Enhancing the performance of plug-in refrigerated display cabinets using R290 refrigerant and grooved tube evaporator

Plug-in refrigerated display cabinets (RDCs) are widely used in supermarkets but consume a lot of energy. This study aims to increase the label class of RDCs by using a new generation microchannel condenser, a grooved evaporator, R449A, and R290 refrigerants as alternatives to R404A and implementing modifications to the system. The created systems were tested according to the ISO 23,953-2:2023 standard and characterized in detail for both eco-design and energy labeling criteria. The study showed that the heat exchange efficiency of the grooved tube evaporator was higher than that of the regular tube evaporator. However, a 30% higher pressure drop was measured for the grooved tube evaporator than for the smooth tube evaporator. Performance analysis of the developed refrigerators was performed from energy, economy, and environmental perspectives. The average coefficient of performance (COP) of the RDC was calculated as 2.4, and the second law efficiency of the RDC was determined to be 45.2%. When using the R290 + grooved evaporator combination, CO2 emissions were reduced by 22.74% per year as compared to the R404A + smooth evaporator. With an energy efficiency index (EEI) of 43.4, RDC’s energy class was upgraded from “E” to “D.” It was found that the compressor consumed 80.3% of the total energy consumption. The resistance, employed in condensation pans and accounting for 8.2% of the overall energy consumption, was discovered to be the second crucial factor affecting the energy class. The improvements and upgrades to RDC may strengthen the understanding of enhancing performance and serve as the foundation for future studies.