Natural convection and direct type (NCDT) solar dryers: a review

Abstract

Solar drying is one of the most beneficial and sustainable technologies benevolent to our society. In this paper, comprehensive review of various designs of natural convective and direct type (NCDT) of solar dryers has been brought forward for the simple reason of collating the desired and the most intriguing state of the art of practicing of solar drying technology for the benefit of one and all. Further, the comparison of performance of existing dryers was attempted based on parameters such as design simplicity, capital cost, compactness, portability, thermal performance, and other equally important parameters contributing to the dried product quality attributes. The dryers utilize convection and radiation as a major heat transfer mechanism. Solar dryer based on the conduction mechanism appears to be more efficient and cost-effective. In our opinion, inclusion of the conduction mechanism amongst the prevalent solar dryers will only lead to further consolidation of solar drying technology. The work done by the authors on their innovative solar conduction dryer is also highlighted and its performance compared with the rest of the reported designs of NCDT dryers.

Keywords:

• Direct solar dryer
• natural convection solar dryer
• solar conduction dryer

Disclosure statement

No potential conflict of interest was reported by the authors.