Experimental and Thermodynamic Analysis of Exergy, Energy, and Carbon Dioxide Emission During Hybrid Solar Drying of Strawberry

Abstract In the present study, the exergy and energy efficiencies were evaluated experimentally and thermodynamically to examine the thermal performance of the hybrid double-pass collector solar dryer during the strawberry drying. An auxiliary electrical source was used to prolong the drying process during energy deficit. Temperatures inside the dryer and ambient air, solar radiation intensity, and strawberry weight loss were monitored during the drying process. In the hybrid indirect solar dryer, strawberries reach a moisture content of 11.87% (wet basis) in 8.5 h on the lower tray, and the same (8.5 h) is required for open sun drying. At the same time, the moisture content in the upper tray is slightly higher at 13.87%. The average drying rate is the highest in the case of open sun drying and reaches 0.57, 0.59, and 0.77 g/min for open sun, lower tray, and upper tray. The average effective diffusivity of the strawberry obtained reaches values of 2.04 × 10−9, 1.98 × 10−9, and 1.79 × 10−9 m2/s for open sun, lower tray, and upper tray of the hybrid solar dryer, respectively. The average exergy efficiencies reach 2.4%, 73.82%, and 17.48% for the solar collector, drying chamber, and drying process, respectively. Using solar dryers instead of grid-based electricity, diesel, and coal-powered dryers will reduce carbon dioxide emissions by approximately 0.229 tons/year, 1.72 tons/year, and 57.21 tons/year, respectively. Additionally, this switch will save 5.63 kWh of energy per day.