Performance Investigation of an Inflatable Solar Dryer with Steel-Can Solar Air Heater for Drying Coffee and Corn

Abstract

Coffee and corn are the two most important crops in the Philippines. One of the most critical stages, where crop management can be improved, is drying. In coffee, a moisture level of 12% is optimum for minimizing quality degradation throughout lengthy storage periods, whereas, corn requires a moisture content of 13%. With the demand for simple and cost-effective drying technologies, an Inflatable Solar Dryer (ISD) was created and adapted using a Hohenheim-type solar tunnel and Salvatierra-Rojas’ study. A mesh wire served as a drying space and was placed inside the ISD to avoid moisture condensation. A clear polyethylene (PE) film is attached to a reinforced black Polyvinyl Chloride (PVC) film by a zipper to produce a drying tunnel. The tunnel does not require a foundation because the pressure generated by a solar-powered fan sufficiently stabilizes it. The ISD also incorporated steel cans as solar air heaters to boost the temperature of entering air into the chamber and gradually provide heated air temperature to the bottom parts of the crops. Crops were scattered on the mesh wire and blended with a rake. Drying in the open sun was also done in parallel for comparison purposes. After protracted drying, both crops reached the required moisture content. The trial found that the weight of both crops was affected by the drying duration. The difference in weight for coffee is 1.1kg, while for corn is 0.5kg exhibiting a significant advantage in ISD.