Wish this kind of joined up thinking happened in places other than the Nordics.
Data centres and industry exist and dump heat all over the world. Putting it to use is a no brainer.
this post was submitted on 21 Dec 2023
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I think the Nordics is probably the only place capable of utilizing this system in the first place. It looks like they have a utility system that already centralizes heating for their communities. They basically have a hot water line that circulates through radiators located in all the buildings in the community. Facebook was able to hook their heat exchange to this system, so they didn't have to build any real infrastructure.
I'm not really sure how efficient this solution is, it really depends if their centralized system is a closed or open system. The water Facebook is pumping out is only 80 degrees, and has to be heated up to 170 by the utility company for service.
The problem is that while these servers produce a large volume of heated air, the intensity of that heat is very low, making it hard to exploit or preserve for transfer.
Germany has this concept implemented in a lot of places, too.
Ironically this results in some problems now. For example the city Salzgitter (100k inhabitants) is heated by the local steel plant – which currently transitions towards green steel. Their transition also leads to a shut down of their blast furnaces, leaving the inhabitants of Salzgitter out of heating.
No idea what their plan is to replace it, though.
District heating in Denmark is a closed system. The heated water leaves the Combined Heat & Power plant (CHP) or an industry's heat pump and runs towards the consumers. In radiators it flows through and you pay for the difference in heat in/out and for tap water/shower etc. you have a heat exchanger that heats up the normal cold water line. The now colder heated water then runs back to the CHPs where it gets reheated.
Denmark may be big on windmills but CHPs are actually another energy technology that's widespread here.
Ahh, that's what I was hoping for! I was afraid it might be an open system, making the additional heat exchange from the servers mainly a vanity/pr project.... My expectations for sensible utility companies have been damaged by living in America.
But yeah, depending on how much heat has been dissipated by the end of its loop, utilizing the heat from the servers right before it gets to chp would significantly reduce the amount of energy needed to get the temp up to 170f.
I wish we could do something similar, but I guess it would be stealing someone's freedom or something?
I think you get a surcharge if your out heat is too high, meaning your radiators are running so high that you aren't utilising the heat effectively, so the end-of-loop water should be pretty cold. Another thing to keep in mind is that CHPs would still generate the waste heat from producing power, so it's a pretty efficient loop.
Fun fact, the Facebook district heating project was actually a big talking point due to server farms producing much lower heat than what is needed in district heating. People were split on whether it would actually have enough of an impact. As an example, my heat comes partly from a cement factory, a waste incinerator and a CHP as well as minor oil-based emergency heat generators. The CHP is capable of producing all heat by itself and the cement factory and waste incinerator were enough when the CHP had a major breakdown last year during autumn. During winter oil-based heat generators might be turned on to supplement the network on very cold days but they're expensive to run, so they are only used a couple of days a year.
Other places don't have central heating? Damn, I've always taken it for granted
Russia is another one big on central heating. I had to go there for work many times way before the war and their system was a nightmare. I was afraid I was going to freeze my ass off being in late-winter Moscow and instead, it was too hot everywhere. In the office they had to get a portable AC and in the house I stayed I turned down all the radiators in the room I slept and still had to sleep with the window slightly open.
Let's just say I'm definitely not some Nordic person, quite the opposite but their system was whacked.
You see, their system could be heaven (it's the same here). But we opt out for the lowest
Here the saying is, you feel cold, warm up. Not something Yanks take nicely haha
I think it could work for some college campuses too? I know there are a lot that use (used?) centralized steam heating and have a lot of that infastructure to pump the steam around still in place
Yeah this is the sort of problem solving we'll really need moving forward
And if even Meta agrees to do it, there's no excuse left, is there
They did it in a place that most both subsidized and forced Meta to do it. Don't expect them to do it anywhere else.
District climate relies on density, so it really only works in cities.
This is actually a law in Denmark, so it's something Facebook had to do.
Any new data centers build on Danish ground need to be hooked up to the central heating system, providing heat to the community.
Perfect use of resources.
"Perfect use of resources" might be overstating it a bit.
They took a waste product and used it to heat homes, sounds responsible and efficient.
Actually, the whole of Facebook shutting down and removing Zuckerberg would be better use of resources.
With my growing homelab, I’m nearly self hosting this same sort of solution in my basement.
It's all fun and games until you get raided by some very disappointed DEA agents.
That's okay. They found a roach in the basement so you're going away for 3-5... Mission accomplished!
