Temperature control system and control method thereof

Abstract

A temperature control system capable of defrosting while minimizing heat loss to the outside air. [Solution] The temperature adjustment system 1 includes a hot water circuit 5 and a cold water circuit 7 through which a heat medium circulates that exchanges heat with a refrigerant in a condenser 11 and an evaporator 13. The hot water circuit 5 and the cold water circuit 7 include an indoor heat exchanger 18 that exchanges heat between hot water and indoor air, and an outdoor heat exchanger 22 that exchanges heat between cold water and outdoor air. The control unit has a heater mode in which hot water flowing out from the condenser 11 is guided to the indoor heat exchanger 18, but cold water flowing out from the evaporator 13 is not guided to the outdoor heat exchanger 22, and a defrost operation mode in which cold water is guided from the evaporator 13 to the outdoor heat exchanger 22 when frost forms on the outdoor heat exchanger 22 in the heat pump mode.

Description

[Technical Field]

[0001] The present disclosure relates to a temperature control system suitable for use in, for example, a vehicle, and a control method thereof. [Background technology]

[0002] Patent Document 1 discloses a vehicle air conditioner that generates hot water and cold water using a refrigeration cycle to condition the vehicle. In this vehicle air conditioner, in a heating and defrosting mode (FIG. 2 of the document), hot water heated in a condenser is circulated through an exterior heat exchanger to perform defrosting (paragraph

[0038] of the document). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7463119 Summary of the Invention [Problem to be solved by the invention]

[0004] Flowing hot water heated by the condenser through the outdoor heat exchanger is effective in melting frost on the outdoor heat exchanger, but the heat generated may be excessive (e.g., 50°C) for defrosting. For example, when hot water is circulated through the outdoor heat exchanger, initially, only the temperature of the hot water inlet side of the outdoor heat exchanger rises, while the temperature of the hot water outlet side does not rise sufficiently. Therefore, defrosting must be performed over time until the temperature of the hot water outlet side rises. If the temperature rises to the hot water outlet side, hot water continues to flow even though defrosting has already been completed at the hot water inlet side, resulting in significant heat loss to the outside air. Therefore, defrosting by flowing hot water through the outdoor heat exchanger wastes heat and may result in insufficient heating of the room.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a temperature control system and a control method thereof that can perform defrosting while minimizing heat loss to the outside air as much as possible. [Means for solving the problem]

[0006] A temperature control system according to one aspect of the present disclosure includes a refrigerant circuit having a compressor that compresses a refrigerant, a high-pressure side heat exchanger that dissipates heat from the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant that has dissipated heat in the high-pressure side heat exchanger, and a low-pressure side heat exchanger that evaporates the refrigerant expanded in the expansion valve, a heat medium circuit in which a heat medium that exchanges heat with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger circulates, and a control unit that controls the refrigerant circuit and the heat medium circuit, wherein the heat medium circuit includes a temperature control device that exchanges heat between the heat medium and a temperature control target, and an outdoor heat exchanger that exchanges heat between the heat medium and outdoor air, and the control unit controls the high-pressure side heat exchanger. a heater mode in which the heat medium flowing out of the pressure-side heat exchanger is guided to the temperature control device, and the heat medium flowing out of the low-pressure-side heat exchanger is not guided to the outdoor heat exchanger; a heat pump mode in which the heat medium flowing out of the high-pressure-side heat exchanger is guided to the temperature control device, and the heat medium flowing out of the low-pressure-side heat exchanger is guided to the outdoor heat exchanger; and a defrosting operation mode in which, when frost forms on the outdoor heat exchanger in the heat pump mode, part or all of the heat medium from the low-pressure-side heat exchanger is guided to the outdoor heat exchanger, and part or all of the heat medium from the high-pressure-side heat exchanger is guided to the temperature control device. In the defrosting operation mode, the heat medium that has left the outdoor heat exchanger returns to the low-pressure side heat exchanger without passing through the high-pressure side heat exchanger. .

[0007] A control method for a temperature adjustment system according to one aspect of the present disclosure is a control method for a temperature adjustment system including a refrigerant circuit having a compressor that compresses a refrigerant, a high-pressure side heat exchanger that dissipates heat from the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant that has dissipated heat in the high-pressure side heat exchanger, and a low-pressure side heat exchanger that evaporates the refrigerant expanded in the expansion valve, and a heat medium circuit in which a heat medium that exchanges heat with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger circulates, the heat medium circuit including a temperature adjustment device that exchanges heat between the heat medium and a temperature adjustment target, and an outdoor heat exchanger that exchanges heat between the heat medium and outdoor air, a heater mode in which the heat medium discharged from the temperature control device is guided to the temperature control device and the heat medium flowing out from the temperature control device is guided to the low-pressure side heat exchanger without being guided to the outdoor heat exchanger; a heat pump mode in which the heat medium flowing out from the high-pressure side heat exchanger is guided to the temperature control device and the heat medium flowing out from the low-pressure side heat exchanger is guided to the outdoor heat exchanger; and a defrosting operation mode in which, when frost forms on the outdoor heat exchanger in the heat pump mode, part or all of the heat medium from the low-pressure side heat exchanger is guided to the outdoor heat exchanger and part or all of the heat medium from the high-pressure side heat exchanger is guided to the temperature control device. In the defrosting operation mode, the heat medium that has left the outdoor heat exchanger returns to the low-pressure side heat exchanger without passing through the high-pressure side heat exchanger. . [Effects of the Invention]

