Temperature control system and control method thereof

Abstract

To provide a temperature control system that can switch a flow passage of a heat medium with a simple configuration.SOLUTION: A temperature control system 1A includes: a refrigerant circuit 10; and a heat medium circuit 20 in which a heat medium that exchanges heat with a refrigerant circulates in a condenser 12 and an evaporator 14. The heat medium circuit 20 has an outdoor heat exchanger 23, a second indoor heat exchanger 25c, a reserve tank 58 for storing the heat medium, a first pump 21 having a suction section 21a connected to one side across the reserve tank 58, a second pump 22 having a suction section 22a connected to the other side across the reserve tank 58, a connection valve 48 which is provided in an evaporator outlet pipe 44 and connects a heat medium outflow side of the evaporator 14 with the second pump 22, and a condenser supply pipe 54 connecting the connection valve 48 with the heat medium inflow side of the condenser 12. The connection valve 48 can adjust a flow in a first direction, in which the heat medium is supplied in a direction of the second pump 22, and a second direction, in which the heat medium is supplied to the condenser supply pipe 54.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] In vehicles such as electric vehicles and so-called hybrid vehicles that obtain driving force for running from an engine and an electric motor, heat sources tend to be insufficient, and in addition to air conditioning functions required for vehicles such as heating and cooling, dehumidification, and ventilation, thermal management of on-board devices such as batteries and utilization of exhaust heat are required. In response to such requirements, in addition to heat pump systems, a number of systems have been used, including systems that include chillers that cool batteries and heaters that heat batteries, and systems that transport water heated by exhaust heat from the running motor to a temperature-controlled object using a pump.

[0003] A proposed vehicle thermal management system includes a primary loop in which a refrigerant circulates according to a refrigeration cycle, and a secondary loop in which a heat medium (such as water) is transported to an interior air conditioning unit by a pump (see Patent Document 1).

[0004] Patent Document 1 discloses an invention that uses cooling water (heat medium) to cool electrical equipment and a battery. That is, the invention includes a cooling water line in which cooling water supplied from a reserve tank that stores cooling water to electrical equipment circulates, and another cooling water line in which cooling water supplied from the same reserve tank to a battery circulates. Each cooling water line is provided with a pump and a switching valve, and either or both of the electrical equipment and the battery are cooled depending on the open / closed state of the switching valve. The reserve tank receives the excess heat medium when the volume of the heat medium increases due to a temperature rise, and replenishes the heat medium into the piping when the temperature drops. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6064753 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, a switching valve having five ports is used to switch the flow path of the cooling water. However, when considering the cost and reliability of the system, it is preferable to be able to switch the cooling water with as simple a configuration as possible.

[0007] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a temperature adjustment system capable of switching the flow path of a heat medium with a simple configuration, and a control method thereof. [Means for solving the problem]

[0008] A temperature control system according to one aspect of the present disclosure includes a refrigerant circuit in which a refrigerant circulates through a compressor, a high-pressure side heat exchanger, a pressure reducing unit, and a low-pressure side heat exchanger, and a heat medium circuit in 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 an outdoor heat exchanger that exchanges heat between outdoor air and the heat medium, a temperature control device that uses the heat medium to heat or cool a temperature control target, a reserve tank that stores the heat medium, and a suction unit that is connected to one side of the reserve tank and supplies the heat medium. the heat medium supply pipe connecting the connection valve and the heat medium inlet side of the high pressure side heat exchanger, the connection valve being provided in a pipe for the second pump connecting the heat medium outlet side of the low pressure side heat exchanger and the second pump, and the connection valve being capable of adjusting the flow between a first direction for supplying the heat medium towards the second pump and a second direction for supplying the heat medium to the heat medium high pressure side supply pipe.

[0009] A method for controlling a temperature adjustment system according to one aspect of the present disclosure includes a refrigerant circuit in which a refrigerant circulates through a compressor, a high-pressure side heat exchanger, a pressure reducing unit, and a low-pressure side heat exchanger, and a heat medium circuit in 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 including an outdoor heat exchanger for heat exchange between outdoor air and the heat medium, a temperature adjustment device for heating or cooling a temperature adjustment target using the heat medium, a reserve tank for storing the heat medium, and a second intake unit for transporting the heat medium, the second intake unit being connected to one side of the reserve tank and configured to receive the heat medium. A control method for a temperature adjustment system including a first pump, a second pump having an inlet connected to the other side of the reserve tank and transporting a heat medium, a connection valve provided in a second pump piping connecting a heat medium outlet side of the low-pressure side heat exchanger and the second pump, and a high-pressure side heat medium supply piping connecting the connection valve and the heat medium inlet side of the high-pressure side heat exchanger, wherein the connection valve is used to adjust the flow of the heat medium in a first direction toward the second pump and a second direction toward the high-pressure side heat medium supply piping. Effect of the Invention

