Development of a solar-assisted dryer and evaluation of energy requirement for the drying of onion

P.N. Sarsavadia

Renewable Energy, 2007, vol. 32, issue 15, 2529-2547

Abstract: A solar-assisted forced convection dryer was developed to study the effect of airflow rate (2.43, 5.25, 8.09kg/min), air temperature (55, 65, 75°C), and fraction of air recycled (up to 90%) on the total energy requirement of drying of onion slices. The dryer was provided with a flat plate solar air heater having both the corrugations and triangular fins to the absorber plate. For drying of onion slices from initial moisture content of about 86% (wet basis) to final moisture content of about 7% (wet basis), the energy required per unit mass of water removed during without using recirculation of air was found between 23.548 and 62.117MJ/kg water. The percent energy contribution by the solar air heater, electrical heater, and blower was found between 24.5% and 44.5%, 40.2% and 66.9%, and 8.6% and 16.3%, respectively. The savings in total energy due to fraction of air recycled were determined at 65 and 75°C air temperature for the above three airflow rates. The maximum saving in total energy up to 70.7% was achieved by recycling of the exhaust air. The energy required per unit mass of water removed was found between 12.040 and 38.777MJ/kg water. The percent energy contribution by the solar air heater, auxiliary heater, and blower was found between 22.4% and 40.9%, 33.6% and 62.6%, and 11.2% and 37.2%, respectively.

Keywords: Solar-assisted dryer; Drying of onion; Recycling of air; Energy requirement (search for similar items in EconPapers)
Date: 2007
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Citations: View citations in EconPapers (16)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:32:y:2007:i:15:p:2529-2547

DOI: 10.1016/j.renene.2006.12.019

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