8/10/2019 Advances in Concentrating Solar Power Collectors
1/69
Advances in Concentrating Solar PowerCollectors: Mirrors and Solar Selective
Coatings
C.E. Kennedy1National Renewable Energy Laboratory (NREL), 1617 Cole Boulevard, M/S 3321, Golden, CO
80401-3393, 303-384-6272, 303-384-6103 (fax), [email protected]
AIMCALScottsdale, AZ
October 10, 2007
NREL/PR-550-43695
Presented at the Association of Industrial Metallizers, Coaters and Laminators (AIMCAL) 2007 Fall Technical Conference,
21st International Vacuum Web Coating Conference held October 7-10, 2007 in Scottsdale
Arizona
8/10/2019 Advances in Concentrating Solar Power Collectors
2/69
Outline
Solar Market Potential Solar Reflectors Solar Selective Coating
Conclusion
8/10/2019 Advances in Concentrating Solar Power Collectors
3/69
Concentrating Solar Power TechnologiesPower TowerParabolic Trough Dish-Stirling
CPV Heliostat CPV Winston Collector
100kW LCPV Tracking
Solar concentrationallows tailored design
approachesCompact Linear
Fresnel Reflector
(CLFR)
http://www.jxcrystals.com/SolarPV.htmhttp://www.jxcrystals.com/SolarPV.htmhttp://www.jxcrystals.com/SolarPV.htmhttp://www.jxcrystals.com/SolarPV.htm8/10/2019 Advances in Concentrating Solar Power Collectors
4/69
DOE & WGA determined feasibility of1000MW in SW
Southwest Solar Resources
8/10/2019 Advances in Concentrating Solar Power Collectors
5/69
DOE & WGA determined feasibility of1000MW in SW
Southwest Solar Resources
Transmission Overlay
8/10/2019 Advances in Concentrating Solar Power Collectors
6/69
DOE & WGA determined feasibility of1000MW in SW
Southwest Solar Resources
Eliminate locations
< 6.75 kwh/m2/day
Transmission Overlay
8/10/2019 Advances in Concentrating Solar Power Collectors
7/69
DOE & WGA determined feasibility of1000MW in SW
Southwest Solar Resources
Eliminate locations
< 6.75 kwh/m2/day
Transmission Overlay
Exclude environmentally
sensitive lands, major
urban areas, and water
features
8/10/2019 Advances in Concentrating Solar Power Collectors
8/69
DOE & WGA determined feasibility of1000MW in SW
Southwest Solar Resources
Eliminate locations
< 6.75 kwh/m2/day
Transmission Overlay
Exclude environmentally
sensitive lands, major
urban areas, and water
features
Remove land areas >
(3%) & 1% average
land slope
Remove land
8/10/2019 Advances in Concentrating Solar Power Collectors
9/69
SW Solar Energy Potential
The table and map represent land that has no primary use today,
exclude land with slope > 1%,
8/10/2019 Advances in Concentrating Solar Power Collectors
10/69
Renewable Portfolio Standards
State RPS mandates successfully jump-starting desirable growth
LA
ID
UT
WY
AL
SC
TN
KY
INOH
NC
SD
KS
NE
AR
MS
OK
ND
MI
GA
AK
VAWV
DE: 20%by 2019
MD: 7.5% by 2019
VT: 10%by 2013*
NH: 16%
by 2025
MT: 15%
by 2015
CO: 20%by 2020
NV: 20%
by 2015
TX: 5,880 MWby 2015
NM: 20%
by 2020
AZ: 15%by 2025
CA:20%by 2010
33% by 2020
MN: 25% by 2025;
Xcel: 30% by 2020
IA:105 MW
WI: 10%
by 2015
IL: 25%by 2025
ME: 10%by 2017
NY: 24%by 2013
PA: 18%by 2020
WA: 15%by 2020
DC: 11%by 2022
NJ: 22.5%by 2021
CT: 23%by 2020
RI: 15%by 2020
MA: 4% new by 2009
FL
VA: 12%by 2022*
MO:11%by
2020*
HI: 20%by 2020
OR: 25%by 2025
NC: 12.5% by 2021
* Voluntary Goals
8/10/2019 Advances in Concentrating Solar Power Collectors
11/69
Market for Solar in US SW
California: 500 MW by 2010 8,000 MW by 2020 peaking demand
