Ghasem SADEGHI - Department of Mechanical Engineering, Urmia University of Technology Band Road, Urmia, Iran
TAHERI Okhtay - Department of Mechanical Engineering, Urmia University of Technology Band Road, Urmia, Iran
Farokh MOBADERSANI - Department of Mechanical Engineering, Urmia University of Technology Band Road, Urmia, Iran

Over the past three decades there has been nearly exponential growth in drying R&D on a global scale.Improving of the drying operation to save energy, improve product quality as well as reduce environmental Effect remained as the main objectives of any development of drying system. Solar drying is one of the most attractive and cost-effective methods for agriculture drying. Numerous types of solar dryers have been designed and developed in various parts of the World , yielding varying degrees of technical performance. Basically, there are four types of solar dryers; (1) Open sun dryers, (2) direct solar dryers, (3) indirect solar dryers and (4) mixed-mode dryers. This paper discusses about these types of solar dryers with aspect to the product being dried, technical and economical aspects.

Drying; Solar drying ;Direct drying ;Indirect drying