A single-pump driven phase change cold accumulation laser thermal management system

Abstract

The utility model belongs to the technical field of laser heat management, disclose a kind of single pump driven phase change cold storage laser heat management system, including refrigeration unit, cold storage unit and liquid supply unit three parts;Refrigeration unit uses vapor compression refrigeration cycle to generate cold, supply cold storage unit and liquid supply unit;The inside of cold storage unit is filled with solid-liquid phase change material as cold storage material to store cold, supply liquid supply unit;Liquid supply unit uses adjustable speed circulating pump to provide circulating power, improve rotational speed during laser operation to realize large-flow liquid supply, satisfy the heat exchange power demand of laser short-time high-power thermal load, reduce rotational speed during laser non-operation, match the power refrigeration heat exchange demand corresponding to homogenization after high-power thermal load.The utility model uses the advantage of solid-liquid phase change cold storage high energy storage density, improves the energy storage density of cold storage unit, reduces system volume, weight.

Description

Technical Field

[0001] This utility model belongs to the field of laser thermal management technology, and relates to a single-pump driven phase change cold storage laser thermal management system. Background Technology

[0002] Laser technology is now widely used in medical, industrial, and defense fields. With the development of laser technology, the output power and beam quality of lasers are constantly improving, the power-to-volume ratio is gradually increasing, and the corresponding thermal power is multiplying. The accumulation of heat inside the laser leads to an increase in internal temperature, resulting in wavelength shift, reduced optical power and conversion efficiency. Simultaneously, temperature changes cause thermal stress within the laser, leading to laser beam distortion, and in severe cases, crystal fracture and damage, ultimately harming the laser device. Therefore, a robust thermal management system is crucial for maintaining laser temperature stability and ensuring normal laser operation.

[0003] Common laser heat dissipation methods include air cooling, semiconductor cooling, and liquid cooling. Air cooling removes the heat generated by the laser through forced or natural air convection. However, it has low heat transfer capacity, is greatly affected by the environment, and is only suitable for low-power lasers with less restriction on the operating temperature range. Semiconductor cooling utilizes semiconductor refrigeration technology to control the temperature of the laser attached to the semiconductor heat sink by creating a temperature gradient and heat transfer under the action of current. It has a simple structure and high control precision, but its cooling efficiency is low, making it unsuitable for the heat dissipation needs of high-power lasers. Liquid cooling uses forced convection of a liquid working fluid to remove the heat generated by the laser. With the development of microchannel technology in recent years, the heat dissipation capacity of microchannel liquid cooling has exceeded 100W / cm2, which can meet the high-power heat dissipation requirements of lasers and is the most widely used in the field of laser heat dissipation.

[0004] High-power lasers typically exhibit intermittent operation characteristics, with their thermal loads being characterized by short durations and high power. Therefore, thermal management systems for high-power lasers generally adopt a cold storage mode: during the laser's non-operational periods, cold energy is stored through a cooling cycle, and during the laser's operation, cold energy is introduced through a liquid cooling cycle to cool the laser, thus averaging the short-duration, high-power thermal load of the laser over time and reducing the cooling power requirements of the thermal management system.

[0005] However, the traditional thermal management system has a relatively complex process design. It often uses two circulation pumps, one internal and one external, to transfer the cooling capacity from the refrigeration unit to the cold storage unit and finally to the heat load of the laser. The system requires a lot of power components and regulating valves, and the actuators of many active regulating valves will occupy a large volume and weight. Furthermore, traditional cold storage modules use single-phase sensible heat for cold storage, resulting in low energy density, large volume, and high weight. This severely limits the adaptability of high-power lasers to various low-load platforms and makes it difficult to meet the requirements of lightweight and high mobility for laser use. Using solid-liquid phase change materials as the cold storage medium can significantly improve the energy storage density of the system. However, in current cyclic designs using solid-liquid phase change cold storage, multiple channels are usually embedded in the cold storage module to ensure that the cold storage heat exchanger can meet the functions of storing cold during non-working periods and releasing cold during working periods. For example, the three-channel design of the cold storage heat exchanger in the patent "Cold Storage Thermal Management Device for High-Power Laser Equipment" and the cold storage heat exchanger in the patent "A Phase Change Cold Storage Thermal Management System for High-Power Fiber Lasers" simultaneously embed refrigerant cold pipes and refrigerant flow pipelines. However, the multi-channel setting reduces the filling ratio of solid-liquid phase change materials in the cold storage module, significantly reducing the energy storage density of the system and making it difficult to take advantage of the high energy storage density of solid-liquid phase change materials. Utility Model Content

[0006] (I) Purpose of the utility model

[0007] The purpose of this invention is to address the problems of large size and heavy weight of existing laser thermal management systems by proposing a single-pump driven phase change cold storage laser thermal management system. This system has a simple process, low energy consumption, high temperature control accuracy, and can effectively reduce the weight of the laser thermal management system. It is suitable for the thermal management needs of high-power lasers in various low-load mobile platforms and has good scalability.

