A test bench for testing heat storage performance of an immersed phase change thermal storage device and a test method thereof

Abstract

This invention provides a test bench and method for testing the heat storage and release performance of an immersion phase change thermal energy storage device, belonging to the field of thermal energy storage technology. The test bench includes a heat release pipeline, a heat storage pipeline, data acquisition and control equipment, and the thermal energy storage device. Both the heat release pipeline and the heat storage pipeline are connected to both ends of the thermal energy storage device. The heat release pipeline uses a first fluid pump and a proportional three-way valve to regulate the fluid flow rate and temperature to test the heat release performance of the thermal energy storage device under different loads. The heat storage pipeline is equipped with heating units of different heat source types to test the thermal energy storage performance of the thermal energy storage device under different heat source inputs. Three-way valves are connected to the inlet and outlet sides of the thermal energy storage device to switch between the heat release pipeline and the heat storage pipeline. The data acquisition and control equipment can collect the fluid temperature and flow rate of each pipeline and control various actuators. This test bench can perform tests under both heat release and heat storage conditions, featuring a wide range of test conditions and numerous operating parameters, providing a reliable platform for the optimized design and verification of thermal energy storage devices.

Description

Technical Field

[0001] This invention relates to the field of thermal energy storage technology, specifically to a test bench and test method for the thermal energy storage and release performance of an immersion phase change thermal energy storage device. Background Technology

[0002] Latent heat storage technology has advantages such as high heat storage density and relatively stable temperature during the heat storage process, and has good application prospects in building heating, domestic hot water, and industrial waste heat recovery. Submerged heat storage devices have a large heat exchange area, and their internal structure can be adjusted according to different operating conditions, thereby effectively utilizing the latent heat of phase change materials.

[0003] Existing thermal energy storage testing equipment often focuses on testing a single thermal storage process, typically only setting up a thermal storage-side loop, making it difficult to simultaneously test both thermal storage and heat release performance. Especially under heat release conditions, existing testing equipment often neglects demand-side simulation, only testing the fluid output from the thermal energy storage unit. Therefore, there are still discrepancies between the test results and actual heating scenarios.

[0004] Furthermore, existing test devices typically employ a limited range of heat storage methods, often using a single fluid heat source or electric heating, making it difficult to achieve diverse heat storage approaches. Additionally, current heat storage modules are generally designed and manufactured using a single series or parallel flow configuration, which hinders the study of the impact of different flow patterns on heat storage and release performance. Therefore, it is necessary to implement more flexible flow configurations to broaden the operational boundaries of heat storage modules.

[0005] In summary, it is necessary to provide a test bench and test method that can simultaneously test the heat storage and release performance, simulate real demand conditions, and adapt to multiple heat storage sources, thereby providing reliable support for the design optimization and performance verification of thermal storage devices and promoting the deep adaptation of thermal storage devices to actual heat use scenarios. Summary of the Invention

[0006] In view of this, the present invention designs a test bench and its test method capable of simultaneously testing heat storage and release performance, simulating demand-side temperature and flow requirements, and having multiple heat storage forms, as well as an immersion phase change thermal energy storage device with a novel structure. The technical solution is as follows: A test bench for the heat storage and release performance of an immersion phase change thermal energy storage device includes a heat release pipeline, a heat storage pipeline, a phase change thermal energy storage device, and data acquisition and control equipment. The phase change thermal energy storage device contains a phase change material. The heat release pipeline includes a fluid source, a first fluid pump, a proportional three-way valve, and a three-way pipe. The fluid source is connected to the inlet of the proportional three-way valve via the first fluid pump. The first outlet of the proportional three-way valve is connected to the first inlet of the three-way pipe via a first pipeline. The second outlet of the proportional three-way valve is connected to the second inlet of the three-way pipe via a second pipeline, wherein the second pipeline passes through the phase change thermal storage device. The three-way pipe is used to combine the fluids from the first pipeline and the second pipeline, and its outlet is connected to the demand side. The first fluid pump is used to adjust the total flow rate of the heat release pipeline according to the demand side load, and the proportional three-way valve is used to adjust the flow rate ratio distributed to the first pipeline and the second pipeline according to the demand side load, so as to test the heat release performance of the phase change thermal storage device under different demand side loads. The thermal storage pipeline includes a second fluid pump and a heating module. The thermal storage pipeline is connected to the phase change thermal storage device to form a loop. The heating module includes multiple heating units connected in series and using different heat source forms. One or more heating units are selected to heat the fluid in the thermal storage pipeline according to the test requirements, so as to test the thermal storage performance of the phase change thermal storage device under different heat source inputs. The data acquisition and control equipment is used to control the opening and closing of the heat release pipeline and the heat storage pipeline. It selects the heating unit as needed or adjusts the first fluid pump and the proportional three-way valve according to the demand load, and collects the fluid flow rate and temperature of each pipeline in real time.

[0007] Furthermore, the heating module includes a fluid heat source plate heat exchanger, a heat pump circulation plate heat exchanger, and a tee connector connected in series.

[0008] Furthermore, the heat pump circulating plate heat exchanger is connected to a heating side, which includes an expansion valve, a tube-fin evaporator, a plate evaporator, and a compressor. The outlet of the heat pump circulating plate heat exchanger, the expansion valve, the tube-fin evaporator, the compressor, and the inlet of the heat pump circulating plate heat exchanger are sequentially connected to form a first heat pump circulating loop. The outlet of the heat pump circulating plate heat exchanger, the expansion valve, the plate evaporator, the compressor, and the inlet of the heat pump circulating plate heat exchanger are sequentially connected to form a second heat pump circulating loop. When the external heat source is a gaseous heat source, the first heat pump circulating loop is activated and the second heat pump circulating loop is closed. When the external heat source is a fluid heat source, the first heat pump circulating loop is closed and the second heat pump circulating loop is activated.

[0009] Furthermore, the fluid heat source plate heat exchanger is used to heat the fluid in the heat storage pipeline using a fluid heat source; the socket end of the tee is equipped with a heater for directly heating the fluid in the heat storage pipeline.

[0010] Furthermore, the phase change thermal storage device includes a thermal storage device shell and a phase change module; the thermal storage device shell is a rectangular shell with an inlet at the bottom and an outlet at the top, with the inlet and outlet located on opposite sides; the phase change module includes a phase change material enclosure structure and phase change material filled inside the phase change material enclosure structure, the phase change material enclosure structure is fixedly installed inside the thermal storage device by welding or magnetic attraction, and internal flow channels for fluid to flow through are formed between the phase change material enclosure structures.

