Dryer production capacity can be quantified by the effectiveness coefficient "E-f' defined by the product mass per unit of time in permanent and continuous production. This coefficient depends on the aerothermic parameters and the product quantity contained in the dryer. Previous studies looked at the performances of the solar air collector, the drying chamber and the energy chain, which constituted the coupling of these two components. In this paper, is examined the influence of the aerothermic parameters, and that of product quantity, on the production capacity of this type of solar dryer. The paper concentrates on the elaborate theoretical model making it possible to simulate the running of the energy chain (collector-dryer) in forced convection. (c) 2006 Published by Elsevier Ltd.