Microsoft's underwater data centre resurfaces after two years • Hacker News Board

Re: Microsoft's underwater data centre resurfaces after two years

#121

Post by NathanKP » Mon, Sep 14, 2020, 5:44 PM UTC

shawkinaw wrote: post #64

NathanKP wrote: post #21

Earlier quoted context omitted.

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 j…

> 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

It's not just the HVAC system itself, it is the supply chain to operate the HVAC as well. There is waste heat from the power transmission system to get power to the HVAC unit, waste heat from the power plant that produced the power, waste heat from the transport of raw materials to the power plant, increased global warming heat from the CO2 that the power plant produces while burning those raw materials, etc.

Obviously this can be mitigated if you are able to get renewable power from a nearby source like a geothermal plant, hydroelectric, or solar. But if you are using fossil fuel power from a long distance away, that means any unit of heat moved by an HVAC involved many units of heat production to ultimately move that unit of heat.

Re: Microsoft's underwater data centre resurfaces after two years

#122

Post by AlanSE » Mon, Sep 14, 2020, 5:45 PM UTC

ramon wrote: post #116

I don't like the idea since raising water temperatures affects life in the ocean like coral reefs.

This has been covered again and again in other comments. Thermal power plants dump heat into oceans today. The data center is much more efficient than a counterpart on land.

Ocean life and coral reefs are in danger due to temperature rise as a part of climate change. Energy efficiency helps reduce that temperature rise.

Re: Microsoft's underwater data centre resurfaces after two years

#123

Post by thefifthsetpin » Mon, Sep 14, 2020, 5:47 PM UTC

JumpCrisscross wrote: post #40

StavrosK wrote: post #37

Earlier quoted context omitted.

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.

> 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.

When you say "short term," how long are you talking about?

Re: Microsoft's underwater data centre resurfaces after two years

#124

Post by bilater » Mon, Sep 14, 2020, 5:47 PM UTC

jacquesm wrote: post #10

Why heat the oceans indirectly when you can just place the heatsource directly in them? Much less chance of losing precious ergs. Seriously though, what is the direct ecological impact of doing this at scale, would the local increase in temperature have an immediate effect on the life around it? If so how much of an impact? What about the effect on surface life and life in intermediary layers of the water? After all,…

Also keep in mind the majority of ocean life is close to the surface so this is also inherently less harmful than a sea side factory dumping heat and waste into the ocean.

Re: Microsoft's underwater data centre resurfaces after two years

#125

Post by rbanffy » Mon, Sep 14, 2020, 5:48 PM UTC

jacquesm wrote: post #10

Why heat the oceans indirectly when you can just place the heatsource directly in them? Much less chance of losing precious ergs. Seriously though, what is the direct ecological impact of doing this at scale, would the local increase in temperature have an immediate effect on the life around it? If so how much of an impact? What about the effect on surface life and life in intermediary layers of the water? After all,…

> a body this size radiating 10's of KW of heat

It's kind of literally a drop in the ocean, but I assume it'd be worth doing a bit of research about local disruptions if we intend to drop large deployments in shallow waters.

To shut down or significantly disturb ocean currents, we'd need a lot of these things.

Re: Microsoft's underwater data centre resurfaces after two years

#126

Post by mlyle » Mon, Sep 14, 2020, 5:49 PM UTC

gowld wrote: post #103

mlyle wrote: post #71

Earlier quoted context omitted.

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.

"Renewable" refers to energy, not just heat. The sun's energy is be used for other purposes than heat, thankfully. Growing a 100 trees and chopping them into lumber is less hot than growing 100 trees and burning them. If all the sun's energy were converted to heat (and not radiated away), we'd be in big trouble. That's what "carbon" pollution is all about -- Carbon dioxide is a greenhouse gas that traps heat. Reducin…

I think you missed the point of what I said. When we're talking about powering data centers with renewables, talking about sequestering carbon via lumber is rather orthogonal.

The point was, coarsely: using e.g. solar panels only changes the Earth's surface temperature to the extent it changes albedo. (Ignoring second-order effects of concentrating heat and associated effects on radiation, etc.)

Re: Microsoft's underwater data centre resurfaces after two years

#127

Post by rbanffy » Mon, Sep 14, 2020, 5:51 PM UTC

falcolas wrote: post #84

ChuckMcM wrote: post #63

Earlier quoted context omitted.

The scale is off. Things that affect local ecosystems are cooling multi-gigawatt nuclear reactors with nearby ocean water, you would be lucky if one of these drew a megawatt of power. That said, the physics are "heat is heat". If you put it into the air or you put it directly into the ocean the only way it leaves the planet is by black body radiation. As a result locally heating some seawater nearby has (on a global…

> the only way it leaves the planet is by black body radiation But, if you're heating the oceans, you're putting an entire other mass (the atmosphere) between yourself and space. So you're heating the water, the water is heating the atmosphere, and the atmosphere is radiating that into space. It's adding a step to the overall cooling process.

OTOH, if these are passively cooled, you are not dumping the waste heat of the HVAC systems, as well as the power user to keep them running.

Re: Microsoft's underwater data centre resurfaces after two years

#128

Post by trebel » Mon, Sep 14, 2020, 5:52 PM UTC

StavrosK wrote: post #37

NathanKP wrote: post #21

Earlier quoted context omitted.

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 j…

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.

Also consider cost (in terms of CO2, resource consumption, etc) of building and maintaining the renewable energy sources.

I don't know how this would compare between underwater datacenter, solar panels, wind.

Re: Microsoft's underwater data centre resurfaces after two years

#129

Post by nexuist » Mon, Sep 14, 2020, 5:53 PM UTC

RobRivera wrote: post #105

jacquesm wrote: post #10

Why heat the oceans indirectly when you can just place the heatsource directly in them? Much less chance of losing precious ergs. Seriously though, what is the direct ecological impact of doing this at scale, would the local increase in temperature have an immediate effect on the life around it? If so how much of an impact? What about the effect on surface life and life in intermediary layers of the water? After all,…

I'm sorry but this is such a 'goalpost' movement here that simply takes away a lot of context. The whole point of doing a dc underground is to reduce the hvac energy consumption which has a much larger ecological impact in terms of heat generated, power usage, potential greenhouse gas usage. The name of the game here is energy efficiency and conservation. Use less power by reducing power distribution loss at scale. W…

I don't think jacquesm is off the mark in asking these questions, especially:

> what is the direct ecological impact of doing this at scale

What is the impact on sea creatures if we put these giant heated cylinders in their territory? Is there any impact? I really doubt we have the answers yet.

> at scale

...also implies that there will be more than one. So if one heat cylinder doesn't do anything, what about 10? 100? 1000? 10,000? The cylinder pictured is really quite small, you'd need to make a ton of them or drop one mega-cylinder to compete with land based centers. And it's not like our current data centers are keeping up with computing demand; we are building more today and presumably will continue building them decades into the future.

So these are extremely important questions. We shouldn't dismiss this as a workable idea but we should also keep in mind that fucking up the ocean is a far more consequential action than fucking up some acres of land.

Re: Microsoft's underwater data centre resurfaces after two years

#130

Post by mlyle » Mon, Sep 14, 2020, 5:53 PM UTC

gpm wrote: post #114

mlyle wrote: post #66

Earlier quoted context omitted.

Another way to put this is it puts 130% of the source heat out into the environment.

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 fracti…

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.