[0011] Furthermore, along the fluid flow direction inside the phase change heat storage device, the melting point of the phase change materials filled in each phase change material enclosure structure is distributed in a gradient decreasing manner, so that when the heat storage circuit is turned on, the fluid temperature at each location inside the phase change heat storage device is higher than the melting point of the phase change material at the corresponding location, thus shortening the melting time.

[0012] Furthermore, rotatable baffles are alternately installed on the inner wall surfaces of the heat storage tank shells on both sides of the phase change material enclosure structure. The rotatable baffle corresponding to the phase change material enclosure structure near the phase change heat storage tank inlet is located on the inner wall surface of the heat storage tank shell on the inlet side, and the rotatable baffle corresponding to the phase change material enclosure structure near the phase change heat storage tank outlet is located on the inner wall surface of the heat storage tank shell on the outlet side. The rotatable baffles are communicatively connected to the data acquisition and control equipment. Under the control of the data acquisition and control equipment, the rotatable baffles can switch between an open position and a closed position: when in the closed position, there is no gap between the rotatable baffle and the phase change material enclosure structure, and the internal flow channel is a single flow channel; when in the open position, there is a gap between the rotatable baffle and the phase change material enclosure structure, and the internal flow channel is a multi-flow channel.

[0013] Furthermore, the inlet and outlet of the phase change thermal energy storage device are respectively equipped with an outlet-side three-way valve and an inlet-side three-way valve; the second outlet of the proportional three-way valve is connected to the first inlet of the inlet-side three-way valve, and the second inlet of the three-way pipe is connected to the first outlet of the outlet-side three-way valve; the second fluid pump is connected to the second inlet of the inlet-side three-way valve, and the heating module is connected to the second outlet of the outlet-side three-way valve.

[0014] The present invention also provides a method for testing the heat storage and release performance based on the aforementioned test bench, the method comprising testing the heat storage performance and testing the heat release performance; 1) Under thermal storage conditions, perform the following operations: The data acquisition and control equipment controls the closing of the heat release pipeline and the opening of the heat storage pipeline; according to the heating conditions, one or more heating units in the heating module are selected. The heating unit heats the fluid in the heat storage pipeline. The heated fluid flows into the phase change heat storage device to exchange heat with the phase change material and flows out from the outlet of the heat storage device, and then enters the heating module again for circulation. 2) Under exothermic conditions, perform the following operations: The data acquisition and control equipment controls the opening of the heat release pipeline and the closing of the heat storage pipeline. The data acquisition and control equipment adjusts the speed of the first fluid pump and the opening of the proportional three-way valve according to the target flow and temperature at the demand end, thereby adjusting the total flow of the heat release pipeline and the ratio of the fluid flow into the first pipeline and the second pipeline. The low-temperature fluid in the first pipeline flows directly to the three-way valve, and the fluid in the second pipeline flows through the phase change heat storage device and exchanges heat with the phase change material before being converted into a high-temperature fluid and flowing to the three-way valve. The low-temperature fluid and the high-temperature fluid merge at the three-way valve and flow into the third pipeline to reach the demand end. During the heat storage and release process, the data acquisition and control equipment acquires the fluid flow rate of the heat storage pipeline or the second pipeline, the fluid temperature at the inlet and outlet of the phase change heat storage device, the internal fluid temperature of the phase change heat storage device, and the temperature of the phase change material in real time, so as to analyze and obtain the heat storage and release performance of the phase change heat storage device.

[0015] Furthermore, the heat storage and release performance of the phase change thermal storage device includes the heat exchange power and heat exchange capacity of the phase change thermal storage device, the liquid phase distribution and phase change time within the phase change thermal storage device, and the temperature uniformity inside the phase change thermal storage device. The heat exchange power P is: ; In the formula, C p T is the specific heat capacity at constant pressure of the fluid. out T represents the fluid temperature at the outlet of the phase change thermal storage device. in M represents the fluid temperature at the inlet of the phase change thermal storage unit; M represents the fluid flow rate in the thermal storage pipeline under thermal storage conditions and the fluid flow rate in the second pipeline under heat release conditions. The heat exchange capacity Q of the phase change thermal energy storage device is: ; The liquid phase distribution analysis method of phase change thermal energy storage is as follows: linear interpolation is performed on the temperature of each phase change material to calculate the temperature field distribution inside the phase change thermal energy storage. The temperature of the phase change material is higher than the melting point of the phase change material and the temperature is lower than the melting point of the phase change material, which is then converted into liquid phase distribution. The phase change time of a phase change thermal energy storage device refers to the time it takes for all phase change materials to completely change from a solid phase to a liquid phase under thermal storage conditions, and the time it takes for all phase change materials to completely change from a liquid phase to a solid phase under thermal release conditions. The internal temperature uniformity of a phase change thermal storage device is judged by calculating the standard deviation of the temperature of each phase change material.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention enables the performance testing of thermal storage devices under both heat release and heat storage conditions on the same test bench, reducing the time consumption and operational inconvenience caused by moving the thermal storage device during multi-condition testing. In practical applications of thermal storage devices, it is usually necessary to test the performance of heat storage and heat release conditions separately. When switching conditions, the data acquisition and control equipment of the present invention can quickly complete the switching between heat release and heat storage conditions by opening and closing the various interfaces of the three-way valve on the inlet side and the three-way valve on the outlet side of the thermal storage device, thereby improving the continuity and convenience of the testing process.

[0017] (2) Under exothermic conditions, this invention can simulate real demand requirements and achieve the target fluid flow rate and target fluid temperature. The data acquisition and control equipment can adjust the opening of the proportional three-way valve according to the temperature and flow rate of the mixed fluid to change the flow ratio of the fluid in the first pipeline and the low-temperature pipeline, so that the mixed fluid reaches the target temperature; at the same time, the data acquisition and control equipment can adjust the speed of the first fluid pump to make the mixed fluid reach the target flow rate. Therefore, this invention can more closely approximate the temperature and flow requirements of real demand and test the exothermic performance of the phase change thermal storage device under different demand loads.

