Solar Air Heating Roofing and Siding for Government and ... ... ¢â‚¬â€œ Better performing roof (longer life,

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  • American Solar, Inc. www.americansolar.com (703) 425-0923 1

    Solar Air Heating Roofing and Siding for Government and Commercial Buildings

    Prepared by

    John Archibald American Solar, Inc.

    ASHRAE Roanoke 4/9/13

  • American Solar, Inc. www.americansolar.com (703) 425-0923 2

    “Everybody knows”…..

  • American Solar, Inc. www.americansolar.com (703) 425-0923 3

    It turns out……

    HEAT is the largest energy need across all US

    buildings

    “Everybody knows”… air conditioning drives electricity to the highest energy use in buildings

    So, Why Solar Heat, …WHEN WE NEED COOLING?

  • American Solar, Inc. www.americansolar.com (703) 425-0923 4

    Space HeatingCooling / Refrig

    Lighting

    Water Heating

    Process Heat

    Equipment

    Others

    Clothes Drying Boilers

    NON-HEATING LOADS

    HEATING LOADS

    ENERGY USES IN RESIDENTIAL, COMMERCIAL, AND INDUSTRIAL BUILDINGS

    THE LARGEST NEED FOR ENERGY IN THE U.S. IS FOR HEATING

    Portions of all energy used in buildings and facilities, Source data: US Energy Information Administration

    75°F

    140°F

    120°F

    90+°F

  • American Solar, Inc. www.americansolar.com (703) 425-0923 5

    Which Solar Energy Systems Can Meet the Heating Needs?

    • Specialized Add-on Solar Panels – SolarWall™ -- $/sqft – Solar Air Heating Panels -- $$/sqft – Solar Hot Water Panels & Tubes –

    • ¢¢/sqft (lo temp) • $$/sqft (hi temp)

    – Solar Electric (PV) – PV Panels, Shingles, Tiles -- $$$$/sqft

    • Conventional Metal Roofs and Walls – – $/sqft (existing, re-roof, or

    new construction)

  • American Solar, Inc. www.americansolar.com (703) 425-0923 6

    Basic types of solar roofing • Solar electric systems (PV)-

    – most expensive, least productive, least economical, electrical connection regs, holes in the roof

    • Solar water heating, – Less expensive, more productive, economical,

    complicated plumbing, risk of freeze damage and leaks, liquid in the roof

    • Solar air heating systems – Least expensive, productive, pays for re-roof in few

    years, least complicated, built as conventional, weather tight metal roofs, with no holes.

    – Simply pull heated air off the backside of a hot conventional metal roofing panel

    – Deliver heated air to the building for many uses, • heat air, heat water, heat equipment, etc.

  • American Solar, Inc. www.americansolar.com (703) 425-0923 7

  • American Solar, Inc. www.americansolar.com (703) 425-0923 8

    Solar Air Heating Roofs Technology Description

    • A Conventional Metal Roof • Sun light heats roof panels, OAT + 80F • Air under metal roof panel heats, OAT + 40-

    80F • Simple fan and ductwork delivers heated air

    for uses in the building – Space heat, water heat, outside air preheat,

    equipment heat, process heat (drying, etc.) • Sloped Metal Roof gives better drainage

    and longer life than flat membrane/BUR roof • Cooler in summer from radiant barrier &

    insulation – Equal to a “Cool Roof” • Removal of old roof is not required

    – Keeps building weather tight during install – Reduces tear-off /transport /disposal costs

  • American Solar, Inc. www.americansolar.com (703) 425-0923 9

    • Labs with high outside air are most energy inefficient and expensive from heating costs

    • Conventional metal re-roof over existing standing seam roof

    • Ducts and fans added to pull solar heated air to building outside air intakes

    How Solar Air Heating Roofs Are Installed: FDA Lab, Standing Seam Metal Over Metal

    • 10 lab buildings with 100% conditioned outside air

    • Roofing contractor installs roof over sub-purlins and new solar siding

    • Solar or HVAC contractor installs ducts, fans, controls

  • American Solar, Inc. www.americansolar.com (703) 425-0923 10

    Laboratory Outside Air Preheat Solar roofing and siding preheating

    outside air for 100% outside air buildings

    0

    10

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    5: 30

    6: 05

    6: 41

    7: 17

    7: 53

    8: 28

    9: 04

    9: 40

    10 :1

    5 10

    :5 1

    11 :2

    7 12

    :0 3

    12 :3

    8 13

    :1 4

    13 :5

    0 14

    :2 5

    15 :0

    1 15

    :3 7

    16 :1

    3 16

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    17 :2

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    :0 0

    18 :3

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    :1 1

    Hour of Day

    Te m

    pe ra

    tu re

    (F )

