Improvement And Experiment Of Solar Drying Device

The methods of agricultural product processing in China is traditional, the mainly methods of drying agricultural product are heated-air drying and natural drying, drying energy consumption is huge, and the economic benefit basically exchange from energy consumption; and natural drying is facing the test of food safe, due to the factors such as human and weather, enlarge the scale or continuously production still has difficult to complete. Solar energy resources are very rich in China, and agricultural resources are rich, and with good quality, under the current processing demand expands unceasingly, stocking agricultural produce after drying, can improve its economic value, so in the situation of contemporary energy crisis and environmental pressure troubled growing, solar energy research will play a key role in the produce drying. Therefore, in order to use solar energy through the solar-thermal transformation into the process of drying, a scale of solar drying equipment is developed to produce dehydration with solar energy, it can add value to agricultural produce by using new energy.Solar fruit and vegetable drying equipment mainly include solar heating system, drying system and control system three parts. Heating system is composed of several solar collector, on purpose of transformation solar energy into hot thermal energy in air, then input the hot air to the drying system. Drying system is the place of putting materials, hot air transform heat with materials in this system. Control system based on perform components such as fan and electric lever to adjust the wind speed, air volume, temperature and other factors in drying room, to achieve the need of different material in different dry environment.In order to utilize solar energy in agriculture products dehydrating drying via solar-thermal transformation, a kind of flat-plate solar air collector was designed. The optimum structures of collector were presented through series of contrast tests. After performance test on the collector, the equation between air temperature at inlet and outlet and irradiance was obtained. The efficiency of this collector was as high as 84.53%, while the absorber was lateral corrugated, the rate of flow was 0.06 kg/s, the average inlet temperature was 22.16℃, and the average irradiance was 870.60 W/m2; When the average daily environment temperature was 17℃, and the top and bottom passageway spacing ratio was 2:1, the highest temperature in the collector was 87.6℃, risen by 66.4℃ compared with the ambient temperature. The collector has the advantages of low cost, high efficiency and simple structure, which can be used in fields of agricultural products drying dehumidifying.In the garlic drying experiment by the solar drying device, with the result that the garlic slice is 1mm, treatment with solution of 0.4%NaCl, and putted in the upper of the dryer, then can acquire the best quality. This experiment result can be used for improvement of the device and drying method.