Roofing Systems in the 21 st Century; DOEs Research Program to - - PowerPoint PPT Presentation

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Roofing Systems in the 21 st Century; DOEs Research Program to - - PowerPoint PPT Presentation

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Roofing Systems in the 21 st Century; DOEs Research Program to Reduce their Energy Impact Andre Desjarlais Oak Ridge N ational Laboratory 24 May 2012 Managed by UT-Battelle for the U.S. Department of Energy Buildings energy use is large

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Managed by UT-Battelle for the U.S. Department of Energy

Roofing Systems in the 21st Century; DOE’s Research Program to Reduce their Energy Impact

Andre Desjarlais Oak Ridge National Laboratory 24 May 2012

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2 Managed by UT-Battelle for the U.S. Department of Energy

Buildings energy use is large and growing

Industry 377 MMTC (25%) Buildings 658 MMTC (43%)

34% of Natural Gas Directly (55% Incl. Gen) 73% of U.S. Electricity 40% of U.S. Primary Energy Consumption (39% of U.S. Carbon Emissions)

Source: 2007 Buildings Energy Data Book. Tables 1.1.3, 1.2.3, 1.3.3

500 1000 1500 2000 2500 3000

1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 Sales (Billion kWh) Buildings Industry Source: EIA Annual Energy Review, Table 8.9, June 2007

Buildings Drive Electricity Supply Investment

5 10 15 20 25 30 35 40 45 1980 1985 1990 1995 2000 2005 Year Quads

Industrial Transportation Buildings Total

Buildings Energy Use Growing Fastest

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3 Managed by UT-Battelle for the U.S. Department of Energy

Roofs and attics project is a highly leveraged public-private partnership

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  • Field study on attic

performance

  • Hot climate roof and attic

design guidelines

  • Advances in cool roof

technologies

  • Impacts of radiant barrier

systems

  • PV roof integration

FY11 FY11-12 k 12 key tasks and mil ey tasks and milestones estones

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NET NET facility acility use used d to to evalua valuate te attic ttic systems systems

2 3 4 5 6 1 7

Non breathable Low perm Adhered 15-lb felt

Sealed 1/300 1/300 ASV 1/300 1/300 1/150

Perm membrane Radiant barrier

Fascia

Cool shingles Low density foam, 15-lb felt 15-lb felt

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6 Managed by UT-Battelle for the U.S. Department of Energy

  • In each bay
  • 8 temperature sensors, 6 Rh sensors, 3 heat flux sensors
  • Total 17 sensors per bay + 7 for air temperature and Rh
  • 3 attic pressure and 3 sensors for insulation = 30 sensors per bay

Temp Roof surface, underlayment, deck Rh Underlayment, deck, rafters, Insulation Heat flux Roof deck, attic floor Temp Air Pressure Air

Instr Instrumenta umentation plan tion plan

Single Bay

T1

T2,RH1 (under felt) T3,RH2 (sheathing underside) T9,RH7 (joist) P1 T11

T5,RH4 T12 T16 HFT3

T13 P2 T14

HFT1

T10,RH8 P3 T15 HFT2 T6 T7,RH5 (under felt) T8,RH6 (sheathing underside) T4,R3 (joist)

South

These sensors are all in the Same vertical plane, both sides

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7 Managed by UT-Battelle for the U.S. Department of Energy

CONFIDENTIAL

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8 Managed by UT-Battelle for the U.S. Department of Energy

  • 5

5 10 15 20 25 30 35 40 45 50 55 20 40 60 80 100 120 140 160 24 48 72

Attic Air Temperature (C˚)

Dashed Lines

South Roof Deck Heat Flux (W/m2)

Solid Lines

Lower Attic Air Temperature (20 C˚) 71% Lower Flux Through Roof Deck

Sealed attic (RUS-22) has lowest roof deck heat flux

Attic 1 Conventional control attic Attic 2 Low density foam sealed Attic 5 Low perm underlayment with ASV

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16 17 18 19 20 21 22 23 24 25 26 27 4 8 12 16 20 24 28 32

24 48 72 Ceiling Temperature (C˚)

Dashed Lines

Ceiling Heat Flux (W/m2)

Solid Lines

Time of Week (hrs) JULY 23-25 Attic 1 T-30 DeckArmor UDL S/R 1/300 Attic 2 Polyicyene Sealed Attic 5 T-30 15lb LowPerm ASV 1/300

16% Higher Ceiling Temperature (5 C˚) HIGHER Flux Through Ceiling (NO INSULATION)

Sealed attic (RUS-22) has highest ceiling heat flux

Breathable membrane (16 perms)

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10 Managed by UT-Battelle for the U.S. Department of Energy

At AtticSIM ticSIM/Ene Energy y Plus Plus simula simulation tion mod model el

Roof Energy Balance

ASTM C 1340-99 Standard For Estimating Heat Gain of Loss Through Ceilings Under Attics

NET Attic 01 Benchmark

Miller et al. (2007), “Natural Convection Heat Transfer in Roofs with Above-Sheathing Ventilation.”

