply to the furnace.

In the ninth invention, a control means 90 for operating the liquid flow rate regulating mechanism 32 and the gas flow rate regulating mechanism 34 is configured. When the control means 90 operates the liquid flow rate adjusting mechanism 32, the flow rate of the refrigerant supplied to the suction side of the compressor 15 through the liquid injection passage 31 is changed. On the other hand, when the control means 90 operates the gas flow rate adjusting mechanism 34, the flow rate of the refrigerant supplied to the suction side of the compressor 15 through the gas injection passage 33 is changed. In this way, when the liquid flow rate control mechanism 32 or the gas flow rate control mechanism 34 is operated, the suction refrigerant state of the compressor 15 is changed. And the discharge refrigerant density of the compressor 15 is changed, the density of the refrigerant flowing into the expander 16 is also changed, thereby changing the high pressure of the refrigeration cycle. The control means 90 operates the liquid flow rate adjusting mechanism 32 so that the high pressure of the refrigerating cycle made by the refrigerant circuit 11 becomes a predetermined control target value from the liquid injection passage 31 to the compressor 15. The refrigerant supply amount to the compressor or the gas flow rate control mechanism 34 is operated to adjust the refrigerant supply amount from the gas injection passage 33 to the compressor 15.

In the tenth, eleventh and twelfth inventions, the control means 90 sets the control target value based on the operating state of the refrigerating cycle. At this time, the control means 90 determines the value of the control target value so that the high pressure of the refrigerating cycle becomes a value that can obtain the highest COP in the operation state at that time.

In the thirteenth invention, carbon dioxide (CO ₂ ) is used as the refrigerant to be charged in the refrigerant circuit (11).

[Effects of the Invention]

In the present invention, the liquid injection passage 31 is disposed in the refrigerant circuit 11, and the liquid refrigerant can be supplied to the suction side of the compressor 15 via the liquid injection passage 31. If no countermeasures are taken, the liquid refrigerant is supplied to the suction side of the compressor 15 even in an operating state in which the amount of refrigerant that can pass through the compressor 15 and the amount of refrigerant that can pass through the expander 16 is not balanced. By adjusting the suction refrigerant density of the compressor 15, both of them can be balanced so that the high pressure of the refrigerating cycle can be set to an appropriate value.

As described above, according to the present invention, the amount of refrigerant that can pass through the compressor 15 and the amount of refrigerant that can pass through the expander 16 can be balanced while introducing all of the refrigerant after heat dissipation into the expander 16 as it is. have. Therefore, according to the present invention, the amount of power that can be recovered by the expander 16 is not reduced, and it is possible to balance the amount of refrigerant passing through the compressor 15 with the amount of refrigerant passing through the expander 16 regardless of the operating state. .

In particular, in the fourth aspect of the present invention, the gas refrigerant in the refrigerant adjusting tank 14 can be supplied to the suction side of the compressor 15 by the gas injection passage 33. Therefore, according to the present invention, even if no countermeasures are taken, the compressor (in the gas injection passage 33) is operated even in an operating state in which the amount of refrigerant that can pass through the compressor 15 is excessive compared to the amount of refrigerant that can pass through the expander 16. By supplying the gas refrigerant to the suction side of 15), it becomes possible to balance the amount of refrigerant that can pass through the compressor 15 with the amount of refrigerant that can pass through the expander 16.

In the tenth, eleventh, and twelfth inventions, the control means 90 sets the control target value so as to obtain the best COP in the operation state at that time. Therefore, according to the tenth invention, it is possible to optimize not only a balance between the amount of refrigerant that can pass through the compressor 15 and the amount of refrigerant that can pass through the expander 16, but also to optimize the operating conditions of the refrigerating cycle. .

1 is a piping system diagram of a refrigerant circuit in the air conditioner of the first embodiment.

Fig. 2 is a Moliere diagram (pressure-enthalpy diagram) showing a refrigeration cycle made in the refrigerant circuit.

3 is a piping system diagram of a refrigerant circuit in the air conditioner of the second embodiment.

4 is a piping system diagram of a refrigerant circuit in the air conditioner of the third embodiment.

5 is a piping system diagram of a refrigerant circuit in the air conditioner of the fourth embodiment.

Fig. 6 is a piping system diagram of a refrigerant circuit in the air conditioner of the first modification to the fourth embodiment.

Fig. 7 is a piping system diagram of a refrigerant circuit in the air conditioner of the second modification of the fourth embodiment.

8 is a piping system diagram of a refrigerant circuit in the air conditioner of the third modification to the fourth embodiment.

9 is a piping system diagram of a refrigerant circuit in the air conditioner of the fifth embodiment.

Fig. 10 is a piping system diagram of a refrigerant circuit in the air conditioner of the sixth embodiment.

11 is a piping system diagram of a refrigerant circuit in the air conditioner of the seventh embodiment.

12 is a piping system diagram of a refrigerant circuit in the air conditioner of the eighth embodiment.

Fig. 13 is a piping system diagram of a refrigerant circuit in the air conditioner of the first modification to the eighth embodiment.

Fig. 14 is a piping system diagram of a refrigerant circuit in the air conditioner of the second modification of the eighth embodiment.

Fig. 15 is a piping system diagram of a refrigerant circuit in the air conditioner of the third modification to the eighth embodiment.

Fig. 16 is a piping system diagram of a refrigerant circuit in the air conditioner of the fourth modification of the eighth embodiment.

17 is a piping system diagram of a refrigerant circuit in the air conditioner of the ninth embodiment.

18 is a piping system diagram of a refrigerant circuit in the air conditioner of the tenth embodiment.

19 is a piping system diagram of a refrigerant circuit in the air conditioner of the tenth embodiment of the modification.

20 is a piping system diagram of a refrigerant circuit in the air conditioner of the eleventh embodiment.

[Description of the code]

10: air conditioner (refrigeration device) 11: refrigerant circuit

14: refrigerant adjusting tank 15: compressor

16: inflator 31: liquid injection pipe (liquid injection passage)

32: liquid side control valve (liquid flow control mechanism)

33: gas injection pipe (gas injection passage)

34 gas control valve (gas flow control mechanism)

90 controller (control means)

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

[First embodiment]

A first embodiment of the present invention will be described. The air conditioner 10 of this embodiment is comprised by the refrigeration apparatus which concerns on this invention.

As shown in FIG. 1, the air conditioner 10 includes a refrigerant circuit 11. This refrigerant circuit 11 is a closed circuit filled with carbon dioxide (CO ₂ ) as a refrigerant. The refrigerant circuit 11 includes a compressor 15, an expander 16, an outdoor heat exchanger 12, an indoor heat exchanger 13, and a refrigerant adjusting tank 14. In addition, two four-way selector valves 21 and 22 are arranged in the refrigerant circuit 11.

The compressor 15 and the expander 16 are both constituted by volumetric fluid machines (rotary fluid machines of rocking piston type, rotary fluid machines of rolling piston type, scroll fluid machines, etc.). The compressor 15 and the expander 16 are housed in one casing together with the motor 17. Although not shown, the compressor 15, the expander 16, and the motor 17 are connected by one shaft.

The outdoor heat exchanger 12 and the indoor heat exchanger 13 are both composed of a fin-tube heat exchanger for exchanging a refrigerant with air. In addition, the coolant adjustment tank 14 is a tank formed in a vertical cylindrical shape.

The two four-way selector valves 21 and 22 each have four ports. Each of the four direction selection valves 21 and 22 includes a first state (state shown by a solid line in FIG. 1) in which the first port and the third port communicate with each other, and the second port and the fourth port communicate with each other. The first port and the fourth port communicate with each other, and the second port and the third port communicate with each other (the state shown by a broken line in FIG. 1).

The configuration of the refrigerant circuit 11 will be described. The compressor 15 has its suction side connected to the second port of the first four-way selector valve 21 and its discharge side connected to the first port of the first four-way selector valve 21, respectively. The first four-way selection valve 21 has a third port connected to one end of the outdoor heat exchanger 12 and a fourth port connected to one end of the indoor heat exchanger 13, respectively. The inflator 16 is connected at its inlet side to the third port of the second four way selection valve 22 and its outlet side at the top of the refrigerant adjusting tank 14, respectively. The lower portion of the coolant adjustment tank 14 is connected to the fourth port of the second four-way selection valve 22. The second four-way selection valve 22 has a first port connected to the other end of the outdoor heat exchanger 12 and a second port connected to the other end of the indoor heat exchanger 13, respectively. In this refrigerant circuit (11), the refrigerant adjusting tank (14) is arranged in the middle of the refrigerant flow path from the expander (16) to the side of the outdoor heat exchanger (12) and the indoor heat exchanger (13), which functions as an evaporator.

In the refrigerant circuit 11, a liquid injection pipe 31 constituting the liquid injection passage and a gas injection pipe 33 constituting the gas injection passage are disposed. One end of the liquid injection pipe 31 is connected to the bottom of the refrigerant adjusting tank 14 and the other end to the suction side of the compressor 15. In the middle of the liquid injection pipe | tube 31, the liquid side control valve 32 as a liquid side flow control mechanism is arrange | positioned. One end of the gas injection pipe 33 is connected to the top of the refrigerant adjusting tank 14, and the other end is connected to the suction side of the compressor 15, respectively. In the middle of the gas injection piping 33, the gas side control valve 34 as a gas side flow regulation mechanism is arrange | positioned. Both the liquid side control valve 32 and the gas side control valve 34 are constituted by an electric valve of variable opening degree.

