JP2012245856A - Cooling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system for a heating source, which can reduce power consumption of a compressor, while securing the cooling and heating abilities and the ability for cooling the heating source.SOLUTION: The cooling system 1 for cooling an HV device 31 includes: a compressor 12; a heat exchanger 14; an expansion valve 16; and a heat exchanger 18. The cooling system 1 also includes a four-way valve 13 which switches a flow of a refrigerant during air-conditioning operation. The cooling system 1 further includes: a first passage and a second passage as paths of the refrigerant, which are connected in parallel between the heat exchanger 14 and the expansion valve 16; a cooling part 30 provided in the second passage to cool the HV device 31; a refrigerant passage 41; and refrigerant passages 43 and 45. The refrigerant passage 41 provides fluid communication between a refrigerant path between the compressor 12 and the heat exchanger 14, and the second passage on a side closer to the heat exchanger 14 than the cooling part 30. The refrigerant passages 43 and 45 provide fluid communication between a refrigerant path between the expansion valve 16 and the heat exchanger 18, and the second passage on a side closer to the expansion valve 16 than the cooling part 30.

Description

  The present invention relates to a cooling device, and more particularly to a cooling device that cools a heat generation source using a vapor compression refrigeration cycle.

  In recent years, attention has been focused on hybrid vehicles, fuel cell vehicles, electric vehicles, and the like that travel with the driving force of a motor as one of the environmental countermeasures. In such a vehicle, electric devices such as a motor, a generator, an inverter, a converter, and a battery generate heat when power is transferred. Therefore, it is necessary to cool these electric devices. In view of this, a technique for cooling a heating element using a vapor compression refrigeration cycle used as a vehicle air conditioner has been proposed.

  For example, in Japanese Patent Laid-Open No. 9-290622 (Patent Document 1), waste heat from a heat generating component mounted on a vehicle is collected and absorbed into a refrigerant for gas injection, thereby increasing the heating capacity at a low outside temperature. A technique for effectively improving power consumption while suppressing an increase in power consumption is disclosed. Japanese Patent Laid-Open No. 11-223406 (Patent Document 2) discloses a configuration in which waste heat of a heating element such as a power transistor is absorbed by a refrigerant of a heat pump cycle. JP 2007-69733 A (Patent Document 3) includes a heat exchanger that exchanges heat with air for air conditioning, a heat exchanger that exchanges heat with a heating element, in a refrigerant passage from an expansion valve to a compressor, Are arranged in parallel, and a system for cooling a heating element using a refrigerant for an air conditioner is disclosed.

  Japanese Patent Laid-Open No. 2005-90862 (Patent Document 4) is provided with a heating element cooling means for cooling a heating element in a bypass passage that bypasses a decompressor, an evaporator and a compressor of a refrigeration cycle for air conditioning. A cooling system is disclosed. In Japanese Patent Laid-Open No. 2001-309506 (Patent Document 5), the refrigerant of the refrigeration cycle device for vehicle air conditioning is recirculated to the cooling member of the inverter circuit unit that drives and controls the vehicle travel motor, and cooling of the air-conditioning air flow is unnecessary Discloses a cooling system that suppresses cooling of an air-conditioned air flow by an evaporator of a vehicle air-conditioning refrigeration cycle apparatus.

JP-A-9-290622 JP-A-11-223406 JP 2007-69733 A JP-A-2005-90862 JP 2001-309506 A

  When heating operation is performed using a vapor compression refrigeration cycle when the outside air temperature is extremely low, the pressure of the refrigerant decompressed by the decompressor decreases, the compressor compression ratio increases, and the compression efficiency decreases, resulting in consumption. Power increases. Moreover, the discharge gas temperature of a compressor also becomes high and there exists a problem which an internal wire insulation material and lubricating oil deteriorate and have a bad influence. In order not to deteriorate the power consumption of the compressor, there is a problem that the heating capacity must be sacrificed.

  In the technique described in Patent Document 1, the compression power of the compressor is suppressed by evaporating the intermediate pressure refrigerant with the waste heat of the heat-generating component and gas-injecting it into the compressor. However, since the refrigerant corresponding to the gas injection is directly introduced into the compressor, the amount of the refrigerant supplied to the indoor heat exchanger during the cooling operation is reduced, and the cooling capacity is lowered. If the refrigerant flow rate is increased, the cooling capacity can be ensured, but the power consumption of the compressor increases accordingly.

  The present invention has been made in view of the above problems, and a main object thereof is to provide a cooling device for a heat source that can reduce the power consumption of the compressor while ensuring the air conditioning capability and the cooling capability of the heat source. That is.

  A cooling device according to the present invention is a cooling device that cools a heat generation source, a compressor for circulating a refrigerant, a first heat exchanger that exchanges heat between the refrigerant and outside air, and a pressure reduction of the refrigerant. A decompressor, and a second heat exchanger that exchanges heat between the refrigerant and the air for air conditioning. The cooling device also includes a four-way valve that switches between a refrigerant flow from the compressor to the first heat exchanger and a refrigerant flow from the compressor to the second heat exchanger. The cooling device is also provided on the first passage and the second passage, which are refrigerant paths connected in parallel between the first heat exchanger and the decompressor, and the second passage, and uses the refrigerant to generate a heat source. A cooling section for cooling the first passage, a first series passage, and a second communication passage. The first series passage communicates the refrigerant path between the compressor and the first heat exchanger and the second passage closer to the first heat exchanger with respect to the cooling unit. The second communication path communicates the refrigerant path between the decompressor and the second heat exchanger and the second path on the side close to the decompressor with respect to the cooling unit.

  Preferably, the cooling device includes a third heat exchanger that is provided in a refrigerant path that circulates between the cooling unit and the decompressor and exchanges heat between the refrigerant and the outside air.

  Preferably, the cooling device includes a second pressure reducer provided in a refrigerant path flowing between the first heat exchanger and the cooling unit.

  Preferably, the cooling device includes a gas-liquid separator disposed in the second passage on the side close to the first heat exchanger with respect to the cooling unit. One end of the first series passage may be disposed in the gas phase of the gas-liquid separator.

  The cooling device preferably includes a booster that increases the pressure of the refrigerant flowing from the cooling unit toward the first series passage.

  Preferably, in the cooling device, when the four-way valve is set so that the refrigerant flows from the compressor toward the second heat exchanger, the refrigerant path is switched so that the refrigerant does not flow through the first heat exchanger.

  According to the cooling device of the present invention, the power consumption of the compressor can be reduced while ensuring the cooling / heating capability and the cooling capability of the heat source.

2 is a schematic diagram illustrating a configuration of a cooling device according to Embodiment 1. FIG. FIG. 3 is a Mollier diagram showing the state of the refrigerant during the cooling operation of the vapor compression refrigeration cycle of the first embodiment. It is a schematic diagram which shows the cooling device of the state which switched the four-way valve. FIG. 3 is a Mollier diagram showing the state of the refrigerant during the heating operation of the vapor compression refrigeration cycle of the first embodiment. 6 is a schematic diagram illustrating a configuration of a cooling device according to Embodiment 2. FIG. 6 is a Mollier diagram showing the state of the refrigerant during cooling operation of the vapor compression refrigeration cycle of Embodiment 2. FIG. It is a schematic diagram which shows the cooling device of Embodiment 2 in the state which switched the four-way valve. 6 is a Mollier diagram showing the state of refrigerant during heating operation of the vapor compression refrigeration cycle of Embodiment 2. FIG. 6 is a schematic diagram illustrating a configuration of a cooling device according to Embodiment 3. FIG. 6 is a Mollier diagram showing the state of refrigerant during heating operation of the vapor compression refrigeration cycle of Embodiment 3. FIG. FIG. 6 is a schematic diagram illustrating a configuration of a cooling device according to a fourth embodiment. It is a schematic diagram which shows the cooling device of Embodiment 4 in the state which switched the four-way valve. FIG. 10 is a Mollier diagram showing the state of refrigerant during heating operation of the vapor compression refrigeration cycle of the fourth embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a schematic diagram illustrating a configuration of a cooling device 1 according to the first embodiment. As shown in FIG. 1, the cooling device 1 includes a vapor compression refrigeration cycle 10. The vapor compression refrigeration cycle 10 is mounted on a vehicle, for example, for cooling and heating the interior of the vehicle. The cooling using the vapor compression refrigeration cycle 10 is selected, for example, when the switch for performing the cooling is turned on or the automatic control mode for automatically adjusting the temperature of the vehicle interior to the set temperature is selected. This is performed when the temperature in the passenger compartment is higher than the set temperature. Heating using the vapor compression refrigeration cycle 10 is performed, for example, when a switch for heating is turned on, or when the automatic control mode is selected and the temperature in the passenger compartment is lower than the set temperature. To be done.

  The vapor compression refrigeration cycle 10 includes a compressor 12, a heat exchanger 14 as a first heat exchanger, an expansion valve 16 as an example of a decompressor, a heat exchanger 18 as a second heat exchanger, including. The vapor compression refrigeration cycle 10 also includes a four-way valve 13. The four-way valve 13 is disposed so as to be able to switch between a refrigerant flow from the compressor 12 toward the heat exchanger 14 and a refrigerant flow from the compressor 12 toward the heat exchanger 18.

  The compressor 12 operates using a motor or engine mounted on the vehicle as a power source, and compresses the refrigerant gas in an adiabatic manner to form an overheated refrigerant gas. The compressor 12 sucks and compresses the gas-phase refrigerant that circulates during the operation of the vapor compression refrigeration cycle 10 and discharges the high-temperature and high-pressure gas-phase refrigerant. The compressor 12 circulates the refrigerant in the vapor compression refrigeration cycle 10 by discharging the refrigerant.

  The heat exchangers 14 and 18 include tubes through which the refrigerant flows, and fins for exchanging heat between the refrigerant flowing through the tubes and the air around the heat exchangers 14 and 18. The heat exchangers 14 and 18 perform heat exchange between the refrigerant and the air flow supplied by natural ventilation generated by traveling of the vehicle or the air flow supplied by a fan.

  The expansion valve 16 is expanded by injecting a high-pressure liquid-phase refrigerant from a small hole, and changes into a low-temperature / low-pressure mist refrigerant. The expansion valve 16 depressurizes the condensed refrigerant liquid to obtain wet vapor in a gas-liquid mixed state. Note that the decompressor for decompressing the refrigerant liquid is not limited to the expansion valve 16 that is squeezed and expanded, and may be a capillary tube.

  The vapor compression refrigeration cycle 10 also includes refrigerant passages 21 to 26. The refrigerant passage 21 communicates the compressor 12 and the four-way valve 13. The refrigerant flows from the compressor 12 toward the four-way valve 13 via the refrigerant passage 21. The refrigerant passage 22 communicates the four-way valve 13 and the heat exchanger 14. The refrigerant flows from one of the four-way valve 13 and the heat exchanger 14 toward the other via the refrigerant passage 22. The refrigerant passage 23 communicates the heat exchanger 14 and the expansion valve 16. The refrigerant flows from one of the heat exchanger 14 and the expansion valve 16 toward the other via the refrigerant passage 23.

  The refrigerant passage 24 communicates the expansion valve 16 and the heat exchanger 18. The refrigerant flows from one of the expansion valve 16 and the heat exchanger 18 toward the other via the refrigerant passage 24. The refrigerant passage 25 communicates the heat exchanger 18 and the four-way valve 13. The refrigerant flows from one of the heat exchanger 18 and the four-way valve 13 toward the other via the refrigerant passage 25. The refrigerant passage 26 communicates the four-way valve 13 and the compressor 12. The refrigerant flows from the four-way valve 13 toward the compressor 12 via the refrigerant passage 26.

  The vapor compression refrigeration cycle 10 includes a compressor 12, a heat exchanger 14, an expansion valve 16, and a heat exchanger 18 connected by refrigerant passages 21 to 26. In addition, as a refrigerant of the vapor compression refrigeration cycle 10, for example, carbon dioxide, hydrocarbon such as propane and isobutane, ammonia, water, or the like can be used.

