Comparative Performance Analysis of Chimney Assisted Greenhouse Solar Dryer and Open Sun Drying of Cereal Crop

Abstract

This research presents the comparative thermal analysis of chimney assisted greenhouse solar dryer and open sun drying. Recognizing the critical role of solar drying in minimizing post-harvest losses within sustainable agriculture, prototype was developed in my PhD thesis work at AKS University, Satna (MP), India. The structures was engineered using MS steel angle frames and glazed with 200-micron polyethylene sheets to maximize the greenhouse effect, integrated with an attached chimney to induce a natural draft for enhanced ventilation. The investigation monitored key performance indicators at one-hour intervals, including solar irradiance, air velocity, relative humidity, dryer temperature, and crop moisture content. Experimental results demonstrated that the greenhouse effect significantly elevates the internal chamber temperature, confirming the dryer’s superior thermal capability. The findings suggest that this chimney assisted design provides an efficient, low-cost solution for improving drying rates and maintaining crop quality in agricultural processing. Thermal analysis revealed that the greenhouse solar dryer achieved a peak internal temperature of 38°C, significantly higher than the ambient temperature of 25°C. Drying trials conducted on paddy showed a reduction in moisture content from an initial 18.2% (wb) to a final 13% (wb) within the chimney assisted system. In comparison, traditional open sun drying only reduced the moisture content to 16.3% (wb) over the same period, highlighting the superior drying efficiency of the chimney-assisted greenhouse design. Design geometry and chimney height accounted for a 13°C temperature increase above ambient levels during trials conducted in Satna (MP) in December 2022.