Refrigeration cycle apparatus

Abstract

A refrigeration cycle apparatus (10) comprises: a compressor (11); a first heating unit (12) that uses a refrigerant discharged from the compressor to heat blowing air to be blown to a space to be air-conditioned; and a second heating unit (14) that heats the blowing air by using the refrigerant that has passed through the first heating unit. The refrigeration cycle apparatus comprises: a bypass unit (13) that causes the refrigerant that has passed through the first heating unit to flow in a manner bypassing the second heating unit; and a refrigerant amount adjustment unit (FR) that adjusts the flow rate ratio of the refrigerant passing through the second heating unit and the refrigerant passing through the bypass unit. The refrigeration cycle apparatus further comprises: decompression units (16a, 16b) that reduce the pressure of the refrigerant that has passed through the second heating unit; and evaporation units (17, 18) that exchange heat with a fluid to be cooled and thereby evaporate the refrigerant that has been subjected to a pressure reduction by the decompression units. If heating of the blowing air by the second heating unit is unnecessary, the refrigerant amount adjustment unit adjusts the flow rate ratio so that at least some of the refrigerant that has passed through the first heating unit passes through the bypass section.

Description

Refrigeration Cycle Equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-084283, filed on May 23, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a refrigeration cycle device applied to an air conditioner.

[0003] Conventionally, a refrigeration cycle apparatus has been known that includes a first heating section that uses refrigerant discharged from a compressor as a heat source to heat the air to be blown into the vehicle cabin, and a second heating section that uses refrigerant that has passed through the first heating section as a heat source to heat the air to be blown (see, for example, Patent Document 1). The refrigeration cycle apparatus described in Patent Document 1 has both the second heating section and the first heating section functioning as heating sections that heat the air to be blown. The refrigeration cycle apparatus of Patent Document 1 also includes an interior condenser that constitutes the second heating section, and an air mix door that adjusts the ratio of the volume of the air flowing through the interior condenser to the volume of the air flowing bypassing the interior condenser. During cooling of the vehicle cabin, the air mix door is controlled to prevent the air from flowing into the interior condenser.

[0004] Japanese Patent Application Laid-Open No. 2019-34716

[0005] The refrigeration cycle apparatus of Patent Document 1 is configured so that the entire amount of high-temperature refrigerant flowing through the cycle always passes through the indoor condenser located in the ventilation path of the blown air. With this configuration, for example, when cooling a target space, the temperature of the air around the indoor condenser in the ventilation path and the components constituting the ventilation path are increased by the high-temperature refrigerant flowing through the indoor condenser. This is undesirable because it reduces the cooling performance of the target space. Thus, the refrigeration cycle apparatus described in Patent Document 1 does not particularly consider thermal damage caused by placing a heating unit in the ventilation path of the blown air to the target space, leaving room for improvement. The present disclosure aims to provide a refrigeration cycle apparatus that can suppress thermal damage caused by a heating unit located in the ventilation path of the blown air to the target space.

[0006] According to one aspect of the present disclosure, a refrigeration cycle device is applied to an air conditioning device, and includes: a compressor that compresses and discharges a refrigerant; a first heating section that heats blown air to be blown to a space to be air-conditioned using the refrigerant discharged from the compressor as a heat source; a second heating section that heats the blown air using the refrigerant after passing through the first heating section as a heat source; a bypass section that causes the refrigerant after passing through the first heating section to bypass the second heating section; a refrigerant amount adjustment section that adjusts the flow rate ratio of the refrigerant passing through the second heating section and the refrigerant passing through the bypass section; a decompression section that decompresses the refrigerant after passing through the second heating section; and an evaporation section that evaporates the refrigerant after being decompressed by the decompression section by heat exchange with a fluid to be cooled, wherein the refrigerant amount adjustment section adjusts the flow rate ratio so that the refrigerant after passing through the first heating section passes through the second heating section when heating of the blown air by the second heating section is required; When heating of the blown air by the second heating section is not required, the flow rate is adjusted so that at least a portion of the refrigerant after passing through the first heating section passes through the bypass section.

[0007] According to this, when heating of the blown air by the second heating unit is required, the refrigerant after passing through the first heating unit flows to the second heating unit, so that the blown air can be heated by both the first heating unit and the second heating unit. In addition, when heating of the blown air by the second heating unit is not required, the refrigerant after passing through the first heating unit flows bypassing the second heating unit, so that heat damage caused by the second heating unit can be suppressed.

[0008] 1 is a schematic configuration diagram of a vehicle air conditioner including a refrigeration cycle device according to a first embodiment.

[0023] FIG. 1 is an explanatory diagram illustrating a flow of a first heat medium in a heater core and a flow of a refrigerant in an interior condenser.

[0024] FIG. 2 is a block diagram illustrating an air conditioning control unit of the vehicle air conditioner according to the first embodiment.

[0025] FIG. 3 is a flowchart illustrating an example of the flow of a circuit control process executed by the air conditioning control unit of the refrigeration cycle device according to the first embodiment in a cooling mode.

[0026] FIG. 4 is an explanatory diagram illustrating a flow of a refrigerant in a first cooling mode.

[0027] FIG. 5 is an explanatory diagram illustrating a flow of a refrigerant in a second cooling mode.

[0028] FIG. 6 is an explanatory diagram illustrating the behavior of the refrigeration cycle device in the second cooling mode.

[0029] FIG. 7 is an explanatory diagram illustrating a flow of a refrigerant in a dehumidifying heating mode.

[0030] FIG. 8 is an explanatory diagram illustrating a flow of a refrigerant in a heating mode.

[0031] FIG. 9 is an explanatory diagram illustrating a flow of a refrigerant in a device cooling mode.

[0032] FIG. 10 is an explanatory diagram illustrating a flow of a refrigerant in a cooling & device cooling mode.

[0033] FIG. 11 is an explanatory diagram illustrating a refrigerant flow in a first dehumidifying heating & device cooling mode.

[0034] FIG. 12 is an explanatory diagram illustrating a flow of a refrigerant in a second dehumidifying heating & device cooling mode. Fig. 10 is a schematic configuration diagram of a refrigeration cycle device that is a modified example of a second embodiment. Fig. 11 is a flowchart showing an example of the flow of a circuit control process executed by a control unit of a refrigeration cycle device according to a third embodiment in a cooling mode. Fig. 12 is a flowchart showing an example of the flow of a circuit control process executed by a control unit of a refrigeration cycle device according to a fourth embodiment in a cooling mode. Fig. 13 is a schematic diagram showing the internal configuration of an air conditioning unit according to a fifth embodiment. Fig. 14 is a schematic diagram showing the internal configuration of an air conditioning unit according to a sixth embodiment.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same as or equivalent to those described in the preceding embodiments will be given the same reference numerals, and their description may be omitted. Furthermore, in the embodiments, when only some of the components are described, the components described in the preceding embodiments can be applied to the remaining components. The following embodiments can be partially combined with each other, even if not specifically stated, as long as there is no particular problem with the combination.

[0010] First Embodiment This embodiment will be described with reference to Figures 1 to 13. In this embodiment, an example will be described in which a refrigeration cycle device 10 according to the present disclosure is applied to a vehicle air conditioner 1 mounted on an electric vehicle that obtains driving power for running the vehicle from an electric motor. The refrigeration cycle device 10 mainly functions to adjust the temperature of the air blown into the vehicle cabin, which is the space to be air-conditioned in the vehicle air conditioner 1.

[0011] The vehicle air conditioner 1 performs cooling, dehumidifying heating, and heating within the vehicle cabin by adjusting the temperature of the blown air using the refrigeration cycle device 10. The vehicle air conditioner 1 of this embodiment has operating modes such as a first cooling mode, a second cooling mode, a dehumidifying heating mode, a heating mode, an equipment cooling mode, a cooling & equipment cooling mode, a first dehumidifying heating & equipment cooling mode, and a second dehumidifying heating & equipment cooling mode. The vehicle air conditioner 1 switches between various operating modes to maintain the vehicle cabin and the battery at appropriate temperatures.

[0012] The refrigeration cycle apparatus 10 employs, for example, an HFC refrigerant as a refrigerant. The refrigeration cycle apparatus 10 of this embodiment configures a subcritical refrigeration cycle in which the pressure of the high-pressure refrigerant discharged from the compressor 11 does not exceed the critical pressure of the refrigerant. Refrigerant oil is mixed into the refrigerant to lubricate the compressor 11. A portion of the refrigerant oil circulates within the cycle together with the refrigerant. Note that a refrigerant other than an HFC refrigerant may be employed.

[0013] As shown in Fig. 1, the refrigeration cycle apparatus 10 is configured as a vapor compression refrigeration cycle in which evaporated refrigerant is compressed by a compressor 11. The compressor 11 in the refrigeration cycle apparatus 10 draws in, compresses, and discharges the refrigerant. The compressor 11 is disposed, for example, inside the hood of the vehicle. The compressor 11 is an electric compressor whose refrigerant discharge capacity is controlled by a control signal output from an air conditioning control unit 60 (described later).

[0014] A water-refrigerant heat exchanger 12 is connected to the refrigerant discharge side of the compressor 11. The water-refrigerant heat exchanger 12 is a heat exchanger that exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and the first heat medium circulating through the first heat medium circuit 20, thereby heating the first heat medium.

[0015] The water-refrigerant heat exchanger 12 includes a first heat exchange section 121 through which the refrigerant flows and a second heat exchange section 122 through which the first heat medium flows. The first heat exchange section 121 is a subcooling condenser having a condenser section 121a, a receiver 121b, and a supercooling section 121c. The condenser section 121a condenses the refrigerant by heat exchange with the first heat medium flowing through the second heat exchange section 122. The receiver 121b separates the refrigerant that has passed through the condenser section 121a into gas and liquid and stores the excess liquid refrigerant. The supercooling section 121c further cools the liquid refrigerant stored in the receiver 121b by heat exchange with the first heat medium flowing through the second heat exchange section 122.

[0016] The second heat exchanger 122 is connected to the first heat medium circuit 20. The first heat medium circuit 20 is a water circuit that circulates a first heat medium. The first heat medium may be, for example, a solution containing ethylene glycol or antifreeze. The first heat medium circuit 20 includes the second heat exchanger 122, a first heat medium pump 21, a heater core 22, a first radiator 23, and a first flow control valve 24. The first heat medium pump 21 is a pump that pumps the first heat medium to the inlet side of the second heat exchanger 122 in the first heat medium circuit 20. The first heat medium pump 21 is an electric pump whose water pumping capacity is controlled by a control voltage output from the air conditioning control unit 60. The heater core 22 is disposed in a casing 51 of the indoor air conditioning unit 50 (described later). The heater core 22 is a heat exchanger that exchanges heat between the first heat medium heated in the water-refrigerant heat exchanger 12 and the blown air that has passed through the interior condenser 14 or the interior evaporator 17 (described later), thereby heating the blown air. The first radiator 23 is disposed on the front side of the vehicle hood. The first radiator 23 may be formed integrally with the water-refrigerant heat exchanger 12 or the like. The first radiator 23 is a heat exchanger that exchanges heat between the first heat medium heated in the water-refrigerant heat exchanger 12 and outside air blown by an outside air fan (not shown), thereby radiating heat from the first heat medium to the outside air.

