Revitalizing Legacy Data Centers with Self-Contained Liquid Cooling

Once epitomizing technological prowess, many legacy data centers now grapple with the challenges of integrating contemporary cooling solutions. These facilities were designed in an era where cooling demands were vastly different. But as we witness reduced energy costs, a push for better PUE, and heightened environmental consciousness, liquid-assisted air-cooling technology emerges as a beacon of hope.

For decades, air cooling was the undisputed champion of data center cooling solutions. From the 2000s to the mid-2010s, the IT industry reveled in the consistency this method offered. A report by the Uptime Institute indicates that during this period, server heat output changes were marginal, ensuring that air cooling was mostly adequate.

However, as we transitioned into the 2020s, we faced an inflection point. Servers became more powerful, and the demands on data centers soared. This evolution meant that traditional air-cooling methods were no longer sufficient. The Uptime Institute highlighted an increase in power density of racks, leading to a more pronounced need for efficient cooling solutions. Their 2023 Cooling Systems Survey further emphasized this, revealing that 68% of respondents saw higher rack densities as the compelling reason behind considering direct liquid cooling. Furthermore, in a Data Center Knowledge article, Omdia’s Cloud and Data Center Research Practice Director Vlad Galabov report preliminary data center cooling equipment data points indicate a sharp increase in liquid cooling deployments, citing figures supplied by thermal management equipment vendors.

Enter liquid-assisted air cooling—an innovative hybrid solution that combines the strengths of two cooling methods. This approach merges the efficiency of direct-to-chip liquid cooling with the reliability inherent in traditional air cooling. This dynamic combination effectively manages heat dissipation even in densely packed computing environments. The technique utilizes sealed liquid cold plates to directly target the processors, capturing the generated heat. This heat is then seamlessly channeled to a heat exchanger, optimizing its release. The research paper titled “Power Usage Effectiveness Analysis of a High-Density Air-Liquid Hybrid Cooled Data Center” highlights a significant reduction in server-level fan power consumption by using this cooling method, particularly at higher temperatures (SAT). Furthermore, opting for a hybrid design over pure air cooling diminishes the demand for air cooling equipment, while the energy requirements for liquid cooling replacement are substantially lower.

One of the challenges data centers face today is the speed at which server technology evolves. With most data centers having a 15–20-year lifespan, and racks with an average lifespan of about five years (as indicated by the Uptime Institute), the need for adaptable solutions becomes paramount.

Traditional liquid cooling, with its infrastructure-wide requirements, often isn’t agile enough. In contrast, liquid-assisted air cooling enables the simultaneous existence of liquid and air-cooled servers within a single rack. This compatibility ensures that as servers are upgraded or replaced, the cooling infrastructure remains relevant and efficient.

Upgrading a legacy data center with liquid cooling often requires significant investments in terms of finances, time, and workforce. Immersion cooling technologies, which may involve an entire facility redesign and the installation of new equipment, can be particularly demanding. According to Vito Savino, the leader of ABB Power Conversion, the decision to adopt immersion cooling is not a simple one, as he points out:

“If the transition were a simple plug-and-play, adopting liquid immersion cooling across the globe would be a no-brainer. However, the time, money, and manpower that must be spent on adoption make the decision a significantly more difficult one.”

On the other hand, liquid-assisted air cooling offers a contrasting approach to immersion cooling. It provides a streamlined and easily integrated liquid cooling system that seamlessly fits into standard server infrastructure. It doesn’t require specialized servers, racks, or elaborate setups to start reaping its benefits. Furthermore, this approach involves minimal downtime during installation, allowing for a gradual cooling infrastructure upgrade—one step at a time. This feature proves particularly beneficial for industries such as high-frequency trading or healthcare, where even a brief period of downtime could have serious consequences.

Several IT giants like Microsoft, Meta, and Google are rapidly expanding their campuses to support the latest advancements in technology. In a time of high demand and limited supply, it’s crucial to optimize existing facilities and reduce capital costs. Liquid-assisted air cooling revitalizes legacy data centers, providing the flexibility needed to accommodate high-density servers. By removing cooling barriers in these facilities, enterprises can optimize their entire campus and effectively manage diverse workloads across multiple sites. Furthermore, this solution maximizes compute per floor tile, consolidating compute power into the smallest package possible. With this approach, enterprises can extend the lifespan of their legacy data centers and enhance performance all within the same square footage.

Cooling systems often come under scrutiny for their substantial energy consumption, accounting for a significant proportion of total energy usage in data centers (typically ranging from 30% to 55%) The initial expenses linked to transitioning to liquid cooling, encompassing investments in new servers, plumbing, and cooling distribution units (CDUs), further compound the already considerable cost of upgrading legacy data centers.

The self-contained, liquid-assisted air-cooling system effectively mitigates both capital and energy expenditures through its closed-loop design and targeted cooling approach. By harnessing the benefits of both air and liquid cooling, this innovation eliminates the necessity for CDUs, a cost usually associated with liquid cooling implementation, thereby reducing upfront expenses by a noteworthy 50%.

This alternative not only yields financial savings but also offers enduring energy and operational advantages. Liquid-assisted air-cooled system effectively curtails fan speed by 50%, resulting in a substantial energy consumption reduction of up to 4kW per rack. Additionally, the system addresses the challenge of noise pollution by minimizing fan operation, cultivating a quieter operational environment, particularly beneficial in residential areas. Furthermore, it extends the longevity of data center equipment, curbs technological waste, and diminishes manufacturing carbon emissions by maintaining stable and cooler operational temperatures.

The dynamic realm of data center management demands solutions that are scalable, efficient, and sustainable. Liquid-assisted air cooling presents a holistic solution to the challenges faced by modern data centers. By fostering an environment that maximizes space utilization, ensures energy efficiency, and curtails costs, this innovative cooling methodology is set to reshape the future of data center infrastructure. As we navigate the digital future, ensuring our data centers are equipped to handle the demands of tomorrow will be instrumental.