Temperature control system and its control method

Abstract

Provide a temperature control system that can suppress as much as possible the decrease in heating capacity when switching from the heat pump mode to the heater mode. 【Solution means】The heat medium circuit includes an indoor heat exchanger 18 that exchanges heat between warm water and indoor air, and an outdoor heat exchanger 22 that exchanges heat between cold water and outside air. The control unit guides the warm water flowing out from the condenser 11 to the indoor heat exchanger 18, and at the same time guides the cold water flowing out from the evaporator 13 to the outdoor heat exchanger 22 in the heat pump mode, and mixes at least a part of the warm water flowing out from the condenser 11 and the cold water flowing out from the evaporator 13, and at the same time guides at least a part of the heat medium flowing out from the condenser 11 to the indoor heat exchanger 18, and guides the mixed cold and warm water to the condenser 11 and the evaporator 13 in the heater mode, and before switching from the heat pump mode to the heater mode, it has a first transition mode of mixing the warm water flowing through the indoor heat exchanger 18 with the cold water flowing through the outdoor heat exchanger 22.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a temperature control system for a vehicle having a heat pump mode and a heater mode. In the heat pump mode, heat is absorbed from the outside air by an outdoor heat exchanger, and heating is performed by an indoor heat exchanger. The heater mode is a mode in which heating is performed using a compressor as a heat source when the outside air temperature drops and the amount of heat absorbed from the outside air decreases, making it difficult to perform heating in the heat pump mode. In the heater mode, cold water cooled by an evaporator is mixed with warm water heated by a condenser and led to an indoor heat exchanger to perform heating, and the warm water that has exchanged heat in the indoor heat exchanger is returned to the condenser and the evaporator.

[0003] Patent Document 1 discloses switching from the heat pump mode to the heater mode based on the outside air temperature.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As a result of intensive studies by the present inventors, the following problems were found when switching from the heat pump mode to the heater mode. That is, when switching to the heater mode, the cold water cooled by the evaporator is mixed with the warm water heated by the condenser, so the temperature of the warm water flowing into the indoor heat exchanger temporarily drops. As a result, there is a risk that the heating capacity (heating ability) will decrease immediately after switching to the heater mode.

[0006] The present disclosure has been made in view of such circumstances, and an object thereof is to provide a temperature control system and a control method thereof that can suppress as much as possible a decrease in heating capacity when switching from a heat pump mode to a heater mode.

Means for Solving the Problems

[0007] A temperature control system according to an aspect of the present disclosure includes 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 refrigerant circuit having a low-pressure side heat exchanger that evaporates the refrigerant expanded by 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. The heat medium circuit includes a temperature control device that exchanges heat between the heat medium and the temperature control target, and an outdoor heat exchanger that exchanges heat between the heat medium and the outside air. The control unit has 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, a heater mode in which at least a part of the heat medium flowing out of the high-pressure side heat exchanger and at least a part of the heat medium flowing out of the low-pressure side heat exchanger are mixed, at least a part of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger, and a first transition mode in which the heat medium flowing through the temperature control device is mixed with the heat medium flowing through the outdoor heat exchanger before switching from the heat pump mode to the heater mode.

[0008] A temperature control system according to one aspect of the present disclosure includes 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 refrigerant circuit having a low-pressure side heat exchanger that evaporates the refrigerant expanded by 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. The heat medium circuit includes a temperature control device that exchanges heat between the heat medium and the object to be temperature-controlled, and an outdoor heat exchanger that exchanges heat between the heat medium and the outside air. The control unit has 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, a heater mode in which at least a part of the heat medium flowing out from the high-pressure side heat exchanger and at least a part of the heat medium flowing out from the low-pressure side heat exchanger are mixed, at least a part of the heat medium flowing out from the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger, and a second transition mode in which a part of the heat medium flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger.

[0009] A control method for a temperature control system according to an 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 by 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 includes a temperature control device that exchanges heat between the heat medium and the temperature control target, and an outdoor heat exchanger that exchanges heat between the heat medium and the outside air. The control method for the temperature control system includes 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, a heater mode in which at least a part of the heat medium flowing out of the high-pressure side heat exchanger and at least a part of the heat medium flowing out of the low-pressure side heat exchanger are mixed, at least a part of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger, and a first transition mode in which the heat medium flowing through the temperature control device is mixed with the heat medium flowing through the outdoor heat exchanger before switching from the heat pump mode to the heater mode.

[0010] A control method for a temperature control system according to an aspect of the present disclosure includes 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 refrigerant circuit having a low-pressure side heat exchanger that evaporates the refrigerant expanded by 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 includes a temperature control device that exchanges heat between the heat medium and the temperature control target, and an outdoor heat exchanger that exchanges heat between the heat medium and the outside air. A control method for a temperature control system, comprising: 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 at least a part of the heat medium flowing out of the high-pressure side heat exchanger and at least a part of the heat medium flowing out of the low-pressure side heat exchanger are mixed, and at least a part of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger. And a second transition mode in which a part of the heat medium flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger.

Effects of the Invention

[0011] It is possible to suppress as much as possible a decrease in heating capacity when switching from the heat pump mode to the heater mode.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. [First Embodiment] Hereinafter, the first embodiment of the present disclosure will be described with reference to FIG. 1. 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.

[0014] 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) 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, and constitutes a refrigeration cycle. As the compressor 10, for example, a scroll compressor or a rotary compressor is used. The operation of the refrigerant circuit 3 is controlled by a control unit (not shown).

[0015] The hot water circuit 5 mainly supplies the hot water (heat medium, coolant) heated by the condenser 11 to the indoor heat exchanger (temperature control device) 18, and is a flow path that returns the hot water flowing out from the indoor heat exchanger 18 to the condenser 11.

[0016] In the hot water circuit 5, a first four-way valve 20 is connected to a hot water outlet pipe 19 from which hot water flows out of the condenser 11. To the first four-way valve 20, a cold water outlet pipe 21 from which cold water flows out of the evaporator 13 in the cold water circuit 7, an outdoor heat exchange inlet pipe 24 provided on the upstream side of the outdoor heat exchanger 22, and an outdoor heat exchange bypass pipe 26 that bypasses the outdoor heat exchanger 22 are connected. The connection direction of the first four-way valve 20 is controlled by the control unit.

[0017] The outdoor heat exchanger 22 exchanges heat between a heat medium such as water and outside air (fluid). A second four-way valve 28 is connected to an outdoor heat exchange outlet pipe 27 from which the heat medium flows out of the outdoor heat exchanger 22. The outdoor heat exchange bypass pipe 26 is connected to the second four-way valve 28. That is, the outdoor heat exchange bypass pipe 26 connects the first four-way valve 20 and the second four-way valve 28.

