10 ms·
Let's be precise. When we say "convert heat to power", what we mean is actually "if we have some energy flowing from a heat source to a heat sink, we can extrac
by semi-extrinsic 3y ago
Let's be precise. When we say "convert heat to power", what we mean is actually "if we have some energy flowing from a heat source to a heat sink, we can extract a percentage of that energy as useful work, like turning a steam turbine to produce electricity".
Carnot proved in 1824 that the maximum theoretical efficiency is purely a function of the hot and cold temperature (in Kelvin):
Eff = (T_hot - T_cold)/T_hot
So for instance a thermoelectric generator operating between 25 °C and 5 °C has a maximum efficiency of
Eff = (298 - 278) / 298 = 6.7%
- someplaceguy 3y ago> So for instance a thermoelectric generator operating between 25 °C and 5 °C has a maximum efficiency of > Eff = (298 - 278) / 298 = 6.7% Does that mean a thermoelectric generator operating at a minimum of 0K has a maximum efficiency of Eff = (N - 0) / N = 100%?
- 11101010001100 3y agoOr just (2*N-N)/N.
- someplaceguy 3y agoAccording to the formula you'd have to divide by 2*N.
- 11101010001100 3y agomy mistake!
- tullianus 3y agoYes, although in practice you will have issues sinking heat at 0K without using additional energy to do so, since that's below the radiation sink temperature of space (~2.73K).