[0008] (II) Technical Solution

[0009] To address the aforementioned technical problems, this utility model provides a single-pump driven phase change thermal storage laser thermal management system comprising three parts: a cooling unit, a cold storage unit, and a liquid supply unit. The cooling unit uses a vapor compression refrigeration cycle to generate cooling capacity, which is supplied to the cold storage unit and the liquid supply unit. The cold storage unit is filled with a solid-liquid phase change material as a cold storage material to store cooling capacity, which is then supplied to the liquid supply unit. The liquid supply unit uses an adjustable-speed circulating pump to provide circulation power. During laser operation, the pump speed is increased to achieve a large flow rate of liquid supply, meeting the heat exchange power requirements of the laser under short-term high-power heat load. During non-operational laser operation, the pump speed is reduced to match the lower-power cooling and heat exchange requirements corresponding to the homogenized high-power heat load.

[0010] The system consists of a compressor, fan, condenser, liquid receiver, dryer filter, expansion valve, and plate heat exchanger, forming a refrigeration unit. The refrigeration unit uses a vapor compression refrigeration cycle to generate cooling capacity. The refrigerant is compressed by the compressor, condensed in the condenser by exchanging heat with the external environment, and then evaporates in the plate heat exchanger after passing through the liquid receiver, dryer filter, and expansion valve, transferring the cooling capacity to the refrigerant in the liquid supply unit.

[0011] The cold storage heat exchanger is a cold storage unit in the thermal management system. It can employ heat exchange structures such as tube-fin, plate-fin, and shell-and-tube types. The heat exchanger is filled with a solid-liquid phase change material (PLC) to store cold energy. The PLC can be a mixture of one or more organic materials such as n-tetradecane, n-pentadecanane, and n-hexadecane, or an inorganic material such as water. The key feature is that the PLC temperature range is -10℃ to 20℃, and the latent heat of phase change is higher than 200 kJ / kg, far exceeding the energy density of traditional single-phase energy storage materials (for example, the energy density of a traditional ethylene glycol solution with a 20℃ cold storage temperature difference is only about 60 kJ / kg). This invention utilizes solid-liquid phase change energy storage technology to significantly increase the energy density of the thermal management system and reduce its weight and volume requirements.

[0012] The cold storage heat exchanger adopts a single-channel design, with only the refrigerant flowing through the channel. The system's cold storage and release processes are implemented through a system circulation flow design: during thermal management cold storage, a low-temperature refrigerant flows through the channel, cooling the liquid phase change material and converting it to a solid state, storing cold energy; during thermal management liquid supply, a high-temperature refrigerant that has absorbed heat from the heat load flows through the channel, heating the solid phase change material and converting it to a liquid state, consuming cold energy. In the single-channel design, the cold storage heat exchanger only has a refrigerant flow channel, with only one refrigerant inlet and outlet. Parallel design can be used within the channel to expand the heat exchange area of ​​the refrigerant and enhance heat transfer to ensure the cold storage heat exchanger meets the heat dissipation power requirements of the laser load unit.

[0013] The system comprises a liquid supply unit consisting of a circulating pump, a check valve, a filter, a four-way reversing valve, a flow sensor, a laser heat load, a hot water tank, an electric heater, a regulating valve, and multiple pressure and temperature sensors. The liquid supply unit uses water or ethylene glycol solution as the refrigerant. An adjustable-speed circulating pump powers the unit, increasing its speed during laser operation to achieve a high flow rate and meet the heat exchange power requirements of the laser's short-term high-power heat load. During non-laser operation, the pump speed is reduced to match the lower-power cooling heat exchange requirements corresponding to the homogenized high-power heat load, thereby reducing system energy consumption. A filter removes impurities from the liquid supply unit, and multiple flow, pressure, and temperature sensors monitor the refrigerant's status parameters.

