Measurement of Solubility, Viscosity and Density of R-410A Refrigerant/Lubricant Mixtures
ASHRAE RP-928 (Abstract)
by Richard C. Cavestri, Ph.D. and William R. Schafer, B.A.
Measurements of the refrigerant vapor/liquid lubricant equilibrium viscosity reduction of four polyolester lubricants, viscosity grades 32 and 68 ISO VG, with the refrigerant R410A were taken between -13°F (-25°C) and 257°F (125°C) and up to 700 psia (4824 kPa). A high and low miscibility grade polyolester was analyzed for each viscosity. The viscosity, density and composition of the solubilized gas mixture in solution with the lubricant were obtained with constant gas vapor composition in the viscometer head space. This refrigerant has a very small temperature glide, but is considered a zeotropic blend nonetheless.
The fractionation data presented was obtained from individual isothermal measurements. The isotherm for each temperature detailed the composition of the equilibrium gas fractionation of R-32 and R-125 in the lubricant, mixed vapor pressure, concentration of the total mixed blend (percent by weight) in the lubricant and viscosity in centipoise (cP) and centistokes (cSt).