141–150 of 170 posts
This life is needlessly absurd. Why does this even exist? And yes, I get what mining is and I get what the blockchain does. I’m saying that proof of work is absurd.
Those datacenters are the moai of our time; if you step back, it's interesting to watch.
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Even if the computer does perfectly-efficient computer things with every Joule, every single one of those Joules ends up as one Joule of waste heat. If you pull 100W of power out of an electric socket, you are heating your environment at 100W of power completely independent of what you use that electricity for.
Theoretically, if your computation is energy efficient, you won't need any electricity at all since the real computation costs zero energy.
I say "ordinary computers" because other comments mentioned "reversible computers" for which this limit doesn't apply.
According to the linked wikipedia page, this theoretical limit is around a billion times smaller than current computers use for an operation, so you may call me pedantic.
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You can multiply your own power bill by 300,000 if money is a more relatable unit.
These discussions often turn into a ‘is this per hour? Per year?’ Discussion, which I find irritating. And now I’m that guy. Is this a daily usage thing? I test based on my home usage and the numbers seem way out. I use about 25kWh per day.
Last month it was 7. And we’re in the winter. Over the summer is more like 5.
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Seriously, the only way I would accept Bitcoin mining is as a winter heating source that pays for itself. Why can't people sell those?
The economics of bitcoin mining dictate that the work must have no other utility. If you increase its profitability by using it for auxiliary winter heating, then more people will mine bitcoin until there is an oversupply of heating and we return to the current equilibrium amount of "wasted" heat.
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There was a startup in EU which explicitly sold heat from crypto mining to the local energy provider. IIRC it was also here on hacker news some time ago.
Qarnot maybe
Earlier quoted context omitted.
Even if the computer does perfectly-efficient computer things with every Joule, every single one of those Joules ends up as one Joule of waste heat. If you pull 100W of power out of an electric socket, you are heating your environment at 100W of power completely independent of what you use that electricity for.
This violates energy conservation principles. Some power will be "wasted" into heat, some other will be used for some other work.
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While spinning, the blades store a miniscule amount of kinetic energy. After removing power even that small amount ends up as heat through friction ( both in the bearing but mostly in the air turbulence). And the blades end up in the same zero energy state: sitting still. So it is correct that a 100% "end up" as heat
Most of that energy gets transfered to the air that's being moved by the blades, and who knows what that air does eventually. And we're not even talking about the plant growing light that might be sitting in my room near my house plants literally creating new life from electricity.
We do know what that air does eventually. Given no further inputs of energy, it swirls around generating friction, raising its temperature (heat!) as the currents slow down to nearly nothing.
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> wasted energy that in theory could be turned into useful work Even if turned into useful work, the end result of that work is still ultimately heat.
Right, but if it's noticeably hotter than the environment, then that temperature difference could be used to drive a heat engine and get some more useful work. So the knee-jerk response "omg, we see the heat from space? it's gotta be wasteful!" is kind of correct, in theory.
Earlier quoted context omitted.
Even if the computer does perfectly-efficient computer things with every Joule, every single one of those Joules ends up as one Joule of waste heat. If you pull 100W of power out of an electric socket, you are heating your environment at 100W of power completely independent of what you use that electricity for.
I read it as the inefficient part isn't the compute efficiency, the inefficient part is dumping all the resulting heat into the environment without capturing it and using it in some way to generate electricity or do work. On a related/side note, when there's talk about seti and dyson spheres, and detecting them via infrared waste heat, I also don't understand that. Such an alien civilization is seemingly capable of b…
There is no other alternative! If I build a perfect Dyson sphere and capture the energy output of a star, all of that energy will become heat. The average surface temperature of my Dyson sphere will be (IIRC) the ratio of the surface area of the sphere to that of the contained star, multiplied by the star's effective surface temperature.
"Recovering heat and making use of it" requires a heat differential. You need a cold side and a hot side to use energy. Using that energy causes the cold side to heat and the hot side to cool, until they reach equilibrium. The further the difference, the more usable work you can do. The closer the two sides are, the less work you can do.
Someone else here said it best: waste heat is the graveyard of energy. Once you have used energy, it will become high-entropy, low-grade, diffuse heat which is difficult-to-impossible to extract further work from.