The air conditioner 10 includes a controller 90 as a control means. The controller 90 is configured to perform opening degree control of the liquid side control valve 32 and the gas side control valve 34. Specifically, the controller 90 sets the target value of the discharge refrigerant temperature of the compressor 15 as the control target value, and the liquid side control valve 32 so that the actual value of the discharge refrigerant temperature of the compressor 15 becomes the control target value. And the opening degree of the gas side control valve 34 is adjusted. At this time, the controller 90 sets the high pressure value of the refrigeration cycle in which the coefficient of performance COP of the refrigeration cycle becomes the highest in the operation state at that time as the control target value.

Operation operation

The operation of the air conditioner 10 will be described.

<Cooling operation>

In the cooling operation, the first four-way selection valve 21 and the second four-way selection valve 22 are set to the first state (the state shown by the solid line in FIG. 1), so that the refrigerant in the refrigerant circuit 11 It cycles as shown by the solid arrow in FIG. At this time, the outdoor heat exchanger 12 becomes a gas cooler, and the indoor heat exchanger 13 becomes an evaporator.

Specifically, the supercritical refrigerant discharged from the compressor 15 flows into the outdoor heat exchanger 12 to radiate heat to the outdoor air and then flows into the expander 16. In the expander 16, the introduced refrigerant is expanded, and the power thus obtained is transmitted to the compressor 15. The refrigerant in the gas liquid two-phase state flowing out of the expander 16 flows into the refrigerant adjusting tank 14 and is separated into a liquid refrigerant and a gas refrigerant. The liquid refrigerant flowing out of the refrigerant adjusting tank 14 flows into the indoor heat exchanger 13 and endothermic from the indoor air and evaporates. In the indoor heat exchanger (13), indoor air is cooled by the refrigerant. The refrigerant evaporated in the indoor heat exchanger (13) is sucked into the compressor (15) and compressed.

<Heating operation>

At the time of heating operation, the first four-way selection valve 21 and the second four-way selection valve 22 are set to the second state (the state indicated by broken lines in FIG. 1), so that the refrigerant in the refrigerant circuit 11 It cycles as indicated by the dashed arrows in FIG. At this time, the indoor heat exchanger 13 becomes a gas cooler, and the outdoor heat exchanger 12 becomes an evaporator.

Specifically, the supercritical refrigerant discharged from the compressor 15 flows into the indoor heat exchanger 13 to radiate heat into the indoor air and then flows into the expander 16. In the indoor heat exchanger (13), indoor air is heated by the refrigerant. In the expander 16, the introduced refrigerant is expanded, and the power thus obtained is transmitted to the compressor 15. The refrigerant in the gas liquid two-phase state flowing out of the expander 16 flows into the refrigerant adjusting tank 14 and is separated into a liquid refrigerant and a gas refrigerant. The liquid refrigerant flowing out of the refrigerant adjusting tank 14 flows into the outdoor heat exchanger 12 and endothermic from the outdoor air and evaporates. The refrigerant evaporated in the outdoor heat exchanger 12 is sucked into the compressor 15 and compressed.

Control operation of controller

First, when the opening degree of the liquid side control valve 32 and the gas side control valve 34 is changed, it demonstrates how the operation state of a refrigeration cycle changes.

The Moliere diagram (pressure-enthalpy diagram) of FIG. 2 shows a refrigeration cycle in which the evaporation pressure of the refrigerant (ie, the low pressure of the refrigeration cycle) is P _L and the refrigerant temperature at the outlet of the gas cooler is T _gc . The refrigeration cycle in which the best performance factor is obtained in this operating state is the refrigeration cycle indicated by ABCD. That is, it is assumed that when the temperature of the refrigerant discharged from the compressor 15 is T _d (that is, when the high pressure of the freezing cycle is P _H ), the COP of the freezing cycle becomes the highest.

Here, in the so-called supercritical cycle in which the high pressure of the refrigerating cycle exceeds the critical pressure of the refrigerant, the evaporation pressure of the refrigerant (that is, the low pressure of the refrigerating cycle) and the state of the refrigerant sucked into the compressor 15 (specifically, the degree of superheat) Or wetness) and the refrigerant temperature at the outlet of the gas cooler, it is possible to specify the high pressure of the freezing cycle in which the COP of the freezing cycle is the highest.

In the refrigerant circuit 11, a refrigeration cycle represented by A'-B'-C'-D 'is assumed. At this time, the state of the refrigerant sucked into the compressor 15 is the state of point A '. The refrigerant in the point A 'state is lower in density than the refrigerant in the point A state. In this case, when the liquid refrigerant supply from the liquid injection pipe 31 is started or the liquid refrigerant supply amount from the liquid injection pipe 31 is increased, the refrigerant sucked into the compressor 15 is kept at the point A '. The density increases as it approaches the point A state. When the density of the refrigerant sucked into the compressor 15 increases, the density of the refrigerant flowing into the expander 16 also increases accordingly. As a result, the point C 'moves closer to the point C by moving the isotherm on the temperature T _gc in the direction of increasing density. In addition, the high pressure P ' _H of the refrigerating cycle increases and approaches the pressure P _H , and the discharge refrigerant temperature of the compressor 15 decreases to approach the temperature T _d , and the entire refrigerating cycle reaches ABCD. Get closer to the ideal displayed.

In the refrigerant circuit 11, a refrigeration cycle represented by A "-B" -C "-D" is assumed. At this time, the state of the refrigerant sucked into the compressor 15 is the state of point A ". The refrigerant of the point A" state is higher in density than the refrigerant of the point A state. In this case, when the gas refrigerant supply from the gas injection pipe 33 is started or the gas refrigerant supply amount from the gas injection pipe 33 is increased, the refrigerant sucked into the compressor 15 is in the state of point A ". The density decreases near the point A. When the density of the refrigerant sucked into the compressor 15 decreases, the density of the refrigerant flowing into the expander 16 decreases accordingly. The isotherm on T _gc ) moves in the direction of decreasing density and approaches point C. The high pressure P ″ _H of the refrigerating cycle decreases and approaches the pressure P _H , and the discharge refrigerant temperature of the compressor 15 rises to approach the temperature T _d , and the entire refrigerating cycle reaches ABCD. Get closer to the ideal displayed.

Next, the control operation of the controller 90 will be described. As described above, the controller 90 sets a control target value related to the discharge refrigerant temperature from the compressor 15. Specifically, the controller 90 obtains the measured value of the refrigerating cycle low pressure pressure and the measured value of the gas cooler outlet refrigerant temperature from a sensor or the like. On the other hand, the controller 90 stores in advance the discharge refrigerant temperature of the compressor 15 at which the COP of the refrigeration cycle becomes the highest as a function of the low pressure pressure of the refrigeration cycle and the refrigerant temperature at the outlet of the gas cooler. At this time, the suction refrigerant state of the compressor 15 is determined in advance such as, for example, "superheat degree 5" or "saturation state". The controller 90 performs calculation by substituting the measured value acquired into this stored function, and sets the value obtained as a control target value.

The controller 90 compares the set control target value with the measured value of the discharged refrigerant temperature of the compressor 15 and adjusts the opening degree of the liquid side control valve 32 or the gas side control valve 34 based on the result. To control.

For example, it is assumed that the measured value of the discharged refrigerant temperature of the compressor 15 is higher than the control target value. At this time, if the gas side control valve 34 is open, the controller 90 tightens the opening degree of the gas side control valve 34. Even when the gas side control valve 34 is fully closed, if the actual value of the compressor 15 discharge refrigerant temperature is still higher than the control target value, the controller 90 increases the opening degree of the liquid side control valve 32. On the contrary, it is assumed that the measured value of the discharge temperature of the compressor 15 is lower than the control target value. At this time, if the liquid side control valve 32 is open, the controller 90 tightens the opening degree of the liquid side control valve 32. If the actual value of the refrigerant 15 discharge refrigerant temperature is still lower than the control target value even when the liquid side control valve 32 is fully closed, the controller 90 increases the opening degree of the gas side control valve 34. .

Effect of the first embodiment

In the air conditioner 10 of this embodiment, the liquid injection pipe | tube 31 is comprised in the refrigerant | coolant circuit 11, and it can comprise the liquid refrigerant supply to the suction side of the compressor 15 via this liquid injection pipe | tube 31. . If no countermeasures are taken, the liquid refrigerant is supplied to the suction side of the compressor 15 even in an operating state where the balance between the amount of refrigerant that can pass through the compressor 15 and the amount of refrigerant that can pass through the expander 16 is lost. By adjusting the suction refrigerant density of the compressor 15, it is possible to achieve a balance between them to set the high pressure of the refrigerating cycle to an appropriate value.

As described above, according to the present embodiment, the amount of refrigerant that can pass through the compressor 15 and the amount of refrigerant that can pass through the expander 16 while introducing all the refrigerant flowing out of the gas cooler into the expander 16 as it is. It can be balanced. Therefore, according to the present embodiment, the amount of power that can be recovered by the expander 16 is not reduced, and it is possible to balance the passage refrigerant amount of the compressor 15 and the passage refrigerant amount of the expander 16 regardless of the operating state. Become.

In the air conditioner 10 of the present embodiment, the gas refrigerant in the refrigerant adjusting tank 14 can be supplied to the suction side of the compressor 15 by the gas injection pipe 33. Therefore, according to the present embodiment, even if no countermeasures are taken, the amount of the refrigerant that can pass through the compressor 15 is greater than that of the refrigerant that can pass through the expander 16, so that the gas injection pipe 33 By supplying gas refrigerant to the suction side of the compressor 15, the amount of refrigerant that can pass through the compressor 15 and the amount of refrigerant that can pass through the expander 16 can be balanced.

