Find the maximum thermodynamic efficiency

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SUMMARY

The maximum thermodynamic efficiency of an engine operating between 250°C and 25°C can be calculated using the formula Ec = 1 - Tc/Th. The correct approach is to convert temperatures to Kelvin before performing calculations, which avoids errors associated with using Celsius. The calculations yield an efficiency of 43% when using Kelvin, while using Celsius incorrectly suggests 90%. Adhering to the use of Kelvin is essential for accurate thermodynamic analysis.

PREREQUISITES
  • Understanding of thermodynamic efficiency concepts
  • Familiarity with Carnot's Theorem
  • Knowledge of temperature conversion between Celsius and Kelvin
  • Basic proficiency in applying thermodynamic equations
NEXT STEPS
  • Study the derivation and implications of Carnot's Theorem in thermodynamics
  • Learn about the application of the Carnot cycle in real-world engines
  • Explore advanced thermodynamic efficiency calculations using different working fluids
  • Investigate the impact of temperature gradients on engine performance
USEFUL FOR

Students studying thermodynamics, engineers designing thermal systems, and anyone interested in optimizing engine efficiency.

kelvin56484984
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Homework Statement


If an engine operates between 250°C and 25°C, what is its maximum thermodynamic efficiency?

Homework Equations


Ec=1-Tc/Th

The Attempt at a Solution


1-25/250
=90%
or
1-(25+273)/(250+273)
=43%

In this question,which one should I use K or ºC ?
thank you
 
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kelvin56484984 said:

Homework Statement


If an engine operates between 250°C and 25°C, what is its maximum thermodynamic efficiency?

Homework Equations


Ec=1-Tc/Th

The Attempt at a Solution


1-25/250
=90%
or
1-(25+273)/(250+273)
=43%

In this question,which one should I use K or ºC ?
thank you
What does Carnot's Theorem say about this?

https://en.wikipedia.org/wiki/Carnot's_theorem_(thermodynamics)
 
If you always use Kelvin you will avoid ever worrying about this again. Always just convert to Kelvin before doing anything else and you won't go wrong. The only time to use Celsius in thermodynamics or heat transfer is if the question want the answer in Celsisus - in that case convert to Celsius at the very last step after using Kelvin for calculations.
 

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