Assessment of evaporative cooling system potential for short-term storage management of vegetables during transportation

Abstract

A system based on direct evaporative cooling principle for short-term storage management of vegetables during transportation was designed, developed and assessed its performance. The evaporative cooling applies the principle of water evaporation to achieve temperature reduction and relative humidity increment. The system comprises evaporative cooler, power supply (battery, battery charger and power inverter), control panel, storage unit and real-time data monitoring (of temperature, T and relative humidity, RH). The evaporative cooler consists water reservoir, pump, cooling pad, extraction fan, connecting pipe and control panel. The system (that applies alternating current (AC)) can be powered by two-12 V serial truck batteries (direct current, DC) via power inverter. In this research, the effect of water type towards cooling process inside storage unit was studied too. The use of icy water as an evaporation media exhibited higher temperature reduction, T (6.11 ± 2.30 C) as compared to ambient water (4.06 ± 1.91 C). RH for both cases achieved 99 %. The quality of selected leafy vegetables (green amaranth, water spinach and choysum) for fresh market that underwent evaporative cooling storage treatment (T1) was assessed. Post four-hour storage, leafy vegetables stored under T1 exhibited the least weight loss as compared to ambient storage treatment (T2) and cold storage treatment (T3). However, post two-week storage, the vegetables quality that underwent T1 was comparable to T2, but slightly lower than T3. The system exhibited potential to maintain vegetables quality during the short-term storage in transportation.