A Portable Solar-Assisted Evaporative Cooling Chamber (ECC) Designed to Prolong the Freshness of Fruits and Vegetables

Abstract

A portable solar-assisted evaporative cool chamber (ECC) was developed to extend the shelf life of fruits and vegetables for small-scale farmers and vendors as an alternative to conventional cold storage methods. The chamber had a storage capacity of 250 kg and occupied a space of 0.84 m³. Solar panels (200 W) powered a suction fan (7.4 W) and a water pump (9 W). A battery (150 Ah) and a charge controller were utilized to store excess energy and ensure the continuous operation of the system. Within the ECC, a remarkable decrease in temperature and an increase in relative humidity (RH) were observed. The temperature dropped by 9.3 to 15.4ºC, while the relative humidity rose from 46.7 to 64.3% compared to the surrounding ambient conditions. The ECC demonstrated an exceptional saturation efficiency of 98.48%. For duration of 15 days, a variety of selected fruits and vegetables were stored both inside the ECC and under ambient conditions. The ECC storage extended the shelf lives of different produce: tomatoes lasted 12 days (compared to 6 days ambient), okra for 10 days (compared to 6 days ambient), cucumber for 11 days (compared to 5 days ambient), bananas for 11 days (compared to 5 days ambient), apples for 41 days (compared to 18 days ambient), and papayas for 17 days (compared to 8 days ambient).