354 MW SEGS trough plants in CA 2 PPAs for 1.75 GW Dish Stirling plants in Southern
CA 500 MW (option to expand to 850 MW) Mojave Desert 300 MW (two options to expand to 900 MW) Imperial
Valley 553 MW PPA signed PGE, CA 300 MW PGE, CA Pending contractual announcement 175 MW PGE/FPL CLFR (commitment) 200 MW FPL CLFR (commitment) 1000 MW PGE (commitment) probably in CA
Arizona: 2,000 MW 1 MW trough plant in AZ
Nevada: 1,500 MW 64 MW trough project in NV New Mexico: TBD
West Texas: 1,000 + MW Colorado:500 MW after 2010
Numerous RFPs in CO, TX, AZ,
Florida: 300 MW CLFR (FPL Commitment) 10 MW initial (w/ option to expand to 300 MW) 500 MW FPL (commitment) in CA, FL, & other states
10,000 MW of CSP by 2020
8/10/2019 Advances in Concentrating Solar Power Collectors
12/69
International CSP ProjectDevelopments
1000MW CSP USA 30MW ISCCS Mexico
500MW CSP Spain
30MW ISCCS Morocco 30MW ISCCS Egypt 250MW SEGS Israel
400MW ISCCS Iraq 30MW ISCCS Algeria
100MW CSP South Africa
720 kW CPV Australia 154MW CPV Australia
8/10/2019 Advances in Concentrating Solar Power Collectors
13/69
Parabolic Trough Plants
Source: KJC Operating Company
8/10/2019 Advances in Concentrating Solar Power Collectors
14/69
Parabolic TroughCost Reduction Scenario
0.236
0.162
0.143
0.1200.110
0.1020.094
0.00
0.05
0.10
0.15
0.20
0.25
1 - 50 MW
Plant (NV)
1 - 100 MW
Plant (CA)
4 x 100MW
Solar Park
Advanced
Technology
@ 1000 MWe
Deployment
@ 2000 MWe
Deployment
@ 4000 MWe
Deployment
Nominal(LCO
E)
Location: Barstow, CA
Incentives: Current California
Deployment Assumes:
- 90% PR in Solar Field
- 95% PR in Power Plant
Competitive Range
CA MPR Range
Gas Price: $6 /MMBtu
Future
Good SolarResource Site
AdvancedTechnology
Learning &
Competition Increasing Plant
Size
AlternativeFinancing
Tax Neutrality forSolar Fuels
Tax Incentives
8/10/2019 Advances in Concentrating Solar Power Collectors
15/69
Goals for Improved
Optical Materials
>90% Specular reflectanceinto a 4-mrad cone angle Unofficially 95%
10 - 30 year lifetime Unofficially 30 y
Manufacturing cost$10.76/m2 ($1/ft2)
1992 Cost Goal
Adjusted for inflation to$15.46/m2 ($1.44/ft2)
Structural (self-supporting)mirror to $27/m2 ($2.50/ft2)
8/10/2019 Advances in Concentrating Solar Power Collectors
16/69
Technical Approach Samples supplied by:
Industry
Subcontracts Developed in-house
Optical Characterization: Perkin-Elmer (PE) Lambda 9 & 900 UV-VIS-NIR
spectrophotometers (250-2500 nm) w/ integratingspheres
PE IR 883 IR spectrophotometer (2.5-50 m)
Devices & Services (D&S) Field PortableSpecular Reflectometer (7, 15, & 25-mrad coneangle at 660 nm)
Outdoor (OET) &Accelerated ExposureTesting (AET):
Atlas Ci65 & Ci5000 WeatherOmeters (WOM) (1X& 2X Xenon Arc/60C/60%RH)
QPanel QUV (UVA 340@ 290- 340 nm/ 4 h UV at40 / 4 h dark at 100%RH)
1.0 & 1.4 kW Solar Simulators (SS) ( 5X Xenon300-500 nm. 1.0-kW SS 80C/ 80% RH,1.4 kW-SS-4 quadrants 2 RH &T, light /dark)
BlueM damp heat (85C/85%RH/dark)
3 meterologically monitored sites at Golden,Colorado (NREL), Miami, Florida (FLA), and
Phoenix, Arizona (APS)
3
2
1
3
2
1
8/10/2019 Advances in Concentrating Solar Power Collectors
17/69
Reflective Layer (wet-silver)
Low-iron Glass (4- or 5-mm thick)
Acrylic (w/ high UV stability)
2nd coat Paint Layer (heavy Pb)
(1% Pb)
1st coat Paint Layer (heavy Pb)
(2.5% Pb)
Parabolic Trough Glass MirrorArchitecture
