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AI workloads are changing how data centers get built. The servers that train and run large models draw far more power per rack than conventional IT equipment, and that heat has to go somewhere. For the engineers who design a facility’s mechanical, electrical, plumbing and fire protection (MEP/FP) systems, this shifts the main design questions: how to cool racks that air alone cannot handle, how to deliver power without single points of failure, and how to build a facility today that can still serve tenants whose requirements will look different in five years.
Cooling: air and liquid in the same building
Air cooling is not going away, but it is no longer the only option a design has to support. Many new facilities are being built so that a conventional air-cooled hall can sit next to, or later be converted into, a high-density liquid-cooled space.
One example is a pair of new two-story, 36 MW co-location data centers AHA designed in Arizona for a confidential client. Both use a central air-cooled chiller plant with redundant distribution. In the second building, that plant serves a high-density, liquid-cooled tenant fit-out, with a secondary fluid network designed to carry heat away from the racks and a design that accounts for Arizona’s extreme summer temperatures.
Mixing approaches is not new for hyperscale operators. AHA’s design for eBay’s Quicksilver data center in South Jordan, Utah, a 16 MW, two-story facility, used both air and liquid cooling in different areas, supported concurrently maintainable racks at 30 kW per rack and above, and was planned to grow from a 4 MW day-one load to 30 MW. Its primary power source was 8 MW of fuel cells.
Free cooling and lower PUE
Higher densities make energy efficiency harder, because more of a facility’s power goes to removing heat. Designs that use outside conditions for “free” cooling reduce that share and lower power usage effectiveness (PUE).
For eBay’s Mercury data center in Phoenix, a 12 MW modular facility, AHA used hot water cooling, which allowed free cooling year-round despite the desert climate. At Digital Crossroads in Hammond, Indiana, where a former coal-fired power plant is being converted into a 100 MW data center campus of more than one million square feet, the design draws on Lake Michigan water and cool ambient air through indirect airside economizers. The first building, about 100,000 square feet, is designed to scale to 20 MW with flexible rack densities and no raised access floor.
Power and redundancy
Electrical design is where data center owners decide how much downtime risk they will accept. At CyrusOne’s Phoenix complex, which includes a 10 MW, 100,000-square-foot data center, AHA designed the electrical system so the owner could offer N, N+1 or 2N redundancy within the same footprint. The design included a below-grade duct bank from an on-site 110 MW substation, 300 kVA dual-input PDUs with automatic transfer switches, and generators pre-wired for added capacity.
Being able to offer several redundancy levels in one building matters more as AI tenants arrive with requirements that differ from traditional enterprise customers.
Modeling and commissioning before the servers arrive
Two steps reduce risk before a facility goes live. Computational fluid dynamics (CFD) modeling simulates airflow and temperatures inside the white space and around the building, so hot spots and recirculation problems are found in design rather than after equipment is installed. On the first of the Arizona projects, AHA ran both internal and external CFD studies.
Commissioning then confirms that installed systems work as designed. For mission critical work, that includes foreign object and debris inspections before systems are energized, to reduce the risk of equipment damage, and phased MEP commissioning from L2 through L6 on smaller edge data centers of around 1 MW.
Where the work is moving
Northern Virginia remains the largest data center market in the country, and AHA opened an office in Ashburn, Virginia in January 2026, led by Partner and Managing Director Jennifer Mitarotonda, PE, LEED AP. The firm’s recent work in the region includes multiple new hyperscale data centers for confidential clients in Virginia.
The technology inside data centers will keep changing faster than the buildings around it. Facilities designed with scalable cooling, flexible redundancy and room to add capacity are the ones most likely to serve the next generation of tenants without a major rebuild.
