Experimental And Simulation Study On The Performance Of Vacuum Glazing Cover Solar Photovoltaic/thermal Collector

Solar photovoltaic/thermal(PV/T)collector combines solar photovoltaic modules with traditional flat-plate solar collector.It generates both electrical and thermal energy.Compared with solar collector or photovoltaic modules,PV/T collector can improve the conversion efficiency of solar energy.PV/T water heating system is a common solar energy comprehensive utilization technology,which is composed of PV/T collector and water tank.When the PV/T water heating system stops operating,the water in the pipe cannot be completely emptied.It is easy to freeze in winter nights and break the pipe.Moreover,the PV/T has a problem of high temperature dissipation which leads to poor thermal performance.This paper proposes a vacuum glazing cover PV/T collector,relying on the thermal insulation performance of vacuum glazing to improve the antifreeze capacity of the PV/T collector and reduce the heat loss.The main work is as follows:The experimental platform of the vacuum glazing cover PV/T water heating system was designed and built.At the same time,the single glazing cover PV/T water heating system was established for comparative study.By comparing the photovoltaic and thermal performance of the two PV/T collectors during the daytime,the temperature difference between the components,and the cooling of the two PV/T collectors at night,show the effect of vacuum glazing cover on the performance of PV/T collector.The main experimental results are:(1)Compared with the single glazing cover PV/T collector,the vacuum glazing cover PV/T collector has higher thermal efficiency and overall efficiency,and the top heat loss is greatly reduced.(2)At night,the initial temperature of the vacuum glazing cover PV/T collector is higher,and the time to drop to the lowest temperature is delayed by 1.5-2 hours.The theoretical model of the vacuum glazing cover PV/T collector was established and verified by the measured data.The theoretical model was used to study the photovoltaic thermal performance of vacuum glazing and single glazing cover PV/T collectors in cold weather conditions.The simulation results show that in cold season,the advantages of vacuum glazing's thermal insulation performance are more prominent,and the overall efficiency of the vacuum glazing cover PV/T collector improved more obviously than the results in spring experiment.The vacuum glazing cover PV/T collector is more suitable for cold seasons or cold areas.