Performance test system and method for solar phase change energy storage air heat collector

Abstract

The invention discloses a performance test system and method for a solar phase change energy storage air heat collector, and relates to a heat transfer and flow resistance performance test system and method for a heat collector, and the system comprises a solar phase change energy storage air heat collector, an instrument measurement unit, a data acquisition unit and a power transmission unit; the output end of the power conveying unit is connected with the heat collector, the signal input end of the instrument measuring unit is connected with the heat collector, and the signal output end of the instrument measuring unit is connected with the data acquisition unit. The method comprises the following steps: S1, early-stage preparation; s2, different air flow experiments are carried out; s3, data acquisition; s4, carrying out experiments under different weather conditions; s5, data analysis; and S6, verifying and summarizing a result. Various signals such as the temperature, the pressure difference, the flow, the solar radiation heat flux density and the environment wind speed of the heat collector can be measured at the same time, the heat transfer and flow resistance performance of an air flow channel and the energy storage and release performance of a phase change material can be conveniently tested, the system structure is compact, the cost is low, the measurement precision is high, and the method is simple and convenient.

Description

Technical Field

[0001] The present invention relates to a heat transfer and flow resistance performance test system and method for a solar collector, in particular to a heat transfer and flow resistance performance test system and method for a solar energy phase change energy storage air collector. Background Art

[0002] Traditional solar air collector technology is mainly based on sensible heat energy storage, while solar energy phase change energy storage air collector technology based on phase change materials has a higher energy storage density than the former, can effectively convert solar energy into heat energy and store it, which is conducive to staggered utilization. In addition, solar energy phase change energy storage air collector technology also has the advantages of strong environmental adaptability and helping to absorb peak radiation heat flow compared with traditional solar air collector technology. At the same time, the heat release time is longer, that is, after the sun goes down or when the sunlight intensity is low, the phase change material can also continuously provide heat to the air flow channel for a certain period of time.

[0003] Currently, domestic and foreign research on solar energy phase change energy storage air collectors mainly focuses on the influence of structural parameters, operating conditions, and types of phase change materials on the performance of the collector. Existing technologies for testing the performance of solar energy phase change energy storage air collectors still have problems such as inconsistent test standards, single method, inconvenient operation, and the collector has a complex structure, limited working condition adaptability, inability to integrate indoor and outdoor tests, and low measurement accuracy. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a performance test system and method for a solar energy phase change energy storage air collector to solve the deficiencies of the existing technology, such as the complex structure of the collector, limited working condition adaptability, inability to integrate indoor and outdoor tests, low measurement accuracy, inconsistent test standards, single method, and inconvenient operation.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A performance test system for a solar energy phase change energy storage air collector includes a solar energy phase change energy storage air collector, an instrument measurement unit, a data acquisition unit, and a power transmission unit; the output end of the power transmission unit is connected to the solar energy phase change energy storage air collector, the signal input end of the instrument measurement unit is connected to the solar energy phase change energy storage air collector, and the signal output end of the instrument measurement unit is connected to the data acquisition unit.

[0006] A further technical solution of the present invention is that the solar phase change energy storage air collector includes a support frame, a phase change material box installed in the support frame, a heat absorption plate installed on the phase change material box, and tempered glass installed on the upper end face of the support frame; the phase change material box is a sealed box structure filled with a phase change material, an air flow channel is provided between the heat absorption plate and the tempered glass located above the heat absorption plate, and an air inlet section and an air outlet section are respectively provided at both ends of the support frame, and the air inlet section and the air outlet section are respectively communicated with the air flow channel; both the air inlet section and the air outlet section adopt a variable-diameter rectifying cavity with a flat inner end and a circular outer end; a phase change material pressure relief port facing upward is provided on the side end of the phase change material box close to the air outlet section.

[0007] A further technical solution of the present invention is that the solar phase change energy storage air collector is installed on a rotating bracket obliquely to the ground; the tempered glass is hermetically connected to the upper end face of the support frame through a tempered glass pressing block on its upper end face and a sealing strip on its lower end face; the coating on the heat absorption plate adopts a commercial blue film or black film; the bottom end and the periphery of the phase change material box are wrapped with heat insulation cotton, and the periphery of the support frame is also fixedly wrapped with heat insulation cotton through an aluminum alloy baffle.

[0008] A further technical solution of the present invention is that the instrument measurement unit includes a differential pressure sensor, an anemometer, a solar radiation intensity meter, a thermocouple, and a platinum resistance temperature sensor; the signal acquisition ends of the differential pressure sensor are respectively installed on the air inlet section and the air outlet section; the anemometer is used to measure the ambient wind speed, the solar radiation intensity meter is used to measure the solar heat flux density, and the platinum resistance temperature sensors are respectively installed on the air inlet section, the air outlet section, and inside the phase change material box; the thermocouple is arranged on the surface of the heat absorption plate to monitor the temperature change on the surface of the heat absorption plate, and the thermocouple is a T-type thermocouple or a K-type thermocouple; pressure tapping ports are also provided inside the platinum resistance temperature sensors on the air inlet section and the air outlet section. The data acquisition unit includes a data acquisition instrument and a data display computer; the signal input end of the data acquisition instrument is respectively connected to the signal output ends of the differential pressure sensor, anemometer, solar radiation intensity meter, thermocouple, and platinum resistance temperature sensor of the instrument measurement unit, and the signal output end of the data acquisition instrument is connected to the data display computer for real-time monitoring and displaying the data of the instrument measurement unit. The power transmission unit includes a vortex flow meter, a vortex blower, and an inverter; the vortex flow meter is connected to the air inlet section through a quick-connect chuck; the vortex flow meter is used to measure the volume flow rate flowing through the collector, and the signal output end of the vortex flow meter is connected to the signal input end of the data acquisition instrument or directly displays the measurement data through its own screen display; the inverter is used to control the volume flow rate flowing through the collector, and the signal output end of the inverter is connected to the vortex blower.

[0009] Another technical solution of the present invention is a performance test method for a solar energy phase change energy storage air collector as described above, and this method includes the following steps: S1. Preliminary preparation Build a test system and prepare experimental materials; S2. Conduct experiments with different air flow rates Under the same weather conditions, sequentially adjust the rotation speed of the vortex blower through a frequency converter, set multiple different air flow rate values. For each set air flow rate value, start the system and begin to collect data; S3. Data collection Use the instrument measurement unit to collect data; meanwhile, measure the volume flow rate flowing through the collector through a vortex flowmeter; S4. Experiments under different weather conditions Under the condition of keeping other conditions unchanged, change the weather conditions and repeat steps S2 - S3; S5. Data analysis S51. Calculate performance parameters: According to the collected data, calculate various performance parameters of the collector; S52. Analyze the influencing laws: Analyze the calculated performance parameters, and study the influencing laws of air flow rate and weather conditions on the heat transfer and flow resistance performance of the collector, the heat collection efficiency, and the energy storage and release performance of the phase change material box; S6. Result verification and summary S61. Result verification: To ensure the accuracy and reliability of the experimental results, conduct multiple repeated experiments and perform statistical analysis on the experimental data; S62. Summarize conclusions: According to the analysis results of the experimental data, summarize the influence of air flow rate and weather conditions on the performance of the solar energy phase change energy storage air collector.

