Thermodynamics and Efficiency 1690/1698 1803/1824 1784 1854/1862 Steam engine Definition Entropy Heat  Work Theory of efficiency

Evolution of concept: Heat  Work vacuum Steam-Water pump Thomas Savery 1650-1715 1698

Evolution of concept: Heat  Work Steam-Water pump Using a Piston Denis Papin 1647-1712 1690

Evolution of concept: Heat  Work The Proprietors of the Invention for Raising Water by Fire Thomas Newcomen 1664-1729 + (Thomas Savery) Efficiency: 2-5 %

Evolution of concept: Heat  Work James Watt 1736-1819 Steam engine Efficiency: 25 % 1784

Steam engines: Work and Heat  Is the amount of (useful) work limited?  Is there an alternative medium for steam? Thermodynamical model system: heat engine (useful) work Heat (flow) Sadi Carnot 1796-1832

Steam engines: Carnot cycle  Is the amount of (useful) work limited?  Is there an alternative medium for steam? (useful) work Heat (flow) Sadi Carnot 1796-1832 TH and TC separated: no internal losses Process steps: isotherms and adiabats  Idealized cycle: reversible process  Arbitrary medium: perfect gas

Steam engines: Carnot cycle  Is the amount of (useful) work limited?  Is there an alternative medium for steam? (useful) work Heat (flow) Sadi Carnot 1796-1832 Transformation of heat into work always involves losses (QC) 1824 Maximal efficiency depends on (TH -TC) TH and TC separated: no internal losses Process steps: isotherms and adiabats  Idealized cycle: reversible process  Arbitrary medium: perfect gas

Fundaments of thermodynamics First law: conservation of energy U Rudolf Clausius 1822-1888 Second law: transformations (processes) 1854 Äquivalenzwert der Verwandlung R. Clausius Philosophical Magazine, 12 (1856) p.81

Fundaments of thermodynamics First law: conservation of energy U Second law: transformations Sadi Carnot 1796-1832 (useful) work Heat (flow) Rudolf Clausius 1822-1888 Transformation of heat into work always involves losses (QC) 1850 Maximal efficiency depends on (TH -TC) 1865 For all reversible cyclic processes 1824

Fundaments of thermodynamics First law: conservation of energy U Second law: transformations Hermann von Helmholtz 1821-1894 Free (useful) work Helmholtz free energy

Fundaments of thermodynamics First law: conservation of energy U Second law: transformations Mechanical energy (work) Josiah Gibbs 1839-1903 Free (useful) non-mechanical work Gibbs free energy

Modern classical thermodynamics The entropy (spontaneously) always increases until thermodynamic equilibrium is reached

Modern classical thermodynamics ENTROPY ║ Heat + Temperature The total entropy (spontaneously) always increases until thermodynamic equilibrium is reached

Heat Q vs Work W and efficiency reversible Sadi Carnot (1796-1832) Carnot cycle

Heat Q vs Work W and efficiency reversible reversible Heat engine Carnot cycle

Heat Q vs Work W and efficiency reversible reversible reversible Heat engine Carnot cycle

Heat Q vs Work W and efficiency reversible reversible Heat engine Carnot cycle

Heat Q vs Work W and efficiency reversible Carnot cycle for a perfect gas and for a Carnot cycle for ANY MEDIUM Carnot cycle

Heat Q vs Work W and efficiency (no work) Clausius no work irreversible Heat flows spontaneously from a hot source to a cold sink

Heat Q vs Work W and efficiency (heat engine) Clausius Maximal work done by the system: for a reversible process

Heat Q vs Work W and efficiency (refridgerator) Not spontaneous Refridgeration needs work

Thermodynamics and the Perpetuum Mobile The Perpetuum Mobile of the first kind A perpetuum mobile of the first kind produces work without the input of energy. Villard de Honnecourt 1230 William Crookes 1873 Miles V. Sullivan 1945 Robert Boyle 1666

First law: conservation of energy U Thermodynamics and the Perpetuum Mobile The Perpetuum Mobile of the first kind A perpetuum mobile of the first kind produces work without the input of energy. First law: conservation of energy U

Thermodynamics and the Perpetuum Mobile The Perpetuum Mobile of the first kind

Thermodynamics and the Perpetuum Mobile The Perpetuum Mobile of the second kind A perpetuum mobile of the second kind is a machine capable of converting heat completely into (mechanical) work. Sadi Carnot 1824 James Watt 1784 Max Verstappen 2017

Thermodynamics and the Perpetuum Mobile The Perpetuum Mobile of the second kind A perpetuum mobile of the second kind is a machine capable of converting heat completely into (mechanical) work. Sadi Carnot 1824 Clausius 1865 Maximal efficiency Second law

First law: conservation of energy U Thermodynamics and the Perpetuum Mobile The Perpetuum Mobile of the third kind A perpetuum mobile of the third kind is a machine with an eternal motion and no energy input. fly wheel planets marbles Mechanical motions always imply friction  heat production Q First law: conservation of energy U

Thermodynamics and the Perpetuum Mobile The Perpetuum Mobile of the third kind A perpetuum mobile of the third kind is a machine with an eternal motion and no energy input. superconducting coil Kamerlingh Onnes 1911 MRI scanner

Thermodynamics and the Perpetuum Mobile The Perpetuum Mobile of the third kind A perpetuum mobile of the third kind is a machine with an eternal motion and no energy input. fly wheel with superconducting bearings floating superconductor Mechanical motions always imply friction  heat production Q First law: conservation of energy U