How a data center keeps servers cool

Server racks face each other across a cold aisle where chilled air rises from perforated floor tiles. Fans pull that air through the servers and blow it out the back into hot aisles, and cooling units pull the hot air back, cool it and push it under the floor again. Power Usage Effectiveness (PUE) compares the whole building's power with the power the computers themselves use, so better cooling means a PUE closer to 1.

Controls

Labels

Animation speed

IT load (servers)

Cooling efficiency (COP)

Heat removed per unit of electricity used by the cooling system.

Cold aisle containment

Step through it

Cold air under the floorCooling units blow chilled air into the space beneath a raised floor. Perforated tiles let it rise only where it is needed, in the cold aisle.
Through the serversRacks face the cold aisle. Server fans pull cool air in the front and push it out the back, picking up the heat from chips and power supplies.
Back to the cooling unitHot exhaust rises from the hot aisles and returns to the cooling units, where coils carrying chilled water or refrigerant take the heat out.
Stop the mixingWithout a barrier, hot exhaust curls over the racks and mixes with cold supply air. A containment roof keeps the streams apart so the cooling system can work less.
Reading PUEA PUE of 2 means half the power goes to cooling and overhead. Efficient cooling pushes the number toward 1.2 or lower.

What PUE measures

PUE = total facility power / IT equipment power. Total power includes servers, cooling, lighting and losses in power conversion. A perfect facility would score exactly 1.0.

This teaching model computes cooling power as IT load divided by the cooling system's coefficient of performance (COP), adds a flat 8 percent of IT load for lighting and power conversion losses, and assumes containment cuts cooling power by 20 percent. Real savings depend on the building.

Try it: start at COP 3 without containment and note the PUE of about 1.41. Turn on containment, then raise COP to 7. The PUE drops toward 1.2 and hundreds of megawatt hours of overhead disappear each year.

Why it matters

Data centers use a measurable share of U.S. electricity, and AI computing is growing that share. Every bit of cooling overhead is paid for 8,760 hours a year, so hot and cold aisle layout, warmer supply temperatures and free cooling with outside air pay off quickly.

Where Avid uses this

Avid's founder began his career as an HVAC apprentice at 16, and the same airflow and heat removal principles behind building HVAC run every data center.

Sources

Best Practices Guide for Energy-Efficient Data Center Design (NREL, revised 2024)U.S. DOE Office of Scientific and Technical Information
A Critical Analysis of Power Usage Effectiveness and Its Use as Data Center Energy Sustainability Metrics (CIFE WP131)Stanford University
Data Center Energy EfficiencyU.S. Department of Energy, FEMP

How to cite this model

Avid Solutions International. (2026, November 11). How a data center keeps servers cool [Interactive 3D model]. Avid Field Lab. https://avidsolutionsintl.com/explore/data-center-cooling

Last updated November 11, 2026

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