Abstract The use of solar resource for food drying has always been a food preservation technique which has widely been practised in most parts of the world. The solar drying system utilizes solar energy to heat up air and to dry food substance placed in dryer, which is beneficial in reducing wastage of food products and helps in preservation of the same. Unfortunately, some of the methods practised in the rural areas have many disadvantages, one of which is the poor quality of food dried. The paper looks at bringing out a new modified design of a solar dryer, which combines the concept of mirror reflectors for better solar insulation and chimney for creating stack effect for better air movement. The ideas of flat plate and curved surface area and exhaust fan have also been explored. The system is designed for increasing the drying rate of the dryer and removing maximum possible moisture contents. The dryer is designed primarily as an indirect type passive solar dryer. The indirect type passive dryer has an advantage that the products are being protected from the UV radiation and there is less damage from temperature extremes; because in these types of dryers, food is placed in trays without sun exposure in the drying cabinet. Our aim has been not only to improve the performance of dryer but we want some better food products. The results obtained during the test period revealed that the temperatures inside the dryer and the solar collector were much higher than the ambient temperature during most sunshine hours. As a result, we got the collector temperature and dryer temperature higher with mirror reflectors than without mirror reflectors. The drying rate was also increased with mirror reflectors than without mirror reflectors and open drying. The variation of surface area of the absorber plate is also analysed in this paper and the effect of incorporating exhaust fan in the system has also been discussed. The results from this paper will go a long way in solar drying technology and preservation of food products in rural areas of India. Keywords: Solar drying, drying rate, passive dryer, collector areaCite this Article Harshita Badal, Ankita Badal, Usha Bajpai. Thermal Performance Analysis of a Solar Dryer-cum-Air Heater with Modified Absorber Surface. Journal of Thermal Engineering and Applications. 2016; 3(3): 34–40p.
