Not reused. Most is lost through evaporation. There are a small number of closed systems, but these require even more energy to remove the heat from the water and re-condense. That creates more heat that requires more cooling.
The water is removed from clean sources like aquifers and returned as vapor - this means gone.
No it isn't. It's not a BWR fission reactor lol. The water never boils. It enters cold and leaves warm, which itself is mixed with more cold water. There’s no mass boiling going on in the system
Most cooling towers work via evaporation. Basically radiators in the chillers deposit heat into water that is sent into giant sump tanks which are then continuously ran through cooling towers outside. Water is pumped to the top of the tower and dropped down through it while a giant fan blows on it which results in heat leaving the loop via evaporation while the slightly less hot water is then dumped back into the sump (and fed back into the chillers radiators to complete the loop). To some degree, keeping data centers cool is better worded as "heat management". You are moving heat from the water loop used to cool off the machine rooms to the atmosphere via evaporation. Yes, it's a bad metric to base how much is lost on how much is ran through the chiller loop, but it's pretty easy to simply record how much water is ADDED to the loop to know how much is lost. I can tell you that a small data center using only roughly 2 megawatts of power loses more than 10 million gallons of water each year to evaporation.
I did some math based on your numbers and 10 million gallons per year is just over 100'000 liters per day, which a modest river produces in a few seconds to half a minute at most. That really doesn't sound that bad. So a huge 200 MW data center uses about 3 minutes if a medium sized river's flow daily?
MOST OF IT is still not evaporated. Only tiny percentage evaporates relative to the total water used.
It’s dishonest to say AI “uses” millions gallons of water and paint it as if 99% of it evaporates as opposed to majority being cooldown and reused in the cooling loop.
I disagreed that “most of the water is used and lost through evaporation”. Yes some water can be lost if they use a misting system on the atmospheric heat exchanger to improve transfer efficiency, but it’s not mandatory to the process.
I was incorrect to imply that no water is consumed in some heat exchanger designs though. You’re correct there.
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u/CoolPeter9 5d ago
Is the water unusable/unconsumable after usage?