Air conditioning system, vehicle, and control method for the air conditioning system

Abstract

To provide an air conditioner whose heating capacity at the time of rapid heating is high when an outdoor temperature is extremely low, a vehicle, and a control method of the air conditioner.SOLUTION: An air conditioner for executing air conditioning of a target region includes: a compressor for compressing a sucked cooling medium and discharging the compressed cooling medium, a radiator for radiating heat of the cooling medium, an accumulator for accumulating the cooling medium, a first expansion valve provided in a middle of a first flow channel for communicating the compressor with the radiator, a second expansion valve provided in a middle of a second flow channel for communicating the compressor with an upstream side of the accumulator, and a processor configured so as to execute control to close the first expansion valve when starting the compressor, bring the second expansion valve into a predetermined aperture, and open the first expansion valve after elapse of predetermined time.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an air conditioner, a vehicle, and a method for controlling the air conditioner.

Background Art

[0002] Patent Document 1 discloses an air conditioner including a second bypass pipe communicating from the discharge side to the suction side of a compressor, and a decompression device provided in the second bypass pipe. In this air conditioner, at the initial startup of heating, by flowing refrigerant from the compressor to the decompression device of the second bypass pipe, the refrigeration cycle becomes a closed circuit, the pressure of the refrigeration cycle rapidly rises, and the compression work of the compressor rapidly rises. Thereafter, by flowing refrigerant to a decompression device provided in a first bypass pipe communicating with a heat exchanger, the refrigeration cycle is switched to a closed circuit passing through the heat exchanger. At this time, since the compression work of the compressor has already increased, the initial heating capacity of the air conditioner is improved and rapid heating is possible.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technology of Patent Document 1, the heat exchanger is disposed on the low-pressure side of the decompression device, and on the low-pressure side, the refrigerant exchanges heat with sensible heat change in the gas phase region, so the efficiency of heat exchange is poor and the ability to release heat to the air is limited. Furthermore, when switching the refrigeration cycle, the discharge pressure of the compressor decreases and the compression work temporarily decreases, thereby hindering rapid heating.

[0005] Furthermore, in the technology described in Patent Document 1, if refrigerant is flowed only through the second bypass pipe, a highly superheated refrigerant is drawn into the compressor. As a result, when the ambient temperature is extremely low, such as below -20°C, the discharge temperature may rise excessively, making it difficult to continue operation.

[0006] Furthermore, while placing the heat exchanger on the high-pressure side of the pressure reducing device can improve heating capacity, the amount of heat lost is greater than when it is placed on the low-pressure side because high-temperature refrigerant flows into the heat exchanger, and heat loss also occurs upstream of the pressure reducing device. As a result, the discharge pressure of the compressor drops significantly, reducing heating capacity during rapid heating.

[0007] This disclosure has been made in view of the above, and aims to provide an air conditioning system, a vehicle, and a control method for an air conditioning system that have high heating capacity during rapid heating when the outside temperature is extremely low. [Means for solving the problem]

[0008] The air conditioning system according to this disclosure is an air conditioning system that provides air conditioning within a target area, and comprises: a compressor that compresses and discharges an inhaled refrigerant; a heat sink that dissipates heat from the refrigerant; an accumulator that stores the refrigerant; a first expansion valve provided in the middle of a first flow path that connects the compressor and the heat sink; a second expansion valve provided in the middle of a second flow path that connects the compressor and the upstream side of the accumulator; and a processor configured to perform control such as closing the first expansion valve and opening the second expansion valve to a predetermined degree when starting the compressor, and opening the first expansion valve after a predetermined time has elapsed.

[0009] The vehicle according to this disclosure is an air conditioning system for performing air conditioning within a target area, comprising: a compressor that compresses and discharges an inhaled refrigerant; a heat sink that dissipates heat from the refrigerant; an accumulator that stores the refrigerant; a first expansion valve provided in the middle of a first flow path connecting the compressor and the heat sink; a second expansion valve provided in the middle of a second flow path connecting the compressor and the upstream side of the accumulator; and a processor configured to perform control such as closing the first expansion valve and opening the second expansion valve to a predetermined degree when starting the compressor, and opening the first expansion valve after a predetermined time has elapsed.

[0010] The control method for an air conditioning system according to this disclosure comprises a compressor that compresses and discharges an inhaled refrigerant, a heat exchanger that dissipates heat from the refrigerant, an accumulator that stores the refrigerant, a first expansion valve provided in the middle of a first flow path connecting the compressor and the heat exchanger, a second expansion valve provided in the middle of a second flow path connecting the compressor and the upstream side of the accumulator, and a processor that controls the opening and closing of the first and second expansion valves, and is a control method for an air conditioning system that provides air conditioning within a target area, wherein when the processor starts the compressor, it closes the first expansion valve and sets the second expansion valve to a predetermined opening, and after a predetermined time has elapsed, it opens the first expansion valve. [Effects of the Invention]

[0011] According to this disclosure, it is possible to realize an air conditioning system, a vehicle, and a control method for an air conditioning system that have high heating capacity during rapid heating when the outside temperature is extremely low. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a diagram showing the configuration of an air conditioning system according to Embodiment 1. [Figure 2] Figure 2 is a flowchart showing the processes performed by the air conditioning system according to Embodiment 1. [Figure 3] Figure 3 is a pH diagram of the refrigeration cycle. [Figure 4] Figure 4 shows the time evolution of each parameter in the refrigeration cycle. [Figure 5] Figure 5 is a P-h diagram of the refrigeration cycle. [Figure 6] Figure 6 is a P-h diagram of the refrigeration cycle. [Figure 7] Figure 7 is a configuration diagram of the air conditioner according to Embodiment 2. [Figure 8] Figure 8 is a cross-sectional view of the ejector shown in Figure 7. [Figure 9] Figure 9 is a configuration diagram of the air conditioner according to Embodiment 3. [Figure 10] Figure 10 is a cross-sectional view of the accumulator shown in Figure 9. [Figure 11] Figure 11 is a configuration diagram of the air conditioner according to Embodiment 4. [Figure 12] Figure 12 is a configuration diagram of the air conditioner according to Embodiment 5.

Embodiments for Carrying Out the Invention

[0013] The air conditioner, vehicle, and control method of the air conditioner according to the embodiments of the present disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that can be replaced and are easy for those skilled in the art, or those that are substantially the same.

[0014] (Embodiment 1) 〔Configuration of the Air Conditioner〕 Figure 1 is a configuration diagram of the air conditioner according to Embodiment 1. The air conditioner 100 includes a refrigeration cycle 1, a water circuit 5, an HVAC (Heating Ventilation and Air Conditioning) unit 7, and a control unit 10 as a processor. The air conditioner 100 is, for example, an air conditioner for a vehicle that performs air conditioning in a target area, such as the interior of a vehicle. It is mounted on an electric vehicle (BEV: Battery Electric Vehicle) or the like and adjusts the temperature of the air inside the vehicle.

