Life Support Track: HVAC, Cooling, Water and Power · Module 2 of 4 · about 15 min
Cooling data centers
Data centers turn almost all the electricity they use into heat, and that heat has to go somewhere. The main metric is power usage effectiveness (PUE): total facility energy divided by the energy used by the IT equipment. A PUE of 1.0 would mean no energy goes to cooling or power losses; real sites are higher. DOE's Federal Energy Management Program publishes guidance on improving it.
Most air-cooled rooms use hot aisle and cold aisle layouts. Servers pull cold air in the front and push hot air out the back, so racks face each other front to front. Containment, with doors and panels, keeps hot and cold air from mixing, which wastes energy. Blanking panels in empty rack spaces matter more than people expect.
ASHRAE publishes the temperature and humidity ranges most operators design to; its recommended range for server inlet air is roughly 18 to 27 °C (64 to 81 °F). Running near the top of the range saves cooling energy.
High-density racks for AI training are pushing past what air can handle, so liquid cooling is spreading: cold plates on chips, rear-door heat exchangers and immersion. That brings plumbing, leak detection and water treatment into the server room, which is good news for techs who know both trades.
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Module quiz
5 questions, 4 correct to pass. You'll see what you missed and why, and you can retake it.