[0014] In the liquid supply unit, the laser load unit is connected in parallel with the plate heat exchanger, and the refrigerant flow is controlled by a one-way valve group to control the components in different operating modes of the system. Regulating valves are connected in front of both the cold storage heat exchanger and the hot water tank, and the cold storage heat exchanger and the hot water tank are connected in parallel. Adjusting the opening of the regulating valves adjusts the fluid flow rate through the cold storage heat exchanger and the hot water tank. During system cold storage, the refrigerant flows only through the cold storage heat exchanger. During system cold release, the liquid supply temperature of the liquid supply unit is controlled by flow regulation to ensure that the thermal management system meets the liquid supply requirements of the load unit.

[0015] The liquid supply unit is equipped with a four-way reversing valve. By switching the four-way reversing valve, the flow direction of the refrigerant in the circulation is changed, thereby changing the system's operating mode and ensuring the normal operation of the system under the single-pump drive and single-channel design of the cold storage heat exchanger. In cold storage mode, the refrigerant flowing from the circulation pump flows into the plate heat exchanger after passing through the filter and the four-way reversing valve. After being cooled by the refrigeration cycle, it flows into the cold storage heat exchanger and stores the cold energy. Then, it flows back into the circulation pump through the four-way reversing valve to complete the circulation. In liquid supply mode, the refrigerant flows into the cold storage heat exchanger and the hot water tank first after passing through the circulation pump and the filter, and then flows through the four-way reversing valve after the direction has been changed. It carries away the cold energy stored in the cold storage heat exchanger and then flows through the load unit. In the load unit, it completes heat exchange to balance the heat generated by the load unit, and then flows back into the circulation pump through the four-way reversing valve to complete the circulation.

[0016] The circulating process design ensures that the refrigerant flows preferentially into the cold storage heat exchanger during the system's liquid supply mode, and then flows back to the circulating pump through the laser load unit. This ensures that the refrigerant pressure at the load unit is at the lowest level in the system, reducing the pressure requirements of the laser load unit and simplifying its design.

[0017] (III) Beneficial Effects

[0018] The single-pump driven phase-change energy storage laser thermal management system provided by the above technical solution has the following beneficial effects:

[0019] (1) Compared with existing heat pipe systems, this system uses solid-liquid phase change materials for cold storage, which can significantly improve the energy storage density of the cold storage unit. The single-channel design in the cold storage unit minimizes the volume and weight of the fluid and heat transfer enhancement structure inside the cold storage heat exchanger. Under the same power requirements and volume constraints, more phase change materials can be filled, maximizing the use of the high energy storage density of solid-liquid phase change cold storage, improving the energy storage density of the cold storage unit, and reducing the system volume and weight.

[0020] (2) The system circulation process design adopts a four-way reversing valve to realize the normal operation of the system function under the single pump drive and the single flow channel design of the cold storage heat exchanger, which reduces the system power equipment and coolant filling requirements, reduces the system volume and weight, and helps to lighten the laser thermal management system.

[0021] (3) In the system circulation design of this utility model, the refrigerant flows into the cold storage heat exchanger first, and then flows back to the circulation pump through the laser load unit, thereby ensuring that the refrigerant pressure at the load unit is at the lowest level in the system, reducing the pressure requirements of the laser load unit, solving the problem of limited pressure resistance of the laser load cold plate, and improving the reliability of system operation. Attached Figure Description

[0022] Figure 1 A schematic diagram of the circulation process of a laser thermal management system;

[0023] Figure 2 A schematic diagram of the coolant circulation in the liquid supply unit of the laser thermal management system under cold storage mode;

[0024] Figure 3 A schematic diagram of a single-select refrigerant circulation system in the liquid supply mode of a laser thermal management system.

[0025] Figure 4 This is a schematic diagram of multiple cold storage units operating in parallel in a thermal management system for a high-power laser. Detailed Implementation

[0026] To make the objectives, contents, and advantages of this utility model clearer, the specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples.

[0027] refer to Figure 1 This utility model provides a schematic diagram of a laser thermal management system. It adopts a single pump driven fluid circuit and changes the flow direction of the refrigerant in the circulation by switching a four-way reversing valve, thereby changing the operating mode of the system and ensuring the normal operation of the system under the single pump drive and single-channel design of the cold storage heat exchanger.

