JP4930214B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a vapor compression refrigeration cycle apparatus including a plurality of compressors and an internal heat exchanger.

  Conventionally, in Patent Document 1, a first compressor that is applied to a refrigerated vehicle and is driven by an engine for running a vehicle, a second compressor that is driven by an electric motor, and a high-pressure refrigerant that has flowed out of a radiator A refrigeration cycle apparatus including an internal heat exchanger for exchanging heat between the low-pressure refrigerant flowing out of the evaporator is disclosed.

  In the refrigeration cycle apparatus of Patent Document 1, a first compressor and a second compressor are connected in parallel, and only the first compressor is driven when the engine is operating, and only the second compressor is driven when the engine is stopped. The interior of the compartment and the passenger compartment can be cooled even when the engine is stopped.

Furthermore, the internal heat exchanger exchanges heat between the high-pressure refrigerant flowing out of the radiator and the low-pressure refrigerant flowing out of the evaporator, thereby reducing the enthalpy difference (refrigeration capacity) of the refrigerant between the refrigerant inlet and outlet in the evaporator. The coefficient of performance (COP) of the refrigeration cycle is improved by increasing the value.
JP 2006-273150 A

  By the way, in the refrigeration cycle apparatus including the engine-driven first compressor and the electric second compressor as in the refrigeration cycle apparatus of Patent Document 1, generally, the refrigerant discharge capacity of each compressor is different. . Therefore, the refrigerating capacity that can be exhibited in the first operation mode that drives only the first compressor is different from the refrigerating capacity that can be exhibited in the second operation mode that drives only the second compressor.

  Therefore, for example, in the first operation mode for driving the first compressor capable of obtaining sufficient driving force from the engine, a high-load operation is performed so that the interior is cooled rapidly, and the engine-driven compressor is generally used. On the other hand, in the second operation mode in which the electric second compressor having a small refrigerant discharge capacity is driven, a low load operation is performed so as to keep the inside of the refrigerator cold. Therefore, the heat load conditions of the cycle are different between the first operation mode and the second operation mode.

  Therefore, in the first and second operation modes, the specifications and performances of the cycle constituent devices required for appropriately operating the cycle are also different. On the other hand, in the refrigeration cycle apparatus of Patent Document 1, since the air flow rate for heat exchange with the refrigerant can be adjusted for the radiator or the evaporator, the cycle is appropriately operated in any operation mode. You can control its performance as you can.

  However, the internal heat exchanger is simply configured to exchange heat between the high-pressure refrigerant that has flowed out of the radiator and the low-pressure refrigerant that has flowed out of the evaporator, so its performance can be controlled according to the operation mode. Cannot be done (see paragraph 0023 in FIG. 2 of Patent Document 1). For this reason, due to the change in the operation mode, proper heat exchange cannot be performed in the internal heat exchanger, and the cycle may not be properly operated.

  For example, when the driving power of the compressor increases as in high load operation, if the amount of heat exchange in the internal heat exchanger is insufficient, the degree of supercooling flowing into the decompression means (expansion valve) decreases. . Therefore, the refrigerant enthalpy difference between the refrigerant inlet and outlet in the evaporator cannot be sufficiently increased, and the COP cannot be sufficiently improved.

  On the other hand, if the degree of superheat of the refrigerant on the downstream side of the evaporator tends to be small, such as during low-load operation, if the amount of heat exchange in the internal heat exchanger increases unnecessarily, it flows into the decompression means (expansion valve) The supercooling degree of the high-pressure refrigerant to be increased will unnecessarily increase. As a result, the refrigerating capacity cannot be exhibited in the evaporator.

  This will be described with reference to the Mollier diagram of FIG. The solid line in FIG. 9 shows the state of the refrigerant when the degree of supercooling of the high-pressure refrigerant flowing into the pressure reducing means is an appropriate value, and the broken line in FIG. 9 is the degree of supercooling of the high-pressure refrigerant flowing into the pressure reducing means. The state of the refrigerant | coolant when has increased unnecessarily is shown. In addition, each code | symbol shown with the alphabet of FIG. 9 respond | corresponds to the state of the refrigerant | coolant of each code | symbol shown with the same alphabet of FIG. 2 mentioned later.

As shown in solid line in FIG. 9, if the high-pressure refrigerant flowing into the pressure reducing means is in the liquid phase refrigerant of suitable supercooling degree (C ₉ points in FIG. 9), an amount corresponding enthalpy decrease amount [Delta] H ₉ The refrigeration capacity that can be exhibited in the evaporator can be expanded.

On the other hand, as shown by the broken line in FIG. 9, when the high-pressure refrigerant flowing into the decompression means is a liquid-phase refrigerant having a degree of supercooling more than necessary (point C ₉ ′ in FIG. 9), the control of the decompression means The range is exceeded, and the decompression means cannot sufficiently decompress the high-pressure refrigerant. That is, even if the high-pressure refrigerant is decompressed and expanded by the decompression means, the high-pressure refrigerant does not change to a gas-liquid two-phase refrigerant and flows into the low-pressure side (evaporator) as the liquid-phase refrigerant.

  At this time, since the liquid-phase refrigerant has a much higher density than the gas-liquid two-phase refrigerant, a large amount of refrigerant flows into the low-pressure side (evaporator). If all of the liquid-phase refrigerant that has flowed in a large amount by the evaporator cannot be evaporated, the liquid-phase refrigerant or the gas-liquid two-phase refrigerant will flow into the low-pressure side refrigerant flow path of the internal heat exchanger.

  Furthermore, if the gas-liquid two-phase refrigerant flows into the low-pressure side refrigerant flow path of the internal heat exchanger, the internal heat exchanger causes heat exchange between the high-pressure liquid refrigerant and the low-pressure two-phase refrigerant. Compared with heat exchange between a single-phase refrigerant and a single-phase low-pressure gas-phase refrigerant, the heat transfer coefficient is increased by an order of magnitude (10 times or more), and the degree of supercooling of the high-pressure refrigerant flowing into the decompression means is increased. End up.

  As a result, a larger amount of refrigerant flows into the low pressure side (evaporator) and increases the refrigerant evaporation pressure in the evaporator. And if the refrigerant | coolant evaporation temperature in an evaporator becomes higher than the temperature of space for cooling with the raise of this refrigerant | coolant evaporation pressure, it will become impossible to exhibit the refrigerating capacity in an evaporator.

  In view of the above-mentioned points, the present invention allows a refrigeration cycle apparatus including a plurality of compressors and an internal heat exchanger to perform appropriate heat exchange in the internal heat exchanger even if the heat load condition of the cycle changes. With the goal.

In order to achieve the above object, the first aspect of the present invention provides a first compressor (11) that compresses and discharges a refrigerant, and is connected in parallel to the first compressor (11). A second compressor (12) that compresses and discharges, a radiator (15) that dissipates heat from the refrigerant discharged from the first compressor (11) and the refrigerant discharged from the second compressor (12), and heat dissipation (15) A refrigeration cycle comprising decompression means (18, 30) for decompressing and expanding the downstream refrigerant and evaporators (19, 34) for evaporating the refrigerant decompressed and expanded by the decompression means (18, 30) A device,
The first compressor (11) is an engine-driven compressor that obtains driving force from the engine,
The second compressor (12) is an electric compressor that obtains driving force from the electric motor (12a),
The maximum refrigerant discharge capacity of the second compressor (12) is smaller than the maximum refrigerant discharge capacity of the first compressor (11),
Furthermore, the heat exchanger (15) includes an internal heat exchanger (17, 20) for exchanging heat between the high-pressure refrigerant on the downstream side and the low-pressure refrigerant on the downstream side of the evaporator (19, 34), and the internal heat exchanger (17, 20). ) Heat exchange so that the heat exchange amount in the first operation mode for driving only the first compressor (11) is larger than the heat exchange amount in the second operation mode for driving only the second compressor (12). It is characterized by making it.

