Design, construction and evaluation of an evaporative cooler for the storage of sweet potatoes in the north Ghana
Keywords:evaporative cooler, storage weight loss, wet bulb temperature, dry bulb temperature, moisture content, energy content
A 14.4 × 86.0 × 70.0 cm mud evaporative cooler was designed and constructed for the storage of sweet potato roots to evaluate its performance in storing orange fleshed sweet potato variety (Apomuden) roots. The investigation lasted for 14 weeks, from November 2014 to February, 2015. The dry bulb (Tdb) and wet bulb temperatures (Twb) for the ambient storage ranged between 27.600C to 26.900C and 22.500C to 20.100C respectively with their corresponding RH of 64.00%, 77.00% respectively, while Tdb and Twb within the cooler ranged between 25.940C to 24.860C and 21.940C to 20.610C with corresponding R.H of 89.00% to 92.00% respectively. The efficiency of the constructed evaporative cooler was 87.17%. From an initial weight of 2000 g, roots weight decreased to 1298.3 g during the storage period, while the weight loss within the cooler was from 2000 g to 1570.65 g over the same period. Also, the moisture content of the roots stored under ambient conditions declined from 68.9% to 48.35%. Roots stored in the evaporative cooler declined from 68.9% to 60.80%. As mc decreased from 68.9% to 48.35%, energy content increased from an initial of 501 to 858.677 kJ/100g under ambient storage while in the evaporative cooler, as mc declined, from 68.9% to 60.8%, energy content increased from an initial of 501.518 to 642.296 kJ/100g. The evaporative cooler maintained the quality of the sweet potato roots by fourteen weeks while those stored in the ambient storage lasted for eight weeks.