Performance of Chlorine-Free Binary Zeotropic Refrigerant Mixtures in a Heat Pump

摘要

The phase-out of the currently used refrigerants during the next decade requiresfast and accurate methods to evaluate possible alternatives for the existing refrigerants. The report investigates possible replacement refrigerants for R22, where the replacements are binary zeotropic mixtures of the following hydrofluorocarbons (HFCs): R23, R32, R125, R134a, and R152a. The method, that was chosen, is based on three steps: (1) determining possible mixture components, (2) evaluating all fifteen possible mixtures using a simulation program developed by NIST and determining the best performing mixtures, (3) evaluating the best performing mixtures in a NIST build test facility. Following the path, two refrigerant mixtures, R32/R134a and R32/R152a were found to perform better than R22 with respect to COP and volumetric capacity for certain composition ranges. The used simulation model proved to be a very precise tool in finding possible replacement fluids and their possible performance advantages. The results give the confidence that this time saving combination of simulation and testing is a very powerful engineering tool.