ABSTRACT
Market demand for dehydrated perishable products is growing as a result of convenience in packaging, cost-effective transportation, and reduced risks of spoilage. Global revenue estimated from dehydrated vegetables was USD 54,241.9 million in 2017, which is expected to grow over 167% (over USD 90,636.0 million) by 2028. Perishable agri-products are dehydrated to minimize post-harvest losses in the long run and to storage safely for meeting the demands in off season as well as to increase the farmers’ revenues. The products are dehydrated by drying either using conventional fossil fuels or renewable energy sources, for example, solar energy. The fossil-fuel-driven drying process is expansive and environmentally hazardous. Therefore, solar drying is being realized as an attractive option, environmentally friendly, and sustainable solution for the sector. Recently, different types of direct and indirect types of solar dryers were developed and tested. However, some limitations, for example, diurnal and seasonal solar radiation and unstable temperatures of hot air, were observed prevalently in solar drying systems, which makes users hesitant to adopt these systems. Efforts are being made to address the limitations and issue in the solar drying systems consistently, and some advanced systems were developed. This chapter discusses the principle of drying, design principles, influencing design parameters for different solar dryers, and advancements in the technology including the continuous and hybrid dryers. Moreover, gaps and opportunities were identified for further advancement in the technology.
*Corresponding author: Email: singh.ramkishore@gmail.com