[0017] The heater core 22 and the first radiator 23 are connected in parallel with respect to the flow of the first heat medium in the first heat medium circuit 20. The first flow rate adjustment valve 24 is a flow rate ratio adjustment unit that adjusts the flow rate ratio between the flow rate of the first heat medium flowing into the heater core 22 and the flow rate of the first heat medium flowing into the first radiator 23. The operation of the first flow rate adjustment valve 24 is controlled in response to a control signal output from the air conditioning control unit 60. When the first flow rate adjustment valve 24 adjusts the flow rate ratio, the flow rate of the first heat medium flowing into the heater core 22 changes. This adjusts the amount of heat released from the first heat medium in the heater core 22 to the blown air, i.e., the amount of heat of the blown air. In this embodiment, the first heat medium pump 21, the water-refrigerant heat exchanger 12, the heater core 22, the first flow rate adjustment valve 24, and the like arranged in the first heat medium circuit 20 constitute a “first heating unit” that heats the blown air using the refrigerant discharged from the compressor 11 as a heat source. In addition, the heater core 22 constitutes a "first heating heat exchanger" in the "first heating section" that dissipates heat from the refrigerant discharged from the compressor 11 to the blown air.

[0018] The refrigerant outlet side of the water-refrigerant heat exchanger 12 is connected to the refrigerant inlet side of the interior condenser 14. The interior condenser 14, together with the heater core 22, is disposed within the casing 51 of the interior air conditioning unit 50. The interior condenser 14 is disposed upstream of the heater core 22 in the flow of blown air. The interior condenser 14 is a heat exchanger that heats the blown air by exchanging heat between the high-pressure refrigerant that has passed through the water-refrigerant heat exchanger 12 and the blown air that has passed through an interior evaporator 17 (described later). In this embodiment, the interior condenser 14 constitutes a "second heating section" that heats the blown air using the refrigerant flowing out from the first heating section as a heat source. The interior condenser 14 also constitutes a "second heating heat exchanger" that transfers heat from the refrigerant that has passed through the water-refrigerant heat exchanger 12, which constitutes part of the "first heating section," to the blown air.

[0019] The interior condenser 14 and the heater core 22 are disposed opposite each other in the ventilation passage within the casing 51. The interior condenser 14 of this embodiment is disposed such that substantially the entire air outlet surface of the interior condenser 14 and substantially the entire air inlet surface of the heater core 22 face each other in the flow direction of the blown air. As shown in FIG. 2 , the interior condenser 14 has a refrigerant flow path configured such that the direction of the refrigerant flowing through the portion of the interior condenser 14 facing the heater core 22 is opposite the direction of the first heat medium flowing through the portion of the heater core 22 facing the interior condenser 14. While FIG. 2 illustrates an example in which the refrigerant flow in the interior condenser 14 is downward and the first heat medium flow in the heater core 22 is upward, this is not limiting. For example, the refrigerants may be disposed opposite to the direction shown in FIG. 2 . In this embodiment, the first heat medium flowing through the heater core 22 constitutes a “first fluid,” and the refrigerant flowing through the interior condenser 14 constitutes a “second fluid.”

[0020] A bypass section 13 is connected to the refrigerant outlet side of the water-refrigerant heat exchanger 12, allowing the refrigerant after passing through the water-refrigerant heat exchanger 12 to bypass the interior condenser 14. The bypass section 13 is arranged outside the casing 51 so as not to come into thermal contact with the air blown into the vehicle cabin. The upstream side of the bypass section 13 in the refrigerant flow direction is connected to a first branch section 13a provided on the refrigerant outlet side of the water-refrigerant heat exchanger 12, and the downstream side of the refrigerant flow direction is connected to a first junction section 13b provided on the refrigerant outlet side of the interior condenser 14.

[0021] The first branch portion 13a is provided with a refrigerant amount adjustment portion FR that adjusts the flow rate ratio of the refrigerant passing through the interior condenser 14 that constitutes the second heating portion and the refrigerant passing through the bypass portion 13. The refrigerant amount adjustment portion FR is configured with a flow path switching valve that selectively switches between a flow path that allows the refrigerant to flow to the interior condenser 14 and a flow path that allows the refrigerant to flow to the bypass portion 13. In this embodiment, the refrigerant amount adjustment portion FR is provided in the first branch portion 13a, but may also be provided in the first junction portion 13b.

[0022] The operation of refrigerant amount adjustment unit FR is controlled in response to a control signal output from air conditioning control unit 60. When heating of the blown air by interior condenser 14 constituting the second heating unit is required, refrigerant amount adjustment unit FR is controlled so that the refrigerant after passing through water-refrigerant heat exchanger 12 passes through interior condenser 14. When heating of the blown air by interior condenser 14 is not required, refrigerant amount adjustment unit FR is controlled so that at least a portion of the refrigerant after passing through water-refrigerant heat exchanger 12 passes through bypass unit 13.

[0023] The bypass section 13 is provided with a subcooler SC. The subcooler SC is arranged outside the casing 51 so as not to come into thermal contact with the blown air being blown into the vehicle cabin. The subcooler SC is, for example, a heat exchanger that exchanges heat between the refrigerant passing through the bypass section 13 and outside air, and radiates heat from the first heat medium to the outside air. In this embodiment, the subcooler SC constitutes a "heat radiator" that radiates heat from the refrigerant flowing through the bypass section 13 to a fluid other than the blown air.

[0024] The refrigerant inlet side of the second branch section 15a is connected to the downstream side of the first junction 13b. The second branch section 15a branches the refrigerant flow that flows out from the first junction 13b. The second branch section 15a has one refrigerant inlet and two refrigerant outlets. One refrigerant outlet of the second branch section 15a is connected to the refrigerant inlet side of the cooling expansion valve 16a, and the other refrigerant outlet is connected to the refrigerant inlet side of the heat absorption expansion valve 16b.

[0025] The cooling expansion valve 16a is a pressure reducing unit that reduces the pressure of the refrigerant at least in the cooling mode and the dehumidifying / heating mode, and also functions to adjust the flow rate of the refrigerant flowing into the indoor evaporator 17. The cooling expansion valve 16a is an electric variable throttle mechanism that includes a valve element configured to change the throttle opening and an electric actuator that changes the opening of the valve element. The operation of the cooling expansion valve 16a is controlled by a control signal output from the air conditioning control unit 60. The cooling expansion valve 16a has a full-closing function that closes the refrigerant passage. The refrigerant outlet side of the cooling expansion valve 16a is connected to the refrigerant inlet side of the indoor evaporator 17.

[0026] The interior evaporator 17 is disposed within the casing 51 of the interior air conditioning unit 50. Specifically, the interior evaporator 17 is disposed upstream of the interior condenser 14 and the heater core 22 in the flow of the blown air. The interior evaporator 17 is an air conditioning evaporation unit that, at least in the cooling mode and the dehumidifying / heating mode, exchanges heat between the low-pressure refrigerant decompressed by the cooling expansion valve 16a and the blown air to evaporate the low-pressure refrigerant and cool the blown air. The interior evaporator 17 is a cooling heat exchanger that cools the blown air, which is the fluid to be cooled, using the latent heat of vaporization of the refrigerant after passing through the cooling expansion valve 16a. The refrigerant outlet side of the interior evaporator 17 is connected to the inlet side of the evaporation pressure control valve 19.

[0027] The evaporation pressure control valve 19 is a pressure adjustment unit that maintains the refrigerant evaporation pressure in the indoor evaporator 17 at or above a predetermined reference pressure. The evaporation pressure control valve 19 is configured with a mechanical variable throttle mechanism that increases its valve opening as the refrigerant pressure at the refrigerant outlet side of the indoor evaporator 17 increases. In this embodiment, the evaporation pressure control valve 19 maintains the refrigerant evaporation temperature in the indoor evaporator 17 at or above a reference temperature (e.g., 1°C) that can prevent frost from forming on the indoor evaporator 17. A second junction 15b is connected to the refrigerant outlet side of the evaporation pressure control valve 19. The second junction 15b merges the refrigerant flow from the evaporation pressure control valve 19 with the refrigerant flow from the chiller 18. The second junction 15b has a three-way joint structure and includes two refrigerant inlets and one refrigerant outlet.

[0028] The heat-absorbing expansion valve 16b is a pressure reducing unit that reduces the pressure of the refrigerant at least in the heating mode and also functions to adjust the flow rate of the refrigerant flowing into the chiller 18. The basic configuration of the heat-absorbing expansion valve 16b is similar to that of the cooling expansion valve 16a. The refrigerant outlet side of the heat-absorbing expansion valve 16b is connected to the refrigerant inlet side of the chiller 18. The chiller 18 is a heat-absorbing evaporation unit that, at least in the heating mode, exchanges heat between the low-pressure refrigerant reduced in pressure by the heat-absorbing expansion valve 16b and the second heat medium circulating through the second heat medium circuit 30, thereby evaporating the low-pressure refrigerant and causing the refrigerant to absorb heat. The refrigerant outlet side of the chiller 18 is connected to the confluence unit 15b. The refrigerant outlet side of the confluence unit 15b is connected to the refrigerant suction side of the compressor 11.

[0029] The second heat medium circuit 30 is a low-temperature water circuit that circulates the second heat medium. The second heat medium is a fluid to be cooled by the refrigerant as it flows through the chiller 18. Examples of the second heat medium include a solution containing ethylene glycol and antifreeze. The second heat medium circuit 30 includes a second heat medium pump 31, a cooling unit for the on-board equipment 32, a second radiator 33, and a second flow control valve 34. The second heat medium pump 31 is a pump in the second heat medium circuit 30 that pressure-feeds the second heat medium to the water inlet side of the chiller 18. The second heat medium pump 31 has a basic configuration similar to that of the first heat medium pump 21. The on-board equipment 32 is a heat-generating device that generates heat during operation. In this embodiment, the on-board equipment 32 is a battery pack that supplies power to the traction motor. The cooling section of the on-board equipment 32 is a heat medium passage formed in the battery pack to allow the second heat medium to absorb heat generated by the battery pack during operation, such as charging and discharging. The second radiator 33 is formed, for example, integrally with the chiller 18 and disposed at the front side of the vehicle hood. The second radiator 33 is a heat exchanger that exchanges heat between the second heat medium cooled by the chiller 18 and outside air blown by an outside air fan, causing the second heat medium to absorb heat from the outside air. The cooling section of the on-board equipment 32 and the second radiator 33 are connected in parallel with the flow of the second heat medium in the second heat medium circuit 30. The second flow control valve 34 is a flow rate ratio adjustment unit that adjusts the flow rate ratio between the flow rate of the second heat medium flowing into the cooling section of the on-board equipment 32 and the flow rate of the second heat medium flowing into the second radiator 33. The basic configuration of the second flow control valve 34 is similar to that of the first flow control valve 24. When the second flow rate adjustment valve 34 adjusts the flow rate of the second heat medium flowing into the cooling section of the on-board equipment 32, the amount of heat absorbed from the on-board equipment 32 by the second heat medium in the cooling section of the on-board equipment 32, i.e., the cooling capacity of the cooling section of the on-board equipment 32, is adjusted.

