Faculty of Engineering, Architecture and Science

Department of Mechanical Engineering

Electrical Systems for Buildings

SOLAR TECHNOLOGIES AS AN ALTERNATIVE

SOURCE OF ENERGY

STUDENT: JULIA KONNOVA 2014

1

Executive Summary

The purpose of the following report was investigation of the potential of solar technologies as an

alternative source of energy. The covered topics included overview of the following areas:

- Conventional Photovoltaic Systems - Utilization solar energy for heat storage purposes - Industrial application of solar technologies - Hybrid Systems implementing double function of utilizing both heat and light energy - Experimental technologies of conversion heat and light into electricity - Nanotechnologies improving performance of conventional PV systems - New technologies of transparent photovoltaic cells based on absorbing infrared light - Applications in different fields, appliances and devices.

The investigation of solar technologies amazed by the multipurpose and variety of implementation in different fields, such as:

- Urban design, - Architecture from a small residence to communities and iconic buildings, - Industry and transportation.

The benefits of pure, green energy that can satisfy our needs without destroying the planet are support by easy maintenance and long life of the devices (25-30 years for PV cells), financial savings on household bills. Solar technology is not anymore only alternative green technology; it is free and renewable source of energy competitive with conventional oil based systems nowadays and able to replace them in near future.

2

Table of content

Executive Summary 1

Introduction 3

Solar Electricity. Conventional Photovoltaic Power 4

Heat Storage & Water Hating System 6

Types of solar water heating systems 7

Flat-Plate collector. Evacuated-tube solar collectors 8

Integral collector-storage system. Solar Power Tower 9

Solar reflectors. Location 10

Solar Wall PV/Thermal Hybrid System 11

SolarDuct. SolarWall 12

Solar Energy Conversion Process: Light and Heat. Nanotechnology 13

Solar Thermal Cooling 14

Transparent Polymer Solar Cell. Organic Solar Cells or Photovoltaic Cells (OPVs) 15

Manufacturing process and Cost. Principle of work. Application 16

Challenges 17

Conclusion 18

References 19

Appendix

1. Implementation of hybrid Solar Wall & Duct PV/T systems within building structure. 20

2. Schematic Comparison of Rigid Crystalline Silicon to a Flexible Organic Solar Cell 21 3. Scheme of working process of Solar Power Tower 22

4. Implementation of solar technologies in different fields 23 5. Solar Panel Awnings and Roof Shingles 24

3

Introduction

According to some research, Buildings take up 40% of the global energy demand, and that

number will reach soon 60%. It is about 41% of energy use, 73% of electricity consumption and

38% of all CO2 emissions. Integration of the alternate green technologies is the way to combat

this in the future. According to Armonk, N.Y.-based IBM, employing a smart building strategy

can help reduce energy use by up to 50 percent and increase facilities utilization by up to 85

percent. Technologies based on utilization of the solar radiation are one of the emerging and

most promising in the world these days. [16]

The earth receives about one-half of one-billionth the sun’s energy output. It would meet the

energy of the entire world, if convert less than 0.1% of this solar radiation into electricity. Solar

radiation can be collected, stored and used in buildings and building systems to provide heat,

power and even cooling. [1]

The advantages of utilization solar power are following but not limited:

- Generates free energy from the sun - Has no moving parts to break down and as a result required minimum maintenance - Long life and durability of the systems (up to 30 years) - No noise, exhaust or emit - Storage and utilizing power during blackouts - Opportunity and cost-effectiveness the use of electricity in remote areas where it would

be expensive or impossible to run power lines - Non-polluting energy reduces emissions: Has no direct impact on the environment - Minimizing costs of energy consumption. [11]

Variety of applications, advantages and challenges of implementation solar technologies, as well as latest tendencies and researches were discussed further in the report.

4

Solar Electricity. Conventional Photovoltaic Power

Photovoltaic technology converts sunlight into electricity. It has numerous environmental and

economic benefits with proven reliability.

The sunlight is a free, pure and abundant renewable source of energy that Earth receives

enough quantity every day. It does not produce air pollution or hazardous waste and does not

require any fuel to be transported or combusted. The electricity can be stored and the

applications are widespread.

The initial component of

the system is a

photovoltaic cell. It is

constructed of

semiconducting material,

usually silicon. Absorbing

the sunlight, electrons in

semiconducting material

move, producing a flow of

electrical current. The

photons that compose the

solar radiation contain

energy. PV cell absorbs

photons, energy of which is

then transferred to an

electron in the

semiconducting material.