[0015] 〔Configuration of the Refrigeration Cycle〕 The refrigeration cycle 1 is a flow path through which the refrigerant circulates, and includes a compressor 11, a water-cooled medium heat exchanger 12 as a radiator, an indoor heat exchanger 13 as a first heat exchanger, an outdoor heat exchanger 14 as a second heat exchanger, an accumulator 15, and refrigerant pipes connecting these components. The refrigeration cycle 1 also includes first expansion valves 21 to fourth expansion valves 24, a pressure detector 31, and a check valve 32.

[0016] The compressor 11 compresses the refrigerant inhaled from the suction part and discharges it from the discharge part 41. The pipe communicating from the discharge part 41 of the compressor 11 branches into two, one communicating with the water-cooled medium heat exchanger 12 and the other directly communicating with the accumulator 15.

[0017] The water-cooled medium heat exchanger 12 performs heat exchange between the refrigeration cycle 1 and the water circuit 5, and dissipates the heat of the refrigerant. The pipe communicating from the water-cooled medium heat exchanger 12 branches into two, one communicating with the indoor heat exchanger 13 and the other communicating with the outdoor heat exchanger 14.

[0018] The indoor heat exchanger 13 performs heat exchange between the refrigerant and the air in the indoor area, which is the target area.

[0019] The outdoor heat exchanger 14 is arranged in parallel with the indoor heat exchanger 13 between the water-cooled medium heat exchanger 12 and the accumulator 15, and performs heat exchange between the refrigerant and the outdoor air. The outdoor heat exchanger 14 also has a blower fan 140 for discharging air outdoors.

[0020] The accumulator 15 has a function of accumulating the surplus refrigerant in the refrigeration cycle 1, and liquid refrigerant accumulates in the lower part of the internal space of the accumulator 15.

[0021] The first expansion valves 21 to fourth expansion valves 24 are expansion valves having a fully closed function, and their opening degrees can be adjusted under the control of the control unit 10. By changing the combination of the first expansion valves 21 to fourth expansion valves 24 that are fully closed, the flow path through which the refrigerant flows can be switched.

[0022] The first expansion valve 21 is located in the middle of the flow path (first flow path) that connects the discharge section of the compressor 11 and the water-refrigerant heat exchanger 12. The second expansion valve 22 is located in the middle of the bypass flow path (second flow path) that connects the discharge section of the compressor 11 and the upstream side of the accumulator 15. The third expansion valve 23 is located in the middle of the flow path (third flow path) that connects the water-refrigerant heat exchanger 12 and the indoor heat exchanger 13. The fourth expansion valve 24 is located in the middle of the flow path (fifth flow path) that connects the water-refrigerant heat exchanger 12 and the outdoor heat exchanger 14.

[0023] The pressure sensor 31 measures the pressure of the refrigerant discharged from the discharge section 41 of the compressor 11.

[0024] The check valve 32 is installed in the middle of the flow path (sixth flow path) that connects the outdoor heat exchanger 14 and the upstream side of the accumulator 15, and prevents refrigerant from flowing from the accumulator 15 side to the outdoor heat exchanger 14 side.

[0025] [Water circuit configuration] The water circuit 5 is a flow path through which antifreeze circulates, and is also referred to as water in this specification. The water circuit 5 comprises a water pump 51, a water refrigerant heat exchanger 12, an indoor water heat exchanger 52, an outdoor water heat exchanger 53, and water piping connecting these. The water circuit 5 also comprises a three-way valve 54 and a temperature sensor 55.

[0026] The water pump 51 is an electric pump that controls the water flow rate under the control of the control unit 10.

[0027] The water piping connected to the water refrigerant heat exchanger 12 branches into two; one connects to the indoor water heat exchanger 52, and the other connects to the outdoor water heat exchanger 53.

[0028] The indoor water heat exchanger 52 performs heat exchange between water and indoor air. A three-way valve 54 is provided in the water piping that connects to the indoor water heat exchanger 52.

[0029] The outdoor water heat exchanger 53 performs heat exchange between water and the outside. The outdoor water heat exchanger 53 also has a fan 530 that exhausts air to the outside.

[0030] The three-way valve 54 is installed at the branching point of the water piping that communicates with the water refrigerant heat exchanger 12, the indoor water heat exchanger 52, and the outdoor water heat exchanger 53, respectively, and can switch the direction in which water flows.

[0031] The temperature sensor 55 measures the temperature of the water circulating in the water circuit 5.

[0032] [HVAC Unit Configuration] The HVAC unit 7 is a vehicle HVAC unit and includes a blower 71 and a damper 72.

[0033] Blower 71 supplies air for indoor air conditioning.

[0034] The damper 72 regulates the airflow rate through the indoor water heat exchanger 52. By blocking the damper 72, the airflow rate through the indoor water heat exchanger 52 can be reduced to zero.

[0035] [Configuration of the control unit] The control unit 10 is, for example, a vehicle's ECU (Electronic Control Unit) and includes a processor consisting of a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field-Programmable Gate Array), and a memory (main memory unit) consisting of RAM (Random Access Memory), ROM (Read Only Memory), and the like.

[0036] The control unit 10 controls the entire vehicle. Specifically, the control unit 10 acquires the pressure detected by the pressure sensor 31 and the temperature detected by the temperature sensor 55. The control unit 10 also controls the opening degree of the first expansion valve 21 to the fourth expansion valve 24. Furthermore, the control unit 10 controls the operation of the compressor 11, water pump 51, three-way valve 54, blower fan 140, blower fan 530, blower 71, etc.

[0037] [Rapid heating operation] Next, we will describe the processes performed by the air conditioning system 100 during rapid heating operation when the outside temperature is extremely low, such as -20°C or below. In rapid heating operation, the outdoor heat exchanger 14 of the refrigeration cycle 1 does not exchange heat, so the control unit 10 completely closes the fourth expansion valve 24. Similarly, the outdoor water heat exchanger 53 of the water circuit 5 also does not exchange heat, so the control unit 10 controls the three-way valve 54 to connect the water refrigerant heat exchanger 12 and the indoor water heat exchanger 52. In addition, the control unit 10 controls the damper 72 to the position shown in Figure 1, setting the airflow from the blower 71 to pass through the indoor water heat exchanger 52.

[0038] Figure 2 is a flowchart showing the processes performed by the air conditioning system according to Embodiment 1. Figure 2 shows the processes up to the point when the blower 71 starts blowing air into the room.

[0039] First, the control unit 10 fully closes the first expansion valve 21, opens the second expansion valve 22 to a predetermined degree Vo2, opens the third expansion valve 23 to a predetermined degree Vo3, and fully closes the fourth expansion valve 24 (step S1).