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Hot climates: ASHRAE zones 1, 2, and 3

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Roof and attics design

Insulated and Ventilated Shingle Roof Conventional or cool color shingle; 1-in. (0.0254-m) air space made by profiled and foil-faced 1-in. (0.0254-m) EPS insulation placed above deck (retrofit practice) or fitted between roof rafters (new construction); two low-e surfaces.

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13 Managed by UT-Battelle for the U.S. Department of Energy

Duct R-5.5 with 10% air leakage; thermostat 70 Heat / 74 Cool; 1:300 vent area

AtticSim/EnergyPlus estimated energy savings

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14 Managed by UT-Battelle for the U.S. Department of Energy

Retrofit options hot climate

Austin, TX

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15 Managed by UT-Battelle for the U.S. Department of Energy

New construction hot climate

Austin, TX

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16 Managed by UT-Battelle for the U.S. Department of Energy

Tracer gas testing used to compute ACH of attics

Regression analysis for decay rate of concentration yields ACH of 2.71

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17 Managed by UT-Battelle for the U.S. Department of Energy

Ventilation benchmark

  • Major assumption in using the AtticSim tool is the accuracy of the

ventilation prediction.

  • Simulations were run for test period when gas tracer analysis

performed.

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32 36.5 41 45.5 50 54.5 59 63.5 68 72.5 77 81.5 86 90.5 95 99.5 104 108.5 113

5 10 15 20 25 30 35 40 45 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Average Temperatures (°C) Time of Day (EST) Shingle Underlayment Sheathing Joist Outdoor (°F)

Control roof winter temperature profile

Data averaged in bin hours over the 3 winter months Jan through Mar

Attic Condensate Concerns

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19 Managed by UT-Battelle for the U.S. Department of Energy

Winter inter surf surface ace con conden densa sation tion pote potential ntial

Attic Hours Tsheath<Tdp (2015 total) % Time for Condensation

  • n Sheathing

Hours Tjoist<Tdp (2015 total) % Time for Condensation

  • n Joist

03 - NB 110 5.5% 72 3.6% 04 - CS 103 5.1% 62 3.1% 01 - CTRL 102 5.1% 48 2.4% 06 - RB 83 4.1% 26 1.3% 07 - FF 75 3.7% 32 1.6% 05 - ASV 20 1.0% 10 0.5%

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  • Outline of upcoming DOE work on cool roofs
  • Includes
  • Buildings level
  • Urban Level
  • Global Level
  • International activities

www.eereblogs.energy.gov/buildingenvelope

Cool r Cool roof

  • of road
  • adma

map

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21 Managed by UT-Battelle for the U.S. Department of Energy

  • Key accomplishments:
  • Cool roof selection guide
  • Cool roof calculator
  • DOE cool roof policy
  • Key upcoming work
  • Aged rating protocol
  • Advanced materials

Buildings Buildings le level el

81C 34C

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Cool roof selection guide

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23 Managed by UT-Battelle for the U.S. Department of Energy

  • Collaboration by ORNL

and LBNL with funding from DOE and CEC

  • Provides cool roof

assessments and advanced roof options

  • Runs full simulations
  • See RoofCalc.com

Roof

  • of sa

savings vings calcula alculator tor

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24 Managed by UT-Battelle for the U.S. Department of Energy

  • A low-sloped roof (pitch less than or equal to 2:12) must

be designed and installed with a minimum 3-year aged solar reflectance of 0.55 and a minimum 3-year aged thermal emittance of 0.75 in accordance with the Cool Roof Rating Council program, or with a minimum 3-year aged solar reflectance Index (SRI) of 64 in accordance with ASTM Standard E1980-01. Steep-sloped roofs (pitch exceeding 2:12) must have a 3-year aged SRI of 29 or higher.

  • Requires R30 Insulation
  • Required unless determined to be not economical by

life cycle cost analysis

DOE cool roof policy

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25 Managed by UT-Battelle for the U.S. Department of Energy

  • Key a

ey acc ccomp

  • mpli

lish shmen ments: ts:

  • Majo

Major liter r literatur ture e review view

  • Key u

ey upc pcoming

  • ming wor
  • rk
  • Stud

tudy y of

  • f u

urba rban n po poll llution ution a aba bateme tement nt

Urban l Urban level el

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26 Managed by UT-Battelle for the U.S. Department of Energy

Global Global le level el

Source: IPCC

Total emitted CO2 offset for cool roofs and cool pavements = 44 GT CO2

  • Key Accomplishments:
  • Peer Review Panel
  • Key Upcoming Work
  • Validation of Global

cooling models

  • India Project
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27 Managed by UT-Battelle for the U.S. Department of Energy

Design load chamber for simulating and accelerating roof contamination rate

  • Chamber built for

accommodating a sample size up to 15” in dia. or multiple samples of smaller area size

  • Real-time monitoring capability

for contaminant loading

  • Easy access to sample for

reflectance measurement and loading verification

  • Design for loading dry and or

wet contaminants

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28 Managed by UT-Battelle for the U.S. Department of Energy

Loading and reflectance reduction rates

  • Hi-fidelity simulation of

atmospheric dust loading using real-world test dusts, e.g., Arizona test dust(ISO 12103-1 standard)