[0010] The flow path of the heat medium can be switched with a simple configuration. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic configuration diagram of a temperature adjustment system according to a first embodiment of the present disclosure, illustrating a cooling mode. [Diagram 2] 2 is a schematic diagram showing the configuration of the temperature adjustment system in FIG. 1 in a heat pump mode. [Diagram 3] 2 is a schematic diagram showing a heater mode of the temperature adjustment system of FIG. 1. FIG. [Figure 4] FIG. 4 is a schematic configuration diagram showing a modified example of the first embodiment. [Diagram 5] FIG. 11 is a schematic configuration diagram of a temperature adjustment system according to a second embodiment of the present disclosure, showing a heater mode. [Figure 6] FIG. 11 is a schematic configuration diagram showing a modified example of the second embodiment. [Figure 7]FIG. 11 is a schematic configuration diagram of a temperature adjustment system according to a third embodiment of the present disclosure, showing a heater mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [First embodiment] Hereinafter, a first embodiment of the present disclosure will be described with reference to FIG. The vehicle temperature adjustment system 1A shown in Fig. 1 is installed in a vehicle (not shown), such as an electric vehicle that does not have an engine and obtains driving force for running the vehicle from an electric motor for running, or a so-called hybrid vehicle that obtains driving force for running the vehicle from an engine and an electric motor. The temperature adjustment system 1A is responsible for air conditioning such as heating / cooling, dehumidification, and ventilation of the passenger compartment 8 in which the occupants sit, as well as thermal management and exhaust heat recovery of on-board devices such as a battery device (power supply device) mounted on the vehicle, a running motor, and heat-generating electronic devices. Air conditioning to an appropriate temperature and humidity and management of on-board devices to an appropriate temperature are collectively referred to as "thermal management."

[0013] The temperature control system 1A and the electrically-driven devices and electronic devices provided in the in-vehicle device are supplied with power stored in an in-vehicle battery device. The in-vehicle battery device is charged from an external power source when the vehicle is stopped.

[0014] The temperature adjustment system 1A includes a refrigerant circuit 10 configured to allow a refrigerant to circulate, a heat medium circuit 20 configured to allow a heat medium to circulate for transferring heat to and from the refrigerant, and a control unit (not shown) that sets the temperature adjustment system 1A to a predetermined operating mode and controls the operating state of the temperature adjustment system 1A depending on the operating mode. The temperature adjustment system 1A also 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 vehicle interior 8.

[0015] The temperature adjustment system 1A has a plurality of operation modes that can be selected by the occupant or the control unit. In this embodiment, the operation modes of the temperature adjustment system 1A are exemplified by a cooling mode (FIG. 1), a heat pump mode (FIG. 2), and a heater mode (FIG. 3).

[0016] <Configuration of refrigerant circuit 10> The refrigerant circuit 10 includes a compressor 11 for compressing the refrigerant, a condenser (high-pressure heat exchanger) 12, an expansion valve (pressure reducing section) 13, and an evaporator (low-pressure heat exchanger) 14. In the refrigerant circuit 10, the refrigerant circulates according to a refrigeration cycle. As the refrigerant filled 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) refrigerants such as propane and isobutane can be used. In particular, it is preferable to use R1234yf as the refrigerant in this embodiment.

[0017] When the above-listed fluorocarbon or hydrocarbon refrigerants are used, a subcritical refrigeration cycle is formed in which the refrigerant pressure on the high pressure side does not exceed the critical pressure of the refrigerant. When carbon dioxide (CO2) is used 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 this case, the refrigerant dissipates heat through the high pressure side heat exchanger, similar to the condenser 12 of this embodiment, and the refrigerant absorbs heat through the low pressure side heat exchanger, similar to the evaporator 14 of this embodiment, so that a refrigerant that configures a transcritical refrigeration cycle, such as carbon dioxide refrigerant, can also be used in the refrigerant circuit 10.

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

[0019] The condenser 12 exchanges heat between the refrigerant gas discharged from the compressor 11 and the heat medium flowing through the heat medium circuit 20 .

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

[0021] The evaporator 14 exchanges heat between the refrigerant flowing out from the expansion valve 13 and the heat medium flowing through the heat medium circuit 20. The refrigerant 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] In the refrigerant circuit 10 in Fig. 1, the flow of the refrigerant on the low pressure side is indicated by a thin solid line, and the flow of the refrigerant on the high pressure side is indicated by a thin dashed dotted line. The same is true for Fig. 2 and the subsequent figures.

[0023] The compressor 11, the condenser 12, the expansion valve 13, the evaporator 14, and the refrigerant piping connecting these elements are installed outside the vehicle compartment 8, for example.

[0024] 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. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program, for example, and the CPU reads this program into the RAM or the like and executes information processing and arithmetic processing to realize various functions. The program may be installed in a ROM or other storage medium in advance, may be provided in a state stored in a computer-readable storage medium, or may be distributed via a wired or wireless communication means. The computer-readable storage medium may be a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

[0025] <Configuration of the heat medium circuit 20> The heat medium circuit 20 is configured to circulate a heat medium capable of transferring heat to and from the refrigerant through the condenser 12 and the evaporator 14. The heat medium is used to cool or heat at least one temperature control target. In this embodiment, the temperature control target is air that is supplied to the vehicle interior 8 for air conditioning.

[0026] The heat medium sealed in the heat medium circuit 20 is a liquid such as water or brine that is maintained in a liquid phase and circulates through the heat medium circuit 20. Examples of the brine include a mixture of water and propylene glycol, or a mixture of water and ethylene glycol.

[0027] The heat medium circuit 20 includes an outdoor heat exchanger 23 and an indoor unit (temperature adjustment device) 25.

[0028] The exterior heat exchanger 23 exchanges heat between the heat medium and the outside air outside the vehicle compartment 8. The exterior heat exchanger 23 is disposed, for example, near an air inlet of the vehicle. The outside air supplied to the exterior heat exchanger 23 by the running of the vehicle and the operation of the exterior heat exchanger fan 23a releases or absorbs heat based on the temperature difference between the outside air and the heat medium.

[0029] The indoor unit 25 includes an indoor fan 25a, a first indoor heat exchanger 25b, and a second indoor heat exchanger 25c. The indoor unit 25 provides conditioned air into the vehicle compartment 8 by exchanging heat between the air sent by the indoor fan 25a and a heat medium. The indoor fan 25a is driven by an electric motor based on a command from the control unit, and blows air in the vehicle compartment 8 (indoor air) or outside air, or a mixture of the inside air and the outside air, toward the first indoor heat exchanger 25b and the second indoor heat exchanger 25c.

