Refrigeration cycle device

Abstract

The present invention comprises: a compressor (11) that takes in, compresses, and discharges a refrigerant; a condenser (13) that radiates heat of the refrigerant discharged from the compressor (11); a decompression section part (14a, 14b) that decompresses the refrigerant from which heat was radiated by the condenser (13); an evaporator (18, 19) that evaporates the refrigerant which has been decompressed by the decompression section part (14a, 14b); a gas-liquid separating part (15) that performs liquid-gas separation of the refrigerant; a liquid storage part (16, 91) that receives flow of one portion of refrigerant separated by the gas-liquid separating part (15) and that stores the refrigerant in a liquid phase; and a bypass section part (17, 92) that causes the other portion of the refrigerant separated by the gas-liquid separating part (15) to bypass the liquid storage part (16, 91) and flow out to the intake port side of the compressor (11).

Description

Refrigeration cycle apparatus Cross Reference to Related Applications

[0001] The present application is based on Japanese Patent Application No. 2025-66061 filed on April 14, 2025, the entire content of which is incorporated herein by reference.

[0002] The present disclosure relates to a refrigeration cycle apparatus.

[0003] Conventionally, Patent Document 1 and the like describe a refrigeration cycle apparatus that heats a heating target using heat generated by compression work of a compressor. In this conventional technique, the refrigerant discharged from the compressor circulates in the order of the water-refrigerant heat exchanger as a condenser, an expansion valve, an evaporator, and the suction port of the compressor, and at the same time, circulates to the suction port of the compressor by bypassing the water-refrigerant heat exchanger, the expansion valve, and the evaporator.

[0004] The refrigerant discharged from the compressor circulates to the suction port of the compressor by bypassing the water-refrigerant heat exchanger, the expansion valve, and the evaporator, so that the suction pressure of the compressor increases and the discharge flow rate of the compressor increases.

[0005] In this conventional technique, excess liquid-phase refrigerant in the cycle is stored by a receiver or an accumulator.

[0006] Japanese Patent No. 7298580 Publication

[0007] In the above conventional technique, since the discharge flow rate of the compressor increases, the flow rate of the refrigerant flowing into the receiver or the accumulator (hereinafter referred to as a liquid storage section) also increases. Therefore, the refrigerant flowing into the liquid storage section agitates the liquid-phase refrigerant stored inside the liquid storage section, and the excess liquid-phase refrigerant flows out of the liquid storage section.

[0008] In view of the above points, the present disclosure aims to suppress the agitation of the liquid-phase refrigerant stored inside the liquid storage section by the refrigerant flowing into the liquid storage section.

[0009] A refrigeration cycle apparatus according to one aspect of the present disclosure includes a compressor, a radiator, a pressure reducing section, an evaporator, a gas-liquid separation section, a liquid storage section, and a bypass section.

[0010] The compressor draws in the refrigerant, compresses it, and discharges it. The radiator dissipates heat from the refrigerant discharged from the compressor. The pressure reduction section reduces the pressure of the refrigerant that has been cooled by the radiator. The evaporator evaporates the refrigerant that has been reduced in pressure in the pressure reduction section. The gas-liquid separation section separates the refrigerant into gas and liquid phases. The liquid storage section receives one phase of the refrigerant separated in the gas-liquid separation section and stores the liquid phase refrigerant. The bypass section allows the other phase of the refrigerant separated in the gas-liquid separation section to flow out towards the compressor's intake side, bypassing the liquid storage section.

[0011] According to this design, one of the refrigerants separated in the gas-liquid separation section flows into the liquid reservoir, while the other refrigerant separated in the gas-liquid separation section bypasses the liquid reservoir, thus reducing the flow rate of refrigerant into the liquid reservoir. Therefore, it is possible to suppress the stirring up of the liquid phase refrigerant stored inside the liquid reservoir by the refrigerant flowing into the reservoir.

[0012] The above-mentioned and other purposes, features and advantages of this disclosure will become clearer from the following detailed description with reference to the attached drawings. This is an overall configuration diagram of the refrigeration cycle device of the first embodiment. This is a cross-sectional view showing the accumulator, etc., of the refrigeration cycle device of the first embodiment. This is a block diagram showing the electrical control unit of the refrigeration cycle device of the first embodiment. This is a Mollier diagram showing the change in the state of the refrigerant when the refrigeration cycle device of the first embodiment is in hot gas heating mode. This is a flowchart showing part of the control processing performed by the control device of the first embodiment when it is in hot gas heating mode. This is a cross-sectional view showing the accumulator, etc., of the refrigeration cycle device of the second embodiment. This is an overall configuration diagram of the refrigeration cycle device of the third embodiment. This is an overall configuration diagram of the refrigeration cycle device of the fourth embodiment. This is an overall configuration diagram of the refrigeration cycle device of the fifth embodiment.

[0013] Several embodiments for implementing this disclosure are described below with reference to the drawings. In each embodiment, parts corresponding to matters described in a prior embodiment are denoted by the same reference numerals, and redundant descriptions may be omitted. If only a part of the configuration is described in each embodiment, other parts of the configuration can be applied to other embodiments described in advance. Not only are combinations of parts that are explicitly shown to be combinable in each embodiment possible, but embodiments can also be partially combined even if not explicitly shown, as long as there are no particular problems with the combination.

[0014] (First Embodiment) A first embodiment of the refrigeration cycle device 10 according to the present disclosure will be described with reference to Figures 1 to 4. The refrigeration cycle device 10 is applied to a vehicle air conditioning system installed in an electric vehicle. An electric vehicle is a vehicle that obtains driving force for driving from an electric motor. The vehicle air conditioning system of this embodiment is an air conditioning system that provides air conditioning to the vehicle interior, which is the space to be air-conditioned, and also has a heat-generating equipment temperature control function that adjusts the temperature of heat-generating equipment.

[0015] The refrigeration cycle device 10, shown in the overall configuration diagram of Figure 1, is a vehicle air conditioning system that cools or heats the air supplied to the vehicle interior and also regulates the temperature of the battery 70, which is a heat-generating device. The object to be heated in the refrigeration cycle device 10 is air. The refrigeration cycle device 10 can switch refrigerant circuits according to various operating modes in order to control the air conditioning in the vehicle interior and regulate the temperature of the battery 70.

[0016] The refrigeration cycle device 10 uses an HFO-based refrigerant (specifically, R1234yf) as the refrigerant. The refrigeration cycle device 10 constitutes a subcritical refrigeration cycle in which the refrigerant pressure on the high-pressure side does not exceed the critical pressure of the refrigerant. The refrigerant is mixed with refrigerant oil for lubricating the compressor 11 of the refrigeration cycle device 10. The refrigerant oil is PAG oil (polyalkylene glycol oil) which is compatible with the liquid-phase refrigerant. A portion of the refrigerant oil circulates in the refrigeration cycle device 10 together with the refrigerant.

[0017] The compressor 11 in the refrigeration cycle system 10 draws in refrigerant, compresses it, and discharges it. The compressor 11 is located in the drive unit compartment on the front side of the passenger compartment. The drive unit compartment forms a space in which at least some of the equipment used for generating and adjusting the driving force for vehicle operation (e.g., a motor generator) is located.

[0018] The compressor 11 is an electric compressor that rotates a fixed-capacity compression mechanism with a fixed discharge capacity using an electric motor. The rotational speed (i.e., refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output from the control device 60.

[0019] The inlet side of the first three-way joint 12a is connected to the discharge port of the compressor 11. The first three-way joint 12a has three inlet and outlet ports that communicate with each other. The first three-way joint 12a can be a joint formed by joining multiple pipes, or a joint formed by providing multiple refrigerant passages in a metal block or resin block.

[0020] The refrigeration cycle device 10 is equipped with a second three-way joint 12b, a third three-way joint 12c, and a fourth three-way joint 12d. The basic configuration of the second three-way joint 12b, the third three-way joint 12c, and the fourth three-way joint 12d is the same as that of the first three-way joint 12a.

[0021] The first to fourth three-way joints 12a to 12d branch the flow of refrigerant when one of the three inlet / outlet ports is used as an inlet and the remaining two are used as outlets. The first to fourth three-way joints 12a to 12d merge the flow of refrigerant when two of the three inlet / outlet ports are used as inlets and the remaining one is used as an outlet. The first three-way joint 12a branches the flow of refrigerant discharged from the compressor 11.

[0022] One outlet of the first three-way joint 12a is connected to the refrigerant inlet side of the water refrigerant heat exchanger 13. The other outlet of the first three-way joint 12a is connected to the inlet side of the hot gas passage 21a.

[0023] The water refrigerant heat exchanger 13 is a heat dissipation unit that exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and the cooling water circulating in the first cooling water circuit 30, thereby releasing the heat contained in the high-pressure refrigerant into the cooling water.

[0024] The inlet side of the second three-way joint 12b is connected to the refrigerant outlet of the water refrigerant heat exchanger 13. The inlet side of the first expansion valve 14a is connected to one of the outlets of the second three-way joint 12b. The inlet side of the second expansion valve 14b is connected to one of the outlets of the second three-way joint 12b.

[0025] The first expansion valve 14a is a first pressure reducing unit that reduces the pressure of one of the refrigerants branched off by the second three-way joint 12b. The first expansion valve 14a is a refrigerant flow rate adjustment unit that adjusts the flow rate (i.e., mass flow rate) of the refrigerant flowing into the first evaporator 18.

[0026] The first expansion valve 14a is an electrically operated variable throttling mechanism having a valve body that changes the throttling opening and an electric actuator (specifically, a stepping motor) that displaces the valve body. The operation of the first expansion valve 14a is controlled by control pulses output from the control device 60.

