Residential Implementation of Photovoltaic Residential Implementation of Photovoltaic SystemsSystems

By By Chris Hinton & Patrick PattersonChris Hinton & Patrick Patterson

Off-Grid & Grid Off-Grid & Grid TiedTied

Mounting Mounting TechniquesTechniques

InvertersInverters

System Sizing System Sizing & Design& Design

PV ModulesPV Modules

Future of PVsFuture of PVs

Placement Placement & & OrientationOrientation

Energy Energy StorageStorage

Charge Charge controllerscontrollers

Two Types of Residential Two Types of Residential Photovoltaic (PV) SystemsPhotovoltaic (PV) Systems

• Off-gridOff-grid • Grid-tiedGrid-tied

Golden, Colorado- National Renewable Energy Lab

East Lansing, Michigan- National Renewable Energy Lab

Off-grid PV Systems Off-grid PV Systems

Power for remote Power for remote systemssystems

Cost-prohibitive Cost-prohibitive utility line utility line extensionsextensions

“…“…Electric company quoted US$7 a foot to bring in the utility line Electric company quoted US$7 a foot to bring in the utility line from about a mile away (about US$37,000).” from about a mile away (about US$37,000).”

- - Home Power Magazine #92 Pg 22Home Power Magazine #92 Pg 22

Location unknown- SolarDepot.com

Grid-tied PV SystemsGrid-tied PV Systems

Net MeteringNet Metering

Local incentives Local incentives promote grid-tied promote grid-tied systems exclusivelysystems exclusively

Reduce peak power Reduce peak power demand on utilitydemand on utility

- Energy Trust of Oregon

PV System SizingPV System Sizing

• Energy use & auditingEnergy use & auditing

• Energy efficiency measuresEnergy efficiency measures

• Energy requirements for PVEnergy requirements for PV

How much power do you How much power do you need?need?

Off-grid System Off-grid System ConsiderationsConsiderations

Begin with precise load Begin with precise load calculationscalculations

Reduce load requirements Reduce load requirements through efficiency through efficiency measuresmeasures

Estimate energy Estimate energy production potential from production potential from solar insolation datasolar insolation data

Select PV hardware to Select PV hardware to match load requirementsmatch load requirements

Design system to match Design system to match loadload

- Xantrex

Grid-tied System Grid-tied System ConsiderationsConsiderations

Examine previous power billsExamine previous power bills

Implement energy efficiency Implement energy efficiency firstfirst

Estimate production potential Estimate production potential from solar insolation datafrom solar insolation data

Choose % of load to matchChoose % of load to match

Select PV hardware for utility Select PV hardware for utility interconnectioninterconnection

Design system Design system economicallyeconomically

- Xantrex

Module Placement & Module Placement & OrientationOrientation

Implications of Implications of shadingshading

The sun pathThe sun path

AzimuthAzimuth

Tilt angleTilt angleMoorepark, California- BP Solar

Tracing the SunTracing the Sun

Seasonal sun path Seasonal sun path variationsvariations

Solar pathfinder toolSolar pathfinder tool

Obstacles to sunlight Obstacles to sunlight can be traced and can be traced and predicted for predicted for different times of the different times of the yearyear

- Home Power Magazine # 57, pg. 32

- Real Goods

Module Placement & Module Placement & Orientation GuidelinesOrientation Guidelines

Standard PV module azimuth rule:Standard PV module azimuth rule:(Orientation) = (True South)(Orientation) = (True South)

Note: In Portland, true South is Note: In Portland, true South is aboutabout

19° east of magnetic South19° east of magnetic South

Standard PV module tilt rule: Standard PV module tilt rule: (Angle from horizontal) =(Angle from horizontal) =

(Geographic Latitude) (Geographic Latitude)

- Real Goods

http://www.proaxis.com/~johnbell/iitt/questionftf49.htm

What About Azimuth & What About Azimuth & Performance?Performance?