[0028] Figure 1 The diagram illustrates the circulation process of the single-pump driven phase-change thermal storage laser thermal management system of this invention. The single-pump driven phase-change thermal storage laser thermal management system includes three parts: a cooling unit, a cold storage unit, and a liquid supply unit. The cooling unit uses a vapor compression refrigeration cycle to generate cooling capacity, which is supplied to the cold storage unit and the liquid supply unit. The cold storage unit is filled with a solid-liquid phase change material as a cold storage material to store cooling capacity, which is then supplied to the liquid supply unit. The liquid supply unit uses an adjustable-speed circulating pump to provide circulation power. During laser operation, the pump speed is increased to achieve a large flow rate of liquid supply, meeting the heat exchange power requirements of the laser under short-term high-power heat load. During non-operational laser operation, the pump speed is reduced to match the lower-power cooling and heat exchange requirements corresponding to the homogenization of high-power heat load.

[0029] Furthermore, the refrigeration unit includes a compressor 1, a condenser 2, a fan 3, a liquid receiver 4, a dryer filter 5, a throttle valve 6, and a plate heat exchanger 7. This unit adopts a vapor compression refrigeration cycle. The refrigerant is compressed by the compressor 1 and then condensed in the condenser 2 by exchanging heat with the ambient air. After being dried by the dryer filter 5, it is throttled in the throttle valve 6. The plate heat exchanger 7 serves as the evaporator of the refrigeration cycle, in which the refrigerant evaporates and releases cooling energy.

[0030] The cold storage unit includes a cold storage heat exchanger 14. In specific applications, the cold storage heat exchanger adopts a single-channel design and is filled with a solid-liquid phase change material as the cold storage working fluid.

[0031] The liquid supply unit includes a circulating pump 13, a filter 9, a four-way reversing valve 8, a hot water tank 15, an electric heater 16, a regulating valve 17, a laser heat load 18, a flow sensor 19, multiple check valves 10, a pressure sensor 11, and a temperature sensor 12. In specific applications, the liquid supply cycle operates in cold storage mode when the laser is not in operation, transferring the cold energy generated by the refrigeration cycle to the cold storage heat exchanger for storage through the refrigerant circulation. During laser operation, the liquid supply mode operates, transferring the cold energy stored in the cold storage heat exchanger to the laser heat load through the refrigerant to balance the heat generated during laser operation. The two modes of the liquid supply unit are achieved through the switching of the four-way reversing valve combined with the circulation process design. The specific implementation process of the laser thermal management system will be described in detail below.

[0032] (1) Cold storage mode

[0033] Reference Figure 2 When the laser is not in operation, the thermal management system operates in cold storage mode to store cold energy. The cooling unit generates cold energy and stores it in the cold storage unit, while the liquid supply unit is responsible for transferring the cold energy from the cooling unit to the cold storage unit.

[0034] In cold storage mode, all refrigeration unit components, including compressor 1 and fan 3, are operational. Regulation valve 17-1 is completely closed, and the four-way reversing valve 8 is adjusted to open the flow channels in the lower left and upper right directions. During system operation, the refrigerant, driven by circulation pump 13, flows in from the lower direction of the four-way reversing valve 8 and flows out to the left. Subsequently, the refrigerant, blocked by check valve 10-4, cannot flow into the laser heat load 18 and instead enters the plate heat exchanger through check valve 10-5. In the plate heat exchanger, the refrigerant undergoes heat exchange with other refrigerants, its temperature decreases, and it carries away the cold energy, forming a low-temperature refrigerant. After passing through the one-way valve 10-3 and the regulating valve 17-2, it flows into the cold storage heat exchanger, where it exchanges heat with the solid-liquid phase change material. The refrigerant releases cold energy, its temperature rises, and it becomes a high-temperature refrigerant again. The solid-liquid phase change material changes from a liquid state to a solid state to absorb and store the cold energy. After heat exchange, the refrigerant flows back to the four-way reversing valve 8, flowing in from the right and out from the top, before returning to the circulation pump 13 to complete the cycle and realize the transfer of cold energy from the refrigeration unit to the cold storage unit.

[0035] (2) Liquid supply mode

[0036] Reference Figure 3 During laser operation, the laser's thermal load generates heat. The thermal management system operates in liquid supply mode to provide the laser's thermal load with the required temperature, pressure, and flow rate of coolant. The system uses the cold energy stored in the cold storage unit to balance the heat generated by the laser's thermal load. The liquid supply unit is responsible for transferring the cold energy from the cold storage unit to the laser's thermal load.