[0027] The first expansion valve 14a has a fully open function that, when fully open, functions as a simple refrigerant passage with almost no refrigerant pressure reduction or flow rate adjustment effect. The first expansion valve 14a also has a fully closed function that, when fully closed, blocks the refrigerant passage.

[0028] The refrigeration cycle device 10 is equipped with a second expansion valve 14b and a hot gas flow control valve 14c. The basic configuration of the second expansion valve 14b and the hot gas flow control valve 14c is the same as that of the first expansion valve 14a.

[0029] The first expansion valve 14a, the second expansion valve 14b, and the hot gas flow rate control valve 14c are refrigerant circuit switching units that switch the refrigerant circuit by exhibiting a fully closing function. The first expansion valve 14a, the second expansion valve 14b, and the hot gas flow rate control valve 14c may also be formed by combining a variable throttle mechanism that does not have a fully closing function with an on / off valve. In this case, the on / off valve becomes the refrigerant circuit switching unit.

[0030] The outlet of the first expansion valve 14a is connected to the refrigerant inlet side of the first evaporator 18. The first evaporator 18 is a first evaporation unit that evaporates the low-pressure refrigerant that has been reduced in pressure by the first expansion valve 14a. The first evaporator 18 is a heat exchanger for cooling and dehumidifying the air that is blown into the vehicle interior. The air blown into the vehicle interior may be cooled and dehumidified directly by the first evaporator 18, or it may be cooled by the first evaporator 18 via cooling water.

[0031] The outlet of the second expansion valve 14b is connected to the inlet side of the refrigerant passage of the second evaporator 19 via a third three-way joint 12c. The second expansion valve 14b is a pressure reducing unit that reduces the pressure of the refrigerant flowing into the second evaporator 19. Furthermore, the second expansion valve 14b is a refrigerant flow rate adjustment unit that adjusts the flow rate (i.e., mass flow rate) of the refrigerant flowing into the second evaporator 19.

[0032] The second evaporator 19 is a second evaporation unit that evaporates the low-pressure refrigerant that has been depressurized by the second expansion valve 14b. The second evaporator 19 is a heat exchanger that cools the low-temperature cooling water by exchanging heat between the low-pressure refrigerant, which has been depressurized by the second expansion valve 14b, and the low-temperature cooling water circulating in a low-temperature cooling water circuit (not shown).

[0033] The low-temperature coolant circuit includes a radiator (not shown) and other on-board equipment (not shown). The radiator is a heat exchanger that exchanges heat between the low-temperature coolant and the outside air. The on-board equipment is equipment that requires cooling and is cooled by the low-temperature coolant. The on-board equipment may also be a battery 70.

[0034] The refrigerant outlets of the first evaporator 18 and the second evaporator 19 are connected to the inlet side of the branch section 15 via the fourth three-way joint 12d.

[0035] The branching section 15 branches the flow of refrigerant discharged from the fourth three-way joint 12d to the accumulator 16 side and the accumulator bypass section 17 side. The branching section 15 is a gas-liquid separation section that separates the gas and liquid of the incoming refrigerant. Various gas-liquid separation methods can be adopted in the branching section 15. In this embodiment, the refrigerant flow path of the branching section 15 is designed to separate gas and liquid by utilizing the inertia and pressure loss of the refrigerant passing through the branching section 15.

[0036] The liquid-phase refrigerant separated at the branching section 15 (in other words, the refrigerant with a low degree of dryness) flows out from the first outlet of the branching section 15, and the gaseous-phase refrigerant separated at the branching section 15 (in other words, the refrigerant with a high degree of dryness) flows out from the second outlet of the branching section 15.

[0037] The first outlet of the branch section 15 is connected to the refrigerant inlet of the accumulator 16. The second outlet of the branch section 15 is connected to the refrigerant inlet of the accumulator bypass section 17.

[0038] The accumulator bypass section 17 forms a bypass flow path through which the highly dry refrigerant that has flowed out from the second outlet of the branch section 15 bypasses the accumulator 16.

[0039] A bypass valve 21 is located in the accumulator bypass section 17. The bypass valve 21 is a solenoid valve that opens and closes the bypass passage of the accumulator bypass section 17.

[0040] The accumulator 16 is a low-pressure gas-liquid separator and reservoir that further separates the gas-liquid of the less dry refrigerant that has flowed out from the first outlet of the branching section 15, and stores the excess liquid-phase refrigerant in the cycle. The first inlet of the confluence section 20 is connected to the gas-phase refrigerant outlet of the accumulator 16.

[0041] The confluence section 20 combines the flow of refrigerant discharged from the accumulator 16 with the flow of refrigerant discharged from the accumulator bypass section 17. The outlet of the confluence section 20 is connected to the suction port side of the compressor 11.

[0042] Figure 2 schematically shows an example of the arrangement of the accumulator 16, branch section 15, accumulator bypass section, merging section 20, and bypass valve 21.

[0043] The accumulator 16 has a container 161 that forms a space for separating the gaseous and liquid phases of the refrigerant and a space for storing the liquid phase of the refrigerant. The container 161 has an inlet 161a through which the refrigerant flows in and an outlet 161b through which the refrigerant flows out.

[0044] The branching section 15 has an inflow port 15a, a first outflow port 15b, and a second outflow port 15c. The first outflow port 15b of the branching section 15 is connected to the inflow port 161a of the container 161.

[0045] The accumulator bypass section 17 has a refrigerant inlet 17a and a refrigerant outlet 17b. The merging section 20 has a first inflow port 20a, a second inflow port 20b, and an outflow port 20c. The first inflow port 20a of the merging section 20 is connected to the outflow port 161b of the container 161.

[0046] A facing plate 162, an outer outflow pipe 163, and an inner outflow pipe 164 are disposed in the internal space of the container 161.

[0047] The facing plate 162 is a plate-shaped member disposed at the upper part of the container 161 so as to face the first outflow port 15b of the branching section 15. The refrigerant that has flowed into the interior of the container 161 from the refrigerant inlet of the container 161 collides with the facing plate 162 and then undergoes gas-liquid separation. The facing plate 162 is provided to prevent the refrigerant flowing into the interior of the container 161 from directly colliding with the liquid surface of the liquid-phase refrigerant stored in the interior of the container 161 and entraining the liquid-phase refrigerant.

[0048] The outer outflow pipe 163 and the inner outflow pipe 164 form a double pipe extending in the vertical direction inside the container 161. The upper end of the outer outflow pipe 163 opens above the liquid surface of the liquid-phase refrigerant in the container 161 and below the facing plate 162, and the lower end of the outer outflow pipe 163 is closed at the lower part of the container 161. The inner outflow pipe 164 is disposed inside the outer outflow pipe 163. The lower end of the inner outflow pipe 164 opens at the lower part of the outer outflow pipe 163, and the upper end of the inner outflow pipe 164 is connected to the first inflow port 20a of the merging section 20.

[0049] The second outflow port 15c of the branching section 15 is connected to the refrigerant inlet 17a of the accumulator bypass section 17, and the refrigerant outlet 17b of the accumulator bypass section 17 is connected to the second inflow port 20b of the merging section 20. The outflow port 20c of the merging section 20 is connected to the suction port side of the compressor 11.

[0050] The branch section 15, the accumulator bypass section 17, and the junction section 20 can be joints formed by joining multiple pipes, or joints formed by providing multiple refrigerant passages in a metal block or a resin block.

[0051] As shown in Figure 1, the outlet side of the hot gas passage 21a is connected to the third three-way joint 12c. The second evaporator 19 mixes the bypass refrigerant that has flowed out from the hot gas flow control valve 14c with the refrigerant that has flowed out from the second expansion valve 14b and discharges it to the suction side of the compressor 11.

[0052] The hot gas passage 21a is a refrigerant passage that guides the other refrigerant, which is branched off at the first three-way joint 12a, to the inlet side of the second evaporator 19. More specifically, the hot gas passage 21a is a refrigerant passage that bypasses the water refrigerant heat exchanger 13 and guides the other refrigerant, which is branched off at the first three-way joint 12a, to the suction port side of the compressor 11 via the second evaporator 19.

[0053] A hot gas flow rate adjustment valve 14c is located in the hot gas passage 21a. The hot gas flow rate adjustment valve 14c is a hot gas flow rate adjustment unit that reduces the pressure of the refrigerant flowing through the hot gas passage 21a and adjusts the flow rate (mass flow rate) of the refrigerant flowing through the hot gas passage 21a.

[0054] Next, the first cooling water circuit 30 will be described. The first cooling water circuit 30 is a first heat transfer medium circuit that circulates cooling water. In the first cooling water circuit 30, an aqueous solution of ethylene glycol is used as the cooling water. The first cooling water circuit 30 is equipped with a water-refrigerant heat exchanger 13, a first cooling water pump 31, and a heater core 32.

[0055] The first cooling water pump 31 is a water pump that pressurizes and sends cooling water to the cooling water inlet side of the water refrigerant heat exchanger 13. The first cooling water pump 31 is an electric pump whose rotational speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 60.

[0056] The cooling water outlet of the water-refrigerant heat exchanger 13 is connected to the cooling water inlet side of the heater core 32. The heater core 32 is a heating heat exchange unit that heats the air by exchanging heat between the cooling water heated in the water-refrigerant heat exchanger 13 and the air that has passed through the first evaporator 18. The air heated by the heater core 32 is blown into the vehicle interior.

[0057] The cooling water outlet of the heater core 32 is connected to the suction port side of the first cooling water pump 31. Therefore, in this embodiment, the water-refrigerant heat exchanger 13 and the heater core 32 constitute an air heating section that heats the air using the refrigerant discharged from the compressor 11 as a heat source.