[0030] Next, the interior air conditioning unit 50 will be described. The interior air conditioning unit 50 is located inside the instrument panel at the front of the vehicle interior. The interior air conditioning unit 50 forms an air passage for blowing temperature-controlled ventilation air to appropriate locations within the vehicle interior. The air passage inside the casing 51 houses a blower 52, an interior evaporator 17, an interior condenser 14, a heater core 22, etc.

[0031] An inside / outside air switching device 53 is disposed at the most upstream side of the blown air flow of the casing 51. The inside / outside air switching device 53 changes the ratio of inside air (i.e., air inside the vehicle cabin) and outside air (i.e., air outside the vehicle cabin) introduced into the casing 51. The inside / outside air switching device 53 has an inside / outside air switching door 53a formed by a plate door. The inside / outside air switching device 53 changes the ratio of inside air and outside air introduced by displacing the inside / outside air switching door 53a and continuously changing the ratio of the opening area of ​​the inside air inlet to the opening area of ​​the outside air inlet.

[0032] A blower 52 is disposed downstream of the inside / outside air switching device 53 in the flow of blown air. The blower 52 includes a centrifugal fan 52a and an electric motor 52b that generate an airflow. The blower 52 has its blowing capacity controlled by a control voltage output from the air conditioning control unit 60. Downstream of the blower 52 in the flow of blown air, the interior evaporator 17, the interior condenser 14, and the heater core 22 are disposed in this order with respect to the flow of blown air.

[0033] The interior evaporator 17 is disposed inside the casing 51 so that all of the ventilation air flowing through the ventilation passage in the casing 51 passes through the interior evaporator 17. The interior evaporator 17 may be disposed upstream of the blower 52.

[0034] A heating passage 50a, which directs the blown air to the interior condenser 14 and the heater core 22, and a bypass passage 50b, which directs the blown air bypassing both the interior condenser 14 and the heater core 22, are formed downstream of the interior evaporator 17. An air mix door 54 is disposed downstream of the interior evaporator 17 and upstream of the interior condenser 14. The air mix door 54 is an "air volume adjustment unit" that adjusts the ratio of the volume of the blown air passing through the heating passage 50a to the volume of the blown air passing through the bypass passage 50b after passing through the interior evaporator 17. The air mix door 54 includes an electric actuator, and its operation is controlled by a control signal output from the air conditioning control unit 60.

[0035] The casing 51 is provided at its most downstream airflow location with a defroster opening 57a, a face opening 57b, and a foot opening 57c, which blow conditioned air into the vehicle cabin. The defroster opening 57a is an opening for blowing conditioned air toward the inside surface of the vehicle's front windshield. A defroster door 57d is located upstream of the defroster opening 57a in the airflow direction, opening and closing the defroster opening 57a. The face opening 57b is an opening for blowing conditioned air toward the upper bodies of occupants in the vehicle cabin. A face door 57e is located upstream of the face opening 57b in the airflow direction, opening and closing the face opening 57b. The foot opening 57c is an opening for blowing conditioned air toward the feet of occupants. A foot door 57f is located upstream of the foot opening 57c in the airflow direction, opening and closing the foot opening 57c. The defroster door 57 d , face door 57 e , and foot door 57 f each include an electric actuator, and their operation is controlled by a control signal output from the air conditioning control unit 60 .

[0036] Next, an overview of the air conditioning control unit 60, which is an electrical control unit of the vehicle air conditioner 1, will be described with reference to Figure 3. The air conditioning control unit 60 is composed of a computer including a processor, ROM, RAM, and other memories, and its peripheral circuits. It performs various calculations and processes based on programs stored in the memory, and controls the operation of various controlled devices connected to the output side. The memory of the air conditioning control unit 60 is composed of a non-transitory physical storage medium.

[0037] As shown in FIG. 3 , an input side of the air conditioning control unit 60 is connected to an inside air temperature sensor 62a, an outside air temperature sensor 62b, a solar radiation sensor 62c, a high-pressure sensor 62d, a subcooling degree sensor 62e, an evaporator temperature sensor 62f, a superheat degree sensor 62g, and a blow-out temperature sensor 62h. Detection signals from various sensors are input to the air conditioning control unit 60. The inside air temperature sensor 62a is an inside air temperature detector that detects the temperature inside the vehicle cabin. The outside air temperature sensor 62b is an outside air temperature detector that detects the temperature outside the vehicle cabin. The solar radiation sensor 62c is an insolation amount detector that detects the amount of solar radiation irradiating the vehicle cabin. The high-pressure sensor 62d is a pressure detector that detects the pressure of the high-pressure refrigerant discharged from the compressor 11. The subcooling degree sensor 62e is a subcooling degree detector that detects the subcooling degree of the refrigerant flowing out of the interior condenser 14 or the subcooler SC based on the temperature and pressure of the refrigerant. The evaporator temperature sensor 62f is an evaporator temperature detector that detects the refrigerant evaporation temperature in the interior evaporator 17. The superheat degree sensor 62g is a superheat degree detector that detects the superheat degree of the low-pressure refrigerant drawn into the compressor 11 based on the temperature and pressure of the refrigerant. The outlet temperature sensor 62h is a temperature detector that detects the temperature of the air blown into the vehicle cabin from the interior air conditioning unit 50. Note that the evaporator temperature sensor 62f is not limited to detecting the temperature of the refrigerant flowing through the interior evaporator 17, and may be configured to detect the temperature of the air blown after passing through the interior evaporator 17 or the temperature of the interior evaporator 17 itself as the refrigerant evaporation temperature.

[0038] An operation panel 63 located near the instrument panel at the front of the vehicle interior is connected to the input side of the air conditioning control unit 60. The operation panel 63 is provided with an auto switch for setting the vehicle air conditioner 1 to automatic operation, a cooling switch for requesting cooling of the vehicle interior, an air volume setting switch for manually setting the air volume of the blower 52, a temperature setting switch for setting a target temperature for the vehicle interior, and the like. Operation signals are input to the air conditioning control unit 60 from the various operation switches provided on the operation panel 63. Note that the air conditioning control unit 60 is an integrated unit configured with control units for controlling various control target devices, and the hardware and software that control the operation of each control target device constitute the control unit that controls the operation of each control target device.

[0039] Next, the operation of the vehicle air conditioner 1 configured as described above will be described. As described above, the vehicle air conditioner 1 of this embodiment can switch between operating modes. The switching of operating modes is performed by executing a control program pre-stored in the air conditioning control unit 60. The air conditioning control unit 60 calculates a target blowing temperature of the air to be blown into the vehicle cabin based on, for example, detection signals detected by a group of air conditioning control sensors and operation signals output from the operation panel 63. The air conditioning control unit 60 then switches between operating modes based on the target blowing temperature and various detection signals. The air conditioning control unit 60 controls the operation of various control-target devices connected to the output side depending on the operating mode. The operation of each operating mode will be described below.

[0040] (A) Cooling Mode In the cooling mode, the air conditioning control unit 60 controls the operation of the compressor 11 so that the refrigerant evaporation temperature detected by the evaporator temperature sensor 62f becomes a target evaporation temperature. The target evaporation temperature is determined based on the target outlet temperature and by referring to a control map previously stored in the air conditioning control unit 60. The air conditioning control unit 60 also throttles the cooling expansion valve 16a and fully closes the heat absorption expansion valve 16b. For example, the air conditioning control unit 60 adjusts the throttle opening of the cooling expansion valve 16a so that the degree of superheat detected by the superheat sensor 62g approaches a predetermined reference degree of superheat (e.g., 3°C). As a result, the refrigeration cycle apparatus 10 functions as a refrigerant circuit that flows refrigerant decompressed by the cooling expansion valve 16a into the indoor evaporator 17.

[0041] The air conditioning control unit 60 controls the operation of the blower 52 so that the blowing capacity increases as the difference between the actual blowing temperature and the target blowing temperature increases. The air conditioning control unit 60 also displaces the air mix door 54 so that the actual blowing temperature approaches the target blowing temperature. For example, when the target blowing temperature is equal to or lower than a reference temperature set to be equal to or lower than the refrigerant evaporation temperature, the air conditioning control unit 60 displaces the air mix door 54 to the maximum cooling position so that the entire amount of cool air passing through the interior evaporator 37 flows into the bypass passage 50b. For example, when the target blowing temperature is higher than the refrigerant evaporation temperature, the air conditioning control unit 60 displaces the air mix door 54 to the intermediate opening position so that a portion of the cool air passing through the interior evaporator 37 flows into the heating passage 50a.

[0042] The air conditioning control unit 60 displaces the inside / outside air switching door 53a so that the outside air introduction mode is activated when the air mix door 54 is in an intermediate opening position, and displaces the inside / outside air switching door 53a so that the inside air introduction mode is activated when the air mix door 54 is in a maximum cooling position.

[0043] The air conditioning control unit 60 controls the operation of the refrigerant amount adjustment unit FR by the circuit control process shown in Fig. 4. As shown in Fig. 4, the air conditioning control unit 60 reads various signals in step S100, and then determines in step S110 whether the air mix door 54 is in the maximum cooling position. This determination may be made based on a control signal sent to the air mix door 54, or may be made based on the relationship between the target blown air temperature and the refrigerant evaporation temperature.

[0044] If the air mix door 54 is not in the maximum cooling position, the air conditioning control unit 60 controls the refrigerant amount adjustment unit FR in step S120 to switch to a circuit in which the refrigerant passes through the indoor condenser 14. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the indoor condenser 14.

[0045] On the other hand, when the air mix door 54 is in the maximum cooling position, the air conditioning control unit 60 controls the refrigerant amount adjustment unit FR in step S130 to switch to a refrigerant circuit that passes through the subcooler SC. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit that allows the refrigerant that has passed through the water-refrigerant heat exchanger 12 to flow into the subcooler SC.

[0046] The air conditioning control unit 60 operates the first heat medium pump 21 to achieve a predetermined water pumping capacity in the cooling mode. The air conditioning control unit 60 also controls the operation of the first flow rate control valve 24 depending on the door opening degree of the air mix door 54. For example, when the air mix door 54 is in an intermediate opening position, the air conditioning control unit 60 controls the operation of the first flow rate control valve 24 so that the first heat medium flowing out of the water-refrigerant heat exchanger 12 flows into both the first radiator 23 and the heater core 22. The air conditioning control unit 60 also controls the operation of the first flow rate control valve 24 so that the first heat medium flowing out of the water-refrigerant heat exchanger 12 flows into the first radiator 23 when the air mix door 54 is in the maximum cooling position.

[0047] Hereinafter, the cooling mode in which the air mix door 54 is displaced to the intermediate opening position will be referred to as a first cooling mode, and the cooling mode in which the air mix door 54 is displaced to the maximum cooling position will be referred to as a second cooling mode.

