Heat-accumulation air-conditioning system and control method

Abstract

To provide a heat-accumulation type air-conditioning system capable of reducing power consumption required for air conditioning.SOLUTION: A heat-accumulation air-conditioning system includes: a compressor that compresses a refrigerant; a condenser that condenses the refrigerant compressed by the compressor; a heat exchanger for heat accumulation that is provided on a downstream side of the condenser; an expansion valve that is provided on a downstream side of the heat exchanger for heat accumulation; an evaporator that evaporates the refrigerant decompressed by the expansion valve; a main pipeline that connects the compressor, the condenser, the heat exchanger for heat accumulation, the expansion valve, and the evaporator, and through which the refrigerant passes; a heat accumulation tank that stores a heat accumulation material; a pump that sends the heat accumulation material to the heat exchanger for heat accumulation; and a heat accumulation material flow path that connects the heat accumulation tank, the pump, and the heat exchanger for heat accumulation, and through which the heat accumulation material passes.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a heat storage air conditioning system and a control method.

Background Art

[0002] Patent Document 1 discloses an air conditioning system for a subway vehicle, which includes a heat source tank that accommodates a coolant source in a supply and dischargeable manner, and an indoor unit that cools the interior of the vehicle by heat exchange using the coolant source in the heat source tank. The air conditioning system also includes an air conditioning device that circulates the coolant source between the heat source tank and the indoor unit, and a heat source supply and discharge device that exchanges the coolant source in the heat source tank heated by heat exchange in the indoor unit with a coolant source having a lower temperature than the coolant source. In the air conditioning system of Patent Document 1, the heat source supply and discharge base is provided along the subway line outside the vehicle. Also, in a moving body such as a vehicle, the capacity of the power supply of the air conditioning system is often limited, and reduction of the power consumption required for air conditioning is demanded.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] To provide a heat storage type air conditioning system capable of reducing the power consumption required for air conditioning.

[0005] The present disclosure provides a heat storage air conditioning system and a control method capable of solving the above problems.

Means for Solving the Problems

[0006] The heat storage air conditioning system of the present disclosure includes a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, a heat storage heat exchanger provided on the downstream side in the refrigerant flow direction of the condenser, an expansion valve provided on the downstream side of the heat storage heat exchanger, an evaporator that vaporizes the refrigerant decompressed by the expansion valve, a main pipe through which the refrigerant passes and connects the compressor, the condenser, the heat storage heat exchanger, the expansion valve, and the evaporator, a heat storage tank that stores a heat storage material, a pump that sends the heat storage material to the heat storage heat exchanger, and a heat storage material flow path through which the heat storage material passes and connects the heat storage tank, the pump, and the heat storage heat exchanger.

[0007] Further, the control method of the present disclosure is applied to a heat storage air conditioning system including a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, a heat storage heat exchanger provided on the downstream side in the refrigerant flow direction of the condenser, an expansion valve provided on the downstream side of the heat storage heat exchanger, an evaporator that vaporizes the refrigerant decompressed by the expansion valve, a main pipe through which the refrigerant passes and connects the compressor, the condenser, the heat storage heat exchanger, the expansion valve, and the evaporator, a heat storage tank that stores a heat storage material, a pump that sends the heat storage material to the heat storage heat exchanger, and a heat storage material flow path through which the heat storage material passes and connects the heat storage tank, the pump, and the heat storage heat exchanger. The compressor is operated at a rotation speed such that the difference from the minimum rotation speed is within a predetermined range, and the pump is operated at a predetermined rotation speed less than the upper limit value.

Advantages of the Invention

[0008] According to the above-described heat storage air conditioning system and control method, the power consumption required for air conditioning can be reduced.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

MODE FOR CARRYING OUT THE INVENTION

[0010] <Embodiment> Hereinafter, the planning system according to each embodiment will be described with reference to FIGS. 1 to 9. (Configuration) FIG. 1 is a diagram showing an example of a heat storage air conditioning system according to an embodiment. The heat storage air conditioning system 100 is a heat storage type cooling system suitable for a moving body such as a vehicle with restrictions on installation space, power supply capacity, etc. The vehicle may be an EV (Electric Vehicle), an AGT (Automated Guideway Transit) driven by a battery without power supply by a pantograph, or the like. As shown in FIG. 1, the heat storage air conditioning system 100 includes a compressor 1, a condenser 2, a three-way valve 8a, a three-way valve 8b, a third expansion valve 6, a heat storage / radiator 11, a three-way valve 8c, a first expansion valve 3, an evaporator 4, pipes P1, P2, P3, and P4 connecting them, a second expansion valve 5 provided in the pipe P2, a heat storage tank 12, a pump 13, and a pipe P5 connecting the heat storage tank 12, the pump 13, and the heat storage / radiator 11, and a control device 10. A refrigerant flows through the pipes P1 to P4. A liquid heat storage material flows through the pipe P5. The configuration shown in FIG. 1 schematically shows the basic configuration of the heat storage air conditioning system 100, and may further include other components.

