Abstract
Evaporative cooling for food preservation is considered a passive system because it requires no external energy sources to remove heat. The underlying mechanism is the flow of air over a wetted surface. A special type of evaporative cooler is described, and results are presented from a study of cooler performance. The unit is made a galvanized zinc sheet, and wetted charcoal layers are placed adjacent to the cooler sides. Continuous wetting is provided by water supplied by an underlying valve. Analysis of different operating conditions reveals that the indoor cooler temperatures approached those of the wet-bulbs, with a difference of 10 13 degree C below ambient. While the cooler shows promise, the optimum temperature required to store perishable food has not been reached.