Asymmetric Non-tracking Concentrating Photovoltaic Thermal System Performance Research

The utilization of solar energy is significance to the transformation of energy structure and sustainable development.Photovoltaic thermal integration technology has the functions of outputting thermal energy and electrical energy,and it is an important method of solar energy utilization.On the one hand,using the condenser can increase the radiation intensity per unit area.On the other hand,using the condenser also reduces the area of the photovoltaic panel and the heat collector.Therefore,it's important for solar energy applications to conduct research on concentrating photovoltaic-thermal system.This paper takes asymmetric and non-tracking concentrating photovoltaic-thermal system as the research object with the purpose of analyzing the influence of different factors on the system efficiency and demonstrating the feasibility of the system application.Through the combination of experimental research and theoretical analysis,we have determined the corresponding steady state model and TRNSYS model.The corresponding application suggestions are proposed through influence factors analysis based on model and system economic analysis method.According to the principle of asymmetric and non-tracking concentrating photovoltaic photothermal system,combined with the system evaluation method,the corresponding experimental platform is built.And the steady state experiment and the non-steady state experiment are completed on the experimental platform.It's measured that under the steady-state experimental conditions,the maximum photothermal efficiency is about 31%,and the maximum photovoltaic efficiency is about 11%.Under non-steady-state experimental conditions,the photothermal efficiency is more than 26%,and the photoelectric efficiency is not less than 8.5%.Through the steady model and non-steady model,the influencing factors of the system are analyzed.Combined with the analysis of the influencing factors,the degree of influence of the influencing factors was analyzed.For the photothermal efficiency,the thermal resistance between the photovoltaic panel and the heat-absorbing plate>mass flow>water tank volume>concentration ratio.For the photoelectric efficiency,Concentration ratio>thermal resistance between photovoltaic panel and heat absorption panel>mass flow,and the volume of the water tank has a less significant impact on the photovoltaic efficiency.Through multiple stepwise regression,the PV efficiency formula and the PT efficiency formula are confermed.Combining the economic analysis of the system and the regression analysis of the influencing factors,the design suggestions for the application of the system are proposed.In a villa buildings,when the corresponding volume of the collector per unit area is 300-400L/m~2and the corresponding mass flow rate of the collector per unit area is 50-100kg/h,the system output is higher and the cost recovery period is shorter.A villa in Dalian is used as an example for the application calculation,and the cost recovery period is 5.3 years.Finally,it's found that the asymmetric and non-tracking system has the problem of uneven output throughout the year in the study.So a compound planar double-sided concentrator is designed for this problem.Through simulation,the year-round operation of the concentrator system is compared with the year-round operation of the original concentrator system.This compare proves that output difference between winter and summer of the compound planar double-sided concentrator system is smaller than the original concentrator system which means the new concentrator system has certain feasibility.At the same time,this article Summarizes the combination of concentrating system and architecture and the structural characteristics of concentrators.