Experimental Comparative Study on Reduction in the Moisture Content of Cucumber in a Double Slope Solar Dryer with Open Sun Drying Method

Abstract

In this paper, a double slope natural convection based solar dryer was constructed at the terrace of the science block, NIT Puducherry, Karaikal. The reduction in the moisture content of the samples in the double slope natural convection based solar dryer was experimentally investigated for Karaikal climatic conditions (Karaikal, U.T of Puducherry, India; 10° 55' N, 79° 52' E). In order to investigate the green vegetable, cucumber was considered for this purpose. To compare the effect of double slope solar dryer on drying vegetables products, the same green vegetable, cucumber was also dried adjacent to the system by open sun drying process. Experiments were carried out from 10.30 am to 5.30 pm on 24th February 2018 to measure the dryer air temperature, surface temperatures, and the percentages of the wet basis moisture content are measured at regular intervals of every one hour. In the experiments, it was found that the developed double slope solar dryer removed the maximum wet basis moisture content of 93.93% from the cucumber sample and based on open sun drying method, 88.03% the wet basis moisture content is only removed. Also, at the end of the experiments (5.30 pm), the weight reduction achieved in open sun drying (75 grams) was achieved in the solar dryer by three and half hours prior to that. Thus, the rate of drying in solar dryer is more compare to the open sun drying. Thus, the developed solar dryer system can be effectively used for the purpose of drying the vegetable products.