Performance study of two designs of solar dryers

By Medugu, D. W

Abstract

Two solar dryers (chimney and cabinet) were fabricated and tested in Mubi, Adamawa State, Nigeria. Both have the same basin area. For the solar chimney dryer, the vapor formed due to evaporation, is taken away by the air entering into the drying chamber from one end and escapes through the chimney provided at the top with the aid of the supplied dc fan, while for the solar cabinet dryer, the vapor escapes through hole provided at the side of the system. Both dryers were used to perform experimental test in drying 50kg of tomatoes, pepper and bitter leaves. With solar chimney dryer, results reveal that these quantities of tomatoes, pepper and bitter leaves can be dried within 129, 105 and 84h, respectively giving an average 51% of the time spent for the natural sun drying. With solar cabinet dryer, the same quantities of tomatoes, pepper and bitter leaves can be dried within 138, 129 and 90h, respectively with an average 79% of the time spent for the natural sun drying. It was finally observed that solar chimney dryer yields the best result. The color and the flavor of the food stuffs dried with this dryer are comparable to that of a high quality dried in markets. They are free from microbiological contamination.

 

Key Words : Solar dryers; vapor; experimental test; microbial contamination.

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