4 ms·

Stupid question: datacenters need water for cooling right? But they don't boil that water, ie it comes out of the datacenter just a little warmer? If that is th

by cm2187 9mo ago

Stupid question: datacenters need water for cooling right? But they don't boil that water, ie it comes out of the datacenter just a little warmer? If that is the case does it matter to the city? The warmer water can still be used for agriculture or any other common usage.

jacquesm 9mo ago
It's not a stupid question but: technically, after passing through Google's facility that is now gray water, and you can't use that for agriculture or any other 'common usage' without a whole raft of work and you can't just dump it into the aquifer either.
- DanielHB 9mo ago
  Don't they reuse the water by cooling it outside the data center? Most power plants do that.
  - jacquesm 9mo ago
    Yes, but that does not mean it is now clean water. Anything could happen between the moment Google ingests it and spits it back out, the assumption that it is 'just' a little warmer is nice but it misses the option of for instance contamination from a secondary circuit or various substances leaching into the water used as a coolant.
    - chinathrow 9mo ago
      So where toes the "not clean water" go then usually in such a setup?
      - jacquesm 9mo ago
        Water treatment plants.
    - DanielHB 9mo ago
      But I mean, the water is not discarded, it is constantly reused. I assume some is lost over time, but surely it is minimal?
- cm2187 9mo ago
  But if it just went through some heat exchangers, it's not like if it was dirty? As far as I know, nuclear power plants return the water they consume to the rivers they extracted it from.
  - jacquesm 9mo ago
    Heat exchangers could easily contaminate the water. If they're not kept hot enough they could be breeding ground for Legionella and a whole raft of other bacteria. Clean water is science, not just a matter of bulk pumping stuff from one place to another (though that's definitely a part of it). Water treatment plants are complex and have a ton of QA on their product. You can't just run it into a factory and pretend it is the same stuff going in modulo some increase in temperature.
    - cm2187 9mo ago
      But you are talking about drinking water. I would be surprised if they even use that for cooling. But any non human consumption use of water (like agriculture) should happily use that water, shouldn't it?
      - jacquesm 9mo ago
        No, agriculture has fairly strict standards about the quality of the water, they can't use gray water to irrigate. Of course it will still work but depending on where you live the produce may then no longer be fit for human consumption. You can use it for irrigating your lawn but not for vegetables, especially not if you plan on selling them. But 'light' gray water requires relatively little treatment before you can use it again, however this could still be quite expensive compared to just letting it go. I wonder if they've done any quantitative research on this that's public.
        pera 9mo ago
        That's very interesting, thanks! I had no idea that legionella risk was a thing for data centers. This article mentions that to avoid the risk most data centers treat the water with disinfectants which are sometimes toxic: https://www.scaleway.com/en/blog/making-the-energy-efficiency-regulations-water-smart-the-next-step-for-eu-lawmakers/ https://www.scaleway.com/en/blog/making-the-energy-efficienc...
- direwolf20 9mo ago
  If they can return it to the river how can't it flow to agriculture?
  - mikestew 9mo ago
    It’s gray water, and just as how I can’t dump gray water from my RV camper into the river, neither can a data center. After running through a heat exchanger there can be all kinds of crap in that water.
    - direwolf20 9mo ago
      Data centers and power plants can and do return cooling water from a river back to the same river but warmer. What do you think is inside their heat exchangers but metal and water?
      - mikestew 9mo ago
        What do you think is inside their heat exchangers but metal and water? It's a bad idea to drink hot water from the tap because of the concentration of metals that accumulate in the water heater. Don't assume that a little metal in your water is perfectly safe. As for agriculture, now the metals can concentrate in your lettuce. And, as other commenters have pointed out, what else is in there? How about Legionnaires Disease?
        cm2187 9mo ago
        How is that different from the metal pipes through which drinking water goes through to reach your kitchen tap, some of which are over 100 years old if you live in the UK? The contact with metal shouldn't be the problem in itself. Legionnaires disease either, the water from the river isn't drinking water to start with and the water out of the datacenter wouldn't be drinking water either.
        jacquesm 9mo ago
        When you start of with 'a stupid question' and people then give you lots of reasonable answers and you persist with more such questions at some point you cause me to doubt if you were really asking your first question in good faith.
nonfamous 9mo ago
A lot of it gets converted to water vapor in the evaporative coolers, so it doesn't flow out -- it becomes humidity or clouds. The coolers do also produce waste water, but with all the minerals left behind after evaporation it's not suitable for drinking.
Ekaros 9mo ago
There are multiple ways. Closed loops, well not big deal you fill up and there is slight evaporation losses, but you could ship that in in tanker truck maybe once every few years. Next is open loop cooling using secondary loop. Take a river, lake or sea. Pump some water from it, pass through heat exchanger and pump back out. Manageable for most of the year. Worse version is pump ground water and return it to these. Depletes the ground water... And finally evaporative cooling. Which is boiling, but not at boiling point. Water goes to sky. No immediate return to local ground water or downstream the river... In this case you actually do in sense use up the water. Kinda like burning fossil fuels returns co2 to atmosphere. It will later turn to biomass, but that is a separate cycle.
- progbits 9mo ago
  The CO2 cycle is problematic because of timelines. We are releasing millions of years of CO2 accumulation. Rain is more of a location problem. The evaporated water returns as rain quickly, but maybe somewhere else, such as over ocean. And the aquifer compresses and loses water retention ability.
zvqcMMV6Zcr 9mo ago
> it comes out of the datacenter just a little warmer Exact values matter. Some power plants had been found dumping +10 C water into lakes/rivers, while they had permit only for +5, and it totally destroyed local ecosystem. And most efficient (in terms of money) is evaporation cooling, where at least part of water is "lost".

by cm2187 9mo ago

jacquesm 9mo ago

It's not a stupid question but: technically, after passing through Google's facility that is now gray water, and you can't use that for agriculture or any other 'common usage' without a whole raft of work and you can't just dump it into the aquifer either.

