bipv sourcebook

8/7/2019 BIPV sourcebook

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Building-Integrated PhotovoltaicDesigns for Commercial andInstitutional Structures

A Sourcebook for Architects

Patrina Eiffert, Ph.D.Gregory J. Kiss


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AcknowledgementsBuilding-Integrated Photovoltaics for Commercial and Institut ional St ructures: A

Sourcebook for Architects and Engineers was prepared for the U.S. Department ofEnergy's (DOE's) Office of Power Technologies, Photovoltaics Division, and the

Federal Energy Management Program. It was written by Patrina Eiffert, Ph.D.,of the Deployment Facilitation Center at DOEs National Renewable EnergyLaboratory (NREL) and Gregory J. Kiss of Kiss + Cathcart Architects.

The authors would like to acknowledge the valuable contributions of SheilaHayter, P.E., Andy Walker, Ph.D., P.E., and Jeff Wiechman of NREL, and AnneSprunt Crawley, Dru Crawley, Robert Hassett, Robert Martin, and Jim Rannels ofDOE. They would also like to thank all those who provided the detailed designbriefs, including Melinda Humphry Becker of the Smithsonian Institution,Stephen Meder of the University of Hawaii, John Goldsmith of Pilkington SolarInternational, Bob Parkins of the Western Area Power Administration, SteveCoonen of Atlantis, Dan Shugar of Powerlight Co., Stephen Strong and BevanWalker of Solar Design Associates, Captain Michael K. Loose, Commanding

Officer, Navy Public Works Center at Pearl Harbor, Art Seki of Hawaiian ElectricCo., Roman Piaskoski of the U.S. General Services Administration, Neall Digert,Ph.D., of Architectural Energy Corporation, and Moneer Azzam of ASE Americas,Inc.

In addition, the authors would like to thank Tony Schoen, Deo Prasad, PeterToggweiler, Henrik Sorensen, and all the other international experts from theInternational Energy Agencys PV Power Systems Program, TASK VII, for theirsupport and contributions.

Thanks also are due to staff members of Kiss + Cathcart and NREL for theirassistance in preparing this report. In particular, we would like to acknowledgethe contributions of Petia Morozov and Kimbro Frutiger of Kiss + Cathcart, andRiley McManus, student intern, Paula Pitchford, and Susan Sczepanski of NREL.

On the cover: Architects rendering of the HEW Customer Center in Hamburg, Germany,showing how a new skin of photovoltaic panels is to be draped over its facade and forecourt(architects: Kiss + Carthcart, New York, and Sommer & Partner, Berlin).

Building-Integrated Photovoltaics for Commercial and Institutional Structure


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Building-Integrated Photovoltaics for Commercial and Institutional Structures

ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Design Briefs

4 Times Square . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Thoreau Center for Sustainability . . . . . . . . . . . . . . . . . . . . . . . . . . .7

National Air and Space Museum . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Ford Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Western Area Power Administration . . . . . . . . . . . . . . . . . . . . . . .24

Photovoltaic Manufacturing Facility . . . . . . . . . . . . . . . . . . . . . . .28

Yosemite Transit Shelters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Sun Microsystems Clock Tower . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

State University of New York, Albany . . . . . . . . . . . . . . . . . . . . . .38

Navajo Nation Outdoor Solar Classroom . . . . . . . . . . . . . . . . . . . .40

General Services Administration, Williams Building . . . . . . . .42

Academy of Further Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

Discovery Science Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48

Solar Sunflowers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50Ijsselstein Row Houses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

Denver Federal Courthouse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

BIPV Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

BIPV Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70

Appendix A: International Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . .71

Appendix B: Contacts for International Energy AgencyPhotovoltaic Power Systems Task VIIPhotovoltaics in theBuilt Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77

Appendix C: Design Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78

About the Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88


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IntroductionBuilding-integrated photovoltaic (BIPV) electric power systems not only produce electricity, they

are also part of the building. For example, a BIPV skylight is an integral component of the building

envelope as well as a solar electric energy system that generates electricity for the building. These

solar systems are thus multifunctional construction materials.

The standard element of a BIPV system is the PV module. Individual solar cells are interconnected

and encapsulated on various materials to form a module. Modules are strung together in an

electrical series with cables and wires to form a PV array. Direct or diffuse light (usually sunlight)

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 or exported to a utility company through a grid interconnection.

A wide variety of BIPV systems are available in today's markets. Most of them can be grouped

into two main categories: facade systems and roofing systems. Facade systems include curtain

wall products, spandrel panels, and glazings. Roofing systems include tiles, shingles, standing

seam products, and skylights. This sourcebook illustrates how PV modules can be designed as

aesthetically integrated building components (such as awnings) and as entire structures (such as

bus shelters). BIPV is sometimes the optimal method of installing renewable energy systems in

urban, built-up areas where undeveloped land is both scarce and expensive.

The fundamental first step in any BIPV application is to maximize energy efficiency within the

buildings energy demand or load. This way, the entire energy system can be optimized.

Holistically designed BIPV systems will reduce a buildings energy demand from the electric

utility grid while generating electricity on site and performing as the weathering skin of thebuilding. Roof and wall systems can provide R-value to diminish undesired thermal transference.

Windows, skylights, and facade shelves can be designed to increase daylighting opportunities

in interior spaces. PV awnings can be designed to reduce unwanted glare and heat gain. This

integrated approach, which brings together energy conservation, energy efficiency, building

envelope design, and PV technology and placement, maximizes energy savings and makes the

most of opportunities to use BIPV systems.

It is noteworthy that half the BIPV systems described in this book are on Federal buildings. This is

not surprising, however, when we consider these factors: (1) the U.S. government, with more than

half a million facilities, is the largest energy consumer in the world, and (2) the U.S. Department

of Energy (DOE) has been directed to lead Federal agencies in an aggressive effort to meet the

governments energy-efficiency goals. DOE does this by helping Federal energy managers identify

and purchase the best energy-saving products available, by working to increase the number and

quality of energy projects, and by facilitating effective project partnerships among agencies,

utilities, the private sector, and the states.

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Because it owns or operates so many facilities, the U.S. government has an enormous number of

opportunities to save energy and reduce energy costs. Therefore, the Federal Energy Management

Program (FEMP) in DOE has been directed to help agencies reduce energy costs, increase their

energy efficiency, use more renewable energy, and conserve water. FEMP's three major work areas

are (1) project financing; (2) technical guidance and assistance; and (3) planning, reporting, and

evaluation.

To help agencies reach their energy-reduction goals, FEMPs SAVEnergy Audit Program identifies

cost-effective energy efficiency, renewable energy, and water conservation measures that can be

obtained either through Federal agency appropriations or alternative financing. FEMP's national,

technology-specific performance contracts help implement cutting-edge solar and other renewable

energy technologies. In addition, FEMP trains facility managers and showcases cost-effective

applications. FEMP staff also identify Federal market opportunities and work with procurement

organizations to help them aggregate purchases, reduce costs, and expand markets.

All these activities ultimately benefit the nation by reducing building energy costs, saving taxpayers

money, and leveraging program funding. FEMPs activities also serve to expand the marketplace

for new energy-efficiency and renewable energy technologies, reduce pollution, promote

environmentally sound building design and operation, and set a good example for state and local

governments and the private sector.

This sourcebook presents several design briefs that illustrate how BIPV products can be integrated

successfully into a number of structures. It also contains some basic information about BIPV and

related product development in the United States, descriptions of some of the major software design

tools, an overview of international activities related to BIPV, and a bibliography of pertinentliterature.

The primary intent of this sourcebook is to provide architects and designers with useful information

on BIPV systems in the enclosed design briefs. Each brief provides specific technical data about the

BIPV system used, including the systems size, weight, and efficiency as well as number of inverters

required for it. This is followed by photographs and drawings of the systems along with general

system descriptions, special design considerations, and mounting attachment details.