[0018] To the second four-way valve 28, 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 are connected. The connection direction of the second four-way valve 28 is controlled by the control unit. The rotation speed, that is, the flow rate, of the hot water pump 30 and the cold water pump 32 is controlled by the control unit.

[0019] A hot water discharge pipe 35 from which hot water is discharged from the hot water pump 30 is connected to a third four-way valve 37. A cold water discharge pipe 36 from which cold water is discharged from the cold water pump 32 is connected to the third four-way valve 37. To the third four-way valve 37, a four-way valve connection pipe 40 connected to the fourth four-way valve 39 and an indoor heat exchange inlet pipe 41 connected to the inlet side of the indoor heat exchanger 18 are connected. The connection directions of the third four-way valve 37 and the fourth four-way valve 39 are controlled by the control unit.

[0020] The indoor heat exchange outlet pipe 42 connected to the outlet side of the indoor heat exchanger 18 is connected to the 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.

[0021] A heat medium bypass pipe 47 is provided between the hot water pump inlet pipe 31 upstream of the hot water pump 30 and the cold water pump inlet pipe 33 upstream of the cold water pump 32. Through the heat medium bypass pipe 47, hot water flows from the hot water circuit 5 to the cold water circuit 7, or cold water flows from the cold water circuit 7 to the hot water circuit 5. The heat medium bypass pipe 47 is provided with a reserve tank 48 for storing hot water or cold water.

[0022] The control unit is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium, etc. And a series of processes for realizing various functions are stored in a storage medium, etc. in the form of a program as an example. The CPU reads this program into the RAM, etc., and executes information processing and arithmetic processing, thereby realizing various functions. Note that the program may be in a form pre-installed in the ROM or other storage media, a form provided in a state stored in a computer-readable storage medium, a form distributed via wired or wireless communication means, etc. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, etc.

[0023] Next, the operations of each operation mode using the vehicle air conditioner 1 having the above configuration will be described. <Heat pump mode> The heat pump mode is shown in FIG. 1. The heat pump mode performs heating operation when the outside air temperature is low, such as in winter. In the heat pump mode, the outdoor heat exchanger 22 absorbs heat from the outside air, and the indoor heat exchanger 18 heats the indoor air.

[0024] In the hot water circuit 5 and the cold water circuit 7 (heat medium circuit), the broken line indicates the flow of cold water, the two-dot chain line indicates the flow of hot water, and the solid line indicates the non-flow of the heat medium (the same applies to the following figures).

[0025] 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 given to the hot water, which is the heat medium flowing through the condenser 11, for heating.

[0026] The liquid refrigerant that has exited the condenser 11 is depressurized by the expansion valve 12 and guided to the evaporator 13. In the evaporator 13, the refrigerant evaporates, and the latent heat of evaporation is taken from the cold water, which is the heat medium flowing through the evaporator 13, and the cold water is cooled.

[0027] The hot water is heated in the condenser 11 and then reaches the indoor heat exchanger 18 through the hot water outlet pipe 19, the first four-way valve 20, the outdoor heat exchange bypass pipe 26, the second four-way valve 28, the hot water pump inlet pipe 31, the hot water pump 30, the third four-way valve 37, and the indoor heat exchange inlet pipe 41. After heating the indoor air in the indoor heat exchanger 18, the hot water is returned to the condenser 11 through the indoor heat exchange outlet pipe 42, the fourth four-way valve 39, and the hot water return pipe 44.

[0028] The cold water is cooled in the evaporator 13 and then reaches the outdoor heat exchanger 22 through the cold water outlet pipe 21, the first four-way valve 20, and the outdoor heat exchange inlet pipe 24. After absorbing heat from the outside air in the outdoor heat exchanger 22, the cold water is returned to the evaporator 13 through the outdoor heat exchange outlet pipe 27, the second four-way valve 28, the cold water pump inlet pipe 33, the cold water pump 32, the cold water discharge pipe 36, the third four-way valve 37, the four-way valve connection pipe 40, the fourth four-way valve 39, and the cold water return pipe 45.

[0029] <First transition mode> Figure 2 shows the first transition mode. The first transition mode is performed before the second transition mode and the heater mode, which will be described later, according to the command of the control unit. The following only explains the operations that change with respect to the above-described heat pump mode.

[0030] The control unit controls the first four-way valve 20 to mix a part of the hot water led from the hot water outlet pipe 19 with the cold water passing through the cold water outlet pipe 21. By mixing a part of the hot water with the cold water, the cold water flowing through the outdoor heat exchange inlet pipe 24 becomes medium temperature. In each of the following figures, the four-way valve controlled to mix fluids is shown surrounded by a dashed circle. Also, the medium-temperature heat medium is indicated by a one-dot chain line.

[0031] The medium-temperature cold water absorbs heat in the outdoor heat exchanger 22, then passes through the cold water pump 32 and reaches the fourth four-way valve 39. At the fourth four-way valve 39, a part of the medium-temperature cold water is mixed with the hot water led from the indoor heat exchange outlet pipe 42 by the control unit. As a result, the flow rate of the hot water supplied from the hot water circuit 5 to the cold water circuit 7 at the first four-way valve 20 is recovered to the hot water circuit 5 at the fourth four-way valve 39, and the balance of the heat media circulating in each of the hot water circuit 5 and the cold water circuit 7 is achieved.

[0032] The hot water after being mixed at the fourth four-way valve 39 is returned to the condenser 11 through the hot water return pipe 44.

[0033] The remaining part of the medium-temperature cold water is returned from the fourth four-way valve 39 to the evaporator 13 through the cold water return pipe 45. By returning the medium-temperature cold water to the evaporator 13 in this way, the temperature of the cold water flowing out of the evaporator 13 will rise compared to when in the heat pump mode.

[0034] <Second transition mode> Figure 3 shows the second transition mode. The second transition mode is performed after the first transition mode and before the heater mode to be described later according to the command of the control unit. The following only explains the operations that are changed compared to the above-described first transition mode.

[0035] The control unit controls the first four-way valve 20 so that, similar to the heat pump mode, the entire amount of cold water flowing through the cold water discharge pipe 36 flows into the outdoor heat exchange inlet pipe 24, and the entire amount of hot water flowing through the hot water discharge pipe 35 flows into the outdoor heat exchange bypass pipe 26. As a result, the cold water cooled by the evaporator 13 directly flows into the outdoor heat exchanger 22.