[0018] (3) The present invention can realize multiple heat storage sources under heat storage conditions. The heat storage pipeline includes fluid heat storage mode, heat pump heat storage mode and electric heat storage mode; the data acquisition and control equipment can control the gas expansion valve, fluid expansion valve and heater to enable the fluid in the heat storage pipeline to obtain heat in different heat storage modes, thereby simulating different heat storage scenarios and reducing the limitation of single heat source heat storage on the performance test of phase change heat storage device.

[0019] (4) The submerged phase change thermal energy storage device of the present invention can realize modular installation of the phase change material enclosure structure and can switch between series mode and parallel mode. The phase change material enclosure structure can be installed inside the submerged thermal energy storage device shell by welding or magnetic connection, which facilitates quick replacement of modules or adjustment of module spacing; at the same time, the data acquisition and control equipment can switch the flow channel inside the thermal energy storage device shell between single flow channel and multi-flow channel by controlling the position of the rotatable baffle, thereby meeting the thermal energy storage and release performance testing requirements under different flow forms and different phase change material enclosure structure arrangements. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a test bench for the heat storage and release of an immersion thermal accumulator. Figure 2 This is a diagram showing the serial numbers of the three-way valve and three-way pipe interfaces on the immersion thermal storage and release test bench; Figure 3 This is a schematic diagram of a test bench for the heat release condition of an immersion thermal storage device. Figure 4 This is a schematic diagram of a test bench for the thermal storage conditions of an immersion thermal storage device. Figure 5 This is a schematic diagram of a test bench for fluid thermal storage mode of immersion thermal storage. Figure 6 This is a schematic diagram of a test bench for heat pump storage mode under immersion thermal storage conditions. Figure 7 This is a schematic diagram of a test bench for the electric thermal storage mode of an immersion thermal storage device. Figure 8 This is a schematic diagram of a submerged thermal storage unit in series. Figure 9 This is a schematic diagram of a parallel mode of submerged thermal storage.

[0021] Among them, 1—heat release pipeline, 101—tee pipe, 102—medium temperature fluid flow meter for heat release pipeline, 103—low temperature fluid temperature sensor for heat release pipeline, 104—medium temperature fluid temperature sensor for heat release pipeline, 105—demand side, 106—low temperature fluid flow meter for heat release pipeline, 107—proportional three-way valve, 108—fluid source, 109—first fluid pump, 110—high temperature fluid flow meter for heat release pipeline, 2—heat storage pipeline, 21—fluid heat source plate heat exchanger, 22—heat pump circulation plate heat exchanger, 23—tee connector, 24—second fluid pump, 25—fluid flow meter for heat storage pipeline, 3— Heating side, 31—expansion valve, 32—tube-fin evaporator, 33—plate evaporator, 34—compressor, 35—heater, 4—immersion phase change thermal storage, 401—three-way valve on the outlet side of thermal storage, 402—three-way valve on the inlet side of thermal storage, 403—fluid temperature sensor at the outlet of thermal storage, 404—fluid temperature sensor inside thermal storage, 405—phase change material temperature sensor in thermal storage, 406—fluid temperature sensor at the inlet of thermal storage, 407—rotatable baffle, 408—thermal storage shell, 409—phase change material enclosure structure, 410—phase change material, 5—data acquisition and control equipment. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] Example 1 As attached Figure 1 As shown, this embodiment provides a specific example of a test bench for the heat storage and release performance of a submerged phase change thermal energy storage device. The system includes a heat release pipeline 1, a heat storage pipeline 2, a heating side 3, a submerged phase change thermal energy storage device 4, and a data acquisition and control device 5. The inlet of the submerged phase change thermal energy storage device 4 is connected to a three-way valve 402 on the inlet side of the thermal energy storage device, and the outlet of the submerged phase change thermal energy storage device 4 is connected to a three-way valve 401 on the outlet side of the thermal energy storage device.

[0024] First, the submerged phase change thermal energy storage device 4 tested in this embodiment will be described: as shown in the attached document. Figure 8 and attached Figure 9As shown, the submerged phase change thermal energy storage device 4 includes a storage device shell 408 and multiple horizontally parallel phase change material enclosure structures 409 inside. The storage device shell 408 is a rectangular shell with an inlet at the bottom and an outlet at the top, located on opposite sides. The phase change material enclosure structures 409 are filled with phase change material 410, which is used to fix the phase change material 410. The phase change material 410 is used to exchange heat with the fluid inside the submerged phase change thermal energy storage device 4, thereby absorbing and storing a large amount of latent heat during melting and releasing the stored heat during solidification. To further improve the heat storage and release performance of the storage device, different phase change material enclosure structures 409 can be filled with phase change materials 410 with different melting points, so that the fluid temperature at each location inside the submerged phase change thermal energy storage device 4 is higher than the melting point of the corresponding phase change material 410 under thermal storage conditions, thereby causing the phase change material 410 to completely melt and fully utilize the latent heat. As a specific implementation, phase change materials with gradually decreasing melting points can be filled into the phase change material enclosure structure 409 along the fluid flow direction in the submerged phase change thermal storage tank 4, thereby shortening the melting time. Rotatable baffles 407 are installed on the inner wall surface of the storage tank shell 408 near the inlet of the submerged phase change thermal storage tank 4 on the bottom phase change material enclosure structure 409, and on the inner wall surface of the storage tank shell 408 near the outlet of the submerged phase change thermal storage tank 4 on the top phase change material enclosure structure 409. Other rotatable baffles 407 are alternately installed on the inner wall surfaces of the storage tank shell 408 on both sides of the middle phase change material enclosure structure 409. The rotatable baffles 407 can be switched between an open position and a closed position: when in the closed position, the rotatable baffle 407 is horizontal, such as... Figure 8 There is no gap between it and the phase change material enclosure structure 409. At this time, the submersible phase change heat storage device 4 is in series mode, and the internal flow channel of the heat storage device shell 408 is a single flow channel. In this mode, the flow channel is long, and the fluid inside the heat storage device shell 408 can fully exchange heat with the phase change material 410, so that the two temperatures are as close as possible, thereby ensuring a high heat utilization rate; when in the open position, the baffle 407 can be rotated vertically, such as Figure 9 There is a gap between it and the phase change material enclosure structure 409. The internal flow channel of the heat storage tank shell 408 is a multi-channel flow channel. In this mode, the flow resistance is low and a large flow rate can be allowed to pass through. At the same time, the phase change material 410 in each phase change material enclosure structure 409 can exchange heat with the fluid inside the heat storage tank shell 408 simultaneously. The heat transfer rate is fast, realizing rapid heat storage and release. The series mode and parallel mode can flexibly change the flow topology structure by rotating the rotatable baffle 407 according to different application scenarios, thereby meeting the needs of different working conditions and the heat storage and release performance test requirements under different flow forms and different phase change material enclosure structure arrangements.

