CN114441587B - An experimental device for measuring the performance of phase change materials in temperature difference utilization processes - Google Patents

Abstract

The invention discloses an experimental device for measuring the performance of phase change materials in the temperature difference energy utilization process, which includes a high-pressure accumulator, a constant temperature water bath system, a high-pressure oil collection and replenishment system, a pressure control system and an electromagnetic flowmeter. The high-pressure accumulator holds the phase change material to be measured, and is also equipped with a rubber oil bladder to simulate the working process of the phase change material converting thermal energy into high-pressure oil pressure energy or mechanical energy driven by the heat exchange temperature difference. The pressure control system mainly It uses a high-pressure oil pump and a relief valve to control the pressure in the rubber oil bladder. The electromagnetic flowmeter can accurately measure the volume flow of high-pressure oil to quantify the working ability of the high-pressure oil. The invention can simulate the working process of different phase change materials, different working pressures, different cold source and heat source temperature conditions, and can directly test the volume change rate and working performance of organic phase change materials in the process of utilizing temperature difference energy, and has low cost. , simple operation, strong versatility, and high degree of restoration of the real working process.

Description

An experimental device for measuring the performance of phase change materials in temperature difference utilization processes

Technical field

The invention relates to an experimental device for measuring the performance of phase change materials, and in particular to an experimental device that can directly test the feasibility and working performance of organic phase change materials in the field of temperature difference energy utilization.

Background technique

With the continuous development of scientific research, technical means and social economy, research on marine science, marine resources, and marine environment has received more and more attention. At the same time, achieving reasonable exploration, development, and utilization of marine resources is also of great significance to promoting the long-term and stable development of national energy strategy, military strategy, and economic strategy. Therefore, ocean energy represented by ocean temperature difference has been studied a lot. The so-called ocean temperature difference energy refers to the ocean thermal energy stored in the form of the temperature difference between surface and deep seawater. It has the advantages of huge reserves, clean and renewable, etc. Using the deformation generated by the phase change of temperature difference to directly drive power components or generators is one of the main principles of utilizing ocean temperature difference energy. Among them, phase change materials are the key to realizing phase change driving by temperature difference energy. Phase change materials can complete the solidification process and shrink in volume under the cooling effect of deep seawater below the phase change temperature; or they can shrink in volume under the cooling effect of surface seawater above the phase change temperature. The melting process is completed under the action of heating and the volume expands. The alternating effect of hot and cold seawater can realize the cyclic phase change of phase change materials, thereby realizing the continuous operation of the ocean temperature difference energy utilization system. Currently, the use of phase change materials to utilize temperature difference energy has been initially studied and applied in fields such as ocean vehicle power devices and deep seawater pump water power generation.

In the ocean temperature difference energy utilization device, the phase change volume change rate of the phase change material is the main indicator that affects the performance of the device. Under the same phase change latent heat, the material with a larger phase change volume change rate has stronger work potential and Higher energy conversion efficiency. Currently, organic phase change materials represented by alkanes are mainly used. The phase change temperature of this type of phase change material is between the temperature of surface seawater and deep seawater, and has a large phase change volume change rate, insolubility in water, and chemical resistance. It has the advantages of good stability, good thermal stability, non-toxic, low corrosion, cheap and easy to obtain. In addition, current research devices on the utilization process of ocean temperature difference energy generally separate the phase change heat transfer process of phase change materials from the energy conversion process caused by volume changes of phase change materials, and analyze the phase change processes including heat transfer, phase change, and work. Experimental studies of the entire workflow of variable materials are only possible through complex field tests.

Contents of the invention

Based on the above problems, the present invention discloses an experimental device for measuring the performance of phase change materials in the temperature difference energy utilization process. The purpose is to simply and easily measure the phase change volume change rate of phase change materials, and to evaluate the performance of phase change materials in ocean energy. The temperature difference can be evaluated using the working ability and energy conversion efficiency of the process. It has the advantages of low equipment cost, simple operation, strong versatility, and high degree of restoration of the real working process.