[0058] Next, the second cooling water circuit 40 will be described. The second cooling water circuit 40 is a second heat transfer medium circuit that circulates cooling water. The cooling water in the second cooling water circuit 40 is the same type of fluid as the cooling water in the first cooling water circuit 30. The second cooling water circuit 40 is equipped with a second cooling water pump 41 and a battery heater 42.

[0059] The second cooling water pump 41 is a water pump that pressurizes and sends cooling water to the cooling water inlet side of the battery heater 42. The basic configuration of the second cooling water pump 41 is the same as that of the first cooling water pump 31. The suction side of the second cooling water pump 41 is connected to the cooling water outlet of the battery heater 42. The battery 70 is in heat conduction-conductive contact with the battery heater 42, and the battery 70 is heated by the cooling water flowing through the battery heater 42.

[0060] The battery 70 stores power supplied to multiple electric in-vehicle devices. The battery 70 is a battery pack formed by electrically connecting multiple battery cells in series or parallel. The battery cells are rechargeable secondary batteries (lithium-ion batteries in this embodiment). The battery 70 is constructed by stacking multiple battery cells in a substantially rectangular parallelepiped shape and housing them in a dedicated case.

[0061] The battery 70 is a heat-generating device that generates heat during operation (i.e., during charging and discharging). The secondary battery forming the battery 70 is prone to reduced output as chemical reactions do not proceed easily at low temperatures. For this reason, it is desirable that the temperature of the secondary battery be maintained within an appropriate temperature range (15°C or higher in this embodiment) that allows for full utilization of the secondary battery's charging and discharging capacity.

[0062] Therefore, in this embodiment, the battery 70 is brought into contact with the battery heater 42 in a way that allows heat to be conducted, so that the battery 70 can be heated by the cooling water flowing through the battery heater 42.

[0063] The first cooling water circuit 30 and the second cooling water circuit 40 are connected to each other by a first connecting flow path section 50 and a second connecting flow path section 51. The cooling water flow path formed by the first connecting flow path section 50 is connected to the cooling water outlet side of the water refrigerant heat exchanger 13 in the first cooling water circuit 30 via a three-way valve 52, and to the suction side of the second cooling water pump 41 in the second cooling water circuit 40 via an introduction-side three-way joint 53. The cooling water flow path formed by the second connecting flow path section 51 is connected to the outlet side of the battery heater 42 in the second cooling water circuit 40 via an outlet-side three-way joint 54, and to the suction side of the first cooling water pump 31 in the first cooling water circuit 30 via a return-side three-way joint 55.

[0064] The three-way valve 52 is a flow rate ratio adjustment unit that adjusts the ratio of the flow rate of the cooling water branched from the first cooling water circuit to the first connecting flow path section 50. The first connecting flow path section 50, the second connecting flow path section 51, and the three-way valve 52 are a flow rate adjustment unit that adjusts the flow rate of the cooling water in the battery heater 42.

[0065] When the three-way valve 52 sets the flow rate ratio of the cooling water branching from the first cooling water circuit 30 to the second cooling water circuit 40 to 0%, the cooling water circulates independently in the first cooling water circuit 30 and the second cooling water circuit 40. In this case, the cooling water flow rate in the battery heater 42 in the second cooling water circuit 40 is equal to or greater than the minimum flow rate. The minimum flow rate is a predetermined flow rate that is the minimum necessary to suppress uneven flow of cooling water to the battery heater 42 and temperature variations in the battery 70.

[0066] When the three-way valve 52 sets the flow rate ratio of the cooling water branching from the first cooling water circuit 30 to the second cooling water circuit 40 to be greater than 0%, the cooling water from the first cooling water circuit 30 flows into the second cooling water circuit 40 via the first connecting flow path section 50. The cooling water that flows from the first cooling water circuit 30 to the second cooling water circuit 40 via the first connecting flow path section 50 flows through the battery heater 42 and is branched at the outlet-side three-way joint 54. One portion of the cooling water branched at the outlet-side three-way joint 54 circulates in the second cooling water circuit 40. The other portion of the cooling water branched at the outlet-side three-way joint 54 returns to the first cooling water circuit 30 via the second connecting flow path section 51 and the return-side three-way joint 55. Therefore, the larger the flow rate ratio of the cooling water branching from the first cooling water circuit 30 to the second cooling water circuit 40 by the three-way valve 52, the greater the cooling water flow rate in the battery heater 42.

[0067] When the three-way valve 52 sets the flow rate ratio of the cooling water branching from the first cooling water circuit 30 to the second cooling water circuit 40 to 100%, no cooling water from the first cooling water circuit 30 flows into the heater core 32, and the entire flow rate of the cooling water from the first cooling water circuit 30 flows into the second cooling water circuit 40 via the first connecting flow path section 50.

[0068] Therefore, the flow rate adjustment unit, consisting of the first connecting flow path section 50, the second connecting flow path section 51, and the three-way valve 52, can adjust the flow rate of the cooling water in the battery heater 42 while maintaining the flow rate of the cooling water in the battery heater 42 at or above the minimum flow rate.

[0069] Next, the electrical control unit of this embodiment will be described based on the block diagram in Figure 3. The control device 60 has a well-known microcomputer including a CPU, ROM, and RAM, and peripheral circuits. The control device 60 performs various calculations and processes based on the control program stored in the ROM. Then, based on the calculation and processing results, the control device 60 controls the operation of various controlled devices 11, 14a, 14b, 14c, 21, 31, 41, 52, etc. connected to the output side.

[0070] The control device 60 is connected to the input side of an internal temperature sensor 61a, an external temperature sensor 61b, a solar radiation sensor 61c, a first refrigerant pressure sensor 62a, a second refrigerant pressure sensor 62b, an evaporator temperature sensor 63a, an air conditioning air temperature sensor 63b, a battery temperature sensor 64, an inlet coolant temperature sensor 65a, an outlet coolant temperature sensor 65b, and the like. The control device 60 receives detection signals from these control sensors.

[0071] The interior temperature sensor 61a is an interior temperature detection unit that detects the interior temperature Tr, which is the temperature inside the vehicle. The exterior temperature sensor 61b is an exterior temperature detection unit that detects the exterior temperature Tam, which is the temperature outside the vehicle. The solar radiation sensor 61c is a solar radiation detection unit that detects the amount of solar radiation As that is irradiated into the vehicle interior.

[0072] The first refrigerant pressure sensor 62a is a high-pressure detection unit that detects a first pressure P1, which is the pressure of the high-pressure refrigerant discharged from the compressor 11. The second refrigerant pressure sensor 62b is an outdoor unit pressure detection unit that detects a second pressure P2, which is the pressure of the low-pressure refrigerant drawn into the compressor 11.

[0073] The evaporator temperature sensor 63a is an evaporator temperature detection unit that detects the evaporator temperature Tefin, which is the refrigerant evaporation temperature in the first evaporator 18. For example, the evaporator temperature sensor 63a detects the temperature of the heat exchange fins of the first evaporator 18. The air conditioning air temperature sensor 63b is an air conditioning air temperature detection unit that detects the temperature TAV of the air blown into the vehicle cabin.

[0074] The battery temperature sensor 64 is a battery temperature detection unit that detects the battery temperature TB, which is the temperature of the battery 70. The battery temperature sensor 64 has multiple temperature detection units and detects the temperature at multiple locations on the battery 70. Therefore, the control device 60 can also detect the temperature distribution of each part of the battery 70. Furthermore, the average value of the detection values ​​from the multiple temperature sensors is used as the battery temperature TB.

[0075] The inlet coolant temperature sensor 65a is a first heat transfer medium temperature detection unit that detects the coolant temperature Twin, which is the temperature of the coolant flowing into the heater core 32. The outlet coolant temperature sensor 65b is a second heat transfer medium temperature detection unit that detects the outlet coolant temperature TWout, which is the temperature of the coolant flowing out of the heater core 32.

[0076] An operation panel 69 is connected to the input side of the control device 60. The operation panel 69 is located near the instrument panel at the front of the vehicle interior. Operation signals from various operation switches provided on the operation panel 69 are input to the control device 60.

[0077] The various operation switches provided on the control panel 69 include, specifically, an auto switch, an air conditioner switch, an airflow setting switch, and a temperature setting switch. The auto switch is an operation switch for setting or canceling the automatic control operation of the vehicle's air conditioning system. The air conditioner switch is an operation switch for requesting that the first evaporator 18 perform cooling and dehumidification of the air. The airflow setting switch is an operation switch for manually setting the airflow of the interior blower. The temperature setting switch is an operation switch for setting the interior temperature Tset.

[0078] The control device 60 in this embodiment is configured with an integrated control unit that controls various controlled devices connected to the output side. Therefore, the configuration (hardware and software) that controls the operation of each controlled device constitutes the control unit that controls the operation of each controlled device.

[0079] For example, the configuration of the control device 60 that controls the refrigerant discharge capacity of the compressor 11 (specifically, the rotational speed of the compressor 11) constitutes the discharge capacity control unit 60a. The configuration of the control device 60 that controls the operation of the first expansion valve 14a, the second expansion valve 14b, and the hot gas flow rate adjustment valve 14c constitutes the refrigerant flow rate control unit 60b. The configuration of the control device 60 that controls the operation of the bypass valve 21 constitutes the bypass shutoff control unit 60c. The configuration of the control device 60 that controls the operation of the three-way valve 52 constitutes the cooling water circuit control unit 60d.

[0080] Next, the operation of the vehicle air conditioning system of this embodiment in the above configuration will be described. In the vehicle air conditioning system of this embodiment, various operating modes are switched in order to control the air conditioning inside the vehicle and the temperature of the battery 70.

