solar powered glass window

8/2/2019 Solar Powered Glass Window

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RENEWABLE ENERGY RESOURCES

PROJECT

SOLAR POWERED GLASS WINDOWS

MADE BY:

ABHISHEK JAIN(10BME1004)

BHURE NIKHIL(10BME1030)

DEBADATTA TRIPATHY(10BME1032)

N. SRINATH(10BME1063)

NIKHIL GUPTA(10BME1065)

RISHABH MONGA(10BME1081)


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CONTENTS

1.DEFINITION..22.DESIGN4 3.WORKING..84.CALCULATIONS..115.

INSTALLATION OF BUILDING INTEGRATED13PHOTOVOLTAIC SYSTEMS

6. USES..14 7. DISADVANTAGES..17 8. REFERENCES.19


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1.DEFINATION:Solar technology is a rapidly expanding market requiring repeatability, tight

specifications, innovation and cost effectiveness to help propelmankind into a

sustainable energy future. The solar industry, The Glass Window uses the

sunlight, and heat from the sun, to generate electricity,reducing heat, andproviding a semi-transparent window that provides privacy, while maintaininga

comfortable level of visibility to the outside world. At the same time Glass

Windows provide a 100% reduction in Ultraviolet and Infrared radiation, adding

that extra level of protection not offered by standard glass windows. Shining on

the solar cells induces the photovoltaic effect, generating unregulated DC electric

Power. This DC power can be used, stored in a battery system, or fed into an

inverter that transforms and synchronizes the power into AC electricity. The

electricity can be used in the building, home or exported to a utility company

through a grid interconnection.


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2.DESIGNPhotovoltaic (PV) Technologies

There are two basic commercial PV module technologies available on the market

today:I. Thick crystal productsinclude solar cells made from crystalline silicon either as

single or poly-crystalline wafers and deliver about 10-12 watts per ft of PV array

(under full sun).

II. Thin-film productstypically incorporate very thin layers of photovoltaic activematerial placed on a glass superstrate or a metal substrate using vacuum-

deposition manufacturing techniques similar to those employed in the coating of

architectural glass. Presently, commercial thin-film materials deliver about 4-5

watts per ft of PV array area (under full sun). Thin-film technologies hold out the

promise of lower costs due to much lower requirements for active materials and

energy in their production when compared to thick-crystal products.

A photovoltaic system is constructed by assembling a number of individual

collectors called modules electrically and mechanically into an array.

Building Integrated Photovoltaic (BIPV) System


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Building Integrated Photovoltaic (BIPV) is the integration of photovoltaic (PV) into

the building envelope. The PV modules serve the dual function of building skin

replacing conventional building envelope materialsand power generator. By

avoiding the cost of conventional materials, the incremental cost of photovoltaic

is reduced and its life-cycle cost is improved. That is, BIPV systems often havelower overall costs than PV systems requiring separate, dedicated, mounting

systems.

A complete BIPV system includes:

i. the PV modules (which might be thin-film or crystalline, transparent, semi-transparent, or opaque);

ii. a charge controller, to regulate the power into and out of the battery storagebank (in stand-alone systems);

iii. a power storage system, generally comprised of the utility grid in utility-interactive systems or, a number of batteries in stand-alone systems;iv. power conversion equipment including an inverter to convert the PV modules' DC

output to AC compatible with the utility grid;

v. backup power supplies such as diesel generators (optional-typically employed instand-alone systems); and

vi. appropriate support and mounting hardware, wiring, and safety disconnects.

BIPV system diagram

(Courtesy ofResearch Institute for Sustainable Energy (RISE)
http://www.rise.org.au/http://www.rise.org.au/http://www.rise.org.au/


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BIPV systems can either be interfaced with the available utility grid or they may

be designed as stand-alone, off-grid systems. The benefits of power production at

the point of use include savings to the utility in the losses associated with

transmission and distribution (known as 'grid support'), and savings to the

consumer through lower electric bills because of peak shaving (matching peakproduction with periods of peak demand). Moreover, buildings that produce

power using renewable energy sources reduce the demands on traditional utility

generators, often reducing the overall emissions of climate-change gasses.

A typical 50W module framed in black anodized

alumium is 1.26m long and 0.658m wide but only 30mm deep.

Design of a Building Integrated Photovoltaic (BIPV) System

BIPV systems should be approached to where energy conscious design techniques

have been employed, and equipment and systems have been carefully selected

and specified. They should be viewed in terms of life-cycle cost, and not justinitial, first-cost because the overall cost may be reduced by the avoided costs of

the building materials and labor they replace. Design considerations for BIPV

systems must include the building's use and electrical loads, its location and

orientation, the appropriate building and safety codes, and the relevant utility

issues and costs.

