Abstract: As the world’s population is increasing, the demand for food is also increasing. Drying techniques increase the life and quality of crop and industrial food products. It also improves the economic condition of farmers. Drying reduces the water stored within the product by evaporation. It can be done by the use of conventional energy and different methods. Sun radiation is used for open sun drying around the globe. Open sun drying has many disadvantages in comparison to other drying techniques. Solar drying is comparatively clean and effective. Solar dryers are of mainly four types: 1) direct solar dryer; 2) indirect solar dryers; 3) mixed mode solar dryer and 4) hybrid solar dryers. Because electric and heat energy demand is increasing day by day worldwide, PV/T solar dryer becomes an interesting and upcoming interest of research nowadays. In this review article basics of different kinds of solar dryers and recent advancements in hybrid PV/T dryers have been presented. Results for drying grapes, medicinal herb, tomato, and wood using PV/T solar dryer are discussed in this study. Variations of drying time, energy consumption, efficiency with different air temperatures, air flow rate and RH are discussed. The use of different solar collectors, solar air heater and heat storage materials with hybrid PV/T dryer have also been reviewed.
Keywords: Drying, solar dryers, greenhouse drying, photovoltaic thermal (PVT), conventional PVT systems
