The data center industry is poised for significant change in the refrigerants which are used in cooling systems, changes that you’d do well to pay attention to in order to understand the implications for your own data center.
We’ve known for years, even decades, that refrigerants used in all sorts of cooling systems – from cars to home window units and refrigerators – are harmful to the earth’s ozone layer and impact on the global warming. So we’ve been phasing out the harmful ones over time while constantly looking for effective, safe replacements – typically with no shortage of prodding from various governmental bodies.
Worldwide Refrigerant Regulations
First waves, around 2002 in Europe and more recently in North America and Asia, were to ban any blend which contributes to the ozone depletion, while recent and next standards are going to reduce the impact on the general increase of temperature generated by refrigerant leakages in the atmosphere. More recently, an accord to cut the worldwide use of a powerful planet-warming chemical used in air-conditioners was signed recently.
Data centers are no exception to this regulatory trend and, while the issues are quite clear, the solutions are far less so.
The two main refrigerants used in data center cooling systems today are R410A, used in small to medium-sized data centers that require about up to 300-400kW of cooling capacity per unit, and R134a, used in larger systems. The problem with both of them is they have a relatively high rating in terms of global warming potential (GWP), a measurement of environmental impact. While there are potential replacements for both of them that have lower GWPs, they are not without issues of their own.
The most environmentally sound option would be to use “natural” refrigerants, meaning substances that occur naturally as opposed to man-made chemical compounds. The most common options are ammonia, propane and CO2, each of which have low GWP ratings (in fact, CO2 is the baseline by which GWP is measured).
But they each also have issues. Propane and ammonia are highly flammable and ammonia is also toxic, while CO2 is simply not very efficient for cooling applications and requires a pretty complicated, and expensive, technology. As a result, only a niche market exists for each option.
Which brings us to the man-made refrigerants. Some of them are emerging as potential replacements for R410A, L-41, R32, DR55 and DR5.