Experimental investigation on dual-shaped solar greenhouse dryer: Performance and technoeconomic analysis

Drying is essential for preserving food commodities by preventing spoilage. However, conventional drying systems are energy-intensive and heavily reliant on fossil fuels. This study focuses on the in-house design and development of novel Dual-Shaped Solar Greenhouse Dryer (DS-SGHD) for drying of food commodities. The newly developed dual-shape solar greenhouse dryer underscores on drying load/volume ratio and it has significant benefits in producing value-added dried agro products. The performance analysis, drying kinetics, specific moisture extraction rate, dryer efficiency, and technoeconomic analysis has been investigated, and compared with developed electric dryer for reference. The newly developed solar dryer was tested, the dryer maintained the temperature 15 degrees C-20 degrees C above the ambient temperature. The experiment was conducted with fresh onion having initial moisture contents of 85.9%. The time required to reduce initial moisture content of fresh onion from 85.9% to 7%, was recorded for open sun drying, dual-shaped solar dryer, and electrical dryer. The exergy efficiency range was found to be 22%-45% depending on the available solar radiation and ambient temperature. The economic evaluation was carried out using the annualized cost method, life cycle savings, and payback period method. Through the annualized cost method, the cost obtained with the DS-SGHD per kg of dried onion product was significantly lower compared to the electric dryer used. The annual saving for dual- shaped solar dryer is 36.5% more than the electric dryer used while its potential saving over the 20-year life span is 25 times more the current day investment. In general, the payback time for dual-shape solar greenhouse dryer is approximately 8-12 months. Overall, the DS-SGHD offers a sustainable, energy-efficient alternative for high-quality drying using solar energy.