[0081] Examples of operating modes for air conditioning that a vehicle air conditioning system switches between include (a) heating mode and (b) dehumidifying heating mode. When operating in an air conditioning mode, the vehicle air conditioning system also operates in battery heating mode, which heats the battery 70 as needed.

[0082] Switching between various driving modes is performed by executing a control program that is pre-stored in the control device 60. The control program is executed when the vehicle system's start switch is turned on.

[0083] The control program switches the operating mode based on detection signals from various control sensors and operation signals from the control panel. More specifically, in this embodiment, the control program switches the operating mode mainly based on the outside temperature Tam detected by the outside temperature sensor 61b. An overview of the various operating modes is described below.

[0084] (a) Heating mode The heating mode is an operating mode in which heated air is blown into the vehicle interior in order to heat the vehicle interior. In heating mode, the control device 60 sets the second expansion valve 14b to a throttled state that exerts a refrigerant pressure reduction effect, and sets the hot gas flow rate adjustment valve 14c to a fully closed state.

[0085] Therefore, in the heating mode refrigeration cycle device 10, the refrigerant discharged from the compressor 11 circulates in the following order: water refrigerant heat exchanger 13, second expansion valve 14b, second evaporator 19, and the suction port of the compressor 11.

[0086] Therefore, in the heating mode refrigeration cycle device 10, a vapor compression type refrigeration cycle is configured in which the water-refrigerant heat exchanger 13 condenses the refrigerant and the second evaporator 19 evaporates the refrigerant. In the water-refrigerant heat exchanger 13, the refrigerant releases heat to the first cooling water circuit 30. As a result, the air in the heater core 32 of the first cooling water circuit 30 is heated, and the air heated by the heater core 32 is blown into the vehicle interior as warm air, thereby achieving heating of the vehicle interior.

[0087] In the heating mode of the refrigeration cycle device 10, the hot gas flow control valve 14c is in a fully closed state. Therefore, the refrigerant discharged from the compressor 11 is not branched to the hot gas passage 21a by the first three-way joint 12a.

[0088] In heating mode, the control device 60 controls the three-way valve 52 to branch the cooling water from the first cooling water circuit 30 to the second cooling water circuit 40, thereby allowing the cooling water heated in the water-refrigerant heat exchanger 13 to flow to the battery heater 42 and heat the battery 70.

[0089] (b) Dehumidifying heating mode The dehumidifying heating mode is an operating mode that blows dehumidified warm air into the vehicle interior in order to dehumidify and heat the vehicle interior.

[0090] In dehumidifying heating mode, the control device 60 sets the first expansion valve 14a and the second expansion valve 14b to a throttled state that exerts a refrigerant pressure reduction effect, and sets the hot gas flow rate adjustment valve 14c to a fully closed state.

[0091] Therefore, in the refrigeration cycle device 10 in dehumidifying heating mode, the refrigerant discharged from the compressor 11 circulates in the order of water refrigerant heat exchanger 13, first expansion valve 14a, first evaporator 18, and the suction port of the compressor 11, while simultaneously circulating in the order of water refrigerant heat exchanger 13, second expansion valve 14b, second evaporator 19, and the suction port of the compressor 11.

[0092] Therefore, in the refrigeration cycle device 10 in dehumidifying heating mode, a vapor compression type refrigeration cycle is configured in which the water-refrigerant heat exchanger 13 condenses the refrigerant, and the first evaporator 18 and second evaporator 19 evaporate the refrigerant. In the first evaporator 18, the refrigerant absorbs heat from the air, and in the second evaporator 19, the refrigerant absorbs heat from the low-temperature cooling water of a low-temperature cooling water circuit (not shown). In the water-refrigerant heat exchanger 13, the refrigerant condenses by releasing heat into the first cooling water circuit 30.

[0093] As a result, the air is cooled and dehumidified in the first evaporator 18, the dry air cooled and dehumidified in the first evaporator 18 is heated in the heater core 32 of the first cooling water circuit 30, and the dry, warm air heated in the heater core 32 is blown into the vehicle interior, thus achieving dehumidified heating of the vehicle interior.

[0094] In the refrigeration cycle device 10 in dehumidifying heating mode, the hot gas flow control valve 14c is in a fully closed state. Therefore, the refrigerant discharged from the compressor 11 is not branched to the hot gas passage 21a by the first three-way joint 12a.

[0095] In dehumidifying heating mode, the control device 60 controls the three-way valve 52 to branch the cooling water from the first cooling water circuit 30 to the second cooling water circuit 40, thereby allowing the cooling water heated in the water refrigerant heat exchanger 13 to flow to the battery heater 42 and heat the battery 70.

[0096] (c) Hot Gas Heating Mode The hot gas heating mode is an operating mode that provides heating to the vehicle interior when the outside temperature is extremely low. The hot gas heating mode is an operating mode that can be switched to when the outside temperature Tam is below -20°C, etc.

[0097] In hot gas heating mode, the control device 60 closes the first expansion valve 14a completely, restricts the second expansion valve 14b, and restricts the hot gas flow rate adjustment valve 14c.

[0098] Therefore, in the refrigeration cycle device 10 in hot gas heating mode, the refrigerant discharged from the compressor 11 circulates in the following order: water refrigerant heat exchanger 13, second expansion valve 14b, second evaporator 19, and the suction port of the compressor 11. At the same time, a portion of the refrigerant discharged from the compressor 11 circulates through the hot gas passage 21a in the following order: hot gas flow rate control valve 14c, second evaporator 19, and the suction port of the compressor 11.

[0099] The control device 60 appropriately controls the operation of other controlled equipment. For example, with respect to the compressor 11, it controls the refrigerant discharge capacity so that the cooling water temperature TWin detected by the inlet cooling water temperature sensor 65a approaches the target cooling water temperature. The control device 60 operates the first cooling water pump 31 and the second cooling water pump 41.

[0100] In the refrigeration cycle device 10 in hot gas heating mode, the state of the refrigerant changes as shown in the Mollier diagram in Figure 4. The refrigerant discharged from the compressor 11 (point a4 in Figure 4) is branched at the first three-way joint 12a. One of the refrigerants branched at the first three-way joint 12a flows into the water refrigerant heat exchanger 13 and releases heat to the cooling water (from point a4 to point b4 in Figure 4). As a result, the cooling water is heated.

[0101] The refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the second expansion valve 14b from the second three-way joint 12b and is depressurized (from point b4 to point c4 in Figure 4) because the first expansion valve 14a is in a fully closed state. The refrigerant flowing out of the second expansion valve 14b, which has a relatively low enthalpy, flows into the second evaporator 19.

[0102] Meanwhile, the other refrigerant branched off at the first three-way joint 12a flows into the hot gas passage 21a. The refrigerant flowing into the hot gas passage 21a is depressurized by the hot gas flow control valve 14c (from point a4 to point d4 in Figure 4). The refrigerant with relatively high enthalpy that has been depressurized by the hot gas flow control valve 14c flows into the second evaporator 19 as the bypass refrigerant (point d4 in Figure 4).

[0103] The bypass refrigerant and the reduced-pressure refrigerant mixed in the second evaporator 19 become an intake refrigerant with an enthalpy approximately equivalent to that of an ideal mixed refrigerant (from points c4 and d4 to e4 in Figure 4), and flow out of the second evaporator 19. The refrigerant flowing out of the second evaporator 19 is drawn into the compressor 11 and compressed again.

[0104] In the first cooling water circuit 30 of the hot gas heating mode, the cooling water is heated in the water refrigerant heat exchanger 13. As a result, the air is heated in the heater core 32 of the first cooling water circuit 30, and the air heated in the heater core 32 is blown into the vehicle interior as warm air, thus heating the vehicle interior.

[0105] In hot gas heating mode, the control device 60 controls the three-way valve 52 to branch the cooling water from the first cooling water circuit 30 to the second cooling water circuit 40, thereby allowing the cooling water heated in the water refrigerant heat exchanger 13 to flow to the battery heater 42 and heat the battery 70.

[0106] Figure 5 is a flowchart showing the control process that the control device 60 performs on the bypass valve 21 in hot gas heating mode. In step S100, it is determined whether the dryness of the refrigerant flowing into the accumulator bypass section 17 is high or low.

[0107] Whether the refrigerant flowing into the accumulator bypass section 17 is dry or not is determined, for example, based on the elapsed time since the compressor 11 was started. Specifically, if the elapsed time since the compressor 11 was started is shorter than a predetermined time, the refrigerant flowing into the accumulator bypass section 17 is deemed to be dry because the behavior of the refrigeration cycle is unstable, and if the elapsed time since the compressor 11 was started is longer than a predetermined time, the refrigeration cycle is deemed to be stable, and the refrigerant flowing into the accumulator bypass section 17 is deemed to be dry.

[0108] Whether the refrigerant flowing into the accumulator bypass section 17 is dry or not is determined, for example, based on whether the refrigerant flow is switched by the first expansion valve 14a, the second expansion valve 14b, and the bypass flow rate control valve 14. Specifically, if the refrigerant circuit is switched by at least one of the first expansion valve 14a, the second expansion valve 14b, and the bypass flow rate control valve 14, the behavior of the refrigeration cycle becomes unstable, and therefore the dryness of the refrigerant flowing into the accumulator bypass section 17 is determined to be low. On the other hand, if the refrigerant circuit is not switched by the first expansion valve 14a, the second expansion valve 14b, and the bypass flow rate control valve 14, the behavior of the refrigeration cycle is stable, and therefore the dryness of the refrigerant flowing into the accumulator bypass section 17 is determined to be high.

