Design, fabrication and performance analysis of a mixed mode solar dryer for drying vegetables

A study on performance of solar dryer was carried out, it involved; design, fabrication, testing and studying the drying kinetics of a solar dryer.A natural convection mixed-mode solar dryer was used for drying vegetables with the intention of maintaining the colour, minimising drying time and increasing the shelf-life.The results obtained from the experiments conducted in the month of May revealed that the temperatures inside the dryer and solar collector were much higher than the ambient temperature during most of the day-light.The optimum temperature of the solar flat plate collector was 74 and that of drying chamber was 56 with corresponding ambient temperature of 42 .Thermal efficiency of solar collector was found to be 38%.The system drying efficiency of solar dryer was found to be 15%.The dryer reveals its ability to dry food items rapidly to a safe moisture level.It can be used to replace electrical and conventional dryer in semi-urban and rural areas of India.