ABSTRACT
As the global economy and technology have improved dramatically since World War II, the demand for human comfort has resulted in an increased demand for household refrigerators and freezers. Energy usage has increased also by the increased use of energy-consuming products. This change of lifestyle generates the demand to provide additional refrigeration capacity with increased energy efficiency. The introduction of refrigerant mixtures was considered mainly due to the increased demand of the larger refrigeration capacity, the better control of two evaporator temperature levels and the potential of improved energy efficiency. Refrigerators with two temperature levels were considered good applications for refrigerant mixtures because of one main inherent thermodynamic irreversibility: in conventional refrigerators and freezers, the higher temperature food compartment is cooled by an evaporator operating on the freezer temperature level.
