Temperature control system and method for controlling the temperature control system

Abstract

This invention provides a temperature control system and a control method for such a system that can quickly initiate a specific mode through the configuration and control of the refrigerant circuit. [Solution] The system comprises a refrigerant circuit 10 through which refrigerant RF circulates, a heat transfer medium HM that exchanges heat with the refrigerant RF circulates in a heat transfer medium HM circuit 20, and a control unit 40. The heat transfer medium circuit 20 has an indoor air conditioning unit 23 that heats a temperature-controlled object using the heat transfer medium HM. In heater mode, the control unit 40 mixes the heat transfer medium HM discharged from the condenser 12 with the heat transfer medium HM discharged from the evaporator 14, flows the mixed heat transfer medium HM into the condenser 12 and the evaporator 14, and also flows the heat transfer medium HM discharged from the condenser 12 into the indoor air conditioning unit 23. The control unit 40 determines whether the refrigerant RF discharged from the condenser 12 is in a gas-liquid two-phase or liquid phase and controls the expansion valve 13.

Description

Technical Field

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[0001] The present disclosure relates to a temperature control system 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 (for example, Patent Document 1). The vehicle thermal management system disclosed in Patent Document 1 can execute an operation mode (third operation mode) in which a cooling water circuit is configured by a pump, a cooling water cooler, a cooling water heater, and a device to be heated.

[0003] In the third operation mode of Patent Document 1, when supplying a heat medium to the device to be heated, the heat medium discharged from the pump is branched into three systems, namely, a low-pressure side heat exchanger, a high-pressure side heat exchanger, and the device to be heated, by a first switching valve and supplied to each of them, and the three systems are merged into one by a second switching valve and then led back to the pump again. And by executing this operation mode, it is said that the device to be heated can be heated at an early stage at a low outside air temperature.

Prior Art Documents

Patent Documents

[0007] To solve the above problems, the temperature control system and control method for the temperature control system of this disclosure employ the following means.

[0008] A temperature control system according to one aspect of the present disclosure comprises a compressor, a high-pressure side heat exchanger, a pressure reducing unit, and a low-pressure side heat exchanger, a refrigerant circuit through which a refrigerant circulates, a heat transfer medium circuit through which a heat transfer 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, wherein the heat transfer medium circuit has a temperature control device that heats a temperature control target using the heat transfer medium, and the control unit controls the pressure reducing unit by determining whether the refrigerant circulating from the high-pressure side heat exchanger is in a gas-liquid two-phase or liquid phase.

[0009] A control method for a temperature control system according to one aspect of the present disclosure comprises a refrigerant circuit through which a refrigerant circulates, having a compressor, a high-pressure side heat exchanger, a pressure reducing unit, and a low-pressure side heat exchanger, and a heat transfer medium circuit through which a heat transfer medium that exchanges heat with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger circulates, wherein the heat transfer medium circuit has a temperature control device that heats a temperature control target using the heat transfer medium, and in a heater mode in which the heat transfer medium discharged from the high-pressure side heat exchanger is mixed with the heat transfer medium discharged from the low-pressure side heat exchanger, the mixed heat transfer medium is flowed into the high-pressure side heat exchanger and the low-pressure side heat exchanger, and the heat transfer medium discharged from the high-pressure side heat exchanger is flowed into the temperature control device, the method adjusts the pressure reducing unit by determining whether the refrigerant discharged from the high-pressure side heat exchanger is in a gas-liquid two-phase or liquid phase. [Effects of the Invention]

[0010] According to this disclosure, a specific mode can be activated early by configuring and controlling the refrigerant circuit. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing a temperature control system (when heater mode is executed) according to the first embodiment of this disclosure. [Figure 2] This is a Mollier diagram (ph diagram) of the refrigerant circuit when heater mode is running. [Figure 3] This is a schematic diagram showing a temperature control system (when heater mode is executed) according to a modified example of the first embodiment of the present disclosure. [Figure 4] This is a schematic diagram showing a temperature control system (when heater mode is executed) according to the second embodiment of this disclosure. [Figure 5] This is a schematic diagram showing a temperature control system (when heater mode is executed) according to Modification 1 of the second embodiment of the present disclosure. [Figure 6] This is a schematic diagram showing a temperature control system (when heater mode is executed) according to a modified example 2 of the second embodiment of the present disclosure. [Modes for carrying out the invention]

[0012] Hereinafter, the temperature control system and control method for the temperature control system according to the first and second embodiments of this disclosure will be described with reference to the drawings. In the following explanation, pipe names may be distinguished, but this does not necessarily mean that each pipe is a separate pipe. Conversely, separate pipes may be combined to form a pipe system with the same name.

[0013] [First Embodiment] The temperature control system 1 is a system installed in a vehicle not shown in the figure. Examples of vehicles include electric vehicles that do not have an engine and obtain driving force for vehicle travel from an electric motor, and so-called hybrid vehicles that obtain driving force for vehicle travel from an engine and / or an electric motor.

[0014] The temperature control system 1 is responsible for air conditioning such as heating, cooling, dehumidifying, and ventilating the passenger compartment where passengers board, as well as heat management and / or waste heat recovery of in-vehicle devices such as a battery device (power supply device), a driving motor, and heat-generating electronic devices mounted on the vehicle. "Heat management" is a general term for air conditioning to an appropriate temperature and humidity and managing in-vehicle devices at an appropriate temperature.

[0015] Electric power stored in the battery device is supplied to the electric devices and electronic devices provided in the temperature control system 1 and the in-vehicle devices. The battery device is charged from an external power source, for example, when the vehicle is stopped.

[0016] The temperature control system 1 includes a refrigerant circuit 10 configured such that a refrigerant RF circulates, a heat medium circuit 20 configured such that a heat medium HM that exchanges heat with the refrigerant RF circulates, and a control unit 40 that controls electric devices and electronic devices provided in each circuit. The temperature control system 1 includes sensors (not shown) for obtaining information (for example, temperature and pressure) necessary for control, such as a sensor for detecting the outside air temperature, a sensor for detecting the temperature of the conditioned air blown into the passenger compartment, a sensor for detecting the temperature of the passenger compartment, a sensor for detecting the temperature of the refrigerant RF, a sensor for detecting the temperature of the heat medium HM, a sensor for detecting the pressure of the refrigerant RF, and the like.

