The dryer was suitable for rural farm applications where grid electricity and fossil fuel are either nonexistent or extremely expensive for average farmer. The optimum method for using for using a solar air collector combined with a grain drying system was investigated by Radajew ski et al., with types of solar collectors, integrated into a roof ; one uncovered (flow under absorber) and one covered (flow over absorber). A computer model was developed to minimize the cost of drying and in doing so optimize the geometry of the collector and the specific rate of air flow through the collector. The results showed an optimum number of hours of operation per day, optimum drying temperature and optimum initial moisture content for any combination of the other variables and the most critical factors affecting annual savings are the length of the drying season and the specific cost of the collector.