Assessment of a Cowl-Incorporated Wind-Powered Forced-Air Evaporative Cooler for Preservation of Fruit and Vegetables

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This paper reports the performance of a cowl-incorporated wind-powered forced-air evaporative cooler for preservation of fruit and vegetables. The evaluation took place in the Department of Mechanical Engineering, Obafemi Awolowo University, Ile-Ife in October. Freshly harvested tomatoes were used in the evaluation as tomatoes were common locally and are highly perishable. The produce (2.5 kg) was kept in the cooling chamber of the evaporative cooler, and the changes in weight were observed three times daily until the produce had lost more than 7 % of its weight. The no-load cool air temperatures ranged between 27.3and 34.5oC corresponding to ambient dry bulb temperatures 29.0and 43.9oC respectively. The no-load cool air relative humidity ranged between 63.0 and 87.2% corresponding to ambient relative humidity of 40.8 and 79.5% respectively. The evaporative cooler no-load cooling efficiency was 66.7% while the cooling efficiency when loaded was 50.0%. The evaporative cooler was able to preserve tomatoes for 9 days losing 4.8 % weight. The evaporative cooler had the potential of effectively preserving fruit and vegetables without dependence on electricity. If used in windier and less humid regions, the average cooling efficiency of the evaporativecooler would be higher than that observed in this research.