Temperature control system and its control method

Abstract

The present invention provides a temperature control system that can lower the temperature of the compressor's electrical equipment while suppressing a decrease in heating capacity in the compressor heat source mode. [Solution] The vehicle air conditioning system 1 comprises a refrigerant circuit 3, a heat transfer medium circuit 5 through which a heat transfer medium circulates, and a control unit that controls the refrigerant circuit 3 and the heat transfer medium circuit 5. The heat transfer medium circuit 5 comprises a first indoor heat exchanger 18 that exchanges heat between the heat transfer medium and the air inside the vehicle, and an outdoor heat exchanger that exchanges heat between the heat transfer medium and the outside air. The electrical equipment for driving the compressor 10 is cooled by the refrigerant circulating in the refrigerant circuit. The control unit has a heater mode in which the compressor 10 is used as a heat source to guide the hot water flowing out of the condenser 11 to the first indoor heat exchanger 18 to heat the air inside the vehicle, and an electrical equipment de-temperatureing mode in which, in heater mode, the pressure of the refrigerant circulating in the evaporator 13 is reduced.

Description

Technical Field

[0006] , ,

[0005] ,

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

Background Art

[0002] Patent Document 1 discloses a vehicle thermal management device that controls the cooling water temperature for cooling an inverter of a traveling electric motor.

Prior Art Documents

Patent Documents

[0003] <00​​​​​​​​​​​​​​​​​​​​​This disclosure is made in view of these circumstances and aims to provide a temperature control system and a control method thereof that can lower the temperature of the electrical equipment of a compressor while suppressing a decrease in heating capacity in the compressor heat source mode. [Means for solving the problem]

[0007] A temperature control system according to one aspect of the present disclosure comprises a refrigerant circuit having a compressor for compressing a refrigerant, a high-pressure heat exchanger for releasing heat from the refrigerant compressed by the compressor, an expansion valve for expanding the refrigerant released heat from the high-pressure heat exchanger, and a low-pressure heat exchanger for evaporating the refrigerant expanded by the expansion valve; a heat transfer medium circuit through which a heat transfer medium that exchanges heat with the refrigerant in the high-pressure heat exchanger and the low-pressure heat exchanger circulates; and a control unit for controlling the refrigerant circuit and the heat transfer medium circuit, wherein the heat transfer medium circuit comprises a heat transfer medium The system comprises a temperature control device that exchanges heat between the compressor and the temperature-controlled object, and an outdoor heat exchanger that exchanges heat between the heat transfer medium and the outside air. The electrical equipment for driving the compressor is cooled by the refrigerant circulating in the refrigerant circuit. The control unit has a compressor heat source mode in which the compressor is used as a heat source to guide the heat transfer medium flowing out of the high-pressure side heat exchanger to the temperature control device to heat the temperature-controlled object, and an electrical equipment de-temperatureing mode in which, in the compressor heat source mode, the pressure of the refrigerant circulating in the low-pressure side heat exchanger is reduced.

[0008] A control method for a temperature control system according to one aspect of the present disclosure is a control method for a temperature control system comprising: a refrigerant circuit having a compressor for compressing a refrigerant; a high-pressure side heat exchanger for releasing heat from the refrigerant compressed by the compressor; an expansion valve for expanding the refrigerant that has released heat from the high-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 is a heat transfer medium The system comprises a temperature control device that exchanges heat between a body and a temperature-controlled object, and an outdoor heat exchanger that exchanges heat between a heat transfer medium and outside air. The electrical equipment for driving the compressor is cooled by the refrigerant circulating in the refrigerant circuit and has a compressor heat source mode in which the compressor is used as a heat source to guide the heat transfer medium flowing out of the high-pressure side heat exchanger to the temperature control device to heat the temperature-controlled object, and an electrical equipment de-temperatureing mode in which, in the compressor heat source mode, the pressure of the refrigerant circulating in the low-pressure side heat exchanger is reduced. [Effects of the Invention]

[0009] In compressor heat source mode, it is possible to lower the temperature of the compressor's electrical components while suppressing a decrease in heating capacity. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing a vehicle air conditioning system according to the first embodiment of this disclosure, specifically in heater mode. [Figure 2] This is a schematic diagram showing a vehicle air conditioning system according to a second embodiment of the present disclosure, specifically illustrating the heat pump mode. [Figure 3] Figure 2 is a schematic diagram showing the heater mode of the vehicle air conditioning system. [Figure 4] This graph shows the relationship between compressor power and compressor rotational speed. [Figure 5] This is a schematic diagram showing a modified example 1 of Figure 3. [Figure 6] This is a schematic diagram showing a modified example 2 of Figure 3. [Figure 7] This is a schematic diagram showing a modified example 3 of Figure 3. [Figure 8]This is a schematic diagram showing a vehicle air conditioning system according to a third embodiment of the present disclosure, specifically illustrating the hot gas mode. [Modes for carrying out the invention]

[0011] Embodiments relating to this disclosure will be described below with reference to the drawings. [First Embodiment] The first embodiment of this disclosure will be described below with reference to Figure 1. Figure 1 shows a schematic diagram of the vehicle air conditioning system (temperature control system) 1 according to this embodiment. The vehicle air conditioning system 1 comprises a refrigerant circuit 3, a hot water circuit (heat transfer medium circuit) 5, and a chilled water circuit (heat transfer medium circuit) 7.