Back Layer (Cu)
Thick glass is slumped
Three-coat paint system designed for outdoor applicationsFlabeg mirrors still use Cu back protection
Mactac adhesiveCeramic ad
8/10/2019 Advances in Concentrating Solar Power Collectors
18/69
Reflective Layer (wet-silver)
Low-iron Glass (4- or 5-mm thick)
Acrylic (w/ high UV stability)
2nd coat Paint Layer (heavy Pb)
(1% Pb)
1st coat Paint Layer (heavy Pb)
(2.5% Pb)
Parabolic Trough Glass MirrorArchitecture
Back Layer (Cu)
Thick glass is slumped
Three-coat paint system designed for outdoor applicationsFlabeg mirrors still use Cu back protection
Mactac adhesiveCeramic pad
8/10/2019 Advances in Concentrating Solar Power Collectors
19/69
Original Flabeg Mirror
85
90
95
100
0 10 20 30 40 50 60 70 80
Total UV Dose (100 x MJ/m2
)
%
HemisphericalR
eflectance
APS - OLDFLA - OLD
NREL - OLD
Ci65 - OLD
Equivalent NREL Exposure Time (years)
3 6 12 15 180 24219
8/10/2019 Advances in Concentrating Solar Power Collectors
20/69
Original vs. New Flabeg Mirror% Hemispherical Reflectance of Old Flabeg (w/Cu & Pb paint) vs New Flabeg (w/ Cu & low-Pb
paint) Mirrors as a function of accelerated exposure in Ci65 WOM (65C/65%RH/~3sun light
exposure) and BlueM (85C/85%RH/dark), and outdoors in Colorado
80
85
90
95
100
0 4 8 12 16 20 24
Exposure Time (Months)
%
HemisphericalReflect
ance
SWV - Old - BlueM
SWV - New - BlueM
SWV - Old - Ci65
SWV - New - Ci65
SWV - Old - NREL
SWV - New - NREL
8/10/2019 Advances in Concentrating Solar Power Collectors
21/69
Reflective Layer (wet-silver)
Low-iron Glass (3- or 4-mm thick flat)
2nd coat Paint Layer (lead-free
8/10/2019 Advances in Concentrating Solar Power Collectors
22/69
Alternate Thick Glass Mirror
65
70
75
80
85
90
95
100
0.0 3.3 6.7 10.0 13.3 16.7 20.0 23.3 26.6 30.0 33.3 36.6 40.0 43.3 46.6 50.0 53.3
Total UV Dose (100 x MJ/m2)
%
HemisphericalReflectance
NREL - Pilkington
NREL - Spanish
Ci65 - Pilkington
Ci65 - Spanish
qu va en xposure me years
1 2 3 4 50 6 7 8 9 11 12 13 14 15 1610
Pilkington: 4-mm glasscopper-free mirrors
Spanish: CristaleriaEspanola S.A. (SaintGobain) 3-mm glass,copper-free, lead-freepaint mirrors
8/10/2019 Advances in Concentrating Solar Power Collectors
23/69
Effect of Adhesive on Thick Glass Mirror
80
85
90
95
100
0.0 3.3 6.7 10.0 13.3 16.7
Total UV Dose (100 X MJ/m
2
)
%
HemisphericalR
eflectance
SPA/GE TSE 392-C ADH PIL/GE TSE392-C ADH
SPA/GE D1-SEA210B Pil/GE D1-SEA210B ADH
SPA/KRAFF SILKRAF ADH PIL//KRAFF SILKRAF ADH
SPA/DOW Q3-6093 ADH PIL/DOW Q3-6093 ADH
NREL Exposure Time (years)
1 2 3 4 50
8/10/2019 Advances in Concentrating Solar Power Collectors
24/69
80
85
90
95
100
0.0 3.3 6.7 10.0 13.3 16.7 20.0 23.3 26.6 30.0 33.3 36.6 40.0 43.3 46.6
Total UV Dose (100 X MJ/m2
)
%
HemisphericalReflectance
SPA/GE TSE 392-C ADH PIL/GE TSE392-C ADH
SPA/GE D1-SEA210B ADH PILS/GE D1-SEA210B ADH
SPA/KRAFFT SILKRAF ADH PIL/KRAFFT SILKRAF ADH
SPA/DOW Q3-6093 ADH PIL/DOW Q3-6093 ADH
Equivalent NREL Exposure Time (years)
1 2 3 4 50 6 7 8 9 1110 12 13 14
Effect of Adhesive on Thick Glass Mirror
8/10/2019 Advances in Concentrating Solar Power Collectors
25/69
Reflective Layer (wet-silver)
Low-iron Glass (~1 mm- thick)
Substrate (SS, Al)
Adhesive (PS, spray)
Paint Layer (Pb)
(Pb-free)
Thin Glass Mirror Architecture
Back Layer (Cu)
(Cu-less)
Thin glass mirrors are designed for indoor applications.