In order to solve the above technical problems, the present invention proposes an experimental device for measuring the performance of phase change materials in the temperature difference energy utilization process, including a high-pressure accumulator, a constant temperature water bath system, a high-pressure oil collection and replenishment system, and a pressure control system; the constant temperature The water bath system includes a water bath, a constant temperature water tank and a PID temperature controller. The constant temperature water tank is equipped with an electric heater and a refrigeration unit connected to the PID temperature controller. The constant temperature water tank is provided with a water inlet and a water outlet. The inlet The water inlet is connected to the water inlet of the water bath box through a water inlet pipe, and the water outlet is connected to the water outlet of the water bath box through a water outlet pipe. The water inlet pipe is provided with a third in sequence from the constant temperature water tank to the water bath box. A valve and a circulating water pump, the water outlet pipe is provided with a second valve; the high-pressure accumulator is arranged in the water bath box, and a rubber oil bladder is provided inside the high-pressure accumulator, and the rubber oil bladder and The space between the metal shells of the high-pressure accumulator is a phase change material cavity. The bottom of the metal shell is provided with a phase change material filling/discharge port. The top of the high-pressure accumulator is in contact with the rubber oil bladder. There is a detachable threaded connection structure in between; the high-pressure oil collection and replenishment system includes a high-pressure oil tank, and a high-pressure oil pipeline is connected from the high-pressure oil tank to the inlet of the rubber oil bag. On the high-pressure oil pipeline, A high-pressure oil pump, a first butterfly valve, an electromagnetic flowmeter and a second butterfly valve are arranged in sequence from the high-pressure oil tank to the rubber oil bag. The electromagnetic flowmeter is connected to a flow accumulator; the pressure control system includes a The pressure transmitter, exhaust branch and overflow branch on the high-pressure oil pipeline; the pressure transmitter is located on the pipe section between the first butterfly valve and the electromagnetic flowmeter; the exhaust branch The pipe section between the second butterfly valve and the rubber oil bag is connected through a first tee, and an exhaust valve is provided on the exhaust branch; the overflow branch is connected through a second tee. On the pipe section between the first butterfly valve and the pressure transmitter, a third butterfly valve and an overflow valve are provided on the overflow branch.

Furthermore, the experimental device for measuring the temperature difference utilization process performance of phase change materials according to the present invention, wherein:

The liquid level of the high-pressure oil tank is simultaneously lower than the outlet of the overflow branch and the inlet of the high-pressure oil pump.

The metal shell of the high-pressure accumulator and the rubber oil bladder are both cylindrical barrel structures.

The phase change material filled in the phase change material cavity is an organic, inorganic or composite liquid-solid phase change material with a phase change temperature between 0 and 100°C.

The outer side of the water bath box is surrounded by thermal insulation cotton.

The volume of high-pressure oil in the rubber oil bladder is 50% to 100% of the volume of the phase change material cavity.

The high-pressure oil tank contains No. 10 aviation hydraulic oil.

Compared with the prior art, the beneficial effects of the present invention are:

The experimental device of the present invention uses a conventional accumulator to contain phase change materials, and thereby simulates the working process of the phase change material converting thermal energy into high-pressure oil pressure energy or mechanical energy driven by the heat exchange temperature difference; using the experimental device of the present invention The experimental device can directly test the volume change rate and working performance of organic phase change materials during the utilization of temperature difference energy. The invention can simulate the working process under different phase change materials, different working pressures, different cold source and heat source temperature conditions, and has the advantages of low cost, simple operation, strong versatility, and high degree of restoration of the real working process.