[0012] The refrigerant circuit 3 comprises a compressor 10 for compressing the refrigerant, a condenser (high-pressure side heat exchanger) 11 for condensing (or releasing heat from) the refrigerant compressed by the compressor 10, an expansion valve 12 for expanding the refrigerant condensed in the condenser 11, and an evaporator (low-pressure side heat exchanger) 13 for evaporating the refrigerant expanded in the expansion valve 12, thus constituting a refrigeration cycle. The operation of the refrigerant circuit 3 is controlled by a control unit (not shown).

[0013] For example, a scroll compressor or a rotary compressor can be used as the compressor 10. The compressor 10 includes an electric motor that drives the compression mechanism and an inverter unit that controls the rotational speed of the electric motor. The electric motor is housed in a housing that contains the compression mechanism. The structure is such that the electric motor is cooled as the low-pressure refrigerant drawn into the compressor 10 flows around it. The inverter unit is attached to the housing and is cooled by heat conduction through the housing. In this way, the electric motor, inverter unit, and other electrical equipment for driving the compressor 10 are cooled by the refrigerant (low-pressure refrigerant) introduced from the evaporator 13.

[0014] The electric motor is provided with an electric motor temperature sensor that measures the temperature of the electric motor. The inverter unit is provided with an inverter unit temperature sensor that measures the temperature of the inverter unit. Also, a current sensor that measures the current value input to the electric motor is provided. The measured values of the electric motor temperature sensor, the inverter unit temperature sensor, and the current sensor are transmitted to the control unit.

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

[0016] The hot water circuit 5 is provided with a confluence three-way valve 23 and a hot water pump 30 on the upstream side of the first indoor heat exchanger 18. A distribution three-way valve 25 is provided on the downstream side of the first indoor heat exchanger 18 of the hot water circuit 5. The opening degrees of the confluence three-way valve 23 and the distribution three-way valve 25 are controlled by the control unit. The rotation speed, that is, the flow rate of the hot water pump 30 is controlled by the control unit.

[0017] In the confluence three-way valve 23, hot water and cold water are made to confluence, and the confluent hot water is led to the first indoor heat exchanger 18. In the distribution three-way valve 25, the hot water led from the first indoor heat exchanger 18 is distributed to the condenser 11 and the evaporator 13. Note that only one of the confluence three-way valve 23 and the distribution three-way valve 25 may be provided.

[0018] The control unit is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium, etc. And a series of processes for realizing various functions are stored in a storage medium, etc. in the form of a program as an example. The CPU reads this program into the RAM, etc. and executes information processing and arithmetic operations, thereby realizing various functions. Note that the program may be in a form pre-installed in the ROM or other storage media, a form provided in a state stored in a computer-readable storage medium, a form distributed via wired or wireless communication means, etc. A computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, etc.

[0019] Next, the operation of the vehicle air conditioner 1 with the above configuration will be described. <Heater mode> FIG. 1 shows the heater mode (compressor heat source mode). The heater mode is used when the outside air temperature is low, such as in winter, and the warm water flowing out of the condenser 11 with the compressor 10 as the heat source is guided to the first indoor heat exchanger 18 to heat the indoor air.

[0020] In the refrigerant circuit 3, the refrigerant compressed by the compressor 10 is sent to the condenser 11 and condensed. When the refrigerant condenses, the latent heat of condensation is given to the warm water, which is the heat medium flowing through the condenser 11, to heat it.

[0021] The liquid refrigerant exiting the condenser 11 is decompressed by the expansion valve 12 and guided to the evaporator 13. In the evaporator 13, the refrigerant evaporates, and the latent heat of evaporation is taken from the cold water, which is the heat medium flowing through the evaporator 13, and the cold water is cooled.

[0022] The hot water heated in the condenser 11 is led to the three-way merging valve 23, where it merges with the cold water cooled in the evaporator 13. After merging in the three-way merging valve 23, the hot water is led by the hot water pump 30 to the first indoor heat exchanger 18. In the first indoor heat exchanger 18, the air in the vehicle interior is heated by heat exchange with it.

[0023] The hot water exiting the first indoor heat exchanger 18 is led to the distribution three-way valve 25, where some of the hot water is returned to the condenser 11 and the remaining hot water is returned to the evaporator 13.

[0024] As described above, in the heater mode shown in Figure 1, hot water heated in the condenser 11 is mixed with cold water introduced from the evaporator 13, and the resulting hot water is introduced into the first indoor heat exchanger 18. The hot water that exits the first indoor heat exchanger 18 is then introduced into the condenser 11 and the evaporator 13.

[0025] <Electrical equipment temperature reduction mode> Next, we will describe the electrical equipment temperature reduction mode for reducing the temperature of the electrical equipment that drives the compressor 10. The electrical equipment temperature reduction mode is performed during the heater mode described above.

[0026] The control unit determines that the temperature of the electrical equipment has exceeded the allowable temperature when the measured value of the electric motor temperature sensor exceeds a predetermined value, and / or the measured value of the inverter unit temperature sensor exceeds a predetermined value, and / or the current value exceeds a predetermined value, and switches to the electrical equipment cooling mode.

[0027] First, the control unit controls the opening of the three-way distribution valve 25 by command, reducing the flow rate of hot water to the evaporator 13. As a result, the flow rate of hot water to the evaporator 13 decreases, lowering the refrigerant pressure in the evaporator 13. The decrease in refrigerant pressure also lowers the temperature of the refrigerant flowing into the compressor, which in turn lowers the temperature of electrical equipment such as the electric motor and inverter.

