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An HVAC system above ground would generate far more heat. The advantage of sinking the data center would appear to be that it can function with passive cooling

An HVAC system above ground would generate far more heat. The advantage of sinking the data center would appear to be that it can function with passive cooling from the surrounding water only, no HVAC. This means less electricity consumption (meaning less energy generation required, and fewer resulting greenhouse gasses). And HVAC systems create far more waste heat than they do cooling, so this passive cooling will just be moving the source heat to the water, not dumping extra waste heat as well. Overall an underwater data center should generate far less heat overall than an aboveground one.

Shivetya 6y ago
Well they why not create artificial bodies of water and just keep our data centers there? How much water is sufficient for the cooling cycle to not require additional energy? How much water will need to be added to such pools to deal with evaporation? I think on a smaller scale test with an artificial pool would provide some solid answers. We could even put solar panels across the surface to limit wind and solar evaporation effects
- lawlessone 6y ago
  You'd have to pump loads of water for it then? to fill the pool and replace what is lost to evaporation. "I think on a smaller scale test with an artificial pool would provide some solid answers. We could even put solar panels across the surface to limit wind and solar evaporation effects " If it's artificial pool you'd need evaporation to cool it.
  - Godel_unicode 6y ago
    Do you not consider lake Powell to be an artificial body of water?
    - lawlessone 6y ago
      never heard of it until now
StavrosK 6y ago
The issue is CO2, though, not heat per se. Yes, the two are correlated, but if you use renewables to power your things, it doesn't really matter how much heat you generate. Please correct me if I'm wrong.
- JumpCrisscross 6y ago
  > it doesn't really matter how much heat you generate Doesn’t matter is strong. It won’t in the short term. But as we continue increasing our energy use as a species, the simple thermal problem of waste-heat management will certainly surface.
  - StavrosK 6y ago
    Sure, where "doesn't matter" read "is way way less important than CO2 emissions".
  - mlyle 6y ago
    If you use renewables, you're using heat that is already around on the planet. As long as you don't change planetary albedo, equilibrium temperature is the same. Of course, heating water locally, etc, can cause its own environmental impacts.
    - bluGill 6y ago
      Not necessarily - if (I think this is true but am not able to prove it) the earth is on a slight negative carbon slope, and renewables reduce that slope we are still making an impact on long term temperature.
    - ithkuil 6y ago
      this! another way to look at it: your solar panels are temporarily "stealing" heat generated by sun rays hitting a surface of equivalent color. When you use electricity to do some work, it will be turned back to heat. so if you want to be 100% "heat neutral", all you have to do is to ensure that for every square meter of solar panels you also paint an proportionate area with a color that reflects the right amount of sunlight to compensate the difference between the color of the solar panel and the area that was there before you installed the solar panel. If you think that's silly (and rightfully so), then perhaps that can sharpen your intuition on how insignificant is the total amount of heat produced by our devices (even if cumulatively they are a big looking number); the total amount of radiation that comes from the sun down to earth is staggering.
uluyol 6y ago
I think the question is what is the local impact of the temperature increase? It would be good to know if it harms certain types of ecosystems ahead of time rather than after the fact. It's also possible that a direct increase in ocean temperature has undesirable knock-on effects that don't take place if you operate on land.
- bearjaws 6y ago
  I believe it would be less impactful than many power plants that vent their heat into the ocean. There are many studies, mainly around marine life (phytoplankton, manatees, other endangered species). These systems probably produce similar heat output into the water. https://assets.nrdc.org/sites/default/files/power-plant-cooling-IB.pdf https://assets.nrdc.org/sites/default/files/power-plant-cool... https://www.sciencedirect.com/science/article/abs/pii/S0025326X18303825 https://www.sciencedirect.com/science/article/abs/pii/S00253... https://res.mdpi.com/d_attachment/water/water-11-02577/article_deploy/water-11-02577-v2.pdf https://res.mdpi.com/d_attachment/water/water-11-02577/artic...
- kamel3d 6y ago
  Well this was all an experiment itself and I am sure the ecological factor is being taken in consideration
shawkinaw 6y ago
> And HVAC systems create far more waste heat than they do cooling, so this passive cooling will just be moving the source heat to the water, not dumping extra waste heat as well. Where do you get that idea? A typical EER 12 air conditioner will move 3.5x the heat energy that it consumes (COP = 3.5) [0]. [0] https://www.engineeringtoolbox.com/cop-eer-d_409.html https://www.engineeringtoolbox.com/cop-eer-d_409.html
- mlyle 6y ago
  Another way to put this is it puts 130% of the source heat out into the environment.
  - gpm 6y ago
    No, it's way worse than that. At the location of the hvac it puts 130% of the source heat into the environment. But 30% of that heat put into the environment came from electricity generated in a power plant. Power plants are typically less than 50% efficient, so it put's out as much heat into the environment at the source of the electricity. Bumping the value to 160% (130% + 30%). However waste heat is a small fraction of the heating that electricity generation produces. Very roughly 10 times as much heat is trapped via the CO2 released than heat is released by the power plant. Bumping that value up to 460% (160% + 30% * 10). I.e. 4.6 units of heat are put into the environment for every unit of heat removed from a closed system. (Obviously the details of this depend dramatically on the environment. Heat pump efficiency depends on the degree of temperature gradient, CO2 release and power plant efficiency depends dramatically on where the power is coming from, which changes with where you are located.)
    - mlyle 6y ago
      Fair points. IMO, the 460% metric is a bit of a wacky number, though, because of not counting the carbon and efficiency involved in the original 100%. Assuming the 100% comes from the same power source, it's still only 25-30% "worse". Also I think you're a bit pessimistic about modern power plant efficiency-- combined cycle plants do better than 50%, and that's before we're considering any benefit from renewables.
PopeDotNinja 6y ago
You could have a solar powered HVAC system that captures the condensed water, and then submerge the thing you’re trying to cool in that water! P.S. am not HVAC wizard.
- bhhaskin 6y ago
  The issue is the HVAC system itself creates a lot of heat. It normally doesn't matter in a traditional system as the heat is generated out side the areas being cooled.
mensetmanusman 6y ago
saying ‘at scale’ is being unclear, because it seems to be implying that we should consider what would happen if we put every data center today underwater in the same spot, which is what no one is thinking of doing...