[0048] (A-1) First Cooling Mode In the refrigeration cycle apparatus 10 in the first cooling mode, as shown in FIG. 5 , high-pressure refrigerant discharged from the compressor 11 flows into the water-refrigerant heat exchanger 12. In the water-refrigerant heat exchanger 12, the first heat medium pump 21 is operating, and heat is exchanged between the high-pressure refrigerant and the first heat medium. The high-pressure refrigerant is cooled and condensed, and the first heat medium is heated. In this embodiment, the water-refrigerant heat exchanger 12 is configured as a subcooling condenser. Therefore, the high-pressure refrigerant is subcooled in the water-refrigerant heat exchanger 12. In the first heat medium circuit 20, the first heat medium heated in the water-refrigerant heat exchanger 12 flows into both the first radiator 23 and the heater core 22 via the first flow control valve 24. The first heat medium flows into the first radiator 23 to release heat to the outside air and into the heater core 22 to release heat to the blown air. This causes the temperature of the blown air to approach the target outlet temperature.

[0049] The refrigerant flowing out of the water-refrigerant heat exchanger 12 flows into the interior condenser 14. In the interior condenser 14, the high-pressure refrigerant exchanges heat with a portion of the blown air that has passed through the interior evaporator 17, thereby dissipating heat. This heats the blown air flowing into the interior condenser 14. The blown air that has passed through the interior condenser 14 and the heater core 22 is mixed with the cool air that has passed through the bypass passage 50b, adjusted to the desired temperature, and then blown into the vehicle cabin. Note that the refrigerant flowing into the interior condenser 14 is refrigerant that has been subcooled in the water-refrigerant heat exchanger 12. Therefore, the temperature of the blown air heated by the interior condenser 14 does not become higher than the temperature of the high-temperature heat medium flowing into the heater core 22.

[0050] The refrigerant flowing out of the interior condenser 14 flows into the cooling expansion valve 16a and is decompressed because the heat-absorbing expansion valve 16b is fully closed. At this time, the throttle opening of the cooling expansion valve 16a is controlled so that the superheat degree approaches a reference superheat degree. The low-pressure refrigerant decompressed by the cooling expansion valve 16a flows into the interior evaporator 17. The refrigerant flowing into the interior evaporator 17 absorbs heat from the blown air blown by the blower 52 and evaporates. This cools the blown air. The refrigerant flowing out of the interior evaporator 17 is drawn into the compressor 11 via the evaporation pressure control valve 19 and the second junction 15b and is compressed again.

[0051] As described above, in the first cooling mode, the blown air cooled by the interior evaporator 17 is reheated by the interior condenser 14 and the heater core 22 and then blown into the vehicle compartment, thereby cooling the vehicle compartment with cool air adjusted to an appropriate temperature. Note that in the first cooling mode, if either the interior condenser 14 or the heater core 22 can adjust the temperature of the blown air to the target blown air temperature, either the interior condenser 14 or the heater core 22 may heat the blown air.

[0052] (A-2) Second Cooling Mode In the refrigeration cycle apparatus 10 in the second cooling mode, as shown in FIG. 6 , high-pressure refrigerant discharged from the compressor 11 flows into the water-refrigerant heat exchanger 12. In the water-refrigerant heat exchanger 12, the first heat medium pump 21 is operating, and heat is exchanged between the high-pressure refrigerant and the first heat medium. The high-pressure refrigerant is cooled and condensed, and the first heat medium is heated. In this embodiment, the water-refrigerant heat exchanger 12 is configured as a subcooling condenser. Therefore, the high-pressure refrigerant is subcooled in the water-refrigerant heat exchanger 12. In the first heat medium circuit 20, the first heat medium heated in the water-refrigerant heat exchanger 12 flows into the first radiator 23 via the first flow control valve 24. The first heat medium flows into the first radiator 23 and dissipates heat to the outside air.

[0053] The refrigerant flowing out of the water-refrigerant heat exchanger 12 flows into the subcooler SC via the bypass section 13 rather than the indoor condenser 14. In the subcooler SC, the high-pressure refrigerant exchanges heat with a fluid other than the blown air (for example, outside air) and dissipates heat.

[0054] Because the heat-absorbing expansion valve 16b is fully closed, the refrigerant flowing out of the subcooler SC flows into the cooling expansion valve 16a and is decompressed. At this time, the throttle opening of the cooling expansion valve 16a is controlled so that the superheat degree approaches a reference superheat degree. The low-pressure refrigerant decompressed by the cooling expansion valve 16a flows into the interior evaporator 17. The refrigerant flowing into the interior evaporator 17 absorbs heat from the blown air blown by the blower 52 and evaporates. This cools the blown air. The blown air that has passed through the interior evaporator 17 passes through the bypass passage 50b and is then blown into the vehicle cabin. The refrigerant flowing out of the interior evaporator 17 is drawn into the compressor 11 via the evaporation pressure control valve 19 and the second junction 15b and is compressed again.

[0055] As described above, in the second cooling mode, the vehicle interior can be cooled by the blown air cooled by the interior evaporator 17. In the second cooling mode, high-temperature fluid does not flow into the interior condenser 14 and the heater core 22, and the fluid does not radiate heat to the blown air, so heat damage caused by the interior condenser 14 and the heater core 22 can be suppressed.

[0056] If the subcooler SC is not provided for the bypass portion 13, the refrigerant that has been supercooled in the water-refrigerant heat exchanger 12 is decompressed by the cooling expansion valve 16a, as shown by the broken line in FIG.

[0057] On the other hand, when the sub-cooler SC is provided for the bypass portion 13, the refrigerant that has been subcooled in the water-refrigerant heat exchanger 12 and the sub-cooler SC is decompressed by the air-conditioning expansion valve 16a, as shown by the solid line in Fig. 7. Therefore, in the second air-conditioning mode, the COP (= ΔH1 / ΔH3) during cooling can be made larger than when the sub-cooler SC is not provided for the bypass portion 13.

[0058] (B) Dehumidifying and Heating Mode In the dehumidifying and heating mode, the air conditioning control unit 60 controls the operation of the compressor 11 so that the refrigerant evaporation temperature detected by the evaporator temperature sensor 62f becomes the target evaporation temperature, as in the cooling mode. The air conditioning control unit 60 also controls the cooling expansion valve 16a to be throttled and the heat absorption expansion valve 16b to be fully closed. This allows the refrigeration cycle apparatus 10 to function as a refrigerant circuit that allows the refrigerant decompressed by the cooling expansion valve 16a to flow into the indoor evaporator 17.

[0059] The air conditioning control unit 60 controls the operation of the blower 52 in the same manner as in the cooling mode. The air conditioning control unit 60 displaces the air mix door 54 so that the degree of subcooling detected by the subcooling degree sensor 62e approaches the target degree of subcooling. The target degree of subcooling is determined based on the target blown air temperature and by referring to a control map stored in advance in the air conditioning control unit 60.

[0060] The air conditioning control unit 60 displaces the inside / outside air switching door 53a to switch to the outside air introduction mode. The air conditioning control unit 60 also controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes through the indoor condenser 14. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the indoor condenser 14.

[0061] The air conditioning control unit 60 operates the first heat medium pump 21 to exert a predetermined water pressure-feeding capacity in the dehumidifying heating mode. The air conditioning control unit 60 also controls the operation of the first flow rate adjustment valve 24 so that the blowing temperature of the blown air approaches the target blowing temperature.

[0062] In the refrigeration cycle apparatus 10 configured as described above in the dehumidifying and heating mode, as shown in FIG. 8 , high-pressure refrigerant discharged from the compressor 11 flows into the water-refrigerant heat exchanger 12. In the water-refrigerant heat exchanger 12, the first heat medium pump 21 is operating, and heat is exchanged between the high-pressure refrigerant and the first heat medium. The high-pressure refrigerant is cooled and condensed, and the first heat medium is heated. In this embodiment, the water-refrigerant heat exchanger 12 is configured as a subcooling condenser. Therefore, the high-pressure refrigerant is subcooled in the water-refrigerant heat exchanger 12. In the first heat medium circuit 20, the first heat medium heated in the water-refrigerant heat exchanger 12 flows into the heater core 22 via the first flow control valve 24. The first heat medium flows into the heater core 22 and dissipates heat to the blown air. This causes the temperature of the blown air to approach the target blown air temperature.

[0063] The refrigerant flowing out of the water-refrigerant heat exchanger 12 flows into the interior condenser 14. In the interior condenser 14, the high-pressure refrigerant exchanges heat with the blown air that has passed through the interior evaporator 17, thereby dissipating heat. As a result, the blown air flowing into the interior condenser 14 is heated. Note that the refrigerant flowing into the interior condenser 14 is refrigerant that has been subcooled in the water-refrigerant heat exchanger 12. Therefore, the temperature of the blown air heated in the interior condenser 14 does not become higher than the temperature of the high-temperature side heat medium flowing into the heater core 22.

[0064] The refrigerant flowing out from the interior condenser 14 flows into the cooling expansion valve 16a and is decompressed because the heat-absorbing expansion valve 16b is fully closed. At this time, the throttle opening of the cooling expansion valve 16a is controlled so that the superheat degree approaches a reference superheat degree. The low-pressure refrigerant decompressed by the cooling expansion valve 16a flows into the interior evaporator 17. The refrigerant flowing into the interior evaporator 17 absorbs heat from the blown air blown by the blower 52 and evaporates. This cools the blown air. The refrigerant flowing out from the interior evaporator 17 is drawn into the compressor 11 via the evaporation pressure control valve 19 and the second junction 15b and is compressed again.

[0065] As described above, in the dehumidifying and heating mode, the blown air cooled and dehumidified by the interior evaporator 17 is reheated by the interior condenser 14 and the heater core 22 and blown into the vehicle compartment, thereby heating the vehicle compartment with the dehumidified warm air. Note that in the dehumidifying and heating mode, both the cooling expansion valve 16a and the heat absorption expansion valve 16b may be throttled and the second heat medium pump 31 may be operated to absorb heat from the chiller 18 in addition to the interior evaporator 17. This increases the amount of heat absorbed by the refrigerant, thereby improving the heating capacity of the blown air.

[0066] (C) Heating Mode In the heating mode, the air conditioning control unit 60 controls the operation of the compressor 11 so that the pressure of the high-pressure refrigerant detected by the high-pressure sensor 62d becomes a target high pressure. The target high pressure is determined based on the target discharge temperature and by referring to a control map previously stored in the air conditioning control unit 60. The air conditioning control unit 60 also fully closes the cooling expansion valve 16a and throttles the heat absorption expansion valve 16b. As a result, the refrigeration cycle apparatus 10 in the heating mode becomes a refrigerant circuit that flows refrigerant decompressed by the heat absorption expansion valve 16b into the chiller 18. The air conditioning control unit 60 also adjusts the throttle opening of the heat absorption expansion valve 16b so that the degree of superheat approaches a predetermined reference degree of superheat.

[0067] The air conditioning control unit 60 operates the first heat medium pump 21 and the second heat medium pump 31 to exert a predetermined water pumping capacity in the heating mode. At this time, the air conditioning control unit 60 controls the operation of the first flow control valve 24 so that the entire flow rate of the first heat medium flowing out of the water-refrigerant heat exchanger 12 flows into the heater core 22. The air conditioning control unit 60 controls the operation of the second flow control valve 34 so that the entire flow rate of the second heat medium flowing out of the chiller 18 flows into the second radiator 33.