[0025] The phase change material enclosure structure 409 can be installed inside the submerged phase change thermal storage tank shell 408 by welding or magnetic connection. Preferably, when it is necessary to quickly replace modules (i.e., modules composed of the phase change material enclosure structure 409 and the phase change material 410 inside it) or adjust the module spacing, a magnetic connection can be used to adjust the spacing of the phase change material enclosure structure 409 or to replace the phase change material enclosure structure 409. When it is necessary to improve structural stability or long-term operational reliability, a welding method can be used. Furthermore, the placement of the phase change material enclosure structure 409 inside the thermal storage tank shell 408 is not limited to being attached. Figure 8 and attached Figure 9 The horizontal placement shown can be reasonably arranged according to the internal space of the heat storage tank shell 408, such as vertical placement.

[0026] As attached Figure 8 As shown, an outlet fluid temperature sensor 403 is installed at the outlet of the submerged phase change thermal storage unit 4 to collect the fluid temperature at the outlet of the submerged phase change thermal storage unit 4; an inlet fluid temperature sensor 406 is installed at the inlet of the submerged phase change thermal storage unit 4 to collect the fluid temperature at the inlet of the submerged phase change thermal storage unit 4; an internal fluid temperature sensor 404 is installed in the internal flow channel of the submerged phase change thermal storage unit 4 to collect the fluid temperature in the internal flow channel of the submerged phase change thermal storage unit 4; and a phase change material temperature sensor 405 is installed in the phase change material 410 inside the submerged phase change thermal storage unit 4 to collect the temperature of the phase change material 410. The outlet fluid temperature sensor 403, the internal fluid temperature sensor 404, the phase change material temperature sensor 405, the inlet fluid temperature sensor 406, and the rotatable baffle 407 can all be adjusted according to the position of the phase change material enclosure structure 409.

[0027] As attached Figure 3 As shown, the heat release pipeline 1 includes a three-way pipe 101, a medium-temperature fluid flow meter 102, a low-temperature fluid temperature sensor 103, a medium-temperature fluid temperature sensor 104, a demand end 105, a low-temperature fluid flow meter 106, a proportional three-way valve 107, a fluid source 108, a first fluid pump 109, and a high-temperature fluid flow meter 110. (See attached...) Figure 2The interface numbers of the three-way pipe 101, the proportional three-way valve 107, the heat storage outlet side three-way valve 401, and the heat storage inlet side three-way valve 402 are indicated. The inlet of the submerged phase change heat storage 4 is connected to the inlet of the heat storage inlet side three-way valve 402, and the outlet of the submerged phase change heat storage 4 is connected to the second inlet of the heat storage outlet side three-way valve 401. The inlets of the fluid source 108, the first fluid pump 109, and the proportional three-way valve 107 are connected in sequence. The fluid source 108 is used to provide low-temperature fluid to the heat release pipeline 1, and the first fluid pump 109 pumps the fluid into the heat release pipeline 1 and controls the total flow rate. The heat release pipeline 1 is divided into a first pipeline, a second pipeline, and a third pipeline. The first pipeline is formed by sequentially connecting the first outlet of the proportional three-way valve 107, the low-temperature fluid flow meter 106 of the heat release pipeline, the low-temperature fluid temperature sensor 103 of the heat release pipeline, and the first inlet of the three-way valve 101. The low-temperature fluid flow meter 106 and the low-temperature fluid temperature sensor 103 of the heat release pipeline are used to collect the flow rate and fluid temperature of the first pipeline, respectively. The second pipeline is first formed by sequentially connecting the second outlet of the proportional three-way valve 107, the high-temperature fluid flow meter 110 of the heat release pipeline, and the first inlet of the three-way valve 402 on the inlet side of the heat storage tank. Then, the outlet of the three-way valve 402 on the inlet side of the heat storage tank is connected to the inlet of the heat storage tank shell 408, and the outlet of the heat storage tank shell 408 is connected to the inlet of the three-way valve 401 on the outlet side of the heat storage tank. Finally, the outlet of the three-way valve 401 on the outlet side of the heat storage tank... The second outlet is connected to the second inlet of the three-way pipe 101. The high-temperature fluid flow meter 110 of the heat release pipeline is used to collect the flow rate of the second pipeline. The proportional three-way valve 107 is used to simultaneously distribute the low-temperature fluid provided by the fluid source 108 to the first pipeline and the second pipeline, and adjust the flow ratio of the first pipeline and the second pipeline by changing the opening degree. The third pipeline is composed of the outlet of the three-way pipe 101, the medium-temperature fluid flow meter 102 of the heat release pipeline, the medium-temperature fluid temperature sensor 104 of the heat release pipeline, and the demand end 105 connected in sequence. The medium-temperature fluid flow meter 102 and the medium-temperature fluid temperature sensor 104 of the heat release pipeline are used to collect the flow rate and fluid temperature of the first pipeline, respectively. The demand end 105 is used to simulate the actual heat-using terminal, which can be the building heating end, the domestic hot water end, the industrial heat exchange end, or other load ends that require stable temperature and flow supply.

[0028] As attached Figure 4As shown, the thermal storage pipeline 2 includes a fluid heat source plate heat exchanger 21, a heat pump circulation plate heat exchanger 22, a three-way connector 23, a second fluid pump 24, and a thermal storage pipeline fluid flow meter 25. The fluid heat source plate heat exchanger 21 is used to heat the fluid in the thermal storage pipeline 2 using a fluid heat source. The heat pump circulation plate heat exchanger 22 is connected to a heating side 3 and heats the fluid in the thermal storage pipeline 2 through the heating side 3. A heater 35 is installed at the socket end of the three-way connector 23 for directly heating the fluid in the thermal storage pipeline 2. Different heating methods can be selected as needed to heat the fluid in the thermal storage pipeline 2, thereby testing the thermal storage performance of the thermal storage device under different heat source inputs. The thermal storage pipeline 2 is first connected in sequence to the second outlet of the thermal storage outlet side three-way valve 401, the fluid heat source plate heat exchanger 21, the heat pump circulation plate heat exchanger 22, and the inlet of the three-way connector 23. Then, the outlet of the three-way connector 23, the second fluid pump 24, the thermal storage pipeline fluid flow meter 25, and the second inlet of the thermal storage inlet side three-way valve 402 are connected in sequence. Finally, the outlet of the thermal storage inlet side three-way valve 402 is connected to the inlet of the thermal storage shell 408, and the outlet of the thermal storage shell 408 is connected to the inlet of the thermal storage outlet side three-way valve 401, forming a closed loop. The second fluid pump 24 is used to drive the fluid circulation in the thermal storage pipeline 2, and the thermal storage pipeline fluid flow meter 25 is used to collect the flow rate in the thermal storage pipeline 2.