Shivetya 6y ago

Well they why not create artificial bodies of water and just keep our data centers there? How much water is sufficient for the cooling cycle to not require additional energy? How much water will need to be added to such pools to deal with evaporation? I think on a smaller scale test with an artificial pool would provide some solid answers. We could even put solar panels across the surface to limit wind and solar evaporation effects

lawlessone 6y ago
You'd have to pump loads of water for it then? to fill the pool and replace what is lost to evaporation. "I think on a smaller scale test with an artificial pool would provide some solid answers. We could even put solar panels across the surface to limit wind and solar evaporation effects " If it's artificial pool you'd need evaporation to cool it.
- Godel_unicode 6y ago
  Do you not consider lake Powell to be an artificial body of water?
  - lawlessone 6y ago
    never heard of it until now

StavrosK 6y ago

The issue is CO2, though, not heat per se. Yes, the two are correlated, but if you use renewables to power your things, it doesn't really matter how much heat you generate. Please correct me if I'm wrong.

JumpCrisscross 6y ago
> it doesn't really matter how much heat you generate Doesn’t matter is strong. It won’t in the short term. But as we continue increasing our energy use as a species, the simple thermal problem of waste-heat management will certainly surface.
- StavrosK 6y ago
  Sure, where "doesn't matter" read "is way way less important than CO2 emissions".
- mlyle 6y ago
  If you use renewables, you're using heat that is already around on the planet. As long as you don't change planetary albedo, equilibrium temperature is the same. Of course, heating water locally, etc, can cause its own environmental impacts.
  - bluGill 6y ago
    Not necessarily - if (I think this is true but am not able to prove it) the earth is on a slight negative carbon slope, and renewables reduce that slope we are still making an impact on long term temperature.
  - ithkuil 6y ago
    this! another way to look at it: your solar panels are temporarily "stealing" heat generated by sun rays hitting a surface of equivalent color. When you use electricity to do some work, it will be turned back to heat. so if you want to be 100% "heat neutral", all you have to do is to ensure that for every square meter of solar panels you also paint an proportionate area with a color that reflects the right amount of sunlight to compensate the difference between the color of the solar panel and the area that was there before you installed the solar panel. If you think that's silly (and rightfully so), then perhaps that can sharpen your intuition on how insignificant is the total amount of heat produced by our devices (even if cumulatively they are a big looking number); the total amount of radiation that comes from the sun down to earth is staggering.

