Design And Test Of Solar Drying System Based On Folded Plate Heat Collection

With China vigorously carrying out modern energy system planning,traditional drying operations fossil energy consumption,the use of solar energy drying can effectively reduce the proportion of fossil energy,to solve the problem of environmental pollution.China is a largely agricultural country,and agricultural products using solar energy drying can effectively reduce energy consumption.However,due to the uncontrollability of solar energy,there is less research on the solar drying process for agricultural products,and the relevant solar drying experiments are not repeatable,which restricts the development of solar drying technology.Based on the above problems,a solar drying system based on folded-plate collector(solar drying system)was designed and the performance of this system was conducted research.This paper mainly does the following:determine the overall structural design of the solar drying system;optimize the structure of the solar simulator lamp array by numerical simulation technology;optimize the structure of the folding plate type solar air collector by numerical simulation technology;conduct indoor and outdoor experiments to test and experiment the performance of the solar drying system.The main research contents of this paper are as follows:(1)The numerical model of the single lamp and arc-shaped lamp array of the solar simulator was established and verified,and the structure optimization design of the lamp array arrangement of the solar simulator was carried out by an orthogonal test.The experimental results showed that the biggest influence on the unevenness of irradiance was the tilt angle of both sides of the lamp,followed by the height of the lamp array,and the best arc-shaped lamp array structure was determined as the height of the lamp array1200mm,the spacing of the same pole lamp source 320mm,the spacing of the horizontal two poles 275mm,the tilt angle of both sides of the lamp 2°,the spacing of the vertical pole 100mm,under this structure the effective radiation surface of 500mm×500mm Irradiance unevenness was 6.99%,and the average irradiance was 1073W/m~2.The irradiance uniformity test of the solar simulator was conducted indoors,and the irradiance inhomogeneity was 7.37%and the average irradiance was 1062 W/m~2 in the effective radiation surface of 500mm×500mm.The stability test of the solar simulator was conducted indoors,and the experimental test result was that the irradiance instability was1.7%,which satisfied the design target.(2)The numerical model of the folding plate solar air collector was established,the numerical model was verified,the structure of the collector was optimized by BBD design,and the experimental results were analyzed to obtain the best combination of parameters for the tilting angle of the folding plate.The best combination was a tilting angle of-10°for folding plate 1,10°for folding plate 2,-10°for folding plate 3,and 10°for folding plate 4.The optimal parameters collectors were optimized for opening,and the two optimized collectors were experimentally compared with the basic folding plate collector.The outlet temperature of the tilted folding plate collector and the open-hole type tilted folding plate collector increased by 1.63K and 2.03K,respectively,and the heat collection efficiency increased by 4.01%and 4.99%,respectively,and the inlet and outlet pressure losses decreased by 44.80%and 43.13%,respectively,which effectively improved The heat collection efficiency of the collector was improved and the outlet pressure loss was greatly reduced.(3)The performance test and experimental study of the solar drying system were conducted for three days of indoor and outdoor experiments,and from the experimental results it was concluded that the maximum error of the collector outlet temperature was2.9 K,and the average relative errors of the outlet temperature were 5.46%,6.86%,and7.31%,respectively;the maximum error of the drying tank inlet temperature was 2.6 K,and the average relative errors of the inlet temperature were 5.90%,5.94%,and 5.70%.Three days of indoor and outdoor sun-dried bitter melon experiments were conducted,and the maximum relative error of moisture ratio was 6.63%from the experimental results,and the average relative error of moisture ratio for the three days of experiments was2.59%,2.26%,and 3.16%,and the overall trend of moisture ratio and drying rate of bitter melon drying was basically the same.Conducted indoor solar bitter melon drying and indoor drying device bitter melon drying experiments,experimental results show that the use of drying device for drying shortened 1h drying time,the average temperature of the outlet of the collector is 324.38 K(51.23°C),the average temperature of the inlet of the drying box is 322.27 K(49.12°C)can be used directly for drying agricultural products.Solar drying system can provide stable and reliable experimental environment can be used for the study of indoor solar drying process.