Search results
Results from the WOW.Com Content Network
Since a Carnot heat engine is a reversible heat engine, and all reversible heat engines operate with the same efficiency between the same reservoirs, we have the first part of Carnot's theorem: No irreversible heat engine is more efficient than a Carnot heat engine operating between the same two thermal reservoirs.
A Carnot cycle is an ideal thermodynamic cycle proposed by French physicist Sadi Carnot in 1824 and expanded upon by others in the 1830s and 1840s. By Carnot's theorem, it provides an upper limit on the efficiency of any classical thermodynamic engine during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference through ...
Axial cross section of Carnot's heat engine. In this diagram, abgh is a cylindrical vessel, cd is a movable piston, and A and B are constant–temperature bodies. The vessel may be placed in contact with either body or removed from both (as it is here). [1] A Carnot heat engine [2] is a theoretical heat engine that operates on the Carnot cycle.
Q H = W + Q C = heat exchanged with the hot reservoir. η = W / (Q C + Q H) = thermal efficiency of the cycle If the cycle moves in a clockwise sense, then it is a heat engine that outputs work; if the cycle moves in a counterclockwise sense, it is a heat pump that takes in work and moves heat Q H from the cold reservoir to the hot reservoir.
Thermodynamic diagrams usually show a net of five different lines: isobars = lines of constant pressure; isotherms = lines of constant temperature; dry adiabats = lines of constant potential temperature representing the temperature of a rising parcel of dry air
Carnot's theorem applies to thermodynamic cycles, where thermal energy is converted to mechanical work. Devices that convert a fuel's chemical energy directly into electrical work, such as fuel cells , can exceed the Carnot efficiency.
The first and second law of thermodynamics are the most fundamental equations of thermodynamics. They may be combined into what is known as fundamental thermodynamic relation which describes all of the changes of thermodynamic state functions of a system of uniform temperature and pressure.
Carnot's principle was recognized by Carnot at a time when the caloric theory represented the dominant understanding of the nature of heat, before the recognition of the first law of thermodynamics, and before the mathematical expression of the concept of entropy. Interpreted in the light of the first law, Carnot's analysis is physically ...