Performance evaluation of natural and forced convection indirect type solar dryers during drying ivy gourd: An experimental study

Abstract

The performance investigation of natural and forced convection indirect type solar dryers was performed by drying ivy gourd. The natural convection setup was modified by fitting a trapezoidal duct and central processing unit fans run by photovoltaic panels to promote forced convection. The data from the experiment was used to estimate collector and dryer efficiencies, energies, effective moisture diffusivity, transfer coefficients, specific energy consumption and specific moisture extraction rate. The average actual heat supplied was 776.6 and 997.76 W for natural and forced convections, respectively. The average collector efficiency for the same was 62.56% and 77.2%, respectively. The average drying efficiency for the same was 6.62% and 7.8%, respectively. The average values of activation energy, mass transfer, heat transfer and diffusion coefficients were estimated to be 39.85 and 35.54 kJ/mol, 7.06 × 10−9 and 8.35 × 10−9 m2/s, 0.0033 and 0.0043 m/s, and 3.85 and 4.93 W/m2 K, respectively, for natural and forced convection setups, respectively. The specific energy consumption and specific moisture extraction rate were evaluated where forced convection setup gave the best results. The drying correlations were developed for mass transfer, heat transfer and diffusion coefficients. Uncertainty analysis was performed to check the authenticity of the results.