[0028] When the measured value from the electric motor temperature sensor and / or the measured value from the inverter unit temperature sensor and / or the current value meet a predetermined allowable value, the control unit maintains the refrigerant pressure of the evaporator 13 at a constant value. This ensures that the temperature of the electrical equipment is kept below the allowable value.

[0029] The effects and advantages of this embodiment, as described above, are as follows. In heater mode, if the temperature of the electrical equipment in the compressor 10 rises, the flow rate of hot water to the evaporator 13 is reduced to lower the pressure of the refrigerant circulating in the evaporator 13. This lowers the pressure of the low-pressure refrigerant and reduces the temperature of the refrigerant flowing into the compressor, thereby promoting the cooling of the electrical equipment cooled by the refrigerant. In this way, it is not necessary to reduce the rotational speed of the compressor 10, so the temperature of the electrical equipment in the compressor 10 can be lowered while suppressing a decrease in heating capacity.

[0030] [Second Embodiment] Next, a second embodiment of this disclosure will be described with reference to Figure 2. The vehicle air conditioning system 1 shown in Figure 2 has a different configuration of the heat transfer medium circuit compared to the first embodiment. In the following description, the configurations that differ from the first embodiment will be described, and the same components will be denoted by the same reference numerals and their descriptions will be omitted.

[0031] The hot water circuit 5 is a flow path that primarily supplies hot water heated in the condenser 11 to the first indoor heat exchanger (temperature control equipment) 18, and returns the hot water that flows out of the first indoor heat exchanger 18 to the condenser 11.

[0032] The hot water circuit 5 includes a hot water pump 30 connected to a hot water outlet pipe 19. The cold water circuit 7 includes a cold water pump 32 connected to a cold water outlet pipe 21. The rotational speed, i.e., the flow rate, of the hot water pump 30 and the cold water pump 32 is controlled by the control unit.

[0033] The hot water discharge pipe 35 connected to the hot water pump 30 and the cold water discharge pipe 36 connected to the cold water pump 32 are connected to the first indoor heat exchanger 18, the second indoor heat exchanger 22, and the outdoor heat exchanger 50.

[0034] An upstream three-way valve 52a is provided in the first indoor heat exchanger inlet piping 41 on the upstream side of the first indoor heat exchanger 18, and a downstream three-way valve 52b is provided in the first indoor heat exchanger outlet piping 42 on the downstream side of the first indoor heat exchanger 18. The opening degree of the upstream three-way valve 52a is controlled by the control unit and allows hot water from the hot water pump 30 and cold water from the cold water pump 32 to flow to the first indoor heat exchanger 18. The downstream three-way valve 52b is controlled by the control unit and allows hot water or cold water that has flowed out of the first indoor heat exchanger 18 to flow to the hot water return piping 44 and the cold water return piping 45. The opening degrees of the upstream three-way valve 52a and the downstream three-way valve 52b are controlled synchronously by a single actuator. This disclosure is not limited to the three-way valves described above, and other three-way valves or two-way valves may be combined.

[0035] An upstream three-way valve 53a is provided in the second indoor heat exchanger inlet piping 24 on the upstream side of the second indoor heat exchanger 22, and a downstream three-way valve 53b is provided in the second indoor heat exchanger outlet piping 27 on the downstream side of the second indoor heat exchanger 22. The opening degree of the upstream three-way valve 53a is controlled by the control unit and allows hot water from the hot water pump 30 and cold water from the cold water pump 32 to flow to the second indoor heat exchanger 22. The downstream three-way valve 53b is controlled by the control unit and allows hot water or cold water that has flowed out of the second indoor heat exchanger 22 to flow to the hot water return piping 44 and the cold water return piping 45. The opening degrees of the upstream three-way valve 53a and the downstream three-way valve 53b are controlled synchronously by a single actuator. Note that this disclosure is not limited to the three-way valves described above, and other three-way valves or two-way valves may be combined.

[0036] An outdoor heat exchanger upstream three-way valve 56a is provided in the outdoor heat exchanger inlet piping 54 on the upstream side of the outdoor heat exchanger 50, and an outdoor heat exchanger downstream three-way valve 56b is provided in the outdoor heat exchanger outlet piping 55 on the downstream side of the outdoor heat exchanger 50. The opening degree of the outdoor heat exchanger upstream three-way valve 56a is controlled by the control unit and allows hot water from the hot water pump 30 and cold water from the cold water pump 32 to flow to the outdoor heat exchanger 50. The outdoor heat exchanger downstream three-way valve 56b is controlled by the control unit and allows hot water or cold water that has flowed out of the outdoor heat exchanger 50 to flow to the hot water return piping 44 and the cold water return piping 45. The opening degrees of the outdoor heat exchanger upstream three-way valve 56a and the outdoor heat exchanger downstream three-way valve 56b are controlled synchronously by a single actuator. Note that this disclosure is not limited to the three-way valves described above, and other three-way valves or two-way valves may be combined.

[0037] A heat transfer medium bypass pipe 47 is provided between the hot water outlet pipe 19 upstream of the hot water pump 30 and the cold water outlet pipe 21 upstream of the cold water pump 32. Hot water flows from the hot water circuit 5 to the cold water circuit 7, or cold water flows from the cold water circuit 7 to the hot water circuit 5, through the heat transfer medium bypass pipe 47. A reserve tank 48 for storing hot water or cold water is provided in the heat transfer medium bypass pipe 47.