-Home Power Magazine # 93, pgs. 24-28

Effects of Tilting PV Effects of Tilting PV ModulesModules

Maximize energy production by optimizing tilt angle

Seasonal adjustments can further maximize production capabilities

- Home Power Magazine # 57, pg. 35

How much does tilt angle really How much does tilt angle really matter?matter?

-Home Power Magazine # 93, pgs. 24-28

Module Placement & Module Placement & Orientation Orientation ConsiderationsConsiderations

Placement and orientation often Placement and orientation often depend upon system priority: depend upon system priority:

Off-grid systems should maximize Off-grid systems should maximize energy production energy production

Grid-tied systems often maximize Grid-tied systems often maximize aesthetics characteristicsaesthetics characteristics

Aesthetics CountAesthetics Count

This is the same house!

-Home Power Magazine # 93, pg. 26 -Home Power Magazine # 93, pgs. 10, 11

Module MountingModule Mounting

Roof Mounted

Ground Mounted

Trackers

- National Renewable Energy Lab

-Home Power Magazine # 93, pg. 15

-Home Power Magazine # 95, pg. 127

Mounting ConsiderationsMounting Considerations

PV coolingPV cooling Wind resistanceWind resistance Structural StabilityStructural Stability Code complianceCode compliance PV OrientationPV Orientation AestheticsAesthetics Visibility (visible installations may Visibility (visible installations may

increase public awareness of renewable increase public awareness of renewable energy)energy)

Oak Park, California- BP Solar

Energy StorageEnergy Storage

Off-grid storage needsOff-grid storage needs Grid-tied energy storageGrid-tied energy storage Cost and Efficiency ConsiderationsCost and Efficiency Considerations

- National Renewable Energy Lab

- Home Power Magazine # 27, pg. 34

Off-grid Energy StorageOff-grid Energy Storage

Calculate storage requirements from:Calculate storage requirements from: Climate (periods of cloudy weather?)Climate (periods of cloudy weather?) Critical loads (what do you Critical loads (what do you needneed to power?) to power?) Capacity should last 4 – 21 daysCapacity should last 4 – 21 days

Batteries should not be discharged more Batteries should not be discharged more than 50% – 70% or battery life is shortenedthan 50% – 70% or battery life is shortened

Install batteries in safe, climate-controlled, Install batteries in safe, climate-controlled, ventilated location (not in your living room)ventilated location (not in your living room)

Grid-tied Energy StorageGrid-tied Energy Storage

Most Grid-tied systems do not use Most Grid-tied systems do not use batteriesbatteries

Rather the utility grid is treated as Rather the utility grid is treated as a 100% efficient, unlimited a 100% efficient, unlimited capacity battery (except during capacity battery (except during outages)outages)

Batteries may be added for Batteries may be added for additional storage flexibilityadditional storage flexibility

Batteries: Cost & Efficiency Batteries: Cost & Efficiency ConsiderationsConsiderations

Batteries add significant cost to a PV Batteries add significant cost to a PV systemsystem

Charging batteries significantly reduces Charging batteries significantly reduces system efficiency: 20% energy losses are system efficiency: 20% energy losses are typical during battery chargingtypical during battery charging

“The Xantrex XS12205 12-volt, 184 amp hour, AGM battery was designed for backup and solar applications.”

$399 (list) or $179 (on sale)http://www.partsonsale.com/xs12200.html

Photovoltaic Hardware Photovoltaic Hardware SelectionSelection

PV ModulesPV Modules Inverters & Charge Inverters & Charge

ControllersControllers Mounting HardwareMounting Hardware Balance of System Balance of System

ComponentsComponents

Photovoltaic Modules – Photovoltaic Modules – Selection CriteriaSelection Criteria

Cell types Cell types (in decreasing order of price and (in decreasing order of price and efficiency)efficiency) MonocrystallineMonocrystalline PolycrystallinePolycrystalline Amorphous (thin-film)Amorphous (thin-film)

PerformancePerformance IV curvesIV curves Maximum power ratingMaximum power rating efficiencyefficiency

