Solar drying is an unsophisticated, yet very ancient technology. It is one of the most accessible and, hence, the most common preservation techniques applied to agricultural products, mainly in tropical regions of the world where the intensity of solar radiation justifies its use. Different types of solar dryers exist and find suitable applications in the preservation of different agro-produce as a proven means of reducing postharvest losses. The present chapter discusses extensively the design procedures for solar drying systems, including the use of rules of thumb, psychrometric charts and design equations. Economic aspects of solar drying systems are also considered. Various case studies, relating to the application of direct-mode, indirect-mode and mixed-mode types of solar drying systems, have been presented. Although direct-mode dryers are generally cheaper to construct, a major drawback in their application is the fact that drying temperatures cannot be regulated, leading to over- or under-drying. It is concluded that well-designed solar crop drying systems are capable of drastically reducing losses of agricultural products occasioned by postharvest spoilage and preservation challenges.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Industrial and Manufacturing Engineering
- Management, Monitoring, Policy and Law