Design and fabrication of a DC pump evaporative cooling system

The design, fabrication and evaluation of an evaporative cooling system was carried out. The system was cabinet was constructed with 1 mm thick aluminum sheets and jute wetted by water flowing by gravity through a series of perforated 25mm diameter pipes from a 60-liter capacity reservoir located at the top of the storage system. The cooler has 4 trays. A 0.5 horse power pump was installed for pumping water to the overhead reservoir. As evaporation took place, the temperature in the system dropped drastically from 24.6 to 30.5°C and the relative humidity in the cooling chamber increased to 97.5% compared to ambient relative humidity value of 58.9%. However, the testing of the evaporative cooling system shows that the tomatoes can be stored for an average of five (5) days with negligible changes in weight, color, firmness and rotting as compared to ambient condition which started rotting after four (4) days. The average cooling efficiency was 87.6%.