A Review of Hybrid and Green House Type Solar Dryers

Solar drying is a renewable, efficient, cheap, and sustainable method of preserving agricultural produce. Recent trends in hybrid and greenhouse–type solar dryers were studied. The study revealed that hybrid and greenhouse–type dryers are robust and efficient because they are mostly embedded with heat generating and circulation systems. They are designed to accommodate large-scale drying of fruits and vegetables with higher rates of drying, reduced drying time and some other specific advantages. Findings also revealed that hybrid and greenhouse type solar dryers are mostly designed for optimum retention of heat to compensate for periods with low illumination. The study also gave insight into design challenges peculiar to these types of dryers, and further revealed that most of the fabrications were based on assumptions, with limited data as references. This review also highlights the cost of procurement, uniformity of airflow, sizing of blower and material selection as some of the factors limiting the utilization of hybrid and greenhouse type solar dryers for drying of fruits, vegetables, and other staple crops.