gsa presentation
TRANSCRIPT
A durable integrated systemA durable integrated systemfor PV installations on existing and new roofsfor PV installations on existing and new roofs
Presentation ContentBasics of metal roofing
Basics of photovoltaics (PV)
Synergy of solar and metal roofing
The most cost-compelling choice
Retrofitting opportunities
Look at the roof and PV system together as a single asset.
Then assess the total cost of ownership over the total life of the asset
Basics of Metal Roofing
Metal Roof BenefitsSustainable
Reflective, emissive
More energy efficient
LEED® friendly
Made from recycled materials
100% recyclable
Aesthetically beautiful
Metal is Durable
1200-1450
Metal OffersDesign Flexibility
Metal ProvidesLong Service Life
Coatings for SteelGalvanized Zinc
Aluminized™ Aluminum
Galvalume® Aluminum + Zinc
Metal is Sustainable
SustainabilityStrength, durability, longevity• Resists harsh weather, wind, and fire with minimal or no
maintenance• Impervious to UV degradation• Galvalume® steel standing-seam roof has 40- to 60-year
service life, depending upon environmental severity
25% recycled content, 100% recyclable • At a 93.3% recycle rate, steel is the most highly recycled
construction material available.*
Energy efficiency• Meets ENERGY STAR requirements with high reflectance
Lower life-cycle cost than other roof types*Source: Steel Recycling Institute, 2008
35-year-old Galvalume® steel roofNew Orleans, LA
28-year-old roof Ergoldsbach, GermanyThis roof, which is about to be retrofittedwith a PV array, is estimated to have a remaining service life of 30 years or more.
Metal Roof Benefits
Features• Sustainable• Reflective, emissive• More energy efficient• LEED® friendly• Made from recycled
materials• 100% recyclable• Aesthetically beautiful
Environmental Benefits• Reduce landfill waste• Reduce carbon footprint• Accommodate solar
technologies• Retain properties• Reduce roof maintenance• Provide long service life
Basics of Photovoltaics
Solar Power SystemsSystem types• thin film
- amorphous silicon (a-Si)- cadmium telluride (CdTe)- copper indium selenide (CIS)- copper indium/
gallium diselenide (CIGS)- light-absorbing dyes- dye-sensitized solar cells (DSSC)
Solar Power SystemsSystem typesmono- and poly-crystallineMetal roofs accommodate necessary attachment hardware.Eligible for Federal solar-energy tax creditsOther benefits beyond solar energy
Issues: PV Attachment to Conventional RoofRequires waterproofingat solar array attachmentsRequires dismantling• Remove old• Install new• Reinstall PV
No holes!
PV Attachment to Metal Roof
Metal Roof with PVNo holes = no leaks• Thin-film and crystalline systems
No costly reinstallationLonger service life• 24%–43% savings over installing PV over conventional roofs
Considerations for PV over conventional roofs must include long-term roof-replacement cost
Thin Film Laminated PVThin-film amorphous silicon thickness =less than 1 micron
Stainless steels substrate = 5 mil
Protective coating = ETFE film
Average weight = .7 lbs/sq ft
Thin-film PV is flexible, durable, and fits into standing seam roofs
Thin-film applications are aesthetically pleasing, casting no shadows or causing any glare.
Crystalline Si PV Panels
Popular for vast expanses of commercial, industrial, office, and retail rooftops (±700,000,000 sf annually)
Top Solar StatesCumulative as of EOY 2008
0 100 200 300 400 500 600
North Carolina
Oregon
Connecticut
Hawaii
New York
Arizona
Nevada
Colorado
New Jersey
California
Source: IREC
Prices are coming DOWN!Average wholesale and factory gate pricing (2009)
$0.00
$0.50
$1.00
$1.50
$2.00
$2.50
$3.00
$3.50
$4.00
Jan Feb Mar Apr May Jun Jul Aug Sep
WholesaleFactory Gate
What is the service life of PV?
The warranted life = 25 years…but the service life ≈ 30 years.
Penetration of Conventional Roof System
Options for mountingto conventional roof types:
Option• Penetrations
• Ballast
• Adhesion
• Aerodynamic• Unique Collectors
Problem• Cost• Risk of leakage• Warranty violations• Limited to new
construction• Added to dead load• Limited to new or reroof• Limited to thin-film
alternatives• Cost• Cost
More than 10,000 points of attachment
Conventional Roof TypeRacking components .65Anchorage/waterproofing .20System assembly (labor) .20
Mounting system cost 1.05
Total system cost 5.50Total system cost 6.40
Mounting Cost Summary(dollars per Watt)
Standing Seam Metal RoofSeam clamps and interface .10System assembly (labor) .10
Mounting system cost .20
Total system cost 4.65Total system cost 5.55
13% of SYSTEM COST13% of SYSTEM COST15.5% of SYSTEM COST15.5% of SYSTEM COST
Source: www.energycodes.gov
Map of DOE Proposed Climate ZonesAdopted by ASHRAE and IECC
AGED BRONZE COLORED ROOF:
T Sun = 174º FT Shade = 118º FΔT Sun to Shade = 56º F
(ambient = 81º F)
A convective air plenum ensures even A convective air plenum ensures even cooler temperatures.cooler temperatures.
