Fabrication and Performance Evaluation of Solar Tunnel Dryer for Ginger Drying

Abstract

A series of tests were conducted to investigate the performance of a solar tunnel dryer for drying ginger. To supply hot air to the dryer, two axial flow fans with a power rating of 28 W, a supply voltage of 220 V, and a 50 W photovoltaics (PV) module were employed. By dividing the 8.5-meter-long solar tunnel dryer into four equal portions every thirty minutes, solar radiation, dry air temperature, ambient temperature, relative humidity, and air velocity were measured at five solar tunnel dryer stations. The hot air temperature at the collector output grew from 34°C to 65.5°C for an 8-hour operation in the no-load condition when the solar radiation was changed between 540 and 820 W/m2. At 9:00 a.m., the average maximum temperature was 30°C. During the loading operation, the temperature was 77°C at 1:00 p.m. The moisture content of sliced ginger was reduced from 90.4 to 11.8% on a wet basis using the solar tunnel dryer. With a solar collector area of 6 m2, open sun drying takes 40 hours to achieve the same wet basis condition. A total of eight experiments were carried out, both with and without loads. The dry air temperature at the collector outlet ranged from 34.0 to 65.5 °C. As the drying efficiency, collector area, and time savings improve, the drying time decreases. The ginger is kept in a controlled area, resulting in high-quality dried ginger. The solar tunnel dryer showed a net saving in drying time of 40% over open sun drying.