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1. Chapter Basics
1
1. Energy demand and definition of solar thermal power
2. History of solar thermal power
3. Physics and thermodynamics
4. Measurements and solar potential
Content
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1. Primary energy demand worldwide - today
0,0
2000,0
4000,0
6000,0
8000,0
10000,0
12000,0
14000,0
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
Milliontonnesoilequ
ivalent
Source: BP Statistical Review of World Energy June 2011
2010:
12.002 Million tonnes of oil
equivalent ~ 140,000 TWh
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1. Primary energy demand worldwide - tomorrow
0,0
2000,0
4000,0
6000,0
8000,0
10000,0
12000,0
14000,0
16000,0
18000,0
1990 1995 2000 2005 2010 2015 2020 2025 2030
Milliontonnesoilequ
ivalent
Source: BP Energy Outlook 2030: January 2011
2030:
16.432 Million tons of oil equivalent >
190,000 TWh
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1. Solar Thermal Power Plants - What is this?
Not to be mixed with:
Solar thermal systems (flat and tubular collectors) or
photovoltaic systems
There are two types of solar thermal power plants:
Using concentrated incident solar radiation on an absorber(CSP
Concentrated Solar Power)
Without using concentrated solar radiation
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2. History Ancient Age
1000 BC: In Central America, parabolic reflectors were used as
lighters
3rd Century BC: Greeks attacked enemy ships using concentrated
sunlight (Archimedes)
Source: independent.co.uk
1000
BC
2000
AD
500
AD
0500
BC1500
AD
1000
AD
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2. History Ancient Age
100 AD Heron of Alexandria: Solar driven water heater
Till 400 AD, the Vestal Virgins in Rome ignited the sacred fire once
a year using a burning lense
1.000
BC
2000
AD
500
AD
0500
BC1500
AD
1000
AD
Source: archinform.net
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2. History - Middle ages to Modern times
1.000BC
2000AD
500AD
0500BC
1500AD
1000AD
1500 200017001600 19001800
No significant developments until 1500 AD
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2. History - Middle ages to Modern times
In 1515, Leonardo da Vinci experimented with parabolic-mirror
concentrators to improve cloth drying
1500 200017001600 19001800
Source: culturalheritageimagin.org
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2. History - Middle ages to Modern times
1690: Ehrenfried Walter von Tschirnhaus developed focusing
mirrors with a diameter of 1.60 mfor experiments in porcelain
making
1772: Isaac Newton experimented with concave mirrors
1500 200017001600 19001800
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2. History - Middle ages to Modern times
1816: Robert Stirling developed the Stirling engine
Source: stirling.5x.to
1500 200017001600 19001800
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2. History - Middle ages to Modern times
Further developments in solar ovens / cookers and first
steps toward the development of solar cell
1876: William Adams wrote a book titled
SolarHeat: A Substitute for Fuel in Tropical Countries
1500 200017001600 19001800
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2. History - Middle ages to Modern times
1878: Augustine Mouchot introduced a solar steam generator at
the world exhibition in Paris
Source: Detail.de
1500 200017001600 19001800
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2. History Modern times
1913: Frank Shuman: 55PS-Plant (40 kW) in Egypt (3,500 m) with
parabolic collectors. Later on, the plant was closed and destroyed.
Source:
solarhaven.org
1500 200017001600 19001800
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Hardly any further development until the 1970s
Development during 70s to 80s was rather theoretical in nature
and hardly any plants were built.