[0029] As attached Figure 4 As shown, the heating side 3 includes an expansion valve 31, a tube-fin evaporator 32, a plate evaporator 33, a compressor 34, and a heater 35; the heating side 3 includes a heat pump circulation loop; when the external heat source is a gaseous heat source, the heat pump circulation plate heat exchanger 22, expansion valve 31, tube-fin evaporator 32, and compressor 34 are connected end-to-end in sequence to form a first heat pump circulation loop; when the external heat source is a fluid heat source, the heat pump circulation plate heat exchanger 22, expansion valve 31, plate evaporator 33, and compressor 34 are connected end-to-end in sequence to form a second heat pump circulation loop. The heat pump circulation loop includes an expansion valve 31 for reducing the pressure of the working fluid within the heat pump circulation loop; a tube-finned evaporator 32 for absorbing heat from an external gaseous heat source; a plate evaporator 33 for absorbing heat from an external fluid heat source; and a compressor 34 for driving the working fluid within the heat pump circulation loop. When the working fluid in the heat pump circulation loop is a gas, the compressor 34 further compresses it into a high-temperature, high-pressure gas. The high-temperature working fluid in the heat pump circulation exchanges heat with the low-temperature fluid in the heat storage pipeline 2 at the heat pump circulation plate heat exchanger 22, converting it into a high-temperature fluid.

[0030] The data acquisition and control device 5 is communicatively connected to various temperature sensors and flow meters, and can collect fluid temperature and flow data of the heat release pipeline 1 and the heat storage pipeline 2, as well as fluid temperature and phase change material temperature data at the inlet, outlet, and inside of the submerged phase change heat storage device 4. At the same time, the data acquisition and control device 5 is also communicatively connected to various valves, pumps, heaters 35, and rotatable baffles 407, and can control the proportional three-way valve 107, the first fluid pump 109, the second fluid pump 24, the expansion valve 31, the heater 35, the heat storage device outlet side three-way valve 401, the heat storage device inlet side three-way valve 402, and the rotatable baffle 407 according to different operating conditions or flow and temperature requirements.

[0031] The following describes the heat release and heat storage conditions of the immersion phase change thermal energy storage performance test bench described in this embodiment: 1) Exothermic operating conditions As attached Figure 3 As shown, the first fluid pump 109 pumps the cryogenic fluid from the fluid source 108 to the inlet of the proportional three-way valve 107; in the first pipeline, the cryogenic fluid first flows out from the first outlet of the proportional three-way valve 107, and the cryogenic fluid flow meter 106 and the cryogenic fluid temperature sensor 103 in the heat release pipeline monitor the flow rate and temperature data of the cryogenic fluid, finally flowing to the first inlet of the three-way pipe 101; in the second pipeline, the fluid first flows out from the second outlet of the proportional three-way valve 107, and the high-temperature fluid flow meter 110 in the heat release pipeline monitors the fluid flow rate data, then the fluid flows through the first inlet and outlet of the three-way valve 402 on the inlet side of the heat storage tank, and subsequently, the fluid... The fluid flows into the submerged phase change thermal storage unit 4, flows in the flow channel formed by the phase change material enclosure structure 409, and is heated by the phase change material 410 to become a high-temperature fluid. Then it flows through the inlet and first outlet of the three-way valve 401 on the outlet side of the thermal storage unit, and finally flows into the second inlet of the three-way pipe 101. The medium-temperature fluid in the third pipeline is obtained by mixing the low-temperature fluid at the first inlet and the high-temperature fluid at the second inlet of the three-way pipe 101. First, the medium-temperature fluid flows out from the outlet of the three-way pipe 101. The medium-temperature fluid flow meter 102 and the medium-temperature fluid temperature sensor 104 in the heat release pipeline monitor the flow rate and temperature data of the medium-temperature fluid. Finally, the medium-temperature fluid flows into the demand side 105. The aforementioned medium-temperature fluid can be used to meet the flow and temperature requirements of demand side 105. Based on the target medium-temperature fluid temperature and flow rate required by demand side 105, the data acquisition and control device 5 collects the medium-temperature fluid temperature and flow rate monitored by the medium-temperature fluid temperature sensor 104 and the medium-temperature fluid flow meter 102 in the heat release pipeline. It controls the rotation speed of the first fluid pump 109 to achieve the target medium-temperature fluid flow rate and controls the opening degree of the proportional three-way valve 107 to achieve the target medium-temperature fluid temperature. Specifically, when the monitored medium-temperature fluid temperature is lower than the target medium-temperature fluid temperature, the data acquisition and control device 5 controls the proportional three-way valve 107 to increase the opening degree of the second pipeline and decrease the opening degree of the first pipeline; when the monitored medium-temperature fluid temperature is higher than the target medium-temperature fluid temperature, the data acquisition and control device 5 controls the proportional three-way valve 107 to decrease the opening degree of the second pipeline and increase the opening degree of the first pipeline.