Second Embodiment

A second embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant | coolant circuit 11 and the controller 90 in the air conditioner 10 of the said 1st Embodiment. Here, the difference from the said 1st Embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in FIG. 3, in the refrigerant circuit 11 of the present embodiment, a bridge circuit 40 is formed instead of the second four-way selection valve 22. The bridge circuit 40 connects four check valves 41 to 44 in the form of a bridge. The bridge circuit 40 has a second check valve 42 and a third check valve 43 on the inflow side of the first check valve 41 and the fourth check valve 44 on the outflow side of the expander 16. ) Is the inflow side of the inflator 16, the outflow side of the first check valve 41 and the inflow side of the second check valve 42 is the other end of the indoor heat exchanger 13, the third check valve The inlet side of 43 and the outlet side of the fourth check valve 44 are connected to the other end of the outdoor heat exchanger 12, respectively.

In the refrigerant circuit 11 of the present embodiment, the arrangement of the refrigerant adjusting tank 14 is different from that of the first embodiment. In this refrigerant circuit 11, the refrigerant adjusting tank 14 is arranged in the middle of the refrigerant flow path from the outdoor heat exchanger 12 and the indoor heat exchanger 13 to the compressor 15 on the side functioning as an evaporator. Specifically, the refrigerant adjusting tank 14 is connected at its upper end to the second port of the first four-way selection valve 21 and at its upper end to the suction side of the compressor 15, respectively.

In the refrigerant circuit 11 of the present embodiment, only the liquid injection pipe 31 and the liquid side control valve 32 are disposed, and the gas injection pipe 33 and the gas side control valve 34 are omitted. In this refrigerant circuit 11, one end of the liquid injection pipe 31 is connected to the bottom of the refrigerant adjusting tank 14, and the other end is connected to the suction side of the compressor 15. This point is the same as that of the said 1st Embodiment.

Moreover, the controller 90 of this embodiment is comprised so that only the opening degree of the liquid side control valve 32 may be adjusted by omitting the gas injection piping 33 and the gas side control valve 34. That is, the controller 90 sets the target value of the discharge refrigerant temperature of the compressor 15 as the control target value, and sets the target value of the liquid side control valve 32 so that the actual value of the discharge refrigerant temperature of the compressor 15 becomes the control target value. Adjust the opening.

Operation operation

The operation of the air conditioner 10 will be described.

<Cooling operation>

In the cooling operation, the first four-way selector valve 21 is set to the first state (the state indicated by the solid line in FIG. 3), and the refrigerant circulates in the refrigerant circuit 11 as indicated by the solid arrow in FIG. 3. do. At this time, the outdoor heat exchanger 12 becomes a gas cooler, and the indoor heat exchanger 13 becomes an evaporator.

Specifically, the supercritical refrigerant discharged from the compressor 15 flows into the outdoor heat exchanger 12, radiates heat to outdoor air, and then flows into the expander 16. In the expander 16, the introduced refrigerant is expanded, and the power thus obtained is transmitted to the compressor 15. The refrigerant in the gas-liquid two-phase state flowing out of the expander 16 flows into the indoor heat exchanger 13 and endothermic from the indoor air and evaporates. In the indoor heat exchanger (13), indoor air is cooled by the refrigerant. The refrigerant passing through the indoor heat exchanger (13) flows into the refrigerant adjusting tank (14), and the gas refrigerant in the refrigerant adjusting tank (14) is sucked into the compressor (15) and compressed. At this time, since the liquid refrigerant is stored in the refrigerant adjusting tank 14, the gas refrigerant sucked into the compressor 15 from the refrigerant adjusting tank 14 is saturated.

<Heating operation>

At the time of heating operation, the first four-way selection valve 21 is set to the second state (the state shown by the broken line in FIG. 3), and the refrigerant in the refrigerant circuit 11 is indicated by the dotted arrows in FIG. 3. Circulate At this time, the indoor heat exchanger 13 becomes a gas cooler, and the outdoor heat exchanger 12 becomes an evaporator.

Specifically, the supercritical refrigerant discharged from the compressor 15 flows into the indoor heat exchanger 13, radiates heat into the indoor air, and then flows into the expander 16. In the indoor heat exchanger (13), indoor air is heated by the refrigerant. In the expander 16, the introduced refrigerant is expanded, and the power thus obtained is transmitted to the compressor 15. The refrigerant in the gas liquid two-phase state flowing out of the expander 16 flows into the outdoor heat exchanger 12 and is endothermic from the outdoor air and evaporates. The refrigerant passing through the outdoor heat exchanger 12 flows into the refrigerant adjusting tank 14, and the gas refrigerant in the refrigerant adjusting tank 14 is sucked into the compressor 15 and compressed. At this time, since the liquid refrigerant is stored in the refrigerant adjusting tank 14, the gas refrigerant sucked into the compressor 15 from the refrigerant adjusting tank 14 is saturated.

Control operation of controller

The controller 90 sets a control target value relating to the discharge refrigerant temperature of the compressor 15. At this time, the controller 90 sets the control target value in the same manner as in the case of the first embodiment. That is, the controller 90 calculates the discharge refrigerant temperature of the compressor 15 at which the COP of the refrigeration cycle is the highest by performing calculation based on the low pressure pressure actual value of the refrigeration cycle and the refrigerant temperature actual value of the gas cooler outlet. The value is set as the control target value.

The controller 90 compares the set control target value with the actual measurement value of the discharged refrigerant temperature of the compressor 15, and controls the opening degree of the liquid side control valve 32 based on the result. That is, the controller 90 enlarges the opening degree of the liquid side control valve 32 when the measured value of the discharged refrigerant temperature of the compressor 15 is higher than the control target value, while controlling the measured value of the discharged refrigerant temperature of the compressor 15. If lower than the target value, the opening of the liquid side control valve 32 is reduced.

[Third Embodiment]

A third embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant circuit 11 in the air conditioner 10 of the said 2nd Embodiment. Here, the difference from the said 2nd Embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in FIG. 4, the internal heat exchanger 50 is added to the refrigerant circuit 11 of this embodiment. The internal heat exchanger 50 is provided with the 1st flow path 51 and the 2nd flow path 52, and heat-exchanges the refrigerant | coolant of the 1st flow path 51 and the refrigerant | coolant of the 2nd flow path 52. As shown in FIG. In the internal heat exchanger 50, the heat transfer area facing the second flow path 52 is larger than the heat transfer area facing the first flow path 51. The internal heat exchanger (50) has a first flow path (51) connected to a pipe between the bridge circuit (40) and the outdoor heat exchanger (12), and the second flow path (52) has a bridge circuit (40) and an indoor heat exchanger. It is connected to the pipe between (13).

Operation operation

In the cooling operation, the coolant circulates in the coolant circuit 11 as indicated by the solid arrows in FIG. 4. At this time, in the internal heat exchanger 50, the liquid refrigerant flowing out of the outdoor heat exchanger 12 flows through the first flow path 51, and the refrigerant in the gas liquid two-phase state flowing out of the expander 16 flows into the second flow path 52. Flows) That is, in the internal heat exchanger 50, the refrigerant in the gas liquid two-phase state flows through the second flow path 52 having a large heat transfer area. As a result, the amount of heat exchange between the refrigerant in the first flow path 51 and the refrigerant in the second flow path 52 becomes relatively large, and the temperature of the liquid refrigerant decreases relatively large while passing through the first flow path 51. The coolant whose temperature has decreased while passing through the first flow path 51 flows into the expander 16 after that. As described above, the expander 16 is introduced with a refrigerant having a high density by cooling in the internal heat exchanger 50.

On the other hand, during the heating operation, the refrigerant circulates in the refrigerant circuit 11 as indicated by the dotted arrows in FIG. 4. At this time, in the internal heat exchanger 50, the refrigerant in the gas liquid two-phase state flowing out of the expander 16 flows through the first flow path 51, and the liquid refrigerant flowing out of the indoor heat exchanger 13 flows into the second flow path 52. Flows) That is, in the internal heat exchanger 50, the refrigerant in the gas liquid two-phase state flows through the first flow path 51 having a narrow heat transfer area. As a result, the amount of heat exchange between the refrigerant in the first flow path 51 and the refrigerant in the second flow path 52 is relatively small, and the temperature of the liquid refrigerant does not decrease so much while passing through the first flow path 51. The refrigerant passing through the first flow path 51 flows into the expander 16 after that. In this way, the expander 16 is introduced with a refrigerant which is not cooled in the internal heat exchanger 50 and whose density is almost unchanged.

Fourth Embodiment

A fourth embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant circuit 11 in the air conditioner 10 of the said 3rd Embodiment. Here, the difference from the said 3rd Embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in Fig. 5, in the refrigerant circuit 11 of the present embodiment, the arrangement of the refrigerant adjusting tank 14 is different from that of the third embodiment. In this refrigerant circuit 11, the refrigerant adjusting tank 14 is disposed in the middle of the refrigerant flow path from the expander 16 to the side of the outdoor heat exchanger 12 and the indoor heat exchanger 13, which functions as an evaporator.

The fifth check valve 45 and the sixth check valve 46 are added to the refrigerant circuit 11. The fifth check valve 45 is arranged in a pipe connecting the second flow path 52 of the internal heat exchanger 50 and the indoor heat exchanger 13. The fifth check valve 45 is arranged in such a manner that its inflow side is the indoor heat exchanger 13 side and its outflow side is the internal heat exchanger 50 side. The sixth check valve 46 is arranged in a pipe connecting the first flow path 51 of the internal heat exchanger 50 and the outdoor heat exchanger 12. The sixth check valve 46 is arranged in such a manner that its inflow side is the outdoor heat exchanger 12 side and its outflow side is the internal heat exchanger 50 side.