[0017] The temperature control system 1 can execute an operation mode selected by a passenger or by the control unit 40. Examples of the operation modes of the temperature control system 1 according to the present embodiment include a heater mode and a heat pump mode (not shown).

[0018] <Configuration of Refrigerant Circuit> As shown in FIG. 1, the refrigerant circuit 10 includes a compressor 11 that compresses the refrigerant RF, a condenser (high-pressure side heat exchanger) 12 that condenses the refrigerant RF, an expansion valve (pressure reducing section) 13 that reduces the pressure of the refrigerant RF, an evaporator (low-pressure side heat exchanger) 14 that evaporates the refrigerant RF, and a plurality of pipes that connect the respective devices. The refrigerant circuit 10 is filled with the refrigerant RF. The enclosed refrigerant RF circulates in the refrigerant circuit 10 according to a known refrigeration cycle.

[0019] A single refrigerant or a mixed refrigerant is adopted for the refrigerant RF. For example, for the refrigerant RF, HFC (Hydro Fluoro Carbon) refrigerants such as R410A and R32, HFO (Hydro Fluoro Olefin) refrigerants such as R1234ze and R1234yf, and hydrocarbon (HC) - based refrigerants such as propane and isobutane can be adopted. In particular, it is preferable to use propane as the refrigerant RF of the present embodiment.

[0020] When using the exemplified fluorine - based or hydrocarbon - based refrigerant RF, the refrigerant circuit 10 constitutes a sub - critical refrigeration cycle in which the refrigerant pressure on the high - pressure side does not exceed the critical pressure of the refrigerant RF. When using carbon dioxide (CO2) as the refrigerant RF, the refrigerant circuit 10 constitutes a transcritical refrigeration cycle in which the refrigerant pressure on the high - pressure side exceeds the critical pressure of the refrigerant RF. Even in that case, the refrigerant RF dissipates heat by the high - pressure side heat exchanger similar to the condenser 12 of the present embodiment, and the refrigerant RF absorbs heat by the low - pressure side heat exchanger similar to the evaporator 14 of the present embodiment.

[0021] The compressor 11 is a device that compresses the refrigerant RF led from the evaporator 14. The compressor 11 is, for example, an electric compressor provided with an electric motor (not shown). The rotation speed of the compressor 11 is controlled by the control unit 40. Examples of the compressor 11 include a scroll compressor and a rotary compressor.

[0022] One end of the compressor refrigerant piping L11 is connected to the refrigerant outlet (discharge port) of the compressor 11. The other end of the compressor refrigerant piping L11 is connected to the refrigerant inlet of the condenser 12. In other words, the compressor refrigerant piping L11 is the piping that connects the discharge port of the compressor 11 to the refrigerant inlet of the condenser 12.

[0023] The condenser 12 is a heat exchanger that exchanges heat between the refrigerant RF, which is introduced from the compressor 11 via the compressor refrigerant piping L11, and the heat transfer medium HM flowing through the heat transfer medium circuit 20.

[0024] One end of the condenser refrigerant piping L12 is connected to the refrigerant outlet of the condenser 12. The other end of the condenser refrigerant piping L12 is connected to the refrigerant inlet of the expansion valve 13. In other words, the condenser refrigerant piping L12 is the piping that connects the refrigerant outlet of the condenser 12 to the refrigerant inlet of the expansion valve 13.

[0025] The expansion valve 13 is a device that reduces the pressure of the refrigerant RF led from the condenser 12 via the condenser refrigerant piping L12 and also adjusts the flow rate of the refrigerant RF. An example of an expansion valve 13 is an electronic expansion valve whose opening degree is controlled based on a command from the control unit 40.

[0026] By adjusting the opening degree of the expansion valve 13, the state of the refrigerant RF flowing out of the condenser 12 can be changed. For example, by adjusting the opening degree of the expansion valve 13, the refrigerant RF flowing out of the condenser 12 can be in liquid phase or gas-liquid two-phase. Furthermore, when the refrigerant RF is in gas-liquid two-phase, the moisture (dryness) of the refrigerant RF can also be changed by adjusting the opening degree of the expansion valve 13.

[0027] One end of the expansion valve refrigerant piping L13 is connected to the refrigerant outlet of the expansion valve 13. The other end of the expansion valve refrigerant piping L13 is connected to the refrigerant inlet of the evaporator 14. In other words, the expansion valve refrigerant piping L13 is the piping that connects the refrigerant outlet of the expansion valve 13 to the refrigerant inlet of the evaporator 14.

[0028] The evaporator 14 is a device that exchanges heat between the refrigerant RF, which is introduced from the expansion valve 13 via the expansion valve refrigerant piping L13, and the heat transfer medium HM flowing through the heat transfer medium circuit 20.

[0029] One end of the evaporator refrigerant piping L14 is connected to the refrigerant outlet of the evaporator 14. The other end of the evaporator refrigerant piping L14 is connected to the refrigerant inlet (suction port) of the compressor 11. In other words, the evaporator refrigerant piping L14 is the piping that connects the refrigerant outlet of the evaporator 14 to the inlet of the compressor 11.

[0030] An accumulator (gas-liquid separator), not shown in the figure, is provided in the evaporator refrigerant piping L14 (between the evaporator 14 and the compressor 11). This prevents the liquid refrigerant from being sent to the compressor 11.

[0031] The compressor 11, condenser 12, expansion valve 13, evaporator 14, and the refrigerant piping connecting these components are installed, for example, outside the vehicle compartment.

[0032] <Configuration of the heat transfer circuit> The heat transfer medium circuit 20 is configured to allow the heat transfer medium HM, which exchanges heat with the refrigerant RF in the condenser 12 and evaporator 14 of the refrigerant circuit 10, to circulate. The heat transfer medium HM is used to heat or cool at least one temperature-controlled object. In this embodiment, the temperature-controlled object is, for example, the air supplied to the vehicle interior for air conditioning. Alternatively, the temperature-controlled object may be an on-board battery device.