[0032] 2) Thermal storage conditions As attached Figure 4 As shown, the second fluid pump 24 first pumps the heated high-temperature fluid, and the heat storage pipeline fluid flow meter 25 monitors the flow data of the high-temperature fluid. Then, the high-temperature fluid flows into the submerged phase change heat storage tank 4 after passing through the second inlet and outlet of the three-way valve 402 on the inlet side of the heat storage tank. The high-temperature fluid flows in the flow channel formed by the phase change material enclosure structure 409 and heats the phase change material 410 to become a low-temperature fluid. Finally, the low-temperature fluid flows through the inlet and second outlet of the three-way valve 401 on the outlet side of the heat storage tank and is reheated to become a high-temperature fluid. Preferably, the thermal storage pipeline 2 includes fluid thermal storage mode, heat pump thermal storage mode, and electric thermal storage mode: ① Fluid thermal storage mode As attached Figure 5 As shown, the external fluid heat source directly supplies heat to the low-temperature fluid in the heat storage pipeline 2 through the fluid heat source plate heat exchanger 21, while the fluid in the heat storage pipeline 2 flows directly through the heat pump circulation plate heat exchanger 22 and the three-way joint 23 without heat exchange occurring inside it. ② Heat pump thermal storage mode As attached Figure 6 As shown, when the external heat source is a gaseous heat source, the gaseous heat source flows through the tube-fin evaporator 32; when the external heat source is a fluid heat source, the fluid heat source flows through the plate evaporator 33. The working fluid in the heat pump circulation loop absorbs heat from the external heat source and, after passing through the heat pump circulation, heats the low-temperature fluid inside the heat storage pipeline 2 at the heat pump circulation plate heat exchanger 22. The fluid inside the heat storage pipeline 2 flows directly through the fluid heat source plate heat exchanger 21 and the three-way joint 23 without undergoing heat exchange inside it. ③ Electric thermal storage mode As attached Figure 7As shown, the data acquisition and control equipment 5 controls the heating amount of the fluid in the heat storage pipeline 2 in real time through the heater 35 to simulate a specific heat source form. At the same time, the fluid in the heat storage pipeline 2 flows directly through the fluid heat source plate heat exchanger 21 and the heat pump circulation plate heat exchanger 22, and does not undergo heat exchange inside them. The data acquisition and control device 5 can open and close various interfaces of the inlet-side three-way valve 402 and the outlet-side three-way valve 401 of the thermal storage unit according to the operating conditions. When the test bench is in heat release condition, it controls the first inlet and outlet of the inlet-side three-way valve 402 of the thermal storage unit to open and the second inlet to close, and controls the inlet and first outlet of the outlet-side three-way valve 401 of the thermal storage unit to open and the second outlet to close. When the test bench is in heat storage condition, it controls the second inlet and outlet of the inlet-side three-way valve 402 of the thermal storage unit to open and the first inlet to close, and controls the inlet and second outlet of the outlet-side three-way valve 401 of the thermal storage unit to open and the first outlet to close.

[0033] Example 2 This embodiment further provides a test method for the above-mentioned submerged phase change thermal energy storage device 4. This method is based on the submerged phase change thermal energy storage device heat storage and release performance test bench described in Embodiment 1. The performance test of the submerged phase change thermal energy storage device 4 mainly includes the measurement of heat exchange power and heat exchange, the measurement of phase change time and liquid phase distribution, and the evaluation of temperature uniformity. The test method is as follows: First, connect the inlet of the submerged phase change thermal storage unit 4 to the outlet of the inlet-side three-way valve 402, and connect the outlet of the submerged phase change thermal storage unit 4 to the inlet of the outlet-side three-way valve 401. Next, arrange the data measurement points (i.e., temperature sensors) inside the submerged phase change thermal storage unit 4, and ensure they are connected to the data acquisition and control equipment 5. Finally, select the operating condition on the data acquisition and control equipment 5. The test methods for the two operating conditions, heat storage and heat release, are described below: 1) Thermal storage conditions First, select the thermal storage condition in the data acquisition and control device 5. The data acquisition and control device 5 controls the second inlet and outlet of the three-way valve 402 on the inlet side of the thermal storage tank to open, and the first inlet to close. It also controls the inlet and second outlet of the three-way valve 401 on the outlet side of the thermal storage tank to open, and the first outlet to close, thus activating the fluid flow meter 25 in the thermal storage pipeline. Next, select the thermal storage mode for the thermal storage pipeline in the data acquisition and control device 5. When the fluid heat storage mode is selected, the data acquisition and control device 5 closes the expansion valve 31 and the heater 35, and the external fluid heat source will flow directly through the fluid heat source plate heat exchanger 21 to transfer heat to the fluid in the heat storage pipeline 2. When the heat pump storage mode is selected, if the external heat source is gas, the data acquisition and control device 5 opens the expansion valve 31 and the tube-fin evaporator 32 and closes the plate evaporator 33 and the heater 35; if the external heat source is fluid, the data acquisition and control device 5 closes the tube-fin evaporator 32 and the heater 35 and opens the expansion valve 31 and the plate evaporator 33; the working fluid in the heat pump circulation pipeline transfers heat to the fluid in the heat storage pipeline 2 through the heat pump circulation plate heat exchanger 22. When the electric thermal storage mode is selected, the data acquisition and control device 5 closes the expansion valve 31, the tube-fin evaporator 32 and the plate evaporator 33, and turns on the heater 35. The heater 35 transfers heat to the fluid in the thermal storage pipeline 2 at the three-way joint 23. Finally, the data acquisition and control device 5 starts the second fluid pump 24. The second fluid pump 24 pumps high-temperature fluid through the second inlet and outlet of the three-way valve 402 on the inlet side of the heat storage tank and then into the submerged phase change heat storage tank 4. The high-temperature fluid flows in the flow channel formed by the phase change material enclosure structure 409 and heats the phase change material 410 to become a low-temperature fluid. Finally, the low-temperature fluid flows through the inlet and second outlet of the three-way valve 401 on the outlet side of the heat storage tank and flows back to the heating side 3. During this process, the heat storage pipeline fluid flow meter 25 collects the flow rate of the heat storage pipeline 2 in real time, the heat storage tank outlet fluid temperature sensor 403 collects the fluid temperature at the outlet of the submerged phase change heat storage tank 4 in real time, the heat storage tank inlet fluid temperature sensor 406 collects the fluid temperature at the inlet of the submerged phase change heat storage tank 4 in real time, the heat storage tank internal fluid temperature sensor 404 collects the fluid temperature in the internal flow channel of the submerged phase change heat storage tank 4 in real time, and the heat storage tank phase change material temperature sensor 405 collects the temperature of the phase change material 410 in real time.

[0034] When measuring the heat exchange power and heat exchange capacity of the submerged phase change thermal energy storage unit 4, the data acquisition and control equipment 5 receives the fluid temperature T at the outlet of the submerged phase change thermal energy storage unit 4. out The fluid temperature T at the inlet of the submerged phase change thermal energy storage unit 4 in The fluid flow rate M1 and the specific heat capacity C at constant pressure of the heat storage pipeline 2. p Then, the heat exchange power P of the submerged phase change thermal energy storage device 4 at the current moment is: The unit of heat exchange power P is W; the heat exchange capacity Q of the submerged phase change thermal energy storage device 4 is: The unit of heat exchange Q is J; When the submerged phase change thermal energy storage device is in thermal storage mode, both P and Q are positive values.

