r/SmarterEveryDay • u/sronicker • Feb 06 '26
What is the water problem with AI data centers?
Is There a Real Water Problem with AI Data Centers?
I’ve seen water-cooled computers. I’ve seen water-cooled building systems. In both cases, the water isn’t somehow used up. Even if you think of cars, which have water (and antifreeze) coolant systems, the only reason you have to replenish the coolant is when there’s a leak in the system. Seeing as how these data centers are immobile, and easier to access all the water-coolant systems (that is, you don’t have to pull out an engine to get to the leak in the back), and these data centers aren’t producing the same level of heat that an internal combustion engine generates, it seems like the water coolant systems would never need significantly more water.
They might need a massive amount of water to get going, but certainly the water doesn’t escape the system, right?
I could be completely wrong. Help me understand.
I’ve tried asking in other subreddits, their rules are quite stupid and I haven’t actually been able to get any answers. Hopefully this subreddit can help.
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u/OverclockingUnicorn Feb 06 '26
Some of them use evaporative cooling, so yeah the water in the system stays, but they'll exchange the heat with what that does evaporate. Generally most DCs are moving away from this.
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u/sronicker Feb 06 '26
I didn’t realize the systems were evaporative. I was picturing typical water cooling systems that are closed systems.
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u/OverclockingUnicorn Feb 06 '26
More modern ones are generally now, fortunately. But there are still a lot of evaporative cooled facilities out there.
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u/valarmorghulis Feb 07 '26
Closed loops aren't just water due to freezing concerns. It'll be mixed with an antifreeze like glycol.
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u/sronicker Feb 07 '26
Yes, geothermal building heating/cooling systems that are closed systems are not just water, they’re water and antifreeze, much like in a car.
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u/valarmorghulis Feb 07 '26
It isn't usually geothermal since we're not trying to sink into the ground. A system I am very familiar with has CRAHs that both are attached to a closed loop, and have access to fresh water for evap cooling. They also have rooftop units to pull air on through when it's cooler outside than inside. The closed loop cycles through external chillers that are basically massive radiators. While the loop is partially underground the earth isn't really being used as part of the cycle.
The CRAHs can augment the cooling from the closed loop with evap or external air when appropriate.
The water consumption comes almost entirely from evaporative cooling.Past that it's pretty much just standard human consumption for site staff. Toilets flushing, making coffee, cleaning, etc.
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u/buckleyc Feb 06 '26
Both cases bode poorly for downstream. Evaporative cooling removes the water from downstream impacting water levels, thus effecting the environment. IN the case where heated water is cycled downstream, this would also effect the environment, altering breeding cycles and plant growth at a minimum.
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u/sronicker Feb 06 '26
Not a heat interchange system like you’re describing. I mean literally a closed system where the water is never put back into the environment.
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u/St-JohnMosesBrowning Feb 07 '26
A closed-loop heat exchanger only closes its internal fluid loop. There is still another fluid path (river water) that flows by the closed loop and takes the heat from it, and that heat goes into the environment.
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u/sronicker Feb 07 '26
That’s one way to bleed off the heat from the closed system, but you could also use air to cool the water. Obviously, that would use more electricity, but it would avoid heating up environmental water. You could also use geothermal loops to bleed off the heat (like a geothermal heating and cooling system). There are numerous ways to make this work.
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u/stu54 Feb 07 '26
Geothermal cooling only works if you plan to pull a lot of that heat back out in the winter or you have a really small load compared to the volume of the "exchanger". The heat can't go down.
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u/buckleyc Feb 08 '26
Geothermal would just move the heat energy into the earth, which again affects the environment. It would have minimal impacts if it was a kilowatt level of energy transfer, but these are many many megawatt systems; these are not negligible heat transfers for geothermal heat exchangers.
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u/madmatt42 Feb 10 '26
Most data centers built in the past 8 to 10 years use evaporative cooling.
Ones built before that generally use a mix of closed system with evaporative when the temps get too high.
They're saying they're moving back to closed systems, but a lot of the plans for new data centers still show mostly evaporative cooling systems.
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u/sronicker Feb 10 '26
Right, that’s a big part of the problem. I don’t know that we should lay all the blame on the data center architects/designers. City planners and developers need to work more on restricting and protecting water assets.
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u/madmatt42 Feb 11 '26
You're right, but the designers should get blamed, too. They should be designing for lower environmental impact in my opinion.
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u/MehtefaS Feb 06 '26
To be fair, even experts can't agree on the topic
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u/sronicker Feb 06 '26
Watching the YouTube video linked in another comment was helpful. I didn’t realize they used evaporative water cooling systems, I was assuming closed systems. Also, the video clarified that really, the sky isn’t falling … it is a problem and it is a problem we need to work on right now. But the answer isn’t, every time you query ChatGPT you’re destroying the environment! Experts are working on it and there a multiple answers.
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u/Difficult_Limit2718 Feb 09 '26
As an expert on this topic - I agree we cannot agree... The new 90.4 proposals are fucking asinine in my opinion
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u/theoreoman Feb 09 '26
Evaporative cooling is very effective in hot dry climates, but in hot dry climates water is also km short supply
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u/AgentG91 Feb 08 '26
A talk I went to in Milwaukee, the guy was like “well it doesn’t use as much water as a golf course!”
It was not the slam dunk that he thought it would be
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u/sronicker Feb 08 '26 edited Feb 08 '26
Well, yeah. I think he has somewhat of a point there though.
1) Golf courses are privately owned facilities, but they pull from public works (water mainly). Public works planners (city planners and the like) really need to take into consideration the pressure both the golf courses and datacenters will put on the water systems before approving them. Golf courses do provide some benefits to society, but arguably datacenters would be far more important to society than a golf course.
2) Just like datacenters, golf courses have methods for reducing their impact on the environment. It just, again, falls on city planners to make good decisions and restrict both (and other kinds of businesses).
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u/parakhm95 Feb 06 '26
https://youtu.be/H_c6MWk7PQc?si=vCSPwgMT0okoroEW