Describes measurements of concentration shifts caused by internal fractionation performed using a wide glide nonazeotropic mixture in a vapour compression cycle. The phenomenon was modelled an applied to other alternative refrigerant mixtures such as R407C, R404A and R410A to predict their concentration shift and the associated performance changes. Describes oil solubility measurements with regard to the composition shift by fractional oil solubility. Notes research using these results as a basis to calculate on a generalised basis the behaviour of nonazeotropic mixtures in vapour compression cycles of different configurations with regard to the concentration shift caused by the separation internally in the system, by fractional oil solubility and by leakage.

KEYWORDS: year 1997, Refrigerants, mixtures, non azeotropic