Something I have been wondering: Why don't data centres use the excess heat for a sort of energy recuperation, turning at least some of it back into electricity?
The degree to which you can extract energy from heat depends on the temperature difference compared to ambient. Efficient power stations all need super heated steam (like 600C). This would be like 100C max which is not very useful for generating electricity. It's fine for heating houses and swimming pools though.
The concept of waste-heat-to-power (WHP) exists, but its efficiency is limited by thermodynamics.
Basically, heat energy is not equal to usable energy. All energy ultimately wants to be heat energy, and it is much easier and more efficient to go from electrical or mechanical energy to heat than vice-versa. Therefore, when you do have an application that actually wants heat, not electricity, such as a public swimming pool or district heating, it is way more efficient to use your waste heat as heat. Even in cases where the desired temperature is wildly different from that of your waste heat, you can convert one heat level into another very efficiently using heat pumps.
Look up Carnot efficiency. The maximum amount of work you can theoretically extract depends only on a temperature difference. For a datacenter running chips at 100C into ambient air at 60F, it's about 25%. So even with perfect capture, you are guaranteed to lose 3/4 of your input energy to the datacenter as heat anyway.
For comparison, an IC engine has a Carnot efficiency of something like 80% on paper, but the reality you get is only 20-30%
Undecided just did an episode on a waste heat machine that is being slowly rolled out to industry.
The founder of the company is also the guy who invented the Super Soaker.
I don't understand how a server (the "washing-machine-sized datacenter") can heat up any fraction of a swimming pool appreciably. Wouldn't it be a few kW tops?
A 30C swimming pool vs a 70C GPU is plenty of temperature difference for a heat exchanger to work with. And even indoor swimming pools have horrific levels of heat loss due to evaporation. But I think the key thing here is that they've undersized the server rack - if its only offsetting 60% of the heating bill, there's a fair margin still being handled by a regular heat pump, which can cycle down in warmer weather.
Pre-GPU times you'd be right, but these days a 4U server could have 8 GPUs pulling 350+ watts each. A washing machine sized unit could contain perhaps 4 of these 4U servers so the unit as a whole could be drawing upwards of 11kW.
This washing machine sized box draws 50kW of power. It wouldn't be able to heat up a cold swimming pool very much, but it would be enough to keep a pool that's already hot at a stable temperature.
All data centers that are in controversial areas should offer free heated swimming pools for the neighborhood. You could add a giant pool complex as a percentage or two of the cost of a big data center.
Surely it's just cheaper to build further away from residential areas? For this to work you'd need to be close to residential areas, but that's where you get the most NIMBY opposition. And if the datacenter is in the middle of some industrial park, who would want to drive 30 minutes to an industrial park to have a swim?
As a kid I have memories of driving a bit out the edge of town to a big steel plant for almost exactly this reason, it's not totally insane.
There's plenty of free parking, free admission, giant pool with some small waterslides and stuff, a bunch of picnic tables and public barbecues, generally some nice greenery and trees for shade, ponds and fountains and stuff, a bandstand, etc.
It's not somewhere you'd pop over to for a "quick swim", but especially for lower income people it's a great place to have around as a "grab a pack of hotdogs and your swim trunks and make a day of it" sort of thing. As a kid we couldn't afford to, say, go to the actual waterslide park or anything so I have a lot of fond memories of visiting the steel plant.
I'm sure the construction and upkeep was less than a rounding error in terms of construction and upkeep costs for the plant itself.
Probably not, at least, I’m pretty sure the heat directly produced by power consumption is minuscule compared to the global warming contribution of the fossil fuels used to produce it, right?
I like to think that the heating, much like their ideal govermental oversight, would have no regulation. I can almost hear the anguished cries of pool goers when a new model gets released and the temperature spikes.