[0040] Next, the control unit 10 starts the compressor 11 (step S2). When the compressor 11 is started, the refrigerant circulates from the discharge section 41 of the compressor 11 to the second expansion valve 22, then to the accumulator 15, and finally back to the compressor 11. Since there is no large heat exchanger or other device with large heat capacity or internal volume installed between the compressor 11 and the first and second expansion valves 21 and 22, the heat capacity and internal volume are small. As a result, the rate at which the discharge pressure of the compressor 11 rises can be increased, and the higher the discharge pressure, the greater the compression work of the compressor 11, and the greater the power consumption of the compressor 11.

[0041] The control unit 10 then determines whether the discharge pressure Pd of the compressor 11 is equal to or greater than a predetermined value Pd0 (step S3). The greater the discharge pressure Pd, the greater the compression work of the compressor 11, but the predetermined value Pd0, which is the control target, is determined considering conditions such as the pressure resistance design of the refrigeration cycle 1 and operational constraints. If the control unit 10 determines that the discharge pressure Pd is not equal to or greater than the predetermined value Pd0 (step S3: No), the process in step S3 is repeated. That is, the control unit 10 waits until the discharge pressure Pd becomes equal to or greater than the predetermined value Pd0.

[0042] If the control unit 10 determines that the discharge pressure Pd is equal to or greater than a predetermined value Pd0 (Step S3: Yes), the control unit 10 adjusts the opening degree of the second expansion valve 22 and controls the discharge pressure Pd with a target of the predetermined value Pd0 (Step S4).

[0043] Next, the control unit 10 determines whether the elapsed time t since the compressor 11 was started is greater than a predetermined time t0 (step S5). The predetermined time t0 can be determined by considering the compression work done when the air conditioning system 100 is in operation, the warm-up time for rapid warm-up operation (the time until the blower 71 is started), etc. If the control unit 10 determines that time t is less than or equal to the predetermined time t0 (step S5: No), it returns to step S4 and repeats the process. That is, the control unit 10 continues to execute the process in step S4 until time t becomes greater than the predetermined time t0. During this time, the refrigeration cycle 1 is warmed up by the power of the compressor 11, and a portion of that energy is distributed to the low-pressure side, heating the low-pressure side piping and accumulator 15, etc., that are connected to the suction part of the compressor 11, causing their temperature to rise.

[0044] Figure 3 is a Ph diagram of the refrigeration cycle. Figure 3 is a Ph diagram of refrigeration cycle 1 when steps S3 and S4 are being performed. The refrigerant discharged from the discharge section 41 of the compressor 11 (point B in Figure 3) dissipates heat to the piping etc. on the high-pressure side, causing the enthalpy to decrease (point B → point C). Subsequently, the pressure is reduced by the second expansion valve 22 (point C → point D). Furthermore, heat is dissipated to the piping etc. on the low-pressure side, causing the enthalpy to decrease (point D → point A). Note that due to the presence of the accumulator 15, point A is always located on the saturated vapor line. When the low-pressure side is heated and the temperature rises, the suction pressure of the compressor 11 increases. When the suction pressure increases, the density of the refrigerant drawn in by the compressor 11 also increases, further increasing the compression work of the compressor 11 and increasing power consumption.

[0045] Although the low-pressure side is heated and the suction pressure of the compressor 11 increases, the outdoor heat exchanger 14 remains at a low temperature. Therefore, if the outdoor heat exchanger 14 is connected to the low-pressure side piping, the refrigerant in the low-pressure side piping flows into the outdoor heat exchanger 14 due to an effect similar to that of a heat pipe, and the refrigerant dissipates heat there. To prevent this, a check valve 32 is provided. Because the check valve 32 prevents the refrigerant from flowing into the outdoor heat exchanger 14, heat loss can be reduced, and the suction pressure can be efficiently increased, thereby increasing the power consumption of the compressor 11.

[0046] If the control unit 10 determines that time t is greater than a predetermined time t0 (step S5: Yes), the control unit 10 adjusts the opening degree of the first expansion valve 21 and controls the discharge pressure Pd with a predetermined value Pd0 as the target (step S6). When the first expansion valve 21 is opened, the refrigerant flows in the order of the first expansion valve 21, the water refrigerant heat exchanger 12, the third expansion valve 23, and the indoor heat exchanger 13, merges with the bypass piping via the second expansion valve 22, and is drawn into the compressor 11 via the accumulator 15.

[0047] Figure 4 shows the time variation of each parameter in the refrigeration cycle. Figure 4(a) shows the time variation of the discharge pressure Pd of the compressor 11 and the pressure Pc on the inlet side (first expansion valve 21 side) of the water refrigerant heat exchanger 12. Figures 4(b) to (d) show the time variation of the opening degrees of the first expansion valve 21 to the third expansion valve 23. Figure 4(e) shows the time variation of the water flow rate of the water flowing through the water circuit 5.

[0048] As the suction pressure of the compressor 11 increases over time, the amount of refrigerant discharged from the discharge section 41 of the compressor 11 increases. In order to control the discharge pressure Pd to be near a predetermined value Pd0, the opening degree of the second expansion valve 22 is adjusted when time t ≤ t0, and the opening degree of the second expansion valve 22 is kept constant and the opening degree of the first expansion valve 21 is adjusted when time t > t0. When the opening degree of the first expansion valve 21 increases, the pressure Pc on the inlet side of the water-refrigerant heat exchanger 12 increases.

[0049] In the air conditioning system 100, a first expansion valve 21 and a third expansion valve 23 are provided on the inlet and outlet sides of the water-refrigerant heat exchanger 12, respectively, and the amount of energy used to heat the water-refrigerant heat exchanger 12 can be adjusted by performing two-stage expansion. As a result, even when the first expansion valve 21 is opened, some of the energy is distributed to the heating of the low-pressure side, and heating of the low-pressure side continues, causing the suction pressure of the compressor 11 to rise further and the power consumption to continue to increase.

[0050] Next, the control unit 10 determines whether the opening degree of the first expansion valve 21 is greater than or equal to an opening degree Vo1, which is close to fully open (step S7). If the control unit 10 determines that the opening degree of the first expansion valve 21 is less than the opening degree Vo1 (step S7: No), it returns to step S6 and repeats the process. That is, the control unit 10 continues to execute the process in step S6 until the opening degree of the first expansion valve 21 is greater than or equal to the opening degree Vo1.

[0051] If the control unit 10 determines that the opening degree of the first expansion valve 21 is greater than or equal to opening degree Vo1 (step S7: Yes), the control unit 10 starts the water pump 51 and begins warming up the water circuit 5 (step S8).

[0052] Subsequently, the control unit 10 adjusts the water flow rate of the water circuit 5 by controlling the water pump 51 and controls the discharge pressure Pd with a predetermined value Pd0 as the target (step S9). Alternatively, the control unit 10 may control the amount of heat dissipated to the water by adjusting the continuous flow rate of the water by controlling the output of the water pump 51, as shown in Figure 4(e). In this case, minute flow rate control by the water pump 51 can be avoided, improving the stability of the control and simplifying the control.