[0068] The air conditioning control unit 60 controls the operation of the blower 52 in the same manner as in the cooling mode. The air conditioning control unit 60 displaces the air mix door 54 so that the bypass passage 50b is closed and all of the blown air that has passed through the interior evaporator 17 flows into the interior condenser 14. The air conditioning control unit 60 also displaces the interior / exterior air switching door 53a of the interior / exterior air switching device 53 to switch to the exterior air mode. The air conditioning control unit 60 also controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes through the interior condenser 14. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the interior condenser 14.

[0069] In the refrigeration cycle apparatus 10 configured as above in the heating mode, as shown in FIG. 9 , high-pressure refrigerant discharged from the compressor 11 flows into the water-refrigerant heat exchanger 12. In the water-refrigerant heat exchanger 12, the first heat medium pump 21 is operating, and the high-pressure refrigerant and the first heat medium exchange heat, cooling and condensing the high-pressure refrigerant, and heating the first heat medium. In the first heat medium circuit 20, the first heat medium heated in the water-refrigerant heat exchanger 12 flows into the heater core 22 via the first flow control valve 24. The high-temperature side heat medium that flows into the heater core 22 exchanges heat with the blown air that has passed through the indoor condenser 14 and dissipates heat. This heats the blown air, bringing the temperature of the blown air closer to the target outlet temperature.

[0070] The refrigerant flowing out of the water-refrigerant heat exchanger 12 flows into the interior condenser 14. The refrigerant flowing into the interior condenser 14 exchanges heat with the blown air that has passed through the interior evaporator 17, thereby dissipating heat. As a result, the blown air flowing into the heater core 22 is heated.

[0071] The refrigerant flowing out from the indoor condenser 14 flows into the heat-absorbing expansion valve 16b and is decompressed because the cooling expansion valve 16a is fully closed. At this time, the throttle opening of the heat-absorbing expansion valve 16b is controlled so that the superheat degree approaches the reference superheat degree. The low-pressure refrigerant decompressed by the heat-absorbing expansion valve 16b flows into the chiller 18. The refrigerant flowing out from the chiller 18 is drawn into the compressor 11 via the second junction 15b and compressed again.

[0072] Here, in the chiller 18, the second heat medium pump 31 is operating, so that the low-pressure refrigerant and the second heat medium exchange heat, and the low-pressure refrigerant absorbs heat from the second heat medium and evaporates. This cools the second heat medium. In the second heat medium circuit 30, the second heat medium cooled by the chiller 18 flows into the second radiator 33 via the second flow control valve 34. The second heat medium that has flowed into the second radiator 33 exchanges heat with outside air and is heated.

[0073] As described above, in the heating mode, the vehicle interior can be heated by blowing the blown air heated in two stages into the vehicle interior, first through the interior condenser 14 and then through the heater core 22. In this heating mode, the COP (=ΔH2 / ΔH3) during heating can be increased compared to when the blown air is heated only by the heater core 22.

[0074] (D) Equipment Cooling Mode In the equipment cooling mode, the air conditioning control unit 60 controls the operation of the compressor 11 so as to achieve a predetermined refrigerant discharge capacity for the equipment cooling mode. The air conditioning control unit 60 also fully closes the cooling expansion valve 16a and throttles the heat absorption expansion valve 16b. As a result, the refrigeration cycle apparatus 10 in the equipment cooling mode operates as a refrigerant circuit that allows refrigerant decompressed by the heat absorption expansion valve 16b to flow into the chiller 18. The air conditioning control unit 60 also adjusts the throttle opening of the heat absorption expansion valve 16b so that the degree of superheat approaches a predetermined reference degree of superheat.

[0075] The air conditioning control unit 60 operates the first heat medium pump 21 and the second heat medium pump 31 to exert a predetermined water pressure-feeding capacity in the equipment cooling mode. At this time, the air conditioning control unit 60 controls the operation of the first flow control valve 24 so that the entire flow rate of the first heat medium flowing out of the water-refrigerant heat exchanger 12 flows into the first radiator 23. The air conditioning control unit 60 controls the operation of the second flow control valve 34 so that the entire flow rate of the second heat medium flowing out of the chiller 18 flows into the cooling unit of the on-vehicle equipment 32.

[0076] The air conditioning control unit 60 stops the operation of the blower 52 so that blown air does not flow into the interior condenser 14 or the heater core 22, and does not particularly displace the air mix door 54 or the inside / outside air switching door 53a. The air conditioning control unit 60 controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes through the subcooler SC. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the subcooler SC.

[0077] In the refrigeration cycle apparatus 10 in the equipment cooling mode configured as described above, as shown in Fig. 10, high-pressure refrigerant discharged from the compressor 11 flows into the water-refrigerant heat exchanger 12. In the water-refrigerant heat exchanger 12, the first heat medium pump 21 is operating, and therefore the high-pressure refrigerant and the first heat medium exchange heat, cooling and condensing the high-pressure refrigerant, and heating the first heat medium. In the first heat medium circuit 20, the first heat medium heated in the water-refrigerant heat exchanger 12 flows into the first radiator 23 via the first flow control valve 24. The first heat medium that has flowed into the first radiator 23 exchanges heat with outside air and dissipates heat.

[0078] The refrigerant flowing out of the water-refrigerant heat exchanger 12 flows into the subcooler SC via the bypass section 13 rather than the indoor condenser 14. In the subcooler SC, the high-pressure refrigerant exchanges heat with a fluid other than the blown air (for example, outside air) and dissipates heat.

[0079] The refrigerant flowing out of the subcooler SC flows into the heat-absorbing expansion valve 16b and is decompressed because the cooling expansion valve 16a is fully closed. At this time, the throttle opening of the heat-absorbing expansion valve 16b is controlled so that the superheat degree approaches the reference superheat degree. The low-pressure refrigerant decompressed by the heat-absorbing expansion valve 16b flows into the chiller 18. The refrigerant flowing out of the chiller 18 is drawn into the compressor 11 via the second junction 15b and compressed again.

[0080] In the chiller 18, the second heat medium pump 31 is operating, so that the low-pressure refrigerant and the second heat medium exchange heat, and the low-pressure refrigerant absorbs heat from the second heat medium and evaporates. This cools the second heat medium. In the second heat medium circuit 30, the second heat medium cooled by the chiller 18 flows into the cooling section of the on-board equipment 32 via the second flow control valve 34. The on-board equipment 32 is cooled by heat exchange with the second heat medium.

[0081] As described above, in the equipment cooling mode, the on-board equipment 32 can be cooled by the low-temperature second heat medium flowing through the second heat medium circuit 30. In particular, in the equipment cooling mode, the refrigerant that has been subcooled in the water-refrigerant heat exchanger 12 and the subcooler SC is decompressed by the heat-absorbing expansion valve 16b. Therefore, in the equipment cooling mode, the COP (=ΔH1 / ΔH3) during equipment cooling can be made larger than in a case where the subcooler SC is not provided in the bypass portion 13.

[0082] (E) Cooling & Equipment Cooling Mode In the cooling & equipment cooling mode, the air conditioning control unit 60 controls the compressor 11, the first heat medium pump 21, the first flow control valve 24, the blower 52, the inside / outside air switching door 53 a, the air mix door 54, etc. in the same manner as in the cooling mode.

[0083] Meanwhile, the air conditioning control unit 60 throttles both the cooling expansion valve 16 a and the heat absorption expansion valve 16 b, thereby causing the refrigeration cycle device 10 to operate as a refrigerant circuit in which the refrigerant decompressed by the cooling expansion valve 16 a flows into the indoor evaporator 17, and the refrigerant decompressed by the heat absorption expansion valve 16 b flows into the chiller 18.

[0084] The air conditioning control unit 60 controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes through the sub-cooler SC. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the sub-cooler SC. The air conditioning control unit 60 also operates the first heat medium pump 21 and the second heat medium pump 31 to exert a predetermined water pumping capacity in the equipment cooling mode.

[0085] In the refrigeration cycle apparatus 10 in the cooling and equipment cooling mode configured as above, for example, as shown in Fig. 11 , high-pressure refrigerant discharged from the compressor 11 flows into the water-refrigerant heat exchanger 12. In the water-refrigerant heat exchanger 12, the first heat medium pump 21 is operating, so that the high-pressure refrigerant and the first heat medium exchange heat, the high-pressure refrigerant is cooled and condensed, and the first heat medium is heated. In the first heat medium circuit 20, the first heat medium heated in the water-refrigerant heat exchanger 12 flows into the first radiator 23 via the first flow control valve 24. The first heat medium that flows into the first radiator 23 exchanges heat with outside air and dissipates heat.

[0086] The refrigerant flowing out of the water-refrigerant heat exchanger 12 flows into the subcooler SC via the bypass section 13 rather than the indoor condenser 14. In the subcooler SC, the high-pressure refrigerant exchanges heat with a fluid other than the blown air (for example, outside air) and dissipates heat.

[0087] The refrigerant flowing out of the subcooler SC flows into both the cooling expansion valve 16 a and the heat absorption expansion valve 16 b, and is reduced in pressure, because both the cooling expansion valve 16 a and the heat absorption expansion valve 16 b are in a throttled state. The throttle openings of the expansion valves 16 a and 16 b are controlled so that the degree of superheat approaches the reference degree of superheat.

[0088] Specifically, the low-pressure refrigerant decompressed by the cooling expansion valve 16a flows into the interior evaporator 17. The refrigerant that flows into the interior evaporator 17 absorbs heat from the air blown by the blower 52 and evaporates, thereby cooling the air. The refrigerant that flows out of the interior evaporator 17 is drawn into the compressor 11 via the evaporation pressure control valve 19 and the second junction 15b and is compressed again.

[0089] Meanwhile, the low-pressure refrigerant decompressed by the heat-absorbing expansion valve 16b flows into the chiller 18. The refrigerant flowing out of the chiller 18 is drawn into the compressor 11 via the second junction 15b and compressed again. In the chiller 18, the second heat medium pump 31 is operating, so that the low-pressure refrigerant and the second heat medium exchange heat, and the low-pressure refrigerant absorbs heat from the second heat medium and evaporates. This cools the second heat medium. In the second heat medium circuit 30, the second heat medium cooled by the chiller 18 flows into the cooling section of the on-board equipment 32 via the second flow control valve 34. The on-board equipment 32 is cooled by heat exchange with the second heat medium.

[0090] As described above, in the cooling and equipment cooling mode, the blown air cooled by the low-pressure refrigerant flowing through the interior evaporator 17 is blown into the vehicle compartment, while the low-temperature second heat medium flowing through the second heat medium circuit 30 cools the on-board equipment 32. In particular, in the cooling and equipment cooling mode, the refrigerant that has been subcooled in the water-refrigerant heat exchanger 12 and the subcooler SC is decompressed by the expansion valves 16a, 16b. Therefore, in the cooling and equipment cooling mode, the COP (=ΔH1 / ΔH3) during equipment cooling can be made larger than in a case where the subcooler SC is not provided in the bypass unit 13.

[0091] (F) Dehumidifying Heating & Equipment Cooling Mode In the dehumidifying heating & equipment cooling mode, the air conditioning control unit 60 controls the compressor 11, the first heat medium pump 21, the first flow control valve 24, the blower 52, the inside / outside air switching door 53 a, the air mix door 54, etc. in the same manner as in the dehumidifying heating mode.

