Collin Arocho
12 January 2021

In the world of power-hungry data centers, companies big and small are coming together as part of the Open Compute Project (OCP) to build consensus and paint the industry green. In collaboration, OCP platinum members Shell and Asperitas believe they have a sustainable solution to keep your IT cool: immersing it in a specialized cooling fluid to drastically reduce energy consumption, while simultaneously harnessing waste heat energy for reuse.

Ready or not, the energy transition is coming. But maybe not the way you expect. This part of the transition isn’t coming from government regulations to try to cap emissions. Rather, it’s stemming from industry leaders and technological innovators putting their heads together to lessen our carbon footprint and mitigate our collective impact. For the last two years, Shell and the Netherlands-based Asperitas have been doing just that.

The duo has set its crosshairs on energy-guzzling data centers that are devouring huge amounts of power and contributing largely to emissions of CO2. The solution: immersion-based cooling of IT. In other words, sinking electronics and IT into baths of a specially formulated dielectric liquid that can effectively, and very efficiently, cool the components.


A couple of years ago, while Asperitas was still in its R&D phase, the data-center cooling specialist recognized its potential to have drastic effect on the industry. It was at this time, in 2018, that the Amsterdam-based startup reached out to start first collaborations with Shell, and in the same year looked to take a leading role in shaping the immersion cooling industry by joining the ranks of the Open Compute Project (OCP), a community-based foundation aimed at elevating the IT industry by sharing IP, ideas and best practices. The idea being that through shared experiences and collaboration, the group could establish new hardware designs that are optimized and tailored to specific needs, offering end-users high efficiency and scalability. Almost two years ago, OCP launched the Advanced Cooling Solutions (ACS) initiative within the Rack & Power work group, where Rolf Brink, founder and CEO of Asperitas, became the project leader for the immersion-cooling pillar.

Asperitas module inside

According to Brink, there wasn’t much consensus within immersion cooling, as there was no common frame of reference, and requirements within the realm were nonexistent. In his role at ACS, however, he got the opportunity to work with a community of global industry leaders that together discussed and formulated projects to help the industry move forward. “Up to this point, the dunk-and-pray strategy was the most common practice in the domain. People would go buy an off-the-shelf server, make some small modifications through the thermal interface material on the CPU and then dunk it in the liquid and hope it kept working,” laughs Brink. “But eventually, through collaborative efforts, we were able to publish a white paper on the minimum requirements for immersion cooling. For the first time, we had established a basic frame of reference for the domain, and we had a good starting point.”


Soon after, the ACS group kicked off a new project focused on liquid compatibility. “There are two main families of liquids that can be optimized for the immersion cooling sector: hydrocarbons and fluorocarbons. OEMs and superscalers don’t have the expertise, the time or the interest to go and test hundreds of different liquids and setups to see if they’re a viable option. In terms of promoting wider adoption of the technology – it was never going to happen that way,” explains Brink. “Shell was one of only two big companies that had any real expertise and relevance in that domain, so it was a no-brainer, we had to reach out and get them on board.”

“This was a really exciting opportunity for us at Shell to be involved. We saw the main industrial players putting their brains together, streamlining specifications, developing best practices and creating great milestones. We also saw and believed in the innovation and the disruptive nature of this technology,” remembers Eduardo de Azevedo, Production Application Specialist at Shell. “Not only does it have the potential to change the data center industry, but from an environmental-impact and emissions-reduction perspective, it perfectly aligns with our aim to provide lower-carbon solutions to customers. That’s why Shell joined OCP as a platinum member as of August 2020. We want to establish ourselves as the number one, single-phase immersion cooling fluid provider in this exciting domain.”


Asperitas has really been pushing to make a name for itself and shed light on the new possibilities in the data-center-cooling market. For a few years now, the scale-up has been at the cusp of breaking in and drastically disrupting the industry with its technology. Now it seems, they’ve caught the attention of the industry, from OEMs to integrators and even leading enterprises like telecommunication specialists and hyperscale cloud providers. Not only have they been named one of the energy sector’s top global innovations of the decade by the World Economic Forum, but recently, OCP officially recognized Asperitas’ Open Cassette as an OCP Accepted Product Accessory, a real milestone for the company.

Their system, which requires little more than a standard power outlet and a water line for operation, stores the IT deep into a fluid bath, all contained within its own housing. The IT is then cooled through the process of natural convection where the liquid can absorb up to 1,500 times the heat energy compared to more traditional air-cooling solutions, potentially slashing the energy footprint of data centers in half. More interesting yet is the fact that nearly all the waste heat energy is captured in the liquid and can be transferred and reused – making it an even more sustainable option.

“One of the limiting factors that we used to have in the industry was the fact that there’s not a single, global liquid supplier who was able to set a frame of reference for the immersion cooling industry,” recalls Brink. “This is where Shell is filling in that gap. Their ability to design to purpose and make these liquids available for the entire industry is a big step.”

Asperitas module inside detail

Gas to liquids

For its part in the collaboration, Shell has taken on the responsibility of engineering the specialized fluid used in the immersion cooling process. Shell Immersion Cooling Fluid S5 X is a synthetic, single-phase fluid developed specifically for immersion-cooled data servers. The fluid uses Shell’s unique gas-to-liquids (GTL) technology and has been optimized for Asperitas’ natural-convection-driven immersion cooling servers but can also be used in servers with pumps. The fluid is designed to reduce energy costs and emissions through its high cooling efficiency, excellent flow behavior and thermodynamic properties. Shell Immersion Cooling Fluid S5 X is compatible with most commonly used server materials and, being non-corrosive and virtually free from sulphur, nitrogen and aromatics, ensures high server reliability and lifetime.

“The fluid meets US and EU Pharmacopeia purity requirements, has an extremely low volatility and is non-evaporating, thus ensuring a safe working environment while also being sustainable by its non-ozone depleting nature,” illustrates De Azevedo. “But our goal is to be more than only fluid producers, we want to be a technology leader that guides and partners with other industry leaders to create new technological solutions in a more efficient and eco-friendly manner.”


As Asperitas’ solution for immersion cooling continues to gain traction, the company is working hard to show OEMs not only what its system is capable of, but how it can be optimized to fit specific needs and achieve full efficiency potential. That’s why it launched its own three-step certification process for qualifying IT for immersion. The first step is an extensive feasibility study, consisting of mostly paperwork, looking into the details of system needs, a thermal analysis and finally to establish a basic design for the system itself. The second step is building a prototype, running a material analysis and verifying the thermal performance of the system. The third step is putting the IT through duress. The goal is to find out how the equipment acts over a lifetime of maintenance experience, from disassembly and reassembly to knowing how it will react to liquid getting in weird places – it’s a comprehensive report where everything is recorded.

“This requires very close collaboration with the OEM, system integrator or, on rare occasions, the customer that requests the certification. There’s no sales approach here, no marketing sauce, it’s purely a service that we offer. We provide this extensive data and show how the system can be tailored to a company’s specific needs,” explains Brink. “We document every step of the process to give the partner a thorough final report because it’s important to show that the system is performing efficiently for each setup. The customer needs to benefit from the advantages that immersion can offer. Then they can decide if they’re ready for adoption.”