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Metal Roofing and Solar
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Metal Roofing and Solar

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Metal Roofing and Solar

Metal Roofing and Solar

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  • 1. A durable integrated system for PV installations on existing and new roofs
  • 2. Presentation Content Basics of metal roofing Basics of photovoltaics (PV) Synergy of solar and metal roofing The most cost-compelling choice Retrofitting opportunities
  • 3. 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
  • 4. Basics of Metal Roofing
  • 5. Metal Roof Benefits Sustainable Reflective, emissive More energy efficient LEED® friendly Made from recycled materials 100% recyclable Aesthetically beautiful
  • 6. Metal is Durable
  • 7. 1200-1450
  • 8. Metal Offers Design Flexibility
  • 9. Metal Provides Long Service Life
  • 10. Coatings for Steel Galvanized Zinc Aluminized™ Aluminum Galvalume® Aluminum + Zinc
  • 11. Metal is Sustainable
  • 12. Sustainability Strength, 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
  • 13. 35-year-old Galvalume® steel roof New Orleans, LA
  • 14. 28-year-old roof Ergoldsbach, Germany This roof, which is about to be retrofitted with a PV array, is estimated to have a remaining service life of 30 years or more.
  • 15. 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
  • 16. Basics of Photovoltaics
  • 17. Solar Power Systems System 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)
  • 18. Solar Power Systems System types mono- and poly-crystalline Metal roofs accommodate necessary attachment hardware. Eligible for Federal solar-energy tax credits Other benefits beyond solar energy
  • 19. Issues: PV Attachment to Conventional Roof Requires waterproofing at solar array attachments Requires dismantling • Remove old • Install new • Reinstall PV
  • 20. No holes! PV Attachment to Metal Roof
  • 21. Metal Roof with PV No holes = no leaks • Thin-film and crystalline systems No costly reinstallation Longer service life • 24%–43% savings over installing PV over conventional roofs Considerations for PV over conventional roofs must include long-term roof-replacement cost
  • 22. Thin Film Laminated PV Thin-film amorphous silicon thickness = less than 1 micron Stainless steels substrate = 5 mil Protective coating = ETFE film Average weight = .7 lbs/sq ft
  • 23. Thin-film PV is flexible, durable, and fits into standing seam roofs
  • 24. Thin-film applications are aesthetically pleasing, casting no shadows or causing any glare.
  • 25. Crystalline Si PV Panels
  • 26. Popular for vast expanses of commercial, industrial, office, and retail rooftops (±700,000,000 sf annually)
  • 27. Top Solar States Cumulative 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
  • 28. 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 Wholesale Factory Gate
  • 29. What is the service life of PV? The warranted life = 25 years… but the service life ≈ 30 years.
  • 30. Penetration of Conventional Roof System
  • 31. Options for mounting to 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
  • 32. More than 10,000 points of attachment
  • 33. Conventional Roof Type Racking components .65 Anchorage/waterproofing .20 System assembly (labor) .20 Mounting system cost 1.05 Total system cost 5.50 Total system cost 6.40 Mounting Cost Summary(dollars per Watt) Standing Seam Metal Roof Seam clamps and interface .10 System assembly (labor) .10 Mounting system cost .20 Total system cost 4.65 Total system cost 5.55 13% of SYSTEM COST 15.5% of SYSTEM COST
  • 34. Source: www.energycodes.gov Map of DOE Proposed Climate Zones Adopted by ASHRAE and IECC
  • 35. AGED BRONZE COLORED ROOF: T Sun = 174º F T Shade = 118º F ΔT Sun to Shade = 56º F (ambient = 81º F)
  • 36. A convective air plenum ensures even cooler temperatures.
  • 37. Conventional Roof Types: Service Life Service 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
  • 38. Conventional Roof Types: Service Life Service 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
  • 39. So when roof life expires… dismantle the PV array… tear the roof off…
  • 40. throw it away… reroof, and then… reassemble the PV array.
  • 41. SSMR: Service Life Service life of PV = 30 years Service life of SSMR = 50 years No roof replacement—the roof outlives the PV system!
  • 42. SSMR: Service Life Service life of PV = 30 years Service life of SSMR = 50 years No roof replacement—the roof outlives the PV system!
  • 43. Coated Steel SSMR Initial cost of roof $ 7 Initial cost of PV $56 Initial 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-Ply Initial cost of roof $ 4 Initial cost of PV $64 Initial cost Subtotal $68 Yr 15 PV removal $ 4 Yr 15 Roof Recover $ 3 Yr 15 PV re-assy $ 9 Total 30-year cost $84 (0 roof life)
  • 44. Coated Steel SSMR Initial cost of roof $ 7 Initial cost of PV $56 Initial 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-Ply Initial cost of roof $ 4 Initial cost of PV $64 Initial cost Subtotal $68 Yr 15 PV removal $ 4 Yr 15 Roof Recover $ 3 Yr 15 PV re-assy $ 9 Total 30-year cost $84 (0 roof life)
  • 45. Method: Direct Mount—seam clamp and interface Mounting system cost: $0.087/watt
  • 46. 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
  • 47. Retrofit Solutions for Existing Buildings
  • 48. Solutions for any reason or purpose
  • 49. Solutions for any reason or purpose
  • 50. Before After
  • 51. Reroofing Solutions Metal over existing flat roofs • Replace petroleum-based roofing products • Add slope to a flat or nearly flat roof • Enhance aesthetics, curb appeal
  • 52. Retrofit Economical for new construction Flat Roof Applications After Before During Before
  • 53. Reroofing Solutions Metal 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
  • 54. Sloped Roof Solutions
  • 55. Reroofing Solutions Metal 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
  • 56. Problematic Roofs During Near Complete During After
  • 57. Energy-Saving Opportunities Significant savings, minimal investment Energy savings from • adding insulation
  • 58. Insulated Applications Existing roof and purlins New metal roof New subpurlins New insulation
  • 59. Energy-Saving Opportunities Significant savings, minimal investment Energy savings from • adding insulation • radiant barrier installation • convective ventilation
  • 60. Natural Convective Ventilation (ASV) New metal roof Existing roof Hot air out Ambient air in Air heats up and moves upward by convection
  • 61. Energy-Saving Opportunities Significant savings, minimal investment Energy savings from • adding insulation • radiant barrier installation • convective ventilation • renewable solar - thermal heat recovery - solar water heating
  • 62. Solar Thermal Heat Recovery Ambient air inHeated air distributed to HVAC system with solar powered fan Air heats up and moves upward by convection New metal roof Existing roof Winter –closed ridge
  • 63. Solar Thermal Water Heating New metal roof Optional insulation Vented eave Circulated fluid in flexible tubing heats up Reflective radiant barrier and insulation
  • 64. Retrofit Makes $ense Energy Saving Solutions
  • 65. Summary The 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

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