[0033] The heat transfer medium circuit 20 includes a pump 21 for pressurizing the heat transfer medium HM, an indoor air conditioning unit (temperature control equipment) 23, a branch valve 24 for branching one flow path into multiple flow paths, and multiple pipes for connecting each of the devices. The heat transfer circuit 20 is filled with a heat transfer medium HM. The filled heat transfer medium HM circulates within the heat transfer circuit 20 according to a cycle (heat transfer loop) corresponding to the operating mode.

[0034] The heat transfer medium HM sealed in the heat transfer circuit 20 is a liquid such as water or brine that circulates through the heat transfer circuit 20 while maintaining a liquid phase state. Examples of brine include a mixture of water and propylene glycol or a mixture of water and ethylene glycol.

[0035] Pump 21 is a device that pumps the heat transfer medium HM in a series of heat transfer medium loops according to the operating mode. The rotational speed of the pump 21 is controlled by the control unit 40.

[0036] One end of the pump outlet pipe L21 is connected to the heat transfer medium outlet (discharge port) of the pump 21. The other end of the pump outlet pipe L21 is connected to the heat transfer medium inlet of the indoor air conditioning unit 23. In other words, the pump outlet piping L21 is the piping that connects the discharge port of the pump 21 to the heat transfer medium inlet of the indoor air conditioning unit 23.

[0037] The interior air conditioning unit 23 is configured to supply conditioned air to the vehicle interior by exchanging heat between air sent by a fan (not shown) and a heat transfer medium HM led from the pump 21 via the pump outlet pipe L21. The rotation speed of the fan (not shown) is controlled by the control unit 40.

[0038] One end of the temperature control equipment outlet pipe L22 is connected to the heat transfer medium outlet of the indoor air conditioning unit 23. The other end of the temperature control equipment outlet pipe L22 is connected to the heat transfer medium inlet (inlet 24i) of the branch valve 24. In other words, the temperature control equipment outlet piping L22 is the piping that connects the heat transfer medium outlet of the indoor air conditioning unit 23 to the inlet 24i of the branch valve 24.

[0039] The branch valve 24 is a three-way valve and has one inlet 24i and two outlets (heat transfer medium outlets) 24o1 and 24o2. The branch valve 24 is a valve that distributes the heat transfer medium HM, which is guided from the indoor air conditioning unit 23 via the temperature control equipment outlet piping L22 and flows in from the inlet 24i, to the respective outlets 24o1 and 24o2 in any desired proportion. The branch valve 24 is controlled by the control unit 40, which adjusts the ratio of the flow rates of the heat transfer medium HM directed to each outlet 24o1 and 24o2. In other words, the ratio of the flow rate of the heat transfer medium HM directed to the condenser 12 to the flow rate of the heat transfer medium HM directed to the evaporator 14 is adjusted.

[0040] One end of the condenser inlet pipe L23 is connected to the outlet 24o1 of the branch valve 24. The other end of the condenser inlet pipe L23 is connected to the heat transfer medium inlet of the condenser 12. In other words, the condenser inlet piping L23 is the piping that connects the outlet 24o1 of the branch valve 24 to the heat transfer medium inlet of the condenser 12.

[0041] One end of the evaporator inlet pipe L24 is connected to the outlet 24o2 of the branch valve 24. The other end of the evaporator inlet pipe L24 is connected to the heat transfer medium inlet of the evaporator 14. In other words, the evaporator inlet piping L24 is the piping that connects the outlet 24o2 of the branch valve 24 to the heat transfer medium inlet of the evaporator 14.

[0042] The condenser 12 is a heat exchanger that exchanges heat between the heat transfer medium HM, which is introduced from the branch valve 24 via the condenser inlet pipe L23, and the refrigerant RF flowing through the refrigerant circuit 10.

[0043] One end of the condenser outlet pipe L25 is connected to the heat transfer medium outlet of the condenser 12. The other end of the condenser outlet pipe L25 is connected to the other end of the evaporator outlet pipe L26, which will be described later. In other words, the condenser outlet pipe L25 is the pipe that connects the heat transfer medium outlet of the condenser 12 to the other end of the evaporator outlet pipe L26.

[0044] The evaporator 14 is a heat exchanger that exchanges heat between the heat transfer medium HM, which is introduced from the branch valve 24 via the evaporator inlet pipe L24, and the refrigerant RF flowing through the refrigerant circuit 10.

[0045] One end of the evaporator outlet pipe L26 is connected to the heat transfer medium outlet of the evaporator 14. The other end of the evaporator outlet pipe L26 is connected to the other end of the condenser outlet pipe L25. In other words, the evaporator outlet pipe L26 is the pipe that connects the heat transfer medium outlet of the evaporator 14 to the other end of the condenser outlet pipe L25.

[0046] The point where the condenser outlet pipe L25 and the evaporator outlet pipe L26 are connected is defined as "junction C". In other words, the condenser outlet pipe L25 and the evaporator outlet pipe L26 merge into one at junction C.

[0047] One end of the pump inlet pipe L27 is connected to the junction C. The other end of the pump inlet pipe L27 is connected to the heat transfer medium inlet (suction port) of the pump 21. In other words, the pump inlet pipe L27 is the pipe that connects the junction C and the suction port of the pump 21.

[0048] <Configuration of the control unit> The control unit 40 is a device that controls the electric motors and electronic equipment installed in each circuit. The control unit 40 is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions are stored in the storage medium in the form of a program, for example. The CPU reads this program into the RAM and performs information processing and calculations to realize the various functions. The program may be pre-installed in the ROM or other storage medium, provided in a state where it is stored in a computer-readable storage medium, or distributed via wired or wireless communication. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memory, etc.

[0049] <Flow of refrigerant and heat transfer medium during steady-state operation in heater mode> The heater mode is suitable for heating when the outside temperature is too low for the heat transfer medium (HM) to absorb heat from the outside air. In heater mode, the heat transfer medium HM is used to transport a heat amount equivalent to the power of the compressor 11 as a heat source to the vehicle compartment (indoor air conditioning unit 23) via the heat transfer medium HM, while avoiding heat loss from the heat transfer medium HM to the outside air. In other words, in heater mode, the heat transfer medium HM that flows out from the evaporator 14 circulates through the heat transfer medium circuit 20 without being led to an outdoor heat exchanger (a heat exchanger that exchanges heat between the heat transfer medium and the outside air) (not shown). This ensures heating capacity even when the outside temperature is significantly below 0°C.