Description of the drawings

Figure 1 is a schematic structural diagram of an experimental device for measuring the temperature difference utilization process performance of phase change materials according to the present invention;

In the picture:

11-High-pressure accumulator 12-Rubber oil bladder 13-Threaded connection structure 14-Phase change material cavity

20-Water bath 21-PID thermostat 22-Circulating water pump 23-Electric heater

24- Refrigeration unit 25- First valve 26- Second valve 27- Constant temperature water tank

31-Pressure transmitter 32-Third butterfly valve 33-Second butterfly valve 34-First butterfly valve

35-Relief valve 36-High-pressure oil pump 37-High-pressure oil tank 38-Flow totalizer

39-Electromagnetic flowmeter 310-Exhaust valve

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific examples, but the following examples in no way limit the present invention.

The design idea of the experimental device provided by the present invention that can directly test the feasibility and working performance of organic phase change materials in the field of temperature difference energy utilization is: using a conventional high-pressure accumulator to simulate the phase change material in the field of temperature difference energy utilization. It converts the heat transfer and phase change process in the heater, and squeezes (absorbs) the rubber oil bladder through the deformation of the phase change material, thereby completing the energy conversion process from thermal energy to high-pressure oil pressure energy. In addition to the high-pressure accumulator as the main body, it also includes control systems such as phase change heat temperature, high-pressure oil supply/flow/pressure, etc.

As shown in Figure 1, the structure of the experimental device of the present invention is that the experimental device includes a high-pressure accumulator 11, a constant temperature water bath system, a high-pressure oil collection and replenishment system, and a pressure control system.

The constant temperature water bath system includes a water bath 20, a constant temperature water tank 27 and a PID thermostat 21. The constant temperature water tank 27 is provided with an electric heater 23 and a refrigeration unit 24 connected to the PID thermostat 21. The constant temperature water tank 27 There is a water inlet and a water outlet. The water inlet is connected to the water inlet of the water bath box 20 through a water inlet pipe. The water outlet is connected to the water outlet of the water bath box 20 through a water outlet pipe. The water inlet pipe is connected to the water inlet of the water bath box 20. The constant temperature water tank 27 to the water bath tank 20 are successively provided with a first valve 25 and a circulating water pump 22, and the water outlet pipe is provided with a second valve 26. The outer side of the water bath box 20 is surrounded by thermal insulation cotton to ensure that the water bath box 20 is insulated from the outside world.

The high-pressure accumulator 11 is arranged in the water bath 20. A rubber oil bladder 12 is provided inside the high-pressure accumulator 11. The metal shell of the high-pressure accumulator 11 and the rubber oil bladder 12 are both It has a cylindrical barrel structure. The bottom of the metal shell is provided with a phase change material filling/discharging port. There is a detachable threaded connection structure 13 between the top of the high-pressure accumulator 11 and the rubber oil bladder 12 . The volume of high-pressure oil in the rubber oil bladder 12 is 50% to 100% of the volume of the phase change material cavity 14 . The high-pressure oil is No. 10 aviation hydraulic oil. The space between the rubber oil bladder 12 and the metal shell of the high-pressure accumulator 11 is a phase change material cavity 14. The phase change material filled in the phase change material cavity 14 has a phase change temperature between 0 and 100 Organic, inorganic or composite liquid-solid phase change materials between ℃.

The high-pressure oil collection and replenishment system includes a high-pressure oil tank 37. A high-pressure oil pipeline is connected from the high-pressure oil tank 37 to the inlet of the rubber oil bag 12. On the high-pressure oil pipeline, from the high-pressure oil tank 37 to The rubber oil bladder 12 is provided with a high-pressure oil pump 36, a first butterfly valve 34, an electromagnetic flow meter 39 and a second butterfly valve 33 in sequence. The electromagnetic flow meter 39 is connected to a flow accumulator 38. In the present invention, the electromagnetic flowmeter 39 can accurately measure the volume flow rate of high-pressure oil to quantify the working ability of high-pressure oil.

