Temperature control system and method for controlling a temperature control system

Abstract

To extend the lifespan of a temperature control system that executes a heater mode for supplying a heat medium heated by the power of a compressor to temperature control equipment at low outside air temperatures. 【Solution means】The heat medium circuit 20 includes an indoor air conditioning unit 25, a first pump 21 that pumps the heat medium HM that has passed through the condenser 12, and a second pump 22 that pumps the heat medium HM that has passed through the evaporator 14. The control unit 30 operates only the first pump 21 to combine the heat medium HM that has passed through the condenser 12 and the heat medium HM that has passed through the evaporator 14 through the communication flow path L5 and supply it to the indoor air conditioning unit 25 in a first heater mode, and operates only the second pump 22 to combine the heat medium HM that has passed through the condenser 12 and the heat medium HM that has passed through the evaporator 14 through the communication flow path L5 and supply it to the indoor air conditioning unit 25 in a second heater mode, and provides a temperature control system 100 that switches and executes these modes.

Description

Technical Field

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

Background Art

[0002] Conventionally, a vehicle thermal management system having an operation mode for heating a device to be heated at an early stage at a low outside air temperature is known (see, for example, Patent Document 1). The vehicle thermal management system disclosed in Patent Document 1 arranges a low-pressure side heat exchanger included in a refrigeration cycle in which a refrigerant circulates in a first cooling water circuit and circulates cooling water by a first pump, and arranges a high-pressure side heat exchanger included in the refrigeration cycle in a second cooling water circuit and circulates cooling water by a second pump, thereby performing a heat pump operation.

[0003] When the vehicle thermal management system disclosed in Patent Document 1 executes an operation mode for heating a device to be heated at an early stage at a low outside air temperature, both the first pump and the second pump are operated, and cooling water circulating in the first cooling water circuit and cooling water circulating in the second cooling water circuit are both supplied to a heater core, which is a device to be heated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, when executing an operation mode for heating a device to be heated at an early stage at a low outside air temperature, it is always necessary to operate both the first pump and the second pump. Therefore, by executing this operation mode, a load is simultaneously applied to both the first pump and the second pump, and there is a possibility that either the first pump or the second pump fails and the life of the system is shortened.

[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 method for controlling a temperature control system capable of extending the life of a temperature control system that executes a heater mode in which a heat medium heated by the power of a compressor is supplied to a temperature control device at a low outside air temperature.

Means for Solving the Problems

[0007] A temperature control system according to an aspect of the present disclosure includes a refrigerant circuit in which a refrigerant circulates through a compressor, a high-pressure side heat exchanger, a decompression unit, and a low-pressure side heat exchanger; 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 heats a temperature control target using the heat medium, a flow path branching unit that is disposed downstream of the temperature control device in the flow direction of the heat medium and guides the heat medium to at least one of a first heat medium flow path that guides the heat medium to the high-pressure side heat exchanger and a second heat medium flow path that guides the heat medium to the low-pressure side heat exchanger, a flow path merging unit that is disposed upstream of the temperature control device in the flow direction and merges the heat medium flowing through the first heat medium flow path and the heat medium flowing through the second heat medium flow path and guides the merged heat medium to the temperature control device, a first pump that is disposed in the first heat medium flow path and pumps the heat medium that has passed through the high-pressure side heat exchanger along the flow direction, a second pump that is disposed in the second heat medium flow path and pumps the heat medium that has passed through the low-pressure side heat exchanger along the flow direction, and a communication flow path that communicates a downstream side of the first heat medium flow path downstream of the high-pressure side heat exchanger in the flow direction and a downstream side of the second heat medium flow path downstream of the low-pressure side heat exchanger in the flow direction. The control unit switches between and executes a first heater mode in which only the first pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communication flow path and supply the merged heat medium to the temperature control device, and a second heater mode in which only the second pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communication flow path and supply the merged heat medium to the temperature control device.

[0008] In a method for controlling a temperature control system according to an aspect of the present disclosure, the temperature control system includes a refrigerant circuit in which a refrigerant circulates through a compressor, a high-pressure side heat exchanger, a decompression unit, and a low-pressure side heat exchanger, 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 heats a temperature control target using the heat medium, a flow path branching unit that is disposed downstream of the temperature control device in the flow direction of the heat medium and guides the heat medium to at least one of a first heat medium flow path that guides the heat medium to the high-pressure side heat exchanger and a second heat medium flow path that guides the heat medium to the low-pressure side heat exchanger, a flow path merging unit that is disposed upstream of the temperature control device in the flow direction and merges the heat medium flowing through the first heat medium flow path and the heat medium flowing through the second heat medium flow path, a first pump that is disposed in the first heat medium flow path and pumps the heat medium that has passed through the high-pressure side heat exchanger along the flow direction, a second pump that is disposed in the second heat medium flow path and pumps the heat medium that has passed through the low-pressure side heat exchanger along the flow direction, and a communication flow path that communicates a downstream side of the first heat medium flow path downstream of the high-pressure side heat exchanger in the flow direction and a downstream side of the second heat medium flow path downstream of the low-pressure side heat exchanger in the flow direction. A control step is provided for controlling the refrigerant circuit and the heat medium circuit so as to switch between and execute a first heater mode in which only the first pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger through the communication flow path and supply the merged heat medium to the temperature control device, and a second heater mode in which only the second pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger through the communication flow path and supply the merged heat medium to the temperature control device.

Effect of the Invention

[0009] According to the present disclosure, it is possible to provide a temperature control system and a method for controlling a temperature control system that can extend the life of a temperature control system that executes a heater mode of supplying a heat medium heated by the power of a compressor to a temperature control device at low outside air temperatures.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0011] Hereinafter, a temperature control system 100 according to an embodiment of the present disclosure will be described with reference to the drawings. The vehicle temperature control system 100 shown in FIG. 1 is equipped in a vehicle (not shown) such as, for example, an electric vehicle that does not have an engine and obtains driving force for vehicle running from a driving electric motor for running, or a so-called hybrid vehicle that obtains driving force for vehicle running from an engine and an electric motor.

[0012] The temperature control system 100 is responsible for air conditioning such as heating, cooling, dehumidifying, and ventilating the passenger compartment where the passengers are on board, as well as heat management of in-vehicle devices such as a battery device (power supply device), a driving motor, and electronic devices that generate heat mounted on the vehicle, and waste heat recovery. The general term "heat management" shall refer to air conditioning to an appropriate temperature and humidity and managing in-vehicle devices at an appropriate temperature.

