Google's Liquid Cooling

I have encountered a lot of references to AI using water, but with scant details. Is it using water in the same way a car uses a road? The road remains largely unchanged?

The implication is clear that it is a waste, but I feel like if they had the data so support that, it wouldn't be left for the reader to infer.

I can see two models where you could say water is consumed. Either talking about drinkable water rendered undrinkable, or turning water into something else where it is not practically recaptured. Tuning it into steam, sequestering it in some sludge etc.

Are these things happening? If it is happening, is it bad? Why?

I'd love to see answers on this, because I have seen the figures used like a kudgel without specifying what the numbers actually refer to. It's frustrating as hell.

The water is "used" in the sense that it evaporates. At a global average rate of 1 liter per kilowatt-hour of energy, Google claims.

This article will help you. https://www.construction-physics.com/p/how-does-the-us-use-w...

> ...actual water consumed by data centers is around 66 million gallons per day. By 2028, that’s estimated to rise by two to four times. This is a large amount of water when compared to the amount of water homes use, but it's not particularly large when compared to other large-scale industrial uses. 66 million gallons per day is about 6% of the water used by US golf courses, and it's about 3% of the water used to grow cotton in 2023.

> I have encountered a lot of references to AI using water, but with scant details.

Here you go: https://en.m.wikipedia.org/wiki/Cooling_tower

Data centers use evaporative cooling towers which evaporate water to reject heat to the atmosphere.

Does this evaporated water stay in the loop and condense out later? Is an extra liter on the front end needed in the line until the first liter falls out of the back end?

What does that mean for environmental impact? Hydroelectric power uses water in the sense that the "used" water is at a lower altitude. What happens once that is done, is what matters.

Depending on what global average means, it seems like that's quite a lot of cycling of evaporation unless they are releasing steam at 800C

Looking up overall water usage, the US uses 27.4Billion gallons a day residential and 18.2 Billion gallons industrial. It surprised me that industrial was lower, but I guess the US manufactures less these days.

If the 1kwh per litre were accurate then judging by this calc https://www.google.com/search?q=(27.4billion+gallons+*365)*+... 37 857 903.3 terawatt hours

0.1% of The residential water use of the US would be enough to cool the entire Electicity output of the world (about 30,000TWh)

(of course, with these things it's easy to slip an order of magnitude(or several) so best check my numbers)

It means different things in different places, depending on where the water was sourced and the counterfactual of what would otherwise have happened to it. For example if you source surface water that evaporates, and the local rainshed feeds that watershed, then it's virtually closed-loop. If you're pumping fossil water out of an aquifer, and it rains over the ocean, then it's the opposite.

I suppose in some desert-ish climate the extra moisture given to the air doesn't rain down nearby but moves with the wind somewhere far away where it rains. So there might be an effect of using locally precious water even if it's a closed loop on a continent level.

My understanding is that most new data centers don't use evaporation cooling these days, at least in water-sensitive areas. Hard to find solid data on this either way, though.

Of course, if you're using dry cooling, it uses more electricity, so hopefully you're using solar, not a source that uses evaporative cooling to produce electricity (if in a dry climate).