  According to this, heat exchange is performed so that the heat exchange amount in the first operation mode of the internal heat exchanger (17, 20) is larger than the heat exchange amount in the second operation mode. By performing load operation and applying to a cycle in which low load operation is performed in the second operation mode, it is possible to cause the internal heat exchangers (17, 20) to perform appropriate heat exchange in each operation mode.

  That is, when the driving power of the compressor increases as in a high load operation, the high-pressure refrigerant flows into the decompression means (18, 30) by increasing the heat exchange amount in the internal heat exchanger (17, 20). The degree of supercooling of the refrigerant can be increased to increase the refrigerant enthalpy difference between the refrigerant inlet and outlet in the evaporator (19, 34). As a result, COP can be sufficiently improved.

  On the other hand, when the degree of superheat of the refrigerant on the downstream side of the evaporator (19, 34) tends to be small, such as during low load operation, the amount of heat exchange in the internal heat exchanger (17, 20) is reduced to reduce the pressure reduction means ( 18 and 30), it is possible to suppress an unnecessary increase in the degree of supercooling of the high-pressure refrigerant. As a result, it can be avoided that the refrigerating capacity cannot be exhibited in the evaporator (19, 34).

  That is, according to the refrigeration cycle apparatus having the above characteristics, even if the first operation mode and the second operation mode are switched according to the change in the heat load condition of the cycle, the internal heat exchanger (17, 20) Appropriate heat exchange can be performed and the cycle can operate properly.

Further, as in the invention described in claim 2, in the refrigeration cycle apparatus described in claim 1, the flow of the refrigerant flowing out of the evaporator (19, 34) is branched, and one of the branched low-pressure refrigerants is changed. A branch portion (14) for guiding the other low-pressure refrigerant branched to the suction port side of the first compressor (11) and leading to the suction port side of the second compressor (12) is provided, and an internal heat exchanger (17 20), at least part of the low-pressure side refrigerant flow paths (17b, 21b, 22b) is such that only the refrigerant that has flowed out from the branching section (14) to the suction side of the first compressor (11) flows. It may be.

According to this, the heat exchange amount in the first operation mode of the internal heat exchanger (17, 20) can be easily made larger than the heat exchange amount in the second operation mode.
In the invention according to claim 3, the first compressor (11) that compresses and discharges the refrigerant, and the second compressor (11) that is connected in parallel to the first compressor (11) and compresses and discharges the refrigerant. A compressor (12), a radiator (15) for dissipating the refrigerant discharged from the first compressor (11) and the refrigerant discharged from the second compressor (12), and a radiator (15) downstream A refrigeration cycle apparatus comprising: decompression means (18, 30) for decompressing and expanding the refrigerant; and evaporators (19, 34) for evaporating the refrigerant decompressed and expanded by the decompression means (18, 30),
Furthermore, an internal heat exchanger (17, 20) for exchanging heat between the high-pressure refrigerant downstream of the radiator (15) and the low-pressure refrigerant downstream of the evaporator (19, 34);
The flow of the refrigerant flowing out of the evaporator (19, 34) is branched, one branched low-pressure refrigerant is guided to the inlet side of the first compressor (11), and the other branched low-pressure refrigerant is supplied to the first refrigerant (11). A bifurcation (14) leading to the suction port side of the compressor (12),
At least a part of the low-pressure side refrigerant flow path (17b, 21b, 22b) of the internal heat exchanger (17, 20) is only the refrigerant that has flowed out from the branch part (14) to the first compressor (11) inlet side. Are now in circulation,
The internal heat exchanger (17, 20) has a heat exchange amount in the second operation mode in which the heat exchange amount in the first operation mode for driving only the first compressor (11) drives only the second compressor (12). The heat exchange is performed so as to increase the amount.
In the invention according to claim 3, as in the invention according to claim 1, in the first operation mode and the second operation mode, appropriate heat exchange is performed by the internal heat exchanger (17, 20). , You can drive the cycle properly.
Moreover, by providing the said branch part (14), it is easily achieved that the heat exchange amount in the first operation mode of the internal heat exchanger (17, 20) is larger than the heat exchange amount in the second operation mode. it can.

Further, as in the invention according to claim 4, in the refrigeration cycle apparatus according to claim 1 , at least of the high-pressure side refrigerant flow paths (17a, 21a, 22a) of the internal heat exchanger (17, 20). A bypass passage (23) for partially bypassing and an opening / closing means (24, 25) for opening and closing the bypass passage (23) are provided, and the opening / closing means (24, 25) is a bypass passage (23) in the first operation mode. closed, in the second operation mode may be adapted to open the bypass passage (23).

  According to this, the heat exchange amount in the first operation mode of the internal heat exchanger (17, 20) can be easily made larger than the heat exchange amount in the second operation mode.

Further, as in the invention described in claim 5, in the refrigeration cycle apparatus described in claim 1 , at least of the high-pressure side refrigerant flow paths (17a, 21a, 22a) of the internal heat exchanger (17, 20). A bypass passage (23) for bypassing a part, a high-pressure side refrigerant flow path (17a, 21a, 22a), and a flow rate adjusting valve (26) for adjusting the flow rate of refrigerant flowing into the bypass passage (23) side are provided. The regulating valve (26) adjusts the refrigerant flow rate that flows into the high-pressure side refrigerant flow path (17a, 21a, 22a) in the first operation mode, and the high-pressure side refrigerant flow path (17a, 21a, 22a) in the second operation mode. The refrigerant flow rate may be increased more than the refrigerant flow rate.

  According to this, the heat exchange amount in the first operation mode of the internal heat exchanger (17, 20) can be easily made larger than the heat exchange amount in the second operation mode.

Further, as in the invention described in claim 6, in the refrigeration cycle apparatus described in claim 3 , the first compressor (11) is an engine-driven compressor that obtains driving force from the engine, and the second compression The machine (12) may be an electric compressor that obtains driving force from the electric motor (12a).

In general, the maximum refrigerant discharge capacity of an engine-driven compressor is higher than the maximum refrigerant discharge capacity of an electric compressor. Therefore, the refrigeration according to claim 3 is performed by performing a high load operation using the first compressor (11) as an engine driven compressor and performing a low load operation using the second compressor (12) as an electric compressor. The effect by the cycle device can be obtained effectively.

Moreover, in the refrigeration cycle apparatus according to any one of claims 1 to 6, as in the invention described in claim 7 , the decompression means is a high pressure jetted from the nozzle portion (30a) that decompresses and expands the high-pressure refrigerant. It may be configured by an ejector (30) that sucks the refrigerant into the inside by a high-speed refrigerant flow, and mixes the sucked refrigerant and the high-speed refrigerant flow to increase the pressure.

