The document provides an introduction to thermodynamics, including definitions of key concepts like thermodynamic systems, the three basic types of systems (open, closed, isolated), and the four laws of thermodynamics. It also defines fundamental units and nomenclature used in thermodynamics. Specific topics covered include the different forms of energy (potential, kinetic, internal, flow work, heat, mechanical work), entropy, and the signs used to indicate the direction of heat and work across system boundaries.

1. INTRODUCTION
REFERENCES:
 Power Plant Engineering by Morse
 Internal Combustion Engines by Maleev
 Engineering Thermodynamics by Burghardt and Harbach
REVIEW OF THERMODYNAMICS:
Thermodynamics
Branch of science which deals with the transformation of energy from one form to another, and the movement
of energy from one location to another.
Thermodynamic System
A region in space that occupies a given volume, has a specific boundary, and contains a thermodynamic
substance.
Diagram:
Illustration: (Piston-cylinder Arrangement)
Three Basic Types of Thermodynamic Systems
1. Open System
In this system, heat, work and mass (with its associated energy) all crosses the system
Diagram:
Illustration: (Steam Turbine)
2. Closed System
In this system, there is no mass flow, only heat and work can cross the system boundary
Diagram:
Realize Your Potential
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2. Illustration: (Refrigeration System)
3. Isolated System
In this system, nothing crosses the system boundary (no heat, no work, no mass)
Diagram:
Illustration: (Piston-cylinder Arrangement)
Basic Law of Thermodynamics
1. Zeroth Law state that when two bodies are in thermal equilibrium with a third body, the two are in thermal
equilibrium with each other.
Illustration:
2. First Law (Law of Conservation of Energy – states that energy itself cannot be created or destroyed but only
transformed from one form of energy to another). The sum of energies going out of the system must be equal
the sum of the energies going into the system.
Illustration: First Corollary (Closed or Non-flow System)
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and value those difficult lessons but do not ever dwell on the past. Simply move forward and make
better, more educated decisions from the lessons learned.

3. Illustration: Second Corollary (Open or Steady flow System)
3. Second Law is concerned with the availability of energy form a thermodynamic cycle and demonstrates the
impossibility of a perpetual motion machine.
A. Concept of Entropy: A natural process that starts in one equilibrium state and ends in another will
go in the direction that causes the entropy of the system and the environment to increase.
B. Kelvin-Plank statement: (Concept of thermal efficiency): It is impossible to operate an engine in a
cycle that will have no other effect than to extract heat from a reservoir and turn it into an
equivalent amount of work.
C. Reeves statement: Heat flows form a region of high temperature to one of lower temperature
D. Clasius statement: It is impossible for self-acting machine, unaided by an external agency, to
convert heat form one body to another at a higher temperature.
4. Third Law – “Entropy tends to a minimum constant value as the temperature tends to absolute zero.” For a
pure element this minimum value is zero, but for all other substances it is not less than zero, but possibly
more. From a practical standpoint it means that it is impossible to attain a temperature of absolute zero by
other than a reversible (ideal) processes
FUNDAMENTAL UNITS AND NOMENCLETURE:
Nomenclature Parameter English Engineering Units Metric SI Units
l length ft m
F, W force lbf N
m mass lbm, slugs kg or kgm
A area ft2 m2
V volume or total volume ft3 m3
v velocity ft/sec m/s
a acceleration ft/sec2 m/s2
m
. mass flow rate lbm/sec kg/s
. Q
V, volume flow rate ft3/sec m3/s
P pressure lbf/in2, psi N/m2, Pa
WP, P power hp Watt
E energy Btu N-m, J
t arbitrary temperature °F °C
T absolute temperature °R K
Total values (Capital Letters) Specific values (Small Letters)
Total Enthalpy H (kJ) Specific Enthalpy h (kJ/kg)
Total Volume V (m3) Specific Volume v (m3/kg)
Total Internal Energy U (kJ) Specific Internal Energy u (kJ/kg)
Total Entropy S (kJ/K) Specific Entropy s (kJ/ kg – K)
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better, more educated decisions from the lessons learned.

