As data centers expand to support AI and other high-density computing workloads, facility managers face growing pressure to reduce both energy consumption and water use. Choosing between water-intensive and water-free cooling systems is no longer a simple efficiency calculation — it requires balancing regional water availability with long-term sustainability goals.
In this manufacturer roundtable, Facility Maintenance Decisions spoke with data center cooling system manufacturers about how facility teams can evaluate cooling trade-offs and explain how evolving sustainability expectations are reshaping HVAC design.
FMD: Water use is becoming a growing concern in many regions. How should facility managers evaluate the trade-offs between water-intensive and water-free cooling approaches from a long-term operational and sustainability standpoint?
“Facility managers are increasingly taking a more holistic view of cooling decisions. Water-free systems may reduce onsite water use, but often increase energy demand, especially during periods of peak heat.
By contrast, closed-loop liquid cooling systems, when properly designed, can deliver higher heat transfer efficiency, reduce evaporative loss and enable heat recovery, improving both water and energy performance across the system’s lifecycle.
The key is understanding the trade-offs across the entire facility. This includes efficiency, uptime, local water availability, and long-term resilience, instead of focusing too heavily on any one metric.”
— Matt Johnson, business development manager, building services, Xylem
“Facility managers evaluating water-intensive versus water-free cooling need to balance energy efficiency, water availability, regulatory pressure, and long-term resilience rather than optimizing a single metric. Water-based cooling approaches can reduce electrical energy use in suitable climates, but increase exposure to water scarcity, cost volatility, and regulatory constraints.
Water-free or low-water approaches reduce dependency on local water resources and simplify compliance in water-stressed regions but may require higher electrical input and can be less effective at very high heat densities. In practice, that often means designing for low water usage effectiveness (WUE) through closed secondary loops, dry or hybrid heat rejection, and higher allowable coolant temperatures, which together can meaningfully reduce both cooling energy and water consumption at the system level.
Over time, more resilient strategies tend to align cooling selection with regional conditions while maintaining flexibility to adapt to seasonal variation, workload changes, and evolving sustainability requirements across both energy and water systems.
Ideally, hyperscale operators rely on closed-loop systems, with the TCS loop designed as a sealed system to prevent external contamination. The facility water system (FWS) and condenser water system (CWS) are typically managed through established water treatment programs, with DCOPS teams responsible for ongoing monitoring and maintenance to ensure system reliability and water quality.”
— Mike Donahue, senior solution architect, Schneider Electric
FMD: How are evolving sustainability expectations, from both regulators and internal stakeholders, changing the way HVAC systems are designed, operated and maintained in data centers?
“Sustainability expectations are reshaping how operators think about cooling performance over the long term. There is now greater focus on understanding where water and energy are used, how systems perform over time, and where adjustments can improve efficiency without affecting uptime.
This is driving increased interest in technologies such as connected controls, smart pumping, high-efficiency heat exchangers and monitoring platforms that provide real-time visibility into flow, temperature, pressure and overall system efficiency. Ultimately, the goal is to build a more adaptive cooling infrastructure. Hydronics-based systems are well suited to evolving operational and sustainability demands.”
— Matt Johnson, business development manager, building services, Xylem
“Evolving sustainability expectations from regulators and internal stakeholders are shifting HVAC design and operations toward broader environmental performance outcomes, including energy efficiency, water use and carbon impact across the full lifecycle. This is driving tighter integration between IT and facilities planning, more efficient cooling architectures and increased use of technologies that reduce both energy and water consumption while supporting higher and more variable compute densities. Operationally, there is growing reliance on real-time monitoring, automation and data-driven optimization rather than static control strategies.
Maintenance practices are also evolving toward predictive and condition-based approaches, with increased focus on refrigerant management, system efficiency over time, and compliance with more rigorous sustainability reporting requirements. Metrics such as power usage effectiveness (PUE), water usage effectiveness (WUE) and carbon usage effectiveness (CUE) are increasingly tracked together rather than in isolation, and condition-based maintenance, including coolant chemistry monitoring, differential-pressure leak detection on liquid loops and analytics across the installed base, is becoming a baseline expectation rather than a differentiator.”
— Mike Donahue, senior solution architect, Schneider Electric
Jeff Wardon, Jr., is the assistant editor for the facilities market. With more than three years of experience, he covers topics including technology, wellness, sustainability and emerging industry trends.
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