[0011] One end of the pipe P2 is connected to the pipe P1 on the downstream side of the condenser 2 and the upstream side of the third expansion valve 6, and the other end is connected to the pipe P1 on the downstream side of the first expansion valve 3 and the upstream side of the evaporator 4, and is provided so as to form a refrigerant flow path that bypasses the third expansion valve 6, the heat storage / radiator 11, and the first expansion valve 3. The upstream side and the downstream side mean the upstream side and the downstream side in the direction in which the refrigerant flows. A three-way valve 8a is provided at the connection point on the upstream side of the pipe P2 and the pipe P1. By controlling the three-way valve 8a, the flow rates of the refrigerant flowing through the pipes P1 and P2 can be adjusted.

[0012] One end of the pipe P3 is connected to the pipe P1 on the downstream side of the three-way valve 8a and the upstream side of the third expansion valve 6, and the other end is connected to the pipe P1 on the downstream side of the third expansion valve 6 and the upstream side of the heat storage / radiator 11, and is provided so as to form a refrigerant flow path that bypasses the third expansion valve 6. A three-way valve 8b is provided at the connection point on the upstream side of the pipe P3 and the pipe P1. By controlling the three-way valve 8b, the flow rates of the refrigerant flowing through the third expansion valve 6 and the pipe P3 can be adjusted.

[0013] One end of the pipe P4 is connected to the pipe P1 downstream of the heat accumulator / radiator 11 and upstream of the first expansion valve 3, and the other end is connected to the pipe P1 downstream of the first expansion valve 3 and upstream of the evaporator 4, and is provided to form a refrigerant flow path bypassing the first expansion valve 3. A three-way valve 8c is provided at the connection point between the upstream side of the pipe P4 and the pipe P1. By controlling the three-way valve 8c, the flow rates of the refrigerant flowing through the first expansion valve 3 and the pipe P4 can be adjusted.

[0014] The compressor 1 compresses the refrigerant and discharges high-pressure refrigerant. This high-pressure refrigerant is supplied to the condenser 2. The high-pressure refrigerant supplied to the condenser 2 exchanges heat with the outside air or the like and dissipates heat, and is condensed and liquefied. The first expansion valve 3, the second expansion valve 5, and the third expansion valve 6 all reduce the pressure of the condensed refrigerant. These expansion valves are used or not used depending on the purpose by switching the refrigerant flow by the three-way valves 8a to 8c. The switching of the first expansion valve 3 to the third expansion valve 6 will be described later.

[0015] The heat accumulator / radiator 11 exchanges heat between the refrigerant flowing through the pipe P1 and the heat storage material flowing through the pipe P5. The heat accumulator / radiator 11 is, for example, a plate-type heat exchanger. When the heat accumulator / radiator 11 cools the refrigerant with the heat storage material, the heat storage material functions as a heat accumulator by taking heat from the refrigerant and storing it. On the contrary, when the refrigerant cools the heat storage material, it functions as a radiator by dissipating heat from the heat storage material. When the heat accumulator / radiator 11 functions as a heat accumulator, the refrigerant flows into the heat accumulator / radiator 11 via the pipe P3 without passing through the third expansion valve 6. The refrigerant flowing into the heat accumulator / radiator 11 exchanges heat with the heat storage material in the heat accumulator / radiator 11 and is cooled, and is depressurized by the first expansion valve 3 to become a low-pressure and low-temperature refrigerant, and is sent to the evaporator 4.

[0016] When the heat accumulator / radiator 11 functions as a radiator, the refrigerant is depressurized by the third expansion valve 6 to become a low-pressure and low-temperature refrigerant and flows into the heat accumulator / radiator 11. The refrigerant flowing into the heat accumulator / radiator 11 exchanges heat with the heat storage material in the heat accumulator / radiator 11 and absorbs the heat of the heat storage material. The refrigerant passing through the heat accumulator / radiator 11 is sent to the evaporator 4 via the pipe P4 without passing through the first expansion valve 3. Alternatively, when the heat accumulator / radiator 11 is not used, the refrigerant passes through the pipe P5, is depressurized by the second expansion valve 5, and then flows into the evaporator 4.

