Comparison of drying characteristics and quality of copra obtained in a forced convection solar drier and sun drying

Abstract

An indirect forced convection solar drier integrated with sensible heat storage material has been fabricated and tested for copra drying. It reduces moisture content (wet basis) from 52% to 7.8% and 9.5% in 66 h for trays at bottom and top respectively. System pickup efficiency varies between 45% and 13%. Copra obtained was graded as 76% milling copra grade1 (MCG1), 18% MCG2 and 6% MCG3. Specific moisture extraction rate was estimated to be 0.84 kg/kWh. In sun drying, moisture content reduced from 52.3% (wet basis) to about 9.2% in 7 days. Copra obtained was graded as 53% MCG1, 24% MCG2 and 23% MCG3. Average drier thermal efficiency of sun drying was estimated to be about 21%.