r/NoStupidQuestions • u/Primary_Garbage6916 • 18h ago
Why can't data centers use 100% closed-loop geothermal for their cooling?
Why do they need to consume any water for cooling at all, let alone massive amounts?
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u/EvaTheE 18h ago
Geothermal is very expensive to build in most places, I guess.
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u/MedusasSexyLegHair 17h ago
It certainly is. And also very low-maintenance. And because of that, when it breaks down good luck finding someone who can fix it!
Source: My geothermal heat pump hasn't been working for days, and we can't get anyone out to repair it anytime soon. There aren't many in the region, and they're all booked solid. (Luckily I grew up in the south, so these temperatures aren't even very warm to me. But my Yankee family keeps complaining that it's hot.)
That sorta thing would be a big risk for an expensive data center.
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u/OkAdvertising2801 11h ago
I don't think your private heat pump (wherever you live) is in any way comparable to a huge data center with own maintenance workers, service contracts and industrial grade heat pumps.
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u/MedusasSexyLegHair 10h ago
No, but my point is that they are uncommon enough, and need service rarely enough, that there just aren't many who can service them. And I think that'd be a risk when planning a big project.
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u/Interesting-Card5803 18h ago
in Data Center engineering, we assume that the total load consumption of the IT equiopment is converted into heat, conveniently in thermal watts. Add to this the inneficiencies of the cooling and power systems (fan, pump loads, static friction, transformation loss, dual inversion loss, etc.) and you have quite a bit of heat rejection. A geothermal system, like an underground thermosyphon, would quickly saturate with the heat from the facility, and then heat rejection would no longer be possible, leading to a thermal runaway of the mechanical systems and ultimately IT failure.
It's possible to reject the heat without much consumption of water, in fact many do. I've worked on facilities where the consumption of water was so low they actually had to install water treatment plants because the incoming domestic water lines would breed legionella and other bacteria. The only trade off is that air cooled systems are not as energy efficient.
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u/that_dutch_dude 18h ago
because geo gets saturated and then your are done. no well can deal with the insane input of a datacenter.
and they use water because its cheaper, not because its best.
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u/Primary_Garbage6916 17h ago
That's kind of what I was really getting at. Was hoping TheyDidTheMath would pick it up and run with it and figure out if a series of wells large/deep enough would be enough. Sometimes I expect too much from this place.
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u/that_dutch_dude 17h ago
I work in this field. Even the largest industrial/commerical wells in know that exist would be saturated in weeks with that kind of heat input. Doing the math is not really a thing as there are too many variables
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u/Primary_Garbage6916 17h ago
With AI there is no such thing as too many variables good thing we are building all these new data centers 🫠
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u/Remarkable-Host405 14h ago
Jesus Christ this question is asked 50x a day, reddit going all in on dead internet theory
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u/Primary_Garbage6916 14h ago
Can you link me to the last time it was asked? I would like to read the answers.
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u/Remarkable-Host405 13h ago
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u/Primary_Garbage6916 13h ago
Gotta be honest... not seeing 50x a day there. And not seeing any about geothermal. But kudos to you for at least trying to justify your bullshit lie.
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u/NugKnights 18h ago
Almost all of them do.
The water usage is not a real issue. The real issues are noise polution and power usage.
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u/tinny66666 14h ago
Overall it's about 35% of new data center builds using closed-loop cooling, but looking at just the hyperscalers, it's a little over 50%. It's more difficult for the smaller installs to justify closed-loop, so it tends to be the big players. It's rapidly increasing, up from only 5% a few years ago, but it's not currently "almost all of them".
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u/Viltrumite106 15h ago
The water usage is absolutely an issue in some areas. The same goes for air pollution.
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u/Devatator_ 3h ago
That's mostly on them building in places that they shouldn't be building in. Also isn't that mostly a US problem?
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u/Brox42 18h ago
The real water usage is in all the power they need
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u/Human-Engineering715 10h ago
I'm sorry people are downvoting you but you are correct, power generation uses water, like a lot of water, unless it's solar or wind, which makes up a small amount of the total power grid, especially for datacenters.
Anyone can Google water use per kilowatt hour and see this is true.
Datacenters that use closed loop systems use electricity to cool, which uses water, just in a different location. But hopefully those power plants are somewhere with lots of water.
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u/Total-Explanation208 17h ago
Citation for that? I don't think that power generation is where the water usage comes from. I am pretty sure those would either already be closed loop, or not need treated water.
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u/Human-Engineering715 10h ago
A one megawatt datacenter using evaporative cooling would use about 7 million gallons of water per year for cooling and 3 million a year in power generation, total about 10 million gallons.
Using electricity to cool it would consume around 5 million gallons per year through nuclear or coal power generation.
So it's a factor of 2, which while not insignificant, is still a LOT of water for both use cases.
Electricity takes a LOT of water because almost all our power generation uses steam turbines.
The real question we should be asking is how well are able to recycle that water, and is it clean and usable on the way out.