[0036] The control unit controls the second four-way valve 28 so that part of the cold water flowing through the outdoor heat exchanger outlet pipe 27 is mixed with the warm water flowing through the outdoor heat exchanger bypass pipe 26. As a result, the flow rate of the warm water mixed in the fourth four-way valve 39 is offset, and the balance of the heat medium circulating in each of the hot water circuit 5 and the cold water circuit 7 is achieved.

[0037] The remaining cold water that has passed through the second four-way valve 28 is guided through the cold water pump 32, through the third four-way valve 37, and to the fourth four-way valve 39. In the fourth four-way valve 39, part of the warm water flowing through the indoor heat exchanger outlet pipe 42 is mixed with the cold water by the control unit. The cold water that has been mixed and become medium temperature is returned to the evaporator 13 through the cold water return pipe 45. By returning medium-temperature cold water to the evaporator 13 in this way, the temperature of the cold water flowing out of the evaporator 13 will rise compared to when in the heat pump mode.

[0038] <Heater mode> The heater mode is shown in FIG. 4. The heater mode is used when the outside air temperature is low, such as in winter, and sufficient heat absorption cannot be expected from the outdoor heat exchanger 22 even when heating operation is performed in the heat pump mode. In the heater mode, the cold water flowing out of the evaporator 13 is not guided to the outdoor heat exchanger 22 and the outdoor heat exchanger bypass pipe 26 is used.

[0039] Also, the heater mode in FIG. 4 is operated by the hot water pump 30, and the cold water pump 32 is stopped. Note that it may be operated by the cold water pump 32 and the hot water pump 30 may be stopped, or it may be operated by both the cold water pump 32 and the hot water pump 30.

[0040] In the hot water circuit 5, the hot water heated by the condenser 11 passes through the first four-way valve 20 and is guided to the second four-way valve 28 through the outdoor heat exchanger bypass pipe 26. As a result, no heat medium flows through the outdoor heat exchanger 22. In the first four-way valve 20, the cold water cooled by the evaporator 13 merges with the hot water.

[0041] The hot water that has exited the second four-way valve 28 is guided by the hot water pump 30 through the third four-way valve 37 to the indoor heat exchanger 18. In the indoor heat exchanger 18, the air in the vehicle interior is heated by exchanging heat with the hot water.

[0042] The hot water that has exited the indoor heat exchanger 18 is guided to the fourth four-way valve 39. A part 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.

[0043] In the cold water circuit 7, the cold water cooled by the evaporator 13 is guided to the first four-way valve 20 and merges with the hot water. The flow thereafter 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 into the cold water return pipe 45 is returned to the evaporator 13.

[0044] <Control Method> Next, a control method for transitioning from the above-described heat pump operation through the first transition mode and the second transition mode to the heater mode will be described with reference to FIG. 5.

[0045] While operating in the heat pump mode (step S1) shown in FIG. 1, if the control unit determines that the heat absorption amount in the outdoor heat exchanger 22 is equal to or less than a predetermined value due to a decrease in the outside air temperature or frosting of the outdoor heat exchanger, the transition to the heater mode shown in FIG. 4 is determined. Before transitioning to the heater mode, the first transition mode shown in FIG. 2 is performed (step S2).

[0046] In the first transition mode of step S2, as shown in FIG. 2, a part of the hot water is mixed with the cold water at the first four-way valve 20 to obtain medium-temperature cold water, thereby raising the temperature of the cold water flowing out of the evaporator 13. Thereby, the temperature of the cold water mixed with the hot water at the first four-way valve 20 during the heater mode can be raised in advance.

[0047] In step S3, the control unit determines whether or not the difference between the temperature of the suction air sucked into the outdoor heat exchanger 22 and the temperature of the cold water flowing into the outdoor heat exchanger 22 is equal to or greater than a first predetermined value. In the first transition mode, since the cold water absorbs heat from the outside air in the outdoor heat exchanger 22, the inlet temperature of the cold water flowing through the outdoor heat exchanger 22 is lower than the temperature of the suction air (inlet temperature) that exchanges heat with the cold water. Therefore, the difference between the suction air temperature and the inlet temperature of the cold water flowing through the outdoor heat exchanger 22 is a negative value. When this negative difference becomes equal to or greater than the first predetermined value, it is determined that the cold water temperature has risen, the end of the first transition mode is determined, and the process proceeds to the second transition mode (step S4). Note that instead of the inlet temperature of the cold water flowing through the outdoor heat exchanger 22, the evaporation temperature ET of the refrigerant in the evaporator 13 may be used.

[0048] Note that in step S3, control may be performed to increase the rotational speed of the compressor 10. Thereby, it is possible to suppress a decrease in the heating capacity in the indoor heat exchanger 18 due to a decrease in the amount of heat absorbed from the outside air in the first transition mode.

[0049] The inlet temperature of the cold water and the suction air temperature in the outdoor heat exchanger 22 are measured by a temperature sensor (not shown) and transmitted to the control unit.

[0050] The first predetermined value is set to a value such that the cold water does not dissipate heat to the outside air in the outdoor heat exchanger 22. The first predetermined value is determined in advance and stored in the control unit. However, the first predetermined value can be changed by the user. As the first predetermined value approaches 0, the inlet temperature of the cold water approaches the outside air temperature, and the temperature of the cold water flowing out of the evaporator 13 can be increased.

[0051] In step S4, the second transition mode is performed. In the second transition mode, as shown in FIG. 3, a part of the warm water is mixed with the cold water by the fourth four-way valve 39 to obtain medium-temperature cold water, thereby increasing the temperature of the cold water flowing out of the evaporator 13. Thereby, the temperature of the cold water mixed with the warm water by the first four-way valve 20 can be increased in advance during the heater mode.

[0052] In step S5, the control unit determines whether the difference between the suction air temperature sucked into the outdoor heat exchanger 22 and the evaporation temperature ET of the refrigerant in the evaporator 13 is equal to or greater than a second predetermined value. When this difference becomes equal to or greater than the second predetermined value, the second transition mode is terminated and the heater mode is entered (step S6). Note that instead of the evaporation temperature ET of the refrigerant in the evaporator 13, the inlet temperature of the chilled water flowing through the outdoor heat exchanger 22 may be used.

[0053] Note that in step S4, control may be performed to increase the rotational speed of the compressor 10. Thereby, it is possible to suppress a decrease in the heating capacity in the indoor heat exchanger 18 due to a decrease in the amount of heat absorbed from the outside air during the second transition mode.

[0054] The evaporation temperature ET of the refrigerant is, for example, the saturation vapor temperature calculated by the control unit by measuring the pressure with a refrigerant pressure sensor (not shown) provided in the evaporator 13.