[0035] When measuring the phase change time and liquid phase distribution of the submerged phase change thermal storage unit 4, linear interpolation is performed on the temperatures measured by the phase change material temperature sensor 405 at each measuring point coordinate to calculate the internal temperature field distribution of the submerged phase change thermal storage unit 4: the region where the temperature of the phase change material 410 is higher than its melting point is the liquid phase region, and the region where the temperature is lower than its melting point is the solid phase region. This allows the temperature field distribution to be further converted into a liquid phase distribution. Under thermal storage conditions, the time it takes for all phase change materials 410 to completely transform from the solid phase to the liquid phase is the phase change time.

[0036] The internal temperature uniformity of the submerged phase change thermal storage device 4 is judged by calculating the standard deviation of different temperatures measured by the phase change material temperature sensor 405 at each measuring point coordinate.

[0037] 2) Exothermic operating conditions First, the heat release condition is selected in the data acquisition and control device 5. The data acquisition and control device 5 controls the first inlet and outlet of the three-way valve 402 on the inlet side of the heat storage tank to open and the second inlet to close. It also controls the inlet and first outlet of the three-way valve 401 on the outlet side of the heat storage tank to open and the second outlet to close. Next, the data acquisition and control device 5 activates all fluid flow meters and fluid temperature sensors in the heat release pipeline 1, as well as the proportional three-way valve 107. Subsequently, the target flow rate and temperature of the demand end 105 are input into the data acquisition and control device 5. The data acquisition and control device 5 activates the first fluid pump 109 and adjusts the speed of the first fluid pump 109 according to the data of the medium-temperature fluid flow meter 102 in the heat release pipeline. It also adjusts the opening degree of the proportional three-way valve 107 for the first and second pipelines according to the data of the medium-temperature fluid temperature sensor 104 in the heat release pipeline.

[0038] When measuring the heat exchange power and heat exchange capacity of the submerged phase change thermal energy storage unit 4, the data acquisition and control equipment 5 receives the fluid temperature T at the outlet of the submerged phase change thermal energy storage unit 4. out The fluid temperature T at the inlet of the submerged phase change thermal energy storage unit 4 in The high-temperature fluid flow meter 110 in the heat release pipeline monitors the fluid flow rate M2 and the fluid's specific heat capacity at constant pressure C. p Then, at the current moment, the heat exchange power P of the submerged phase change thermal energy storage device 4 is: The formula for calculating the heat exchange rate Q is the same as that for the heat storage condition. When the submerged phase change heat storage device 4 is in the heat release condition, P and Q are negative values.

[0039] The phase change time and liquid phase distribution measurement of the submerged phase change thermal storage device 4 are the same as those under thermal storage conditions. Under heat release conditions, the time it takes for all phase change materials to completely change from liquid to solid is the phase change time.

[0040] The internal temperature uniformity of the submerged phase change thermal energy storage device is evaluated in the same way as that under thermal energy storage conditions.

[0041] In both heat release and heat storage tests, the position of the rotatable baffle 407 can be changed by the data acquisition and control equipment 5, thereby meeting the heat storage and release performance test requirements under different flow patterns and different phase change material enclosure structure arrangements.

[0042] The test bench in this embodiment is not limited to the performance testing of submerged phase change thermal energy storage devices. When the submerged phase change thermal energy storage device is replaced with other types of thermal energy storage devices, and its connecting pipes and internal measuring point arrangement are adjusted, the heat release pipe 1, heat storage pipe 2, heating side 3, and data acquisition and control equipment 5 of this invention can also be used to carry out heat storage and release performance testing.

[0043] In summary, this invention provides a test bench and method for the heat release performance of a submerged phase change thermal storage device. By controlling the opening and closing of different interfaces of the three-way valve 402 on the inlet side and the three-way valve 401 on the outlet side of the thermal storage device, the test conditions can be flexibly switched and selected. During the test, temperature sensors and flow meters collect real-time data on the flow rate in the pipeline, the fluid temperature at the inlet and outlet of the submerged phase change thermal storage device 4, the internal fluid temperature of the submerged phase change thermal storage device 4, and the temperature of the phase change material 410, simultaneously achieving the evaluation of multiple heat storage and release performance parameters, thus improving the continuity and convenience of the multi-condition test process.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A test bench for the heat storage and release performance of an immersion phase change thermal energy storage device, characterized in that, It includes heat dissipation pipelines, heat storage pipelines, phase change heat storage devices, and data acquisition and control equipment. The phase change heat storage devices contain phase change materials. The heat release pipeline includes a fluid source, a first fluid pump, a proportional three-way valve, and a three-way pipe; the fluid source is connected to the inlet of the proportional three-way valve via the first fluid pump; the first outlet of the proportional three-way valve is connected to the first inlet of the three-way pipe via the first pipeline; The second outlet of the proportional three-way valve is connected to the second inlet of the three-way pipe through the second pipeline, wherein the second pipeline passes through the phase change thermal storage device; the three-way pipe is used to merge the fluids of the first pipeline and the second pipeline, and its outlet is connected to the demand side; the first fluid pump is used to adjust the total flow rate of the heat release pipeline according to the demand side load, and the proportional three-way valve is used to adjust the flow rate ratio distributed to the first pipeline and the second pipeline according to the demand side load, so as to test the heat release performance of the phase change thermal storage device under different demand side loads; The thermal storage pipeline includes a second fluid pump and a heating module. The thermal storage pipeline is connected to the phase change thermal storage device to form a loop. The heating module includes multiple heating units connected in series and using different heat source forms. One or more heating units are selected to heat the fluid in the thermal storage pipeline according to the test requirements, so as to test the thermal storage performance of the phase change thermal storage device under different heat source inputs. The data acquisition and control equipment is used to control the opening and closing of the heat release pipeline and the heat storage pipeline. It selects the heating unit as needed or adjusts the first fluid pump and the proportional three-way valve according to the demand load, and collects the fluid flow rate and temperature of each pipeline in real time.

2. The test bench according to claim 1, characterized in that, The heating module includes a fluid heat source plate heat exchanger, a heat pump circulation plate heat exchanger, and a three-way connector connected in series.

