A small temperature difference plate heat exchanger thermal performance and flow resistance test bench

Abstract

The present application relates to a kind of small temperature difference plate heat exchanger thermal performance and flow resistance test bench, water chiller, water pump, regulating valve, mass flow meter connection form water chiller pipeline;The switching valve group, working medium buffer tank, working medium pump, gas-liquid separation tank connection form working medium side pipeline;Adjustable electric heating thermostatic water tank, stop valve, Y type filter connection form adjustable electric heating thermostatic water tank pipeline;When evaporating working condition test, water chiller pipeline and working medium side pipeline connect auxiliary condenser, working medium side pipeline and adjustable electric heating thermostatic water tank pipeline connect plate heat exchanger test piece;When condensing working condition test, water chiller pipeline and working medium side pipeline connect plate heat exchanger test piece, working medium side pipeline and adjustable electric heating thermostatic water tank pipeline connect auxiliary condenser.By interchanging the flange of plate heat exchanger test piece and auxiliary heat exchanger water side, and switching valve group can quickly realize the switching of evaporating working condition and condensing working condition, improve the use flexibility of test bench.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of small temperature difference plate heat exchanger thermal performance and flow resistance test bench, specifically to a kind of plate heat exchanger for the heat exchanger of marine temperature difference energy power generation system field carries out thermal performance and fluid resistance test test bench. BACKGROUND

[0002] Marine temperature difference energy refers to the heat energy of the temperature difference between the surface seawater and deep seawater, is a clean renewable energy, resource is stable, there is no intermittent, less affected by day and night and season. Marine temperature difference energy power generation is an important way of marine energy, the United States, Japan and India have built marine temperature difference energy power generation demonstration device, also in for the marine temperature difference energy power generation demonstration platform is being built relevant test and prototype development. The cold and hot working medium import and export heat exchange temperature difference of heat exchanger in marine temperature difference energy power generation system is very small, energy density is low, and the required heat exchange area is very large. Secondly, heat exchanger is directly contacted with seawater, and is easily corroded and attached by marine microorganisms, so that the heat exchange efficiency is greatly reduced. Therefore, the type and performance of heat exchanger are put forward to the high requirements in the harsh working environment.

[0003] At present, the type of heat exchanger in the world's major marine temperature difference energy power generation demonstration device is mainly shell and tube type and plate type, and the plate type is the most. Therefore, the test of the thermal performance and fluid resistance of the plate heat exchanger can provide an important basis for the development of small temperature difference, low flow resistance and high efficiency plate heat exchanger products for the domestic marine temperature difference energy power generation demonstration platform and the test of the quality characteristics of the plate heat exchanger products.

[0004] Chinese patent publication No. (CN 102175351 A) discloses a kind of liquid-liquid heat exchanger thermal performance and fluid resistance testing device, but the testing device needs to be assisted by steam heat exchange unit, cold and heat source heat exchange unit, cooling tower, boiler and other test equipment, the test system pipeline is complex, and the pipeline structure is changed greatly when the test condition is switched, and the flexibility is poor.

[0005] In order to meet the requirements of clean, low-carbon and safe and efficient energy development, it is necessary to speed up the development and utilization of clean renewable energy. As the key equipment of marine temperature difference energy power generation system, the heat exchanger is faced with small heat exchange temperature difference, seawater corrosion and other working environment, and the plate heat exchanger in the field of marine temperature difference energy power generation system heat exchanger needs to be tested for thermal performance and fluid resistance, to meet the design requirements of high performance, low flow resistance and stable power generation system. SUMMARY

[0006] The present application is aimed at the above problems, and proposes a kind of small temperature difference plate heat exchanger thermal performance and flow resistance test bench, to reduce the test equipment, simplify the test system pipeline, and improve the flexibility of test bench working condition switching.

