Data centers consume an estimated 2-3% of global energy. Naturally, they have a huge carbon footprint, especially in areas with dominant fossil fuel-based energy. Now, with the rise of Artificial Intelligence (AI), power consumption is posed to increase to 681 TWh (terra watt-hours) of which 90 will be from AI data centers. Liquid cooling is being proposed as a possible solution.
Although infrastructure consumes a major percentage of energy, cooling the facility and the equipment is also a big part of data center energy consumption. Liquid cooling is an innovative way to cool infrastructure without using too much energy. While it’s somewhat novice for the mainstream data center space, it’s slowly becoming the go-to for energy efficiency and emissions reduction.
In this article, we’ll discuss the advancements in liquid cooling and how they can make data centers more energy efficient, ideally with a smaller carbon footprint.
Here’s a quick explanation of liquid cooling.
Liquid cooling involves using liquids to dissipate heat from electronic components in data centers, such as servers and storage racks. Unlike air cooling, which relies on circulating air to remove heat, liquid cooling employs high thermal conductivity fluids to absorb and transport heat away from servers and other hardware.
The concept of liquid cooling dates back to the mid-20th century. It was initially applied in those gigantic mainframe computers to manage heat. Air cooling became the standard as computing technology evolved due to its simplicity and lower upfront costs. However, the resurgence of liquid cooling in recent years is driven by the increasing demands of modern data centers and the limitations of air cooling in handling high-density workloads. Also, traditional cooling methods that use air conditioning units and HVAC systems consume significant energy.
Liquid cooling systems operate through various methods, but these methods can be categorized into two.
This approach utilizes cold plates attached directly to heat-generating components like CPUs and GPUs. Coolant (liquid) circulates through these plates, effectively absorbing heat. Direct-to-chip cooling can remove approximately 70-75% of the heat generated by equipment in a rack. The rest must be removed with other methods, such as air cooling.
Direct-to-chip cooling can be single-phase or double-phase. In the former, the coolant doesn’t change its state. In the latter, it does, which makes it better, as it has lower leakage risks.
This method completely submerges servers in dielectric (non-conductive) fluid within specially designed tanks. The fluid absorbs heat directly from the components. Single-phase immersion cooling involves circulating the heated fluid through a heat exchanger to dissipate heat before returning it to the tank. It’s essentially soundless, compared to air cooling methods, which can be as high as 80 dB.
Within immersion cooling, you have single-phase and two-phase options. Again, the difference is the same—a change of state for liquid coolant. The coolant can turn into gas, condense, and fall back into the tub again.
Leading technology companies have already implemented liquid cooling to enhance data center performance and sustainability. Here are some notable examples:
From a sustainability standpoint, liquid cooling is better than air cooling because it uses less energy. Less energy consumption means fewer emissions (especially in cases where fossil fuel energy is used).
Vertiv, a company that provides data center liquid cooling solutions, partnered with NVIDIA to conduct several studies and compared liquid and air cooling technologies. It conducted four separate studies with varying combinations of the two cooling methods.
Here’s what they found that confirmed liquid cooling is superior to air cooling in terms of energy usage and infrastructure performance:
Besides energy efficiency, liquid cooling can also help reduce the footprint of the data center. According to a research published in Applied Thermal Engineering, immersion cooling can reduce the infrastructure size by one-third compared to air cooling.
As data centers evolve to meet the escalating demands of HPC and AI, efficient cooling solutions have become necessary. There’s also the growing pressure internally and externally for data centers (and their customers) to bring down their emissions. That means cutting down on energy consumption.
Let’s look at the benefits of liquid cooling in data centers in more detail:
Liquid cooling systems significantly reduce the energy consumption associated with cooling data centers. Using liquids' superior thermal conductivity, these systems can decrease cooling power usage by up to 90% compared to traditional air conditioning methods. This reduction lowers operational costs and contributes to a more sustainable and environmentally friendly data center infrastructure.
The energy efficiency translates into cost savings. Check out the cost comparison below between air cooling and liquid cooling.
PUE is a critical metric for assessing data center efficiency. Liquid cooling technologies have been instrumental in achieving lower PUE ratios. For instance, data centers utilizing liquid cooling have reported PUE values as low as 1.02 or 1.03, indicating minimal energy waste.
The increase in AI and machine learning applications has increased server densities and energy demand. Liquid cooling, by design, addresses this issue by efficiently managing the heat generated in high-density environments.
Immersion cooling, for instance, can pack in more servers per rack. It also eliminates the need for internal fans, which not only saves power but also helps increase density.
Implementing liquid cooling systems in data centers offers significant benefits in managing heat and improving energy efficiency. However, transitioning from traditional air cooling methods presents several challenges that enterprises must carefully consider.
Adopting liquid cooling often requires substantial upfront capital expenditure. While some analyses suggest that liquid cooling does not incur a cost premium at similar rack densities over air cooling, the need for infrastructure modifications can elevate initial costs.
For example, integrating liquid cooling may necessitate changes to spatial design, plumbing, and chiller lines, which can be complex and expensive.
Liquid cooling systems demand specialized maintenance and operational knowledge. Data center staff must be trained to handle fluids, manage cooling loops, and detect potential leaks or equipment malfunctions.
Maintaining these systems can be complex, leading to increased operational costs. Enterprises may need to hire specialists for maintenance, adding to their payroll. Data centers may also need to provide ongoing education and training.
The introduction of liquids into data center environments poses the risk of potential leaks. And fluids aren’t the best thing for the internal components of equipment. Any possible damage from leaking liquids can also lead to significant downtime.
The good thing is that work is underway to make liquid cooling less risky. Immersion cooling, for example, is less prone to leakages, making it a safer choice.
Additionally, data centers need to consider corrosion and the physical security of cooling systems.
The lack of standardized protocols for liquid cooling technologies makes it difficult for enterprises to adopt them. First of all, there are variations in system designs and implementation approaches. Secondly, adopting it means significant infrastructure changes and possibly interoperability issues. Integrating this cooling type with existing data center infrastructure can be difficult.
We need a standardized approach with blueprints that can be recreated at scale worldwide. Also, the equipment may need to be redesigned to be more readily integrated with liquid cooling.
The global data center liquid cooling market is growing quickly. According to one estimate, its value will rise to $21.14 billion in 2032 from just $2.84 billion in 2025 (a CAGR of 33.2%). That means liquid technologies are getting adopted across the industry.
If you represent the leadership in a data center, it’s time to rethink air cooling. Develop a plan to transition to liquid cooling according to your needs and budget. It may be a significant investment, but it has the potential to reduce energy expenditures in the long run.