[0013] In the temperature control system 100 and the electric and electronic devices provided in the in-vehicle device, electric power stored in the in-vehicle battery device is supplied. The in-vehicle battery device is charged from an external power source when the vehicle is stopped.

[0014] The temperature control system 100 includes a refrigerant circuit 10 configured to allow the refrigerant RF to circulate, a heat medium circuit 20 configured to allow a heat medium that exchanges heat with the refrigerant RF to circulate, and a control unit 30 that controls the refrigerant circuit 10 and the heat medium circuit 20. The control unit 30 sets the temperature control system 100 to a predetermined operation mode and controls the operation state of the temperature control system 100 according to the operation mode. The temperature control system 100 includes sensors (not shown) such as a sensor that detects the outside air temperature and a sensor that detects the temperature of the conditioned air blown into the passenger compartment.

[0015] The temperature control system 100 can execute any one of a plurality of operation modes selected by the occupant or the control unit 30. In the present embodiment, as the operation modes of the temperature control system 100, a first heater mode (FIG. 1) in which only the first pump 21 operates, a second heater mode (FIG. 2) in which only the second pump 22 operates, a third heater mode (FIG. 3) in which both the first pump 21 and the second pump 22 operate, and a heat pump mode (FIG. 4) are exemplified.

[0016] <Configuration of Refrigerant Circuit 10> The refrigerant circuit 10 includes a compressor 11 that compresses the refrigerant RF, a condenser (high-pressure side heat exchanger) 12, an expansion valve (pressure reducing section) 13, an evaporator (low-pressure side heat exchanger) 14, and a pressure detection unit 15. In the refrigerant circuit 10, the refrigerant RF circulates according to the refrigeration cycle. As the refrigerant RF enclosed in the refrigerant circuit 10, a single refrigerant or a mixed refrigerant can be used. For example, HFC (Hydro Fluoro Carbon) refrigerants such as R410A and R32, HFO (Hydro Fluoro Olefin) refrigerants such as R1234ze and R1234yf, or hydrocarbon (HC)-based refrigerants such as propane and isobutane can be used. In particular, it is preferable to use R290 as the refrigerant in the present embodiment.

[0017] When using the fluorocarbon-based or hydrocarbon-based refrigerant listed above, a subcritical refrigeration cycle is configured in which the refrigerant pressure on the high-pressure side does not exceed the critical pressure of the refrigerant. When using carbon dioxide (CO2) as the refrigerant, a transcritical refrigeration cycle is configured in which the refrigerant pressure on the high-pressure side exceeds the critical pressure of the refrigerant. Even in that case, since the refrigerant dissipates heat by the high-pressure side heat exchanger in the same manner as the condenser 12 of the present embodiment, and the refrigerant absorbs heat by the low-pressure side heat exchanger in the same manner as the evaporator 14 of the present embodiment, a refrigerant that constitutes a transcritical refrigeration cycle such as carbon dioxide refrigerant can also be adopted in the refrigerant circuit 10.

[0018] The compressor 11 is, for example, an electric compressor equipped with an electric motor (not shown). The rotational speed of the compressor 11 is controlled by the control unit 30. As the compressor 11, for example, a scroll compressor or a rotary compressor is used.

[0019] The condenser 12 is a device that exchanges heat between the refrigerant RF discharged from the compressor 11 and the heat medium HM flowing through the heat medium circuit 20.

[0020] The expansion valve 13 reduces the pressure of the refrigerant RF flowing out from the condenser 12. As the expansion valve 13, in addition to an electronic expansion valve whose opening degree can be controlled based on a command from the control unit 30, a thermal expansion valve can be adopted. Note that a capillary tube may be adopted instead of the expansion valve 13. Further, a receiver (gas-liquid separator) (not shown) may be provided between the condenser 12 and the expansion valve 13.

[0021] The evaporator 14 is a device that exchanges heat between the refrigerant RF flowing out from the expansion valve 13 and the heat medium HM flowing through the heat medium circuit 20. The refrigerant RF evaporated by the evaporator 14 is guided to the suction side of the compressor 11. An accumulator (gas-liquid separator) (not shown) may be provided between the evaporator 14 and the compressor 11.

[0022] The pressure detection unit 15 is a device that detects the pressure of the refrigerant RF decompressed by the expansion valve 13. The pressure detection unit 15 detects, for example, the pressure of the refrigerant RF flowing between the evaporator 14 and the compressor 11.

[0023] The compressor 11, the condenser 12, the expansion valve 13, the evaporator 14, and the refrigerant pipes connecting these elements are installed, for example, outside the passenger compartment.

[0024] <Configuration of the heat medium circuit 20> The heat medium circuit 20 is configured such that a heat medium HM capable of exchanging heat with the refrigerant RF in the condenser 12 and the evaporator 14 can circulate. The heat medium HM is used for cooling or heating at least one temperature control target. In this embodiment, the temperature control target is the air supplied into the passenger compartment for air conditioning. Further, the temperature control target may be an in-vehicle battery device.

[0025] The heat medium HM enclosed in the heat medium circuit 20 is a liquid such as water or brine that circulates through the heat medium circuit 20 while maintaining a liquid phase state. Examples of brine include a mixed liquid of water and propylene glycol, or a mixed liquid of water and ethylene glycol.

[0026] The heat medium circuit 20 includes a first pump 21, a second pump 22, an outdoor heat exchanger 23, a reserve tank 24, an in-vehicle air conditioning unit (temperature control device) 25, a three-way valve (flow path branching portion) 26, a three-way valve 27, a three-way valve 28, and a three-way valve (flow path merging portion) 29.

[0027] As flow paths for circulating the heat medium HM, the heat medium circuit 20 has a first heat medium flow path L1 connecting the three-way valve 26 and the three-way valve 29 via the condenser 12, a second heat medium flow path L2 connecting the three-way valve 26 and the three-way valve 29 via the three-way valve 27, the evaporator 14, and the three-way valve 28, a third heat medium flow path L3 connecting the three-way valve 29 and the three-way valve 26 via the in-vehicle air conditioning unit 25, a fourth heat medium flow path L4 connecting the three-way valve 28 and the three-way valve 27 via the outdoor heat exchanger 23, and a communication flow path L5 communicating the first heat medium flow path L1 and the second heat medium flow path L2.

[0028] The starting, stopping, and rotational speed of the first pump 21 and the second pump 22 are controlled by the control unit 30.

