In one corner we have all the so-called natural refrigerant folks. They are the ones proposing CO2, HCs, and ammonia as options for the types of equipment that has long been using HFCs. This is not to say that such alternatives are pure drop ins. There are equipment redesigns, some significant. But currently CO2 is being used more and more in commercial refrigeration such as in supermarkets; HCs are starting to be used in smaller refrigeration units; and ammonia is being planned for use in North American supermarkets.

My feeling is that as technology improves and if regulations change in municipalities, more and more CO2, HCs, and commercial ammonia projects will come on line.

Another option beyond HFCs are HFOs. Like HFCs, they are synthetically produced. But unlike HFCs, they have a lower global warming potential (GWP) which is looked favorably upon by many environmentalists.

What I just noted is a prime reason HFO-1234yf is being introduced in automobile air conditioning. Its GWP is on the low end and well below the European threshold introduced a few years ago that is causing HFC-134a to face phaseout in European automotive.

There is still quite a bit of research going on in terms of stationary applications. And the more research that is being done, the more advocates see a reality in familiar stationary equipment.

To make things even more interesting, the recent Purdue University conferences related to HVACR had a number of papers on HFC-32 as a stand-alone refrigerant. Its most familiar use now is as a blend in HFC-R-410A. But as a stand-alone it is a low GWP (675 vs. 2088 for 410A).

There are three things to consider here.

• First, should HFCs come in for a phase down, might those advocating the phase down agree to keep around lower GWP HFCs longer than high GWP HFCs? In other words, draw an ‘acceptable’ GWP line in the sand. In effect this is what happened in auto a/c in Europe.

• A second consideration is the Life Cycle Climate Performance (LCCP) that is kind of a variation on the old Total Equivalent Warming Impact. In the most simplified explanation, this is a way to measure the overall effect a refrigerant or a system has on the environment. In other words, if a refrigerant has a really low GWP, but it is put into a system that has to pull more energy, which in most places comes from the electric grid, which comes from burning coal, which itself is a polluter, they may end up being a worse solution than a higher GWP refrigerant. Advocates of R-32 contend it has a really low LCCP. Researchers and manufacturers focus on LCCP and hope that regulators will do the same.

• The third part is the flammability issue. For example, HFOs and R-32 have an A2L safety rating meaning slightly flammable while HCs are A3, higher flammability. Supporters of HFCs raise caution over working with highly flammable refrigerants. Advocates say it's done all the time in Europe and Asia.

In talking with North American contractors, a recurring theme is that whatever regulations and building codes will allow to be used – HFCs, HFOs, HCs, CO2, ammonia, whatever – contractors will work with those refrigerants, provided the manufacturers produce the equipment designed for the alternatives and the manufacturers stand behind the products.

Publication date: 9/3/2012