Thermodynamic Analysis of Resources Used in Manufacturing Processes
Chapter 1.4: Thermodynamic processes
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Thermodynamic processes 1.4-1 Chapter 1.4: Thermodynamic processes Goal: generate work from heat Example: isothermal expansion Ideal gas laws: T Nk E B 2 3 T Nk pV B
Transcript of Chapter 1.4: Thermodynamic processes
Thermodynamic processes 1.4-1
Chapter 1.4: Thermodynamic processes
Goal: generate work from heat Example: isothermal expansion
Ideal gas laws: TNkE B23
TNkpV B
Thermodynamic processes 1.4-2
We know WQE but WQ , are not unique Guy Lussac thought experiment (1807)
Reversible and irreversible expansion
p
V
Thermodynamic processes 1.4-3
Def. 1.12: A reversible cyclic process periodically takes a work-substance through a cycle of equilibrium states under exchange of heat and work only. Practically: Stirling engine, heat pumps, refrigerator
Tho
Tcol
Thermodynamic processes 1.4-4
Def. 1.13: The efficiency of a reversible cyclic process as an engine is hotQ
W
All reversible cyclic processes have the same efficiency as a function of Thot and Tcold
Tho
Tcol
Thermodynamic processes 1.4-5
Carnot cycle
p
V
T
S
Thermodynamic processes 1.4-6
The efficiency of all reversible cyclic processes is cold
hot
hot
1TT
QW
Thermodynamic processes 1.4-7
Stirling cycle
p
V
Thermodynamic processes 1.4-8
Non reversible engines: real machines
Coal powered plants:
Theoretical: KT 2100hot KT 300cold 85.01hot
hot
hot
TT
QW
Thermodynamic processes 1.4-9
Examples: heating and cooling
KJ
TTQS
hotcold
37.011
KT 300hot
KT 270cold
JQ 1000
