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I've wondered this for a while, why does AI use so much water? Are companies just sending the output of their liquid cooling into the drain? Most computers I've

I've wondered this for a while, why does AI use so much water? Are companies just sending the output of their liquid cooling into the drain? Most computers I've seen use a closed loop and consume no water past the original filling up

istjohn 1y ago
Perhaps they use evaporative cooling towers?
- pc86 1y ago
  In which case it goes right back into the water supply and isn't "used" at all.
- imglorp 1y ago
  Yes - it's going into the air. The water isn't removed from the water cycle, but the problem is that fresh water was removed from the upstream part of the cycle before it could be used by the land. The term is water diversion, where downstream ecosystems, agriculture, and other users are deprived. In an ideal world, all these data centers would instead intake salt water from the ocean, use their energy to evaporate it and condense it, producing fresh water and salts as output.
  - bryanlarsen 1y ago
    There can be very little difference between taking fresh water from a major river that dumps into the ocean vs taking from the ocean. For example, if you took 0.001% of the flow of the St. Lawrence river and run it through an evaporative cooling tower you're doing very little harm and perhaps benefiting the local ecosystem through increased rainfall. If you took 50% of the flow it'd be a problem, but the St. Lawrence is massive. People think water is scarce, but there are still parts of the world where water is abundant, where flooding is more of a concern than fresh water scarcity. Combine with Quebec's cheap electricity, and it seems an ideal place to site data centers.
gwill 1y ago
at scale, data centers use cooling towers with fresh water, not a closed loop liquid cooling system. https://oecd.ai/en/wonk/how-much-water-does-ai-consume https://oecd.ai/en/wonk/how-much-water-does-ai-consume
OtherShrezzing 1y ago
There are closed-loop datacenters, but the hyperscalers now use evaporation chimneys. Google used ~21bn litres of water in 2023-24.
- voidUpdate 1y ago
  Doesn't that fall back down again as fresh rainwater?
  - eesmith 1y ago
    Sure. While lowering the recharge rate on the aquifer, the river flow, etc. Instead of being re-used downstream, it's re-used downwind. Snow melt original destined for the over-allocated Colorado might instead end up in the Mississippi. All that irrigation water pumped out of the ground in the southwest falls back as rain too. While the land subsides, plants can no longer reach water, and towns have to build deeper wells.
h4kor 1y ago
> Are companies just sending the output of their liquid cooling into the drain? basically yes. Closed loop systems require more energy and are more expensive investments. The main concern for data centers is Total Energy / Energy Compute. There was a good talk about this at 37C3 https://media.ccc.de/v/37c3-11796-energy_consumption_of_datacenters https://media.ccc.de/v/37c3-11796-energy_consumption_of_data...

istjohn 1y ago

Perhaps they use evaporative cooling towers?

pc86 1y ago
In which case it goes right back into the water supply and isn't "used" at all.
imglorp 1y ago
Yes - it's going into the air. The water isn't removed from the water cycle, but the problem is that fresh water was removed from the upstream part of the cycle before it could be used by the land. The term is water diversion, where downstream ecosystems, agriculture, and other users are deprived. In an ideal world, all these data centers would instead intake salt water from the ocean, use their energy to evaporate it and condense it, producing fresh water and salts as output.
- bryanlarsen 1y ago
  There can be very little difference between taking fresh water from a major river that dumps into the ocean vs taking from the ocean. For example, if you took 0.001% of the flow of the St. Lawrence river and run it through an evaporative cooling tower you're doing very little harm and perhaps benefiting the local ecosystem through increased rainfall. If you took 50% of the flow it'd be a problem, but the St. Lawrence is massive. People think water is scarce, but there are still parts of the world where water is abundant, where flooding is more of a concern than fresh water scarcity. Combine with Quebec's cheap electricity, and it seems an ideal place to site data centers.

gwill 1y ago

at scale, data centers use cooling towers with fresh water, not a closed loop liquid cooling system. https://oecd.ai/en/wonk/how-much-water-does-ai-consume https://oecd.ai/en/wonk/how-much-water-does-ai-consume

OtherShrezzing 1y ago

There are closed-loop datacenters, but the hyperscalers now use evaporation chimneys. Google used ~21bn litres of water in 2023-24.

voidUpdate 1y ago
Doesn't that fall back down again as fresh rainwater?
- eesmith 1y ago
  Sure. While lowering the recharge rate on the aquifer, the river flow, etc. Instead of being re-used downstream, it's re-used downwind. Snow melt original destined for the over-allocated Colorado might instead end up in the Mississippi. All that irrigation water pumped out of the ground in the southwest falls back as rain too. While the land subsides, plants can no longer reach water, and towns have to build deeper wells.

h4kor 1y ago

> Are companies just sending the output of their liquid cooling into the drain? basically yes. Closed loop systems require more energy and are more expensive investments. The main concern for data centers is Total Energy / Energy Compute. There was a good talk about this at 37C3 https://media.ccc.de/v/37c3-11796-energy_consumption_of_datacenters https://media.ccc.de/v/37c3-11796-energy_consumption_of_data...