| With the increasing demand for energy,the development and utilization of new energy sources is imperative,and solar energy is receiving more and more attention as a clean and renewable green energy source.As a key heat-collecting device for solar thermal utilization technology,flat-plate solar collectors are increasingly welcomed by the market because of their simple structure,strong pressure capacity,easy integration with buildings,and low maintenance costs.More extensive use of solar energy resources can achieve the goal of reducing fossil fuel consumption,saving a lot of conventional energy,and reducing building energy consumption.Many researchers have done a lot of research to improve the thermal efficiency and market competitiveness of flat solar collectors.In this paper,a calculation program is written by MATLAB software,and the simulation calculation and optimization research of a flat-plate solar collector with a double-layer glass cover plate are provided to provide a reference for the optimization of the collector.The specific content is as follows:The composition and structure of the flat-plate solar collector are described,and the principle of flow and heat transfer is analyzed.Based on this,a mathematical model was established based on the reference flat-plate solar collector,and the calculation method of the thermal performance evaluation index of the collector was obtained.The thermal performance index mainly includes the useful energy,efficiency factor,and fin efficiency obtained by the collector,Thermal migration factor,temperature of some components,and instantaneous efficiency.Based on the MATLAB software,a calculation program based on the average temperature of the heat absorbing plate and the average temperature of the working medium in the exhaust pipe was circulated.The influence of the key parameters of the heat absorbing plate,the key parameters of the pipe and the environmental factors on the thermal performance of the collector was studied.In addition,a calculation program based on the average temperature of the heat absorbing plate,the average temperature of the working medium in the row of pipes,and the temperature of the transparent cover plate was compiled.The distance between the transparent cover plate and the heat absorption plate and the surface emissivity of the transparent cover plate was studied.Impact of thermal performance.The research results show that the instantaneous efficiency increased by 23.59% when the surface absorbance of the heatabsorbing plate was changed within the range of 0.80 ? 0.95;the instantaneous efficiency was reduced by 44.04% when the spacing between the pipe rows was changed within the range of 80 ? 240mm;When the temperature is changed in the range of 5 ? 60 ?,the instantaneous efficiency is reduced by 56.59%.Based on this,an optimization analysis of the collector is proposed using the analysis of variance method.Based on the MATLAB software,a calculation program was written based on the analysis of variance method.The key parameters that have a large impact on the instantaneous efficiency of the collector are combined in pairs,and the best combination corresponding to the instantaneous efficiency is obtained,such as the absorption rate and absorption of the heat absorption plate.The best combination of the thermal conductivity of the hot plate is' 0.95,398 W / m·K',and the best combination of the inner diameter of the tube and the inlet temperature of the working medium in the tube is '10°C,30 mm and so on.The experimental test system for instantaneous efficiency of flat solar collectors was established.The experimental test data of instantaneous efficiency of flat solar collectors was obtained through experimental tests,and then compared with the instantaneous efficiency simulation calculation data.The results show that the change trend of the two with the normalized temperature difference is the same,and the deviation value between the two is small,which proves that the calculation program of the flat-plate solar collector written by MATLAB software is correct,and the program can be applied more conveniently The influence of key parameters of flat solar collectors on their instantaneous efficiency was studied. |
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