As more and more architects and designers gain experience in integrating photovoltaic systems

into the built environment, this relatively new technology will begin to blend almost invisibly into

the nations urban and rural landscapes. This will happen as BIPV continues to demonstrate acommercially preferable, environmentally benign, aesthetically pleasing way of generating

electricity for commercial, institutional, and many other kinds of buildings.

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Close-up view of curtain wall illustrates that BIPV panels (dark panels) can be mountedin exactly the same way as conventional glazing (lighter panels).

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4 design briefs: 4 Times Squa

4 Times Square

Location: Broadway and 42nd Street, New York City, New York

Owner: Durst Corporation

Date Completed: September 1999

Architect & Designer: Fox & Fowle Architects, building architects;Kiss + Cathcart Architects, PV system designers

PV Structural Engineers: FTL/Happold

Electrical Engineers: Engineers NY

Tradesmen Required: PV glazing done by shop labor at curtain wall fabricator

Applicable Building Codes: New York City Building Code

Applicable Electric Codes: New York City Electrical Code and National Electric Code

PV Product: Custom-sized BIPV glass laminate

Size: 14 kWp

Projected System Electrical Output: 13,800 kWh/yr

Gross PV Surface Area: 3,095 ft2

PV Weight: 13.5 lb/ft2

PV Cell Type: Amorphous silicon

PV Module Efficiency: 6%PV Module Manufacturer: Energy Photovotaics, Inc.

Inverter Number and Size: Three inverters; two 6 kW (Omnion Corp.), one 4 kW (Trace Engineering)

Inverter Manufacturers: Omnion Corp. and Trace Engineering

Interconnection: Utility-Grid-Connected

Kiss+Cathcart,Architects/PIX08458


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DescriptionThe tallest skyscraper built in New YorkCity in the 1990s, this 48-story office towerat Broadway and 42nd Street is a some-what unusual but impressive way todemonstrate "green" technologies. Its

developers, the Durst Organization, wantto show that a wide range of healthybuilding and energy efficiency strategiescan and should be incorporated into realestate practices.

Kiss + Cathcart, Architects, are consul-tants for the building towers state-of-the-art, thin-film BIPV system. Working incollaboration with Fox and Fowle, archi-tects for the base building, Kiss + Cathcarthave designed the BIPV system to func-tion as an integral part of the tower's

curtain wall. This dual use makes it oneof the most economical solar arraysever installed in an urban area. EnergyPhotovoltaics of Princeton, New Jersey,developed the custom PV modules tomeet rigorous aesthetic, structural, andelectrical criteria.

Traditionally, solar technologies havebeen considered economical only inremote areas far from power grids or inareas with an unusually high amount ofsunlight. Advances in PV efficiency are

overturning these assumptions, allowingsolar electricity to be generated cost-effectively even in the heart of the city.In fact, PV is the most practical means ofgenerating renewable electricity in anurban environment. Further, BIPV can bedirectly substituted for other claddingmaterials, at a lower material cost thanthe stone and metal it replaces. As thefirst major commercial application ofBIPV in the United States, 4 Times Squarepoints the way to large-scale productionof solar electricity at the point of greatest

use. The next major market for PV maywell be cities like New York that have bothhigh electricity costs and high-qualitybuildings.

Special Design Considerations

The south and east facades of the 37ththrough the 43rd floor were designatedas the sites for the photovoltaic "skin."BIPV was incorporated into the designafter the towers general appearancehad already been decided upon, so the

design briefs: 4 Times Square

BIPV panels have beenintegrated into thecurtain wall instead ofconventional glassspandrel panels on the37th through the 43rdfloor.

The custom-made BIPVpanels are visible in thissidewalk view fromBroadway.

Kiss+Cathc

art,

Architects/PIX06457

Kiss+Cathcart,

Architects/PIX

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installation was made to harmonize withthe established design concept.

PV System ConfigurationThe PV modules replace conventionalspandrel glass in the south and east

facades. There are four different sizesof modules, and they correspond to thespandrel sizes established earlier in thedesign process.

PV Module Mounting andAttachment DetailsThe PV modules are attached to the build-ing structure in exactly the same way thatstandard glass is attached. The glassunits are attached with structural siliconeadhesive around the back edge to an alu-minum frame. An additional silicone bead

is inserted between the edges of adjacentpanels as a water seal.

There is a separate electrical system foreach facade. Each system consists of twosubsystems, feeding two 6-kW invertersand one 4-kW inverter. The larger invert-ers serve the two large-sized PV modules,which have electrical characteristics thatare different from those of the smallerones. Using multiple inverters enables thesystem to perform more efficiently. Theinverters are located in a single electrical

closet at the core of the building. The ACoutput of the inverters is transformedfrom 120 V to 480 V before being fed intothe main electrical riser.

6 design briefs: 4 Times Squar

4 Times Square during construction


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Location: Presidio National Park, Building 1016, San Francisco, California

Owner: U.S. Department of Interior, National Park Service

Date Completed: May 1996

Architect & Designer: Tanner, Leddy, Maytum, Stacy

Structural and Electrical Engineers: Equity Builders

Tradesmen Required: Glaziers

Applicable Building Codes: California structural and seismic codes

Applicable Electric Codes: National Electric Code

PV Product: Roof-integrated, translucent glass-laminate skylight

Size: 1.25 kWp

Projected System Electrical Output: 716.4 kWh/yr/AC

Gross PV Surface Area: 215 ft2

PV Weight: 8 lb/ft2

PV Cell Type: Polycrystalline silicon

PV Efficiency: 11% cell, 7% modulePV Module Manufacturer: Solar Building Systems, Atlantis Energy

Inverter Size: 4 kW

Inverter Manufacturer and Model: Trace Engineering Model 4048


design briefs: Thoreau Center for Sustainability

Thoreau Center for Sustainability

Presidio National Park, Building 1016

The first application forintegrating photovoltaicsinto a Federal building is theskylighted entryway of theThoreau Center in PresidioNational Park.


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DescriptionThe Greening of the Presidio demon-strates the impact of successful partner-ships between the private and publicsector. The Thoreau Center for Sustain-ability is a historic building, located in the

National Historic Landmark District of thePresidio in San Francisco, California. Thegoal of transforming this historic buildinginto an environmentally responsive struc-ture produced an opportunity to applyprinciples of sustainable design andarchitecture and educate the public aboutthem. Within this building rehabilitationproject, materials selected for the renova-tion included recycled textile materials,recycled aluminum, recycled newsprint,recycled glass, and wood grown andharvested sustainably.

The environmentally friendly strategyincluded reducing energy consumptionthrough a Demand Side Management(DSM) Program with the local utility com-pany, PG&E. The building has a highly effi-cient direct/indirect lighting system withtranslucent office panels to allow innerzones to borrow daylight from the perime-ter. The building is heated by an efficientmodular boiler and is cooled by naturalventilation. The BIPV system is a highlyvisible sustainable building feature. The

demonstration of this power system byDOE FEMP, the National RenewableEnergy Laboratory (NREL), and numerousprivate-sector partners illustrates thatBIPV is a technically and economicallyvaluable architectural element fordesigners.

The skylit entryway of the Thoreau Centerfor Sustainability at Presidio NationalPark was the first demonstration in theUnited States of the integration of photo-voltaics into a federal building. Laminated

to the skylight glass are photovoltaic cellsthat produce electricity and also serveas a shading and daylighting design ele-ment. Atlantis Energy provided custom-manufactured PV panels and the systemdesign and integration for this project.The firm was joined by constructionspecialists who made it possible totransform this historic building into anenvironmentally responsive structure.