[0017] The low-pressure refrigerant depressurized and expanded by any one of the first expansion valve 3 to the third expansion valve 6 is supplied to the evaporator 4. The low-pressure refrigerant supplied to the evaporator 4 absorbs heat from the indoor air supplied by the fan 7 and vaporizes, and the vaporized refrigerant is sucked into the compressor 1. The refrigerant is again made into a high-pressure refrigerant by the compressor 1 and circulates through the above path. The air cooled by the evaporator 4 is supplied to the interior of the vehicle.

[0018] The heat storage material supplied to the heat accumulator / radiator 11 that exchanges heat with the refrigerant is stored in the heat storage tank 12, and by driving the pump 13, the heat storage material is supplied from the heat storage tank 12 to the heat accumulator / radiator 11. The heat storage tank 12, the pump 13, and the heat accumulator / radiator 11 are connected by the pipe P5, and by driving the pump 13, the heat storage material circulates through the pipe P5 among the heat storage tank 12, the pump 13, and the heat accumulator / radiator 11. The heat storage material is, for example, LLC (Long Life Coolant) cooled to about 5°C initially. For example, a temperature sensor 14 for measuring the temperature of the heat storage material is provided in the heat storage tank 12. The temperature of the heat storage material measured by the temperature sensor 14 is transmitted to the control device 10.

[0019] The control device 10 is a computer such as a microcomputer. The control device 10 controls the opening and closing and the opening degree of the three-way valves 8a to 8c, the opening degree of the first expansion valve 3, the second expansion valve 5, and the third expansion valve 6, the start / stop and the rotation speed control of the compressor 1, the start / stop and the rotation speed control of the pump 13, and the start / stop and the rotation control of the fan 7. For example, the control device 10 switches the three-way valves 8a to 8c or changes the rotation speeds of the compressor 1 and the pump 13 according to the temperature of the heat storage material measured by the temperature sensor 14, so as to control the heat storage air-conditioning system 100 to cool the interior to a desired set temperature.

[0020] (Cooling operation 1: Cooling operation using the heat storage system) Next, with reference to FIGS. 2 to 7, the control during the cooling operation of the heat storage air-conditioning system 100 will be described. FIG. 2 shows the flow of the refrigerant in the heat storage air-conditioning system 100 at the start of the cooling operation. When the cooling operation is started, the control device 10 controls the three-way valve 8a so that the refrigerant does not flow through the pipe P2, controls the three-way valve 8b so that the refrigerant does not flow through the third expansion valve 6, and controls the three-way valve 8c so that the refrigerant does not flow through the pipe P4 and flows through the first expansion valve 3. Further, the control device 10 operates the compressor 1 at a predetermined rotation speed or less, for example, at the minimum rotation speed. Also, the control device 10 operates the pump 12 at a predetermined rotation speed less than the maximum rotation speed. By such control, the refrigerant and the heat storage material flow in the direction of the arrow through the thick-line flow path in FIG. 2. This operation is called a cooling operation using the heat storage system (or cooling operation 1). Even when the compressor 1 is operated at a low speed, since the refrigerant is cooled by the heat storage material in the heat storage / radiator 11, sufficient cooling performance can be obtained. For example, the control device 10 controls the rotation speed of the pump 12 according to the set temperature of the cooling and the temperature in the vehicle interior, and adjusts the flow rate of the heat storage material, so as to control the vehicle interior to reach the set temperature. Also, from the viewpoint of power saving, it is preferable that the compressor 1 be operated at a low speed as much as possible, but according to the difference between the set temperature of the cooling and the temperature in the vehicle interior, not only the pump 12 but also the rotation speed of the compressor 1 may be adjusted.

[0021] If such operation continues, due to the heat exchange with the refrigerant, the temperature of the heat storage material gradually rises, and the ability of the heat storage material to cool the refrigerant decreases. Then, the control device 10 increases the rotation speed of the pump 12 to increase the flow rate of the heat storage material. For example, the control device 10 stores a table that defines the correspondence between the temperature of the heat storage material and the rotation speed of the pump 12, and based on the temperature of the heat storage material measured by the temperature sensor 14 and this table, the rotation speed of the pump 12 may be controlled. When the ability of the heat storage material to cool the refrigerant is maintained by increasing the flow rate of the heat storage material, the cooling operation using the heat storage system can be continued, and power saving can be achieved.

