Technically it is inefficiency. The electricity should be doing computer things. Heat is wasted electricity. Just there's not much the data centre could do about it.
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.
And that’s ignoring that sound and photon emissions typically hit a wall or other physical surface and get converted back to heat.
It all ends up as heat in the end, just depends on where that heat is dumped and if you need to cool it or not. Most watts end up being even more than the theoretical heat per watt due to said cooling needs.
There is literally no way around the fact that every watt you burn for compute ends up as a watt of waste heat. The only factor you can control is how many units of compute you can achieve with that same watt.
That reminds me of a sci-fi book, Sundiver by David Brin, where a ship is exploring the sun by firing a "refrigerator laser" to somehow pump-away excess heat and balance on the thrust.
The energy of the universe is a pool of water a top a cliff. Water running off this cliff is used to do stuff (work), and the pool at the bottom is heat.
The "heat death of the universe" is referring to this water fall running dry, and all the energy being in this useless pool of "heat".
Is it impossible to convert heat into other forms of energy without "consuming" materials like in the case of steam, geothermal or even the ones that need a cold body to utilize thermoelectric effect.
[1]: Technically the movement itself is heat, the objects don't contain heat, rather they contain internal energy, but the two get mixed up more often than not.
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 building massive space structures/projects, but then lets the waste heat just pour out into the universe in such insane quantities that we could see it tens/hundreds of light years away? What a waste. Why wouldn't they recover that heat and make use of it instead? And repeat the recovering until the final waste output is too small to bother recovering, at which point we would no longer be able to detect it.
There is no way to get rid of heat. It has to go somewhere; otherwise, the temperature of the system will increase without bound.
Or if you magically beam 100% of the captured energy somewhere else, now that place gets to deal with shedding the heat from however many 1e26W+ of power were consumed. God help the poor planet you aim that ray of death at.
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.
"British reversible computing startup Vaire has demonstrated an adiabatic reversible computing system with net energy recovery"
https://www.eetimes.com/vaire-demos-energy-recovery-with-rev...
Short introduction video to reversible computing:
Thanks for posting. Pretty cool.
Yes it ends up as heat, but with some forethought, it could be used to eg heat people's homes rather than as waste.
In really, it’s not convenient to move all waste heat to where it’s more needed.
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
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.
Certain chemical reaction endotermic reaction require energy to start. This energy is absorbed to generate molecular bond.
Also in the generation and absorption of high energy radiation there are non-thermal processes that can transfer energy.
Even something like bending a metal bar is not 100% a thermal process.
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.
And it only cost 0.006 rain forests!
For example, kinda wasteful to cook eggs with new electrons when you could use the computer heat to help you denature those proteins. Or just put the heat in human living spaces.
(Putting aside how practical that actually is... Which it isn't)
It's that computation requires electricity. And almost all of the heat in bitcoin mining comes from computation, technically changing transistor state.