[0055] When the second predetermined value, which is the difference between the suction air temperature and the evaporation temperature ET, is set to a negative value, the evaporation temperature ET is set closer to 0 than the outside air temperature, and the chilled water temperature flowing out of the evaporator 13 can be made closer to the outside air temperature.

[0056] In the heater mode of step S6, as shown in FIG. 4, the chilled water is merged with the warm water by the first four-way valve 20. At this time, since the temperature of the chilled water has been increased as much as possible by the first transition mode and the second transition mode in advance, a decrease in the temperature of the warm water after merging can be suppressed.

[0057] The effects of the present embodiment described above are as follows. In the heat pump mode, the heat medium flowing through the indoor heat exchanger 18 is hot water for heating, and the heat medium flowing through the outdoor heat exchanger 22 is cold water for heat absorption. Before switching from the heat pump mode to the heater mode, a first transition mode is provided in which the hot water flowing through the indoor heat exchanger 18 is mixed with the cold water flowing through the outdoor heat exchanger 22. Thereby, by raising the temperature of the cold water flowing through the outdoor heat exchanger 22, the temperature of the cold water flowing out from the evaporator 13 can be raised. Therefore, even when switching to the heater mode, even if the cold water flowing out from the evaporator 13 is mixed with the hot water flowing out from the condenser 11, the temperature drop of the heat medium can be minimized as much as possible, and the decrease in the heating capacity in the indoor heat exchanger 18 can be suppressed.

[0058] When the difference between the suction air temperature and the inlet temperature of the cold water flowing through the outdoor heat exchanger 22 becomes equal to or greater than a predetermined value, it is determined that the cold water temperature has risen and the first transition mode is terminated. Thereby, the cold water temperature can be raised to the same level as the outside air temperature.

[0059] A part of the cold water flowing from the outdoor heat exchanger 22 to the evaporator 13 is mixed with the hot water flowing from the indoor heat exchanger 18 to the condenser 11. Thereby, it is possible to avoid causing a temperature drop of the hot water by mixing cold water upstream of the indoor heat exchanger 18, and it is possible to maintain the temperature of the hot water flowing into the indoor heat exchanger 18 and ensure the heating capacity.

[0060] A second transition mode is provided in which a part of the hot water flowing from the indoor heat exchanger 18 to the condenser 11 is mixed with the cold water flowing from the outdoor heat exchanger 22 to the evaporator 13. Thereby, the temperature of the cold water flowing into the evaporator 13 can be raised to raise the evaporation temperature ET of the refrigerant, and the temperature of the cold water flowing out from the evaporator 13 can be raised.

[0061] In the second transition mode, the cold water flowing out from the evaporator 13 is not mixed with the hot water but is sent to the outdoor heat exchanger 22. Therefore, while ensuring heat absorption from the air in the outdoor heat exchanger 22, the cold water temperature can be made higher than that in the first transition mode.

[0062] When the first transition mode or the second transition mode is performed, the heat absorption amount from the outside air gradually decreases, and the heating amount in the indoor heat exchanger 18 decreases. In order to compensate for this decrease in the heating amount, the rotational speed of the compressor was increased.

[0063] In the above-described embodiment, both the first transition mode and the second transition mode are used, but either one of these modes may be used. For example, after step S3 shown in FIG. 5, the second transition mode of step S4 may be omitted and the process may proceed to the heater mode of step S6.

[0064] Alternatively, as shown in FIG. 6, after executing the first transition mode or the second transition mode in step S21, an end determination may be made based on the relationship between the evaporation temperature ET of the refrigerant and the suction air temperature as in step S5, and the process may proceed to the heater mode of step S6. Note that, instead of the evaporation temperature ET of the refrigerant in the evaporator 13, the inlet temperature of the chilled water flowing through the outdoor heat exchanger 22 may be used.

[0065] [Second Embodiment] Next, a second embodiment of the present disclosure will be described with reference to FIG. 7 and the like. The vehicle air conditioner 1 in FIG. 7 has a different configuration of the heat medium circuit compared to the first embodiment. In the following description, the configurations different from those of the first embodiment will be described, and the same components will be denoted by the same reference numerals and their descriptions will be omitted.

[0066] The hot water circuit 5 is a flow path that mainly supplies the hot water heated by the condenser 11 to the indoor heat exchanger (temperature control device) 18 and returns the hot water flowing out from the indoor heat exchanger 18 to the condenser 11.

[0067] The hot water circuit 5 includes a hot water pump 30 connected to the hot water outlet pipe 19. The chilled water circuit 7 includes a chilled water pump 32 connected to the chilled water outlet pipe 21. The rotational speeds, that is, the flow rates, of the hot water pump 30 and the chilled water pump 32 are controlled by the control unit.

[0068] 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 are an indoor heat exchanger 18, an outdoor heat exchanger 22, and a battery heat exchanger 50.

[0069] An indoor heat exchange upstream three-way valve 52a is provided in the indoor heat exchange inlet pipe 41 on the upstream side of the indoor heat exchanger 18, and an indoor heat exchange downstream three-way valve 52b is provided in the indoor heat exchange outlet pipe 42 on the downstream side of the indoor heat exchanger 18. The opening degree of the indoor heat exchange upstream three-way valve 52a is controlled by the control unit, and hot water from the hot water pump 30 and cold water from the cold water pump 32 can flow into the indoor heat exchanger 18. The indoor heat exchange downstream three-way valve 52b is controlled by the control unit, and the hot water or cold water flowing out of the indoor heat exchanger 18 can flow into the hot water return pipe 44 and the cold water return pipe 45. The indoor heat exchange upstream three-way valve 52a and the indoor heat exchange downstream three-way valve 52b are controlled to have the same opening degree synchronously by one actuator. Note that the present disclosure is not limited to the three-way valves described above, and other three-way valves or two-way valves may be combined.

[0070] An outdoor heat exchange upstream three-way valve 53a is provided in the outdoor heat exchange inlet pipe 24 on the upstream side of the outdoor heat exchanger 22, and an outdoor heat exchange downstream three-way valve 53b is provided in the outdoor heat exchange outlet pipe 27 on the downstream side of the outdoor heat exchanger 22. The opening degree of the outdoor heat exchange upstream three-way valve 53a is controlled by the control unit, and hot water from the hot water pump 30 and cold water from the cold water pump 32 can flow into the outdoor heat exchanger 22. The outdoor heat exchange downstream three-way valve 53b is controlled by the control unit, and the hot water or cold water flowing out of the outdoor heat exchanger 22 can flow into the hot water return pipe 44 and the cold water return pipe 45. The outdoor heat exchange upstream three-way valve 53a and the outdoor heat exchange downstream three-way valve 53b are controlled to have the same opening degree synchronously by one actuator. Note that the present disclosure is not limited to the three-way valves described above, and other three-way valves or two-way valves may be combined.

