Potential of integrating Na₂SO₄ · 10H₂O pellets in solar drying system

ABSTRACT

In the current study, evolution of thermophysical properties of red chilli dried in a mixed mode solar dryer that integrates sodium sulfate decahydrate (Na₂SO₄ · 10H₂O) and sodium chloride (NaCl) as thermal storage were presented. Solar drying with Na₂SO₄ · 10H₂O reduced the drying time by 26.7 and 39%, compared to the drying time with or without NaCl. Dimensional shrinkage was gradual with a nonlinear exponential shape for the whole drying conditions. The evolution of the bulk and particle densities decreased while the porosity of the seed increased with time. The coefficient of heat and mass transfer varied from 0.0036 − 0.035 W/m² K to 6.09 × 10⁻⁹ − 6.2 × 10⁻⁸ m/s, respectively. The thermal conductivity, specific heat capacity, and thermal diffusivity ranged from 0.0568 to 0.1093 W/m K, 1,072 to 2218.7 J/kg K, and 4.7 × 10⁻⁵ to 5.13 × 10⁻⁵ m²/s, respectively.

KEYWORDS:

• Desiccants
• heat transfer coefficient
• mass transfer coefficient
• pepper
• phase change material
• shrinkage