AestheticsAesthetics

Module Comparison ChartModule Comparison Chart

Photovoltaic Modules – Photovoltaic Modules – Product SurveyProduct Survey

BP Solar: BP 5170 BP Solar: BP 5170 http://www.bpsolar.com/ContentDocuments/84/BP%205170S.pdfhttp://www.bpsolar.com/ContentDocuments/84/BP%205170S.pdf

Shell Solar: SP150-PC Shell Solar: SP150-PC http://www.shell.com/static/shellsolar/downloads/products/us/ShellSP150-PC_UShttp://www.shell.com/static/shellsolar/downloads/products/us/ShellSP150-PC_USv1.pdfv1.pdf

Evergreen Solar: EC-110 Evergreen Solar: EC-110 http://www.evergreensolar.com/egsolar1/pdf/ec100series13.pdfhttp://www.evergreensolar.com/egsolar1/pdf/ec100series13.pdf

Kyocera: KC120-1 Kyocera: KC120-1 http://www.kyocerasolar.com/pdf/specsheets/kc120_1.pdfhttp://www.kyocerasolar.com/pdf/specsheets/kc120_1.pdf

Sharp: NT-S5E1U Sharp: NT-S5E1U http://www.sharpusa.com/files/sol_dow_185WSS.pdfhttp://www.sharpusa.com/files/sol_dow_185WSS.pdf

Inverters – Selection Inverters – Selection CriteriaCriteria

Output typesOutput types True sine waveTrue sine wave Modified sine waveModified sine wave

Input requirementsInput requirements 12VDC, 24VDC, 48VDC12VDC, 24VDC, 48VDC String invertersString inverters PV Modules wired accordinglyPV Modules wired accordingly

Monitoring and data logging capabilitiesMonitoring and data logging capabilities Non-islanding inverters for Grid-tie Non-islanding inverters for Grid-tie

applicationsapplications

- SMA America

Charge ControllersCharge Controllers

Purpose – safe battery Purpose – safe battery chargingcharging

TypesTypes SeriesSeries ShuntShunt

Stand-alone unitsStand-alone units Integrated (into Integrated (into

inverter)inverter)- RV Power Products

Inverter Comparison ChartInverter Comparison Chart

Remote Monitoring Remote Monitoring OptionsOptions

PC Interface: PC Interface: Trace Trace (Xantrex)(Xantrex)

-Home Power Magazine # 94, pgs. 24, 26

PC Interface: SunnyBoyPC Interface: SunnyBoy

- SMA America

Inverters & Charge Inverters & Charge Controllers – Product SurveyControllers – Product Survey

Outback Power SystemsOutback Power Systems http://www.outbackpower.com/http://www.outbackpower.com/

SMA AmericaSMA America http://www.sma-america.com/http://www.sma-america.com/

XantrexXantrex http://www.xantrex.com/products/index.http://www.xantrex.com/products/index.

aspasp

Mounting HardwareMounting Hardware

Two Seas Mounting StructuresTwo Seas Mounting Structureshttp://www.2seas.com/matrix_ground_roof_a_r.htmhttp://www.2seas.com/matrix_ground_roof_a_r.htm

Ground/RoofGround/Roof Flush MountFlush Mount Multi-TierMulti-Tier Low ProfileLow Profile

UniracUnirachttp://www.unirac.com/http://www.unirac.com/

Large Array PV Module Mounting Large Array PV Module Mounting SystemSystem

Solarmount (ground/roof)Solarmount (ground/roof) Tracker 200 (2-module tracking rack)Tracker 200 (2-module tracking rack)

- UniRac

Balance of System Balance of System ComponentsComponents

DC disconnectsDC disconnects AC DisconnectsAC Disconnects Fuses/BreakersFuses/Breakers Grounding hardwareGrounding hardware Lightning ArrestorsLightning Arrestors Combiner BoxesCombiner Boxes

Case StudiesCase Studies

Off Grid LivingOff Grid Living Grid-tied with batteries and monitoringGrid-tied with batteries and monitoring Off Grid PV & Wind Hybrid SystemOff Grid PV & Wind Hybrid System Grid-tied system with unbelievable Grid-tied system with unbelievable

paybackpayback

Off Grid Case Off Grid Case Study: Bisbee Study: Bisbee Family Family – Home Power Magazine #92, pgs. 22-27– Home Power Magazine #92, pgs. 22-27

