Inventory and comparative characteristics of dryers used in the sub-Saharan zone: Criteria influencing dryer choice

A thermo-economic analysis was carried out to determine which dryers were most successfully adopted. These dryers will be re-employed by the users when the investment and maintenance costs enable profit to be made from the drying operation. Two types of dryers met those conditions: the traditional simple sun dryer used by families and groups: a study of an application on maize showed costs of €0.01/kg of evaporated water equal to 7% of daily capital gain; the Atesta gas dryer used by small and medium-sized enterprises: applied to pineapple, cost €0.07/kg of evaporated water equal to 9% of daily capital gain. New criteria had to be added to all those listed from the literature in order to choose a dryer properly: characteristics of the product to be dried, product added value, local energy availability and cost, labour skills and availability, local material availability and user investment capacity.