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Comment by geophertz | Hacker News Reader

The thing is that if putting data centers underwater solves the cooling problem, all the heat produced is wasted, so it this really a good solution?

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Heat is awfully hard to transfer in the first place, especially when it's not even that hot. It's handy if you can put your data center underneath a swimming pool, for example. But I'm not aware of any large-scale heat recovery projects from data centers. Data centers generally spend extra energy to remove the heat...

But honestly who cares if your power comes from renewables in the first place -- solar and wind? It doesn't seem right to even frame it as "wasting" heat in the first place, anymore than the sun's heat was being "wasted" warming up the ocean in the first place.

The new LUMI EU supercomputer in Finland will put its waste heat into a district heating system: https://www.hpcwire.com/off-the-wire/csc-lumi-supercomputer-...

I'm sure smaller scale data centre heat to district heating schemes must already be in place. Fundamentally you are using the same technology to cool the data centre (a heat pump), just pushing that heat into hot-water / steam, rather than dumping into the air.

This has been active in Stockholm for years, at least:

https://www.opendistrictheating.com/

Also Wedos here in Czech republic; https://www.wedos.org/en/

It's a bit hard when the temperature deltas are so small, though. It probably works well if you're pre-heating air before the main heat source in a very cold region, but otherwise you'd need to use some sort of heat pump to get it to move around.

There are towns in Denmark getting heat from Google and Facebook datacenters so I don't see why it shouldn't work elsewhere. The way MS does it here the heat is 100% waste and should be taxed like other waste. Not to mention what about the noise? The sea is already noise polluted.

Here's a source (in Danish). Wind energy in -> 25 MW/h of heat out (to heat up 12.000 houses):

https://www.computerworld.dk/art/252732/facebook-vores-data-...

You want to tax unused heat? Are you serious?

If entropy continues to be an issue taxation and regulations are sensible solutions.

If the power is generated from waves, wouldn't the energy would have gone to waste at the shoreline/breaker anyways?

> I'm not aware of any large-scale heat recovery projects from data centers.

I don't know what you'd call large-scale, but the school I went to was entirely heated by the datacenter across the road and the DC still had plenty of heat to spare. Afaik they heat all of Science Park Amsterdam with the Equinix DC just to the east: https://osm.org/go/0E6VOVkQc-. I think it was a requirement of the local government that this waste product be reused. Amsterdam has also had a datacenter stop due to power supply issues.

Edit: this seems to be the press release (only source I could find): https://www.equinix.com/newsroom/press-releases/pr/122801/eq... "Third data center in amsterdam" matches that this DC is called Equinix AM3, and it says "Excess heat from the data center will be used to warm nearby buildings and for other third-party uses."

Not to say that this happens with all the data centers across the world, but if using a decent chunk of a DC's waste heat isn't a large-scale heat recovery project, then I'm not sure what would be.

Well, you could put a sterling engine to transfer the heat to the ocean and generate energy back. This is exactly what some submarines do [1]

[1] https://en.wikipedia.org/wiki/Applications_of_the_Stirling_e...

I don't know if it's the best solution, but it would seem to beat the "use A/C to cool it" solution.

The heat produced in a traditional data center is already unwanted and wasted and takes a ton of electricity and machinery to get rid of. Given that processors like to operate around 50 C, that's not a lot of heat to preserve and transport and do something useful with.

Maybe design electronics that are happy at higher temperatures?

The issue is more that transistors will always generate some heat- making the threshold higher / being more efficient doesn't solve the fact that there's still some waste thermal energy that needs to be removed.

Modern transistors are rather small and would desintegrate at too high temperatures. Not much you can do about it at those scales, any material will decompose.

It's literally waste heat, what else are you going to use it for? You won't efficiently generate electricity with it or anything like that. About the best you could hope for is warming up inhabited spaces in winter, but that ends up not being cost-effective because you'd rather have the data centers in the middle of nowhere where land is cheap (and you can't really transport the heat to where it's actually needed).

That's the cruel part of the thermodynamics. The waste heat here is not hot enough so it's really difficult for the recovery effort to reach a reasonable efficiency economically.

That's why you don't see it...

https://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodyna...

Sure you see it. This is just a way to try to get rid of waste for free. Both Google and Facebook (Apple too I believe) delivers heated water to heat up houses from their datacenters. The one near me (Facebook) takes in wind energy and produces 25MW an hour and heats up 12.000 houses by wind energy and waste heat.

It isn't wasted it is helping to heat up the oceans.

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