[0050] The high-temperature, high-pressure refrigerant RF, compressed by the compressor 11, is supplied to the condenser 12. In the condenser 12, the refrigerant RF dissipates heat by exchanging heat with the heat transfer medium HM, and the refrigerant RF is condensed and liquefied (it may be supercooled). The liquefied high-pressure refrigerant RF is depressurized by the expansion valve 13 and then supplied to the evaporator 14. In the evaporator 14, the refrigerant RF evaporates by exchanging heat with the heat transfer medium HM, obtaining latent heat of vaporization, and becomes a low-pressure gaseous refrigerant RF. The gasified refrigerant RF is drawn into the compressor 11. The cycle is then repeated.

[0051] The heat transfer medium HM heated by the refrigerant RF in the condenser 12 is led to the confluence C via the condenser outlet pipe L25. Meanwhile, the heat transfer medium HM cooled by the refrigerant RF in the evaporator 14 is led to the confluence C via the evaporator outlet pipe L26. The heat transfer medium HM, which is led to the junction C, is then guided to the indoor air conditioning unit 23 via the pump inlet pipe L27 (pump 21) and the pump outlet pipe L21. The heat transfer medium HM, which is guided to the indoor air conditioning unit 23, provides heat to the air inside the vehicle, for example, to perform heating. The heat transfer medium HM, which has been heated and then cooled, is led to the branch valve 24 via the temperature control equipment outlet pipe L22. The heat transfer medium HM, which is led to the branch valve 24, is distributed in any proportion to the condenser inlet pipe L23 and the evaporator inlet pipe L24. The heat transfer medium HM introduced to the condenser 12 absorbs heat from the refrigerant RF flowing through the condenser 12, liquefying the refrigerant RF. Meanwhile, the heat transfer medium HM introduced to the evaporator 14 transfers the latent heat of vaporization to the refrigerant RF flowing through the evaporator 14, causing the refrigerant RF to evaporate.

[0052] The flow of the heat transfer medium HM described above is generated by the pump 21 and the branch valve 24. Furthermore, as long as the aforementioned flow of the heat transfer medium HM can be generated, the positions of the pump 21 and various valves are not particularly limited.

[0053] <Flow of refrigerant and heat transfer medium during heater mode startup> As shown in Figure 2, when starting up the heater mode, the control unit 40 controls the expansion valve 13 so that the refrigerant RF flowing out of the condenser 12 becomes a gas-liquid two-phase system instead of a liquid phase. As described above, the state of the refrigerant RF flowing out of the evaporator 14 is controlled by adjusting the opening degree of the expansion valve 13. The state of the refrigerant RF flowing out of the condenser 12 is linked to a map based on the opening degree of the expansion valve 13 and the rotational speed of the compressor 11. Therefore, if the target state of the refrigerant RF and the rotational speed of the compressor 11 are known, the opening degree of the expansion valve 13 can be uniquely determined. Normally, the rotational speed of the compressor 11 can be obtained. Thus, by setting the target state of the refrigerant RF, the target opening degree of the expansion valve 13 can be uniquely determined from the map. The control unit 40 performs the necessary processing and calculations for determining the opening degree of the expansion valve 13 using the map, such as reading the map, setting the target refrigerant RF state, and acquiring the rotational speed of the compressor 11.

[0054] Alternatively, the amount of heat exchange of the heat transfer medium HM and the amount of refrigerant RF circulating in the condenser 12 and / or evaporator 14 may be estimated. Based on these estimated amounts of heat exchange and refrigerant circulation, the enthalpy difference of the refrigerant in the condenser 12 and / or evaporator 14 may be estimated. Based on the refrigerant state at the inlet of the condenser 12 and / or the refrigerant state at the outlet of the evaporator 14, taking into account the estimated enthalpy difference, the state of the refrigerant RF flowing out of the condenser 12 may be estimated, and the opening degree of the expansion valve 13 may be controlled accordingly. Here, the amount of heat exchange of the heat transfer medium HM is estimated, for example, from the rotational speed of the pump 21 and the inlet and outlet temperatures of the condenser 12 and / or evaporator 14 (temperature of the heat transfer medium HM). The amount of refrigerant RF circulating is estimated, for example, from the rotational speed and suction pressure of the compressor 11.

[0055] By making the refrigerant RF flowing out of the condenser 12 a gas-liquid two-phase system, the enthalpy difference (specific enthalpy difference) Δh in the evaporator 14 becomes smaller compared to when the expansion valve 13 is controlled so that the refrigerant RF is in the liquid phase (see <Flow of refrigerant and heat transfer medium during steady-state operation in heater mode> above; shown as a dashed line in Figure 2), and the amount of heat exchange required for the evaporation of the refrigerant RF can be reduced. This makes it easier for the pressure and temperature in the evaporator 14 to rise, even when the temperature difference between the refrigerant RF and the heat transfer medium HM is small, allowing the heater mode to be started up earlier.

[0056] In this context, "startup of heater mode" refers to, for example, when the temperature of the heat transfer medium HM is raised when the temperature of the heat transfer medium HM is below a first predetermined temperature and / or when the pressure of the refrigerant RF is raised when the pressure of the refrigerant RF is below a first predetermined pressure, and is typically immediately after the control unit 40 issues a command to execute heater mode.

[0057] The temperature of the heat transfer medium HM refers to the temperature of the heat transfer medium HM at the outlet of the evaporator 14. This temperature is measured, for example, by a temperature sensor (not shown) configured to be measurable by the control unit 40. The refrigerant RF pressure refers to the pressure of the refrigerant RF in the evaporator 14. This pressure is measured, for example, by a pressure sensor (not shown) configured to be measurable by the control unit 40. Note that the temperature of the heat transfer medium HM may also be the temperature of the heat transfer medium HM at the heat transfer medium inlet of the indoor air conditioning unit 23.

