Waste heat from data centers can boost air temperatures in downwind neighborhoods by as much as 4 degrees Fahrenheit, researchers at Arizona State University report in a new study conducted in the Phoenix metro area, the hottest in the U.S.
I gotta wonder, given the power bill of these sites, why they’re letting so much heat energy out into the atmosphere
Surely at least some of that heat could be tuned back into electricity. Yeah it’s not gonna pay all the bills, but surely at a certain level of scale, there’s gotta be some benefit in it just from an economical standpoint, let alone the ecological benefits of not accelerating climate change
Turning waste heat into electricity is a very old goal but it really does come up against problems with entropy fast. Basically if you have a LOT of heat in one place you can boil a great deal of water and make electricity. If you have a lot of heat spread over a wide area there’s no good way to “herd” it together enough to boil water in appreciable amounts.
For the same reason why they let so much water evaporate. They could convert some of that heat back into electricity, just like they could run closed-loop cooking systems, but it would cost more money than it would save. There’s no financial incentive to do so…
… Until regulators start insisting! These datacenter folks have gobs of money, we shouldn’t be shy about requiring them to not ruin the local environment.
It would be best to do it on a national level, otherwise these folks will just shift the development to someplace without the regulations.
Entropy is central to the second law of thermodynamics, which states that the entropy of an isolated system left to spontaneous evolution cannot decrease with time. As a result, isolated systems evolve toward thermodynamic equilibrium, where the entropy is highest. “High” entropy means that energy is more disordered or dispersed, while “low” entropy means that energy is more ordered or concentrated.
They might be able to harness energy from the flow from warmer to cooler areas, but whether or not they do that, at the end of the day, they have to let the heat go, just like a power plant that uses water-evaporation-assisted cooling. If they’re near the ocean, they can maybe stick it into the water instead of the air, and maybe to some degree, you can stick heat into groundwater. But they can’t just take a unit of heat and convert it into a unit of useful work and not have that unit of waste heat.
You can, in areas that have a use for heat, make use of that waste heat. For example, district heating can make use of the waste heat from a power plant — you pipe steam or something from the power plant that you want to be cooler to homes that you want to be warmer.
District heating (also known as heat networks) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating and water heating. The heat is often obtained from a cogeneration plant burning fossil fuels or biomass, but heat-only boiler stations, geothermal heating, heat pumps and central solar heating are also used, as well as heat waste from factories and nuclear power electricity generation. District heating plants can provide higher efficiencies and better pollution control than localized boilers. According to some research, district heating with combined heat and power (CHPDH) is the cheapest method of cutting carbon emissions, and has one of the lowest carbon footprints of all fossil generation plants.
If you live somewhere where that works, it’s basically “free” heating from an energy standpoint, which is cool. Much of the US isn’t well-suited to residential district heating, because we tend to have residences in low-density suburban areas that are pretty spread out and where it’s a pain to transport heat around, but we do have some district heating in city cores. Manhattan, which is one area where we do have high density, famously uses steam heating.
Today, Con Edison operates the largest commercial steam system in the world (larger than the next nine combined).[4] The organization within Con Edison responsible for the system’s operation, known as Steam Operations, provides steam service to over 1,700 commercial and residential customers in Manhattan from Battery Park to 96th Street uptown on the west side, and 89th Street on the east side of Manhattan. Roughly 27 billion pounds (12,000,000 t) of steam flow through the system every year.
For that to work, you have to actually have some use for that heating (and you probably only want heating some of the year, unless you’re up in the polar regions or on a mountain or something).
You can also use waste heat to drive industrial processes that require heat, but waste heat from a datacenter isn’t super-hot compared to, say, that from a power plant, so I don’t know how interesting that necessarily is. Lots of chemical processes that might require elevating something to a much higher temperature, but a datacenter — at least using current computing hardware — normally tries to keep temperatures from getting to something like the boiling point of water.
Some greenhouses will also use waste heat (in the case of power plants doing cogeneration, some of the waste carbon dioxide as well) to help boost plant growth.
and maybe to some degree, you can stick heat into groundwater
Do it long enough, and even that would become a problem. There are parts of the London Underground that are uncomfortably hot to ride because it’s existed so long they’ve managed to heat-soak the ground around the tunnels.
The heat in the tunnels is largely generated by the trains, with a small amount coming from station equipment and passengers. Around 79% is absorbed by the tunnels’ walls, 10% is removed by ventilation, and the other 11% remains in the tunnels.[3]
Temperatures on the Underground have slowly increased as the clay around the tunnels has warmed up; in the early days of the Underground it was advertised as a place to keep cool on hot days. However, over time the temperature has slowly risen as the heat sink formed by the clay has reached its thermal capacity. When the tunnels were built the clay temperature was around 14 °C (57 °F); this has now risen to 19–26 °C (66–79 °F) and air temperatures in the tunnels now reach as high as 30 °C (86 °F).[3][4][5]
The primary issue is that there’s a limit to how much energy you can get out based on the difference in temperature between the cold fluid (liquid or gas) and the hot fluid. With data centres it’s maybe 20°C? Based on that assumption and the Carnot Theorem you get a maximum work extraction efficiency of about 6-7%.
