Study On The Thermal Management Of The PV/PCM System With Internal And External Double Fins

At present,fossil fuel is still the world’s dominant energy source,but it has the issue of serious environmental pollution,increasing carbon emissions and will be exhausted within decades.The energy crisis has become a worldwide challenge.At this time,clean new energy is considered to be an effective solution to the energy crisis.In recent years,solar photovoltaic power generation has developed rapidly by virtue of its advantages of cleanliness and universality.However,its power generation efficiency is affected by working temperature,which seriously restricts power generation performance,so photovoltaic cooling technology arises at the right moment.In order to achieve high-efficiency thermal regulation of photovoltaic(PV)cells,this paper aims to develop a passive PV cooling technology based on phase change materials(PCM).The PCM is connected to the environment by internal and external double fins which forms a thermal bridge.It can effectively improve the poor cooling effect of the system caused by the low PCM thermal conductivity and effectively extend the thermal management cycle of PCM.Firstly,research work on thermal management of photovoltaic power generation systems at home and abroad in recent years from the aspects of air-cooled forced cooling,surface cooling,heat exchanger cooling,natural air cooling,liquid immersion cooling,heat pipe cooling and PCM cooling was summarized in this article,and it focuses on the advantages and disadvantages of PCM cooling system.In order to solve the problems of poor thermal conductivity and short temperature control period of PCM,an internal and external double-finned PV/PCM system was proposed.Secondly,calculation model of internal and external double-finned PV/PCM was established.The grid independence,time step independence and the accuracy of the calculation results were verified to ensure the scientificity and accuracy of the simulation results.Based on the simulation software Fluent,the effects of fin spacing,thickness and length on the thermoelectric performance of the system under constant meteorological parameters were explored,and the optimal structural parameters were determined.At the same time,the response relationship between solar radiation intensity,ambient temperature,photovoltaic cell temperature and PCM liquid fraction in the system was explored.The melting characteristics of PCM,the flow characteristics of liquid PCM and the operating characteristics of PV cell of the system were studied,and the cooling and temperature control mechanism of PCM on the system was revealed.Finally,meteorological data of typical meteorological years were collected,and the relationship of solar radiation variation was fitted based on the Guass model.The ambient temperature,effective sky temperature and wind speed were simplified,and the UDF program of the model boundary condition was written.The matching work of the fin structure parameters of the system with Haikou,Beijing and Harbin was completed respectively.In addition,based on the matching reference value,equipment recovery residual value,discounted cost of the present value of the PV device,PV/PCM system and internal and external double-finned PV/PCM system were calculated and compared.Cash flow charts were plotted,and the net present value,recovery cycle of the system,energy conservation and emission reduction benefits were calculated and analyzed.The research results in this paper open up a new direction for the research of PV cooling system of PCM,and provide important reference value for the design of structural parameters of finned PV/PCM system.