Conventional Roof Types: Service LifeService life of PV = 30 years ±
Service life of BUR = 19.8 years
Service life of APP = 16.1 years
Service life of SBS = 17.7 years
(The service life of other commercial roof types = 12–20 years.)
Source: Carl Cash Survey, Simpson, Gumpertz & Heger, 2005
Conventional Roof Types: Service LifeService life of PV = 30 years ±
Service life of BUR = 19.8 years
Service life of APP = 16.1 years
Service life of SBS = 17.7 years
(The service life of other commercial roof types = 12–20 years.)
Source: Carl Cash Survey, Simpson, Gumpertz & Heger, 2005
Roof Service Life
Roof Service Life
DEFICITDEFICIT
= 10-18 years
= 10-18 years
So when roof life expires…So when roof life expires…dismantle the PV array…dismantle the PV array…tear the roof off…tear the roof off…
throw it away…throw it away…reroof, and then…reroof, and then…reassemble the PV array.reassemble the PV array.
SSMR: Service LifeService life of PV = 30 years
Service life of SSMR = 50 years
No roof replacement—the roof outlives the PV system!
SSMR: Service LifeService life of PV = 30 years
Service life of SSMR = 50 years
No roof replacement—the roof outlives the PV system!
Roof Service Life
Roof Service Life
SURPLUS
SURPLUS
= 10–18 years
= 10–18 years
Coated Steel SSMRInitial cost of roof $ 7Initial cost of PV $56Initial cost Subtotal $63
Total 30-year cost $63(20-year roof life surplus)
Economic Impact of Roof Replacement (assuming new construction)
15-Year TPO Single-PlyInitial cost of roof $ 4Initial cost of PV $64Initial cost Subtotal $68Yr 15 PV removal $ 4Yr 15 Roof Recover $ 3Yr 15 PV re-assy $ 9Total 30-year cost $84
(0 roof life)
Coated Steel SSMRInitial cost of roof $ 7Initial cost of PV $56Initial cost Subtotal $63
Total 30-year cost $63(20-year roof life surplus)
Economic Impact of Roof Replacement (assuming new construction)
15-Year TPO Single-PlyInitial cost of roof $ 4Initial cost of PV $64Initial cost Subtotal $68Yr 15 PV removal $ 4Yr 15 Roof Recover $ 3Yr 15 PV re-assy $ 9Total 30-year cost $84
(0 roof life)A savings of 25%
A savings of 25%
over the life
of the system.
over the life
of the system.
Method: Direct Mount—seam clamp and interfaceMethod: Direct Mount—seam clamp and interfaceMounting system cost: $0.087/wattMounting system cost: $0.087/watt
Look at the roof and PV system together as a single asset.
Then assess the total cost of ownership over the total life of the asset
Retrofit Solutionsfor Existing Buildings
Solutions for any reason or purpose
Solutions for any reason or purpose
BeforeBefore
AfterAfter
Reroofing SolutionsMetal over existing flat roofs• Replace petroleum-based roofing products • Add slope to a flat or nearly flat roof• Enhance aesthetics, curb appeal
Retrofit
Economical for new construction
Flat Roof Applications
After
Before During
Before
Reroofing SolutionsMetal over existing flat roofs• Replace petroleum-based roofing products • Add slope to a flat or nearly flat roof• Enhance aesthetics, curb appeal
Metal over existing sloped roofs • Replace petroleum-based roofing products• Upgrade wind-uplift and energy requirements• Restore aged metal roofs
Sloped Roof Solutions
Reroofing SolutionsMetal over existing flat roofs• Replace petroleum-based roofing products • Add slope to a flat or nearly flat roof• Enhance aesthetics, curb appeal
Metal over existing sloped roofs • Replace petroleum-based roofing products• Upgrade wind-uplift and energy requirements• Restore aged metal roofs
Metal can alter roof geometry to improve drainage issues and reorient slope for optimal solar gain
Problematic RoofsDuring Near Complete
During After
Energy-Saving OpportunitiesSignificant savings, minimal investment
Energy savings from• adding insulation
Insulated Applications
Existing roofand purlins
New metal roof
New subpurlins
New insulation
Energy-Saving OpportunitiesSignificant savings, minimal investment
Energy savings from• adding insulation• radiant barrier
installation• convective ventilation
Less30%–45% heat gain
Natural Convective Ventilation (ASV)New metal roof
Existing roof
Hot air out
Ambient air in
Air heats upand moves upward
by convection
Radiant heat Less heat loss
Building heat
Energy-Saving OpportunitiesSignificant savings, minimal investment
Energy savings from• adding insulation• radiant barrier
installation• convective ventilation• renewable solar
- thermal heat recovery- solar water heating
Solar Thermal Heat Recovery
Ambient air inHeated air distributed to HVAC system with
solar powered fan
Air heats upand moves upward
by convection
New metal roof
Existing roof
Winter –closed ridge
Solar Thermal Water Heating
New metal roofOptional insulation
Vented eave
Circulated fluidin flexible tubing heats up
Reflective radiant barrier and insulation
Retrofit Makes $enseEnergy Saving Solutions
SummaryThe ideal platform for PV installation
A sustainable product
A strong synergy between PV and metal roofing
Significant cost savings possible over life of metal roof
Retrofit opportunities allow for PV benefits on existing buildings