In addition, an introduction tube 60 is added to the refrigerant circuit 11. One end of this inlet pipe 60 is connected to the top of the coolant adjustment tank 14. The other end of the introduction pipe 60 branches into two, and the branched one becomes the first introduction branch pipe 61 and the other side becomes the second introduction branch pipe 62. The first inlet branch pipe 61 is connected between the fifth check valve 45 and the internal heat exchanger 50. The first electromagnetic inlet valve 61 is provided with a first electromagnetic valve 56. The second inlet branch pipe 62 is connected between the sixth check valve 46 and the internal heat exchanger 50. The second solenoid valve 57 is disposed in the second introduction branch pipe 62.

In addition, a first lead pipe 68 and a second lead pipe 69 are added to the refrigerant circuit 11. One end of the first outlet pipe 68 is connected to the lower portion of the refrigerant adjusting tank 14, and the other end is connected between the indoor heat exchanger 13 and the fifth check valve 45, respectively. The first check pipe 68 is provided with a seventh check valve 47 that permits only flow of refrigerant from one end to the other. One end of the second lead pipe 69 is connected to the lower portion of the refrigerant adjusting tank 14, and the other end thereof is connected between the outdoor heat exchanger 12 and the sixth check valve 46, respectively. In the second lead pipe 69, an eighth check valve 48 that allows only a flow of refrigerant from one end to the other end is disposed.

Operation operation

In the cooling operation, the first solenoid valve 56 is opened and the second solenoid valve 57 is closed. In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant in the gas-liquid two-phase state flowing out of the expander 16 passes through the second flow path 52 of the internal heat exchanger 50 and then passes through the first introduction branch pipe 61 to adjust the refrigerant adjusting tank ( 14). In the refrigerant adjusting tank 14, the introduced refrigerant is separated into a liquid refrigerant and a gas refrigerant. The liquid refrigerant in the refrigerant adjusting tank 14 flows into the indoor heat exchanger 13 through the first lead pipe 68.

On the other hand, in the heating operation, the first solenoid valve 56 is closed and the second solenoid valve 57 is opened. In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant in the gas liquid two-phase state flowing out of the expander 16 passes through the first flow path 51 of the internal heat exchanger 50 and then passes through the second introduction branch pipe 62 to adjust the refrigerant adjusting tank ( 14). In the refrigerant adjusting tank 14, the introduced refrigerant is separated into a liquid refrigerant and a gas refrigerant. The liquid refrigerant in the refrigerant adjusting tank 14 flows into the outdoor heat exchanger 12 through the second lead pipe 69.

First Modified Example of the Fourth Embodiment

In this embodiment, the refrigerant circuit 11 may be configured as follows.

As shown in FIG. 6, in the refrigerant circuit 11 of the present modification, the first three-way valve 26 is disposed instead of the first solenoid valve 56 and the second solenoid valve 57. The first three-way valve 26 is disposed at a position where the first introduction branch pipe 61 and the second introduction branch pipe 62 join in the introduction pipe 60. The first three-way valve 26 has a first introduction branch pipe 61 connected to the second port thereof, and a second introduction branch pipe 62 connected to the third port thereof.

In the refrigerant circuit 11, a lead pipe 65 is disposed instead of the first lead pipe 68 and the second lead pipe 69. One end of the lead pipe 65 is connected to the lower portion of the refrigerant adjusting tank 14. The other end of the lead pipe 65 is divided into two, and the branched one becomes the first lead branch branch 66 and the other leads to the second lead branch branch 67. The first outlet branch pipe 66 is connected between the indoor heat exchanger 13 and the fifth check valve 45. The second outlet branch pipe 67 is connected between the outdoor heat exchanger 12 and the sixth check valve 46.

A second three-way valve 27 is disposed in the lead pipe 65. The second three-way valve 27 is disposed at a location where the first lead branch pipe 66 and the second lead branch pipe 67 join together. In the second three-way valve 27, a first lead branch pipe 66 is connected to the second port thereof, and a second lead branch pipe 67 is connected to the third port thereof.

In the cooling operation, both the first three-way valve 26 and the second three-way valve 27 are set to a state in which the first port and the second port communicate with each other (state shown by a solid line in FIG. 6). In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant in the gas-liquid two-phase state flowing out of the expander 16 passes through the second flow path 52 of the internal heat exchanger 50 and then passes through the first introduction branch pipe 61 to adjust the refrigerant adjusting tank ( 14). In addition, the liquid refrigerant in the refrigerant adjusting tank 14 flows into the indoor heat exchanger 13 through the first outlet branch pipe 66.

On the other hand, in the heating operation, both the first three-way valve 26 and the second three-way valve 27 are set to a state in which the first port and the third port communicate (the state indicated by broken lines in FIG. 6). In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant in the gas liquid two-phase state flowing out of the expander 16 passes through the first flow path 51 of the internal heat exchanger 50 and then passes through the second introduction branch pipe 62 to adjust the refrigerant adjusting tank ( 14). In addition, the liquid refrigerant in the refrigerant adjusting tank 14 flows into the outdoor heat exchanger 12 through the second outlet branch pipe 67.

Second Modified Example of the Fourth Embodiment

In this embodiment, the refrigerant circuit 11 may be configured as follows.

As shown in FIG. 7, in the refrigerant circuit 11 of the present modification, a second four-way selection valve 22 is disposed instead of the bridge circuit 40. The second four-way selector valve 22 has a first port at the first flow path 51 of the internal heat exchanger 50, a second port at the second flow path 52 of the internal heat exchanger 50, and a third port. The fourth port is connected to the inflow side of the inflator 16 and the outflow side of the inflator 16, respectively.

In the refrigerant circuit 11, the first and second solenoid valves 56 and 57 and the fifth to eighth check valves 45 to 48 are omitted, and instead, the third four-way selection valve 23 is used. And a fourth four-way selector valve 24 is disposed. The third four-way selector valve 23 has a first port connected to the first outlet pipe 68, a second port connected to the second flow path 52 of the internal heat exchanger 50, and a third port connected to the indoor heat exchanger ( At the other end of 13), a fourth port is connected to the first introduction branch pipes 61, respectively. The fourth four-way selector valve 24 has a first port at the other end of the outdoor heat exchanger 12, a second port at the second introduction branch pipe 62, and a third port at the other end of the internal heat exchanger 50. The 4th port is connected to the 1st flow path 51 to the 2nd lead pipe 69, respectively.

At the time of cooling operation, all the four direction selection valves 21-24 are set to the state shown by the solid line in FIG. In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant in the gas-liquid two-phase state flowing out of the expander 16 passes through the second flow path 52 of the internal heat exchanger 50 and then passes through the first introduction branch pipe 61 to adjust the refrigerant adjusting tank ( 14). The liquid refrigerant in the refrigerant adjusting tank 14 flows into the indoor heat exchanger 13 through the first lead pipe 68.

On the other hand, at the time of heating operation, all the four direction selection valves 21-24 are set to the state shown with the broken line in FIG. In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant in the gas liquid two-phase state flowing out of the expander 16 passes through the first flow path 51 of the internal heat exchanger 50 and then passes through the second introduction branch pipe 62 to adjust the refrigerant adjusting tank ( 14). The liquid refrigerant in the refrigerant adjusting tank 14 flows into the outdoor heat exchanger 12 through the second lead pipe 69.

Third modified example of the fourth embodiment

In this embodiment, the refrigerant circuit 11 may be configured as follows.

As shown in Fig. 8, in the refrigerant circuit 11 of the present modification, a second four-way selection valve 22 is disposed instead of the bridge circuit 40. As shown in Figs. The second four-way selector valve 22 has a third port selected from the third four-way selector valve 23, which will be described later, a second port connected to the second flow path 52 of the internal heat exchanger 50, and a third port. On the inflow side of the inflator 16, a fourth port is connected to the outflow side of the inflator 16, respectively.

In the refrigerant circuit 11, the sixth check valve 46 is omitted, and a third four-way selection valve 23 and a third solenoid valve 58 are added instead. The third four-way selector valve 23 has a first port at the other end of the outdoor heat exchanger 12, a second port at the first port of the second four-way selector valve 22, and a third port at the internal heat exchanger. (50) At one end of the first flow path 51, a fourth port is connected to the other end of the first flow path 51 of the internal heat exchanger 50, respectively. The third solenoid valve 58 is disposed between the fourth port of the third four-way valve 23 and the first flow path 51 of the internal heat exchanger 50.

In the refrigerant circuit 11, the connection position of the second introduction branch pipe 62 and the second lead pipe 69 is changed. The second introduction branch pipe 62 is connected between the first flow path 51 of the internal heat exchanger 50 and the third solenoid valve 58. The second lead pipe 69 is connected between the fourth port of the third four-way selection valve 23 and the third solenoid valve 58.

In the cooling operation, all four-way selector valves 21 to 23 are set to the state shown by the solid line in FIG. 8, and the first solenoid valve 56 and the third solenoid valve 58 are opened and the second solenoid valve is opened. 57 is closed. In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant in the gas-liquid two-phase state flowing out of the expander 16 passes through the second flow path 52 of the internal heat exchanger 50 and then passes through the first introduction branch pipe 61 to adjust the refrigerant adjusting tank ( 14). The liquid refrigerant in the refrigerant adjusting tank 14 flows into the indoor heat exchanger 13 through the first lead pipe 68.

