Solar driven fan unit for a solar dryer

by Xhevahir BADUNI

Abstract
Drying cocoa is an important step in cocoa processing not only for preservative purposes but also for improvement of flavour and quality of cocoa products. Results showed that in clear sunny conditions, temperatures in the solar drier can obtain around 60oC. Temperatures in the solar drier are always higher than ambient about 10 to 15oC even at night. In the sunny season, cocoa beans can be dried only in 4 to 5 days and 6 to 7 days in the rainy season. When cocoa beans were effectively dried, they also helped to avoid over-fermentation and reduced mould contamination.
Upon fermentation, cocoa beans need to be dried to remove the moisture, to reduce bitterness and astringency and to develop a chocolate brown color. Direct sun drying has been used widely in many cocoa producing countries and may last as long as 2 weeks. Artificial drying can reduce this process to 20 hours. In a dryer hot air is produced by kerosene, biomass fuel fired stoves or solar air heaters.

Further improvement can be achieved by generating forced air flow by means of a fan. In a preliminary specification of a solar driven fan unit the electric power consumption of the fan is fixed to 300 W peak.
Keywords: Drying Cocoa, Photovoltaic Solar Panel, Solar Driven Fan Unit, Modeling and Simulation of Solar Driven Unit.