[0058] For example, when the temperature of the heat transfer medium HM reaches a second predetermined temperature higher than the first predetermined temperature and / or when the pressure of the refrigerant RF reaches a second predetermined pressure higher than the first predetermined pressure, the control unit 40 terminates the control of the expansion valve 13 (control where the refrigerant RF is in a gas-liquid two-phase state) and switches to normal control (control where the refrigerant RF is in the liquid phase).

[0059] In summary, the control unit 40 determines whether the refrigerant RF flowing out of the condenser 12 will be in a gas-liquid two-phase state or a liquid phase based on the temperature of the heat transfer medium HM and / or the pressure of the refrigerant RF, and controls the expansion valve 13 accordingly.

[0060] Furthermore, because the refrigerant RF flowing out of the condenser 12 is in a two-phase gas-liquid configuration, a reserve tank (gas-liquid separator) is not provided in the condenser refrigerant piping L12.

[0061] <Effects> By making the refrigerant RF flowing out of the condenser 12 a two-phase gas-liquid system, the enthalpy difference Δh in the evaporator 14 becomes smaller compared to the case where the expansion valve 13 is controlled so that the refrigerant RF is in the liquid phase, thereby reducing the amount of heat exchange required for the evaporation of the refrigerant RF. This reduces the temperature difference between the refrigerant RF and the heat transfer medium HM in the evaporator 14, making it easier for the pressure and temperature in the evaporator 14 to rise, and enabling the heater mode to be started up earlier.

[0062] [Modified version of the first embodiment] As shown in Figure 3, the heat transfer fluid circuit 20 may be equipped with a merging valve 25 located at the merging section C instead of the branch valve 24 (see Figure 1). In this case, the section where the branch valve 24 was installed becomes branch section B, where the temperature control equipment outlet piping L22 is branched into the condenser inlet piping L23 and the evaporator inlet piping L24.

[0063] The junction valve 25 is a three-way valve and has two inlets 25i1 and 25i2 and one outlet 25o. The junction valve 25 is a valve that discharges the heat transfer medium HM, which has been taken in at any ratio from each inlet 25i1 and 25i2, from the outlet 25o. The junction valve 25 is controlled by the control unit 40, which adjusts the ratio of the flow rates of the heat transfer medium HM taken in from each inlet 25i1, 25i2.

[0064] The other end of the condenser outlet pipe L25 is connected to the inlet 25i1. The other end of the evaporator outlet pipe L26 is connected to the inlet 25i2. One end of the pump inlet pipe L27 is connected to the outlet 25o. This makes it possible to adjust the ratio between the flow rate of the heat transfer medium HM supplied to the condenser 12 and the flow rate of the heat transfer medium HM supplied to the evaporator 14, similar to the operation of the branch valve 24.

[0065] [Second Embodiment] The temperature control system according to this embodiment differs from the configuration of the heat transfer medium circuit in the first embodiment.

[0066] As shown in Figure 4, the temperature control system 2 includes a refrigerant circuit 10 configured to circulate a refrigerant RF, a heat transfer medium HM configured to circulate a heat transfer medium HM that exchanges heat with the refrigerant RF, and a control unit 40 that controls electric and electronic equipment provided in each circuit.

[0067] <Configuration of refrigerant circuit and control unit> This is identical to the first embodiment. Therefore, a detailed explanation of it will be omitted here.

[0068] <Configuration of the heat transfer circuit> The heat transfer medium circuit 30 is configured to allow the heat transfer medium HM, which exchanges heat with the refrigerant RF in the condenser 12 and evaporator 14 of the refrigerant circuit 10, to circulate.

[0069] The heat transfer medium circuit 30 includes a first pump 31 and a second pump 32 for pumping the heat transfer medium HM, an indoor air conditioning unit (temperature control equipment) 33, a branch valve 34 for branching one flow path into multiple flow paths, a merging valve 35 for merging multiple flow paths into one flow path, and multiple pipes for connecting each of the devices. The heat transfer circuit 20 is filled with a heat transfer medium HM. The filled heat transfer medium HM circulates in the heat transfer circuit 30 according to a cycle (heat transfer loop) corresponding to the operating mode.

[0070] The first pump 31 is a device that pumps the heat transfer medium HM in a series of heat transfer medium loops according to the operating mode. The rotational speed of the first pump 31 is controlled by the control unit 40.

[0071] One end of the first pump outlet pipe L31 is connected to the heat transfer medium outlet (discharge port) of the first pump 31. The other end of the first pump outlet pipe L31 is connected to the heat transfer medium inlet (inlet 35i1) of the junction valve 35. In other words, the first pump outlet piping L31 is the piping that connects the discharge port of the first pump 31 to the inlet 35i1 of the junction valve 35.

[0072] The second pump 32 is a device that pumps the heat transfer medium HM in a series of heat transfer medium loops according to the operating mode. The rotational speed of the second pump 32 is controlled by the control unit 40.

[0073] One end of the second pump outlet pipe L32 is connected to the heat transfer medium outlet (discharge port) of the second pump 32. The other end of the second pump outlet pipe L32 is connected to another heat transfer medium inlet (inlet 35i2) of the junction valve 35. In other words, the second pump outlet piping L32 is the piping that connects the discharge port of the second pump 32 to the inlet 35i2 of the junction valve 35.

[0074] The junction valve 35 is a three-way valve and has two inlets 35i1 and 35i2 and one outlet 35o. The junction valve 35 is a valve that discharges the heat transfer medium HM, which has been taken in at any ratio from each inlet 35i1 and 35i2, from the outlet 35o. The junction valve 35 is controlled by the control unit 40, which adjusts the ratio of the flow rates of the heat transfer medium HM taken in from each inlet 35i1, 35i2.

[0075] One end of the temperature control equipment inlet pipe L33 is connected to the outlet 35o. The other end of the temperature control equipment inlet pipe L33 is connected to the heat transfer medium inlet of the indoor air conditioning unit 33. In other words, the temperature control equipment inlet piping L33 is the piping that connects the outlet 35o to the heat transfer medium inlet of the indoor air conditioning unit 33.