Unfortunately, in the data centres they obey the laws of thermodynamics.
It would work better in places that get colder, but unfortunately places like that don’t tend to have as much available electricity (or infrastructure).
An aside:
We are starting to run up against fundamental laws of how much energy is required to do a certain amount of computation. i.e. In order to do a computation that moves a system from a state X to another state Y, there is a minimum amount of entropy change. That entropy change requires a certain amount of energy based on thermodynamics, known as the Landauer Limit.
We were already only about a billion times less efficient than the limit in 2012. I would wager we’ve improved computation per watt by 1-2 orders of magnitude since then. Which means we might only be 107 or so off of the limit. That sounds like a lot, but when you think about how fast we’re improving…
Yeah, this is fundamental; if you use a thousand joules of energy to do work (of any kind) you will ultimately end up producing a thousand joules of waste heat. The only choice one has in the matter is where that heat goes.
This is a major reason why I get annoyed at the people pooh-poohing space-based data centers. It literally puts the waste heat outside the environment. It should be everything that data center opponents say they want.
That article was incorrect, then. There are many satellites already in orbit that have computers in them - basically all of them do, nowadays - and cooling them is a well understood engineering problem.
Which means they’re not as useful, way more expensive, existing ones can’t be serviced or upgraded and they won’t be able to keep up with induced demand. I.e. they’re not practical. Just because something is theoretically doable doesn’t mean it will actually work for what want it to do.
Also cooling chips in space is something we had to solve in order to explore and have satellites whereas the lack of AI data centers in an invented problem. There’s no actual need or demand for them.
Also there’s not enough money (actually money, not imaginary money that our financialized economy makes) to pay for it even it where practical to do. They’re not even able to afford the normal ones lol. Orbit based data centers ain’t happening.
Space-based data centers are wildly impractical to bordering on not physically possible. The largest feature on the ISS, which you can resolve from earth with a pair of binoculars, is the radiators, and it generates 70 kW. Large data centers use >100MW of electricity. You’d be looking at large fractions of a square mile of just radiators.
The radiator panels on the ISS are 2,500 square meters in area. The radiator panels are 645 square meters.
Most of the proposals for space-based data centers have ended up focusing on plans to place thousands of individual satellites into orbit, not just one big space station with everything packed inside it. Scott Manley recently did an analysis of the cooling requirements, he worked through all the numbers and explained how it works, and there really doesn’t seem to be a problem here.
I gotta wonder, given the power bill of these sites, why they’re letting so much heat energy out into the atmosphere
Surely at least some of that heat could be tuned back into electricity. Yeah it’s not gonna pay all the bills, but surely at a certain level of scale, there’s gotta be some benefit in it just from an economical standpoint, let alone the ecological benefits of not accelerating climate change
Turning waste heat into electricity is a very old goal but it really does come up against problems with entropy fast. Basically if you have a LOT of heat in one place you can boil a great deal of water and make electricity. If you have a lot of heat spread over a wide area there’s no good way to “herd” it together enough to boil water in appreciable amounts.
For the same reason why they let so much water evaporate. They could convert some of that heat back into electricity, just like they could run closed-loop cooking systems, but it would cost more money than it would save. There’s no financial incentive to do so…
… Until regulators start insisting! These datacenter folks have gobs of money, we shouldn’t be shy about requiring them to not ruin the local environment.
It would be best to do it on a national level, otherwise these folks will just shift the development to someplace without the regulations.
To harness useful energy from heat, you have to let heat flow from hotter areas to colder areas, to permit entropy to increase.
https://en.wikipedia.org/wiki/Entropy
They might be able to harness energy from the flow from warmer to cooler areas, but whether or not they do that, at the end of the day, they have to let the heat go, just like a power plant that uses water-evaporation-assisted cooling. If they’re near the ocean, they can maybe stick it into the water instead of the air, and maybe to some degree, you can stick heat into groundwater. But they can’t just take a unit of heat and convert it into a unit of useful work and not have that unit of waste heat.
You can, in areas that have a use for heat, make use of that waste heat. For example, district heating can make use of the waste heat from a power plant — you pipe steam or something from the power plant that you want to be cooler to homes that you want to be warmer.
If you live somewhere where that works, it’s basically “free” heating from an energy standpoint, which is cool. Much of the US isn’t well-suited to residential district heating, because we tend to have residences in low-density suburban areas that are pretty spread out and where it’s a pain to transport heat around, but we do have some district heating in city cores. Manhattan, which is one area where we do have high density, famously uses steam heating.