3. The test stand according to claim 2, characterized in that, The heat pump circulating plate heat exchanger is connected to a heating side, which includes an expansion valve, a tube-fin evaporator, a plate evaporator, and a compressor. The outlet of the heat pump circulating plate heat exchanger, the expansion valve, the tube-fin evaporator, the compressor, and the inlet of the heat pump circulating plate heat exchanger are connected in sequence to form a first heat pump circulating loop. The outlet of the heat pump circulating plate heat exchanger, the expansion valve, the plate evaporator, the compressor, and the inlet of the heat pump circulating plate heat exchanger are connected in sequence to form a second heat pump circulating loop. When the external heat source is a gaseous heat source, the first heat pump circulating loop is activated and the second heat pump circulating loop is closed. When the external heat source is a fluid heat source, the first heat pump circulating loop is closed and the second heat pump circulating loop is activated.

4. The test stand according to claim 2, characterized in that, The fluid heat source plate heat exchanger is used to heat the fluid in the heat storage pipeline using a fluid heat source; the socket end of the tee joint is equipped with a heater for directly heating the fluid in the heat storage pipeline.

5. The test stand according to claim 1, characterized in that, The phase change thermal storage device includes a thermal storage shell and a phase change module; the thermal storage shell is a rectangular shell with an inlet at the bottom and an outlet at the top, with the inlet and outlet located on opposite sides; the phase change module includes a phase change material enclosure structure and phase change material filled inside the phase change material enclosure structure, the phase change material enclosure structure is fixedly installed inside the thermal storage device by welding or magnetic attraction, and internal flow channels for fluid to flow through are formed between the phase change material enclosure structures.

6. The test stand according to claim 5, characterized in that, Along the fluid flow direction inside the phase change heat storage device, the melting point of the phase change material filled in each phase change material enclosure structure is distributed in a gradient decreasing manner, so that when the heat storage circuit is turned on, the fluid temperature at each position inside the phase change heat storage device is higher than the melting point of the phase change material at the corresponding position, thus shortening the melting time.

7. The test stand according to claim 5, characterized in that, Rotatable baffles are alternately installed on the inner walls of the thermal storage tank shells on both sides of the phase change material (PCM) enclosure structure. The rotatable baffle corresponding to the PCM enclosure structure near the PCM inlet is located on the inner wall of the thermal storage tank shell on the PCM inlet side, and the rotatable baffle corresponding to the PCM enclosure structure near the PCM outlet is located on the inner wall of the thermal storage tank shell on the PCM outlet side. The rotatable baffles are communicatively connected to data acquisition and control equipment. Under the control of the data acquisition and control equipment, the rotatable baffles can switch between open and closed positions: when in the closed position, there is no gap between the rotatable baffle and the PCM enclosure structure, and the internal flow channel is a single flow channel; when in the open position, there is a gap between the rotatable baffle and the PCM enclosure structure, and the internal flow channel is a multi-flow channel.

8. The test stand according to claim 5, characterized in that, The phase change thermal energy storage device is equipped with an outlet-side three-way valve and an inlet-side three-way valve at its inlet and outlet, respectively; the second outlet of the proportional three-way valve is connected to the first inlet of the inlet-side three-way valve, and the second inlet of the three-way pipe is connected to the first outlet of the outlet-side three-way valve; the second fluid pump is connected to the second inlet of the inlet-side three-way valve, and the heating module is connected to the second outlet of the outlet-side three-way valve.

9. A method for testing the heat storage and release performance based on the test bench according to any one of claims 1-8, characterized in that, The method includes testing the thermal storage performance and testing the heat release performance; 1) Under thermal storage conditions, perform the following operations: The data acquisition and control equipment controls the closing of the heat release pipeline and the opening of the heat storage pipeline; according to the heating conditions, one or more heating units in the heating module are selected. The heating unit heats the fluid in the heat storage pipeline. The heated fluid flows into the phase change heat storage device to exchange heat with the phase change material and flows out from the outlet of the heat storage device, and then enters the heating module again for circulation. 2) Under exothermic conditions, perform the following operations: The data acquisition and control equipment controls the opening of the heat release pipeline and the closing of the heat storage pipeline; the data acquisition and control equipment adjusts the speed of the first fluid pump and the opening of the proportional three-way valve according to the target flow and temperature at the demand end, thereby adjusting the total flow of the heat release pipeline and the ratio of the fluid flow entering the first pipeline and the second pipeline. The low-temperature fluid in the first pipeline flows directly to the tee pipe. The fluid in the second pipeline flows through the phase change heat storage device and exchanges heat with the phase change material, then is converted into a high-temperature fluid and flows to the tee pipe. The low-temperature fluid and the high-temperature fluid merge at the tee pipe and flow into the third pipeline to reach the demand side. During the heat storage and release process, the data acquisition and control equipment acquires the fluid flow rate of the heat storage pipeline or the second pipeline, the fluid temperature at the inlet and outlet of the phase change heat storage device, the internal fluid temperature of the phase change heat storage device, and the temperature of the phase change material in real time, so as to analyze and obtain the heat storage and release performance of the phase change heat storage device.

10. The method according to claim 9, characterized in that, The heat storage and release performance of the phase change thermal storage device includes the heat exchange power and heat exchange capacity of the phase change thermal storage device, the liquid phase distribution and phase change time in the phase change thermal storage device, and the temperature uniformity inside the phase change thermal storage device. The heat exchange power P is: ； In the formula, C p T is the specific heat capacity at constant pressure of the fluid. out T represents the fluid temperature at the outlet of the phase change thermal storage device. in M represents the fluid temperature at the inlet of the phase change thermal storage unit; M represents the fluid flow rate in the thermal storage pipeline under thermal storage conditions and the fluid flow rate in the second pipeline under heat release conditions. The heat exchange capacity Q of the phase change thermal energy storage device is: ； The liquid phase distribution analysis method of phase change thermal energy storage is as follows: linear interpolation is performed on the temperature of each phase change material to calculate the temperature field distribution inside the phase change thermal energy storage. The temperature of the phase change material is higher than the melting point of the phase change material and the temperature is lower than the melting point of the phase change material, which is then converted into liquid phase distribution. The phase change time of a phase change thermal energy storage device refers to the time it takes for all phase change materials to completely change from a solid phase to a liquid phase under thermal storage conditions, and the time it takes for all phase change materials to completely change from a liquid phase to a solid phase under thermal release conditions. The internal temperature uniformity of a phase change thermal storage device is judged by calculating the standard deviation of the temperature of each phase change material.

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