Design and Performance Evaluation of an Active Solar Dryer for Cinnamon Quills

Abstract

Sri Lanka is the largest producer of true cinnamon in the world, accounting for about 60-70% of the global production. Cinnamon quills should be dried properly to contain less than 15% moisture to obtain a long shelf life. Air drying is one of the oldest methods of food preservation where the products such as cinnamon are dried without exposing directly to the solar radiation. But this method has many disadvantages such as spoilage of products due to rain, wind, dust, insect infestation, animal attack and fungi. Therefore it is essential to introduce solar dryer for the drying of cinnamon quills properly to supply high quality cinnamon to the market The aim of the study was to design and to compare the performance of an active solar dryer for cinnamon and with the performance of existing shade drying technique. The dryer is composed of solar collector, drying chamber, plenum chamber. Ten kilograms of cinnamon quills were placed in the dryer and open shade drying system separately and, performance parameters were evaluated during one hour intervals. Initial average moisture content of the quills was 59 % and it was dropped to recommended safe moisture level (15%) with in 20hrs by solar dryer while open sun drying 36hrs to reach safe moisture level. Temperature inside the drier was higher than the ambient temperature and corresponding relative humidity in the drier was lower than ambient relative humidity Maximum drying efficiency of 52% was obtained during the peak sunshine hours and lowest efficiency of 31% was obtained during the initial stage of the experiment. As a result, drying rate of quills in a force convection drier was found to be higher than that of open shade drying.