The pressure control system includes a pressure transmitter 31 disposed on the high-pressure oil pipeline and an exhaust branch and an overflow branch; the pressure transmitter 31 is located between the first butterfly valve 34 and the electromagnetic flow rate. on the pipe section between the gauges 39; the exhaust branch is connected to the pipe section between the second butterfly valve 33 and the rubber oil bag 12 through the first tee, and the exhaust branch is provided with an exhaust Valve 310; the overflow branch is connected to the pipe section between the first butterfly valve 34 and the pressure transmitter 31 through a second tee, and a third butterfly valve 32 and an overflow branch are provided on the overflow branch. Flow valve 35. In the present invention, the liquid level of the high-pressure oil tank 37 is simultaneously lower than the outlet of the overflow branch and the inlet of the high-pressure oil pump 36 . The pressure control system mainly uses a high-pressure oil pump 36 and a relief valve 35 to control the pressure in the rubber oil bladder 12 .

The electromagnetic flowmeter 39 and the pressure control system in the present invention are both distributed on the high-pressure oil pipeline, which reduces the floor space and complexity of the equipment.

Example:

1. Manufacturing and assembly of the experimental device of the present invention:

(1) Assembly of high-pressure accumulator 11: Purchase a conventional high-pressure accumulator, which has a cylindrical structure with a height of 430mm and an outer diameter of 152mm. The outer wall material is stainless steel and can withstand a maximum pressure of 31.5MPa. There is a rubber oil bladder 12 with a volume of 1L attached inside. The space between the rubber oil bladder 12 and the metal shell of the high-pressure accumulator 11 is a phase change material cavity 14 used to hold the phase change material to be measured, and its volume is 1.5 L. The bottom of the high-pressure accumulator 11 has a phase change material filling/discharging port with a detachable threaded connection structure, which can be used to fill or discharge the phase change material. The top of the high-pressure accumulator 11 is provided with a detachable threaded connection structure 13 for direct connection with the rubber oil bladder 12 .

(2) The temperature control system in the present invention adopts a constant temperature water bath system. Its manufacturing and assembly are as follows: purchasing a constant temperature water tank 27 with refrigeration and heating functions. The temperature control of the constant temperature water tank 27 relies on a PID that can display a temperature indicator. Thermostat 21. The constant temperature water tank 27 is equipped with a circulating water pump 22 connected to the PID thermostat 21, an electric heater 23, a refrigeration unit 24, a water inlet and outlet, and its corresponding first valve 25 and second valve 26. The temperature control system in the present invention also establishes a water bath 20 as a second constant temperature environment, and uses PU pipes as pipelines connecting the water inlet and outlet of the water bath 20 and the water inlet and outlet of the constant temperature water tank 27 . In the present invention, the water outlet of the constant temperature water tank 27 should be set to have a larger flow rate. Ensure sufficient heat exchange in the water bath 20 to reduce experimental errors caused by uneven temperature distribution in the water bath 20 due to heat absorption by the phase change material.

(3) Manufacturing and assembly of high-pressure oil collection and replenishment system and pressure control system: prepare No. 10 aviation hydraulic oil, pressure transmitter 31, high-pressure oil pump 36, high-pressure oil tank 37, and small flow electromagnetic valve with flow totalizer 38 Flow meter 39, three butterfly valves (32, 33 and 34), a relief valve 35 and an exhaust valve 310, high-pressure oil pipe, PU pipe and several adapters. Assemble the above components as shown in Figure 1. Among them, a simple stainless steel open adapter is used at the end of the exhaust branch, and it should be ensured that the placement height of the exhaust port should be higher than the placement height of the high-pressure accumulator 11 to ensure that the gas in the rubber oil bag 12 is earlier than the high-pressure accumulator 11. For the discharge of oil, a high-pressure stainless steel adapter is finally used to connect the high-pressure pipeline of the high-pressure oil collection and replenishment system to the high-pressure accumulator 11.