The solar electricity generated in thePV system in the skylight offsets power

provided by the utility, thereby conservingfossil fuels and reducing pollution.Converting the DC electricity to AC, thesystem can produce about 1300 wattsduring periods of full sun. The systemis fully automatic and requires virtuallyno maintenance. Like other PV systems,

it has no moving parts, so this solargenerating system provides clean, quiet,dependable electricity.

The entry area into the Thoreau Center isa rectangular space with a roof slopingslightly to the east and west. The roof isconstructed entirely of overhead glazing,similar to a large skylight. PV cells arelaminated onto the 200 square feet ofavailable overhead glazing to produceapproximately 1.25 kW of electricity understandard operating conditions. The PV-

produced DC electric power is convertedto high-quality AC by a power-conditioningunit (inverter). After it is converted, thepower enters the building to be consumedby the buildings electrical loads.

Special Design ConsiderationsDesign and construction issues for therelatively small Thoreau Center systemwere similar in many ways to issuesinvolved with designing and constructingmuch larger systems. The panels for this

project were custom-manufactured byAtlantis Energy to meet the estheticrequirements of the architect. The squarpolycrystalline PV cells are spaced farenough apart from one another to permidaylighting and provide pleasant shad-ows that fall within the space. The amou

of daylight and heat transfer throughthese panels was considered in determining the lighting and HVAC requirementsfor the space. The panels themselveswere constructed to be installed in a stadard overhead glazing system framewor

The system is installed above seismic-code-approved skylight glazing. The daylighting and solar gains through the PVmodules mounted above the skylight sytem do affect the building lighting andHVAC loads, but the modules do not also

serve as the weathering skin of this building envelope. Originally, the design callefor the PV modules to replace the skylighunits. But during design approval, localbuilding code authorities were uncertainwhether the modules could meet seismicode requirements. So the alternativedesign, stacking the skylights and themodules, was used instead.

To ensure that the glazing used in manu-facturing the PV panels was acceptableaccording to Uniform Building Codes

8 design briefs: Thoreau Center for Sustainabili

The PV arrays produce electricity and serve as a daylighting designelement.


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design briefs: Thoreau Center for Sustainability

This schematic drawing shows how the PV modules were attached above the conventional skylight glazing.

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(UBC), building code issues wereaddressed. Special arrangements weremade with the local electrical utility toensure that the grid-tied system wouldmeet safety requirements. Finally,installing the system required coordina-tion between the panel supplier, electri-cian, glass installer, and Presidio facilitiespersonnel.

PV System ConfigurationThe BIPV glazing system consists of 24 PVglass laminates. The spacing of the cellswithin the modules allows approximately17% of the sunlight into the entryway,reducing the need for electric lights. Themodules consist of 6-mm Solarphireglass, 36 polycrystalline silicon PV cells,

an ethylene-vinyl acetate coating, atranslucent Tedlar-coated polyester back-sheet, and two sealed and potted junctionboxes with a double pole plug connector.The PV cells are laminated in a 6-cell x 6-cell matrix. The minimum spacingbetween cells is 1.25 cm (1/2 in.). Thedimension of each module is 81 cm x94 cm (32 in. x 37 in). The gross area ofthe entire structure is 18.8 m2 (200 ft2).

The power produced by the system is con-verted to high-quality AC electricity andsupplements power supplied to the build-ing by the utility. The system is rated at1.25 kW. Each of the 24 PV modules gen-erates 8.5 V of DC power at approximately5.5 amps. Six modules per sub-array are

connected in series to feed the sine-wavinverter, which is configured to 48 V andrated at 4,000 W capacity.

PV Module Mounting andAttachment DetailsStructural upgrades were made to accommodate the additional weight of the PVsystem. These added about $900 to thetotal cost, for structural components.

10 design briefs: Thoreau Center for Sustainabili

This drawing shows how the photovoltaic skylight array was arranged. The total array area is 20.6 square meters


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design briefs: National Air and Space Museum

National Air and Space Museum

Location: Dulles Center, Washington, DC

Owner: Smithsonian Institution

Date Completed: Construction begun in 2000, scheduled for completion in 2003

Architect & Designer: HOK, Building Architects; Kiss + Cathcart Architects, PV System Designers;Satish Shah, Speigel, Zamel, & Shah, Inc.

Structural Engineers: N/A

Electrical Engineers: N/A

Tradesmen Required: Building tradesmen

Applicable Building Codes: BOCA, Metropolitan Washington Airport Authority


PV Product: Various BIPV systems

Size: To be determined for BIPV curtain wall, facades, and canopy

Projected System Electrical Output: 15.12 kWh for the canopy system

Gross PV Surface Area: 223 m2 for the canopy system

PV Weight: 5 lb/ft2 for the canopy system

PV Cell Type: Polycrystalline cells, amorphous silicon film for various systems

PV Efficiency: Systems will range from 5% to 12%PV Module Manufacturer: Energy Photovoltaics, Inc., for the

canopy system

Inverter Number and Size: To be determined

Inverter Manufacturer & Model: To be determined


Project OvervieAxonometr

PV CanopyPV Curtain Wall

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The BIPV installations at theentryway will demonstratedifferent BIPV systems andtechnologies, such as thinfilms and polycrystallinesolar cells.


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The south- and west-facing facades of the entry hall will be glazed with polycrystalline glass laminates.


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standards for collections managementand the display of large, 20th-centuryfunctional objects.

Smithsonian staff are evaluating the inte-gration of a number of grid-connectedBIPV systems into the building. The NASMDulles Center will be a very large structure(740,000 ft2), with commensurate energy

and water requirements. As part of itseducational mission, the museum plansto exhibit hardware that points to thehistoric use of photovoltaic (PV) powersystems in space; the museum wouldalso like to demonstrate how that tech-nology can be used today in terrestrialapplications such as BIPV. To this end,the Smithsonian is evaluating the highlyvisible application of BIPV at this facilityto meet a portion of its energy require-ments. In this way, two objectives will be

met: (1) reduce the amount of energyrequired from the power grid, especiallyduring peak times, and thus conserveenergy and save operational funds, and(2) demonstrate the use of PV in a highlyvisible context in a much-visited Federalfacility.

Five BIPV subsystems could be demon-

strated at the new NASM facility, includingthe south wall and skylight of the entry"fuselage," the roof of the restorationhangar and space shuttle hangar, thefacade of the observation tower, andawning canopies. The entry fuselagefigure clerestory windows will be a highlyvisible way of demonstrating PV to visi-tors approaching the center. Once in theentryway, visitors would also see thepatterns of shadow and light the frittedglass creates on the floor, thus focusing

visitors attention on the PV. Labels,exhibit material, and museum tour staffcould further highlight the PV arrays andcall attention to the energy savings beinrealized. PV would also be used to powesome exhibit material exclusively. Therelated exhibit materials could highlightthe many connections between PV and

the field of space exploration and utilization, as well as todays construction andbuilding industry.

14 design briefs: National Air and Space Museu

BIPV Canopy detail 1:10

Canopy:Structural Details

BIPV Canopy - section 1:60

02527219m

Thin-film BIPV glasslaminates will functionas the canopy.


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Fuselage detail illustrates patterns of polycrystalline glazing.


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Curtain wall details indicate how mullion channels will act as electrical conduits.


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The canopy plan and perspective demonstrate how shading and power output are combined in one architecturalexpression.


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Curtain walls typically will be 16 polycrystalline solar cells per panel, laminated between two clear glass panes.


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design briefs: Ford Island 1

Ford Island

Building 44, Pearl Harbor Naval Station

This illustration is a view of the building from the southwest corner; the dark areasrepresent the photovoltaic standing-seam metal roofing material.