[0109] Whether the refrigerant flowing into the accumulator bypass section 17 is dry or not is determined, for example, based on whether or not the flow of the cooling water is switched by the three-way valve 52. Specifically, if the flow of the cooling water in the first cooling water circuit 30 and the second cooling water circuit 40 is switched by the three-way valve 52, the behavior of the refrigeration cycle becomes unstable, and therefore the dryness of the refrigerant flowing into the accumulator bypass section 17 is determined to be low. On the other hand, if the flow of the cooling water in the first cooling water circuit 30 and the second cooling water circuit 40 is not switched by the three-way valve 52, the behavior of the refrigeration cycle is stable, and therefore the dryness of the refrigerant flowing into the accumulator bypass section 17 is determined to be high.

[0110] Whether the refrigerant flowing into the accumulator bypass section 17 is dry or not is determined, for example, based on the change in the rotational speed of the compressor 11. Specifically, if the change in the rotational speed of the compressor 11 is greater than a predetermined amount, the behavior of the refrigeration cycle becomes unstable, and the dryness of the refrigerant flowing into the accumulator bypass section 17 is determined to be low. If the change in the rotational speed of the compressor 11 is less than a predetermined amount, the behavior of the refrigeration cycle is stable, and the dryness of the refrigerant flowing into the accumulator bypass section 17 is determined to be high.

[0111] If, in step S100, it is determined that the refrigerant flowing into the accumulator bypass section 17 is highly dry, the process proceeds to step S110, and the bypass valve 21 is opened. As a result, the gaseous refrigerant separated at the branching section 15 flows through the accumulator bypass section 17. That is, the gaseous refrigerant separated at the branching section 15 bypasses the accumulator 16 and reaches the confluence section 20. Meanwhile, the liquid refrigerant separated at the branching section 15 reaches the refrigerant inlet of the accumulator 16.

[0112] This reduces the flow rate of refrigerant into the container 161 of the accumulator 16, thereby preventing the liquid phase refrigerant stored in the container 161 of the accumulator 16 from being stirred up by the refrigerant flowing into the container 161 and flowing out from the refrigerant outlet of the accumulator 16.

[0113] If, in step S100, it is determined that the dryness of the refrigerant flowing into the accumulator bypass section 17 is low, the process proceeds to step S120, and the bypass valve 21 is closed. As a result, the gaseous refrigerant separated at the branching section 15 does not flow through the accumulator bypass section 17. In other words, the gaseous refrigerant separated at the branching section 15, along with the liquid refrigerant separated at the branching section 15, reaches the refrigerant inlet of the accumulator 16.

[0114] This prevents liquid-phase refrigerant from flowing into the accumulator bypass section 17 when the dryness of the refrigerant flowing into the accumulator bypass section 17 is low, thereby preventing the compressor 11 from drawing in liquid-phase refrigerant and causing a compressor failure.

[0115] As described above, in the vehicle air conditioning system of this embodiment, the refrigeration cycle device 10 switches the refrigerant circuit according to each operating mode, thereby enabling air conditioning in the vehicle interior and heating in the vehicle interior at extremely low outside temperatures.

[0116] In this embodiment, the system includes a branching section 15 for separating the refrigerant into gas and liquid phases, an accumulator 16 into which one of the refrigerants separated at the branching section 15 flows and stores the liquid phase refrigerant, and an accumulator bypass section 17 that bypasses the accumulator 16 and causes the other refrigerant separated at the branching section 15 to flow out to the intake side of the compressor 11.

[0117] According to this, one of the refrigerants separated at the branching section 15 flows into the accumulator 16, while the other refrigerant separated at the branching section 15 bypasses the accumulator 16, thus reducing the flow rate of refrigerant into the accumulator 16. Therefore, it is possible to suppress the stirring up of the liquid phase refrigerant stored inside the accumulator 16 by the refrigerant flowing into the accumulator 16.

[0118] In this embodiment, the accumulator 16 further separates the refrigerant flowing in from the branching section 15 into gas and liquid phases, and discharges the separated gas phase refrigerant. The confluence section 20 combines the refrigerant discharged from the accumulator 16 with the refrigerant discharged from the accumulator bypass section 17. This ensures that the refrigerant is reliably separated into gas and liquid phases by both the branching section 15 and the accumulator 16.

[0119] In this embodiment, the accumulator 16 separates the refrigerant into gas and liquid phases and has a container 161 for storing the liquid phase refrigerant. The branching section 15 and the accumulator bypass section 17 are located outside the container 161. The container 161 has an inlet 161a for allowing refrigerant to flow in from the branching section 15 and an outlet 161b for allowing gaseous or liquid phase refrigerant to flow out. With this configuration, the refrigerant can be reliably separated into gas and liquid phases by both the branching section 15 and the accumulator 16.

[0120] In this embodiment, the system includes a bypass valve 21 capable of blocking the flow of refrigerant in the accumulator bypass section 17, and a control device 60 that controls the bypass valve 21 based on the dryness of the refrigerant flowing into the accumulator bypass section 17. This makes it possible to suppress the flow rate of refrigerant bypassing the accumulator 16 from becoming excessive.

[0121] For example, the control device 60 controls the bypass valve 21 based on the elapsed time since the compressor 11 was started. This prevents the flow rate of refrigerant bypassing the reservoirs 16 and 91 from becoming excessive when the cycle operation is unstable.

[0122] For example, the control device 60 controls the bypass valve 21 based on whether or not the refrigerant flow is switched by at least one of the first expansion valve 14a, the second expansion valve 14b, and the hot gas flow rate control valve 14c. This prevents the flow rate of refrigerant bypassing the accumulator 16 from becoming excessive when the cycle operation is unstable.

[0123] For example, the control device 60 controls the bypass valve 21 based on whether or not the flow of cooling water is switched by the three-way valve 52. This prevents the flow rate of refrigerant bypassing the accumulator 16 from becoming excessive when the cycle operation is unstable.

[0124] For example, the control device 60 controls the bypass valve 21 based on the change in the rotational speed of the compressor 11. This prevents the flow rate of refrigerant bypassing the accumulator 16 from becoming excessive when the cycle operation is unstable.

[0125] In this embodiment, the control device 60 controls the bypass valve 21 to block the inflow of refrigerant into the accumulator bypass section 17 when the dryness of the refrigerant flowing into the accumulator bypass section 17 is lower than a predetermined level. This prevents the flow rate of refrigerant bypassing the accumulator 16 from becoming excessive in the accumulator cycle.

[0126] In this embodiment, the branching section 15, the accumulator 16, and the accumulator bypass section 17 are located downstream of the first evaporator 18, the second evaporator 19, and the mixing section 12c, and upstream of the compressor 11. This arrangement makes it possible to suppress the stirring up of the liquid phase refrigerant stored inside the accumulator 16 by the refrigerant flowing into the accumulator 16 during the hot gas heating mode of the accumulator cycle.

[0127] (Second Embodiment) As shown in Figure 6, in this embodiment, the branching section 15 has a centrifugal separation gas-liquid structure 15d. The centrifugal separation gas-liquid structure 15d separates the gas and liquid of the refrigerant by utilizing the centrifugal force in the flow of the refrigerant.

[0128] According to this, compared to the first embodiment which separates gas and liquid using the inertia and pressure loss of the refrigerant passing through the branch section 15, the gas-liquid separation performance can be improved, and the degree of design freedom for the branch section 15 can be increased, thus improving the ability to be mounted on a vehicle.

[0129] (Third Embodiment) In the first embodiment described above, it is possible to switch to a hot gas heating mode in which a portion of the heat generated by the compression work of the compressor is introduced into the second evaporator 19 by the refrigerant flowing through the hot gas passage 21a. In contrast, in the present embodiment shown in Figure 7, it is possible to switch to a thermal loop heating mode in which a portion of the heat generated by the compression work of the compressor is introduced into the second evaporator 19 by the cooling water flowing through the cooling water circuit 130.

[0130] The cooling water circuit 130 is a heat transfer medium circuit that circulates cooling water. In the cooling water circuit 130, an aqueous solution of ethylene glycol is used as the cooling water. The cooling water circuit 130 is equipped with a water-refrigerant heat exchanger 13, a cooling water pump 131, a second evaporator 19, and a heater core 32.

[0131] The cooling water pump 131 is a water pump that pressurizes and sends cooling water to the cooling water inlet side of the water refrigerant heat exchanger 13. The cooling water pump 131 is an electric pump whose rotational speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 60.

[0132] The cooling water outlet of the water refrigerant heat exchanger 13 is connected in parallel to the cooling water inlet side of the second evaporator 19 and the cooling water inlet side of the heater core 32. The suction side of the cooling water pump 131 is connected to the cooling water outlet of the second evaporator 19 and the cooling water outlet of the heater core 32.

[0133] A three-way valve 136 is located at the branching point between the cooling water inlet side of the second evaporator 19 and the cooling water inlet side of the heater core 32. A three-way joint 139 is located at the junction of the cooling water outlet side of the second evaporator 19 and the cooling water outlet side of the heater core 32.

[0134] The three-way valve 136 is a flow rate ratio adjustment unit that adjusts the flow rate ratio of the cooling water branched to the cooling water inlet side of the second evaporator 19. The three-way valve 136 is a heat transfer medium flow rate adjustment unit that adjusts the cooling water flow rate in the second evaporator 19.

[0135] In this embodiment, the thermal loop heating mode is an operating mode that can be switched to in place of the hot gas heating mode in the above embodiment.

[0136] The thermal loop heating mode is an operating mode that provides heating to the vehicle interior when the outside temperature is extremely low. This mode can be switched to when the outside temperature (Tam) is below -20°C, for example.

