Hacker News Reader

Comment by LaurensBER | Hacker News Reader

While it seems reasonable to comment about how we're using water it also seems like a complex topic.

What happens to the (slightly warmer) water after it has been used? Is there a way we could return it in a way to minimise impact? I.e if we extract ground water should we inject it back into the ground? Would that even matter?

In the end I have a feeling that the most efficient solution will most likely be to just increase the price of water during a drought. People will complain but it won't be long before the big consumers will happily adjust their consumption or move to an area with abundant water.

View on HN

I've been wondering this too (what happens to the warmer water), and haven't found a satisfying or objective explanation. Everything is "AI drinking my water" which... just makes no sense.

Systems with open-loop evaporative cooling towers lose water to evaporation.

Probably a redundant comment, but it's the evaporation, i.e. conversion of water from liquid to gaseous form, that provides the cooling effect. At that point it's gone.

Using water to cool a data center is absolutely not equivalent to using it for farming. Once you irrigate a field, that water is gone. But if water is cooling something, then it can be collected and used again. Of course, that requires a city or county to have a water reclamation program.

Likewise, if you water a lawn, that water is gone. But if you flush water down a toilet or a shower drain, the water is potentially reusable. Just needs to be cleaned.

Waste water can also be used for cooling. I believe that's how the Palo Verde nuclear plant outside of Phoenix is cooled.

"it can be collected" is far different from "is collected".

If the data center uses evaporative cooling then most of the water vapor leaves that water basin. While some of that irrigation water goes into the ground and stays in the water basin for a longer time.

Likewise, if you water a lawn - and assuming you are not so daft as to do it when the sun is high - the most of the water will go into the ground, reaching eventually the acquifer or a waterway, for eventual downstream reuse.

This is why cities in dry climates, or places facing a drought, will have restrictions like "No outdoor watering between 10 a.m. and 6 p.m."

> Once you irrigate a field, that water is gone.

This doesn't seem true to me, in the sense that anything is truly "gone". The water doesn't cease to exist or is converted to anything other than water. It just moves.

Right. The water isn't gone from the universe, certainly. But it's gone from the city/county water system. You've then got to wait for it to come back via the natural water cycle. Whereas it's a lot more efficient to keep as much water as possible in the human system and just keep cleaning and reusing it.

Lawn & Grass Watering consume roughly 8 to 11 times the volume consumed by AI servers globally, so we can reduce Lawn by 10%

Reply on news.ycombinator.com