Location: Honolulu, Hawaii

Owner: U.S. Navy, Department of Defense, and Hawaiian Electric Company

Date Completed: September 1999

Architect & Designer: Victor Olgyay, Fred Creager, and Stephen Meder, University of Hawaii, School ofArchitecture

Structural Engineers: Hawaiian Electric Co.

Electrical Engineers: Hawaiian Electric Co.; Peter Shackelford, Renewable Energy Services, Inc., system integrator

Tradesmen Required: Roofers, electrical contractors

Applicable Building Codes: Uniform Building Code


PV Product: Integrated standing seam metal roof

Size: 2.8 kW DC

Projected System Electrical Output: 9,720 kWh per month


PV Weight: 4 lb/ft2, with the roof

PV Cell Type: Multijunction amorphous silicon

PV Module Efficiency: 5%-6%

PV Module Manufacturer: Uni-Solar

Inverter Number and Size: One, 4-kW

Inverter Manufacturer and Model: Trace SW 4048PV


02527213m


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DescriptionA partnership consisting of the U.S. Navy,Hawaiian Electric Co. (HECO), theUniversity of Hawaii, the U.S. DOE FederalEnergy Management Program (FEMP),and the Utility PhotoVoltaic Group (UPVG)was created in order to design and installa 2-kW, grid-intertied, BIPV retrofit sys-tem using the Uni-Solar standing seam

metal roofing product and to monitor itsperformance for one year. The Universityof Hawaii School of Architecture designedand administered the project and a localutility, HECO, funded it. Additional con-struction cost support was supplied byFEMP, NREL, and the Navy. The utility andthe Navy determined the site, and theinstallation date was scheduled for thethird quarter of 1998 (Figure 1). HECO wasdesignated to be the client for the firstyear, after which the Navy will assumeownership of the system.

The tropical location (21 North) and thesites microclimate make it an ideal loca-tion for PV installations. Project plannersexpected an annual daily average of5.4 peak sun hours and 20 to 25 in.(57 cm) of annual rainfall. This project, atthis particular site, will also be testing thelimits of the products used in the installa-tion. Monitoring the performance of the

PV system, the McElroy metal substrate,and the Trace inverter in a tropical marineenvironment will provide valuable perfor-mance information to guide the futuredevelopment and use of these products.

The total cost of this project was $92,000.This included design, procurement, roofremoval and BIPV installation, and a yearof monitoring.

Special Design ConsiderationThe context of this project is the navalindustrial site at Pearl Harbor NavalBase.The site contained a 90 ft x 52 ft(27.4 m x 15.8 m) open-wall boathousestructure. The existing roof of the struc-ture was made of box rib metal on trusse(Figure 2) in gable form, divided longitudnally on its east-west axis. The south

20 design briefs: Ford Islan

In this illustration, the dark areas represent amorphoussilicon laminates on standing seam metal roofing panels.

The array in mid-installation is shaded only by cloud cover.

PIX08475


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slope provides a 90 ft x 26 ft (27.4 m x7.9 m) surface at a 5 incline. This half

of the roof measured approximately2,340 ft2 (217 m2). The box rib roofingwas removed from the entire south-facingslope, and new standing seam pans,including 24 of the Uni-Solar SSR 120photovoltaic standing seam panels,replaced the original roofing.

Integrating the new metal roofing withthe existing roof posed several designand construction challenges. In addition,the longest panel that Uni-Solar could

provide is 20 ft (6.09 m) and the requiredrun is 26+ ft (8 m). This shortfall required

overlapped joints to be used on the endsof the panels and additional purlinesto be welded for support. Full-length,standing-seam panels and non-PV panelswere set in an alternating pattern withthe PV modules. This arrangementallowed the full-length pans to addstrength over the required lap joint ofthe shorter PV units.

The length limitation of the Uni-Solarpanels was a design deficiency of the

Uni-Solar product; unless new PV-to-metal laminating processes are devel-oped, this product will be substantiallylimited in metal roofing applications.

Joining the panels to extend their lengthnot only increases material and labor

costs, it also provides opportunities forwater penetration and corrosion. The"galvalum" coating is cut away every-where the panel is modified. This exposethe steel of the standing seam panel tothe marine environment. Therefore,McElroy, Uni-Solars metal roof supplier,will not warranty the product for marineapplications.

In addition, to match the paint of theexisting structure, McElroy required aminimum order to custom-paint the newroof panels. Therefore, about one-thirdmore roofing panels had to be purchasethan were needed, and this increased thoverall project cost. The extra panelsturned out to be useful, however, sincemany were damaged during transport toHawaii.

The part of the roof to be retrofitted spana dock area below. This presented staginchallenges for the roofing and electricalcontractors. Along with restricted accessto the military base and the need to takebridge to the site, the location of the roo

added to the complexity and costs of theproject. And the harsh marine environ-ment could have a corrosive effect on tharray and its components.

PV System ConfigurationThe system is rated at 2.175 kW AC(2.8 kW DC). The estimated system out-put is 9,720 kWh per month. The buildinis not independently metered. It is fed bythe Pearl Harbor grid, to which HECO suplies power. The estimated demand of thbuilding is about 12000 kWh per month.The energy generated by the PV systemwill feed but not meet the average loadsof this building.

PV Module Mounting andAttachment DetailsIntegrated connection follows standardmetal seam roof attachment process.Notched PV panels are secured to non-Ppanels with metal fasteners.

design briefs: Ford Island

This illustration shows how the notched BIPV standing-seam componentsoverlap the regular roofing panels.


24/92

22 design briefs: Ford Islan

Junction box at ridge, viewed from below

PIX08478

Junction box at ridge, viewed from above

Additional electrical junction boxes were required overpotted terminals and raceways at the ridge, before the

ridge cap was installed.

Workers install short lapped roofing pans at BIPVmodule sections.

PIX08476


25/92

design briefs: Ford Island 2

The part of the roof containing BIPV spans a dock area, as shown in this illustration.

0 2 5 2 7 2 8 9


26/92

des

ignb

riefs

24 design briefs: Western Area Power Administratio

Western Area Power Administration

Elverta Maintenance Facility, Phases I and IIPhase I

Location: Elverta, California

Owner: U.S. Department of Energy (DOE) Western Area Power Administration

Date Completed: May 1996Architect & Designer: DOE Western Area Power Administration, PowerLight Corporation

System Integrator: PowerLight Corporation

Structural Engineers: DOE Western Area Power Administration

Electrical Engineers: DOE Western Area Power Administration

Tradesmen Required: Roofers, electrical contractors

Applicable Building Codes: Standard California building codes


PV Product: PowerGuard BIPV roof tiles

Size: 40 kW DC

Projected System Electrical Output: 70,000 kWh/year


PV Weight: 4 lb/ft2


PV Efficiency: 12%

PV Module Manufacturer: Solarex

Inverter Number and Size: 8 inverters, 6 kW each

Inverter Manufacturer: Omnion Corp.


PIX0

8451

A 38-kW BIPV system supplements a40-kW system installed in 1996.

Phase I

Phase II


27/92

DescriptionStaff in the Department of EnergysWestern Area Power AdministrationSierra Nevada Region (SNR) have had twomain goals for SNR's photovoltaic (PV)program: (1) promote PV systems as a

renewable energy resource, and (2) doso in a cost-effective manner. In supportof these goals, SNR has incorporatedPV panels into the roofs of buildings inElverta and Folsom, California. The build-ing-integrated systems will repay invest-ments in them by extending roof lives,reducing maintenance costs, generatingelectric power, and reducing the build-ings' cooling requirements.

