The heat from the sun, coupled with the wind, has been used to dry and preserve food crops for several thousand years. Some crops, such as Chili, Bananas, Coffee Beans, timber, need to be dried before they can be used effectively. Sun drying has often developed into solar drying, where drying occurs is in an enclosed, ventilated area–often using polythene, acrylic or glass covering. Present work deals with design, fabrication of double flow solar dryer. Double flow solar air heater is the advanced modification of single flow solar air heater. In the single flow solar air heater, air flows through one side of copper plate whereas in the double flow solar air heater air flow from both side of copper plate and hence more efficient than any other kind of solar air heater.

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Solar Air Heater Double Flow Solar Energy Drying