[0008] Defrosting can be performed while minimizing heat loss to the outside air. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a vehicle air conditioner according to a first embodiment of the present disclosure, showing a heater mode. [Figure 2] 2 is a schematic diagram illustrating a defrosting operation mode of the vehicle air conditioner of FIG. 1. FIG. [Figure 3] FIG. 6 is a schematic configuration diagram of a vehicle air conditioner according to a second embodiment of the present disclosure, showing a heater mode. [Figure 4] 4 is a schematic diagram illustrating a defrosting operation mode of the vehicle air conditioner of FIG. 3. FIG. [Figure 5]5 is a schematic diagram showing a case where the temperature of the battery is controlled in the heater mode of FIG. 4. FIG. [Figure 6] 5 is a schematic diagram showing a first modification of the defrosting operation mode of FIG. 4. FIG. [Figure 7] 5 is a schematic diagram showing a second modification of the defrosting operation mode of FIG. 4. FIG. [Figure 8] 5 is a schematic diagram showing a third modification of the defrosting operation mode of FIG. 4. FIG. [Figure 9] FIG. 5 is a schematic diagram showing a fourth modification of the defrosting operation mode of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [First embodiment] Hereinafter, a first embodiment of the present disclosure will be described with reference to FIG. 1 shows an outline of a vehicle air conditioner (temperature control system) 1 according to this embodiment. The vehicle air conditioner 1 includes a refrigerant circuit 3, a hot water circuit (heat medium circuit) 5, and a cold water circuit (heat medium circuit) 7.

[0011] The refrigerant circuit 3 includes a compressor 10 that compresses the refrigerant, a condenser (high-pressure side heat exchanger) 11 that condenses (or releases heat from) the refrigerant compressed by the compressor 10, an expansion valve 12 that expands the refrigerant condensed by the condenser 11, and an evaporator (low-pressure side heat exchanger) 13 that evaporates the refrigerant expanded by the expansion valve 12, forming a refrigeration cycle. For example, a scroll compressor or a rotary compressor is used as the compressor 10. The operation of the refrigerant circuit 3 is controlled by a control unit (not shown).

[0012] The hot water circuit 5 is a flow path that mainly supplies hot water (heat medium, coolant) heated in the condenser 11 to the indoor heat exchanger (temperature control device) 18, and returns the hot water that flows out from the indoor heat exchanger 18 to the condenser 11.

[0013] In the hot water circuit 5, a first four-way valve 20 is connected to a hot water outlet pipe 19 through which hot water flows out from the condenser 11. Connected to the first four-way valve 20 are a cold water outlet pipe 21 through which cold water flows out from the evaporator 13 in the cold water circuit 7, an outdoor heat exchanger inlet pipe 24 provided upstream of the outdoor heat exchanger 22, and an outdoor heat exchanger bypass pipe 26 that bypasses the outdoor heat exchanger 22. The opening and closing of the first four-way valve 20 is controlled by a control unit.

[0014] The outdoor heat exchanger 22 exchanges heat between a heat medium such as water and outside air. A second four-way valve 28 is connected to an outdoor heat exchange outlet pipe 27 through which the heat medium flows out of the outdoor heat exchanger 22. The second four-way valve 28 is connected to an outdoor heat exchange bypass pipe 26. That is, the outdoor heat exchange bypass pipe 26 connects the first four-way valve 20 and the second four-way valve 28.

[0015] The second four-way valve 28 is connected to a hot water pump inlet pipe 31 connected to the inlet side of the hot water pump 30 and a cold water pump inlet pipe 33 connected to the inlet side of the cold water pump 32. The opening and closing of the second four-way valve 28 is controlled by a control unit. The rotation speeds, i.e., the flow rates, of the hot water pump 30 and the cold water pump 32 are controlled by the control unit.

[0016] Hot water discharge piping 35, through which hot water is discharged from the hot water pump 30, is connected to a third four-way valve 37. Cold water discharge piping 36, through which cold water is discharged from the cold water pump 32, is connected to the third four-way valve 37. A four-way valve connection piping 40, which is connected to a fourth four-way valve 39, and an indoor heat exchanger inlet piping 41, which is connected to the inlet side of the indoor heat exchanger 18, are connected to the third four-way valve 37. The opening and closing of the third four-way valve 37 and the fourth four-way valve 39 is controlled by a control unit.

[0017] An indoor heat exchange outlet pipe 42 connected to the outlet side of the indoor heat exchanger 18 is connected to a fourth four-way valve 39. The fourth four-way valve 39 is connected to a hot water return pipe 44 that returns hot water to the condenser 11 and a cold water return pipe 45 that returns cold water to the evaporator 13.

[0018] A heat medium bypass pipe 47 is provided between the hot water pump inlet pipe 31 on the upstream side of the hot water pump 30 and the chilled water pump inlet pipe 33 on the upstream side of the chilled water pump 32. The heat medium bypass pipe 47 allows hot water to flow from the hot water circuit 5 to the chilled water circuit 7, or allows chilled water to flow from the chilled water circuit 7 to the hot water circuit 5. A reserve tank 48 that stores hot water or chilled water is provided in the heat medium bypass pipe 47.

[0019] The control unit is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and computer-readable storage media. A series of processes for realizing various functions is stored in, for example, a storage medium in the form of a program. The CPU reads this program into RAM and executes information processing and arithmetic operations to realize various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0020] Next, the operation of the vehicle air conditioner 1 having the above-described configuration in the heater mode and defrosting operation mode will be described. <Heater mode> The heater mode is shown in Figure 1. The heater mode is used when the outdoor temperature is low, such as in winter, and sufficient heat absorption from the outdoor heat exchanger 22 cannot be expected even when heating operation is performed. In the heater mode, the cold water flowing out of the evaporator 13 is not guided to the outdoor heat exchanger 22, but is instead guided through the outdoor heat exchange bypass piping 26.

[0021] In addition, the heater mode in FIG. 1 is operated by the hot water pump 30, and the cold water pump 32 is stopped. Alternatively, the hot water pump 30 may be stopped and the cold water pump 32 may be operated instead. It may also be operated by a hot water pump 30 and a cold water pump 32 .

[0022] In the figure, the flow paths indicated by solid lines in the hot water circuit 5 and the cold water circuit 7 indicate that the heat medium does not flow. The dashed lines indicate that cold water flows, and the two-dot chain lines indicate that hot water flows.

