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Carnot Engine Efficiency Calculator

Carnot Efficiency

Calculate maximum efficiency from hot and cold reservoir temperatures

Work Output

Calculate work output and heat rejected given heat input and temperatures

Formula

η = 1 - T_C/T_H | W = η·Q_H | Q_C = Q_H - W | COP_ref = T_C/(T_H - T_C) | COP_hp = T_H/(T_H - T_C)

Frequently Asked Questions

What is Carnot efficiency?
Carnot efficiency η = 1 - T_C/T_H is the maximum theoretical efficiency of any heat engine operating between two temperatures. No real engine can exceed this limit. T_H and T_C must be in absolute temperature (Kelvin).
Why can't a heat engine be 100% efficient?
By the second law of thermodynamics, some heat must always be rejected to the cold reservoir. 100% efficiency would require T_C = 0 K (absolute zero), which is unattainable. This is a fundamental limit, not a practical one.
What is COP for a refrigerator?
The Coefficient of Performance (COP) measures refrigerator or heat pump efficiency. For a Carnot refrigerator: COP = T_C/(T_H - T_C). For a heat pump: COP = T_H/(T_H - T_C). COP can exceed 1, unlike heat engine efficiency.

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