[0038] Next, the operation of the heat pump mode and heater mode using the vehicle air conditioning system 1 with the above configuration will be described. <Heat pump mode> The heat pump mode will be explained using Figure 2. In Figure 2 and subsequent figures, solid lines in the hot water circuit 5 and chilled water circuit 7 indicate that no heat transfer medium flows through them. Dashed lines indicate that chilled water flows, and dashed lines indicate that hot water flows.

[0039] The heat pump mode is mainly used in winter, and the heat pump operation of the refrigerant circuit 3 absorbs heat from the outside air in the outdoor heat exchanger 50 and heats the air inside the vehicle in the first indoor heat exchanger 18.

[0040] In the refrigerant circuit 3, the refrigerant compressed by the compressor 10 is sent to the condenser 11 where it condenses. As the refrigerant condenses, the latent heat of condensation is transferred to the hot water, which is the heat transfer medium flowing through the condenser 11, causing it to heat up.

[0041] The liquid refrigerant exiting the condenser 11 is depressurized by the expansion valve 12 and guided to the evaporator 13. In the evaporator 13, the refrigerant evaporates, and the latent heat of vaporization is absorbed from the chilled water, which is the heat transfer medium circulating in the evaporator 13, thereby cooling the chilled water.

[0042] The hot water heated in the condenser 11 is guided by the hot water pump 30 through the upstream three-way valve 52a of the first indoor heat exchanger to the first indoor heat exchanger 18. In the first indoor heat exchanger 18, the air in the vehicle interior is heated by heat exchange with it.

[0043] The hot water that exits the first indoor heat exchanger 18 is returned to the condenser 11 via the hot water return pipe 44 through the three-way valve 52b downstream of the first indoor heat exchanger.

[0044] The chilled water cooled in the evaporator 13 is guided by the chilled water pump 32 through the three-way valve 56a upstream of the outdoor heat exchanger to the outdoor heat exchanger 50. In the outdoor heat exchanger 50, the chilled water is heated by absorbing heat from the outside air.

[0045] The chilled water that exits the outdoor heat exchanger 50 is returned to the evaporator 13 through the three-way valve 56b downstream of the outdoor heat exchanger and the chilled water return pipe 45.

[0046] <Heater Mode> Figure 3 shows the heater mode. Unlike the heat pump mode, in the heater mode, similar to the first embodiment, the chilled water flowing out of the evaporator 13 is not led to the outdoor heat exchanger 50, but is mixed with hot water and then led to the first indoor heat exchanger 18. The hot water flowing out of the first indoor heat exchanger 18 is distributed to the condenser 11 and the evaporator 13.

[0047] The heater mode is activated by a command from the control unit when the outside air temperature drops further during heat pump mode, or when the amount of heat absorbed by the outdoor heat exchanger 50 falls below a predetermined value.

[0048] The control unit commands the chilled water pump 32 to stop, and only the hot water pump 30 to operate. The chilled water flowing out of the evaporator 13 passes through the heat transfer medium bypass pipe 47 and mixes with the hot water flowing through the hot water outlet pipe 19. The mixed hot water is then guided through the upstream three-way valve 52a of the first indoor heat exchanger to the first indoor heat exchanger 18. In the first indoor heat exchanger 18, the air in the vehicle interior is heated by exchanging heat with it.

[0049] The hot water exiting the first indoor heat exchanger 18 passes through the downstream three-way valve 52b of the first indoor heat exchanger and is distributed to the hot water return pipe 44 and the chilled water return pipe 45. Some of the hot water is returned to the condenser 11, and the remaining hot water is returned to the evaporator 13.

[0050] For the outdoor heat exchanger 50, the upstream three-way valve 56a and the downstream three-way valve 56b are completely closed to prevent the flow of the heat transfer medium (hot water or cold water).

[0051] <Electrical equipment temperature reduction mode> Next, an electrical equipment cooling mode for reducing the temperature of the electrical equipment that drives the compressor 10 will be described. The electrical equipment cooling mode is performed during the heater mode described above, similar to the first embodiment.

[0052] The control unit determines that the temperature of the electrical equipment has exceeded the allowable temperature when the measured value of the electric motor temperature sensor exceeds a predetermined value, and / or the measured value of the inverter unit temperature sensor exceeds a predetermined value, and / or the current value exceeds a predetermined value, and switches to the electrical equipment cooling mode.

[0053] First, the control unit controls the opening of the three-way valve 52b downstream of the first chamber heat exchanger, thereby reducing the flow rate of hot water flowing to the evaporator 13 via the chilled water return pipe 45. This reduces the flow rate of hot water to the evaporator 13, lowering the refrigerant pressure in the evaporator 13. As the refrigerant pressure decreases, the temperature of the refrigerant flowing into the compressor also decreases, lowering the temperature of electrical equipment such as the electric motor and inverter.

[0054] When the measured value from the electric motor temperature sensor and / or the measured value from the inverter unit temperature sensor and / or the current value meet a predetermined allowable value, the control unit maintains the refrigerant pressure of the evaporator 13 at a constant value. This ensures that the temperature of the electrical equipment is kept below the allowable value.