[0137] In thermal loop heating mode, the control device 60 closes the first expansion valve 14a completely and throttles the second expansion valve 14b. As a result, in the refrigeration cycle device 10 in thermal loop heating mode, the refrigerant discharged from the compressor 11 circulates in the following order: water refrigerant heat exchanger 13, second expansion valve 14b, second evaporator 19, and the intake port of the compressor 11.

[0138] The control device 60 appropriately controls the operation of other controlled equipment. For example, with respect to the compressor 11, it controls the refrigerant discharge capacity so that the cooling water temperature TWin detected by the inlet cooling water temperature sensor 65a approaches the target cooling water temperature. The control device 60 operates the cooling water pump 131. The control device 60 controls the three-way valve 136 so that the cooling water in the cooling water circuit 130 flows through the second evaporator 19. That is, it controls the three-way valve 136 so that the flow rate ratio of the cooling water branching to the cooling water inlet side of the second evaporator 19 is less than 100% at a predetermined opening degree (for example, 50%).

[0139] In the refrigeration cycle device 10 in thermal loop heating mode, the refrigerant discharged from the compressor 11 flows into the water-refrigerant heat exchanger 13 and dissipates heat into the cooling water in the cooling water circuit 130. As a result, the cooling water in the cooling water circuit 130 is heated.

[0140] The refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the second expansion valve 14b from the second three-way joint 12b and is depressurized because the first expansion valve 14a is in a fully closed state. The refrigerant flowing out of the second expansion valve 14b flows into the second evaporator 19 and absorbs heat from the cooling water in the cooling water circuit 130. The refrigerant flowing out of the second evaporator 19 is drawn into the compressor 11 and compressed again.

[0141] The cooling water heated in the water refrigerant heat exchanger 13 is split by a three-way valve 136 to the cooling water inlet side of the second evaporator 19 and the cooling water inlet side of the heater core 32. The cooling water split to the cooling water inlet side of the heater core 32 releases heat into the air through the heater core 32. As a result, the air heated by the heater core 32 is blown into the vehicle interior as warm air, thus providing heating to the vehicle interior.

[0142] In the thermal loop heating mode of this embodiment, the control device 60 executes the control process shown in the flowchart of Figure 4, i.e., the control process for the bypass valve 21, similar to the hot gas heating mode of the above embodiment. This makes it possible to achieve the same effects as in the above embodiment.

[0143] In this embodiment, the branching section 15, the accumulator 16, and the accumulator bypass section 17 are located downstream of the first evaporator 18 and the second evaporator 19 and upstream of the compressor 11. This arrangement makes it possible to suppress the stirring up of the liquid phase refrigerant stored inside the accumulator 16 by the refrigerant flowing into the accumulator 16 during the thermal loop heating mode of the accumulator cycle.

[0144] (Fourth Embodiment) In the first embodiment described above, it is possible to switch to a hot gas heating mode in which a portion of the heat generated by the compression work of the compressor is introduced into the second evaporator 19. However, in this embodiment shown in Figure 8, instead of the hot gas heating mode of the first embodiment described above, it is possible to switch to a coolant heating mode in which heat is absorbed from the heat supply equipment 81 via cooling water.

[0145] The low-temperature cooling water circuit 150 is a heat transfer medium circuit that circulates cooling water. In the low-temperature cooling water circuit 150, an aqueous solution of ethylene glycol is used as the cooling water. The cooling water circulating in the low-temperature cooling water circuit 150 is a low-temperature heat transfer medium. The cooling water circulating in the first cooling water circuit 30 is a high-temperature heat transfer medium.

[0146] The low-temperature cooling water circuit 150 includes a second evaporator 19, a low-temperature cooling water pump 151, and a heat supply device 81. The low-temperature cooling water pump 151 is a water pump that pressurizes and sends cooling water to the cooling water inlet side of the second evaporator 19. The low-temperature cooling water pump 151 is an electric pump whose rotational speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 60.

[0147] The cooling water outlet of the second evaporator 19 is connected to the cooling water inlet side of the heat supply device 81. The heat supply device 81 is a device that supplies heat to the cooling water of the low-temperature cooling water circuit 150, and is, for example, an electric heater or a powertrain device. The cooling water outlet of the heat supply device 81 is connected to the suction side of the low-temperature cooling water pump 151.

[0148] The coolant heating mode is an operating mode that increases the discharge flow rate of the compressor 11 by introducing heat supplied from the heat supply device 81 to the second evaporator 19 via cooling water.

[0149] In coolant heating mode, the control device 60 closes the first expansion valve 14a completely and restricts the second expansion valve 14b. As a result, in the refrigeration cycle device 10 in coolant heating mode, the refrigerant discharged from the compressor 11 circulates in the following order: water refrigerant heat exchanger 13, second expansion valve 14b, second evaporator 19, and the intake port of the compressor 11.

[0150] The control device 60 appropriately controls the operation of other controlled devices. For example, with respect to the compressor 11, it controls the refrigerant discharge capacity so that the battery temperature TB detected by the battery temperature sensor 64 approaches the target battery temperature TBO. The control device 60 operates the first cooling water pump 31, the second cooling water pump 41, and the low-temperature cooling water pump 151.

[0151] In the refrigeration cycle device 10 in coolant heating mode, the state of the refrigerant changes as follows: The refrigerant discharged from the compressor 11 flows into the water refrigerant heat exchanger 13, where it releases heat into the cooling water and condenses. As a result, the cooling water in the first cooling water circuit 30 is heated.

[0152] The refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the second expansion valve 14b from the second three-way joint 12b and is depressurized because the first expansion valve 14a is in a fully closed state. The refrigerant flowing out of the second expansion valve 14b flows into the second evaporator 19 and evaporates by absorbing heat from the heat supply equipment 81 via the cooling water of the low-temperature cooling water circuit 150. The refrigerant flowing out of the second evaporator 19 is drawn into the compressor 11 and compressed again.

[0153] In the first cooling water circuit 30 in coolant heating mode, the cooling water is heated in the water-refrigerant heat exchanger 13. A portion of the cooling water heated in the water-refrigerant heat exchanger 13 is branched to the first connecting flow path section 50 by a three-way valve 52. The cooling water branched to the first connecting flow path section 50 flows into the second cooling water circuit 40 via the introduction-side three-way joint 53. In the second cooling water circuit 40, the cooling water flows into the heater core 32 and releases heat into the air. As a result, the air heated by the heater core 32 is blown into the vehicle interior as warm air, thus heating the vehicle interior.

[0154] The cooling water flowing out from the battery heater 42 is branched at the outlet-side three-way connector 54. One branch of the cooling water branched at the outlet-side three-way connector 54 circulates through the second cooling water circuit 40. The other branch of the cooling water branched at the outlet-side three-way connector 54 returns to the first cooling water circuit 30 via the return-side three-way connector 55.

[0155] In coolant heating mode, the control device 60 executes the control process shown in the flowchart of Figure 4, i.e., the control process for the bypass valve 21, similar to the hot gas heating mode in the above embodiment. This makes it possible to achieve the same effects as in the above embodiment.

[0156] In this embodiment, the branching section 15, the accumulator 16, and the accumulator bypass section 17 are located downstream of the first evaporator 18 and the second evaporator 19 and upstream of the compressor 11. This arrangement makes it possible to suppress the stirring up of the liquid phase refrigerant stored inside the accumulator 16 by the refrigerant flowing into the accumulator 16 during the coolant heating mode of the accumulator cycle.

[0157] (Fifth Embodiment) The refrigeration cycle device 10 of the first embodiment described above is an accumulator cycle equipped with an accumulator 16, but as shown in Figure 9, the refrigeration cycle device 10 of this embodiment is a receiver cycle equipped with a receiver 91.

[0158] The receiver 91 is a high-pressure gas-liquid separator and reservoir that separates the gaseous and liquid phases of the refrigerant that has flowed out from the refrigerant outlet of the water-refrigerant heat exchanger 13 and stores the excess liquid phase refrigerant in the cycle.

[0159] In this embodiment, the inlet of the branching section 15 is connected to the refrigerant outlet of the water refrigerant heat exchanger 13, one outlet of the branching section 15 is connected to the refrigerant inlet side of the receiver 91, and the other outlet of the branching section 15 is connected to the refrigerant inlet of the receiver bypass section 92. The liquid phase refrigerant outlet of the receiver 91 is connected to the first inlet of the merging section 20.

[0160] The receiver bypass section 92 forms a bypass flow path through which refrigerant with a low degree of dryness that has flowed out from the second outlet of the branch section 15 bypasses the receiver 91. The refrigerant outlet of the receiver bypass section 92 is connected to the second inlet of the merging section 20. A bypass valve 21 is located in the receiver bypass section 92. The bypass valve 21 opens and closes the bypass flow path of the receiver bypass section 92.

[0161] In hot gas heating mode, the control device 60 opens the bypass valve 21 when it determines that the dryness of the refrigerant flowing into the receiver bypass section 92 is low. As a result, the gaseous refrigerant separated at the branching section 15 flows through the receiver bypass section 92. That is, the liquid refrigerant separated at the branching section 15 bypasses the receiver 91 and reaches the confluence section 20. On the other hand, the gaseous refrigerant separated at the branching section 15 reaches the refrigerant inlet of the receiver 91.

[0162] This reduces the flow rate of refrigerant into the container 161 of the receiver 91, thereby preventing the liquid phase refrigerant stored in the container 161 of the receiver 91 from being stirred up by the refrigerant flowing into the container 161 and flowing out from the refrigerant outlet of the receiver 91.