[0029] The first pump 21 is a device that is arranged in the first heat medium flow path L1 and pumps the heat medium HM that has passed through the condenser 12 along the flow direction. The second pump 22 is a device that is arranged in the second heat medium flow path L2 and pumps the heat medium HM that has passed through the evaporator 14 along the flow direction.

[0030] The outdoor heat exchanger 23 is a device that is arranged in the fourth heat medium flow path L4 and exchanges heat between the outside air outside the passenger compartment and the heat medium. The outdoor heat exchanger 23 is arranged, for example, near the air inlet of the vehicle. The outside air supplied to the outdoor heat exchanger 23 by the running of the vehicle and the operation of the outdoor heat exchanger fan 23a radiates heat or absorbs heat based on the temperature difference between the outside air and the heat medium. The outside air temperature is detected by the temperature detection unit 23b.

[0031] The fourth heat medium flow path L4 is a flow path that branches the heat medium HM from the second heat medium flow path L2 on the downstream side in the flow direction of the heat medium HM from the evaporator 14 and allows the heat medium HM to flow into the second heat medium flow path L2 through the three-way valve 27 on the upstream side in the flow direction from the evaporator 14.

[0032] The communication flow path L5 is a flow path that connects the first position P1 on the downstream side in the flow direction from the condenser 12 of the first heat medium flow path L1 and the second position P2 on the downstream side in the flow direction from the evaporator 14 of the second heat medium flow path L2.

[0033] The reserve tank 24 is a device that is arranged in the communication flow path L5 and stores the heat medium HM. When the heat medium HM enclosed in the heat medium circuit 20 expands as the temperature rises, the reserve tank 24 receives the heat medium HM that exceeds the volume of the piping of the heat medium circuit 20 inside the tank.

[0034] Also, when the volume of the heat medium HM decreases as the temperature drops, the heat medium HM is replenished from the reserve tank 24 to the communication flow path L5, so the communication flow path L5 is maintained in a state filled with the heat medium HM. That is, the reserve tank 24 can prevent the internal pressure of the communication flow path L5 from becoming excessive or the inside of the communication flow path L5 from becoming a negative pressure. The inside of the reserve tank 24 is open to the atmosphere. Note that the reserve tank 24 may be sealed and adjusted to a desired constant pressure.

[0035] The indoor air conditioning unit 25 is a device that heats the air to be temperature-controlled using the heat medium HM by heat-exchanging the air sent by an indoor air conditioning fan (not shown) and the heat medium HM. The indoor air conditioning unit 25 supplies the air temperature-controlled in the vehicle interior by the indoor air conditioning fan. The temperature of the heat medium HM supplied to the indoor air conditioning unit 25 is detected by the temperature detection unit 25a.

[0036] The three-way valve 26 is arranged on the downstream side in the flow direction of the heat medium HM from the indoor air conditioning unit 25, and can branch the heat medium HM flowing in from the third heat medium flow path L3 into at least one of the first heat medium flow path L1 where the condenser 12 is arranged and the second heat medium flow path L2 where the evaporator 14 is arranged. The opening degree of the three-way valve 26 is controlled by the control unit 30, and according to the operation mode executed by the control unit 30, the state where the heat medium HM flowing in from the third heat medium flow path L3 flows only into the first heat medium flow path L1, the state where the heat medium HM flowing in from the third heat medium flow path L3 flows only into the second heat medium flow path L2, and the heat medium HM flowing in from the third heat medium flow path L3 flows into both the first heat medium flow path L1 and the second heat medium flow path L2. The connection direction is switched to any of the states. Also, the control unit 30 may have an operation mode in which the three-way valve 26 is fully closed and the heat medium HM does not flow in the third heat medium flow path L3, that is, a non-circulation state.

[0037] The three-way valve 27 is a device that switches between a circulating state in which the heat medium HM flows through the fourth heat medium flow path L4 and a non-circulating state in which the heat medium HM does not flow through the fourth heat medium flow path L4. The three-way valve 27 is controlled by the control unit 30 and can switch the connection direction or stop the flow of the heat medium HM according to the operation mode.

[0038] The three-way valve 28 is a device that switches between a circulating state in which the heat medium HM flows through the fourth heat medium flow path L4 and a non-circulating state in which the heat medium HM does not flow through the fourth heat medium flow path L4. The three-way valve 28 is controlled by the control unit 30 and can switch the connection direction or stop the flow of the heat medium HM according to the operation mode.

[0039] The three-way valve 29 is arranged upstream of the indoor air-conditioning unit 25 in the flow direction, and combines the heat medium HM flowing through the first heat medium flow path L1 and the heat medium HM flowing through the second heat medium flow path L2, and guides them to the indoor air-conditioning unit 25 through the third heat medium flow path L3.

[0040] <Configuration of the control unit 30> The control unit 30 is a device that controls the refrigerant circuit 10 and the heat medium circuit 20. The control unit 30 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. A series of processes for realizing various functions are stored in a storage medium or the like in the form of a program as an example. The CPU reads this program into the RAM or the like and executes information processing and arithmetic processing, thereby realizing various functions.

[0041] Note that the program may be applied 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. A computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, etc.

[0042] Next, the control of the temperature control system 100 with the above configuration will be described. <First heater mode for operating only the first pump 21: FIG. 1> The first heater mode for operating only the first pump 21 is suitable for heating when heat absorption from the outside air to the heat medium HM cannot be performed because the outside air temperature is low. In the heater mode, while avoiding heat dissipation from the heat medium HM to the outside air, a heat quantity corresponding to the power of the compressor 11 as a heat source is conveyed to the passenger compartment by the heat medium HM. Thereby, even in a situation where the outside air temperature is significantly lower than 0°C, the heating capacity can be ensured. In the heat medium circuit 20 shown in FIG. 1, the location where the heat medium HM flows is indicated by a thick dashed line, and the location where the heat medium HM does not flow is indicated by a thin dotted line.

[0043] In response to a command from the control unit 30, the refrigerant circuit 10 is activated. As a result, the refrigerant RF is compressed by the compressor 11 and the high-temperature and high-pressure refrigerant RF is supplied to the condenser 12. In the condenser 12, the refrigerant RF dissipates heat by exchanging heat with the heat medium HM, and the refrigerant RF condenses and liquefies. The liquefied high-pressure refrigerant RF is supplied to the evaporator 14 after being decompressed by the expansion valve 13.

[0044] In the evaporator 14, the refrigerant RF evaporates by obtaining the latent heat of vaporization by exchanging heat with the heat medium HM and becomes a low-pressure gaseous refrigerant RF. The refrigerant RF that has exited the evaporator 14 is guided to the compressor 11 and repeats the above-described refrigeration cycle.

