INTELLIGENT GREEN TECHNOLOGY
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 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.
All of these are still under development and are, again, not without issues. Chief among them is they are all flammable, although slightly, while current solutions are not flammable. But clearly it is preferred that the refrigerant coursing through your datacentre not be so flammable that it presents a fire hazard.
It may be some time before we see a suitable replacement for R410A on datacentre applications.
The news is brighter on the replacement for R134a. Here we have got three main refrigerants coming to the fore: R1234yf, R1234ze and some blends of R1234ze and R134a, one of those is defined XP10. Of those, R1234yf is going to be used massively in the automotive industry and is consequently expensive and not widely available, while any blends between R1234yf and R134a are featured by not a really low global warming potential.
Overall, R1234ze seems to have the most support. It is only slightly flammable and fairly efficient, although not quite as strong in terms of cooling capacity as R134a. Given
GWP
Global warming potential is an index based on CO2 equivalent tons to measure the impact of a greenhouse gas on the atmosphere. Refrigerants commonly used on chillers have global warming potential values between 1,000 and 4,000. New alternative refrigerants dramatically decrease such values. that, it works out to be about 30 % more expensive than R134a. Still, of the three, R1234ze is fairly far along in terms of development and appears to offer the best tradeoff in terms of price, performance, flammability and global warming potential.
Moving to a new component, such as one as critical as refrigerant, is certainly a challenge, however the good news is that it is possible to leverage R1234ze specific features in order to not just greenwash cooling, but also get the opportunity to improve machineries.
Another important opportunity which is offered by this new refrigerant is the application in warm areas of high water temperatures. A current limitation of high water temperature application is the maximim ambient conditions allowed by R410A or R134a when chillers are providing 18, 20 ° C chilled water.
So, expect to see changes in how we cool our datacentres coming down the pike. It is clear that some changes will come sooner than others, but that change is coming.
Maurizio Frizziero is the current Global Product Line Manager for Air Economisers and Chillers at Schneider Electric
46 Issue 04 INTELLIGENT TECH CHANNELS