[0076] The interior air conditioning unit 33 is configured to supply conditioned air to the vehicle interior by exchanging heat between air sent by a fan (not shown) and a heat transfer medium HM led from the first pump 31 and / or the second pump 32 via the temperature control equipment inlet piping L33. The rotation speed of the fan (not shown) is controlled by the control unit 40.

[0077] One end of the temperature control equipment outlet pipe L34 is connected to the heat transfer medium outlet of the indoor air conditioning unit 33. The other end of the temperature control equipment outlet pipe L34 is connected to the heat transfer medium inlet (inlet 34i) of the branch valve 34. In other words, the temperature control equipment outlet piping L34 is the piping that connects the heat transfer medium outlet of the indoor air conditioning unit 33 to the inlet 34i of the branch valve 34.

[0078] The branch valve 34 is a three-way valve and has one inlet 34i and two outlets (heat transfer medium outlets) 34o1 and 34o2. The branch valve 34 is a valve that distributes the heat transfer medium HM, which is guided from the indoor air conditioning unit 33 via the temperature control equipment outlet pipe L34 and flows in from the inlet 34i, to the respective outlets 34o1 and 34o2 in any desired proportion. The branch valve 34 is controlled by the control unit 40, which adjusts the flow rate ratio of the heat transfer medium HM that is led to each outlet 34o1, 34o2.

[0079] One end of the condenser inlet pipe L35 is connected to the outlet 34o1 of the branch valve 34. The other end of the condenser inlet pipe L35 is connected to the heat transfer medium inlet of the condenser 12. In other words, the condenser inlet piping L35 is the piping that connects the outlet 34o1 of the branch valve 34 to the heat transfer medium inlet of the condenser 12.

[0080] One end of the evaporator inlet pipe L36 is connected to the outlet 34o2 of the branch valve 34. The other end of the evaporator inlet pipe L36 is connected to the heat transfer medium inlet of the evaporator 14. In other words, the evaporator inlet piping L36 is the piping that connects the outlet 34o2 of the branch valve 34 to the heat transfer medium inlet of the evaporator 14.

[0081] The condenser 12 is a heat exchanger that exchanges heat between the heat transfer medium HM, which is introduced from the branch valve 34 via the condenser inlet pipe L35, and the refrigerant RF flowing through the refrigerant circuit 10.

[0082] One end of the condenser outlet pipe L37 is connected to the heat transfer medium outlet of the condenser 12. The other end of the condenser outlet pipe L37 is connected to the heat transfer medium inlet (suction port) of the first pump 31. In other words, the condenser outlet piping L37 is the piping that connects the heat transfer medium outlet of the condenser 12 to the inlet of the first pump 31.

[0083] The evaporator 14 is a heat exchanger that exchanges heat between the heat transfer medium HM, which is introduced from the branch valve 34 via the evaporator inlet pipe L36, and the refrigerant RF flowing through the refrigerant circuit 10.

[0084] One end of the evaporator outlet pipe L38 is connected to the heat transfer medium outlet of the evaporator 14. The other end of the evaporator outlet pipe L38 is connected to the heat transfer medium inlet (suction port) of the second pump 32. In other words, the evaporator outlet piping L38 is the piping that connects the heat transfer medium outlet of the evaporator 14 to the inlet of the second pump 32.

[0085] <Flow of refrigerant and heat transfer medium during steady-state operation in heater mode> The heater mode is suitable for heating when the outside temperature is too low for the heat transfer medium (HM) to absorb heat from the outside air. In heater mode, the heat transfer medium HM is used to transport a heat amount equivalent to the power of the compressor 11 as a heat source to the vehicle compartment (indoor air conditioning unit 33) via the heat transfer medium HM, while avoiding heat loss from the heat transfer medium HM to the outside air. In other words, in heater mode, the heat transfer medium HM that flows out from the evaporator 14 circulates through the heat transfer medium circuit 20 without being led to an outdoor heat exchanger (a heat exchanger that exchanges heat between the heat transfer medium and the outside air) (not shown). This ensures heating capacity even when the outside temperature is significantly below 0°C.

[0086] The refrigerant RF is compressed in the compressor 11 and supplied to the condenser 12 as high-temperature, high-pressure refrigerant RF. In the condenser 12, the refrigerant RF dissipates heat by exchanging heat with the heat transfer medium HM, causing the refrigerant RF to condense and liquefy, and further to be supercooled. The liquefied high-pressure refrigerant RF is reduced in pressure by the expansion valve 13 and then supplied to the evaporator 14. In the evaporator 14, the refrigerant RF evaporates by exchanging heat with the heat transfer medium HM, obtaining latent heat of vaporization, and becomes a low-pressure gaseous refrigerant RF. The gasified refrigerant RF is drawn into the compressor 11. The cycle is then repeated.

[0087] The heat transfer medium HM heated by the refrigerant RF in the condenser 12 is led to the junction valve 35 via the condenser outlet pipe L37 (and the first pump 31) and the first pump outlet pipe L31. Meanwhile, the heat transfer medium HM cooled by the refrigerant RF in the evaporator 14 is led to the junction valve 35 via the evaporator outlet pipe L38 (and the second pump 32) and the second pump outlet pipe L32. The heat transfer medium HM, which is led to the junction valve 35, is then led to the indoor air conditioning unit 33 via the temperature control equipment inlet piping L33. The heat transfer medium HM, which is guided to the indoor air conditioning unit 33, provides heat to the air inside the vehicle, for example, to perform heating. The heat transfer medium HM, which has been heated and then cooled, is led to the branch valve 34 via the temperature control equipment outlet pipe L34. The heat transfer medium HM, which is led to the branch valve 34, is distributed in arbitrary proportions to the condenser inlet pipe L35 and the evaporator inlet pipe L36. The heat transfer medium HM introduced to the condenser 12 absorbs heat from the refrigerant RF flowing through the condenser 12, liquefying the refrigerant RF. Meanwhile, the heat transfer medium HM introduced to the evaporator 14 transfers the latent heat of vaporization to the refrigerant RF flowing through the evaporator 14, causing the refrigerant RF to evaporate.

