Solar power plant

The Need

Rising electricity demand

Rapidly depleting fossil fuel reserves

Global Warming

Rising fuel imports – Loss to exchequer

Huge solar energy potential

1878- First Solar Power System Developed in France to Produce Steam to Drive Machinery

History of solar energy developments

Solar Printing Press Invented by August

Mouchat: 1878

A: Solar Collector

B: Steam Engine

C: Water Tank

Printing Press turned

By steam engine

a) Solar steam engine, Paris,1878

b) Solar steam engine, California,1901

c) Solar steam engine with flat-plate collector, Pennsylvania, 1901,1911

d) Solar steam engine, Cairo,Egypt,1913

History of solar energy developments cont…

Solar Radiation Fundamentals

Planets of the Solar System

Sun - Earth Features

Radiant energy output : 3.94 x 1026 W

Radius of the Sun : 6.960 x 108 m

Mean sun–earth distance : 149.6 x 106 Km

Radius of the Earth : 6.378 x 106 m

Energy intercepted by Earth : 1.8 x 1017 W

Solar constant : 1353 Wm-2

Solar energy is produced at the core of the

sun by nuclear fusion

The Earth's surface moves at the equator at a speed of about 467 m per second

Earth’s Rotation and Revolution

The Earth’s rotational axis is tilted 23.5° from the red line drawn perpendicular to the

ecliptic plane. This tilt remains the same anywhere along the Earth’s orbit around the

Sun. Seasons are appropriate only for the Northern Hemisphere.

Earth’s Rotational Axis Around the Sun Over the Year

Earth's axis at 0°

Late June: Northern Hemisphere

summer, Southern Hemisphere winter

Late December: Northern Hemisphere

winter, Southern Hemisphere summer

Shape of the Earth’s Orbit around the Sun

Earth’s Orbit around the Sun

During the June solstice the Earth's North Pole is tilted 23.5 degrees towards the Sun relative

to the circle of illumination. This phenomenon keeps all places above a latitude of 66.5

degrees N in 24 hours of sunlight, while locations below a latitude of 66.5 degrees S are in

darkness. The North Pole is tilted 23.5 degrees away from the Sun relative to the circle of

illumination during the December solstice. On this date, all places above a latitude of 66.5

degrees N are now in darkness, while locations below a latitude of 66.5 degrees S receive 24

hours of daylight.

Earth’s Rotational Axis Around the Sun Over the Year – Contd…

During the equinoxes, the axis of the Earth is not tilted toward or away from the Sun and

the circle of illumination cuts through the poles. This situation does not suggest that the

23.5 degree tilt of the Earth no longer exists.

Earth’s Rotational Axis Around the Sun Over the Year – Contd…

Annual variations in day length for locations

at the equator, 30°, 50°, 60°, and 70° North latitude

Annual Variations in Day Length

Solar Radiation Budget

The radiation from the Sun, travels in the space as electromagnetic wave

The Earth receives 1.8 x 1017 W of incoming solar radiation continuously at top of its

atmosphere.

But only half of it reaches the earths’ surface.

Absorption, scattering and reflection of light during its passage through the

atmosphere are responsible for reduction of the amount of solar radiation available on

the earth’s surface

Solar energy is by nature, a low density energy source

Above the earth’s atmosphere, sunlight carries 1353 W/m2

Solar Constant

Solar constant as the amount of solar radiation received outside the earth’s atmosphere

on a unit area perpendicular to the rays of the sun, at the mean distance of the earth

from the sun.

Extraterrestrial Solar Radiation

The earth’s orbit is slightly elliptical, the intensity of solar radiation received outside the earth’s

atmosphere varies slightly from constant value by ±3.4 percent

3601 0.034cos

365.25o sc

NI I

Io = Extraterrestrial solar radiation outside

the earth’s atmosphere

N = nth day of the year

Concept of Extraterrestrial

Horizontal Irradiance

Io,h = Io Cosθz

Extraterrestrial solar radiation falling on a surface

parallel to the ground is

Isc = Solar constant, is the rate at which energy

received from the sun on a unit area perpendicular

to the rays of the sun at mean distance of the earth

from sun

Isc=1353 W/m2

Terrestrial Solar Radiation

Solar radiation falling on the earth surface is called terrestrial radiation

Terrestrial radiation varies because-

-Daily due to Earth rotation

-Seasonally due to changes in the sun declination angle

-Other effects due to presence of the various gases, vapors and particulate

matter in the earth atmosphere

The extraterrestrial radiation is attenuated by: Scattering and absorption

Scattering: a mechanism by which the part of radiation scattered laterally by air

molecules, water vapor, and dust in the atmosphere

Depends upon: scattering medium and wavelength of the radiation

Absorption: Absorption of solar radiation in the atmosphere is mainly by

- ozone O3 (-ultraviolet- short wavelength below 0.29 μm)