This supplementary energy

enforces the electron to

jump to a higher orbit and

jump from atom to atom. A

permanent electric field built into the cell forced electron movement in a specific direction: out of

the cell, through an electrical circuit, and back to the other side of the cell. The electron flow

causes the electricity. [1]

This electricity (direct current) can be used then by appliances or converted into Alternate

current and enter the utility grid.

Typical PV cell consists of the following elements:

- Waterproofing glass cover

- Antireflective layer to keep sunlight from reflecting away from the cell

- Top metallic grid – operates as contact to allow the electrons to enter the circuit

- Back contact layer to allow the electron complete the circuit.

The scheme demonstrates the circle how PV cells are formed into a Module of numerous cells.

Modules are constructed into a Solar Panel, a quantity of which forms Solar Array. However, for

the performance of Solar Panels as a Building-Integrated PV (BIPV) that generates electricity,

the whole system of other components is required.

5

Major System Components

The photovoltaic system consists of

the following modules:

– Solar panel

- Inverter

- Charger

- Batteries

The PV modules generate Direct

Current (DC) that through inverter

changes into Alternating Current (AC).

The AC provided the electricity at the

appropriate voltage and frequency to

feed with the power all home appliances, lights etc. The batteries able to store the energy

produced by PV panels and distribute it back when a demand arises. They are recharging each

day to maintain battery charge. Charge controller prevents battery overcharging and prolongs a

long life of the battery.

Types of PV Systems

PV systems classified according to functional and operating requirements, components

configuration, connection to other power sources and appliances. The most common

classifications are further investigated.

Grid connected (GTS) – systems designed to

operate in parallel with the electric utility grid. The

AC power supplied to the utility by the inverter,

which automatically stops supplying power to the

grid when the utility grid is not energized.

Stand Alone System – are designed to operate

independent of the electric utility grid. They may be

powered only by PV array or combined in hybrid

systems with wind, an engine-generator or utility

power as a backup power source. The simplest

type of a stand-alone system is direct-coupled,

when DC output of PV module is directly

……………………………………………………connected to a load that uses direct current. There

is no battery in this system, so it operates only

during sunlight hours. This system is suitable for

applications as ventilation fans, water pumps or for

………..solar thermal water heating pumps.

System with battery can be both – stand alone and

grid–tie (GTB). The battery stores power for use

during night or blackouts.

6

Hybrid Systems in addition to the battery

use a wind, engine-generator or utility

power to backup power source. [1, 11]

Hybrid power systems can be more cost

effective in application in remote location,

where the price to extend a power line to

the electricity grid is costly. They are used

in rural areas to provide water for livestock,

water pumps, farm lighting and fence.

Heat Storage & Water Hating System

A water heating systems are the alternate way to store energy. The conversion efficiency of a

resistance heater is nearly 100%. Heat loss can be minimized through insulation of storage

tank. Hot water can be used for domestic needs or for heating purposes in baseboard electric

home heaters.

The electricity in water heating systems is sent to resistance heaters sunk in water, which can

be DC or AC powered with unregulated voltage and frequency levels.

7

1. There are two types of solar water heating systems: - Active with circulating pumps and controls. They also subdivide on direct and indirect circulation system. In direct system, pumps circulate household water through the collectors into the home. In Indirect circulation systems, pumps circulate a non-freezing, heat-transfer fluid through the collectors and a heat exchanger, which heats the water that then flows into the home. This system is for using in climate with freezing temperatures, while direct work well in climate with rarely freezes due to water physical properties that can freeze in

pipes. - Passive water heating, In contrast with active, systems do not have pumps. They are less expensive, but not as efficient as active systems, while being more reliable with longer lifecycle. In areas where temperature rarely falls below freezing – integral collector-storage passive systems work best. In Thermosyphon systems water flows through the system when warm water rises as cooler water sinks. The collector installed below the storage tank so that warm water able to rise into the tank. This system requires installation of a heavy storage tank on the roof.

Storage tanks and solar collectors are often incorporated into water heating system. In two-tank systems, water is preheated by water heater in first tank, before enters the convential water heater. In one-tank systems, backup heater is combined with the solar heater. Three types are used for residential buildings:

8

Flat-plate collector

Two types of flat-plate collectors available:

- Unglazed, used for solar pool heating. They

have a dark absorber plate, made of metal or

polymer, without cover.

