1. What is Carnot Efficiency?

Carnot efficiency represents the maximum possible efficiency that a heat engine operating between two reservoirs can achieve, according to the second law of thermodynamics. It establishes an upper limit for the conversion of heat energy into work.

2. How Does the Calculator Work?

The calculator uses the Carnot efficiency formula:

Where:

• \( \eta \) — Carnot efficiency (dimensionless)
• \( T_c \) — Absolute temperature of cold reservoir (Kelvin)
• \( T_h \) — Absolute temperature of hot reservoir (Kelvin)

Explanation: The efficiency depends only on the temperature difference between the hot and cold reservoirs. Higher temperature differences yield higher possible efficiencies.

3. Importance of Carnot Efficiency

Details: Carnot efficiency is crucial in thermodynamics as it sets the theoretical maximum for any heat engine's efficiency. It helps engineers evaluate how close real engines come to ideal performance.

4. Using the Calculator

Tips: Enter both temperatures in Kelvin. The hot reservoir temperature must be greater than the cold reservoir temperature. The result will be displayed as a percentage.

5. Frequently Asked Questions (FAQ)

Q1: Why can't real engines reach Carnot efficiency?
A: Real engines have irreversibilities like friction, heat loss, and finite temperature differences that prevent them from achieving the theoretical maximum.

Q2: What are typical Carnot efficiency values?
A: For steam turbines (T_h≈800K, T_c≈300K), η≈62.5%. For car engines (T_h≈2000K, T_c≈300K), η≈85%.

Q3: Can efficiency be 100%?
A: Only if T_c=0K (absolute zero), which is physically impossible to achieve.

Q4: Does Carnot efficiency apply to refrigerators?
A: Yes, but in reverse - the coefficient of performance (COP) is limited by the temperature difference.

Q5: Why use Kelvin instead of Celsius?
A: The formula requires absolute temperatures because efficiency depends on the ratio of temperatures, not their difference.