Performance evaluation of diminutive solar dryer for drying of green coffee beans: In Ethiopian highlands

Abstract

This Research presents the design and Performance evaluation of a small-scale solar dryer for drying coffee beans in Ethiopia. The unique feature of this dryer is the incorporation of a reflector which significantly enhances solar energy absorption. Unlike conventional solar dryers, this indirect solar dryer employs the solar powered blower to expedite the drying process while preserving the delicate flavor of roasted coffee beans. The experimental result shows that the temperature within the chamber is rising to a maximum of 70 °C. Using natural drying system, for specific sample coffee beans, 5–7 days are needed. Nevertheless, the new dryer could reduce the moisture content of coffee beans from 60 % to 10 % on a wet basis (W.B.) within a couple of days. This is mainly reducing the energy and time wasted by natural drying system to dry coffee beans. Using the analytical approach, the thermal efficiency of this diminutive solar dryer reaches 35.2 %. The finding of this paper is also important to small-scale coffee growers looking for an affordable and environmentally friendly method of drying coffee beans. Future research should explore further optimizations for drying various agricultural products, expanding the dryer's applicability beyond coffee beans.

Keywords

• Solar dryer
• Tilt angle
• Wet basis
• Moisture content
• Coffee beans
• Thermal efficiency