Calculate Carnot Efficiency

Calculator for the Carnot efficiency from the temperature ratio of the process. The Carnot efficiency or Carnot factor describes the maximum amount of energy that can be used when converting heat into motion. This depends on the lowest temperature (cold, T_k) and the highest temperature (hot, T_h) in the process. This process can be combustion, as in the internal combustion engine. The fuel in the cylinder is at its lowest temperature when it is at its largest volume and at its highest temperature at its smallest volume when it is most compressed.
The Carnot efficiency η_c is calculated with the formula η_c = ( 1 - T_k/T_h ) * 100%
The temperature can be specified in degrees Celsius, Fahrenheit or in Kelvin, calculations are made in Kelvin. Please enter one cold and one hot temperature.

	cold	hot
°C
°F
K

Carnot efficiency

η_c =	%
Loss:	%

Example: the temperature range of the fuel in the combustion engine is between 1000 and 2500 degrees Celsius. So the Carnot efficiency is at 54 percent, the loss at 46 percent. This is the theoretical upper limit for the efficiency of an internal combustion engine. In practice, other factors also reduce the efficiency, especially friction, so that it is below 30 percent.

For one hundred percent Carnot efficiency, you would need either a lowest temperature of zero Kelvin, which is not possible, or an infinite maximum temperature, which of course is also not possible. Increasing the temperature range would increase the Carnot efficiency, but poses additional problems as very high temperatures cause greater damage and require special materials and cooling during combustion is technically difficult. An internal combustion engine is therefore far inferior to an electric motor, which is not subject to Carnot efficiency. An electric motor can achieve an efficiency of well over 90 percent.