According to the seventh aspect of the invention, since it is possible to prevent the degree of supercooling of the refrigerant flowing into the ejector (30) serving as the pressure reducing means from increasing unnecessarily, the amount of recovered energy in the ejector (30) can be reduced. Reduction can be suppressed. As a result, COP can be effectively increased.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the refrigeration cycle apparatus 10 of the present invention is applied to a refrigeration vehicle. In addition, a refrigeration vehicle is a vehicle provided with the freezer compartment which preserve | saves cooling objects, such as a foodstuff, at the extremely low temperature of about -30-30 degreeC.

  First, the configuration of the refrigeration cycle apparatus 10 of the present embodiment will be described with reference to the overall configuration diagram of FIG. The refrigeration cycle apparatus 10 has two compressors that suck in refrigerant, compress it, and discharge it. Of these, the first compressor 11 is an engine-driven compressor that obtains rotational driving force from a vehicle travel engine (not shown) via an electromagnetic clutch, a belt, and the like.

  The first compressor 11 is a variable capacity compressor that can adjust the refrigerant discharge capacity by changing the discharge capacity, or a fixed that can adjust the refrigerant discharge capacity by changing the operating rate of the compressor operation by intermittently connecting the electromagnetic clutch. Any of the capacity type compressors may be adopted.

  On the other hand, the second compressor 12 is an electric compressor that obtains rotational driving force from the electric motor 12a. The maximum refrigerant discharge capacity of the second compressor 12 is smaller than the maximum refrigerant discharge capacity of the first compressor 11. The electric motor 12a is supplied with electric power from a vehicle battery (not shown), and can be supplied from an external power source (commercial power source) when the vehicle is stopped.

  Furthermore, as shown in FIG. 1, the first compressor 11 and the second compressor 12 are connected in parallel by connecting the discharge sides to each other by a merging portion 13 and connecting the suction sides to each other by a branch portion 14. It is connected. The merge portion 13 and the branch portion 14 can be configured by a pipe joint having a three-way joint structure.

  More specifically, the merge portion 13 has two refrigerant inlets 13a and 13b and one refrigerant outlet 13c, and the two refrigerant inlets 13a and 13b are respectively in the first and second first compressions. It is connected to the discharge side of the machines 11 and 12. Moreover, the branch part 14 has one refrigerant inlet 14a and two refrigerant outlets 14b and 14c, and the two refrigerant outlets 14b and 14c are the first and second compressors 11 and 12, respectively. Connected to the inhalation side.

  Further, the first check valve 11b and the second check valve 11b allow the refrigerant to flow only in the discharge direction between the discharge port of the first compressor 11 and the discharge port of the second compressor 12 and the junction 13 respectively. A check valve 12b is provided. This prevents the refrigerant discharged from one compressor from flowing back into the other compressor via the refrigerant discharge port.

  A radiator 15 is connected to the refrigerant outlet 13 c of the junction 13. This radiator 15 is a heat exchanger for heat radiation that cools the high-pressure refrigerant by exchanging heat between the high-pressure refrigerant discharged from the first compressor 11 and the outside air blown from the electric blower 15a. The electric blower 15a is configured to rotate a known centrifugal multiblade fan with an electric motor.

  Note that the refrigeration cycle apparatus 10 of the present embodiment employs a normal chlorofluorocarbon refrigerant as the refrigerant, and constitutes a subcritical cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. Therefore, the radiator 15 functions as a condenser that condenses the refrigerant.

  A receiver 16 is connected to the outlet side of the radiator 15. The receiver 16 is a gas-liquid separator that separates the gas-liquid refrigerant flowing out of the radiator 15 and stores the liquid-phase refrigerant. Further, the high-pressure side refrigerant flow path 17 a of the internal heat exchanger 17 is connected to the liquid-phase refrigerant outlet of the receiver 16.

  The internal heat exchanger 17 passes through the high-pressure refrigerant on the downstream side of the radiator 15 that passes through the high-pressure side refrigerant flow path 17a (specifically, the liquid-phase refrigerant that has flowed out of the receiver 16) and the low-pressure side refrigerant flow path 17b. The high-pressure refrigerant is cooled by exchanging heat with a low-pressure refrigerant on the downstream side of the evaporator 19 (specifically, a gas-phase refrigerant that has flowed out from the branching section 14 to the suction side of the first compressor 11).

  Thereby, the enthalpy difference (refrigeration capacity) of the refrigerant | coolant between the refrigerant | coolant inlet_port | entrance and outlet in the evaporator 19 can be increased, and the coefficient of performance (COP) of a refrigerating cycle can be improved. Note that the internal heat exchanger 17 of the present embodiment is configured so that the high-pressure refrigerant flowing out from the high-pressure side refrigerant passage 17a has an appropriate supercooling degree in order to improve COP in the first operation mode described later. The exchange capacity has been adjusted.

  Further, as a specific configuration of the internal heat exchanger 17, the refrigerant pipes forming the high-pressure side refrigerant flow path 17a and the low-pressure side refrigerant flow path 17b are joined together by a joining means such as brazing, welding, pressure welding, or soldering. Thus, it is possible to adopt a configuration in which heat is exchanged through the joint surface, a double-tube heat exchanger configuration in which the low-pressure side refrigerant flow path 17b is disposed inside the outer pipe that forms the high-pressure side refrigerant flow path 17a, and the like.

  A well-known temperature expansion valve 18 that is a decompression means is connected to the outlet side of the high-pressure side refrigerant flow path 17a of the internal heat exchanger 17. The temperature type expansion valve 18 has a temperature sensing part 18 a disposed on the outlet side of the evaporator 19, and based on the temperature and pressure of the refrigerant on the outlet side of the evaporator 19, the refrigerant on the outlet side of the evaporator 19 is overheated. The valve opening degree (refrigerant flow rate) is adjusted so that the degree of superheat of the refrigerant on the outlet side of the evaporator 19 becomes a predetermined value.

  An evaporator 19 is connected to the downstream side of the temperature type expansion valve 18. The evaporator 19 evaporates the low-pressure refrigerant and exhibits an endothermic effect by exchanging heat between the low-pressure refrigerant passing through the interior and the air in the freezer that is the cooling target space circulated and blown from the electric blower 19a. This is an endothermic heat exchanger. The basic configuration of the electric blower 19a is the same as that of the electric blower 15a.

  On the outlet side of the evaporator 19, the refrigerant inlet 14 a of the branch portion 14 is connected. Of the two refrigerant outlets of the branching section 14, one refrigerant outlet 14 b is connected to the suction side of the first compressor 11 via the low-pressure side refrigerant passage 17 a of the internal heat exchanger 17. Yes. Further, the other refrigerant outlet 14 c is directly connected to the refrigerant inlet of the second compressor 12.

  Therefore, in the internal heat exchanger 17 of the present embodiment, only the refrigerant that has flowed out from the branch portion 14 to the suction port side of the first compressor 11 flows in all the portions of the low-pressure side refrigerant flow path 17a.

  Next, the operation of the present embodiment in the above configuration will be described with reference to the Mollier diagram of FIG. Note that the refrigeration cycle apparatus 10 of the present embodiment has two operation modes of first and second operation modes, and the solid line in FIG. 2 indicates the state of the refrigerant in the first operation mode, and the broken line in FIG. Indicates the state of the refrigerant in the second operation mode.

