Data Center Cooling Plant and Equipment Yard Space: Chillers, Dry Coolers and Cooling Towers

Every watt delivered to IT equipment ends up as heat that must leave the site. Inside the building, computer room air handlers, fan walls or coolant distribution units move that heat into a water or refrigerant loop. Outside, heat rejection equipment dumps it to the atmosphere. That outdoor equipment is what takes site space, and it comes in three main forms: air-cooled chillers, water-cooled chillers paired with cooling towers, and dry coolers (sometimes with adiabatic spray assist).

Unit sizes have grown with campus loads. Trane markets an air-cooled magnetic-bearing chiller that delivers over 850 tons (3 MW) of cooling in one frame and says its capacity per square foot of footprint often reduces the number of chillers needed on site.¹ Water-cooled centrifugal chillers are larger still, with one data center line offered up to 21 MW per package, but they sit indoors in a central plant and need cooling towers outside.¹⁰

• Heat rejection: chillers, cooling towers or dry coolers, usually with N+1 or better redundancy.
• Pumps, piping headers and water treatment, often in a central plant building or on skids.
• Thermal storage tanks, in some designs, to carry cooling through a chiller restart.
• Makeup water, blowdown and chemical storage where towers or adiabatic coolers are used.

How much of each a site needs depends on rack density and cooling type, covered in our guides to air vs. liquid cooling and rack density trends.

The core trade-off is water against electricity. TechTarget’s comparison across three U.S. climate zones shows the tension directly: dry coolers release no water but draw considerably more power to dissipate the same heat than cooling towers.⁵ Cooling towers reject heat by evaporation, which is efficient but consumes water and requires treatment. Under ASHRAE Standard 188, buildings with water systems that can harbor Legionella, including cooling towers, need a documented water management program built on a risk survey, a plan and verification steps.⁶

Large operators are shifting toward water-free designs where they can. Microsoft introduced a design in 2024 that uses chip-level cooling and a closed loop filled once during construction, avoiding more than 125 million liters of water per year per data center by its own estimate. It planned pilots in Phoenix and Mount Pleasant, Wisconsin, with operations scheduled for 2026, and acknowledged that replacing evaporative cooling with mechanical cooling raises energy use.¹¹ Our guide to closed-loop and waterless cooling covers what that means for water supply, and WUE covers how water use is measured.

No public standard gives a square-feet-per-megawatt figure for cooling yards, because the answer depends on unit type, capacity, redundancy and layout. The practical method is to count units and then add clearances. Start from the heat to be rejected, which is the IT load plus fan, UPS and other losses inside the building, then divide by the capacity of the chosen unit at the site’s design ambient temperature, and add redundant units.

Clearances matter more than the unit footprint suggests. YORK’s published minimums for one air-cooled chiller model are 6 feet from the sides and rear to a wall, 4 feet at the control panel end, no obstruction above, and 10 feet between adjacent units, and the company notes that restricted airflow raises power use and reduces capacity, with larger effects on units with more fans.³

As an illustrative example only: a hypothetical 60 MW IT block with about 66 MW of heat to reject, served by 3 MW chillers, needs 22 running units plus redundant units. If each unit and its share of clearances took about 1,500 square feet, 26 units would occupy roughly 39,000 square feet, close to an acre, before pumps, drives and screening. Real numbers come from vendor drawings and the mechanical engineer’s layout.

Air-cooled equipment works only if it can breathe. A CFD study reported by ACHR News found that wider spacing lets discharge plumes separate and rise, lowering intake temperatures, while units placed close to a building wall see higher intake temperatures as hot air is pushed back toward the wall. Screens and architectural enclosures can also restrict airflow, and wind speed and direction affect how plumes disperse.¹² Recirculation cuts capacity on the hottest days, exactly when the plant is most loaded.

Placement is the next decision. Single-story buildings often put chillers or dry coolers on the roof, which saves yard space but adds structural load. Stream Data Centers’ 200 MW expansion in Goodyear, Arizona, for example, was reported to use rooftop air-cooled chillers that required extra checks under the city’s building codes.¹³ Multistory designs flip the problem: Johnson Controls notes that for developers stacking data halls vertically, roof area per megawatt is often the binding constraint, which pushes equipment into ground-level yards.¹⁴

On flat, open sites, orient the yard so prevailing summer winds do not carry discharge air from one bank of units into the next, and keep tall walls and screens far enough away to avoid trapping heat. Our guide to climate and cooling in site selection covers design temperatures.

Planning documents are the best public window into cooling plant size. At a May 2025 planning board meeting in Kenilworth, New Jersey, a CoreWeave representative described converting a former lab building into a data center, with a chiller yard of roughly 50,000 square feet south of the building alongside generator fields.² In Vineland, New Jersey, a phased AI data center’s second amended site plan listed a 178,200-square-foot chiller building on a May 2026 planning board agenda.⁷ After the board approved that phase later in 2026, Blockspace reported that the approved plan included a 92,466-square-foot chiller building, which suggests the design was reduced during review.¹⁵

Those figures are comparable to the data halls they serve, which is why cooling should be in the earliest layout test, alongside the building footprint and lot coverage analysis. If an ordinance counts equipment yards toward impervious cover or lot coverage, a large yard can also affect stormwater sizing.

Direct-to-chip liquid cooling lets facility water run much warmer than in air-cooled halls, which changes the heat rejection mix. ASHRAE’s fifth edition of its thermal guidelines renamed the liquid cooling classes by their upper facility water temperature (W17, W27, W32, W40, W45 and W+) and added W40 because several manufacturers were designing for about 40°C entering water.⁸ At those temperatures, dry coolers can reject heat for most or all of the year without compressors in many climates.

NVIDIA has promoted 45°C coolant that allows heat rejection through outdoor dry coolers instead of evaporative towers, with its engineers suggesting chillers might be needed for perhaps 1% of the year in some climates.¹⁶ That is a vendor claim for a specific design. Schneider Electric’s Steven Carlini has cautioned that a fully chillerless AI facility is not straightforward, because air-cooled support equipment such as networking and power supplies typically represents around 20% of the load and uses a low-temperature chiller.⁹

For site planning, warm-water designs shift space from chillers toward dry coolers, which tend to need more area and fan power for the same heat. A hybrid plant with a smaller chiller fleet for air-cooled loads plus a large dry cooler field is a common outcome. Ask the end user which water temperature class its hardware targets before fixing the yard layout.

Chillers, dry cooler fans and cooling towers run continuously, and new ordinances increasingly treat them as noise-generating equipment. Franklin County, Indiana’s draft data center regulations require chillers, exhaust fans and backup generators to sit at least 500 feet from any property line.⁴ A rule like that can decide where the yard goes and how much of a narrow parcel is usable. Our guide to noise, setbacks and buffers covers sound limits and mitigation.

1. 01Ask the end user for its cooling approach, water temperature class and redundancy level.
2. 02Get unit capacity at the site’s design ambient and the manufacturer’s clearance requirements.³
3. 03Check whether the ordinance sets equipment setbacks, screening or noise limits at the property line.⁴
4. 04Confirm water supply and discharge if cooling towers or adiabatic coolers are planned; see municipal water and sewer capacity.
5. 05Lay out the yard with prevailing winds, walls and screens in mind to limit recirculation.¹²
6. 06Leave room for later phases and for crane and truck access to replace units.

The cooling plant is one of the few systems whose size scales directly with load and whose location is constrained by neighbors, airflow and water at once. BlackForge includes yard space and setback tests in its layout screening; you can get a site reviewed.