Find the Carnot efficiency η = 1 − Tc / Th of a reversible heat engine, with both temperatures in kelvin.
| η | – |
| η (%) | – |
Use this calculator for the theoretical upper bound on a heat engine between two thermal reservoirs. No engine working between those baths can beat η = 1 − Tc / Th. Both temperatures must be absolute kelvin, not Celsius, and the hot side must be warmer than the cold side.
600 K and 300 K give η = 0.5, or 50%. Real engines sit well below this limit because of friction, heat leaks, and finite-time heat transfer. Convert Celsius to kelvin by adding 273.15 before you enter the values.
Th (K): Hot-reservoir temperature in kelvin, greater than Tc.
Tc (K): Cold-reservoir temperature in kelvin, greater than 0 and less than Th.
η: Efficiency as a fraction between 0 and 1.
η (%): The same efficiency as a percentage.
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