Energy and exergy analyses of the solar drying processes of ghost chilli pepper and ginger

A forced convection solar tunnel dryer integrated with a shell and tube based latent heat storage module was designed and fabricated. Ghost chilli pepper and sliced ginger were successfully dried in the dryer in 42 h and 33 h in the drying air temperature range of 42–61 °C and 37–57 °C, respectively. Energy and exergy analyses of the drying processes of the two products were performed. The results showed that the thermal efficiencies of the first and the second solar air heaters varied between 22.10% and 40.24% and 9.64% and 19.50%, respectively. The average overall thermal efficiency of the air heaters array varied between 22.95% and 23.30%. The specific energy consumptions of the ghost chilli and the ginger were 18.72 kWh/kg and 8.82 kWh/kg, respectively. When the ghost chilli was dried, the exergy efficiency of the drying chamber was in the range of 21%–98% with an average of 63%, and it was 4%–96% with an average of 47%, while the ginger was dried. The exegetic efficiency increased with advancing in drying time, and high exergetic efficiency was recorded in the last few hours of the drying operation of the consecutive drying days.