Gordon Howell, P.Eng.

©1995-2017Edmonton

6,000 kW solar PV array30,000 solar PV modulesGermany

11,000 kW solar PV array55,000 solar PV modules

Germany

5 kW solar PV array21 solar PV modulesLac Ste Anne

340 kW solar PV array1700 solar PV modules

California

Solar Photovoltaic ElectricitySolar Photovoltaic Electricity……clarifying some important termsclarifying some important terms

The correct use of terms is critical in effective communication The correct use of terms is critical in effective communication and supply contracts.and supply contracts.

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Solar heating Solar heating –– A A darkdark surface located in surface located in

the sunshinethe sunshine–– Water or air runs past the Water or air runs past the

solarsolar--heated surface heated surface carrying heat to the building.carrying heat to the building.

Solar heating and solar electricity

are NOT the same…

Solar electricitySolar electricity–– A semiconductor device like a computer chipA semiconductor device like a computer chip–– Employs the Employs the ““photovoltaicphotovoltaic”” effecteffect–– Photons bump electrons out of their orbitPhotons bump electrons out of their orbit–– Wires carry away the charge from the electronsWires carry away the charge from the electrons

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Solar Cells Absorb the Energy in

Photons

The technology is called "photovoltaics", but we only call it "PV".The energy in the photons knocks electrons out of their orbital shell – 1 electron for 1 photon.The electric field generated in the semi-conductor turns the charge from the electrons into an electric current. Wires carry the current away.

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PV Terms

Solar PV Solar PV ArrayArray

PV can generate any amount of electricity.PV can generate any amount of electricity.More electrical capacity More electrical capacity

requires more PV modules.requires more PV modules.

Solar PV Solar PV ModuleModuleSolar PV Solar PV CellCell

Solar ElectricitySolar ElectricityThe technology is called "The technology is called "photovoltaicsphotovoltaics", ",

but we only call it but we only call it ““PVPV”” for short.for short.

170,000 modules (200 W ea.) 170,000 modules (200 W ea.) 34,000 kW PV array34,000 kW PV array

30,000 modules, 6000 kW

5,000 modules1000 kW

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How PV terms relate to each other

As per the International Electrotechnical Commission’s standard IEC TS 61836 “Solar Photovoltaic Energy Systems – Terms, Definitions and Symbols”

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How PV terms relate to each other

solar PV cell(the only PV device

that generates electricity)

solar PV module(it is a product assembled at a

factory)

solar PV panel (it is an on-site assembly

of PV modules fastened together on one rack)

array – the complete on-site assembly of solar PV modules and racking

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The words…the differences…

Solar heating: Solar heating: –– thermal thermal collectorcollector (it produces heat)(it produces heat)

Solar electricity: Solar electricity: –– photovoltaic photovoltaic modulemodule (it generates electricity)(it generates electricity)–– as defined and agreed by the international solar PV as defined and agreed by the international solar PV

industry (and contained in the IEC TS 61836 industry (and contained in the IEC TS 61836 standard) and used around the worldstandard) and used around the world

–– as defined and used in the Canadian Electrical Codeas defined and used in the Canadian Electrical Code

Solar PV Solar PV panelpanel–– this is a term describing the PV array mounting this is a term describing the PV array mounting

configuration and is used in PV system design and configuration and is used in PV system design and array construction array construction onlyonly (otherwise who cares about it?)(otherwise who cares about it?)

–– it means it means ““several solar PV modules attached onto a several solar PV modules attached onto a mounting rackmounting rack””. It is usually an on. It is usually an on--site assembly.site assembly.

Solar PV Solar PV stringstring–– this is a term describing the PV array electrical this is a term describing the PV array electrical

configuration and is used in PV system design and configuration and is used in PV system design and electrical installation electrical installation onlyonly (otherwise who cares about it?)(otherwise who cares about it?)

–– it means it means ““several solar PV modules electrically several solar PV modules electrically connected in seriesconnected in series””. It is usually an on. It is usually an on--site assembly.site assembly.

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1 Solar PV Panel, 6 Solar PV Modules

This is a single solar PV panel.This panel consists of 6 solar PV modules mounted on two rails.

1995 May, Edmonton

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How many solar panels do you see here?

32 modules, arranged as 2 panels (in this installation)

2 collectors

1 collector

What words do we use?

Part of a Solarwall ventilation air pre-heating system

Part of a solar domestic water heating system

Part of a solar-electric generating system

Direct gain passive solar

space heating and illumination windows

(not panels)

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Solar PV SystemThe only thing that is functional and that you want is a solar PV systemsystem. You do not specifically want any of its individual components, because they don’t work unless they are part of a PV systemsystem.

Individual solar PV components will not provide you with the energy service you are wanting.

A solar PV systemsystem consists of:– solar PV modules, mounting rack, DC wiring, AC wiring, conduit, fittings,

disconnect switch, inverter, meter

– development, planning, modelling, design, procurement, supply, installation, inspection, commissioning, operation

A solar PV systemsystem provides:– clean reliable local energy, utility bill savings, emission reductions

– fascination, hope, anticipation, enjoyment

– leadership, prosperity, energy democracy, energy resilience

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Many other specialised PV system terms

PV cell string

PV sub-string

PV sub-array

PV assembly

PV generator

PV generating station

PV energy system

PV power system

PV plant

PV field

PV farm

PV installation

As per the International Electrotechnical

Commission’s standard IEC TS 61836 “Solar Photovoltaic Energy Systems –

Terms, Definitions and Symbols”

www.iec.ch

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How a PV SystemFunctions

in a Building

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Solar Photovoltaic ElectricitySolar Photovoltaic ElectricitySimple Simple –– Clean Clean –– Reliable Reliable –– AffordableAffordable

Local Local …… Equitable ... Democratic Equitable ... Democratic …… NowNow

Gordon Howell, P.Eng.Howell-Mayhew Engineering

EdmontonPhone: +1 780 484 0476

E-mail: ghowell@hme.ca©1995-2017Photo credits: Gordon Howell and several others

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