[0053] Figure 5 is a Ph diagram of the refrigeration cycle. Figure 5 is a Ph diagram of refrigeration cycle 1 when the processes of steps S9 and S10 are being executed. Of the refrigerant discharged from the discharge section 41 of the compressor 11 (point B in Figure 5), the refrigerant flowing through the bypass channel is depressurized by the second expansion valve 22 and its pressure decreases (point B → point D). On the other hand, the refrigerant flowing through the first expansion valve 21 is not depressurized by the first expansion valve 21 because the first expansion valve 21 is at an opening degree Vo1 that is close to fully open, and heat is transferred from the refrigerant to the water in the water-refrigerant heat exchanger 12, causing the enthalpy to decrease (point B → point E). Furthermore, it is depressurized by the third expansion valve 23 and its pressure decreases (point E → point F). After that, the refrigerant at point F and the refrigerant at point D merge, pass through the accumulator 15, and are drawn into the compressor 11 (point A).

[0054] In the air conditioning system 100, a portion of the refrigerant discharged by the compressor 11 is diverted to a bypass pipe and rejoined on the low-pressure side. As a result, the enthalpy of the refrigerant on the outlet side of the water refrigerant heat exchanger 12 (point E) is smaller than the enthalpy on the suction side of the compressor 11 (point A). Therefore, the region in which the refrigerant is in a gas-liquid two-phase state within the water refrigerant heat exchanger 12 is wider compared to when there is no bypass pipe. The heat transfer mode in the gas-liquid two-phase region is condensation heat transfer, which has a higher heat transfer coefficient than gas-phase heat transfer, and because it is an isothermal change, there is no temperature drop associated with cooling, allowing for higher heat exchange efficiency compared to gas-phase heat transfer. As a result, the water refrigerant heat exchanger 12 in the air conditioning system 100 can be made smaller and have a higher capacity.

[0055] Next, the control unit 10 determines whether the water flow rate Tw detected by the temperature sensor 55 is equal to or greater than a predetermined water flow rate Tw0 (step S10). If the control unit 10 determines that the water flow rate Tw is less than the predetermined water flow rate Tw0 (step S10: No), it returns to step S9 and repeats the process. In other words, the control unit 10 continues to execute the process in step S9 until the water flow rate Tw becomes equal to or greater than the predetermined water flow rate Tw0.

[0056] If the control unit 10 determines that the water flow rate Tw is equal to or greater than a predetermined water flow rate Tw0 (step S10: Yes), the control unit 10 determines that the warm-up of the water circuit 5 is complete and starts blowing air from the blower 71 (step S11).

[0057] In the air conditioning system 100, the refrigerant flows in the order of water refrigerant heat exchanger 12, third expansion valve 23, and indoor heat exchanger 13, and the low-pressure side of the refrigeration cycle 1 is heated and the temperature rises before air is blown from the blower 71. As a result, the temperature of the refrigerant passing through the indoor heat exchanger 13 is higher than the temperature of the air at the start of airflow.

[0058] Figure 6 is a pH diagram of the refrigeration cycle. Figure 6 is a pH diagram of refrigeration cycle 1 after the start of air supply from the blower 71 in step S11. The refrigerant, which has been depressurized by the third expansion valve 23 (point F in Figure 6), is cooled in the indoor heat exchanger 13 by air at a temperature lower than the saturation temperature of the refrigerant, causing a decrease in enthalpy (point F → point G).

[0059] In the air conditioning system 100, air heating is performed not only by the indoor water heat exchanger 52 but also by the indoor heat exchanger 13, which allows for a greater maximum heating capacity compared to a configuration using only an indoor water heat exchanger 52 of the same size. Furthermore, by performing air heating with both the indoor water heat exchanger 52 and the indoor heat exchanger 13 in the air conditioning system 100, the indoor water heat exchanger 52 can be made smaller compared to a configuration with the same maximum heating capacity where the air is heated only by the indoor water heat exchanger 52.

[0060] According to Embodiment 1 described above, when the compressor 11 is started, the control unit 10 closes the first expansion valve 21 and sets the second expansion valve 22 to a predetermined opening degree Vo2, and after a predetermined time t0 has elapsed, it controls the opening of the first expansion valve 21. As a result, by reducing the heat capacity and internal volume of the space between the discharge section 41 of the compressor 11 and the first and second expansion valves 21 and 22, the rate at which the discharge pressure rises when the compressor 11 is started can be increased, and the rate at which the power consumption of the compressor 11 rises can be improved. When the power consumption of the compressor 11 increases, the amount of work done by the compressor 11 increases, and the heating capacity during rapid heating can be improved.

[0061] Furthermore, the control unit 10 expands the refrigerant in two stages by adjusting the opening of the first expansion valve 21 and the opening of the third expansion valve 23, thereby controlling the pressure inside the water-refrigerant heat exchanger 12 to be above the suction pressure and below the discharge pressure of the compressor 11. By expanding the refrigerant in two stages, the amount of heat released to the water-refrigerant heat exchanger 12 can be controlled, ensuring that energy is available for heating on the low-pressure side, and thus increasing the power consumption of the compressor 11.

[0062] Furthermore, after a predetermined time t0 has elapsed, the control unit 10 adjusts the opening degree of the first expansion valve 21 based on a target value (predetermined value Pd0) of the discharge pressure Pd of the compressor 11. As a result, the pressure Pc on the inlet side of the water refrigerant heat exchanger 12 can be gradually increased without lowering the discharge pressure Pd of the compressor 11.

[0063] Next, we will explain the operating methods of the air conditioning unit 100 other than rapid heating operation.

[0064] [Cooling operation] The control unit 10 fully opens the first expansion valve 21, fully closes the second expansion valve 22 and the fourth expansion valve 24, and controls the opening degree of the third expansion valve 23 to adjust the room temperature. The control unit 10 also sets the three-way valve 54 to allow water to flow from the water refrigerant heat exchanger 12 to the outdoor water heat exchanger 53.

[0065] The refrigerant discharged from the discharge section 41 of the compressor 11 dissipates heat to the water circuit 5 in the water refrigerant heat exchanger 12, is depressurized in the third expansion valve 23, and evaporates in the indoor heat exchanger 13 to cool the indoor air. In the water circuit 5, the water is heated in the water refrigerant heat exchanger 12 and cooled in the outdoor water heat exchanger 53.

[0066] [Heating operation] The control unit 10 fully opens the first expansion valve 21, fully closes the second and third expansion valves 22 and 23, and controls the opening degree of the fourth expansion valve 24 to adjust the room temperature. The control unit 10 also sets the three-way valve 54 to allow water to flow from the water refrigerant heat exchanger 12 to the indoor water heat exchanger 52.

[0067] The refrigerant discharged from the discharge section 41 of the compressor 11 dissipates heat to the water circuit 5 in the water refrigerant heat exchanger 12, is depressurized in the fourth expansion valve 24, and evaporates in the outdoor heat exchanger 14, absorbing heat from the air. In the water circuit 5, the water is heated in the water refrigerant heat exchanger 12, and the indoor air is warmed in the indoor water heat exchanger 52.

