The Swiss clean-tech global provider - SOLLAB School... · axial position [m] Intercept factors on...
Transcript of The Swiss clean-tech global provider - SOLLAB School... · axial position [m] Intercept factors on...
CSP Technology
June 2016
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Company overview
Airlight Energy is a Swiss private company that supplies proprietary solar technologies
for large-scale production of electricity and thermal energy
R&D Facility in Biasca, Switzerland
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A new paradigm in concentrating solar technologies
‘’Our 5’’ major innovations State of the Art
Air-based receiver
Operate up to 570°Non-polluting fluid
Oil/ molten salts receiver
Potentially polluting and expensive thermal fluid
Fiber-reinforced concrete structure
Durable, inexpensive, locally available material
Metallic structure
Expensive construction material
Film mirrors
Simple manufacturingLow cost per aperture area
Glass mirrors
ExpensiveFragile
ETFE pneumatic enclosure
No dust and low humidity insideTotal water recovery
No cover
Wasting of waterExposure to
environmental conditions
Packed-bed thermal energy storage
Inexpensive, locally available materialLow thermal losses
Oil/ molten salts storage
Potentially pollutingChemical instability
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• Durable: 60 years lifetime
• Cheap construction material
• Locally available
• Increased stiffness, better focusing, greater concentration
• Extensive use of local workforce and resources due to in situ manufacturing
• Anti-seismic mechanism able to withstand extreme seismic events
• Few big pieces allow a simple modular construction
Pre-cast fiber-reinforced concrete structure: optimized beam with accurate shape design
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TLC
TLE
TTT
ST
PT
FS
TTD+TTS
TTC
ComponentLxWxH Concrete volume Weight
[m] [m3] [t]TLC 17.54 x 1.35 x 2.36 7.87 19.7TLE 17.54 x 1.75 x 1.82 6.55 15.4TTT 12.13 x 1.10 x 5.34 21.13 53.0ST 3.48 x 2.31 x 0.73 1.93 5.0PT 1.50 x 0.97 x 1.25 0.61 1.5FS 5.50 x 4.38 x 0.3 8.47 20.7TTD / TTS 2.30 x 1.73 x 1.82 2.86 7.1TTC 2.30 x 1.35 x 2.36 2.86 7.8
Concrete elements
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Concrete components manufacturing
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Concrete components assembly
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Dampers
Hanging rod
Hanging rod spherical joint
Hanged collector base
Collector tracking mechanismHanging rod sustain structure
Foundation
Collector wheels
Anti-seismic mechanism
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The mirrors and receiver are protected inside a pneumatic enclosure with a controlled atmosphere, the external film is made of highly transparent ETFE
• ETFE is a widely available industrial product, no production bottlenecks
• Greater resistance than glass against scratching
• No dust and low humidity inside the enclosure
• Easy to wash and total recovery of washing and rain water
• Film assembled by ALE in Biasca and shipped in reels
Did you know that…
…ETFE (Ethylene tetrafluoroethylene) is a fluorine based plastic. After their useful life as pneumatic enclosure for CSP plants the ETFE foils can be recycled in the agricultural industry as greenhouse coverings
Pneumatic enclosure
Ait Baha plant, Morocco
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• Large aperture (9.7 m with 2 mirrors)
• High optical efficiency
• High concentration (60 suns average)
• Simple manufacturing
• Low cost per aperture area
• No production bottlenecks
Did you know that…
…the mirror foils are made from stretched polyethylene terephthalate (PET) a material commonly used in the packaging industry
Mirror foils are kept in shape by differential pressures, linear parabolic configuration
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Technical developments – Pneumatic sleeves for membrane length adjustment
p1p2p3p4
psleeve,1
psleeve,2
psleeve,4
psleeve,3
mirror membranes
pneumatic sleeves
2 sleeves per beam for compensation of:• manufacturing tolerances among concrete beams• deflection within the beam 2*2*12*4 = 48*4 sleeve pressures to adjust on 212 m long collector
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Technical developments – Concentrator shape measurement system
px camarctan( / )n d fθ = ⋅
Receiver position in camera image (n in pixel) is a measure for angular deviation of on-axis ray from the focus:
Acceptance anglechanges withtransversal coordinateon concentrator:
i macc
cos( )arctan ar
θΦ −Φ =
-150
-100
-50
0
50
100
150
-150 450 1050 1650 2250 2850 3450 4050
targ
et in
ters
ectio
n [p
ixel
]
transversal coordinate [mm]
Nominal arcspline
arcspline composed of 4 circular arcs
parabola
upper receiver limit
lower receiver limit
solar band
2θacc
2aiΦm
Φr
camera
receiver
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Technical developments – Mechanical-optical model of arcsplineconcentrator
Objective: determine arcspline shape for given p and psleeve
Solution: force balances for• N arcs of mirror membrane:
• N – 1 arcs of support membranes:
• N arcs of pneumatic sleeves:
01
( )j
k j jk
T p p R=
= −∑
sleeve sleeve sleevesleeve2cos
TT p Rϕ
= =
1 sup,( )j j j jT p p R−= −
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Technical developments – Arcspline pressure regulation
p = 0.95pnominal p = 1.05pnominal
p2
psleeve,2
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Operation – Experimentally measured arcspline shapes after pressure adjustment
intercept factor: 87% 95%
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Operation – intercept factors within single beam (left) and overview of full collector (right)
LEFT TLC RIGHTB 12 B
0.81 A A 0.740.69 B 11 B 0.640.85 A A 0.670.84 B 10 B 0.750.84 A A 0.670.55 B 9 B 0.610.82 A A 0.710.72 B 8 B 0.780.80 A A 0.540.87 B 7 B 0.780.90 A A 0.790.85 B 6 B 0.780.78 A A 0.730.65 B 5 B 0.810.87 A A 0.950.77 B 4 B 0.850.89 A A 0.780.83 B 3 B 0.660.87 A A 0.740.87 B 2 B 0.750.81 A A 0.830.82 B 1 B 0.78
A A
80% avg 74%0.0 0.2 0.4 0.6 0.8 1.0
123456789
101112131415161718
intercept factor [-]
axia
l pos
ition
[m]
Intercept factors on TLC 4 RIGHT
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• Use of conventional materials and no need for high-tech coatings or vacuum insulation
• Easy to manufacture
• Inexpensive and non-polluting thermal fluid, easy to integrate in existing processes
• High performance receiver with low emissivity
• Minimization of piping thanks to inlet and outlet on the same side
• Secondary trumpet mirror for spillage minimization and optical re-concentration
Air is used in a specifically developed receiver with shields insulations
Multi-shield radiative insulation
Linear secondary
concentrator (water-cooled) Glass
Cold air duct
Spiraltube coil cavity(chrysalis)
Microporousinsulation
Hot air duct
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Challenges
• Low volumetric heat capacity large volume flows leading to significant pressure drop
• Low thermal conductivity large active surface area needed for convection heat transfer
Advantages
• No costs and environmental issues• No operating temperature limit and phase
change in the considered temperature range• Near-ambient operating pressure• Allows for the use of inexpensive TES solutions
(pebble stone packed bed)• Straightforward to integrate in thermal
processes where heating is attained conventionally by combustion
- High primary concentration (Cgeom = 70xgeometric)- High optical efficiency (hopt= 0.87)- Split-trough design allowing for greater re-concentration
High-efficiency secondary (lineartrumpet)Cgeom = 100x hopt, sec = 0.98
High operation temperaturespossible
However, current HTFi) have temperature limitations (400 °C with thermal oil)ii) have a complex implementation (molten salts)iii) are difficult to be used in a trough configuration (direct steam)
Air as HTF
High-temperature air as HTF
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Straight pipe:
𝐿𝐿
𝐷𝐷
Array of straight tubes:
𝐿𝐿𝑁𝑁
𝐷𝐷
Array of cross-flow pipes in parallel flow arrangement:
𝑙𝑙
𝐿𝐿
𝐷𝐷
𝐷𝐷 𝑑𝑑
𝑁𝑁
Fundamental limitation of linear tubular receivers:
𝐷𝐷 ↑⇒ Δ𝑝𝑝 ↓,𝑁𝑁𝑁𝑁 ↓⇒ Δ𝑇𝑇 ↑
It would be ideal to control pressure drop and temperature difference independently
• Branching flow up in multiple parallel tubes yields 1 additional parameter
• Arranging them in cross-flow configuration yields 2 additional design parameters
Cross-flow design
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�̇�𝑞𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠,𝑠𝑠𝑎𝑎𝑠𝑠
�̇�𝑞𝑠𝑠𝑟𝑟𝑠𝑠𝑠𝑠𝑟𝑟,𝑐𝑐𝑠𝑠𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐
�̇�𝑞𝑐𝑐𝑠𝑠𝑐𝑐𝑐𝑐�̇�𝑞𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠,𝑠𝑠𝑟𝑟𝑟𝑟𝑠𝑠
�̇�𝑞𝑐𝑐𝑠𝑠𝑐𝑐𝑟𝑟,𝑤𝑤𝑐𝑐𝑐𝑐
�̇�𝑞𝑐𝑐𝑠𝑠𝑐𝑐𝑟𝑟,𝑤𝑤𝑠𝑠𝑠𝑠𝑠𝑠
�̇�𝑞𝑠𝑠𝑟𝑟𝑠𝑠𝑠𝑠𝑟𝑟,𝑐𝑐𝑡𝑡𝑎𝑎𝑟𝑟
�̇�𝑞𝐻𝐻𝐻𝐻𝐻𝐻𝑇𝑇
�̇�𝑚𝐻𝐻𝐻𝐻𝐻𝐻
Spiral tube coil cavity (“chrysalis”)
Advantages
• Cylindrical cavity → high apparent absorptivity• Lowest temperature at cavity opening → lower apparent