I feel like this is one of those things that sounds good, but it's not. It's probably cheaper to build it far away from residential areas, and it's probably better for the people living there to not live too close to a data center.
why must we tear up undeveloped areas for data centers instead of backfilling vacant industrial areas? Humanity will never rest until all of the world is a brownfield
Personally, I think these data centers should be championing and pushing for district heating and cooling.
Even smaller data centers will be producing enough waste heat to heat 10s of thousands of homes. So why not make residents love you by funding the installation of a district heating system which gives your compute power a symbiotic relationship with the community. Their energy bills go down naturally because your cooling efforts are heating their homes and cooling their homes and you spend less in the winter cooling your servers because that heat is being distributed throughout the community.
It doesn't even have to be free district heating/cooling, just cheaper than using electric or gas heaters.
Equinix AM3 provides heat to the Amsterdam Science Park.
Undisclosed large Swiss private corporate datacenter provides heat to residential complexes in the surrounding area, as well as being integrated with the grid operator and required to spin up generators and island itself on demand, as part of the license to operate.
I have a pool heater and an air conditioner, and I'm running both at the same time. They're fifty feet apart, but this thought crosses my mind constantly.
The sticker on the side of the doohickey in the video really gives the whole thing a feeling of "a dude makes these by hand in his garage." I looked up "AC pool heat exchanger" and lo and behold, the same company showed up as the first result:
I have connected the radiator of my homeserver liquid cooling setup to the heat exchanger of my hot water heat pump. Not sure how efficient it is, but I get a measurable drop in CPU temperatures while the heat pump runs.
Linus Tech Talk (LTT) did a whole series on doing this on the pool at the channel hosts’ house. Extravagant home upgrades are a frequent topic on that YouTube channel… business expense write off yada yada. My general takeaway was, yikes, all that piping and infrastructure would be a nightmare to maintain and will likely just be closed off whenever an issue comes up (or he sells). I’m no expert, but I am a home owner, and have come to form a deep appreciation for maintaining simplicity when it comes to the operation of your house.
Some heat pumps do this. E.g. Panasonic Aquarea EcoFleX. When cooling the house, the domestic hot water tank is used to dump heat into (up to a certain temperature).
You need a lot of heat to do anything useful. I would need to run something like 14 kW of servers to heat my home through winter - that's a couple of hundred thousand in hardware at current prices.
This is mostly just due to how nonprofits work. If you have excess revenue, you can’t return it to shareholders so you might as well spend it on mission-oriented activities.
Keeping in mind that the datacenter operator is also paying the power bill for that (which presumably is roughly 28 kW), amounting to something like £65,000/year at current UK rates
> "Sean Day, who runs the leisure centre, said he had been expecting its energy bills to rise by £100,000 this year.
"The partnership has really helped us reduce the costs of what has been astronomical over the last 12 months - our energy prices and gas prices have gone through the roof," he said.
...
Last summer, BBC News revealed 65 swimming pools had closed since 2019, with rising energy costs cited as a significant reason."
That's terrible that pools are closing. No one even builds new public swimming pools anymore, so it's awful to close the few that exist.
In my home town the local steel plant has been connected to the district heating systems for half a century. This is extremely mature technology and widely used in parts of the world where heating homes is more important than cooling them.
> The data center delivers up to 1.7 MW of reusable heat – enough enough to warm 6,000 energy-efficient homes in winter or provide 20,000 five-minute showers every day in summer.
District heating is a mature technology. Direct Use geothermal heat is the one I am personally most familiar with -- as a geophysicist. However "waste" heat utilization is a definite thing for people with mechanical engineering/heat and mass transfer training.
(Edited to add: there are several examples of public swimming pools being heated with Low T geothermal heat in the Perth metropolitan region of Western Australia.)
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[ 0.27 ms ] story [ 53.2 ms ] threadFor comparison, an IC engine has a Carnot efficiency of something like 80% on paper, but the reality you get is only 20-30%
https://www.youtube.com/watch?v=MuQRxatte5g
Landauer's principle says that even if we could build computers to work at those temperatures, they'd need more power anyway.