[0007] In order to achieve the above object, the technical scheme of the present application is: a small-temperature-difference plate heat exchanger thermal performance and flow resistance test bench, which is used for testing the thermal performance and flow resistance of a plate heat exchanger test piece according to the working condition of a marine temperature difference power generation system heat exchanger, and comprises a water chiller, a water pump, a regulating valve, a mass flow meter, an auxiliary condenser, a switching valve group, a working medium buffer tank, a working medium pump, a plate heat exchanger test piece, a gas-liquid separation tank, an adjustable electric heating constant temperature water tank, a stop valve and a Y-type filter, wherein the water chiller, the water pump, the regulating valve and the mass flow meter are connected to form a water chiller pipeline; the switching valve group, the working medium buffer tank, the working medium pump and the gas-liquid separation tank are connected to form a working medium side pipeline; and the adjustable electric heating constant temperature water tank, the stop valve and the Y-type filter are connected to form an adjustable electric heating constant temperature water tank pipeline; when an evaporation working condition test is performed, the water chiller pipeline and the working medium side pipeline are connected to the auxiliary condenser, and the working medium side pipeline and the adjustable electric heating constant temperature water tank pipeline are connected to the plate heat exchanger test piece; when a condensation working condition test is performed, the water chiller pipeline and the working medium side pipeline are connected to the plate heat exchanger test piece, and the working medium side pipeline and the adjustable electric heating constant temperature water tank pipeline are connected to the auxiliary condenser.

[0008] Further, when the evaporation working condition test and the condensation working condition test are switched, the flanges of the plate heat exchanger test piece and the auxiliary heat exchanger water side are interchanged, and the switching valve group is switched, so that only liquid working medium enters the working medium buffer tank.

[0009] Further, temperature sensors, pressure sensors and flow meters are arranged at the inlet and outlet of the plate heat exchanger test piece, which are used for real-time monitoring of the test working condition, and the cold water temperature of the water chiller is adjusted through a control cabinet to meet the system working condition requirement.

[0010] Further, the adjustable electric heating constant temperature water tank uses a self-provided PLC electric heating control system to set and adjust the water temperature.

[0011] Further, when the evaporation test working condition is performed, the refrigerant in the working medium buffer tank enters the plate heat exchanger test piece through the working medium pump, the switching valve group, the regulating valve and the mass flow meter, exchanges heat with the warm water from the adjustable electric heating constant temperature water tank to evaporate and boil, the working medium vapor and part of the liquid working medium mixture enter the gas-liquid separation tank, the pure working medium vapor separated out enters the auxiliary condenser to exchange heat with the cold water from the water chiller to condense into liquid working medium, and finally enters the working medium buffer tank through the switching valve group, so as to realize working medium circulation.

[0012] Further, the warm water after being cooled by the plate heat exchanger test piece returns to the adjustable electric heating constant temperature water tank through a pipeline; and the cold water in the auxiliary condenser that absorbs the heat of the working medium vapor returns to the water chiller through a pipeline, so as to realize circulation of the warm water and the cold water in the system.

[0013] Furthermore, during the condensation test, the refrigerant in the working fluid buffer tank enters the auxiliary evaporator through the working fluid pump, switching valve group, regulating valve and mass flow meter, where it exchanges heat with the warm water from the adjustable electric heating constant temperature water tank and evaporates and boils. The working fluid vapor and part of the liquid working fluid mixture enter the gas-liquid separator. The separated pure working fluid vapor enters the plate heat exchanger test piece and exchanges heat with the cold water from the chiller unit and condenses into liquid working fluid. Finally, it enters the working fluid buffer tank through the switching valve group, thereby realizing the working fluid circulation.

[0014] Furthermore, the warm water cooled by the auxiliary evaporator returns to the adjustable electrically heated constant temperature water tank through pipelines. The cold water that absorbs heat from the working fluid vapor in the plate heat exchanger test piece returns to the chiller unit through pipelines, thereby realizing the circulation of warm and cold water in the system.

[0015] The beneficial effects of this invention are:

[0016] 1. It reduces the investment in system setup and testing equipment and engineering construction, and simplifies the pipeline of the testing system.

