3d ago

How do AI data centers manage to consume water, but when I cool my house, my A/C makes water?

Apparently data centers routinely burn through water at a rate of about 1.9 liters per KWh of energy spent computing. Yet I can 🎮 HARDCORE GAME 🎮 on my hundreds-of-watts GPU for several hours, without pouring any of my Mountain Dew into the computer? Even if the PC is water cooled, the water cooling water stays in the computer, except for exceptional circumstances.

Meanwhile, water comes out of my A/C unit and makes the ground around it all muddy.

How am I running circles around the water efficiency of a huge AI data center, with an overall negative water consumption?

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It's used like sweating. We lose heat by havibg water evaporate off our skin. Right now get warm water and put it on your arm, then blow on it. It gets cold until it is fully evaporated. For water to change from the liquid to the gaseeous phase it needs energy. Think like water molecules are holding hands in a liquid. If one of them wants to come free and fly through the air it needs to somehow get the energy to break free from the grip of the others first. When water evaporates from your arm it tales this energy in the form of heat. It turns heat and uses it to get to the gaseous phase. As long as there is water on your arm it can be cooled that way.
That's what data centers do as well. They take water to cool their processors and the let part of it evaporate into the air. That way the parts of the water that remain are like your arm - the get cool quickly.
It's very effective. But if you live in a small town and next door there's a massive datacenter that takes out all the groundwater and basically just boils it until it disappears, you might get angry after a while.
- I once read of a data company that had their servers pretty far north and that it was cheaper to send people there to control it than it was to cool it. Basically used a ventilation system that took the outside air
The simply answer is that your A/C dumps heat outside using big metal fins, it's not terribly great, but it works well at that scale.
Dissipating it into the air for the amount of heat some data centers need to get rid of doesn't cut it, so they use evaporative coolers.
The phase change of evaporating water from liquid to gas uses approximately 7x more heat energy than taking room temperature water and getting it up the boiling point itself.
Essentially they stick their large metal fins from the AC into a large pool of water and boil it off. This gets rid of the energy with a much smaller and cheaper system, but uses up water.
Edit: To clarify on the water in your home AC, the water is actually being collected INSIDE on the chilling unit as lowering the temperature decreases the ability for the air to hold water, it's then being pumped outside. Data centers recirculate most of their air, letting in only a small amount of fresh air that they pre-chill, rather than letting fresh air in from the outside all the time like your home does.
- Home hvac units don’t let in fresh air all of the time, they recycle air.
  
  The HVAC system no, the home itself, yes.
  Depending on how old your home is of course, newer homes tend to have lower exchange rates.
  Also datacenters don't have windows, or even doors constantly letting people in and out of cooled areas and outside.
  
  My HVAC system has an inside and outside air source.
They use evaporative cooling for a chiller plant most likely.
- Why would they design around evaporative cooling when water consumption is a problem?
  
  Because evaporative cooling is much cheaper and easier to accomplish at scale, and megacorps don't care about long-term resource constraints until it begins to affect their wallets.
  
  Because it's cheap and easy.
  
  Because they are assholes who hate the environment. The same reason they are using fossil fuels to power their slop centers instead of renewables.
  
  most effective form of heat transfer
  
  Because line must go up
  
  it wasn't a problem before they started doing this
What I don't get is how the water is "consumed", it's not like it's gone right? It evaporates and then just comes back down as rain surely?
Same with water consumption of a sweater or a steak.
There probably is some good reason for measuring it like that but conceptually I don't get it.
- Even though there is loads and loads of water on the planet, the amount of fresh/drinkable/usable/accessible water is tiny. This water evaporates and rains back down, but this will most likely fall over the ocean, or on land and go into the ground, or into some other unusable area/form.
  Water suitable for human use is a scarce commodity and needs to be preserved. Of all the water lost to the atmosphere from server cooling systems, almost none of it can be recaptured again.
  
  Why are they not using a closed loop system with condensers collecting the evaporated water?
  
  Hadley cells bring them inland does it not where it condenses and rains flowing back towards the ocean where it again evaporates and travels inland rains and goes back to the ocean.
- Just cause you use water in one place doesn't mean it'll come back in the same place.
  
  It does though doesn't it
- This is the complicated part with water consumption, saving water in the Netherlands won't make rain in Morroco.
  However, there is only so many rain water stored in the ground at a given time and brought by the rivers. This water need to be used mostly for agriculture, then human consumption, and finally industry. Once it's back in the cloud we don't fully know where it will fall again, let alone if it's polluted.
  Sure it's a renewable ressource, the problem start when you the water faster than the rate at which it renews, especially during summer. In Europe the problem will be even worse with the global warming. The alpine glacier are disappearing meaning that we'll loose a major water reserve for summer
- Most people are not directly collecting rain to drink.
  
  Yea we are
Server farms use water to cool computers, it's like water called computers but on a bigger scale
Aircons condense water from the atmosphere the same way water on your shower mirror happens because the mirror is colder than the fog
If you're familiar with condensation and the rain cycle it should help you understand further
To add to what others said, it’s a tradeoff.
Your gaming PC not only runs up your electric bill from the wall, but the AC as well. It has to work to get all that heat out.
This is the equivalent of water cooling your PC, and piping it to a hot tub outside. It would heat it and evaporate water faster, but it’s basically free and uses basically no electricity.
That’s the tradeoff. It’s water evaporation instead of heat pumps. It’s trading water usage for lots of electricity usage, which in some cases, is well worth it.
And what if you live in a cold climate, you say? Well, evaporative cooling is most cost efficient in hot and (ironically) dry climates.
taps the fact that electricity is a steam reaction and even if you don't see it, the electricity you're using is made by decompressing water into vapor, whether by burning coal through turbines/boiled wind from water sources creating wind power/ even nuclear reactors are often a boiling water reaction going through turbines, creating a net loss of 'water' if we don't have natural condensation utilities to convert 'air'
- that water usually goes through a heat exchanger in a closed loop. there's a reason most power plants are built by lakes.
  also, explain "boiled wind"?
  
  If it's truly a closed loop, why do you need a lake, a true closed loop has zero need for local water sources, else there's some sort of negative that they're compensating for which, in case of local water sources, there's not enough infrastructure if any of that water OR HEAT leaves the system faster than it enters
  
  Water exchange above large bodies of water causes thermal dynamic exchanges deliberating speeds of wind currents
- The water is for sure going up there with help, it won't come back down without help in equal measure, it's dynamics are completely spun out
Water is evaporated which takes a lot of energy due to latent heat. Essentially its very energy expensive to boil water.
At this point, I wouldn't be surprised if it turned out that they're destroying the environment on purpose for some nefarious purpose. e.g. maybe they think it's easier to rule the masses if natural ressources are very scarce.
- I think it's more likely that yellow journalism is making an issue out of something that isn't as big a deal as it is.
  
  Since when does yellow journalism care about the environment?

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