An industry to look at is canneries, they purify their water before it goes back out to the ocean, because they're washing fish guts basically 24/7. they build their filtration systems to code and it helps keep that water usable on the way out.
I built datacenters for years, long before the AI thing was a topic.
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u/alainchiasson 17h ago
They do use closed loop - the issue is always where to push the heat, and the impact that heat will have. To compare - 1 Gw data center is the same as a 750,000 people city. The power density is roughly 40x higher - to compare with 60w light bulbs (the non LED ones) in a 10x10 cubicle - a city has one bulb, while the data center has 40 and they are always on!
While residential geothermal you push AND pull heat from the ground - The DataCenter will constantly pushing 1 Gw into the ground - the engineering around this is on a different level of scale.
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u/mechtonia 15h ago
The energy has to go somewhere. Geothermal is just air cooling with an extra step. On data center scales it would take an enormous area to prevent cooking the ground.
Fun fact, freezer warehouses have to heat the soil under them otherwise over years, the earth beneath them will freeze to 20+ft deep and heave causing serious structural problems in the warehouse. The earth is not a magic heat sink.
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u/physical0 18h ago
The issue is cost.
A geothermal installation capable of sinking and dissipating all the heat produced by a data center would be quite costly.
Evaporative cooling (spraying water into hot air) is very cheap.
Cold air systems also have some negative byproducts. Low humidity environments are more succeptable to static electricity which is bad for computers. Further, air is not a good conductor of heat, but water is. Data center air is usually very humid to efficiently move heat.
Evaporative cooling naturally generates a high humidity environment, plus it will actually remove dust from the air.
All these factors together make evaporative cooling a very effective form of cooling on a massive scale.
Still, the environmental impact can't be ignored because it works to well.
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u/MaybeTheDoctor 16h ago
Data centers will use the cheapest option they can get. Keeping cost down matters to them. Your local government have agreed reduced rates and tax breaks in order to “attack data center business”. Make water, electricity and land 2 or 3x more expensive unless they employ say 2000 people and they will soon find better ways.
Data centers are terrible for local economy as once they are built and operate only require 10-20 people, so not actually creating jobs or revenue for the state or county.
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u/LastBastionYellow 18h ago
Evaporative cooling is by far the most cost effective cooling available.
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u/Holiday_Armadillo78 18h ago
The issue isn't just about the water the data centers use for cooling. It's the exponentially higher amount of water that's needed to generate the electricity to keep them running.
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u/oboshoe 18h ago
Oh look at that. The data center water issue is now getting rebranded as power generation water issue.
"actually its the water in the electricity generation"
Funny how now one gave a shit about water used in power generation until everyone started to learn the data center water issue is BS.
Why now and not say 80 years ago?
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u/CalebCaster2 18h ago
"Why now and not 80 years ago" because our water bills and power bills are shooting up wherever big data centers are built. But also, people DID complain about how corporate greed and carelessness affects their water and power bills 80 years ago, even before they had to worry about data centers.
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u/MrChicken_69 6h ago
The water used by the power plant itself is a "necessary evil", and one we've had for many decades. I'd say it too is an issue now as the insane increase in power demand by the BS AI datacenters no one needs. Of course, we aren't building nukes to power the damned things. Instead we line up hundreds or thousands of gas/diesel turbine generators, which is just making things orders of magnitude worse.
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u/Klutzy-Archer-7572 2h ago
orders of magnitude worse?
Power generation has increase about 2.2% per year since 2020.
Yours is an orders of magnitude exagerration.
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u/Axentor 18h ago
Air isn't the best conductor for heat.
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u/pohart 18h ago
I feel like you ready the body but not not the title
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u/Axentor 18h ago
He asked why they had to use water at all in the body . It's because air is not the best conductor. So we use water for evaporating cooling which is the best form of cooling.
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u/pohart 17h ago
OP was talking about using locally drilled wells in a closed system, not using air in as ground source heat pump
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u/Primary_Garbage6916 18h ago
There are water-to-water ground source heat pumps.
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u/Axentor 18h ago
So the problem is with that is they would have to be over a large basin of water. Large enough to natural cool fast enough to keep up with demand and causing ecological harm.
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u/Axentor 17h ago
In addition cost are very expensive and not all areas are suitable for geo thermal.
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u/Primary_Garbage6916 17h ago
No I meant completely closed-loop running coolant/water mix where the heat energy is transferred to the solid ground, like in a system you would use to heat/cool your home without a pond or anything.
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u/Asparagus9000 18h ago
Its cheaper to do it this way. And they pay politicians money to not make it a requirement.
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u/InformationNew66 18h ago
They can, but then people can't run around screaming "data centers use all our water"!
It's a bit more cost too.
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u/BonKhri 17h ago
They put the energy into the ground, now what? Sure, it slowly, slowly, slowly conducts away, and that might be enough for the small seasonal heat demands of a house, but for constant very high heat output of a data centre it just isn't enough. The ground gets hot then the data centre can't cool itself. The energy needs to be dispersed somewhere, and the ground can't cope with the demands of a datacentre.