[0088] The flow of the heat transfer medium HM described above is generated by the first pump 31, the second pump 32, the branch valve 34, and the junction valve 35. Furthermore, as long as the aforementioned flow of the heat transfer medium HM can be generated, the positions of the first pump 31, the second pump 32, and the various valves are not particularly limited.

[0089] <Flow of refrigerant and heat transfer medium during heater mode startup> This is identical to the first embodiment. Therefore, a detailed explanation of it will be omitted here.

[0090] [Modification 1 of the second embodiment]

[0091] As shown in Figure 5, the condenser outlet pipe L37 and the evaporator outlet pipe L38 may be connected by a connecting pipe L39.

[0092] A reserve tank 36 is provided in the connecting pipe L39. The reserve tank 36 is a container that accepts heat transfer fluid HM when its volume expands due to a rise in temperature, exceeding the volume of the piping of the heat transfer fluid circuit 30 (limited to the part where the heat transfer fluid HM loops). Conversely, when the volume of heat transfer fluid HM decreases due to a drop in temperature, heat transfer fluid HM is supplied from the reserve tank 36 to the piping of the heat transfer fluid circuit 30, so that the piping of the heat transfer fluid circuit 30 is maintained in a state where it is filled with heat transfer fluid HM.

[0093] When the pressure of the heat transfer medium HM in the condenser outlet pipe L37 and the pressure of the heat transfer medium HM in the evaporator outlet pipe L38 are balanced, no flow of the heat transfer medium HM is formed in the connecting pipe L39. On the other hand, if the pressure of the heat transfer medium HM in the condenser outlet pipe L37 and the pressure of the heat transfer medium HM in the evaporator outlet pipe L38 are not balanced, the pressure equalizing effect of the connecting pipe L39 will create a flow of heat transfer medium HM from one outlet pipe (e.g., the evaporator outlet pipe L38) to the other outlet pipe (e.g., the condenser outlet pipe L37).

[0094] [Modification 2 of the second embodiment] As shown in Figure 6, for example, the second pump 32 may be stopped. In this case, the heat transfer medium HM that flows out of the evaporator 14 does not pass through the second pump 32, but is guided to the condenser outlet pipe L37 (and consequently to the first pump 31) via the evaporator outlet pipe L38 and connecting pipe L39. Therefore, the flow of the heat transfer medium HM is generated solely by the first pump 31.

[0095] Alternatively, the first pump 31 may be stopped and the second pump 32 may be operated.

[0096] [Note] The temperature control systems and control methods for each embodiment described above can be understood, for example, as follows.

[0097] A temperature control system (1,2) according to a first aspect of this disclosure comprises a compressor (11), a high-pressure side heat exchanger (12), a depressurization unit (13), and a low-pressure side heat exchanger (14), a refrigerant circuit (10) through which a refrigerant (RF) circulates, a heat transfer medium (HM) circulates through which heat is exchanged with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger, and a control unit (40), wherein the heat transfer medium circuit includes a temperature control device (23) that heats the temperature-controlled object using the heat transfer medium. ,33) The control unit has a heater mode in which it mixes the heat transfer medium that has flowed out of the high-pressure heat exchanger with the heat transfer medium that has flowed out of the low-pressure heat exchanger, flows the mixed heat transfer medium into the high-pressure heat exchanger and the low-pressure heat exchanger, and flows the heat transfer medium that has flowed out of the high-pressure heat exchanger into the temperature control equipment, and controls the depressurization unit by determining whether the refrigerant flowing out of the high-pressure heat exchanger is in a gas-liquid two-phase or liquid phase.

[0098] In the temperature control system according to this embodiment, the control unit determines whether the refrigerant flowing out of the high-pressure heat exchanger is in a gas-liquid two-phase state or a liquid phase based on the temperature of the heat transfer medium and / or the pressure of the refrigerant, and controls the pressure reduction unit. For example, when the refrigerant is in a gas-liquid two-phase state when starting up the heater mode, the enthalpy difference in the low-pressure heat exchanger becomes smaller compared to when the pressure reduction unit is controlled so that the refrigerant is in the liquid phase (for example, when the refrigerant flowing out of the high-pressure heat exchanger is subcooled), and the amount of heat exchange required for the evaporation of the refrigerant can be reduced. As a result, the temperature difference between the refrigerant and the heat transfer medium becomes smaller, the pressure and temperature in the evaporator rise more easily, and the heater mode can be started up earlier.

[0099] In the first embodiment, the temperature control system according to a second aspect of the present disclosure controls the pressure reduction unit so that the refrigerant flowing out of the high-pressure side heat exchanger becomes a gas-liquid two-phase system when the temperature of the heat transfer medium is below a first predetermined temperature.

[0100] In a third aspect of the present disclosure, the temperature control system, in a second aspect, controls the pressure reduction unit so that the refrigerant flowing out of the high-pressure heat exchanger becomes a gas-liquid two-phase system when the temperature of the heat transfer medium is higher than a second predetermined temperature, which is higher than the first predetermined temperature.

[0101] In a fourth aspect of the present disclosure, the temperature control system, in the first or second aspect, controls the pressure reduction unit so that the refrigerant flowing out of the high-pressure heat exchanger becomes liquid when the pressure of the refrigerant in the low-pressure heat exchanger is less than or equal to a first predetermined pressure.

[0102] In a fifth aspect of the present disclosure, the temperature control system, in a fourth aspect, controls the pressure reduction unit so that the refrigerant flowing out of the high-pressure heat exchanger becomes liquid when the pressure of the refrigerant in the low-pressure heat exchanger is higher than a second predetermined pressure, which is higher than the first predetermined pressure.

[0103] In any of the first, second, and fourth embodiments of the temperature control system according to the sixth aspect of the present disclosure, the control unit estimates the state of the refrigerant flowing out of the high-pressure heat exchanger based on the temperature of the heat medium at the inlet and outlet of the high-pressure heat exchanger and / or the temperature of the heat medium at the inlet and outlet of the low-pressure heat exchanger, the rotational speed of the compressor and the suction pressure, and controls the pressure reduction unit so that the state of the refrigerant becomes a gas-liquid two-phase system.

