A thermal reservoir is a theoretical concept in thermodynamics used to model a body that can absorb or supply an unlimited amount of heat without changing its temperature.
Key features:
- Constant temperature: No matter how much heat is added or removed, the reservoir’s temperature remains unchanged.
- Infinite capacity: It can exchange heat without undergoing any internal energy changes.
- Used in theory: Real materials change temperature when heat is exchanged, but reservoirs are idealized to simplify analysis.
Why it matters:
Thermal reservoirs are essential for analyzing thermodynamic cycles like the Carnot or Otto cycle. They serve as reference points for heat transfer and allow scientists and engineers to define and measure efficiency and entropy changes without dealing with complex temperature fluctuations.