[0017] 2. By interchangeable plate heat exchanger test pieces and auxiliary heat exchanger water-side flanges, and by switching valve groups, the switching between evaporation and condensation conditions can be quickly achieved, improving the flexibility of the test bench.

[0018] 3. The inlet and outlet temperatures, pressures, and flow rates of the plate heat exchanger test pieces and auxiliary heat exchangers can be monitored and precisely adjusted in real time. For the small temperature difference heat exchanger operating conditions of marine thermal power generation systems, this test bench can conduct thermal performance tests and flow resistance characteristic tests at different operating points for evaporation and condensation tests, and finally obtain comprehensive test results for the plate heat exchanger test pieces. Attached Figure Description

[0019] Figure 1 A schematic diagram of the evaporation test of a plate heat exchanger test piece;

[0020] Figure 2 A schematic diagram of a plate heat exchanger test piece under condensation conditions.

[0021] Wherein: 1—Chiller unit, 2—Water pump, 3—Regulating valve, 4—Mass flow meter, 5—Auxiliary condenser, 6—Switching valve group, 7—Working fluid buffer tank, 8—Working fluid pump, 9—Plate heat exchanger test piece, 10—Gas-liquid separator, 11—Adjustable electric heating constant temperature water tank, 12—Stop valve, 13—Y-type filter. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] like Figure 1As shown in Figure 2, the present invention provides a test bench for the thermal performance and flow resistance of a small temperature difference plate heat exchanger. This bench can be used to test the thermal performance and flow resistance of plate heat exchanger test pieces under evaporation and condensation conditions. The test bench includes a chiller unit 1, a water pump 2, a regulating valve 3, a mass flow meter 4, an auxiliary condenser 5, a switching valve group 6, a working fluid buffer tank 7, a working fluid pump 8, a plate heat exchanger test piece 9, a gas-liquid separator 10, an adjustable electrically heated constant temperature water tank 11, a shut-off valve 12, and a Y-type filter 13.

[0024] The chiller unit 1, water pump 2, regulating valve 3, and mass flow meter 4 are connected to form the chiller unit pipeline; the switching valve group 6, working fluid buffer tank 7, working fluid pump 8, and gas-liquid separator 10 are connected to form the working fluid side pipeline; the adjustable electric heating constant temperature water tank 11, shut-off valve 12, and Y-type filter 13 are connected to form the adjustable electric heating constant temperature water tank pipeline.

[0025] like Figure 1 As shown, during the evaporation test, the chiller unit piping and the working fluid side piping are connected to the auxiliary condenser 5, and the working fluid side piping and the adjustable electric heating constant temperature water tank piping are connected to the plate heat exchanger test piece 9.

[0026] like Figure 2 As shown, during the condensation test, the chiller unit piping and the working fluid side piping are connected to the plate heat exchanger test piece 9, and the working fluid side piping and the adjustable electric heating constant temperature water tank piping are connected to the auxiliary condenser 5.

[0027] When switching between evaporation and condensation test conditions, simply interchange the flanges on the water side of the plate heat exchanger test piece 9 and the auxiliary heat exchanger 5, and switch the switching valve group 6 so that only the liquid working fluid enters the working fluid buffer tank 7.

[0028] like Figure 1 As shown, during the evaporation test, the refrigerant in the working fluid buffer tank 7 enters the plate heat exchanger test piece 9 through the working fluid pump 8, switching valve group 6, regulating valve and mass flow meter. It exchanges heat with the warm water from the adjustable electric heating constant temperature water tank 11 and evaporates and boils. The working fluid vapor and part of the liquid working fluid mixture enter the gas-liquid separator 10. The separated pure working fluid vapor enters the auxiliary condenser 5 and exchanges heat with the cold water from the chiller unit 1 to condense into liquid working fluid. Finally, it enters the working fluid buffer tank 7 through the switching valve group 6, thereby realizing the working fluid circulation.