In Phase I, a 40-kW building-integratedphotovoltaic system was installed at

SNR's Elverta Maintenance Facility. TheSacramento Municipal Utility District(SMUD) funded the PowerLight Corp.PowerGuard system, while Westerncontributed funds equivalent to the costof replacing the facility roof. Funding wasalso provided by the Utility PhotovoltaicGroup (UPVG) through TEAM-UP, withsupport from the U.S. Department ofEnergy.

With a power capacity of 40 kW peak DCand an annual energy output of more

than 70,000 kWh/year, the PV systemshave significant environmental benefits.Phase I prevents the emission of2,300 tons of carbon dioxide, 8.7 tonsof nitrogen oxides and 16.4 tons of sulfurdioxides; these emissions would be theresult if fossil fuels were burned togenerate the same amount of electricity.Because this system is designed to havea life expectancy of 20 years, the cumula-tive benefits for the environment aremany.

Special Design ConsiderationsPowerGuard PV tiles were used to reroofthe building, saving on the cost of con-ventional roofing material. The patentedPowerGuard tiles incorporate high-effi-ciency polycrystalline silicon cells fromSolarex. Site conditions were favorablefor this sytem: 38 latitude; a dry, sunnyclimate throughout most of the year; andno shading. The system features horizon-tal tiles and tiles with an 8 southerly tilt

for greater annual energy production. In

addition to generating clean renewableenergy, the lightweight system providesR10 roof insulation for improved buildingcomfort and membrane protection forextended roof life. Installation took only7 days to complete once the building'sold roof was replaced with a new single-ply membrane roof.

PV System ConfigurationA 40-kW PowerGuard building-integratePV system was installed at the ElvertaMaintenance Facility in Western's SierraNevada Region to function as both a rooand solar electric photovoltaic (PV) powplant. Phase I modules were installed inparallel strings containing 56 modules pstring (7 series, 8 parallel).

design briefs: Western Area Power Administration 2

A view of the rooftop of the Elverta facility after the PV system installatio

A PowerLight rooftop PV system is installed on Westerns facility inElverta, California.


28/92

PV Module Mounting andAttachment DetailsThe panels are designed to interlockusing a tongue-and-groove assembly.Panels with 3/8-in. concrete topping,instead of PV modules, are set amongthe PV panels to allow working accessthroughout the roof. Along the edgesof the PV array, a steel ribbon links the

modules together, in order to connecteverything structurally.

26 design briefs: Western Area Power Administratio

The temperature curves show how the PV-integrated roof compares with various roofs without solar electricsystems. Roof-integrated PV with integral insulation reduces a buildings heat load as much as 23C. Themeasurements were derived from sensors placed in representative roof specimens.

02527230m

Workers carry PV modules with attached foam backing in preparation forrooftop mounting. Smaller panels with concrete topping were alsoinstalled as a walking surface.


29/92

DescriptionThis 38-kW BIPV system supplements thePhase I system. Both systems completelycover the Elverta roof and are the largestPV application of its kind in the UnitedStates. Phase II is totally funded andowned by Western. The PV systems utilizethin-film amorphous silicon technology.The DC output from the PV modules isconverted to 240 V AC by means of acustom-built 32-kW Trace inverter, andthen stepped up to 480 V, three-phaseAC by a 45-kVA transformer for directconnection to the building's servicepanel. Besides replacing grid power, thePowerlight system protects the roof

membrane, which extends its life. The roofsystem also provides R10 insulation toreduce cooling and heating loads, therebydecreasing energy consumption.

Special Design ConsiderationsThe flush roof design provides excellentinsulation as well as electricity, as shownin the graph comparing roof temperaturedata.

PV System ConfigurationThe Solarex modules were installed in254 parallel strings, with three Solarexmodules in series per string. The modules

produce 43 watts each. The APS modulewere installed in 22 parallel strings with12 modules in series per string. The APSmodules produce 22 watts each.

PV Module Mounting andAttachment DetailsSame as those for Phase I.

design briefs: Western Area Power Administration 2

The illustration shows how the layers in the roofs provide above-averageinsulation as well as a good base for the PowerGuard PV system.

RoofingMembrane

Solar ElectricPanel

StyrofoamInsulation

Substrate Roof Deck 02527234m

Phase IILocation: Elverta, California

Owner: U.S. Department of Energy (DOE) Western Area Power Administration

Date Completed: June 1998

Architect & Designer: DOE Western Area Power Administration, PowerLight Corporation

System Integrator: PowerLight CorporationStructural Engineers: DOE Western Area Power Administration

Electrical Engineers: DOE Western Area Power Administration

Tradesmen Required: Electrical and building contractors

Applicable Building Codes: Standard California building codes


PV Product: PowerGuard BIPV roof tiles

Size (kWp): 38 kW DC

Projected System Electrical Output: 67,500 kWh/year


PV Weight: 5 lb/ft2

PV Cell Type: Thin-film amorphous silicon

PV Efficiency: 4%-5%

PV Module Manufacturer: Solarex (762 modules) and APS (264 modules)

Inverter Number and Size: One 32-kW AC

Inverter Manufacturer and Model: Trace Technologies


Phase I

Phase II


30/92

des

ignbriefs

28 design briefs: Photovoltaic Manufacturing Facilit

Photovoltaic Manufacturing Facility

Location: Fairfield, California

Owner: BP Solar

Date Completed: 1993

Architect & Designer: Kiss Cathcart Anders, Architects

Structural Engineers: Ove Arup & Partners

Electrical Engineers: Ove Arup & PartnersTradesmen Required: Glaziers, electricians

Applicable Building Codes: BOCA and California Title 24


PV Product: Glass laminates as curtain wall spandrel, skylight, and awning

Size: 9.5 kWp

Projected System Electrical Output: 7.9 kW


PV Weight: 3 lb/ft2


PV Efficiency: 5%

PV Module Manufacturer: APS

Inverter Number and Size: 6 kW

Inverter Manufacturer: Omnion Corporation


Views looking north (top) and south show how BIPV is integrated into both the facade and thecanopy that runs the length of the building.


31/92

DescriptionCompleted in 1993, this 69,000-ft2 manu-facturing facility houses a new generationof production lines tailored to thin-film

PV technology. The building also incorpo-rates into its design several applicationsof thin-film solar modules that are proto-types of BIPV products.

The heart of the project is a 22.5-ft-highBIPV glass cube containing the factoryscontrol center and visitor facilities. Thiscube is perched on the second floor, andhalf of it is outside of the manufacturingbuilding, emphasizing its status as anindependent element and a prototype

that demonstrates BIPV in a typical commercial building. The cubes PV claddingthe solar entrance canopy, and the translucent BIPV skylight provide more thanenough energy to power the controlcenters lighting and air-conditioning

systems.The production floor and warehousespace are housed in a tilted-up concreteshell with a steel intermediate structureand a timber roof. Glass blocks embeddeas large-scale "aggregate" in the outsidwalls provide a pattern of light in the interior during the day and on the exterior anight. Mechanical service elements arecontained in a low, steel-framed structuron the north side of the building. Theentry court is paved in a pattern of tintedconcrete and uplighting that representsan abstracted diagram of solar energygeneration.

Special Design ConsiderationIn addition to providing a working produdevelopment test bed for BIPV systems,the project serves an educational functiofor public and private groups. Thelobby/reception area provides displayspace for products and research. A pat-tern cast into the paving in front of themain entry combines a sun path diagram

with a representation of the photovoltaieffect at the atomic level. The controlroom/cube also serves an educational

design briefs: Photovoltaic Manufacturing Facility 2

Interior view shows how BIPV isused with vertical and slopedglazing.

PIX08447

This office interior view demonstrates the quality of light transmittedby the approximately 5% translucent BIPV panel skylight.