[0071] On the battery heat exchange inlet pipe 54 on the upstream side of the battery heat exchanger 50, a battery heat exchange upstream three-way valve 56a is provided. On the battery heat exchange outlet pipe 55 on the downstream side of the battery heat exchanger 50, a battery heat exchange downstream three-way valve 56b is provided. The opening degree of the battery heat exchange upstream three-way valve 56a is controlled by a control unit (not shown), and hot water from the hot water pump 30 and cold water from the cold water pump 32 can flow into the battery heat exchanger 50. The battery heat exchange downstream three-way valve 56b is controlled by a control unit (not shown), and the hot water or cold water flowing out of the battery heat exchanger 50 can flow into the hot water return pipe 44 and the cold water return pipe 45. The battery heat exchange upstream three-way valve 56a and the battery heat exchange downstream three-way valve 56b are controlled to have synchronized opening degrees by one actuator. Note that the present disclosure is not limited to the three-way valves described above, and other three-way valves or two-way valves may be combined.

[0072] On the battery heat exchange inlet pipe 54, a battery water pump 58 whose operation is controlled by a control unit is provided. On the upstream side of the battery water pump 58, a connecting pipe 59 that connects the battery heat exchange inlet pipe 54 and the battery heat exchange outlet pipe 55 is provided.

[0073] A heat medium bypass pipe 47 is provided between the hot water outlet pipe 19 on the upstream side of the hot water pump 30 and the cold water outlet pipe 21 on the upstream side of the cold water pump 32. Through the heat medium bypass pipe 47, hot water flows from the hot water circuit 5 to the cold water circuit 7, or cold water flows from the cold water circuit 7 to the hot water circuit 5. A reserve tank 48 for storing hot water or cold water is provided in the heat medium bypass pipe 47.

[0074] Next, each operation mode using the vehicle air conditioner 1 having the above configuration will be described. <Heat pump mode> The heat pump mode will be described with reference to FIG. 7. In the refrigerant circuit 3, the refrigerant compressed by the compressor 10 is sent to the condenser 11 and condensed. When the refrigerant is condensed, the latent heat of condensation is given to the hot water, which is the heat medium flowing through the condenser 11, to heat it.

[0075] The liquid refrigerant that exits the condenser 11 is depressurized by the expansion valve 12 and guided to the evaporator 13. In the evaporator 13, as the refrigerant evaporates, the latent heat of evaporation is taken from the chilled water, which is the heat medium flowing through the evaporator 13, and the chilled water is cooled.

[0076] The warm water heated in the condenser 11 is guided by the hot water pump 30 through the indoor heat exchange upstream three-way valve 52a to the indoor heat exchanger 18. In the indoor heat exchanger 18, the air in the vehicle interior is heated by exchanging heat with the air.

[0077] The warm water that exits the indoor heat exchanger 18 passes through the indoor heat exchange downstream three-way valve 52b and is returned to the condenser 11 via the warm water return pipe 44.

[0078] The chilled water cooled in the evaporator 13 is guided by the chilled water pump 32 through the outdoor heat exchange upstream three-way valve 53a to the outdoor heat exchanger 22. In the outdoor heat exchanger 22, the chilled water is heated by absorbing heat from the outside air.

[0079] The chilled water that exits the outdoor heat exchanger 22 passes through the outdoor heat exchange downstream three-way valve 53b and is returned to the evaporator 13 through the chilled water return pipe 45.

[0080] <First Transition Mode> Figure 8 shows the first transition mode. The following only explains the operations that change with respect to the heat pump mode described above.

[0081] The control unit controls the indoor heat exchange upstream three-way valve 52a to distribute the warm water guided from the warm water discharge pipe 35 to the indoor heat exchange inlet pipe 41 and the chilled water discharge pipe 36. The warm water distributed to the chilled water discharge pipe 36 merges with the chilled water on the upstream side of the outdoor heat exchange upstream three-way valve 53a to become medium-temperature chilled water and flows through the outdoor heat exchange upstream three-way valve 53a to the outdoor heat exchange inlet pipe 24. In each of the following figures, a three-way valve controlled to mix or distribute fluids is shown surrounded by a dashed circle.

[0082] The medium-temperature cold water is guided to the outdoor heat exchanger 22, absorbs heat from the air (outdoor air) in the outdoor heat exchanger 22, and then is guided to the downstream three-way valve 53b of the outdoor heat exchanger through the outdoor heat exchange outlet pipe 27. At the downstream three-way valve 53b of the outdoor heat exchanger, the cold water that has been made medium-temperature is distributed to the hot water return pipe 44 and the cold water return pipe 45. As a result, the flow rate of the hot water supplied from the hot water circuit 5 to the cold water circuit 7 at the upstream three-way valve 52a of the indoor heat exchanger is recovered to the hot water circuit 5 at the downstream three-way valve 53b of the outdoor heat exchanger, and the balance of the heat medium circulating in each of the hot water circuit 5 and the cold water circuit 7 is achieved.

[0083] The medium-temperature cold water guided to the cold water return pipe 45 is returned to the evaporator 13. By returning the medium-temperature cold water to the evaporator 13 in this way, the temperature of the cold water flowing out of the evaporator 13 will rise compared to when in the heat pump mode.

[0084] The above-described first transition mode can be modified as shown in FIG. 9. As shown in FIG. 9, at the upstream three-way valve 52a of the indoor heat exchanger, hot water is made to flow only into the indoor heat exchange inlet pipe 41, and the upstream three-way valve 53a of the outdoor heat exchanger is controlled so that a part of the hot water guided from the hot water discharge pipe 35 is mixed with the cold water guided from the cold water discharge pipe 36. As a result, medium-temperature cold water may be made to flow through the outdoor heat exchange inlet pipe 24. Other operations are the same as those in the first transition mode of FIG. 8.

[0085] <Second Transition Mode> FIG. 10 shows the second transition mode. The following will only explain the operations that are changed with respect to the above-described first transition mode.

[0086] The control unit controls the downstream three-way valve 53b of the outdoor heat exchanger and mixes a part of the hot water flowing through the hot water return pipe 44 with the cold water guided from the outdoor heat exchange outlet pipe 27. The cold water that has become medium-temperature by mixing a part of the hot water is returned to the evaporator 13 through the cold water return pipe 45. By returning the medium-temperature cold water to the evaporator 13 in this way, the temperature of the cold water flowing out of the evaporator 13 will rise compared to when in the heat pump mode.

