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Warming up to liquid cooling

Chris Wellfair, projects director at Secure I.T. Environments, outlines how the phasing out of R407a gas, with future supply and rising cost issues, may mean it is the right time to switch to a liquid cooling system, rather than continuing with the replacement R410a gas.

As any data centre manager knows, more and more is being expected of their installations. Whether it is supporting voice over IP communications, CCTV, providing remote working access for staff, or just the huge amount of storage capacity that companies need to support the never-ending ability of users and applications to consume it. Once you start adding in all the essentials, such as redundancy, mirroring, back-up, UPS, fire protection and environmental controls, things are getting pretty packed in there.

Expect even more to be crammed into the data centre over the coming years, not just in the areas outlined above, but new areas such as the Internet of Things. A UK survey we conducted earlier this year amongst IT professionals found that companies are looking to invest in new technologies to support their businesses across 2020 and 2021. Improving data centre connectivity to benefit cloud services and high-performance computing were joint top at 27%, followed by incorporating 5G technology and artificial intelligence at 24%. Achieving better performance and crunching data are seen as key to competitive advantage and, as we all know, that means more processing power.

Deciding how best to accommodate these needs can throw up some questions depending on the level of utilisation in your data centre. Of course, taking the decision to invest in a whole new data centre can be prohibitive on a number of grounds, including real estate and cost, so many organisations are looking to increase the density of servers within existing spaces. Depending on how well stocked your racks are already, this can create problems.

One of the biggest challenges with this approach is cooling, but changes in regulations around gases may create an opportunity for organisations to consider changing their approach to cooling, which will not only ensure they are conforming to European Union (EU) regulations, but make their contribution to reducing the impact of climate change, and achieve more densely packed racks whilst keeping everything within optimal environmental specs.

Changes in the F-Gas market

We are all very aware of the changes taking place in the refrigerant market as the industry seeks to make its contribution to reducing the use of fluorinated greenhouse gases (F-Gases). The EU quota system is being enforced by the UK Environment Agency, and means that only companies with an EU quota can supply the gases.

R22 refrigerant has been in the process of being phased out for a long time and, as of January 1 2020, became illegal to both manufacture and import. Many had already switched to R407c before this date and it too has now been replaced by R410a, a high pressure gas, so less of it is required in systems. With each of these steps the preceding gas increases in price and becomes harder to find.

R410a has been used for many years, and though its production is being reduced, it is still in many larger systems today as they are not ready for the next gas, R32, as the compressor technology is not quite available for those systems. It is however, already making its way into smaller systems such as UPS room wall units.

Ultimately, between the years of 2015 and 2030, the CO2 equivalent of the HFC refrigerants in use will have been cut by 80% and this will be a fantastic achievement in terms of the environmental impact of cooling. The challenge is that the current reduction in R410a does not have a replacement for all applications. This has led to some manufacturers working to find other ways to reduce the amount of gas they use. For example, creating office systems that continue to use gas, but also water in fan coils, where gas would have been used in the past.

The liquid cooling option

The need to get more from our data centres, and the regulatory changes that are taking place, leave companies wanting to upgrade their cooling systems with an interesting choice. Do you continue doing everything needed to maintain the gas-based cooling systems that you already have, or do you plan for a transition that will help increase the density of your data centre, and meet future demands.

Liquid cooling does not need to revolve around some ‘secret sauce’ ingredient. Water is 3,400 times more efficient than air at removing heat, and rack level extraction can be very straightforward. Another benefit of liquid cooling is that it can be implemented as you expand the data centre, there is no need to wholesale remove existing gas-based systems, which would be a huge CAPEX expense.

There are two principle methods of cooling; the first is direct-to-chip cooling which is often used with CPU and GPU units. As the name suggests, it draws heat directly away from its most intense source and is very efficient. It allows servers to be much more densely packed as the heat is drawn away in the liquid before it escapes into the air, building up and impacting surrounding components.

The second method is immersion cooling, which can be used with a range of devices such as solid-state drives, and involves placing devices in a liquid dielectric bath. That may sound like madness, but dielectrics are used as insulators in a range of high-voltage applications including sub-station switchgear and transformers. Working with immersion cooling requires a very different approach when it comes to maintenance, and some devices are not suitable without reconfiguration, but again it is nothing that cannot be overcome.

The cool reality

Undeniably, cooling technology is moving in a direction that will create huge opportunities for improved data centre density, and a much greener industry and wider world. Liquid cooling will become commonplace in the data centre. The choice for data centre operators is to start planning their transition away from F-Gas. It might take 10 years, but, as we all know, data centres are long-term investments and that 10, will soon become five.

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