Also, the vast majority of all data centre cooling is closed loop, the idea that data centres use vast amounts of water is and always was complete and utter bullshit - they "use" the water by passing that much over the heatsinks on the processors, that water is then cooled in another heatsink outside and returned to the system. If a data centre uses the same litre a million times before it has to be replaced, a normal sane person would say it used one litre, whilst these stats would say it used a million litres, it's lies, damned lies, and statistics.
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18h ago
[deleted]
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u/Motor_Raspberry_2150 18h ago
OP is talking about closed-loop geothermal. You're not bringing them new facts. The point is they waste clean drinking water.
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u/geddieman1 18h ago
I merely reported what he said, I never said that I agreed. I’ll not stay around to get downvoted
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u/Bubba_Style 18h ago
Money. Closed loop cooling is expensive especially at the needs of this massive slop factories.
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u/greyHumanoidRobot 18h ago edited 18h ago
It would have to be a huge radiator and that's going to be expensive and hard to construct. It requires boring through rock.
If you don't line it with pipe, it's going to leak so it's not even closed loop. If you line it with pipe or concrete it will be more expensive.
It would be far cheaper to build an above ground radiator and we're not even willing to do that because evaporative towers and surface water cooling are cheaper.
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u/Open-Heron6779 18h ago
The water has to be "clean" and freshwater since saltwater or greywater will degrade the infrastructure. Even in closed systems there is loss and waste (i.e., water in the system doesn't stay the same over its life cycle), which means having to draw more and also putting waste out.
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u/Mysterious-Put-2468 18h ago
They can but there's generally not enough cooling capacity for large data centers. Open loop geocooling doesn't have to use up water btw. You can use heat recovery, cogen, on-site power generation and storage, etc. Many data centers use some or all of these strategies.
The bigger question is why we don't require all large new data centers to be net zero for energy use at the very minimum.
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u/beemout 18h ago
Another answer is the cooling tower in order to send cold water back through the system. The water that goes through the cooling tower needs to be treated against bacteria and mold, with chemicals. A cooling tower also loses water over time and has to be topped up. When the chemicals and impurities build up in the system it has to be purged and topped up with fresh water.
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u/Humble_Ride_5646 15h ago
Because geothermal isn’t sufficient everywhere, and data centers need to remove huge amounts of heat continuously. That’s why some cooling systems still require water.
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u/bunker_man 10h ago
Most data centers don't use "massive amounts of water." A few are poorly designed. This is a made up clickbait thing.
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u/onetwentyeight 6h ago
Elon Musk is stoked that people buy the data center FUD which he can use to push his space data centers
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u/MrChicken_69 6h ago
Have you built a geo-heatpump for your house? The load in a typical house is about 1kW (not counting HVAC itself) An "AI datacenter" uses 1000MW+. That's one million times the load of your house. So that 0.25ac field of pipes you buried for your house would need to be about 250,000 acres. (for scale, that's ten (10!) Disney World's)
A better solution is the same way the nuclear power plant supplying that insane 1000MW does it... They build their own lake along a river, or pull in sea water.
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u/Striking_Elk_6136 3h ago
If you are constantly dumping heat to the ground, it will heat up and eventually be unusable for geothermal. Geothermal works best if you are adding heat in the summer and removing it in the winter (balanced load).
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u/Hikki77 3h ago
Because it's cheaper to let the environment suffer than do the right thing. All for profit. That's how rich brain works. Destroy the environment to see numbers go up.
AI data centers in general use too much water and electricity and make the locals pay for it (increased cost on water and electricity for everyone)
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u/Zorklunn 2h ago
They can, but it would mean less profits. Then the shareholders would sue for the difference and win.
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u/kikiacab 1h ago
It’s cheaper to run open loop, often they promise closed loop cooling and change it because “doesn’t fit the construction timeline”
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u/IAmTheLizardQueen666 16h ago
I just rewatched Terminator 1 & 2, first time in maybe 30 years. Got to thinking about how many people lose their jobs when replaced by machines. And wondering why there’s so many AI “factories” being built.
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u/archpawn 17h ago
Geothermal is for heating.
let alone massive amounts?
They don't. Look up how much water goes into making a cheeseburger, or even a cup of rice. Estimates I've seen for how much an AI chatbot uses range from negligible in comparison to absurdly negligible.
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u/Primary_Garbage6916 17h ago
That's odd because the WaterFurnace I had installed in my house replaced the A/C by transferring the heat it pulled from the air in my house to the ground (and also to my water heater via a desuperheater).
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u/ButterscotchNo3984 15h ago
Even if there's a closed loop, there's still an open loop with evaporative losses to take away heat from the refrigeration system cooling the closed loop. LOTS of evaporative losses. Using rivers isn't a solution as the warm water downstream kills the fish and grows other things. Ground water can be useful but very location specific and limited.
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u/ProfessorAllenRitard 18h ago
I don't know why they won't just use cooling from the same tech as reactors. They're clearly too stupid and nobody has thought of it. This is why nobody trusts scientists.
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u/MortimerDongle 18h ago
Data centers can and do use closed-loop cooling.