[0087] The control unit controls the three-way valve 53a upstream of the outdoor heat exchanger, and mixes a part of the cold water led from the cold water discharge pipe 36 with the hot water flowing through the hot water discharge pipe 35. Thereby, the flow rate of the hot water mixed in the three-way valve 53b downstream of the outdoor heat exchanger is offset, and the balance of the heat medium circulating in each of the hot water circuit 5 and the cold water circuit 7 is achieved.

[0088] The second transition mode described above can be modified as shown in FIG. 11. As shown in FIG. 11, in the three-way valve 53a upstream of the outdoor heat exchanger, the cold water led from the cold water discharge pipe 36 may be made to flow only into the outdoor heat exchanger inlet pipe 24, and in the three-way valve 52a upstream of the indoor heat exchanger, a part of the cold water led from the cold water discharge pipe 36 may be mixed with the hot water. Other operations are the same as in the second transition mode of FIG. 10.

[0089] <Heater mode> The heater mode is shown in FIG. 12. Different from the heat pump mode, in the heater mode, similar to the first embodiment, the cold water flowing out of the evaporator 13 is not led to the outdoor heat exchanger 22, but is mixed with the hot water and then led to the indoor heat exchanger 18. The hot water flowing out of the indoor heat exchanger 18 is distributed to the condenser 11 and the evaporator 13.

[0090] According to the command of the control unit, the cold water pump 32 is stopped, and only the hot water pump 30 is operated. The cold water flowing out of the evaporator 13 is mixed with the hot water flowing through the hot water outlet pipe 19 through the heat medium bypass pipe 47. The mixed hot water is led to the indoor heat exchanger 18 through the three-way valve 52a upstream of the indoor heat exchanger. In the indoor heat exchanger 18, the air is heated by exchanging heat with the air in the vehicle interior.

[0091] The hot water that has exited the indoor heat exchanger 18 is distributed to the hot water return pipe 44 and the cold water return pipe 45 through the three-way valve 52b downstream of the indoor heat exchanger. A part of the hot water is returned to the condenser 11, and the remaining hot water is returned to the evaporator 13.

[0092] For the outdoor heat exchanger 22, the three-way valve 53a upstream of the outdoor heat exchanger and the three-way valve 53b downstream of the outdoor heat exchanger are fully closed, and no heat medium (hot water or cold water) flows through.

[0093] Incidentally, in the heater mode, as shown in FIG. 13, not only the hot water pump 30 but also the cold water pump 32 may be activated. In this case, the cold water is mixed with the hot water by the three-way valve 52a upstream of the indoor heat exchanger. Incidentally, only the cold water pump 32 may be activated. In this case, the hot water passes through the heat medium bypass pipe 47 and is mixed with the cold water flowing through the cold water outlet pipe 21.

[0094] <Control method> The control method for reaching the heater mode from the heat pump operation through the first transition mode and the second transition mode is the same as that of the first embodiment described with reference to FIGS. 5 and 6, and thus the description thereof is omitted.

[0095] The effects of the present embodiment described above are as follows. In the heat pump mode, the heat medium flowing through the indoor heat exchanger 18 is hot water for heating, and the heat medium flowing through the outdoor heat exchanger 22 is cold water for heat absorption. Before switching from the heat pump mode to the heater mode, a first transition mode is provided in which the hot water flowing through the indoor heat exchanger 18 is mixed with the cold water flowing through the outdoor heat exchanger 22. Thereby, the temperature of the cold water flowing through the outdoor heat exchanger 22 can be increased, and thus the temperature of the cold water flowing out from the evaporator 13 can be increased. Therefore, even when switching to the heater mode, even if the cold water flowing out from the evaporator 13 is mixed with the hot water flowing out from the condenser 11, the temperature drop of the heat medium can be minimized as much as possible, and the decrease in the heating capacity in the indoor heat exchanger 18 can be suppressed.

[0096] When the difference between the suction air temperature and the inlet temperature of the cold water flowing through the outdoor heat exchanger 22 becomes equal to or greater than a predetermined value, it is determined that the cold water temperature has risen, and the first transition mode is terminated. Thereby, the cold water temperature can be increased to be equivalent to the outside air temperature.

[0097] A part of the chilled water flowing from the outdoor heat exchanger 22 to the evaporator 13 is mixed with the warm water flowing from the indoor heat exchanger 18 to the condenser 11. As a result, it is possible to avoid mixing chilled water upstream of the indoor heat exchanger 18 and causing a temperature drop in the warm water, and to maintain the temperature of the warm water flowing into the indoor heat exchanger 18 and ensure the heating capacity.

[0098] A second transition mode is provided in which a part of the warm water flowing from the indoor heat exchanger 18 to the condenser 11 is mixed with the chilled water flowing from the outdoor heat exchanger 22 to the evaporator 13. As a result, the temperature of the chilled water flowing into the evaporator 13 can be increased, the evaporation temperature ET of the refrigerant can be increased, and the temperature of the chilled water flowing out of the evaporator 13 can be increased.

[0099] In the second transition mode, the chilled water flowing out of the evaporator 13 is not mixed with the warm water but is sent to the outdoor heat exchanger 22. Therefore, while ensuring heat absorption from the air in the outdoor heat exchanger 22, the chilled water temperature can be made higher than in the first transition mode.

[0100] When the first transition mode or the second transition mode is performed, the amount of heat absorbed from the outside air gradually decreases, and the heating amount in the indoor heat exchanger 18 decreases. In order to compensate for this decrease in the heating amount, the rotation speed of the compressor is increased.

[0101] In the above-described embodiment, both the first transition mode and the second transition mode are used, but either one of these modes may be used. For example, after step S3 shown in FIG. 5, the second transition mode of step S4 may be omitted and the process may proceed to the heater mode of step S6.

[0102] Alternatively, as shown in FIG. 6, after executing the first transition mode or the second transition mode in step S21, an end determination may be made based on the relationship between the evaporation temperature ET of the refrigerant and the suction air temperature as in step S5, and the process may proceed to the heater mode of step S6. Note that instead of the evaporation temperature ET of the refrigerant in the evaporator 13, the inlet temperature of the chilled water flowing through the outdoor heat exchanger 22 may be used.

[0103] The temperature control system and its control method described in each of the above embodiments can be understood as follows, for example.

[0104] The temperature control system (1) according to the first aspect of the present disclosure includes 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, a refrigerant circuit (3), a heat medium circuit (5, 7) 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. The heat medium circuit includes a temperature control device (18) that exchanges heat between the heat medium and the temperature control target, and an outdoor heat exchanger (22) that exchanges heat between the heat medium and the outside air. The control unit has 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, a heater mode in which at least a part of the heat medium flowing out of the high-pressure side heat exchanger and at least a part of the heat medium flowing out of the low-pressure side heat exchanger are mixed, at least a part of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger, and a first transition mode in which, before switching from the heat pump mode to the heater mode, the heat medium flowing through the temperature control device is mixed with the heat medium flowing through the outdoor heat exchanger.

