SOLAR DRYING OF MANGO USING SOLAR TUNNEL DRIER

摘要

This study was conducted to investigate the performance of the solar tunnel drier for drying mango underBangladesh conditions. The drier consists of a transparent plastic covered flat plate collector and a drying tunnelconnected in series to supply hot air directly into the drying tunnel using two dc fans, operated by a solar module.This drier has a loading capacity of 120-150 kg of mango and a total of 9 drying runs were conducted. Drying airtemperature at the collector outlet varied between 35.6 ℃ to 53.5 ℃ in the month of July and August, 1999 and35.9 ℃ to 56.7 ℃ in the month of June and July, 2000. In all the cases the use of solar tunnel drier leads toconsiderable reduction of drying time in comparison to sun drying. The mango being dried in the solar tunnel drierwere completely protected from rain, insects and dust, and the quality of the mango dried in the tunnel drier was ofquality dried products as compared to sun dried products. Proximate analysis also indicates that the mango dried inthe solar tunnel drier is a good quality dried product for human consumption. The drier is simple in construction andcan be constructed using locally available materials by the local craftsman. The solar tunnel drier can be operated byone photovoltaic module independent of electrical grid. The photovoltaic system has the advantage that thetemperature of the drying air is automatically controlled by the solar radiation.