8/10/2019 Advances in Concentrating Solar Power Collectors
26/69
Thin Glass Corrosion
8/10/2019 Advances in Concentrating Solar Power Collectors
27/69
Thin Glass Mirror Matrix
LevelsFactors
MirrorType
BackProtection
Adhesive /Substrate
EdgeProtection
SubstrateCleaning
BackPriming
1 Naugatuck/Cu Epoxy 3M504FL/AL steel None SAIC 3M
2 Naugatuck/ No Cu Polyurethane 3M504FL/AL Exuded Adh. SES None
3 Glaverbel None 3M966/AL steel CPFilm4 3M966/AL
5 Mactac/AL steel
6 Mactac/AL
7 Epoxy/AL steel
8 Epoxy/AL
9 Urethane /AL steel
10 Urethane /AL
11 Contact /AL steel
12 Contact /AL
13 None
D-optimal fractional factorial algorithm using Design-Expert software
B: Back Protect
8/10/2019 Advances in Concentrating Solar Power Collectors
28/69
ANOVA Analysis
Glaverbel - best overallmirror in Mirror matrix test Commercial vs. prototype
1- vs. 2-coat paint system
Difference in EU and US lead-free
regulations Epoxy-based adhesive
probably good choice
No additional back
protection - survive thelongest
Polyurethane poor choice BlueM - more accelerated
exposure chamber
B1 EpoxyB2 Polyurethane
B3 None
Actual Factors
A: Mirror = Glaverbel
D: Test method = Ci5000
B: Back Protect
C: Adh/SS
Reflectance(SolWt
)
3M504FL/Alsteel
3M504FL/Al
3M966/Alsteel
3M966/Al
Mactac/Alsteel
Mactac/Al
Epoxy/Alsteel
E
ox/Al
Urethane/Alsteel
Urethane/Al
Contact/Alsteel
Contact/Al
None
30
40
50
60
70
80
90
100
D H t lt i il b t 6X
8/10/2019 Advances in Concentrating Solar Power Collectors
29/69
Damp-Heat results similar but ~6Xfaster than Ci5000
Discontinued in
Damp-Heat 5.9 MO
Discontinued in
Ci5000 18.9 MO
8/10/2019 Advances in Concentrating Solar Power Collectors
30/69
Thin Glass MirrorSpectral Reflectance of Naugatuck copperless mirrors with 1 coat paint system after
accelerated exposure in Blue M (dark / 85oC / 85%RH) chamber
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%
Reflectance
0.0 MO
1.72 MO
2.70 MO
3.99 MO
5.24 MO
7.51 MO
1-coat paint system formulated for Cu freemirrors.
8/10/2019 Advances in Concentrating Solar Power Collectors
31/69
Thin Glass Mirror
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%Refle
ctance
0.0 MOBlueM 3.52 MO
BlueM 7.21 MOCi65 3.16 MOCi65 6.15 MONREL 3.82 MONREL 9.57 MO
(Naug/Clearcoat/966
8/10/2019 Advances in Concentrating Solar Power Collectors
32/69
Enhanced Al Reflective Layer
Protective Oxide Topcoat
Polished Aluminum Substrate
Protective Overcoat
Aluminized Reflector Architecture
8/10/2019 Advances in Concentrating Solar Power Collectors
33/69
Aluminized Reflectors
80
85
90
95
100
0 333 666 999 1332 1665 1998 2331
Total UV Dose (MJ/m2)
%H
emisphericalR
eflectance
Original
Improved Miro2
Improved Miro2 Set#2
Miro/4270kk
xposure me y
1 2 3 4 50 6 7
Al i i d R fl t S l it
8/10/2019 Advances in Concentrating Solar Power Collectors
34/69
Aluminized Reflector Specularity
Alanod 4270/kk
FLA 11.8 m
APS 27.7 m
NREL 11 m
WOM 10.2 m0
20
40
60
80
100
0.0 3.3 6.7 10.0 13.3 16.7 20.0 23.3 26.6
Total UV Dose (100 x MJ/m2)
7-mradianSpecularReflectanceat660nm
APS
FLA
NREL
Ci65
Equivalent NREL Exposure Time (years)
1 2 3 4 50 6 7 8
Al i i d R fl t
8/10/2019 Advances in Concentrating Solar Power Collectors
35/69
Aluminized ReflectorSpectral Reflectance of Alanod MiroSun mirrors after outdoor exposure in Phoenix, AZ at APS
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%
Reflectance
0.0 MO
10.72 MO
Al i i d R fl t
8/10/2019 Advances in Concentrating Solar Power Collectors
36/69
Spectral Reflectance of Alanod MiroSun mirrors after outdoor exposure in Miami, FL at FLA
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%
Reflectance
0.0 MO
12.0 MO
Aluminized Reflector
Al i i d R fl t
8/10/2019 Advances in Concentrating Solar Power Collectors
37/69
Aluminized ReflectorSpectral Reflectance of Alanod MiroSun mirrors after outdoor exposure in Golden, CO at