[1] https://youtu.be/MuQRxatte5g?is=GUyY4kPH-7WklV1E
https://help.abathhouse.com/hc/en-us/articles/16748674443924...
There's plenty of free parking, free admission, giant pool with some small waterslides and stuff, a bunch of picnic tables and public barbecues, generally some nice greenery and trees for shade, ponds and fountains and stuff, a bandstand, etc.
It's not somewhere you'd pop over to for a "quick swim", but especially for lower income people it's a great place to have around as a "grab a pack of hotdogs and your swim trunks and make a day of it" sort of thing. As a kid we couldn't afford to, say, go to the actual waterslide park or anything so I have a lot of fond memories of visiting the steel plant.
I'm sure the construction and upkeep was less than a rounding error in terms of construction and upkeep costs for the plant itself.
free hot tub
free publicity and good will gathered
("free")
Even smaller data centers will be producing enough waste heat to heat 10s of thousands of homes. So why not make residents love you by funding the installation of a district heating system which gives your compute power a symbiotic relationship with the community. Their energy bills go down naturally because your cooling efforts are heating their homes and cooling their homes and you spend less in the winter cooling your servers because that heat is being distributed throughout the community.
It doesn't even have to be free district heating/cooling, just cheaper than using electric or gas heaters.
Undisclosed large Swiss private corporate datacenter provides heat to residential complexes in the surrounding area, as well as being integrated with the grid operator and required to spin up generators and island itself on demand, as part of the license to operate.
Many such cases!
Air conditioners could do it too, right? Pump heat into a water reservoir instead of just throwing it away?
It's a stainless steel coil that you can put on your A/C and then run water from your pool over it to heat the pool.
https://www.youtube.com/watch?v=J7fB8ul9dZw
https://www.hotspotenergy.com/titanium-pool-heat-exchangers/
Some heat pumps do this. E.g. Panasonic Aquarea EcoFleX. When cooling the house, the domestic hot water tank is used to dump heat into (up to a certain temperature).
(I work there)
You need a lot of heat to do anything useful. I would need to run something like 14 kW of servers to heat my home through winter - that's a couple of hundred thousand in hardware at current prices.
[1] https://www.computerwoche.de/article/2690747/rechenzentrum-h...
[2] https://stefan.schueller.net/posts/kva-winterthur/
https://www.techspot.com/news/97995-data-center-uses-waste-h...
The "data center" produces about 28 kW of heat and the swimming pool has cut its gas bill by 62%. They are saving US$24,000 per year.
- Income: $25.01M
- Expenses: $25M
So "small savings" like this can add up for them.
Keeping in mind that the datacenter operator is also paying the power bill for that (which presumably is roughly 28 kW), amounting to something like £65,000/year at current UK rates
So not even a single rack by modern standards.
You mean server.
"The partnership has really helped us reduce the costs of what has been astronomical over the last 12 months - our energy prices and gas prices have gone through the roof," he said.
...
Last summer, BBC News revealed 65 swimming pools had closed since 2019, with rising energy costs cited as a significant reason."
That's terrible that pools are closing. No one even builds new public swimming pools anymore, so it's awful to close the few that exist.
https://d4project.org/
> The data center delivers up to 1.7 MW of reusable heat – enough enough to warm 6,000 energy-efficient homes in winter or provide 20,000 five-minute showers every day in summer.
https://blog.siemens.com/2026/05/sustainable-data-infomaniak...
https://news.infomaniak.com/en/infomaniak-inaugurates-a-revo...
Paris 2024: Excess Data Center Heat Used to Warm Olympic Swimming Pools
https://www.datacenterknowledge.com/sustainability/paris-202...
(Edited to add: there are several examples of public swimming pools being heated with Low T geothermal heat in the Perth metropolitan region of Western Australia.)