[0023] In the refrigerant circuit 3, the refrigerant compressed by the compressor 10 is sent to the condenser 11 and condensed. When the refrigerant condenses, the latent heat of condensation is imparted to hot water, which is a heat medium circulating through the condenser 11, to heat it.

[0024] The liquid refrigerant leaving the condenser 11 is decompressed by the expansion valve 12 and is led to the evaporator 13. In the evaporator 13, the refrigerant evaporates, and the latent heat of evaporation is taken from the chilled water, which is a heat medium circulating through the evaporator 13, and the chilled water is cooled.

[0025] In the hot water circuit 5, hot water heated in the condenser 11 passes through the first four-way valve 20 and is guided to the second four-way valve 28 via the outdoor heat exchange bypass piping 26. This prevents the heat medium from flowing through the outdoor heat exchanger 22. At the first four-way valve 20, cold water cooled in the evaporator 13 joins the hot water.

[0026] The hot water that leaves the second four-way valve 28 is guided by the hot water pump 30 through the third four-way valve 37 to the interior heat exchanger 18. The interior heat exchanger 18 heats the air in the vehicle cabin by exchanging heat with the air.

[0027] The hot water leaving the indoor heat exchanger 18 is led to the fourth four-way valve 39, and a portion of the hot water is returned to the condenser 11 through the hot water return pipe 44, and the remaining hot water is returned to the evaporator 13 through the cold water return pipe 45.

[0028] In the chilled water circuit 7, the chilled water cooled in the evaporator 13 is guided to the first four-way valve 20 and merges with the hot water. The subsequent flow up to the fourth four-way valve 39 is the same as that of the hot water described above. At the fourth four-way valve 39, the hot water that has flowed to the chilled water return pipe 45 is returned to the evaporator 13.

[0029] <Defrosting operation mode> Next, the defrosting operation mode will be described with reference to FIG. In the heat pump mode, the cold water flowing out of the evaporator 13 is guided to the outdoor heat exchanger 22 and exchanges heat with the outdoor air. In this way, in the heat pump mode, cold water is guided to the outdoor heat exchanger 22, and frosting occurs when the cold water temperature falls below 0°C. Therefore, the control unit determines whether frost has formed on the outdoor heat exchanger 22 using a frost sensor or the like provided in the outdoor heat exchanger 22, and then switches to the defrosting operation mode via the heater mode described above.

[0030] In the defrosting operation mode of FIG. 2, similarly to the heater mode of FIG. 1, the hot water pump 30 is operated, and the cold water pump 32 is stopped. Alternatively, the hot water pump 30 may be stopped and the cold water pump 32 may be operated instead. It may also be operated by a hot water pump 30 and a cold water pump 32 .

[0031] In the defrosting operation mode, the first four-way valve 20 is switched to connect the hot water outlet pipe 19 to the outdoor heat exchanger bypass pipe 26, and also connect the cold water outlet pipe 21 to the outdoor heat exchanger inlet pipe 24. Therefore, through the first four-way valve 20, hot water flows bypassing the outdoor heat exchanger 22, and only cold water flows to the outdoor heat exchanger 22.

[0032] The cold water is merged with the hot water at the second four-way valve 28. The hot water merged with the cold water at the second four-way valve 28 is guided to the indoor heat exchanger 18 by the hot water pump 30, as in the heater mode. The hot water is distributed to the hot water return pipe 44 and the cold water return pipe 45 by the fourth four-way valve 39, as in the heater mode.

[0033] The above-described embodiment has the following advantages. When the defrosting operation mode is performed, defrosting is performed by guiding cold water from the evaporator 13 to the outdoor heat exchanger 22. In this way, cold water is guided from the evaporator 13 instead of hot water from the condenser 11, so that relatively high temperature heat can be prevented from being released from the outdoor heat exchanger 22 to the outside air via the hot water.

[0034] [Second embodiment] Next, a second embodiment of the present disclosure will be described with reference to FIG. The vehicle air conditioner 1 in Fig. 3 has a different configuration of the heat medium circuit from that of the first embodiment. In the following description, configurations that differ from those of the first embodiment will be described, and the same configurations will be assigned the same reference numerals and descriptions thereof will be omitted.

[0035] 3, the hot water circuit 5 includes a hot water pump 30 connected to the hot water outlet pipe 19. The cold water circuit 7 includes a cold water pump 32 connected to the cold water outlet pipe 21.

[0036] The indoor heat exchanger 18, the outdoor heat exchanger 22, and the battery (secondary battery) heat exchanger 50 are connected to the hot water discharge pipe 35 connected to the hot water pump 30 and the cold water discharge pipe 36 connected to the cold water pump 32. The battery heat exchanger 50 regulates the temperature of the battery. The battery stores electricity from an external power source, regenerated energy during driving, etc. The electricity stored in the battery is consumed for driving power, vehicle control, air conditioning power, etc.

[0037] An indoor heat exchanger upstream three-way valve 52a is provided on the indoor heat exchanger inlet pipe 41 upstream of the indoor heat exchanger 18, and an indoor heat exchanger downstream three-way valve 52b is provided on the indoor heat exchanger outlet pipe 42 downstream of the indoor heat exchanger 18. The opening degree of the indoor heat exchanger upstream three-way valve 52a is controlled by a control unit (not shown), allowing hot water from the hot water pump 30 and cold water from the cold water pump 32 to flow to the indoor heat exchanger 18. The indoor heat exchanger downstream three-way valve 52b is controlled by a control unit (not shown), allowing hot water or cold water flowing out of the indoor heat exchanger 18 to flow to the hot water return pipe 44 and the cold water return pipe 45. The opening degrees of the indoor heat exchanger upstream three-way valve 52a and the indoor heat exchanger downstream three-way valve 52b are controlled synchronously by a single actuator. Note that the present disclosure is not limited to the above-described three-way valves, and other three-way valves or two-way valves may be combined.