[0068] [Dehumidification operation] The control unit 10 fully opens the first expansion valve 21, fully closes the second expansion valve 22 and the fourth expansion valve 24, and controls the opening degree of the third expansion valve 23 to adjust the room temperature. The control unit 10 also controls the three-way valve 54 to set the flow of water from the water refrigerant heat exchanger 12 to the indoor water heat exchanger 52.

[0069] The refrigerant discharged from the discharge section 41 of the compressor 11 dissipates heat to the water circuit 5 in the water refrigerant heat exchanger 12, is depressurized in the third expansion valve 23, and evaporates in the indoor heat exchanger 13 to dehumidify the indoor air. In the water circuit 5, the water is heated in the water refrigerant heat exchanger 12, and the dehumidified air is warmed in the indoor water heat exchanger 52.

[0070] (Embodiment 2) Figure 7 is a diagram showing the configuration of the air conditioning system according to Embodiment 2. Components similar to those in Embodiment 1 are denoted by the same reference numerals as in Figure 1, and their descriptions are omitted as appropriate.

[0071] The refrigeration cycle 1A of the air conditioning unit 100A is provided at the connection point between a bypass passage (second passage) that connects the discharge section 41 of the compressor 11 and the upstream side of the accumulator 15, and a passage (fourth passage) that connects the liquid reservoir of the accumulator 15 and the second expansion valve 22. It includes an ejector 81 that sucks up the liquid refrigerant accumulated in the liquid reservoir of the accumulator 15 and mixes it with the refrigerant that has passed through the second expansion valve 22, and a throttle 82 that adjusts the amount of refrigerant sucked up by the ejector 81.

[0072] Figure 8 is a cross-sectional view of the ejector shown in Figure 7. As shown in Figure 8, the ejector 81 consists of three parts: a nozzle 810, a body 811, and an inlet 812. These three parts are made of a metal such as aluminum or stainless steel.

[0073] The nozzle 810 is fitted into the body 811, with its upper end pressed against the inlet 812. The body 811 and the inlet 812 are then joined by welding or brazing, fixing the nozzle 810 inside the body 811.

[0074] The piping that communicates with the second expansion valve 22 is connected to the inlet 813, the piping that communicates with the accumulator 15 is connected to the outlet 814, and the piping that communicates with the liquid reservoir of the accumulator 15 is connected to the suction port 815.

[0075] The outlet portion 8101 of the nozzle 810 has a smaller cross-sectional area of ​​the flow path compared to the inlet 813 through which the refrigerant from the second expansion valve 22 flows in, causing the refrigerant to increase in velocity as it passes through the nozzle 810. According to the law of conservation of energy, as the flow velocity increases, the pressure decreases. Therefore, the pressure in the space 817 becomes lower than the pressure inside the accumulator 15, and this negative pressure is used to draw in the liquid refrigerant stored in the accumulator 15. The flow rate of the refrigerant drawn from the reservoir portion of the accumulator 15 to the ejector 81 can be adjusted by the opening of the throttle 82. The drawn-in liquid refrigerant is mixed with the refrigerant from the second expansion valve 22 in the mixing section 816. Heat exchange occurs by mixing the liquid refrigerant with the refrigerant from the second expansion valve 22. The cross-sectional area of ​​the flow path in the mixing section 816 and downstream thereof is larger than the cross-sectional area of ​​the flow path at the outlet portion 8101 of the nozzle 810, so the flow velocity decreases and the pressure increases.

[0076] In a configuration without an ejector 81, if the first expansion valve 21 is fully closed and the second expansion valve 22 is opened, allowing refrigerant to flow through the bypass piping, high-temperature refrigerant will flow into the accumulator 15. The accumulator 15 is configured to store excess refrigerant by separating the incoming refrigerant into gas and liquid phases and storing the liquid phase at the bottom of the accumulator 15. When high-temperature gaseous refrigerant flows into the accumulator 15, it passes through the space at the top of the accumulator 15, but at this time, it may not exchange heat sufficiently with the liquid refrigerant stored at the bottom. In this case, even if liquid refrigerant is stored in the accumulator 15, the incoming high-temperature refrigerant will flow out of the accumulator 15 and be drawn into the compressor 11. If the refrigerant drawn into the compressor 11 is overheated, the temperature of the refrigerant discharged from the compressor 11 will rise. The compressor 11 has a set upper limit on the temperature of the discharged refrigerant for protection, and if the temperature of the discharged refrigerant rises, the operating time of the compressor 11 may be shortened. In addition, the system is configured to increase the power consumption of the compressor 11 by opening the second expansion valve 22 and flowing high-temperature refrigerant through the bypass piping, thereby heating the low-pressure side and increasing the suction pressure of the compressor 11. However, because the overheated refrigerant is drawn into the compressor 11 and used to heat the compressor 11, the amount of heat available for heating the low-pressure side decreases, and the increase in the power consumption of the compressor 11 is hindered.

[0077] In contrast, in the air conditioning unit 100A, the ejector 81 mixes the refrigerant that has passed through the second expansion valve 22 with the liquid refrigerant stored in the reservoir of the accumulator 15 and flows it into the accumulator 15. As a result, the refrigerant that has passed through the second expansion valve 22 passes through the accumulator 15, preventing it from being drawn into the compressor 11 while still at a high temperature, preventing the refrigerant discharged from the discharge section 41 of the compressor 11 from becoming overheated, and increasing the energy used for heating on the low-pressure side.

[0078] Furthermore, since the ejector 81 draws in the liquid refrigerant accumulated in the reservoir of the accumulator 15, it can pump the liquid refrigerant by utilizing the energy of the refrigerant's expansion, thus achieving a pumping action without using excess energy.

[0079] (Embodiment 3) Figure 9 is a diagram showing the configuration of the air conditioning system according to Embodiment 3. Components similar to those in Embodiment 1 are denoted by the same reference numerals as in Figure 1, and their descriptions are omitted as appropriate.

[0080] The refrigeration cycle 1B of the air conditioning unit 100B is equipped with an accumulator 15B. The piping that communicates with the second expansion valve 22 is connected to the lower part of the accumulator 15B.

[0081] Figure 10 is a cross-sectional view of the accumulator shown in Figure 9. As shown in Figure 10, the accumulator 15B includes an accumulator tank 151 for storing liquid refrigerant, an inlet 152 connected to the low-pressure side piping, an outlet pipe 153 connected to the suction side of the compressor 11, and a pipe 154 having an inner diameter larger than the outer diameter of the outlet pipe 153, with one end (lower end) closed, and arranged coaxially with the outlet pipe 153.