PIX08448


32/92

30 design briefs: Photovoltaic Manufacturing Facili

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02527210m


33/92

design briefs: Photovoltaic Manufacturing Facility

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02527206m


34/92

32 design briefs: Photovoltaic Manufacturing Facili

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02527208m

Sectional view indicates skylight configuration and curtain-wall facade.


35/92


36/92

des

ignbriefs

34 design briefs:Yosemite Transit Shelt

Yosemite Transit Shelters

The transit shelter prototype makes use of both high-tech and low-tech materials, combininglocally forested lumber with BIPV panels.

02527238m

Location: Yosemite National Park, California

Owner: U.S. Department of Interior, National Park Service

Date Completed: Scheduled for system completion in 2001

Architect & Designer: Kiss + Cathcart, Architects

Structural Engineers: Ove Arup & Partners, Structural Engineers

Electrical Engineers: None; design overview provided by inverter manufacturerTradesmen Required: Standard Contractor/Carpenter and Electrician

Applicable Building Codes: National Park Service, self-regulating

Applicable Electrical Codes: National Park Service, self-regulating

PV Product: Amorphous silicon glass panels

Size: 560 Wp per transit shelter

Projected System Electrical Output: 1.15 MWh/yr




PV Efficiency: 6%

PV Module Manufacturer: Energy Photovoltaics, Inc.

Inverter Numbers and Size: 1 kW

Inverter Manufacturer: Advanced Energy Systems

Interconnection: OptionalGrid-Connected or Stand-Alone


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DescriptionYosemite National Park is one of the mosttreasured environments in the UnitedStates and also the site of serious vehic-ular traffic congestion. The National ParkService is working to reduce traffic and

pollution in Yosemite by expanding theshuttle bus service and introducing elec-tric shuttle buses. This necessitates aninfrastructure of combined weather shel-ters and information boards at the newshuttle stops.

Funded by DOE FEMP, Kiss + Cathcart,Architects, is under contract to NREL todesign a prototypical bus shelter incorpo-rating BIPV panels. The park will begininstalling the first of 19 new shuttle stopsin the summer of 2000. The shelters that

are near existing electrical lines will sendthe power they generate into the utilitygrid system serving Yosemite; the moreremote shelters will have battery storagefor self-sufficient night lighting.

Special Design ConsiderationsThe design mandate for this project is tobalance a sense of the rustic historicalbuilding style of the Yosemite Valley withthe frankly technological appearance ofBIPV systems. The overall structure isa composite of heavy timber and steel

plates that serves two purposes: accom-modating heavy snow loads with mini-mum structural bulk and projecting anappearance that is rustic from a distancebut clearly modern in a close-up view.The structural timbers (unmilled logsfrom locally harvested cedar) are splitin half, and the space between them isused for steel connections, wiring, andmounting signage. The BIPV roof struc-ture is made of a single log cut into eightseparate boards.

A shallow (10) tilt was chosen for the PVroof. A latitude tilt of approximately 37would provide the maximum annual out-put in an unobstructed site; however, ashallower angle is better suited to

Yosemite because of the considerableshading that occurs at low sun angles inthe valleys, especially in winter. A steeperslope would also have made the shuttlestop much taller, significantly increasingstructural loading and demanding a heav-ier structure. This was determined to be

undesirable in terms of both appearanceand material use.

PV System ConfigurationFourteen semitransparent, 40-W thin-filmmodules make up the PV system for eachshelter. Power is fed to a single inverter.Some systems will be grid-connected andsome will be stand-alone with batteriesfor backup.

PV Module Mounting andAttachment DetailsThe PV roof of the shelter is not designedto be watertight like the roof of anenclosed building. Instead, it is designedto be waterproof so that water does notdrip through the roof in normal weather

conditions. Therefore, the PV modules areoverlapped (shingled) slightly along thecenter seam, and sheet metal gutters areinserted at the seam between the roughwood rafters and the modules.

design briefs:Yosemite Transit Shelter 3

Yosemite National Park


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36 design briefs: Sun Microsystems Clock Towe

Sun Microsystems Clock Tower

North-facing view ofthe clock tower at SunMicrosystems facility.

Location: Burlington, Massachusetts

Owner: Sun Microsystems

Date Completed: October 1998

Architect & Designer: HOK Architects and ASE Americas, Inc.

Structural Engineers: Whiting-Turner Contracting Co.

Electrical Engineers: Enertech EngineeringTradesman Required: Glaziers, electricians

Applicable Building Codes: Uniform Building Code

Applicable Electrical Codes: National Electric Code Section 620

PV Product: BIPV curtain wall

Size: 2.5 kWp

Projected System Electrical Output: 2.5 kWp



PV Cell Type: Polycrystalline silicon manufactured by ASE Americas, Inc.

PV Efficiency: 12.8%

PV Module Manufacturer: Pilkington Solar International

Inverter Number and Size: One 2.5 kWp inverter

Inverter Manufacturer and Model: Omnion Power Corp.



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DescriptionASE Americas recently provided the

design, PV panels, and electronic equip-ment needed to power an 85-ft high clocktower on Sun Microsystems' new 1 millionft2 campus in Burlington, Massachusetts.The architects who designed the buildingincluded both electrically active and elec-trically inactive glass panels on four sidesof the tower. The electrically active panelsincorporating PV modules were used onthe east and west sides. A diffuse lightpattern washes around the edges of thesolar cells in the inside of the tower tocreate a soft look in the interior. The clock

tower load is primarily a nighttime load.Energy from the PV array goes into thebuilding by day, and the clock towerdraws power at night from the building'selectrical grid. This could be the first useof dual-glazed, thermally insulated PVpanels in a U.S. building structure.

Special Design ConsiderationsThe PV panels were custom designed to

match the dimensions of the KawneerSeries 1600 mullion system used on thefour sides of the clock tower. They werefabricated as dual-glazed, thermallyinsulating panels with a glass-cell-glasslaminate as the outer surface and afrosted glass sheet as the inner surface.Some of the panels were required to wraparound the clock, so three different basicshapes were designed with round cuspscut out of the corners to match the curva-ture of the round, 7.5-ft-diameter clock.Two rectangular shapes were required so

the panels were vertically arranged tomatch the floor levels.

PV System ConfigurationThe PV modules are connected in seriesand feed electricity into an inverter thatconverts the 2.5 kW DC power to AC.

PV Module Mounting andAttachment Details

Eight electrically active panels were fulywired and interconnected through aninverter and transformer into the buildinwiring as a utility-interactive system.These systems are the simplest and moseconomical way to install a PV powersource. There are no batteries in this typof system, since the system draws powefrom the building's electrical grid.

design briefs: Sun Microsystems Clock Tower 3

Pilkington Solar Internationalsproject leader, John Goldsmith, isshown with the integrated curtainwall on the south and west facesof the clock tower.

East view of the clock tower shows BIPV installation.

ASE

Americas,

Inc./

PIX07042


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38 design briefs: State University of New York, Alban

State University of New York, Albany

Looking southeastat the Center forEnvironmentalSciences andTechnologyManagement

Location: Albany, New York

Owner: State University of New York, Albany

Date Completed: Summer 1996

Architect: Cannon Architects

Electrical Engineer: Cannon Architects

Solar Consultant: Solar Design Associates, Inc.Tradesmen Required: Beacon Sales Corporation, roofing contractors

Applicable building codes: New York State Building Code and ANSI Z97.1

Applicable electrical codes: National Electric Code

PV product: Kawneer 1600 PowerWall

Size: 15 kWp

Project System Electrical Output: 19,710 kWh / yr.