[0010] A further technical solution of the present invention is that in step S2, the setting of multiple different air flow rate values is low flow rate, medium flow rate, and high flow rate; In step S3, using the instrument measurement unit to collect data includes: collecting the temperatures of the air inlet section and the air outlet section of the collector through a platinum resistance temperature sensor, collecting the pressure difference between the air inlet section and the air outlet section through a pressure difference sensor, collecting the ambient wind speed through an anemometer, collecting the solar heat flux density through a pyranometer, collecting the temperature of the heat absorption plate surface through a thermocouple arranged on the surface of the heat absorption plate, and collecting the temperature of the phase change material in the phase change material box through a platinum resistance temperature sensor arranged in the phase change material box; meanwhile, measure the volume flow rate flowing through the collector through a vortex flowmeter; the data collection frequency is to collect once every 1 - 5 minutes; In step S4, the change of weather conditions is to conduct experiments under different weather conditions of sunny, cloudy, and overcast days respectively; In step S51, the heat transfer rate of the air flow channel of the collector is calculated based on the temperatures of the air inlet section and the outlet section of the collector and the air volume flow rate passing through the vortex flowmeter. Further, the heat transfer amount is obtained by integrating the heat transfer rate over the operating time; the heat transfer coefficient of the air flow channel of the collector is calculated according to the temperature of the heat absorption plate and the heat transfer rate of the air flow channel; the friction factor of the air flow channel is calculated by collecting the pressure difference between the inlet and outlet of the collector and the air volume flow rate; the energy storage amount of the phase change material in the phase change material box during the operating period is calculated by measuring the initial temperature and the ending temperature of the experiment of the phase change material, as well as the known latent heat, melting point, and specific heat parameters of the phase change material; the heat collection efficiency of the collector is calculated by comparing the sum of the heat transfer amount of the air flow channel of the collector and the energy storage amount of the phase change material with the solar heat absorbed by the heat absorption plate. In step S52, the variation trends of parameters such as the heat transfer coefficient, the friction factor, and the heat collection efficiency are analyzed as the air flow rate increases; the differences in the energy storage and release performance of the phase change material under different weather conditions are studied, and the influencing rules are visually displayed by drawing graphs for easy analysis and summary.

[0011] A further technical solution of the present invention is that in step S51, the specific process of calculating the heat transfer amount of the collector based on the temperatures of the air inlet section and the outlet section of the collector and the air volume flow rate passing through the vortex flowmeter is as follows: S511. Calculation of the air mass flow rate: The air mass flow rate m is calculated by the following formula ① m = ρV, formula ① In formula ①, m is the air mass flow rate, ρ is the air density, and V is the air volume flow rate; S512. Determination of the specific heat capacity of air at constant pressure: The standard values of the specific heat capacity of air at constant pressure at different temperatures are obtained from the physical property data handbook, and then the standard values are polynomially fitted. The specific heat capacity of air at constant pressure c is determined according to the qualitative temperature, that is, by the following formula ② p : c p = a + bT a + cT a 2 + dT a 3 + eT a 4 , formula ② In formula ②, c p is the specific heat capacity of air at constant pressure, a, b, c, d, and e are constants, and T a is the qualitative temperature of air, and the qualitative temperature is the average value of the inlet and outlet temperatures; S513. Calculation of the temperature difference between the inlet and outlet of air: The platinum resistance temperature sensor is used to measure the temperature T of the air inlet section of the collector respectivelyin and the temperature T of the outlet section out , the temperature difference ΔT between the air inlet and outlet is ΔT = T out - T in ; S514. Calculate the heat transfer rate and the heat transfer amount: After the system reaches a stable state, substitute the calculated air mass flow rate m, the specific heat capacity at constant pressure c of the air p and the temperature difference ΔT between the air inlet and outlet into the heat transfer rate calculation formula Q = mc p ΔT, the heat transfer rate Q of the air flow channel of the collector can be calculated, and further integrated over the experimental operation time t to obtain the heat transfer amount, that is

[0012] A further technical solution of the present invention is that in step S51, the specific process of calculating the heat transfer coefficient of the collector according to the temperature of the heat absorption plate is as follows: S515. Determine the heat transfer temperature difference: Use a thermocouple to accurately measure the temperatures at multiple positions on the surface of the heat absorption plate, and take the average value to obtain the average temperature T of the heat absorption plate p . At the same time, use a platinum resistance temperature sensor to measure the temperature T of the air inlet section in and the temperature T of the outlet section out , and then calculate the average air temperature T a =(T in + T out ) / 2, the heat transfer temperature difference ΔT pa = T p - T a ; S516. Calculate the heat transfer amount: According to the method of calculating the heat transfer rate Q in steps S511 - S514, determine the heat transfer rate Q of the collector under the current working conditions; S517. Determine the heat transfer area: Measure the effective heat transfer area A where the heat absorption plate contacts the air; S518. Calculate the heat transfer coefficient: According to the heat transfer coefficient formula k = Q / (A * ΔT pa ), substitute the determined heat transfer rate Q, heat transfer area A and heat transfer temperature difference ΔT pa into the heat transfer coefficient formula, and the heat transfer coefficient k of the air flow channel of the collector can be calculated.

