ASHRAE Publishes New Method of Testing Standard on Refrigerant Miscibility
From eSociety, May 2019
ASHRAE has a new standard that determines lubricant and refrigerant miscibility.
ANSI/ASHRAE Standard 218-2018, Method of Test for Lubricant and Refrigerant Miscibility Determination, establishes a test procedure to determine the critical solution locus of miscible properties of a lubricant and refrigerant mixture.
The standard applies to pure-component refrigerant and lubricants and multicomponent refrigerant and lubricant mixtures.
Adequate miscibility between the lubricant and refrigerant is desired in most HVAC system designs to maintain performance. With lubricant being miscible within the refrigerant, viscosity is greatly reduced. This promotes circulation of the lubricant throughout the system and its return to the compressor and minimizes the lubricant film thickness coating the heat exchanger coils, which helps promote maximum heat transfer, according to the standard.