Design, Construction and Thermal Evaluation of a Battery Powered Portable-Sized Picnic Cooler under Different Loading Conditions

Abstract

This paper investigates the thermal behaviour of a portable refrigerating box (picnic cooler) subjected to no- load, half-load and full-load conditions at the evaporating space.  The portable sized vapor compression refrigerating box (picnic cooler) was designed for both indoor and outdoor use; therefore its size was such that it can fit the rear of an automobile. The device was designed to run on a 12 DCV battery-inverter system to ensure its availability for use during power outage.  R-134a was selected as the refrigerant because it is eco-friendly and safe to use. The assembly was run at empty load, half-load, and full-load for a period of two hours each.  The temperature values were obtained from five terminals each at the evaporator and the condenser, and their mean values were recorded. The thermometric readings were obtained with thermocouples at a time interval of 10 minutes for an overall period of 120 minutes. The thermal analysis of the picnic cooler showed reduction of evaporator temperature as the refrigerator load increased from no-load to full-load. The condenser temperature, on the other hands, increased with the refrigerating load.