Transient and steady state study of pure and mixed refrigerants in a residential heat pump. Final report, October 1994-October 1995

The report gives results of an experimental and theoretical investigation of the transient and steady state performance of a residential air-conditioning/heat pump (AC/HP) operating with different refrigerants. (NOTE: The project was motivated by environmental concerns related to the replacement of stratospheric ozone depleting refrigerants as required by international agreement and U.S. law. Hydrochlorofluorocarbon (HCFC)-22, and a medium pressure refrigerant, is scheduled to be phased out of production and must be replaced. Significant empirical data are available on HCFC-22, but relatively little data exist on the transient performance of any of the zeotropic mixtures being considerd as HCFC-22 replacements). The experimental work, conducted by testing an AC/HP in environmental chambers, documented refrigerant performance for steady state, cyclic, and seasonal performance, evaluated various equipment modifications, and measured changes in the concentrations of refrigerant mixtures as a function of time. A computer model was developed, capable of modeling the transient and steady state performance of an AC/HP. This model is the first capable of representing the significant transient and steady state physics of an AC/HP operating with pure and mixed refrigerants while utilizing minimal empirical data.