[0013] A further technical solution of the present invention is that in step S51, the specific process of calculating the friction factor by collecting the pressure difference between the inlet and outlet of the collector and the volume flow rate of the air is as follows: S519. Measure the pressure difference between the inlet and outlet: Use a pressure difference sensor to accurately measure the pressure difference ΔP between the inlet and outlet of the collector; S5110. Obtain the volume flow rate: The air volume flow rate V measured by a vortex flowmeter; S5111. Determine the geometric parameters of the collector: Measure the length L of the air flow channel of the collector and calculate the equivalent diameter D. The equivalent diameter D = (4B) / C, where B is the cross-sectional area of the air flow channel and C is the wetted perimeter of the air flow channel, that is, the perimeter of the fluid in contact with the wall of the air flow channel; S5112. Obtain the air physical property parameters: Find or measure the density ρ and dynamic viscosity μ of the air at the current temperature and pressure; S5112. Calculate the Reynolds number Re: The calculation formula for the Reynolds number Re is Re = Dvρ / μ, where v is the average flow velocity of the air in the air flow channel. The average flow velocity v is calculated from the volume flow rate V and the cross-sectional area B of the air flow channel, that is, v = V / B; S5113. Calculate the friction factor f Substitute the aforementioned equivalent diameter D, the pressure difference ΔP between the inlet and outlet, the length L, the density ρ, and the average flow velocity v into Equation ③ to obtain the friction factor f: f = 2DΔP / (Lρv 2 ), Equation ③

[0014] A further technical solution of the present invention is that in step S51, the specific process of calculating the stored energy of the phase change material in the phase change material box during the operation period by measuring the initial temperature and the end temperature of the experiment of the phase change material, as well as the known latent heat, melting point, and specific heat parameters of the phase change material is as follows; S5114. Judge the phase change situation: When the experiment is carried out, the initial state of the phase change material is solid. Compare the measured initial temperature T start of the phase change material, the end temperature T end of the experiment, and the melting point T melt of the phase change material. If T start < T melt and T end < T melt , then only sensible heat change occurs in the phase change material during the operation period; if T start < T melt and T end > T melt , then both sensible heat change and latent heat change occur in the phase change material; S5115. Calculate the stored energy of the sensible heat part: Whether or not a phase change occurs, the stored energy of the sensible heat part is calculated by the formula Q sensible = MC b ΔT’, where M is the mass of the phase change material, C b is the specific heat of the phase change material, and ΔT’ is the temperature change amount of the phase change material; S5116. Calculate the stored energy of the latent heat part: If the phase change material has a phase change, then the stored energy of the latent heat part needs to be calculated. The calculation formula is Q latent= M1 * R, where M1 is the mass of the phase change material that undergoes a phase change, and R is the latent heat of the phase change material; S5117. Calculate the total energy storage: Add the sensible heat energy storage part and the latent heat energy storage part to obtain the total energy storage of the phase change material during the operation period, that is, Q total = Q sensible + Q latent ; In step S51, the specific process of calculating the heat collection efficiency of the system by comparing the sum of the heat exchange amount of the collector and the energy storage amount of the phase change material with the solar energy heat absorbed by the heat absorption plate is as follows: S5118. Determine the solar energy heat absorbed by the heat absorption plate: Measure the solar heat flux density q through a pyranometer, and at the same time measure the effective daylighting area S of the heat absorption plate; the experimental operation time is t, then the solar energy heat absorbed by the heat absorption plate S5119. Calculate the heat collection efficiency of the system: Add the calculated heat exchange amount E of the collector and the total energy storage Q of the phase change material total and then compare it with the solar energy heat Q solar absorbed by the heat absorption plate. The calculation formula is: η = [(E + Q total ) / Q solar × 100%, where η is the heat collection efficiency, E is the heat exchange amount of the air in the flow channel, Q total is the total energy storage of the phase change material, and Q solar is the solar energy heat absorbed by the heat absorption plate.

[0015] Due to the adoption of the above structure, the performance test system and method for the solar energy phase change energy storage air collector of the present invention have the following beneficial effects compared with the prior art: 1. The present invention has strong working condition adaptability. Since the phase change material box is convenient to disassemble, it can not only test the heat transfer and flow resistance performance of a single air flow channel, but also measure the heat transfer and flow resistance performance of the air flow channel and the energy storage and release performance of the phase change material at the same time. In addition, the present invention can measure the heat transfer and flow resistance performance of the collector under different weather conditions, and is applicable to both outdoor experiments and indoor experiments.

[0016] 2. Due to the ingenious design of the structure and the modular functional design, it takes into account the measurement of various signals such as temperature, pressure difference, heat flux density, wind speed, and flow rate at the same time, and has the advantages of high system integration, high automation, and high measurement accuracy.

[0017] 3. Each sub-unit such as the air flow channel and the phase change material box of the present invention adopts a modular structure, which is easy to disassemble and integrate, convenient for cleaning and later maintenance, has a compact and simple structure, is easy to operate, and has a low cost.

[0018] In summary, the structure of the present invention is compact, with low cost, easy to disassemble and assemble, high system integration, high precision, and simple method, and is expected to be popularized as a general test standard in the field of solar energy phase change energy storage air collectors.

[0019] Next, in combination with the drawings and embodiments, the technical features of the performance test system and method for the solar energy phase change energy storage air collector of the present invention will be further described. Description of the Drawings

[0020] Figure 1 : Schematic diagram of the functional modules of the performance test system for the solar energy phase change energy storage air collector described in Embodiment 1; Figure 2 : Schematic diagram of the connection of each component unit of the performance test system for the solar energy phase change energy storage air collector described in Embodiment 1; Figures 3 - 5 : Schematic diagram of the structure of the solar energy phase change energy storage air collector described in Embodiment 1, where: Figure 3 : Front view sectional view of the solar energy phase change energy storage air collector; Figure 4 : Three-dimensional structure schematic diagram of the solar energy phase change energy storage air collector; Figure 5 : Figure 4 Exploded view of; In the above drawings, the description of each reference numeral is as follows: 1 - Solar energy phase change energy storage air collector, 11 - Tempered glass pressing block, 12 - Tempered glass, 13 - Sealing strip, 14 - Heat absorption plate, 15 - Phase change material box cover plate, 16 - Phase change material box, 17 - Thermal insulation cotton module, 18 - Air flow channel, 19 - Air inlet section, 110 - Air outlet section, 111 - Support frame, 112 - Quick connection chuck, 113 - Aluminum alloy baffle, 114 - Phase change material pressure relief port; 2 - Instrument measurement unit, 21 - Differential pressure sensor, 22 - Anemometer, 23 - Solar radiation intensity meter; 24 - Platinum resistance temperature sensor, 25 - Sensor installation sleeve, 26 - Pressure tapping port; 3 - Data acquisition unit, 31 - Data acquisition instrument, 32 - Data display computer; 4 - Power transmission unit, 41 - Vortex flowmeter, 42 - Vortex blower, 43 - Frequency converter. Detailed Embodiments

[0021] Embodiment 1 Figures 1 - 2 Disclosed herein is a performance test system for a solar energy phase change energy storage air collector, including a solar energy phase change energy storage air collector 1, an instrument measurement unit 2, a data acquisition unit 3, and a power transmission unit 4; the output end of the power transmission unit 4 is connected to the solar energy phase change energy storage air collector 1, the signal input end of the instrument measurement unit 2 is connected to the solar energy phase change energy storage air collector 1, and the signal output end of the instrument measurement unit 2 is connected to the data acquisition unit 3.