  A refrigerant passage 23 a serving as a first passage and a second passage are connected in parallel to the refrigerant passage that flows between the heat exchanger 14 and the expansion valve 16. The refrigerant passage 23 a forms a part of the refrigerant passage 23 that forms a path of the refrigerant that flows between the heat exchanger 14 and the expansion valve 16. A cooling unit 30 is provided on the second passage. The cooling unit 30 is provided on a refrigerant path that circulates between the heat exchanger 14 and the expansion valve 16. The cooling unit 30 includes an HV (Hybrid Vehicle) device 31 that is an electric device mounted on the vehicle, and a cooling passage 32 that is a pipe through which a refrigerant flows. The HV device 31 is an example of a heat source. The refrigerant path between the heat exchanger 14 and the expansion valve 16 branches, and a part of the refrigerant flows to the cooling unit 30.

  Refrigerant passages 33, 34, 35, and 36 are provided as routes for circulating the refrigerant to the cooling passage 32. One end of the cooling passage 32 is connected to the refrigerant passage 34. The other end of the cooling passage 32 is connected to the refrigerant passage 35. The refrigerant passage 33 and the refrigerant passage 34 communicate with each other via a three-way valve 42. The refrigerant passage 35 and the refrigerant passage 36 communicate with each other via a three-way valve 46. The refrigerant flows from the refrigerant passage 23 to the cooling passage 32 via one of the refrigerant passages 33 and 34 and the refrigerant passages 35 and 36. The refrigerant after passing through the cooling passage 32 and exchanging heat with the HV device 31 returns to the refrigerant passage 23 via the other of the refrigerant passages 33 and 34 and the refrigerant passages 35 and 36.

  The second passage connected in parallel with the refrigerant passage 23 a includes refrigerant passages 33 and 34 closer to the heat exchanger 14 than the cooling portion 30, a cooling passage 32 included in the cooling portion 30, and the cooling portion 30. Includes refrigerant passages 35 and 36 on the side close to the expansion valve 16. The refrigerant flows between the refrigerant passage 23 and the cooling unit 30 via the refrigerant passages 33 and 34. The refrigerant flows between the cooling unit 30 and the refrigerant passage 23 via the refrigerant passages 35 and 36.

  The refrigerant flowing between the heat exchanger 14 and the expansion valve 16 flows through the cooling passage 32. When the refrigerant flows through the cooling passage 32, it takes heat from the HV equipment 31 and cools the HV equipment 31. The cooling unit 30 is provided so as to have a structure capable of exchanging heat between the HV device 31 and the refrigerant through the cooling passage 32. In the present embodiment, the cooling unit 30 includes, for example, a cooling passage 32 formed so that the outer peripheral surface of the cooling passage 32 directly contacts the housing of the HV device 31. The cooling passage 32 has a portion adjacent to the housing of the HV device 31. In this part, heat exchange can be performed between the refrigerant flowing through the cooling passage 32 and the HV equipment 31.

  The HV equipment 31 is directly connected to the outer peripheral surface of the cooling passage 32 that forms part of the refrigerant path that flows between the heat exchanger 14 and the expansion valve 16 of the vapor compression refrigeration cycle 10 and is cooled. . Since the HV device 31 is disposed outside the cooling passage 32, the HV device 31 does not interfere with the flow of the refrigerant flowing through the cooling passage 32. Therefore, since the pressure loss of the vapor compression refrigeration cycle 10 does not increase, the HV equipment 31 can be cooled without increasing the power of the compressor 12.

  Alternatively, the cooling unit 30 may include any known heat pipe disposed between the HV device 31 and the cooling passage 32. In this case, the HV device 31 is connected to the outer peripheral surface of the cooling passage 32 via a heat pipe, and is cooled by transferring heat from the HV device 31 to the cooling passage 32 via the heat pipe. Since the heat transfer efficiency between the cooling passage 32 and the HV equipment 31 can be increased by using the HV equipment 31 as the heat pipe heating section and the cooling passage 32 as the heat pipe cooling section, the cooling efficiency of the HV equipment 31 can be increased. It can be improved. For example, a wick-type heat pipe can be used.

  Since heat can be reliably transferred from the HV device 31 to the cooling passage 32 by the heat pipe, there may be a distance between the HV device 31 and the cooling passage 32, and the cooling passage 32 is brought into contact with the HV device 31. It is not necessary to arrange the cooling passage 32 in a complicated manner. As a result, the degree of freedom of arrangement of the HV device 31 can be improved.

  As a path through which the refrigerant flows between the heat exchanger 14 and the expansion valve 16, the refrigerant paths 33 to 36 and the cooling path 32 that are paths of the refrigerant that passes through the cooling unit 30, and the path of the refrigerant that does not pass through the cooling unit 30 The refrigerant passage 23a is provided in parallel. The cooling system of the HV device 31 including the refrigerant passages 33 to 36 and the cooling passage 32 is connected in parallel with the refrigerant passage 23a. A refrigerant path that flows between the heat exchanger 14 and the expansion valve 16 without passing through the cooling unit 30 and a refrigerant path that flows through the cooling unit 30 are provided in parallel, and only a part of the refrigerant passes through the refrigerant path. By allowing the refrigerant to flow to 33 to 36, only a part of the refrigerant flowing between the heat exchanger 14 and the expansion valve 16 flows to the cooling unit 30.

  An amount of refrigerant necessary for cooling the HV device 31 in the cooling unit 30 is circulated through the refrigerant passages 33 to 36, and all the refrigerant does not flow to the cooling unit 30. Therefore, the HV device 31 is appropriately cooled, and the HV device 31 can be prevented from being overcooled. Moreover, the pressure loss which concerns on the distribution | circulation of the refrigerant | coolant to the cooling system of the HV apparatus 31 containing the refrigerant paths 33-36 and the cooling path 32 can be reduced. Accordingly, it is possible to reduce the power consumption necessary for the operation of the compressor 12 for circulating the refrigerant.

  The HV device 31 includes an electrical device that generates heat when power is transferred. The electrical equipment includes, for example, an inverter for converting DC power into AC power, a motor generator that is a rotating electrical machine, a battery that is a power storage device, a converter that boosts the voltage of the battery, and a DC that steps down the voltage of the battery. Including at least one of DC / DC converters and the like. The battery is a secondary battery such as a lithium ion battery or a nickel metal hydride battery. A capacitor may be used instead of the battery.

  The heat exchanger 18 is disposed inside a duct 90 through which air flows. The heat exchanger 18 exchanges heat between the refrigerant and the air-conditioning air flowing through the duct 90 to adjust the temperature of the air-conditioning air. The duct 90 has a duct inlet 91 that is an inlet through which air-conditioning air flows into the duct 90, and a duct outlet 92 that is an outlet through which air-conditioning air flows out from the duct 90. A fan 93 is disposed in the vicinity of the duct inlet 91 inside the duct 90.

  When the fan 93 is driven, air flows in the duct 90. When the fan 93 is in operation, air for air conditioning flows into the duct 90 via the duct inlet 91. The air flowing into the duct 90 may be outside air or air in the vehicle interior. An arrow 95 in FIG. 1 indicates the flow of air-conditioning air that flows through the heat exchanger 18 and exchanges heat with the refrigerant of the vapor compression refrigeration cycle 10. During the cooling operation, the air-conditioning air is cooled in the heat exchanger 18, and the refrigerant is heated by receiving heat transfer from the air-conditioning air. During the heating operation, the air-conditioning air is heated in the heat exchanger 18, and the refrigerant is cooled by transferring heat to the air-conditioning air. An arrow 96 indicates the flow of air-conditioning air that is temperature-adjusted by the heat exchanger 18 and flows out of the duct 90 via the duct outlet 92.

  During the cooling operation, the refrigerant flows through the vapor compression refrigeration cycle 10 so as to pass through the points A, B, C, D, and E shown in FIG. 1 in order, and the compressor 12, the heat exchanger 14, and the expansion The refrigerant circulates between the valve 16 and the heat exchanger 18. The refrigerant circulates in the vapor compression refrigeration cycle 10 through a refrigerant circulation passage in which the compressor 12, the heat exchanger 14, the expansion valve 16, and the heat exchanger 18 are sequentially connected by refrigerant passages 21 to 26. .

  FIG. 2 is a Mollier diagram showing the state of the refrigerant during the cooling operation of the vapor compression refrigeration cycle 10 of the first embodiment. The horizontal axis in FIG. 2 represents the specific enthalpy (unit: kJ / kg) of the refrigerant, and the vertical axis represents the absolute pressure (unit: MPa) of the refrigerant. The curves in the figure are the saturated vapor line and saturated liquid line of the refrigerant. In FIG. 2, the refrigerant flows into the refrigerant passage 23 from the compressor 12 via the heat exchanger 14, cools the HV equipment 31, returns to the refrigerant passage 23, and compresses via the expansion valve 16 and the heat exchanger 18. Returning to the machine 12, the thermodynamic state of the refrigerant at each point in the vapor compression refrigeration cycle 10 (ie, points A, B, C, D and E) is shown.

  As shown in FIG. 2, the superheated vapor refrigerant (point A) sucked into the compressor 12 is adiabatically compressed along the isentropic line in the compressor 12. As the compressor is compressed, the pressure and temperature of the refrigerant rise and become high-temperature and high-pressure superheated steam with a high degree of superheat (point B), and the refrigerant flows to the heat exchanger 14.

  The high-pressure refrigerant vapor entering the heat exchanger 14 is cooled by exchanging heat with the outside air in the heat exchanger 14. Refrigerant changes from superheated steam to dry steam with constant pressure, releases latent heat of condensation, gradually liquefies and becomes wet steam in a gas-liquid mixed state, becomes saturated liquid when all of the refrigerant condenses, and further sensible heat To become supercooled liquid (point C). The heat exchanger 14 causes the superheated refrigerant gas compressed in the compressor 12 to dissipate heat to the external medium in an isobaric manner to obtain a refrigerant liquid. The gas-phase refrigerant discharged from the compressor 12 is condensed (liquefied) by releasing heat to the surroundings in the heat exchanger 14 and being cooled. By the heat exchange in the heat exchanger 14, the temperature of the refrigerant decreases and the refrigerant liquefies.

  The high-pressure liquid-phase refrigerant liquefied by the heat exchanger 14 flows to the cooling unit 30 via the refrigerant passage 33, the three-way valve 42, and the refrigerant passage 34 in order, and cools the HV equipment 31. The degree of supercooling of the refrigerant is reduced by heat exchange with the HV device 31. That is, the temperature of the refrigerant in the supercooled liquid state rises upon receiving sensible heat from the HV device 31, approaches the saturation temperature of the liquid refrigerant, and is heated to a temperature slightly below the saturation temperature (point D). Thereafter, the refrigerant returns to the refrigerant passage 23 via the refrigerant passage 35, the three-way valve 46 and the refrigerant passage 36 in order, and flows into the expansion valve 16 via the refrigerant passage 23. By passing through the expansion valve 16, the refrigerant in the supercooled liquid state is squeezed and expanded, the specific enthalpy of the refrigerant does not change, the temperature and pressure are reduced, and the low temperature and low pressure gas-liquid mixed vapor is obtained ( E point).

  The wet steam refrigerant that has flowed out of the expansion valve 16 flows into the heat exchanger 18 via the refrigerant passage 24. A wet steam refrigerant flows into the tube of the heat exchanger 18. When the refrigerant flows through the tube of the heat exchanger 18, it absorbs the heat of the air-conditioning air as a latent heat of evaporation via the fins, and evaporates at a constant pressure. When all the refrigerants are dry and become saturated vapor, the temperature of the refrigerant vapor further rises due to sensible heat and becomes superheated vapor (point A). The refrigerant absorbs heat from the surroundings in the heat exchanger 18 and is heated. The vaporized refrigerant flows to the four-way valve 13 via the refrigerant passage 25 and further sucked into the compressor 12 via the refrigerant passage 26. The compressor 12 compresses the refrigerant flowing from the heat exchanger 18. In accordance with such a cycle, the refrigerant continuously repeats the compression, condensation, throttle expansion, and evaporation state changes.

  In the above description of the vapor compression refrigeration cycle, the theoretical refrigeration cycle is described. However, in the actual vapor compression refrigeration cycle 10, it is necessary to consider the loss in the compressor 12, the pressure loss of the refrigerant, and the heat loss. Of course there is.