[0038] An outdoor heat exchanger upstream three-way valve 53a is provided in the outdoor heat exchanger inlet pipe 24 upstream of the outdoor heat exchanger 22, and an outdoor heat exchanger downstream three-way valve 53b is provided in the outdoor heat exchanger outlet pipe 27 downstream of the outdoor heat exchanger 22. The opening degree of the outdoor heat exchanger upstream three-way valve 53a is controlled by a control unit (not shown), allowing hot water from the hot water pump 30 and cold water from the cold water pump 32 to flow to the outdoor heat exchanger 22. The outdoor heat exchanger downstream three-way valve 53b is controlled by a control unit (not shown), allowing hot water or cold water flowing out of the outdoor heat exchanger 22 to flow to the hot water return pipe 44 and the cold water return pipe 45. The opening degrees of the outdoor heat exchanger upstream three-way valve 53a and the outdoor heat exchanger downstream three-way valve 53b are controlled synchronously by a single actuator. Note that the present disclosure is not limited to the above-described three-way valves, and other three-way valves or two-way valves may be combined.

[0039] A battery heat exchanger upstream three-way valve 56a is provided in the battery heat exchanger inlet pipe 54 upstream of the battery heat exchanger 50, and a battery heat exchanger downstream three-way valve 56b is provided in the battery heat exchanger outlet pipe 55 downstream of the battery heat exchanger 50. The opening degree of the battery heat exchanger upstream three-way valve 56a is controlled by a control unit (not shown), allowing hot water from the hot water pump 30 and cold water from the cold water pump 32 to flow to the battery heat exchanger 50. The battery heat exchanger downstream three-way valve 56b is controlled by a control unit (not shown), allowing hot water or cold water flowing out of the battery heat exchanger 50 to flow to the hot water return pipe 44 and the cold water return pipe 45. The opening degrees of the battery heat exchanger upstream three-way valve 56a and the battery heat exchanger downstream three-way valve 56b are controlled synchronously by a single actuator. Note that the present disclosure is not limited to the above-described three-way valve, and other three-way valves or two-way valves may be combined.

[0040] A battery water pump 58, whose operation is controlled by the control unit, is provided on the battery heat exchanger inlet pipe 54. A connection pipe 59 is provided upstream of the battery water pump 58, connecting the battery heat exchanger inlet pipe 54 and the battery heat exchanger outlet pipe 55. A flow control valve (not shown) is provided on the connection pipe 59, and is used to regulate the temperature of the battery.

[0041] Next, the operation of the vehicle air conditioner 1 having the above-described configuration in the heater mode and defrosting operation mode will be described. <Heater mode> The heater mode is shown in Figure 3. In the figure, the flow paths shown by solid lines in the hot water circuit 5 and the cold water circuit 7 indicate that no heat medium flows. The dashed lines indicate that cold water flows, and the two-dot chain lines indicate that hot water flows.

[0042] In the heater mode, as in the first embodiment, the cold water flowing out from the evaporator 13 is not led to the outdoor heat exchanger 22. In this embodiment, the cold water is mixed with hot water in the indoor heat exchanger upstream three-way valve 52a and is flowed to the indoor heat exchanger 18.

[0043] The hot water flowing out of the indoor heat exchanger 18 is distributed by the indoor heat exchanger downstream three-way valve 52b to the hot water return pipe 44 and the cold water return pipe 45, and is returned to the condenser 11 and the evaporator 13, respectively.

[0044] Also, in the heater mode of FIG. 3, hot water is transported by the hot water pump 30 and cold water is transported by the cold water pump 32.

[0045] The battery heat exchanger upstream three-way valve 56a and the battery heat exchanger downstream three-way valve 56b are fully closed to prevent the heat medium (hot water or cold water) from flowing through the battery heat exchanger 50.

[0046] <Defrosting operation mode> Next, the defrosting operation mode will be explained using Fig. 4. In Fig. 4, as in Fig. 3, solid lines indicate that the heat medium does not flow, dashed lines indicate that cold water flows, and two-dot chain lines indicate that hot water flows. Also, one-dot chain lines indicate that medium-temperature water (water with a temperature between hot water and cold water) flows. In the heater mode described above, if the control unit determines that frost has formed on the outdoor heat exchanger 22, the operation mode is switched to the defrosting operation mode.

[0047] As shown in Fig. 4, the outdoor heat exchanger upstream three-way valve 53a is switched so that the cold water guided from the cold water discharge pipe 36 flows in two directions: the hot water discharge pipe 35 and the outdoor heat exchanger inlet pipe 24. As a result, part of the cold water merges with the hot water flowing in the hot water discharge pipe 35, and the rest of the cold water is guided to the outdoor heat exchanger 22.

[0048] The indoor heat exchanger upstream three-way valve 52a is switched to allow the hot water introduced from the hot water discharge pipe 35 to flow and to prevent the cold water introduced from the cold water discharge pipe 36 from flowing. As a result, only the hot water is introduced to the indoor heat exchanger 18.

[0049] The indoor heat exchanger downstream three-way valve 52b is switched so that the hot water flowing out of the indoor heat exchanger 18 does not flow into the cold water return pipe 45 but flows only into the hot water return pipe 44.

[0050] By switching the outdoor heat exchanger downstream three-way valve 53b, the cold water flowing out of the outdoor heat exchanger 22 merges with the hot water guided from the indoor heat exchanger downstream three-way valve 52b to become medium-temperature water, which is then guided to the cold water return pipe 45.

[0051] As in the heater mode, the battery heat exchanger upstream three-way valve 56a and the battery heat exchanger downstream three-way valve 56b are fully closed to prevent the heat medium (hot water or cold water) from flowing through the battery heat exchanger 50.

