
Yesterday, I gave background on my experience with this topic
and the idea that “Data Centers are poisoning our communities.”
Water is just about the most common resource on the planet. Just about the most easily accessible and manipulable, and one of the cheapest resources to refine.
That doesn’t mean it’s easy, cheap in absolute terms, or unimportant.
Most public policy issues with water come down to the water being pure enough to healthily drink, or to discharge into the natural environment. As I put it yesterday, “as part of the ‘drank from the garden hose’ generation, I have a lot of disdain for the hype about water pollution in this context.” The difference between potable water and drinkable water is definitional.
One thing I don’t think gets enough acknowledgement: a building produces “waste water” by existing. I recently had reason to calculate the roof run-off of my house, garage and barn, at about 275 thousand gallons per year. That is “OVER A QUARTER MILLION GALLONS OF NON-POTABLE WASTE WATER OMG!!!11!1!”. This is a small family farm.
I covered a lot of this yesterday from the angle of “pollutants”; but to recap: The water in your sink is contaminated. The water in your toilet is contaminated. The water from your roof, and in your garde hose are contaminated. They’re NOT “polluted”. They’re perfectly acceptable to discharge into the ground (via a septic tank) or a municipal sewer. Storm water run-off doesn’t generally get discharged into the same sewer system in cities, but ONLY because it isn’t septic (doesn’t have humans defecating directly into it- unless you’re in Portland or another big left-wing city) and MOSTLY because the sheer volume of it is impractical to treat in the municipal sewage treatment facilities. In fact, a big problem in Portland (as an example reasonably near me) is when heavy rains overcome the stormwater drain capacity and the septic sewers and storm sewer overflow with sewage sludge into the Willamette River. This is an example of a problem of scale and design at big city levels. But the storm runoff of any big building and its surrounding infrastructure like parking lots is naturally going to have literal tons of bird feces washing away at any given time. Sorry folks, the world is not sterile.
This water is not consumed and forever beyond re-use. It isn’t removed from the natural environment; it is BARELY diverted from where it would have gone anyway. But the devil is in the details. Concentration and channeling of runoff is a significant problem because once in place, a building’s runoff always goes to the same place. Over time, that matters a lot, erosion and concentration both being compounding problems.
But for at least a century, we have had some form of stormwater and wastewater planning and permitting process, that has been incrementally improved over that time. It’s NEVER going to be PERFECT. But at some point, the line plotting safety and the line plotting expense cross somewhere deemed to be “good enough” based on data and professional estimation.
Just keep in mind, that at the end of ALL of these water management processes, there are 3 and only 3 places the water can go.
1. Into the air
2. Into the ground
3. Into the ocean (generally via a river)
It doesn’t disappear, and it isn’t ‘consumed’ in the sense of not existing any more. It isn’t ruined. It is far easier to remove contaminants from water than almost anything else. You just distill it. It may not be fit for drinking without processing, but in modern risk management mindsets and legal definitions, no water is “safe for drinking” that hasn’t been processed and tested and monitored. It’s a definitional thing.
Industrial buildings have several options for cooling.
Purely passive air convection is the most basic. Doesn’t work well if there is a big source of excessive heat in the building. But there are some surprising effective low-tech passive cooling designs out there where the whole structure is designed around cooling, rather than other functions.
Open loop systems expose the coolant (for pure open systems, generally water) to the source of heat. This doesn’t mean they flow water over and in contact with the hot thing. It usually means they have a cooling loop, like a radiator in reverse, exposed to the radiant heat of the object needing cooling. The coolant flows through the loop, picks up heat, and is discharged along with the extra energy. Like spraying water from the garden hose on your hot roof during the summer, the water picks up heat and runs off, leaving the surface somewhat cooler than it was.
This is not very efficient, and there is the effluent to manage. It doesn’t scale, and in most cases is not a permitted use of water (you can’t get a building or use permit to do this.)
More commonly, there is a hybrid system. There is a closed loop, and an open loop working together. The closed loop is designed to be efficient at picking up heat, and the open loop is designed to be cheap at discharging it. This is where we get cooling towers and evaporative cooling.
Most of the time, the municipal supply is used by default because it’s a convenient source of relatively clean water to start with. Sometimes it still has to be filtered again prior to use. Some industrial processes use de-ionized water. It can’t even have the normal mineral content that humans NEED in our water (trace minerals) and cannot tolerate the additives like chlorine and fluoride used for sterilization and tooth support, respectively.