On the other hand, in the heating operation, all four-way selector valves 21 to 23 are set in the state shown by broken lines in FIG. 8, and the first solenoid valve 56 and the third solenoid valve 58 are closed and the second The solenoid valve 57 is opened. In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant in the gas liquid two-phase state flowing out of the expander 16 passes through the first flow path 51 of the internal heat exchanger 50 and then passes through the second introduction branch pipe 62 to adjust the refrigerant adjusting tank ( 14). The liquid refrigerant in the refrigerant adjusting tank 14 flows into the outdoor heat exchanger 12 through the second lead pipe 69.

[Fifth Embodiment]

A fifth embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant circuit 11 in the air conditioner 10 of the said 1st Embodiment. Here, the difference from the said 1st Embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in FIG. 9, in the refrigerant circuit 11 of this embodiment, arrangement | positioning of the 1st 4-way direction selection valve 21 and the 2nd 4-way direction selection valve 22 differs from the said 1st Embodiment. The first four-way valve 21 has a first port at the discharge side of the compressor 15, a second port at the bottom of the refrigerant adjusting tank 14, and a third port at one end of the outdoor heat exchanger 12. The fourth port is connected to the other end of the indoor heat exchanger 13, respectively. The second four-way selector valve 22 has a first port at the other end of the outdoor heat exchanger 12, a second port at one end of the indoor heat exchanger 13, and a third port at the inlet side of the expander 16. The fourth port is connected to the suction side of the compressor 15, respectively. The liquid injection pipe 31 and the gas injection pipe 33 are both connected between the suction side of the compressor 15 and the second four-way selection valve 22.

Operation operation

In the cooling operation, both the first four-way selection valve 21 and the second four-way selection valve 22 are set to the first state (the state shown by the solid line in FIG. 9). In the refrigerant circuit 11, the refrigerant is circulated as indicated by the solid arrows in FIG. That is, the refrigerant discharged from the compressor 15 passes through the outdoor heat exchanger 12, the expander 16, the refrigerant adjusting tank 14, and the indoor heat exchanger 13 in sequence, and is then sucked into the compressor 15. Is compressed.

On the other hand, in the heating operation, both the first four-way selection valve 21 and the second four-way selection valve 22 are set to the second state (the state indicated by broken lines in Fig. 9). In the refrigerant circuit 11, the refrigerant is circulated as indicated by the dotted arrows in FIG. That is, the refrigerant discharged from the compressor 15 passes through the indoor heat exchanger 13, the expander 16, the refrigerant adjusting tank 14, and the outdoor heat exchanger 12, and is then sucked into the compressor 15. Is compressed.

[Sixth Embodiment]

A sixth embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant circuit 11 in the air conditioner 10 of the said 5th embodiment. Here, the difference from the said 5th Embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in Fig. 10, in the refrigerant circuit 11 of the present embodiment, the arrangement of the refrigerant adjusting tank 14 is different from that of the fifth embodiment. In this refrigerant circuit 11, the refrigerant adjusting tank 14 is arranged in the middle of the refrigerant flow path from the outdoor heat exchanger 12 and the indoor heat exchanger 13 to the compressor 15 on the side functioning as an evaporator. Specifically, the refrigerant adjusting tank 14 is connected at its upper end to the fourth port of the second four-way selector valve 22 and at its upper end to the suction side of the compressor 15, respectively. As the arrangement of the coolant adjustment tank 14 is changed, the first four-way selection valve 21 has its second port connected to the outlet side of the expander 16.

In the refrigerant circuit 11 of the present embodiment, only the liquid injection pipe 31 and the liquid side control valve 32 are disposed, and the gas injection pipe 33 and the gas side control valve 34 are omitted. In this refrigerant circuit 11, one end of the liquid injection pipe 31 is connected to the bottom of the refrigerant adjusting tank 14, and the other end is connected to the suction side of the compressor 15, respectively. This point is the same as that of the said 5th Embodiment.

Moreover, the controller 90 of this embodiment is comprised so that only the opening degree of the liquid side control valve 32 may be adjusted by omitting the gas injection piping 33 and the gas side control valve 34. The controller 90 sets the target value of the discharged refrigerant temperature of the compressor 15 as the control target value, and the opening degree of the liquid side control valve 32 so that the actual value of the discharged refrigerant temperature of the compressor 15 becomes the control target value. Adjust That is, this controller 90 is configured similarly to the second embodiment.

Operation operation

In the cooling operation, both the first four-way selection valve 21 and the second four-way selection valve 22 are set to the first state (state shown by a solid line in FIG. 10). In the refrigerant circuit 11, the refrigerant is circulated as indicated by the solid arrows in FIG. That is, the refrigerant discharged from the compressor (15) passes through the outdoor heat exchanger (12), the expander (16), the indoor heat exchanger (13), and the refrigerant adjusting tank (14), and is sucked into the compressor (15). Is compressed.

On the other hand, in the heating operation, both the first four-direction selection valve 21 and the second four-direction selection valve 22 are set to the second state (the state indicated by broken lines in Fig. 10). In the refrigerant circuit 11, the refrigerant is circulated as indicated by the dashed arrows in FIG. That is, the refrigerant discharged from the compressor (15) passes through the indoor heat exchanger (13), the expander (16), the outdoor heat exchanger (12), and the refrigerant adjusting tank (14), and is sucked into the compressor (15). Is compressed.

[Seventh Embodiment]

A seventh embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant circuit 11 in the air conditioner 10 of the said 5th embodiment. Here, the difference from the said 5th Embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in FIG. 11, the internal heat exchanger 50 is added to the refrigerant circuit 11 of this embodiment. This internal heat exchanger 50 is comprised similarly to the said 3rd Embodiment. That is, in the internal heat exchanger 50, the first flow path 51 and the second flow path 52 are formed, and the heat transfer area facing the first flow path 51 faces the heat transfer area facing the second flow path 52. Greater than The internal heat exchanger (50) has a first flow path (51) connected between the first port of the second four-way selector valve (22) and the outdoor heat exchanger (12). It is connected between the second port of the direction selector valve 22 and the indoor heat exchanger 13.

Operation operation

At the time of cooling operation, both the first four-way selection valve 21 and the second four-way selection valve 22 are set to the first state (the state shown by the solid line in FIG. 11). In the refrigerant circuit 11, the refrigerant is circulated as indicated by the solid arrows in FIG. That is, the refrigerant flowing out of the outdoor heat exchanger 12 functioning as a gas cooler flows into the expander 16 after passing through the first flow path 51 of the internal heat exchanger 50. The refrigerant flowing out of the indoor heat exchanger 13 functioning as the evaporator is sucked into the compressor 15 after passing through the second flow path 52 of the internal heat exchanger 50.

On the other hand, in the heating operation, both the first four-direction selection valve 21 and the second four-direction selection valve 22 are set to the second state (the state indicated by broken lines in Fig. 11). In the refrigerant circuit 11, the refrigerant is circulated as indicated by the dashed arrows in FIG. That is, the refrigerant flowing out of the indoor heat exchanger 13 functioning as a gas cooler flows into the expander 16 after passing through the second flow path 52 of the internal heat exchanger 50. The refrigerant flowing out of the outdoor heat exchanger 12 functioning as the evaporator is sucked into the compressor 15 after passing through the first flow path 51 of the internal heat exchanger 50.

[Eighth Embodiment]

An eighth embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant circuit 11 and the controller 90 in the air conditioner 10 of the 7th embodiment. Here, the difference from the said 7th Embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in FIG. 12, the 1st solenoid valve 71 and the 2nd solenoid valve 72 are added to the refrigerant circuit 11 of this embodiment. The first solenoid valve 71 is disposed between the second flow path 52 of the internal heat exchanger 50 and the indoor heat exchanger 13. The second solenoid valve 72 is disposed between the first flow path 51 of the internal heat exchanger 50 and the outdoor heat exchanger 12.

In the refrigerant circuit 11, the arrangement of the refrigerant adjusting tank 14 is different from that in the seventh embodiment. In this refrigerant circuit 11, the refrigerant adjusting tank 14 is arranged in the middle of the refrigerant flow path from the outdoor heat exchanger 12 and the indoor heat exchanger 13 to the compressor 15 on the side functioning as an evaporator.

As the arrangement of the refrigerant adjusting tank 14 is changed, the outlet side of the expander 16 is connected to the second port of the first four-way selection valve 21 in the refrigerant circuit 11. In addition, a first inlet tube 63, a second inlet tube 64, and an outlet tube 65 are added to the refrigerant circuit 11.

One end of the first introduction pipe 63 is connected to the upper portion of the refrigerant adjusting tank 14, and the other end is connected between the indoor heat exchanger 13 and the first solenoid valve 71, respectively. The third solenoid valve 73 is disposed in the first inlet tube 63. One end of the second introduction pipe 64 is connected to the upper portion of the refrigerant adjusting tank 14, and the other end thereof is connected between the outdoor heat exchanger 12 and the second solenoid valve 72, respectively. The fourth solenoid valve 74 is disposed in the second introduction pipe 64.

