Dielectric properties of alternative refrigerants: a review

This paper reviews our research, from experimental measurements of the relative permittivity on new and alternative refrigerants, to theoretical interpretation of the data and density functional and density functional self-consistent reaction field calculations for a series of HFC molecules. Experimental measurements were obtained as a function of temperature and pressure for Class B refrigerants - HCFC-123, HCFC-142b, HCFC-141b and Class A refrigerants - HFC-32, HFC-134a, HFC-152a, HFC-143a, HFC-227ea, HFC-245fa, HFC-365mfc and some mixtures of them: HFC-125/143a/134a (R-404A), HFC-32/125/134a (R-407C), HFC-125/143a (R-507), HFC-32/125 (R-410A). Density functional and density functional self-consistent reaction field calculations were performed for CHF/sub 2/CF/sub 3/ (HFC-125), CH/sub 2/FCF/sub 3/ (HFC-134a), CH/sub 3/CF/sub 3/ (HFC-143a), CH/sub 2/F/sub 2/ (HFC-32), and CHF/sub 2/CH/sub 3/ (HFC-152a). A particular emphasis has been given to the calculation of dimerisation energies, rotational potentials, polarisabilities and dipole moments.