  During the cooling operation, the heat exchanger 18 absorbs the heat of ambient air introduced so as to come into contact with the heat exchanger 18 by vaporizing the mist refrigerant flowing through the heat exchanger 18. The heat exchanger 18 is used for air conditioning in which the low-temperature and low-pressure refrigerant that has been expanded by the expansion valve 16 and reduced in pressure is used to circulate heat of vaporization when the refrigerant's wet vapor evaporates into refrigerant gas into the vehicle interior. Absorbs from the air and cools the interior of the vehicle. Air-conditioning air whose temperature has been reduced by heat being absorbed by the heat exchanger 18 flows into the vehicle compartment, thereby cooling the vehicle compartment.

  During the operation of the vapor compression refrigeration cycle 10, the refrigerant absorbs heat of vaporization from the air-conditioning air in the heat exchanger 18 and cools the passenger compartment. In addition, the high-pressure liquid refrigerant output from the heat exchanger 14 flows to the cooling unit 30 and heat-exchanges with the HV device 31 to cool the HV device 31. The cooling device 1 cools the HV equipment 31 that is a heat source mounted on the vehicle by using a vapor compression refrigeration cycle 10 for air conditioning in the vehicle interior. Note that the temperature required for cooling the HV device 31 is desirably at least lower than the upper limit value of the target temperature range as the temperature range of the HV device 31.

  Returning to FIG. 1, the cooling device 1 includes a flow rate adjustment valve 51. The flow rate adjusting valve 51 is disposed in a refrigerant passage 23 a that forms a part of the refrigerant passage 23 between the heat exchanger 14 and the expansion valve 16. The flow rate adjusting valve 51 changes the valve opening, and increases or decreases the pressure loss of the refrigerant flowing through the refrigerant passage 23a, thereby flowing through the refrigerant flow rate through the refrigerant passage 23a, the refrigerant passages 33 to 36, and the cooling passage 32. The flow rate of the refrigerant is arbitrarily adjusted.

  For example, when the flow rate adjustment valve 51 is fully closed and the valve opening degree is set to 0%, the entire amount of refrigerant flowing between the heat exchanger 14 and the expansion valve 16 flows into the refrigerant passages 33 to 36 and the cooling passage 32. If the valve opening degree of the flow rate adjusting valve 51 is increased, the flow rate of the refrigerant flowing between the heat exchanger 14 and the expansion valve 16 through the refrigerant passage 23a increases, and the refrigerant passages 33 to 36 and the cooling passages are cooled. The flow rate of the refrigerant that flows through the passage 32 and cools the HV equipment 31 is reduced. If the valve opening degree of the flow rate adjusting valve 51 is reduced, the flow rate flowing through the refrigerant passage 23a among the refrigerant flowing between the heat exchanger 14 and the expansion valve 16 is reduced, and the refrigerant passages 33 to 36 and the cooling passages are cooled. The flow rate of the refrigerant that flows through the passage 32 and cools the HV equipment 31 increases.

  When the valve opening degree of the flow rate adjusting valve 51 is increased, the flow rate of the refrigerant that cools the HV device 31 is decreased, and the cooling capacity of the HV device 31 is decreased. When the valve opening degree of the flow rate adjusting valve 51 is reduced, the flow rate of the refrigerant that cools the HV device 31 is increased, and the cooling capacity of the HV device 31 is improved. Since the amount of the refrigerant flowing through the cooling unit 30 can be optimally adjusted using the flow rate adjusting valve 51, it is possible to reliably prevent overcooling of the HV equipment 31, and in addition, the refrigerant passages 33 to 36 and the cooling passage The pressure loss associated with the circulation of the 32 refrigerant and the power consumption of the compressor 12 for circulating the refrigerant can be reliably reduced.

  The cooling device 1 includes a refrigerant passage 41 as a first series passage. One end of the refrigerant passage 41 is connected to the refrigerant passage 22 which is a refrigerant path between the compressor 12 and the heat exchanger 14. Since the refrigerant passage 41 is connected, the refrigerant passage 22 is connected to the refrigerant passage 22a closer to the four-way valve 13 than the connection portion between the refrigerant passage 22 and the refrigerant passage 41, and to the heat exchanger 14 than the connection portion. The refrigerant passage 22b is divided into two adjacent parts. The other end of the refrigerant passage 41 is connected to the three-way valve 42. The refrigerant passage 41 is connected to the refrigerant passages 33 and 34, which are refrigerant paths closer to the heat exchanger 14 with respect to the cooling unit 30, of the second passage through which the refrigerant flows to the cooling unit 30 via the three-way valve 42. Connected. The refrigerant passage 41 communicates the refrigerant passage 22 with the refrigerant passages 33 and 34.

  An expansion valve 47 is provided in the refrigerant passage 41. Like the expansion valve 16, the expansion valve 47 expands and expands the refrigerant, and reduces the temperature and pressure of the refrigerant without changing the specific enthalpy of the refrigerant. The expansion valve 47 is disposed in the first series passage.

The cooling device 1 includes refrigerant passages 43 and 45 and an expansion valve 44 that constitute a second communication passage.
The refrigerant passage 43 and the refrigerant passage 45 communicate with each other via an expansion valve 44. The expansion valve 44 as another decompressor different from the decompressor (expansion valve 16), like the expansion valve 16, expands and expands the refrigerant, and adjusts the temperature and pressure of the refrigerant without changing the specific enthalpy of the refrigerant. Reduce. The expansion valve 44 is disposed in the second communication path.

  One end of the refrigerant passage 43 is connected to the expansion valve 44, and the other end is connected to the refrigerant passage 24 that is a refrigerant path between the expansion valve 16 and the heat exchanger 18. Since the refrigerant passage 43 is connected, the refrigerant passage 24 is connected to the refrigerant passage 24a closer to the expansion valve 16 than the connection portion between the refrigerant passage 24 and the refrigerant passage 43, and to the heat exchanger 18 than the connection portion. The refrigerant passage 24b is divided into two, which are adjacent to each other.

  One end of the refrigerant passage 45 is connected to the expansion valve 44, and the other end is connected to the three-way valve 46. The refrigerant passage 45 is connected to the refrigerant passages 35 and 36, which are refrigerant paths close to the expansion valve 16 with respect to the cooling unit 30, of the second passage through which the refrigerant flows to the cooling unit 30 via the three-way valve 46. It is connected. The second communication passage including the refrigerant passages 43 and 45 and the expansion valve 44 communicates the refrigerant passage 24 and the refrigerant passages 35 and 36.

  FIG. 3 is a schematic diagram showing the cooling device 1 in a state where the four-way valve 13 is switched. Comparing FIG. 1 and FIG. 3, when the four-way valve 13 rotates by 90 °, the path from which the refrigerant flowing into the four-way valve 13 from the outlet of the compressor 12 exits the four-way valve 13 is switched. During the cooling operation shown in FIG. 1, the refrigerant compressed in the compressor 12 flows from the compressor 12 toward the heat exchanger 14. On the other hand, during the heating operation shown in FIG. 3, the refrigerant compressed in the compressor 12 flows from the compressor 12 toward the heat exchanger 18.

  During the cooling operation shown in FIG. 1, the three-way valve 42 as the first valve is set to open and close so that the refrigerant passage 33 and the refrigerant passage 34 communicate with each other and the refrigerant passage 41 and the refrigerant passages 33 and 34 do not communicate with each other. Is done. The three-way valve 46 as the second valve is set to open and close so that the refrigerant passage 35 and the refrigerant passage 36 communicate with each other, and the refrigerant passage 45 and the refrigerant passages 35 and 36 do not communicate with each other. During the cooling operation, the three-way valve 42 allows the refrigerant to flow between the refrigerant passages 33 and 34 included in the second passage, which is the passage of the refrigerant flowing to the cooling unit 30, and the refrigerant passage 41 as the first series passage. Ban. During the cooling operation, the three-way valve 46 prohibits the circulation of the refrigerant between the refrigerant passages 35 and 36 included in the second passage and the refrigerant passages 43 and 45 included in the second communication passage.

  On the other hand, during the heating operation shown in FIG. 3, the three-way valve 42 is switched between open and closed so that the refrigerant passage 34 and the refrigerant passage 41 communicate with each other and the refrigerant passage 33 and the refrigerant passages 34 and 41 do not communicate with each other. The three-way valve 46 can be switched between open and closed so that the refrigerant passage 35 and the refrigerant passage 45 communicate with each other and the refrigerant passage 36 and the refrigerant passages 35 and 45 do not communicate with each other. During the heating operation, the three-way valve 42 allows the refrigerant to flow between the refrigerant passage 34 and the refrigerant passage 41. During the heating operation, the three-way valve 46 allows the refrigerant to flow between the refrigerant passage 35 and the refrigerant passages 43 and 45.

  Therefore, during the heating operation, the refrigerant adiabatically compressed by the compressor 12 and heat-exchanged with the air-conditioning air by the heat exchanger 18 branches from the refrigerant passage 24b into the refrigerant passage 24a and the refrigerant passage 43 and flows in. The refrigerant that has flowed into the refrigerant passage 24 a passes through the expansion valve 16, flows through the refrigerant passage 23, and reaches the refrigerant passage 22 b through the heat exchanger 14. The refrigerant that has flowed into the refrigerant passage 43 passes through the expansion valve 44 and flows through the refrigerant passages 45 and 35, passes through the refrigerant passage 34 via the cooling unit 30, and reaches the refrigerant passage 41 from the three-way valve 42. The refrigerant flowing through the refrigerant passage 22b and the refrigerant flowing through the refrigerant passage 41 merge at the connection portion of the refrigerant passages 22 and 41 and flow to the refrigerant passage 22a.

  That is, during the heating operation, the refrigerant flows through the vapor compression refrigeration cycle 10 so as to sequentially pass through the points A, B, E, D, C, and J shown in FIG. The refrigerant circulates through the exchanger 18, the expansion valve 44, and the cooling unit 30, and flows through the points A, B, E, F, and G shown in FIG. 12, the refrigerant circulates in the heat exchanger 18, the expansion valve 16, and the heat exchanger 14. The refrigerant includes a refrigerant circulation passage in which the compressor 12, the heat exchanger 18, the expansion valve 44, and the cooling unit 30 are sequentially connected, the compressor 12, the heat exchanger 18, the expansion valve 16, and the heat exchanger 14. It circulates through the vapor compression refrigeration cycle 10 through the sequentially connected refrigerant circulation passages.

  FIG. 4 is a Mollier diagram showing the state of the refrigerant during the heating operation of the vapor compression refrigeration cycle 10 of the first embodiment. The horizontal axis in FIG. 4 indicates the specific enthalpy (unit: kJ / kg) of the refrigerant, and the vertical axis indicates the absolute pressure (unit: MPa) of the refrigerant. The curves in the figure are the saturated vapor line and saturated liquid line of the refrigerant. In FIG. 4, each point in the vapor compression refrigeration cycle 10 (that is, A, B) that flows from the compressor 12 through the heat exchanger 18, the expansion valve 44, and the cooling unit 30 in order and returns to the compressor 12. , E, D, C and J points) shows the thermodynamic state of the refrigerant. In FIG. 4, each point in the vapor compression refrigeration cycle 10 (that is, A) flows from the compressor 12 through the heat exchanger 18, the expansion valve 16, and the heat exchanger 14 in order and returns to the compressor 12. , B, E, F and G points) shows the thermodynamic state of the cooling.

  As shown in FIG. 4, the superheated vapor refrigerant (point A) sucked into the compressor 12 is adiabatically compressed in the compressor 12 along the isentropic entropy line. As the compressor is compressed, the pressure and temperature of the refrigerant rise and become high-temperature and high-pressure superheated steam with a high degree of superheat (point B), and the refrigerant flows to the heat exchanger 18.

  The high-pressure refrigerant vapor that has entered the heat exchanger 18 is cooled in the heat exchanger 18, and changes from superheated steam to dry saturated vapor while maintaining the constant pressure, releases latent heat of condensation, gradually liquefies, and wets in a gas-liquid mixed state. When it becomes steam and all of the refrigerant condenses, it becomes a saturated liquid, further releases sensible heat and becomes a supercooled liquid (point E). The heat exchanger 18 causes the superheated refrigerant gas compressed in the compressor 12 to dissipate heat to the external medium in an isobaric manner to obtain a refrigerant liquid. The gas phase refrigerant discharged from the compressor 12 is condensed (liquefied) by releasing heat to the surroundings in the heat exchanger 18 and being cooled. By the heat exchange in the heat exchanger 18, the temperature of the refrigerant is lowered and the refrigerant is liquefied. The refrigerant dissipates heat to the surroundings in the heat exchanger 18 and is cooled.