[0092] Meanwhile, the air conditioning control unit 60 throttles both the cooling expansion valve 16 a and the heat absorption expansion valve 16 b, thereby causing the refrigeration cycle device 10 to operate as a refrigerant circuit in which the refrigerant decompressed by the cooling expansion valve 16 a flows into the indoor evaporator 17, and the refrigerant decompressed by the heat absorption expansion valve 16 b flows into the chiller 18.

[0093] The air conditioning control unit 60 controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes through the indoor condenser 14. As a result, the refrigeration cycle device 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the indoor condenser 14. The air conditioning control unit 60 also operates the first heat medium pump 21 and the second heat medium pump 31 to exert a predetermined water pumping capacity in the equipment cooling mode.

[0094] Here, when the first heat medium heated in the water-refrigerant heat exchanger 12 is caused to flow only into the heater core 22, the heating performance in the vehicle cabin is improved compared to when the first heat medium is caused to flow into both the first radiator 23 and the heater core 22. Hereinafter, when the first heat medium is caused to flow into both the heater core 22 and the interior condenser 14, this will be referred to as a first dehumidifying heating & equipment cooling mode, and when the first heat medium is caused to flow into only the heater core 22, this will be referred to as a second dehumidifying heating & equipment cooling mode.

[0095] (F-1) First Dehumidifying Heating & Equipment Cooling Mode In the refrigeration cycle device 10 in the first dehumidifying heating & equipment cooling mode, as shown in FIG. 12 , for example, high-pressure refrigerant discharged from the compressor 11 flows into the water-refrigerant heat exchanger 12. In the water-refrigerant heat exchanger 12, the first heat medium pump 21 is operating, and the high-pressure refrigerant and the first heat medium exchange heat, cooling and condensing the high-pressure refrigerant, and heating the first heat medium. In the first heat medium circuit 20, the first heat medium heated in the water-refrigerant heat exchanger 12 flows into both the first radiator 23 and the heater core 22 via the first flow control valve 24. The first heat medium that flows into the first radiator 23 exchanges heat with outside air and dissipates heat. The first heat medium that flows into the heater core 22 exchanges heat with the blown air and dissipates heat.

[0096] The refrigerant flowing out of the water-refrigerant heat exchanger 12 flows into the interior condenser 14. In the interior condenser 14, the high-pressure refrigerant exchanges heat with the blown air and dissipates heat, thereby heating the blown air flowing into the interior condenser 14.

[0097] The refrigerant flowing out from the indoor condenser 14 flows into both the cooling expansion valve 16a and the heat absorption expansion valve 16b, and is reduced in pressure, because both the cooling expansion valve 16a and the heat absorption expansion valve 16b are in a throttled state. The throttle opening of each expansion valve 16a, 16b is controlled so that the degree of superheat approaches the reference degree of superheat.

[0098] The low-pressure refrigerant decompressed by the cooling expansion valve 16a flows into the interior evaporator 17. The refrigerant that flows into the interior evaporator 17 absorbs heat from the air blown by the blower 52 and evaporates, thereby cooling the air. The refrigerant that flows out of the interior evaporator 17 is drawn into the compressor 11 via the evaporation pressure control valve 19 and the second junction 15b and is compressed again.

[0099] Meanwhile, the low-pressure refrigerant decompressed by the heat-absorbing expansion valve 16b flows into the chiller 18. The refrigerant flowing out of the chiller 18 is drawn into the compressor 11 via the second junction 15b and compressed again. In the chiller 18, the second heat medium pump 31 is operating, so that the low-pressure refrigerant and the second heat medium exchange heat, and the low-pressure refrigerant absorbs heat from the second heat medium and evaporates. This cools the second heat medium. In the second heat medium circuit 30, the second heat medium cooled by the chiller 18 flows into the cooling section of the on-board equipment 32 via the second flow control valve 34. The on-board equipment 32 is cooled by heat exchange with the second heat medium.

[0100] As described above, in the first dehumidifying heating & equipment cooling mode, the blown air that has been cooled and dehumidified by the low-pressure refrigerant flowing through the interior evaporator 17 is heated by the interior condenser 14 and the heater core 22 and then blown into the vehicle cabin. In addition, in the first dehumidifying heating & equipment cooling mode, the low-temperature second heat medium flowing through the second heat medium circuit 30 can cool the on-board equipment 32.

[0101] (F-2) Second Dehumidifying Heating & Equipment Cooling Mode In the refrigeration cycle device 10 in the first dehumidifying heating & equipment cooling mode, for example, as shown in FIG. 13 , high-pressure refrigerant discharged from the compressor 11 flows into the water-refrigerant heat exchanger 12. In the water-refrigerant heat exchanger 12, the first heat medium pump 21 is operating, and the high-pressure refrigerant and the first heat medium exchange heat. The high-pressure refrigerant is cooled and condensed, and the first heat medium is heated. In the first heat medium circuit 20, the first heat medium heated in the water-refrigerant heat exchanger 12 flows only into the heater core 22 via the first flow control valve 24. The first heat medium that flows into the heater core 22 exchanges heat with the blown air and dissipates heat. The refrigerant that flows out of the water-refrigerant heat exchanger 12 flows into the indoor condenser 14. The subsequent operation is similar to that in the first dehumidifying heating & equipment cooling mode, and therefore a description thereof will be omitted.

[0102] As described above, in the second dehumidifying heating & equipment cooling mode, the blown air that has been cooled and dehumidified by the low-pressure refrigerant flowing through the interior evaporator 17 is heated by the interior condenser 14 and the heater core 22 and then blown into the vehicle cabin. In addition, in the second dehumidifying heating & equipment cooling mode, the low-temperature second heat medium flowing through the second heat medium circuit 30 can cool the on-board equipment 32. In particular, in the second dehumidifying heating & equipment cooling mode, the first heat medium is dissipated only by the heater core 22, so that higher heating performance can be achieved compared to the first dehumidifying heating & equipment cooling mode.

[0103] The refrigeration cycle device 10 described above includes a first heating unit that heats the air to be blown into the space to be air-conditioned using the refrigerant discharged from the compressor 11 as a heat source, and a second heating unit that heats the air to be blown using the refrigerant that has passed through the first heating unit as a heat source. The provision of such a first heating unit and a second heating unit ensures sufficient heating performance.

[0104] Additionally, the refrigeration cycle apparatus 10 includes a bypass section 13 that allows the refrigerant, after passing through the first heating section, to bypass the second heating section, and a refrigerant amount adjustment section FR that adjusts the flow rate ratio of the refrigerant passing through the second heating section and the refrigerant passing through the bypass section 13. The refrigerant amount adjustment section FR adjusts the flow rate ratio so that the refrigerant passes through the second heating section when heating of the blown air by the second heating section is required, and adjusts the flow rate ratio so that the refrigerant passes through the bypass section 13 when heating of the blown air by the second heating section is not required. As a result, when heating of the blown air by the second heating section is not required, the refrigerant, after passing through the first heating section, bypasses the second heating section, thereby suppressing thermal damage caused by the second heating section. The refrigeration cycle apparatus 10 of this embodiment also has the following features.

[0105] (1) The refrigeration cycle apparatus 10 includes a subcooler SC that dissipates heat from the refrigerant flowing through the bypass unit 13 to a fluid other than the blown air. This allows the subcooler SC to reduce the enthalpy of the refrigerant after passing through the first heating unit, even when heating of the blown air by the second heating unit is not required, thereby increasing the cooling capacity of the blown air in the indoor evaporator 17.

[0106] (2) The first heating section includes a heater core 22 that transfers heat from the refrigerant discharged from the compressor 11 through a first heat medium to the blown air. The second heating section includes an interior condenser 14 that transfers heat from the refrigerant that has passed through the first heating section to the blown air. The interior condenser 14 is located upstream of the heater core 22 in the ventilation passage within the casing 51 so that the blown air that has passed through the interior condenser 14 can flow into the heater core 22. This allows the blown air that has been heated by the second heating section to be further heated by the first heating section (i.e., two-stage heating), thereby efficiently and sufficiently raising the temperature of even relatively low-temperature blown air. Furthermore, in this embodiment, the blown air can be heated only by the first heating section (i.e., single-stage heating), allowing for stepwise heating of the blown air.

[0107] (3) The refrigeration cycle device 10 includes an indoor evaporator 17 as an evaporation unit that evaporates a refrigerant, which cools the blown air using the latent heat of vaporization of the refrigerant after the refrigerant has been decompressed by the air-conditioning expansion valve 16a that constitutes the pressure reduction unit. The indoor condenser 14 is disposed downstream of the indoor evaporator 17 in the ventilation passage within the casing 51 so that at least a portion of the blown air that has passed through the indoor evaporator 17 can flow in. This allows the blown air that has been cooled and dehumidified by the indoor evaporator 17 to be reheated by the indoor condenser 14, etc.

[0108] (4) The interior condenser 14 has a refrigerant flow path configured so that the direction of the refrigerant flowing through the portion of the interior condenser 14 facing the heater core 22 is opposite to the direction of the first heat medium flowing through the portion of the heater core 22 facing the interior condenser 14. This allows the temperature distribution of the blown air that occurs when passing through the interior condenser 14 to be alleviated when passing through the heater core 22.

[0109] (5) When the operating state is such that the volume of the blown air passing through the heater core 22 is minimized and the volume of the blown air bypassing the heater core 22 is maximized, the air conditioning control unit 60 determines that heating of the blown air by the second heating unit is unnecessary. When heating of the blown air by the second heating unit is unnecessary, the air conditioning control unit 60 controls the refrigerant amount adjustment unit FR so that the refrigerant after passing through the water-refrigerant heat exchanger 12 passes through the bypass unit 13.

[0110] If the refrigerant amount adjustment unit FR frequently switches the flow path of the refrigerant after passing through the first heating unit, the temperature of the air blown into the air-conditioned space becomes unstable due to control hunting, etc. This is undesirable because it increases the discomfort of the user.

[0111] In contrast, when the unit enters a specific operating state in which heating of the blown air by the second heating unit is not required, the frequency of switching the refrigerant flow path can be reduced by adjusting the refrigerant flow rate so that the refrigerant that has passed through the first heating unit passes through the bypass unit 13. This makes it easier to stabilize the blown air temperature that is blown into the air-conditioned space, thereby reducing user discomfort caused by unstable blown air temperature.

[0112] (Modification of First Embodiment) In the first embodiment, the refrigerant amount adjustment unit FR is configured as a three-way valve provided in the first branch portion 13a, but is not limited to this. For example, the refrigerant amount adjustment unit FR may be configured as two open / close solenoid valves SV1 and SV2 as shown in FIG.

[0113] Second Embodiment Next, a second embodiment will be described with reference to Fig. 15. In this embodiment, differences from the first embodiment will be mainly described.

[0114] 15, the refrigeration cycle apparatus 10 includes an internal heat exchanger IHX that exchanges heat between the high-pressure refrigerant that has passed through the subcooler SC and the refrigerant that has passed through the indoor evaporator 17. The internal heat exchanger IHX has a high-pressure side heat exchange section HX through which the high-pressure refrigerant flows and a low-pressure side heat exchange section LX through which the low-pressure refrigerant flows.