[0022] (Cooling operation 2: Cooling operation by refrigeration cycle) When the temperature of the heat storage material rises and it becomes impossible to cool the refrigerant even if the rotation speed of the pump 12 is increased, the control device 10 controls the three-way valve 8a so that the refrigerant flows through the pipe P2 and does not flow through the heat storage / radiator 11. Further, the control device 10 operates the compressor 1 at a rotation speed such that the set temperature for cooling can be achieved, and stops the pump 12. By such control, the refrigerant flows in the direction of the arrow through the thick-line flow path in FIG. 3. Thereby, the cooling operation can be continued without using the heat storage material. This operation is called a cooling operation by refrigeration cycle (or cooling operation 2).

[0023] The state change of the refrigerant when performing the cooling operations 1 and 2 is shown in the Mollier diagram of FIG. 4. In FIG. 4, each symbol indicates the following state. That is, A1 is the state (vapor phase) of the high-temperature and high-pressure refrigerant discharged from the compressor 1 when the heat accumulator / radiator 11 shown in FIG. 3 is not used (in the case of cooling operation 2), A2 is the state (liquid phase) of the refrigerant at the outlet side of the condenser 2 in that case, A5 is the state (liquid phase) of the refrigerant at the inlet side of the evaporator 4, and A6 is the state (vapor phase) of the refrigerant at the outlet side of the evaporator 4. On the other hand, A3 is the state (vapor phase) of the refrigerant discharged from the compressor 1 in the cooling operation 1 shown in FIG. 2, A4 is the state (liquid phase) of the refrigerant at the outlet side of the condenser 2 in the cooling operation 1 shown in FIG. 2, A5 is the state (liquid phase) of the refrigerant at the inlet side of the evaporator 4, and A6 is the state (vapor phase) of the refrigerant at the outlet side of the evaporator 4. The cooling operation 1 can reduce the work of the compressor 1 required for the enthalpy increase by an amount of L1 - L2 compared to the cooling operation 2.

[0024] FIG. 5 shows the power consumption of the cooling operations 1 and 2. The vertical axis of FIG. 5 represents the power consumption (W), and the horizontal axis represents the operation time. T1 is the time when switching from the cooling operation 1 to the cooling operation 2. The dashed-line graph shows the power consumption of the entire heat storage air-conditioning system 100, and the solid-line graph shows the transition of the power consumption of the compressor 1. As shown in the figure, by performing the cooling operation 1 that suppresses the rotation speed of the compressor 1 using the heat storage material, the power consumption can be reduced. For example, in a mobile body powered only by a battery, it is necessary to use the power of the battery to move to the destination with priority over air conditioning. According to the heat storage air-conditioning system 100, the cooling operation 1 can reduce the power consumption required for air conditioning, and more power can be used for movement.

[0025] (Cooling operation 3: Cooling operation by a refrigeration cycle involving cooling of the heat storage material) When the temperature of the heat storage material rises, it is possible to continue cooling by the cooling operation 2. However, if the cooling operation 2 continues, the power consumption will increase. Therefore, while performing the cooling operation, an operation of using the heat accumulator / radiator 11 as a radiator to cool the heat storage material is performed. For example, the control device 10 controls the three-way valves 8a to 8c so that the refrigerant flows through the third expansion valve 6 and does not flow through the first expansion valve 3 and the second expansion valve 5. Further, the control device 10 operates the compressor 1 at a rotation speed such that the set temperature for cooling can be achieved. Further, the control device 10 operates the pump 12 at a predetermined rotation speed. By such control, the refrigerant and the heat storage material flow in the thick line flow path in FIG. 6 in the direction of the arrow. The refrigerant that has passed through the condenser 2 is depressurized by the third expansion valve 6 to become a low-temperature refrigerant. In the heat accumulator / radiator 11, the heat storage material is cooled by heat exchange between the low-temperature refrigerant and the heat storage material. The refrigerant that has absorbed heat in the heat accumulator / radiator 11 exchanges heat with the indoor air in the evaporator 4 to cool the interior. Thereby, the heat storage material whose temperature has risen by the cooling operation 1 can be cooled. This operation is called a cooling operation (or cooling operation 3) by a refrigeration cycle involving cooling of the heat storage material.