  The high-pressure liquid refrigerant liquefied by the heat exchanger 18 branches from the refrigerant passage 24b to the refrigerant passage 24a and the refrigerant passage 43. A part of the liquid-phase refrigerant flowing into the refrigerant passage 24a flows into the expansion valve 16 through the refrigerant passage 24a. In the expansion valve 16, the refrigerant in the supercooled liquid state is squeezed and expanded, the specific enthalpy of the refrigerant does not change, the temperature and pressure decrease, and the mixture becomes wet steam in a low-temperature and low-pressure gas-liquid mixed state (point F). The refrigerant whose temperature has been lowered in the expansion valve 16 flows into the heat exchanger 14 via the refrigerant passage 23. A wet steam refrigerant flows into the tube of the heat exchanger 14. When the refrigerant circulates in the tube, the refrigerant is heated by absorbing the heat of the outside air as latent heat of evaporation via the fins, evaporates while maintaining the equal pressure, and the dryness of the refrigerant increases. When all the refrigerants are dry and become saturated vapor, the refrigerant vapor further rises in temperature due to sensible heat and becomes superheated vapor (point G).

  A part of the liquid-phase refrigerant flowing into the refrigerant passage 43 flows into the expansion valve 44 via the refrigerant passage 43. In the expansion valve 44, the refrigerant in the supercooled liquid state is squeezed and expanded, the specific enthalpy of the refrigerant does not change, the temperature and pressure are reduced, and the gas-liquid mixed wet steam is obtained (point D). The refrigerant whose temperature has been lowered in the expansion valve 44 flows into the cooling passage 32 of the cooling unit 30 via the refrigerant passages 45 and 35 and cools the HV equipment 31. By the heat exchange with the HV equipment 31, the refrigerant is heated and the dryness of the refrigerant increases. By receiving latent heat from the HV device 31 and vaporizing a part of the refrigerant, the ratio of saturated vapor contained in the refrigerant in the wet vapor state increases (point C).

  The wet vapor refrigerant flowing out of the cooling unit 30 and flowing through the refrigerant passage 34 flows into the expansion valve 47 via the refrigerant passage 41. In the expansion valve 47, the refrigerant is throttled and expanded, and the specific enthalpy of the refrigerant does not change, and the temperature and pressure decrease (point J). The pressure of the refrigerant after passing through the expansion valve 47 becomes equal to the pressure of the refrigerant flowing through the cooling valve 30 after passing through the expansion valve 16 and being reduced in pressure. The wet vapor refrigerant flowing through the refrigerant passage 41 after passing through the expansion valve 47 and the superheated vapor refrigerant flowing through the refrigerant passage 22b via the heat exchanger 14 have the same pressure. Therefore, both the refrigerant flowing through the refrigerant passage 41 and the refrigerant flowing through the refrigerant passage 22b flow into the refrigerant passage 22a and are mixed.

  The mixed refrigerant has a pressure equal to the pressure at points J and G shown in FIG. The specific enthalpy of the mixed refrigerant is determined by the specific enthalpy and flow rate ratio of the refrigerant flowing through each of the refrigerant passages 22b and 41. For example, if the flow rates of the refrigerants flowing through the refrigerant passages 22b and 41 are equal, the mixed refrigerant has a specific enthalpy intermediate between the specific enthalpy at the point J and the specific enthalpy at the point G (point A). The refrigerant flowing through the refrigerant passage 22a has the same pressure as the refrigerant flowing through the refrigerant passages 22b and 41, and has a specific enthalpy greater than that of the refrigerant flowing through the refrigerant passage 41 below the refrigerant flowing through the refrigerant passage 22b.

  Thereafter, the refrigerant is sucked into the compressor 12 via the four-way valve 13 and the refrigerant passage 26. The compressor 12 compresses the refrigerant flowing from the refrigerant passage 26. In accordance with such a cycle, the refrigerant continuously repeats the compression, condensation, throttle expansion, and evaporation state changes.

  During the heating operation, the heat exchanger 18 adds heat to the ambient air introduced so as to come into contact with the heat exchanger 18 by condensing the refrigerant vapor flowing through the heat exchanger 18. The heat exchanger 18 uses the high-temperature and high-pressure refrigerant that is adiabatically compressed by the compressor 12, and the heat of condensation when the refrigerant gas is condensed into wet refrigerant vapor into the air-conditioning air that circulates in the vehicle interior. To release and heat the interior of the vehicle. Air-conditioning air whose temperature has been increased by receiving heat from the heat exchanger 18 flows into the vehicle interior, thereby heating the vehicle interior.

  As described above, the cooling device 1 according to the present embodiment includes the vapor compression refrigeration cycle 10 that is provided to heat and cool the vehicle interior by exchanging heat with air-conditioning air in the heat exchanger 18. . By switching the flow direction of the refrigerant in the vapor compression refrigeration cycle 10 during the cooling operation and during the heating operation using the four-way valve 13, the single heat exchanger 18 is used to perform the cooling operation and the heating operation. In both cases, the temperature of the air-conditioning air flowing into the vehicle interior can be adjusted appropriately. Since it is not necessary to arrange two heat exchangers for exchanging heat with air for air conditioning, the cost of the cooling device 1 can be reduced and the cooling device 1 can be downsized.

  The refrigerant flows to the cooling unit 30 and cools the HV equipment 31 by exchanging heat with the HV equipment 31. The cooling device 1 cools the HV equipment 31 that is a heat source mounted on the vehicle by using a vapor compression refrigeration cycle 10 for air conditioning in the vehicle interior. The HV equipment 31 is cooled by using the vapor compression refrigeration cycle 10 provided to heat and cool the vehicle interior by exchanging heat with air-conditioning air in the heat exchanger 18.

  It is not necessary to provide a cooling device such as a dedicated water circulation pump or a cooling fan for cooling the HV device 31. Therefore, the configuration necessary for the cooling device 1 of the HV equipment 31 can be reduced and the device configuration can be simplified, so that the manufacturing cost of the cooling device 1 can be reduced. In addition, there is no need to operate a power source such as a pump or a cooling fan for cooling the HV equipment 31, and no power consumption is required to operate the power source. Therefore, power consumption for cooling the HV equipment 31 can be reduced.

  During the cooling operation, the refrigerant has a temperature and pressure that are originally required for cooling the interior of the vehicle at the outlet of the expansion valve 16. The heat exchanger 14 has a heat dissipating capacity that can sufficiently cool the refrigerant. When the refrigerant that has passed through the expansion valve 16 is used for cooling the HV equipment 31, the cooling capacity of the air-conditioning air in the heat exchanger 18 decreases and the cooling capacity for the passenger compartment decreases. In the cooling device 1, the refrigerant is cooled to a sufficiently supercooled state in the heat exchanger 14, and the high-pressure refrigerant at the outlet of the heat exchanger 14 is used for cooling the HV equipment 31. Therefore, the HV device 31 can be cooled without affecting the cooling capability of cooling the air in the passenger compartment.

  The specification of the heat exchanger 14 (that is, the size of the heat exchanger 14 or the heat exchange performance) is such that the temperature of the liquid refrigerant after passing through the heat exchanger 14 is higher than the temperature required for cooling the vehicle interior. Is also determined to decrease. The specification of the heat exchanger 14 is such that the refrigerant has a heat radiation amount that is larger than the heat exchanger of the vapor compression refrigeration cycle when the HV device 31 is not cooled, by the amount of heat that the refrigerant is assumed to receive from the HV device 31. Determined. The cooling device 1 including the heat exchanger 14 having such specifications can appropriately cool the HV equipment 31 without increasing the power of the compressor 12 while maintaining excellent cooling performance in the vehicle interior.

  During the heating operation, the refrigerant is heated by absorbing heat from outside air in the heat exchanger 14, and is heated by absorbing heat from the HV device 31 in the cooling unit 30. By heating the refrigerant in both the cooling unit 30 and the heat exchanger 14, the HV equipment 31 can be appropriately cooled while maintaining excellent heating performance in the vehicle interior. Since the refrigerant is heated in the cooling unit 30 and the waste heat of the HV equipment 31 can be effectively used for indoor heating, the coefficient of performance is improved and the heating operation can be performed more efficiently.

  During the heating operation, the refrigerant that passes through the cooling unit 30 and cools the HV equipment 31 can directly flow to the refrigerant passage 22 between the compressor 12 and the heat exchanger 14 via the refrigerant passage 41. It does not circulate to the heat exchanger 14. By configuring the refrigerant path so that only a part of the refrigerant flows through the heat exchanger 14, the suction pressure of the compressor 12 is increased. The broken lines shown in FIG. 4 indicate the thermodynamic state of the refrigerant when the refrigerant passage 41 is not provided and all the refrigerant flows to the heat exchanger 14. Compared to the case of this broken line, in the present embodiment, the refrigerant pressure at the inlet of the compressor 12 is increased.

  By increasing the pressure of the refrigerant at the inlet of the compressor 12, it is possible to suppress the operation of the compressor 12 under a condition of low compression efficiency. Therefore, for adiabatic compression of the refrigerant in the compressor 12 during heating operation Power consumption can be reduced. Along with this, the discharge gas temperature of the compressor 12 can be lowered, so that deterioration of the components of the compressor 12 and the lubricating oil can be suppressed.

(Embodiment 2)
FIG. 5 is a schematic diagram illustrating a configuration of the cooling device 1 according to the second embodiment. Unlike the first embodiment, the cooling device 1 according to the second embodiment includes a heat exchanger 15 as a third heat exchanger disposed in the refrigerant path between the cooling unit 30 and the expansion valve 16.

  Since the heat exchanger 15 is provided, the refrigerant path between the heat exchanger 14 and the expansion valve 16 has a refrigerant path 23 closer to the heat exchanger 14 than the heat exchanger 15, and the heat exchanger 15. And a refrigerant passage 27 closer to the expansion valve 16. The refrigerant passage 23 is provided as a refrigerant path that circulates between the heat exchanger 14 and the heat exchanger 15. A second passage that is a cooling system of the HV device 31 including the cooling passage 32 is connected in parallel with a refrigerant passage 23 a that forms a part of the refrigerant passage 23.

  The cooling device 1 also includes a gas-liquid separator 60 that separates a wet vapor refrigerant in which a saturated liquid and a saturated vapor are mixed into a vapor-phase refrigerant and a liquid-phase refrigerant. The gas-liquid two-phase refrigerant flowing into the gas-liquid separator 60 is separated into a gas phase and a liquid phase inside the gas-liquid separator 60. The gas-liquid separator 60 separates the refrigerant into a liquid refrigerant liquid 62 and a gaseous refrigerant vapor 61 and temporarily stores them. Inside the gas-liquid separator 60, the refrigerant liquid 62 accumulates on the lower side and the refrigerant vapor 61 accumulates on the upper side.

  The refrigerant path flowing between the heat exchanger 14 and the cooling unit 30 includes a refrigerant passage 33 on the side close to the heat exchanger 14 and a refrigerant passage 34 on the side close to the cooling unit 30. One end of the refrigerant passage 33 is arranged on the ceiling side inside the gas-liquid separator 60 and is arranged in the refrigerant vapor 61. One end of the refrigerant passage 34 is disposed on the bottom side inside the gas-liquid separator 60 and is immersed in the refrigerant liquid 62.

  During the cooling operation, the refrigerant in the state of gas-liquid two-phase wet steam in which saturated liquid and saturated steam are mixed flows out of the heat exchanger 14 and is supplied to the gas-liquid separator 60 through the refrigerant passage 33. . The gas-liquid separator 60 separates the refrigerant that flows out of the heat exchanger 14 and flows through the refrigerant passage 33 into refrigerant vapor 61 that is a gas-phase refrigerant and refrigerant liquid 62 that is a liquid-phase refrigerant. The separated refrigerant liquid 62 flows out of the gas-liquid separator 60 via the refrigerant passage 34. The end of the refrigerant passage 34 disposed in the liquid phase in the gas-liquid separator 60 forms an outlet for the liquid-phase refrigerant from the gas-liquid separator 60. Only the refrigerant liquid 62 is sent out of the gas-liquid separator 60 from the bottom side of the gas-liquid separator 60 via the refrigerant passage 34.