2. The process of using the experimental device of the present invention to conduct specific experiments:

(1) Phase change material filling:

1-1) Open the connecting thread at the bottom of the high-pressure accumulator 11, and open the connecting thread between the top of the high-pressure accumulator 11 and the rubber oil bag 12 to connect the inside of the high-pressure accumulator 11 with the outside world. Prepare sufficient phase change material to be measured, make the phase change material in a liquid state by ambient temperature or external heating, and place it in a container. With the help of the threaded port and filling port of the phase change material filling/discharge port at the bottom of the high-pressure accumulator 11 The installation pipeline connects the container holding the phase change material to the space between the outside of the rubber oil bladder 12 and the shell of the high-pressure accumulator 11; with the help of the threaded connection structure 13 at the threaded port on the top of the high-pressure accumulator 11 and its connecting pipeline, the connection The high-pressure oil collection and replenishment system and the internal space of the rubber oil bladder 12.

1-2) Place the container containing the phase change material at a position higher than the high-pressure accumulator 11. Under the action of gravity, the phase change material slowly flows into the space between the outer shell of the high-pressure accumulator 11 and the rubber oil bladder 12 ( That is, the phase change material cavity 14), and at the same time due to extrusion, the volume of the rubber oil bladder 12 gradually decreases. Until the volume of the oil bladder 12 reaches the minimum, the phase change material to be measured stops flowing in.

In the present invention, the filling volume of the phase change material to be tested should be greater than 1L and less than 2L as much as possible.

1-3) Keep the threaded connection structure at the bottom of the high-pressure accumulator 11 connected to the container containing the phase change material. Connect the connecting thread structure 13 on the top of the high-pressure accumulator 11 to the high-pressure pipeline of the high-pressure oil collection system, open the first and second butterfly valves (33 and 34) and the exhaust valve 310, and ensure that the third butterfly valve 32 is closed; Turn on the electromagnetic flow meter 39 and the high-pressure oil pump 36. The high-pressure oil is pumped from the high-pressure oil tank 37 into the rubber oil bag 12. The flow totalizer 38 records the amount of high-pressure oil pumped in real time. When the value of the flow accumulator 38 reaches 80% of the rated volume of the rubber oil bladder 12, the high-pressure oil pump 36 is closed, the first and second butterfly valves (33 and 34) and the exhaust valve 310 are closed.

1-4) Disassemble the threaded connection structure at the bottom of the high-pressure accumulator 11 and encapsulate the phase change material cavity 14. Record the quality difference between the container containing the phase change material and the filling pipeline. This value is the total filling mass m of the phase change material filled into the phase change material cavity 14.

(2) Performance test of phase change materials during solidification stage:

2-1) Adjust the relief valve 35 to the pressure to be measured, open the first, second and third butterfly valves (32, 33 and 34), close the exhaust valve 310, run the high-pressure oil pump 36, under the action of the high-pressure oil pump 36 , the pressure in the pipeline of the high-pressure oil collection and replenishment system gradually increases. By observing the pressure transmitter 31 until the pressure in the pipeline is higher than the set pressure of the relief valve 35, the relief valve 35 opens. At this time, the high-pressure oil The flow loop is established; record the pressure transmitter 31 indication at this moment, which is equal to the pressure in the rubber oil bladder 12. Clear the flow totalizer 38 count to zero.

2-2) Adjust the setting value of the PID thermostat 21 to be lower than the phase change temperature. After the temperature of the circulating water in the constant temperature water tank 27 is stabilized, open the first and second valves (25 and 26) and the circulating water pump 22, and the cooling water flows into the water bath. After the tank 20, the high-pressure accumulator 11 is put into the water bath tank 20. The phase change material solidifies in the phase change material cavity 14 in the high-pressure accumulator 11, and its volume shrinks, and the rubber oil bladder 12 expands in volume, causing the inside of the high-pressure pipeline to The high-pressure oil flows into the rubber oil bag 12, and the oil volume and flow rate flowing into the rubber oil bag 12 are recorded in real time by the flow accumulator 38. When the flow rate of the flow accumulator 38 shows no change in the indication for 30 minutes, it can be considered that the solidification of the phase change material is completed; at this time, the value recorded by the electromagnetic flowmeter 39 is V1, and the value recorded by the pressure transmitter 31 is P1. The time from when the accumulator 11 is placed in the water bath 20 to when the electromagnetic flowmeter 39 shows zero for the first time is t1, which is the time it takes for the phase change material to change from the initial temperature to the set temperature.

