C. B. Joshi and R. C. Bhandari
Institute of Engineering, Tribhuvan University,
Pulchowk, Lalitpur, Nepal

DOI

ABSTRACT

Various types of solar dryers have been developed and experimented within the country but their applications are still limited due to several problems associated with them. An Innovative Solar Rack Dryer (ISRD) has been developed in this study as an attempt to mitigate some of the technical problems. The study deals with detailed design and fabrication of an ISRD having a drying capacity of 4 kg/batch of fresh Cauliflower. The dryer (2.27m × 0.9m × 0.48m) consists of two solar collectors having total area of 1.65m2, four trays (each of 0.14m2) inside the drying chamber, a deflector just below the lower row of trays to distribute hot air uniformly throughout the drying chamber, a radiation distributor just below of upper collector to radiate heat flux uniformly throughout the trays of upper row, a sliding gate to control the airflow at the air inlet passage of collector and a chimney (340mm × 110mm × 150mm) for air outlet at the top of drying chamber. The whole unit is supported by a stand of height 1.06m. The intensive testing revealed that dryer had an efficiency of up to 21.4 per cent. Uniform drying of materials throughout each tray has been obtained.