Both loops COULD be water. Usually, the closed loop is a liquid with a better ‘coefficient of thermal conductivity’ than water. A material which transfers heat faster, more efficiently, at lower or higher temps without boiling. Water is a great heat conductor, but glycol is better. You can expose glycol to a heat source, then expose the open loop evaporator to the glycol, and the water takes up energy by evaporating into the air. Evaporating water takes almost no other trace elements with it. It’s essentially distilled water at that point. It leaves any mineral content behind. In general, it takes more area to dissipate heat than to collect it. This disparity drives the ‘heat engine”. Taking advantage of area dispersal and gross temperature differences is an old technique and can be pretty cost effective, depending on the cost of water and space (area) to discharge heat. You use fairly cheap fans and liquid pumps, at relatively low pressures, so all the machinery is easy to make and cheaper.
The “cooling chemical”, more properly referred to as coolant or refrigerant, stays in the closed loop. It’s the expensive part, and the part that has potential to affect the environment negatively. We use coolants in ALL KINDS of applications. Refrigeration of food, automobile air conditioners, automobile radiators for cooling the engine, building HVAC systems, and specialized industrial processes. Over the years we have determined some coolants are more problematic than others for disposal or leaks, and standards have evolved in regards to allowable uses and types. The refrigerant used in car AC and home heat pumps has changed a lot in recent decades.
The evaporated water (a small part of the overall water used) becomes rain. The remnant water that is not evaporated (we’re talking large flow for efficiency) has slightly more concentrated levels of whatever mineral content that already existed in it coming from the source. Not high enough to require specialized treatment. This water is not “used up”, or eliminated. It simply isn’t ready to drink without being verified. It does tend to have a higher than ambient temperature, which is the biggest reason not to discharge it into natural bodies of water, as stream temps affect aquatic life and they are adapted to the existing temps. Sometimes the solution is as simple as a settling pond on the premise.
Evaporative systems and most forced heat pumping systems for that matter, have ranges (min/max ambient temperature and humidity) where they are most efficient, and they work best when the differential is significant within that range. If you want to cool a hot space, it’s best if you’re pumping hot coolant to a quite cold place to exchange heat. Evaporative cooling towers work best when the air isn’t already saturated with moisture (high humidity), where the ambient temp is not slow it causes the evaporated water to condense back into the tower or so high the closed loop can’t ‘lose’ heat to it. Altitude and partial pressure of the atmosphere at your location can also matter (see Boyle’s law discussion below).
Inside the cooling equipment there IS a potential to pick up contaminants that affect health. If the cooling equipment is built with substandard materials, solder that isn’t rated for drinking water, etc, some unhealthful metals could leech into the effluent. This doesn’t mean the water is fore ever poisoned or unusable. Building codes require cooling system discharge to be within tolerance before going into municipal sewers, where the water gets treated anyway.
Depending on the municipal water supply’s mineral content (varies wildly across the USA, as long as it is within EPA tolerances), cost, and delivery availability, a closed loop system might find they don’t want the municipality involved. They might have water trucked in, or tap a natural supply from roof run-off or natural water source, and filter it themselves. In that case, the water they discharge could potentially be “cleaner” than what they take in. Again, they have to have permits that have been through the planning and approval process for all of this. The water isn’t being diverted to Mars.
There are also entirely closed-loop systems. These generally do not use water at all. Your kitchen refrigerator is a ubiquitous example. It has two stages, and uses a compressor and Boyle’s law to move heat. When you compress a gas, it gets hotter. When you decompress it (allow it into a larger volume) it gets colder. When you hook up two big BBQ grills to a single propane tank and turn on all the burners, you may let the gas out so fast it freezes the gas in the valve. That kind of thing.
All systems have less than perfect efficiency. A closed loop system still needs top-ups due to leaks, maintenance, etc. But closed loop systems aren’t deliberately discharging coolant at all. They’re just pumping it from one pressure vessel to a different containment to benefit from the changes in ambient heat and pressure. Glycol and other thermally-efficient coolant liquids are expensive. You don’t discharge “cooling chemicals” and refrigerant, you keep it in closed loop systems. Data centers are hardly the only, or even primary user of this tech. Most office buildings use it too. Home (window units, heat pumps and mini-splits all) and automotive air conditioning is all closed-loop.
