ADVANCEMENTS IN SOLAR DRYING: A COMPREHENSIVE REVIEW

Abstract: India produces over 200 million tonnes of food grains annually. There is need of postproduction management system to match with the increasing production rate. Drying is the primary need of crop’s postproduction system. Sun drying is a popular mode of crops drying in India. The use of mechanical dryers is almost nil. With ever growing population, the food grain production will increase to meet the demand of people. The crop drying cannot be dependent on sun drying. The produce has to be handled and managed properly to reduce losses. Drying of agriculture produce for safe preservation is one of the important post-harvest operations to save the grain from losses. There is not much facility of drying at farm level, though the losses due to the improper drying is over 10% in food grains and 20 to 40% in fruits and vegetables. Solar drying is a possible replacement for open sun drying. Sun drying is by no means a perfect process with problems arising due to potential contamination of the produce, variability in drying times, rain damage and so on. The present paper presents developments in solar dryer designs for different dryer classifications. Recommendations for energy-efficient design and measures for improvement in existing dryers are also discussed.

Keyword: Solar dryer, Sun drying, Post-harvest loss