[0055] The effects and advantages of this embodiment, as described above, are as follows. In heater mode, if the temperature of the electrical equipment in the compressor 10 rises, the flow rate of hot water to the evaporator 13 is reduced to lower the pressure of the refrigerant circulating in the evaporator 13. This lowers the pressure of the low-pressure refrigerant and reduces the temperature of the refrigerant flowing into the compressor, thereby promoting the cooling of the electrical equipment cooled by the refrigerant. In this way, it is not necessary to reduce the rotational speed of the compressor 10, so the temperature of the electrical equipment in the compressor 10 can be lowered while suppressing a decrease in heating capacity.

[0056] Furthermore, the following controls can be added to this embodiment as an electrical equipment temperature reduction mode. Note that the following controls can also be applied to the first embodiment. <<Rotation speed increase control>> During the de-temperatureing mode for the electrical equipment, rotational speed increase control is performed to increase the rotational speed of the compressor 10. The control unit commands the compressor 10 to increase its rotational speed up to a predetermined number of rotations. The heating capacity in heater mode corresponds to the power (power consumption) of the compressor 10. Here, the compressor power is given by the following relationship: Compressor power = Compressor intake refrigerant density × Compressor rotation speed × Compressor displacement × Enthalpy difference × Efficiency ...(1)

[0057] In equation (1) above, the density of the refrigerant drawn into the compressor 10 decreases due to the de-cooling mode of the electrical equipment. By increasing the rotational speed of the compressor 10 to match the amount corresponding to this decrease in the density of the refrigerant drawn into the compressor, the compressor power can be kept constant. As a result, even when the refrigerant pressure drawn in is reduced in the de-cooling mode of the electrical equipment, the heating capacity (approximately equal to the compressor power) can be maintained.

[0058] Figure 4 shows the relationship between compressor power and compressor speed as described above. In this figure, the horizontal axis represents compressor speed, and the vertical axis represents compressor power. The dashed line represents the case when the suction refrigerant pressure is 0.5 MPa, and the solid line represents the case when the suction refrigerant pressure is 0.3 MPa.

[0059] As a comparative example, as shown by arrow A, if the temperature of the electrical equipment rises in heater mode, controlling the compressor 10 to reduce its rotational speed will decrease the compressor power and reduce the heating capacity.

[0060] In contrast, as indicated by arrow B, when the suction (low-pressure) refrigerant pressure is reduced from 0.5 MPa to 0.3 MPa by the electrical equipment de-temperature mode, the compressor rotation speed can be increased so that the compressor power remains constant. This allows the heating capacity to be maintained.

[0061] The control unit stores the relationship shown in Figure 4 as mathematical formulas and numerical data in its memory unit, and calculates the increase in the rotational speed of the compressor 10 based on the measured suction refrigerant pressure. Based on this calculation result, the control unit controls the inverter unit to drive the electric motor.

[0062] Thus, with rotational speed increase control, even if the power of the compressor 10 decreases due to the reduction in the pressure of the refrigerant flowing through the evaporator 13 (suction refrigerant pressure) in the electrical equipment de-temperatureing mode, the heating capacity can be ensured by increasing the rotational speed of the electric motor that drives the compressor 10 to compensate for the decrease in the power of the compressor 10.

[0063] <<Hot water flow rate increase control>> During the de-temperatureing mode of the electrical equipment, hot water flow rate increase control is performed to increase the flow rate of hot water circulating through the condenser 11. The control unit increases the flow rate of hot water to the condenser 11 by increasing the rotational speed of the hot water pump 30. This increases the amount of heat dissipated in the condenser 11, thereby lowering the high pressure of the refrigerant. As the refrigerant pressure decreases, the temperature of the refrigerant discharged from the compressor also decreases, and the temperature of electrical equipment such as the electric motor and inverter unit decreases.

[0064] When the high-pressure system decreases, the enthalpy difference of the refrigerant decreases, resulting in a decrease in compressor power as shown in equation (1) above. Conversely, by increasing the rotational speed of the compressor 10 to match the amount equivalent to this decrease in enthalpy difference, the compressor power can be kept constant. This makes it possible to maintain heating capacity (approximately equal to the compressor power) even when the high-pressure refrigerant pressure is reduced in the electrical equipment de-temperatureing mode.

[0065] <Example 1> The heater mode shown in Figure 3 can also be achieved by flowing a heat transfer medium, as shown in Figure 5. As shown in Figure 5, the control unit commands the hot water pump 30 to drive the chilled water pump 32 in addition to the chilled water pump 30, causing chilled water to flow through the chilled water discharge pipe 36 and guide it to the upstream three-way valve 52a of the first indoor heat exchanger. At the upstream three-way valve 52a of the first indoor heat exchanger, the hot water and chilled water are mixed and the hot water flows to the first indoor heat exchanger 18. The flow of the hot water that flows out of the first indoor heat exchanger 18 is the same as in Figure 3.

[0066] <Modification 2> The heater mode shown in Figure 3 can also be achieved by flowing a heat transfer medium, as shown in Figure 6. As shown in Figure 6, the control unit commands the hot water pump 30 to stop and the chilled water pump 32 to start. The hot water leaving the condenser 11 passes through the heat transfer medium bypass pipe 47 and merges with the chilled water upstream of the chilled water pump 32. The mixed hot water passes through the chilled water pump 32 and the upstream three-way valve 52a of the first indoor heat exchanger and is led to the first indoor heat exchanger 18. The flow of the hot water flowing out of the first indoor heat exchanger 18 is the same as in Figure 3.