Steps in designing a BIPV system include:

I. Carefully consider the application of energy-conscious design practices and/orenergy-efficiency measures to reduce the energy requirements of the

building.This will enhance comfort and save money while also enabling a given

BIPV system to provide a greater percentage contribution to the load.

II. Choose Between a Utility-Interactive PV System and a Stand-alone PV System:a. The vast majority of BIPV systems will be tied to a utility grid, using the grid as

storage and backup. The systems should be sized to meet the goals of the


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ownertypically defined by budget or space constraints; and, the inverter must

be chosen with an understanding of the requirements of the utility.

b. For those 'stand-alone' systems powered by PV alone, the system, includingstorage, must be sized to meet the peak demand/lowest power production

projections of the building. To avoid over sizing the PV/battery system for unusualor occasional peak loads, a backup generator is often used. This kind of system is

sometimes referred to as a "PV-genset hybrid."

III. Shift the Peak:If the peak building loads do not match the peak power output ofthe PV array, it may be economically appropriate to incorporate batteries into

certain grid-tied systems to offset the most expensive power demand periods.

This system could also act as an uninterruptible power system (UPS).

IV. Provide Adequate Ventilation:PV conversion efficiencies are reduced by elevatedoperating temperatures. This is truer with crystalline silicon PV cells than

amorphous silicon thin-films. To improve conversion efficiency, allow appropriateventilation behind the modules to dissipate heat.

V. Evaluate Using Hybrid PV-Solar Thermal Systems:As an option to optimizesystem efficiency, a designer may choose to capture and utilize the solar thermal

resource developed through the heating of the modules. This can be attractive in

cold climates for the pre-heating of incoming ventilation make-up air.

VI. Consider Integrating Daylighting and Photovoltaic Collection:Using semi-transparent thin-film modules, or crystalline modules with custom-spaced cells

between two layers of glass, designers may use PV to create unique daylighting

features in faade, roofing, or skylight PV systems. The BIPV elements can alsohelp to reduce unwanted cooling load and glare associated with large expanses of

architectural glazing.

VII. Incorporate PV Modules into Shading Devices:PV arrays conceived as"eyebrows" or awnings over view glass areas of a building can provide

appropriate passive solar shading. When sunshades are considered as part of an

integrated design approach, chiller capacity can often be smaller and perimeter

cooling distribution reduced or even eliminated.

VIII. Design for the Local Climate and Environment:Designers should understand theimpacts of the climate and environment on the array output. Cold, clear days willincrease power production, while hot, overcast days will reduce array output;

a. Surfaces reflecting light onto the array (e.g., snow) will increase the array output;b. Arrays must be designed for potential snow- and wind-loading conditions;c. Properly angled arrays will shed snow loads relatively quickly; and,
http://www.wbdg.org/resources/daylighting.phphttp://www.wbdg.org/resources/daylighting.phphttp://www.wbdg.org/resources/daylighting.phphttp://www.wbdg.org/resources/daylighting.php


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d. Arrays in dry, dusty environments or environments with heavy industrial or traffic(auto, airline) pollution will require washing to limit efficiency losses.

IX. Reduce Building Envelope and Other On-site Loads:Minimize the loadsexperienced by the BIPV system. Employ daylighting, energy-efficient motors, and

other peak reduction strategies whenever possible.

3.WORKINGHOW A PHOTOVOLTAIC CELL WORKS :

i. A slab of pure silicon is used to make a PV cell. The top of the slab is verythinly diffused with an n dopant such as phosphorous. On the base of the

slab a small amount of a p dopant, typically boron, is diffused. The boron

side of the slab is 1,000 times thicker than the phosphorous side. The

phosphorous has one more electron in its outer shell than silicon, and the

boron has one less. These dopants help create the electric field thatmotivates the energetic electrons out of the cell created when light strikes

the PV cell. The phosphorous gives the silicon slab an excess of free

electron;it has a negative character. This is called the n-type silicon.The n-

type silicon is not charged, it has an equal number of protons and electrons

but some of the electrons are not held tightly to the atoms. They are free to


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move to different locations within the layer. The boron gives the base of

the silicon a positive character, because it has a tendency to attract

electrons. The base of the silicon is called p-type silicon. The p-type silicon

has an equal number of protons and electrons; it has a positive character

but not a positive charge.

ii. Where the n-type silicon and p-type silicon meet, free electrons from the n-layer flow into the p-layer for a split second, then form a barrier to prevent

more electrons from moving between the two sides. This point of contact

and barrier is called the p-n junction.When both sides of the silicon slab are

doped, there is a negative charge in the p-type section of the junction and a

positive charge in the n-type section of the junction due to movement of

the electrons and holes at the junction of the two types of materials. This

imbalance in electrical charge at the p-n junction produces an electric field

between the p-type and n-type silicon.