NREL
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%
Reflectance
0.0 MO
5.16 MO
11.37 MO
Al i i d R fl t
8/10/2019 Advances in Concentrating Solar Power Collectors
38/69
Spectral Reflectance of Alanod MiroSun mirrors after accelerated exposure in Ci65 WOM
(1 sun / 60oC / 60%RH) chamber
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%R
eflectance
0.0 MO
3.51 MO
6.63 MO
11.54 MO
Aluminized Reflector
Aluminized Reflector
8/10/2019 Advances in Concentrating Solar Power Collectors
39/69
Spectral Reflectance of Alanod MiroSun mirrors after accelerated exposure in Blue M (dark /
85oC / 85%RH) chamber
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%R
eflectance
0.0 MO
4.47 MO
6.66 MO
9.41 MO
13.84 MO
16.95 MO
Aluminized Reflector
Aluminized Reflector
8/10/2019 Advances in Concentrating Solar Power Collectors
40/69
Aluminized ReflectorSpecular Reflectance at 7- and 25-mradians at 660 nm of Alanod MiroSun mirrors after
accelerated exposure in Blue M (dark / 85oC / 85%RH), WOM (1 sun / 60
oC / 60%RH)
chambers, and outdoor exposure at NREL, APS, FLA, and Sandia
30
40
50
60
70
80
90
100
0 3 6 9 12 15 18 21 24
EXposure Time (Months)
%
SpecularReflectance
NREL - 25 mr
NREL - 7 mr
NREL - SWV
APS - 25 mr
APS - 7 mr
APS - SWV
FLA - 25 mr
FLA - 7 mr
FLA - SWVWOM - 25 mr
WOM - 7 mr
WOM - SWV
Blue M - 25 mr
BlueM - 7 mr
BlueM - SWV
Sandia -25mr
R fl T h Sil d P l
8/10/2019 Advances in Concentrating Solar Power Collectors
41/69
ReflecTech - Silvered PolymerReflector Architecture
UV-Screening Superstrate
Base Reflector
Bonding Layer
Flexible Polymer Substrate
R fl T h P
8/10/2019 Advances in Concentrating Solar Power Collectors
42/69
ReflecTech Prototypes
70
75
80
85
90
95
100
0 3.3 6.6 9.9 13.2 16.5 19.8 23.1 26.4
Total UV Dose (100 x MJ/m2)
%H
emisphericalRe
flectance
UV-Screen/SS95-NRELReflecTech A-NRELReflecTech B-NRELUV-Screen/SS95-WOMReflecTech A-WOMReflecTech B-WOM
Equivalent NREL Exposure Time (years)
0 1 2 3 4 5 6 7 8
R fl T h III NREL
8/10/2019 Advances in Concentrating Solar Power Collectors
43/69
ReflecTech III -NRELSpectral Reflectance of ReflecTech pilot-run#3 (06-48) silver polymer mirrors after outdoor
exposure in Golden, CO at NREL
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%
Reflectan
ce
0.0 MO
3.82 MO
ReflecTech 06-48
R fl T h III NREL
8/10/2019 Advances in Concentrating Solar Power Collectors
44/69
Spectral Reflectance of ReflecTech pilot-run#3 (06-60) silver polymer mirrors after outdoor
exposure in Golden, CO at NREL
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%Reflectan
ce
0.0 MO3.82 MO
ReflecTech (06-60)
ReflecTech III -NREL
R fl T h III Ci65 WOM
8/10/2019 Advances in Concentrating Solar Power Collectors
45/69
ReflecTech III Ci65 WOMSpectral Reflectance of ReflecTech pilot-run#3 (06-48) silver polymer mirrors after
accelerated exposure in Ci65 (1 sun / 60oC / 60%RH) chamber
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%Reflectan
ce
0.0 MO
3.16 MO
6.15 MOReflecTech (06-48)
R fl T h III Ci65 WOM
8/10/2019 Advances in Concentrating Solar Power Collectors
46/69
Spectral Reflectance of of ReflecTech pilot-run#3 (06-60) silver polymer mirrors after
accelerated exposure in Ci65 (1 sun / 60oC / 60%RH) chamber
0
20
40
60
80
100
250 500 750 1000 1250 1500 1750 2000 2250 2500
Wavelength (nm)
%
Reflectance
0.0 MO
3.16 MO
6.15 MO
ReflecTech (06-
ReflecTech III Ci65 WOM
Front Surface Solar Reflector
8/10/2019 Advances in Concentrating Solar Power Collectors
47/69
Top Protective Layer (1-4m Al2O3)
Front Surface Solar ReflectorArchitecture
IBAD Al2O
3
Front Surface Solar Reflector
8/10/2019 Advances in Concentrating Solar Power Collectors
48/69
Reflective Layer (100 nm Ag)
Top Protective Layer (1-4m Al2O3)
Substrate (PET)
Front Surface Solar ReflectorArchitecture
Front Surface Solar Reflector