[0067] <Variation 3> The heater mode shown in Figure 3 can be transformed as shown in Figure 7. As shown in Figure 7, an electric heater (heating means) 58 may be provided in the hot water discharge pipe 35 through which hot water flows. Specifically, it is provided downstream of the hot water pump 30 and upstream of the first indoor heat exchanger upstream three-way valve 52a. The electric heater 58 is controlled by the control unit. The control unit activates the electric heater 58 when the heating capacity of the first indoor heat exchanger 18 decreases due to the electrical equipment de-temperature mode. This makes it possible to compensate for the insufficient heating capacity. For example, after increasing the rotational speed of the compressor 10 by the rotational speed increase control described above, if the rotational speed of the compressor 10 reaches the upper limit, it is possible to further compensate for the insufficient heating capacity.

[0068] [Third Embodiment] Next, a third embodiment of this disclosure will be described with reference to Figure 8. The vehicle air conditioning system 1 shown in Figure 8 differs from the second embodiment in the configuration of the refrigerant circuit 3. In the following description, the configurations that differ from the second embodiment will be described, and the same components will be denoted by the same reference numerals and their descriptions will be omitted.

[0069] As shown in Figure 8, the refrigerant circuit 3 is provided with an accumulator 63 between the upstream side (suction side) of the compressor 10 and the evaporator 13. The accumulator 63 separates the refrigerant introduced from the evaporator 13 into gas and liquid, and serves as a container for storing the liquid refrigerant. Note that the accumulator 63 may also be provided in the first or second embodiment.

[0070] The refrigerant circuit 3 is provided with a hot gas bypass passage 60 that bypasses the condenser 11. The hot gas bypass passage 60 connects the compressor 10 and the condenser 11, and the expansion valve 12 and the evaporator 13. The downstream end of the hot gas bypass passage 60 may be provided between the evaporator 13 and the accumulator 63. The hot gas bypass passage 60 is provided with a hot gas bypass valve 61 whose opening degree is controlled by the control unit.

[0071] <Compressor heat source mode> In the vehicle air conditioning system 1 with the above configuration, in the compressor heat source mode, where heating is performed using only the heat source of the compressor 10, the control unit stops the chilled water pump 32 and starts only the hot water pump 30. As a result, only the hot water flowing through the condenser 11 is guided to the first indoor heat exchanger 18 and circulated. On the other hand, chilled water is not circulated through the evaporator 13.

[0072] The control unit opens the hot gas bypass valve 61, allowing some of the hot gas (discharged gas from the compressor 10) to bypass the condenser 11. This adjusts the pressure of the high-pressure refrigerant flowing to the condenser 11 and controls the heating capacity.

[0073] <Electrical equipment temperature reduction mode> In the electrical equipment detemperature reduction mode, the control unit increases the refrigerant flow rate to the condenser 11. Specifically, the control unit reduces the opening of the hot gas bypass valve 61, decreasing the amount of refrigerant flowing through the hot gas bypass channel 60, and relatively increasing the amount of refrigerant flowing through the condenser 11. As a result, more refrigerant flows to the condenser 11, reducing the dryness at the outlet of the evaporator 13 and turning the refrigerant into wet vapor. The wet vapor is separated into gas and liquid by the accumulator 63, and the liquid refrigerant is stored in the accumulator 63. This reduces the amount of refrigerant circulating in the refrigerant circuit 3, thereby lowering the pressure of the refrigerant flowing through the evaporator 13.

[0074] Furthermore, this embodiment can be combined with the rotational speed increase control, hot water flow rate increase control, and electric heater 58 (see Figure 7) described in the second embodiment.

[0075] The temperature control systems and their control methods described in each of the embodiments described above can be understood, for example, as follows.

[0076] A temperature control system according to a first aspect of this disclosure comprises a refrigerant circuit (3) having a compressor (10) for compressing a refrigerant, a high-pressure side heat exchanger (11) for releasing heat from the refrigerant compressed by the compressor, an expansion valve (12) for expanding the refrigerant released heat from the high-pressure side heat exchanger, and a low-pressure side heat exchanger (13) for evaporating the refrigerant expanded by the expansion valve; a heat transfer medium circuit (5) 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 for controlling the refrigerant circuit and the heat transfer medium circuit, wherein the heat transfer medium The circuit comprises a temperature control device (18) that exchanges heat between a heat transfer medium and a temperature-controlled object, and an outdoor heat exchanger (50) that exchanges heat between the heat transfer medium and outside air. The electrical equipment for driving the compressor is cooled by the refrigerant circulating in the refrigerant circuit. The control unit has a compressor heat source mode in which the compressor is used as a heat source to guide the heat transfer medium flowing out of the high-pressure side heat exchanger to the temperature control device to heat the temperature-controlled object, and an electrical equipment de-temperatureing mode in which, in the compressor heat source mode, the pressure of the refrigerant circulating in the low-pressure side heat exchanger is reduced.

[0077] In compressor heat source mode, if the temperature of the compressor's electrical components rises, the pressure of the refrigerant flowing through the low-pressure heat exchanger is reduced. This lowers the pressure of the low-pressure refrigerant, reducing the temperature of the refrigerant flowing into the compressor, thereby promoting the cooling of the electrical components cooled by the refrigerant. In this way, it is not necessary to reduce the compressor's rotational speed, so the temperature of the compressor's electrical components can be reduced while suppressing a decrease in heating capacity. Electrical equipment used to drive the compressor includes, for example, an electric motor that drives the compressor's compression mechanism, and an inverter that controls the rotational speed of the electric motor. The decision of whether or not to activate the cooling mode for electrical equipment is made based, for example, on the temperature of the electrical equipment or the current flowing through it.