[0082] A return hole 155 is formed on the lower side of the pipe 154, and a cylindrical filter 156 is attached to the outer circumference of the hole 155 to prevent foreign matter from clogging it. The umbrella portion 157 separates the space 158 into which the refrigerant flows in from the lower space 159 into which the liquid refrigerant is stored. The bypass flow channel pipe 160 is connected to a bypass flow channel that communicates with the second expansion valve 22. A liquid injection hole 161 is formed on the lower side of the bypass flow channel pipe 160. The bypass flow channel pipe 160 communicates with the space 158 above the umbrella portion 157, and the refrigerant that has passed through the bypass flow channel flows into the space 158.

[0083] The refrigerant flowing into the space 158 from the inlet 152 passes through the gap 1570 on the outer circumference of the umbrella portion 157 and flows into the lower space 159. In the lower space 159, the refrigerant is separated into gas and liquid phases by gravity, and the liquid refrigerant accumulates at the bottom of the accumulator 15. At the same time, the gas phase refrigerant passes through the opening at the upper end of the pipe 154, between the pipe 154 and the outlet pipe 153, and liquid refrigerant with dissolved oil flows in through the hole 155. The refrigerant flowing through the pipe 154 and the liquid refrigerant flowing in through the hole 155 are mixed and flow out through the internal space of the outlet pipe 153.

[0084] Liquid refrigerant is injected into the bypass flow channel pipe 160 through the liquid injection hole 161 due to the pressure of the stored liquid refrigerant. The refrigerant from the second expansion valve 22 and the liquid refrigerant injected from the liquid injection hole 161 mix and flow out into the upper space 158 of the umbrella portion 157. Furthermore, it flows through the gap 1570 on the outer circumference of the umbrella portion 157 and into the lower space 159. There, it undergoes gas-liquid separation in the same way as the refrigerant from the inlet 152, with the liquid refrigerant accumulating at the bottom of the accumulator 15 and the gaseous refrigerant flowing out.

[0085] According to Embodiment 3, the same effect as the ejector 81 in Embodiment 2 can be obtained by using the pressure due to gravity acting on the liquid refrigerant stored at the bottom of the accumulator 15 to push the liquid refrigerant into the refrigerant from the bypass piping. Furthermore, in Embodiment 3, it is not necessary to provide piping that connects the liquid storage section of the accumulator 15 to the second expansion valve 22, as in Embodiment 2, thus simplifying the configuration compared to Embodiment 2.

[0086] (Embodiment 4) Figure 11 is a configuration diagram of the air conditioning system according to Embodiment 4. As shown in Figure 11, the refrigeration cycle 1C of the air conditioning system 100C is equipped with an indoor radiator 121, while the water circuit 5C is not equipped with an indoor radiator. In the configuration shown in Figure 1, where the water circuit 5 is equipped with an indoor radiator and heating operation is performed using the heat of the water circuit, it takes time from the start of the compressor 11 until the blower 71 is turned on due to the heat capacity of the water. In contrast, in Embodiment 4, since warming up the water circuit 5 is unnecessary, the start-up time until heating operation can be shortened.

[0087] The refrigeration cycle 1C includes an indoor radiator 121 installed in a piping branched from the refrigerant discharged from the compressor 11. Furthermore, the refrigeration cycle 1C includes a first expansion valve B211 installed on the inlet side of the indoor radiator 121 and a check valve 321 installed on the outlet side. In addition, the refrigeration cycle 1C includes a first expansion valve A210 installed on the inlet side of the water refrigerant heat exchanger 12 and a check valve 320 installed on the outlet side.

[0088] [Rapid heating operation] In rapid heating operation at extremely low temperatures such as -20°C, the control unit 10 prevents refrigerant from flowing into the water-refrigerant heat exchanger 12 by keeping the first expansion valve A210 completely closed at all times. In addition, a check valve 320 is provided on the outlet side of the water-refrigerant heat exchanger 12, so refrigerant is also prevented from flowing in from the outlet side. The control unit 10 controls the first expansion valve B211 in the same way as the first expansion valve 21 in Embodiment 1.

[0089] When the control unit 10 starts the compressor 11 with the first expansion valve B211 fully closed, the refrigerant flows to the suction side of the accumulator 15 via the second expansion valve 22. After the discharge pressure Pd of the compressor 11 reaches a predetermined value Pd0 or higher, and the elapsed time t reaches a predetermined time t0, the control unit 10 opens the first expansion valve B211 to allow refrigerant to flow to the indoor radiator 121 side as well. The refrigerant flowing on the indoor radiator 121 side flows in the order of first expansion valve B211, indoor radiator 121, check valve 321, third expansion valve 23, and indoor heat exchanger 13, and merges with the refrigerant on the bypass piping side that has passed through the second expansion valve 22 in the low-pressure piping, and is drawn into the compressor 11 via the accumulator 15. The control unit 10 adjusts the opening degree of the first expansion valve B211 so that the discharge pressure Pd of the compressor 11 becomes a predetermined value Pd0. As the opening of the first expansion valve B211 increases, the pressure inside the indoor radiator 121 rises. When the opening of the first expansion valve B211 reaches an opening of Vo1 or greater, which is close to fully open, the control unit 10 starts the blower 71 to heat the indoor air and begin heating.

[0090] Next, we will explain the operating methods of the air conditioning unit 100C other than rapid heating operation.

[0091] [Cooling operation] The control unit 10 fully opens the first expansion valve A210, fully closes the first expansion valve B211, fully closes the second expansion valve 22, controls the opening degree of the third expansion valve 23 to adjust the room temperature, and fully closes the fourth expansion valve.

[0092] The refrigerant discharged from the discharge port 41 of the compressor 11 is released into the water circuit 5C via the water refrigerant heat exchanger 12, depressurized by the third expansion valve 23, and then evaporates in the indoor heat exchanger 13 to cool the air. In the water circuit 5C, the water is heated in the water refrigerant heat exchanger 12 and cooled in the outdoor water heat exchanger 53.

[0093] [Heating operation] The control unit 10 adjusts the room temperature by fully closing the first expansion valve A210, fully opening the first expansion valve B211, fully closing the second expansion valve 22, fully closing the third expansion valve 23, and controlling the opening degree of the fourth expansion valve 24.

[0094] The refrigerant discharged from the discharge port 41 of the compressor 11 heats the indoor air in the indoor radiator 121. Subsequently, the refrigerant is depressurized in the fourth expansion valve 24, and in the outdoor heat exchanger 14, the refrigerant evaporates and absorbs heat from the air.

[0095] [Dehumidification operation (1)] The control unit 10 fully closes the first expansion valve A210, fully opens the first expansion valve B211, fully closes the second expansion valve 22, adjusts the opening degree of the third expansion valve 23 to adjust the room temperature, and fully closes the fourth expansion valve 24.

[0096] The refrigerant discharged from the discharge port 41 of the compressor 11 heats the cabin air in the cabin radiator 121, is depressurized in the third expansion valve 23, and evaporates in the cabin heat exchanger 13, thus dehumidifying the cabin.