[0030] The heat medium circuit 20 includes a first pump 21 and a second pump 22 that transport the heat medium. The start and stop and rotation speed of the first pump 21 and the second pump 22 are controlled by a control unit.

[0031] The first pump 21 is connected to a condenser outlet pipe (piping for the first pump) 31 connected to the heat medium outlet side of the condenser 12. The outlet side of the first pump 21 is connected to the second indoor heat exchanger 25c via the first pump outlet pipe 33 and the second indoor unit inlet pipe 34. The first pump outlet pipe 33 is provided with a first three-way valve 35. The first three-way valve 35 determines whether the heat medium discharged from the first pump 21 is directed to the second indoor heat exchanger 25c via the second indoor unit inlet pipe 34 or to one of the outdoor heat exchangers 23 via the first outdoor unit inlet pipe 37. The first three-way valve 35 is controlled by the control unit.

[0032] A second indoor unit outlet pipe 39 is provided on the heat medium outflow side of the second indoor heat exchanger 25c. The second indoor unit outlet pipe 39 is connected to a four-way valve 40. The four-way valve 40 is controlled by the control unit, and the connection direction is switched depending on the operation mode.

[0033] A condenser return pipe 42 is provided between the four-way valve 40 and the condenser 12. The heat medium is returned to the condenser 12 through the condenser return pipe 42.

[0034] The second pump 22 is connected to an evaporator outlet pipe (piping for the second pump) 44 that is connected to the heat medium outlet side of the evaporator 14. A bypass flow control valve (flow control valve) 46 and a connection valve 48 are provided in this order from the evaporator 14 side on the evaporator outlet pipe 44.

[0035] The bypass flow rate control valve 46 is connected to the outlet side of an evaporator bypass pipe (low-pressure heat medium side bypass pipe) 52 that branches off from an evaporator inlet pipe 50 on the inlet side of the evaporator 14 and is provided so as to bypass the evaporator 14. The bypass flow rate control valve 46 adjusts the flow rate ratio of the heat medium flowing to the evaporator 14 and the heat medium flowing to the evaporator bypass pipe 52 in response to a command from the control unit.

[0036] The connection valve 48 is connected to a condenser supply pipe (high pressure heat medium supply pipe) 54 which is connected to the condenser return pipe 42. The condenser supply pipe 54 guides the heat medium flowing out of the evaporator 14 to the condenser 12. In response to a command from the control unit, the connection valve 48 adjusts the flow rate ratio between the heat medium flowing in a direction toward the second pump 22 (first direction) and the heat medium flowing in a direction toward the condenser 12 (second direction).

[0037] A connection pipe 56 is provided between the evaporator outlet pipe 44 and the condenser outlet pipe 31. The connection pipe 56 is connected to the suction part 22a of the second pump 22 (downstream of the connection valve 48) and is also connected to the suction part 21a of the first pump 21.

[0038] A reserve tank 58 is provided on the connection pipe 56. When the heat medium sealed in the heat medium circuit 20 expands with an increase in temperature, the reserve tank 58 receives the heat medium in excess of the volume of the pipe of the heat medium circuit 20. When the volume of the heat medium decreases with a decrease in temperature, the heat medium is replenished from the reserve tank 58 to the pipe of the heat medium circuit 20, so that the inside of the pipe is kept filled with the heat medium. In other words, the reserve tank 58 can prevent the internal pressure of the pipe from becoming excessive or the inside of the pipe from becoming negative pressure. The inside of the reserve tank 58 is open to the atmosphere. The reserve tank 58 may be sealed to adjust the pressure to a desired constant pressure.

[0039] The connection pipe 56 is not provided with an on-off valve separating the reserve tank 58 from the suction portion 21a of the first pump 21 and the suction portion 22a of the second pump 22. That is, the reserve tank 58 and the suction portions 21a, 22a are maintained at the same pressure in either the cooling mode or the heat pump mode described below.

[0040] A second three-way valve 60 is provided on the outlet side of the second pump 22 via a second pump outlet piping 62. The second three-way valve 60 is connected to a first indoor unit inlet piping 64 leading to the first indoor heat exchanger 25b and a second outdoor unit inlet piping 66 leading to the outdoor heat exchanger 23. The second three-way valve 60 selects whether the heat medium flows to the first indoor heat exchanger 25b or the outdoor heat exchanger 23 in response to a command from the control unit.

[0041] A heat medium outlet side of the first indoor heat exchanger 25b is connected to a first indoor unit outlet piping 68. An outlet side of the first indoor unit outlet piping 68 is connected to the evaporator inlet piping 50.

[0042] An outdoor unit outlet pipe 70 is connected to the heat medium outlet side of the outdoor heat exchanger 23. The outlet side of the outdoor unit outlet pipe 70 is connected to the four-way valve 40.

[0043] Next, the control of the temperature adjustment system 1A having the above configuration will be described. <Cooling mode: Figure 1> In the cooling mode, cool air is supplied to the passenger compartment 8 using the indoor unit 25.

[0044] The refrigerant circuit 10 is started by a command from the control unit. As a result, the refrigerant is compressed by the compressor 11, and the high-temperature, high-pressure refrigerant is supplied to the condenser 12. In the condenser 12, the refrigerant exchanges heat with a heat medium to release condensation heat, and the refrigerant is condensed and liquefied. The liquefied high-pressure refrigerant is reduced in pressure by the expansion valve 13 and then supplied to the evaporator 14. In the evaporator 14, the refrigerant exchanges heat with the heat medium to obtain latent heat of evaporation and evaporates, becoming a low-pressure gas refrigerant. The low-pressure gas refrigerant that leaves the evaporator 14 is guided to the compressor 11 and repeats the above-mentioned refrigeration cycle.

