As demand for compute capacity grows, chipmakers are packing more transistors into their chips than ever. This has helped many chipmakers push core counts to 40, 64, and even 128. However, this comes at the consequence of higher power consumption and by extension hotter data centers.

Both Intel and AMD’s latest and greatest data center processor families are inching closer to 300 watts per socket, and it's not uncommon for a single server to employ four or more CPUs. Add it up and that’s not only a lot of power, it’s also a lot heat that needs to be dissipated to keep those chips running at peak performance.

To accommodate, server chassis are made bigger to fit bigger heatsinks and more cooling fans, but this also means data centers can fit fewer servers on each rack. It’s this vicious cycle that LiquidStack CEO Joe Capes aims to address. His company specializes in liquid cooling technologies common it high-performance compute and Bitcoin mining operations: two-phase liquid immersion cooling.

“Two-phase immersion cooling has been used in high-performance computing applications getting back to the last seven, eight years,” he said. “I think there's been about five years of practical use case for Bitcoin mining applications, but now we see this technology being adopted by some of the major cloud computing and cloud services companies.”

To be clear, liquid cooling is nothing new in the data center, and original equipment manufacturers (OEMs) are well aware of the challenges faced by data center operators when it comes to cooling. Dell Technologies last month launched a series of liquid-cooled server chassis.

However, unlike traditional liquid cooling systems, which use water, or in some cases refrigerants, flowing through specially designed heatsinks and chassis to move heat away from critical components, liquid immersion cooling is a bit more complicated.

Instead of a traditional server chassis in a standard 42-unit rack, servers are stripped down to their bare components and slotted vertically into a couch-sized tank that, when open, looks sort of like a deepfrier.

This tank is filled with a fluid that’s harmless to electronic equipment and is specially engineered to boil at 122-degrees Fahrenheit, which is about 50-degrees Celsius. “These fluids were originally created to clean the printed circuit boards and components that are commonly used in IT and semiconductor manufacturing,” Capes explained.

As electronic components like the CPU heat up, it causes this liquid to boil off, thus cooling them in the process. Vapors are then condensed back into a liquid on pipes carrying warm water pumped in a closed loop from an external plant.

“The benefit is: You're not consuming any energy to reject the heat inside the data center,” Capes said. “There's no noise, and the only power that's consumed is by the pumps that move the [water] from the outside mechanical plant to our data tanks.”

If all this sounds decades off, it isn’t. Microsoft, earlier this month, announced it was trialing the technology at a data center in Quincy, Washington.

“We are the first cloud provider that is running two-phase immersion cooling in a production environment,” boasted Husam Alissa, principal hardware engineer on Microsoft’s advanced data center development wing, in a statement.

Microsoft reports that the technology has allowed them to cut power consumption by between 5% and 15%, while Capes claims that a data center built entirely around immersion cooling can cut power consumption by as much as 55% by eliminating inefficient air handling units.

The advantages of liquid immersion cooling go beyond cooling too, Capes explained. “One of the brilliant things about today's immersion liquid cooling is that you can drastically condense size and the form factor of IT compute gear,” he said.

In a traditional air-cooled server chassis, as soon as CPUs push past about 225 watts of power, OEMs are forced to increase the size of the chassis to accommodate larger cooling fans and heatsinks.

But using LiquidStack’s data tanks, servers only need to be fitted with a slim, 1-millimeter heat sink. This means systems, even those with multiple CPUs or GPUs, can be crammed down into the equivalent of a single rack unit’s worth of space.

“We talking about reducing the height of a two, four, or five [rack unit] server back down to a 1U server,” he said. “You can actually pack the boards within 2.5-millimeters of each other … That’s why we can get such incredible density in the same form factor as a traditional IT rack.”

Between the power savings from cooling and the tighter densities, Capes claimed that a single 48 rack unit data tank can contain roughly 252-kilowatts of raw compute capacity — the equivalent of 30 air-cooled server racks when taking the accompanying air handling equipment into consideration.

Beyond power and compute density, there are ancillary benefits of immersion cooling, such as reducing data center water consumption, and cutting back on the use of raw materials for things like heatsinks and server chassis.

“If data centers this year all adopted two-phase immersion, we'd be able to eliminate the amount of steel that was used to build the George Washington Bridge in New York, three times over,” Capes said.

Additionally, LiquidStack’s data tanks don’t consume any water, and what water is used is contained in a closed loop, Capes said.

“Water has become a bigger concern than energy used by data centers,” he said. “By implementing the technology, the world could save over 300-trillion liters of water per year, just in eliminating the water that's evaporated for heat rejection.”

Microsoft’s decision to explore two-phase liquid cooling coincides with the cloud provider’s efforts to become “water positive,” meaning it will replenish more water than it consumes, by the end of the decade. Additionally, Microsoft aims to transition to 100% renewable energy by 2025, to be carbon negative by 2030, and to wipe out its carbon footprint by 2050.

While two-phase liquid immersion cooling has the potential to reduce power and water consumption, that's not to say it's perfect. Like many common refrigerants, the fluids used in immersion cooling can contribute to global warming if allowed to escape into the atmosphere.

He notes that this has been a major consideration from the very beginning with LiquidStack working with 3M to develop fluids with lower environmental impacts. “We're talking about order of magnitude improvement in global warming potential versus the refrigerants that are being used in data centers today.”

The fluid itself is actually quite safe, Capes claims. “It’s a non-hazardous fluid. The fluid itself is safe, you know for human touch.”

According to Capes, these fluids have global warming potentials (GWP) of between two and 10, making them rather benign compared to refrigerants like R-404A, which is nearly 400-times more potent, according to the California Air Resources Board. The board does not consider refrigerants with GWPs less than 124 to be high environmental risks.

Despite being a relatively low risk, LiquidStack has invested heavily in minimizing losses to the atmosphere.

“The one thing with the fluid is they have a high evaporation rate,” he said. Because of this, “there's a lot of secret sauce that goes into how we manufacturer our data tank, so that they're hermetically sealed, and so that the fluid loss is very, very minimal.”

According to Capes, the technology hits all four pillars of sustainability by “dramatically reducing direct and indirect carbon footprint, lowering or eliminating the use of water for a datacenter heat rejection, and massively reducing e-waste by 30% or more.”

Additionally, the higher compute densities enabled by more efficient cooling could allow data center operators to build smaller facilities with few environmental impacts, Capes said.