- water vapor H2O (Infrared- longer wavelength of spectrum at 1.0,1.4 and 1.8

μm and

- Carbon dioxide CO2 ( spectrum of 2.36 to 3.02 μm , 4.01 to 4.08 μm and

12.5 to 16.5 μm

Nominal range of clear sky

absorption and scattering of

incident solar energy

Terrestrial Solar Irradiance – Contd…

Terrestrial Solar Radiation

Solar radiation passes through the earth's atmosphere, is composed of two parts

beam and diffused radiation

Beam Radiation

Beam radiation is the solar radiation propagating along the line joining the

receiving surface and the sun

Diffuse Radiation

It is the solar radiation scattered by aerosols, dust and air molecules. It does

not have unique direction

The solar radiation received from the sun after under going scattering by the

atmosphere is known as diffuse radiation

Global Radiation

It is the sum of beam and diffuse radiation

Terrestrial Solar Radiation

Air mass (ma) : ratio of the optical thickness of the atmosphere through which

beam radiation passes to the surface to its optical thickness if

the sun were at zenith i.e direct above

ma= 0 mean extraterrestrial

ma= 1 when sun is at zenith

ma= 2 for zenith angle θz= 60o

The air mass ma is related to zenith angle

θz= 0o to θz= 70o , at sea level , by

ma= (cosθz)-1

Clearness index (Ci) : ratio of the average radiation on a horizontal surface for given

period to the average extraterrestrial radiation for same period

The averaging could be monthly, daily or hourly,

Ci would be monthly, daily or hourly clearness index

Ci varies from 30 to as high as 70 %, in some places it is zero because of bad weather

Radiation Terminology

Irradiance

The rate at which radiant energy is incident on a surface per unit area of the surface

Irradiation

The incident energy per unit area on a surface found by integration of irradiance over a

specified time, usually an hour or a day

Radiosity

The rate at which radiant energy leaves a surface per unit area, by combined emission,

reflection and transmission

Emissive Power

The rate at which radiant energy leaves a surface per unit area, by emission only

Earth Albedo

The earth reflects about 30% of all incoming solar radiation back to extraterrestrial region

through atmosphere

Parameter Instruments used

Direct solar irradiance Pyrheliometers

Global solar irradiance Pyranometer

Diffuse solar irradiance Pyranometer with shading ring

Duration of brightness Sunshine recorder

Radiation Measurements

1. Thermopile sensor 2, 3. Glass domes 4. Radiation screen

5. Signal cable 6. Gland 7. Leveling feet

8. Printed circuit board 9. Desiccant 10, 11. Level

Pyranometer – Global & Diffuse Radiation

Measures solar irradiance from 300-4000 nm

Sensor: Blackened copper constantan thermopile covered with two concentric glass

domes which are transparent to radiation from 300-4000 nm.

Generated EMF (electromotive force) by thermopile is proportional to incident

radiation.

Used for instantaneous measurement and continuous recording of Global, Diffused,

Reflected Solar irradiance.

Pyranometer – Global & Diffuse Radiation

Pyrheliometer – Beam Radiation

Measures direct solar irradiance from 300-4000 nm at normal incidence.

Sensor: Blackened copper constantan thermopile.

Sensor mounted in a long metallic tube to collimate the incident beam.

Solar tracker maintains the pyrheliometer always directed towards the sun.

Generated emf by the thermopile is proportional to incident irradiance

Used for instantaneous measurements and continuous recording of direct solar irradiance.

Pyrheliometer – Beam Radiation

Sunshine Recorder

Invented by John Francis Campbell in 1853 and later modified in 1879 by George

Gabriel Stokes

Campbell-Stokes recorder adapted for use in

polar regions

Campbell-Stokes recorder used in a Tropical region

Sunshine card for the Campbell-Stokes recorder

Nature of the solar resource

Nature of the solar resource

Sun-Earth Angles

Latitude (Ф)

The latitude of the location is the angle made by the radial line, joining the given

location to the centre of the earth, with its projection on the equatorial plane.