Grid-tied Case Grid-tied Case Study: Simons Study: Simons Family Family - Home Power Magazine # 94, pgs. 22-27- Home Power Magazine # 94, pgs. 22-27

Off Grid Case Off Grid Case Study: Study: Reising & Reising & McCoy Family McCoy Family - Home Power Magazine #89, pgs. 10-19- Home Power Magazine #89, pgs. 10-19

Grid-tied Case Grid-tied Case Study: Webster Study: Webster Family Family - Home Power Magazine #95, pgs. 22-28- Home Power Magazine #95, pgs. 22-28

Grid-tied Case Grid-tied Case Study: Webster Study: Webster FamilyFamily

Conclusions & Personal Conclusions & Personal ThoughtsThoughts

Carefully designed residential PV Carefully designed residential PV systems provide their owners systems provide their owners with clean, reliable power, and with clean, reliable power, and promote interest in renewable promote interest in renewable energy sources energy sources

Hydrogen as Energy StorageHydrogen as Energy Storage

Building-integrated materialsBuilding-integrated materials

Expanded use of solar energy for Expanded use of solar energy for water purification, water heating, water purification, water heating, space heating (air-to-air heat space heating (air-to-air heat exchangers), as well as exchangers), as well as electricity productionelectricity production -Home Power Magazine # 93, pg. 27

ReferencesReferences• Bell, John (2000). Questions from the Field… [Internet] Available from: <http://www.proaxis.com/~johnbell/iitt/questionftf49.htm> [Accessed July 2003]

• Bisbee, D. (2002) Off the Grid: Starting Small Home Power Magazine, No 92, December/January, pp. 22-23.

• BP Solar (2003). BP Solar Home Page [Internet] Available from: <http://www.bpsolar.com> [Accessed July 2003]

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• Energy Trust (2003). Solar Electric for Homes and Businesses [Internet] Available from: <http://www.energytrust.org> [Accessed July 2003]

• McCoy, C. and Reising, C. (2002) Still Saying "Yes" to Sunshine Home Power Magazine, No 89, June/July, pp. 10-19.

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• Perez, R. and Drake, J. (1997) Where and How to Mount PV Modules. Home Power Magazine, No 57, February/March, pp. 32-37.

• RV Power Products (2003). RV Power Products Home Page [Internet] Available from: <http://www.rvpowerproducts.com> [Accessed July 2003]

• Schaeffer, J. ed. (2001) Solar Living Source Book: The Complete Guide To Renewable Energy Technologies & Sustainable Living. 11th ed. USA,

Chelsea Green Publishing Company.

• Simons, B. (2003) PV Done Right - Grid Tie, Battery Backup, and System Monitoring. Home Power Magazine, No 94, April/May, pp. 22-27.

• SMA-America (2003). SMA-America Home Page [Internet] Available from: <http://www.sma-america.com> [Accessed July 2003]

• Solar Depot (2003). Solar Depot Home Page [Internet] Available from: <http://www.solardepot.com> [Accessed July 2003]

• Solatron Technologies (2003). Xantrex XS12205 [Internet] Available from: <http://www.partsonsale.com/xs12200.html> [Accessed July 2003]

• Two Seas Metalworks (2003). Two Seas Metalworks Home Page [Internet] Available from: <http://www.2seas.com/matrix_ground_roof_a_r.htm> [Accessed July 2003]

• UniRac (2003). Unirac Home Page [Internet] Available from: <http://www.unirac.com> [Accessed July 2003]

• Webster, D. (2003) Getting Off the Lifetime Utility Payment Plan. Home Power Magazine, No 95, June/July, pp. 22-28.

• Xantrex (2003). Products [Internet] Available from: <http://www.xantrex.com/Products/index.asp> [Accessed July 2003]

• Yewdall, Z. (2003) PV Orientation. Home Power Magazine, No 93, February/March, pp. 24-28.