Performance Investigation of a Chimney-Dependent Solar Crop Dryer for Different Inlet Areas with a Fixed Outlet Area

Abstract

The paper describes the performance of a direct-mode solar crop dryer with a solar chimney. Tests were performed for three differently inclined drying-chamber roofs, each with three inlet areas for a given exit area. Cassava was used as the test crop. The results show that the increase in the inlet area for a given exit area can improve the ventilation in the dryer. However, this does not necessarily improve the drying performance of the direct-mode dryer. A wide inlet area for a given exit area can only improve the drying performance of the direct-mode dryer in a geographical location of low relative humidity. It is therefore not advisable to just copy the design of a direct-mode dryer from one location to another without regard to the ambient relative humidity. The designer and builder of the dryer must consider the relative humidity as a prime factor in the design and construction of direct-mode dryers, which are highly sensitive to the ambient relative humidity.