[0163] On the other hand, if the control device 60 determines that the refrigerant flowing into the receiver bypass section 92 is dry, it closes the bypass valve 21. As a result, the liquid phase refrigerant separated at the branching section 15 does not flow through the receiver bypass section 92. In other words, the liquid phase refrigerant separated at the branching section 15, along with the gaseous phase refrigerant separated at the branching section 15, reaches the refrigerant inlet of the receiver 91.

[0164] This prevents gaseous refrigerant from flowing into the receiver bypass section 92 when the dryness of the refrigerant flowing into the receiver bypass section 92 is high, thereby preventing gaseous refrigerant from flowing into the first expansion valve 14a and the second expansion valve 14b.

[0165] Therefore, in a receiver cycle equipped with a receiver 91, it is possible to suppress the stirring up of the liquid phase refrigerant stored inside the receiver 91 by the refrigerant flowing into the receiver 91.

[0166] In this embodiment, the control device 60 controls the bypass valve 21 to block the inflow of refrigerant into the receiver bypass section 92 when the dryness of the refrigerant flowing into the receiver bypass section 92 is higher than a predetermined level. This prevents the flow rate of refrigerant bypassing the receiver 91 from becoming excessive in the receiver cycle.

[0167] In this embodiment, the branching section 15, the receiver 91, and the receiver bypass section 92 are arranged downstream of the upstream branching section 12a and the water refrigerant heat exchanger 13, and upstream of the first expansion valve 14a and the second expansion valve 14b. This arrangement makes it possible to suppress the stirring up of the liquid phase refrigerant stored inside the receiver 91 by the refrigerant flowing into the receiver 91 during the hot gas heating mode of the receiver cycle.

[0168] In this embodiment, the refrigeration cycle device 10 of the first embodiment is used as a receiver cycle, but the refrigeration cycle device 10 of the third embodiment may also be used as a receiver cycle. Specifically, the branching section 15, the receiver 91, and the receiver bypass section 92 may be arranged in the refrigeration cycle device 10 of the third embodiment downstream of the water refrigerant heat exchanger 13 and upstream of the first expansion valve 14a and the second expansion valve 14b. This makes it possible to suppress the stirring up of the liquid phase refrigerant stored inside the receiver 91 by the refrigerant flowing into the receiver 91 during the thermal loop heating mode of the receiver cycle.

[0169] The refrigeration cycle device 10 of the fourth embodiment described above may be a receiver cycle. Specifically, the branching section 15, the receiver 91, and the receiver bypass section 92 may be arranged in the refrigeration cycle device 10 of the fourth embodiment downstream of the water refrigerant heat exchanger 13 and upstream of the first expansion valve 14a and the second expansion valve 14b. This makes it possible to suppress the stirring up of the liquid phase refrigerant stored inside the receiver 91 by the refrigerant flowing into the receiver 91 in the coolant heating mode of the receiver cycle.

[0170] This disclosure is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit of this disclosure, as follows.

[0171] In the embodiments described above, an example was given in which the refrigeration cycle device 10 according to this disclosure is applied to a vehicle air conditioning system mounted on an electric vehicle, but the invention is not limited thereto. For example, the refrigeration cycle device 10 may be applied to a stationary air conditioning system used in cold regions, etc. Furthermore, the refrigeration cycle device 10 may be applied to a so-called hybrid vehicle that obtains driving force for vehicle operation from both an internal combustion engine and an electric motor for driving.

[0172] Furthermore, while the refrigeration cycle device 10 described in this disclosure is used to generate heat for heating the vehicle interior and heating the battery 70, it is not limited to this. For example, the refrigeration cycle device 10 may generate heat to defrost the radiator.

[0173] The configuration of the refrigeration cycle device 10 is not limited to those disclosed in the embodiments described above. For example, in the first and fifth embodiments described above, the outlet side of the hot gas passage 21a is connected between the second expansion valve 14b and the second evaporator 19, but the outlet side of the hot gas passage 21a may be connected between the second evaporator 19 and the compressor 11.

[0174] In the above-described embodiment, an example was given in which R1234yf was used as the refrigerant for the refrigeration cycle device 10, but the invention is not limited to this. For example, R134a, R600a, R410A, R404A, R32, R407C, etc. may be used. Alternatively, a mixed refrigerant, which is a mixture of several of these refrigerants, may be used.

[0175] In the embodiments described above, an example in which the cooling water is an aqueous solution of ethylene glycol was explained, but the invention is not limited to this. For example, a solution containing dimethylpolysiloxane or nanofluids, an antifreeze, an aqueous liquid coolant containing alcohol, or a liquid medium containing oil may be used.

[0176] The control mode of the refrigeration cycle device 10 is not limited to that disclosed in the above-described embodiment. For example, when the hot gas heating mode is selected at startup, it is desirable to stop the first cooling water pump 31 until the pressure of the refrigerant discharged from the compressor 11 exceeds a predetermined standard high pressure. This allows the cooling water to be heated quickly, and immediate heating can be expected.

[0177] In the above embodiment, the battery 70 was heated as a way to adjust its temperature, but it is also possible to cool the battery 70 with cooling water cooled in the second evaporator 19.

[0178] In the above embodiment, a cooling mode for cooling the interior of a vehicle is not described as an example of an operating mode for air conditioning. However, in the operation of the dehumidifying heating mode described above, a cooling mode can be achieved by suppressing the amount of heat generated by the heater core 32 and lowering the temperature of the air blown into the vehicle interior to a temperature lower than the temperature inside the vehicle.

[0179] The means disclosed in each of the above embodiments may be combined as appropriate to the extent that they are feasible.

[0180] The features of the refrigeration cycle apparatus disclosed herein are as follows: (Item 1) A refrigeration cycle apparatus comprising: a compressor (11) that inhales, compresses, and discharges a refrigerant; a heat sink (13) that dissipates heat from the refrigerant discharged from the compressor; a pressure reduction section (14a, 14b) that reduces the pressure of the refrigerant that has been heated by the heat sink; an evaporator (18, 19) that evaporates the refrigerant that has been reduced in pressure by the pressure reduction section; a gas-liquid separation section (15) that separates the refrigerant into gas-liquid form; a liquid storage section (16, 91) into which one of the refrigerants separated by the gas-liquid separation section flows and stores the liquid phase of the refrigerant; and a bypass section (17, 92) that causes the other refrigerant separated by the gas-liquid separation section to flow out to the intake side of the compressor, bypassing the liquid storage section. (Item 2) The refrigeration cycle apparatus according to Item 1, wherein the liquid storage section further separates the refrigerant flowing in from the gas-liquid separation section into gas-liquid and gas-liquid phases, discharges the separated gas-phase or liquid-phase refrigerant, and further comprises a confluence section (20) for combining the refrigerant discharged from the liquid storage section and the refrigerant discharged from the bypass section. (Item 3) The refrigeration cycle apparatus according to Item 1 or 2, wherein the liquid storage section separates the refrigerant into gas-liquid and gas-liquid phases and has a container (161) for storing the liquid-phase refrigerant, the gas-liquid separation section and the bypass section are located outside the container, and the container has an inlet (161a) for letting the refrigerant flow in from the gas-liquid separation section and an outlet (161b) for discharging the gas-phase or liquid-phase refrigerant. (Item 4) A refrigeration cycle apparatus according to any one of items 1 to 3, comprising: a bypass valve (21) capable of blocking the flow of the refrigerant in the bypass section; and a control unit (60) that controls the bypass valve based on the dryness of the refrigerant flowing into the bypass section. (Item 5) A refrigeration cycle apparatus according to item 4, wherein the control unit controls the bypass valve based on the elapsed time since the compressor was started. (Item 6) A refrigeration cycle apparatus according to item 4, comprising: a refrigerant circuit switching unit (14a, 14b, 14c) for switching the flow of the refrigerant; wherein the control unit controls the bypass valve based on whether or not the flow of the refrigerant is switched by the refrigerant circuit switching unit.(Item 7) The refrigeration cycle apparatus according to Item 4, comprising: a heat transfer medium circuit (30, 130) through which a heat transfer medium circulates; and a heat transfer medium circuit switching unit (50, 136) that switches the flow of the heat transfer medium in the heat transfer medium circuit, wherein at least one of the radiator and the evaporator exchanges heat between the refrigerant and the heat transfer medium; and the control unit controls the bypass valve based on whether or not the flow of the heat transfer medium is switched by the heat transfer medium circuit switching unit. (Item 8) The refrigeration cycle apparatus according to Item 4, wherein the control unit controls the bypass valve based on the amount of change in the rotational speed of the compressor. (Item 9) The refrigeration cycle apparatus according to any one of Items 4 to 8, wherein the gas-liquid separation unit, the liquid storage unit and the bypass unit are arranged downstream of the evaporator and upstream of the compressor; and the control unit controls the bypass valve to block the inflow of the refrigerant into the bypass unit when the dryness of the refrigerant flowing into the bypass unit is lower than a predetermined value. (Item 10) The refrigeration cycle apparatus according to any one of items 4 to 8, wherein the gas-liquid separation unit, the liquid storage unit, and the bypass unit are arranged downstream of the heat exchanger and upstream of the pressure reduction unit, and the control unit controls the bypass valve to block the inflow of the refrigerant into the bypass unit when the dryness of the refrigerant flowing into the bypass unit is higher than a predetermined value. (Item 11) The refrigeration cycle apparatus according to any one of items 1 to 8, comprising: an upstream branching section (12a) that branches the flow of the refrigerant discharged from the compressor to the radiator side and the other side; a hot gas passage (21a) that guides the refrigerant branched to the other side at the upstream branching section to the suction port side of the compressor; a hot gas flow rate adjustment section (14c) that adjusts the flow rate of the refrigerant flowing through the hot gas passage; and a mixing section (12c) that mixes the refrigerant discharged from the hot gas flow rate adjustment section and the refrigerant discharged from the pressure reduction section and discharges them to the suction port side of the compressor, wherein the gas-liquid separation section, the liquid storage section and the bypass section are located downstream of the evaporator and the mixing section and upstream of the compressor.(Item 12) The refrigeration cycle apparatus according to any one of items 1 to 8, comprising: an upstream branching section (12a) that branches the flow of the refrigerant discharged from the compressor to the radiator side and the other side; a hot gas passage (21a) that guides the refrigerant branched to the other side at the upstream branching section to the suction port side of the compressor; a hot gas flow rate adjustment section (14c) that adjusts the flow rate of the refrigerant flowing through the hot gas passage; and a mixing section (12c) that mixes the refrigerant discharged from the hot gas flow rate adjustment section and the refrigerant discharged from the pressure reduction section and discharges it to the suction port side of the compressor, wherein the gas-liquid separation section, the liquid storage section and the bypass section are located downstream of the upstream branching section and the radiator and upstream of the pressure reduction section. (Item 13) A refrigeration cycle apparatus according to any one of items 1 to 8, comprising a heat transfer medium circuit (130) for circulating a heat transfer medium to the radiator and the evaporator, and a heat transfer medium flow rate adjustment unit (136) for adjusting the flow rate of the heat transfer medium in the evaporator, wherein the gas-liquid separation unit, the liquid storage unit, and the bypass unit are located downstream of the evaporator and upstream of the compressor. (Item 14) A refrigeration cycle apparatus according to any one of items 1 to 8, comprising a heat transfer medium circuit (130) for circulating a heat transfer medium to the radiator and the evaporator, and a heat transfer medium flow rate adjustment unit (136) for adjusting the flow rate of the heat transfer medium in the evaporator, wherein the gas-liquid separation unit, the liquid storage unit, and the bypass unit are located downstream of the radiator and upstream of the pressure reduction unit. (Item 15) A refrigeration cycle apparatus according to any one of items 1 to 8, comprising: a heat transfer circuit (30) through which a heat transfer medium circulates; a heat supply unit (81) arranged in the heat transfer circuit and supplying heat to the heat transfer medium using a heat source different from the outside air; the evaporator causes the refrigerant to exchange heat with the heat transfer medium; and the gas-liquid separation unit, the liquid storage unit, and the bypass unit are arranged downstream of the evaporator and upstream of the compressor.(Item 16) A refrigeration cycle device according to any one of items 1 to 8, comprising: a heat transfer circuit (30) through which a heat transfer medium circulates; a heat supply unit (81) arranged in the heat transfer circuit and supplying heat to the heat transfer medium using a heat source different from the outside air; the evaporator causes the refrigerant to exchange heat with the heat transfer medium; and the gas-liquid separation unit, the liquid storage unit, and the bypass unit are arranged downstream of the radiator and upstream of the pressure reduction unit.

