Title : Techno-economic analysis of a hybrid solar thermal-biogas powered dryer for fruit dehydration
Abstract:
As of 2024, the global population had reached 8.2 billion and is expected to grow by 2 billion in the next 30 years, raising concerns about food security. Reducing post-harvest losses, which account for nearly one-third of global food waste, is critical, especially in developing countries. This study evaluates the techno-economic feasibility of a hybrid solar thermal-biogas drying system to enhance efficiency and sustainability in fruit drying. The research involved designing and simulating a hybrid tray or cabinet dryer to address challenges of intermittency and continuity in traditional drying methods. Simulations were conducted using SolidWorks while the experimental design followed the Box-Behnken methodology in Design Expert software. Optimized parameters included an air velocity of 2 m/s, material thickness of 7.5 mm, temperature of 60 °C, and a final moisture content of 10.5 %. A prototype was built and tested, showing significantly shorter drying times of 9.8 hours and increased capacity compared to open sun drying. The hybrid system achieved a moisture removal rate of 78.3 %, surpassing the 42.3 % rate of sun drying. Financial analysis showed a return on investment (ROI) of 68.01 %, a net present value (NPV) of USD 321, and a simple payback period of 1.47 years thus outperforming open sun drying with an ROI of 28.0 %, NPV of USD 1.6, and a simple payback period of 3.57 years. Sensitivity analysis indicated that revenue fluctuations and operational costs significantly impact financial viability. A 10 - 20 % revenue drop, or a 10 % cost increase extended the simple payback period and reduced ROI and NPV. The hybrid system presents a sustainable and cost-effective drying solution. Further research on different crops, environmental conditions, and industrial scaling is necessary.
Keywords: Solar thermal; biogas; fruit drying; Hybrid dryer; modeling and simulation; techno-financial analysis.