uluyol 6y ago

I think the question is what is the local impact of the temperature increase? It would be good to know if it harms certain types of ecosystems ahead of time rather than after the fact. It's also possible that a direct increase in ocean temperature has undesirable knock-on effects that don't take place if you operate on land.

bearjaws 6y ago
I believe it would be less impactful than many power plants that vent their heat into the ocean. There are many studies, mainly around marine life (phytoplankton, manatees, other endangered species). These systems probably produce similar heat output into the water. https://assets.nrdc.org/sites/default/files/power-plant-cooling-IB.pdf https://assets.nrdc.org/sites/default/files/power-plant-cool... https://www.sciencedirect.com/science/article/abs/pii/S0025326X18303825 https://www.sciencedirect.com/science/article/abs/pii/S00253... https://res.mdpi.com/d_attachment/water/water-11-02577/article_deploy/water-11-02577-v2.pdf https://res.mdpi.com/d_attachment/water/water-11-02577/artic...
kamel3d 6y ago
Well this was all an experiment itself and I am sure the ecological factor is being taken in consideration

shawkinaw 6y ago

> And HVAC systems create far more waste heat than they do cooling, so this passive cooling will just be moving the source heat to the water, not dumping extra waste heat as well. Where do you get that idea? A typical EER 12 air conditioner will move 3.5x the heat energy that it consumes (COP = 3.5) [0]. [0] https://www.engineeringtoolbox.com/cop-eer-d_409.html https://www.engineeringtoolbox.com/cop-eer-d_409.html

mlyle 6y ago
Another way to put this is it puts 130% of the source heat out into the environment.
- gpm 6y ago
  No, it's way worse than that. At the location of the hvac it puts 130% of the source heat into the environment. But 30% of that heat put into the environment came from electricity generated in a power plant. Power plants are typically less than 50% efficient, so it put's out as much heat into the environment at the source of the electricity. Bumping the value to 160% (130% + 30%). However waste heat is a small fraction of the heating that electricity generation produces. Very roughly 10 times as much heat is trapped via the CO2 released than heat is released by the power plant. Bumping that value up to 460% (160% + 30% * 10). I.e. 4.6 units of heat are put into the environment for every unit of heat removed from a closed system. (Obviously the details of this depend dramatically on the environment. Heat pump efficiency depends on the degree of temperature gradient, CO2 release and power plant efficiency depends dramatically on where the power is coming from, which changes with where you are located.)
  - mlyle 6y ago
    Fair points. IMO, the 460% metric is a bit of a wacky number, though, because of not counting the carbon and efficiency involved in the original 100%. Assuming the 100% comes from the same power source, it's still only 25-30% "worse". Also I think you're a bit pessimistic about modern power plant efficiency-- combined cycle plants do better than 50%, and that's before we're considering any benefit from renewables.

PopeDotNinja 6y ago

You could have a solar powered HVAC system that captures the condensed water, and then submerge the thing you’re trying to cool in that water! P.S. am not HVAC wizard.

bhhaskin 6y ago
The issue is the HVAC system itself creates a lot of heat. It normally doesn't matter in a traditional system as the heat is generated out side the areas being cooled.

mensetmanusman 6y ago

saying ‘at scale’ is being unclear, because it seems to be implying that we should consider what would happen if we put every data center today underwater in the same spot, which is what no one is thinking of doing...