LAUSR

Solar drying is one of the most feasible and cheap method in preservation of foods and commodities. An experimental analysis was performed on a solar tunnel dryer under the meteorological conditions of Negamam, India, for drying samples of Vitis vinifera and Momordica charantia. Sand bed, rock bed and aluminum filings were used as thermal storage materials for the study. A comparison was made between the dryer (with and without the application of thermal storage materials) and open sun drying to check the effectiveness in dehydrating the samples. There were effective reductions in drying time as well as moisture removal rate (85%–10% in 27 h and 88%–6% in 6 h) using the solar tunnel dryer (with or without thermal storage materials) as compared with open sun drying. Average thermal efficiency of the solar tunnel dryer with thermal storage materials was found to be greater by 2–3% as compared with the one without thermal storage material. Amongst the thermal storage materials, sand was found to have higher effectiveness with an average thermal efficiency of 19.6% and 15.46% while drying Vitis vinifera and Momordica charantia respectively.