  First, the first operation mode is an operation mode in which only the first compressor 11 is driven. Therefore, the first operation mode is executed only when the vehicle travel engine is operated. Further, in the first operation mode, since the first compressor 11 can obtain a sufficient rotational driving force from the vehicle running engine, a high load operation in which the heat load of the refrigeration cycle apparatus 10 is higher than the normal operation is performed. .

  Note that high-load operation is, for example, an operation in which the inside of the warehouse is rapidly cooled, such as when a high-temperature object to be cooled is placed in the warehouse, or when the outside air temperature is high as in the summer. is there. Specifically, target temperature setting means for setting the target temperature in the storage and temperature detection means for measuring the actual internal temperature are provided, and the difference between the actual internal temperature and the target internal temperature is a predetermined temperature (for example, When the temperature is higher than 5 ° C., a high load operation may be performed.

In the first operation mode, the high-pressure refrigerant (point A _{1 in} FIG. 2) discharged from the first compressor 11 flows into the radiator 15 through the junction 13. High-pressure refrigerant flowing into the radiator 15, and the outdoor air heat exchanger that has been blown from the electric blower 15a is cooled and separated into gas and liquid in the receiver 16 (A ₁ point in FIG. 2 → B ₁ point).

The high-pressure liquid-phase refrigerant flowing out of the receiver 16 flows into the high-pressure side refrigerant flow path 17a of the internal heat exchanger 17 and exchanges heat with the low-pressure refrigerant flowing through the low-pressure side refrigerant flow path 17b, thereby reducing enthalpy. It is not a supercooled state (B ₁ point of FIG. 2 → C ₁ point). At this time, since the heat exchange capability of the internal heat exchanger 17 is adjusted as described above, the degree of supercooling of the high-pressure refrigerant flowing out from the high-pressure side refrigerant flow path 17a becomes an appropriate value for improving COP.

High pressure liquid refrigerant flowing out from the high-pressure side refrigerant flow path 17a of the internal heat exchanger 17 flows is isenthalpic depressurize and expanded by the thermal expansion valve 18 to the evaporator 19 (C ₁ point in FIG. 2 → D ₁ point). In the evaporator 19, the low-pressure refrigerant absorbs heat from the inside air circulated by the electric blower 19 a and evaporates (D ₁ point → E ₁ point in FIG. 2). Thereby, the air sent into the warehouse is cooled.

The refrigerant that has flowed out of the evaporator 19 passes through the branch portion 14, passes through the low-pressure side refrigerant flow path 17 b of the internal heat exchanger 17, and is sucked into the first compressor 11 again (point E _{1 in} FIG. 2). → F ₁ point).

Since the first operation mode operates as described above, when the driving power of the first compressor 11 increases as in a high-load operation, the internal heat exchanger 17 causes the temperature-type expansion valve 18 to operate. The degree of supercooling of the inflowing high-pressure refrigerant can be increased. As a result, the enthalpy difference of the refrigerant between the refrigerant inlet and outlet in the evaporator 19 can be increased by ΔH ₁ in FIG. 2 to improve COP.

  Next, the second operation mode is an operation mode in which only the second compressor 12 is driven. Therefore, the second operation mode can be executed not only when the vehicle running engine is operated but also when the vehicle is stopped. As described above, since the maximum refrigerant discharge capacity of the second compressor 12 is smaller than the maximum refrigerant discharge capacity of the first compressor 11, the heat load of the refrigeration cycle apparatus 10 is equal to or lower than the normal operation in the second operation mode. Low load operation is performed.

  The low-load operation is an operation that performs, for example, cold storage in a warehouse. Specifically, the case where the difference between the actual internal temperature and the target internal temperature is equal to or lower than a predetermined temperature (for example, 5 ° C.) may be set as the low load operation. Therefore, in the present embodiment, the normal operation is also included in the low load operation.

In the second operation mode, the high-pressure refrigerant discharged from the second compressor 12 (A ₂ points in FIG. 2) is, similarly to the first operation mode, through the confluence section 13, flows into the radiator 15, It flows in the order of the receiver 16 → the high-pressure side refrigerant flow path 17 a of the internal heat exchanger 17 → the temperature type expansion valve 18 → the evaporator 19. (A ₂ point → C ₂ point → D ₂ point in FIG. 2).

Then, the low-pressure refrigerant flowing out of the evaporator 19 is directly sucked into the second compressor 12 from the refrigerant outlet 14b of the branch portion 14 without passing through the low-pressure side refrigerant flow path 17b of the internal heat exchanger 17 ( (D ₂ point → F ₂ point in FIG. 2). Therefore, in the internal heat exchanger 17, heat exchange between the high-pressure refrigerant and the low-pressure refrigerant is not performed, and the high-pressure side refrigerant flow path 17a functions as a simple refrigerant passage.

  In the second operation mode, since it operates as described above, even when the degree of superheat of the refrigerant on the downstream side of the evaporator 19 tends to be small as in low load operation, the refrigerant flows out of the receiver 16 into the temperature type expansion valve 18. A saturated liquid phase refrigerant can be introduced. As a result, it is possible to prevent the supercooling degree of the high-pressure refrigerant flowing into the temperature type expansion valve 18 from increasing unnecessarily, and to reliably exhibit the refrigeration capacity in the evaporator 19.

  As described above, according to the refrigeration cycle apparatus 10 of the present embodiment, even if the first operation mode and the second operation mode are switched according to the change in the heat load condition of the cycle, the internal heat exchanger 17 Appropriate heat exchange can be performed. Therefore, even if the heat load condition of the cycle changes, the cycle can be appropriately operated.

(Second Embodiment)
In the first embodiment, the internal heat exchanger 17 is adopted. However, in the present embodiment, as shown in the overall configuration diagram of FIG. 3, two heat exchanges of the first heat exchange unit 21 and the second heat exchange unit 22 are performed. An internal heat exchanger 20 configured with a portion is employed. In FIG. 3, the same or equivalent parts as those in the first embodiment are denoted by the same reference numerals. The same applies to the following drawings.

  The basic configuration of the first and second heat exchange units 21 and 22 of the internal heat exchanger 20 is the same as that of the internal heat exchanger 17 of the first embodiment. Accordingly, the first heat exchange unit 21 is provided with the first high-pressure side refrigerant flow path 21a and the first low-pressure side refrigerant flow path 21b, and the second heat exchange unit 22 is provided with the second high-pressure side refrigerant flow path 22a and A second low-pressure side refrigerant flow path 22b is provided.

  That is, the high-pressure side refrigerant flow path of the internal heat exchanger 20 is configured by the first high-pressure side refrigerant flow path 21a and the second high-pressure side refrigerant flow path 22a, and the low-pressure side refrigerant flow path is the first low-pressure side refrigerant flow path. 21b and the second low-pressure side refrigerant flow path 22b.

  Next, the connection relationship of the internal heat exchanger 20 will be described. In the present embodiment, the liquid-phase refrigerant outlet of the receiver 16 is connected to the inlet side of the first high-pressure side refrigerant flow path 21a, and the first high-pressure side refrigerant flow path 21a → second high-pressure side refrigerant flow path 22a → temperature-type expansion. The valves 18 are connected in this order.

