Performance evaluation of evaporative cooling systems for mitigating post-harvest losses in Ethiopian horticultural crops

Abstract

This study investigates the design, development, and evaluation of an integrated evaporative cooling system to mitigate post-harvest losses of horticultural crops in Ethiopia. The system combines direct and indirect evaporative cooling techniques to improve efficiency and adaptability in various climatic conditions, particularly in hot and arid regions. The experimental setup was tested under different environmental conditions, with ambient temperatures ranging from 35°C to 42°C. The results indicate that the integrated system can reduce the temperature inside the storage unit by up to 10°C below the ambient temperature, achieving relative humidity levels of approximately 90%. This creates an optimal environment for preserving perishable goods. In field tests, the system significantly extended the shelf life of tomatoes, one of the primary focus crops. After 6 days of storage, tomatoes kept in the evaporative cooler experienced only a 5% weight loss, compared to an 80% weight loss for tomatoes stored under traditional open-market conditions. These results highlight the system’s effectiveness in maintaining the quality of perishable produce. The study also compares the performance of the integrated system with a direct evaporative cooling system. While the integrated system shows a slight performance advantage under optimal conditions, it is particularly beneficial in more extreme environments, such as Ethiopia’s lowland regions, where pre-cooling the air substantially enhances cooling efficiency. The findings suggest that this integrated evaporative cooling system offers a viable and energy-efficient alternative to conventional refrigeration, particularly in developing countries.