[0029] The warm water, cooled by the plate heat exchanger test piece 9, returns to the adjustable electrically heated constant temperature water tank 11 through pipelines. The cold water, which absorbs heat from the working fluid vapor in the auxiliary condenser 5, returns to the chiller unit 1 through pipelines, thus realizing the circulation of warm and cold water in the system.

[0030] A mass flow meter 4 is installed on the water side (cold side) inlet pipe of the auxiliary condenser 5, and a temperature sensor (Tfci) and a pressure sensor (Pfci) are installed at the inlet, and a temperature sensor (Tfco) and a pressure sensor (Pfco) are installed at the outlet; a mass flow meter is installed on the working fluid side (hot side) inlet pipe of the auxiliary condenser 5, and a temperature sensor (Tfhi) and a pressure sensor (Pfhi) are installed at the inlet, and a temperature sensor (Tfho) and a pressure sensor (Pfho) are installed at the outlet.

[0031] A mass flow meter is installed on the water side (hot side) inlet pipe of the plate heat exchanger test piece 9, and a temperature sensor (Thi) and a pressure sensor (Phi) are installed at the inlet, and a temperature sensor (Tho) and a pressure sensor (Pho) are installed at the outlet; a mass flow meter is installed on the working fluid side (cold side) inlet pipe of the plate heat exchanger test piece 9, and a temperature sensor (Tci) and a pressure sensor (Pci) are installed at the inlet, and a temperature sensor (Tco) and a pressure sensor (Pco) are installed at the outlet.

[0032] Figure 1 The temperature sensor, pressure sensor, and mass flow meter in the system must be calibrated before the test to ensure the accuracy and reliability of the measurement data. The temperature sensor signal, pressure sensor signal, and mass flow meter signal can be transmitted to the industrial control computer in real time for display and data processing. The chilled water temperature of chiller unit 1 can be adjusted via an internal control cabinet, and the adjustable electrically heated constant temperature water tank 11 can have its water temperature set and adjusted via its built-in PLC electric heating control system.

[0033] When plate heat exchanger test piece 9 undergoes evaporation testing, once the evaporation test conditions stabilize to the design conditions, data can be acquired and recorded on a computer. This includes the mass flow rate Mhi, inlet temperature Thi, inlet pressure Phi, outlet temperature Tho, and outlet pressure Pho on the water side (hot side) of plate heat exchanger test piece 9, and the mass flow rate Mci, inlet temperature Tci, inlet pressure Pci, outlet temperature Tco, and outlet pressure Pco on the working fluid side (cold side). The heat transfer on the water side (hot side) of plate heat exchanger test piece 9 is calculated using the inlet and outlet temperatures and mass flow rate data of the water side; the heat transfer on the working fluid side (cold side) of plate heat exchanger test piece 9 is calculated using the inlet and outlet temperatures and mass flow rate data of the working fluid side; and the fluid resistance characteristics of the water side (hot side) and working fluid side (cold side) can be calculated using the corresponding inlet pressure Phi, outlet pressure Pho, inlet pressure Pci, and Pco, respectively.

[0034] During the evaporation test, the refrigerant in the working fluid buffer tank 7 enters the plate heat exchanger test piece 9 through the working fluid pump 8, switching valve group 6, regulating valve and mass flow meter. It exchanges heat with the warm water from the adjustable electric heating constant temperature water tank 11 and evaporates and boils. The working fluid vapor and part of the liquid working fluid mixture enter the gas-liquid separator 10. The pure working fluid vapor separated enters the auxiliary condenser 5 and exchanges heat with the cold water from the chiller unit 1 to condense into liquid working fluid. Finally, it enters the working fluid buffer tank 7 through the switching valve group 6, thus realizing the working fluid circulation.

[0035] The warm water, cooled by the plate heat exchanger test piece 9, returns to the adjustable electrically heated constant temperature water tank 11 through pipelines. The cold water, which absorbs heat from the working fluid vapor in the auxiliary condenser 5, returns to the chiller unit 1 through pipelines, thus realizing the circulation of warm and cold water in the system.

