| Abstract: |
In agricultural products, post-harvest losses continue to be a major problem in the developing economies mainly because of the lack of cold storage facilities and unstable electricity supply. This is an empirical research that will design, develop and evaluate a solar powered evaporative cooler that is specifically designed to store perishable agricultural products. The study combines photovoltaic systems with the direct evaporative cooling principles to develop an off-grid, cost-effective cold storage system that can be used by rural farming communities. A prototype system with storage of 2.5 m 3 was developed and tested in 120 days under different climatic conditions. The system includes a 300W solar panel set, a DC-powered evaporative cooler and thermally insulated storage chambers. Systematic monitoring and analysis of performance measures such as temperature drop, relative humidity, and energy use, and product shelf-life were performed. The findings of the experiments indicate that the system can achieve an average temperature drop of 12-15 o C below ambient temperatures, and internal temperatures of 18-22 o C and relative humidity of 85-90%. An analysis of energy consumption shows that the energy consumption is 1.8-2.4 kWh/day which is completely met by the solar photovoltaic system. Economic feasibility analysis shows a payback period of 2.8 years and benefit-cost ratio of 2.34. The results of tomatoes, leafy vegetables and fruits indicated a 8-12 days shelf-life extension over ambient storage. The significant correlation between system parameters and cooling performance is proven by statistical analysis with ANOVA and regression modeling. The research convincingly proves that solar evaporative cooling technology is a feasible, sustainable and economically viable option towards agricultural cold storage in off-grid areas, and could lead to a 40-60 per cent reduction of post-harvest losses. |
