Effect of Phase Change Materials on the Performance of Natural Convection Indirect Type Solar Dryer during Drying Ivy Gourd

Abstract

The effect of integrating thermal energy storage (TES) unit with a natural convection indirect type solar dryer was investigated by drying ivy gourd in the dryer without TES (setup I) and with TES (setup II) provisions. Paraffin wax was filled in the concentric tubes of polycarbonate and finned aluminum to make setup II by updating setup I. The experimental data from both setups were used to estimate the drying parameters. The average collector's efficiencies were 62.6% and 63.3%. Drying efficiencies were 6.6% and 13.1% for the setup I and II, respectively. The average moisture diffusivity, mass transfer and heat transfer coefficients were 7.1 × 10−9 and 8.1 × 10−9 m2/s, 0.0033 and 0.0041 m/s and 3.9 and 4.7 W/m2K for the setup I and II, respectively. The enhancements of drying efficiency, effective diffusivity, mass and heat transfer coefficients were 98.3%, 14.2%, 24.2% and 22.1%, respectively, in setup II compared to setup I. The activation energy, average specific energy consumption, and specific moisture extraction rate were evaluated. The drying kinetics were correlated with time and moisture variations. It took 18 and 16 h to reduce the moisture content of the sample from 15.32 (db) to 0.144 (db) for the setup I and II, respectively.