[0036] like Figure 2 As shown, during the condensation test, the refrigerant in the working fluid buffer tank 7 enters the auxiliary evaporator 5 through the working fluid pump 8, switching valve group 6, regulating valve and mass flow meter. It exchanges heat with the warm water from the adjustable electric heating constant temperature water tank 11 and evaporates and boils. The working fluid vapor and part of the liquid working fluid mixture enter the gas-liquid separator 10. The pure working fluid vapor separated enters the plate heat exchanger test piece 9 and exchanges heat with the cold water from the chiller unit 1 and condenses into liquid working fluid. Finally, it enters the working fluid buffer tank 7 through the switching valve group 6, thus realizing the working fluid circulation.

[0037] The warm water, cooled by the auxiliary evaporator 5, returns to the adjustable electrically heated constant temperature water tank 11 through pipelines. The cold water, which absorbs heat from the working fluid vapor in the plate heat exchanger test piece 9, returns to the chiller unit 1 through pipelines, thus realizing the circulation of warm and cold water in the system.

[0038] A mass flow meter 4 is installed on the water side (cold side) inlet pipe of the plate heat exchanger test piece 9, and a temperature sensor (Tci) and a pressure sensor (Pci) are installed at the inlet, and a temperature sensor (Tco) and a pressure sensor (Pco) are installed at the outlet; a mass flow meter is installed on the working fluid side (hot side) inlet pipe of the plate heat exchanger test piece 9, and a temperature sensor (Thi) and a pressure sensor (Phi) are installed at the inlet, and a temperature sensor (Tho) and a pressure sensor (Pho) are installed at the outlet.

[0039] A mass flow meter is installed on the water side (hot side) inlet pipe of the auxiliary evaporator 5, and a temperature sensor (Tfhi) and a pressure sensor (Pfhi) are installed at the inlet, and a temperature sensor (Tfho) and a pressure sensor (Pfho) are installed at the outlet; a mass flow meter is installed on the working fluid side (cold side) inlet pipe of the auxiliary evaporator 5, and a temperature sensor (Tfci) and a pressure sensor (Pfci) are installed at the inlet, and a temperature sensor (Tfco) and a pressure sensor (Pfco) are installed at the outlet.

[0040] Figure 2 The temperature sensor, pressure sensor, and mass flow meter in the system must be calibrated before the test to ensure the accuracy and reliability of the measurement data. The temperature sensor signal, pressure sensor signal, and mass flow meter signal can be transmitted to the industrial control computer in real time for display and data processing. The chilled water temperature of chiller unit 1 can be adjusted via an internal control cabinet, and the adjustable electrically heated constant temperature water tank 11 can have its water temperature set and adjusted via its built-in PLC electric heating control system.

[0041] When performing a condensation test on plate heat exchanger test piece 9, once the condensation test conditions stabilize to the design conditions, data can be collected and recorded on a computer. This includes the mass flow rate Mci, inlet temperature Tci, inlet pressure Pci, outlet temperature Tco, and outlet pressure Pco on the water side (cold side) of plate heat exchanger test piece 9, and the mass flow rate Mhi, inlet temperature Thi, inlet pressure Phi, outlet temperature Tho, and outlet pressure Pho on the working fluid side (hot side). The heat transfer on the water side (cold side) of plate heat exchanger test piece 9 is calculated using the inlet and outlet temperatures and mass flow rate data of the water side; the heat transfer on the working fluid side (hot side) of plate heat exchanger test piece 9 is calculated using the inlet and outlet temperatures and mass flow rate data of the working fluid side; and the fluid resistance characteristics of the water side (cold side) and the working fluid side (hot side) can be calculated using the corresponding inlet pressure Pci, outlet pressure Pco, inlet pressure Phi, and Pho, respectively.

