Design and Development of Non-Refrigerated Storage System for Selected Fruits and Vegetables
Lorena N. Miranda1, Alvin P. Guadalupe1, Kevin F. YaptenCo2,
Emmanuel Q. Amatorio3, Gloria D. Masilungan3
and Ruben E. Manalabe1
Mechanical refrigeration is the most effective method in maintaining the quality of fruits and vegetables. However, due to high installation and operating costs involved, the adoption of refrigeration is still limited especially for small farmers, traders and retailers.
A simple and inexpensive cooling technology was developed. The cooler uses the principle of evaporative cooling with the 20-cm thick charcoal as cooling pad. Two prototype designs were fabricated and tested, namely, display-type and cabinet-type evaporative cooler. The prototype evaporative cooler can reduce the ambient temperature by 2.1 to 6.3°C and raise the relative humidity by 12.4 to 36.5 %. The humidification efficiency of the display-type cooler ranged from 74.3% to 81.5% and 93.5 to 99.3 % for the cabinet-type. The display-type had an average water consumption of 1.1 L/hr whereas the cabinet-type had an average consumption of 1.8 L/hr.
Commodities placed in the evaporative cooler have better visual and textural quality than those samples left in the ambient due to reduced moisture loss. Evaporative cooler can increase the shelf-life of selected fruits and vegetables by one to four days. Commodities tested were eggplant, tomato, bitter gourd, pechay, cabbage, Chinese cabbage, sweet pea, green pepper, cucumber, Baguio beans, string beans, and calamansi.
Keywords: evaporative cooler, ambient, moisture loss, quality, shelf-life, temperature, relative humidity, vapor pressure deficit
1 Postharvest Engineering Department, Bureau of Postharvest Research and Extension, CLSU Compound, 3120 Muñoz Science City, Nueva Ecija, Philippines; 2Assistant Professor, Agricultural and BioProcess Division (ABPROD), Institute of Agricultural Engineering (IAE), College of Engineering and Agro Industrial Technology (CEAT), University of the Philippines Los Baños, 4031 College, Laguna, Philippines. 3Postharvest Horticulture Training and Research Center, College of Agriculture, UPLB.