Vol. 7, Issue 5, Part F (2025)

Solar dryers have potential to preserve various agricultural commodities. All the existing dryer has a common limitation of constant energy production and distribution in plenum chamber. The optimum temperature required for drying a commodity with superior quality is 70°C. Depending upon the availability of solar radiation (Global and Beam, W/m²), relative humidity (ϕ, %) and air flow rate (m³.s^-1), the area of heat collecting source is determined. This technology is one of the prime and green renewable sources of energy. It is abundantly available over the surface of the earth with maximum day length in summer and minimum day length in winter seasons. Due to intermittent nature of solar availability, the energy produced is non-uniform and irregular, hence introduction of Phase Change Material (PCM) in the field of solar dryers helped to produce uniform temperature throughout the drying period. Organic PCMs are observed to be non-corrosive, chemically stable and exhibit little or no sub-cooling. Inorganic PCMs have the advantageous of high latent heat per unit volume, high thermal conductivity and are non-inflammable. Among various available PCM, Neo-pentyl-glycol (NPG) and Tris (hydroxymethyl) Amino-Methane (TRIS) are promising PCMs for heat storage system applications. The major fringe benefit of applying PCM is that drying time could be extended to off sunshine hours which help in performance enhancement of the developed solar dryer. Hence, the present review was focused on the novel application of thermal storage system using Phase Change Material (PCM) integrated solar air heater for drying of agricultural commodities with consistent heat generation and distribution inside the drying chamber.