Drying of Mango using Solar Tunnel Drier

Abstract

Field level experiments on solar drying of mango using solar tunnel drier were conducted at Chapai Nawabganj, Bangladesh. The drier consisted of a transparent plastic covered flat plate collector and a drying tunnel connected in series to supply hot air directly into the drying tunnel using two dc fans, operated by a solar photovoltaic module. This drier has a loading capacity of 120-150 kg of mango. A total of9 drying runs were conducted. Drying air temperature at the collector outlet varied from 35.6 °C to 53.5 °C in the months of July and August, 1999 and 35.9 °C to 56.7 °C in the months of June and July 2000. The temperature inside the collector increased along the length of the collector from the inlet of the collector while the drying air temperature was almost constant throughout the drier length during drying of mango. The moisture content of the sulphur treated mango of a typical experimental run reached 13.47% from 78.87% in 3 days of drying in the solar tunnel drier while it took 3 days of drying .to bring down the moisture content of similar sample to 22.48% in traditional method. Proximate analysis indicated that the mango dried in the solar tunnel drier was a good quality product for human consumption.