Performance study of solar vacuum tubes type dryer

In the present work, a solar vacuum tubes type dryer is designed, fabricated, and tested for drying of different fruit and vegetable samples. The selected fruits and vegetables such as pineapple, apple, banana, guava, beans, brinjal, carrot, lady finger, and potato were dried separately by the open sun drying and by the solar dryer under consideration, and the drying efficiencies of the two methods were compared with each other. While conducting experiments on fruit samples, the solar air heater efficiency varied from 59% to 80% and the corresponding solar dryer efficiency and open sun drying efficiency were found to vary in the range of 55%–78% and 3.0%–5.0%, respectively. Similarly, while conducting experiments on vegetable samples, the solar air heater efficiency varied from 73%–84% and the corresponding solar dryer efficiency and open sun drying efficiency were found to vary in the range of 70%–79% and 3.0%–3.6%, respectively. The solar dryer reduces the average moisture content from 0.32 to 0.85 kg f...