[0181] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.

Claims

1. A refrigeration cycle device comprising: a compressor (11) that inhales, compresses, and discharges a refrigerant; a heat sink (13) that dissipates heat from the refrigerant discharged from the compressor; a pressure reducing section (14a, 14b) that reduces the pressure of the refrigerant that has been heated by the heat sink; an evaporator (18, 19) that evaporates the refrigerant that has been reduced in pressure by the pressure reducing section; a gas-liquid separation section (15) that separates the refrigerant into gas-liquid form; a liquid storage section (16, 91) into which one of the refrigerants separated in the gas-liquid separation section flows and stores the liquid phase of the refrigerant; and a bypass section (17, 92) that causes the other refrigerant separated in the gas-liquid separation section to flow out to the intake side of the compressor, bypassing the liquid storage section.

2. The refrigeration cycle apparatus according to claim 1, wherein the liquid storage section further separates the refrigerant flowing in from the gas-liquid separation section into gas and liquid phases, discharges the separated gas phase or liquid phase of the refrigerant, and further comprises a confluence section (20) that combines the refrigerant discharged from the liquid storage section and the refrigerant discharged from the bypass section.

3. The refrigeration cycle apparatus according to claim 1, wherein the liquid storage section has a container (161) for separating the refrigerant into gas and liquid phases and for storing the liquid phase of the refrigerant, the gas-liquid separation section and the bypass section are located outside the container, and the container has an inlet (161a) for allowing the refrigerant to flow in from the gas-liquid separation section and an outlet (161b) for allowing the gaseous or liquid phase of the refrigerant to flow out.

4. The refrigeration cycle apparatus according to claim 1, comprising: a bypass valve (21) capable of blocking the flow of the refrigerant in the bypass section; and a control unit (60) that controls the bypass valve based on the dryness of the refrigerant flowing into the bypass section.

5. The refrigeration cycle apparatus according to claim 4, wherein the control unit controls the bypass valve based on the elapsed time since the compressor was started.

6. The refrigeration cycle apparatus according to claim 4, comprising a refrigerant circuit switching unit (14a, 14b, 14c) for switching the flow of the refrigerant, wherein the control unit controls the bypass valve based on whether or not the flow of the refrigerant is switched by the refrigerant circuit switching unit.

7. The refrigeration cycle apparatus according to claim 4, comprising: a heat transfer medium circuit (30, 130) through which a heat transfer medium circulates; and a heat transfer medium circuit switching unit (50, 136) for switching the flow of the heat transfer medium in the heat transfer medium circuit, wherein at least one of the radiator and the evaporator exchanges heat between the refrigerant and the heat transfer medium; and the control unit controls the bypass valve based on whether or not the flow of the heat transfer medium is switched by the heat transfer medium circuit switching unit.

8. The refrigeration cycle apparatus according to claim 4, wherein the control unit controls the bypass valve based on the amount of change in the rotational speed of the compressor.

9. The refrigeration cycle apparatus according to any one of claims 4 to 8, wherein the gas-liquid separation unit, the liquid storage unit, and the bypass unit are arranged downstream of the evaporator and upstream of the compressor, and the control unit controls the bypass valve to block the inflow of the refrigerant into the bypass unit when the dryness of the refrigerant flowing into the bypass unit is lower than a predetermined level.

10. The refrigeration cycle apparatus according to any one of claims 4 to 8, wherein the gas-liquid separation unit, the liquid storage unit, and the bypass unit are arranged downstream of the heat exchanger and upstream of the pressure reduction unit, and the control unit controls the bypass valve to block the inflow of the refrigerant into the bypass unit when the dryness of the refrigerant flowing into the bypass unit is higher than a predetermined value.

11. The refrigeration cycle apparatus according to claim 1, comprising: an upstream branching section (12a) that branches the flow of the refrigerant discharged from the compressor to the radiator side and the other side; a hot gas passage (21a) that guides the refrigerant branched to the other side at the upstream branching section to the suction port side of the compressor; a hot gas flow rate adjustment section (14c) that adjusts the flow rate of the refrigerant flowing through the hot gas passage; and a mixing section (12c) that mixes the refrigerant discharged from the hot gas flow rate adjustment section and the refrigerant discharged from the pressure reduction section and discharges them to the suction port side of the compressor, wherein the gas-liquid separation section, the liquid storage section and the bypass section are arranged downstream of the evaporator and the mixing section and upstream of the compressor.

12. The refrigeration cycle apparatus according to claim 1, comprising: an upstream branching section (12a) that branches the flow of the refrigerant discharged from the compressor to the radiator side and to the other side; a hot gas passage (21a) that guides the refrigerant branched to the other side at the upstream branching section to the suction port side of the compressor; a hot gas flow rate adjustment section (14c) that adjusts the flow rate of the refrigerant flowing through the hot gas passage; and a mixing section (12c) that mixes the refrigerant discharged from the hot gas flow rate adjustment section with the refrigerant discharged from the pressure reduction section and discharges it to the suction port side of the compressor, wherein the gas-liquid separation section, the liquid storage section and the bypass section are arranged downstream of the upstream branching section and the radiator and upstream of the pressure reduction section.

13. The refrigeration cycle apparatus according to claim 1, comprising: a heat transfer medium circuit (130) for circulating a heat transfer medium to the heat exchanger and the evaporator; and a heat transfer medium flow rate adjustment unit (136) for adjusting the flow rate of the heat transfer medium in the evaporator, wherein the gas-liquid separation unit, the liquid storage unit, and the bypass unit are located downstream of the evaporator and upstream of the compressor.

14. The refrigeration cycle apparatus according to claim 1, comprising: a heat transfer medium circuit (130) for circulating a heat transfer medium to the radiator and the evaporator; and a heat transfer medium flow rate adjustment unit (136) for adjusting the flow rate of the heat transfer medium in the evaporator, wherein the gas-liquid separation unit, the liquid storage unit, and the bypass unit are located downstream of the radiator and upstream of the pressure reduction unit.

15. The refrigeration cycle apparatus according to claim 1, comprising: a heat transfer medium circuit (30) through which a heat transfer medium circulates; a heat supply unit (81) arranged in the heat transfer medium circuit and supplying heat to the heat transfer medium using a heat source different from the outside air, wherein the evaporator causes the refrigerant to exchange heat with the heat transfer medium, and the gas-liquid separation unit, the liquid storage unit, and the bypass unit are arranged downstream of the evaporator and upstream of the compressor.

16. The refrigeration cycle apparatus according to claim 1, comprising: a heat transfer circuit (30) through which a heat transfer medium circulates; a heat supply unit (81) arranged in the heat transfer circuit and supplying heat to the heat transfer medium using a heat source different from the outside air; wherein the evaporator causes the refrigerant to exchange heat with the heat transfer medium; and the gas-liquid separation unit, the liquid storage unit, and the bypass unit are arranged downstream of the radiator and upstream of the pressure reduction unit.

Images