Liquid cooling in data centers: what it changes for a site

What liquid cooling is

Liquid cooling is a way to remove heat from computer equipment with a fluid instead of moving air alone. The fluid carries heat away from the chip, the rack, or the whole server. Liquid holds and moves far more heat than the same volume of air, so it can cool equipment that air cannot.

How liquid cooling works

Liquid cooling works by pumping coolant close to the source of heat, then to equipment that sends the heat outside. Designs fall into three broad groups.

• Direct-to-chip cooling. Cold plates sit on the processors, and coolant flows through them in a sealed loop.
• Rack-level cooling. Coolant runs to a heat exchanger in the rack door or beside the rack, which cools the air around the servers.
• Immersion cooling. Servers sit in tanks of a fluid that does not conduct electricity, and the fluid carries the heat away.

Why dense computing pushes toward liquid

Dense computing pushes toward liquid because air runs out of room to carry the heat. Racks built for artificial intelligence and other heavy workloads pack more processors into the same space, and each processor draws more power. Nearly all of that power becomes heat. Past a certain density, fans and cold air cannot remove the heat fast enough, and liquid becomes the practical choice. See data center power requirements.

Where the heat goes after the rack

After the rack, the heat goes to outdoor equipment and leaves the building. Liquid cooling changes how heat moves inside, not whether it has to go outside. The coolant loop hands its heat to a second system, and that system sends it to the outdoor air. Common choices include:

• Dry coolers. Fans blow outdoor air across coils that carry the warm fluid. They use little water, draw more electricity, and need yard space.
• Cooling towers. Water evaporates to carry the heat away. They use more water and less electricity.
• Hybrid units. These run dry most of the year and add water in peak heat.

The choice between water and electricity belongs to the buyer’s mechanical engineer. See data center water usage.

What liquid cooling changes for a site

Liquid cooling changes what a site must supply and where outdoor equipment sits. The effects fall on water, space, power, and neighbors.

Water. A design that rejects heat through cooling towers needs a water provider that can supply the makeup water and a sewer system that can take the discharge. A design built around dry coolers needs far less water.

Space. Dry coolers and chillers take up yard area outside the building. That ground comes out of the tract’s usable acres.

Power. Dry heat rejection draws more electricity on hot days, which adds to the load the utility must serve.

Sound. Outdoor fans run day and night, and their placement matters near homes. See data center noise.

What the public record shows

The public record shows where water and sewer lines run, the zoning and setback rules, and the shape and size of a tract. It cannot show which cooling design a buyer will choose, how much water that design needs, or whether the provider will serve it. We read what the record holds and mark the rest as questions.

Who confirms it

The buyer’s mechanical engineer chooses the cooling design. The water and sewer provider confirms supply and discharge terms. The serving utility confirms the power load. The county or town confirms setback and noise rules.

For how the other designs compare, see data center cooling systems.

Questions

Does liquid cooling use less water?

It can, but the answer depends on the equipment outside. A liquid loop that feeds dry coolers uses little water. A loop that feeds cooling towers still loses water to evaporation.

What is immersion cooling?

Immersion cooling places servers in tanks of a fluid that does not conduct electricity. The fluid absorbs heat directly from the components and carries it to a heat exchanger.

Does a landowner need to know which cooling a buyer will use?

No. The owner needs to know what the site can supply: water, sewer, power, and room for outdoor equipment. The buyer’s engineer fits the design to those facts.