There is basically zero truth about the water use propaganda. Liquid cooling is closed-cycle, just like in a car.

wlesieutre 6 hours ago | parent | next [-]

Having a closed coolant loop and using evaporative cooling which expends water aren't mutually exclusive. It's possible for a datacenter to manage heat rejection by blowing air over a radiator like a car does, but it's much easier and cheaper to cool by evaporating water.

This can be set up using a closed coolant loop that takes heat out of the servers, then cools back down the coolant by exchanging that heat into a second separate coolant stream. That way you don't need to care as much about the purity of the water you're drawing and evaporating for evaporative cooling, only the first sealed loop gets pumped though your server racks.

This is the type of setup they're talking about with the much discussed xAI datacenter in Memphis, where xAI pinky swears they are definitely going to resume construction on their wastewater treatment plant [1] and use that for cooling instead. It definitely is designed to consume water and evaporate it, not a closed system like a car radiator that puts its waste heat into ≠the air with no evaporation.

[1] https://wreg.com/news/local/xai-to-resume-construction-on-wa...

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bri3d 6 hours ago | parent | prev | next [-]

A sizable percentage of datacenters use open loop water spray towers, but the alternative, forced air exchange (ie add more giant fans) uses more electricity. It’s fairly complex to quantify which is “better” or “worse” but there exist data centers that evaporate a ton of water and send it elsewhere. (for what it’s worth I agree most of the anti datacenter hype is overblown and driven by specific poorly designed gas turbine powered installations).

	▲	magicalist 6 hours ago \| parent [-]
		> driven by specific poorly designed gas turbine powered installations *increasingly nonspecific. See [1] for example [1] https://floodlightnews.org/ai-data-centers-texas-pollution-l...

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nullpoint420 6 hours ago | parent | prev | next [-]

I thought this too. Apparently there’s open cooling systems as well that are more efficient

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thedougd 6 hours ago | parent [-]

Yes. Evaporative cooling towers. I suppose in those cases nearly all the water used goes to atmosphere.

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userbinator 5 hours ago | parent [-]

...which then comes down again as rain, and in those areas where it's dry enough that evaporative cooling works, the increased humidity might actually be a good thing.

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altcognito 5 hours ago | parent [-]

In areas it's dry enough it is just leaving that watershed. It will be carried hundreds and thousands of miles away.

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userbinator 4 hours ago | parent [-]

Decades ago, there was a plan to equalise the water supply throughout the country: https://en.wikipedia.org/wiki/North_American_Water_and_Power...

Now China is beating us: https://en.wikipedia.org/wiki/South–North_Water_Transfer_Pro...

	▲	altcognito 4 hours ago \| parent [-]
		Oh good, I'm glad China is beating us in the path to stupidity. These types of projects are the dumbest things we ever did here. Classic! Nothing dumber than reallocating resources thouands of miles away from where they should be.

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uluyol 6 hours ago | parent | prev | next [-]

The water use comes from evaporative cooling, not liquid cooling.

Liquid cooling pulls heat away from the chips. Evaporative cooling takes it out of the building.

There are alternatives, but evaporative cooling is very energy efficient.

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isuckatcoding 6 hours ago | parent | prev [-]

Is this actually true?

Aren’t there real instances of metas data centers causing havoc for nearby residents? Light/boise pollution, contaminated water are real things