[0045] In Fig. 1, the flow of the heat transfer medium is indicated by a thick line when it is flowing, and by a thin dashed line when it is not flowing. In addition, a low-temperature heat transfer medium is indicated by a thick solid line, and a high-temperature heat transfer medium is indicated by a thick dashed line. This notation is the same for Fig. 2 and subsequent figures.

[0046] The heat medium heated by the refrigerant in the condenser 12 passes through the condenser outlet pipe 31 by the action of the first pump 21 and is branched by the first three-way valve 35 to the first outdoor unit inlet pipe 37. Then, the heat medium exchanges heat with the outside air guided from the outdoor heat exchanger fan 23a in the outdoor heat exchanger 23 and dissipates heat. The heat medium that has been cooled by dissipating heat passes through the outdoor unit outlet pipe 70, has its flow path switched by the four-way valve 40 to the condenser return pipe 42, and is guided to the condenser 12. In this way, in the cooling mode, the heat medium is circulated between the condenser 12 and the outdoor heat exchanger 23 by the first pump 21.

[0047] The heat medium cooled by the refrigerant in the evaporator 14 is guided to the first indoor heat exchanger 25b through the evaporator outlet piping 44 and the first indoor unit inlet piping 64 by the action of the second pump 22. In the first indoor heat exchanger 25b, the air in the passenger compartment 8 (or outside air) guided from the indoor fan 25a is cooled by providing cold energy to the air by the heat medium cooled in the evaporator 14. As a result, the passenger compartment 8 is cooled to a desired temperature.

[0048] The heat medium leaving the first indoor heat exchanger 25b passes through the first indoor unit outlet piping 68 and flows to the evaporator 14 via the evaporator inlet piping 50. In this way, in the cooling mode, the heat medium is circulated between the evaporator 14 and the first indoor heat exchanger 25b by the second pump 22.

[0049] The suction portion 21a of the first pump 21 and the suction portion 22a of the second pump 22 are both connected to a reserve tank 58 via a connection pipe 56. This allows the pressure at each of the suction portions 21a, 22a to be maintained at atmospheric pressure.

[0050] <Heat pump mode: Figure 2> In the heat pump mode, heat is pumped up from the outside air as a heat source to heat the interior of the vehicle compartment 8.

[0051] The operation of the refrigerant circuit 10 is the same as in the cooling mode, and therefore a description thereof will be omitted.

[0052] The heat medium heated by the refrigerant in the condenser 12 passes through the condenser outlet pipe 31 by the action of the first pump 21 and is branched by the first three-way valve 35 to the second indoor unit inlet pipe 34. Then, in the second indoor heat exchanger 25c, the heat medium provides heat to the air in the vehicle compartment 8 (or outside air) guided from the indoor fan 25a, thereby heating the vehicle. The heat medium cooled by providing heat passes through the second indoor unit outlet pipe 39, has its flow path switched by the four-way valve 40 to the condenser return pipe 42, and is guided to the condenser 12. In this way, in the heat pump mode, the heat medium is circulated between the condenser 12 and the second indoor heat exchanger 25c by the first pump 21.

[0053] The heat medium cooled by the refrigerant in the evaporator 14 passes through the evaporator outlet pipe 44 by the action of the second pump 22, has its flow path switched to the second outdoor unit inlet pipe 66 by the second three-way valve 60, and is guided to the outdoor heat exchanger 23. In the outdoor heat exchanger 23, the heat medium absorbs heat from the outside air guided by the outdoor heat exchanger fan 23a, and the temperature increases.

[0054] The heat medium heated in the outdoor heat exchanger 23 passes through the outdoor unit outlet pipe 70, has its flow path switched to the evaporator inlet pipe 50 by the four-way valve 40, and is then guided to the evaporator 14. In the evaporator 14, heat absorbed from the outside air, which is a heat source, is given to the refrigerant via the heat medium. This causes the refrigerant circuit 10 to operate as a heat pump. In this way, in the heat pump mode, the heat medium is circulated between the evaporator 14 and the outdoor heat exchanger 23 by the second pump 22.

[0055] The suction portion 21a of the first pump 21 and the suction portion 22a of the second pump 22 are both connected to a reserve tank 58 via a connection pipe 56. This allows the pressure at each of the suction portions 21a, 22a to be maintained at atmospheric pressure.

[0056] <Heater mode: Figure 3> The heater mode is suitable for heating when the heat medium cannot absorb heat from the outside air because the outside air temperature is low. In the heater mode, the heat medium transports an amount of heat corresponding to the power of the compressor 11 as a heat source to the passenger compartment 8 while avoiding heat radiation from the heat medium to the outside air. This ensures heating capacity even when the outside air temperature is significantly below 0°C.

[0057] The operation of the refrigerant circuit 10 is the same as in the cooling mode, and therefore a description thereof will be omitted.

[0058] The heat medium heated by the refrigerant in the condenser 12 passes through the condenser outlet pipe 31 by the action of the first pump 21, and is branched by the first three-way valve 35 to the second indoor unit inlet pipe 34. Then, in the second indoor heat exchanger 25c, the heat medium provides heat to the air in the passenger compartment 8 (or outside air) guided from the indoor fan 25a, thereby heating the vehicle. The heat medium cooled by providing heat passes through the second indoor unit outlet pipe 39, and the flow path is switched by the four-way valve 40 to the evaporator inlet pipe 50, and the heat medium is guided to the evaporator 14.

