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Thermodynamics Final Review
Chapter 1: Introduction
Definitions:
System
Boundary
Surroundings
Closed system
Open system
Property
Extensive
Intensive
Specific Volume
Pressure
Temperature
Energy
First Law of
Thermodynamics
Work
Adiabatic
State Principle
Simple System
Two-Phase Regions
Saturation State
Clausius Statement
Kelvin-Planck
statement
Entropy Statement

Whatever we want to study
Distinguishes the system from the surroundings
Everything external to the system
System that contains the same matter, no transfer of mass
A given region of space through which mass flows
A macroscopic characteristic of a system to which numerical value is given
without knowledge of the previous behavior of the system
Dependent on the size or extent of the system
Independent of the size or extent of the system
Volume per units mass
Force per area
A physical property that determines whether two objects are in thermal
equilibrium
An extensive property that includes the kinetic and potential energy of
engineering mechanics
Energy is conserved
Force acting through a distance in the direction of that force
Without heat transfer
The number of independent properties of one plus the number of
relevant work interactions
One for which only quasistatic work mode is relevant *Equilibrium state is
fixed by specifying tow independent, intrinsic properties
Two phases exist in equilibrium (liquid-vapor, solid-liquid, solid-vapor)
State where a phase change begins or ends
It is impossible for any system to operate in such a way that the sole
result would be an energy transfer by heat from a cooler to a hotter body
It is impossible for any device that operates in a cycle to receive heat from
a single reservoir and produce a net amount of work
Change in the
net amount of
amount of entropy
Amount of entropy
entropy transferred
produced within the
Contained within
in across the system
system during the
The system
= boundary during
+ time interval
During some
the time interval
Time interval

Irreversible Process
Exergy

The system and all parts of its surroundings cannot be exactly restored to
their respective initial states after the process has occurred
Maximum theoretical work obtainable form an overall system

Chapter 2: Energy and First Law
-

Q – W = ΔU + ΔKE + ΔPE
Variable
Q
W
ΔU
ΔKE
ΔPE

-

Name
Heat Transfer
Work
Change in specific internal
energy
Change in kinetic energy
Change in potential energy

This is the closed system energy balance
𝑊 = ∫ 𝑝 𝑑𝑣

Cycles:
-

Process 1-2, 2-3, 3-1
ΔEcycle = 0
Power Cycle: Wcycle = Qin – Qout

-

Thermal Efficiency of Power Cycle: ɳ =

-

Refrigeration and Heat Pump Cycles: Wcycle = Qout – Qin

-

Performance of Refrigeration Cycle: 𝛽 =

-

Performance of Heat Pump Cycle: 𝛾 =

–

=1−
(𝛽 is the coefficient of performance)
(𝛾 is the coefficent of peroformance)

Chapter 3: Evaluating Properties
-

-

Quality: u = uf + x(uf – ug)
2 properties are needed to lock in a state:
o T, p
o x, T
o h, p
o saturated liquid, p
Questions to ask when moving form state one to state two:
o Is v constant?

o Is s constant?
o Is T constant?
o Are both states completely identified?

Chapter 4: Control Volume
- 𝑚̇ =

(

)
Ύ

=
Mass balance
Area through which mass flows
Velocity
Specific volume
Gas constant (on constants sheet)
Molecular weight (table A-1)
Pressure
Temperature

𝑚̇
A
V
Ύ
𝑅
M
P
T
- Energy Balance
0= 𝑄
o
o
o
o
o

̇
𝑣 −𝑣
− 𝑊̇ + 𝑚̇(ℎ − ℎ +
+ 𝑔(𝑧 − 𝑧 ))
2

Compressor
Turbine
Pump
Nozzle
Expansion Valves
o Heat exchangers

Chapter 5: 2nd Law
Cycles
Power
Refrigeration
Heat Pump
-

Power Cycle Reversibility
ɳ < ɳmax Irreversible
ɳ = ɳmax Reversible

max
ɳ
𝛽
𝛾

ɳ > ɳmax Impossible
-

Reversibility for any cycle
Ծcycle = 0 reversible
Ծcycle > 0 irreversible
Ծcycle < 0 impossible



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