ABSTRACT

An evaporative cooling system was designed, fabricated and tested for the storage of fresh fruits and vegetables. The system's working principles is based on the principle of evaporation which causes a cooling effect to its surrounding. The system is an enclosed system and air is allowed to pass only through the pad, also a suction fan centrally located which draws in air through the pad. Water drips into the foam at a constant rate through a water distribution system. As the water drips into the foam the suction fan draws warm air through the wetted pad. During this process the warm air which is the sensible heat passes through the wetted pad which is now changed to latent heat due to the evaporation that has occurred as a result of the water being evaporated which causes the cooling within the enclosure with the achievement of a temperature difference of about 14.1°C.The excess water drops down to the trough or water collector. As the excess water is stored at the water collector, the circulating pump is used for circulating the water back to the water reservoir. The materials for construction were selected based on the type of produce to be stored, availability, nearest to market, durability and economic consideration. Some of the materials included are; suction fan, pad end, water reservoir, pipe, water pump, water collector/trough. The system was tested for storing some fresh tomatoes for seven (7) days. Test result showed that the Evaporative Cooling System (ECS) is more efficient and sustainable means of storing fresh fruits and vegetables. From the result of the test, it can be deduced that the cooling efficiency was found to be 81.9% and the average temperature of the Evaporative Cooling System (ECS) was 14.1°C while the average ambient temperature was found to be 25.6°C. With the production cost of seventy-four thousand three hundred Naira (N?4,300), the system can easily be afforded by small holder's farmer who are the intended users.