  Further, the outlet side of the evaporator 19 is connected to the refrigerant inlet 14 a of the branch portion 14 via the second low-pressure side refrigerant flow path 22 b of the second heat exchange unit 22. Further, the refrigerant outlet 14 b of the branching section 14 is connected to the suction side of the first compressor 11 via the first low-pressure side refrigerant flow path 21 b of the first heat exchange section 21.

  That is, in the internal heat exchanger 20 of the present embodiment, the suction of the first compressor 11 from the branch portion 14 into a part of the low-pressure side refrigerant flow path (specifically, the first low-pressure side refrigerant flow path 21b). Only the refrigerant that has flowed out to the mouth side circulates. Other configurations are the same as those of the first embodiment.

  Therefore, when the refrigeration cycle apparatus 10 according to the present embodiment is operated, in the first operation mode, the high-pressure refrigerant flows in the order of the first high-pressure side refrigerant flow path 21a → the second high-pressure side refrigerant flow path 22a, and the low-pressure refrigerant is the second. The low-pressure side refrigerant flow path 22b flows in the order of the first low-pressure side refrigerant flow path 21b. That is, in the internal heat exchanger 20, heat exchange is performed in both the first and second heat exchange units 21 and 22.

  As a result, similar to the first embodiment, the COP can be improved by increasing the degree of supercooling of the high-pressure refrigerant flowing into the temperature type expansion valve 18 during high load operation.

  On the other hand, in the second operation mode, the high-pressure refrigerant flows in the order of the first high-pressure side refrigerant flow path 21a → the second high-pressure side refrigerant flow path 22a, and the low-pressure refrigerant flows only in the second low-pressure side refrigerant flow path 22b. That is, in the internal heat exchanger 20, heat exchange is performed only in the second heat exchange unit 22.

  Therefore, in the second operation mode, compared to the first operation mode, the amount of heat exchange in the internal heat exchanger 20 is reduced, and the degree of supercooling of the high-pressure refrigerant flowing into the temperature type expansion valve 18 is unnecessarily increased. Can be suppressed. As a result, the evaporator 19 can appropriately exhibit the refrigerating capacity.

  As described above, even in the refrigeration cycle apparatus 10 according to the present embodiment, even if the first operation mode and the second operation mode are switched according to the change in the heat load condition of the cycle, the internal heat exchanger 20 is appropriate. Heat exchange can be performed.

(Third embodiment)
This embodiment is different from the first embodiment in that the bypass passage 23 for bypassing the high-pressure side refrigerant passage 17a of the internal heat exchanger 17 and the bypass passage 23 are opened and closed as shown in the overall configuration diagram of FIG. In addition to providing the 1, 2 on-off valves 24 and 25, the connection relation of the low-pressure side refrigerant flow path 17b of the internal heat exchanger 17 is changed.

  Specifically, the bypass passage 23 is a refrigerant passage that directly connects the liquid-phase refrigerant outlet of the receiver 16 and the inlet side of the temperature type expansion valve 18. Therefore, the bypass passage 23 of the present embodiment bypasses the entire high-pressure side refrigerant flow path 17a of the high internal heat exchanger 17.

  The first on-off valve 24 is a so-called normally closed electromagnetic valve that is disposed in the bypass passage 23 and opens when energized and closes when de-energized. The second on-off valve 25 is arranged between the outlet side of the internal heat exchanger 17 and the outlet side connection part of the bypass passage 23, and closes when energized, and opens when not energized, so-called normally open type. It is a solenoid valve. The first and second on-off valves 24 and 25 are controlled to open and close by a control device (not shown).

  The outlet side of the evaporator 19 is connected to the refrigerant inlet 14 a of the branch portion 14 via the low-pressure side refrigerant flow path 17 b of the internal heat exchanger 17. Other configurations are the same as those of the first embodiment.

  Next, the operation of this embodiment will be described. In the first operation mode, the control device puts the first and second on-off valves 24 and 25 into a non-energized state. That is, the first on-off valve 24 is closed and the second on-off valve 25 is opened. Therefore, in the first operation mode, the high-pressure refrigerant passes through the high-pressure side refrigerant flow path 17a and exchanges heat with the low-pressure refrigerant passing through the low-pressure side refrigerant flow path 17b.

  On the other hand, in the second operation mode, the control device turns on the first and second on-off valves 24 and 25. That is, the first on-off valve 24 is opened, and the second on-off valve 25 is closed. Therefore, in the second operation mode, the high-pressure refrigerant that has flowed out of the receiver 16 flows into the temperature type expansion valve 18 via the bypass passage 23, so heat exchange is not performed in the internal heat exchanger 17.

  As a result, even in this embodiment, even if the first operation mode and the second operation mode are switched according to the change in the heat load condition of the cycle, the internal heat exchanger 17 can perform appropriate heat exchange. And the same effects as those of the first embodiment can be obtained.

(Fourth embodiment)
In the present embodiment, a bypass passage that bypasses the first high-pressure side refrigerant flow path 21a of the first heat exchange section 21 of the internal heat exchanger 20, as shown in the overall configuration diagram of FIG. 23 and an on-off valve 24 for opening and closing the bypass passage 23, and the connection relationship between the first and second low-pressure side refrigerant passages 21b and 22b of the internal heat exchanger 20 is changed.

  Specifically, the bypass passage 23 is a refrigerant passage that connects the liquid-phase refrigerant outlet of the receiver 16 and the first high-pressure side refrigerant flow path 21a and the second high-pressure side refrigerant flow path 22a. Therefore, the bypass passage 23 of the present embodiment bypasses a part of the high-pressure side refrigerant flow path 17a of the high internal heat exchanger 17.

  The on-off valve 24 has the same configuration as the first on-off valve 24 of the third embodiment. The outlet side of the evaporator 19 is connected to the refrigerant inlet 14a of the branching section 14 via the second low-pressure side refrigerant flow path 22b → the first low-pressure side refrigerant flow path 22a. Other configurations are the same as those of the second embodiment.

  Next, the operation of this embodiment will be described. In the first operation mode, the control device puts the on-off valve 24 in a non-energized state. That is, the on-off valve 24 is closed. Accordingly, in the first operation mode, the high-pressure refrigerant passes through the first and second high-pressure side refrigerant passages 21a and 22a, and exchanges heat with the low-pressure refrigerant passing through the first and second low-pressure side refrigerant passages 21b and 22b.

  On the other hand, in the second operation mode, the control device puts the on-off valve 24 in an energized state. That is, the on-off valve 24 is in an open state. Accordingly, in the second operation mode, a part of the high-pressure refrigerant that has flowed out of the receiver 16 flows into the second high-pressure side refrigerant flow path 22a via the bypass passage 23, so that the amount of heat exchange in the first heat exchange unit 21 Decrease.

  As a result, even in this embodiment, even if the first operation mode and the second operation mode are switched according to the change in the heat load condition of the cycle, the internal heat exchanger 20 can perform appropriate heat exchange. And the same effects as those of the second embodiment can be obtained.

(Fifth embodiment)
The present embodiment is different from the third embodiment in that the first and second on-off valves 24 and 25 are eliminated and the high-pressure side refrigerant flow path 17a of the internal heat exchanger 17 is removed as shown in the overall configuration diagram of FIG. In addition, an electric flow rate adjusting valve 26 for adjusting a flow rate ratio between the refrigerant flow rate flowing into the high-pressure side refrigerant flow path 17a side and the refrigerant flow rate flowing into the bypass passage 23 side is provided upstream of the bypass passage 23.