[0078] In the first embodiment, the temperature control system according to a second aspect of the present disclosure is configured such that the compressor heat source mode is configured as a heater mode that guides the heat transfer medium discharged from the temperature control equipment to the low-pressure side heat exchanger, and the control unit reduces the flow rate of the heat transfer medium flowing to the low-pressure side heat exchanger or reduces the temperature of the heat transfer medium in the electrical equipment de-temperature mode.

[0079] By reducing the flow rate of the heat transfer medium to the low-pressure heat exchanger, the amount of heat transported from the heat transfer medium after passing through the temperature control equipment is reduced. This allows the pressure of the refrigerant flowing through the low-pressure heat exchanger to be lowered.

[0080] A temperature control system according to a third aspect of the present disclosure, in the first aspect, the refrigerant circuit includes a hot gas bypass passage (60) that bypasses the high-pressure heat exchanger and connects the discharge side of the compressor to the upstream or downstream side of the low-pressure heat exchanger, and the control unit increases the flow rate of refrigerant to the high-pressure heat exchanger in the electrical equipment detemperature mode.

[0081] The heating capacity in the compressor heat source mode is controlled by flowing the refrigerant (hot gas) through the hot gas bypass channel. On the other hand, in the electrical equipment decoupling mode, the refrigerant flow rate to the high-pressure heat exchanger is increased. By increasing the refrigerant flow rate to the high-pressure heat exchanger, the dryness of the refrigerant at the outlet of the low-pressure heat exchanger decreases, turning it into moist vapor. The moist vapor is separated into gas and liquid by the accumulator, and the liquid refrigerant is accumulated in the accumulator. As a result, the amount of refrigerant circulating in the refrigerant circuit decreases, thereby lowering the pressure of the refrigerant flowing through the low-pressure heat exchanger.

[0082] In the fourth aspect of the present disclosure, the temperature control system, in any of the first to third aspects, includes a control unit that increases the rotational speed of the electric motor driving the compressor in the electrical equipment de-temperatureing mode.

[0083] In the de-temperature mode for electrical equipment, the pressure of the refrigerant flowing through the low-pressure heat exchanger is reduced, which decreases the compressor's power. Therefore, the heating capacity can be maintained by increasing the rotational speed of the electric motor that drives the compressor to compensate for the decrease in compressor power. The rotational speed of the electric motor can be increased, for example, until it provides the same compression power as before the pressure of the low-pressure refrigerant was reduced in the de-temperatureing mode for the electrical equipment.

[0084] In the fifth aspect of the present disclosure, the temperature control system, in any of the first to fourth aspects, includes a control unit that, in the electrical equipment de-temperatureing mode, increases the flow rate of the heat transfer medium flowing to the high-pressure side heat exchanger and increases the rotational speed of the electric motor driving the compressor.

[0085] By increasing the flow rate of the heat transfer medium to the high-pressure heat exchanger, the amount of heat dissipated in the high-pressure heat exchanger can be increased, thereby lowering the high pressure of the refrigerant. This reduces the enthalpy difference, which decreases the compressor's power, but the heating capacity can be maintained by increasing the rotational speed of the electric motor.

[0086] A temperature control system according to a sixth aspect of the present disclosure, in any of the first to fifth aspects, includes a heating means (58) for heating a heat transfer medium flowing into the temperature control device, and the control unit activates the heating means when the amount of heating of the temperature control device falls below a predetermined value.

[0087] If the heating level of the temperature control equipment falls below a predetermined value and the heating capacity becomes insufficient, the heating capacity can be maintained by activating the heating means.

[0088] A control method for a temperature control system according to a first aspect of the present disclosure is a control method for a temperature control system comprising: a refrigerant circuit having a compressor for compressing a refrigerant, a high-pressure side heat exchanger for releasing heat from the refrigerant compressed by the compressor, an expansion valve for expanding the refrigerant released heat from the high-pressure side heat exchanger, and a low-pressure side heat exchanger for evaporating the refrigerant expanded by the expansion valve; and a heat medium circuit through which a heat medium that exchanges heat with the refrigerant in the high-pressure side heat exchanger and the low-pressure side heat exchanger circulates, wherein the heat medium circuit is a heat medium The system comprises a temperature control device that exchanges heat between a body and a temperature-controlled object, and an outdoor heat exchanger that exchanges heat between a heat transfer medium and outside air. The electrical equipment for driving the compressor is cooled by the refrigerant circulating in the refrigerant circuit and has a compressor heat source mode in which the compressor is used as a heat source to guide the heat transfer medium flowing out of the high-pressure side heat exchanger to the temperature control device to heat the temperature-controlled object, and an electrical equipment de-temperatureing mode in which, in the compressor heat source mode, the pressure of the refrigerant circulating in the low-pressure side heat exchanger is reduced. [Explanation of symbols]