  One end of the refrigerant passage 41 is connected to the refrigerant passage 22. The other end of the refrigerant passage 41 is disposed in the refrigerant vapor 61 inside the gas-liquid separator 60, and only the refrigerant vapor 61 can reliably flow out of the gas-liquid separator 60 via the refrigerant passage 41. It is said that. The refrigerant passage 41 is provided with an expansion valve 47 that expands and expands the refrigerant to reduce the temperature and pressure of the refrigerant. The refrigerant passage 48 communicates the gas-liquid separator 60 and the refrigerant passage 24a. One end of the refrigerant passage 48 is disposed inside the gas-liquid separator 60 and is immersed in the refrigerant liquid 62. The other end of the refrigerant passage 48 is connected to the refrigerant passage 24a. The refrigerant passage 48 is provided with an opening / closing valve 49 that allows or prohibits the refrigerant from flowing into the refrigerant passage 48. During the cooling operation, both the expansion valve 47 and the on-off valve 49 are closed.

  The cooling device 1 further includes an on-off valve 37 that brings the refrigerant passage 33 into a communication state or a non-communication state in the refrigerant path between the heat exchanger 14 and the cooling unit 30, and a first pressure reducer (expansion valve 16). Comprises an expansion valve 38 as a different second pressure reducer. Similarly to the expansion valves 16 and 44, the expansion valve 38 squeezes and expands the refrigerant to reduce the temperature and pressure of the refrigerant. Furthermore, a refrigerant passage 72 that is a refrigerant path that bypasses the expansion valve 38 and an on-off valve 71 that is provided on the refrigerant passage 72 and switches the refrigerant flow to the refrigerant passage 72 are provided.

  During the cooling operation, as shown in FIG. 5, the on-off valve 37 is opened and the on-off valve 71 is closed. The refrigerant condensed in the heat exchanger 14 flows toward the cooling unit 30 via the refrigerant passage 33, the gas-liquid separator 60, the refrigerant passage 34, and the expansion valve 38. The refrigerant flowing to the cooling unit 30 and flowing through the cooling passage 32 takes heat from the HV device 31 and cools the HV device 31. The cooling unit 30 cools the HV equipment 31 using the low-temperature and low-pressure refrigerant that has been discharged from the gas-liquid separator 60 and decompressed by the expansion valve 38.

  During the cooling operation, the refrigerant flows through the vapor compression refrigeration cycle 10 so as to pass through the points A, B, H, C, D, F, and E shown in FIG. The refrigerant circulates in the heat exchangers 14 and 15, the expansion valve 16, and the heat exchanger 18. The refrigerant circulates in the vapor compression refrigeration cycle 10 through a refrigerant circulation passage in which the compressor 12, the heat exchangers 14 and 15, the expansion valve 16 and the heat exchanger 18 are sequentially connected.

  FIG. 6 is a Mollier diagram showing the state of the refrigerant during the cooling operation of the vapor compression refrigeration cycle 10 of the second embodiment. The horizontal axis in FIG. 6 shows the specific enthalpy (unit: kJ / kg) of the refrigerant, and the vertical axis shows the absolute pressure (unit: MPa) of the refrigerant. The curves in the figure are the saturated vapor line and saturated liquid line of the refrigerant. In FIG. 6, it flows into the cooling part 30 via the heat exchanger 14 and the gas-liquid separator 60 from the compressor 12, the HV equipment 31 is cooled, the heat exchanger 15, the expansion valve 16, and the heat exchanger. The thermodynamic state of the refrigerant at each point in the vapor compression refrigeration cycle 10 (ie, points A, B, H, C, D, F, and E) that returns to the compressor 12 via 18 is shown.

  The vapor compression refrigeration cycle 10 of the second embodiment is the same as that of the first embodiment except for the system from the heat exchanger 14 to the expansion valve 16. That is, the state of the refrigerant from the E point in the Mollier diagram shown in FIG. 2 to the B point via the A point, and the refrigerant from the E point to the B point in the Mollier diagram shown in FIG. The state of is the same. Therefore, the state of the refrigerant from point B to point E, which is characteristic of the vapor compression refrigeration cycle 10 of the second embodiment, will be described below.

  The high-temperature and high-pressure refrigerant (point B) adiabatically compressed by the compressor 12 is cooled in the heat exchanger 14. Refrigerant releases sensible heat with constant pressure and becomes dry steam from superheated steam, releases latent heat of condensation and gradually liquefies to become wet steam in a gas-liquid mixed state. The wet vapor refrigerant flowing out of the heat exchanger 14 flows into the gas-liquid separator 60 via the refrigerant passages 23 and 33.

  In the gas-liquid separator 60, the refrigerant in the gas-liquid two-phase state is gas-liquid separated, and only the refrigerant liquid 62, which is a liquid-phase refrigerant, flows out of the gas-liquid separator 60 and flows into the refrigerant passage 34 (point H). It flows into the expansion valve 38. In the expansion valve 38, the refrigerant of the saturated liquid is squeezed and expanded, the specific enthalpy of the refrigerant is not changed, the temperature and the pressure are lowered, and the saturated liquid and the saturated vapor are mixed to become a wet vapor (point C). The refrigerant whose temperature has been lowered in the expansion valve 38 is supplied to the cooling passage 32 of the cooling unit 30. In the cooling unit 30, the HV equipment 31 is cooled by releasing heat to the liquid refrigerant condensed through the heat exchanger 14. By the heat exchange with the HV equipment 31, the refrigerant is heated and the dryness of the refrigerant increases. By receiving latent heat from the HV device 31 and evaporating a part of the refrigerant, the proportion of saturated vapor contained in the wet vapor refrigerant increases (point D).

  Thereafter, the refrigerant flows into the heat exchanger 15. The wet steam of the refrigerant is condensed again by exchanging heat with the outside air in the heat exchanger 15. When all of the refrigerant is condensed, it becomes a saturated liquid, and further releases sensible heat to become a supercooled liquid that is supercooled ( F point). By passing through the expansion valve 16 after that, the refrigerant in the supercooled liquid state is squeezed and expanded, the specific enthalpy does not change, the temperature and pressure are reduced, and the low temperature and low pressure gas-liquid mixed vapor is obtained (E point).

  The liquid-phase refrigerant flowing out of the gas-liquid separator 60 is a truly saturated liquid refrigerant with no excess or deficiency. By taking out only the liquid-phase refrigerant from the gas-liquid separator 60 and flowing it to the cooling unit 30, the HV equipment 31 can be used by maximizing the ability of the heat exchanger 14 arranged on the upstream side of the gas-liquid separator 60. Since it can cool, the cooling device 1 which improved the cooling capability of the HV apparatus 31 can be provided.

  Since the HV device 31 can be cooled by using the refrigerant whose temperature has been lowered by expanding with the expansion valve 38, the HV device 31 can be cooled more efficiently. By optimally selecting the specification of the expansion valve 38, the temperature of the refrigerant that cools the HV device 31 by the cooling unit 30 can be arbitrarily adjusted. The HV device 31 can be cooled by supplying a coolant having a lower temperature suitable for cooling the HV device 31 to the cooling unit 30.

  In the vapor compression refrigeration cycle 10, the high-pressure refrigerant discharged from the compressor 12 is condensed by both the heat exchanger 14 and the heat exchanger 15. By sufficiently cooling the refrigerant in the heat exchanger 15, at the outlet of the expansion valve 16, the refrigerant has a temperature and pressure originally required for cooling the interior of the vehicle. Therefore, the amount of heat received from the outside when the refrigerant evaporates in the heat exchanger 18 can be sufficiently increased. By determining the heat dissipation capability of the heat exchanger 15 that can sufficiently cool the refrigerant, the HV equipment 31 can be cooled without affecting the cooling capability of cooling the air in the passenger compartment. Therefore, both the cooling capacity of the HV device 31 and the cooling capacity for the passenger compartment can be ensured reliably.

  In the vapor compression refrigeration cycle 10 according to the first embodiment, the heat exchanger 14 is disposed between the compressor 12 and the expansion valve 16, and heat corresponding to cooling and cooling of the HV device 31 during cooling operation. The exchange needs to be performed by the heat exchanger 14. Therefore, it is necessary to further cool the refrigerant from the saturated liquid state in the heat exchanger 14 and to cool the refrigerant until it has a predetermined degree of supercooling. When the refrigerant in the supercooled liquid state is cooled, the temperature of the refrigerant approaches the atmospheric temperature and the cooling efficiency of the refrigerant decreases, so the capacity of the heat exchanger 14 needs to be increased. As a result, there is a problem that the size of the heat exchanger 14 increases, which is disadvantageous as the in-vehicle cooling device 1. On the other hand, if the heat exchanger 14 is reduced in size for mounting on a vehicle, the heat dissipation capability of the heat exchanger 14 is also reduced. As a result, the temperature of the refrigerant at the outlet of the expansion valve 16 cannot be sufficiently lowered, and the vehicle compartment is used. There is a risk that the cooling capacity will be insufficient.

  On the other hand, in the vapor compression refrigeration cycle 10 of the second embodiment, the two-stage heat exchangers 14 and 15 are arranged between the compressor 12 and the expansion valve 16, and cooling that is a cooling system of the HV equipment 31. The unit 30 is provided between the heat exchanger 14 and the heat exchanger 15. In the heat exchanger 14, the refrigerant may be cooled to a wet steam state. The saturated liquid refrigerant obtained by gas-liquid separation of the wet vapor refrigerant passes through the expansion valve 38 to reduce the temperature and pressure, and exchanges heat with the HV equipment 31 in the cooling unit 30.

  The refrigerant in the state of wet steam that has received the latent heat of evaporation from the HV device 31 and is partially vaporized is cooled again by the heat exchanger 15. The refrigerant changes its state at a constant temperature until the wet vapor state refrigerant is condensed and completely saturated. The heat exchanger 15 further cools the refrigerant to a degree of supercooling necessary for cooling the vehicle interior. Therefore, compared with Embodiment 1, it is not necessary to increase the degree of supercooling of the refrigerant, and the capacity of the heat exchangers 14 and 15 can be reduced. Therefore, the cooling capacity for the passenger compartment can be ensured, and the size of the heat exchangers 14 and 15 can be reduced, so that the cooling device 1 that is downsized and advantageous for in-vehicle use can be obtained.

  FIG. 7 is a schematic diagram showing the cooling device 1 according to the second embodiment in a state where the four-way valve 13 is switched. 5 and FIG. 7, the path through which the refrigerant flowing into the four-way valve 13 from the outlet of the compressor 12 exits the four-way valve 13 by rotating the four-way valve 13 by 90 ° is the same as in the first embodiment. It has been switched. During the heating operation shown in FIG. 7, the three-way valve 46 is switched between open and closed so that the refrigerant passage 35 and the refrigerant passage 45 communicate with each other and the refrigerant passage 36 and the refrigerant passages 35 and 45 do not communicate with each other. Further, the opening / closing valve 37 is closed, the expansion valve 38 is fully closed (opening degree 0%), the opening degree of the expansion valve 47 is adjusted to appropriately squeeze and expand the refrigerant, and the opening / closing valves 49, 71 are opened.

  Therefore, during the heating operation, the refrigerant that has exchanged heat with the air-conditioning air by the heat exchanger 18 branches from the refrigerant passage 24b into the refrigerant passage 24a and the refrigerant passage 43 in two directions. The refrigerant that has flowed into the refrigerant passage 24 a passes through the expansion valve 16, flows through the refrigerant passage 23, and reaches the refrigerant passage 22 b through the heat exchangers 15 and 14. The refrigerant flowing into the refrigerant passage 43 passes through the expansion valve 44 and flows through the refrigerant passages 45 and 35, passes through the refrigerant passages 34 and 71 via the cooling unit 30, and flows into the gas-liquid separator 60. The refrigerant vapor 61 that has been gas-liquid separated by the gas-liquid separator 60 flows out of the gas-liquid separator 60 and flows through the refrigerant passage 41. The refrigerant flowing through the refrigerant passage 22b and the refrigerant flowing through the refrigerant passage 41 merge at the connection portion of the refrigerant passages 22 and 41 and flow to the refrigerant passage 22a. The refrigerant liquid 62 separated from the gas-liquid separator 60 flows out of the gas-liquid separator 60, flows through the refrigerant passage 48, and is supplied to the expansion valve 16 via the refrigerant passage 24a.