For that to work, you have to actually have some use for that heating (and you probably only want heating some of the year, unless you’re up in the polar regions or on a mountain or something).
You can also use waste heat to drive industrial processes that require heat, but waste heat from a datacenter isn’t super-hot compared to, say, that from a power plant, so I don’t know how interesting that necessarily is. Lots of chemical processes that might require elevating something to a much higher temperature, but a datacenter — at least using current computing hardware — normally tries to keep temperatures from getting to something like the boiling point of water.
Some greenhouses will also use waste heat (in the case of power plants doing cogeneration, some of the waste carbon dioxide as well) to help boost plant growth.
Do it long enough, and even that would become a problem. There are parts of the London Underground that are uncomfortably hot to ride because it’s existed so long they’ve managed to heat-soak the ground around the tunnels.
That’s a neat tidbit.
https://en.wikipedia.org/wiki/London_Underground_cooling
Fun fact: in switzerland some companies like Infomaniak do give excess heat to the near houses, it’s such a cool thing
This guy heats.
The primary issue is that there’s a limit to how much energy you can get out based on the difference in temperature between the cold fluid (liquid or gas) and the hot fluid. With data centres it’s maybe 20°C? Based on that assumption and the Carnot Theorem you get a maximum work extraction efficiency of about 6-7%.
Unfortunately, in the data centres they obey the laws of thermodynamics.
It would work better in places that get colder, but unfortunately places like that don’t tend to have as much available electricity (or infrastructure).
An aside:
We are starting to run up against fundamental laws of how much energy is required to do a certain amount of computation. i.e. In order to do a computation that moves a system from a state X to another state Y, there is a minimum amount of entropy change. That entropy change requires a certain amount of energy based on thermodynamics, known as the Landauer Limit.
We were already only about a billion times less efficient than the limit in 2012. I would wager we’ve improved computation per watt by 1-2 orders of magnitude since then. Which means we might only be 107 or so off of the limit. That sounds like a lot, but when you think about how fast we’re improving…
Yeah, this is fundamental; if you use a thousand joules of energy to do work (of any kind) you will ultimately end up producing a thousand joules of waste heat. The only choice one has in the matter is where that heat goes.
This is a major reason why I get annoyed at the people pooh-poohing space-based data centers. It literally puts the waste heat outside the environment. It should be everything that data center opponents say they want.
So that’s where they put the front after it fell off? Space?
I read an article a month or two ago that explained without an atmosphere to carry away the heat, the chips would just super-heat and melt.
That article was incorrect, then. There are many satellites already in orbit that have computers in them - basically all of them do, nowadays - and cooling them is a well understood engineering problem.
The satellite computers don’t perform as much work, produce as much heat, or are as densely placed as those in the data centers.
So don’t pack them as densely as Earth-based data centers are packed.
In another comment in this thread I posted a link to a youtube video by Scott Manley explaining the math and engineering behind cooling computer hardware in space, it’s actually pretty straightforward.
Which means they’re not as useful, way more expensive, existing ones can’t be serviced or upgraded and they won’t be able to keep up with induced demand. I.e. they’re not practical. Just because something is theoretically doable doesn’t mean it will actually work for what want it to do.
Also cooling chips in space is something we had to solve in order to explore and have satellites whereas the lack of AI data centers in an invented problem. There’s no actual need or demand for them.
Also there’s not enough money (actually money, not imaginary money that our financialized economy makes) to pay for it even it where practical to do. They’re not even able to afford the normal ones lol. Orbit based data centers ain’t happening.
It’s another Musk grift. It’s a scam.
How was it incorrect? How can you transfer heat away from the electronics into another medium when there is no other medium because it’s in space?
By that logic, every existing satellite would overheat and die.
The processing on satellites is absolutely nothing compared to a datacenter.
That would be a matter of scale. You’re claiming it’s flat out impossible because of a lack of medium. Different thing entirely
Same way radiation heat works from the sun.
The sun emites a fuck ton of mass. Satellites don’t have mass to emit.
So how does radiation heat work in other places?
Like this? This has no mass either really.
https://images.homedepot.ca/productimages/p_1001318862.jpg?product-images=l
Space-based data centers are wildly impractical to bordering on not physically possible. The largest feature on the ISS, which you can resolve from earth with a pair of binoculars, is the radiators, and it generates 70 kW. Large data centers use >100MW of electricity. You’d be looking at large fractions of a square mile of just radiators.
The radiator panels on the ISS are 2,500 square meters in area. The radiator panels are 645 square meters.
Most of the proposals for space-based data centers have ended up focusing on plans to place thousands of individual satellites into orbit, not just one big space station with everything packed inside it. Scott Manley recently did an analysis of the cooling requirements, he worked through all the numbers and explained how it works, and there really doesn’t seem to be a problem here.
In less fair weather places you could do district heat. Use a data center to provide heat for a few Condo complexes or something.
There are systems that do heat recovery, but that didn’t really help this problem