Declination ( )

The declination is the between the earth’s axis of rotation and the surface of a cylinder

through the earth’s orbit

= Declination

n = day number (number of

days since 1st January)

28423.45sin 360

365

n

It is defined as the angular displacement of the sun east or west of

the local meridian, due to the rotation of the earth on its axis at 15o

per hour.

W = (ST-12) x 15

ST = Local solar time

Hour Angle (w)

Nature of the solar resource

Sun-Earth Angles- Hour Angle

Nature of the solar resource

Sun-Earth Angles

z

s

s

N

S E

W

Zenith

Nature of the solar resource

Sun-Earth Angles

Zenith angle (z ): the angle between the vertical (zenith) and the line of the sun

Solar attitude angle (as): the angle between the horizontal and the line to the sun

Solar azimuth angle (s ) :the angle of the projection of beam radiation on the horizontal plane (with

zero due south, east negative and west positive)

z

s

s

N

S E

W

Zenith

Z = Zenith Angle

= Latitude

= Declination

w = Hour angle

s = Solar azimuth

angle

s = Solar attitude

angle

Nature of the solar resource

Sun-Earth Angles

cos cos cos cos sin sinz w

sin cos cos sin sincos

coss

s

w

Note:

& w should be the same sign

z

s

s

N

S E

W

Zenith

ws = Sunset angle

= Declination

= Latitude

Note:

Day length is in hours

Nature of the solar resource

Solar geometry: Sun angles: Sunset angle and day length

cos tan tansw

12Day length cos tan tan

15

Nature of the solar resource

Solar geometry: Collector angles

z

s

s

N

S E

W

Zenith

Slope: The angle between the plane of the collector and the horizontal

Surface azimuth angle: The deviation of the projection on a horizontal plane of the normal to the

collector from the local meridian (with zero due south, east negative and west positive)

Angle of incidence : The angle between the beam radiation on the collector and the normal

Nature of the solar resource

Solar geometry: Collector angles

cos sin sin cos cos sin cos

cos cos cos cos sin sin cos

cos sin sin sin

w

w

= Angle of incidence

= Surface azimuth

angle

= Collector slope

= Declination

= Latitude

w = Hour angle

Incident angles

z

s

s

N

South E

W

Zenith

Empirical Equations for Predicting the Availability of Solar Radiation

Monthly Average Daily Global Radiation

max

g

c

H Sa b

H S

gH

cH

S

maxS

a, b Constants obtained by fitting data

Monthly average of the daily global radiation on a horizontal surface at a location (kJ/m2-day)

Monthly average of the daily global radiation on a horizontal surface at the same location on a clear day (kJ/m2-day)

Monthly average of sunshine hours per day at the location (h)

Monthly average of the maximum possible sunshine hours per day at the location (h)

max

g

c

H Sa b

H S

In above equation Hc is replaced by Ho

Empirical Equations for Predicting the Availability of Solar Radiation

Monthly Average Daily Global Radiation

3601 0.034cos

365.25o sc

NI I

Empirical Equations for Predicting the Availability of Solar Radiation

Monthly Average Hourly Global Radiation

0

cosg o

g

IIa b w

H H

gI

oI

a 0.409+0.5016 sin(ws-60o)

b 0.6609 – 0.4767 sin(ws-60o)

Monthly average of the hourly extra-terrestrial radiation on a horizontal surface (kJ/m2h)

Monthly average of the hourly global radiation on a horizontal surface (kJ/m2-h)

– Contd…

Sun-Earth Angles – Contd…

Tilt Factor or Geometric Factor (R)

It is defined as the ratio of radiation flux on a tilted surface to that radiation flux falling on a

horizontal surface

BIR

I

IB Radiation at tilted surface

I radiation at horizontal surface

1 cos 1 cos

.2 2

B b b d b d gI I R I I I

bBb

b

IR

I dB

d

d

IR

I

where

z

s

s

N

S E

W

Zenith

Solar-electric conversion systems

Solar energy may be converted to electricity by one of the means:

Solar thermal conversion or photovoltaic conversion

Solar Thermal Conversion

Solar thermal

collector/

concentrator and

receiver

Hot

working

fluid

Thermal Energy

Storage system

Heating/cooling

application

Power

generation

Fluid let off

(Open Cycle)