One end of the lead pipe 65 is connected to the top of the coolant adjustment tank 14. The other end of the lead pipe 65 is divided into two, the branched one becomes the first lead branch office 66 and the other leads to the second lead branch engine 67. The first outlet branch pipe 66 is connected between the second flow path 52 of the internal heat exchanger 50 and the first solenoid valve 71. The first check valve 76 is disposed in the first lead branch engine 66. The first check valve 76 permits only refrigerant flow in the direction flowing out of the refrigerant adjustment tank 14. The second outlet branch pipe 67 is connected between the first flow path 51 of the internal heat exchanger 50 and the second solenoid valve 72. The second check valve 77 is disposed in the second outlet branch pipe 67. The second check valve 77 allows only refrigerant flow in the direction flowing out of the refrigerant adjustment tank 14.

In the refrigerant circuit 11 of the present embodiment, only the liquid injection pipe 31 and the liquid side control valve 32 are disposed, and the gas injection pipe 32 and the gas side control valve 34 are omitted. In this refrigerant circuit 11, one end of the liquid injection pipe 31 is connected to the bottom of the refrigerant adjusting tank 14, and the other end is connected to the suction side of the compressor 15, respectively. This point is the same as that of the said 7th Embodiment.

Moreover, the controller 90 of this embodiment is comprised so that only the opening degree of the liquid side control valve 32 may be adjusted by omitting the gas injection piping 33 and the gas side control valve 34. The controller 90 sets the target value of the discharged refrigerant temperature of the compressor 15 as the control target value, and the opening degree of the liquid side control valve 32 so that the actual value of the discharged refrigerant temperature of the compressor 15 becomes the control target value. Adjust That is, this controller 90 is configured similarly to the second embodiment.

In the cooling operation, the second solenoid valve 72 and the third solenoid valve 73 are opened, and the first solenoid valve 71 and the fourth solenoid valve 74 are closed. In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant flowing out of the indoor heat exchanger 13 flows into the refrigerant adjusting tank 14 through the first introduction pipe 63. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the first outlet branch pipe 66, and is sucked into the compressor 15 after passing through the second flow path 52.

On the other hand, in the heating operation, the second solenoid valve 72 and the third solenoid valve 73 are closed, and the first solenoid valve 71 and the fourth solenoid valve 74 are opened. In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant flowing out of the outdoor heat exchanger 12 flows into the refrigerant adjusting tank 14 through the second introduction pipe 64. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the second outlet branch pipe 67, and is sucked into the compressor 15 after passing through the first flow path 51.

First Modified Example of the Eighth Embodiment

In this embodiment, the refrigerant circuit 11 may be configured as follows.

As shown in Fig. 13, in the refrigerant circuit 11 of the present modification, the first to fourth solenoid valves 71 to 74 are omitted, and instead, the first three-way valve 26 and the second three-way valve ( 27) is arranged.

The first three-way valve 26 is disposed in the middle of a pipe connecting the indoor heat exchanger 13 and the second flow path 52 of the internal heat exchanger 50. The first three-way valve 26 has a first port connected to the indoor heat exchanger 13 and a third port connected to the second flow path 52 of the internal heat exchanger 50, respectively. In addition, a first inlet pipe 63 is connected to the second port of the first three-way valve 26.

The second three-way valve 27 is disposed in the middle of the pipe connecting the outdoor heat exchanger 12 and the first flow path 51 of the internal heat exchanger 50. The second three-way valve 27 has a first port connected to the room external heat exchanger 12 and a second port connected to the first flow path 51 of the internal heat exchanger 50, respectively. In addition, a second inlet pipe 64 is connected to the third port of the second three-way valve 27.

At the time of cooling operation, both the first three-way valve 26 and the second three-way valve 27 are set to the state where the first port and the second port communicate (the state shown by the solid line in FIG. 13). In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant flowing out of the indoor heat exchanger 13 flows into the refrigerant adjusting tank 14 through the first introduction pipe 63. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the first outlet branch pipe 66, and is sucked into the compressor 15 after passing through the second flow path 52.

On the other hand, in the heating operation, both the first three-way valve 26 and the second three-way valve 27 are set to the state where the first port and the third port communicate (the state indicated by broken lines in FIG. 13). In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant flowing out of the outdoor heat exchanger 12 flows into the refrigerant adjusting tank 14 through the second introduction pipe 64. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the second outlet branch pipe 67, and is sucked into the compressor 15 after passing through the first flow path 51.

Second Modified Example of the Eighth Embodiment

In this embodiment, the refrigerant circuit 11 may be configured as follows.

As shown in FIG. 14, in the refrigerant circuit 11 of this modification, the 1st-4th solenoid valves 71-74 and the 1st, 2nd check valves 76, 77 are abbreviate | omitted, Instead, the 3rd The four-way selection valve 23 and the fourth four-way selection valve 24 are disposed.

The third four-way selection valve 23 is disposed in the middle of a pipe connecting the indoor heat exchanger 13 and the second flow path 52 of the internal heat exchanger 50. The third four-way selection valve 23 has a first port connected to the indoor heat exchanger 13, and a fourth port connected to the second flow path 52 of the internal heat exchanger 50. In addition, in the third four-way selection valve 23, the first induction branch pipe 66 is connected to the second port, and the first introduction pipe 63 is connected to the third port, respectively.

The fourth four-way selection valve 24 is disposed in the middle of a pipe connecting the outdoor heat exchanger 12 and the first flow path 51 of the internal heat exchanger 50. The fourth four-way selection valve 24 has a first port connected to the outdoor heat exchanger 12 and a third port connected to the first flow path 51 of the internal heat exchanger 50. In the fourth four-way selection valve 24, the second induction branch pipe 67 is connected to the second port, and the second inlet pipe 64 is connected to the fourth port, respectively.

In the cooling operation, not only the first and second four-way selection valves 21 and 22, but also the third and fourth four-way selection valves 23 and 24 are set in the state shown by the solid line in FIG. In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant flowing out of the indoor heat exchanger 13 flows into the refrigerant adjusting tank 14 through the first introduction pipe 63. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the first outlet branch pipe 66, and is sucked into the compressor 15 after passing through the second flow path 52.

On the other hand, in the heating operation, not only the first and second four-way selection valves 21 and 22, but also the third and fourth four-way selection valves 23 and 24 are set in the state shown by broken lines in FIG. In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant flowing out of the outdoor heat exchanger 12 flows into the refrigerant adjusting tank 14 through the second introduction pipe 64. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the second outlet branch pipe 67, and is sucked into the compressor 15 after passing through the first flow path 51.

Third modified example of the eighth embodiment

In this embodiment, the refrigerant circuit 11 may be configured as follows.

As shown in Fig. 15, a third four-way selection valve 23 is added to the refrigerant circuit 11 of this modification. In this refrigerant circuit 11, an introduction tube 60 is disposed instead of the first and second introduction tubes 63 and 64.

In the refrigerant circuit 11, the third four-way selection valve 23 extends from the outdoor heat exchanger 12 to the second four-way selection valve 22 via the first flow path 51 of the internal heat exchanger 50. Is placed in the part. Specifically, the third four-way selector valve 23 has a first port at the other end of the outdoor heat exchanger 12, a second port at the first port of the second four-way selector valve 22, and a third port. The fourth port is connected to one end of the first flow path 51 of the internal heat exchanger 50, and the other end of the first flow path 51 of the internal heat exchanger 50, respectively. In the refrigerant circuit 11, the second solenoid valve 72 is disposed between the fourth port of the third four-way selection valve 23 and the internal heat exchanger 50. Here, also in this refrigerant circuit 11, the second outlet branch pipe 67 is connected between the first flow path 51 and the second solenoid valve 72 of the internal heat exchanger 50.

One end of the introduction pipe 60 is connected to the upper portion of the refrigerant adjusting tank 14. The other end of the introduction pipe 60 branches into two, and the branched one becomes the first introduction branch pipe 61, and the other side becomes the second introduction branch pipe 62. The first inlet branch pipe 61 is connected between the indoor heat exchanger 13 and the first solenoid valve 71. A third solenoid valve 73 is disposed in the first inlet branch pipe 61. The second introduction branch pipe 62 is connected between the fourth port of the third four-way selection valve 23 and the second solenoid valve 72. The 4th solenoid valve 74 is arrange | positioned at this 2nd introduction branch pipe 62.

In the cooling operation, not only the first and second four-way selection valves 21 and 22 but also the third four-way selection valve 23 are set in a state shown by a solid line in FIG. 15, and the second solenoid valve 72. ) And the third solenoid valve 73 are opened and the first solenoid valve 71 and the fourth solenoid valve 74 are closed. In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant flowing out of the indoor heat exchanger 13 flows into the refrigerant adjusting tank 14 through the first introduction branch pipe 61. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the first outlet branch pipe 66, and is sucked into the compressor 15 after passing through the second flow path 52.

In the heating operation, on the other hand, not only the first and second four-way selection valves 21 and 22 but also the third four-way selection valve 23 are set in a state indicated by broken lines in FIG. 15, and the second solenoid valve ( 72 and the third solenoid valve 73 are closed and the first solenoid valve 71 and the fourth solenoid valve 74 are opened. In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant flowing out of the outdoor heat exchanger 12 flows into the refrigerant adjusting tank 14 through the second introduction branch pipe 62. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the second outlet branch pipe 67, and is sucked into the compressor 15 after passing through the first flow path 51.

Fourth modification of the eighth embodiment

In this embodiment, the refrigerant circuit 11 may be configured as follows. In this modification, the configuration of the internal heat exchanger 50 is changed in the second modification (see FIG. 14) of the present embodiment.

