Performance analysis of rack type solar dryers with mass variations of dried material and types of fins

The purpose of this study was to determine the performance of solar dryers based on effect of variations on mass of dried material and effect of types of fins. The air flow in the solar dryer is a natural convection. Solar dryers used in this study were four solar dryers of rack type which has three stacking shelves with different type of fin respectively. Testing method that used was direct simultaneous testing. The material that was dried was corn. Testing of the first day was conducted with an initial material mass of 500 grams/rack while the second day used 900 grams/rack. Testing were conducted in the city of Makassar, South Sulawesi, Indonesia, from 10:00 am until 16:00 pm. Testing with the initial mass of material of 900 grams/rack had greater drying rate and efficiency but the decline in water content was lower than the testing with initial mass of material of 500 grams/rack. Based on the decrease in water content, drying rate and efficiency, the use of a large wave fin had the best performance and almost the same with the zigzag fin. The use of a small wave fin had the lowest performance while the plate fin slightly better than the small one. (paper)