  That is, during the heating operation, the refrigerant flows through the vapor compression refrigeration cycle 10 so as to sequentially pass through the points A, B, E, D, H, K, and J shown in FIG. 12, the heat exchanger 18, the expansion valve 44, and the cooling unit 30 circulate through the refrigerant, and the points A, B, E, M, N, F, I, and G shown in FIG. The refrigerant flows so as to sequentially pass through the refrigerant, and the refrigerant circulates through the compressor 12, the heat exchanger 18, the expansion valve 16, and the heat exchangers 15 and 14. The refrigerant includes a refrigerant circulation passage in which the compressor 12, the heat exchanger 18, the expansion valve 44, and the cooling unit 30 are sequentially connected, the compressor 12, the heat exchanger 18, the expansion valve 16, and the heat exchangers 15 and 14. Are circulated in the vapor compression refrigeration cycle 10 through the refrigerant circulation passages sequentially connected to each other.

  Between the connection point of the refrigerant passage 24a and the refrigerant passage 43 and the connection point of the refrigerant passage 24a and the refrigerant passage 48, the flow rate adjustment valve 52 and the expansion valve 17 are disposed. . The flow rate adjusting valve 52 varies the valve opening degree, and increases or decreases the pressure loss of the refrigerant flowing through the refrigerant passage 24a, so that the flow rate of the refrigerant flowing through the refrigerant passage 24a, the refrigerant passages 43, 45, and 35, and the cooling passage 32 are increased. The flow rate of the refrigerant flowing through the refrigerant passages 34 and 71, the gas-liquid separator 60 and the refrigerant passage 41 in order is arbitrarily adjusted. As with the other expansion valves, the expansion valve 17 expands and expands the refrigerant flowing through the refrigerant passage 24a to reduce the temperature and pressure of the refrigerant.

  Similarly to the flow rate adjustment valve 51 described in the first embodiment, the amount of the refrigerant flowing through the cooling unit 30 can be optimally adjusted using the flow rate adjustment valve 52, so that overcooling of the HV equipment 31 is reliably prevented. be able to. In addition, the pressure loss associated with the refrigerant flow to the cooling unit 30 and the power consumption of the compressor 12 for circulating the refrigerant can be reliably reduced. Furthermore, since the flow rates of the refrigerant passing through the expansion valve 16 and the refrigerant passing through the expansion valve 44 can be adjusted as appropriate, the suction pressure of the compressor 12 is set optimally and the compressor 12 during heating operation is set. The power consumption for adiabatic compression of the refrigerant at can be reduced.

  FIG. 8 is a Mollier diagram showing the state of the refrigerant during the heating operation of the vapor compression refrigeration cycle 10 of the second embodiment. The horizontal axis in FIG. 8 indicates the specific enthalpy (unit: kJ / kg) of the refrigerant, and the vertical axis indicates the absolute pressure (unit: MPa) of the refrigerant. The curves in the figure are the saturated vapor line and saturated liquid line of the refrigerant. In FIG. 8, each point (namely, A, B) in the vapor compression refrigeration cycle 10 that flows from the compressor 12 through the heat exchanger 18, the expansion valve 44, and the cooling unit 30 in order and returns to the compressor 12. , E, D, H, K and J points) shows the thermodynamic state of the refrigerant. In FIG. 8, each point in the vapor compression refrigeration cycle 10 that flows from the compressor 12 through the heat exchanger 18, the expansion valve 16, and the heat exchangers 15 and 14 in order and returns to the compressor 12 ( That is, the thermodynamic state of cooling at points A, B, E, M, N, F, I, and G) is shown.

  The vapor compression refrigeration cycle 10 of the second embodiment is the same as that of the first embodiment except for the system from the heat exchanger 18 outlet to the compressor 12 inlet. That is, the state of the refrigerant from the A point to the E point via the B point in the Mollier diagram shown in FIG. 4, and the refrigerant from the A point to the E point via the B point in the Mollier diagram shown in FIG. The state of is the same. Therefore, the state of the refrigerant from point E to point A, which is unique to the vapor compression refrigeration cycle 10 of the second embodiment, will be described below.

  The refrigerant in the supercooled liquid state that is liquefied by heat exchange with air-conditioning air in the heat exchanger 18 branches from the refrigerant passage 24 b to the refrigerant passage 24 a and the refrigerant passage 43.

  A part of the liquid-phase refrigerant flowing into the refrigerant passage 43 is throttled and expanded by the expansion valve 44, and becomes wet steam in a low-temperature and low-pressure gas-liquid mixed state (point D). The refrigerant whose temperature has been lowered in the expansion valve 16 flows into the cooling passage 32 of the cooling unit 30 via the refrigerant passages 45 and 35 and cools the HV equipment 31. By the heat exchange with the HV equipment 31, the refrigerant is heated and the dryness of the refrigerant increases. By receiving the latent heat from the HV device 31 and evaporating a part of the refrigerant, the ratio of saturated vapor contained in the wet vapor refrigerant increases (H point).

  The wet vapor refrigerant flowing out of the cooling unit 30 flows into the gas-liquid separator 60 via the refrigerant passages 34 and 72. In the gas-liquid separator 60, the refrigerant in the gas-liquid two-phase state is gas-liquid separated into the refrigerant vapor 61 and the refrigerant liquid 62. The gas-liquid separator 60 separates the refrigerant flowing out of the cooling unit 30 and flowing through the refrigerant passage 34 into a gas phase refrigerant and a liquid phase refrigerant. The gas-liquid separator 60 separates the refrigerant vaporized in the cooling unit 30 into a liquid refrigerant liquid 62 and a gaseous refrigerant vapor 61 and temporarily stores them.

  The saturated vapor state refrigerant vapor 61 (point K) flows out of the gas-liquid separator 60, flows into the refrigerant passage 41, and flows into the expansion valve 47. In the expansion valve 47, the refrigerant is throttled and expanded, and the specific enthalpy of the refrigerant does not change, and the temperature and pressure decrease (point J). The refrigerant liquid 62 (point L) in the saturated liquid state flows out of the gas-liquid separator 60 and flows through the refrigerant passage 48 to the refrigerant passage 24a.

  A part of the liquid-phase refrigerant flowing from the refrigerant passage 24b to the refrigerant passage 24a is expanded and expanded in the expansion valve 17, and the temperature and pressure of the refrigerant are lowered (point M). The pressure of the refrigerant after passing through the expansion valve 17 is made equal to the pressure of the refrigerant liquid 62 flowing out from the gas-liquid separator 60. Therefore, the gas-liquid mixed refrigerant that has passed through the expansion valve 17 and the liquid-phase refrigerant that has flowed out of the gas-liquid separator 60 both flow into the refrigerant passage 24 a on the upstream side of the expansion valve 16. The refrigerant flowing from the gas-liquid separator 60 to the refrigerant passage 24a via the refrigerant passage 48 and the refrigerant flowing directly from the refrigerant passage 24b to the refrigerant passage 24a are mixed in the refrigerant passage 24a at the inlet of the expansion valve 16.

  The mixed refrigerant has a pressure equal to the L and M points shown in FIG. The specific enthalpy of the mixed refrigerant is determined by the specific enthalpy and flow rate ratio of each refrigerant before mixing. For example, if the flow rates of the refrigerant before being mixed are equal, the mixed refrigerant has a specific enthalpy intermediate between the specific enthalpy at the L point and the specific enthalpy at the M point (N point). At the point N, the refrigerant has a pressure equal to that of the refrigerant at the L and M points, and has a specific enthalpy greater than or equal to the refrigerant in the saturated liquid state at the L point and less than that in the gas-liquid mixed state at the M point.

  The mixed refrigerant then flows to the expansion valve 16 and is expanded by passing through the expansion valve 16 to become wet steam in a low-temperature and low-pressure gas-liquid mixed state (point F). The refrigerant whose temperature has been lowered in the expansion valve 16 flows into the heat exchanger 15 via the refrigerant passage 27. A wet steam refrigerant flows into the tube of the heat exchanger 15. When the refrigerant circulates in the tube, it absorbs the heat of the outside air as the latent heat of vaporization via the fins, and evaporates with a constant pressure. The heat exchange with the outside air in the heat exchanger 15 heats the refrigerant and increases the dryness of the refrigerant. When the latent heat is received in the heat exchanger 15 and a part of the refrigerant is vaporized, the ratio of the saturated steam contained in the wet steam refrigerant increases (point I).

  The wet steam refrigerant that has flowed out of the heat exchanger 15 flows into the heat exchanger 14 via the refrigerant passage 23. A wet steam refrigerant flows into the tube of the heat exchanger 14. When the refrigerant circulates in the tube, the refrigerant is heated by absorbing the heat of the outside air as latent heat of evaporation via the fins, evaporates while maintaining the equal pressure, and the dryness of the refrigerant increases. When all the refrigerants are dry and become saturated vapor, the refrigerant vapor further rises in temperature due to sensible heat and becomes superheated vapor (point G).

  The refrigerant (point J) that has been expanded and reduced in the expansion valve 47 has a pressure equal to that of the superheated vapor refrigerant (point G) that flows through the refrigerant passage 22b via the heat exchanger 14. Therefore, both the refrigerant flowing through the refrigerant passage 41 and the refrigerant flowing through the refrigerant passage 22b flow into the refrigerant passage 22a and are mixed. The mixed refrigerant has a pressure equal to the pressure at points J and G shown in FIG. The specific enthalpy of the mixed refrigerant is determined by the specific enthalpy and flow rate ratio of the refrigerant flowing through each of the refrigerant passages 22b and 41. For example, if the flow rates of the refrigerant before being mixed are equal, the mixed refrigerant has a specific enthalpy intermediate between the specific enthalpy at point J and the specific enthalpy at point G (point A).

  The refrigerant in the saturated liquid state at the outlet of the gas-liquid separator 60 is circulated to the refrigerant passage 34 during the cooling operation and is circulated to the refrigerant passage 48 during the heating operation, so that the refrigerant vapor in the gas phase is converted into the refrigerant passage 34, Inflow to 48 can be suppressed. Therefore, it is possible to suppress an increase in pressure loss due to an increase in the flow rate of the refrigerant, and it is possible to reduce the power consumption of the compressor 12 for circulating the refrigerant, thereby avoiding deterioration of the performance of the vapor compression refrigeration cycle 10. it can.

  A refrigerant liquid 62 in a saturated liquid state is stored inside the gas-liquid separator 60. The gas-liquid separator 60 functions as a liquid accumulator that temporarily stores the refrigerant liquid 62 therein. By storing a predetermined amount of the refrigerant liquid 62 in the gas-liquid separator 60, the flow rate of the refrigerant flowing from the gas-liquid separator 60 to the cooling unit 30 can be maintained when switching from the heating operation to the cooling operation. Since the gas-liquid separator 60 has a liquid reservoir function, it is possible to absorb a change in the refrigerant flow rate that temporarily decreases the flow rate of the refrigerant flowing from the heat exchanger 14 to the gas-liquid separator 60 when switching between heating and cooling. Therefore, it is possible to avoid a shortage of the refrigerant supply amount to the cooling unit 30 when switching from heating to cooling, and to stabilize the cooling performance of the HV equipment 31.

  By configuring the refrigerant path so that only a part of the refrigerant flows through the heat exchanger 14 during the heating operation, the pressure of the refrigerant at the inlet of the compressor 12 is increased, and the compressor is operated under a condition where the compression efficiency is low. Since it can suppress that 12 operates, the power consumption for the adiabatic compression of the refrigerant | coolant with the compressor 12 at the time of heating operation can be reduced.

  In the first embodiment, the refrigerant that has flowed out of the heat exchanger 14 needs to be mixed with the refrigerant in a wet vapor state that has flowed out of the cooling unit 30. Therefore, in order to distribute the refrigerant in the superheated steam state to the refrigerant passage 22a, it is necessary to further heat the refrigerant in the heat exchanger 14 from the saturated vapor state and to heat the refrigerant until the refrigerant has a predetermined superheat degree. . Therefore, it is necessary to increase the capacity of the heat exchanger 14, which increases the size of the heat exchanger 14, which is disadvantageous as the in-vehicle cooling device 1.