[0026] Another aspect of the cooling operation by the refrigeration cycle involving cooling of the heat storage material is shown in FIG. 7. That is, the control device 10 controls the three-way valves 8a to 8c so that the refrigerant flows through the third expansion valve 6 and the second expansion valve 5 and does not flow through the first expansion valve 3. Even by such control, the heat storage material can be cooled. This operation is called the cooling operation 4.

[0027] The control device 10 cools the heat storage material while continuing the cooling operation by the refrigeration cycle shown in FIG. 6 or FIG. 7. Then, when the temperature measured by the temperature sensor 14 reaches a predetermined temperature (for example, 5°C), the control device 10 switches back to the cooling operation 1 in FIG. 2 and continues the cooling operation. Thereby, the power consumption of the heat storage air conditioning system 100 can be reduced.

[0028] (Device of heat storage tank) Further, as a measure for increasing the heat storage capacity of the heat storage material, a latent heat storage material may be mounted in the heat storage tank 12. FIG. 8 shows a cross section of the heat storage tank 12 equipped with the latent heat storage material. The oval member in FIG. 8 is the latent heat storage material 15. The latent heat storage material 15 is, for example, a tube-shaped container filled with a latent heat storage material having a larger heat capacity than the heat storage material. A large number of latent heat storage materials 15 are mounted inside the heat storage tank 12 so that the liquid heat storage material flows between the latent heat storage materials 15. Heat exchange is performed between the heat storage material in the heat storage tank 12 and the latent heat storage material 15, and the temperature of the heat storage tank 12 can be kept low for a long time, and the cooling operation 1 (cooling operation using the heat storage system) can be carried out for a long time. Thereby, the power consumption of the heat storage air conditioning system 100 can be reduced. Further, by mounting the latent heat storage material 15 in the heat storage tank 12, the cooling capacity of the heat storage material can be maintained for a long time, so that many heat storage materials are not required, and the heat storage tank 12 can be lightened and made compact. Thereby, it is possible to expect an improvement in the fuel efficiency of the moving body and a reduction in the power consumption required for movement. Further, due to the compactness of the heat storage tank 12, the degree of freedom of mounting is improved, and the strength reinforcement on the vehicle side for mounting the heat storage tank 12 becomes unnecessary.

[0029] (Operation) Next, with reference to FIG. 9, an example of the control of the heat storage air conditioning system 100 according to the embodiment will be described. When the cooling operation is started, the control device 10 performs a cooling operation using the heat storage system (step S1). That is, the control device 10 performs a cooling operation in the mode of the cooling operation 1 illustrated in FIG. 2. The control device 10 operates the compressor 1 at a rotation speed, for example, such that the difference from the minimum rotation speed is within a predetermined range, and operates the pump 12 at a rotation speed less than the upper limit. The control device 10 monitors the temperature of the heat storage material measured by the temperature sensor 14, and when the temperature of the heat storage material becomes equal to or higher than a predetermined first threshold value (step S2; Yes), the rotation speed of the pump 12 is increased, and the flow rate of the heat storage material supplied to the heat storage device / radiator 11 is increased (step S3). When the temperature of the heat storage material is less than the first threshold value (step S2; No), the control device 10 continues the cooling operation 1. The first threshold value is a value less than the upper limit of the temperature of the heat storage material that rises in temperature by heat exchange with the refrigerant.