As shown in FIG. 16, in the internal heat exchanger 50 of this modification, the 3rd flow path 53 is formed in addition to the 1st flow path 51 and the 2nd flow path 52. As shown in FIG. The internal heat exchanger 50 exchanges the refrigerant of the first flow path 51 and the refrigerant of the second flow path 52 and the heat exchange of the refrigerant of the first flow path 51 and the refrigerant of the third flow path 53. It is composed. In the internal heat exchanger 50, the heat transfer area facing the second flow path 52 is larger than the heat transfer area facing the first flow path 51 or the third flow path 53.

The first flow path 51 of the internal heat exchanger 50 has one end connected to the third port of the fourth four-way selector valve 24 and the other end connected to the first port of the second four-way selector valve 22. Each is connected. In addition, one end of the second flow path 52 of the internal heat exchanger 50 is connected to the fourth port of the second four-way selection valve 22, and the other end is connected to the suction side of the compressor 15, respectively. In addition, one end of the third flow path 53 of the internal heat exchanger 50 is connected to the fourth port of the third four-way selector valve 23, and the other end thereof is the second port of the second four-way selector valve 22. Are connected to each.

In the cooling operation, not only the first and second four-way selection valves 21 and 22 but also the third and fourth four-way selection valves 23 and 24 are set in the state shown by the solid line in FIG. In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant flowing out of the indoor heat exchanger 13 flows into the refrigerant adjusting tank 14 through the first introduction pipe 63. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the first outlet branch pipe 66, and passes through the third flow path 53. The refrigerant passing through the third flow path 53 flows into the second flow path 52 of the internal heat exchanger 50 after that, and is sucked into the compressor 15 after passing through the second flow path 52. The refrigerant flowing out of the outdoor heat exchanger 12 flows into the first flow path 51 of the internal heat exchanger 50, and then flows into the expander 16 after passing through the first flow path 51.

On the other hand, in the heating operation, not only the first and second four-way selection valves 21 and 22, but also the third and fourth four-way selection valves 23 and 24 are set in the state shown by broken lines in FIG. In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant flowing out of the outdoor heat exchanger 12 flows into the refrigerant adjusting tank 14 through the second introduction pipe 64. The gas refrigerant in the refrigerant adjusting tank 14 flows into the internal heat exchanger 50 through the second outlet branch pipe 67 and passes through the first flow path 51. The refrigerant passing through the first flow path 51 flows into the second flow path 52 of the internal heat exchanger 50 after that, and is sucked into the compressor 15 after passing through the second flow path 52. The refrigerant flowing out of the indoor heat exchanger 13 flows into the third flow path 53 of the internal heat exchanger 50, and then flows into the expander 16 after passing through the third flow path 53.

[Ninth Embodiment]

A ninth embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant circuit 11 in the air conditioner 10 of the said 1st Embodiment. Here, the difference from the said 1st Embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in FIG. 17, the internal heat exchanger 50 is added to the refrigerant circuit 11 of this embodiment. The internal heat exchanger 50 includes a first flow path 51 and a second flow path 52, and heat-exchanges the refrigerant in the first flow path 51 and the refrigerant in the second flow path 52. The first flow path 51 of the internal heat exchanger 50 is disposed in the middle of the pipe connecting the second port of the second four-way selection valve 22 and the indoor heat exchanger 13. On the other hand, the second flow path 52 of the internal heat exchanger 50 is arranged in the middle of the pipe connecting the expander 16 with the third port of the second four-way selection valve 22.

Operation operation

In the cooling operation, the coolant circulates in the coolant circuit 11 as indicated by the solid arrows in FIG. 17. At this time, the liquid refrigerant flowing out of the refrigerant adjusting tank 14 flows into the first flow path 51 of the internal heat exchanger 50. The refrigerant flowing out of the outdoor heat exchanger 12 flows into the second flow path 52 of the internal heat exchanger 50. In the internal heat exchanger 50, the refrigerant flowing through the second flow path 52 is cooled by the refrigerant flowing through the first flow path 51. As the expander 16, the refrigerant cooled when passing through the second flow path 52 of the internal heat exchanger 50 is introduced.

On the other hand, during the heating operation, the coolant circulates in the coolant circuit 11 as indicated by the dotted arrows in FIG. At this time, the liquid refrigerant flowing out of the refrigerant adjusting tank 14 flows into the outdoor heat exchanger 12 without passing through the internal heat exchanger 50. The refrigerant flowing out of the indoor heat exchanger 13 passes through the first flow passage 51 of the internal heat exchanger 50 and then flows into the second flow passage 52 of the internal heat exchanger 50. Thus, in the internal heat exchanger 50, heat exchange is hardly performed between the refrigerant in the first flow path 51 and the refrigerant in the second flow path 52. And the refrigerant | coolant which passed the 2nd flow path 52 of the internal heat exchanger flows into the expander 16 as it is when it flowed out from the room heat exchanger 13 substantially.

[Tenth Embodiment]

A tenth embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant | coolant circuit 11 and the controller 90 in the air conditioner 10 of the said 9th embodiment. Here, the difference from the said 9th embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in Fig. 18, in the refrigerant circuit 11 of the present embodiment, the arrangement of the refrigerant adjusting tank 14 is different from that of the ninth embodiment. In this refrigerant circuit 11, the refrigerant adjusting tank 14 is arranged in the middle of the refrigerant flow path from the outdoor heat exchanger 12 and the indoor heat exchanger 13 to the compressor 15 on the side functioning as an evaporator. As the arrangement of the refrigerant adjusting tank 14 is changed, in this refrigerant circuit 11, the outlet side of the expander 16 is connected to the fourth port of the second four-way selection valve 22. In this refrigerant circuit 11, the arrangement of the internal heat exchanger 50 is different from that of the ninth embodiment.

Specifically, the coolant adjustment tank 14 is connected at its lower end to the second port of the first four-way selection valve 21. On the other hand, one end of the first flow path 51 of the internal heat exchanger 50 is connected to the top of the refrigerant adjusting tank 14, and the other end is connected to the suction side of the compressor 15, respectively. Here, the point where the second flow path 52 of the internal heat exchanger 50 is disposed in the middle of the pipe connecting the expander 16 with the third port of the second four-way selection valve 22 is different from that of the ninth embodiment. It is the same.

In the refrigerant circuit 11, a first solenoid valve 81 and a bypass pipe 80 are arranged. The first solenoid valve 81 is disposed between the third port of the second four-way selection valve 22 and the second flow path 52 of the internal heat exchanger 50. The bypass pipe 80 has one end between the second four-way valve 22 and the first solenoid valve 81, and the other end thereof has the second flow path 52 and the expander 16 of the internal heat exchanger 50. Are connected respectively. In this bypass pipe 80, a second solenoid valve 82 is arranged.

In the refrigerant circuit 11 of the present embodiment, only the liquid injection pipe 31 and the liquid side control valve 32 are disposed, and the gas injection pipe 33 and the gas side control valve 34 are omitted. In this refrigerant circuit 11, the liquid injection pipe 31 has one end connected to the bottom of the refrigerant adjusting tank 14 and the other end to the suction side of the compressor 15, respectively. This point is the same as that of the said 1st Embodiment.

Moreover, the controller 90 of this embodiment is comprised so that only the opening degree of the liquid side control valve 32 may be adjusted by omitting the gas injection piping 33 and the gas side control valve 34. The controller 90 sets the discharge refrigerant temperature target value of the compressor 15 as the control target value, and the opening degree of the liquid side control valve 32 so that the actual value of the discharge refrigerant temperature of the compressor 15 becomes the control target value. Adjust That is, this controller 90 is comprised similarly to the thing of said 2nd Embodiment.

Operation operation

In the cooling operation, the first solenoid valve 81 is opened and the second solenoid valve 82 is closed. In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant flowing out of the outdoor heat exchanger 12 flows into the second flow path 52 of the internal heat exchanger 50. The gas refrigerant flowing out of the refrigerant adjusting tank 14 flows into the first flow path 51 of the internal heat exchanger 50. In the internal heat exchanger 50, the refrigerant flowing through the second flow path 52 is cooled by the refrigerant flowing through the first flow path 51. As the expander 16, the refrigerant cooled when passing through the second flow path 52 of the internal heat exchanger 50 is introduced.

On the other hand, in the heating operation, the first solenoid valve 81 is closed and the second solenoid valve 82 is opened. In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant flowing out of the indoor heat exchanger 13 flows into the bypass pipe 80 and flows into the expander 16 without passing through the internal heat exchanger 50. In other words, the refrigerant flowing into the expander 16 remains substantially at the time when it flows out of the indoor heat exchanger 13. The gas refrigerant flowing out of the refrigerant adjusting tank 14 is sucked into the compressor 15 through the first flow path 51 of the internal heat exchanger 50.

Modification of the tenth embodiment

In this embodiment, the refrigerant circuit 11 may be configured as follows.

As shown in Fig. 19, in the refrigerant circuit 11 of the present modification, the arrangement of the internal heat exchanger 50 and the bypass pipe 80 is changed.

One end of the first flow path 51 of the internal heat exchanger 50 is connected to the fourth port of the second four-way selector valve 22 and the other end is connected to the upper portion of the refrigerant adjusting tank 14. Here, the same is true that the second flow path 52 of the internal heat exchanger 50 is disposed in the middle of the pipe connecting the third port of the second four-way selection valve 22 and the expander 16.

In the refrigerant circuit 11 of the present modification, the first solenoid valve 81 is disposed between the first flow path 51 of the internal heat exchanger 50 and the refrigerant adjusting tank 14. In the refrigerant circuit 11, the bypass pipe 80 has one end between the first flow path 51 and the second four-way selector valve 22 of the internal heat exchanger 50, and the other end thereof is the first. It is connected between the solenoid valve 81 and the refrigerant | coolant adjustment tank 14, respectively. The same applies to the fact that the second solenoid valve 82 is disposed in the bypass pipe 80.