If you live in an environment that gets hot in the summer time you may think about getting a heat pump for your home. That much heat energy being generated in the summer would be great for your energy bill. Instead of battling the heat generated by your lab with AC it would actually be used to create a more efficient heat energy exchange for the pump.
Can you elaborate on how creating heat in summer time helps save money on cooling your home?
Heat pumps are great, but what this guy is saying is wrong. Generating heat in the thing you're trying to cool won't help save any money no matter the technology.
Let's say you were deliberately trying to heat something and cool something else, like a water heater and your home. Then heat pumps are doubly effective. Maybe that's where the confusion in this comment stems from, but that's not what's going on with a data center.
Generating heat in the thing you're trying to cool won't help save any money no matter the technology.
I should have been more specific, the savings would be from compartmentalizing the hot room from the rest of the HVAC system.
If you partition the lab from the rest of the hvac system and install a heat pump for the lab, it would drastically reduce the amount of heated air the HVAC system has to cool and move around the rest of the home.
So you're saying to just let the servers get as hot as they want and ignore it? What is this heat pump going to be heating?
If you don't have anything you are wanting to heat up, adding a heat pump doesn't help.
Modern heat pump systems are reversible, so you would be drawing the heat energy from the room and releasing it outside. During this exchange air is run over a compressed coolant which cools the air and reintroduces it back to the room.
That's just called an air conditioner?
An AC can only cool the home, while a heat pump can both cool and heat a home. They are different things, and worth looking into.
During this exchange air is run over a compressed coolant which cools the air and reintroduces it back to the room
That's just an air conditioner. The difference between an air conditoner and a heat pump is that a heat pump has a reversal valve that allows the refrigerant to run backwards through the system.
My point is someone is using a whole bunch of words to say "I'd air-condition my server room". It's not exactly a ground breaking idea.
A heat pump still costs energy to run... And running it in reverse to cool a room is the exact same process as running an ac to cool a room. It's all phase change cooling which we've been doing for decades. The only possible innovation that could be had here is using the waste heat instead of just releasing it to the outside environment, but that requires wanting to heat something else while you need to cool the server room.
I suspect the reasoning here is going to not be obvious so some people so I'll add a little. Heat pumps are more efficient when there's a larger difference between where they're getting heat and where they're putting it. I'm going to call this difference a gradient, because otherwise later I'll be saying "differences of differences" which gets confusing. The argument here is that moving heat from compartmentalized 90 degrees server room to outside at 95 degrees with a separate system for the house, moving from 75 degrees to 95 degrees, would be more efficient than a single heat pump moving air from the mixed rooms at 80 degrees to 95 outside.
The magnitude of that effect would depend on how nonlinear the relationship between efficiency and the gradient is. I'm not very familiar with that. I assume it's nonlinear, but whether it's highly nonlinear from a gradient of 5 to a gradient of 20. From here, it's quite nonlinear from a gradient of 25 to 40, but from 5 to 20 it's pretty linear: https://www.ecosia.org/images?q=heat%20pump%20effeciecy%20vs%20temperature%20gradient#id=598B80C1EB5A721C392964CB7708512FC496B78F
This also doesn't consider that these are operated with thermostats. Presumably someone is going to set all of the thermostats to the same temperature, 75 degrees or whatever the preference is. The gradient at which the pumps start will be the same in all cases, and the difference will be in how often the pumps run. There will differences in the average efficiency because of the time difference, but it's by no means obvious to me that there would be a significant benefit for a typical home. I would want some clear evidence before spending money on this.
Edit: I said they're more efficient when there's a larger gradient, but I should have said the efficiency depends on the size and direction of the gradient. When the gradient is positive, it's less effecient. Overall, the conclusion is the same. It's dubious that, for this case, using two heat pumps with compartmentalized rooms provides a tangible benefit over a single pump with mixing.
Being 50% more efficient doesn't mean doing twice the work costs less. The bigger the gradient, the more work it's doing. All that means is an exceptionally hot day won't cost exceptionally more to cool your house than a cooler day.
Instead of the HVAC system cooling already warm air made from the servers, you would partition the lab from the rest of the house and HVAC system, and then install a heat pump for just the room.
The heat exchange would take care of the lab, and the HVAC system would have to circulate less hot air through the system.
Well, was mostly making a joke but would be pretty cool. I’ll bet there’s some way I could figure out how to use the waste heat to offset the water heater or something.
Hmm, liquid cooled.. now you have me thinking :).
Data center heat, with a little external help, warms homes of nearby residents. Nothing unusual or interesting.
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Can you grow on it? Would be the first good thing that comes out of it...