The Raid on Refrigerants
By Barbara Horwitz-Bennett
Editor’s Note: The following observations on refrigerants come from the participants in CSE’s 12/04 M/E Roundtable, which discusses hybrid chiller plants. Look for it soon, along with the rest of our December issue, at www.csemag.com .
When it comes to choosing a refrigerant for chillers, what factors go into play?
“Of the two primary new refrigerants, R123 and R134a, one is slightly better for reducing ozone depletion and the other is slightly better for reducing global warming. But in reality, we are splitting hairs. Both refrigerants are significantly better for the environment at a slight penalty to efficiency,” explains Ken Clark, P.E., principal and project manager, Burns & McDonnell Engineering, Kansas City, Mo.
More specifically, the low-pressure refrigerant R123 offers slightly higher efficiencies, but has an ozone depletion factor, while R134A is a high-pressure refrigerant with a high global warming factor, according to Pete Zak, P.E., principal, M/E/P group manager, Graef, Anhalt, Schloemer & Associates, Inc., Milwaukee. However, Zak adds that with R134A, “we have found this to require larger machines, which may or may not be competitive with low-pressure machines.”
Zak also mentions refrigerant blends as an alternative choice. “Refrigerant blends use a combination of environmentally acceptable refrigerants and present a high efficiency. They work well, but owners are hesitant to buy into something less familiar,” he explains.
According to Milton Meckler, P.E., CPC, president, Design Build Systems, Los Angeles, approaching things from a life cycle standpoint is best.
“Assuming that there is an established given ratio of hybrid gas to electric capacity, a longer term, i.e., 15-20 year view, when trading off performance efficiency vs. environmental impact is preferred,” says Meckler.
However, Meckler also posits that personal choice on the part of building owners may eventually give way to regional regulations arising from continuing global warming concerns.
At the same time, Clark bemoans the phasing out of R22. “The real tragedy is that R22 will be lost as a refrigerant in the future. This is an efficient refrigerant that has served the air-conditioning and refrigeration industry well for decades,” he laments. “But now the industry has to change at significant expense to the economy because it is slightly less desirable for the environment over the new refrigerants.”