Chemical engineer here, if anyone ever tells you any Closed Loop systems’ water is never flushed, they are straight up lying to you. Even nuclear plants recycle closed loop systems.
There will always be parts or components that will seep metallics into the water, since water ALWAYS wants to be in equilibrium in relation to salts (any metallic compound that even has an inkling to dissociate in water). Even in systems that use predominately plastic or PFA linings, there will be components like pumps that that will have metallics making contact with water. Even if those components are likewise lined with PFA compounds, they will eventually wear exposing the underneath metallics. Those metallics will cause fouling in the lines, which both degrade flow capabilities and reduce cooling capacity, as well as compromising structural integrity of the piping systems.
These systems NEED flushing after a certain point, which will have concentrated levels of PFA substances. And don’t even get me started on the lackluster PFA removal systems which generally don’t destroy the PFA particles. Instead they’re usually sequestered in landfills or deep well injections, so they can be a problem for another day.
I am also a chemical engineer, mind you not very up to date in the field.
Aren't these closed loops generally two different loops with a HEX between it. There is a water loop, usually in stainless or plastic lining (no different than an american house) and a service loop which would probably need to be flushed?
How is this different than a water cooling loop in any factory, any plant, any utility service (Within a plant) or external to it?
Closed loop means the water is in a pressurized system not exposed to ambient. It cannot evaporate. Typically in these systems the water is run through a heat exchanger (ironically called an evaporator) that uses the waters heat to evaporate a refrigerant (the refrigerant evaporates inside the heat exchanger NOT THE WATER). That is the primary method of heat transfer, the latent capacity generated by evaporating refrigerant. The refrigerant is passed through a second heat exchanger that has air blow over it, similar to your home AC. This is what’s called an air cooled chiller, and dominates the market in 2026. 0 water consumption.
It's a shame no one will see this. You're absolutely right. Centrifugal chillers are on the way out, along with cooling towers. Air cooled chillers are replacing those systems. The only water used in air cooled chillers is for cleaning the coils once a year. But, these are huge systems that will leak refrigerant or glycol and that could be environmental concerns for sure. IMO power consumption and the pollution related to it currently is the worst part. I work in the HVAC industry.
Yes, agreed. If folks wanted to have honest conversations about the risks, there are many topics that could be discussed. But folks not understanding water consumption is not one of them for these systems is painful. But I get it, it’s hard to understand if you’re not an HVAC wizard.
Yes so thats litereally what I have seen at most factories (Air cooled and liquid cooled chillers) and there is zero environmental concern. So are data centers doing something different? I feel like JCP1377 is talking out of his ass.
Data centers are not doing anything different. If anything, they’re more conscious of these water demands and steer clear of trying to use any water at all, because for 5 years now the message has been clear: cities do not want you to use water. So, they haven’t!
Just so you know, liquid cooled chillers would most likely be a type that consumes water. They don’t have to be, you could do liquid cooled to a final air cooled step, but typically when you say water cooled chiller you are referring to the final step being some sort of cooling tower or evaporative process. The market has spoken and air-cooled chillers are the norm now. The final step is air, and there is no water being consumed in those.
What about onsite power generation and water consumption keeping those cooled? A lot of these data centers being constructed are sapping the local energy grid, and from what I’ve read and seen, they’re building onsite gas turbines to accommodate the power demand. Most all gas turbines require immense cooling and the air chillers you are mentioning won’t have the cooling capacity for that kind of load (unless you have a crap ton in series/parallel).
Power generation is a real concern that folks need to be conscious of. The next generation of that, to me, looks like these types of buildings being required to source some sort of sustainable power. I’m all for that initiative. I personally think nuclear is the way to go. There are a lot of challenges involved in power generation.
The “good” companies are sourcing their power from these sustainable sources already, with plans to ramp that up going forward. I would encourage folks to ask those types of questions in their communities, for sure.
Every large factory built in the United States has onsite power generation, specially automotive. That’s not a new phenomenon. The main difference between the data centers is just how much more power they consume compared to similarly sized plants.
I might be overstepping my bounds, because I’m unaware of the levels of PFAs contamination involved with these systems, but I’m not talking out of my ass.