[0030] Even after the rotational speed of the pump 12 increases, the control device 10 monitors the temperature of the heat storage material measured by the temperature sensor 14. When the temperature of the heat storage material is less than a predetermined second threshold value (step S4; No), the control device 10 continues the control of step S3. The second threshold value is a temperature higher than the first threshold value and at which the heat storage material can no longer cool the refrigerant (a predetermined temperature at which heat absorption from the refrigerant becomes impossible). When the temperature of the heat storage material becomes equal to or higher than the second threshold value (step S4; Yes), the cooling operation using the heat storage system is switched to the cooling operation by the refrigeration cycle (step S5). That is, the control device 10 performs the cooling operation in any of the modes of the cooling operations 2 to 4 illustrated in FIGS. 3, 6, and 7. It can be arbitrarily selected which of the cooling operations 2 to 4 is used to execute the cooling operation. Also, it may be possible to arbitrarily switch the cooling operations 2 to 4 during the execution of the cooling operation by the refrigeration cycle. For example, until the indoor temperature reaches the set temperature, the cooling operation 2 is performed, and when the indoor temperature reaches the set temperature and enters the phase of maintaining the indoor temperature at the set temperature, the heat storage material may be cooled by the cooling operation 3 or the cooling operation 4. The switching of the cooling operations 2 to 4 may be performed by the control device 10 or may be switched according to a user's instruction. Even during the execution of the cooling operation by the refrigeration cycle, the control device 10 monitors the temperature of the heat storage material measured by the temperature sensor 14. When the temperature of the heat storage material is higher than a predetermined third threshold value (step S6; No), the control device 10 continues the control of step S5. For the third threshold value, for example, the initial temperature of the heat storage material (for example, 5°C) or a value close thereto is set. When the temperature of the heat storage material becomes equal to or lower than the third threshold value (step S6; Yes), the cooling operation by the refrigeration cycle is switched to the cooling operation using the heat storage system (step S1). During the execution of the cooling operation, the control device 10 repeatedly executes the control of steps S1 to S6. Thus, according to the heat storage air-conditioning system 100, by performing the cooling operation using the heat storage system (cooling operation 1), the power consumption can be reduced. Also, after the heat storage temperature has risen, the cooling operation can be continued by the cooling operation by the refrigeration cycle (cooling operations 2 to 4), the heat storage material can be cooled by using the heat accumulator / radiator 11 as a radiator (cooling operations 3 to 4), and the cooling operation using the heat storage system (cooling operation 1) can be executed again.

[0031] (Effect) As described above, according to the present embodiment, the heat accumulator / radiator 11 and the heat storage tank 12 are provided separately, and these are connected by the pipe P5, and when necessary, the heat storage material is supplied to the heat accumulator / radiator 11 by driving the pump 13. Thereby, even when a large heat storage tank 12 is required to store the heat storage material necessary for cooling, by arranging the heat storage tank 12 in a place where the heat storage tank 12 can be stored, the cooling operation using the heat storage system can be performed. Generally, an air conditioning system mounted on a vehicle or the like has restrictions on the mounting space. Due to this restriction, when only a small-capacity heat storage tank can be mounted, when the cooling load becomes high, the heat storage capacity of the heat storage tank may be insufficient and cooling may become impossible. On the other hand, in the heat storage air conditioning system 100 of the present embodiment configured such that the heat accumulator / radiator 11 and the heat storage tank 12 can be arranged in separate places, it is easy to install even in a moving body with many spatial restrictions, and by storing a sufficient amount of heat storage material in the heat storage tank 12, the cooling operation using the heat storage system can be performed for a longer time. Further, although EV vehicles and battery-driven AGTs without power supply by a pantograph are becoming popular, in these moving bodies, when the remaining battery level becomes a problem, in the heat storage air conditioning system 100 of the present embodiment, by using the heat storage material, the power consumption of the compressor 1 can be reduced, and a large power saving effect can be expected. Also, by adjusting the output of the pump 12, the heat exchange performance in the heat accumulator / radiator 11 can be controlled. For example, by increasing the output of the pump 12 even after the temperature of the heat storage material has risen above a certain level, the cooling operation using the heat storage system can be continued.

[0032] Also, by using the heat accumulator / radiator 11 as a plate type heat exchanger, equivalent performance can be obtained even if the size is made more compact compared to a fan coil type heat exchanger. Thereby, it is easy to install even in a moving body with many spatial restrictions.

[0033] In the cooling operation 1, the heat storage material cools the high-temperature refrigerant discharged by the compressor 1. Since the refrigerant can be cooled by the low-temperature heat storage material, the compressor 1 can be operated, for example, at the minimum rotational speed, and the power consumption of the compressor 1 and the refrigeration cycle can be reduced.

[0034] In the cooling operations 3 and 4, the heat storage material is cooled by exchanging heat with the low-temperature refrigerant that has passed through the third expansion valve 6. Since the heat storage material can be cooled by the refrigeration cycle in the heat storage air-conditioning system 100, there is no need to provide external equipment such as a heat source supply and exhaust device.

[0035] In addition, by mounting the latent heat storage material 15 in the heat storage tank 12, the cooling capacity of the heat storage material can be improved, and the weight reduction and compactification of the heat storage tank 12 can be achieved. As a result, further reduction of power consumption can be achieved, and the heat storage air-conditioning system 100 can be introduced without being concerned about space constraints.

[0036] As described above, several embodiments according to the present disclosure have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, as well as in the invention described in the claims and its equivalent scope.

[0037] <Appendix> The heat storage air-conditioning system and the control method described in each embodiment can be understood, for example, as follows.

