1. LECTURES IN THERMODYNAMICS Claus Borgnakke CHAPTER 1
For the 8th Edition of:
Fundamentals of Thermodynamics
Claus Borgnakke, Richard Sonntag
John Wiley & Sons, 2013

2. Chapter 1 Introduction to Thermodynamics
Thermodynamic System and Control Volume
Properties, Processes and Cycles
Units
Specific Volume and Density
Pressure
Energy and Temperature

3. Introduction to Thermodynamics
Theory about energy, its conversion and its effect on substances and devices. Subjects: Thermal systems, devices, components Examples: Steam Power Plant, Air conditioner (A/C) unit, Heater, Boiler, Steam generator, Refrigerator, Engine, Pump, Nozzle, … Subjects: Behavior and Properties of pure substances Examples: When is water (H2O) a solid (ice), liquid or vapor (gas) When air is compressed how much smaller does it become? How much energy is needed to bring cold water to a boil? At what pressure will R-410A (a refrigerant) boil at 35 C (95 F) Subjects: Behavior or characteristics of devices or systems Examples: How big a pump do I need to empty a swimming pool in 1 hour? How much air must I blow into a balloon for a given size? How much work is involved to inflate a flat tire or balloon?

4. Thermodynamic System and Control Volume
Control Volumes
Closed control volume: Open control volume:
Encloses a fixed amount of mass Mass can enter or leave
Also called control mass
Notice volume may change
Control surface A B
Control surface
Control volume A + B

5. Thermodynamic System and Control Volume
Closed control volume: Open control volume:
Encloses a fixed amount of mass Mass can enter or leave
CV: argon, volume can go up
Hot air balloon being inflated
Filling of a tank
Heating at constant volume

6. Complete system: Power Plant
Conversion of fuel energy into electricity and heat
Water
Loop
Heat
(Condenser)

7. Complete system: Refrigerator
Refrigerator pushes energy out of a cold space into a warmer space (room)
Refrigerant flows in a loop through 4 devices

8. Properties, Processes and Cycles
Phases: Solid, Liquid and Vapor (gas)
State: a specific condition expressed by a unique set of property values like P, T and density ρ.
Two independent properties are needed to specify a state
Intensive properties are independent of mass (P, T, ρ)
Extensive properties depend on mass (Mass, Volume, Energy)
Process: A change of a substance beginning at state 1 to a final state 2 through a continuous variation of the state.
Example: Heat a cup of cold water to be warm water
Example: Compress air in a cylinder to a smaller volume (bike pump)

9. Properties, Processes and Cycles, Continued
Process path or type: A specific succession of states is usually given a name that relates to the condition under which this happens. This is given by the way the device behaves as a process equation or device equation.
Example: The heating of water in a cup takes place at atmospheric pressure so it is called an isobaric process, pressure is constant.
Example: Heating of air in a constant volume container is called an isochoric process, volume is constant.
Example: Air is compressed in a piston cylinder while it is maintained at a constant temperature called an isothermal process.
Example: Air is compressed in a well insulated piston cylinder so it does not have any heating or cooling called an adiabatic process.
The type of process is often dictated by the device behavior and could also be called a device equation.

10. Properties, Processes and Cycles, Continued
Cycle: A process path that ends in the initial state. It can be a complex process or a combination of several simple processes.
Example: Water circulating in a steam power plant
Example: Refrigerant (like R-134a, R-410A or R-12) circulating in a refrigerator or air-conditioner.
Example: Air going through 4 sequential processes in a piston cylinder similar to what happens in a car engine. This is repeated in time.
Cycles do not (net) change the working substance which keeps looping in space (flow) or in time. However during the cycle the outside world exchanges energy with the working substance at different conditions during the cycle so the net effect is an energy conversion process.

11. UNITS SI or English: Units and Conversions: See Table A.1
SI: mass (kg), length (m), time (s), force (N)
F = ma has units N = (1 kg) (1 m/s2) = 1 kg m/s2
English: mass (lbm), length (ft), time (s), force (lbf)
F = mg has units lbf = (1 lbm) ( ft/s2) = lbm ft/s2
Mole: A fixed number of particles (No = 6.022*1023 particles per mol) distinguish between gram mole (mol) and kilomole (kmol).
m = n M where m is mass , n = number of moles, M is molecular mass
Units and Conversions: See Table A.1

12. UNITS

13. UNITS
Recall: lbf = lbm ft/s2

14. Specific Volume and Density
Specific volume: Volume per unit mass (v)
v = V/m limit for small volume
Density: Mass per unit volume (ρ)
ρ = m/V limit for small volume
Typical numbers SI:
Liquid water: v ≈ m3/kg and ρ ≈ 1000 kg/m3
Atmospheric air: v ≈ 1 m3/kg and ρ ≈ 1 kg/m3
See Tables for a few
typical substances.
SI: A3, A4, A5
Eng.: F2, F3, F4

15. Specific Volume and Density, English Units
Specific volume: Volume per unit mass (v)
v = V/m limit for small volume
Density: Mass per unit volume (ρ)
ρ = m/V limit for small volume
Typical numbers English:
Liquid water: v ≈ ft3/lbm and ρ ≈ 62.5 lbm/ft3
Atmospheric air: v ≈ 13.7 ft3/lbm and ρ ≈ lbm/ft3
See Tables for a few
typical substances.
SI: A3, A4, A5
Eng.: F2, F3, F4
Density [lbm/ft3]

16. Concept Questions

17. Pressure
Pressure is force per unit area (normal stress) 𝑃= lim 𝛿𝐴→0 𝛿𝐹 𝛿𝐴 With uniform P, piston at rest (F→ = F←) Fext = P Acyl Units for P 1 Pa = 1 N/m2 1 kPa = 1000 Pa = 1 kN/m2 1 bar = 105 Pa = 100 kPa = 0.1 MPa 1 atm = kPa = lbf/in2

18. Pressure

19. Pressure

20. Manometer/Barometer
Manometer
Barometer

21. Manometer
Manometer

22. Manometer
Manometer

23. Manometer/Barometer
Manometers
Barometer

24. Static/dynamic pressure
Static pressure in a fluid is only a function of depth below surface with given P. Shape does not matter.
Ships or floating objects are displacement hulls.
They push a mass of water away that equals their
own mass (m = ρV ).
A submarine or swimmer is neutrally buoyant when the displaced volume of water has a mass that equals the object mass.
The pressure below a speedboat or water ski is a static plus a dynamic pressure part. The water is being pushed away with significant acceleration.
P same

25. Pressure

26. Pressure
Liq water
Air
Ballast tank
Air tanks

27. Pressure P

28. Pressure

29. Manometer/Barometer

30. Pressure and Manometer Concept Questions
Figure 1.13 manometer

31. Energy and Temperature
A diatomic molecule, O2, N2 .
2 modes of rotation (ͼ x, z axis)
1 mode of vibration (in y axis)
A H2O molecule, 3 modes of vibration, 3 modes of rotation (not shown)

32. Temperature

33. Thermocouples, thermistors