[0045] The control unit 30 branches the heat medium HM into the first heat medium flow path L1 and the second heat medium flow path L2 with the three-way valve 26, and the heat medium HM that has passed through the condenser 12 disposed in the first heat medium flow path L1 and the heat medium HM that has passed through the evaporator 14 disposed in the second heat medium flow path L2 are merged at the first position P1 via the communication flow path L5. The heat medium HM merged at the first position P1 is supplied to the in-vehicle air-conditioning unit 25 disposed in the third heat medium flow path L3 via the three-way valve 29.

[0046] The heat medium HM flowing into the condenser 12 extracts heat from the refrigerant RF flowing through the condenser 12 and liquefies the refrigerant RF. The heat medium HM flowing into the evaporator 14 gives the latent heat of vaporization to the refrigerant RF flowing through the evaporator 14 to evaporate the refrigerant RF. The heat medium HM heated by the refrigerant RF in the condenser 12 provides heat to the air (or outside air) in the vehicle interior in the in-vehicle air-conditioning unit 25 to perform heating. The heat medium HM that has been cooled by providing heat is guided to the three-way valve 26.

[0047] The three-way valve 26 is configured to be able to adjust the first flow rate of the heat medium HM guided to the first heat medium flow path L1 and the second flow rate of the heat medium HM guided to the second heat medium flow path L2. The control unit 30 controls the three-way valve 26 to adjust the first flow rate and the second flow rate, for example, based on the pressure and / or temperature of the refrigerant RF flowing into the evaporator 14. When the control unit 30 increases the pressure of the refrigerant RF flowing into the evaporator 14, the control unit 30 controls the three-way valve 26 so that the second flow rate increases.

[0048] Also, the control unit 30 controls the three-way valve 26 to adjust the first flow rate and the second flow rate, for example, based on the pressure and / or temperature of the refrigerant RF flowing into the condenser 12. When the control unit 30 increases the pressure of the refrigerant RF flowing into the condenser 12, the control unit 30 controls the three-way valve 26 so that the second flow rate increases.

[0049] As described above, the control unit 30 operates only the first pump 21 without operating the second pump 22, and controls the refrigerant circuit 10, the three-way valve 26, the three-way valve 27, the three-way valve 29, and the first pump 21 so as to execute a heater mode in which the heat medium HM that has passed through the condenser 12 and the evaporator 14 is supplied to the in-vehicle air-conditioning unit 25.

[0050] <Second heater mode of operating only the second pump 22: Figure 2> The second heater mode that operates only the second pump 22 is suitable for heating when heat cannot be absorbed from the outside air because the outside air temperature is low. The heater mode conveys an amount of heat corresponding to the power of the compressor 11 as a heat source to the passenger compartment by the heat medium HM while avoiding heat dissipation from the heat medium HM to the outside air. Thereby, the heating capacity can be ensured even in a situation where the outside air temperature is significantly lower than 0°C. In the heat medium circuit 20 shown in FIG. 2, the locations where the heat medium HM flows are indicated by thick dashed lines, and the locations where the heat medium HM does not flow are indicated by thin dotted lines.

[0051] The second heater mode that operates only the second pump 22 shown in FIG. 2 is different from the first heater mode that operates only the first pump 21 shown in FIG. 1 in that the second pump 22 is operated instead of the first pump 21.

[0052] The control unit 30 branches the heat medium HM into the first heat medium flow path L1 and the second heat medium flow path L2 with the three-way valve 26, and combines the heat medium HM that has passed through the condenser 12 arranged in the first heat medium flow path L1 and the heat medium HM that has passed through the evaporator 14 arranged in the second heat medium flow path L2 at the second position P2 via the communication flow path L5. The heat medium HM that has merged at the second position P2 is supplied to the in-vehicle air-conditioning unit 25 arranged in the third heat medium flow path L3 via the three-way valve 28 and the three-way valve 29.

[0053] As described above, the control unit 30 controls the refrigerant circuit 10, the three-way valve 26, the three-way valve 27, the three-way valve 28, the three-way valve 29, and the second pump 22 to execute a heater mode in which only the second pump 22 is operated without operating the first pump 21, and the heat medium HM that has passed through the condenser 12 and the evaporator 14 is supplied to the in-vehicle air-conditioning unit 25.

[0054] <The third heater mode that operates both the first pump 21 and the second pump 22: FIG. 3> The third heater mode that operates both the first pump 21 and the second pump 22 is suitable for heating when heat cannot be absorbed from the outside air into the heat medium HM because the outside air temperature is low. The heater mode conveys an amount of heat corresponding to the power of the compressor 11 as a heat source to the passenger compartment by the heat medium HM while avoiding heat dissipation from the heat medium HM to the outside air. Thereby, the heating capacity can be ensured even in a situation where the outside air temperature is significantly lower than 0°C. In the heat medium circuit 20 shown in FIG. 3, the locations where the heat medium HM flows are indicated by thick dashed lines, and the locations where the heat medium HM does not flow are indicated by thin dotted lines.

[0055] The third heater mode that operates both the first pump 21 and the second pump 22 shown in FIG. 3 is different from the first heater mode that operates only the first pump 21 shown in FIG. 1 in that not only the first pump 21 but also the second pump 22 operates.

[0056] The control unit 30 branches the heat medium HM into the first heat medium flow path L1 and the second heat medium flow path L2 with the three-way valve 26, and combines a part of the heat medium HM that has passed through the condenser 12 arranged in the first heat medium flow path L1 and a part of the heat medium HM that has passed through the evaporator 14 arranged in the second heat medium flow path L2 at the first position P1 via the communication flow path L5.

[0057] Note that the heat medium HM may be branched into the first heat medium flow path L1 and the second heat medium flow path L2 with the three-way valve 26, and a part of the heat medium HM that has passed through the condenser 12 arranged in the first heat medium flow path L1 and the heat medium HM that has passed through the evaporator 14 arranged in the second heat medium flow path L2 may be combined at the second position P2 via the communication flow path L5.

[0058] Another part of the heat medium HM that has passed through the evaporator 14 arranged in the second heat medium flow path L2 is guided to the three-way valve 28 via the second pump 22. The heat medium HM that passes through the first pump 21 and the heat medium HM that passes through the second pump 22 merge at the three-way valve 29 and are supplied to the in-vehicle air-conditioning unit 25 arranged in the third heat medium flow path L3.