emissivity• Secondary flow in coil → high h and low ΔT • Low cost
The air "chrysalis"
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System modeled simultaneously from different perspectives:
• Optical design (PREC-ETHZ)• Cavity model
• Semi-analytical model of cavity coupled with ray-tracing (PREC-ETHZ)
• CFD model (ICIMSI-SUPSI)• Receiver insulation (ICIMSI-SUPSI)• Entire receiver airflow modeling (ICIMSI-SUPSI)
System models
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0
100
200
300
400
500
600
700
800
900
1000
10:19:12 11:31:12 12:43:12 13:55:12 15:07:12
DNI [W/m2] T Chrysalis 1 [°C] T Chrysalis 2 [°C] T Chrysalis 3 [°C]
T Chrysalis 4 [°C] T Chrysalis 5 [°C] T Runback 1 [°C] T Runback 2 [°C]
On-sun recevier prototipe test
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Assembled receivers
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0
50
100
150
200
250
300
350
400
0%
10%
20%
30%
40%
50%
60%
70%
80%
-17.5 -12.5 -7.5 -2.5 2.5 7.5 12.5 17.5 22.5 27.5 32.5 37.5 42.5 47.5 52.5
Year
ly D
NI [
kWh/
m2]
Colle
ctor
effi
cien
cy
Skew angle [deg]
Yearly DNI
Collcetor eff.
Collector efficiency 𝜂𝜂𝑐𝑐𝑠𝑠𝑠𝑠 = 𝜂𝜂𝑠𝑠𝑜𝑜𝑐𝑐 � 𝜂𝜂𝑐𝑐𝑡 as a function of incoming radiation skew angle. Yearly DNI as a function of the skew range for Ait-Baha, Morocco is also shown (N-S orientation of collector axis.)
Receiver performance
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• Continuous production, compensating intermittency of sun availability
• Low thermal losses in the range of 1% every 24h
• Highly competitive production costs
• Robust, fail-safe technology
• Locally available construction materials
• Non-polluting, non-corrosive requirements
• Simple manufacturing
• No maintenance required
Did you know that…
…this is a simple, proven and effective technology first patented in 1929
Detail of Ait-Baha pilot plant, Morocco
Simple storage using a closed concrete container filled with stone gravel
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Packed-bed thermal energy storage
R&D Facility in Biasca, Switzerland
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Packed-bed thermal energy storage
Ait Baha Plant, Morocco
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First CSP booster: the solar field feeds 3MWth to an existing 12MWel ORC turbine
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Schematic example for CSP plant, Ait-Baha, Morocco
CSP Booster plant layout and integration with existing process
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More than 50% of the value of the project is generated locally thanks to the use of locally available materials and local manufacturing.
Local content generation
For the construction phase of the Ait-Baha project approx. 25 local workmen were employed.
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Technology characterized by lower tecnical barriers and higher local content
Level of barriers for local manufacturing of CSP components (in MENA area)
State-of-the-art
CSP technologyAirlight Energy CSP technology
Civil works Low Low
EPC Medium Medium
Assembly Low Very low: precast assembly
ReceiverHigh
Low: locally available materials,
on-site assembly
Flat glass for mirrors High Not used: plastic foil mirrors (no glass)
Mirror (flat) High Not used: plastic foil mirrors (no glass)
Mirror (parabolic) High Not used: plastic foil mirrors (no glass)
Mounting structure Low Low
HTF High Not used: air as thermal vector
Connecting piping Medium Medium
Storage system Medium Low
Electronic equipment Low Low
Source: ESMAP, World Bank; Airlight Energy estimates
Airlight Energy has lowered level of barriers
preventing local manufacturing of CSP
components and could generate up to 60% of
value locally
For the purpose of this comparison the total investment cost does NOT include: EPC costs, power block, balance of plant (assumed to be the same for both technologies and therefore not considered for local content assessment
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CSP as standalone application or to boost energy intensive industrial processes
*Direct Normal Irradiance
DNI*
Standalone
>250 MW th, 50-100 MW el
Electricity generation Heat-dependent processes
Combined cycle booster
20-300 MW th
Coal plant integrated
20-300 MW th
Waste heat recovery
10-100 MW th, 3-30 MW el
Industrial process heat
3-100 MW th
Water desalination
50-300 MW th
Biofuel production / biomass gasification
10-100 MW th
>2’
000
kWh/
m2
1’60
0-2
’000
kWh/
m2
1’20
0-1
’600
kWh/
m2
High
Low
Thank [email protected]