A Solar-Energy Method for Reducing Coffee-Drying Costs

Abstract

1. Modern coffee-processing facilities that have been developed recently have provided the features of low equipment costs and reduced labor requirements, but are somewhat expensive to operate when electric power is used entirely to heat the drying air. 2. The use of solar energy as a heat source was considered, since previous research where solar heat was used to dry other crops indicates that solar heat-collectors could also be used successfully for drying coffee. 3. An experimental processing facility which employs a solar heat-collector was built and operated, and it has been demonstrated that worthwhile reductions in operating costs can be achieved through the use of solar energy. 4. It was concluded that other coffee producers could economically use solar heat-collectors to reduce electricity costs. Drying facilities should be designed using the following as guides: A. Provide 10 square feet of drying-bin area for each 100 hundred-weights of coffee produced yearly. B. Install a fan which will deliver 100 c.f.m. per square foot of bin area against a static pressure of 1-inch water gage. C. Construct the solar heat-collector according to the specifications presented in figure 1. D. Install electric heating elements which provide up to 5,000 w. for each 100 hundred-weights processed yearly.