Design and Implementation of an Automatic Indirect Hybrid Solar Dryer for Households and Small Industries

Abstract

The agricultural sector in most developing nations is seriously impacted with post-harvest losses emanating mainly from the use of inappropriate drying and storage facilities. With regard to these limitations identified, this works discusses the design, the construction and test of an indirect hybrid solar dryer for home and industrial applications. The dryer consists of solar collector, drying chamber, axial fans, photovoltaic solar panels, battery and automatic control devices. The dryer performance was evaluated with tomatoes slices under two drying modes i.e. the solar drying and hybrid solar drying modes. A maximum chamber temperature of 46°C was recorded in the hybrid mode under an average insolation of 318.74W/m² while 39.9°C was attained in the solar mode with an average insolation condition of 303.7W/m². The average drying rate in hybrid mode was computed as 19.7g/h with 6.83% efficiency whereas 10.5g/h was obtained in solar mode with 4.8% efficiency. On the basis of moisture content, the drying test revealed that the quality of the product dried using the hybrid dryer was superior compared to that dried with simple solar dryer alone. Hence proving that this new technology is a viable alternative to open sun drying as well as solar drying methods since the incorporation of a backup heater does not only shortens the retention time, but also allows for a continuous drying process during poor weather conditions and at night.