[0059] Note that another part of the heat medium HM that has passed through the condenser 12 disposed in the first heat medium flow path L1 is guided to the three-way valve 29 via the first pump 21. The heat medium HM passing through the second pump 22 and the heat medium HM passing through the first pump 21 may merge at the three-way valve 29 and be supplied to the in-vehicle air-conditioning unit 25 disposed in the third heat medium flow path L3.

[0060] As described above, the control unit 30 operates both the first pump 21 and the second pump 22, and controls the refrigerant circuit 10, the three-way valves 26, 27, 28, 29, the first pump 21, and the second pump 22 so as to execute a third heater mode in which the heat medium HM that has passed through the condenser 12 and the evaporator 14 is supplied to the in-vehicle air-conditioning unit 25.

[0061] When the control unit 30 executes the third heater mode in which both the first pump 21 and the second pump 22 are operated, the control unit 30 may control the first pump 21 and the second pump 22 so that the second flow rate of the heat medium HM passing through the evaporator 14 is larger than the first flow rate of the heat medium HM passing through the condenser 12. By doing so, the amount of heat exchange between the heat medium HM and the refrigerant RF in the evaporator 14 can be increased, and the low pressure in the refrigerant circuit 10 can be increased. As a result, the refrigerant circulation amount can be increased by increasing the suction refrigerant density of the compressor 11, and the heating capacity of the in-vehicle air-conditioning unit 25 can be improved.

[0062] <Heat pump mode: FIG. 4> In the heat pump mode, heat is drawn from the outside air as a heat source to heat the vehicle interior. The operation of the refrigerant circuit 10 is the same as that in the heater mode shown in FIG. 1, and thus the description thereof is omitted.

[0063] The heat medium HM heated by the refrigerant RF in the condenser 12 is guided to the third heat medium flow path L3 through the first heat medium flow path L1 by the action of the first pump 21. Then, the heat medium HM warms the air (or outside air) in the vehicle interior guided from the in-vehicle air-conditioning unit 25. The heat medium HM that has been cooled after giving warmth is guided to the three-way valve 26.

[0064] The control unit 30 forms the first circulation system by guiding the heat medium HM from the third heat medium flow path L3 only to the first heat medium flow path L1 with the three-way valve 26 and guiding the heat medium HM that has passed through the first heat medium flow path L1 to the indoor air conditioning unit 25 with the three-way valve 29. Further, the control unit 30 forms the second circulation system by guiding the heat medium HM from the second heat medium flow path L2 to the fourth heat medium flow path L4 with the three-way valves 27 and 28.

[0065] By forming the first circulation system and the second circulation system, the control unit 30 heats the heat medium HM with the outside air in the outdoor heat exchanger 23, heats the refrigerant RF with the heat medium HM passing through the second heat medium flow path L2, and heats the heat medium HM passing through the first heat medium flow path L1 with the refrigerant RF, and controls the three-way valves 26, 27, 28, 29, the first pump 21, and the second pump 22 so as to execute the heat pump mode.

[0066] <Switching operation of the heating operation mode> Next, with reference to FIGS. 5 and 6, the switching operation of the heating operation mode will be described. FIG. 5 is a flowchart showing a process in which the temperature control system 100 according to an embodiment of the present disclosure executes a heating operation. FIG. 6 is a flowchart showing a process of switching between and executing the first heater mode and the second heater mode. The control unit 30 executes the heating operation by switching between the first heater mode, the second heater mode, the third heater mode, and the heat pump mode according to the processes shown in FIGS. 5 and 6.

[0067] Here, the first heater mode is a heater mode in which only the first pump 21 shown in FIG. 1 is operated. The second heater mode is a heater mode in which only the second pump 22 shown in FIG. 2 is operated. The third heater mode is a heater mode in which both the first pump 21 and the second pump 22 shown in FIG. 3 are operated.

[0068] In step S101, the control unit 30 determines whether the outside air temperature detected by the temperature detection unit 23b is equal to or lower than a predetermined outside air temperature at which heating operation by the heat pump mode is impossible. If YES, the process proceeds to step S102; if NO, the process proceeds to step S107. Note that not only the outside air temperature but also whether heating operation by the heat pump mode is impossible may be determined based on the outside air temperature and the required heating capacity.

[0069] In step S102, the control unit 30 determines whether the temperature of the heat medium HM detected by the temperature detection unit 25a is equal to or higher than a predetermined temperature. If YES, the process proceeds to step S103; if NO, the process proceeds to step S108.

[0070] In step S103, the control unit 30 determines whether the pressure of the refrigerant RF detected by the pressure detection unit 15 is equal to or higher than a predetermined pressure. If YES, the process proceeds to step S104; if NO, the process proceeds to step S108.

[0071] In step S104, the control unit 30 determines whether the amount of heat required by the indoor air conditioning unit 25 is equal to or lower than a predetermined value. If YES, the process proceeds to step S105; if NO, the process proceeds to step S108. The temperature control system 100 includes a setting unit 35 that sets the amount of heat required by the indoor air conditioning unit 25 (for example, the target temperature inside the vehicle cabin). The control unit 30 executes step S105 when the amount of heat set by the setting unit 35 is equal to or lower than the predetermined value, and executes step S108 when the amount of heat set by the setting unit 35 is greater than the predetermined value.

[0072] In step S105, the control unit 30 controls the temperature control system 100 to execute the first heater mode or the second heater mode. The control unit 30 executes either the first heater mode in which only the first pump 21 shown in FIG. 1 is operated or the second heater mode in which only the second pump 22 shown in FIG. 2 is operated.

[0073] Here, referring to FIG. 6, the process of switching between and executing the first heater mode and the second heater mode in step S105 will be described.

[0074] In step S201, the control unit 30 compares a first integrated time obtained by integrating the time during which the first pump 21 operates in a predetermined operating state with a second integrated time obtained by integrating the time during which the second pump 22 operates in a predetermined operating state. When the first integrated time is less than or equal to the second integrated time, the control unit 30 proceeds to step S202, and when the first integrated time is longer than the second integrated time, the control unit 30 proceeds to step S203.

[0075] Here, the predetermined operating state refers to, for example, an operating state in which the first pump 21 or the second pump 22 operates at a rotation speed equal to or higher than a predetermined rotation speed (e.g., 60% or more of the maximum rotation speed) per unit time. Also, the predetermined operating state may be an operating state in which the first pump 21 or the second pump 22 operates at any rotation speed greater than 0 per unit time.