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iii. If the PV cell is placed in the sun, photons of light strike the electrons in thep-n junction and energize them, knocking them free of their atoms. These

electrons are attracted to the positive charge in the n-type silicon and

repelled by the negative charge in the p-type silicon. Most photon-electron

collisions actually occur in the silicon base.

iv. A conducting wire connects the p-type silicon to an electrical load, such as alight or battery, and then back to the n-type silicon, forming a complete

circuit. As the free electrons are pushed into the n-type silicon they repel

each other because they are of like charge. The wire provides a path for the

electrons to move away from each other. This flow of electrons is an

electric current that travels through the circuit from the n-type to the p-

type silicon.


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4.CALCULATIONS:

The following figure shows the irradiance, reflection losses, thermal

losses and available energy.

The efficiency of a collector can be described by:

=Qa/G

Where Qa is the available thermal power (W/m2), and G is the irradiance incident

on the glass pane (W/m2).

The available thermal power is calculated from the available irradiance at the

absorbe , converted into heat, minus the thermal losses through convection,

conduction and radiation:


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Qa=Ga-QL

Where QL represents the thermal losses (W/m2), and G is the available irradiance

(W/m2).

The available irradiance is given by,

GA=G

Where G is irradiance hitting the glass pane, is the degree of the glass, is the

degree of absorption of the absorber.

The thermal losses are dependent on the temperature difference between the

absorber and the air, .to the first approximation (for low absorber

temperature) this relationship is linear, and can be described by the heat losscoefficient , k (W/m2k):

QL=k

If the various values are substituted into the above equation, we obtain for the

collector efficiency:

= G-k

=k /G

At higher absorber temperature the thermal losses no longer increase linearly

with temperature difference but instead increase more strongly (by the power 2)

as a result of increasing thermal radiation. The characteristics line therefore has

some curvature and the equation in a second order approximately is:

=0- k1/G-k22/G

where k1 is the linear heat loss coefficient (W/m2k), and k2 is the quadratic heat

loss coefficient (W/m2k2).


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5.INSTALLATION OF BUILDING INTEGRATED PHOTOVOLTAICSYSTEMS:

Before installation the environmental and structural factors that should be taken

into consideration. Environmental factors include a structures solar access as well

as average seasonal outdoor temperatures at the site, local weather conditions,

shading and shadowing from nearby structures and trees, and the sites latitude,

which influences the optimum BIPV system orientation and tilt.

Structural factors include a buildings energy requirements, which influences the

size of the system, and the BIPV systems operation and maintenance

requirements. Some of the considerations are as follows:

1. SOLAR ACCESS:Solar access, the incidence of solar radiation (insolation)that reaches a PV surface at any given time, determines the potential

electrical output of a BIPV system.Statistical estimations of average dailyinsolation levels for specific locations are commonly used determine

whether the location is suitable for a BIPV and is measured as kilowatt-

hours per square meter per day (kWh/m2/day).

2. SYSTEM ORIENTATION AND TILT:To maximize solar access and power output, the physical orientation of the

BIPV system and the tilt angle of the array should be considered relative to the

geographical location of the building site.

i. As a general rule of thumb, BIPV installation to the north of the equatorperform optimally when oriented south and tilted at 15 degrees higher

than the site latitude. Conversely, BIPV installation to the south of the

equator is optimal when oriented north and tilted at an angle 15

degrees lower than the site latitude.

ii. Demonstrations have shown that a system installed at a tilt angleequivalent to the site latitude produces the greatest amount of

electricity on an annual basis.

iii. In comparison to a systems performance at latitude angle, annualperformance losses for vertical faade systems can be as high as 30% or

more. In contrast, annual performance losses for horizontal installations

can be as high as 10%, in comparison to those of systems installed at

latitude angle.


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3. SYSTEM SIZING:Architecturally, the size of the BIPV system is physicallylimited to the dimensions of the buildings available surface area. The

balance between the amount of power required and the amount of

surface area available can determine the type of PV installation

technique that will be used.

6.USESI. Historically, windows are designed with surfaces parallel to vertical

building walls. Such a design allows considerable solar light and heat

penetration due to the most commonly occurring incidence of sun angles.In passive solar building design, an extended eave is typically used to

control the amount of solar light and heat entering the window(s).

II. Photovoltaic windows not only provide a clear view and illuminate rooms,but also use sunlight to efficiently help generate electricity for the

building. In most cases, translucent photovoltaic cells are used.Skylights
http://en.wikipedia.org/wiki/Passive_solar_building_designhttp://en.wikipedia.org/wiki/Eavehttp://en.wikipedia.org/wiki/Eavehttp://en.wikipedia.org/wiki/Passive_solar_building_design


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admit harsh direct overhead sunlight and glare, either horizontally (a flat

roof) or pitched at the same angle as the roof slope. In some cases,

horizontal skylights are used with reflectors to increase the intensity of

solar radiation (and harsh glare), depending on the roof angle of incidence.

