Development and performance evaluation of passive evaporative cooling system for tomato storage application

Tomatoes require immediate postharvest cooling due to higher perishability and associated losses. The situation becomes worsen in resource-constrained areas/farms as half of the tomatoes production may lost due to the losses. In this regard, a passive evaporative cooling-based tomato storage system (PEC-TSS) was developed and thermodynamically evaluated under different experimental conditions. Physicochemical analyses of tomatoes stored in PEC-TSS, outside, and room conditions were also performed to assess the comparative shelf-life. The PEC-TSS enabled a higher temperature drop about 11–14 °C, and maintained relative humidity above 85%. The corresponding average cooling efficiency, cooling capacity, exergy efficiency, temperature-humidity, and sustainability indices were determined as 80%, 2.1 kW, 26%, 31 °C, and 1.36, respectively. The titratable acidity and soluble solids of tomatoes retained 0.2 mg/g and 5°Brix, respectively, in the PEC-TSS. The physiological weight loss was measured about 20% for PEC-TSS-stored tomatoes compared to above 80% in other storage conditions. Therefore, the shelf-life of PEC-TSS stored tomatoes was extended to about 37 days under particular load conditions. The payback period of marginal-scale PEC-TSS was calculated about two years, with cost-benefit ratio greater than 1.0 from the second year to onwards.