Circulation of condensed working

fluid (Closed loop)

Radiation from SUN

Typical Solar Thermal Power Plant

Similar to a steam power plant without the “fossil-fuel” boiler

Solar Thermal

Gathering Array

Cooling Tower

Steam

Turbine Electric

Generator

Condenser

High Pressure

Pump

Hotwell

To Grid

Cooling

Water

Steam

Dryer

Water

Steam

Steam

Sun

The Rankine cycle uses a liquid that evaporates when heated and

expands to produce work, such as turning a turbine, which when

connected to a generator, produces electricity

The working fluid most commonly used is water, though other

liquids can also be used

Options to integrate solar energy into the power plant cycle:

- Steam Rankine cycle

- Organic Rankine cycle

- Brayton cycle

- Combined cycle

-Repowering systems

Power Plant Cycle

Types of Solar Thermal Power Plants

Concentrating type

Line Focusing

- Parabolic Trough

- Compact Linear Fresnel Reflector

Point Focusing

- Dish Stirling Systems / Concentrating Dish

- Solar Tower Plants using Central Receiver

Non-concentrating type

- Solar Updraft Tower: Solar Chimney

- Solar Pond

Central Receiver Solar Thermal Power Plants

Components

Heliostat

Tower

Central receiver

Turbine-generator

Storage

Condenser

Cooling tower

Central receiver has a circular field array of heliostats to focus sunlight on to a

central receiver mounted on top of a tower.

Hot salt Cold salt

Heliostat

Conventional EPGS

Hot fluid

Cold fluid

Central Receiver

Heliostat

Heliostat composed:

Reflecting surface or mirror

Mirror support structure

Pedestal

Foundation

Control and drive mechanism

Heliostat Field

Energy losses

Shadowing

Blocking

Reflective loss

Attenuation

Cosine loss

Types of field

Surrounded field

North field

Cosine Losses of Heliostat Field

Reflecting surface of the heliostat is not perpendicular to the beam radiation

Area of the solar flux intercepted by the heliostat is less than by cosine of the angle

between the surface and the perpendicular to the beam

Sun rays

Sun rays

Receiver

Surface normal z

r

B A

South field North field

Heliostat B Heliostat A

Heliostat Field

Receiver

Losses

Spillage

Reflection

Convection

Radiation

Conduction

Solar Thermal Power Solar Thermal Energy

PS10 and PS20 solar power tower (HFC)

(Seville, Spain). 2007 and 2009

Solar Power Tower One and Two

Solar Parabolic Dish Collector

Principle of Solar Parabolic Dish Collector

Solar parabolic dish collector is a Three dimensional (3-D) collector.

Array of parabolic mirrors focus solar radiation on to the receiver.

Fluid in the receiver is heated up to 1500oC and it is used to generate the electricity.

The engine under consideration include Stirling and Brayton cycle engines.

Parabolic Dish Collector

Solar Radiation heats fluid medium or drives chemical reaction

Features Solar Parabolic Dish Technology

Mature and Cost Effective Technology: Large utility projects using parabolic dishes are now

under development.

Technical Challenges

Development of solar materials and components

Commercial availability of a solar Stirling engine

Advantages

Demonstrated highest solar-to-electric conversion efficiency

Modular - may be deployed individually for remote applications or grouped together

for small-grid (village power) systems.

Solar dish-engine systems are being developed for use in emerging global markets for distributed

generation, green power, remote power, and grid-connected applications.

Individual units, ranging in size from 9 to 25 kilowatts, can operate independent of power grids in

remote sunny locations to pump water or to provide electricity for people living in remote areas.

Largely because of their high efficiency and “conventional” construction, the cost of dish-engine

systems is expected to compete in distributed markets.

Parabolic Dish Collector System at Sandia National Laboratory

http://internationalrivers.org/files/images/solar_thermal_web.jpg

Solar Parabolic Trough Collector

Principles of Solar Parabolic Trough Collector

Parabolic trough collector has a linear parabolic-shaped reflector that focuses the sun’s direct

beam radiation on a linear receiver located at the focus of the parabola.

The collectors track the sun from east to west during the day

Heat transfer fluid is circulated through the receiver and returns to a series of heat exchangers

in the power block where the fluid is used to generate high-pressure superheated steam.