[0022] The solar energy phase change energy storage air collector 1 includes a support frame 111, a phase change material box 16 installed in the support frame 111, a heat absorption plate 14 installed on the phase change material box 16, and toughened glass 12 installed on the upper end face of the support frame 111 (see Figures 4 - 5 ); the phase change material box 16 is a sealed box structure containing a phase change material and having a phase change material box cover plate 15, the phase change material box cover plate 15 is arranged below the heat absorption plate 14, and the phase change material box cover plate 15 is fastened to the upper part of the phase change material box 16 through bolts, gaskets or sealing rubber strips to achieve sealing. During experimental tests, phase change materials with different melting points can be selected according to different working conditions. The phase change material has the characteristic of absorbing or releasing a large amount of heat at a specific temperature. When the heat absorbed by the heat absorption plate 14 is transferred to the phase change material, if the temperature reaches the melting point of the phase change material, the phase change material begins to melt, absorbs a large amount of heat and stores it. This process is reversible. When the ambient temperature drops, the phase change material will solidify and release the stored heat. An air flow channel 18 is provided between the heat absorption plate 14 and the toughened glass 12 located above the heat absorption plate 14. Air inlet sections 19 and air outlet sections 110 are respectively provided at both ends of the support frame 111, and the air inlet sections 19 and air outlet sections 110 are respectively communicated with the air flow channel 18. The toughened glass 12 is hermetically connected to the upper end face of the support frame 111 through toughened glass pressing blocks 11 on its upper end face and sealing rubber strips 13 on its lower end face.

[0023] The bottom end and the periphery of the phase change material box 16 are wrapped with heat insulation cotton 17 to reduce heat dissipation, so that the phase change material only exchanges heat with the heat absorption plate 14 as much as possible. The periphery of the support frame 111 is fixedly wrapped with heat insulation cotton 17 through aluminum alloy baffles 113 to further reduce heat dissipation.

[0024] Both the air inlet section 19 and the air outlet section 110 adopt a variable-diameter rectifying cavity with a flat inner end and a circular outer end, which can make the air flow smoothly through the inlet and outlet, reducing the inlet and outlet effects of the collector; a phase change material pressure relief port 114 is provided on the side end of the phase change material box 16 close to the air outlet section 110, and the phase change material pressure relief port 114 is arranged upward to release the system pressure change caused by the volume change during the melting and solidification of the phase change material, improving the pressure-bearing capacity of the collector.

[0025] The phase change energy storage air collector is installed inclined to the horizontal plane to fully absorb solar radiation heat; the coating on the heat absorption plate 14 adopts a commercial blue film or black film; the air inlet section 19 and the air outlet section 110 are respectively connected to the power transmission unit and the exhaust pipe through quick-connect chucks 112.

[0026] The instrument measurement unit 2 includes a differential pressure sensor 21, an anemometer 22, a solar radiation intensity meter 23, a thermocouple, and a platinum resistance temperature sensor 24; the signal acquisition ends of the differential pressure sensor are respectively installed on the air inlet section 19 and the air outlet section 110 of the solar energy phase change energy storage air collector to measure the differential pressure between the air inlet section 19 and the air outlet section 110; the anemometer 22 is used to measure the ambient wind speed, the solar radiation intensity meter 23 is used to measure the solar heat flux density, and the platinum resistance temperature sensors 24 are respectively installed on the air inlet section 19, the air outlet section 110, and inside the phase change material box 16. The platinum resistance temperature sensors on the air inlet section and the air outlet section are used to measure the inlet and outlet temperatures of the collector, and the platinum resistance temperature sensor inside the phase change material box is used to monitor the temperature change of the phase change material; sensor installation sleeves 25 are respectively connected to the air inlet section 19 and the air outlet section 110, and temperature measurement holes are opened on the sensor installation sleeves 25. The platinum resistance temperature sensor 24 is fixed to the temperature measurement hole by threaded connection; the thermocouple is arranged on the surface of the heat absorption plate 14 to monitor the temperature change on the surface of the heat absorption plate 14, and the thermocouple is a T-type thermocouple or a K-type thermocouple.

[0027] The air inlet section 19 and the air outlet section 110 are also provided with pressure tapping ports 26 inside the platinum resistance temperature sensor 24. The pressure tapping ports are used to collect the differential pressure between the air inlet section and the air outlet section, ensuring that the measured differential pressure does not include the local resistance brought by the variable diameter and improving the measurement accuracy of the differential pressure.

[0028] The data acquisition unit 3 includes a data acquisition instrument 31 and a data display computer 32; the signal input ends of the data acquisition instrument 31 are respectively connected to the signal output ends of the differential pressure sensor 21, the anemometer 22, the solar radiation intensity meter 23, the thermocouple, and the platinum resistance temperature sensor 24 of the instrument measurement unit 2, and the signal output end of the data acquisition instrument 31 is connected to the data display computer 32 for real-time monitoring and displaying the data of the instrument measurement unit 2.

[0029] The power transmission unit 4 includes a vortex flowmeter 41, a vortex blower 42, and a frequency converter 43; the vortex flowmeter 41 is connected to the air inlet section 19 through a quick-connect chuck 112; the vortex flowmeter 41 is used to measure the volume flow rate of the air flowing through the collector, and the signal output end of the vortex flowmeter 41 can be connected to the signal input end of the data collector 31, or the measured data can be directly displayed through the built-in display; the frequency converter 43 is used to control the volume flow rate of the air flowing through the collector, and the signal output end of the frequency converter 43 is connected to the vortex blower 42.

[0030] The working principle of the solar energy phase change energy storage air collector described in the first embodiment is as follows: Driven by the vortex blower 42, the external cold air enters the solar energy phase change energy storage air collector through the air inlet section 19 and flows in the air flow channel 18 above the heat absorption plate 14. When sunlight shines on the heat absorption plate 14, the heat absorption plate 14 absorbs heat and heats up, and this heat is transferred to the air flowing through the air flow channel 18 through heat conduction and convection. After the air temperature rises, it flows out from the air outlet section 110. The heat absorption plate 14 transfers heat to the phase change material box 16 through heat conduction. During the day or when solar radiation is sufficient, the phase change material absorbs and stores heat; at night or when radiation is insufficient, the phase change material releases the stored heat and continuously heats the air flow channel 18 through the heat absorption plate 14, extending the energy supply time of the system.

[0031] As a variation of the first embodiment, during the experimental operation, a visualization window can be set on the surface of the support frame 111 to facilitate observing the melting and solidification of the phase change material in the phase change material box 16.

