Presents a comparative study of fluid flow heat transfer characteristics of new alternatives R410a, R410b and R507 and the mixture R32/R125/R143a/R134a. States the data on heat transfer characteristics were obtained inside enhanced-surface tubing using an experimental setup composed of a heat pump with 8kW capacity under steady state conditions. States the results show that R507 has the lowest heat transfer rate compared to the refrigerant blends and R-22. R507 exhibited a higher pressure drop than the refrigerant mixtures, including R-22.

KEYWORDS: year 1997, Refrigerants, comparing, mixtures, R22, R410a, R410b, R507, heat pumps, heat flow, heat transfer fluids