Design of Semisphere Solar-Microwave Hybrid Dryer and Drying Performance of Zucchini

Abstract

In this work, performance of a newly designed hybrid dryer was investigated. Drying was done with the support of solar energy to microwave conveyor dryer. By using collector, which was designed with semisphere shape for having high efficiency from solar energy, hot air was produced and moved through the tunnel with velocity of 3 m s(-1) and by using 0.7, 1 and 1.4 kW microwave support, drying behavior of 5, 10, and 15 mm zucchini slices were examined. At the end of drying process, drying time, color changes of dried products, energy consumption, collector efficiency, and modelling of drying were determined. Considering the time required for drying the zucchini slices until reaching 10 +/- 1% (wb) moisture content and electrical energy consumption values, the most suitable results were obtained from 1 kW microwave power, air velocity of 0.245 m min(-1) , and 5 mm zucchini slice thickness, corresponding to total energy of 1.143 kWh. The collector efficiency was calculated as 24.3%, under the environmental conditions of our study.