A solar tunnel dryer having 16 meter long and 2 meter width was designed and constructed to dry about 300 kg of freshly harvested limes per batch. The nearly one-third area of the tunnel base was used as the solar collector and the remaining two-third area as a dryer. The drying temperature could be easily raised by some 5-300C above the ambient temperature inside the tunnel at an air velocity of approximately 0.15 (ms-1). The test was conducted with about 300 kg freshly harvested limes with initial moisture content of 86.0% (wet-basis) to analyze the performance of the dryer. The limes were dried to a final average moisture content of 10.0% (wet-basis) within 7 days (70 hours). The results indicated that the drying was faster in solar tunnel dryer ( 7 days) than the natural open air sun drying (> 3o days). The improvement in the quality of limes in terms of color, brightness and flavor was distinctly recognized.

A solar tunnel dryer having 16 meter long and 2 meter width was designed and constructed to dry about 300 kg of freshly harvested limes per batch. The nearly one-third area of the tunnel base was used as the solar collector and the remaining two-third area as a dryer. The drying temperature cou...