[0115] When the blown air is heated by the indoor condenser 14, the cool air that has passed through the indoor evaporator 17 passes through the indoor condenser 14, which reduces the effect of heat exchange between the high-pressure refrigerant and the low-pressure refrigerant in the internal heat exchanger IHX. In consideration of this, in this embodiment, the high-pressure side heat exchange unit HX is provided between the subcooler SC and the first junction 13b, and the low-pressure side heat exchange unit LX is provided between the evaporation pressure control valve 19 and the second junction 15b.

[0116] The other points are the same as those of the first embodiment. The refrigeration cycle device 10 of the present embodiment can obtain the same effects as those of the first embodiment that are achieved by the configuration common to or equivalent to that of the first embodiment.

[0117] The refrigeration cycle apparatus 10 of this embodiment also has the following features: (1) The refrigeration cycle apparatus 10 includes an internal heat exchanger IHX that exchanges heat between the high-pressure refrigerant that has passed through the subcooler SC and the refrigerant that has passed through the interior evaporator 17. This allows the refrigerant that has passed through the interior evaporator 17 to reduce the enthalpy of the refrigerant that has passed through the subcooler SC, thereby increasing the cooling capacity when the interior evaporator 17 cools the fluid to be cooled.

[0118] (Modification of Second Embodiment) In the internal heat exchanger IHX of the second embodiment, the high-pressure side heat exchange section HX is provided between the subcooler SC and the first junction 13b, and the low-pressure side heat exchange section LX is provided between the indoor evaporator 17 and the second junction 15b, but this is not limiting. For example, as shown in Fig. 16 , the high-pressure side heat exchange section HX may be provided between the first junction 13b and the second branch section 15a, and the low-pressure side heat exchange section LX may be provided between the second junction 15b and the compressor 11.

[0119] Third Embodiment Next, a third embodiment will be described. In this embodiment, differences from the first embodiment will be mainly described. FIG. 17 is a flowchart showing the flow of the circuit control process executed by the air conditioning control unit 60 of this embodiment. The circuit control process executed by the air conditioning control unit 60 of this embodiment will be described below with reference to FIG. 17.

[0120] 17, the air conditioning control unit 60 reads various signals in step S200, and then determines in step S210 whether the air mix door 54 is in the maximum cooling position. This determination may be made based on a control signal to the air mix door 54, or may be made based on the relationship between the target blown air temperature and the refrigerant evaporation temperature.

[0121] If the air mix door 54 is not in the maximum cooling position, the air conditioning control unit 60 controls the refrigerant amount adjustment unit FR in step S220 to switch to a circuit in which the refrigerant passes through the indoor condenser 14. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the indoor condenser 14.

[0122] On the other hand, when the air mix door 54 is in the maximum cooling position, the air conditioning control unit 60 determines in step S230 whether the rotation speed of the compressor 11 is at its maximum. If the rotation speed of the compressor 11 is not at its maximum, the process proceeds to step S220, where the air conditioning control unit 60 controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes through the indoor condenser 14.

[0123] Furthermore, when the rotation speed of the compressor 11 is at its maximum, it is considered that heating of the blown air by the second heating unit is unnecessary. Therefore, when the rotation speed of the compressor 11 is at its maximum, the air conditioning control unit 60 proceeds to step S240 and controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes through the subcooler SC. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the subcooler SC.

[0124] The other points are the same as those of the first embodiment. The refrigeration cycle device 10 of the present embodiment can obtain the same effects as those of the first embodiment that are achieved by the configuration common to or equivalent to that of the first embodiment.

[0125] The refrigeration cycle apparatus 10 of this embodiment also has the following features. (1) When the air mix door 54 is in the maximum cooling position and the compressor 11 is in an operating state where its rotation speed is at its maximum, the air conditioning control unit 60 determines that heating of the blown air by the second heating unit is unnecessary. When heating of the blown air by the second heating unit is unnecessary, the air conditioning control unit 60 controls the refrigerant amount adjustment unit FR so that the refrigerant after passing through the water-refrigerant heat exchanger 12 passes through the bypass unit 13. This also reduces the frequency of switching the refrigerant flow path. Therefore, the blown air temperature of the blown air blown into the air-conditioned space is more likely to be stabilized, thereby reducing user discomfort caused by unstable blown air temperature.

[0126] (Fourth embodiment) Next, a fourth embodiment will be described. In this embodiment, differences from the third embodiment will be mainly described. FIG. 18 is a flowchart showing the flow of the circuit control process executed by the air conditioning control unit 60 of this embodiment. The circuit control process executed by the air conditioning control unit 60 of this embodiment will be described below with reference to FIG. 18.

[0127] 18, the air conditioning control unit 60 reads various signals in step S300, and then determines in step S310 whether the air mix door 54 is in the maximum cooling position. This determination may be made based on a control signal to the air mix door 54, or may be made based on the relationship between the target blown air temperature and the refrigerant evaporation temperature.

[0128] If the air mix door 54 is not in the maximum cooling position, the air conditioning control unit 60 controls the refrigerant amount adjustment unit FR in step S320 to switch to a circuit in which the refrigerant passes through the indoor condenser 14. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the indoor condenser 14.

[0129] On the other hand, if the air mix door 54 is in the maximum cooling position, the air conditioning control unit 60 determines in step S330 whether the rotation speed of the compressor 11 is at its maximum. If the rotation speed of the compressor 11 is not at its maximum, the process proceeds to step S320, where the air conditioning control unit 60 controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes through the indoor condenser 14.

[0130] Furthermore, when the rotation speed of the compressor 11 is at its maximum, the air conditioning control unit 60 determines in step S340 whether the refrigerant evaporation temperature is equal to or lower than a predetermined reference value. When the refrigerant evaporation temperature exceeds the predetermined reference value, the air conditioning control unit 60 proceeds to step S350 and controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes through both the subcooler SC and the indoor condenser 14. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant after passing through the water-refrigerant heat exchanger 12 flows into both the subcooler SC and the indoor condenser 14.

[0131] On the other hand, if the refrigerant evaporation temperature is equal to or lower than the predetermined reference value, the air conditioning control unit 60 proceeds to step S360 and controls the refrigerant amount adjustment unit FR to switch to a circuit in which the refrigerant passes only through the subcooler SC. As a result, the refrigeration cycle apparatus 10 becomes a refrigerant circuit in which the refrigerant that has passed through the water-refrigerant heat exchanger 12 flows into the subcooler SC.

[0132] The other points are the same as those of the third embodiment. The refrigeration cycle device 10 of the present embodiment can obtain the same effects as those of the third embodiment, which are achieved by the configuration common to or equivalent to that of the first embodiment.

[0133] The refrigeration cycle apparatus 10 of this embodiment also has the following features. (1) The air conditioning control unit 60 controls the refrigerant amount adjustment unit FR in accordance with the refrigerant evaporation temperature. Specifically, the air conditioning control unit 60 controls the refrigerant amount adjustment unit FR so that the amount of refrigerant flowing into the sub-cooler SC increases as the refrigerant evaporation temperature decreases. In this way, by controlling the refrigerant amount adjustment unit FR so that the amount of refrigerant flowing into the indoor condenser 14 and the sub-cooler SC gradually changes, the discharge temperature of the air blown into the air-conditioned space tends to be stabilized. Therefore, user discomfort caused by unstable discharge temperature can be reduced.

[0134] Fifth Embodiment Next, a fifth embodiment will be described with reference to Fig. 19. In this embodiment, differences from the first embodiment will be mainly described.

[0135] 19, the interior condenser 14 of this embodiment is disposed in the ventilation passage within the casing 51 so that the entire amount of blown air that has passed through the interior evaporator 17 passes through the interior condenser 14. Specifically, the interior condenser 14 is disposed downstream of the interior evaporator 17 within the casing 51 and upstream of the heating passage 50a and the bypass passage 50b.

[0136] The heater core 22 is disposed in the heating passage 50a. An air mix door 54 is disposed between the interior condenser 14 and the heater core 22. In this embodiment, the air mix door 54 constitutes an "air volume adjustment unit" that adjusts the ratio of the volume of the blown air passing through the heater core 22 to the volume of the blown air passing through the bypass passage 50b.

[0137] The other points are the same as those of the first embodiment. The refrigeration cycle device 10 of the present embodiment can obtain the same effects as those of the first embodiment that are achieved by the configuration common to or equivalent to that of the first embodiment.

[0138] Here, in the refrigeration cycle device 10 of the first embodiment, the ventilation passage within the casing 51 is divided into a passage that flows the blown air to the indoor condenser 14 and a passage that flows the blown air bypassing the indoor condenser 14, and the air volume ratio of the blown air flowing through each passage is adjusted by the air mix door 54.

[0139] In this configuration, when one passage is opened and the other is closed by the air mix door 54, the passage through which the ventilation air passes becomes narrower, resulting in a large pressure loss of the ventilation air. Furthermore, if each passage is enlarged in order to reduce the pressure loss of the ventilation air, the overall size of the ventilation system equipment would become significantly larger.

[0140] In contrast, in the refrigeration cycle device 10 of this embodiment, the indoor condenser 14 is disposed in the ventilation path so that the entire amount of ventilation air that has passed through the indoor evaporator 17 passes through the indoor condenser 14. This makes it possible to reduce pressure loss of the ventilation air without increasing the size of the entire ventilation system equipment.

[0141] Sixth Embodiment Next, a sixth embodiment will be described with reference to Fig. 20. In this embodiment, differences from the fifth embodiment will be mainly described.

[0142] 20, the interior condenser 14 and the heater core 22 of this embodiment are disposed in an air passage in the casing 51 so that the entire amount of blown air that has passed through the interior evaporator 17 passes through the air passage. Note that the casing 51 of this embodiment does not include the bypass passage 50b and the air mix door 54.

[0143] The rest of the configuration is the same as that of the fifth embodiment. The refrigeration cycle device 10 of the present embodiment can obtain the same effects as those of the fifth embodiment, which are achieved by the configuration common to or equivalent to that of the fifth embodiment.

[0144] The refrigeration cycle apparatus 10 of this embodiment also has the following features: (1) In the refrigeration cycle apparatus 10 of this embodiment, the indoor condenser 14 and the heater core 22 are disposed in the ventilation path so that the entire amount of ventilation air that has passed through the indoor evaporator 17 passes through both the indoor condenser 14 and the heater core 22. This makes it possible to reduce pressure loss of the ventilation air without increasing the overall size of the ventilation system equipment.

[0145] Other Embodiments Although typical embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be modified in various ways, for example, as follows.

[0146] As in the above-described embodiment, the bypass unit 13 is preferably disposed outside the casing 51, but is not limited to this. The bypass unit 13 may be disposed inside the casing 51. Furthermore, the refrigeration cycle apparatus 10 is preferably provided with a subcooler SC, but is not limited to this, and the subcooler SC may be omitted.

[0147] The first heating section in the above-described embodiment is configured to dissipate heat from the high-pressure refrigerant to the blown air via the first heat medium, but is not limited to this and may be configured to dissipate heat from the high-pressure refrigerant directly to the blown air, like the second heating section.