When the winter sun is low on the horizon, most solar radiation reflects offof roof angled glass (afternoon). When the summer sun is high, it is nearly

perpendicular to roof-angled glass, which maximizes solar gain at the

wrong time of year, and acts like a solar furnace. Skylights should be

covered and well-insulated to reduce natural convection (warm air rising)

heat loss on cold winter nights, and intense solar heat gain during hot

spring/summer/fall days.

III. A Building Integrated Photovoltaic (BIPV) system consists of integratingphotovoltaic modules into the building envelope, such as the roof or the

faade. By simultaneously serving as building envelope material and powergenerator, BIPV systems can provide savings in materials and electricity

costs, reduce use of fossil fuels and emission of ozone depleting gases, and

add architectural interest to the building.

IV. While the majority of BIPV systems are interfaced with the available utilitygrid, BIPV may also be used in stand-alone, off-grid systems. One of the

benefits of grid-tied BIPV systems is that, with a cooperative utility policy,

the storage system is essentially free. It is also 100% efficient and unlimited

in capacity. Both the building owner and the utility benefit with grid-tied

BIPV. The on-site production of solar electricity is typically greatest at or

near the time of a building's and the utility's peak loads. The solar

contribution reduces energy costs for the building owner while the

exported solar electricity helps support the utility grid during the time of its

greatest demand.


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7.DISADVANTAGESI. COST

i. High cost remains a major challenge with BIPV, requiring the existenceof state aids (subsidies and tax incentives) to reduce prices.

ii. BIPV systems are highly reliable in the long term (the averageguarantee in the long term being 20-25 years.

iii. They are almost maintenance free and, unlike any other buildingmaterials, the produce energy, therefore allow a building owner to

recover the initial cost of their investment with an average pay back

time of 10 years when state aids are in place.

iv. Annual return of investment is approx. 7% of the initial investment.v. The average residential installation has a capacity of 3kW so at

estimated average cost of 8/W, the overall cost for a customized

integration is in excess of24000.vi. For this reason, many states like France and Italy provide the highest

feed-in tariffs to BIPV systems which help those wanting to invest in

BIPV in getting the bank loans.

vii. The cost of customized BIPV system can go up to 40/W is not onlydictated by the cost of the solar PV module(and that of the inverter)


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which make up between 60% of the total system costs, but also up to

40 per by costs of installation, design, glazing, water-proofing, wiring.

viii. In general, however the major part of the cost of a BIPV system goes tothe module and inverters (at an average of 73 and 8%, respectively) and

the rest of the BOS (balance of system) cost. This implies that the

majority of the market share for BIPV goes to the module

manufactures, with a small share for the inverter manufacture and the

BOS suppliers.

SOLUTION TO HIGH COST

i. The main driver for the BIPV market in Europe has been the feed in thetariffs for solar PV generated power in countries like Germany, Spainand Italy and more recently France, Switzerland, and Portugal.

ii. Such feed in tariffs provide a large incentive for consumers andcompanies to adopt BIPV by allowing them to sell back excessive power

to the grid at a high price (3-5 times the grid price of electricity)

depending on the region and type of installation.

iii. In Europe, only the annual, growth rate during the 2007-2014 period isexpected to be 39.29% for installed capacity, with the market reaching

260.44MW of installations and a value of1185.9 million in 2014.

II. SPACE REQUIREMENTS


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The space requirements for the installation of solar glass windows including

the batteries is a major disadvantage because it occupies a lot of space.

III. MAINTENANCEi. The system requires a continuous assessment by the operator to check

for its efficiency.

ii. Since all the solar cells are connected in series, therefore themalfunctioning of even one cell causes a reduction in efficiency of the

whole panel.

iii. Accumulation of dust and other particles on the panel hinders with theworking of the solar panel.

8.REFERENCESi. www.gerindtec.com

ii. NATIONAL INSTITUTE OF BUILDING SCIENCESiii. www.interscience.wiley.comiv. http://www.solarserver.de/solarmagazin/index-e.htmlv. www.NEED.org
http://www.gerindtec.com/http://www.gerindtec.com/http://www.interscience.wiley.com/http://www.interscience.wiley.com/http://www.solarserver.de/solarmagazin/index-e.htmlhttp://www.solarserver.de/solarmagazin/index-e.htmlhttp://www.need.org/http://www.need.org/http://www.need.org/http://www.solarserver.de/solarmagazin/index-e.htmlhttp://www.interscience.wiley.com/http://www.gerindtec.com/

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