[0076] Here, the control unit 30 may calculate an operation value by weighting the operation time during which the pump rotation speed is higher than the predetermined rotation speed with respect to the operation time during which the pump rotation speed is lower than the predetermined rotation speed, and calculate a cumulative operation value by integrating the operation values of the first pump 21 and the second pump 22. In this case, when the cumulative operation value of the second pump 22 is greater than the cumulative operation value of the first pump 21, the control unit 30 executes the first heater mode, and when the cumulative operation value of the first pump 21 is greater than the cumulative operation value of the second pump 22, the control unit 30 executes the second heater mode. In this way, the total value of the pump rotation speed × operation value (a value obtained by weighting the operation time) may be used as the cumulative operation value, and the pump with the smaller cumulative operation value may be operated.

[0077] In step S202, the control unit 30 controls the temperature control system 100 to execute the first heater mode. The control unit 30 executes the first heater mode in which only the first pump 21 shown in FIG. 1 operates.

[0078] In step S203, the control unit 30 controls the temperature control system 100 to execute the second heater mode. The control unit 30 executes the second heater mode in which only the second pump 22 shown in FIG. 2 operates.

[0079] In step S106, the control unit 30 determines whether to end the heating operation. If YES, the process of this flowchart is ended. If NO, step S101 is executed again.

[0080] In step S107, the control unit 30 controls the temperature control system 100 to execute the heat pump mode shown in FIG. 4.

[0081] In step S108, the control unit 30 controls the temperature control system 100 to execute the third heater mode. The control unit 30 executes the third heater mode in which both the first pump 21 and the second pump 22 shown in FIG. 3 operate.

[0082] The temperature control system 100 of the present embodiment described above has the following operations and effects. According to the temperature control system 100 of the present embodiment, as a heater mode for supplying the heat medium HM heated by the power of the compressor 11 to the indoor air conditioning unit 25 at a low outside air temperature, the first heater mode and the second heater mode can be switched and executed. Therefore, compared with the case where only one of the first heater mode or the second heater mode is executed, an excessive load is prevented from being applied to either the first pump 21 or the second pump 22, and the life of the temperature control system can be extended.

[0083] According to the temperature control system 100 of the present embodiment, for example, when the temperature of the heat medium HM supplied to the indoor air conditioning unit 25 is equal to or higher than a predetermined temperature, or when the circulation amount of the heat medium HM circulated through the indoor air conditioning unit 25 may be relatively small, by executing the first heater mode or the second heater mode, the heat dissipation amount to the outside air can be reduced compared with the case where both the first pump 21 and the second pump 22 operate.

[0084] Further, according to the temperature control system 100 of the present embodiment, for example, when the temperature of the heat medium HM supplied to the indoor air-conditioning unit 25 is lower than a predetermined temperature, or when a relatively large circulation amount of the heat medium HM circulated through the indoor air-conditioning unit 25 is required, by executing the third heater mode, the heating performance can be improved as compared with the case where only one of the first pump 21 and the second pump 22 is operated.

[0085] According to the temperature control system 100 of the present embodiment, when the second integration time is longer than the first integration time and the first heater mode is performed, the first pump 21, which operates for a shorter time and has a smaller load in a predetermined operating state, is preferentially operated over the second pump 22, which operates for a longer time and has a larger load in the predetermined operating state, thereby preventing the second pump 22 from failing. Further, when the first integration time is longer than the second integration time and the second heater mode is performed, the second pump 22, which operates for a shorter time and has a smaller load in a predetermined operating state, is preferentially operated over the first pump 21, which operates for a longer time and has a larger load in the predetermined operating state, thereby preventing the first pump 21 from failing.

[0086] According to the temperature control system 100 of the present embodiment, an operation value is calculated by weighting the operation time during which the pump rotation speed is higher than the predetermined rotation speed with respect to the operation time during which the pump rotation speed is lower than the predetermined rotation speed, and by comparing the cumulative operation value of the first pump and the cumulative operation value of the second pump, it is possible to appropriately switch which of the first heater mode and the second heater mode is to be executed. Thereby, the pump with less cumulative operation state can be operated to extend the life of the temperature control system.

[0087] According to the temperature control system 100 of the present embodiment, by alternately executing the first heater mode and the second heater mode at predetermined intervals, it is possible to appropriately prevent an excessive load from being applied to only one of the first pump 21 and the second pump 22, causing a failure.

[0088] 〔Modification example〕 In the above description, in step S105 of FIG. 5, the first integrated time obtained by integrating the time during which the first pump 21 operates in a predetermined operating state and the second integrated time obtained by integrating the time during which the second pump 22 operates in a predetermined operating state are compared, and either the first heater mode or the second heater mode is executed. However, other embodiments may also be possible.

[0089] For example, as a modification, the first heater mode and the second heater mode may be alternately executed at predetermined intervals. By alternately executing the first heater mode and the second heater mode at predetermined intervals, it is possible to appropriately prevent an excessive load from being applied to only one of the first pump 21 and the second pump 22 and causing a failure.

[0090] Note that the start of the heater mode is counted as one time. That is, when the first heater mode is started and then terminated and switched to another operation mode, the first heater mode is considered to have been executed once, and when the second heater mode is started and then terminated and switched to another operation mode, the second heater mode is considered to have been executed once.

[0091] In the above description, the first pump 21 is arranged in the first heat medium flow path L1 on the downstream side of the first position P1 in the flow direction of the heat medium HM, and the second pump 22 is arranged in the second heat medium flow path L2 on the downstream side of the second position P2 in the flow direction of the heat medium HM. However, other embodiments may also be possible. For example, the first pump 21 may be arranged at an arbitrary position on the downstream side of the three-way valve 29 and on the upstream side of the three-way valve 26 in the flow direction of the heat medium HM, and the second pump 22 may be arranged at an arbitrary position on the downstream side of the three-way valve 28 and on the upstream side of the three-way valve 27 in the flow direction of the heat medium HM.

[0092] In the above description, the indoor air-conditioning unit 25 is arranged in the third heat medium flow path L3, but other embodiments may also be possible. For example, the indoor air-conditioning unit 25 may be arranged at an arbitrary position between the condenser 12 of the first heat medium flow path L1 and the first position P1. In this case, when the heater mode is executed, since the heat medium HM that is cooled by heat exchange with the refrigerant RF when passing through the evaporator 14 is not supplied to the indoor air-conditioning unit 25, the heat of the heat medium HM that heats the air in the indoor air-conditioning unit 25 is not cooled by other heat media HM. Therefore, it is possible to improve the heating start-up performance when executing the heater mode of supplying the heat medium HM heated by the power of the compressor 11 to the indoor air-conditioning unit 25 at low outside air temperatures.