4. Isaac Newton’s Second Law of Motion
States that of an unbalanced force acts in a body: (1) the body will accelerate in the direction of the
unbalanced force, and (2) the acceleration will be proportional to the unbalanced force and inversely proportional to
the mass of the body
Illustration:
Where:
F = force of gravity
m = mass of the substance, slugs or lbm, kg
go = observed or local gravitational acceleration, ft/sec2, m/s2
gc = proportionality constant
gs = standard gravitational acceleration
Note:
Use standard gravitational acceleration gs if the observed or local gravitational acceleration go is not given
1. Given: 5 lbm (Eng’g units)
Required: F
2. Given: 5 slugs (Eng’g units)
Required: F
Note: 1 slug = 32.2 lbm = 14.594 kgm
3. Given: 5 kg (SI units)
Required: F
FORMS OF ENERGY:
Energies possessed by a body which has to be considered when analyzing a thermodynamic system.
Types or Forms of Energy:
A. Stored Energy
Energies stored within the body which goes or dependent upon the flow of the mass
1. Potential energy (PE)
2. Kinetic energy (KE)
3. Internal energy (U)
4. Flow work (Wf)
B. Transition Energy
Energies in transit (on the move) which are not dependent upon the flow of the mass
5. Heat (Q)
6. Mechanical work (W)
Don't Give Up
To reach success, you have to persevere. Even Thomas Edison had to learn this. When he was creating the incandescent light
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better, more educated decisions from the lessons learned.

5. 1. Potential energy (PE) – energy stored due to its elevation above any arbitrary datum line.
Note: 1 Btu = 778 ft - lbf = 0.252 kcal
2. Kinetic Energy (KE) – stored energy of a body by virtue of its motion
3. Internal Energy (U) – stored energy due to its motion of molecules and forces of attraction between them.
4. Flow work (Wf) – is the energy required to move the fluid across the boundary of the system
Enthalpy (H) – combination energy or useful energy.
5. Heat (Q) – is the energy crossing a system boundary because of a temperature differences between the
system and surroundings.
6. Mechanical work (W) – when force acts in the direction of motion
Note: 1 hp = 745.7 Watts
Have An Unstoppable Attitude
You need to have determination. With good intentions, there may be a close friend or family member that feels it would be
better if you focused your attention in another direction. Uphold your unstoppable attitude, determined to succeed.
better, more educated decisions from the lessons learned.

6. (+) W = work is done by the system (direction is going out of the system)
(-) W = work is done on the system (direction is going into the system)
(+) Q = heat is added on the system (direction is going into the system)
(-) Q = heat is rejected by the system (direction is going out of the system)
Entropy
Property which measures the microscopic disorder or randomness of the molecules of a thermodynamic
substance
Illustration:
Definition:
1. 1 British Thermal Units (1 Btu)
is the amount of heat needed by a 1 lbm of water to raise its temperature 1°F (1°R) at 14.7 psia
for water:
cpw = 1 Btu/lb-°F or 1 Btu/lb-°R
2. 1 kilo calorie (1 kcal)
is the amount of heat needed by a 1 kgm of water to raise its temperature 1°C (1K) at 1.0332 kg/cm2
for water:
cpw = 1 kcal/kgm-°C or 1 kcal/kgm-K
3. 1 kilo Joule (1 kJ)
is the amount of heat needed by a 0.2388 kgm of water to raise its temperature 1°C (1K) at 101.325
kPa
for water:
cpw = 4.187 kJ/kgm-°C or 4.187 kJ/kgm-K
Basic Properties of Thermodynamic Substances
Two general classifications
1. Intensive Property
is one that is independent of the mass of the substance
Pressure, Density, Specific volume, Specific weight, Specific gravity, Temperature and Specific internal energy
2. Extensive Property
Is one that is dependent on the magnitude of the mass of the substance
Mass, Weight, Volume and Energy
Mass – is the quantity of matter in the body
Weight – the force exerted by gravity on a given mass
Volume – is the amount of space occupied by the matter
Energy – is the capacity of a given body to produce physical effects external to the body
GENERAL GAS LAW EQUATION (EQUATION OF THE STATE)
The simplest thermodynamic system consists of a fixed mass of an isotropic fluid influenced by a chemical
reactions or external fields. Such system are described in terms of the three measurable coordinates pressure P,
volume V, and temperature T. in fact, they may characterized as PVT system. However, experiment shows that these
three coordinates are not all independent, that fixing any two of them determines the third. Thus there must be an
equation of state that interrelates these three coordinates for equilibrium states.
PV = mRT
Note: A gas can be considered ideal if its pressure is very low and the temperature is much higher than its critical
temperature.
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actually losing chances to move forward. Instead of thinking of challenges as problems, think of them as opportunities.
better, more educated decisions from the lessons learned.

7. By definition, ideal gases behave according to the various ideal gas laws
1. Boyle’s Law – if the temperature of the given quantity of a gas is held constant, the volume of gas varies
inversely with the absolute pressure during a change of state.
(T=C)
2. Charles Law
a. If the pressure of a particular quantity of gas is held constant, then, with any change of state, the
volume will vary directly as the absolute temperature
(P=C)
b. If the volume of a particular quantity of a gas is held constant, then, with any change of state, the
pressure will vary directly as the absolute temperature
(V=C)
Focus On Something You Like
To increase your chance of succeeding, you should concentrate your efforts on something you enjoy.
better, more educated decisions from the lessons learned.