[0097] [Dehumidification operation (2)] Dehumidification mode (2) is an operating mode that increases the amount of heat released to the outside air compared to dehumidification mode (1), thereby suppressing the temperature rise of the dehumidified air.

[0098] The control unit 10 opens the first expansion valve A210 and the first expansion valve B211, and the refrigerant flows in parallel through the water refrigerant heat exchanger 12 and the indoor radiator 121. In the water refrigerant heat exchanger 12, heat is released to the water circuit 5C, and in the indoor radiator 121, the indoor air is heated. The amount of heat released to the water can be adjusted by adjusting the water flow rate of the water circuit 5C with the water pump 51. If the amount of heat released to the water is small, it may be difficult to adjust the water flow rate with the water pump 51, in which case the water pump 51 may be switched on or off. The refrigerant from the water refrigerant heat exchanger 12 and the refrigerant from the indoor radiator 121 merge, are depressurized by the third expansion valve 23, and the refrigerant evaporates in the indoor heat exchanger 13 to dehumidify.

[0099] (Embodiment 5) Figure 12 is a diagram showing the configuration of an air conditioning system according to Embodiment 5. As shown in Figure 12, the battery temperature control water circuit 9 of the air conditioning system 100D includes a second water pump 91, a second water refrigerant heat exchanger 92, a second outdoor water heat exchanger 93, a second three-way valve 94, and a battery heat exchanger 95 that exchanges heat with the battery 950.

[0100] The second water pump 91 is an electric pump that controls the water flow rate under the control of the control unit 10.

[0101] The second water-refrigerant heat exchanger 92 performs heat exchange between the water circulating in the battery temperature control water circuit 9 and the refrigerant circulating in the refrigeration cycle 1.

[0102] The second outdoor water heat exchanger 93 performs heat exchange between water and the outside. The second outdoor water heat exchanger 93 also has a fan 930 for exhausting air to the outside.

[0103] The second three-way valve 94 is installed at the branching point of the water piping that connects to the second water pump 91, the second outdoor water heat exchanger 93, and the battery heat exchanger 95, respectively, and can switch the direction in which water flows.

[0104] The battery heat exchanger 95 performs heat exchange between the water circulating in the battery temperature control water circuit 9 and the battery 950.

[0105] When the control unit 10 performs battery temperature control, it sets the second three-way valve 94 to a path in which water flows in the order of second water pump 91, battery heat exchanger 95, second water refrigerant heat exchanger 92, and second water pump 91, and performs heat exchange between the battery 950 and the refrigeration cycle 1.

[0106] When the control unit 10 performs heating by absorbing heat from the outside air using a heat pump, it sets the second three-way valve 94 to a path in which water flows in the following order: second water pump 91, second outdoor water heat exchanger 93, second water refrigerant heat exchanger 92, and second water pump 91.

[0107] In addition, when the battery temperature control system heats the battery 950 using the heat from the refrigeration cycle 1, a bypass pipe equipped with a second expansion valve 22 is connected to the inlet side of the second water refrigerant heat exchanger 92 in order to flow the high-temperature refrigerant discharged from the discharge section 41 of the compressor 11 to the second water refrigerant heat exchanger 92.

[0108] [Rapid heating operation] In rapid heating operation at extremely low temperatures such as -20°C, the control unit 10 performs the same control as in Embodiment 1. When the control unit 10 starts the compressor 11, the refrigerant flows in the order of the second expansion valve 22, the second water-refrigerant heat exchanger 92, and the accumulator 15, and is drawn into the compressor 11. However, in order to suppress heat dissipation in the second water-refrigerant heat exchanger 92, the control unit 10 stops the second water pump 91.

[0109] In the mode for heating the battery, the control unit 10 fully closes the first expansion valve 21, adjusts the opening of the second expansion valve 22, fully closes the third expansion valve 23, and fully closes the fourth expansion valve 24. The refrigerant discharged from the discharge section 41 of the compressor 11 is depressurized in the second expansion valve 22, exchanges heat with the water in the battery temperature control water circuit 9 in the second water-refrigerant heat exchanger 92, and is drawn into the compressor 11 via the accumulator 15. This is a so-called hot gas cycle, in which the water circulating in the battery temperature control water circuit 9 is heated by the high-temperature refrigerant. The water circulation path in the battery temperature control water circuit 9 is in the order of second water pump 91, second three-way valve 94, battery heat exchanger 95, second water-refrigerant heat exchanger 92, and second water pump 91, and the water heated in the second water-refrigerant heat exchanger 92 heats the battery 950.

[0110] According to Embodiment 5, the bypass piping and the second expansion valve 22, which are provided for rapid heating operation when the outside temperature is extremely low, can also be used for temperature control of the battery 950.

[0111] Next, we will explain the operating methods of the air conditioning unit 100D other than rapid heating operation.

[0112] [Cooling operation] The control unit 10 fully opens the first expansion valve 21, fully closes the second expansion valve 22, adjusts the opening degree of the third expansion valve 23 to adjust the room temperature, and fully closes the fourth expansion valve 24.

[0113] The refrigerant discharged from the discharge port 41 of the compressor 11 dissipates heat into water in the water refrigerant heat exchanger 12, is depressurized in the third expansion valve 23, and evaporates in the indoor heat exchanger 13 to cool the air. In the water circuit 5, water is heated in the water refrigerant heat exchanger 12 and cooled in the outdoor water heat exchanger 53.

[0114] [Heating operation] The control unit 10 adjusts the room temperature by fully opening the first expansion valve 21, fully closing the second expansion valve 22, fully closing the third expansion valve 23, and controlling the opening degree of the fourth expansion valve 24.

[0115] The refrigerant discharged from the discharge section 41 of the compressor 11 heats the water in the water circuit 5 in the water refrigerant heat exchanger 12, is depressurized in the fourth expansion valve 24, and the refrigerant evaporates in the second water refrigerant heat exchanger 92, absorbing heat from the water in the battery temperature control water circuit 9.

[0116] In the water circuit 5, the control unit 10 controls the three-way valve 54 to cause water to flow in the following order: water pump 51, water-refrigerant heat exchanger 12, three-way valve 54, indoor water heat exchanger 52, and water pump 51. The water heated in the water-refrigerant heat exchanger 12 then releases heat to the air in the indoor water heat exchanger 52, providing heating.

[0117] In the battery temperature control water circuit 9, the control unit 10 controls the second three-way valve 94 to cause water to flow in the following order: second water pump 91, second three-way valve 94, second outdoor water heat exchanger 93, second water refrigerant heat exchanger 92, and second water pump 91. In the second outdoor water heat exchanger 93, the water absorbs heat from the outside air, and in the second water refrigerant heat exchanger 92, the water heats the refrigerant.

[0118] [Dehumidification operation] The control unit 10 adjusts the room temperature by fully opening the first expansion valve 21, fully closing the second expansion valve 22, and controlling the opening degree of the third expansion valve 23, and fully closing the fourth expansion valve. The control unit 10 sets the three-way valve 54 so that water flows in the order of the water refrigerant heat exchanger 12 and the indoor water heat exchanger 52.