[0052] The above-described embodiment has the following advantages. When the defrosting operation mode is performed, defrosting is performed by guiding cold water from the evaporator 13 to the outdoor heat exchanger 22. In this way, cold water is guided from the evaporator 13 instead of hot water from the condenser 11, so that relatively high temperature heat can be prevented from being released from the outdoor heat exchanger 22 to the outside air via the hot water.

[0053] In the heater mode shown in Fig. 3, control is performed so that the heat medium is not flowed to the battery heat exchanger 50. However, as shown in Fig. 5, for example, in the heater mode, the heat medium may be flowed to the battery heat exchanger 50 to heat the battery. This is to allow the battery to exhibit the desired performance. Specifically, the three-way valve 56a upstream of the battery heat exchanger is switched to flow hot water to the battery heat exchanger 50. The medium-temperature water flowing out of the battery heat exchanger 50 is guided to the hot water return pipe 44 by switching the three-way valve 56b downstream of the battery heat exchanger.

[0054] Since the battery has a certain heat capacity, it can operate without temperature control within a certain time, such as the defrosting period. Therefore, in the defrosting operation mode, as shown in Figure 4, the battery heat exchanger upstream three-way valve 56a and the battery heat exchanger downstream three-way valve 56b are fully closed to prevent the heat medium from flowing through the battery heat exchanger 50. This makes it possible to suppress heat dissipation to the battery and to prevent a decrease in the heating capacity of the indoor heat exchanger 18.

[0055] In addition, the present embodiment can combine the following operations.

[0056] <Increased heating capacity operation> Before switching from the heater mode to the defrosting operation mode, a heating capacity increase operation may be performed to increase the heating capacity of the indoor heat exchanger 18.

[0057] When the operation mode is switched to the defrosting operation mode, the cold water defrosted by the outdoor heat exchanger 22 flows to the evaporator 13, which may reduce the low pressure in the refrigerant circuit and reduce the heating capacity in the heater mode. Therefore, before switching from the heater mode to the defrosting operation mode, a heating capacity increase operation is performed to increase the heating capacity of the indoor heat exchanger 18. This makes it possible to prevent a reduction in heating capacity when switching to the defrosting operation mode.

[0058] Specifically, the control unit increases the rotation speed of the compressor 10 and / or increases the flow rate of the heat medium flowing to the evaporator 13. The flow rate of the heat medium is increased by controlling the indoor heat exchanger downstream three-way valve 52b.

[0059] The heating capacity can be increased by increasing the rotation speed of the compressor 10 to increase the high-pressure refrigerant. Also, the flow rate of the heat medium flowing to the evaporator 13 can be increased to raise the temperature of the evaporator 13 and increase the low-pressure refrigerant, thereby increasing the heating capacity.

[0060] The above-described heating capacity increased operation can also be applied to the first embodiment.

[0061] <Low pressure control> In the defrosting operation mode, the control unit may control the refrigerant pressure of the evaporator 13 so that the temperature of the cold water flowing out from the evaporator 13 is 5°C or higher.

[0062] By controlling the low pressure of the refrigerant so that the temperature of the chilled water flowing out of the evaporator 13 is 5°C or higher, defrosting can be effectively performed in the outdoor heat exchanger 22. The pressure of the low pressure refrigerant is controlled by controlling the rotation speed of the compressor and the opening of the expansion valve.

[0063] The above-described low pressure control can also be applied to the first embodiment.

[0064] <Gradual increase control of heat transfer medium flow rate> In the defrosting operation mode, the control unit may perform control so as to gradually increase the flow rate of cold water flowing through the outdoor heat exchanger 22.

[0065] By gradually increasing the flow rate of chilled water in the defrosting operation mode, the temperature change in the outdoor heat exchanger 22 is made gentler, and heat shock is avoided, thereby preventing damage to the outdoor heat exchanger 22.

[0066] The above-described heat medium flow rate gradual increase control can also be applied to the first embodiment.

[0067] <Modification 1 of the heat medium circuit in the defrosting operation mode> As shown in FIG. 6, the heat medium circuit in the defrosting operation mode can be modified as follows.

[0068] In the defrosting operation mode shown in Fig. 4, the indoor heat exchanger upstream three-way valve 52a is switched so that only hot water flows to the indoor heat exchanger 18. In contrast to this, as shown in Fig. 6, the indoor heat exchanger upstream three-way valve 52a may be switched so that hot water and cold water are merged and directed to the indoor heat exchanger 18. Also, the outdoor heat exchanger upstream three-way valve 53a may be switched so that cold water flows only to the outdoor heat exchanger 22 and so that cold water does not merge into the hot water discharge pipe 35.

[0069] <Modification 2 of the heat medium circuit in the defrosting operation mode> As shown in FIG. 7, in the defrosting operation mode, medium-temperature water may be made to flow to the outdoor heat exchanger 22.

[0070] The indoor heat exchanger upstream three-way valve 52a is switched to distribute the hot water guided from the hot water discharge piping 35 to the indoor heat exchanger inlet piping 41 and the chilled water return piping 45. Only the hot water that flows into the indoor heat exchanger inlet piping 41 is guided to the indoor heat exchanger 18. The hot water guided to the chilled water return piping 45 merges with the chilled water upstream of the outdoor heat exchanger upstream three-way valve 53a, and is guided to the outdoor heat exchanger 22 via the outdoor heat exchanger upstream three-way valve 53a. As a result, medium-temperature water (dashed line) that is a mixture of hot water and chilled water is guided to the outdoor heat exchanger 22.

[0071] The outdoor heat exchange downstream three-way valve 53 b distributes the medium-temperature water flowing out from the outdoor heat exchanger 22 to the hot water return pipe 44 and the cold water return pipe 45 .

