PERFORMANCE EVALUATION OF INDIRECT TYPE SOLAR DRYER FOR DRYING HERBALS

Drying is one of the methods to preserve food item other than freezing, canning etc. During drying process the moisture content present in the food particle will be removed and it can be stored for long time. Drying has many types like open sun drying, shadow drying, oven drying and sola r drying. From the above methods solar drying is the most efficient and less expensive of drying and this way of drying can protect the food particle from rain, wind, dust, insects. In this present a simple and less expensive solar dryer can be designed an d the product chosen for drying is herbals. The conventional method of drying herbals is open drying and sometimes shadow drying for siddha and yunani treatments. The important phenomenon is the process of reduction moisture up to the safe limit of medical use. Based on the theoretical calculations, the length of the air collector is 1.5 m and width of the air collector is 0.5 m was chosen. To find the effective length and width of the solar dryer the various parameters like solar intensity, height of the c ollector and intensity of the day will be varied and calculated. The efficiency of the solar dryer for the effective area of 0.75 m? is 25.46%. By drying herbals in solar drying will provide the 3.5% more moisture.