EML 6451 Energy Conversion
HW Set 2
Due February 20, 2013
1. For an absorption refrigeration system using the solar energy as the heat source in the
generator section. The refrigerated space is kept at -10 oC at a heat removal rate of 8 kW.
The environmen
EML 6451 Lecture Notes (2-8)
2.4.5 Ideal Brayton Cycle with
Regeneration
Concept : Use the turbine exhaust waste heat to
preheat the flow before entering the combustor
For an ideal Brayton cycle with ideal regeneration
(=1), T3=1300K, T1=300K, p=8
Let us
\_/'
7 Em MW
ZécZLa/é 1/0 ZZr (240)»
.9214. '7 mm cm 1/, #54 05/
.54. WW
mkﬂﬂ€ G (/6
H» mm m : 0.
mymm apctrwt . /
am @2021: ' a m {Vt/inf
f /. 846M119 bras-«as amz, I ,' '
Maw! “ﬁlm/3L
: 01»sz ’ 616‘ 4/1/17.» avg/{74965 ,
mow/424’s 6L mm A,
EML 6451 Notes (2-6)
2.4 All Gas Cycles
Def : The working fluid in the system remains in gaseous phase (gaseous
states) all the time and everywhere. No phase-change takes place in the
system.
2.4.1 Methods of Heat Input for Heat Engines (HEs)
As we discus
Lecture Notes (2-1)
2.2 Traditional Chemical
Energy to Mechanical
Energy Conversion
Systems : Vapor and
Combined Power Cycles
(Ch. 6 in your text)
Ref : Cengel and Boles,
Thermodynamics, Third Ed.
CHAPTER
2
2.2.1 Carnot Cycle
It is the most efficient idea
EML 6451 Notes (2-4)
_ 2.3.3 Reheating and Regeneration
A. Rehearing
Remember the base case and three improvements
Case 77, Quality at turbine Improvement added
exiti —W
Base 26% 88.6% None
|—.—.
A p 33.5% 81.2% Lower PL=10 kKa
B _
37.5% 91.4% PL=10
' EIVI'L 6451 Notes (2-2)
2W) Condenser
75 kPa
Assumptions 1‘ Steady' operating conditions exist. 2 Kinetic aria-potential
energychanges‘are negligitg‘le. . " ' - ‘ i '
Analysis First we determihethe enfhaipies at various points in the cycle, using
dat
EML 6451 Notes (2-7)
2. 4. 4.4 Example ofldeal Brayton Cycle
An ideal Brayton cycle operating on a
pressure ratio of 8. The gas temperature
Compressor inlet and 1300K (Tmaxlat the
turbine inlet. Use the Air—standard
assumption to determine
The following:
2— I0
EML 6451 Lecture Notes (2-5)
2.3.4 Trigeneration (CCHP) '
CCHP—Combined Cooling, Heating and Power
The new component is COOLING.
We can use the power generated to perform the cooling (vapor
compressionrefrigerationcycle),but that does not fit to the
'4’) EML 6451 Lecture Notes (2-3)
2.3.2 Co—generation with Adjustable Loads
Example :
a State
1 Steam exits from the boiler at 7 MPa and 500 OC
— 2 same as State 1
3 same as State 1
4 500 kPa (ideal throttling from State 2)
5 500 kPa (partial exit from
. EM W/ W054 (20/) . My 17
2 ~41“? _ axial PM”? (ea/(>1 (re; [02 ﬁc/eau‘z ‘
0 9—54 Steam enters the turbine of a cogeneration plant at 7 MPa and 500°C.
One-fourth of the steam is extracted from the turbine at 600—kPa pressure for
process heating. The rema