Investigation on the energy and exergy efficiencies of a domestic refrigerator retrofitted with water-cooled condensers of shell-and-coil and brazed-plate heat exchangers

Domestic refrigerator is one of the major energy-consuming appliances, and the enhancement of its energy efficiency plays a vital role in implementing the energy conservation policies and green building concepts in residential sector. The major strategies used to improve the performance of domestic refrigerators are the replacement of existing components, use of alternative refrigerants and the reduction in condensing pressure. Therefore, in this work, the conventional air-cooled condenser has been replaced with water-cooled condensers such as shell-and-coil and brazed-plate heat exchangers to maintain a low compression ratio and condensing pressure. The performance of a domestic refrigeration system retrofitted with water-cooled condensers has been studied using experimental methods. The result showed that the system with water-cooled condensers reduces the pull-down time and the per day energy consumption by 70% and 3.5%, respectively. Moreover, the proposed system can improve the COP and exergy efficiency by 6.4% and 4.9%, respectively. Compared to shell-and-coil heat exchanger, the system with brazed-plate heat exchanger can reduce irreversibility and TEWI by 3.9% and 3.7%, respectively. In this study, the system with brazed-plate heat exchanger showed better performance than the shell-and-coil heat exchanger for all operating conditions.