[0038] (1) The heat storage air conditioning system 100 according to the first aspect includes a compressor 1 that compresses a refrigerant, a condenser 2 that condenses the refrigerant compressed by the compressor 1, a heat storage heat exchanger 11 provided on the downstream side in the refrigerant flow direction of the condenser 2, an expansion valve 3 provided on the downstream side of the heat storage heat exchanger 11, an evaporator 4 that vaporizes the refrigerant decompressed by the expansion valve 3, a main pipe P1 through which the refrigerant flows and connects the compressor 1, the condenser 2, the heat storage heat exchanger 11, the expansion valve 3, and the evaporator 4, a heat storage tank 12 that stores a heat storage material, a pump 13 that sends the heat storage material to the heat storage heat exchanger 11, and a heat storage material pipe P5 through which the heat storage material flows and connects the heat storage tank 12, the pump 13, and the heat storage heat exchanger 11. Accordingly, an external device for waste heat is not required, and a heat storage type air conditioning system that can be mounted on a moving body can be realized.

[0039] (2) The heat storage air conditioning system 100 according to the second aspect is the heat storage air conditioning system 100 of (1), and further includes a bypass pipe P2 that bypasses the heat storage heat exchanger 11 and the expansion valve 3 provided on the downstream side of the condenser, a second expansion valve 5 provided on the bypass pipe, and a first valve 8a that adjusts the flow rate of the refrigerant flowing through the bypass pipe and the flow rate of the refrigerant flowing through the main pipe provided at a branch point between the bypass pipe and the main pipe. Accordingly, a cooling operation (cooling operation 2) by a refrigeration cycle becomes possible.

[0040] (3) The heat storage air conditioning system 100 according to the third aspect is the heat storage air conditioning system 100 of (1) to (2), and further includes a second bypass pipe P4 that bypasses the expansion valve 3, a third expansion valve 6 provided between the condenser 2 and the heat storage heat exchanger 11, and a second valve 8c that adjusts the flow rate of the refrigerant flowing through the second bypass pipe and the flow rate of the refrigerant flowing through the main pipe provided at a branch point between the second bypass pipe P4 and the main pipe P1. Accordingly, a cooling operation (cooling operations 3 and 4) by a refrigeration cycle involving cooling of the heat storage material becomes possible.

[0041] (4) The heat storage air conditioning system 100 according to the fourth aspect is the heat storage air conditioning system 100 of (1) to (3), and a latent heat storage material 15 is mounted in the heat storage tank 12. Thereby, the cooling capacity of the heat storage material can be improved, and the heat storage tank 12 can be made compact.

[0042] (5) The heat storage air conditioning system 100 according to the fifth aspect is the heat storage air conditioning system 100 of (1) to (4), and further includes a control device 10 that operates the compressor at a rotation speed such that the difference from the minimum rotation speed is within a predetermined range, and operates the pump at a predetermined rotation speed less than the upper limit value. Thereby, the power consumption of the compressor 1 can be reduced.

[0043] (6) The heat storage air conditioning system 100 according to the sixth aspect is the heat storage air conditioning system 100 of (5), and when the temperature of the heat storage material becomes equal to or higher than a predetermined first threshold value, the control device increases the rotation speed of the pump. Thereby, the time of the cooling operation by the cooling operation 1 can be lengthened, and the power consumption of the compressor 1 can be reduced.

[0044] (7) The heat storage air conditioning system 100 according to the seventh aspect is the heat storage air conditioning system 100 of (1) to (6), and further includes a control device 10 that controls the first valve so that when the temperature of the heat storage material rises to a predetermined temperature at which heat cannot be absorbed from the refrigerant, the refrigerant flows through the bypass pipe P2 instead of flowing through the main pipe P1. Thereby, the cooling operation can be continued even after the temperature of the heat storage material has risen.

[0045] (8) The heat storage air conditioning system 100 according to the eighth aspect is the heat storage air conditioning system 100 of (1) to (7), and further includes a control device 10 that controls the second valve 8c so that the refrigerant flows through the second bypass pipe P4 instead of flowing through the main pipe P1. Thereby, the heat storage material can be cooled.

