Design and fabrication of a double- chamber solar dryer

Object of research: This paper discusses the design and construction of a modified, cost effective solar dryer for use by the average Nigerian farmer or agri-business entrepreneur. Investigated problem: Local farmers often have a lot of difficulties in properly drying harvested agricultural produce for storage and processing purposes, safely and efficiently due to capital constraints. There was therefore a need for an efficient, low cost solar dryer design to aid in this pursuit. Methodology: The designed dryer is a passive dryer that makes use of heat energy tapped through glass collectors placed over the drying and air inlet chambers respectively. The dryer was designed and constructed with carefully selected, inexpensive materials with dimensions of 40cm x 40cm x 60cm for the drying chamber and dimensions of 10cm x 80cm x 40cm for the heating chamber. The glass collectors (4mm thick) were inclined at an angle of incidence of 17.26°. Okra slices were used to test the performance of the dryer. Results / Area of practical use: The study yielded a low cost (€145.60) modified solar dryer capable of drying agricultural produce in a safe and clean way. During eight (8) hours of drying under a temperature range of 39 °C – 45 °C, the initial weight of the okra slices reduced from 150g to 9g, 9g, 10g and 9g on each of the four trays of the drying chamber respectively. Local farmers and agripreneurs will be encouraged to make use of this clean alternative of drying food produce without the drawbacks from regular sun drying. Conclusion: There is need for more work to be done in terms of installation of solar panels to enhance dryer performance. More work should also be carried out on tests during the dry season for increased dryer efficiency.