Pv 02 Cells Components

8/12/2019 Pv 02 Cells Components

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AGENDA

INTRODUCTION

CELLS AND COMPONENTS

PV PERFORMANCE

PV APPLICATIONS

CODES AND STANDARDSEMERGENCY RESPONSE


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Give me the splendid silent sun with all its beams full - dazzling. Walt Whitman, 1865

OBJECTIVE

To recall the principles of photovoltaics

To identify the components of a

photovoltaic system


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SOLAR FACTS

One day of sunshine could supply allthe worlds energy for 4 to 5 years

The Suns full intensity andbrightness is 1,000 watts per metersquared (referred to as insolation)

This intensity can be diminishedaccording to the micro climate andsite specific conditions (shade)

PV CELLS & COMPONENTS


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SOLAR FACTS In the Northern Hemisphere, mostphotovoltaic systems are orientated towardstrue south to maximize the amount of light

falling on the photovoltaic panels

Peak sun per day is about 5 hours, between10 am and 3 pm (peak energy production)



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Anatomy of a Solar Cell The solar cell is the smallest unit of the PV system

There are two types of manufactured PVs:

Silicon cell or Amorphous silicon

PV cell has a thin layer of silicon 1/100th of an inch

Silicon is layered with other materials to create thephotoelectric reaction



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Anatomy of a Solar Cell

Boron is used for the positive layer

Phosphorus is used for the negative layer

Photons generated from the sun energize andknock loose the extra phosphorus electronwhich crosses the P/N junction to fill the hole

on the boron atom

The energy released in the process produces.5 volt of direct current (DC)



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The Photovoltaic Effect


Phosphorus -Boron +


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MANUFACTURING PROCESSES

The purest silicon structure comes from thegrowth of a single crystal, monocrystalline ,cut in to thin wafers

Multiple crystals cast together and sliced intothin wafers form polycrystalline structures

A chemical process that deposits silicon on asubstrate material like glass or stainless steel as athin film is referred to as amorphous



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MANUFACTURING PROCESSES

To improve PV efficiency and reduce cost, theindustry is using materials such as cadmiumtelluride and gallium arsenide

Toxic and hazardous chemicals are usedin the PV manufacturing process

When a module is exposed to fire or anexplosion, trace chemicals can be releasedinto the atmosphere



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MonocrystallineModules have output capacities of 14 to 15%

Monocrystalline achieves the highest efficiency inelectric energy production

Its production cost is higher than other silicon types



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PolycrystallinePure molten silicon is cast into molds, thensliced into wafers, doped and assembled


Installation of polycrystalline

modules on a rack system.

Polycrystalline is lower inconversion efficiencycompared to Monocrystalline,averaging about 12 to 14%

output capacity


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AmorphousMade by vaporizing silicon and depositing iton a glass, steel or flexible surface

Some are flexible and are able to be rolledand used for remote electricity generation

The flexibility of amorphous technology allows

it to be used in a wider range of applications



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A semitransparentamorphous siliconproduct used as a gasstation canopy inFairfield, California

Top - looking down

on the canopyBottom looking upthrough the canopy


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Amorphous

Production costs less than otherproduction techniques, but the outputcapacity, is reduced to 5 to 7%

A square foot of amorphous siliconaverages about 5 watts, monocrystallineor polycrystalline average about 10 watts

per square foot



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The Photovoltaic System Includes

Modules/Array (Tiles or Shingles)

Optional Batteries

Battery Controller

Inverter

Mounting Systems



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Photovoltaic Modules

PV cells connected in series and parallel the voltage and amperage is accumulated toachieve the desired electrical output

Photovoltaic cells connectedtogether form a PV module

Weather-proof electrical connectionsconnect modules together

In rare occasions junction boxes can overheatand can lead to roof damage and potential fire



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Photovoltaic Modules

Modules have a variety of sizes and ratedoutput, with the standard size module at 24-volts, consisting of 72 solar cells

An average size crystalline module weighsbetween 30 and 35 pounds

Photovoltaic panels have no moving parts andrequire little maintenance



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Photovoltaic Array

Two or more modules connectedtogether form a photovoltaic array

Residential system outputs of600 volts are not uncommon

The average household in California uses

about 6,500 kilowatt-hours per year



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Photovoltaic ArrayThe modules wired together in series to accumulatevoltage, and the strings are wired together in parallel toIncrease amperage, collectively they form the array