The superheated steam is then fed to a conventional reheat steam turbine/generator to produce

electricity.

Parabolic Trough (Contd..)

Parabolic Trough (Contd..)

High optical and tracking accuracy

Low heat losses

Manufacturing simplicity

Reduced weight and cost

Increased torsional and bending stiffness under wind loads

Reduced number of parts

Corrosion resistance

More compact transport methods

Reduced field erection costs, without loss of optical accuracy

Increased aperture area (reduced drive, control and power requirements per unit

reflector area)

Features of Solar Parabolic Trough Collector

The Rankine cycle system uses a liquid that evaporates when heated and expands to

produce work, such as turning a turbine, which when connected to a generator, produces

electricity.

The working fluid most commonly used as water, though other liquids can also be used

Number of Rankine power cycles can be used for parabolic trough power plants and

there are a number of options for how to integrate solar energy into the power cycle.

Steam Rankine cycle

Organic Rankine cycle

Combined cycle

Power Cycle

Steam Rankine Cycle

The SEGS (solar electric generating system) plants and most new projects are planning

to use steam Rankine power cycles. These power plants have power cycles very similar

to those used for coal, nuclear, and natural gas-fired steam power plants.

The 80-MWe SEGS plants use a regenerative reheat steam turbine cycle that has a gross

steam cycle efficiency approaching 38% with high-pressure steam conditions of 100bar,

and 370°C.

The power cycle uses a solar steam generator in place of the conventional boiler

The power cycle also consists of

- A surface condenser

- Feed water heaters

- Deaerator

- Cooling towers

Solar energy is used to generate the high-pressure steam and also to reheat the steam

The solar field supplies the hot heat transfer fluid (HTF) to the power plant

The heat transfer fluid passes through a series of shell-in-tube heat exchangers

to generate the high-pressure steam that runs the Rankine steam turbine.

The cold heat transfer fluid is then returned to the solar field.

Steam Rankine cycle

1

2 3

4 1

Direct Steam Generation

The parabolic trough plants can generate steam directly in the solar field.

This eliminates the need for an intermediate heat transfer fluid and steam generation heat

exchangers.

It will allow the solar field to operate at higher temperatures, resulting in higher power

cycle efficiencies

The direct steam generation is still one of the most promising opportunities for future cost

reductions.

Control Scheme for Direct Steam Generation

Once through concept

Recirculation concept

Injection concept

In direct steam generation the changes in the inlet water conditions and/or solar radiation

will only affect the amount and quality of steam produced by the solar field.

Control Scheme for Direct Steam Generation – Contd…

Different Control Scheme for Direct steam generation

Once through mode

The main disadvantages is, the controllability of the superheated steam parameters at the

collector field outlet

Recirculation mode

The measurement system necessary to assist the control scheme

Injection mode

The amount of water fed at the inlet of the evaporator is greater than the amount

that can be evaporated.

The steam produced is separated from the water by the middle separator and is

fed into the inlet of the super heater section.

This type of DSG system is highly controllable

The middle water–steam separator and the water recirculation pump increase the

system load.

Parabolic Trough -Contd..

Solar Thermal Energy

Solar Thermal Power

Andasol solar power station (PTC)

(Granada, Spain), 2009

Puertollano solar power station (PTC)

(Ciudad real, Spain), 2009

Linear Fresnel Reflector (LFR)

Linear Fresnel Reflector (LFR) is a single-axis tracking technology that focuses sunlight reflected by

long heliostats onto a linear receiver to convert solar energy to heat , using array of mirror strips

close to the ground to direct solar radiation to a single, linear, elevated, fixed receiver

Linear Fresnel Reflector (LFR)

Features of Compact Linear Fresnel Reflector

Inexpensive planar mirrors and simple tracking system

Fixed absorber tube with no need for flexible high pressure joints or thermal expansion

bellows

No vacuum technology and no metal-to-glass sealing

Wind loads are substantially reduced on the reflector strips, so the reflector width for one

absorber tube can be up to three times the width of parabolic troughs

Efficient use of land since the collectors can be placed close to one another

It weighs as little as 3 kg per sq meter, 30% of the weight of the parabolic trough mirror

Technical Details of Liddell Power Plant The reflector rows are 600 m long and 1.6 m wide, and composed of reflector space frame

modules that are 10 m long

Excellent ground utilisation is achieved with at least 62% ground coverage

The towers are 7.5 m high at the receiver aperture

The array uses flat or curved reflectors instead of costly sagged glass reflectors