[0089] 1. Vehicle air conditioning system (temperature control system) 3. Refrigerant Circuit 5 Hot water circuit (heat medium circuit) 7 Chilled water circuit (heat medium circuit) 10 Compressor 11. Condenser (High-pressure side heat exchanger) 12 Expansion valve 13. Evaporator (low-pressure heat exchanger) 18 No. 1 indoor heat exchanger (temperature control equipment) 19 Hot water outlet piping 21 Chilled water outlet piping 22 Second indoor heat exchanger 23. Confluence three-way valve 24. Second Indoor Heat Exchanger Inlet Piping 25 Distribution three-way valve 27. Second Indoor Heat Exchanger Outlet Piping 30 Hot water pump 32. Chilled water pump 35 Hot water discharge piping 36 Cold water discharge piping 41. Piping for the first indoor heat exchanger inlet 42. First Indoor Heat Exchanger Outlet Piping 44 Hot water return piping 45. Chilled water return piping 47 Heat transfer fluid bypass piping 48 Reserve Tank 50 Outdoor heat exchanger 52a Three-way valve upstream of the first chamber heat exchanger 52b First chamber heat exchanger downstream three-way valve 53a Second chamber heat exchanger upstream three-way valve 53b Second chamber heat exchanger downstream three-way valve 56a Outdoor heat exchanger upstream three-way valve 56b Outdoor heat exchanger downstream three-way valve 58 Electric heater (heating means) 60 Hot gas bypass channel 61 Hot gas bypass valve 63 Accumulator

Claims

1. A refrigerant circuit having a compressor for compressing the refrigerant, a high-pressure heat exchanger for releasing heat from the refrigerant compressed by the compressor, an expansion valve for expanding the refrigerant that has released heat from the high-pressure heat exchanger, and a low-pressure heat exchanger for evaporating the refrigerant that has expanded in the expansion valve, A heat transfer medium circuit through which a heat transfer medium circulates in the high-pressure side heat exchanger and the low-pressure side heat exchanger, The system comprises a control unit that controls the refrigerant circuit and the heat transfer medium circuit, The heat transfer circuit comprises a temperature control device that exchanges heat between the heat transfer medium and the temperature to be controlled, and an outdoor heat exchanger that exchanges heat between the heat transfer medium and the outside air. The electrical equipment for driving the compressor is cooled by the refrigerant circulating in the refrigerant circuit. The control unit includes a compressor heat source mode in which the compressor is used as a heat source to guide the heat transfer medium that has flowed out from the high-pressure side heat exchanger to the temperature control equipment to heat the temperature control target, In the compressor heat source mode, there is an electrical equipment temperature reduction mode that reduces the pressure of the refrigerant flowing through the low-pressure side heat exchanger, It has, The aforementioned electrical equipment de-temperatureing mode is a temperature control system that, in the compressor heat source mode, reduces the pressure of the refrigerant flowing through the low-pressure side heat exchanger when the temperature and / or current value of the electrical equipment exceeds a predetermined value.

2. The compressor heat source mode is configured as a heater mode that guides the heat transfer medium discharged from the temperature control equipment to the low-pressure side heat exchanger. The temperature control system according to claim 1, wherein the control unit reduces the flow rate of the heat transfer medium flowing to the low-pressure side heat exchanger or reduces the temperature of the heat transfer medium in the electrical equipment de-temperature mode.

3. The refrigerant circuit includes a hot gas bypass passage that bypasses the high-pressure heat exchanger and connects the discharge side of the compressor to the upstream or downstream side of the low-pressure heat exchanger, Equipped with, The temperature control system according to claim 1, wherein the control unit increases the flow rate of refrigerant to the high-pressure side heat exchanger in the electrical equipment de-temperature mode.

4. The temperature control system according to any one of claims 1 to 3, wherein the control unit increases the rotational speed of the electric motor that drives the compressor in the electrical equipment de-temperature mode.

5. The temperature control system according to any one of claims 1 to 3, wherein the control unit increases the flow rate of the heat transfer medium flowing to the high-pressure side heat exchanger and increases the rotational speed of the electric motor that drives the compressor in the electrical equipment de-temperature mode.

6. The device includes a heating means for heating the heat transfer medium that flows into the temperature control device, The temperature control system according to any one of claims 1 to 3, wherein the control unit activates the heating means when the heating amount of the temperature control device falls below a predetermined value.

7. A refrigerant circuit having a compressor for compressing the refrigerant, a high-pressure heat exchanger for releasing heat from the refrigerant compressed by the compressor, an expansion valve for expanding the refrigerant that has released heat from the high-pressure heat exchanger, and a low-pressure heat exchanger for evaporating the refrigerant that has expanded in the expansion valve, A heat transfer medium circuit through which a heat transfer medium circulates in the high-pressure side heat exchanger and the low-pressure side heat exchanger, A control method for a temperature control system equipped with, The heat transfer circuit comprises a temperature control device that exchanges heat between the heat transfer medium and the temperature to be controlled, and an outdoor heat exchanger that exchanges heat between the heat transfer medium and the outside air. The electrical equipment for driving the compressor is cooled by the refrigerant circulating in the refrigerant circuit. A compressor heat source mode in which the compressor is used as a heat source to guide the heat transfer medium discharged from the high-pressure side heat exchanger to the temperature control equipment to heat the temperature control target, In the compressor heat source mode, there is an electrical equipment temperature reduction mode that reduces the pressure of the refrigerant flowing through the low-pressure side heat exchanger, It has, The aforementioned electrical equipment de-temperatureing mode is a control method for a temperature control system in which, when the temperature and / or current value of the electrical equipment exceeds a predetermined value in the compressor heat source mode, the pressure of the refrigerant flowing through the low-pressure side heat exchanger is reduced.

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