DanielHB 9mo ago
Don't they reuse the water by cooling it outside the data center? Most power plants do that.
- jacquesm 9mo ago
  Yes, but that does not mean it is now clean water. Anything could happen between the moment Google ingests it and spits it back out, the assumption that it is 'just' a little warmer is nice but it misses the option of for instance contamination from a secondary circuit or various substances leaching into the water used as a coolant.
  - chinathrow 9mo ago
    So where toes the "not clean water" go then usually in such a setup?
    - jacquesm 9mo ago
      Water treatment plants.
  - DanielHB 9mo ago
    But I mean, the water is not discarded, it is constantly reused. I assume some is lost over time, but surely it is minimal?
cm2187 9mo ago
But if it just went through some heat exchangers, it's not like if it was dirty? As far as I know, nuclear power plants return the water they consume to the rivers they extracted it from.
- jacquesm 9mo ago
  Heat exchangers could easily contaminate the water. If they're not kept hot enough they could be breeding ground for Legionella and a whole raft of other bacteria. Clean water is science, not just a matter of bulk pumping stuff from one place to another (though that's definitely a part of it). Water treatment plants are complex and have a ton of QA on their product. You can't just run it into a factory and pretend it is the same stuff going in modulo some increase in temperature.
  - cm2187 9mo ago
    But you are talking about drinking water. I would be surprised if they even use that for cooling. But any non human consumption use of water (like agriculture) should happily use that water, shouldn't it?
    - jacquesm 9mo ago
      No, agriculture has fairly strict standards about the quality of the water, they can't use gray water to irrigate. Of course it will still work but depending on where you live the produce may then no longer be fit for human consumption. You can use it for irrigating your lawn but not for vegetables, especially not if you plan on selling them. But 'light' gray water requires relatively little treatment before you can use it again, however this could still be quite expensive compared to just letting it go. I wonder if they've done any quantitative research on this that's public.
      - pera 9mo ago
        That's very interesting, thanks! I had no idea that legionella risk was a thing for data centers. This article mentions that to avoid the risk most data centers treat the water with disinfectants which are sometimes toxic: https://www.scaleway.com/en/blog/making-the-energy-efficiency-regulations-water-smart-the-next-step-for-eu-lawmakers/ https://www.scaleway.com/en/blog/making-the-energy-efficienc...
direwolf20 9mo ago
If they can return it to the river how can't it flow to agriculture?
- mikestew 9mo ago
  It’s gray water, and just as how I can’t dump gray water from my RV camper into the river, neither can a data center. After running through a heat exchanger there can be all kinds of crap in that water.
  - direwolf20 9mo ago
    Data centers and power plants can and do return cooling water from a river back to the same river but warmer. What do you think is inside their heat exchangers but metal and water?
    - mikestew 9mo ago
      What do you think is inside their heat exchangers but metal and water? It's a bad idea to drink hot water from the tap because of the concentration of metals that accumulate in the water heater. Don't assume that a little metal in your water is perfectly safe. As for agriculture, now the metals can concentrate in your lettuce. And, as other commenters have pointed out, what else is in there? How about Legionnaires Disease?
      - cm2187 9mo ago
        How is that different from the metal pipes through which drinking water goes through to reach your kitchen tap, some of which are over 100 years old if you live in the UK? The contact with metal shouldn't be the problem in itself. Legionnaires disease either, the water from the river isn't drinking water to start with and the water out of the datacenter wouldn't be drinking water either.
        jacquesm 9mo ago
        When you start of with 'a stupid question' and people then give you lots of reasonable answers and you persist with more such questions at some point you cause me to doubt if you were really asking your first question in good faith.

nonfamous 9mo ago

A lot of it gets converted to water vapor in the evaporative coolers, so it doesn't flow out -- it becomes humidity or clouds. The coolers do also produce waste water, but with all the minerals left behind after evaporation it's not suitable for drinking.

Ekaros 9mo ago

There are multiple ways. Closed loops, well not big deal you fill up and there is slight evaporation losses, but you could ship that in in tanker truck maybe once every few years. Next is open loop cooling using secondary loop. Take a river, lake or sea. Pump some water from it, pass through heat exchanger and pump back out. Manageable for most of the year. Worse version is pump ground water and return it to these. Depletes the ground water... And finally evaporative cooling. Which is boiling, but not at boiling point. Water goes to sky. No immediate return to local ground water or downstream the river... In this case you actually do in sense use up the water. Kinda like burning fossil fuels returns co2 to atmosphere. It will later turn to biomass, but that is a separate cycle.

progbits 9mo ago
The CO2 cycle is problematic because of timelines. We are releasing millions of years of CO2 accumulation. Rain is more of a location problem. The evaporated water returns as rain quickly, but maybe somewhere else, such as over ocean. And the aquifer compresses and loses water retention ability.

zvqcMMV6Zcr 9mo ago

> it comes out of the datacenter just a little warmer Exact values matter. Some power plants had been found dumping +10 C water into lakes/rivers, while they had permit only for +5, and it totally destroyed local ecosystem. And most efficient (in terms of money) is evaporation cooling, where at least part of water is "lost".