PV Weight: 1.93 lb / ft2


PV Cell Efficiency: 12%

PV Module Manufacturer: Solarex

Inverter Number and Size: AES 250 watt

Inverter Manufacturer and Model: Advanced Energy Systems Micro Inverter

Interconnection: Utility-Grid Connected


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DescriptionFor the new Center for EnvironmentalSciences and Technology Management(CESTM) at the State University of New

York in Albany, Cannon Architects devel-oped an energy-conscious design strat-

egy. This strategy included the integrationof solar electric systems into both thebuilding and the project site as landscapeelements. The building incorporates15 kWp of custom PV modules in building-integrated sunshades that support thePV modules while reducing cooling loadsand glare on the south facade. The PVmodules feature module-integratedinverters.

Special Design ConsiderationsThis system was the first of its kind in theUnited States to tie together more than2 kW of AC modules, and the first to usethe AC module platform for a sunshade.AC modules proved to be far more effec-tive than a typical single inverter, giventhe different light levels on the modulesover the course of a day.

PV System ConfigurationThere are two different system configura-tions in the CESTM solar system. Thesunshade portion consists of 59 pairs of

framed Solarex MSX 120 modules. Eachpair is connected to its own accessible ACmicro-inverter. The inverters are installedinside the building for ease of service. Thelandscape portion consists of 18 pairs ofSolarex MSX 240 modules. An AC micro-inverter is attached to the underside ofeach pair.

PV Mounting and AttachmentDetailsSolarex provided framed PV modules thatwere modified to incorporate the AES

micro-inverters. Most of the moduleswere mounted in an aluminum strut,creating a solar sunshade. The rest of themodules were mounted above ground,along a curved pathway at the mainapproach to the building. The buildingssunshades use standard extrusions fromthe Kawneer curtain wall system, theKawneer 1600 PowerWallTM. This customconfiguration provided structural supportto the modules.

design briefs: State University of New York, Albany 3

Close-up view of photovoltaic sunshade

GordonSchenck/PIX08464


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40 design briefs: Navajo Nation Outdoor Solar Classroo

Navajo Nation Outdoor Solar Classroom

Each new BIPV structure at the Seba Dalkai School will serve as an open-air classroomsupported by timber columns in a concrete foundation.

Location: Seba Dalkai, Navajo Reservation, Arizona

Owner: Seba Dalkai Boarding School

Scheduled Completion Date: Fall 1999

Architect: Kiss + Cathcart, Architects

Electrical Engineer: Energy Photovoltaics, Inc.

Solar Consultant: Kiss + Cathcart, ArchitectsTradesmen Required: Electricians, laborers

Applicable Building Codes: Standard building codes

Applicable Electrical Codes: National Electric Code

PV Product: Energy Photovoltaics EPV-40 modules

Size: 4.0 kWp




PV Type: Amorphous silicon

PV Efficiency: 6%

PV Module Manufacturer: Energy Photovoltaics, Inc.

Inverter Number and Size: Four 2.5 kW inverters

Inverter Manufacturer: Trace Engineering

Interonnection: Stand-Alone System


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DescriptionThe Seba Dalkai Boarding School, aBureau of Indian Affairs school on theNavajo Reservation in Arizona, is con-structing a new K-8 facility to be com-pleted in 2001. Funded by DOE FEMP, thisfacility will incorporate a BIPV systemcapable of producing approximately4.0 kW of electricity.

The school is currently housed in atraditional hogan and in a stone facilitybuilt in the 1930s. These will remain andbe juxtaposed with a new school facility.The photovoltaic component of thisproject will mediate between the old andthe new, and it will add a structure thatclearly expresses solar technology andBIPV principles. Funded by DOE FEMP,this structure will serve as an outdoor

classroom and as part of the schoolsHVAC circulation system. It will also be ahands-on laboratory for educating peopleabout BIPV systems and training them insystem installation.

Special Design ConsiderationsThe installation is designed to minimizethe cost of the support structure whileincorporating sustainable constructionmaterials. Within an enforced simplicity,the design attempts to establish a con-nection with Navajo building traditions.

PV System ConfigurationThe design includes two 25-ft x 25-ft,open-sided, timber-framed structures.Each one supports 2.88 kW of semitrans-parent PV modules, and each oneincludes two Trace 2.5-kW inverters plusbatteries for three days worth of energystorage. Each structure will function as anopen-air classroom.

PV Mounting and AttachmentDetailsThe PV modules are attached with alu-minum extrusions fixed with silicone tothe back of the glass (four per module).Each aluminum channel is 12 ft long. The

channels are supported on a grid of routimber beams, which in turn are sup-ported by timber columns on concretefoundations.

design briefs: Navajo Nation Outdoor Solar Classroom

The design attempts to establish a connection with Navajo building traditions.

02527275m


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42 design briefs: General Services Administration, Williams Buildin

General Services Administration, Williams Buildin

The nine-story Williams Building in Boston(at right in photo above) has a new BIPV roof(bottom, lower right photo) rather than aconventional one.

Location: 408 Atlantic Avenue, Boston, Massachusetts

Owner: U.S. General Services Administration

Date Completed: September 30, 1999

Project Developers: Enron Energy Services and U.S. General Services Administration

Electrical Engineer: PowerLight Co.

Solar Consultant: PowerLight Co.Tradesmen Required: Electricians and roofers

Applicable Building Codes: Standard building codes

Applicable Electrical Codes: National Electric Code, Boston Electric Interconnection Guidelines, and IEEESpecifications

PV Product: PowerLight, using ASE Americas, Inc., solar panels

System Size: 37 kW DC, 28 kW AC


Gross PV Surface Area: Approx. 3,800 ft2

PV Weight: 4 lb/ft2


PV Efficiency: 12%PV Module Manufacturer: ASE Americas, Inc.

Inverter Number and Size: 1 30 kVa

Inverter Manufacturer: Trace Engineering


PIX08465


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DescriptionIn this project, a regularly scheduled roofreplacement was upgraded to the installa-tion of a building-integrated photovoltaicroof. The BIPV roof is installed on theWilliams Building in downtown Boston.

The U.S. Coast Guard is the leading tenantof this 160,000-ft2 building, which sits onRowes Wharf at 408 Atlantic Avenue, nearthe citys financial district.

In addition to the new PV system for theroof, the building is also switching fromdistrict steam to on-site gas boilers. Two75-kW Teco-gen co-generation units arealso being added, as well as a high-efficiency chiller, more efficient lighting,and upgraded, more efficient motors.

Special Design ConsiderationsThe building is located on a wharf, so thedesign must take into account not onlythe water but also 140-mile-per-hour windconditions at the site.

After a site review, including a review ofthe wind conditions, the contractordecided to use a PowerLight RT photo-voltaic system. The RT system was chosenfor its cost-effectiveness when extremeroof penetrations are required (for exam-ple, with penthouses, skylights, and HVACframes).

PV System ConfigurationThis system produces 37 kWp DC and28 kW AC. Its 372 PV panels are con-nected in sets of 12. Each panel has a

maximum output of 100 watts.

PV Mounting and AttachmentDetailsA metal raceway, ballast, and anchoringsystem is used. It was also necessary toadd rigid insulation for thermal protectio

The PowerLight RT system is fastened tothe roof along its perimeter using epoxyembedded anchors set into the concretedeck. These use pitch pans and a racewafor moisture protection. The systemallows water to flow under thePowerGuard to existing roof drains. Itshould not be necessary to add newdrains.

A harness from the panels goes throughtwo conduits into attic space locatedabove the eighth floor. Part of the attic

needed additional metal decking.

design briefs: General Services Administration, Williams Building 4

PIX08473

PIX08471

PIX08472

PIX08470

View of the new BIPV roof onthe Williams Building, duringand after construction

Pavers are in foreground, PV array is in background onthe rooftop.