  The operation of the flow rate adjusting valve 26 is controlled by a control signal output from a control device (not shown). More specifically, the flow rate of the refrigerant that flows into the high-pressure side refrigerant flow path 17a in the first operation mode is controlled to be larger than the flow rate of the refrigerant that flows into the high-pressure side refrigerant flow path 17a in the second operation mode. The Other configurations are the same as those of the third embodiment.

  Therefore, when the refrigeration cycle apparatus 10 of the present embodiment is operated, the heat exchange amount in the first operation mode of the internal heat exchanger 17 is increased more than the heat exchange amount in the second operation mode. That is, in any operation mode, the heat exchange amount in the internal heat exchanger 17 can be appropriately adjusted, so that the cycle can be appropriately operated even if the heat load condition of the cycle changes.

(Sixth embodiment)
In each of the embodiments described above, only the temperature type expansion valve 18 is used as the pressure reducing means. However, in the present embodiment, as shown in the overall configuration diagram of FIG. To do. The ejector 30 is a decompression unit that decompresses the refrigerant, and is also a refrigerant circulation unit that circulates the refrigerant by suction of a refrigerant flow ejected at high speed.

  In the present embodiment, an intermediate pressure side branch portion 31 that branches the flow of the intermediate-pressure refrigerant decompressed and expanded by the temperature type expansion valve 18 is provided on the downstream side of the temperature type expansion valve 18. One of the branched refrigerants flows into the nozzle portion 30 a side of the ejector 30, and the other refrigerant flows into the refrigerant suction port 30 b side of the ejector 30 through the refrigerant branch passage 32.

  The ejector 30 squeezes the passage area of the intermediate pressure refrigerant flowing out of the temperature type expansion valve 18 small, and communicates with the nozzle portion 30a that decompresses and expands the refrigerant isentropically, and the refrigerant injection port of the nozzle portion 30a. It has a refrigerant suction port 30b that is arranged and sucks the refrigerant that has flowed out of the second evaporator 34 described later.

  Furthermore, a mixing unit 30c that mixes the high-speed jet refrigerant jetted from the nozzle unit 30a and the suction refrigerant from the refrigerant suction port 30b is provided in the refrigerant flow downstream portion of the nozzle unit 30a and the refrigerant suction port 30b. A diffuser portion 30d forming a pressure increasing portion is provided on the refrigerant flow downstream side of the mixing portion 30c.

  The diffuser portion 30d is formed in a shape that gradually increases the refrigerant passage area, and functions to increase the refrigerant pressure by decelerating the refrigerant flow, that is, to convert the velocity energy of the refrigerant into pressure energy. Further, the first evaporator 19 is connected to the outlet side of the diffuser portion 30 d of the ejector 30. The first evaporator 19 is an endothermic heat exchanger corresponding to the evaporator 19 of the first embodiment.

  On the other hand, the other refrigerant branched by the intermediate pressure side branch portion 31 flows into the refrigerant suction port 30 b side of the ejector 30 through the refrigerant branch passage 32. A fixed throttle 33 and a second evaporator 34 are disposed in the refrigerant branch passage 32. The fixed throttle 33 is a decompression unit that is disposed on the upstream side of the refrigerant flow of the second evaporator 34 and decompresses and expands the refrigerant flowing into the second evaporator 34. As the fixed throttle 33, specifically, a capillary tube or an orifice can be employed.

  The second evaporator 34 exchanges heat between the low-pressure refrigerant passing through the interior and the internal air circulated and blown from the electric blower 19a, thereby evaporating the low-pressure refrigerant and exerting an endothermic effect. It is a vessel. Further, the second evaporator 34 is disposed on the downstream side of the internal blower air flow (arrow 100) with respect to the first evaporator 19.

  Accordingly, the blown air blown by the electric blower 19a flows in the direction of the arrow 100, and is first cooled by the first evaporator 19 and then cooled by the second evaporator 34 and blown into the freezer that is the cooling target space. Is done. That is, in this embodiment, the same cooling target space is cooled by the first evaporator 19 and the second evaporator 34.

  Moreover, in this embodiment, the 1st evaporator 19 and the 2nd evaporator 34 are comprised with the heat exchanger of a fin and tube structure, and the heat exchange fin of the 1st evaporator 19 and the 2nd evaporator 34 is made common, The first evaporator 19 and the second evaporator 34 are configured as an integral structure by providing a tube configuration for circulating the refrigerant flowing out from the ejector 30 and a tube configuration for circulating the refrigerant flowing out from the fixed throttle 33 independently of each other. is doing.

  Of course, the first evaporator 19 and the second evaporator 34 may be constituted by two separate evaporators, and may be arranged in series in the air passage direction (the direction of arrow 100 in FIG. 1).

  Next, the operation of this embodiment in the above configuration will be described with reference to the Mollier diagram of FIG. In addition, the continuous line of FIG. 8 has shown the state of the refrigerant | coolant in 1st operation mode, and the broken line has shown the state of the refrigerant | coolant in 2nd operation mode.

First, in the first operation mode, as in the first embodiment, the high-pressure refrigerant (point A _{3 in} FIG. 8) discharged from the first compressor 11 is discharged from the radiator 15 → the receiver 16 → the internal heat exchanger 17. The enthalpy flows in order and becomes a liquid-phase refrigerant having an appropriate degree of supercooling, and is decompressed and expanded to an intermediate pressure by the temperature expansion valve 18 (A ₃ point → B ₃ point → C ₃ point in FIG. 8). D1 ₃ points).

The intermediate pressure refrigerant on the downstream side of the temperature type expansion valve 18 is branched at the intermediate pressure side branch portion 31, and one of the branched refrigerant flows into the nozzle portion 30 a of the ejector 30 and is decompressed and expanded in an isentropic manner. (D1 ₃ point → D2 ₃ point in FIG. 8). And the pressure energy of a refrigerant | coolant is converted into velocity energy at the time of this decompression | expansion expansion, and a refrigerant | coolant is injected from the refrigerant | coolant injection port of the nozzle part 30a.

Due to the refrigerant suction action of the injected refrigerant, the refrigerant after passing through the second evaporator 34 is sucked from the refrigerant suction port 30b. Further, the refrigerant injected from the nozzle portion 30a and the suction refrigerant sucked from the refrigerant suction port 30b are mixed in the mixing portion 30c and the pressure is increased in the diffuser portion 30d (D2 ₃ point → D3 _{3 in} FIG. 8). Point → D4 ₃ points).

The refrigerant that has flowed out of the diffuser section 30d flows into the first evaporator 19, absorbs heat from the internal air circulated by the electric blower 19a, evaporates, and cools the internal blown air. Then, the refrigerant that has flowed out of the first evaporator 19 passes through the low-pressure side refrigerant flow path 17b of the internal heat exchanger 17 and is sucked into the first compressor 11 again (D4 ₃ point → E _{3 in} FIG. 8). Point → F ₈ points).

The other refrigerant branched at the middle pressure side branch portion 31 flows is isenthalpic depressurize and expanded by the fixed throttle 33 to the second evaporator 34 (D1 ₃ points → D5 ₃ points in FIG. 8). Refrigerant flowing into the second evaporator 34, absorbs heat and evaporates from the internal air blown by the electric blower 19a, to cool the storage room blown air (D5 ₃ points → D6 ₃ points in FIG. 8). And the refrigerant | coolant which flowed out from the 2nd evaporator 34 is attracted | sucked from the refrigerant | coolant suction opening 30b (D63 ₃ point-> D3 ₃ point of FIG. 3).