8/10/2019 Advances in Concentrating Solar Power Collectors
49/69
Reflective Layer (100 nm Ag)
Top Protective Layer (1-4m Al2O3)
Substrate (PET) (Chrome Plated Steel,
Leveled Stainless Steel,
or Aluminum)
Anti-soiling Layer (100 nm TiO2)
Adhesion Promoting Layer (APL) (1-10 nm)
Front Surface Solar ReflectorArchitecture
Metal Back Layer (30 nm Cu optional)
Outdoor exposure at NREL of
8/10/2019 Advances in Concentrating Solar Power Collectors
50/69
80
85
90
95
100
0.0 3.3 6.7 10.0 13.3 16.7 20.0Total UV Dose (100 x MJ/m
2)
%He
misphericalReflectance
2um Al2O3/Ag/Cu 13AUG02-3 20nm/s
3.5um Al2O3/Ag/Cu 2AUG02 20nm/s1.5um Al2O3/PL/Ag/Cu 13AUG02-1 20nm/s
4.5um Al2O3/PL/Ag/Cu 15AUG02-1 20nm/s
Al2O3/Ag/Ti 27AUG02 20nm/s
Batch 1 nm/s
NREL Exposure Time (y)
1 2 3 40 5 6
Outdoor exposure at NREL ofRoll-Coated IBAD Al2O3 Samples
Both adhesion-promoting interlayer andTi backlayer were among most durable samples but:
Adhesion layer may slightly improve durability Ti backlayer may slightly degrade durability
Need more
exposure time todetermine lifetime
Cost Analysis
8/10/2019 Advances in Concentrating Solar Power Collectors
51/69
Cost Analysis
0
10
20
30
40
50
0 50 100 150 200 250 300
Al2O3Deposition Rate (nm/s)
Tot
alProductionC
osts($/m
2)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Ann
ualProduction
(1x10
6m
2)
1 zone
2 zones3 zones1992 Cost GoalCost Goal in 2004$1 zone Ann. Prod.2 zones Ann. Prod3 zones Ann. Prod. PET substrate
1-m Al2O3 Modified ASRM $200/h machine
burden 1200-mm web
High-purityHigh-volume(i.e.,$200/kg)
Al2O3
30% yield Coating 79%
time 10 to 200 nm/s
rate Machine cost:$2M-$4.1M
Loan%/length:12% for 5 yrs
1 vs. 2 vs. 3zones in 1
machine
Field Requirements for
8/10/2019 Advances in Concentrating Solar Power Collectors
52/69
Field Requirements forAdvanced Receivers
Receivers: 4 m (13.1 ft) long 70 mm (2.25 in) diameter
New 64 MWe Nevada plant 820 collectors and each
collector has 24 (96 m)receivers 19,680 receivers 82 km of receivers (50 mi)
Existing SEGS plants have5x this many receivers
New 553 MW plant willneed 8.5x this manyreceivers
3-4%/yr Failure Rate
~$1000/tube
Advanced Selective Coating Goals
8/10/2019 Advances in Concentrating Solar Power Collectors
53/69
Advanced Selective Coating Goals
200C (0.31 kW/m2)
300C (0.80 kW/m
2
)
400C (1.78 kW/m2)
500C (3.56 kW/m2)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
100 1000 10000 100000
Wavelength (nm)
BlackbodyIrradiance(W/m2-nm)
0
20
40
60
80
100
%Reflect
ance()
Direct AM 1.5 (0.77 kW/m2)
Ideal Solar Selective
Advanced Selective Coating Goals
8/10/2019 Advances in Concentrating Solar Power Collectors
54/69
Advanced Selective Coating Goals To develop receiver
coatings that have:
Good optical andthermal performance:absorptance () 96%,
& emittance () 7%>400C
High temperaturestability in air attemperatures 550C
Manufacturingprocesses withimproved quality control
Lower cost
200C (0.31 kW/m2)
300C (0.80 kW/m2)
400C (1.78 kW/m2)
500C (3.56 kW/m2)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
100 1000 10000 100000
Wavelength (nm)
BlackbodyIrradiance(W/m
2-nm)
0
20
40
60
80
100
%
Reflectance()
Direct AM 1.5 (0.77 kW/m2)
Ideal Solar Selective
High Temperature Solar
8/10/2019 Advances in Concentrating Solar Power Collectors
55/69
0.10
0.11
0.12
0.13
0.14
0.15
0.80 0.82 0.84 0.86 0.88 0.90 0.92
Energy Absorbed by Receiver
eveze
osto
nergy
= 0.05
= 0.15
= 0.25
Black Chrome
Mo-Cermet
UVAC (t)
UVAC (s)
New
Cermet (s)
Goal
High Temperature SolarSelective Coating Development
Selective coatingproperties impactcollector opticalperformance andthermal losses.
Improvements inthe receiver canenhance collectorefficiency & lowercost.
The internationalcommunity
currently leads thisarea and thereexists minimal USresearch & no USmanufacturer ofhigh-temperatureselective coatings.