Wiring for the rooftop installation

Paul King, DOE Boston Regional Office FEMPliaison, surveys the installation work.


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44 design briefs: General Services Administration, Williams Buildin

The plan for the roof of the Williams Building included a rooftop BIPV system consisting of 372 solar panels.

02527263m

Co-funded by the DOE FEMP Renewable EnergyProgram, this BIPV application illustrates how thetechnology can be introduced into complex roof spaces.

JeffAnsley,P

owerLightCorporation/PIX08461

Shading from other buildings is not a problem at thissite, which is in urban Boston.


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design briefs:Academy of Further Education 4

Academy of Further Education

The Academy of Further Education under construction in Herne, Germany

Location: Herne, North Rhine-Westphalia, Germany

Owner: EMC, Ministry of Interiors of North Rhine-Westphalia, City of Herne

Date Completed: May 1999

Architect & Designer: Jourda et Perraudin Architects, HHS Architects

Structural Engineers: Schleich, Bergermann and Partner

Electrical Engineers: HL-TechnikTradesmen Required: Glaziers, electricians

PV Product: BIPV roof

Size: 1 MWp


Gross PV Surface Area: 10,000 m2

PV Weight: 130 kg per each 3.2 m2 module

PV Cell Type: Polycrystalline and monocrystalline silicon

PV Efficiency: 12.8% to 16%

PV Module Manufacturer: Pilkington Solar International, Cologne

Inverter Number and Size: 600, 1.5 kW

Inverter Manufacturer and Model: SMA, Kassel



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DescriptionAs part of the International ConstructionExhibition, Emscher Park, the site of a for-mer coal mine in Herne, Germany, is beingused for a new purpose. A comprehensiveurban development plan is providing the

district of Sodingen with a new center-piece: the Academy of Further Education,Ministry of Interior, North Rhine-Westphalia.

The large glass hall incorporates not onlythe Academy but also a hotel, library, andadministrative municipal offices. Theglass hall is multifunctional. It protectsthe interior from harsh weather and usessolar energy both actively and passivelyby producing heat as well as electricpower.

Special Design ConsiderationsApproximately 3,180 multifunctional roofand facade elements are the core of thesolar power plant. With a total area of10,000 square meters, most of the roofand the southwest facade is covered byphotovoltaics, making this system thelargest building-integrated PV powerplant in the world. It produces approxi-mately 750,000 kWh of electric powerper year. This is enough to supply morethan 200 private residences. About

200,000 kWh is used directly by theAcademy building, and the remaining550,000 kWh is fed into the public powergrid in Herne.

PV System ConfigurationThe Optisol photovoltaic elements wereproduced by Pilkington Solar at a site inGermany. The PV system consists of solarcells embedded between glass panes.Daylighting needs were taken intoaccount in designing the roof- and facade-integrated system. The PV modules have

areas of 2.5 to 3.2 square meters and anoutput of 192 to 416 peak watts each. Thismakes them larger and more powerfulthan most conventional solar modules.

Direct-current electricity is converted to230 V alternating current by means ofa modular inverter. This is made up ofroughly 600 decentralized string invertersand allows optimal use of the incidentsolar radiation.

Mounting and AttachmentDetailsThe building-integrated photovoltaicpanels are set into aluminum mullionslike skylights. The rooftop panels arepositioned at an angle to capture as muchof the incident sunlight as possible.

46 design briefs:Academy of Further Educatio

An inside view of the Academy building as construction progressed

This photo shows how the PV panels are angled to capture the sunlightshining on the roof.


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design briefs:Academy of Further Education 4

Rooftop view shows placement of insulation and PV panels.


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48 design briefs: Discovery Science Cente

Discovery Science Center

Architects renderinof the DiscoveryScience Center Cubein Santa Ana,California

Location: Santa Ana, California

Scheduled Completion Date: November 1999

Architect & Designer: Arquitectonica for the cube, Solar Design Associates for the PV system

Structural Engineers: Advanced Structures, Inc.

Electrical Engineers: Solar Design Associates, Inc.

Tradesmen Required: ElectriciansApplicable Building Codes: Building Administrators Code Administrators International (BOCA)


PV Product: Thin-film photovoltaic system

Size: 20 kWp



PV Weight: 3 lb/ ft2

PV Cell Type: Thin-film technology

PV Efficiency (%): 5.1 %

PV Module Manufacturer: BP Solarex

Inverter Number and Size: 4

Inverter Manufacturer and Model: Omnion 2400, Model 5015

Interconnection: Utility Grid-Connected

SolarDesignAssociates,

Inc./

02527271


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DescriptionThis solar electric system, located inSanta Ana, California, boasts one of theworld's largest building-integrated thin-film applications to date. The PV-coveredsurface of the cube is tilted at 50 for

maximum visual impact and optimal solarharvest. BP Solarex's Millennia modulescover the entire 4,334-ft2 top of the cubeThe thin-film modules are treated as an

architectural glazing element, replacingwhat would have been a glass canopy.They produce up to 20 kW of DC electricityat mid-day and 30,000 kWh of electricalenergy per year, which is enough to runfour typical homes.

The solar energy system is connectedto the Discovery Science Center's mainutility line. When the solar system pro-duces energy, it feeds the energy to the

Science Center, displacing conventionalutility power. When the solar systemproduces more electricity than theScience Center needs, the excess elec-tricity is "exported" to the utility, therebeffectively spinning the electric meter

backwards.

design briefs: Discovery Science Center 4

The view from inside the cube

SolarDesignAss

ociates,

Inc./

02527277m


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50 design briefs: Solar Sunflowe

Solar Sunflowers

These Solar Sunflowerstrack the sun to produceelectricity.

Location: Napa, California

Date Completed: N/A

Architect & Designer: Solar Design Associates, Inc.

Structural Engineers: Solar Design Associates, Inc.

Electrical Engineers: Solar Design Associates, Inc.

Tradesmen Required: ElectriciansApplicable Building Codes: Building Officials Code Administrators International (BOCA)


PV Product: BP Solarex

Size: 36,000 Wp

Projected System Electrical Output: N/A


PV Weight: 3.4 lb/ ft2

PV Cell Type: Polycrystalline

PV Efficiency: 11.1%

PV Module Manufacturer: BP Solarex

Inverter Number and Size: 6

Inverter Manufacturer and Model: Omnion Series 2400, Model 6018


PIX08468


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DescriptionNestled atop a hillside in NorthernCalifornia, 36 Solar Electric Sunflowersrepresent an elegant combination of artand technology. The clients requested anunconventional and artistic installation.

They got just that.

Just like a sunflower, the Solar ElectricSunflowers look and act like nature's ownvariety. Making use of a two-axis trackingsystem, the sunflowers wake up to followthe sun's path throughout the day,enabling the system to produce enough

energy for eight to ten homes.

design briefs: Solar Sunflowers

Solar electric sunflowers resemble natures own.

PIX08467


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52 design briefs: Ijsselstein Row House

Ijsselstein Row Houses

Fourteen planned new row-house units in the Netherlands demonstrate the aesthetic use ofbuilding-integrated photovoltaics: front (above) and back views.

Location: Ijsselstein Zenderpark, Ijsselstein, The Netherlands

Date Completed: Scheduled for completion in late 2000

Architect & Designer: Han Van Zwieten, Van Straalen Architecten, co-designer; Gregory Kiss, Kiss + CathcaArchitects, co-designer

Structural Engineers: N/A

Electrical Engineers: N/A

Tradesmen Required: Building tradesmen

Applicable Building Codes: Dutch Building Code

Applicable Electrical Codes: Dutch Electrical Code

PV Product: Standard-size BIPV glass laminate panels

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