Solar power drying system: a comprehensive assessment on types, trends, performance and economic evaluation

Depletion of natural fuel resources, rising fossil fuel costs and emission have led to use of renewable energies. Use of solar energy for drying is one of the most effective methods due to its renewable nature and availability. Increasing demands for healthy food and low-cost natural foods are fulfilled by solar drying. Miscellaneous types of solar dryers have been introduced and used in several countries based on their design, working and technical performance. Design and performance of natural convection and forced convection solar driers with different configurations have been reviewed. New trends and developments in hybrid dryers are mainly focused in this article. Solar driers especially designed for drying fruits, vegetables, medicinal leafs and grains along with different types of dryers used in different parts of the world are also reviewed. The economic analysis of different driers has also been discussed in this article.