Reduced
Thermal
Losses
(lower )
Increased Optical Properties
(higher )
Types of Selective Coatings
8/10/2019 Advances in Concentrating Solar Power Collectors
56/69
Types of Selective Coatings
Intrinsic selective
material
SubstrateIntrinsic absorber
Dielectric
Metal
Dielectric
Metal
Substrate
Multilayer absorbers ARAR
AR
AR
LMVF cermet
HMVF cermet
LMVF cermet
HMVF cermet
Metal
Substrate
Multiple cermet
Double cermet
AR
LMVF cermet
HMVF cermetMetal
Substrate
Graded cermet
Graded metal
dielectric composite
Metal
Substrate
Surface texturing
Metal
Substrate
Literature Review of Candidate
8/10/2019 Advances in Concentrating Solar Power Collectors
57/69
High-temperature (> 400C) SolarSelective Materials
Graded Mo,W, ZrB, Pt- Al2O3 cermets
Si tandem absorber
Black Co, Mo,W
Double cermets- SS-AlN, AlN/Mo, or AlN/W
4-layer V-Al2O3, W-Al2O3, Cr-Al2O3, Co-SiO2, Cr-SiO2,Ni-SiO2
Double AR
Multilayers; Al-AlNx-AlN
Au/TiO2 cermet ZrCxNy/Ag
Ti1-xAlxN
Quasicrystals multilayers & cermets
Surface Texturing
Desirable Properties for Stable
8/10/2019 Advances in Concentrating Solar Power Collectors
58/69
pCoating in Air > 400
C High thermal & structural stabilities for combined & individual layers
Elevated melting points Large negative free energies of formation
Materials that form a multicomponent oxide scale
Single-compound formation
Lack of phase transformations at elevated temperature
Suitable texture to drive nucleation, subsequent growth of layers with suitablemorphology Stable nanocrystalline or amorphous materials
Excellent adhesion between the substrate and the adjacent layers Enhanced resistance to thermal and mechanical stresses
Acceptable thermal and electrical conductivities Higher-conductivity materials have improved thermal shock resistance
Some ductility at room temperature reduces thermal-stress failures
Good continuity and conformability over the tube Compatibility with fabrication techniques
NREL Modeled Selective Coating
8/10/2019 Advances in Concentrating Solar Power Collectors
59/69
NREL Modeled Selective Coating
Commercial (as tested) Modeled
Black Cr Mo-Cermet
UVAC # 6A # 6B
Solar
Absorptance 0.916 0.938 0.954 0.959 0.950Thermal Emittance@
25C 0.047 0.061 0.052 0.013 0.027
100C 0.079 0.077 0.067 0.017 0.033
200C 0.117 0.095 0.085 0.028 0.040
300C 0.156 0.118 0.107 0.047 0.048
400C 0.216 0.146 0.134 0.074 0.061
500C 0.239 0.179 0.165 0.110 0.073
Comparison of theoretical optical properties for NRELs modeled prototype solar selective
coating with actual optical properties of existing materials.
Modeled NREL Selective Coating
8/10/2019 Advances in Concentrating Solar Power Collectors
60/69
Modeled NREL Selective Coating
0.00
0.20
0.40
0.60
0.80
1.00
0 1 10 100
Wavelength, um
Reflectance&
E
(norm.)
400C Black Body
ASTM G173-03
AM 1.5
Direct Normal
UVAC A
Ideal
Selective
Coating
Advanced
NREL #6A
Modeling Key Results
8/10/2019 Advances in Concentrating Solar Power Collectors
61/69
Modeling Key Results
Solar Selective Coating Development Modeled solar-selective coatings with =0.959 and
=0.061 that meet CSP goals
Emittance excellent & absorptance of modeled
coatings is very good but further improvements are
expected. However, trade-off exists between
emittance and absorptance.
Deposition Capabilities
8/10/2019 Advances in Concentrating Solar Power Collectors
62/69
epos t o Capab t es
Load-Lock Chamber
Pulsed DC Sputtering Chamber 3 - linear arrays of 5 - 1.5 Mini-mak
guns 2 - 12 planar cathodes
Electron-Beam/IBAD Chamber
6 multi-pocket e-beam source Co-deposition bottom plate IBAD w/ 12 Linear Ion Gun
System
12x12 ambient or heated substrate 4 Reactive Gases
Turbo molecular drag pumps 2x10-8 torr
Monitoring RGA Quartz Crystal Monitor Pressure/Gas
Computer
Three-Chamber In-line System
Prototyping Key Results
8/10/2019 Advances in Concentrating Solar Power Collectors
63/69
Prototyping Key Results Key issue is making deposited coating
XPS showed evaporation from compounds producedlayered stoichiometry Despite depositing layers with over- and under-thickness and
compound layered structure, the optical performance of theprototype NREL#6A was quite encouraging.
