Modification and Performance Evaluation of Modified Natural Circulating Solar Dryer

The use of solar energy in recent years had reached a remarkable edge. It had become even more popular as the cost of fossil fuel continues to rise. A study was undertaken to develop a natural circulating solar dryer and evaluate its performance with Open sun drying. The drying experiments were carried out at lab VSAET, SHIATS Allahabad. The performance of the dryer was evaluated by drying samples of potato. This solar drying system consisting of two parts, solar collector and solar drying cabinet. In this experiment two solar collector were joined in series. Solar collector with area of 0.97 m2 (1.06 m x 0.91 m x 0.19 m) had placed black marble, area of marble 0.64 m2 (0.76 m x 0.84 m), angle of frame was 370 and float glass of rectangular shape had thickness 0.008 m to absorb solar radiation and there are 4 hole in each collector it size was 0.075 m. A cabinet that was divided into two divisions separated by two removable shelves. Each shelf was 0.36 m width and 0.53 m length and made of wire mesh framed. Three sides of the drying chamber walls were covered by tin sheet (0.0011 m) and a door in the back. The highest temperature inside the cabinet significantly elevated compared to environmental air with temperature increases of up to 55°C and 66°C depending on air flow and loading. Loading tests conducted with an average of 100g of potato slices resulted in effective drying within one days from a moisture content of 86.8% (wb) down to approximately 1.02% (wb) for modified natural circulating solar dryer of operation respectively. These results indicated sufficient drying and preservation of potato slices within one day of sunlight. It was found that the dryer was suitable for drying of potato slice.