2. History Modern times
1.000BC
2000AD
500AD
0500BC
1500AD
1000AD
1980 201020052000199519901985
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2. History Modern times
1981 Research project Solar One, Mojave Desert, California:
10 MW- Solar tower power plant
1980 201020052000199519901985
Source: solarserver.com
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2. History Modern times
1984: Kramer junction, Mojave Desert, California:
14 MW- First commercial CSP with parabolic trough
Expansion until today: 354 MW
Source: dlr.de
1980 201020052000199519901985
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2. History Modern times
1997 Almera: 10 kWel- Dish-Stirling Pilot plant
1999 Solar Two (retrofit of Solar One)
Source: theirearth.com
1980 201020052000199519901985
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2. History Modern times
2006 Andalusia: Commencement of Andasol 1:
First CSP in Europe with 50 MWel in operation since 2008
Source: Solar Millennium
1980 201020052000199519901985
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2. History Modern times
2008: Egypt: Construction start of first CSP in Africa with 50 MWel
2009: Establishment of the DESERTEC Foundation
1980 201020052000199519901985
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2. History Current Situation
2011, about 1.17 GWel of CSP power is installed worldwide: 582
MWel are in Spain, 507 MWel in the U.S
17 GWel of CSP projects are currently being planned worldwide:
8 GWel in USA, 4.5 GWel in Spain, 2.5 GWel in China
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3. Physics and thermodynamics
Radiation: Photon
Photon (derived from Greek: phs - "Light") is an elementary
excitation of the quantized electromagnetic field
It exhibits properties of both waves and particles
Wave-particle duality
Photons are massless (m = 0 kg)
Photons move at the speed of light
In vacuum this is 300 000 21
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3. Physics and thermodynamics
Radiation:
All wavelengths have the same propagation speed, in vacuum =
=
Planck's constant describes the relationship between energy and
frequency of a photon
Energy of an photon:
=
Planck's constant =6.636 10
The shorter the wavelength (or higher the frequency), the greater is
the Energy of the photon
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Wavelength Frequency
Period []
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3. Physics and thermodynamics
Radiation: Spectrum
Source: Incropera, DeWitt
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Absorption Reflection Transmission Emission
The absorption
coefficient
indicates
how much radiation is
absorbed
The reflectance
indicates the
relationship between
incident and reflected
radiation
The degree of
transmission
indicates the
relationship between
incident and
transmitted radiation
The emissivity
indicates how much
radiation is emitted by
the body
The value of variesbetween 0 and 1
The value of varies
between 0 and 1
The value ofvariesbetween 0 and 1
The value ofvariesbetween 0 and 1.
The darker the body,
the higher the degree
of absorption
Reflectance is strongly
dependent on the
material
Transmittance is
strongly dependent on
the material
For
mirrors = 0 and for anideal black body = 1
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3. Physics and thermodynamics
Interaction of radiation with matter: Reflection
Law of reflection: Angle of incidence is equal the angle of reflection
=
Both angles along with the normal of the mirror lie in the same
plane
Incident ray Reflected ray
Mirror
Normal
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3. Physics and thermodynamics
Black Body
An ideal black body absorbs all incoming radiation completely and
emits with a specific maximum intensity
The spectrum of radiation emitted by a black body depends solely
on its temperature
Absorptance = 1Emissivity = 1Reflectance
= 0
Transmissivity = 0
The sun is very close to being an ideal black body
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3. Physics and thermodynamics
Planck's law
=
1
where
=2 =3.7410 / = / = 1. 4410
= 1 . 3 8 1 0 (Boltzmann Constant)Temperature of the radiating surface T
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3. Physics and thermodynamics
Planck's law The wavelength of
maximum intensity
decreases with increasing
temperature
The higher the temperature,
the higher is this maximum
intensity
Source: Wikipedia
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Wavelength in m
Plancks radiation spectrum
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3. Physics and thermodynamics
Stefan-Boltzmann law (Josef Stefan and Ludwig Boltzmann)
Specifies the thermal power emitted by an ideal black body as a
function of its temperature
