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LAB-SCALE SOLAR THERMAL POWER PLANT
Concept, Design, Simulation & Fabrication
Project Members:Syed Mohammed UmairSulaiman Dawood BarrySaad Ahmed KhanArsalan Qasim
Project Advisor:Cdr. ShafiqDr. Sohail Zaki
Scope of Project
• To harness solar energy
• Selected DSG after comparison of various options
Objectives
• To design and fabricate a lab scale solar thermal power plant and generate about 40W power
• To demonstrate the principle of DSG using solar power
Energy Crisis In Pakistan
• Problems due to use of fossil fuels:
Crude oil is very expensive. Prices had once crossed over $140 per barrel
Rising oil prices lead to inflation
Oil embargo can cripple Pakistan economy
Energy Crisis In Pakistan
• Problems due to use of fossil fuels:
In year 2006, Pakistan imported crude worth 6.7 Billion Dollars (Dawn News)
To finance such a purchase, loans from IMF are needed. This increases debt burden.
Cost Of Energy In Pakistan
Possible Solution
• These problems can be reduced greatly by utilizing RENEWABLE ENERGY and SOLAR POWER IN PARTICULAR.
• Pakistan has vast tracts of desert regions which receive large quantities of solar flux throughout the year.
Power Generation Methods Using Parabolic Troughs
Steam heated with a heat transfer fluid. Steam heated directly by solar radiation. Combined cycle power generation using both solar and
fossil fuel.
Electric Generation UsingHeat Transfer Fluid
Uses parabolic troughs in order to produce electricity from sunlight They are long parallel rows of curved glass mirrors focusing the sun’s energy on an absorber pipe located along its focal line.These collectors track the sun by rotating around a north–south axis.
The HTF (oil) is circulated through the pipes.Under normal operation the heated HTF leaves the collectors with a specified collector outlet temperature and is pumped to a central power plant area.
Electric Generation UsingHeat Transfer Fluid
The HTF is passed through several heat exchangers where its energy is transferred to the power plant’s working fluid (water or steam)The heated steam is used to drive a turbine generator to produce electricity and waste heat is rejected.
Electric Generation UsingHeat Transfer Fluid
Electric Generation UsingDirect Steam Generation
The collectors reflect heat from the sun onto the receiver.Working fluid in the receiver is converted into steamAfter flowing through the super heater the high pressure steam is fed into the turbine/engineThe fluid passes through the condenser back to the feed water tank where the cycle begins again
Electric Generation UsingCombined Cycle
Hybrid system with a gas-fired turbine and a solar fieldSolar energy heats creates steam at daytime while fossil fuel used at night and peak timeThe running cost of the fuel will be reduced due to lesser fuel input.
Our Selection
Weighing all the advantages and disadvantages we have decided to select
Direct Steam Generation method as our project
Selection of Working Fluid
Steam R11 R113 R123 R134a R22 n-pentane0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
Efficiency for Same Working Pressure (140 kPa) for different working fluids in an Ideal Rankine Cycle
Working Fluids
Efficie
ncy
Selection of Working Fluid
• Water– Cheap abundant supply– Non toxic– Non flammable– Close cycle not necessary for operation
Cycle Selection
102 110 120 130 140 150 160 170 180 190 200 210 220 2300
0.01
0.02
0.03
0.04
0.05
0.06
0.07
Efficiency Vs Boiler Pressure
Closed Cycle
Open Cycle
Boiler Pressure
Effici
ency
Closed Cycle Open Cycle
Pressure (kPa) 101 101
Pump Inlet Quality 0.1 N/A
Pump Temperature (°C) N/A 25
Schematic
Design Constraints
• Temperature is 15 K superheat– Conserve engine life– Demonstrate the principle
• Pressure 140 kPa– Limitation of overhead tank– Unavailability of Low Flow rate pumps
Design Constraints
• Black nickel electroplating– Solar selective coating– Easily available
• Tube Length 1.6 meter– Test on existing parabola– Unavailability of Larger electroplating setup
Design Approach
• Mass flow rate• Energy Input
Design for 40 Watts
• Super-heater• Boiler
Heat Distribution • Superheater
Length• Heat Loss• Parabola Width
Optimization
• Drafting• Pressure Analysis
Finalization
Design Approach
• Mass flow rate• Energy Input
Design for 40 Watts
• Super-heater• Boiler
Heat Distribution • Superheater
Length• Heat Loss• Parabola Width
Optimization
• Drafting• Pressure Analysis
Finalization
Design Approach
• Mass flow rate• Energy Input
Design for 40 Watts
• Super-heater• Boiler
Heat Distribution • Superheater
Length• Heat Loss• Parabola Width
Optimization
• Drafting• Pressure Analysis
Finalization
Design Approach
• Mass flow rate• Energy Input
Design for 40 Watts
• Super-heater• Boiler
Heat Distribution • Superheater
Length• Heat Loss• Parabola Width
Optimization
• Drafting• Pressure Analysis
Finalization
Super-heater Surface Temperature against its Length
0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.110
200
400
600
800
1000
1200
1400
1600
1800
Superheater Length (m)
Surf
ace
Tem
pera
ture
(°C)
Boiler Analysis
0 0.1 0.2 0.3 0.4 0.5
0.600000000000001
0.700000000000001 0.8 0.92
4
6
8
10
12
14
Heat Transfer Coefficient Vs Water Level
Hea
t Tra
nsfe
r Co-
effici
ents
W/m
2-K Steam
Water
Water
Steam
DANGEROUS!!!