  Since the first operation mode operates as described above, the degree of supercooling of the high-pressure refrigerant flowing into the temperature type expansion valve 18 and the nozzle portion 30a of the ejector 30 in the internal heat exchanger 17 as in the first embodiment. The enthalpy difference of the refrigerant between the refrigerant inlet and outlet in the first and second evaporators 19 and 34 can be increased. As a result, COP can be improved.

  Furthermore, the same air to be cooled (in the refrigerator) can be cooled by passing the air blown from the electric blower 19a in the order of the first evaporator 19 → the second evaporator 34. At that time, the refrigerant evaporating pressure (refrigerant evaporating temperature) of the first evaporator 19 can be made higher than the refrigerant evaporating pressure (refrigerant evaporating temperature) of the second evaporator 34 by the pressure increasing action of the diffuser portion 30d.

  Therefore, the temperature difference between the refrigerant evaporation temperature of the first evaporator 19 and the second evaporator 34 and the blown air can be secured, and the blown air can be efficiently cooled.

  Further, since the downstream side of the first evaporator 19 is connected to the suction side of the first compressor 11 and the refrigerant boosted by the diffuser portion 30d is sucked into the first compressor 11, the suction of the first compressor 11 is performed. The driving power of the first compressor 11 can be reduced by increasing the pressure. As a result, cycle efficiency (COP) can be further effectively improved.

Next, in the second operating mode, (A _4-point in FIG. 8) the high-pressure refrigerant discharged from the second compressor 12, similarly to the first operation mode, and flows into the radiator 15, the receiver 16 → internal heat The high-pressure side refrigerant flow path 17a of the exchanger 17 → the temperature type expansion valve 18 → the medium-pressure side branch portion 31 flows in this order. (A _4-point in FIG. 8 → C ₄ points → D1 ₄ points).

Then, the refrigerant flowing from the intermediate pressure side branch portion 31 to the nozzle portion 30 side of the ejector 30 is decompressed and expanded in an isentropic manner, exhibits a heat absorption action in the first evaporator 19, and the low pressure of the internal heat exchanger 17. is sucked into the second compressor 12 without passing through a side refrigerant passage 17b (D1 ₄ points in FIG. 8 → D2 ₄ points → D3 ₄ points → D4 ₄ points → F ₄ points).

Therefore, in the internal heat exchanger 17, heat exchange between the high-pressure refrigerant and the low-pressure refrigerant is not performed, and the high-pressure side refrigerant flow path 17a functions as a simple refrigerant passage. The refrigerant that has flowed from the intermediate pressure side branch portion 31 to the fixed throttle 33 side is decompressed and expanded in an enthalpy manner, exhibits a heat absorbing action in the second evaporator 34 as in the first operation mode, and the refrigerant in the ejector 30 It is sucked into the suction port 30b (D1 ₄ point → D5 ₄ point → D6 ₄ point → D3 ₄ point in FIG. 8).

  Since it operates as described above in the second operation mode, the degree of supercooling of the high-pressure refrigerant flowing into the temperature type expansion valve 18 and the nozzle portion 30a of the ejector 30 is unnecessarily increased as in the first embodiment. That can be avoided. Accordingly, the first and second evaporators 19 and 34 can reliably exhibit the refrigerating capacity. Furthermore, the COP improvement effect by the pressure | voltage rise effect | action of the diffuser part 30d of the ejector 30 can also be acquired similarly to the 1st operation mode.

  At this time, in the second operation mode of the present embodiment, since it is possible to avoid an unnecessary increase in the degree of supercooling of the high-pressure refrigerant flowing into the nozzle portion 30a of the ejector 30, recovery of the expansion loss energy of the ejector 30 can be avoided. Reduction of the amount (hereinafter referred to as “recovered energy amount”) can be effectively suppressed.

Explaining this in more detail, the amount of recovered energy in the second operation mode is represented by ΔH ₄ in FIG. On the other hand, when the high-pressure refrigerant flowing into the nozzle portion 30a of the ejector 30 is a liquid-phase refrigerant having a degree of supercooling more than necessary, the amount of recovered energy is ΔH as shown by the one-dot chain line in FIG. ₄ 'decreases to (C _4' of FIG. 8 points → D ₄ 'points).

  When the amount of recovered energy decreases, the amount of pressure increase in the diffuser portion 30d also decreases, and the COP improvement effect due to the pressure increasing action of the diffuser portion 30d described above also decreases.

  That is, as in the present embodiment, in the refrigeration cycle apparatus 10 that employs the ejector 30 as the decompression means, the diffuser portion 30d is prevented by preventing the supercooling degree of the refrigerant flowing into the ejector 30 from increasing unnecessarily. The COP improvement effect by the pressure | voltage rise effect | action of can be acquired effectively. Of course, even if the ejector 30 is added as the pressure reducing means to the overall configuration of the second to fifth embodiments, the COP improvement effect can be obtained effectively.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows.

  (1) In each of the above-described embodiments, an example of the refrigeration cycle apparatus 10 employing two compressors, the first and second compressors 11 and 12, has been described, but the number of compressors is two. It is not limited to.

  For example, even if a plurality of compressors are connected in parallel to the first and second first compressors 11 and 12 and the compressor to be operated is switched, the internal capacity is changed according to changes in the heat load conditions of the cycle. If the amount of heat exchange in the heat exchanger 17 is appropriately adjusted, the same effect as in the above-described embodiment can be obtained.

  (2) In each of the above-described embodiments, only the first compressor 11 is driven in the first operation mode, and only the second compressor 12 is driven in the second operation mode. It may be provided. For example, there may be an operation mode in which the first and second compressors 11 and 12 are driven simultaneously.

  (3) In the second and fourth embodiments described above, the example in which the internal heat exchanger is divided into two has been described, but the number of divisions of the internal heat exchanger is not limited to this. For example, the internal heat exchanger 20 is divided into a plurality of heat exchange units having the same heat exchange capability, and the number of heat exchange units to be used is changed so that an appropriate heat exchange amount is obtained in each operation mode. Alternatively, the number of heat exchange parts to be bypassed may be changed.

  (4) In the above-described embodiment, the evaporators 19 and 34 are used for cooling in the freezer. However, the use of the evaporators 19 and 34 is not limited to this. For example, it is not limited to vehicles, and may be used for indoor air conditioning as a stationary refrigeration cycle apparatus. In the sixth embodiment, the same cooling target space is cooled by the two evaporators 19 and 34, but different cooling target spaces may be cooled by the two evaporators 19 and 34.

  (5) In the second embodiment described above, the first and second on-off valves 24 and 25 are employed as the opening and closing means for opening and closing the bypass passage 23, but the opening and closing means is not limited to this. In the first operation mode, any open / close means that allows high-pressure refrigerant to flow into the high-pressure side refrigerant flow path 17a of the internal heat exchanger 17 and in the second operation mode to allow high-pressure refrigerant to flow into the bypass passage 23. Good. For example, a three-way valve may be provided at the most upstream part of the bypass passage 23.