Closed loop systems are more energy intensive than open loops systems with evaporative towers. You’re forcing higher and lower temps through pressure changes, more than simple heat exchange through exposure and conduction. That requires higher pressure piping, pumps, and more powerful fans. When you do maintenance, you have to pump out the refrigerant/coolant into safe temporary storage and replace it when maintenance is done. Leaks are a bigger risk of contamination (modern refrigerants are less problematic than the past but not without impact.)
Closed loop systems for building HVAC mostly don’t use water as part of the process. People seem to be (deliberately?) conflating power plant (hybrid system) cooling towers with building HVAC. They are not even close to the same thing. Water just isn’t efficient enough at heat transfer to make closed loop systems work well. But even if it uses water for the cool side, and has a REALLY BIG reservoir to do so, that water is maintained in the system, minus only leaks, maintenance, and unavoidable losses of efficiency. It isn’t being “used up”, it’s being used “over and over”.
The word “millions” gets thrown about a lot. It’s a big number. But context matters. A million leaves on the trees in the park only sounds like a lot until you think about it. A million gallons of water is less than two Olympic size swimming pools. It’s a lot of water for an individual, it is not very much for a process or facility that serves thousands of people daily. I pointed out above that my home and barn combined have “over a quarter million gallons” of rain runoff per year. Your home probably has at least half that if you live a rainy place like I do. If you’re an office worker, the building you work in probably doubles it. If you work in a smaller commercial building with a parking lot, probably quadruples it. The data center you’re bitching about almost certainly generates more stormwater runoff than it uses in cooling. These things matter, but they’re generally accounted for in the building planning and permitting process already. It all adds up, but it isn’t a catastrophe, and certainly not a unique, new problem.
The water isn’t gone, and it isn’t ruined forever. Data center cooling systems are not going to turn your home into a desert. If you already live in the desert, you won’t notice a difference.
Data centers are ALL AROUND YOU. You don’t even know they’re there. They are just another ugly industrial/commercial building and you have no idea what is happening inside. Many of them are in one or two floors. Or the basement of an office building. A bigger national chain bank building almost certainly has a datacenter in it. I’m not saying there is no negative impact to them. Lots of reasons to not want a big industrial building next to you. But plenty of reasons to want them to exist: without datacenters, you would have no electricity at your house to read this, no Internet to read it from, and you’d be using metal coins and paper folding cash to pay for everything.
It’s quite likely that the AI Hype is causing over-speculation into data center investment. But since a data center can be housed in nearly any modern commercial building shell, that construction will be largely fungible. Right now, a great deal of the discussion is on how much heat this dense computing will generate, but efficiencies in that aspect of computing have been a target for a long time, and it keeps improving. Crypto-mining has largely jumped the shark, so super dense GPU card (a very hot tech, literally) manufacturers are probably loving this hype right now, and salivating over anticipated sales to replace the waning enthusiasm for crypto-mining as electricity prices have risen… but here is a prediction. Over the next 24 months, this market segment will cool off significantly.
As more big tech companies (and some of them are already backing away) fail to find the expected benefits and savings in LLM implementations because it doesn’t live up to the ‘intelligence’ part of AI, and more space and efficiencies are found in existing datacenters and spare capacity on existing cloud infrastructure is found for additional workloads, many of the projects now on the drawing board for discussion will be cancelled or scaled down.
Some form of this tech is going to be with us for the long haul, but we are not currently on the path to machine consciousness, and the appeal of a digital sycophant designed for addictive levels of engagement rather than useful computing rigor, is already wearing thin. The base of this tech is too heavily entwined with social media algorithms to be a great base for helping us live a better life. It is a useful but flawed tool, and it is designed for things most of us don’t actually want while being marketed to us as something it isn’t.
If I’m wrong about it*, in 2 years you have my permission to throw pumpkin pie at my face, as long as some lands in my mouth.
Larry Good, Author at Ordinary Times
Facebook: Lawrence Good, Scribbler
*Y’er wrong about it, Larry. It’s just right now few people have any idea how to use it, but those are massively more productive than they ever were, and that is going to redound in marked benefits as we go on.
Also we’ll all find uses (better uses than now) for them as we go on. It takes time. What you’re saying is the equivalent of “Computers are a fad. They’re not useful for most of us.”
This is said without prejudice, because at least you’re arguing in good faith, instead of trying to panic us with water or something. I won’t throw pie, but I will reserve the right to say “I was right!” – SAH



















































