[0059] A portion of the heat medium flowing through the evaporator inlet pipe 50 at the four-way valve 40 passes through the evaporator bypass pipe 52, bypasses the evaporator 14, and flows into the evaporator outlet pipe 44. The flow rate of the heat medium flowing into the evaporator bypass pipe 52 is controlled by the bypass flow rate control valve 46 under the command of the control unit. The amount of heat absorbed by the evaporator 14 is controlled by the flow rate ratio adjusted by the bypass flow rate control valve 46.

[0060] A portion of the heat medium leaving the bypass flow control valve 46 and flowing through the evaporator outlet pipe 44 is redirected by the connection valve 48 to the condenser supply pipe 54 and guided to the condenser 12. The heat medium flowing to the condenser 12 removes heat of condensation from the refrigerant flowing through the condenser 12, liquefying the refrigerant.

[0061] The remaining heat medium flowing through the evaporator outlet pipe 44 is guided to the first pump 21 through the connection pipe 56 by the connection valve 48. The second pump 22 is stopped by a command from the control unit, and the second three-way valve 60 is closed, so that no heat medium flows to the second pump 22. In addition, the stopped state of the second pump 22 is indicated by a black triangle in FIG. 3.

[0062] In this manner, in the heater mode, the heat medium circulates among the second indoor heat exchanger 25c, the condenser 12, and the evaporator 14 by the operation of only the first pump 21.

[0063] The suction portion 21a of the first pump 21 is connected to a reserve tank 58 via a connecting pipe 56. This allows the pressure at each suction portion 21a to be maintained at atmospheric pressure.

[0064] The effects of the present embodiment described above are as follows. By connecting the suction section 21a of the first pump 21 to one side of the reserve tank 58 and connecting the suction section 22a of the second pump 22 to the other side of the reserve tank 58, the suction pressures of the first pump 21 and the second pump 22 can be adjusted by the reserve tank 58. In this embodiment, since the reserve tank 58 is connected to the atmosphere, the suction pressures of the first pump 21 and the second pump 22 are prevented from becoming negative, and thus it is possible to prevent a negative pressure region from being formed in the heat medium circuit 20 as much as possible.

[0065] A connection valve 48 is provided on the evaporator outlet pipe 44 connecting the evaporator 14 and the second pump 22, making it possible to adjust the flow between a first direction in which the heat medium is supplied toward the second pump 22 and a second direction in which the heat medium is supplied to the condenser supply pipe 54. As a result, as shown in FIG. 3, it is possible to stop the operation of the second pump 22 by supplying the heat medium to the condenser supply pipe 54 via the connection valve 48. Therefore, it is not necessary to provide an opening / closing valve for making the suction pressures of the first pump 21 and the second pump 22, whose respective suction parts 21a and 22a are connected to the reserve tank 58, different from each other. Therefore, it is possible to switch the flow path of the heat medium with a simple configuration.

[0066] A connecting pipe 56 is provided between the suction portion 21a of the first pump 21 and the suction portion 22a of the second pump 22, and a reserve tank 58 is provided on this connecting pipe 56. Through this connecting pipe 56, the heat medium flowing out from the evaporator 14 during the heater mode can be guided to the first pump 21. This makes it possible to realize the heater mode with a simple configuration.

[0067] In the heater mode (FIG. 3), the heat medium is circulated only by the first pump 21, and the second pump 22 is stopped. This eliminates the need to operate the first pump 21 and the second pump 22 simultaneously to form a heat medium circuit in series.

[0068] Since the bypass flow rate control valve 46 is provided to adjust the flow rate ratio of the heat medium flowing to the evaporator 14 and the heat medium flowing to the evaporator bypass pipe 52, it is possible to adjust the amount of heat absorbed by the refrigerant circuit in the evaporator 14. This makes it possible to appropriately control the heater mode.

[0069] <<Variation 1>> This embodiment can be modified as shown in FIG. In the above-described embodiment, the bypass flow rate adjustment valve 46 and the connection valve 48 are configured separately, but they may be integrated to form the flow rate adjustment connection valve 72. When integrated, for example, the main body forming the flow path is integrated using resin. In addition, there are multiple valve cores (two three-way valves). Preferably, they are operated by one actuator.

[0070] The flow rate control connection valve 72 adjusts the flow rate of the evaporator bypass piping 52 in the same manner as the bypass flow rate control valve 46 shown in Figure 3 etc., and adjusts the flow rate of the condenser supply piping 54 in the same manner as the connection valve 48 shown in Figure 3 etc. By integrating the functions of the bypass flow rate control valve 46 and the connection valve 48, the number of constituent devices can be reduced.

[0071] [Second embodiment] Next, a second embodiment of the present disclosure will be described with reference to Fig. 5. This embodiment is similar to the first embodiment except for the position of the first pump 21. Therefore, only the differences will be described below, and the same reference numerals will be used to denote the same configurations, and the description thereof will be omitted.

[0072] 5, in the temperature adjustment system 1B of the present embodiment, a reserve tank 58 is installed in the condenser supply pipe 54. The downstream end of the condenser supply pipe 54 is connected to the condenser return pipe 42 at a connection part 74. The first pump 21 is provided between the inlet side of the condenser 12 and the connection part 74.

[0073] In the present embodiment as well, in the heater mode, the heat medium is circulated among the second indoor heat exchanger 25c, the condenser 12, and the evaporator by the operation of only the first pump 21.

[0074] According to this embodiment, the connection pipe 56 (FIG. 1, etc.) of the first embodiment can be omitted, and the configuration can be further simplified.

