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Comment by alkonaut | Hacker News Reader

I hope no datacenters these days are built on the idea of just running cooling with straight electricity (e.g. no cooling water) and shifting the heat straight out to the air (no waste heat recovery). Even in the late 90's that sounds like a poor design.

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that's how all of Google's datacenters are built in my understanding. Water cooling is very expensive compared to air cooling, and only used for their supercomputer-esque applications like TPU pods. I don't know about waste heat recovery but I don't think they use that either.

"A case in point is our technologically advanced, first-of-its-kind cooling system that uses seawater from the Bay of Finland, which reduces energy use." https://www.google.com/about/datacenters/locations/hamina/

Depending on what you define as water cooling, Google most definitely uses watercooling in all their datacenters.

https://www.datacenterknowledge.com/archives/2012/10/17/how-...

https://arstechnica.com/tech-policy/2012/03/google-flushes-h...

You don't need to water cooled machines, you can use use cold water to chill air.

Heating a community of houses rather than emitting into the air seems like it should be a requirement for building any power hungry industry.

Using the water directly is a lot better for your efficiency, because the computers are quite a bit hotter than the air that cools them so you get higher quality heat from there.

Yes but that requires special gear I assume, that might drive up the cost. Just using cold water for a cheaper heat exchanger (Than some pumped medium) seems like the simple solution if you have unlimited cool water.

There is also immersion cooling. The liquid is not water and it seems is pretty efficient:

https://submer.com/immersion-cooling/

Exceedingly efficient (PUEs of 1.0X) vs cold plate liquid cooled or air cooled. The tradeoff is that mineral oil is annoying (messy especially if leaked but even with maintenance) and fluorinated fluids are bad for the environment (high GWP, tend to evaporate) and crazy expensive. In either case, the fluids tend to have weird effects on plastics or other components, so you have to spend a good amount of time testing your components and ensuring that someone doesn't switch components on your motherboards without you knowing, lest it not play well.

At the low cost of a nitrogen blanket for fire safety, something like n-pentane should be suitable for immersion nucleate boiling cooling with the added benefit of not needing a heart exchanger been the immersion pool and a possible outside air hat rejection condenser.

The solvent effects are relatively well understood for these medium-light alliaphatic hydrocarbons, done care ensure that aren't particularly toxic, and a nitrogen blanket for the rooms takes care of the inherent flammability issue associated with what's basically boiling gasoline on the CPU.

I don't know why you're being downvoted. Something like a third of GHG emissions come from heating, if you can extract the heat from a datacentre you're displacing something like gas, it is something to hope for.

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