[0104] A temperature control system according to a seventh aspect of the present disclosure comprises a refrigerant circuit through which a refrigerant circulates, having a compressor, a high-pressure side heat exchanger, a pressure reducing unit, and a low-pressure side heat exchanger, and a heat transfer medium circuit through which a heat transfer medium that exchanges heat with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger circulates, wherein the heat transfer medium circuit has a temperature control device that heats a temperature control target using the heat transfer medium, and a control method for the temperature control system comprising: mixing the heat transfer medium discharged from the high-pressure side heat exchanger with the heat transfer medium discharged from the low-pressure side heat exchanger, allowing the mixed heat transfer medium to flow into the high-pressure side heat exchanger and the low-pressure side heat exchanger, and allowing the heat transfer medium discharged from the high-pressure side heat exchanger to flow into the temperature control device, wherein in a heater mode heat transfer medium loop, the control method determines whether the refrigerant discharged from the high-pressure side heat exchanger is in a gas-liquid two-phase or liquid phase and adjusts the pressure reducing unit. [Explanation of symbols]

[0105] 1,2 Temperature control system 10 Refrigerant Circuit 11 Compressor 12. Condenser (High-pressure side heat exchanger) 13. Expansion valve (pressure reducing section) 14. Evaporator (low-pressure heat exchanger) L11 Compressor Refrigerant Piping L12 Condenser Refrigerant Piping L13 Expansion valve refrigerant piping L14 Evaporator Refrigerant Piping 20 Heat carrier circuit 21 pumps 23. Indoor air conditioning units (temperature control equipment) 24 Branch valve 24i inlet 24o1 Outlet 24o2 Outlet 25. Merging valve 25i1 Inlet 25i2 Inlet 25o outlet L21 Pump outlet piping L22 Temperature controller outlet piping L23 Condenser inlet piping L24 Evaporator Inlet Piping L25 Condenser outlet piping L26 Evaporator Outlet Piping L27 Pump Inlet Piping 30 Heat carrier circuit 31 Pump No. 1 32. Pump No. 2 33. Indoor air conditioning unit (temperature control equipment) 34 Branch valve 34i inlet 34o1 Outlet 34o2 Outlet 35. Merging valve 35i1 Inlet 35i2 Inlet 35o outlet 36 Reserve Tank L31 First pump outlet piping L32 Second pump outlet piping L33 Temperature control equipment inlet piping L34 Temperature controller outlet piping L35 Condenser Inlet Piping L36 Evaporator Inlet Piping L37 Condenser outlet piping L38 Evaporator Outlet Piping L39 Connection Piping 40 Control Unit B Branch C Confluence

Claims

1. A refrigerant circuit comprising a compressor, a high-pressure side heat exchanger, a depressurization section, and a low-pressure side heat exchanger, through which the refrigerant circulates, A heat transfer medium circuit through which the heat transfer medium that exchanges heat with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger circulates, Control unit and Equipped with, The heat transfer medium circuit includes a temperature control device that heats the temperature-controlled object using the heat transfer medium. The control unit, In a heater mode in which the heat transfer medium discharged from the high-pressure heat exchanger is mixed with the heat transfer medium discharged from the low-pressure heat exchanger, the mixed heat transfer medium is fed into the high-pressure heat exchanger and the low-pressure heat exchanger, and the heat transfer medium discharged from the high-pressure heat exchanger is fed into the temperature control device, The pressure reduction unit is controlled by determining whether the refrigerant flowing out from the high-pressure side heat exchanger is in a gas-liquid two-phase or liquid phase. Temperature control system.

2. The control unit controls the pressure reduction unit so that the refrigerant flowing out of the high-pressure heat exchanger becomes a gas-liquid two-phase system when the temperature of the heat transfer medium is below a first predetermined temperature. The temperature control system according to claim 1.

3. The control unit controls the pressure reduction unit so that the refrigerant flowing out of the high-pressure heat exchanger becomes a gas-liquid two-phase system when the temperature of the heat transfer medium is higher than the first predetermined temperature (a second predetermined temperature or higher). The temperature control system according to claim 2.

4. The control unit controls the pressure reduction unit so that the refrigerant flowing out of the high-pressure heat exchanger becomes liquid when the pressure of the refrigerant in the low-pressure heat exchanger is below a first predetermined pressure. The temperature control system according to claim 1.

5. The control unit controls the pressure reduction unit so that the refrigerant flowing out of the high-pressure heat exchanger becomes liquid when the pressure of the refrigerant in the low-pressure heat exchanger is higher than the first predetermined pressure (a second predetermined pressure or higher). The temperature control system according to claim 4.

6. The control unit estimates the state of the refrigerant flowing out of the high-pressure heat exchanger based on the temperature of the heat medium at the inlet and outlet of the high-pressure heat exchanger and / or the temperature of the heat medium at the inlet and outlet of the low-pressure heat exchanger, the rotational speed of the compressor, and the suction pressure, and controls the pressure reduction unit so that the state of the refrigerant is a gas-liquid two-phase system. A temperature control system according to any one of claims 1, 2, and 4.

7. A refrigerant circuit comprising a compressor, a high-pressure side heat exchanger, a depressurization section, and a low-pressure side heat exchanger, through which the refrigerant circulates, A heat transfer medium circuit through which the heat transfer medium that exchanges heat with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger circulates, Equipped with, The heat transfer circuit includes a temperature control device that heats the object to be temperature controlled using the heat transfer medium. A method for controlling a temperature control system, In a heater mode heat transfer medium loop in which the heat transfer medium flowing out from the high-pressure heat exchanger is mixed with the heat transfer medium flowing out from the low-pressure heat exchanger, the mixed heat transfer medium is fed into the high-pressure heat exchanger and the low-pressure heat exchanger, and the heat transfer medium flowing out from the high-pressure heat exchanger is fed into the temperature control equipment, the pressure reduction section is adjusted by determining whether the refrigerant flowing out from the high-pressure heat exchanger is in a gas-liquid two-phase or liquid phase. A method for controlling a temperature control system.

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