Liquid cooling technology has been steadily gaining traction in the data center industry due to its ability to efficiently dissipate heat generated by HPC’s (high-performance computing systems).
At the same time, we’ve seen an immense amount of white space resolutely cooled by air, with no plan of ever being cooled by anything else. According to an Uptime Institute survey, a majority of enterprise IT operators (85 percent) do not employ direct liquid cooling. Interestingly, the percentage of those who do use it (16 percent) is surpassed by the percentage (22 percent) of operators who have no intention of ever implementing it.
The pace of adoption will depend on various factors, such as the specific needs of data center operators, the availability of mature and cost-effective liquid cooling solutions, and overall industry trends.
While it is difficult to provide an exact timeline for when all data centers will adopt liquid cooling, it’s evident that the trend is moving in that direction.
Go With The Flow?
First, let’s consider HPC’s. Liquid cooling is standard practice and all the leading supercomputers use it. It’s one place where power densities are high enough to make liquid cooling the only sensible option. Similarly, hyperscalers are also prone to using it, when the situation demands.
Next, there are two relatively recent, small announcements which signal increased interest.
One is an investment in a liquid cooling company. GRC (formerly Green Revolution Cooling) got a $28 million round of funding led by a whopping $25 million from SK Lubricants of Korea. Some people clearly see a serious future for the concept. There’s a little more to this: SK Lubricants is a petrochemical company keen to gather some green credibility, and it sees GRC as a way to develop a new business line that has environmental credentials.
The other is a company named Inspur who opened up a liquid cooled rack it makes for Chinese cloud giant JD to more customers. It’s built in a factory, with a capacity of 100,000 liquid-cooled servers per year, and it will be sold pre-bundled into racks. So Inspur, too, thinks liquid cooling is heading for a bigger market.
Bigger picture
To combat global warming and achieve decarbonization, it is crucial for the world to cease burning fossil fuels. The most challenging sectors to decarbonize are transportation, which heavily relies on oil, and building heating, often powered by natural gas. These practices have been justified due to factors such as cost efficiency. For example, in the UK, gas is approximately six times cheaper than electricity for heating purposes. However, it is imperative to transition from gas to renewable electricity for home heating, and this transition must be economically viable.
Max Schulze from the Sustainable Digital Infrastructure Association emphasizes the shift in value resulting from this change, stating that: “Now, heat is a very valuable commodity, especially when made from electricity.” Data centers, in particular, consume significant amounts of electricity, leading to concerns in certain regions like Ireland. Data centers, being financially capable, have the ability to switch to renewable energy sources, which are essential for decarbonizing the power grid. In Denmark, the rapid growth of data center projects posed a threat to the country’s renewable energy targets, prompting a slower pace of development.
Consequently, there is a growing resistance to the construction of data centers. However, it is important to recognize that whenever electricity is utilized, heat is inevitably produced. Therefore, data centers could potentially provide a solution to this problem. Countries with temperate climates require heat for residential and commercial spaces, and this heat should be generated from renewable sources of electricity. By purchasing renewable power and utilizing it for their operations, data centers effectively generate heat from renewable energy. This heat can then be shared or sold to those in need.
Nevertheless, data centers currently generate heat in the wrong locations and of the wrong type. In the future, it may be advantageous for them to adopt liquid cooling methods to produce optimal heat.
Looking North
Data centers have an incredible potential to contribute to heat sharing initiatives by redirecting their hot air into district heating systems. While challenges may arise, in some Northern European countries, where more than 50% of district heat is fueled by renewables, innovative solutions are being implemented to maximize the utilization of this excess heat.
In Finland, Microsoft has taken a proactive approach by strategically locating its new region next to a Fortum energy plant, ensuring that its hot air can be effectively utilized. Similarly, Sweden’s Stockholm Data Parks initiative has created an inviting space for data centers by establishing a site already connected to district heating. These initiatives showcase how air-cooled data centers can actively minimize heat wastage, unless more groundbreaking strategies such as Qarnot’s approach, which involves breaking down data centers into pieces installed as “digital boilers” in homes, are pursued.
In Norway, data centers are mandated to “consider” the reclamation of waste heat, although this may sometimes involve producing reports to demonstrate the lack of economic viability. Nevertheless, numerous data centers are being constructed with external vents, denoting them as “heat reuse ready” and ensuring that the responsibility for heat reuse is shared. Across Europe, the Climate Neutral Data Center Pact is propelling data centers towards carbon neutrality. While the pact acknowledges the importance of heat reuse and promises to actively seek opportunities, the focus on economic viability may often reveal limitations.
These examples and initiatives highlight the industry’s commitment to exploring and implementing heat reuse strategies, creating a positive trajectory towards more sustainable and efficient data center operations throughout Europe.
Immersion Cooling Examples
- Microsoft’s Project Natick: This is an innovative experiment that involves deploying data centers underwater. One aspect of this project involves using liquid cooling to manage heat dissipation in the submerged data center. In this setup, servers are submerged in a specialized non-conductive liquid coolant, which absorbs heat generated by the components. The liquid coolant is circulated through heat exchangers, and the heat is transferred to the surrounding water. This approach eliminates the need for traditional air cooling methods and takes advantage of the natural cooling properties of the water.
- Google’s Immersion Cooling: Google has also been exploring liquid cooling technologies for their data centers. In one instance, Google adopted an immersion cooling solution developed by a company called Submer. This solution involves submerging entire servers in a non-conductive liquid coolant. The coolant directly comes into contact with the components, efficiently absorbing heat. By eliminating the need for air cooling, this immersion cooling method allows for higher density server deployments and reduces energy consumption. Google’s adoption of immersion cooling demonstrates the potential of liquid cooling to address the challenges of cooling high-performance computing systems in data centers.
- NVIDIA’s DGX A100 Systems: NVIDIA, a leading provider of graphics processing units (GPUs) and AI computing solutions, has integrated liquid cooling into its DGX A100 systems. These systems are designed for AI and high-performance computing workloads. NVIDIA utilizes a liquid cooling solution known as the “Direct Liquid Cooling” (DLC) technology. With DLC, coolant is directly brought into contact with the GPUs, effectively dissipating the heat generated by these powerful processors. Liquid cooling allows for more efficient cooling of the high-density GPUs, enabling optimal performance and reducing the reliance on traditional air cooling methods.
- Oak Ridge National Laboratory’s Summit Supercomputer: This is one of the world’s most powerful supercomputers and incorporates liquid cooling for effective heat management. Summit utilizes a hybrid cooling system that combines traditional air cooling with liquid cooling. The liquid cooling solution, developed by IBM, involves copper plates attached to the processors, which are in turn connected to a liquid coolant circulation system. This setup efficiently removes heat from the processors and prevents overheating. By implementing liquid cooling, Summit achieves optimal performance while maintaining energy efficiency and reducing cooling costs.
These examples highlight how liquid cooling is being leveraged in different ways to address the increasing heat challenges in data centers. From underwater deployments to server immersion to integration into specific hardware systems, liquid cooling offers unique advantages in terms of cooling efficiency, density, and energy savings.
Inevitability
At some point, these regulations and promises may have to start delivering – and at that point, the only way to share data center heat on a massive scale will be to improve its quality. It will take a lot of collaboration but at some point there will be a market for data center heat. Sooner rather than later, data centers will find it financially beneficial to embrace liquid cooling methods in order to generate superior heat. In fact, it might even become mandatory for them to do so.
The data center market doesn’t always follow logic, but there is a reasonable argument that the data center market will eventually have to go with the flow.
