Design, construction and evaluation of a passive evaporative coolant for on-farm storage of freshly harvested tomatoes

Abstract

A simple structure capable of being used for on-farm storage of freshly harvested tomatoes was designed, constructed and evaluated on a tomato farm in the Ada District in Greater Accra Region. The storage structure in the form of an improved maize crib measured 2.13 m long by 1.83 m wide and with a height of 2.28 m. The storage unit which works on the principles of evaporative cooling was constructed out of simple and cheap local materials. It was able to achieve a relative cooling of 3.7ᵒC and increase in humidity of 13.2%, within the structure. These were at average ambient condition of 30ᵒC and 72.3% relative humidity. The storage structure was able to extend the shelf life of nearly 200kg of medium-sized tomatoes (Heinz var. 1409) by 5 days. The structures can be used to temporarily store tomatoes and other perishables before arrival of vehicles to convey them to the main marketing centres