Design, Construction and Testing of a Passive Evaporative Cooler for Short-Term Preservation of Fresh Tomatoes

A passive evaporative cooler for short-term storage of fresh tomatoes was designed, constructed, and evaluated. The system employed jute bags as the cooling pad, with water circulated from overhead and base pans. The cooler consistently reduced internal temperatures by 3–5 °C and increased relative humidity by 5–10% compared to ambient conditions. Maximum relative humidity of 73% was achieved, approaching the recommended range for tomato storage. Shelf life was extended to 16 days, compared with 10 days under ambient storage. These results demonstrate that a low-cost, passive evaporative cooler can effectively prolong tomato freshness under tropical conditions, offering a sustainable alternative for smallholder farmers