- Glazed, weatherproofed boxes with dark

absorber plate under one or more glass or

polymer plastic and consists of following layers:

- Glass protects absorber from the outside,

allowing 90% of sunlight to be absorbed.

- Insulation helps reduce heat loss.

- Absorber - a thin sheet of Aluminium is coated

with a highly selective material that is extremely

efficient at absorbing sunlight and converting it

into usable heat. The aluminium sheet is

ultrasonically welded to the copper riser pipes.

Riser & Header Pipe - the solar system heat

transfer fluid circulates through the header and

riser pipes, which are brazed together to form a

harp shaped heat exchanger. [13]

Evacuated-tube solar collectors

Parallel rows of transparent glass tubes feature

form evacuated-tube solar collectors. Each tube

contains a glass outer tube and metal absorber

tube attached to a fin. The Fin’s coating absorbs

solar energy but inhibits radiative loss.

Cross Section of a Single Evacuated or Vacuum Tube & view on the roof

Flat –plate collector. View on the roof (top) &

Schematic section of (bottom)

9

Integral collector-storage system

In ICS or batch systems one or more black tanks or tubes in an insulated, glazed box combined. First cold water passes through the solar collector, which preheats the water. Then water enters conventional backup water heater, providing adequate temperature.

Solar Power Tower

Scheme of working process of Solar Power Tower. See also Appendix 3, page 22.

Solar Thermal Tower is another way of converting thermal solar energy into the electricity. This

system works same as traditional power plants by creating high temperature steam to turn

turbine. Generator produces electricity enough for industrial use.

System consists of:

- Solar Receiver or Boiler – on the top of tower. It receives concentrated sunlight; as a result

water converts to high-temperature steam.

- Heliostats – mirrors, controlled by software for concentrating sunlight on a central tower.

- Turbine – when hot air accumulates in the tower, it acts like an exhaust pipe provoking

movement turbines and producing electricity in outcome.

Integral collector storage tank

10

- Air-cooled condenser – steam powers

a turbine and is then converted back to

water through air-cooled condenser.

Storage – extends solar electricity

production for night time.

Solar Reflectors

The three most common types of solar

reflectors are parabolic troughs and

dishes. Both use mirrors shaped like

parabolas to focus incoming radiant

energy onto a fluid-filled pipe that runs

down the center of a trough. [14]

Location

Solar towers are rentable in locations

only with a high amount of sunshine.

Areas selected that are near roads and

existing transmission lines – places

where human activity has already left

its mark, such as grazing lands; where

there is a reduced need for new

transmission lines, and where

environmental impacts can be

minimized.[15]

11

Solar Wall PV/Thermal Hybrid System

Solar Wall PV/T and Solar Duct PV/T are hybrid systems that provide pure electricity and heat

captures from the sun. Renewable energy generation usually utilizing sun radiation in two ways

– Electricity, using photovoltaic

cells PV;

- Thermal generation heating water

or air.

As Sun produces both kinds of

energy at the same time, it creates

issues for PV panels, as they lose

efficiency under heating conditions.

At the same time, heat not always

required for the building or may not

achieve required temperature in

cold season, while conversion sun

rays into the electricity can be 3 to

4 times less efficient than thermal

conversion. However, combined

system of capturing both heat and electricity, optimize the useful energy generated from the sun

and improve energy output in the range of 200-300%, depending on air flow and other design

considerations.

Typical PV modules have efficiency of converting solar energy up to 15%. The rest of heat

energy is not only lost, but decreases PV arrays performance. If outdoor temperature is above

25 oC, with every addition 1 oC the output of PV drops by 0.5%. That means electrical output of

a typical rooftop array that may measure at 55 to 75 oC would fall by 12 to 25 % below the name

plate rating, producing only 7.5 to 8.8 kW instead 10 kW.

A hybrid system not only capturing heat and utilizing it as an additional energy output, but

benefit array system, by recirculating fresh air around each PV module, increasing its efficiency

by 5-10%.

The results of the performance

of this hybrid technology

showed that the adding the

SolarWall thermal component

to a PV array enhances the

total efficiency to over 50%

compared with 10-15%

efficiency for conventional PV

modules.

The “double-duty” of thermal

panels and PV racking system

contribute also to a cost

effectiveness of hybrid system.

12

Two types of SolarDuct and SolarWall offered in configuration with PV modules.

