(R)Evolution of Refrigerants

Abstract

As we enter the "fourth generation" of refrigerants, we consider the evolution of refrigerant molecules, the everchanging constraints and regulations that have driven the need to consider new molecules, and the advancements in the tools and property models used to identify new molecules and design equipment using them. These separate aspects are intimately intertwined and have been in more-or-less continuous development since the earliest days of mechanical refrigeration, even if sometimes out-of-sight of the mainstream refrigeration industry. We highlight three separate, comprehensive searches for new refrigerantsin the 1920s, the 1980s, and the 2010sthat sometimes identified new molecules, but more often, validated alternatives already under consideration. A recurrent theme is that there is little that is truly new. Most of the "new" refrigerants, from R-12 in the 1930s to R-1234yf in the early 2000s, were reported in the chemical literature decades before they were considered as refrigerants. The search for new refrigerants continued through the 1990s even as the hydrofluorocarbons (HFCs) were becoming the dominant refrigerants in commercial use. This included a return to several long-known natural refrigerants. Finally, we review the evolution of the NIST REFPROP database for the calculation of refrigerant properties.

Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part II: Gas Separation Properties toward Fluorinated Greenhouse Gases

“…Currently, a new generation of F-gases has emerged owing to recent bans on the use of HFC refrigerants [3,4], namely, the hydrofluoroolefins (HFOs). Due to their zero-ozone depletion potential (ODP) and extremely low GWP-very similar to that of CO 2 -HFOs are starting to be used as environmentally friendly substitutes for HFC refrigerants either as pure compounds or in HFC/HFO mixtures with moderate GWP [5].…”

Assessment of Low Global Warming Potential Refrigerants for Drop-In Replacement by Connecting their Molecular Features to Their Performance

“… 20 , 24 − 30 Replacing the current commercially used third generation refrigerants with a low GWP alternative is not straightforward and might lead to retrofitting the existing system, resulting in a trade-off, often overlooked, between meeting environmental constraints and incurring additional costs or compromising system performance. 31 − 34 To blame for this is the lack of experimental data on the physicochemical properties of alternative refrigerants, essential for their accurate technical evaluation and projection on industrial scale. 35 This is expected as experimentally obtaining all relevant properties is quite taxing in temporal and monetary terms, given the number of different properties, varying operating conditions, and possible working fluids.…”

PROperties of FIre Suppressant SYstems “PROFISSY” A Spreadsheet Application for Fire-Suppressant Bottle-Filling Calculations

“…NIST now has a thermophysical properties database known as REFPROP [13] with state-of-the art models for equations of state for pure fluid properties [14,15] and Helmholtz-based models for mixtures including the standards for the properties of natural gas mixtures [16]. A historical summary of the evolution of fluids used for refrigeration and the REFPROP program can be found in the review article by McLinden and Huber [17]. The REFPROP program has been widely adopted as a standard in the refrigerants community and is available to the general public as Standard Reference Database 23 and can be obtained from a NIST website [18].…”