[0042] During the condensation test, the refrigerant in the working fluid buffer tank 7 enters the auxiliary evaporator 5 through the working fluid pump 8, switching valve group 6, regulating valve and mass flow meter. It exchanges heat with the warm water from the adjustable electric heating constant temperature water tank 11 and evaporates and boils. The working fluid vapor and part of the liquid working fluid mixture enter the gas-liquid separator 10. The pure working fluid vapor separated from the liquid enters the plate heat exchanger test piece 9 and exchanges heat with the cold water from the chiller unit 1 and condenses into liquid working fluid. Finally, it enters the working fluid buffer tank 7 through the switching valve group 6, thus realizing the working fluid circulation.

[0043] The warm water, cooled by the auxiliary evaporator 5, returns to the adjustable electrically heated constant temperature water tank 11 through pipelines. The cold water, which absorbs heat from the working fluid vapor in the plate heat exchanger test piece 9, returns to the chiller unit 1 through pipelines, thus realizing the circulation of warm and cold water in the system.

[0044] A mass flow meter 4 is installed on the water side (cold side) inlet pipe of the plate heat exchanger test piece 9, and a temperature sensor (Tci) and a pressure sensor (Pci) are installed at the inlet, and a temperature sensor (Tco) and a pressure sensor (Pco) are installed at the outlet; a mass flow meter is installed on the working fluid side (hot side) inlet pipe of the plate heat exchanger test piece 9, and a temperature sensor (Thi) and a pressure sensor (Phi) are installed at the inlet, and a temperature sensor (Tho) and a pressure sensor (Pho) are installed at the outlet.

[0045] A mass flow meter is installed on the water side (hot side) inlet pipe of the auxiliary evaporator 5, and a temperature sensor (Tfhi) and a pressure sensor (Pfhi) are installed at the inlet, and a temperature sensor (Tfho) and a pressure sensor (Pfho) are installed at the outlet; a mass flow meter is installed on the working fluid side (cold side) inlet pipe of the auxiliary evaporator 5, and a temperature sensor (Tfci) and a pressure sensor (Pfci) are installed at the inlet, and a temperature sensor (Tfco) and a pressure sensor (Pfco) are installed at the outlet.

[0046] Figure 2 The temperature sensor, pressure sensor, and mass flow meter in the system must be calibrated before the test to ensure the accuracy and reliability of the measurement data. The temperature sensor signal, pressure sensor signal, and mass flow meter signal can be transmitted to the industrial control computer in real time for display and data processing. The chilled water temperature of chiller unit 1 can be adjusted via an internal control cabinet, and the adjustable electrically heated constant temperature water tank 11 can have its water temperature set and adjusted via its built-in PLC electric heating control system.

[0047] When performing a condensation test on plate heat exchanger test piece 9, once the condensation test conditions stabilize to the design conditions, data can be collected and recorded on a computer. This includes the mass flow rate Mci, inlet temperature Tci, inlet pressure Pci, outlet temperature Tco, and outlet pressure Pco on the water side (cold side) of plate heat exchanger test piece 9, and the mass flow rate Mhi, inlet temperature Thi, inlet pressure Phi, outlet temperature Tho, and outlet pressure Pho on the working fluid side (hot side). The heat transfer on the water side (cold side) of plate heat exchanger test piece 9 is calculated using the inlet and outlet temperatures and mass flow rate data of the water side; the heat transfer on the working fluid side (hot side) of plate heat exchanger test piece 9 is calculated using the inlet and outlet temperatures and mass flow rate data of the working fluid side; and the fluid resistance characteristics of the water side (cold side) and the working fluid side (hot side) can be calculated using the corresponding inlet pressure Pci, outlet pressure Pco, inlet pressure Phi, and Pho, respectively.

