Characteristics of blends using low GWP molecules for application in centrifugal and screw compressor-based chillers.

Abstract

This paper summarizes information on blends utilizing low GWP olefin-based refrigerants targeted to application in centrifugal and screw compressor-based water chillers. These types of chillers tend to use shell-and-tube heat exchangers that permit fractionation to occur when running with zeotropic blends. Fortunately, several azeotropic mixtures have become available, such as R513A, R514A, R515A/B, and R516A. This paper provides a review of the thermodynamic interactions when blending various low GWP refrigerants and azeotropic mixtures suitable for use in vapor compression (e.g., HVAC&R) or expansion (e.g. ORC) applications. This includes molecules already in commercial use and those that have recently come to light. A summary is provided of thermodynamic properties, thermodynamic cycle performance, heat transfer charac-teristics, flammability, stability, and toxicological properties.