April 13, 2024
Ict

Emerging Technology: Liquid Immersion Cooling for Data Centers


Data centers have become vital infrastructure for modern businesses and organizations. However, with growing computing needs and cloud services, data centers are facing challenges in efficiently managing the massive heat generated by servers and IT equipment. Conventional air cooling methods are struggling to remove heat from dense server racks effectively. This has led to the exploration of innovative liquid cooling techniques for data centers. One emerging technology gaining attention is total server immersion cooling which involves submerging entire server modules in a non-conductive dielectric liquid. Let’s explore how this technology works and its potential benefits for the data center industry.

What is Liquid Immersion Cooling?

In Liquid immersion cooling servers are placed inside watertight containers and fully immersed in a specially engineered dielectric liquid. This liquid serves as both the coolant and insulating medium. Typically, the liquid used is a fluorocarbon-based fluid which is non-conductive, non-corrosive, fire-resistant, and has high thermal transfer properties. The liquid filled containers housing the servers are then placed inside larger tank-like structures within the data center. Coolant is continuously circulated within these tanks to transfer heat from the submerged servers to external heat exchangers.

The heat exchangers further cool down the liquid using standard chillers, cooling towers, or other external heat rejection methods. The cooled liquid is then pumped back into the server tanks, thus enabling a closed-loop cooling cycle. Sophisticated control and monitoring systems ensure optimal coolant flow and temperature regulation across individual server containers. The density of the liquid also allows it to effectively wick heat away from all surfaces of complex server components evenly.

Potential Advantages of Liquid Immersion Cooling

Compact Design: Since servers can be fully packed together in liquid filled tanks, liquid immersion cooling allows for extremely dense server deployments without any air space wastage between racks. This significantly improves real estate utilization within the data center.

Higher Heat Transfer: The high thermal conductivity of dielectric coolants enables efficient transfer of heat from even the smallest components inside densely populated servers. Some studies show liquid cooling can remove over 200 kW of heat per rack— almost three times more than conventional air cooling.

Improved Reliability: Fully submerging servers in liquid protects them from dust, air leakage, and other environmental issues. This enhances the lifespan of components. Additionally, liquid wicks heat more evenly reducing hotspots and component failures.

Energy Savings: With more effective heat removal, liquid immersion allows servers to run at much higher power densities without overheating. This accelerates workload consolidation leading to better infrastructure utilization and energy efficiency. Some reports found PUE values as low as 1.06 with this technology.

Lower Operating Costs: Due to reduced server sprawl, optimized rack utilization, and lower energy use—data centers using liquid cooling may experience 25-40% reduction in total cost of ownership over a 10-year lifecycle. Maintenance requirements are also lowered without fans and filters.

Reliable Cooling During Power Outages: External power is only needed for coolant pumps and heat rejection—the liquid inside server tank acts as a thermal battery keeping components cool during brief outages. This ensures uninterrupted operation.

Drawbacks and Challenges

Higher Upfront Cost: Total immersion cooling solutions require specialized server equipment, liquid containment mechanisms, pumping infrastructure etc—initially increasing capital expenditure over traditional cooling methods. However, the long term savings offset this.

Complex Deployment: Setting up large-scale liquid cooling systems within live data halls is more complex than air-based retrofits. Detailed design, installation, and maintenance best practices need adhering to for reliable operations. Proper staff training is important.

Single Point of Failure: A comprehensive cooling plant failure could potentially impact all servers immersed within the same liquid tank increasing risk of downtime. However, most solutions have redundant systems to prevent such scenarios.

Material Compatibility: Ensuring complete compatibility between dielectric coolants, server components, and other construction materials over long operational periods needs extensive evaluation and testing.

Spill Containment: Effective spill control mechanisms are vital inside data halls housing large volumes of liquid coolants to prevent leaks from causing electrical/facility issues. Secondary containments may be needed.

Standardization: Lack of open industry standards has slowed wider adoption, though initiatives are addressing this. However, a more vibrant ecosystem of compatible products could accelerate market growth.

Conclusion
Liquid immersion cooling shows great promise in addressing the thermal challenges facing ever-growing hyperscale data centers. Its ability to support higher server densities makes it well-suited for facilities housing thousands of servers. Though initial outlay is substantial, long term cost savings and reliability benefits make it attractive for large cloud and colocation providers. As techniques mature, standards develop, and applicable use cases expand—many predict this emerging approach will significantly transform data center design best practices worldwide over the next decade. Widespread adoption will rely on overcoming current barriers through open collaboration within the industry.

*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it