IMPACT OF DRYING TEMPERATURES AND AIR MASS FLOW RATES ON THE DRYING PERFORMANCE OF A PARABOLIC TROUGH SOLAR COLLECTOR (PTSC) USED FOR DEHYDRATION OF APRICOTS

Abstract

An efficient parabolic trough solar collector (PTSC) was developed from locally available materials and used for dehydration of apricots. The apricots were cut into two halves and dried after pre-treatment of 1% with sodium benzoate solution. Apricots were dried at temperatures of 40, 50 and 60°C under three different air mass flow rates of 1.57, 2.29 3.56 kg.min-1 at less than 30% humidity Shortest apricots drying time was 16 hours at 60°C temperature and air flow rate of 3.56 Kg.min-1 with an average drying rate of 0.035 g.hr-1 .cm-2 .. It was followed by drying time of 19 hours at 55°C. The air mass flow rate was 2.29 Kg.min-1 with an average drying rate of 0.29 g.hr-1 .cm-2 . Initial moisture content of the apricots was 86% which reduced to less than 10% after drying. Results showed that both air mass flow rates and drying temperatures significantly (P< 0.000) affected efficiency, moisture lost, drying rate and drying time. The PTSCs must be operated at high temperatures and high air mass flow rates to achieve maximum performance. Apricots must be dried at high temperature and high air mass flow rates to get minimum time for getting valuable dried apricots.