The reflectors are of low cost 3mm mirrored glass, with a reflectance of 0.83 and are mounted close to the ground

Low cost demineralised water is used as the heat transfer fluid

Liddell CLFR system will provide 95 MW of thermal energy to the power plant, giving an estimated electrical equivalent of 35 MWe

Prototype array Receiver with tubes

Liddell Power Plant – Different Views

Solar Thermal Power

Solar Thermal Energy

Calasparra solar power plant (LFR)

(Murcia, Spain) 2009.

Solar Thermal Power

Types of solar thermal power plant

Technology roadmap concentrating solar power, IEA, 2010.

Solar pond

Non-concentrating Solar Thermal Power Plants

92 Non-concentrating Solar Thermal Power Plants

Solar Pond

Non-concentrating Solar Thermal Power Plants

Solar Pond (Contd..)

A Solar Pond collects solar energy by absorbing both the direct and

diffuse components of sunlight

A solar pond is a reservoir of salty water that stores solar heat and uses

this heat for power generation or other applications

Solar pond contains salt in high concentrations near the bottom, with

significantly diminishing concentrations near the surface. This salt-

density gradient is obtained by perfectly dissolving heavy salt with the

increasing depth to suppress the natural tendency for heated fluid to rise

to the surface and lose its heat to the atmosphere by evaporation,

convection, and radiation

The density gradient permits heated fluid to remain in the bottom layers of

the pond while the surface layers are sufficient to drive the vapour

generator of an organic Rankine-cycle engine, to provide process heat and

to desalt water temperatures of about 90°C are commonly attained in the

pond bottom

Non-concentrating Solar Thermal Power Plants

Solar Pond (Contd..)

Solar Pond (Contd..)

nmas

Solar Pond (Contd..)

Solar Pond (Contd..)

Operating difficulties

Effect of the diffusion on concentration profile

Surface layer flow and lower layer flow

Wind induced wave

Biological growth

Fouling due dirt and leaves

Solar Chimney

Non-concentrating Solar Thermal Power Plants

Non-concentrating Solar Thermal Power Plants

Solar Chimney

Non-concentrating Solar Thermal Power Plants

Solar Chimney (Contd..)

A solar chimney power plant has a long tower, with a height of up to 1000 m,

and this is surrounded by a large collector roof, up to 130 m in diameter, that

consists of glass or resistive plastic supported on a framework

The sun heats up the ground and the air underneath the collector roof, and the

heated air follows the upward incline of the roof until it reaches the chimney

Heated air flows at high speed through the chimney and drives wind generators

at its bottom

The ground under the collector roof behaves as a storage medium, and can even

heat up the air for a significant time after sunset

The efficiency of the solar chimney power plant is below 2%, and depends

mainly on the height of the tower, and so these power plants can only be

constructed on land which is very cheap or free

Working principles of Solar Chimney

Transparent roof, which admits the short wave solar radiation component and retains long-wave radiation from the heated ground.

Thus, when solar radiation pass through the transparent roof it is absorbed by the ground elements and it converts into heat energy.

Transparent roof

•Since air is heated, it starts to

rise up and move towards to

chimney,seen in fıgure 11.

Also, it gains velocity.

•Heated air enters the chimney

placed at the center of the roof

and creates an up draught there.

•Inside the chimney, turbines

with electric generator, produce

electricity .

Working principles of Solar Chimney

Prototype of the solar chimney at Manzanares.

chimney 195 m high

and 10 m in diameter

surrounded by a collector 240 m

in diameter.

Heat Output

Collector Area Solar Radiation

Specific heat

capacity of the air

Mass flow

Collector Efficiency

The temperature

differences between the

collector and out flow

Air speed at collector

outflow Specific density of air at

temperature To + ΔT at collector

outflow

Chimney cross-section area

The sheet metal was only 1.5mm

thick

150m high

10m diameter

The sheets were abuted vertically at

intervals of 8.6m and shiftened every

4m by exterior trussrirelers

Solar Chimney Prototype at Manzanares (Spain)

Solar Chimney Prototype at Manzanares

Solar Chimney (Contd..)

Non-concentrating Solar Thermal Power Plants

Solar Radiation Budget – Contd…