  On the other hand, in the vapor compression refrigeration cycle 10 of the second embodiment, the refrigerant flowing out of the heat exchanger 14 is mixed with the dry saturated vapor refrigerant separated by the gas-liquid separator 60, and the compressor 12. Therefore, it is not necessary to increase the degree of superheat of the refrigerant at the outlet of the heat exchanger 14. For example, the degree of superheat of the refrigerant (point G) at the outlet of the heat exchanger 14 is adjusted so that the state of superheated steam having a specific enthalpy substantially equal to the specific enthalpy of the refrigerant expanded by the expansion valve 47 (point J) is obtained. May be. Therefore, compared with Embodiment 1, the capacity | capacitance of the heat exchangers 14 and 15 can be reduced more. Therefore, since the size of the heat exchangers 14 and 15 can be reduced, it is possible to obtain the cooling device 1 that is downsized and advantageous for in-vehicle use.

  Since the two-stage heat exchangers 14 and 15 are disposed between the compressor 12 and the expansion valve 16, the refrigerant is heated by absorbing heat from the outside air in both the heat exchangers 14 and 15 during the heating operation. . By heating the refrigerant in both the cooling unit 30 and the heat exchangers 14 and 15, the heat exchange capacity of each of the heat exchangers 14 and 15 can be reduced. Since the refrigerant can be heated to the state of sufficient superheated steam at the outlet of the heat exchanger 14, excellent heating performance in the vehicle interior can be maintained.

  In the second embodiment, the example of the cooling device 1 including the expansion valve 38 and the refrigerant passage 72 that bypasses the expansion valve 38 has been described. If the expansion valve 38 can be selected such that the refrigerant flowing into the cooling unit 30 during the cooling operation is throttled and expanded by the expansion valve 38 and the pressure loss when the refrigerant passes through the expansion valve 38 during the heating operation can be selected. The passage 72 may not be provided.

(Embodiment 3)
FIG. 9 is a schematic diagram illustrating a configuration of the cooling device 1 according to the third embodiment. The cooling device 1 of the third embodiment has the same configuration as that of the second embodiment. However, during heating operation, the on-off valve 49 is closed, the expansion valve 16 is fully closed (opening degree 0%), and the expansion valve 47 is fully opened. This is different from the second embodiment in that (the opening degree is 100%).

  At this time, the entire amount of refrigerant adiabatically compressed by the compressor 12 and heat-exchanged with the air-conditioning air by the heat exchanger 18 flows into the refrigerant passage 43 from the refrigerant passage 24b. The refrigerant flowing into the refrigerant passage 43 passes through the expansion valve 44 and is squeezed and expanded, passes through the cooling passage 32 of the cooling unit 30, cools the HV device 31, and is separated into gas and liquid by the gas-liquid separator 60. Only the vapor 61 flows out of the gas-liquid separator 60 and returns to the compressor 12 via the refrigerant passages 41 and 22a.

  That is, during the heating operation, the refrigerant flows through the vapor compression refrigeration cycle 10 so as to pass through the points A, B, E, D, and H shown in FIG. 9 in order, and the compressor 12 and the heat exchanger 18 are passed through. Then, the refrigerant circulates through the expansion valve 44 and the cooling unit 30. The refrigerant circulates in the vapor compression refrigeration cycle 10 through a refrigerant circulation passage in which the compressor 12, the heat exchanger 18, the expansion valve 44, and the cooling unit 30 are sequentially connected.

  FIG. 10 is a Mollier diagram showing the state of the refrigerant during the heating operation of the vapor compression refrigeration cycle 10 of the third embodiment. The horizontal axis in FIG. 10 indicates the specific enthalpy (unit: kJ / kg) of the refrigerant, and the vertical axis indicates the absolute pressure (unit: MPa) of the refrigerant. The curves in the figure are the saturated vapor line and saturated liquid line of the refrigerant. In FIG. 10, each point in the vapor compression refrigeration cycle 10 (that is, A, B) that flows from the compressor 12 through the heat exchanger 18, the expansion valve 44, and the cooling unit 30 in order and returns to the compressor 12. , E, D, and H points) shows the thermodynamic state of the refrigerant.

  As shown in FIG. 10, at the inlet of the compressor 12, the refrigerant is in a dry saturated vapor state (point A). The refrigerant in the dry saturated vapor state is sucked into the compressor 12 and adiabatically compressed along the isentropic line in the compressor 12. As the compressor is compressed, the pressure and temperature of the refrigerant rise and become high-temperature and high-pressure superheated steam with a high degree of superheat (point B), and the refrigerant flows to the heat exchanger 18. The high-pressure refrigerant vapor that has entered the heat exchanger 18 is cooled in the heat exchanger 18, and changes from superheated steam to dry saturated vapor while maintaining the constant pressure, releases latent heat of condensation, gradually liquefies, and wets in a gas-liquid mixed state. When it becomes steam and all of the refrigerant condenses, it becomes a saturated liquid, further releases sensible heat and becomes a supercooled liquid (point E).

  The high-pressure liquid-phase refrigerant liquefied by the heat exchanger 18 flows into the refrigerant passage 43 from the refrigerant passage 24b. The refrigerant in the supercooled liquid state flowing into the refrigerant passage 23 is squeezed and expanded in the expansion valve 44, the specific enthalpy of the refrigerant does not change, and the temperature and pressure are reduced. (D point). The refrigerant whose temperature has been lowered in the expansion valve 44 flows into the cooling passage 32 of the cooling unit 30 via the refrigerant passages 45 and 35 and cools the HV equipment 31. By the heat exchange with the HV equipment 31, the refrigerant is heated and the dryness of the refrigerant increases. By receiving the latent heat from the HV device 31 and evaporating a part of the refrigerant, the ratio of saturated vapor contained in the wet vapor refrigerant increases (H point).

  The wet vapor refrigerant flowing out of the cooling unit 30 is gas-liquid separated into the refrigerant vapor 61 and the refrigerant liquid 62 by the gas-liquid separator 60. Only the saturated vapor state refrigerant vapor 61 flows out from the gas-liquid separator 60, flows into the refrigerant passage 41, and is sucked into the compressor 12 via the refrigerant passage 22a, the four-way valve 13 and the refrigerant passage 26 (A point). The compressor 12 compresses the refrigerant flowing from the refrigerant passage 26. In accordance with such a cycle, the refrigerant continuously repeats the compression, condensation, throttle expansion, and evaporation state changes.

  By setting the opening and closing of the valves as shown in FIG. 9, all the refrigerant can be circulated from the refrigerant passage 24b to the refrigerant passage 43 during the heating operation. That is, it can be set so that the low-temperature and low-pressure refrigerant that has passed through the expansion valve 16 does not flow to the heat exchangers 15 and 14 during the heating operation.

  For example, under conditions where the outside air temperature is low, such as below the freezing point, it is difficult to absorb heat from the atmosphere in the heat exchangers 14 and 15 during heating operation, so that the refrigerant pressure decreases. When the refrigerant pressure is too low, the power consumption of the compressor 12 increases, the gas discharged from the compressor 12 becomes high temperature, the insulating material and the lubricating oil deteriorate, and the heat exchangers 14 and 15 are frosted. Therefore, the subject that the air_conditionaing | cooling operation (defrost operation) for removing frost is needed arises.

  Therefore, under the low outside air temperature condition, the valve opening / closing setting is switched so that the refrigerant does not flow through the heat exchangers 14 and 15 during the heating operation as shown in the third embodiment. If it does in this way, cooling of HV equipment 31 can be secured by circulating a refrigerant to cooling part 30, and since air for air-conditioning can be fully heated with heat exchanger 18, heating performance can be secured. In addition, the above-described problems can be avoided.

(Embodiment 4)
FIG. 11 is a schematic diagram illustrating a configuration of the cooling device 1 according to the fourth embodiment. The cooling device 1 according to the fourth embodiment is different from the second embodiment in that an ejector 80 is provided. The ejector 80 includes a refrigerant passage 81 branched from the refrigerant passage 43, and the cooling portion 30 with respect to the expansion valve 38 in the refrigerant passage 34 that is a refrigerant passage that circulates between the gas-liquid separator 60 and the cooling portion 30. The refrigerant passage 83 branched from the side adjacent to the refrigerant passage 34 and the refrigerant passage 85 branched from the side closer to the gas-liquid separator 60 to the expansion valve 38 in the refrigerant passage 34 are connected.

  In the refrigerant passage 81, an on-off valve 82 that allows or prohibits the refrigerant flow through the refrigerant passage 81 is disposed. In the refrigerant passage 83, an on-off valve 84 that allows or prohibits the refrigerant flow through the refrigerant passage 83 is disposed. In the refrigerant passage 85, an on-off valve 86 that allows or prohibits the refrigerant flow through the refrigerant passage 85 is disposed.

  During the cooling operation shown in FIG. 11, the on-off valves 82, 84, 86 are all closed. Therefore, the refrigerant circulates in the vapor compression refrigeration cycle 10 while changing the state as in FIG. Accordingly, as in the second embodiment, only the liquid-phase refrigerant is taken out from the gas-liquid separator 60, and the HV device 31 can be cooled using the refrigerant whose temperature has been lowered by expansion by the expansion valve 38. The device 31 can be cooled more efficiently.

  FIG. 12 is a schematic diagram illustrating the cooling device 1 according to the fourth embodiment in a state where the four-way valve 13 is switched. During the heating operation shown in FIG. 12, all of the on-off valves 82, 84, 86 are opened, and the expansion valve 38 is fully closed. Therefore, the refrigerant flows through the ejector 80. The ejector 80 uses the high-pressure refrigerant before passing through the expansion valve 44 as a driving flow, and uses the refrigerant after passing through the expansion valve 44 and cooling the HV device 31 in the cooling unit 30 as a secondary flow. It functions as a booster that mixes the flow and raises the pressure of the low-pressure refrigerant flowing from the cooling unit 30 toward the gas-liquid separator 60.

  The high-pressure refrigerant flowing into the ejector 80 from the refrigerant passage 43 via the refrigerant passage 81 is ejected from the nozzle as a driving flow, and the refrigerant passage 83 is generated by the negative pressure generated in the ejector 80 due to the ejection of the driving flow and the viscosity of the driving flow. Then, the refrigerant is sucked into the ejector 80. Inside the ejector 80, the refrigerant flowing in from the refrigerant passage 81 and the refrigerant flowing in from the refrigerant passage 83 are completely mixed, and then the pressure is increased by passing through the diffuser and is discharged to the refrigerant passage 85. The refrigerant whose pressure has decreased after passing through the expansion valve 44 is pressurized by the ejector 80 and flows to the gas-liquid separator 60 via the refrigerant passages 85 and 34.

  FIG. 13 is a Mollier diagram showing the state of the refrigerant during the heating operation of the vapor compression refrigeration cycle 10 of the fourth embodiment. The horizontal axis in FIG. 13 indicates the specific enthalpy (unit: kJ / kg) of the refrigerant, and the vertical axis indicates the absolute pressure (unit: MPa) of the refrigerant. The curves in the figure are the saturated vapor line and saturated liquid line of the refrigerant.

  In FIG. 13, the refrigerant flows into the refrigerant passage 43 from the outlet of the heat exchanger 18, is throttled and expanded by the expansion valve 44, is cooled by the ejector 80 after cooling the HV device 31, and is separated by the gas-liquid separator 60. The refrigerant vapor 61 thus discharged flows out of the gas-liquid separator 60 and returns to the compressor 12 via the refrigerant passages 41 and 22a (that is, A, B, E, D, and so on). The thermodynamic state of the refrigerant at points C, H, K and J) is shown. In FIG. 13, each point in the vapor compression refrigeration cycle 10 that flows from the compressor 12 through the heat exchanger 18, the expansion valve 16, and the heat exchangers 15 and 14 in order and returns to the compressor 12 ( That is, the thermodynamic state of cooling at points A, B, E, M, N, F, I, and G) is shown.

  As shown in FIG. 13, the superheated vapor refrigerant (point A) sucked into the compressor 12 is adiabatically compressed along the isentropic line in the compressor 12. As the compressor is compressed, the pressure and temperature of the refrigerant rise and become high-temperature and high-pressure superheated steam with a high degree of superheat (point B), and the refrigerant flows to the heat exchanger 18.

  The high-pressure refrigerant vapor that has entered the heat exchanger 18 is cooled in the heat exchanger 18, and changes from superheated steam to dry saturated vapor while maintaining the constant pressure, releases latent heat of condensation, gradually liquefies, and wets in a gas-liquid mixed state. When it becomes steam and all of the refrigerant condenses, it becomes a saturated liquid, further releases sensible heat and becomes a supercooled liquid (point E). The high-pressure liquid refrigerant liquefied by the heat exchanger 18 branches from the refrigerant passage 24b to the refrigerant passage 24a and the refrigerant passage 43.