SolarDuct is available in a modular roof-top

configuration. The PV modules are

mounted on top of the SolarDuct unit, so

heat is drawn off the back of the PV

modules and conveyed through a duct to

the rooftop air handling unit, from where

this preheated air is then channeled into the

building HVAC system. The modular units

are easy in installation and angled at an

optimum orientation for maximum solar

gain.

In second configuration, PV modules are

assembled on the top of the SolarWall. The

warm air is also ducted into the building

conventional HVAC system. Dampers direct the

unwanted heat away from the building in

warmer weather, still providing recirculation of

fresh air around PV modules.

The following additional

features benefits system

and accelerate the PV

system return on

investments:

- This system has higher

life cycle cost savings,

because of the heat

energy from SolarWall

componentt;

- SolarWall panels replace

the conventional racking

system needed to mount

PV;

- Huge reduction in

greenhouse gas

emissions, as this system

displays using natural gas

or heating oil

- Decrease both heating

and electricyti costs. [7, 8]

PV – with SolarDuct (on top & left corner) and SolarWall (bottom)

See also Appendix 1, P. 20 - Implementation of hybrid Solar Wall & Duct PV/T systems

within building structure

13

Solar Energy Conversion Process: Light and Heat

Solar panels and solar-powered devices typically use heat or light for converting it into the

energy. However, they have never been able to use both simultaneously. The heat producing by

sun even decreasing solar cells efficiency, as it was reviewed in previous chapter. Photon The

new process of Enhanced Thermionic Emission (PETE) combines the heat and light solar

radiation to create electricity.

Scientists from Stanford state that this technology is breakthrough in a new energy conversion

process, especially as the materials required to produce PETE are very affordable.

They discovered that by shelling a piece of semiconducting material with a layer of metal

cesium, enabling the converting heat and light radiation into the electricity at the same moment.

The efficiency of PETE process is increasing, as the panel temperature arises. However, it does

not reach maximum efficiency until the panel’s temperature reach of 200 oC, while traditional

solar panels reach heat around 100 oC on a hot day in the sun. It causes the application of this

technology more efficient in concentrators (i.e. parabolic dishes), which are used to power entire

grids and communities. Researches state that the efficiency in large concentrators using PETE

can be increased by 55%. [9]

Nanotechnology

Other studies

regarding the

increasing efficiency

of the solar cells were

announced by

Princeton University.

Scientist applied a

“nano-mesh” to

plastics that make a

way for producing

inexpensive

flexible devices

and greatly increasing

the efficiency of

…………………………………………………………………………………….standard PVs.

This new nanotechnology demonstrates the ability to triple the efficiency of solar cells by

excluding two principal factors of light loss and reflection.

Nano-mesh is designed to dampen reflection and trap light to be converted into electrical

energy.

It absorbs 96% and reflects only 4% of the light, increasing the efficiency of converted light into

energy in 52% higher than conventional PV in direct sunlight and up to 175% on cloudy days.

[10]

14

Solar Thermal Cooling

Solar chillers use thermal energy provided by the sun or other backup sources to produce cold

and/or dehumidification.

There are two main solar cooling processes:

- Closed cycles, where thermally driven sorption chillers produce chilled water for use in space

conditioning equipment

- Open cycles, also referred to as desiccant evaporative cooling systems (DEC), which typically

use water as the refrigerant and a desiccant as the sorbent for direct treatment of air in a

ventilation system.

Solar cooling has a number of advantages over alternative solutions:

- It can help reduce the electricity peak demand associated with conventional cooling, as

maximum solar radiation usually occurs when cooling is needed. Solar thermal cooling can also

operate in the evening by using thermal storage.

- When summer is over, solar cooling systems can be used for heating purposes such as

domestic hot water preparation or space heating. [17]

Silicon was used for the solar cells because of its efficiency at converting sunlight at energy.

However, it is expensive and brittle, so protective materials like heavy glass or some other

polymer plastics have cover it. It makes manufacture process costly, as well as transportation,

storage and installation. Bulky, rigid and heavy constructions of convention PV is hard to

integrate within the building architectural design. They are used only as pure systems for

generating energy.

It is not surprising that the engineers’ research new technologies to solve those problems and

find light, flexible, and easy produced at low cost product that besides power output, can be

easily integrated within the building structure. The following chapter is dedicated to explore

opportunities of that technologies as well as challenges and potential of large-scale production

in near future.

Hybrid Solar Air Conditioning Diagram. Machine-History.com

15

Transparent Polymer Solar Cell

The new generation of the transparent solar cells has been recently invented by UCLA

(University of California, Los Angeles) researches.

