Traditionally, data centers operated by cloud providers like AWS, Azure, and Google Cloud have relied on air conditioning and liquid cooling to keep servers and other equipment from overheating.
However, these cooling methods are inefficient, expensive, and resource intensive. And this is especially true in the context of facilities located in tropical climates (for example, Hong Kong or Singapore), which are locked in a constant battle with the environment.
In recent years, attention has focused on developing new systems that can cool data centers more efficiently and sustainably. While a few different techniques look promising, one in particular stands out: two-phase liquid immersion.
In this system, the server racks are completely submerged in reservoirs of non-conductive fluid. When the material begins to generate heat under load, the fluid begins to boil and rises to the top of the tank. In the second stage of the process, a condensing coil returns the gas to a liquid state, which falls back into the chamber below, and so the cycle continues.
Leading the charge in this space is a company called LiquidStack, which offers dip tanks for a variety of rack sizes. Although its technology is not yet widely used, it is starting to generate interest from some of the world's largest hyperscalers.
“Change is always difficult in the data center industry; the industry is risk averse and slow to change,” said Joe Capes, CEO of LiquidStack, in conversation with TechRadar Pro. “But I predict we will see the first large-scale cloud deployment using just a two-phase drop over the next twelve months. "
a new identity
Founded in 2012, LiquidStack started life under a completely different identity: Allied Control Ltd. At the time, the ambition was to build the first Bitcoin mining data center in Hong Kong, when the cryptocurrency was trading at just €13 per unit. .
After rejecting all available cooling methods for cost reasons, Allied Control was forced to develop its own technique in conjunction with a company called 3M, which now manufactures the fluid used in LiquidStack dip tanks.
In other words, liquid immersion began as a means to an end, a utility in pursuit of a separate goal. But in recent years, new refrigeration technology has become the main focus.
While Allied Control still believes that the crypto industry is a major addressable market, the company made the decision to pivot last year to focus on high-performance computing (HPC), data center, and edge. As part of this process, the company was renamed LiquidStack.
When asked about the rationale for the name and leadership change, Capes explained that the team had identified emerging opportunities that they were well positioned to capitalize on.
“We wanted to do two things: take advantage of the net traction that liquid immersion had gained in the data center industry since around 2017, and also separate our business from the Bitcoin price,” he said.
“I think it was a really smart choice, as it allowed us to diversify our market segmentation into high-growth areas, while taking the opportunity to apply ourselves in certain crypto scenarios, where the adjustment are bueno."
The strategy appears to be paying off; the company is growing rapidly and recently added Microsoft to its list of clients. The next challenge facing LiquidStack is bringing two-phase liquid immersion to market on a large scale.
the perfect fluid
The most important ingredient in the immersion cooling equation is the dielectric fluid. These compounds have a very specific set of attributes, meaning they can cool a computer's hardware extremely efficiently, but without causing damage.
LiquidStack currently uses a fluid called Novec 7000 for its dip tanks, which is manufactured by 3M. The fluid is non-toxic, non-conductive, and has a low boiling point of just 34 degrees Fahrenheit (93 degrees Celsius), which is perfect for two-stage immersion cooling scenarios.
Unlike oil-based immersion, fluids like Novec 7000 are also non-flammable, so there's less risk of a data center igniting, with dire consequences for web hosting providers' customers., Bare Hosting metal, server hosting and colocation. .
“These fluids were originally designed to clean computer components on printed circuit boards and internal servers,” Capes explained. "And they are still widely used as mild solvents in the semiconductor industry."
“When you take a server out of that liquid, it dries up in 30 seconds. This is a great advantage from the point of view of ease of maintenance.
However, the same attributes that make these fluids excellent solvents also pose challenges in a data center environment; the high rate of evaporation means that it is easy to lose large amounts of liquid and quickly.
For this reason, LiquidStack tanks are tightly sealed in operation (Capes says no dust or air can get in) and are designed so that only a minimal amount of liquid is lost when material is shifted in and out.
However, the next generation of dielectric fluids is the most exciting. According to Capes, companies like 3M, Chemours and others are on the verge of developing near-zero global warming potential (GWP) fluids.
By replacing ozone-depleting data center refrigerants (such as R410A and R407c) with zero-GWP dielectric fluids and replacing energy-intensive immersion cooling techniques, LiquidStack expects to significantly reduce the environmental impact of data center industry. of data. .
“This year alone, data centers will consume 300 billion liters of water to reject outside heat. The ability to bring that number down to zero is transformational,” Capes said.
“My ambition is to get to a day where there is no evaporated water for heat rejection. That alone could bring great benefit to the planet. "
Performance improvement
However, the ability to make data center facilities more sustainable is by no means the only benefit of liquid immersion; New research from Microsoft shows that the technique also has the potential to unlock huge performance gains.
“Computing capacity has always been on the rise due to constant technological improvements in the semiconductor manufacturing and packaging industry. This growth in computing capacity is often accompanied by a sharp increase in heat flux density,” the researchers explain.
“Advanced air cooling technologies slow down after a certain level of heat flow and would require larger heat sinks resulting in huge airflow, which may not be desirable from an operation standpoint. from the data center. Therefore, research into advanced thermal management techniques is an absolute must. "
According to data compiled by Microsoft, which is experimenting with LiquidStack dip tanks at its Azure facilities, some server chipsets can be overclocked by more than 20% thanks to the superior thermal management they offer.
The ability to complete demanding AI workloads significantly faster with immersion cooling could have major ramifications for just about everything from finance and pharmacy to manufacturing and beyond. We may be done with Covid vaccines even sooner, for example.
As Capes explains, immersion also opens up opportunities in the context of rack design and facility layout. Because there is no longer a need for bulky heat sinks, more servers can be squeezed into a much smaller area.
In theory, this means that the compute density of a data center facility could be increased by a significant margin, without the need to upgrade server processors or expand physical space.
There are also important branches in the suburbs, where space is at a premium, but more and more computing is expected in the coming years. The ability to squeeze more computing power into a more compact footprint could enable a range of new advanced computing use cases in suburban and even urban environments, reducing latency to near zero.
Capes even says that liquid immersion cooling may spill over into the consumer sector to some degree, possibly paving the way for the next generation of monster gaming rigs.
“Basically, this is a really exciting time. I think change is difficult, but it is very real and we are seeing great traction in the market,” added Capes.
“We are witnessing a true renaissance in the semiconductor and computer hardware industry, which will only accelerate immersion in liquids. "
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