[0037] In liquid supply mode, the refrigeration unit will no longer operate, regulating valve 17-1 will open, and the direction of the four-way reversing valve 8 will be adjusted to open and connect the flow channels in the upper left and lower right directions. When the system is running, the refrigerant, driven by the circulating pump, flows in from the lower direction of the four-way reversing valve 8 and flows out in the right direction. Then the refrigerant flows into the cold storage heat exchanger and the hot water tank. Since the cold storage heat exchanger and the hot water tank are connected in parallel in the system, the refrigerant transfers heat with the solid-liquid phase change material in the cold storage heat exchanger, the temperature decreases, and the cooling capacity is removed. By adjusting the regulating valves 17-1 and 17-2, the flow rate of the refrigerant in the cold storage heat exchanger and the hot water tank can be controlled, thereby controlling the liquid supply temperature of the laser's heat load. The refrigerant flowing through the cold storage heat exchanger and the hot water tank mixes before the one-way valve 10-2. The temperature of the mixed refrigerant is the supply temperature required for the laser's heat load. Since the opening direction of the one-way valve 10-3 is opposite to the current refrigerant flow direction, the refrigerant can only flow into the laser's heat load through the one-way valve 10-2 and cannot enter the flow channel where the plate heat exchanger 7 is located. Afterward, the refrigerant flows into the laser's heat load 18 to release cooling and balance the heat generated during laser operation. Then, it flows from the left to the four-way reversing valve 8 via the flow sensor 19, flows out from the top, and re-enters the circulation pump 13 to complete the circulation, realizing the transfer of cooling from the cold storage unit to the laser's heat load.

[0038] In this invention, the laser thermal management system changes the flow direction of the coolant by switching the orientation of a four-way reversing valve, and is supplemented by a one-way valve group to control the coolant flow in different operating modes, thus ensuring the functionality of the thermal management system. For higher power laser systems, the thermal management system can be as follows: Figure 4 The system employs multiple refrigeration cycles to provide cooling capacity, and multiple cold storage heat exchangers can be connected in parallel to increase the system's cold storage capacity, ensuring that the system can handle the thermal load of higher-power lasers. Simultaneously, during the cold storage process, regulating valve 17 can be opened sequentially, allowing the refrigerant to flow through only a single cold storage heat exchanger at a time, thus sequentially storing cold in the heat exchangers. This method can improve the heat transfer capacity of the fluid side inside the cold storage heat exchanger at a lower flow rate, accelerating the cold storage process. The reduced flow rate requirement lowers the power consumption of the circulating pump during cold storage, thereby reducing the cooling capacity requirement of the refrigeration unit and improving system energy efficiency.

[0039] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A single-pump driven thermal management system for a phase-change energy storage laser, characterized in that, It consists of three parts: a refrigeration unit, a cold storage unit, and a liquid supply unit. The refrigeration unit uses a vapor compression refrigeration cycle to generate cooling capacity, which is supplied to the cold storage unit and the liquid supply unit. The cold storage unit is filled with solid-liquid phase change material as a cold storage material to store cooling capacity and supply it to the liquid supply unit. The liquid supply unit uses an adjustable speed circulating pump to provide circulation power. During laser operation, the speed is increased to achieve a large flow rate of liquid supply, which meets the heat exchange power requirements of the laser under short-term high-power heat load. During non-laser operation, the speed is reduced to match the lower power refrigeration and heat exchange requirements corresponding to the homogenization of high-power heat load.

2. The single-pump driven phase-change cold storage laser thermal management system as described in claim 1, characterized in that, The refrigeration unit includes a compressor (1), a condenser (2), a liquid receiver (4), a dryer filter (5), a throttle valve (6), and a plate heat exchanger (7) connected in a clockwise direction. The liquid receiver (4) stores the refrigerant. After being compressed by the compressor (1), the refrigerant exchanges heat with the ambient air in the condenser (2) and is condensed. After being dried by the dryer filter (5), it is throttled in the throttle valve (6). The plate heat exchanger (7) serves as the evaporator of the refrigeration cycle. The refrigerant evaporates in it, releasing the cooling capacity and transferring the cooling capacity to the liquid supply unit.

