Background
The performance of a solar tunnel dryer for drying ginger was investigated through a series of experiments. Two axial flow fans with a power rating of 28W, supply voltage of 220V, and powered by a 50W PV module were used to supply hot air to the drying chamber.
Results and discussion
The dryer has been put through no-load and load tests with solar PV powered fans. Solar radiation, dry air temperature, ambient temperature, relative humidity (RH), and air velocity were recorded at five solar tunnel dryer positions by dividing the 8.5-meter-long solar tunnel dryer into four equal parts every thirty minutes. When the solar radiation was altered between 540 and 820 W/m2, the hot air temperature at the collector output rose from 34°C to 65.5°C for an 8-hour operation in the no-load state. At loading operation circumstances, average maximum temperatures of 30°C at 9:00 AM and 77°C at 13:00 PM were achieved. In 24 hours (3 solar days), the solar tunnel drier was able to reduce the moisture content of sliced ginger from 90.4 % to 11.8 percent (wet basis). Open sun drying, on the other hand, takes 40 hours (5 solar days) to obtain the same wet basis condition. With a solar collector area of 6 m2.
Conclusions
Eight experiments have been conducted at no-load and full-load conditions. The drying air temperature varied from 34.0°C to 65.5°C at the collector outlet. The drying time decreases as the collector area increases, whereas the drying efficiency and time savings increase. Furthermore, the gingers were totally sheltered from rain, insects, and dust while drying in the solar tunnel dryer, resulting in high-quality dried gingers. The dryer could be utilized in rural locations where there is no access to energy because the fans are driven by a solar module. The solar tunnel dryer showed a net saving in drying time of 40% over open sun drying.