[0072] Furthermore, the configuration in which medium-temperature water is flowed to the outdoor heat exchanger 22 as described above may be used in combination with the configuration in which cold water is flowed to the outdoor heat exchanger 22 as shown in Fig. 4 etc. Specifically, in the defrosting operation mode, cold water is flowed to the outdoor heat exchanger 22 as shown in Fig. 4 etc., and then medium-temperature water is flowed as shown in Fig. 7. This makes it possible to shorten the defrosting period by using medium-temperature water while avoiding heat shock in the outdoor heat exchanger 22.

[0073] <Modification 3 of the heat medium circuit in the defrosting operation mode> Instead of the configuration of FIG. 7, as shown in FIG. 8, medium-temperature water may be made to flow to the outdoor heat exchanger 22 in the defrosting operation mode. In Figure 7, hot water is guided from the indoor heat exchanger upstream three-way valve 52a to the outdoor heat exchanger upstream three-way valve 53a, but as shown in Figure 8, hot water may also be guided from the hot water discharge pipe 35 to the outdoor heat exchanger upstream three-way valve 53a.

[0074] <Modification 4 of the heat medium circuit in the defrosting operation mode> As shown in FIG. 9, a configuration in which hot water flows through the outdoor heat exchanger 22 may be combined.

[0075] The outdoor heat exchanger upstream three-way valve 53a is switched to allow the hot water to flow from the hot water discharge pipe 35 to the outdoor heat exchanger inlet pipe 24. As a result, only the hot water is guided to the outdoor heat exchanger 22.

[0076] The configuration in which only hot water is guided to the outdoor heat exchanger 22 is performed after the configuration in which cold water is guided to the outdoor heat exchanger 22 as shown in Fig. 4 etc. and / or the configuration in which medium-temperature water is flowed to the outdoor heat exchanger 22 as shown in Fig. 7 etc. This makes it possible to shorten the defrosting period using hot water while avoiding heat shock in the outdoor heat exchanger 22.

[0077] The temperature adjustment system and the control method thereof described in each of the above-described embodiments can be understood, for example, as follows.

[0078] A temperature control system (1) according to a first aspect of the present disclosure includes a refrigerant circuit (3) having a compressor (10) that compresses a refrigerant, a high-pressure side heat exchanger (11) that dissipates heat from the refrigerant compressed by the compressor, an expansion valve (12) that expands the refrigerant that has dissipated heat in the high-pressure side heat exchanger, and a low-pressure side heat exchanger (13) that evaporates the refrigerant expanded by the expansion valve, heat medium circuits (5, 7) through which a heat medium that exchanges heat with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger circulates, and a control unit that controls the refrigerant circuit and the heat medium circuit, and the heat medium circuit includes a temperature control device (1) that exchanges heat between the heat medium and a temperature control target. and an outdoor heat exchanger (22) that exchanges heat between the heat medium and outdoor air, and the control unit has a heater mode in which the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature adjustment device and the heat medium flowing out of the low-pressure side heat exchanger is not guided to the outdoor heat exchanger, a heat pump mode in which the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature adjustment device and the heat medium flowing out of the low-pressure side heat exchanger is guided to the outdoor heat exchanger, and a defrosting operation mode in which, when frost forms on the outdoor heat exchanger in the heat pump mode, the heat medium is guided from the low-pressure side heat exchanger to the outdoor heat exchanger.

[0079] In the heat pump mode, the heat medium flowing out of the low-pressure heat exchanger is guided to the outdoor heat exchanger, where it exchanges heat with the outdoor air. In this way, in the heater mode, the heat medium is guided to the outdoor heat exchanger, and frosting occurs when the heat medium temperature drops below 0°C. Therefore, when frost forms on the outdoor heat exchanger, the heat medium is guided from the low-pressure heat exchanger to the outdoor heat exchanger to defrost it. In this way, the heat medium is guided from the low-pressure heat exchanger, rather than from the high-pressure heat exchanger, which prevents relatively high-temperature heat from being released from the outdoor heat exchanger to the outdoor air via the heat medium.

[0080] In the temperature control system according to the second aspect of the present disclosure, in the first aspect, the control unit performs a heating capacity increase operation to increase the heating capacity of the temperature control device before switching from the heater mode to the defrosting operation mode.

[0081] When the system switches to the defrosting operation mode, the heat medium defrosted in the outdoor heat exchanger flows to the low-pressure heat exchanger, which reduces the low pressure in the refrigerant circuit and may reduce the heating capacity in the heater mode. Therefore, before switching from the heater mode to the defrosting operation mode, a heating capacity increase operation is performed to increase the heating capacity of the temperature control device. This makes it possible to prevent a reduction in heating capacity when switching to the defrosting operation mode.

[0082] In the temperature control system according to the third aspect of the present disclosure, in the second aspect, the control unit increases the rotation speed of the compressor and / or increases the flow rate of the heat medium flowing to the low-pressure side heat exchanger during the increased heating capacity operation.

[0083] The rotation speed of the compressor is increased to increase the high-pressure pressure of the refrigerant, thereby increasing the heating capacity. Also, the flow rate of the heat medium flowing to the low-pressure heat exchanger is increased to raise the temperature of the low-pressure heat exchanger and increase the low-pressure pressure of the refrigerant, thereby increasing the heating capacity.

[0084] In the temperature control system according to a fourth aspect of the present disclosure, in any one of the first to third aspects, in the defrosting operation mode, a low-temperature heat medium flowing out from the low-pressure side heat exchanger is guided to the outdoor heat exchanger, or a medium-temperature heat medium obtained by mixing the low-temperature heat medium flowing out from the low-pressure side heat exchanger and the high-temperature heat medium flowing out from the high-pressure side heat exchanger is guided to the outdoor heat exchanger.

[0085] In the defrosting operation mode, the low-temperature heat medium flowing out from the low-pressure side heat exchanger may be directly introduced to the outdoor heat exchanger, or a medium-temperature heat medium obtained by mixing the low-temperature heat medium flowing out from the low-pressure side heat exchanger and the high-temperature heat medium flowing out from the high-pressure side heat exchanger may be introduced. Compared to using the high-temperature heat medium flowing out from the high-pressure side heat exchanger directly for the defrosting operation, the heat loss to the outside air is smaller.

