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amlutoyesterday at 3:34 PM14 repliesview on HN

This opens up an interesting synergy: district heating. 45C is low but not unworkable for a district heating loop, and a data center might be able to make a nice pitch to a community if the data center offers to provide heat to a district heating system for free. This brings the value to the local community of a nearby datacenter up from near zero to potentially a few million dollars per year.

Summer is still an issue, but fun solutions are possible. With the right geology, I think it’s possible to heat an underground volume in the summer and recapture (some of) that heat in the winter. In many, many climates, annual heating costs are far higher than cooling costs, at least if people aren’t stupid with skylights. [0]

[0] As a back-of-the-envelope heuristic, heating or cooling load due to conduction and air exchange is proportional to the difference between indoor and outdoor temperature. Outdoor temperatures of -10F to 30F are not unusual in the winter and are 40-80F away from an indoor temp of 70F. But outdoor temperatures in these climates rarely exceed 95F and are mostly lower in the summer, so that’s 15-25F of cooling. And heat pumps are more efficient at smaller temperature differences.

Radiative heating is an entirely different story.


Replies

lrasinenyesterday at 4:49 PM

Microsoft's already building data centers hooked up to district heating (Espoo and Kirkkonummi, Finland). Heatpumps are amazing.

(Seasonal heat storage is also a thing, Espoo's neighbours have tens of GWh of storage, with a new 90 GWh cavern in the works. Not sure if the systems are interlinked.)

spockztoday at 7:26 AM

In the Netherlands we are already transporting “waste energy” in the form of heat to greenhouses to warm them in winter.

Also interesting that the article states that this engineering problem hadn’t been solved before. Google pioneered running chips hotter than before. Moreover, we have had water cooling in consumer setups for ages. (At least 30 years.) So what is new is that all chips have been attached to the loop. I couldn’t find what they did with PSU though.

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helsinkiandrewtoday at 10:49 AM

In Finland the datacentre heat is boosted to 60–90°C for district heating (new builds tend to use heat pumps) [1]

A 75-MW data center in Mäntsälä has provided 2/3 of the heat for the town (2,500 homes) for a decade [2]

1. https://www.creatingsustainablecities.org.uk/post/case-study...

2. https://www.sustainabilitymenews.com/waste-management/how-fi...

uberexyesterday at 9:59 PM

45 is the cool temp so they could send the community a higher temp water to their heat exchanger?

Then 45 or below is sent back on the return.

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abc123abc123today at 12:48 PM

Already done and in use in the nordics. Most likely in most dc:s in the northern hemisphere with cold winters.

shagieyesterday at 11:16 PM

Of old... https://web.archive.org/web/20210115152829/https://www.nrel....

It's got a "heat energy to/from campus" exchange in there.

That's a link in March and the air temperature was 31°F.

https://web.archive.org/web/20210708150410/https://www.nrel.... is later with air temperature of 68°F.

guyomestoday at 7:25 AM

The data centers can also be used to heat swimming pools [1].

[1]: https://www.bbc.com/news/technology-64939558

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SkyPunchertoday at 3:26 AM

Heat pumps can effectively bring that temp up higher.

The problem is really how much energy is actually available.

badpunyesterday at 6:42 PM

European cities are doing it already.

normie3000today at 6:16 AM

What's the problem with skylights?

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PunchyHamstertoday at 8:24 AM

> 45C is low but not unworkable for a district heating loop,

*55C is on the output, read article first pls

Main problem is that it wouldn't work with buildings designed for higher heating temperature so it is limited to new builds. And it is not limited just to replacing heaters, hot water system is also designed to work with higher temperatures so heat exchanger used would have to be significantly larger

Another one is that load is not constant on both sides and not exactly something that can be increased on demand (unless you're fine with burning cycles just to electrically heat, but that's massively inefficient)

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ramon156yesterday at 4:01 PM

Do you live near a datacenter? Property value goes down, constant humming.. the way we heat up the earth right now, i don't think you have to worry about heating

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erutoday at 6:59 AM

> This brings the value to the local community of a nearby datacenter up from near zero to potentially a few million dollars per year.

You are not wrong, but the whole issue is a bit silly: there should be legal ways for data centres (and other commercial operations) to just send a few million dollars a year to whichever community they need to convince; instead of having to dress it up as free heating.

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one33seventoday at 6:38 AM

The value of an AI data center in your area is negative, not near zero. Pollution, water use, heat, infrasound (https://www.youtube.com/watch?v=_bP80DEAbuo) and so much more... But at least we may get some cheap heat in the future

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