SAFER TO OPERATE
Boiler Analysis
0 0.1 0.2 0.3 0.4 0.5
0.600000000000001
0.700000000000001 0.8 0.91000
1200
1400
1600
1800
2000
2200
2400
2600
Reynolds Number Vs Water Level
Boiler Analysis
0 0.1 0.2 0.3 0.4 0.5
0.600000000000001
0.700000000000001 0.8 0.90.5
1
1.5
2
2.5
3
Entry Length of Thermal Bondary Layer Vs Water Level
Entr
y Le
ngth
of T
herm
al B
onda
ry L
ayer
(m)
Boiler Analysis
Boiling Regime: Nucleate
Safe Operation
Heat Loss Analysis
0.020.05
0.080.11
0.140.17 0.2
0.230.26
0.29
0.3200000000000030.35
0.3800000000000030.41
0.440.47 0.5
0.530
0.2
0.4
0.6
0.8
1
1.2
1.4
0 m/s1 m/s2 m/s3 m/s4 m/s5 m/s
Length of Superheater (m)
Tota
l Hea
t Los
s (k
W)
Boiler Heat Loss Comparison
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Bare TubeGlass Tube
Wind Velocity (m/s)
Hea
t Los
s (k
W)
Super-heater Heat Loss Comparison
0.020.040.060.080.10.120.140.160.180.20.220.240.260.280.30.3200000000000030.340.360.3800000000000030.40.420.440.460.480.50.520.54
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
2 m/s bare2 m/s glass5 m/s Bare5 m/s glass
Length of Superheater (m)
Hea
t Los
s (k
W)
Total Plant Heat Loss For Bare and Glass Tube
0.020.04
0.060.08 0.1
0.120.14
0.160.18 0.2
0.220.24
0.260.28 0.3
0.3200000000000030.34
0.36
0.380000000000003 0.40.42
0.440.46
0.48 0.50.52
0.540
0.2
0.4
0.6
0.8
1
1.2
1.4
Bare Tube with 5 m/sGlass Tube with 5 m/sBare Tube with 2 m/sGlass Tube with 2 m/s
Length of Superheater (m)
Hea
t Los
s (k
W)
Area Required for Each Combination
0.020.05
0.080.11
0.140.17 0.2
0.230.26
0.29
0.3200000000000030.35
0.3800000000000030.41
0.440.47 0.5
0.538
8.5
9
9.5
10
10.5
11
Bare Boiler + Bare SuperheaterBare Boiler + Glass SuperheaterGlass Boiler + Bare SuperheaterGlass Boiler + Glass Superheater
Length of Superheater (m)
Are
a of
Tro
ugh
(m2)
Parabola Width for Boiler and Superheat Sections
0.020.05
0.080.11
0.140.17 0.2
0.230.26
0.29
0.3200000000000030.35
0.3800000000000030.41
0.440.47 0.5
0.531
10
100
Bare BoilerGlass BoilerBare SuperheaterGlass Superheater
Length of Superheater (m)
Para
bola
Wid
th (m
)
Total Efficiency of Plant
0.020.05
0.080.11
0.140.17 0.2
0.230.26
0.29
0.3200000000000030.35
0.3800000000000030.41
0.440.47 0.5
0.530.8
0.85
0.9
0.95
1
1.05
1.1
1.15
Entirely Bare Tube 5m/sEntirely Envoloped with Glass Tube 5m/sEntirely Bare Tube 2m/sEntirely Envoloped with Glass Tube 2m/s
Length of Superheater (m)
Perc
enta
ge E
ffici
ency
(%)
Plant Layout
Variation of Super-heater Surface Temperature and Steam Exit Temperature with Boiler Pressure
120140
160180
200220
240260
280300
320340
360380
0
100
200
300
400
500
600
700
800
Superheater Surface TemperatureSteam Exit Temperature
Working Pressure (kPa)
Tem
pera
ture
(oC)
Variation of Plant Carnot Efficiency, Efficiency with Bare Tube and Glass Tube with Pressure
120130140150160170180190200210220230240250260270280290300310320330340350360370380
0
0.02
0.04
0.06
0.08
0.1
0.12
Carnot EfficiencyThermal Efficiency with Bare TubeThermal Efficiency with Glass Tube
Working Pressure (kPa)
Effici
ency
Heat Loss with Pressure
120130140150160170180190200210220230240250260270280290300310320330340350360370380
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Heat Loss Bare TubeHeat Loss Glass Tube
Working Pressure (kPa)
Tota
l Pla
nt H
eat L
oss
(kW
)
Variation Total Area Required with Pressure
120135
150165
180195
210225
240255
270285
300315
330345
360375
0
2
4
6
8
10
12
14
16
18
Area Required with Bare TubeArea Required with Glass Tube
Working Pressure (kPa)
Tota
l Are
a Re
quir
ed (m
2)
Cost breakupPart CostCopper tube 2,500Black nickel coating 400Parabola frame with mounting 9,000Valves and fittings 5,000Steam engine 5,000Mirror strips 2,500Miscellaneous 1,000Total 25,400
43
FEA Analysis
• Objective:– Determine the deformation in Supporting
Structure– Optimize the flow in the Superheater by• Reducing the vortex region• Reducing the Stagnation Pressure Drop
44
Stress and Strain Analysis
45
Super-heater Analysis
Inlet Region
46
Flow Inlet Angle: 45°
Vortex Region: Largest Stagnation Pressure Drop: Large
47
Flow Inlet Angle: -5°
Vortex Region: Moderate Stagnation Pressure Drop: Moderate
48
Flow Inlet Angle: -55°
Vortex Region: Negligible Stagnation Pressure Drop: Largest
49
50
51
52
53
54
55
56
Manufacturing Operations
57
58
59
60
61
62
63
64
65
Engine Operation Principle
66
Pump
ACHIEVEMENTS
• Presented two papers1. 3rd National Energy Confrence at QUEST
Nawabshah2. SPEC-2010 at NED University Karachi
• Won as Runner up at NED University
68
Conclusion