Development and Evaluation of a Solar Thermal Collector Designed for Drying Grain

Abstract: The present research study is on development and performance evaluation of a solar thermal collector that warms up air as transferring medium of heat for drying of grains. A 6 meter long, 4 meter wide and 0.3 meter thick solar thermal collector was constructed in which a V-corrugated steel sheet was used as absorber and a 6 mm thick glass used as glazing. The collector body was fabricated from plywood. The solar thermal collector is linked with a 4 meter high grain storage bin having a diameter of 2 meter. Performance of this collector was evaluated from November 2011 to January 2012 at seven different convective flow rates of air (7.5, 14.16, 28.30, 56.6, 112.2, 168.5 and 224.4 kg.h). The statistical analysis showed that increase in mass flow rate significantly1 (P> 0.003) increases the performance of the solar collector. Also there was decrease in performance by the change of months of year. The efficiency was 10 % higher in November 2011 as compared to January 2012. It was concluded that for drying of grains the solar thermal collector must be operated at high mass flow rates of air from 9:00 am to 4:00 pm to get maximum performance from the solar thermal collector used for grain drying. Key words