Investigation of High Performance Solar Driers

Abstract

It is well known that the thermal performances of solar air collectors are very poor due to low thermal conductivity of air. Therefore, the intention of this research work is to investigate high performance solar air collector that can be used in drying agricultural products like tomato, onion, coffee, banana, etc. so that the drying efficiency will be improved, good quality of product can be obtained and the economy of the farmer as well as the country can be improved.Optimum obstacle shape and geometry and arrangement has been obtained via numerical simulation using ANSYS FLUENT software and further experimental test is conducted in drying tomato and onion in ASTU and coffee drying at Jimma.The solar driers have been manufactured from wood and metal and the both of them have been tested and a better performance have been obtained for the one made from metal because additional solar radiation ise absorbed by the drying chamber surface.Detail experimental work has been done on onion and tomato and thus various test results have been recorded and reported here.After an intensive experimental study out of the total 15 solar driers manufactured (11 by the fund from Finland Embassy and 4 by the fund from ASTU), 13 solar driers of higher efficiency with the obtained optimum obstacles arrangement and configuration have been disseminated to 4 different areas in the country in collaboration with Finland Embassy in Addis Ababa.