In the cooling operation, the first solenoid valve 81 is opened and the second solenoid valve 82 is closed. In the refrigerant circuit 11, the refrigerant circulates as indicated by the solid arrows in FIG. Specifically, the refrigerant flowing out of the outdoor heat exchanger 12 flows into the second flow path 52 of the internal heat exchanger 50. The refrigerant flowing out of the indoor heat exchanger 13 flows into the first flow path 51 of the internal heat exchanger 50. In the internal heat exchanger 50, the refrigerant flowing through the second flow path 52 is cooled by the refrigerant flowing through the first flow path 51. As the expander 16, the cooled refrigerant is introduced when passing through the second flow path 52 of the internal heat exchanger.

On the other hand, in the heating operation, the first solenoid valve 81 is closed and the second solenoid valve 82 is opened. In the refrigerant circuit 11, the refrigerant circulates as indicated by the dashed arrows in FIG. Specifically, the refrigerant flowing out of the outdoor heat exchanger 12 flows into the bypass pipe 80 and is sucked into the compressor 15 without passing through the internal heat exchanger 50. The refrigerant flowing out of the indoor heat exchanger 13 flows into the expander 16 after passing through the second flow path 52 of the internal heat exchanger 50. The refrigerant flowing into the expander 16 remains approximately the same as when it flowed out of the indoor heat exchanger 13.

[Eleventh Embodiment]

An eleventh embodiment of the present invention will be described. The air conditioner 10 of this embodiment changes the structure of the refrigerant circuit 11 in the air conditioner 10 of the said 1st Embodiment. Here, the difference from the said 1st Embodiment is demonstrated about the air conditioner 10 of this embodiment.

As shown in FIG. 20, the heat exchanger 85 is arrange | positioned in the refrigerant circuit 11 of this embodiment. In this refrigerant circuit 11, the heat exchanger 85 is arranged in the middle of a pipe connecting the first port of the second four-way selection valve 22 and the outdoor heat exchanger 12. Moreover, the heat exchanger 85 is accommodated in the refrigerant | coolant adjustment tank 14, and is immersed in the liquid refrigerant in the refrigerant | coolant adjustment tank 14. FIG.

Operation operation

In the cooling operation, the coolant circulates in the coolant circuit 11 as indicated by solid arrows in FIG. At this time, the refrigerant in the gas liquid two-phase state flowing out from the expander 16 flows into the refrigerant adjusting tank 14 to be separated into a liquid refrigerant and a gas refrigerant, and the liquid refrigerant in the refrigerant adjusting tank 14 is converted into an indoor heat exchanger ( 13) is supplied. The refrigerant flowing out of the outdoor heat exchanger 12 flows into the heat exchanger 85 and is cooled by the liquid refrigerant in the refrigerant adjusting tank 14. The refrigerant cooled in the heat exchanger 85 then flows into the expander 16.

On the other hand, during the heating operation, the refrigerant circulates in the refrigerant circuit 11 as indicated by the dashed arrows in FIG. 20. At this time, the refrigerant in the gas liquid two-phase state flowing out of the expander 16 flows into the refrigerant adjusting tank 14 and is separated into a liquid refrigerant and a gas refrigerant. The liquid refrigerant in the refrigerant adjusting tank 14 flows into the outdoor heat exchanger 12 after passing through the heat exchanger 85. In addition, the refrigerant flowing out of the indoor heat exchanger (13) flows into the expander (16).

Other Embodiments

In each said embodiment, the controller 90 may be comprised so that the opening degree of the liquid side control valve 32 or the gas side control valve 34 may be controlled so that the high pressure of a refrigeration cycle may become a predetermined | prescribed target value.

In this case, the controller 90 sets a control target value for the high pressure of the refrigerating cycle. Specifically, the controller 90 acquires the low pressure pressure measured value of the refrigerating cycle and the refrigerant temperature measured value of the gas cooler outlet by a sensor or the like. On the other hand, the controller 90 memorizes in advance the high pressure of the freezing cycle in which the COP of the freezing cycle becomes the highest as a function of the low pressure pressure of the freezing cycle and the refrigerant temperature at the outlet of the gas cooler. At this time, the suction refrigerant state of the compressor 15 is determined in advance, for example, "overheat degree is 5 ° C" or "saturated state". The controller 90 performs calculation by substituting the measured value acquired into this stored function, and sets the value obtained by this as a control target value.

As with the controllers 90 of the first, the fifth, the seventh, the ninth, the eleventh, and the eleventh, the opening degree of the liquid side control valve 32 and the gas side control valve 34 is controlled according to the freezing cycle high pressure. The opening degree of the liquid side control valve 32 or the gas side control valve 34 is adjusted based on the result of the measurement.

For example, it is assumed that the measured value of the refrigerating cycle high pressure is lower than the control target value. At this time, if the gas side control valve 34 is open, the controller 90 tightens the opening degree of the gas side control valve 34. Even when the gas side control valve 34 is fully closed, if the actual value of the compressor 15 discharge refrigerant temperature is still higher than the control target value, the controller 90 increases the opening degree of the liquid side control valve 32. On the contrary, it is assumed that the measured value of the discharge temperature of the compressor 15 is higher than the control target value. At this time, if the liquid side control valve 32 is open, the controller 90 tightens the opening degree of the liquid side control valve 32. If the actual value of the refrigerant 15 discharge refrigerant temperature is still lower than the control target value even when the liquid side control valve 32 is fully closed, the controller 90 increases the opening degree of the gas side control valve 34. .

As with the controllers 90 of the second to fourth, sixth, eighth and tenth embodiments, the opening degree of the liquid side control valve 32 is controlled by comparing the set control target value with the actual measurement value of the refrigerating cycle high pressure. The opening degree of the liquid side control valve 32 is adjusted based on the result.

For example, if the measured value of the refrigerating cycle high pressure is lower than the control target value, the controller 90 increases the opening degree of the liquid side control valve 32. Conversely, if the actual value of the discharge temperature of the compressor 15 is set to be higher than the control target value, the controller 90 increases the opening degree of the gas side control valve 34.

As described above, the present invention is useful for a refrigerating device having the refrigerant circuit 11 to which the expander 16 for power recovery is connected.

Claims (13)

In a refrigerating device including a refrigerant circuit (11) to which a power recovery expander (16) is connected, and a refrigerant cycle is circulated through the refrigerant circuit (11), A refrigerant adjusting tank 14 disposed in the refrigerant flow path from the expander 16 to the compressor 15 of the refrigerant circuit 11 to regulate the amount of refrigerant circulating in the refrigerant circuit 11; A liquid injection passage 31 for supplying the liquid refrigerant in the refrigerant adjusting tank 14 to the suction side of the compressor 15; And a liquid flow rate adjusting mechanism (32) for adjusting the refrigerant flow rate in said liquid injection passage (31). The method according to claim 1, The refrigerant adjusting tank (14) is a refrigeration apparatus disposed downstream of the evaporator in the refrigerant flow path from the expander (16) to the compressor (15). The method according to claim 1, The refrigerant adjusting tank (14) is a refrigeration apparatus disposed in an upstream side of the refrigerant flow path from the expander (16) to the compressor (15). The method according to claim 3, A gas injection passage 33 for supplying the gas refrigerant in the refrigerant adjusting tank 14 to the suction side of the compressor 15, And a gas flow rate control mechanism (34) for controlling the refrigerant flow rate in the gas injection passage (33). The method according to claim 1, 2, 3 or 4, A refrigeration apparatus in which the high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit (11) is set to a value higher than the critical pressure of the refrigerant. The method according to claim 1, 2 or 3, The high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant, And a control means (90) for operating the liquid flow rate adjusting mechanism (32) so that the temperature of the refrigerant discharged from the compressor (15) becomes a predetermined control target value. The method according to claim 4, The high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant, And a control means (90) for operating the liquid flow rate adjusting mechanism (32) and the gas flow rate adjusting mechanism (34) so that the temperature of the refrigerant discharged from the compressor (15) becomes a predetermined control target value. The method according to claim 1, 2 or 3, The high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant, And a control means (90) for manipulating the liquid flow rate adjusting mechanism (32) such that the high pressure of the refrigeration cycle made in said refrigerant circuit (11) becomes a predetermined control target value. The method according to claim 4, The high pressure of the refrigerating cycle performed by circulating the refrigerant in the refrigerant circuit 11 is set to a value higher than the critical pressure of the refrigerant, And a control means (90) for operating the liquid flow rate regulation mechanism (32) and the gas flow rate regulation mechanism (34) so that the high pressure of the refrigeration cycle made by the refrigerant circuit (11) becomes a predetermined control target value. The method according to claim 6, The control means 90 is configured to set the control target value based on the operating state of the freezing cycle so that the resultant coefficient of the freezing cycle in the refrigerant circuit 11 is the highest value obtained in the operating state at that time. . The method according to claim 7 or 9, The control means 90 is configured to set the control target value based on the operating state of the freezing cycle so that the resultant coefficient of the freezing cycle in the refrigerant circuit 11 is the highest value obtained in the operating state at that time. . The method according to claim 8, The control means 90 is configured to set the control target value based on the operating state of the freezing cycle so that the resultant coefficient of the freezing cycle in the refrigerant circuit 11 is the highest value obtained in the operating state at that time. . The method according to claim 5, A refrigeration apparatus in which the refrigerant circuit (11) is filled with carbon dioxide as a refrigerant.

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