[0148] The second heating section in the above-described embodiment is configured to directly dissipate heat from the high-pressure refrigerant into the blown air, but is not limited to this. Like the first heating section, it may be configured to indirectly dissipate heat from the high-pressure refrigerant into the blown air via another fluid such as a first heat medium.

[0149] In the above-described embodiment, the indoor condenser 14 is disposed upstream of the heater core 22, but the refrigeration cycle apparatus 10 is not limited to this. For example, the refrigeration cycle apparatus 10 may be disposed such that the indoor condenser 14 and the heater core 22 are parallel to the flow of the blown air.

[0150] The air conditioning control unit 60 in the above-described embodiment is configured to determine whether or not heating of the blown air by the second heating unit is necessary depending on the opening degree of the air mix door 54. However, the present invention is not limited to this. For example, the air conditioning control unit 60 may be configured to determine that heating of the blown air by the second heating unit is unnecessary when heating of the vehicle interior is unnecessary.

[0151] The refrigeration cycle apparatus 10 of the above-described embodiment is configured such that the receiver 121b is provided in the water-refrigerant heat exchanger 12, but is not limited thereto, and the receiver 121b may be omitted. Furthermore, the refrigeration cycle apparatus 10 may be configured such that, for example, an accumulator is provided on the refrigerant suction side of the compressor 11 instead of the receiver 121b.

[0152] In the above-described embodiment, an example in which the refrigeration cycle device 10 of the present disclosure is applied to a vehicle air conditioner 1 is described, but this is not limited to this, and the refrigeration cycle device 10 can also be applied to air conditioners other than the vehicle air conditioner 1, for example.

[0153] In the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential unless they are specifically stated as essential or are clearly considered essential in principle.

[0154] In the above-described embodiments, when numerical values ​​such as the number, values, amounts, ranges, etc. of components of the embodiments are mentioned, they are not limited to the specific numbers unless they are specifically stated as essential or are clearly limited to a specific number in principle.

[0155] In the above-described embodiments, when referring to the shapes, positional relationships, etc. of components, etc., the shapes, positional relationships, etc. are not limited to those unless otherwise specified or when they are fundamentally limited to specific shapes, positional relationships, etc.

[0156] The controller and method of the present disclosure may be implemented on a special-purpose computer by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. The controller and method of the present disclosure may be implemented on a special-purpose computer by configuring a processor with one or more dedicated hardware logic circuits. The controller and method of the present disclosure may be implemented on one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. The computer program may also be stored on a computer-readable non-transitory tangible storage medium as instructions executed by a computer.

[0157] [Aspects of the present disclosure] [First aspect] A refrigeration cycle device applicable to an air conditioner (1), comprising: a compressor (11) that compresses and discharges a refrigerant; a first heating section (12, 20, 21, 22, 24) that uses the refrigerant discharged from the compressor as a heat source to heat blown air to be blown to a space to be air-conditioned; a second heating section (14) that uses the refrigerant after passing through the first heating section as a heat source to heat the blown air; a bypass section (13) that causes the refrigerant after passing through the first heating section to bypass the second heating section; a refrigerant amount adjustment section (FR) that adjusts the flow rate ratio of the refrigerant passing through the second heating section and the refrigerant passing through the bypass section; decompression sections (16a, 16b) that decompress the refrigerant after passing through the second heating section; and an evaporation section (17, 18) that evaporates the refrigerant after being decompressed by the decompression section by heat exchange with a fluid to be cooled, wherein the refrigerant amount adjustment section a refrigeration cycle device, comprising: a refrigerant flow rate adjusting unit configured to adjust the flow rate of the refrigerant flowing through the bypass section to a fluid other than the blown air; a refrigerant flow rate adjusting unit configured to adjust the flow rate of the refrigerant flowing through the bypass section to a fluid other than the blown air; [Third Aspect] The refrigeration cycle apparatus according to the first or second aspect, wherein the first heating section includes a first heating heat exchanger (22) that causes the refrigerant discharged from the compressor to radiate heat to the blown air, the second heating section includes a second heating heat exchanger (14) that causes the refrigerant that has passed through the first heating section to radiate heat to the blown air, and the second heating heat exchanger is disposed upstream of the first heating heat exchanger in an air passage for the blown air so that the blown air that has passed through the second heating heat exchanger can flow into the first heating heat exchanger.[Fourth Aspect] The refrigeration cycle apparatus according to the third aspect, wherein the evaporation section includes a cooling heat exchanger (17) that cools the blown air by latent heat of vaporization of the refrigerant after being depressurized in the depressurization section, and the second heating heat exchanger is disposed downstream of the cooling heat exchanger in the ventilation path of the blown air so that at least a portion of the blown air that has passed through the cooling heat exchanger can flow in. [Fifth Aspect] The refrigeration cycle apparatus according to the second to fourth aspects, further including an internal heat exchanger (IHX) that exchanges heat between the refrigerant that has passed through the radiator and the refrigerant that has passed through the evaporation section. [Sixth Aspect] The refrigeration cycle apparatus according to the fourth aspect, wherein the second heating heat exchanger is disposed in the ventilation path of the blown air so that all of the blown air that has passed through the cooling heat exchanger passes through the ventilation path, and the ventilation path of the blown air includes a bypass passage portion (50b) that causes the blown air that has passed through the second heating heat exchanger to bypass the first heating heat exchanger, and is provided with an air volume adjustment portion (54) that adjusts the air volume ratio between the blown air that passes through the first heating heat exchanger and the blown air that passes through the bypass passage portion. [Seventh Aspect] The refrigeration cycle apparatus according to the third or fourth aspect, wherein when a fluid that exchanges heat with the blown air in the first heating heat exchanger is defined as a first fluid and a fluid that exchanges heat with the blown air in the second heating heat exchanger is defined as a second fluid, the second heating heat exchanger has a flow path for the second fluid configured such that a direction of the second fluid flowing through a portion of the second heating heat exchanger facing the first heating heat exchanger is opposite to a direction of the first fluid flowing through a portion of the first heating heat exchanger facing the second heating heat exchanger. [Eighth Aspect] The refrigeration cycle apparatus according to the fourth aspect further includes a control unit (60) that controls the refrigerant amount adjustment unit, wherein when an operating state is reached in which the volume of the blown air passing through the first heating heat exchanger is minimized and the volume of the blown air bypassing the first heating heat exchanger is maximized, the control unit controls the refrigerant amount adjustment unit so that heating of the blown air by the second heating unit is no longer necessary and the refrigerant that has passed through the first heating unit passes through the bypass unit.[Ninth Aspect] The refrigeration cycle apparatus according to the fourth aspect, further comprising a control unit (60) that controls the refrigerant amount adjustment unit, wherein the control unit controls the refrigerant amount adjustment unit based on a temperature of the blown air after passing through the cooling heat exchanger or a temperature of the cooling heat exchanger.

Claims

1. A refrigeration cycle device applicable to an air conditioner (1), comprising: a compressor (11) that compresses and discharges a refrigerant; a first heating section (12, 20, 21, 22, 24) that uses the refrigerant discharged from the compressor as a heat source to heat the blown air to be blown to a space to be air-conditioned; a second heating section (14) that uses the refrigerant after passing through the first heating section as a heat source to heat the blown air; a bypass section (13) that causes the refrigerant after passing through the first heating section to bypass the second heating section; a refrigerant amount adjustment section (FR) that adjusts the flow rate ratio of the refrigerant passing through the second heating section and the refrigerant passing through the bypass section; decompression sections (16a, 16b) that decompress the refrigerant after passing through the second heating section; and an evaporation section (17, 18) that evaporates the refrigerant after being decompressed by the decompression section by heat exchange with a fluid to be cooled, wherein the refrigerant amount adjustment section a refrigeration cycle device in which, when heating of the blown air by the second heating unit is required, the flow rate ratio is adjusted so that the refrigerant after passing through the first heating unit passes through the second heating unit, and, when heating of the blown air by the second heating unit is not required, the flow rate ratio is adjusted so that at least a portion of the refrigerant after passing through the first heating unit passes through the bypass unit.

2. The refrigeration cycle device according to claim 1, further comprising a radiator (SC) for radiating heat from the refrigerant flowing through the bypass portion to a fluid other than the blown air.

3. A refrigeration cycle device as described in claim 1 or 2, wherein the first heating section includes a first heating heat exchanger (22) that causes the refrigerant discharged from the compressor to radiate heat to the blown air, the second heating section includes a second heating heat exchanger (14) that causes the refrigerant after passing through the first heating section to radiate heat to the blown air, and the second heating heat exchanger is arranged upstream of the first heating heat exchanger in the ventilation path of the blown air so that the blown air that has passed through the second heating heat exchanger can flow into the first heating heat exchanger.

4. The refrigeration cycle device of claim 3, wherein the evaporation section includes a cooling heat exchanger (17) that cools the blown air using the latent heat of vaporization of the refrigerant after it has been depressurized in the depressurization section, and the second heating heat exchanger is arranged downstream of the cooling heat exchanger in the ventilation path for the blown air so that at least a portion of the blown air that has passed through the cooling heat exchanger can flow in.

5. A refrigeration cycle device according to claim 2, further comprising an internal heat exchanger (IHX) for exchanging heat between the refrigerant that has passed through the radiator and the refrigerant that has passed through the evaporation section.

6. A refrigeration cycle device as described in claim 4, wherein the second heating heat exchanger is arranged in the ventilation path of the blown air so that the entire amount of the blown air that has passed through the cooling heat exchanger passes through it, and the ventilation path of the blown air includes a bypass passage section (50b) that causes the blown air after passing through the second heating heat exchanger to flow around the first heating heat exchanger, and is provided with an air volume adjustment section (54) that adjusts the air volume ratio between the blown air that passes through the first heating heat exchanger and the blown air that passes through the bypass passage section.

7. A refrigeration cycle device as described in claim 3, wherein when the fluid that exchanges heat with the blown air in the first heating heat exchanger is defined as a first fluid and the fluid that exchanges heat with the blown air in the second heating heat exchanger is defined as a second fluid, the second heating heat exchanger has a flow path for the second fluid configured so that the direction of the second fluid flowing through a portion of the second heating heat exchanger facing the first heating heat exchanger is opposite to the direction of the first fluid flowing through a portion of the first heating heat exchanger facing the second heating heat exchanger.

8. A refrigeration cycle device as described in claim 4, further comprising a control unit (60) for controlling the refrigerant amount adjustment unit, wherein when an operating state is reached in which the volume of the blown air passing through the first heating heat exchanger is minimized and the volume of the blown air bypassing the first heating heat exchanger is maximized, the control unit controls the refrigerant amount adjustment unit so that heating of the blown air by the second heating unit is no longer necessary and the refrigerant after passing through the first heating unit passes through the bypass unit.

9. A refrigeration cycle device as described in claim 4, further comprising a control unit (60) that controls the refrigerant amount adjustment unit, wherein the control unit controls the refrigerant amount adjustment unit based on the temperature of the blown air after passing through the cooling heat exchanger or the temperature of the cooling heat exchanger.

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