Paper Title
EFFECTS OF PHYSICAL PROPERTIES OF FLEECE MATERIAL ON THE DRYING AIR PROPERTIES OF THE MODIFIED GREENHOUSE DRYERS FOR THE DRYING OF COCOA BEANS AND OTHER AGRICULTURAL PRODUCE

Abstract
Greenhouse drying technology for agricultural products has been widely investigated and used globally, but information on the use of fleeces to enhance its drying air properties is limited in literature. The objective of this work was to evaluate the effects of the type and thickness of fleeces of polyester, wool and cotton materials on the temperature and relative humidity profiles of modified greenhouse dryers in the drying of cocoa beans. Using AutocadArchitech 2015, a computer aided design for modified greenhouse dryers equipped with black fleeces was developed and prototypes constructed in the University of Bamenda, Cameroon. Hourly temperature and relative humidity profiles were investigated for three days for each of these fleeces of single, double and triple thicknesses. Tested under no load condition, the cotton fleece (2.56 mm) thick presented significantly higher temperature and lower relative humidity profiles over those of wool (1.56 mm) and polyester (7.86 mm) in descending order. In comparison to the open sun dryer, the observed average temperature differences were 16.1±0.4oC, 14.1±0.4oCand 10.1±1oC for the modified greenhouse dryers equipped with fleeces of cotton, wool and polyester respectively, and 9.5±0.2oC,7.5±0.6oC and 3.5±1.2oC when compared to the conventional greenhouse dryer. Under load conditions, fermented cocoa beans were dried from a moisture content of 54.6% to 3.9%, 3.4% and 3.8% on 18, 27 and 27 hours for the greenhouse dryers modified with fleeces of cotton, wool and polyester respectively and 5.1% and 6.2% for the beans dried concurrently in the conventional greenhouse dryer and the open sun dryers respectively. With the highest regression coefficient (R2) value of 0.97, lowest RMSE of 6.11 and NSE of -0.67, the black fleece of cotton was considered best fit for use in the modified greenhouse dryers, thus validating the model. Keywords - Fleece, Modified Greenhouse Dryer, Open Sun Dryer, Temperature Profile, Cocoa Bean Drying.