Cooling in data centers remains a hot topic. But the industry is struggling to exploit or even put a value on heat. Through the integration of energy systems and data centers, we can unlock the value of the recovered heat – turning a cooling problem into a sustainable carbon neutral revenue stream.
This article is part of a series, covering some of the key ideas contained in the SDIA’s flagship report on the future of Digital Infrastructure: Utility of the Future – Where Digital and Energy Infrastructure combine. You can download the executive summary today and be notified when the report is released.
Data Centers are huge sources of Heat
Processing chips inside data centers convert all their electrical energy into heat. This heat must be cooled or extracted to maintain safe working conditions for both the equipment and staff. If that heat were to be extracted, it wouldn’t need to be cooled. This is a double win for the data center. If that heat could be sold, not only would the data center save on cooling energy, but it would make money off the sale of the heat. Now that’s an interesting proposition for any data center.
Heat is an opportunity, not a burden
I know what you’re saying. You’re saying there’s no guarantee that the heat will be extracted because many heat consumers can’t guarantee their demand, so the data center needs to provision for the worst case scenario of cooling 100% of the heat it creates. This destroys the business case, because who wants to pay for all that pipe and cooling technology if it ain’t used. It’s a fair point, if you consider data centers to be island systems – but what if they’re not?
Let’s consider the Energy system for a second. A traditional Combined Heat and Power station (CHP) burns coal or gas to deliver both electricity and heat. This approach has two major benefits to the energy system. 1) It increases the efficiency of the CHP from 40% to 80% and 2) the sector coupling (heat and electricity) gives the energy system a huge amount of flexibility, exactly what is required to integrate large amounts of variable renewable energy sources in our electricity system.
Applying the CHP principle to Data Centers
Applying this model to data centers, we arrive at a combined heat and compute (CHC) station. CHCs are a concept for an energy integrated data center, where data centers can be colocated with the local Combined Heat and Power (CHP) stations. In effect, we have a 21st century, digital-era form of sector coupling. The energy-in is guaranteed by multiple connections to the highly available power station, and the energy-out (heat) can be easily recycled into the heat grid. It doesn’t need a heat pump, as the heat can be boosted by the CHP, and there is little additional pipe required. The best part? Availability isn’t affected because you’re as critical to the local energy infrastructure as the CHP. That means a minimum guaranteed amount of demand (almost all power stations have a minimum amount of power and heat they must produce).
In summary we have secure, guaranteed energy-in, secure demand for energy-out, no interruption to your IT schedule, no increased risk of downtime, a secondary revenue stream, and protection by integration into the most critically protected infrastructure around today. What’s not to love?
Heat – is hot right now.
Here is a real-world example: Vattenfall is already trialling a CHC at their 100% biomass Jordbro power station in Sweden, with a 1MW Pilot. This is starting to happen now, as data centers realise that the grid is not more secure than high priority power stations, as the heat they’re producing is increasingly difficult to cool, and as sustainability begins to play a larger role in the operations of data centers.
(P.s. I do appreciate that gas fired CHP aren’t exactly CO2 neutral, but we need to start somewhere. Large scale Hydrogen and Biomass based CHP’s are a very real possibility across Europe).
Want to know about the business case behind Heat Recovery?
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Mohan is Head of Research & Policy at the Sustainable Digital Infrastructure Alliance. The SDIA’s mission is to ensure digital infrastructure has a net zero impact on our environment, and is accessible and affordable to the next generation of innovators. As Head of Research & Policy Mohan leads the working groups in their attempts to solve major technical barriers to a truly sustainable digital infrastructure. These working groups focus on integrating Heat Recycling, smarter Energy Consumption and improved Server Utilisation Rates. Mohan authored the report “The Utility of the Future – Where Digital and Energy Infrastructure Combine”.