[0046] (9) The control method according to the ninth aspect is an air-conditioning system with heat storage including a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, a heat storage heat exchanger provided on the downstream side in the refrigerant flow direction of the condenser, an expansion valve provided on the downstream side of the heat storage heat exchanger, an evaporator that vaporizes the refrigerant decompressed by the expansion valve, a main pipe through which the refrigerant passes and that connects the compressor, the condenser, the heat storage heat exchanger, the expansion valve, and the evaporator, a heat storage tank that stores a heat storage material, a pump that sends the heat storage material to the heat storage heat exchanger, and a heat storage material flow path through which the heat storage material passes and that connects the heat storage tank, the pump, and the heat storage heat exchanger. In the air-conditioning system with heat storage, the compressor is operated at a rotation speed such that the difference from the minimum rotation speed is within a predetermined range, and the pump is operated at a predetermined rotation speed less than the upper limit value.

Explanation of Signs

[0047] 100 ··· Air-conditioning system with heat storage 1 ··· Compressor 2 ··· Condenser 3 ··· First expansion valve 4 ··· Evaporator 5 ··· Second expansion valve 6 ··· Third expansion valve 7 ··· Fan 8a, 8b, 8c ··· Three-way valve 10 ··· Control device 11 ··· Heat storage device / radiator 12 ··· Heat storage tank 13 ··· Pump 14 ··· Temperature sensor P1, P2, P3, P4 ··· Pipe P5 ··· Pipe

Claims

1. A compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, a heat storage heat exchanger provided on the downstream side in the refrigerant flow direction of the condenser, an expansion valve provided on the downstream side of the heat storage heat exchanger, an evaporator that vaporizes the refrigerant decompressed by the expansion valve, a main pipe through which the refrigerant passes and that connects the compressor, the condenser, the heat storage heat exchanger, the expansion valve, and the evaporator, a heat storage tank that stores a heat storage material, a pump that sends the heat storage material to the heat storage heat exchanger, a heat storage material flow path through which the heat storage material passes and that connects the heat storage tank, the pump, and the heat storage heat exchanger, A heat storage air conditioning system comprising the above.

2. A bypass pipe provided on the downstream side of the condenser and bypassing the heat storage heat exchanger and the expansion valve, a second expansion valve provided in the bypass pipe, a first valve provided at a branch point between the bypass pipe and the main pipe and that adjusts the flow rate of the refrigerant flowing through the bypass pipe and the flow rate of the refrigerant flowing through the main pipe, The heat storage air conditioning system according to claim 1, further comprising the above.

3. A second bypass pipe that bypasses the expansion valve, a third expansion valve provided between the condenser and the heat storage heat exchanger, a second valve provided at a branch point between the second bypass pipe and the main pipe and that adjusts the flow rate of the refrigerant flowing through the second bypass pipe and the flow rate of the refrigerant flowing through the main pipe, The heat storage air conditioning system according to claim 1 or claim 2, further comprising the above.

4. The heat storage air conditioning system according to claim 1 or claim 2, further comprising a latent heat storage material mounted in the heat storage tank.

5. A control device that operates the compressor at a rotational speed such that the difference from the minimum rotational speed is within a predetermined range and operates the pump at a predetermined rotational speed less than the upper limit, The heat storage air conditioning system according to claim 1, further comprising the above.

6. The control device, when the temperature of the heat storage material becomes equal to or higher than a predetermined first threshold value, increases the rotational speed of the pump, The heat storage air conditioning system according to claim 5.

7. A control device that controls the first valve such that when the temperature of the heat storage material rises to a predetermined temperature at which heat absorption from the refrigerant becomes impossible, the refrigerant flows through the bypass pipe instead of through the main pipe, The heat storage air conditioning system according to claim 2, further comprising the above.

8. ​ A control device that controls the second valve so that the refrigerant flows through the second bypass pipe without flowing through the main pipe. The heat storage air-conditioning system according to claim 3, further comprising the same.

9. In a heat storage air-conditioning system comprising a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, a heat storage heat exchanger provided downstream in the refrigerant flow direction of the condenser, an expansion valve provided downstream of the heat storage heat exchanger, an evaporator that vaporizes the refrigerant decompressed by the expansion valve, a main pipe through which the refrigerant passes and connects the compressor, the condenser, the heat storage heat exchanger, the expansion valve, and the evaporator, a heat storage tank that stores a heat storage material, a pump that sends the heat storage material to the heat storage heat exchanger, and a heat storage material flow path through which the heat storage material passes and connects the heat storage tank, the pump, and the heat storage heat exchanger. A control method in which the compressor is operated at a rotational speed such that the difference from the minimum rotational speed is within a predetermined range, and the pump is operated at a predetermined rotational speed less than the upper limit value.

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