= Radiation []Stefan-Boltzmann-Constant = 5 . 6 7 1 0 Surface area of the body Absolute Temperature
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3. Physics and thermodynamics
Stefan-Boltzmann law (Josef Stefan and Ludwig Boltzmann)
For a non-black body, the following equation applies:
= With the weighted average of the emissivity over the wavelengths
()
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3. Physics and thermodynamics
The Sun: General data
Almost spherical radiating source
Diameter: =1.39210 km Surface temperature: approx. 5777 K
Core Temperature: 15 Million K
The Earth: General data
Almost spherical
Diameter: =1.27110 km Surface temperature: 390 K(-89.6 CAntarctic +58 C Libya)
Core Temperature :
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3. Physics and thermodynamics
1/r Inverse square law for energy quantities (Solar Radiation)
Surface Power Density [W/m]
= =
1/r Inverse distance law for linear field quantities
(Acoustic quantities)
Sound pressure, Sound velocity, Sound deflection
Source: wikipedia
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3. Physics and thermodynamics
The Sun: Solar constant
The amount ofradiation that reaches the earths atmosphere
= 1 3 6 0
The actual density of the radiation outside the Earth's atmosphere
determines the average solar constant . It was standardised bythe World Meteorological Organization in 1982:
=1367 7
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3. Physics and thermodynamics
The Sun: Solar constant
Comparison between
spectral irradiance of solar
radiation(solid line) andblack body(dashed line)
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Wavelength in m
SpectralRadiance
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3. Physics and thermodynamics
The Sun: Global radiation
The radiation that actually arrives on a horizontal surface on Earth
Direct solar radiation and diffused radiation
Is dependent on severe weather fluctuations
For CSP, only the direct radiation can be concentrated with opticalmethods
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3. Physics and thermodynamics Atmosphere
Ozone (20-40 km) 0.5-3%
Upper Dust Layer (15-25 km) 1-5%
Air Molecules (0-30 km) 6-8%
Water Vapour (0-3 km) 3-9%
Lower Dust(0-3 km) 0.5-5%
0.6-4%
4%
0.4-4%
0.4-14%
Solar Radiation 1367 W/m
Direct to Earth
33-83 %
Diffuse Insolation
5-26 %
Absorbed(Lost)11-30 % Scattered into space (Lost) 1.6-11 %
Source: www.powerfromthesun.net
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3. Physics and thermodynamics Atmosphere
Spectral transmittances through the atmosphere
Factors influencing attenuation of solar radiation:
= , , , , ,
1. ,: Rayleigh Scattering by Molecules2. ,: Absorption by aerosols3. ,: Absorption by ozone4. ,: Absorption by Water Vapor5. , : Absorption by air
Source: Baehr, Stephan: Wrme- und Stoffbertragung
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3. Physics and thermodynamics Atmosphere
Sun: Intensity of Radiation
Source: renewable-energy-concepts.com
1,2,3
3 4,54
4,5
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4
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3. Physics and thermodynamics diurnal variations
Sun: Azimuth Angle
Deviation from the
southern orientationtowards East or West
Source: alternative-energiequellen.comAzimuth Angle
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3. Physics and thermodynamics diurnal variations
Sun: Angle of inclination
Deviation from the horizontal axis
Angle of inclination
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3. Physics and thermodynamics diurnal variations
The Sun: Azimuth and inclination
For the optimal yield of a solar system, the absorber should always
be adjusted to the Sun.
The Azimuth angle and the angle of inclination should be adapted
to the diurnal course of the Sun
For non-trackable absorber in Germany, the ideal Azimuth angle is0(South) and angle of inclination is 35
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4. Measurements and solar potential
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Pyranometer - Principle
Source: www.powerfromthesun.net
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4. Measurements and solar potential
Global solar radiation (all the incoming solar radiation received from
above by a surface horizontal to the ground)
)
Source: meteonorm.com
Germany1200 kWh/m2aAmerica
2200 kWh/m2aSahara
2500 kWh/m2a
Spain2000 kWh/m2a
Australia2500 kWh/m2a
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4. Measurements and solar potential
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Direct solar radiation
Germany
1000 kWh/m2aAmerica
2700 kWh/m2aSahara
3100 kWh/m2a
Spain
2200 kWh/m2a
Australia2800 kWh/m2a
Source: meteonorm.com
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4. Measurements and solar potential