[0075] <<Variation 2>> This embodiment can be modified as shown in FIG. In the above-described embodiment, the bypass flow rate adjustment valve 46 and the connection valve 48 are configured separately, but they may be integrated to form the flow rate adjustment connection valve 72. When integrated, for example, the main body forming the flow path is integrated using resin. In addition, there are multiple valve cores (two three-way valves). Preferably, they are operated by one actuator.

[0076] [Third embodiment] Next, a third embodiment of the present disclosure will be described with reference to Fig. 7. This embodiment differs in that a refrigerant is supplied to the first indoor heat exchanger 25b. The heat medium circuit 20 is basically the same as that of the first embodiment. Therefore, only the differences will be described below, and the same reference numerals will be used to denote the other similar configurations, and the description thereof will be omitted.

[0077] 7, in the temperature adjustment system 1C of the present embodiment, a refrigerant is supplied to the first indoor heat exchanger 25b. That is, a high-pressure refrigerant pipe 76 branched off from the refrigerant outlet side of the condenser 12 is connected to the inlet side of the first indoor heat exchanger 25b, and a low-pressure refrigerant pipe 78 connected to the outlet side of the first indoor heat exchanger 25b is connected to the suction side of the compressor 11.

[0078] A second expansion valve 77 is provided in the high-pressure refrigerant pipe 76. In the cooling mode, the second expansion valve 77 is operated by a command from the control unit, so that the first indoor heat exchanger 25b can be used as an evaporator.

[0079] In this embodiment, the connection valve 48' is a four-way valve, unlike the connection valve 48 in the first embodiment, but is similar to the first embodiment in that it has a function of adjusting the flow rate of the condenser supply pipe 54. Furthermore, the connection valve 48' is capable of controlling the flow of the heat medium in the directions of the connection pipe 56 and the second pump 22.

[0080] In the heat pump mode and the heater mode, the second expansion valve 77 is stopped, and no refrigerant flows into the first indoor heat exchanger 25b.

[0081] In the present embodiment as well, in the heater mode, the heat medium circulates among the second indoor heat exchanger 25c, the condenser 12, and the evaporator 14 by the operation of only the first pump 21.

[0082] The temperature adjustment system and the control method thereof described in each of the above-described embodiments can be understood, for example, as follows.

[0083] A temperature adjustment system (1A, 1B, 1C) according to a first aspect of the present disclosure includes a refrigerant circuit (10) in which a refrigerant circulates through a compressor (11), a high-pressure side heat exchanger (12), a pressure reducing section (13) and a low-pressure side heat exchanger (14), and a heat medium circuit (20) in 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 an outdoor heat exchanger (23) for exchanging heat between outside air and the heat medium, a temperature adjustment device (25) for heating or cooling a temperature adjustment target using the heat medium, a reserve tank (58) for storing the heat medium, and a suction section (21a) on one side of the reserve tank. the low-pressure side heat exchanger and the second pump, and a suction portion (22a) connected to the other side of the reserve tank, and a connection valve (48, 48') provided in a second pump piping (44) connecting the heat medium outlet side of the low-pressure side heat exchanger and the second pump, and a heat medium high-pressure side supply piping (54) connecting the connection valve and the heat medium inlet side of the high-pressure side heat exchanger, the connection valve being capable of adjusting the flow between a first direction in which the heat medium is supplied toward the second pump and a second direction in which the heat medium is supplied to the heat medium high-pressure side supply piping.

[0084] By connecting the suction part of the first pump to one side of the reserve tank and the suction part of the second pump to the other side of the reserve tank, the suction pressures of the first pump and the second pump can be adjusted by the reserve tank. For example, if the reserve tank is connected to the atmosphere, the suction pressures of the first pump and the second pump can be prevented from becoming negative, and the formation of a negative pressure region in the heat medium circuit can be prevented as much as possible. A connection valve is provided in the second pump pipe connecting the low pressure side heat exchanger and the second pump, making it possible to adjust the flow between a first direction in which the heat medium is supplied toward the second pump and a second direction in which the heat medium is supplied to the high pressure side heat medium supply pipe. This makes it possible to stop the operation of the second pump by supplying the heat medium to the high pressure side heat exchanger via the connection valve. Therefore, it is not necessary to provide an opening / closing valve for making the pressures of the suction parts of the first pump and the second pump, each of which has a suction part connected to the reserve tank, different. This makes it possible to switch the flow path of the heat medium with a simple configuration.

[0085] A temperature adjustment system according to a second aspect of the present disclosure, in the above-mentioned first aspect, includes a first pump piping (31) connecting the high-pressure side heat exchanger and the first pump, and a connection piping (56) connecting the suction portion of the first pump in the first pump piping and the suction portion of the second pump in the second pump piping, and the reserve tank is provided in the connection piping.

[0086] A connection pipe is provided that connects the suction portion of the first pump in the first pump pipe and the second pump pipe, and a reserve tank is provided in this connection pipe. By supplying the heat medium to the high-pressure side heat exchanger through the connecting valve, it is possible to stop the operation of the second pump. Therefore, there is no need to provide an on-off valve for making the pressures of the suction parts of the first pump and the second pump different in the connecting pipe provided with the reserve tank.

[0087] A temperature adjustment system according to a third aspect of the present disclosure is the same as the first aspect, except that the reserve tank is provided in the heat medium high-pressure side supply piping, a downstream end of the heat medium high-pressure side supply piping is connected to a condenser return piping at a connection part, and the first pump is provided between a downstream end (74) of the heat medium high-pressure side supply piping and an inlet side of the high-pressure side heat exchanger.