[0032] As another variation of the first embodiment, a heat transfer enhancement element can be installed on the side of the heat absorption plate 14 of the solar energy phase change energy storage air collector facing the air flow channel 18. By comparing with the solar energy phase change energy storage air collector without installing the heat transfer enhancement element, the flow resistance and heat transfer performance of the heat transfer enhancement element can be tested.

[0033] As yet another variation of the first embodiment, fins, foam metal, or nano materials can be installed in the phase change material box 16 to test their heat transfer enhancement performance for the phase change material. Embodiment Two

[0034] A performance test method for a solar energy phase change energy storage air collector mainly studies the effects of operating parameters such as air inlet flow rate and weather conditions on the heat transfer and flow resistance performance of the collector, the heat collection efficiency, and the energy storage and release performance of the phase change material box. This method includes the following steps: S1. Preliminary preparation Build the performance test system for the solar energy phase change energy storage air collector described in Embodiment 1 and prepare the experimental materials.

[0035] S2. Conduct experiments with different air flow rates Under the same weather conditions, such as on a sunny day, adjust the speed of the vortex blower sequentially through the frequency converter, set multiple different air flow rate values, such as low flow rate, medium flow rate, and high flow rate. For each set air flow rate value, start the system to run for a period of time, and start collecting data after the system reaches a stable state.

[0036] S3. Data collection Use the instrument measurement unit to collect data, including: collect the temperatures of the air inlet section and the air outlet section of the collector through platinum resistance temperature sensors, collect the pressure difference between the air inlet section and the air outlet section through a differential pressure sensor, collect the ambient wind speed through an anemometer, collect the solar heat flux density through a pyranometer, collect the temperature of the heat absorption plate surface through thermocouples arranged on the surface of the heat absorption plate, and collect the temperature of the phase change material in the phase change material box through platinum resistance temperature sensors arranged in the phase change material box; at the same time, measure the volume flow rate flowing through the collector through a vortex flowmeter; the data collection frequency is once every 1 - 5 minutes to ensure that the collected data can accurately reflect the operating state of the system.

[0037] S4. Experiments under different weather conditions Under the condition of keeping other conditions unchanged, change the weather conditions to conduct experiments. For different weather conditions such as sunny, cloudy, and overcast days, repeat steps S2 - S3; under different weather conditions, the solar heat flux density will change, which will affect the performance of the collector. By collecting data under different weathers, study the influence of weather conditions on the performance of the collector.

