Experimental development of alternative mixtures to isobutane. Energy optimization.

Isobutane is one of the most widely used refrigerants in stand-alone applications, since it presents good energy performance and its GWP is close to 3. However, recent research shows that it is possible to use refrigerant blends with similar thermodynamic characteristics and can provide better energy performance than isobutane in terms of energy consumption. This work presents the experimental optimization of the mass composition of different alternatives blends to isobutane. Mixtures are based on butane and a second refrigerant, always with a GWP bellow 150. For each mixture, the composition of both refrigerants was varied until an "optimum" composition was reached, based on COP and cooling capacity parameters. The optimization was performed in a vapor compression experimental bench, which allows to measure experimentally different thermodynamic parameters that occur in the heat exchangers.