[0105] In the heat pump mode, the heat medium flowing through the temperature control device is a relatively high-temperature heat medium (hot) for heating, and the heat medium flowing through the outdoor heat exchanger is a relatively low-temperature heat medium (cold) for heat absorption. Before switching from the heat pump mode to the heater mode, a first transition mode is provided in which the heat medium (hot) flowing through the temperature control device is mixed with the heat medium (cold) flowing through the outdoor heat exchanger. As a result, by raising the temperature of the heat medium (cold) flowing through the outdoor heat exchanger, the temperature of the heat medium (cold) flowing out of the low-pressure side heat exchanger can be raised. Therefore, even when switching to the heater mode, even if the heat medium (cold) flowing out of the low-pressure side heat exchanger is mixed with the heat medium (hot) flowing out of the high-pressure side heat exchanger, the temperature drop of the heat medium can be minimized as much as possible, and a decrease in the heating capacity in the temperature control device can be suppressed.

[0106] In the temperature control system according to the second aspect of the present disclosure, in the first aspect, in the first transition mode, when the difference between the inlet temperature of the fluid that exchanges heat with the heat medium flowing through the outdoor heat exchanger and the inlet temperature of the heat medium flowing through the outdoor heat exchanger is equal to or greater than a predetermined value, or when the difference between the inlet temperature of the fluid that exchanges heat with the heat medium flowing through the outdoor heat exchanger and the evaporation temperature of the refrigerant flowing through the low-pressure side heat exchanger is equal to or greater than a predetermined value, the first transition mode is terminated.

[0107] In the first transition mode, since the heat medium absorbs heat in the outdoor heat exchanger, the inlet temperature of the heat medium (cold) flowing through the outdoor heat exchanger is lower than the inlet temperature of the fluid (for example, outside air) that exchanges heat with the heat medium (cold). Therefore, the difference between the inlet temperature of the fluid that exchanges heat with the heat medium (cold) flowing through the outdoor heat exchanger and the inlet temperature of the heat medium (cold) flowing through the outdoor heat exchanger is a negative value. When this negative difference becomes equal to or greater than a predetermined value, it can be determined that the cold water temperature has risen, and the first transition mode can be terminated. Also, the difference between the inlet temperature of the fluid that exchanges heat with the heat medium (cold) in the outdoor heat exchanger and the evaporation temperature of the refrigerant is a negative value. When this negative difference becomes equal to or greater than a predetermined value, it can be determined that the amount of heat absorbed by the refrigerant from the fluid has decreased, and the first transition mode can be terminated. When the first transition mode ends, for example, it shifts to the heater mode or the second transition mode described later.

[0108] In the temperature control system according to the third aspect of the present disclosure, in the first aspect or the second aspect, in the first transition mode, a part of the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger is mixed with the heat medium flowing from the temperature control device to the high-pressure side heat exchanger.

[0109] A part of the heat medium (cold) flowing from the outdoor heat exchanger to the low-pressure side heat exchanger is mixed with the heat medium (warm) flowing from the temperature control device to the high-pressure side heat exchanger. Thereby, it is possible to avoid mixing the heat medium (cold) upstream of the temperature control device and causing a temperature drop of the heat medium (warm), and to maintain the temperature of the heat medium (warm) flowing to the temperature control device and ensure the heating capacity.

[0110] In the temperature control system according to the fourth aspect of the present disclosure, in the first aspect or the second aspect, the control unit has a second transition mode in which a part of the heat medium flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger.

[0111] A second transition mode is provided in which a part of the heat medium (warm) flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium (cold) flowing from the outdoor heat exchanger to the low-pressure side heat exchanger. Thereby, it is possible to raise the temperature of the heat medium (cold) flowing to the low-pressure side heat exchanger, raise the evaporation temperature of the refrigerant, and raise the temperature of the heat medium (cold) flowing out of the low-pressure side heat exchanger. In the second transition mode, the cold water flowing out from the evaporator 13 is flowed to the outdoor heat exchanger 22 without being mixed with the warm water. Therefore, while ensuring heat absorption from the air in the outdoor heat exchanger 22, the cold water temperature can be made higher than that in the first transition mode. The second transition mode can be performed after the first transition mode.

[0112] In the temperature control system according to the fifth aspect of the present disclosure, in any one of the first aspect to the fourth aspect, when the first transition mode occurs, the rotation speed of the compressor is increased.

[0113] When the first transition mode or the second transition mode is performed, the amount of heat absorbed from the outside air gradually decreases, and the amount of heat generation in the temperature control device decreases. In order to compensate for this decrease in the amount of heat generation, the rotational speed of the compressor was increased.

[0114] In the temperature control system according to the sixth aspect of the present disclosure, in any one of the first aspect to the fifth aspect, when the second transition mode is performed, the rotational speed of the compressor is increased.

[0115] When the first transition mode or the second transition mode is performed, the amount of heat absorbed from the outside air gradually decreases, and the amount of heat generation in the temperature control device decreases. In order to compensate for this decrease in the amount of heat generation, the rotational speed of the compressor was increased.

[0116] The temperature control system according to the seventh aspect of the present disclosure includes 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 refrigerant circuit having a heat medium circuit in which a heat medium that exchanges heat with the refrigerant circulates in the high-pressure side heat exchanger and the low-pressure side heat exchanger, and 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 the temperature control target, and an outdoor heat exchanger that exchanges heat between the heat medium and the outside air. The control unit guides the heat medium flowing out of the high-pressure side heat exchanger to the temperature control device, and at the same time, guides the heat medium flowing out of the low-pressure side heat exchanger to the outdoor heat exchanger. A heat pump mode, at least a part of the heat medium flowing out of the high-pressure side heat exchanger and at least a part of the heat medium flowing out of the low-pressure side heat exchanger are mixed, and at least a part of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger. A heater mode, and a second transition mode in which a part of the heat medium flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger.