[0119] The refrigerant discharged from the discharge port 41 of the compressor 11 dissipates heat into water in the water refrigerant heat exchanger 12, is depressurized in the third expansion valve 23, and evaporates in the indoor heat exchanger 13, dehumidifying the air. In the water circuit 5, water is heated in the water refrigerant heat exchanger 12, and the dehumidified air is warmed in the indoor water heat exchanger 52.

[0120] [Battery cooling operation] The control unit 10 controls the opening of the first expansion valve 21 to the fullest, the second expansion valve 22 to the fullest, the third expansion valve 23 to the fullest, and the opening degree of the fourth expansion valve 24.

[0121] The refrigerant discharged from the discharge section 41 of the compressor 11 dissipates heat into water in the water-refrigerant heat exchanger 12, is depressurized in the fourth expansion valve 24, and the refrigerant evaporates in the second water-refrigerant heat exchanger 92 to cool the water circulating in the battery temperature control water circuit 9. In the battery temperature control water circuit 9, the control unit 10 controls the second three-way valve 94 to cause water to flow in the order of second water pump 91, second three-way valve 94, battery heat exchanger 95, second water-refrigerant heat exchanger 92, and second water pump 91, and the water cooled in the second water-refrigerant heat exchanger 92 cools the battery 950.

[0122] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of Symbols]

[0123] 1, 1A, 1B, 1C Refrigeration Cycle 5, 5C water circuit 7 HVAC Units 9 Water circuit for battery temperature control 10 Control Unit 11 Compressor 12 Water refrigerant heat exchanger 13 Indoor heat exchanger 14 Outdoor heat exchanger 15, 15B Accumulator 21. First expansion valve 22. Second expansion valve 23 Third expansion valve 24. Fourth expansion valve 31. Pressure detector 32 Check valve 41 Discharge part 51 Water pump 52 Indoor water heat exchanger 53 Outdoor water heat exchanger 54 Three-way valve 55 Temperature detector 71 Blower 72 dampers 81 Ejector 82 aperture 91. Second water pump 92 Second water refrigerant heat exchanger 93 2nd outdoor water heat exchanger 94 Second three-way valve 95 Battery heat exchanger 100, 100A, 100B, 100C, 100D air conditioner 121 Indoor radiator 140 Blower fan 151 Accumulator Tank 152 Inlet 153 Outflow pipe 154 tube 155 holes 156 filters 157 Umbrella section 158 Space 159 Lower space 160 Bypass channel pipe 161 Liquid injection hole 320 Check valve 321 Check valve 530 Blower fan 810 Nozzles 811 Body 812 Inlet 813 Inlet 814 Outlet 815 Inlet 816 Mixing section 817 Space 930 Blower fan 950 battery 1570 Gap 8101 Exit section A210 First Expansion Valve B211 First Expansion Valve

Claims

1. An air conditioning system that provides air conditioning within a target area, A compressor that compresses and discharges the refrigerant it has drawn in, A heat sink for dissipating the heat of the aforementioned refrigerant, An accumulator for storing the aforementioned refrigerant, A first expansion valve is provided in the middle of the first flow path that connects the compressor and the heat sink, A second expansion valve is provided in the middle of a second flow path that connects the compressor and the upstream side of the accumulator, A processor that, when starting the compressor, closes the first expansion valve and sets the second expansion valve to a predetermined opening, and after a predetermined time has elapsed, opens the first expansion valve while maintaining the opening of the second expansion valve at a constant level. An air conditioning system equipped with the following features.

2. A first heat exchanger that performs heat exchange between the refrigerant and the air within the target region, A third expansion valve is provided in the middle of a third flow path that connects the heat sink and the first heat exchanger, Equipped with, The aforementioned processor, The air conditioning device according to claim 1, wherein the refrigerant is expanded in two stages by adjusting the opening degree of the first expansion valve and the opening degree of the third expansion valve, and the pressure inside the heat exchanger is controlled to be between the suction pressure and the discharge pressure of the compressor.

3. The air conditioning device according to claim 1, wherein a fourth flow path is provided that connects the liquid storage section of the accumulator with the downstream side of the second expansion valve of the second flow path, and the refrigerant that has passed through the second expansion valve is mixed with the liquid refrigerant accumulated in the liquid storage section and flows into the accumulator.

4. The air conditioning device according to claim 3, further comprising an ejector provided at the connection between the second flow path and the fourth flow path, which sucks in the liquid refrigerant accumulated in the liquid storage section and mixes it with the refrigerant that has passed through the second expansion valve.

5. The aforementioned processor, The air conditioning device according to claim 2, wherein the refrigerant is flowed in series between the heat radiator and the first heat exchanger.

6. A first heat exchanger that performs heat exchange between the refrigerant and the air within the target region, A second heat exchanger is positioned in parallel with the first heat exchanger between the heat sink and the accumulator, and performs heat exchange between the refrigerant and the air outside the target area. A fourth expansion valve is provided in the middle of a fifth flow path that connects the heat sink and the second heat exchanger, A check valve is provided in the middle of a sixth flow path that connects the second heat exchanger and the upstream side of the accumulator, An air conditioning device according to claim 1, comprising:

7. The air conditioning device according to claim 1, wherein the processor adjusts the opening degree of the first expansion valve based on a target value of the discharge pressure of the compressor after the predetermined time has elapsed.

8. An air conditioning system that provides air conditioning within a target area, A compressor that compresses and discharges the refrigerant it has drawn in, A heat sink for dissipating the heat of the aforementioned refrigerant, An accumulator for storing the aforementioned refrigerant, A first expansion valve is provided in the middle of the first flow path that connects the compressor and the heat sink, A second expansion valve is provided in the middle of a second flow path that connects the compressor and the upstream side of the accumulator, A processor configured to perform control such that, when starting the compressor, it closes the first expansion valve and sets the second expansion valve to a predetermined opening, and after a predetermined time has elapsed, opens the first expansion valve while maintaining the opening of the second expansion valve at a constant level, A vehicle equipped with the following features.

9. A compressor that compresses and discharges the refrigerant it has drawn in, A heat sink for dissipating the heat of the aforementioned refrigerant, An accumulator for storing the aforementioned refrigerant, A first expansion valve is provided in the middle of the first flow path that connects the compressor and the heat sink, A second expansion valve is provided in the middle of a second flow path that connects the compressor and the upstream side of the accumulator, A processor that controls the opening and closing of the first and second expansion valves, A control method for an air conditioning system that provides air conditioning within a target area, comprising: The aforementioned processor, When starting the compressor, the first expansion valve is closed and the second expansion valve is opened to a predetermined degree. After a predetermined time has elapsed, the first expansion valve is opened while maintaining the opening degree of the second expansion valve at a constant level. A method for controlling an air conditioning system.

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