[0038] S5. Data analysis S51. Calculate performance parameters: According to the collected data, calculate various performance parameters of the collector; In step S51, through the temperatures of the air inlet section and the outlet section of the collector and the air volume flow rate flowing through the vortex flowmeter, calculate the heat transfer rate of the air flow channel of the collector, and further integrate the heat transfer rate during the operation time to obtain the heat transfer amount; according to the temperature of the heat absorption plate and the heat transfer rate, calculate the heat transfer coefficient of the air flow channel of the collector; by collecting the pressure difference between the inlet and outlet of the collector and the air volume flow rate, calculate the friction factor of the air flow channel; by measuring the initial temperature and the end temperature of the experiment of the phase change material, as well as the known latent heat, melting point, and specific heat parameters of the phase change material, calculate the energy storage amount of the phase change material in the phase change material box during the operation period; compare the sum of the heat transfer amount of the air flow channel of the collector and the energy storage amount of the phase change material with the solar heat absorbed by the heat absorption plate to calculate the heat collection efficiency of the collector; where: (1) The specific process of calculating the heat transfer of the collector through the temperatures of the air inlet and outlet sections of the collector and the air volume flow rate through the vortex flowmeter is as follows: S511. Calculation of air mass flow rate: Calculate the air mass flow rate m through the following formula ① m = ρV, formula ①; In formula ①, m is the air mass flow rate, ρ is the air density, and V is the air volume flow rate; S512. Determination of specific heat capacity at constant pressure of air: Obtain the standard values of the specific heat capacity at constant pressure of air at different temperatures from a common physical property data handbook, and then perform polynomial fitting on the standard values. Determine the specific heat capacity at constant pressure of air c according to the qualitative temperature, that is, through the following formula ② p : c p = a + bT a + cT a 2 + dT a 3 + eT a 4 , formula ②; In formula ②, c p is the specific heat capacity at constant pressure of air, a, b, c, d, e are constants, and T a is the qualitative temperature of air, and the qualitative temperature is the average of the inlet and outlet temperatures; S513. Calculation of air inlet and outlet temperature difference: Use platinum resistance temperature sensors to measure the temperature T of the air inlet section of the collector in and the temperature T of the outlet section out respectively. The air inlet and outlet temperature difference ΔT = T out - T in ; S514. Calculate the heat transfer: After the system reaches a stable state, substitute the calculated air mass flow rate m, specific heat capacity at constant pressure of air c p and the air inlet and outlet temperature difference ΔT into the heat transfer rate calculation formula Q = mc p ΔT, and the heat transfer rate Q of the air flow channel of the collector can be calculated. Further integrate over the experimental operation time t to obtain the heat transfer, that is (2) The specific process of calculating the heat transfer coefficient of the collector according to the temperature of the heat absorption plate is as follows: S515. Determine the heat transfer temperature difference: Use thermocouples to accurately measure the temperatures at multiple positions on the surface of the heat absorption plate, and take the average value to obtain the average temperature T of the heat absorption plate p . At the same time, use platinum resistance temperature sensors to measure the temperature T of the air inlet section in and the temperature T of the outlet section out, and then calculate the average air temperature T a =(T in +T out ) / 2, the heat transfer temperature difference ΔT pa =T p -T a ; S516. Calculate the heat transfer amount: According to the method of calculating the heat exchange rate Q in steps S511 - S514, determine the heat exchange rate Q of the collector under the current working conditions; S517. Determine the heat transfer area: Measure the effective heat transfer area A where the heat absorption plate contacts the air; S518. Calculate the heat transfer coefficient: According to the heat transfer coefficient formula k = Q / (A * ΔT pa ), substitute the determined heat exchange rate Q, heat transfer area A, and heat transfer temperature difference ΔT pa into the heat transfer coefficient formula, and then the heat transfer coefficient k of the air flow channel of the collector can be calculated; (3) The specific process of calculating the friction factor by collecting the pressure difference at the inlet and outlet of the collector and the volume flow rate of the air is as follows: S519. Measure the pressure difference at the inlet and outlet: Use a pressure difference sensor to accurately measure the pressure difference ΔP at the inlet and outlet of the collector; S5110. Obtain the volume flow rate: Measure the volume flow rate V of the air with a vortex flowmeter; S5111. Determine the geometric parameters of the collector: Measure the length L of the air flow channel of the collector and calculate the equivalent diameter D. The equivalent diameter D=(4B) / C, where B is the cross-sectional area of the air flow channel and C is the wetted perimeter of the air flow channel, that is, the perimeter where the fluid contacts the wall of the air flow channel; S5112. Obtain the physical property parameters of the air: Look up or measure the density ρ and dynamic viscosity μ of the air at the current temperature and pressure; S5112. Calculate the Reynolds number Re: The calculation formula of the Reynolds number Re is Re = Dvρ / μ, where v is the average flow velocity of the air in the air flow channel. This average flow velocity v is calculated from the volume flow rate V and the cross-sectional area B of the air flow channel, that is, v = V / B; S5113. Calculate the friction factor f Substitute the aforementioned equivalent diameter D, pressure difference ΔP at the inlet and outlet, length L, density ρ, and average flow velocity v into Equation ③ to obtain the friction factor f: f = 2DΔP / (Lρv 2 ), Equation ③; (4) The specific process of calculating the stored energy of the phase change material in the phase change material box during the operation period by measuring the initial temperature and the end temperature of the phase change material experiment, as well as the known latent heat, melting point, and specific heat parameters of the phase change material is as follows; S5114. Determine the phase change situation: When the experiment is carried out, the initial state of the phase change material is solid. Compare the measured initial temperature T of the phase change material start , the end temperature T of the experiment end and the melting point T of the phase change material melt . If T start < T melt and T end < T melt , then only sensible heat change occurs in the phase change material during the operation period; if T start < T melt and T end > T melt , then both sensible heat change and latent heat change occur in the phase change material; S5115. Calculate the sensible heat storage energy: Whether or not a phase change occurs, the sensible heat storage energy is calculated by the formula Q sensible = MC b ΔT’, where M is the mass of the phase change material, C b is the specific heat of the phase change material, and ΔT’ is the temperature change of the phase change material; when T start < T melt and T end < T melt , ΔT’ = T end - T start ; when T start < T melt and T end > T melt , the sensible heat part needs to be calculated in two segments, from T start to T melt and from T melt to T end , ΔT’ = (T melt - T start ) + (T end - T melt ); S5116. Calculate the latent heat storage energy: If the phase change material undergoes a phase change, the latent heat storage energy needs to be calculated. The calculation formula is Q latent = M1﹡R, where M1 is the mass of the phase change material that undergoes the phase change, and R is the latent heat of the phase change material; S5117. Calculate the total storage energy: Add the sensible heat storage energy and the latent heat storage energy to obtain the total storage energy of the phase change material during the operation period, that is, Q total = Q sensible + Q latent ; if the phase change material does not undergo a phase change, Q latent = 0, then Q tota l = Q sens ibl e ; (5) The specific process of calculating the heat collection efficiency of the system by comparing the sum of the heat exchange amount of the collector and the energy storage amount of the phase change material with the solar heat absorbed by the heat absorption plate is as follows: S5118. Determine the solar heat absorbed by the heat absorption plate: Measure the solar heat flux density q with a pyrheliometer, and at the same time measure the effective daylighting area S of the heat absorption plate; The experimental operation time is t, then the solar heat absorbed by the heat absorption plate S5119. Calculate the heat collection efficiency of the system: Add the calculated heat exchange amount E of the collector and the total energy storage amount Q of the phase change material total and then compare it with the solar heat absorbed by the heat absorption plate. The calculation formula is: η = [(E + Q total ) / Q solar × 100%, where η is the heat collection efficiency, E is the heat exchange amount of the air in the flow channel, Q total is the total energy storage amount of the phase change material, Q solar is the solar heat absorbed by the heat absorption plate; S52. Analyze the influencing rules: Analyze the calculated performance parameters, and study the influencing rules of air flow rate and weather conditions on the heat transfer and flow resistance performance of the collector, heat collection efficiency, and energy storage and release performance of the phase change material box; For example, analyze the change trends of parameters such as heat transfer coefficient, friction factor, and heat collection efficiency with the increase of air flow rate; Study the differences in the energy storage and release performance of the phase change material under different weather conditions, and visually display the influencing rules by drawing charts (such as line charts, bar charts, etc.) for easy analysis and summary.

[0039] S6. Result verification and summary S61. Result verification: To ensure the accuracy and reliability of the experimental results, conduct multiple repeated experiments and perform statistical analysis on the experimental data; Check whether the differences between the results of different experiments are within a reasonable range. If the differences are large, analyze the reasons and make improvements, such as checking whether the experimental equipment is operating normally and whether the experimental operations are standardized; S62. Summarize the conclusions: According to the analysis results of the experimental data, summarize the influences of air flow rate and weather conditions on the performance of the solar energy phase change energy storage air collector; Draw corresponding conclusions, such as the specific influence relationship between air flow rate and heat transfer coefficient and flow resistance performance, and how weather conditions affect heat collection efficiency and energy storage and release performance of the phase change material; These conclusions will provide important reference basis for the design, optimization, and practical application of the solar energy phase change energy storage air collector.

[0040] In step S3, as many platinum resistance temperature sensors as possible should be used to measure the temperature of the phase change material in the phase change material box; in step S5118, when calculating the solar heat absorbed by the heat absorption plate, corrections should be made according to factors such as the absorptivity of the heat absorption film and the transmittance of the glass. Additionally, in step S5114, computational fluid dynamics can be used to verify the experiment through numerical simulation, and further numerical simulation can be carried out to better judge the phase change process for convenient calculation.

Claims

1. A performance test system for solar phase change energy storage air collector, characterized in that: The invention comprises a solar energy phase change energy storage air collector (1), an instrument measurement unit (2), a data acquisition unit (3), and a power transmission unit (4); the output end of the power transmission unit (4) is connected to the solar energy phase change energy storage air collector (1), the signal input end of the instrument measurement unit (2) is connected to the solar energy phase change energy storage air collector (1), and the signal output end of the instrument measurement unit (2) is connected to the data acquisition unit (3).

2. The performance test system for solar phase change energy storage air collector according to claim 1 is characterized in that: The solar phase-change energy storage air collector (1) comprises a support frame (111), a phase-change material box (16) installed in the support frame (111), a heat-absorbing plate (14) installed on the phase-change material box (16), and a tempered glass (12) installed on the upper end surface of the support frame (111); the phase-change material box (16) is a closed box structure containing phase-change material, and an air flow channel is provided between the heat-absorbing plate (14) and the tempered glass (12) located above the heat-absorbing plate (14). (18), an air inlet section (19) and an air outlet section (110) are respectively provided at both ends of the support frame (111), and the air inlet section (19) and the air outlet section (110) are respectively connected to the air flow channel (18); the air inlet section (19) and the air outlet section (110) both adopt a variable diameter rectifying cavity with a flat inner end and a circular outer end; and a phase change material pressure relief port (114) arranged upward is provided on the side end of the phase change material box (16) close to the air outlet section (110).