Array in Series and Parallel



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Photovoltaic Array

A PV system in the 3 to 4 kilowatt range wouldmeet most homeowners electricity needs

A 30 module array would operate at over4,000 watts and weigh approximately 900to 1,050 pounds

This weight spread equally over a 420 squarefoot area of the roof would result in a roofweight load of 2.5 pounds per square foot



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Photovoltaic Tiles and Shingles

PV tiles or shingles can be integratedinto the homes roof covering

It takes more time, wiring individualtiles or shingles together

PV tile or shingle roofing systemis less obtrusive but costs more

In High Fire Hazard Severity Zones, roofingsystems must meet Class A of Title 24 CCR



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Photovoltaic Tiles and Shingles


Manufacturers of PV shingles haveachieved a Class A rating by usinga fire resistant underlaymentbeneath the PV shingles

Somemanufacturers ofPV roofing tiles

have tested theirproducts and meetthe standard forClass A roofing


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Batteries

Lead acid batteries are usedto store PV-generated electricity

Batteries are used in off-grid PV systems,although battery back-up can be used ingrid-connected applications

Without batteries, a grid-tied PV systemcannot provide PV electricity when the utilitygrid is not energized



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Batteries


Pinnacles National Monument in California installed a 9.6-kilowatt photovoltaic system. It eliminates the fuel bill for a

diesel generator that produced 143 tons of carbon.


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Batteries

A battery is an electrochemical cell

The electrical potential between thepositive and negative electrodes is about 2volts direct current (DC)

The battery can off-gas oxygen from the

positive electrode and hydrogen from thenegative electrode

Escaping gases are highly flammable, sparksand open flames are not allowed near the batteries



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Batteries


Like the PV modules,

batteries are wired inseries and parallel toprovide the voltage andamperage necessary forthe operation of the

electrical system


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Battery Charge Controllers

To keep battery charge levels in check, acharge controller is used in the PV system

The battery charge controller prevents overcharging reducing the danger of off-gassing

Many controllers also protect the battery from

over-discharges as well



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Battery Charge Controllers


Battery charge controllers are found in off-grid systems

and grid-tied systems that have a battery back-up.


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PV Inverters

The PV array, batteries and charge controllersall function on direct current (dc)

Most household appliances run on alternatingcurrent (ac)

The inverter changes the direct current to

alternating current at 60 hz



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PV Inverter


This sine wave inverter isused on a grid-tied system.

A look inside an inverter during the installation process.


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PV Inverters

There are three types of inverters; squarewave, modified square wave and sine wave

Sine wave inverters produce a high qualitywaveform used to operate sensitive electricalequipment

Sine wave inverters are required for grid-tiedPV systems

Grid-tied inverters are designed to shut downwhen there is no grid power



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Mounting Systems


PV modules can bemounted directly on theroof, in many casesspecialized roof racks liftthe array from the roofdeck allowing air tocirculate under themodules.

Many PV systems aredesigned to withstand 80mile per hour winds.


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Mounting Systems


PV systems can also bemounted on the ground usingcustomized racks, or they canbe mounted on poles.


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Other Solar Technologies


The long rectangular panel at the bottom ofthis array is a solar water heating panel.

Solar thermal panels (solar water heating collectors) areused to heat water for the swimming pool or for domestichot water

Two solar hot waterpanels are on theleft of this roof and44 modules of this 7

kw PV array on theright of this 3,000sq. ft. home. Thesystem is backed-upwith a generator.


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Other Solar Technologies

Skylights are a function of passive solardesign, allowing natural light to enter theinterior of the building


A skylight with integratedphotovoltaic will have adistinctive amorphousrectangular pattern in the

glass


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PV panels areDistinctive: making

them relativelyeasy to recognizewhen you know what

to look for!

PhotovoltaicIdentification


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SUMMARY

The greatest danger for emergency respondersis the lack of PV knowledge needed to safely

operate around this emerging technology

This section provided you with anintroduction to the photovoltaic system

Identification of the PV array and all the relatedcomponents is critical in an emergency response

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Pv 02 Cells Components