AUTOMATED ELECTRONIC EVAPORATIVE COOLER FOR FRUITS AND VEGETABLES PRESERVATION

Horticultural products such as fruits and vegetables are highly perishable in nature; thus, maintaining the optimal air conditions inside the storage helps extending their shelf life. However, commercially available cool storages can give chilling injuries to the commodities which its quality, color, texture and freshness are often sacrifice. Hence, the proponents aimed to develop an automated electronic evaporative cooler in prolonging and preserving the freshness and quality of fruits and vegetables. The study was designed to evaluate the effectiveness of the electronic evaporative cooler for fruits and vegetables preservation through (a) percentage weight loss, (b) visual quality, (c) degree of shriveling, and (d) determining the expectancy life of the commodities. To evaluate the performance of cooler, (a) calibration of the system, (b) evaporative cooling efficiency, and (c) monitoring of air conditions in terms of temperature and relative humidity were first done to attain its end goal. The study focused on construction of an automated electronic evaporative cooler in which temperature and humidity were kept under control as associated by the standard temperature requirement of a specific fruit or vegetable. The system was inputted with required temperature of particular fruits and vegetables; then equipped with temperature and humidity sensors, water circulation system, DC fans which were all connected to a microcontroller that provided the appropriate action or output. From various tests conducted, for reliability, the cooler had evaporative cooling efficiency of 85.5263% during 12 p.m. to 6 p.m. of the day. The cooler also indicated a temperature drop range of 1.40 to 3.40 ˚C and a relative humidity rise range of 9.30 to 20.30%. Moreover, the study also revealed that commodities placed inside the cooler had average percentage weight loss of about 2.50% to 5.50% while those exposed in ambient environment with about 4.50% to 10.30%. Through evaluation done by five vendors, the commodities inside the cooler were considered as field fresh without defects while those in ambient environment were mostly evaluated as with serious defects and had reached the limit of usability in terms of visual quality. Meanwhile, in terms of degree of shriveling, most of commodities inside the cooler showed no signs of shriveling, wilting or dryness compared to those in ambient environment which most were considered with evident but not serious shriveling. More so, using regression method, the proponents projected a trend line to determine expectancy life of the commodities and it was found out that tomatoes and bananas in ambient environment can reduce a five-percent weight after 78 and 42 hours respectively compared to commodities placed inside the cooler. Therefore, the proponents concluded that commodities stored inside the cooler showed better conditions in terms of percentage weight loss, visual quality and degree of shriveling compared to those exposed outside the cooler. Furthermore, the study proved that the use of electronic evaporative cooler can prolong the shelf life of the commodities