Performance And Applied Reserarch Of The Flat Plate Dual-purpose Solar Collector

As an important solar energy utilization device,flat plate solar collectors have been widely used in daily life and production.According to the type of working medium,flat plate solar collectors can be divided into two types: liquid collectors and air collectors.However,a single working fluid collector cannot meet the needs of different seasons in year-round applications.In view of this problem,this project considers combining the two functions of liquid heat collection and air heat collection.Users can adopt different functions according to heat demand and seasonal changes,thereby effectively improving the annual utilization rate and heat collection performance of the heat collector.Firstly,a mathematical model of heat transfer of each component of the collector is established for the two heat collection modes,and the model is programmed and solved by EES(Engineering Equation Solver)software.The influence of working fluid parameters,structural parameters and environmental parameters on the thermal performance of the collector is studied by the control variable method.Then use TRNSYS software to build the application model of flat plate solar dual-purpose collectors in buildings respectively,and analyze the application effect of collectors throughout the year.The conclusions are as follows:(1)When the mass flow rate of the inlet of the working medium is increased,the thermal efficiency of the collector gradually increases,but the increase is smaller and smaller.Increasing the inlet temperature of the working medium will greatly reduce the thermal performance of the collector,so in practical applications,it should be considered to reduce the inlet temperature of the working medium.(2)The influence of changing the structural parameters on the two working modes of the collector is inconsistent.Based on the original design intention of this paper and economic considerations,the optimal structural parameters in this design are: 9 copper tubes,glass cover and suction The distance between the hot plates is 5cm,and the thickness of the heat absorption plate is 0.06 cm.The influence of changing environmental parameters on the thermal performance of the solar collector in the two modes is basically the same.The environmental temperature has the greatest impact on the thermal performance of the collector,followed by the solar radiation intensity.(3)In the non-heating season,the flat plate solar collector can provide users with domestic hot water.During the period from April 1st to November 1st,the solar collector provides 3540 MJ of heat with a solar guarantee rate of 75%.Dual-purpose collectors in the heating season provide hot air for users.From November 15 th to March 15 th of the next year,the heating capacity of solar collectors is 2255 MJ,and the solar energy guarantee rate is 10%.Therefore,clean and efficient auxiliary energy should be selected to complement it.(4)The initial investment of the solar energy system is 4,436 yuan,and the static investment recovery period is about 6.38 years.It can save about 11.125 tons of carbon dioxide emissions within 15 years of use,and has a good potential for energy saving and carbon reduction.