3. The performance test system for solar phase change energy storage air collector according to claim 2 is characterized in that: The solar phase change energy storage air collector (1) is installed on a rotating bracket at an angle to the ground; the tempered glass (12) is sealed and connected to the upper end surface of the support frame (111) through a tempered glass pressing block (11) located on its upper end surface and a sealing strip (13) on its lower end surface; the coating on the heat absorbing plate (14) adopts a commercial blue film or black film; the bottom end and surrounding areas of the phase change material box (16) are wrapped with thermal insulation cotton (17), and the surrounding areas of the support frame (111) are also fixedly wrapped with thermal insulation cotton (17) through an aluminum alloy baffle (113).

4. The performance test system for solar phase change energy storage air collector according to claim 2 is characterized in that: The instrument measurement unit (2) comprises a differential pressure sensor (21), an anemometer (22), a pyranometer (23), a thermocouple, and a platinum resistance temperature sensor (24); the signal acquisition end of the differential pressure sensor is respectively installed on the air inlet section (19) and the air outlet section (110); the anemometer (22) is used to measure the ambient wind speed, the pyranometer (23) is used to measure the solar heat flux density, and the platinum resistance temperature sensor (24) is respectively installed on the air inlet section (19), the air outlet section (110) and the phase change material box (16); the thermocouple is arranged on the surface of the heat absorbing plate (14) to monitor the temperature change on the surface of the heat absorbing plate, and the thermocouple is a T-type thermocouple or a K-type thermocouple; the air inlet section (19) and the air outlet section (110) are also provided with a pressure tapping port (26) on the inner side of the platinum resistance temperature sensor (24); The data acquisition unit (3) comprises a data acquisition instrument (31) and a data display computer (32); the signal input end of the data acquisition instrument (31) is respectively connected to the signal output ends of the pressure difference sensor (21), the anemometer (22), the pyranometer (23), the thermocouple, and the platinum resistance temperature sensor (24) of the instrument measurement unit (2); the signal output end of the data acquisition instrument (31) is connected to the data display computer (32) for real-time monitoring and display of data of the instrument measurement unit (2); The power transmission unit (4) comprises a vortex flowmeter (41), a vortex fan (42), and a frequency converter (43); the vortex flowmeter (41) is connected to the air inlet section (19) via a quick-connect chuck (112); the vortex flowmeter (41) is used to measure the volume flow rate flowing through the collector, and the signal output end of the vortex flowmeter (41) is connected to the signal input end of the data acquisition instrument (31) or directly displays the measured data through a built-in screen display; the frequency converter (43) is used to control the volume flow rate flowing through the collector, and the signal output end of the frequency converter (43) is connected to the vortex fan (42).

5. A performance testing method for a solar phase change energy storage air collector according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: S1. Preliminary preparation Build the test system and prepare experimental materials; S2. Experiment with different air flow rates Under the same weather conditions, the speed of the vortex fan is adjusted in sequence through the frequency converter to set multiple different air flow values. For each set air flow value, the system is started to start collecting data; S3. Data collection The data is collected by using the instrument measurement unit; at the same time, the volume flow rate flowing through the collector is measured by a vortex flowmeter; S4. Experiments under different weather conditions While keeping other conditions unchanged, change the weather conditions and repeat steps S2 to S3; S5. Data Analysis S51. Calculate performance parameters: Calculate various performance parameters of the collector based on the collected data; S52. Analyze the influence rules: Analyze the calculated performance parameters and study the influence rules of air flow and weather conditions on the heat transfer and flow resistance performance of the collector, the heat collection efficiency and the energy storage performance of the phase change material box; S6. Results Verification and Summary S61. Result verification: To ensure the accuracy and reliability of the experimental results, repeated experiments were performed and statistical analysis of the experimental data was performed; S62. Conclusion: Based on the experimental data analysis results, summarize the impact of air flow and weather conditions on the performance of solar phase change energy storage air collector.

6. The performance testing method for a solar phase change energy storage air collector according to claim 5, characterized in that: In step S2, the plurality of different air flow values ​​are set to be low flow, medium flow, and high flow; In step S3, collecting data using the instrument measurement unit includes: collecting the temperature of the air inlet section and the air outlet section of the collector through a platinum resistance temperature sensor, collecting the pressure difference between the air inlet section and the air outlet section through a pressure difference sensor, collecting the wind speed of the environment through an anemometer, collecting the heat flux density of solar energy through a pyranometer, collecting the temperature of the surface of the heat absorbing plate through a thermocouple arranged on the surface of the heat absorbing plate, and collecting the temperature of the phase change material in the phase change material box through a platinum resistance temperature sensor arranged in the phase change material box; at the same time, measuring the volume flow through the collector through a vortex flowmeter; the data collection frequency is once every 1 to 5 minutes; In step S4, the changing weather conditions is to conduct experiments under different weather conditions of sunny day, cloudy day and overcast day respectively; In step S51, the heat transfer rate of the air flow channel of the collector is calculated by the temperature of the air inlet section and outlet section of the collector and the volume flow rate of air flowing through the vortex flowmeter, and the heat transfer rate during the operation time is further integrated to obtain the heat transfer amount; the heat transfer coefficient of the air flow channel of the collector is calculated according to the temperature of the heat absorbing plate and the heat transfer rate of the air flow channel; the friction factor of the air flow channel is calculated by collecting the pressure difference between the inlet and outlet of the collector and the volume flow rate of the air; the energy storage of the phase change material in the phase change material box during the operation time period is calculated by measuring the experimental initial temperature and the experimental end temperature of the phase change material, as well as the known latent heat, melting point and specific heat parameters of the phase change material; the heat transfer of the air flow channel of the collector and the sum of the energy storage of the phase change material are compared with the solar energy absorbed by the heat absorbing plate to calculate the heat collection efficiency of the collector; In step S52, the changing trends of parameters such as heat transfer coefficient, friction factor, and thermal collection efficiency are analyzed as the air flow rate increases; the differences in the energy storage and release performance of phase change materials under different weather conditions are studied, and the influencing rules are intuitively displayed by drawing charts to facilitate analysis and summary.

