Perfect engine

Definition

A perfect engine is a hypothetical thermodynamic engine that operates with 100% efficiency, converting all absorbed heat into work without any waste energy or entropy increase. Such an engine violates the Second Law of Thermodynamics and cannot exist in reality.

5 Must Know Facts For Your Next Test

1. A perfect engine would defy the Kelvin-Planck statement of the Second Law of Thermodynamics.
2. It implies zero entropy change during its cycle, which is impossible for real processes.
3. No real engine can achieve 100% efficiency due to inevitable losses like friction and heat dissipation.
4. The concept of a perfect engine helps illustrate why perpetual motion machines are unfeasible.
5. Understanding the limitations imposed by real engines allows better design and optimization within those constraints.

Review Questions

• Why can't a perfect engine exist according to the Second Law of Thermodynamics?
• What is the significance of entropy in ruling out the possibility of a perfect engine?
• How does the concept of a perfect engine help in understanding real-world thermodynamic systems?

Related terms

Second Law of Thermodynamics:

States that total entropy always increases over time for an isolated system, and it is impossible to convert all heat into work without some energy loss.

Carnot Engine: A theoretical model that defines the maximum possible efficiency any heat engine can achieve, operating between two temperatures.

Entropy:

A measure of disorder or randomness in a system; it quantifies irreversible energy dispersal at a given temperature.