[0086] In a temperature control system according to a fifth aspect of the present disclosure, in any one of the first to fourth aspects, the control unit controls the refrigerant pressure of the low-pressure side heat exchanger in the defrosting operation mode so that the temperature of the low-temperature heat medium flowing out of the low-pressure side heat exchanger is 5°C or higher.

[0087] The low pressure of the refrigerant is controlled so that the temperature of the low-temperature heat medium flowing out of the low-pressure side heat exchanger is 5°C or higher. This allows for effective defrosting in the outdoor heat exchanger.

[0088] A temperature adjustment system according to a sixth aspect of the present disclosure is in any one of the first to fifth aspects, wherein the heat medium circuit includes a heat exchanger (50) for a secondary battery that maintains a predetermined temperature of the secondary battery by a heat medium, and the control unit stops the supply of the heat medium to the heat exchanger for the secondary battery in the defrosting operation mode.

[0089] The temperature of the secondary battery is controlled within a predetermined operating temperature range. However, because the secondary battery has a certain heat capacity, it can operate without temperature control within a predetermined time, such as the defrosting period. Therefore, in the defrosting operation mode, the heat medium is not passed through the secondary battery heat exchanger. This reduces heat dissipation to the secondary battery and prevents a decrease in the heating capacity of the temperature control device.

[0090] In a temperature control system according to a seventh aspect of the present disclosure, in any one of the first to sixth aspects, the control unit controls the heat medium flow rate flowing through the outdoor heat exchanger to gradually increase in the defrosting operation mode.

[0091] In the defrosting operation mode, the heat transfer medium flow rate is gradually increased, which makes it possible to prevent damage to the outdoor heat exchanger by slowing down the temperature change in the outdoor heat exchanger and avoiding heat shock.

[0092] In a temperature control system according to an eighth aspect of the present disclosure, in any one of the first to seventh aspects, the control unit, in the defrosting operation mode, guides to the outdoor heat exchanger a low-temperature heat medium flowing out from the low-pressure side heat exchanger, and then guides a medium-temperature heat medium obtained by mixing the low-temperature heat medium flowing out from the low-pressure side heat exchanger and the high-temperature heat medium flowing out from the high-pressure side heat exchanger.

[0093] In the defrosting operation mode, the low-temperature heat medium is first circulated through the outdoor heat exchanger, and then the medium-temperature heat medium is circulated through the outdoor heat exchanger. This makes it possible to shorten the defrosting period using the medium-temperature heat medium while avoiding heat shock in the outdoor heat exchanger.

[0094] In a temperature control system according to a ninth aspect of the present disclosure, in any of the first to seventh aspects, the control unit, in the defrosting operation mode, guides, to the outdoor heat exchanger, a low-temperature heat medium flowing out of the low-pressure side heat exchanger and / or a medium-temperature heat medium obtained by mixing the low-temperature heat medium flowing out of the low-pressure side heat exchanger and the high-temperature heat medium flowing out of the high-pressure side heat exchanger, and then guides the high-temperature heat medium.

[0095] In the defrosting operation mode, a low-temperature heat medium and / or a medium-temperature heat medium is first circulated through the outdoor heat exchanger, and then a high-temperature heat medium is circulated through the outdoor heat exchanger. This makes it possible to shorten the defrosting period by using the high-temperature heat medium while avoiding heat shock in the outdoor heat exchanger.

[0096] A control method for a temperature adjustment system according to a first aspect of the present disclosure is a control method for a temperature adjustment system including a refrigerant circuit having a compressor that compresses a refrigerant, a high-pressure side heat exchanger that dissipates heat from the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant that has dissipated heat in the high-pressure side heat exchanger, and a low-pressure side heat exchanger that evaporates the refrigerant expanded in the expansion valve, and a heat medium circuit in which a heat medium that exchanges heat with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger circulates, the heat medium circuit including a temperature adjustment device that exchanges heat between the heat medium and a temperature adjustment target, and an outdoor heat exchanger that exchanges heat between the heat medium and outdoor air, a heater mode in which the heat medium discharged from the temperature control device is guided to the temperature control device and the heat medium flowing out from the temperature control device is guided to the low-pressure side heat exchanger without being guided to the outdoor heat exchanger; a heat pump mode in which the heat medium flowing out from the high-pressure side heat exchanger is guided to the temperature control device and the heat medium flowing out from the low-pressure side heat exchanger is guided to the outdoor heat exchanger; and a defrosting operation mode in which, if frost forms on the outdoor heat exchanger in the heat pump mode, some or all of the heat medium from the low-pressure side heat exchanger is guided to the outdoor heat exchanger and some or all of the heat medium from the high-pressure side heat exchanger is guided to the temperature control device. [Explanation of symbols]

[0097] 1. Vehicle air conditioning system (temperature control system) 3 Refrigerant circuit 5 Hot water circuit (heat medium circuit) 7 Chilled water circuit (heat medium circuit) 10 Compressor 11 Condenser (high pressure side heat exchanger) 12 Expansion valve 13 Evaporator (low-pressure side heat exchanger) 18 Indoor heat exchanger (temperature control equipment) 19 Hot water outlet piping 20 First four-way valve 21 Chilled water outlet piping 22 Outdoor heat exchanger 24 Outdoor heat exchanger inlet piping 26 Outdoor heat exchanger bypass piping 27 Outdoor heat exchanger outlet piping 28 Second four-way valve 30 Hot water pump 31 Hot water pump inlet piping 32 Chilled water pump 33 Chilled water pump inlet piping 35 Hot water discharge piping 36 Cold water discharge piping 37 Third four-way valve 39 Fourth four-way valve 40 Four-way valve connection piping 41 Indoor heat exchanger inlet piping 42 Indoor heat exchanger outlet piping 44 Hot water return piping 45 Chilled water return piping 47 Heat medium bypass piping 48 Reserve Tank 50 Heat exchanger for battery (secondary battery) 52a Indoor heat exchanger upstream three-way valve 52b Indoor heat exchanger downstream three-way valve 53a Outdoor heat exchanger upstream three-way valve 53b Outdoor heat exchanger downstream three-way valve 54 Battery heat exchanger inlet piping 55 Battery heat exchanger outlet piping 56a Battery heat exchanger upstream three-way valve 56b Battery heat exchanger downstream three-way valve 58 Battery water pump 59 Connecting piping

