Modeling and Design of a Solar-Powered Refrigerator for Vaccines Transportation in Remote Regions

Abstract

In this paper, a portable photovoltaic (PV)-powered vaccine carrier intended for “hard to reach” areas that suffer luck of electricity and transportation has been proposed. The design of the proposed system has been analyzed and each of its elements (PV panel, battery, converter, and refrigerator) has been deeply studied, modeled, and validated through simulation as well as experimentally. These elements are carefully selected to form a robust, light system and at a reasonable cost. To maximize energy production, the PV panel control using a maximum power point tracking (MPPT) controller has been examined. Moreover, to ensure an appropriate battery charging and thereby prolonging battery life, state of charge (SOC) estimation using the Luenberger observer has been studied. The proposed system has been investigated under different climatic conditions. It was subjected to different daily profiles of irradiance and temperature measured in three seasons, namely, winter, spring, and summer in Marrakesh, Morocco. As expected, for all studied cases, the proposed PV-powered vaccine carrier works adequately and maintains continuously a low temperature of 4 °C (as required by the World Health Organization (WHO) for vaccine preservation) for a journey of 15 h. These results making it a very suitable option to transport vaccines safely in remote areas.