Because no one HFC refrigerant can be retrofitted efficiently into the entire range of R-22 equipment, a wide and sometimes changing variety of HFCs have entered the market. The NEWS contacted a number of refrigerant manufacturers asking them to discuss some of their most popular HFCs for R-22 retrofits.

My column in the Nov. 12 issue of The NEWS focused on HFCs, especially low GWP HFCs as retrofits for R-22 systems. This column will focus on what I used to call “beyond HFC” refrigerants, although these days, the term might be “other than HFC” refrigerants.

While natural refrigerants start to slowly — and cautiously — gain a foothold in North America, their impact is more forceful almost everywhere else. What do other countries have to say about this?

Two recent refrigerant developments focus on CO2 and HFOs. One relates to CO2 in refrigeration; the other is an announcement of an HFO in air conditioning.

Those of a certain age may remember the original editions of the young teen series such as The Hardy Boys and Nancy Drew. Since the early 1970s, the series still around have been updated and condensed. I mention that because in the original series more attention was paid to minor details that made for interesting reading.

Recently, there has been a lot of talk about natural refrigerants such as CO2 and hydrocarbons gaining a stronger foothold. Yet much of the talk is related to the possible phasedown of HFC production. And currently, while there may be some talk about a possible phasedown, no actual action seems to be taking place.

Improving heat exchanger performance is one part — a critical one — in enhancing the overall system performance in HVACR systems. What is one way to do it?

The expanding applications for ammonia in commercial refrigeration are being demonstrated in several recent projects involving heat pumps. What constitutes one possibility for efficient management of heat energy?

It has been an interesting — and complicated — year when it comes to refrigerants. The year began with cutbacks in HCFC production. We had expected there to be about 90 million pounds of virgin R-22 in 2012, down a bit from 2011. But the EPA proposed at the most 80 million pounds and at the least 55 million.

Two new reports that provide detailed studies of refrigerants have recently been released. The research is evaluating how newer refrigerants — ranging from HFC and HFO f-gases to natural refrigerants such as ammonia, CO2, and HCs — stack up against the current crop of popular refrigerants.