3. The single-pump driven phase-change cold storage laser thermal management system as described in claim 2, characterized in that, A fan (3) is arranged on one side of the condenser (2).

4. The single-pump driven phase-change cold storage laser thermal management system as described in claim 2, characterized in that, The cold storage unit includes a cold storage heat exchanger (14), which is connected to the plate heat exchanger (7) and the laser heat load (18) of the liquid supply unit. When the laser is not working, it operates in cold storage mode, which transfers the cold energy generated by the refrigeration unit to the cold storage heat exchanger (14) and stores it through the circulation of the refrigerant. When the laser is working, it operates in liquid supply mode, which transfers the cold energy stored in the cold storage heat exchanger (14) to the laser heat load (18) through the refrigerant.

5. The single-pump driven phase-change cold storage laser thermal management system as described in claim 4, characterized in that, The cold storage heat exchanger (14) adopts a tube-fin type, plate-fin type, or shell-and-tube heat exchange structure. The solid-liquid phase change material filled inside the cold storage heat exchanger (14) is a mixture formed by one or more of the organic n-tetradecane, n-pentadecanane, and n-hexadecane, or an inorganic material such as water. The solid-liquid phase change temperature of the solid-liquid phase change material is in the range of -10℃ to 20℃, and the latent heat of solid-liquid phase change is higher than 200kJ / kg.

6. The single-pump driven phase-change cold storage laser thermal management system as described in claim 5, characterized in that, The heat storage heat exchanger adopts a single-channel design, in which only the refrigerant flows. During the non-working time of the laser, in the heat storage mode, the low-temperature refrigerant flows in the channel to cool the liquid phase change material and turn it into a solid state, storing the cold energy. During the working period of the laser, in the liquid supply mode, the high-temperature refrigerant that has absorbed the heat load flows in the channel to heat the solid phase change material and turn it into a liquid state, consuming the cold energy.

7. The single-pump driven phase-change cold storage laser thermal management system as described in claim 6, characterized in that, The liquid supply unit includes a circulating pump (13), a filter (9), a four-way reversing valve (8), a hot water tank (15), an electric heater (16), multiple regulating valves, a laser heat load (18), a flow sensor (19), multiple check valves, multiple pressure sensors, and multiple temperature sensors. The left port of the four-way reversing valve (8) is connected to the plate heat exchanger (7) through a check valve. The hot water tank (15), regulating valve, check valve, pressure sensor, temperature sensor, laser heat load (18), flow sensor (19), and check valve are connected in series from the right port to the left port. The circulating pump (13), pressure sensor, temperature sensor (12), check valve, filter (9), and pressure sensor are connected in series between the upper port and the lower port. The cold storage heat exchanger (14) is connected in parallel with the hot water tank (15) and the regulating valve after being connected in series with a regulating valve.

8. The single-pump driven phase-change cold storage laser thermal management system as described in claim 7, characterized in that, The liquid supply unit uses water or ethylene glycol solution as the refrigerant.

9. The single-pump driven phase-change cold storage laser thermal management system as described in claim 8, characterized in that, The laser heat load (18) in the liquid supply unit is connected in parallel with the plate heat exchanger (7), and the refrigerant flows in different operating modes of the system through a one-way valve; the cold storage heat exchanger (14) and the hot water tank (15) are both connected to regulating valves, and the cold storage heat exchanger (14) and the hot water tank (15) are connected in parallel. The opening of the regulating valve is adjusted to adjust the flow rate of the fluid flowing through the cold storage heat exchanger (14) and the hot water tank (15).

10. The single-pump driven phase-change cold storage laser thermal management system as described in claim 9, characterized in that, In the liquid supply unit, under cold storage mode, the refrigerant flowing from the circulation pump flows into the plate heat exchanger after passing through the filter and the four-way reversing valve. After being cooled by the refrigeration cycle, it flows into the cold storage heat exchanger and stores the cold energy. Then, it flows back into the circulation pump through the four-way reversing valve to complete the circulation. Under liquid supply mode, the refrigerant flows into the cold storage heat exchanger and the hot water tank first after passing through the circulation pump and the filter and then through the four-way reversing valve after changing direction. It carries away the cold energy stored in the cold storage heat exchanger and then flows through the load unit. In the load unit, it completes heat exchange to balance the heat generated by the load unit. Then, it flows into the circulation pump through the four-way reversing valve to complete the circulation.

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