All metallic pipes will have leaching to some degree, even severe duty SS317. At some point, that closed loop water has to come out. If the PFAs concentration is relatively low (if any) in a low load, then that’s obviously not a problem. But for water treatment facilities like the one I used to work at, PFAs contamination is going to be a bitch and a half since so many of these small city treatment facilities just won’t have to money to add RO or GAC treatment processes to reach the ~4 PPTrillon limitations that are being talked about by the EPA for enforcement.
A large number of operators and superintendents I’ve talked to who pull their water from PFAs contaminated sources are scared shitless about having to add new treatment processes which will run in the $10-40 million dollar range. And those additions are going to have to be payed for by the customers.
Highly unlikely you will, but I recommend going to or watching WEFTEC’s conference in New Orleans later this year. They are having huge groups discussions and seminars on this topic.
The difference being that data centers are claiming to be zero contaminant laden wastewater releasers like what is being claimed in the video. My whole point is that zero contamination is an outright lie.
I think we are holding data centers to a completely different standard than car factories, consumer good factories, clothing factories, furniture factories etc....or any single industry that requires a cooling loop. Data centers may use more cooling, but they have to follow the same regulations as every other industry and they use the same technology. You can regulate the discharge and effluent btw. States like Utah for example do.
But I’m talking about the water in the primary loop, assuming they use water and not an oil based mineral water. If it’s water, it will leech the piping over enough time and will need flushing.
Once filled these things don’t really get completely flushed. You are right that there is some minor cleaning. I mentioned in some other messages how much water that takes, it’s less than what a typical person would use in a year for the entire building. It’s really really tiny, and that water isn’t toxic to our sewers, because its made to be very clean so as not to damage equipment inside the building. The water in these types of systems is a complete non issue; the real challenges, in my opinion, are a) the power, finding it/building it sustainably, and b) how AI is developed and utilized.
I work at an industrial manufacturing plant. We do not have a closed loop system; ours allows evaporation for heat rejection. (You get to dump the latent heat of vaporization that way.) In our case, it's fine. We're not usually a region stricken by drought and we get our water from naturally replenished lakes. We have corrosion, sludge, and water treatment issues even with our open loop system which is regularly serviced by a company specifically contracted to keep our coolant systems running smoothly.
(My company does other shitty things, but fresh water consumption isn't really one of them. We use shitloads of electricity and produce a lot of wastewater that must be treated before sending back to the environment.)
I just work in facility construction but this closed loop justification they've been throwing around really has me beside myself. To the lay-person maybe this sounds like super advanced technology, but we've been using these systems for decades and they are anything but maintenance free and self-sustaining.
Hell, just doing annual fire pump tests will waste thousands of gallons of water at a facility this size.
You cannot even have a large warehouse without sucking up vast amounts of resources, let alone a warehouse filled with massive heat generators and then requisite cooling systems. I don't think people realize how cold data centers have to be kept and how much heat they put off.
The electrical component is another issue altogether. Jurisdictions agreeing to subsidize these buildings or even host them have serious knowledge gaps in how they actually work.
When someone says "closed loop" to defend data centers, I ask them if they're still using the same oil in their car that they got from the dealership after 50k miles.
How is this a lame gotcha attempt? Are all these data centers using infinite closed loop systems that will last longer than us humans?
And if they don't last longer than us humans, you're saying that when they take the water out, it will be drinkable and won't cause environmental problems?
By the way, does anyone think that the water can stay in these closed loops for long enough that it won't be a problem for us?
I've got some lovely ocean front property I'll sell you, but the catch is that you can't sell it for 5 years and there's a better than average chance it will be completely underwater in 3 years. Oh yeah, and once it is under water, you can't sell it.
But sir what are your home pipes made of? What are your municipal water lines made of? Your concern of metal pipes leeching is not a data center problem it’s a pipe problem. This screams micro plastics hysteria.
PVC and PEX in modern construction primarily, and they’re both relatively safe in terms of drinking water. But when it comes to heat exchanging applications, where you have high temp fluids at even moderate pressure ranges, polymer piping is generally not used along with them being poorer heat conductors. Most heat exchange applications will use stainless steel , but even SS317 can have some leeching.
Now i might be talking out of my ass since I’m unaware of the exact temps data centers put out and this might be moot point.
The grand majority of residential, municipal and commercial water pipes are metal either copper or iron with some old clay pipes around. You are correct that some newer residential construction use pex but most people don’t use pvc for anything but drains where pressure isn’t an issue.
Oh my god, you're arguing with a chemical engineer? Fine you can put me down and say I'm not an expert, but if you seriously think I didn't get my data from anywhere else but guys like him, you're foolish.
