Re:Bitcoin mining heats homes for free in Siberia [video]
by jaakl on Sunday November 05, 2017 @01:42PM
(#15630834)
Heat pump takes energy from two sources, power grid and outside environment: air, landmass or water (there are even air+land models etc). Their energy output is always less than sum of sources, so their efficency is never over 100%. But as the ambient land/air/water heat is generally ”free” then we seem to get 3-500% economy. I have never even seen the technical/physical efficiency numbers for heat pumps as consumers do not care about this.
But that's the performance. Efficiency is usually a measure of how good the performance is.
In this case there's a practical reason not to call it efficiency, because there is a well understood maximum performance which is the Carnot limit, so for practical purposes (to avoid confusion) PumpedHeat/Power is called "coefficient of performance"and CarnotLimit/PumpedHeat is called "efficiency", and it has the usual properties that it cannot exceed 100% and it measures how well your system works in a more or less absolute sense.