[0117] In the heat pump mode, the heat medium flowing through the temperature control device is a relatively high-temperature heat medium (hot) for heating, and the heat medium flowing through the outdoor heat exchanger is a relatively low-temperature heat medium (cold) for heat absorption. Before switching from the heat pump mode to the heater mode, a second transition mode is provided in which a part of the heat medium (hot) flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium (cold) flowing from the outdoor heat exchanger to the low-pressure side heat exchanger. As a result, the temperature of the heat medium (cold) flowing into the low-pressure side heat exchanger can be increased, the evaporation temperature of the refrigerant can be increased, and the temperature of the heat medium (cold) flowing out of the low-pressure side heat exchanger can be increased. In the second transition mode, the cold water flowing out of the evaporator 13 is directly sent to the outdoor heat exchanger 22 without being mixed with the hot water. Therefore, while ensuring heat absorption from the air in the outdoor heat exchanger 22, the cold water temperature can be made higher than that in the first transition mode. When the second transition mode ends, for example, the system shifts to the heater mode.

[0118] The control method of the temperature control system according to the first aspect of the present disclosure is a control method of a temperature control 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 by 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 includes a temperature control device that exchanges heat between the heat medium and the temperature control target, and an outdoor heat exchanger that exchanges heat between the heat medium and the outside air. The control method includes 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, a heater mode in which at least a part of the heat medium flowing out of the high-pressure side heat exchanger and at least a part of the heat medium flowing out of the low-pressure side heat exchanger are mixed, at least a part of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger, and a first transition mode in which, before switching from the heat pump mode to the heater mode, the heat medium flowing through the temperature control device is mixed with the heat medium flowing through the outdoor heat exchanger.

[0119] The control method of the temperature control system according to the second 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 by 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 includes a temperature control device that exchanges heat between the heat medium and the temperature control target, and an outdoor heat exchanger that exchanges heat between the heat medium and the outside air. The control method of the temperature control system is as follows: 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; a heater mode in which at least a part of the heat medium flowing out from the high-pressure side heat exchanger and at least a part of the heat medium flowing out from the low-pressure side heat exchanger are mixed, at least a part of the heat medium flowing out from the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger; and a second transition mode in which a part of the heat medium flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger.

Explanation of symbols

[0120] 1 Vehicle air conditioner (temperature control system) 3 Refrigerant circuit 5 Hot water circuit (heat medium circuit) 7 Cold 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 device) 19 Hot water outlet pipe 20 First four-way valve 21 Cold water outlet pipe 22 Outdoor heat exchanger 24 Outdoor heat exchange inlet pipe 26 Outdoor heat exchange bypass pipe 27 Outdoor heat exchanger outlet pipe 28 Second four-way valve 30 Hot water pump 31 Hot water pump inlet pipe 32 Cold water pump 33 Cold water pump inlet pipe 35 Hot water discharge pipe 36 Cold water discharge pipe 37 Third four-way valve 39 Fourth four-way valve 40 Four-way valve connection pipe 41 Indoor heat exchanger inlet pipe 42 Indoor heat exchanger outlet pipe 44 Hot water return pipe 45 Cold water return pipe 47 Heat medium bypass pipe 48 Reserve tank 50 Heat exchanger for battery (secondary battery) 52a Upstream three-way valve of indoor heat exchanger 52b Downstream three-way valve of indoor heat exchanger 53a Upstream three-way valve of outdoor heat exchanger 53b Downstream three-way valve of outdoor heat exchanger 54 Heat exchanger inlet pipe for battery 55 Heat exchanger outlet pipe for battery 56a Upstream three-way valve of heat exchanger for battery 56b Downstream three-way valve of heat exchanger for battery 58 Water pump for battery 59 Connecting pipe

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 in which a heat medium circulates to exchange 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 heat pump 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 guides the heat medium flowing out of the low-pressure side heat exchanger to the outdoor heat exchanger; a heater mode in which at least a portion of the heat medium flowing out of the high-pressure side heat exchanger and at least a portion of the heat medium flowing out of the low-pressure side heat exchanger are mixed, at least a portion of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger; a first transition mode in which the heat medium circulating through the temperature control device is mixed with the heat medium circulating through the outdoor heat exchanger before switching from the heat pump mode to the heater mode; A temperature control system having the above structure.

2. In the first transition mode, the control unit When a difference between the temperature of the heat medium flowing through the outdoor heat exchanger and the inlet temperature of a fluid exchanging heat with the heat medium becomes equal to or greater than a predetermined value, or When the difference between the evaporation temperature of the refrigerant flowing in the low-pressure side heat exchanger and the temperature of the fluid exchanging heat with the heat medium flowing in the outdoor heat exchanger becomes equal to or greater than a predetermined value, The temperature control system according to claim 1 , wherein the first transition mode is terminated.

3. The temperature control system according to claim 1 or 2, wherein the first transition mode mixes a portion of the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger with the heat medium flowing from the temperature control device to the high-pressure side heat exchanger.

4. The temperature control system according to claim 1 or 2, wherein the control unit has a second transition mode in which a portion of the heat medium flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger.

5. The temperature adjustment system according to claim 1 , wherein the rotation speed of the compressor is increased in the first transition mode.

6. The temperature adjustment system according to claim 4 , wherein the rotation speed of the compressor is increased in the second transition mode.

7. 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 in which a heat medium circulates to exchange 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 heat pump 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 guides the heat medium flowing out of the low-pressure side heat exchanger to the outdoor heat exchanger; a heater mode in which at least a portion of the heat medium flowing out of the high-pressure side heat exchanger and at least a portion of the heat medium flowing out of the low-pressure side heat exchanger are mixed, at least a portion of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger; a second transition mode in which a part of the heat medium flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger; A temperature control system having the above structure.

8. The temperature adjustment system according to claim 7 , wherein the rotation speed of the compressor is increased in the second transition mode.

9. 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 to exchange heat with a refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger, The heat medium circuit includes 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 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; a heater mode in which at least a portion of the heat medium flowing out of the high-pressure side heat exchanger and at least a portion of the heat medium flowing out of the low-pressure side heat exchanger are mixed, at least a portion of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger; a first transition mode in which the heat medium circulating through the temperature control device is mixed with the heat medium circulating through the outdoor heat exchanger before switching from the heat pump mode to the heater mode; A method for controlling a temperature adjustment system having the above structure.

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 to exchange heat with a refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger, The heat medium circuit includes 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 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; a heater mode in which at least a portion of the heat medium flowing out of the high-pressure side heat exchanger and at least a portion of the heat medium flowing out of the low-pressure side heat exchanger are mixed, at least a portion of the heat medium flowing out of the high-pressure side heat exchanger is guided to the temperature control device, and the mixed heat medium is guided to the high-pressure side heat exchanger and the low-pressure side heat exchanger; a second transition mode in which a part of the heat medium flowing from the temperature control device to the high-pressure side heat exchanger is mixed with the heat medium flowing from the outdoor heat exchanger to the low-pressure side heat exchanger; A method for controlling a temperature adjustment system having the above structure.

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