This new material is nearly 70%

transparent to the human eye, so could be

used as glazing material for windows or

curtain wall systems that produce energy.

A photoactive plastic absorbs not visible

infrared light and converts it into an

electrical current.

Accomplished by lightweight, flexibility and

potential of being produced in high volume

at low cost, this technology is attractive for

the smart windows and building-integrated

photovoltaics applications, as recharging

surfaces for portable electronics (laptops,

cellphones and MP3 players).

These results were achieved by incorporation of near-infrared light-sensitive polymer and silver

nanowire composite films as the top transparent electrode. A mixture of the silver nanowire and

titanium dioxide nanoparticles allows inventing the transparent conductor that replaced the

opaque metal electrode used in the past.

Implementation this new technology is very exciting for producing the transparent conducting

windows as a new ecological building product in a sustainable architecture. [2]

Organic Solar Cells or Photovoltaic Cells (OPVs)

The third-generation of the photovoltaic (third-gen PV) or organic solar cells (OPV) was

introduced for the market by Massachusetts-based manufacturer Konarka Inc.

Carbon-compound based organic

materials are used in form of small

molecules, dendrimers and

polymers, to convert solar energy

into electric energy. Having the

ability to absorb light these semi

conductive organic molecules induce

and transport electrical charges

between the conduction band of the

absorber to the conduction band of

the acceptor molecule.

Single and Multilayer types of OPVs

are currently used in research.

The Structure of a Single-Layer & a Multilayer Organic Solar Cell See also Appendix 2, P. 21- Schematic Comparison of Rigid Crystalline Silicon to a Flexible Organic Solar Cell

16

Manufacturing Process & Cost.

Due to molecular nature of the used material, organic cells could be manufactured much easier

than silicon based. Molecules can be easy inked or printed on the thin film substrates that are

1,000 times thinner than silicon cells,

which reduce the production cost

significantly. It makes the storage,

installation and transportation very

undemanding, as they offered in

convenient (eg. rolled) portable forms-

less prone to damage and failure, much

lighter and flexible comparing to the

conventional silicon panels.

Due to mechanical flexibility, solar cells

can be spread over irregular shapes, as

pneumatic cushions structures, tents or

curtain wall façade systems.

Moreover, low-temperature and low-

energy demands of organic cells

production process also reduce cost factor.

Principle of work.

Solar cells can be likened roughly to penlight batteries. In an AA cell, a chemical reaction drives

electrons from the positive (+) to the negative (-) pole, while in solar cells, the energy of light

moves electrons. When a photon of light strikes a solar cell, it generates a pair of positive and

negative charge carriers. When the pair separates inside the cell, they make current. [6]

Application.

Organic Solar Cells able to perform

power without cooling, which means

they can be integrated into a

“sandwich” building elements, even

if they do not provide back-

ventilation for integrated PV panels.

The power output of third-gen PV

technologies is not so dependent on

the access of direct solar radiation,

compared with silicon, suggesting

high performance under low light

conditions such as fog, partially

shaded building surface areas or

indoors.

17

This makes third-gen PV an ideal candidate for cloudy or

smoggy environments such as major built up cities, where low

light conditions are commonplace; in equatorial areas, where

lots of clouding is caused by the Intertropical Convergence Zone

(ITCZ); or in high latitudes, where overcast skies are typical. In

addition, third-gen PVs can be developed for certain types of

indoor applications, like powering emergency lights or motion

detectors. [4]

Besides advantage of the transparency, at night this structures

can be illuminated by LED lights or multimedia screens, printed

in variety spectrum of colors and patterned through all the

façade. This blend of sustainable and digital technologies

significantly impacts on contemporary architecture changing the

way how the buildings would be designed and produced and

open up the market for building-integrated PV products (BIPV).

Well-known examples of that structures integrated within the

facades are the Olympic Swim Stadium in Beijing, China, Burj Al

Arab in Dubai, Allianz Arena in Munich.

Challenges.

Besides numerous advantages, third-gen PVs

have lower efficiency (5%) comparing to the

conventional solar panels, and short lifetime.

They more complement silicon panels, then

able to compete with them.

Nonetheless, inexpensive production and

undemanding maintenance encourage further

research in developing new polymeric materials

and combinations to enhance efficiency, exceed

the lifetime pending 20-30 years and achieve

large-scale production at low-cost within the

next decade.