(3) Measurement of the volume change rate of phase change materials during the melting stage:

3-1) Adjust the relief valve 35 to the pressure to be measured, open the first, second and third butterflies (32, 33 and 34), close the exhaust valve 310, run the high-pressure oil pump 36, under the action of the high-pressure oil pump 36 , the pressure in the pipeline of the high-pressure oil collection and replenishment system gradually increases until the pressure in the pipeline is higher than the set pressure of the overflow valve 35, and the overflow valve 35 opens. At this time, the high-pressure oil flow circuit is established. Record the pressure transmitter 31 indication, which value is equal to the internal pressure of the rubber oil bladder 12. Clear flow totalizer 38 to zero.

3-2) Close the high-pressure oil pump 36 and the first butterfly valve 34; open the temperature control system and adjust the setting value of the PID thermostat 21 to be higher than the phase change temperature. After the temperature of the circulating water in the constant temperature water tank 27 is stabilized, open the first and second butterfly valves 34. Two valves (25 and 26) and circulating water pump 22, after the cooling water flows into the water bath 20, put the high-pressure accumulator 11 into the water bath 20, the phase change material melts in the phase change material cavity 14, and the volume of the phase change material expands , the volume of the rubber oil bladder 12 is squeezed, and the high-pressure oil flows into the collection system. The volume and flow rate of the inflow oil are recorded by the flow accumulator 38 . After the data of the flow accumulator 38 has no change in the indication for 30 minutes, it can be considered that the melting of the phase change material is completed. The value of the electromagnetic flowmeter recorded at this time is V2, the indication of the pressure transmitter 31 is recorded as P2, and the high pressure is recorded The time from when the accumulator 11 is placed in the water bath 20 to when the electromagnetic flowmeter 39 shows zero for the first time is t2, which is the time it takes for the phase change material to phase change from the initial temperature to the set temperature.

(4) End of experiment:

Close the first and second valves (25, 26) and the circulating water pump 22, close the PID thermostat 21, close the first butterfly valve 34, close the high-pressure oil pump 36, adjust the setting value of the relief valve 35 to normal pressure, and pressure control system After the pressure is relieved, close the second and third butterfly valves (32 and 33) and the exhaust valve 310. The phase change material can be left in the phase change material cavity 14 between the high-pressure accumulator 11 and the rubber oil bladder 12, and can be filled from the phase change material after the next measurement or after the threaded connection structure at the bottom of the high-pressure accumulator 11 is disassembled. /The discharge port is discharged to prepare for filling other materials.

3. Data processing during the experiment:

3. Data processing during the experiment:

Phase change material filling volume: V0=m/ρ0;

Material volume change rate during solidification under set pressure: α1=V1/V0;

Material volume change rate during melting under set pressure: α1=V2/V0;

The material absorbs work during solidification under the set pressure: W1=P1×V1;

The material does expansion work when melting under the set pressure: W2=P2×V2;

Material work efficiency during solidification under set pressure: η1=P1×V1/(m×cp×△T1+m×h), where cp is the specific heat capacity at constant pressure, △T1 is the temperature difference before and after solidification, and h is the latent heat of phase change .

Material work efficiency during melting under set pressure: η2=P2×V2/(m×cp×△T2+m×h), where cp is the specific heat capacity at constant pressure, △T is the temperature difference before and after melting, and h is the latent heat of phase change .

Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative and not restrictive. Those of ordinary skill in the art will not Under the inspiration of the present invention, many modifications can be made without departing from the spirit of the present invention, and these all fall within the protection of the present invention.

Claims (7)

1. An experimental device for measuring the performance of phase change materials in the temperature difference energy utilization process, including a high-pressure accumulator (11), which is characterized in that it also includes a constant temperature water bath system, a high-pressure oil collection and replenishment system, and a pressure control system; The constant temperature water bath system includes a water bath (20), a constant temperature water tank (27) and a PID thermostat (21). The constant temperature water tank (27) is equipped with an electric heater (20) connected to the PID thermostat (21). 23) and refrigeration unit (24), the constant temperature water tank (27) is provided with a water inlet and a water outlet, the water inlet is connected to the water inlet of the water bath box (20) through a water inlet pipe, and the water outlet is connected through an outlet. The water pipe is connected to the water outlet of the water bath box (20). The water inlet pipe is sequentially provided with a first valve (25) and a circulating water pump (22) from the constant temperature water tank (27) to the water bath box (20). , the water outlet pipe is provided with a second valve (26); The high-pressure accumulator (11) is arranged in the water bath box (20). A rubber oil bladder (12) is provided inside the high-pressure accumulator (11). The rubber oil bladder (12) and the The space between the metal shells of the high-pressure accumulator (11) is a phase change material cavity (14). The bottom of the metal shell is provided with a phase change material filling/discharging port. The high-pressure accumulator (11) There is a detachable threaded connection structure (13) between the top and the rubber oil bladder (12); The high-pressure oil collection and replenishment system includes a high-pressure oil tank (37), and a high-pressure oil pipeline is connected from the high-pressure oil tank (37) to the inlet of the rubber oil bladder (12). On the high-pressure oil pipeline, The high-pressure oil tank (37) to the rubber oil bag (12) are sequentially provided with a high-pressure oil pump (36), a first butterfly valve (34), an electromagnetic flow meter (39) and a second butterfly valve (33). The meter (39) is connected with a flow accumulator (38); The pressure control system includes a pressure transmitter (31) disposed on the high-pressure oil pipeline and an exhaust branch and an overflow branch; the pressure transmitter (31) is located at the first butterfly valve (34 ) and the electromagnetic flowmeter (39); the exhaust branch is connected to the pipe section between the second butterfly valve (33) and the rubber oil bladder (12) through a first tee. On the exhaust branch, an exhaust valve (310) is provided; the overflow branch is connected between the first butterfly valve (34) and the pressure transmitter (31) through a second tee. On the pipe section, a third butterfly valve (32) and an overflow valve (35) are provided on the overflow branch. 2. The experimental device for measuring the temperature difference utilization process performance of phase change materials according to claim 1, characterized in that the liquid level of the high-pressure oil tank (37) is simultaneously lower than the outlet of the overflow branch and the The inlet of the high-pressure oil pump (36). 3. The experimental device for measuring the process performance of phase change materials in temperature difference utilization according to claim, characterized in that the metal shell of the high-pressure accumulator (11) and the rubber oil bladder (12) are both cylindrical. Barrel structure. 4. The experimental device for measuring the temperature difference utilization process performance of phase change materials according to claim 1, characterized in that the phase change material filled in the phase change material cavity has a phase change temperature between 0 and 100°C. Organic, inorganic or composite liquid-solid phase change materials. 5. The experimental device for measuring the temperature difference utilization process performance of phase change materials according to claim 1, characterized in that the outer side of the water bath (20) is surrounded by thermal insulation cotton. 6. The experimental device for measuring the temperature difference utilization process performance of phase change materials according to claim 1, characterized in that the volume of high-pressure oil in the rubber oil bag (12) is 50% of the volume of the phase change material cavity (14). %~100%. 7. The experimental device for measuring the process performance of phase change materials in temperature difference utilization according to claim 1, characterized in that the high-pressure oil tank (37) contains No. 10 aviation hydraulic oil.