PERFORMANCE OPTIMIZATION OF A SOLAR-POWERED EVAPORATIVE COOLING SYSTEM

Abstract

Fruits and vegetables are important sources of digestible carbohydrates, minerals and vitamins A and C. For maximum usefulness and optimum nutritive value, fruits and vegetables are usually consumed when they are fresh and fully matured and harvested. The research work aimed to determine the optimum cooling conditions in a solar-powered evaporative cooling system for maximum preservation of fruits and vegetables. A three-factor, five levels Central composite rotatable design (CCRD) of response surface methodology (RSM) was employed to determine the optimal cooling condition with respect to the three main cooling parameters such as water flow rate), pad thickness and air velocity. The highest cooling efficiency of 80.8% was obtained at water flow rate of 2.5 L/min, pad thickness of 60 mm and air velocity of 1.7 m/s. The optimization of the cooling parameters produced optimum cooling efficiency of 81.05% with desirability of 98.3% from optimal cooling parameters of 2.33 L/min of water flow rate, 61.24 mm of pad thickness and 1.78 m/s of air velocity. The water flow rate and pad thickness had positive significant effects on the cooling efficiency while air velocity has insignificant effect. Cooling efficiency increase with both increased in water flow rate and pad thickness. The model showed that the value of coefficient of determination, R2 (88.86%) was high and p-value of 0.0010 at alpha = 0.05. Hence the model can be said to be of high significance and can adequately predict the cooling efficiency of solar-powered evaporative cooling system.