Study On The Characteristics Of PCM Cooling Photovoltaic Module And Its Application In Refrigerated Self-pick-up Cabinet

As the main circulation mode of fresh products,the key problem of cold chain logistics is whether to enable customers to receive high-quality fresh products.The fresh self-pick-up cabinet can be refrigerated for 24 h and can be delivered at any time,which can effectively guarantee product quality and is an effective solution for the end distribution link of cold chain logistics.At present,all the refrigerated self-pick-up cabinets on the market are cooled by municipal electricity,while the traditional power generation method intensifies the resource consumption and increases the distribution cost.Therefore,the utilization of photovoltaic power supply is particularly important for the development of fresh self-pick-up cabinets.Currently,the widely used crystalline silicon photovoltaic modules have a rapid rise in temperature during operation,thus reducing their photoelectric efficiency and generating capacity.Therefore,in this paper,PCM cooling technology is used to cool photovoltaic modules,and a PCM cooling photovoltaic module system is proposed to provide auxiliary power for the refrigeration cabinet,solve the problem that the photovoltaic modules due to high temperature in the process of work of the decline of the photoelectric efficiency and capacity,improve the utilization rate of photovoltaic energy,the aim of reducing the operating cost of refrigerated self-pick-up cabinet is achieved.At the same time,it provides a new way for the application and development of refrigerated self-pick-up cabinet The main research work and research results are as follows:(1)This paper designs a solar refrigerated self-pick-up cabinet based on phase change material cooling PV modules(PV-PCM),presents a solar refrigerated self-pick-up cabinet system based on PCM cooling PV modules,and analyzes its structure and the factors affecting the performance of PV modules.The thermal load of solar refrigerated self-pick-up cabinet is calculated,the PV-PCM solar refrigerated self-pick-up cabinet is calculated,the models and parameters of main components are determined,the phase change temperature range of phase change materials and the size of PCM plate are determined.(2)The working environment and operating temperature of pv modules were analyzed,and sodium decahydrate sulfate was selected as phase change material for PV modules cooling.In view of the serious phenomena of supercooling and phase separation,the types and dosage of thickeners and nucleating agents were determined,and uniform and stable phase change materials were prepared.Finally,YY-3 was used as a phase change material for cooling photovoltaic modules,with a phase change temperature of 26.2? and a latent heat of 118.7J/g.(3)The heat transfer model of PV-PCM system based on phase change material cooling was established.The influence of PV-PCM system on the operating temperature of PV modules was analyzed through numerical simulation,and the enhanced heat transfer effect of fin on PV-PCM system was analyzed.The results show that the maximum temperature of PV modules in the PV-PCM system is 15.6? lower than that in the conventional PV system.After laying the ribs,the complete melting time of PCM plate during the daytime was extended by 12.7%,and the complete solidification time at night was shortened by 11.8%.(4)The phase change material cooling pv module system is applied to the refrigerated self-pick-up cabinet.The influence of PCM on the operating temperature,output power and photoelectric conversion efficiency of pv modules was studied experimentally.Experiments were carried out on the solar refrigerated self-pick-up cabinet under the conditions of no load and load.The temperature inside the storage compartment,the load temperature,the intake and exhaust temperature of the compressor,the evaporator and condenser temperature were analyzed and tested,and the influence of load on the operating condition of the refrigeration system was studied.The power consumption of solar energy refrigerator is measured under different meteorological conditions.The influence of PV-PCM system on the power consumption of solar energy refrigerator is studied.The results show that the load temperature meets the design requirements and the heat transfer area of evaporator and condenser is fully utilized.In sunny days,when the refrigerated self-pick-up cabinet is used for auxiliary power supply of ordinary PV system and PV system based on phase change material cooling under no-load condition,the electricity saving rate of municipal power can reach 66.9% and 76.3% respectively.When the refrigerated self-pick-up cabinet is used for auxiliary power supply of ordinary PV system and PV system based on phase change material cooling under load,the electricity saving rate of municipal power can reach 43.5% and 51.5% respectively.