Claims

1. a refrigerant circuit including a compressor that compresses a refrigerant, a high-pressure side heat exchanger that dissipates heat from the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant that has dissipated heat in the high-pressure side heat exchanger, and a low-pressure side heat exchanger that evaporates the refrigerant expanded by the expansion valve; a heat medium circuit through which a heat medium circulates that exchanges heat with a refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger; a control unit that controls the refrigerant circuit and the heat medium circuit, The heat medium circuit includes a temperature control device that exchanges heat between the heat medium and a temperature control target, and an outdoor heat exchanger that exchanges heat between the heat medium and outdoor air, a heater mode in which the control unit guides the heat medium flowing out of the high-pressure side heat exchanger to the temperature adjustment device and does not guide the heat medium flowing out of the low-pressure side heat exchanger to the outdoor heat exchanger; a heat pump mode in which the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature adjustment device and the heat medium flowing out of the low-pressure side heat exchanger is guided to the outdoor heat exchanger; a defrosting operation mode in which, when frost forms on the outdoor heat exchanger in the heat pump mode, a part or all of the heat medium from the low-pressure side heat exchanger is guided to the outdoor heat exchanger, and a part or all of the heat medium from the high-pressure side heat exchanger is guided to the temperature adjustment device; and In the defrosting operation mode, the heat medium that has left the outdoor heat exchanger returns to the low-pressure side heat exchanger without passing through the high-pressure side heat exchanger.

2. The temperature adjustment system according to claim 1 , wherein the control unit performs a heating capacity increase operation to increase the heating capacity of the temperature adjustment device before switching from the heater mode to the defrosting operation mode.

3. The temperature control system according to claim 2 , wherein the control unit increases the rotation speed of the compressor and / or increases the flow rate of the heat medium flowing to the low-pressure side heat exchanger during the heating capacity increase operation.

4. 3. The temperature control system according to claim 1, wherein in the defrosting operation mode, a low-temperature heat medium flowing out from the low-pressure side heat exchanger is guided to the outdoor heat exchanger, or a medium-temperature heat medium obtained by mixing the low-temperature heat medium flowing out from the low-pressure side heat exchanger and the high-temperature heat medium flowing out from the high-pressure side heat exchanger is guided to the outdoor heat exchanger.

5. 3. The temperature adjustment system according to claim 1, wherein the control unit controls a refrigerant pressure in the low-pressure side heat exchanger in the defrosting operation mode so that a temperature of the low-temperature heat medium flowing out of the low-pressure side heat exchanger is 5°C or higher.

6. the heat medium circuit includes a secondary battery heat exchanger that maintains the secondary battery at a predetermined temperature by a heat medium; The temperature adjustment system according to claim 1 or 2, wherein the control unit stops supplying the heat medium to the secondary battery heat exchanger in the defrosting operation mode.

7. The temperature adjustment system according to claim 1 or 2, wherein the control unit controls the flow rate of the heat medium flowing through the outdoor heat exchanger to gradually increase in the defrosting operation mode.

8. 3. The temperature control system according to claim 1, wherein in the defrosting operation mode, the control unit guides the low-temperature heat medium flowing out of the low-pressure side heat exchanger to the outdoor heat exchanger, and then guides an intermediate-temperature heat medium obtained by mixing the low-temperature heat medium flowing out of the low-pressure side heat exchanger and the high-temperature heat medium flowing out of the high-pressure side heat exchanger to the outdoor heat exchanger.

9. 3. The temperature control system according to claim 1, wherein in the defrosting operation mode, the control unit guides, to the outdoor heat exchanger, a low-temperature heat medium flowing out from the low-pressure side heat exchanger and / or an intermediate-temperature heat medium obtained by mixing the low-temperature heat medium flowing out from the low-pressure side heat exchanger and the high-temperature heat medium flowing out from the high-pressure side heat exchanger, and then guides the high-temperature heat medium.

10. a refrigerant circuit including a compressor that compresses a refrigerant, a high-pressure side heat exchanger that dissipates heat from the refrigerant compressed by the compressor, an expansion valve that expands the refrigerant that has dissipated heat in the high-pressure side heat exchanger, and a low-pressure side heat exchanger that evaporates the refrigerant expanded by the expansion valve; a heat medium circuit through which a heat medium circulates that exchanges heat with a refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger; Equipped with The heat medium circuit is a temperature control system including a temperature control device that exchanges heat between a heat medium and a temperature control target, and an outdoor heat exchanger that exchanges heat between the heat medium and outdoor air, a heater mode in which the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the heat medium flowing out of the temperature control device is guided to the low-pressure side heat exchanger without being guided to the outdoor heat exchanger; a heat pump mode in which the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature adjustment device and the heat medium flowing out of the low-pressure side heat exchanger is guided to the outdoor heat exchanger; a defrosting operation mode in which, when frost forms on the outdoor heat exchanger in the heat pump mode, a part or all of the heat medium from the low-pressure side heat exchanger is guided to the outdoor heat exchanger, and a part or all of the heat medium from the high-pressure side heat exchanger is guided to the temperature adjustment device; and In the defrosting operation mode, the heat medium that has left the outdoor heat exchanger returns to the low-pressure side heat exchanger without passing through the high-pressure side heat exchanger.

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