Claims

1. A test bench for the thermal performance and flow resistance of a small temperature difference plate heat exchanger, used to test the thermal performance and flow resistance of plate heat exchanger test pieces according to the operating conditions of the heat exchanger in an ocean thermal power generation system, characterized in that: The system includes a chiller unit, water pump, regulating valve, mass flow meter, auxiliary condenser, switching valve assembly, working fluid buffer tank, working fluid pump, plate heat exchanger test piece, gas-liquid separator, adjustable electrically heated constant temperature water tank, shut-off valve, and Y-type filter. The chiller unit, water pump, regulating valve, and mass flow meter are connected to form the chiller unit piping; the switching valve assembly, working fluid buffer tank, working fluid pump, and gas-liquid separator are connected to form the working fluid side piping; the adjustable electrically heated constant temperature water tank, shut-off valve, and Y-type filter are connected to form the adjustable electrically heated constant temperature water tank piping. An evaporation test is performed. During testing, the chiller unit piping and working fluid side piping are connected to the auxiliary condenser, and the working fluid side piping and adjustable electric heating constant temperature water tank piping are connected to the plate heat exchanger test piece. During condensation test, the chiller unit piping and working fluid side piping are connected to the plate heat exchanger test piece, and the working fluid side piping and adjustable electric heating constant temperature water tank piping are connected to the auxiliary condenser. When switching between evaporation and condensation test, the flanges on the water side of the plate heat exchanger test piece and the auxiliary heat exchanger are interchanged, and the switching valve group is switched so that only liquid working fluid enters the working fluid buffer tank.

2. The test bench for thermal performance and flow resistance of a small temperature difference plate heat exchanger according to claim 1, characterized in that: Temperature sensors, pressure sensors, and mass flow meters are installed at the inlet and outlet of the plate heat exchanger test piece to monitor the test conditions in real time and adjust the chilled water temperature of the chiller unit through the control cabinet to meet the system operating requirements.

3. The test bench for thermal performance and flow resistance of a small temperature difference plate heat exchanger according to claim 1, characterized in that: The adjustable electric heating constant temperature water tank uses its own PLC electric heating control system to set and adjust the water temperature.

4. The test bench for thermal performance and flow resistance of a small temperature difference plate heat exchanger according to claim 1, characterized in that: During the evaporation test, the working fluid in the working fluid buffer tank enters the plate heat exchanger test piece through the working fluid pump, switching valve group, regulating valve and mass flow meter. It exchanges heat with the warm water from the adjustable electric heating constant temperature water tank and evaporates and boils. The working fluid vapor and part of the liquid working fluid mixture enter the gas-liquid separator. The separated pure working fluid vapor enters the auxiliary condenser and exchanges heat with the cold water from the chiller unit and condenses into liquid working fluid. Finally, it enters the working fluid buffer tank through the switching valve group, thereby realizing the working fluid circulation.

5. The test bench for thermal performance and flow resistance of a small temperature difference plate heat exchanger according to claim 4, characterized in that: The warm water cooled by the plate heat exchanger test piece returns to the adjustable electric heating constant temperature water tank through pipelines; the cold water that absorbs heat from the working fluid vapor in the auxiliary condenser returns to the chiller unit through pipelines, thereby realizing the circulation of warm and cold water in the system.

6. The test bench for thermal performance and flow resistance of a small temperature difference plate heat exchanger according to claim 1, characterized in that: During the condensation test, the working fluid in the working fluid buffer tank enters the auxiliary evaporator through the working fluid pump, switching valve group, regulating valve and mass flow meter. It exchanges heat with the warm water from the adjustable electric heating constant temperature water tank and evaporates and boils. The working fluid vapor and part of the liquid working fluid mixture enter the gas-liquid separator. The separated pure working fluid vapor enters the plate heat exchanger test piece and exchanges heat with the cold water from the chiller unit and condenses into liquid working fluid. Finally, it enters the working fluid buffer tank through the switching valve group, thereby realizing the working fluid circulation.

7. The test bench for thermal performance and flow resistance of a small temperature difference plate heat exchanger according to claim 6, characterized in that: The warm water cooled by the auxiliary evaporator returns to the adjustable electric heating constant temperature water tank through pipelines, while the cold water that absorbs heat from the working fluid vapor in the plate heat exchanger test piece returns to the chiller unit through pipelines, thus realizing the circulation of warm and cold water in the system.

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