Study on effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans

The main objective is to assess effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans. Two type of desiccants were tested, molecular sieve 13 x (Na86 [(AlO2)86.(SiO2)1061 264H(2)O) as an adsorbent type and CaCl2 as an absorbent type. The results revealed that during sunshine hours, the maximum temperature within the drying chamber varied from 40 degrees C to 54 degrees C. In average, it was 9-12 degrees C higher than ambient temperature. These temperatures are very suitable for drying cocoa beans. During off-sunshine hours, humidity of air inside the drying chamber was lower than ambient because of the desiccant thermal storage. Drying Limes for intermittent directs sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorbent were 55 h, 41 h, and 30 h, respectively. Specific energy consumptions for direct sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorber were 604 MJ/kg moist, 18.94 MJ/kg moist, and 13.29 MJ/kg moist, respectively. The main conclusion can be drawn here is that a solar dryer integrated with desiccant thermal storage makes drying using solar energy more effective in term of drying time and specific energy consumption. 2014 The Authors. Published by Elsevier Ltd.