[0088] The suction part of the first pump is connected to a reserve tank provided in the heat medium high-pressure supply pipe via the downstream end of the heat medium high-pressure supply pipe, and the suction part of the second pump is connected to the reserve tank via a connection valve and the heat medium high-pressure supply pipe. By supplying the heat medium to the high-pressure side heat exchanger through the connection valve, it is possible to stop the operation of the second pump. Therefore, it is not necessary to provide an on-off valve for making the pressures of the suction parts of the first pump and the second pump different in the heat medium high-pressure side supply pipe provided with the reserve tank.

[0089] In a temperature control system according to a fourth aspect of the present disclosure, in any one of the first to third aspects, in a heater mode in which heat absorption in the outdoor heat exchanger is stopped and heat is supplied to the temperature control device, the control unit operates the refrigerant circuit, stops the second pump, and starts the first pump to control the heat medium to flow sequentially through the high-pressure side heat exchanger, the temperature control device, and the low-pressure side heat exchanger, and then guides it to the high-pressure side heat exchanger.

[0090] When the outdoor temperature is below 0°C, if the heat pump is operated using outdoor air as a heat source, there is a risk that the heat absorption from the outdoor air will be insufficient, resulting in insufficient heating, and there is also a risk of frost forming on the outdoor heat exchanger. Therefore, the system is switched to heater mode, and the heat absorption by the outdoor heat exchanger is stopped. In the heater mode, the refrigerant circuit is operated, and the heat medium is heated by passing it through the high-pressure heat exchanger and supplied to the temperature control device. After being heated by the temperature control device, the heat medium is absorbed by the refrigerant circuit in the low-pressure heat exchanger. In this way, the heat pump operation of the refrigerant circuit is performed using the heat medium that has been heated by the temperature control device as a heat source. The heat transfer medium is circulated by the first pump, and the second pump is stopped, which eliminates the need to operate the first and second pumps simultaneously to form a heat transfer medium circuit in series.

[0091] The temperature adjustment system according to a fifth aspect of the present disclosure is the temperature adjustment system of the fourth aspect, further comprising: a heat medium low-pressure side bypass piping (52) branching off from the heat medium flow upstream side of the low-pressure side heat exchanger and bypassing the low-pressure side heat exchanger to merge with the second pump piping; and a flow control valve (46) adjusting a flow rate ratio of the heat medium flowing to the low-pressure side heat exchanger and the heat medium flowing to the heat medium low-pressure side bypass piping.

[0092] By providing a flow rate control valve that adjusts the flow rate ratio of the heat medium flowing to the low-pressure heat exchanger and the heat medium flowing to the low-pressure heat medium bypass pipe, the amount of heat absorbed by the refrigerant circuit in the low-pressure heat exchanger can be adjusted, thereby making it possible to appropriately control the heater mode.

[0093] A sixth aspect of the present disclosure relates to a temperature regulation system according to the fifth aspect, wherein the connection valve and the flow rate adjustment valve are integrated together.

[0094] By integrating the connection valve and the flow rate adjustment valve, the number of components can be reduced. When they are integrated, for example, the main body that forms the flow path is integrated using resin. And, there are multiple valve cores (two three-way valves). It is preferable to operate them with one actuator.

[0095] A temperature control system according to a seventh aspect of the present disclosure is any one of the first to sixth aspects, in which in a cooling mode in which cold heat is supplied by the temperature control device, the control unit operates the refrigerant circuit, starts the first pump to circulate the heat medium between the high-pressure side heat exchanger and the outdoor heat exchanger, and starts the second pump to circulate the heat medium between the low-pressure side heat exchanger and the temperature control device.

[0096] In the cooling mode, the heat medium circulated by the first pump absorbs heat from the refrigerant in the high-pressure heat exchanger (condenser) and releases it in the outdoor heat exchanger. The heat medium circulated by the second pump is cooled in the low-pressure heat exchanger (evaporator) and supplies cold heat to the temperature control equipment.

[0097] In a temperature control system according to an eighth aspect of the present disclosure, in any one of the first to seventh aspects described above, in a heat pump mode in which heat is absorbed in the outdoor heat exchanger and warm heat is supplied to the temperature control device, the control unit operates the refrigerant circuit, starts the first pump to circulate the heat medium between the high-pressure side heat exchanger and the temperature control device, and starts the second pump to circulate the heat medium between the low-pressure side heat exchanger and the outdoor heat exchanger.

[0098] In the heat pump mode, the heat medium circulated by the first pump is heated in the high pressure side heat exchanger (condenser) and supplies heat to the temperature control equipment. The heat medium circulated by the second pump absorbs heat from the outside air in the outdoor heat exchanger and supplies heat to the refrigerant circuit operating as a heat pump in the low pressure side heat exchanger (evaporator).

[0099] A control method for a temperature adjustment system according to a first aspect of the present disclosure includes a refrigerant circuit in which a refrigerant circulates through a compressor, a high-pressure side heat exchanger, a pressure reducing unit, and a low-pressure side heat exchanger, and a heat medium circuit in 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 including an outdoor heat exchanger that exchanges heat between outdoor air and the heat medium, a temperature adjustment device that uses the heat medium to heat or cool a temperature adjustment target, a reserve tank that stores the heat medium, and a suction unit that is connected to one side of the reserve tank and transports the heat medium. A control method for a temperature adjustment system including a first pump, a second pump having an inlet connected to the other side of the reserve tank and transporting a heat medium, a connection valve provided in a second pump piping connecting a heat medium outlet side of the low-pressure side heat exchanger and the second pump, and a high-pressure side heat medium supply piping connecting the connection valve and the heat medium inlet side of the high-pressure side heat exchanger, wherein the connection valve is used to adjust a flow of the heat medium in a first direction toward the second pump and a second direction to supply the heat medium to the high-pressure side heat medium supply piping. [Explanation of symbols]