    0

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    So la

    r I ns

    ol at

    io n

    (W /m

    ^2 )

    or F

    an P

    ow er

    (W )

    T, Solar Roof (F)

    T, Outdoor (F)

    T, Attic (F)

    P, Fan Power (W)

    Solar Insolation (W/m^2)

    T, Attic

    T, Solar

    T, Outdoor

    P, Fan Solar Insolation

    Monitored 11/19/08

  • American Solar, Inc. www.americansolar.com (703) 425-0923 11

    •High temperatures can be achieved even with light colored metal roofing • Heat can be used for space heat, water heat, heat pump preheat, “Air- Radiant” floor, air conditioner re-heat, dehumidification , drying, paint booth preheat, etc.

    Summer solar air temperatures

    Solar Roof Air Temperatures Hill AFB, Utah

    0 20 40 60 80

    100 120 140 160 180

    00 :0

    0: 00

    07 /1

    0/ 09

    12 :0

    0: 00

    07 /1

    0/ 09

    23 :0

    0: 00

    07 /1

    0/ 09

    11 :0

    0: 00

    07 /1

    1/ 09

    23 :0

    0: 00

    07 /1

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    11 :0

    0: 00

    07 /1

    2/ 09

    23 :0

    0: 00

    07 /1

    2/ 09

    Te m

    p, D

    eg F

    Solar Roof Air Temp Outdoor Air Temp Indoor Space Temp

  • American Solar, Inc. www.americansolar.com (703) 425-0923 12

    Solar Air-Heating Metal Re-Roof Over Built Up Roof

    Gaffney Fitness Facility Fort Meade, MD

    •Solar re-roof funded by •DOD Environmental Security Technology Certification Program (ESTCP)

  • American Solar, Inc. www.americansolar.com (703) 425-0923 13

    Technical Approach • Solar re-roof for

    – Better roof – Solar heat air & water

    • Solar Air Heating Metal Re- roof

    – Sloped gym roof and – Sloped re-roof over portion of flat

    roof • Warm solar air to preheat

    outside air for gym • Solar air heats water

    – via copper coil heat exchanger – for showers/sinks

  • American Solar, Inc. www.americansolar.com (703) 425-0923 14

    Technical Approach • Solar roof installed over gym roof

    and projects over a portion of flat roof • Solar air is sent to outside air intake to

    preheat outside air during winter • Solar air preheats cold water under new

    sloped roof section – Water preheat before entering hot water heater – Exhaust solar air directed to building in winter

  • American Solar, Inc. www.americansolar.com (703) 425-0923 15

    Outdoor Air Preheat Performance • Solar air delivered to air handler outdoor air intake • Solar air blown at air intake, no physical connection or

    flow/pressure balancing required at intake. • ON-OFF control input from BAS when gym calls for heat • Differential Temperature Controller turns solar fans ON-

    OFF based on delta Solar Air T > OAT

  • American Solar, Inc. www.americansolar.com (703) 425-0923 16

    • Matches Largest Energy Needs, for year round solar delivery – 68-72F Space (air) Heat, 40-120F Water Preheat, 0-50F

    Outdoor Air Preheat • High temperature water not needed for low temperature preheat needs • Easier to collect and move air

    – Minimal air circuit enclosure unlike tight plumbing circuit – No fluid leaks to worry about inside or outside the building envelope – No freeze protection, antifreeze, minimal plumbing system integration – Air-to-water heat transfer in a conditioned space

    • Simple, - Fan, thermostat, (Optional heat exchanger and pump) • Lower Cost,

    – $5-25/sqft roof (roof $ credit) vs. $40-100/sqft hot water panels • More Energy,

    – 15-30% eff. heat recovery from entire roof vs 30-80% from 80sqft panels • Downside: -Bigger ducts, more insulation that water based system

    “Everybody knows”… hot water transfers more heat than hot air So, why Solar Air Heat for water heating?

  • American Solar, Inc. www.americansolar.com (703) 425-0923 17

    Water Heating with Solar Heating Roofs

    • Water heating panels – Mounted on and through the roof – Sun-panel-glycol-copper-water

    • Water in the roof – Water tubes below metal panel roof – Glycol for freeze protecti