Thermo dynamics An Engineering Approach Third Edition Yunus A. Çengel Michael A. Boles

1. Thermodynamics An Engineering Approach Third Edition Yunus A. Çengel Michael A. Boles WCB/McGraw-Hill © The McGraw-Hill Companies, Inc.,1998

2. 1 CHAPTER BasicConcepts ofThermodynamics

3. The human body Air-conditioningsystems Airplanes Car radiators Power plants Refrigeration systems 1-1 Applications of Thermodynamics

4. (Fig. 1-13) 1-2 Crossing Closed-System Boundries Energy, not mass, crosses closed-system boundries

5. 1-3 Closed System with Moving Boundry

6. 1-4 Crossing Control Volume Boundaries Mass and Energy Cross Control Volume Boundaries

7. (Fig. 1-19) 1-5 System’s Internal Energy System’s Internal Energy = Sum of Microscopic Energies

8. (Fig. 1-30) 1-6 Quasi-Equilibrium, Work-Producing Devices Quasi-Equilibrium, Work-Producing Devices Deliver the Most Work

9. (Fig. 1-31) 1-7 Compressed Process P-V Diagram

10. (Fig. 1-36) 1-8 Absolute, Gage, and Vacuum Pressures

11. 1-9 The Basic Manometer

12. (Fig. 1-48) 1-10 Temperature Scales Comparison

13. (Fig. 1-52) 1-11 Many Ways to Supply the Same Energy Ways to supply a room with energy equalling a 300-W electric resistance heater

14. (Fig. 1-53) 1-12 Bomb Calorimeter Used to Determine Energy Content of Food

15. 1-13 Chapter Summary • Thermodynamics is the science that primarily deals with energy.

16. 1-14 Chapter Summary • The first law of thermodynamics is simply an expression of the conservation of energy principle, and it asserts that energy is a thermodynamic property. • The second law of thermodynamics asserts that energy has quality as well as quantity, and actual processes occur in the direction of decreasing quality of energy.

17. 1-15 Chapter Summary • A system of fixed mass is called a closed system, or control mass, and a system that involves mass transfer across its boundaries is called an open system, or control volume.

18. 1-16 Chapter Summary • The mass-dependent properties of a system are called extensive properties and the others, intensive properties. Density is mass per unit volume, and specific volume is volume per unit mass.

19. 1-17 Chapter Summary • The sum of all forms of energy of a system is called total energy, which is considered to consist of internal, kinetic, and potential energies. Internal energy represents the molecular energy of a system and may exist in sensible, latent, chemical, and nuclear forms.

20. 1-18 Chapter Summary • A system is said to be in thermodynamic equilibrium if it maintains thermal, mechanical, phase, and chemical equilibrium.

21. 1-19 Chapter Summary • Any change from one state to another is called a process. • A process with identical end states is called a cycle.

22. 1-20 Chapter Summary • During a quasi-static or quasi-equilibrium process, the system remains practically in equilibrium at all times.

23. 1-21 Chapter Summary • The state of a simple, compressible system is completely specified by two independent, intensive properties.

24. 1-22 Chapter Summary • Force per unit area is called pressure, and its unit is the pascal. The absolute, gage, and vacuum pressures are related by

25. 1-23 Chapter Summary • Small to moderate pressure differences are measured by a manometer, and a differential fluid column of height h corresponds to a pressure difference of where  is the fluid density and g is the local gravitational acceleration.

26. 1-24 Chapter Summary • The atmospheric pressure is measured by a barometer and is determined from where h is the height of the liquid column above the free surface.

27. 1-25 Chapter Summary • The zeroth law of thermodynamics states that two bodies are in thermal equilibrium if both have the same temperature reading even if they are not in contact.

28. 1-26 Chapter Summary • The temperature scales used in the SI and the English system today are the Celsius scale and the Fahrenheit scale, respectively.

29. 1-27 Chapter Summary • The absolute temperature scale in the SI is the Kelvin scale, which is related to the Celsius scale by

30. 1-28 Chapter Summary • In the English system, the absolute temperature scale is the Rankine scale, which is related to the Fahrenheit scale by

31. 1-29 Chapter Summary • The magnitudes of each division of 1 K and 1 0C are identical, and so are the magnitude of each division of 1 R and 10F. Therefore,and

32. 1-30 Chapter Summary • An important application area of thermodynamics is the biological system. Most diets are based on the simple energy balance: the net energy gained by a person in the form of fat is equal to the difference between the energy intake from food and the energy expended by exercise.