Refrigerant, Household Appliances, Energy Efficiency
During the last decades, the energy consumption of household appliances was reduced continuously. The reason for this developments is caused by higher power costs and stricter statutory rules. To achieve these goals, it was necessary to improve and evolve each component of the cooling circuit as well as the insulation. For instance: On the compressors side: Introduction of variable speed compressors In the heat exchangers: Improvement of heat transfer (e.g. using fans, new geometry etc.) Expansion device: Further development of the inner heat exchanger between capillary tube and suction line Insulation of the cabinet: Improvement of the gaskets and introduction of vacuum insulation panels This development led to a change in the boundary condition of the cooling circuit of domestic refrigerators and freezers. During normal use the evaporation temperature increased while at the same time the condensing temperature decreased. In addition, the demand for cooling capacity is lower than in the past, due to improved insulation of the appliance. It is worth to evaluate if R600a (isobutane) is still the best refrigerant to achieve the best result in energy efficiency. A theoretical analysis of more than 100 refrigerants has been carried out. The most promising refrigerants are tested inside different domestic appliances. Apart from the main scope of reducing the energy consumption the impact on the environment (ODP / GWP / toxicity) and also the costs are taken into consideration. As a result, it is possible to reduce the energy consumption in accordance with IEC62552-2015 up to 5% by using an alternative refrigerant. The impact on the environment of the alternative refrigerant is comparable to isobutane.