Need to codeposit materials Required significant upgrade to equipment
Installed codeposition guns & sweeps
Pneumatic shutters
Second quartz crystal sensor Upgrade computer & RGA software
+ associated air, water, & electrical
Automating control
Prototyping Key Results
8/10/2019 Advances in Concentrating Solar Power Collectors
64/69
Prototyping Key Results Codeposit individual layers and modeled coating
Codeposition development
Deposited individual layers Deposited modeled structure Characterize properties
Optical performance lower than modeled Typically optical coating need error 5% because of manual control
Install optical monitor Provide positive feedback between quartz crystal and optical
monitor Automate control remove human error and provide steering
and cutting at sensitive turning points allowing mid-coursecorrections to be made
Compositional errors because stoichiometry not optimized
Composition with highest reflectance Phase formation from Pretorius effective heat of formation
model & TGA Optimize morphology with ion assist
Selective Coating Performance
8/10/2019 Advances in Concentrating Solar Power Collectors
65/69
Selective Coating Performance can be measured at higher temperatures but is typically reported based on
calculations from reflectance measurements fitted to the black body curve
Actual performance of the absorber at high temperatures commonly doesnot correspond to the calculated Small errors in lead to large errors in
is a surface property & depends on surface condition of material and substrate
Surface roughness Surface film
Oxide layers Selective coatings can degrade at high T due to
Thermal load (oxidation) High humidity or water condensation on the absorber surface (hydratization and
hydrolysis) Atmospheric corrosion (pollution)
Diffusion processes (inter-layer substitution) Chemical reactions Poor interlayer adhesion
Therefore it is important that is measured accurately and to measure ofthe selective coating at operating temperatures & conditions before usingcalculated
Round Robin &
Purchase Perkin Elmer 883 IR spectrophotometer
Thermal Stability
8/10/2019 Advances in Concentrating Solar Power Collectors
66/69
y Thermal stability is sometimes given based on the thermal
properties of the individual materials or the processingtemperature parameters
Actual durability data is uncommon for high temperatureabsorber coatings Durability or thermal stability is typically tested by heating the
selective coating, typically in a vacuum oven but sometimesin air, for a relatively short duration (100s of hours)compared with the desired lifetime (5-30 years)
IEA Task X performance criterion (PC) developed for flat platecollector absorber testing (i.e., non-concentrating, 1-2X sunlightintensity)
No analogous criterion known for testing high-temperature selectivecoatings for CSP applications
Building capability for long term testing of thermal stability
Purchased & installed high-temperature
(600C) inert gas oven
Conclusion
8/10/2019 Advances in Concentrating Solar Power Collectors
67/69
Conclusion DOE, the WGA, state RPS mandates, and feed-in tariffs
have successfully jump-started growth in CSP technologies
that would require 7 to 10 million square meters of reflectorand more than 600,000 HCEs over the next 5 years.
Commercial glass mirrors, Alanod, and ReflecTech maymeet the 10-yr lifetime goals based on accelerated
exposure testing. Predicting an outdoor lifetime based onaccelerated exposure testing is risky because AET failuremechanisms must replicate those observed by OET.
Experimental IBAD Al2O3 front surface mirror has highpotential to meet need; but needs development by roll-coating company
None of the solar reflectors available have been in test longenough to demonstrate the 10-year or more aggressive 30-
year lifetime goal, outdoors in real-time
Conclusion
8/10/2019 Advances in Concentrating Solar Power Collectors
68/69
Conclusion Modeled solar-selective coatings with =0.959 and
=0.061 that meet CSP goals
Emittance excellent & absorptance of modeled coatingsis very good but further improvements are expected.However, trade-off exists between emittance andabsorptance.
Key issue then becomes trying to make the coating Prototype development underway. Individual and
modeled structure deposited by e-beam compound andelemental codepostion & characterized. Need toeliminate thickness errors by upgrading monitor andcontrol and determine optimum stoichiometry.
Purchased & installed PE 883 IR Spectrophotometer(2.5- 50) and high-temperature inert gas oven. Round-robin data being analyzed and commercial & prototypedcoating samples being put into test
Patent being pursued
Acknowledgments
8/10/2019 Advances in Concentrating Solar Power Collectors
69/69
AcknowledgmentsAlanod, Glaverbel, Naugatuck, ReflecTech, SAIC, and SES for providing
solar reflective samples.
Schott and Solel for providing solar selective samples.AZ Technology and Surface Optics Corporation for high-temperature optical
measurements .
Armstrong World Industries: Dr. J. S. Ross
Northeastern University: Dr. Jackie Isaacs
Penn State University: Prof. Singh, Tom Medill, and Dale DonnerSAIC: Dr. Russell Smilgys and Steve Wallace
Stat-Ease: Wayne F. Adams
Swisher and Associates: Dick Swisher
NREL:
Lynn Gedvilas, Gary Jorgensen, Mark Mehos, Judy Netter, CraigPerkins, Hank Price, Kent Terwilliger, and Student interns: MicahDavidson, Anthony Nelson, Michael Milbourne, and Christopher, andAndrea Warrick.
DOE supported this work under Contract No DE AC36 99GO10337
Top Related