  (6) In the above-described sixth embodiment, the refrigeration cycle apparatus in which the intermediate pressure side branching portion 31 is disposed on the upstream side of the ejector 30 has been described, but the configuration of the ejector refrigeration cycle to which the present invention can be applied is described here. It is not limited. For example, the receiver 16 is abolished, the refrigerant flowing out from the radiator 15 is directly flowed into the ejector 30, and the liquid-phase refrigerant is sucked into the evaporator 19 from the gas-liquid separator arranged on the downstream side of the ejector 30. It is good.

  (7) In the above-described embodiment, the radiator 15 is an outdoor heat exchanger that exchanges heat between the refrigerant and the outside air, and the evaporators 19 and 34 are applied as indoor heat exchangers for cooling the freezer compartment. On the contrary, the evaporators 19 and 34 are configured as outdoor heat exchangers that absorb heat from a heat source such as outside air, and the radiator 15 is configured as an indoor heat exchanger that heats a fluid to be heated such as air or water. The present invention may be applied to a heat pump cycle.

It is a whole lineblock diagram of the refrigerating cycle device of a 1st embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant of 1st Embodiment. It is a whole block diagram of the refrigerating-cycle apparatus of 2nd Embodiment. It is a whole block diagram of the refrigerating-cycle apparatus of 3rd Embodiment. It is a whole refrigeration cycle apparatus block diagram of 4th Embodiment. It is a whole block diagram of the refrigerating-cycle apparatus of 5th Embodiment. It is a whole block diagram of the refrigerating-cycle apparatus of 6th Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant of 6th Embodiment. It is a Mollier diagram for demonstrating the problem of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... 1st compressor, 12 ... 2nd compressor, 12a ... Electric motor, 14 ... Branch part,
15 ... radiator, 17, 20 ... internal heat exchanger,
17a ... high pressure side refrigerant flow path, 17b ... low pressure side refrigerant flow path,
21a ... 1st high pressure side refrigerant flow path, 21b ... 1st low pressure side refrigerant flow path,
22a ... second high pressure side refrigerant flow path, 22b ... second low pressure side refrigerant flow path,
18 ... temperature type expansion valve, 19 ... (first) evaporator, 23 ... bypass passage,
24 ... 1st on-off valve, 25 ... 2nd on-off valve, 26 ... Flow control valve,
30 ... Ejector, 30a ... Nozzle part, 34 ... Second evaporator.

Claims (7)

A first compressor (11) for compressing and discharging the refrigerant;
A second compressor (12) connected in parallel to the first compressor (11) for compressing and discharging the refrigerant;
A radiator (15) for radiating heat from the refrigerant discharged from the first compressor (11) and the refrigerant discharged from the second compressor (12);
Decompression means (18, 30) for decompressing and expanding the refrigerant downstream of the radiator (15);
A refrigeration cycle apparatus comprising an evaporator (19, 34) for evaporating the refrigerant decompressed and expanded by the decompression means (18, 30),
The first compressor (11) is an engine-driven compressor that obtains driving force from an engine,
The second compressor (12) is an electric compressor that obtains driving force from the electric motor (12a),
The maximum refrigerant discharge capacity of the second compressor (12) is smaller than the maximum refrigerant discharge capacity of the first compressor (11),
Furthermore, an internal heat exchanger (17, 20) for exchanging heat between the high-pressure refrigerant on the downstream side of the radiator (15) and the low-pressure refrigerant on the downstream side of the evaporator (19, 34),
The internal heat exchanger (17, 20) is in a second operation mode in which the heat exchange amount in the first operation mode for driving only the first compressor (11) drives only the second compressor (12). A refrigeration cycle apparatus that performs heat exchange so as to be greater than a heat exchange amount. The flow of the refrigerant flowing out of the evaporator (19, 34) is branched, and one branched low-pressure refrigerant is guided to the suction port side of the first compressor (11) and the other branched low-pressure refrigerant is A branching portion (14) for guiding the second compressor (12) to the suction port side,
At least a part of the low-pressure side refrigerant flow path (17b, 21b, 22b) of the internal heat exchanger (17, 20) flows out from the branch part (14) to the suction side of the first compressor (11). The refrigeration cycle apparatus according to claim 1, wherein only the refrigerated refrigerant flows. A first compressor (11) for compressing and discharging the refrigerant;
A second compressor (12) connected in parallel to the first compressor (11) for compressing and discharging the refrigerant;
A radiator (15) for radiating heat from the refrigerant discharged from the first compressor (11) and the refrigerant discharged from the second compressor (12);
Decompression means (18, 30) for decompressing and expanding the refrigerant downstream of the radiator (15);
A refrigeration cycle apparatus comprising an evaporator (19, 34) for evaporating the refrigerant decompressed and expanded by the decompression means (18, 30),
Furthermore, an internal heat exchanger (17, 20) for exchanging heat between the high-pressure refrigerant downstream of the radiator (15) and the low-pressure refrigerant downstream of the evaporator (19, 34) ;
The flow of the refrigerant flowing out from the evaporator (19, 34) is branched, and one branched low-pressure refrigerant is guided to the suction port side of the first compressor (11), and the other branched low-pressure refrigerant is And a branch portion (14) for guiding the second compressor (12) to the suction port side ,
At least a part of the low-pressure side refrigerant flow path (17b, 21b, 22b) of the internal heat exchanger (17, 20) flows out from the branch part (14) to the suction side of the first compressor (11). Only the refrigerated refrigerant circulates,
The internal heat exchanger (17, 20) is in a second operation mode in which the heat exchange amount in the first operation mode for driving only the first compressor (11) drives only the second compressor (12). A refrigeration cycle apparatus that performs heat exchange so that the amount of heat exchange is greater than the amount of heat exchange. A bypass passage (23) for bypassing at least a part of the high-pressure side refrigerant flow path (17a, 21a, 22a) of the internal heat exchanger (17, 20);
Opening and closing means (24, 25) for opening and closing the bypass passage (23),
The switching means (24, 25) is, in the first operation mode to close the bypass passage (23), in the second operation mode according to claim 1, characterized in that opening the bypass passage (23) Refrigeration cycle equipment. A bypass passage (23) for bypassing at least a part of the high-pressure side refrigerant flow path (17a, 21a, 22a) of the internal heat exchanger (17, 20);
A flow rate adjustment valve (26) for adjusting a flow rate ratio of the refrigerant flowing into the high-pressure side refrigerant flow path (17a, 21a, 22a) and the bypass passage (23) side;
The flow rate adjusting valve (26) controls the flow rate of the refrigerant flowing into the high-pressure side refrigerant flow path (17a, 21a, 22a) in the first operation mode, and the high-pressure side refrigerant flow path ( 17. The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus increases the refrigerant flow rate to flow into 17 a, 21 a, and 22 a). The first compressor (11) is an engine-driven compressor that obtains driving force from an engine,
The refrigeration cycle apparatus according to claim 3 , wherein the second compressor (12) is an electric compressor that obtains a driving force from an electric motor (12a). The decompression means sucks the refrigerant into the interior by a high-speed refrigerant flow injected from the nozzle part (30a) for decompressing and expanding the high-pressure refrigerant, and mixes the sucked refrigerant and the high-speed refrigerant flow to increase the pressure. The refrigeration cycle apparatus according to any one of claims 1 to 6 , wherein the refrigeration cycle apparatus is configured by an ejector (30).

Images