[0100] 1A, 1B, 1C Temperature Control System 8 Cabin 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) 20 Heat carrier circuit 21 First Pump 21a Intake section 22 Second Pump 22a Intake section 23 Outdoor heat exchanger 23a Outdoor heat exchanger fan 25 Indoor unit (temperature control equipment) 25a Indoor fan 25b 1st indoor heat exchanger 25c 2nd indoor heat exchanger 31 Condenser outlet piping (piping for first pump) 33 First pump outlet piping 34 Second indoor unit inlet piping 35 First three-way valve 37 1st outdoor unit inlet piping 39 2nd indoor unit outlet piping 40 Four-way valve 42 Condenser return pipe 44 Evaporator outlet piping (piping for second pump) 46 Bypass flow control valve (flow control valve) 48,48' Connection valve 50 Evaporator inlet piping 52 Evaporator bypass piping (low pressure side bypass piping for heat transfer medium) 54 Condenser supply piping (high pressure heat medium supply piping) 56 Connection piping 58 Reserve Tank 60 2nd three-way valve 62 Second pump outlet piping 64 First indoor unit inlet piping 66 2nd outdoor unit inlet piping 68 1st indoor unit outlet piping 70 Outdoor unit outlet piping 72 Flow control connection valve 74 Connection 76 High pressure refrigerant piping 77 Second expansion valve 78 Low pressure refrigerant piping

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 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; Equipped with The heat medium circuit includes: an outdoor heat exchanger that exchanges heat between outdoor air and a heat medium; A temperature control device that uses a heat medium to heat or cool a temperature control target; a reserve tank for storing the heat medium; a first pump having a suction portion connected to one side of the reserve tank and configured to transport a heat medium; a second pump having a suction portion connected to the other side of the reserve tank and configured to transport the heat medium; a connecting valve provided in a second pump pipe connecting a heat medium outlet side of the low-pressure side heat exchanger and the second pump; a heat medium high-pressure side supply pipe connecting the connection valve and a heat medium inlet side of the high-pressure side heat exchanger; Equipped with The connection valve is capable of adjusting a flow of the heat medium between a first direction in which the heat medium is supplied toward the second pump and a second direction in which the heat medium is supplied to the heat medium high pressure side supply pipe.

2. a first pump pipe connecting the high-pressure side heat exchanger and the first pump; a connection pipe that connects the suction portion of the first pump in the first pump pipe and the suction portion of the second pump in the second pump pipe; Equipped with The temperature adjustment system according to claim 1 , wherein the reserve tank is provided in the connection pipe.

3. The reserve tank is provided in the heat medium high pressure side supply pipe, 2. The temperature control system according to claim 1, wherein a downstream end of the heat medium high-pressure side supply piping is connected to a condenser return piping at a connection portion, and the first pump is provided between the downstream end of the heat medium high-pressure side supply piping and an inlet side of the high-pressure side heat exchanger.

4. In a heater mode in which heat absorption in the outdoor heat exchanger is stopped and heat is supplied to the temperature control device, The control unit operates the refrigerant circuit, The temperature control system according to claim 1, wherein the second pump is stopped and the first pump is started, and the heat medium is sequentially passed through the high-pressure side heat exchanger, the temperature control device, and the low-pressure side heat exchanger, and then is directed to the high-pressure side heat exchanger.

5. a low-pressure side bypass pipe for a heat medium that branches off from an upstream side of the low-pressure side heat exchanger and merges with the second pump pipe while bypassing the low-pressure side heat exchanger; a flow rate control valve for controlling a flow rate ratio of the heat medium flowing to the low-pressure side heat exchanger and the heat medium flowing to the low-pressure side bypass piping; The temperature control system according to claim 4 .

6. The temperature adjustment system according to claim 5 , wherein the connection valve and the flow rate adjustment valve are integrated together.

7. In a cooling mode in which cold heat is supplied by the temperature control device, The control unit operates the refrigerant circuit, The temperature control system according to claim 1, wherein the first pump is started to circulate the heat medium between the high-pressure side heat exchanger and the outdoor heat exchanger, and the second pump is started to circulate the heat medium between the low-pressure side heat exchanger and the temperature control equipment.

8. In a heat pump mode in which heat is absorbed by the outdoor heat exchanger and heat is supplied to the temperature control device, The control unit operates the refrigerant circuit, The temperature control system according to claim 1, wherein the first pump is started to circulate the heat medium between the high-pressure side heat exchanger and the temperature control equipment, and the second pump is started to circulate the heat medium between the low-pressure side heat exchanger and the outdoor heat exchanger.

9. 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 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; Equipped with The heat medium circuit includes: an outdoor heat exchanger that exchanges heat between outdoor air and a heat medium; A temperature control device that uses a heat medium to heat or cool a temperature control target; a reserve tank for storing the heat medium; a first pump having a suction portion connected to one side of the reserve tank and configured to transport a heat medium; a second pump having a suction portion connected to the other side of the reserve tank and configured to transport the heat medium; a connecting valve provided in a second pump pipe connecting a heat medium outlet side of the low-pressure side heat exchanger and the second pump; a heat medium high-pressure side supply pipe connecting the connection valve and a heat medium inlet side of the high-pressure side heat exchanger; A control method for a temperature adjustment system comprising: A control method for a temperature adjustment system, comprising: adjusting, using the connection valve, a flow of the heat medium in a first direction in which the heat medium is supplied toward the second pump; and a flow of the heat medium in a second direction in which the heat medium is supplied to the high-pressure heat medium supply pipe.

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