[0093] The temperature control system and the method for controlling the temperature control system according to each of the embodiments described above are understood as follows, for example.

[0094] The temperature control system according to the first aspect of the present disclosure includes a refrigerant circuit (10) through which a refrigerant circulates, the refrigerant circuit including a compressor (11), a high-pressure side heat exchanger (12), a decompression unit (13), and a low-pressure side heat exchanger (14); a heat medium circuit (20) 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 (30) that controls the refrigerant circuit and the heat medium circuit. The heat medium circuit includes a temperature control device (25) that heats a temperature control target using the heat medium, a flow path branching unit (26) that is disposed downstream of the temperature control device in the flow direction of the heat medium and guides the heat medium to at least one of a first heat medium flow path (L1) that guides the heat medium to the high-pressure side heat exchanger and a second heat medium flow path (L2) that guides the heat medium to the low-pressure side heat exchanger, a flow path merging unit (29) that is disposed upstream of the temperature control device in the flow direction and merges the heat medium flowing through the first heat medium flow path and the heat medium flowing through the second heat medium flow path and guides the merged heat medium to the temperature control device, a first pump (21) that is disposed in the first heat medium flow path and pumps the heat medium that has passed through the high-pressure side heat exchanger along the flow direction, a second pump (22) that is disposed in the second heat medium flow path and pumps the heat medium that has passed through the low-pressure side heat exchanger along the flow direction, and a communication flow path (L5) that communicates a downstream side of the high-pressure side heat exchanger in the flow direction of the first heat medium flow path and a downstream side of the low-pressure side heat exchanger in the flow direction of the second heat medium flow path. The control unit switches between and executes a first heater mode in which only the first pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communication flow path and supply the merged heat medium to the temperature control device, and a second heater mode in which only the second pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communication flow path and supply the merged heat medium to the temperature control device.

[0095] According to the temperature control system according to the first aspect of the present disclosure, as a heater mode for supplying a heat medium heated by the power of a compressor to a temperature control device at a low outside air temperature, the first heater mode and the second heater mode can be switched and executed. Therefore, compared with the case where only one of the first heater mode or the second heater mode is executed, an excessive load is prevented from being applied to either the first pump or the second pump, and the life of the temperature control system can be extended.

[0096] The temperature control system according to the second aspect of the present disclosure further includes the following configuration in the first aspect. That is, the control unit switches and executes the first heater mode, the second heater mode, and a third heater mode in which both the first pump and the second pump are operated to combine the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger at the flow path merging portion and supply the combined heat medium to the temperature control device.

[0097] According to the temperature control system according to the second aspect of the present disclosure, for example, when the temperature of the heat medium supplied to the temperature control device is equal to or higher than a predetermined temperature, or when the circulation amount of the heat medium circulated through the temperature control device may be relatively small, by executing the first heater mode or the second heater mode, the heat dissipation amount to the outside air can be reduced compared with the case where both the first pump and the second pump are operated.

[0098] Also, according to the temperature control system according to the second aspect of the present disclosure, for example, when the temperature of the heat medium supplied to the temperature control device is lower than a predetermined temperature, or when the circulation amount of the heat medium circulated through the temperature control device is required to be relatively large, by executing the third heater mode, the heating performance can be improved compared with the case where only one of the first pump and the second pump is operated.

[0099] The temperature control system according to the third aspect of the present disclosure further includes the following configuration in the first aspect or the second aspect. That is, when the second integrated time obtained by integrating the time during which the second pump operates in the predetermined operating state is longer than the first integrated time obtained by integrating the time during which the first pump operates in the predetermined operating state, the control unit executes the first heater mode, and when the first integrated time is longer than the second integrated time, the control unit executes the second heater mode.

[0100] According to the temperature control system according to the third aspect of the present disclosure, when the second integrated time is longer than the first integrated time, by performing the first heater mode, the first pump that operates for a shorter time and has a smaller load in the predetermined operating state is preferentially operated over the second pump that operates for a longer time and has a larger load in the predetermined operating state, thereby preventing the second pump from failing. Further, when the first integrated time is longer than the second integrated time, by performing the second heater mode, the second pump that operates for a shorter time and has a smaller load in the predetermined operating state is preferentially operated over the first pump that operates for a longer time and has a larger load in the predetermined operating state, thereby preventing the first pump from failing.

[0101] The temperature control system according to the fourth aspect of the present disclosure further includes the following configuration in the first aspect or the second aspect. That is, an operation value is calculated by weighting the operation time during which the pump rotation speed is higher than the predetermined rotation speed with respect to the operation time during which the pump rotation speed is lower than the predetermined rotation speed, the operation values of the first pump and the second pump are integrated to calculate a cumulative operation value, the first heater mode is executed when the cumulative operation value of the second pump is larger than the cumulative operation value of the first pump, and the second heater mode is executed when the cumulative operation value of the first pump is larger than the cumulative operation value of the second pump.

[0102] According to the temperature control system according to the fourth aspect of the present disclosure, an operation value is calculated by weighting the operation time in which the pump rotation speed is higher than the predetermined rotation speed with respect to the operation time in which the pump rotation speed is lower than the predetermined rotation speed, and the cumulative operation value of the first pump and the cumulative operation value of the second pump are compared to appropriately switch between executing the first heater mode and the second heater mode.

[0103] The temperature control system according to the fifth aspect of the present disclosure further includes the following configuration in the first aspect or the second aspect. That is, the control unit alternately executes the first heater mode and the second heater mode every predetermined number of times.

[0104] According to the temperature control system according to the fifth aspect of the present disclosure, by alternately executing the first heater mode and the second heater mode every predetermined number of times, it is possible to appropriately prevent an excessive load from being applied to only one of the first pump or the second pump and causing a failure.

