Solar powered evaporative cooled storage structure for storage of fruits and vegetables

Abstract

A solar powered evaporative cooled storage structure (ECSS) was designed and developed for storage of fresh fruits and vegetables to increase their shelf-life. The structure consists of a solar powered exhaust fan and cooling pump for providing water to the pads. Cooling pads of different materials such as wood shaving, khas and celdec were used. The system works on the principle of a simple desert cooler. The pads are wetted with the help of circulating water through a solar powered pump and an exhaust fan sucks the cool air through the pads of the structure. The areas for the cooling system considered were 2.25 m2, 4.5 m2, 6.75 m2 and 9 m2 respectively. The results showed that under the no-load condition, the average air cooling efficiency was highest for CELdek at 78.67%, compared to 73.82% for wood wool and 70.75% for khas pad material and the maximum difference in relative humidity (RH) and dry bulb temperature between ambient and inside the cooler was 59% and 14.6°C when these materials were used in all four sides in the ECSS. This environment helped in keeping the vegetables fresh for significantly more time. This is very useful in rural areas where there is shortage of electricity or its supply is erratic for storage of fresh fruits and vegetables.