7. The performance testing method for a solar phase change energy storage air collector according to claim 6, characterized in that: In step S51, the specific process of calculating the heat exchange amount of the collector by the temperature of the air inlet section and outlet section of the collector and the air volume flow rate flowing through the vortex flowmeter is as follows: S511. Calculation of air mass flow: Calculate the air mass flow m by the following formula ①, m=ρV,Formula ① In formula ①, m is the air mass flow rate, ρ is the air density, and V is the air volume flow rate; S512. Determination of the specific heat capacity of air at constant pressure: The standard values ​​of the specific heat capacity of air at constant pressure at different temperatures are obtained from the physical property data manual, and then a polynomial fitting is performed on the standard values. According to the qualitative temperature, the specific heat capacity of air at constant pressure c is determined by the following formula ② p : c p =a+bT a +cT a 2 +dT a 3 +eT a 4 , formula ② In formula ②, c p is the specific heat capacity of air at constant pressure, a, b, c, d, e are constants, T a is the qualitative temperature of air, which is the average value of inlet and outlet temperatures; S513. Calculation of air inlet and outlet temperature difference: The temperature T of the air inlet section of the collector is measured by using a platinum resistance temperature sensor. in and outlet temperature T out , the air inlet and outlet temperature difference ΔT = T out -T in ; S514. Calculate the heat transfer rate and heat transfer amount: After the system reaches a stable state, the calculated air mass flow rate m and air constant pressure specific heat capacity c are p Substitute the air inlet and outlet temperature difference ΔT into the heat transfer rate calculation formula Q = mc p ΔT, the heat transfer rate Q of the collector air flow channel can be calculated, and the heat transfer amount can be further obtained by integrating the experimental running time t.

8. The performance testing method for a solar phase change energy storage air collector according to claim 7, characterized in that: In step S51, the specific process of calculating the heat transfer coefficient of the heat collector according to the temperature of the heat absorbing plate is: S515. Determine the heat transfer temperature difference: Use thermocouples to accurately measure the temperature of multiple locations on the surface of the heat absorbing plate, and take the average value to obtain the average temperature T of the heat absorbing plate. p At the same time, the air inlet temperature T is measured using a platinum resistance temperature sensor. in and outlet temperature T out , and then calculate the average air temperature T a =(T in +T out ) / 2, heat transfer temperature difference ΔT pa =T p -T a ; S516. Calculate the heat transfer: According to the method of calculating the heat transfer rate Q in steps S511-S514, determine the heat transfer rate Q of the collector under the current working condition; S517. Determine the heat transfer area: measure the effective heat transfer area A of the heat absorbing plate in contact with the air; S518. Calculate the heat transfer coefficient: According to the heat transfer coefficient formula k = Q / (A*ΔT pa ), the determined heat transfer rate Q, heat transfer area A and heat transfer temperature difference ΔT pa Substituting into the heat transfer coefficient formula, the heat transfer coefficient k of the collector air flow channel can be calculated.

9. The performance testing method for a solar phase change energy storage air collector according to claim 8, characterized in that: In step S51, the specific process of calculating the friction factor by collecting the collector inlet and outlet pressure difference and the air volume flow rate is: S519. Inlet and outlet pressure difference measurement: Use the pressure difference sensor to accurately measure the collector inlet and outlet pressure difference ΔP; S5110. Volume flow acquisition: air volume flow V measured by a vortex flowmeter; S5111. Determine the geometric parameters of the collector: measure the length L of the collector air flow channel and calculate the equivalent diameter D, which is (4B) / C, where B is the cross-sectional area of ​​the air flow channel and C is the wetted perimeter of the air flow channel, i.e., the perimeter of the contact between the fluid and the wall of the air flow channel; S5112. Obtain air physical parameters: Find or measure the density ρ and dynamic viscosity μ of the air at the current temperature and pressure; S5112. Calculate the Reynolds number Re: The calculation formula of the Reynolds number Re is Re=Dvρ / μ, where v is the average flow velocity of the air in the air flow channel, and the average flow velocity v is calculated from the volume flow rate V and the cross-sectional area B of the air flow channel, that is, v=V / B; S5113. Calculate the friction factor f Substituting the above equivalent diameter D, inlet and outlet pressure difference ΔP, length L, density ρ, and average flow velocity v into formula ③, the friction factor f can be obtained: f = 2DΔP / (Lρv 2 ), Equation ③.

10. The performance testing method for a solar phase change energy storage air collector according to claim 9, characterized in that: In step S51, the specific process of calculating the energy storage of the phase change material in the phase change material box during the operation period by measuring the experimental initial temperature and the experimental end temperature of the phase change material, as well as the known latent heat, melting point, and specific heat parameters of the phase change material is as follows; S5114. Determine the phase change situation: During the experiment, the initial state of the phase change material is solid. Compare the experimental initial temperature T of the phase change material obtained by measurement. start , Experiment end temperature T end and the melting point T of the phase change material melt , if T start <T melt And T end <T melt , the phase change material only undergoes sensible heat change during the operation period; if T start <T melt And T end >T melt , then the phase change material undergoes sensible heat change and latent heat change; S5115. Calculation of sensible heat storage: Regardless of whether phase change occurs, the sensible heat storage is calculated by the formula Q sensible =MC b ΔT' calculation, where M is the mass of the phase change material, C b is the specific heat of the phase change material, ΔT' is the temperature change of the phase change material; S5116. Calculate the latent heat storage energy: If the phase change material undergoes phase change, the latent heat storage energy needs to be calculated. The calculation formula is Q latent =M1*R, where M1 is the mass of the phase change material that undergoes phase change, and R is the latent heat of the phase change material; S5117. Calculate the total energy storage: Add the sensible heat storage and latent heat storage to obtain the total energy storage of the phase change material during the operation period, i.e. Q total =Q sensible +Q latent ; In step S51, the specific process of comparing the sum of the heat exchange of the collector and the energy storage of the phase change material with the solar heat absorbed by the heat absorbing plate to calculate the heat collection efficiency of the system is as follows: S5118. Determine the solar heat absorbed by the heat absorbing plate: measure the solar heat flux density q by using a pyranometer, and simultaneously measure the effective daylighting area S of the heat absorbing plate; the experimental running time is t, then the solar heat absorbed by the heat absorbing plate S5119. Calculate the heat collection efficiency of the system: calculate the heat transfer E of the collector and the total energy storage Q of the phase change material total Add together and add the solar heat Q absorbed by the heat absorbing plate solar In comparison, the calculation formula is: η=[(E+Q total ) / Q solar ]×100%, where η is the heat collection efficiency, E is the heat exchange capacity of the air in the flow channel, Q total is the total energy storage of the phase change material, Q solar The solar heat absorbed by the heat absorbing panel.

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