  A part of the liquid-phase refrigerant flowing into the refrigerant passage 43 flows into the expansion valve 44 via the refrigerant passage 43. In the expansion valve 44, the refrigerant in the supercooled liquid state is squeezed and expanded, the specific enthalpy of the refrigerant does not change, the temperature and pressure are reduced, and it becomes wet steam in a low-temperature and low-pressure gas-liquid mixed state (point D). The refrigerant whose temperature has been lowered in the expansion valve 44 flows into the cooling passage 32 of the cooling unit 30 via the refrigerant passages 45 and 35 and cools the HV equipment 31. By the heat exchange with the HV equipment 31, the refrigerant is heated and the dryness of the refrigerant increases. By receiving latent heat from the HV device 31 and vaporizing a part of the refrigerant, the ratio of saturated vapor contained in the refrigerant in the wet vapor state increases (point C).

  The refrigerant warmed in the cooling unit 30 is pressurized by the ejector 80. The high-pressure refrigerant that does not pass through the expansion valve 44 is supplied from the refrigerant passage 81 to the ejector 80, and the low-pressure refrigerant that has passed through the expansion valve 44 and the pressure has decreased is supplied from the refrigerant passage 83 to the ejector 80, whereby the low-pressure refrigerant is boosted. And the temperature of the low-pressure refrigerant rises. The ejector 80 introduces the low-pressure refrigerant into the ejector 80 using the differential pressure between the high-pressure refrigerant and the low-pressure refrigerant by using the high-pressure refrigerant as the driving gas and the low-pressure refrigerant as the suction gas, and increases the pressure of the low-pressure refrigerant. A refrigerant having a higher pressure is discharged (point H).

  Since the ejector 80 is used as a booster for boosting the low-pressure refrigerant, there is no need to drive the compressor that requires power consumption to boost the refrigerant. Therefore, an increase in power consumption can be avoided. Since the ejector 80 has a simple structure in which a nozzle and a diffuser are combined and does not have a moving part, a booster excellent in durability and reliability can be provided.

  Thereafter, the refrigerant flows into the gas-liquid separator 60 via the refrigerant passages 85 and 34. In the gas-liquid separator 60, the refrigerant in the gas-liquid two-phase state is gas-liquid separated into the refrigerant vapor 61 and the refrigerant liquid 62. The dry saturated vapor state refrigerant vapor 61 (point K) separated by the gas-liquid separator 60 flows out from the gas-liquid separator 60, flows into the refrigerant passage 41, and flows into the expansion valve 47. In the expansion valve 47, the refrigerant is throttled and expanded, and the specific enthalpy of the refrigerant does not change, and the temperature and pressure decrease (point J). The refrigerant liquid 62 (point L) in the saturated liquid state flows out of the gas-liquid separator 60 and flows through the refrigerant passage 48 to the refrigerant passage 24a.

  A part of the liquid-phase refrigerant flowing from the refrigerant passage 24b to the refrigerant passage 24a is expanded and expanded in the expansion valve 17, and the temperature and pressure of the refrigerant are lowered (point M). The pressure of the refrigerant after passing through the expansion valve 17 is made equal to the pressure of the refrigerant liquid 62 flowing out from the gas-liquid separator 60. Therefore, the gas-liquid mixed refrigerant that has passed through the expansion valve 17 and the liquid-phase refrigerant that has flowed out of the gas-liquid separator 60 both flow into the refrigerant passage 24 a on the upstream side of the expansion valve 16. The refrigerant flowing from the gas-liquid separator 60 to the refrigerant passage 24a via the refrigerant passage 48 and the refrigerant flowing directly from the refrigerant passage 24b to the refrigerant passage 24a are mixed in the refrigerant passage 24a at the inlet of the expansion valve 16.

  The mixed refrigerant has a pressure equal to the L and M points shown in FIG. The specific enthalpy of the mixed refrigerant is determined by the specific enthalpy and flow rate ratio of each refrigerant before mixing. For example, if the flow rates of the refrigerant before being mixed are equal, the mixed refrigerant has a specific enthalpy intermediate between the specific enthalpy at the L point and the specific enthalpy at the M point (N point). At the point N, the refrigerant has a pressure equal to that of the refrigerant at the L and M points, and has a specific enthalpy greater than or equal to the refrigerant in the saturated liquid state at the L point and less than that in the gas-liquid mixed state at the M point.

  The mixed refrigerant then flows to the expansion valve 16 and passes through the expansion valve 16 so that the refrigerant is throttled and expanded in the expansion valve 16. The specific enthalpy of the refrigerant does not change, and the temperature and pressure are reduced. It becomes wet steam in the state (point F). The refrigerant whose temperature has been lowered in the expansion valve 16 flows into the heat exchanger 15 via the refrigerant passage 27. In the heat exchanger 15, the latent heat is received from the outside air, the refrigerant is heated, and a part of the refrigerant is vaporized, whereby the ratio of saturated vapor contained in the wet vapor refrigerant increases and the dryness of the refrigerant increases. (Point I).

  The wet steam refrigerant that has flowed out of the heat exchanger 15 flows into the heat exchanger 14 via the refrigerant passage 23. When the refrigerant flows through the heat exchanger 14, it is heated by absorbing the heat of the outside air as latent heat of vaporization, evaporates while maintaining the same pressure, and the dryness of the refrigerant increases. When all the refrigerant is dry and becomes saturated vapor, the refrigerant vapor further rises in temperature due to sensible heat and becomes superheated vapor (point G).

  The refrigerant (point J) that has been expanded and reduced in the expansion valve 47 has a pressure equal to that of the superheated vapor refrigerant (point G) that flows through the refrigerant passage 22b via the heat exchanger 14. Therefore, both the refrigerant flowing through the refrigerant passage 41 and the refrigerant flowing through the refrigerant passage 22b flow into the refrigerant passage 22a and are mixed. The mixed refrigerant has a pressure equal to the pressure at points J and G shown in FIG. The specific enthalpy of the mixed refrigerant is determined by the specific enthalpy and flow rate ratio of the refrigerant flowing through each of the refrigerant passages 22b and 41. For example, if the flow rates of the refrigerant before being mixed are equal, the mixed refrigerant has a specific enthalpy intermediate between the specific enthalpy at point J and the specific enthalpy at point G (point A). Thereafter, the refrigerant is sucked into the compressor 12 via the four-way valve 13 and the refrigerant passage 26. The compressor 12 compresses the refrigerant flowing from the refrigerant passage 26.

  The temperature and pressure of the refrigerant at the point H boosted by the ejector 80 are equal to the temperature and pressure of the refrigerant at the point H on the inlet side of the gas-liquid separator 60 in the cooling device 1 having no configuration shown in FIG. By doing so, the temperature and pressure of the refrigerant that cools the HV equipment 31 can be lowered. That is, the temperature and pressure of the refrigerant flowing from the point D to the point C shown in FIG. 13 are compared with the temperature and pressure of the refrigerant flowing from the point D to the point H shown in FIG. , Relatively low. Therefore, the temperature difference between the HV device 31 and the refrigerant flowing through the cooling unit 30 increases, and the amount of heat absorbed from the HV device 31 by the refrigerant increases.

  Since the amount of heat given from the HV device 31 to the refrigerant in the cooling unit 30 increases, the amount of heat that the refrigerant absorbs from the outside air in the heat exchangers 14 and 15 can be relatively reduced. In this case, since the temperature difference between the outside air and the refrigerant can be reduced, the temperature and pressure of the refrigerant flowing via the expansion valve 16 and the heat exchangers 15 and 14 can be relatively increased. That is, when FIG. 13 and FIG. 8 are compared, the pressure of the refrigerant from the F point to the G point is higher in FIG.

  As described above, the pressure of the refrigerant flowing through the refrigerant passage 41 by the expansion of the expansion valve 47 is made equal to the pressure of the refrigerant flowing through the refrigerant passage 22b. In other words, the pressure of the refrigerant flowing into the compressor 12 is adjusted to the pressure of the refrigerant at point G. Therefore, when FIG. 13 is compared with FIG. 8, the pressure at point A is higher in FIG. The pressure of the refrigerant at the inlet of the compressor 12 can be further increased by increasing the pressure of the refrigerant after the HV device 31 is cooled by the cooling unit 30 using the ejector 80. Therefore, the power consumption of the compressor 12 can be further reduced as compared with the first to third embodiments.

  In the first to fourth embodiments, the cooling device 1 that cools an electric device mounted on a vehicle using the HV device 31 as an example has been described. The electric device is not limited to the exemplified electric device such as an inverter and a motor generator as long as it is an electric device that generates heat at least by operation, and may be any electric device. When there are a plurality of electrical devices to be cooled, it is desirable that the plurality of electrical devices have a common temperature range to be cooled. The target temperature range for cooling is a temperature range suitable as a temperature environment for operating the electrical equipment.

  Furthermore, the heat generation source cooled by the cooling device 1 of the present invention is not limited to an electric device mounted on a vehicle, and may be an arbitrary device that generates heat, or a part that generates heat from an arbitrary device.

  Although the embodiments of the present invention have been described above, the configurations of the embodiments may be appropriately combined. In addition, it should be considered that the embodiment disclosed this time is illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The cooling device of the present invention is an electrical device using a vapor compression refrigeration cycle for cooling the interior of a vehicle such as a hybrid vehicle, a fuel cell vehicle, and an electric vehicle equipped with electrical devices such as a motor generator and an inverter. It can be applied particularly advantageously to cooling.

  DESCRIPTION OF SYMBOLS 1 Cooling device, 10 Vapor compression refrigeration cycle, 12 Compressor, 13 Four-way valve, 14, 15, 18 Heat exchanger, 16, 17, 38, 44, 47 Expansion valve, 21, 22, 22a, 22b, 23, 23a, 24, 24a, 24b, 25, 26, 27, 33, 34, 35, 36, 41, 43, 45, 48, 72, 81, 83, 85 Refrigerant passage, 30 cooling section, 31 HV equipment, 32 cooling Passage, 37, 49, 71, 82, 84, 86 On-off valve, 42, 46 Three-way valve, 51, 52 Flow control valve, 60 Gas-liquid separator, 61 Refrigerant vapor, 62 Refrigerant liquid, 80 Ejector, 90 Duct, 91 Duct inlet, 92 duct outlet, 93 fans.

Claims (7)

A cooling device for cooling a heat source,
A compressor for circulating the refrigerant;
A first heat exchanger for exchanging heat between the refrigerant and outside air;
A decompressor for decompressing the refrigerant;
A second heat exchanger that exchanges heat between the refrigerant and air-conditioning air;
A four-way valve that switches between the flow of the refrigerant from the compressor toward the first heat exchanger and the flow of the refrigerant from the compressor toward the second heat exchanger;
A first passage and a second passage which are paths of the refrigerant connected in parallel between the first heat exchanger and the decompressor;
A cooling unit provided on the second passage for cooling the heat generation source using the refrigerant;
A first series passage that communicates the refrigerant path between the compressor and the first heat exchanger and the second passage on the side close to the first heat exchanger with respect to the cooling unit. When,
A second communication path that communicates the refrigerant path between the pressure reducer and the second heat exchanger and the second passage on the side close to the pressure reducer with respect to the cooling unit; A cooling device.   The cooling device according to claim 1, further comprising a third heat exchanger that is provided in a path of the refrigerant flowing between the cooling unit and the decompressor and exchanges heat between the refrigerant and outside air.   The cooling device according to claim 1, further comprising a second pressure reducer provided in a path of the refrigerant flowing between the first heat exchanger and the cooling unit.   The cooling device according to any one of claims 1 to 3, further comprising a gas-liquid separator disposed in the second passage on a side close to the first heat exchanger with respect to the cooling unit.   The cooling device according to claim 4, wherein one end of the first series passage is disposed in a gas phase of the gas-liquid separator.   The cooling device according to any one of claims 1 to 5, further comprising a booster that increases a pressure of the refrigerant flowing from the cooling unit toward the first series passage.   The refrigerant path is switched so that the refrigerant does not flow through the first heat exchanger when the four-way valve is set so that the refrigerant flows from the compressor toward the second heat exchanger. The cooling device according to any one of claims 1 to 6.

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