Sustainability is the new buzz word in the industry. Corporations and hyper-scalers are demanding sustainable data centers because their customers demand a reduction in the carbon footprint of power-hungry data centers. Consequently, there has been a surge in demand for data centers in the Nordics where power is genuinely ’green’ sourced from hydro and wind turbines, not the renewable energy certificates data centers in other regions rely on.

Having worked in the Nordic region for over 10 years, I have watched this change from indifference for the carbon footprint and its associated power and cooling load to its current place high up the corporate agenda. The reasons in Europe are the fear of legislation from the European Union, the need to report carbon footprint in company accounts, and customer demand. The carbon footprint of data centers was first highlighted for the general public in the excellent Greenpeace report, Click Clean and Dirty Data. This is where we are, so how is it that immersion cooling benefits sustainability?

Put simply, it helps in two ways. By reducing the power demand of the data center and reusing the waste heat from the servers for other applications, immersion cooling has a huge impact.

Let’s begin with the power demand of the data center from the grid and its stand-by generators. This comprises IT load and mechanical load for the cooling/ventilation. Great strides have been made in reducing the cooling/mechanical load in the last few years. In the Nordics, the lower average ambient temperatures help provide ‘free cooling’ for much of the year. Fjords and lakes are sometimes used as a cooling source, but this is not possible in much of Europe and the rest of the world where ambient temperatures are much higher.

So how does immersion cooling help in this regard? The answer is quite simple. The internal fans are removed from the servers since they are not required in an immersion cooling solution. (They would act like little propellors.) Removing the fans reduces the IT energy load by 10-15%, a very significant figure. Essentially, 1000kW of compute can be performed with only 900kW of power — the immersion cooling system would only require a miniscule fraction of this 100kW savings to operate. This has huge implications on every aspect of the data center infrastructure. There is no additional cooling load, which normally ranges from 150kW to 600kW depending on the design and location. The electrical infrastructure is substantially reduced in terms of switchgear and cabling. The stand-by generators are also smaller due to the reduced load, so apart from the reduced power demand to the site there is also a reduced CapEx and OpEx.

The next aspect is the re-use of the server heat. This has become a huge issue in Europe with many cities, including Frankfurt, Amsterdam, and Dublin demanding strategies for server heat re-use as part of the planning/permitting process. So how does immersion differ from air cooling in this regard?

Because it circulates around all of the components, the cooling fluid captures 100% of the server heat, as opposed to 30% in air-cooled solutions. Better still, the temperature of the coolant is around 45C, far more usable than the 20-30C of an air-cooled system. Depending on the site location, the waste server heat can be used in district heating, fish farming, or manufacturing processes like wood pellet manufacture as EcoDataCenter does in Sweden.

There is another aspect which wasn’t considered until recently. The carbon footprint of the construction of the data center itself and its disposal at ‘end of life’. This is now being considered in the calculations of the impact of the data center on the environment. Everything from the building components to the equipment installed, and then the disposal of that equipment at ‘end of life’. This is known as Scope 1, Scope2, and Scope 3. There is a range of equipment that is either not required or is reduced in size using immersion cooling. Consequently, the overall carbon footprint is less. In addition, the building is smaller so it requires fewer construction materials.

In conclusion, it is safe to say the immersion cooling benefits sustainability by significantly reducing the carbon footprint of the data center, probably between 15-30% depending on location and ability to re-use the waste heat. The way forward for a sustainable future then!

Total Data Centre Solutions is a GRC agent in Europe & the Nordics.