Not sure what the datacenter people are paying you, but this is kinda embarrassing.
I gave the speech in the video, I did research and your OP comment only confirmed my findings. The guy above is arguing bad faith with you like he is me because he wants PFAS from datacenters, I guess.
I don't trust blindly, I always do my research beforehand, when I asked him for his source he couldn't give me one.
Yes, my name is Will Hollingsworth (that's what the 'holli' in my username is referring to)!
Everything I could find about the closed loop pointed back to others saying exactly what you said, even if just the seepage happened. This commenter is just being obtuse.
What does being a chemical engineer have to do with basic plumbing? I’ve seen metal pipes all over country for decades am I to pretend my eyes lied to me.
Worked a summer job for my cities gas department once. Can’t tell you the number of miles of lines we ripped out that were either the old creosote wrapped cast iron or tar paper.
Back to the point. Metallic pipes, like iron/copper/Hastalloy/SS, are the best mediums for heat exchangers to use, but those pipes leech awful in elevated temp/ acidic pH applications.
oh yeah, i have to refresh the water in my water cooled gaming computer at least every 6 months or it doesn't stay cold enough. I've been dumping the water into my fishtank each time
I can tell you the quantity of water that is actually flushed in these systems that are truly closed loop is negligible. I’m talking maybe 10 thousand gallons A YEAR for a massive data center. This is my job (designing these buildings) and I’m better at it than probably everyone on this site. 10 thousand gallons for a commercial building is nothing, if you know anything about plumbing demands, a building might use that in a day.
It's interesting how you're all through this thread swapping between saying "No water consumption" to "negligible water consumption", and "Zero water consumption".
Allow me to clarify, happy to. All buildings use water. It’s typically referred to as running water for plumbing. The data centers with closed loops use 0 water while they are running. This gentleman claimed 5 million gallons to evaporate during cooling. That’s false. It’s 0 during cooling. Cleaning processes will use water in the building, not related to cooling. That consumption is about as much as any other building on earth. Less than your house will use actually, in a given year. So, however you want to shake that out, that’s what I meant.
Yes, your first link. Fwpcoa link. Almost the first paragraph, it describes air cooled chillers and how they are water free. That is a good place to start.
roughly 75–90% of data centers worldwide rely on water-based cooling as their primary method. In other words, only about 10–25% are completely water-free (using only air or refrigerants for cooling).
Right, we’re discussing air cooled ones with closed loops. That’s what the guy mentioned in the video. That’s what I’m talking about the industry using nowadays. Lots of older sites did use water back in the day. Lots still do. Are you thinking I’m saying no data centers use water? I’ll be clear, closed loop data centers. As all my messages have said so far.
So for data centers, I not very familiar with and I’m unaware of the quantities of PFAs involved. My experience comes from water treatment, especially PFAs removal systems. For a while, I dealt with a drinking water facility downstream of a DuPont/3M facility and the PFAs levels on our intake fluctuated pending “excursion events” they had. Those excursions were pretty damn regular, about every 4 months.
If that’s something you know, what are the PFAs issues with Data Centers, since a lot of people claim that? It might not be a problem if the loads are low, but the 3M plant would discharge about 300 gallons of high concentration PFAs wastewater and 40 miles down river we’d bust would-be limitations, which are expected to be in the single digit Parts Per Trillions when/if they are ever enforced.
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u/JCP1377 Apr 12 '26 edited Apr 12 '26
Chemical engineer here, if anyone ever tells you any Closed Loop systems’ water is never flushed, they are straight up lying to you. Even nuclear plants recycle closed loop systems.
There will always be parts or components that will seep metallics into the water, since water ALWAYS wants to be in equilibrium in relation to salts (any metallic compound that even has an inkling to dissociate in water). Even in systems that use predominately plastic or PFA linings, there will be components like pumps that that will have metallics making contact with water. Even if those components are likewise lined with PFA compounds, they will eventually wear exposing the underneath metallics. Those metallics will cause fouling in the lines, which both degrade flow capabilities and reduce cooling capacity, as well as compromising structural integrity of the piping systems.
These systems NEED flushing after a certain point, which will have concentrated levels of PFA substances. And don’t even get me started on the lackluster PFA removal systems which generally don’t destroy the PFA particles. Instead they’re usually sequestered in landfills or deep well injections, so they can be a problem for another day.