Study Of Function Of Greenhouse With Solar Dehydration And Optimization Of Solar Drying Of Fresh Apple Slices

In this paper, the function of efficient collector greenhouse with difference of humidity between inside and outside self-developed by Gansu Academy of Agricultural Sciences Institute of storage and processing of agricultural products was studied. Under this condition, the drying process of fresh apple slices and technology of dehydration with difference of humidity between inside and outside were investigated. Influnces of facts of different different tempreture, humidity, thickness and loadge on dehydration rate were studied. Then the effect of solar and hot air drying apple on energy saving, and environmental protection was researched. The results were as follows:1. The study of the structional function of greenhouse with solar dehydration had revealed that the efficiency of solar energy with vacuum tube collector system had increased by 21 percent. The problems of solar energy reception, conversion and storage were solved by greenhouse roof, collector and water cycle heat exchanger. Dry air resources in western China were fully used of through technology of ventilation and dehumidification, instead of the auxiliary heating system and the problem of low efficiency of night and winter dehydration was resolved. A continuous dehydration operation all year round was achieved by solar enegy and ventilation.2. The data of different tempreture, humidity between inside and outside from computer was recorded. The results were that high tempreture was 71℃in summer, 30℃in winter, different average tempreture between inside and outside 6¹5℃, high tempreture 22³8℃, while with full loadage, inside average humidity 52%, high humidity 80%, outside average humidity 40%, high humidity 70%, different average humidity between inside and outside 12%.3. Under this condition, the drying technics conditions were optimized by response surface analysis and ventilation. The results were that thickness, sample load, indoor and outdoor humidity difference were significantly affected on the dehydration rate. The optimal drying parameters were that thickness was 0.5cm, sample load was 10㎏, and the difference of indoor and outdoor humidity was 15%, the dehydration rate was 0.0165%.min^-1.4. Energy saving and environmental protection of drying apple using solar energy were researched. The effects of energy conservation and reduction of pollutant emissions were obvious and costs of production were reduced. It could meet the needs of energy-saving, environmental protection and sustainable development. The economic benefit was excellent. Compared with the traditional hot air drying, energy-saving rate of solar drying apples was 69.2%. Every 1 ton of dehydrated apple slices produced, could save 4.52 tons of standard coal, while reducing emissions of sulfur dioxide 54.24kg, carbon dioxide 6.78 tons, smoke 67.8kg and ash 1175kg. For every 1 ton dehydrated apple slices, 4,142 yuan could be saved.