Glass is the most popular and durable building

material nowadays, with relatively small impact

on the environment. The technologies of a new

coating and material combination, accomplished

with engineered advances rapidly developing, in

order to generate a first-class benign product

………………………………………………………for nowadays and prospect. [3,4,6]

18

Conclusion

The oil based fuels are dwindling and technologies based on those utilizations eventually

proceed to a crisis. Solar energy technologies have a great potential and there is a huge

demand for this kind of technologies. The applications are widespread and allow harnessing all

kinds of solar radiation – from light to heat and infrared light, producing electricity, hot water and

even cooling to provide air conditioning for the houses. The scale of devices also striking by its

diversity: from solar cooking appliances for residential houses, to solar thermal towers that

produce energy enough for industrial purposes. Variety of applications in architectural field allow

to manage and minimize energy consumption, providing owners and occupants clean energy

that lead to a great savings in future.

The great minds are forced in developing solar technologies and we can expect more

improvements in covering most of our energy requirements by a solar energy in near future.

19

References:

[1] Mechanical and Electrical Systems in Architecture, Engineering and Construction, 5/e

Frank R. Dagostino and Joseph B. Wujek

[2] Science & Technology News Since 1998. Highly Transparent Polymer Solar Cell Produces

Energy by Absorbing Near-Infrared Light. (http://scitechdaily.com/highly-transparent-polymer-

solar-cell-produces-energy-by-absorbing-near-infrared-light/)

[3] Bright Hub. Organic Solar Cells vs Semiconductor-based Solar Cells.

(http://www.brighthub.com/environment/renewable-energy/articles/95572.aspx#imgn_2)

[4] Plastic Electronics. Building design and the potential of third-generation solar cells ()

[6] National Research Council Canada. ARCHIVED - Shaped to fit: flexible solar cells

(http://www.nrc-cnrc.gc.ca/eng/dimensions/issue4/solar_cell.html)

[7] Solar wall. PV/Thermal; Hybrid Solar Heating + Electricity

(http://solarwall.com/en/products/pvthermal.php)

[8] Kipp & Zonen. Sun Shines on JMSB building. (http://www.kippzonen.com/News/75/Sun-Shines-

on-JMSB-building#.VIx3641B_IU)

[9] The Alternative Energy eMagazine. Solar Energy Conversion Process: Light and Heat

(http://www.altenergymag.com/emagazine/2010/08/solar-energy-conversion-process-light-and-

heat/1564)

[10] Great Things from Small Things. Nanotechnology Innovation. Nanotechnology triples solar efficiency. (https://genesisnanotech.wordpress.com/2012/12/12/nanotechnology-triples-solar-efficiency/)

[11] Solar Direct. Photovoltaic Systems. (http://www.solardirect.com/pv/systems/systems.htm)

[12] Energy.Gov. Solar Water Heaters. ( http://energy.gov/energysaver/articles/solar-water-heaters )

[13] Apricus. Flat-Plate Solar collectors. (http://www.apricus.com/flat-plate-solar-collectors-3/)

[14] Bright Source. Technology. (http://www.brightsourceenergy.com/technology)

[15] Energy Home. Solar Reflectors.

(http://www.energyeducation.tx.gov/renewables/section_3/topics/solar_reflectors/index.html)

[16] Smarter Building Technology(http://www.metalarchitecture.com/articles/magazine-

features/smarter-building-technology.aspx)

[17] European Solar Thermal Industry Federation. Cooling with solar thermal.

(http://www.estif.org/st_energy/technology/solar_thermal_cooling_and_air_conditioning/)

20

Appendix

1. Implementation of hybrid Solar Wall & Duct PV/T systems within building structure.

21

2. Schematic Comparison of Rigid Crystalline Silicon to a Flexible Organic Solar Cell

22

BrightSource has approximately 1.8 gigawatts of power under contracts with Southern California

Edison and Pacific Gas & Electric Company, California’s two largest utilities. In addition, the

company manages an approximately 90,000 acre development site portfolio in California and

the U.S. Southwest that has the potential to accommodate approximately 9 GW of installed

capacity. [14]

3. Scheme of working process of Solar Power Tower

23

Solar pool cover not only prevents heat from escaping, but absorbing thermal energy that is used for heating the pool.

4. Implementation of solar technologies in different fields

LED Street Lights by Petra Smart Solution. (http://www.greentechmedia.com/multimedia)

Solar cooking device

Solar shaded parking

24

Another variation of

Building Integrated

PV installations are

Solar Panel Awnings

and Solar Roof

Shingles.

5. Solar Panel Awnings and Roof Shingles