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

2. Evolution of concept: Heat  Work
vacuum
Steam-Water pump
Thomas Savery
1698

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

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

5. Evolution of concept: Heat  Work
James Watt
Steam engine
Efficiency: 25 %
1784

6. 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

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

8. Steam engines: Carnot cycle
 Is the amount of (useful) work limited?
 Is there an alternative medium for steam?
(useful)
work
Heat
(flow)
Sadi Carnot
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

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

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

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

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

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

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

16. Heat Q vs Work W and efficiency
reversible
Sadi Carnot ( )
Carnot cycle

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

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

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

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

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

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

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

25. 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

26. 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

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

28. 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

29. 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

30. 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

31. 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

32. 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