[0105] In the control method of the temperature control system according to the sixth aspect of the present disclosure, the temperature control system includes a refrigerant circuit in which a refrigerant circulates through a compressor, a high-pressure side heat exchanger, a decompression unit, and a low-pressure side heat exchanger, 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 heats a temperature control target using the heat medium, a flow path branching unit that is disposed downstream of the temperature control device in the flow direction of the heat medium and guides the heat medium to at least one of a first heat medium flow path that guides the heat medium to the high-pressure side heat exchanger and a second heat medium flow path that guides the heat medium to the low-pressure side heat exchanger, a flow path merging unit that is disposed upstream of the temperature control device in the flow direction and merges the heat medium flowing through the first heat medium flow path and the heat medium flowing through the second heat medium flow path, a first pump that is disposed in the first heat medium flow path and pumps the heat medium that has passed through the high-pressure side heat exchanger along the flow direction, a second pump that is disposed in the second heat medium flow path and pumps the heat medium that has passed through the low-pressure side heat exchanger along the flow direction, and a communication flow path that communicates a downstream side of the high-pressure side heat exchanger in the flow direction of the first heat medium flow path and a downstream side of the low-pressure side heat exchanger in the flow direction of the second heat medium flow path. The control step includes controlling the refrigerant circuit and the heat medium circuit so as to switch between and execute a first heater mode in which only the first pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communication flow path and supply the merged heat medium to the temperature control device, and a second heater mode in which only the second pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communication flow path and supply the merged heat medium to the temperature control device.

[0106] According to the control method of the temperature control system according to the sixth aspect of the present disclosure, as a heater mode for supplying the heat medium heated by the power of the compressor to the temperature control device at low outside air temperature, the first heater mode and the second heater mode can be switched and executed. Therefore, compared with the case where only one of the first heater mode or the second heater mode is executed, an excessive load is prevented from being applied to either the first pump or the second pump, and the life of the temperature control system can be extended.

Description of Symbols

[0107] 10 Refrigerant circuit 11 Compressor 12 Condenser (High-pressure side heat exchanger) 13 Expansion valve (Pressure reducing section) 14 Evaporator (Low-pressure side heat exchanger) 15 Pressure detection section 20 Heat medium circuit 21 First pump 22 Second pump 23 Outdoor heat exchanger 23a Outdoor heat exchanger fan 23b Temperature detection section 24 Reservoir tank 25 Indoor air conditioning unit (Temperature control device) 25a Temperature detection section 26 Three-way valve (Flow path branching section) 27, 28 Three-way valves 29 Three-way valve (Flow path merging section) 30 Control section 35 Setting section 100 Temperature control system HM Heat medium L1 First heat medium flow path L2 Second heat medium flow path L3 Third heat medium flow path L4 Fourth heat medium flow path L5 Communication flow path P1 First position P2 Second position RF Refrigerant

Claims

1. a refrigerant circuit in which a refrigerant circulates through a compressor, a high-pressure side heat exchanger, a pressure reducing section, and a low-pressure side heat exchanger; a heat medium circuit through which a heat medium circulates to exchange heat with the 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 heats a temperature control target using the heat medium; a flow path branch portion that is disposed downstream of the temperature control device in a flow direction of the heat medium and that guides the heat medium to at least one of a first heat medium flow path that guides the heat medium to the high-pressure side heat exchanger and a second heat medium flow path that guides the heat medium to the low-pressure side heat exchanger; a flow path junction portion that is disposed upstream of the temperature control device in the flow direction and joins the heat medium flowing through the first heat medium flow path and the heat medium flowing through the second heat medium flow path to guide the heat medium to the temperature control device; a first pump disposed in the first heat medium flow path and configured to pump the heat medium that has passed through the high-pressure side heat exchanger along the flow direction; a second pump disposed in the second heat medium flow path and configured to pump the heat medium that has passed through the low-pressure side heat exchanger along the flow direction; a communication flow path that communicates a downstream side of the high-pressure side heat exchanger of the first heat medium flow path in the flow direction with a downstream side of the low-pressure side heat exchanger of the second heat medium flow path in the flow direction, The control unit switches between a first heater mode in which only the first pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communicating flow path and supply it to the temperature control equipment, and a second heater mode in which only the second pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communicating flow path and supply it to the temperature control equipment.

2. The temperature control system of claim 1, wherein the control unit switches between the first heater mode, the second heater mode, and a third heater mode in which the control unit operates both the first pump and the second pump to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger at the flow path junction and supply them to the temperature control equipment.

3. 3. The temperature control system according to claim 1, wherein the control unit executes the first heater mode when a second accumulated time obtained by accumulating the time during which the second pump operates in a specified operating state is longer than a first accumulated time obtained by accumulating the time during which the first pump operates in the specified operating state, and executes the second heater mode when the first accumulated time is longer than the second accumulated time.

4. The temperature control system of claim 1 or claim 2, wherein the control unit calculates an operation value by weighting operation time when the pump rotation speed is higher than a predetermined rotation speed against operation time when the pump rotation speed is lower than the predetermined rotation speed, calculates a cumulative operation value by integrating the operation values ​​of the first pump and the second pump, executes the first heater mode when the cumulative operation value of the second pump is greater than the cumulative operation value of the first pump, and executes the second heater mode when the cumulative operation value of the first pump is greater than the cumulative operation value of the second pump.

5. The temperature adjustment system according to claim 1 or 2, wherein the control unit alternately executes the first heater mode and the second heater mode a predetermined number of times.

6. A method for controlling a temperature adjustment system, comprising: The temperature control system includes: a refrigerant circuit in which a refrigerant circulates through a compressor, a high-pressure side heat exchanger, a pressure reducing section, and a low-pressure side heat exchanger; a heat medium circuit through which a heat medium circulates to exchange heat with the 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 heats a temperature control target using the heat medium; a flow path branch portion that is disposed downstream of the temperature control device in a flow direction of the heat medium and that guides the heat medium to at least one of a first heat medium flow path that guides the heat medium to the high-pressure side heat exchanger and a second heat medium flow path that guides the heat medium to the low-pressure side heat exchanger; a flow path junction portion that is disposed upstream of the temperature control device in the flow direction and that joins the heat medium flowing through the first heat medium flow path and the heat medium flowing through the second heat medium flow path; a first pump disposed in the first heat medium flow path and configured to pump the heat medium that has passed through the high-pressure side heat exchanger along the flow direction; a second pump disposed in the second heat medium flow path and configured to pump the heat medium that has passed through the low-pressure side heat exchanger along the flow direction; a communication flow path that communicates a downstream side of the high-pressure side heat exchanger of the first heat medium flow path in the flow direction with a downstream side of the low-pressure side heat exchanger of the second heat medium flow path in the flow direction, A control method for a temperature adjustment system comprising a control step of controlling the refrigerant circuit and the heat medium circuit to switch between a first heater mode in which only the first pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communicating flow path and supply the heat medium to the temperature adjustment device, and a second heater mode in which only the second pump is operated to merge the heat medium that has passed through the high-pressure side heat exchanger and the heat medium that has passed through the low-pressure side heat exchanger via the communicating flow path and supply the heat medium to the temperature adjustment device.

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