  • Total surface reflectance

measurement tested on Arizona test dust Mass loading function linear (R2>0.9) following deposition theory

  • Reflectance reduction also

linear following dust load (R2 > 0.98)

R² = 0.9048

  • 0.5

0.5 1 1.5 2 2.5 0.0 20.0 40.0 60.0 80.0 Dirt Mass, g Loading Duration from To, min R² = 0.9807

  • 0.350
  • 0.300
  • 0.250
  • 0.200
  • 0.150
  • 0.100
  • 0.050

0.000 0.050 0.0 20.0 40.0 60.0 80.0 Reflectance Reduction Loading Duration from To, min

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Microbial analyses

  • Sampling protocols for

cultivation and nucleic acid analysis was tested at sites in TN, PA, and FL.

  • One sample from each site is

undergoing 454 sequencing analysis

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30 Managed by UT-Battelle for the U.S. Department of Energy

Chamber acquired to accelerate microbial growth

  • Chamber controls solar radiation,

temperature, humidity, wetting cycle acquired to perform exposure testing

  • Specimens loaded with dust and

inoculated with microbes will be inserted in chamber and evaluated

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31 Managed by UT-Battelle for the U.S. Department of Energy

Cool r Cool roof

  • of coa

coatings with tings with cer ceramics amics

  • Cool roof coatings are

promoted based on the presence of ceramic particles.

  • Unclear that particles

improve performance.

  • Tests begun in March 2010 of

four cool roof coating products.

  • Temperature and heat flux

through the roof measured to quantify performance.

reference black/white panels test panels with ceramic paints

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32 Managed by UT-Battelle for the U.S. Department of Energy

reference black/white panels test panels with ceramic paints

Sample data for sunny day, April 16, 2010 A coating with no ceramic beads (SRinitial = 0.88) keeps roof cooler than paints with ceramic particles (SRinitial about 0.8) . …and requires less cooling than other samples and heating penalty only relative to the black surface.

Cool r Cool roof

  • of coa

coating r ting results esults

20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 2 4 6 8 10 12 14 16 18 20 22 Temperature (oF) Time (hour) Paint B w/ ceramic particles Paint A w/ ceramic particles Paint D, no ceramic particles Paint C w/ ceramic particles White reference Black reference

black, Tmax =160oF white, Tmax= 92oF

paint w/ no particles, Tmax = 74oF

Roof membrane temps

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33 Managed by UT-Battelle for the U.S. Department of Energy

Performance of attic radiant barrier systems

Attic 1 Oriented strand board (OSB) without radiant barrier (RB), ε = 0.89 Attic 2 OSB with perforated foil faced RB, ε = 0.03 Attic 3 RB stapled to rafters, ε = 0.02 Attic 4 Spray applied low-e paint on roof deck and rafters, ε = 0.23

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34 Managed by UT-Battelle for the U.S. Department of Energy

Performance of attic radiant barrier systems

  • The test attic had RUS 13 fiberglass batt

insulation on the floor

  • Summer daytime condition: climate

chamber air temperature 100°F, roof exterior surface temperature 140°F

  • Winter Night condition: climate chamber air

temperature 32°F

  • Cooling load through

attics 2, 3, and 4 were 33%, 50%, and 19% lower than the load from attic 1 during summer daytime conditions

  • During winter

conditions, a 6 to 10% reduction in heat loss through the ceiling was observed

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35 Managed by UT-Battelle for the U.S. Department of Energy

Integrated PV-PCM roof

  • Evaluation of a roof system with (PV) laminates integrated

with metal panels and PCM.

  • Collaboration between Metal Construction Association,

CertainTeed, Uni-Solar, Phase Change Energy Solutions, and ORNL.

  • Shingle roof used as control for comparison and evaluation
  • f the PV-PCM roof.

Shingle Roof PV-PCM Roof

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36 Managed by UT-Battelle for the U.S. Department of Energy

PV-PCM roof construction

Metal panels with pre- installed PV laminates Bio-based PCM

  • n roof deck

Foil-faced fiberglass insulation 2-inch air gap for above-sheathing- ventilation (ASV).

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37 Managed by UT-Battelle for the U.S. Department of Energy

Winter data

Roof Heat Flux Attic Center Temperature

  • Substantially lower

heat flow through PV-PCM roof, and warmer attic.

  • Mid-day heat

addition increases the shingle attic temperature; possible heating penalty in PV-PCM.

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38 Managed by UT-Battelle for the U.S. Department of Energy

Summer data

  • Substantial lower

peak daytime heat addition through PV-PCM roof.

  • PV-PCM attic

temperatures show lower fluctuations; Also evident is a ~2 hr. peak shift.

Roof Heat Flux Attic Center Temperature

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39 Managed by UT-Battelle for the U.S. Department of Energy

  • Working in partnership with industry, DOE is

undertaking both development and enabling research in the roofing market to make available to building owners more energy efficient and affordable roofing system choices.

Closing summary

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Earthrise from Apollo 8 (December 24, 1968) We came all this way to explore the moon and the most important thing is that we discovered the Earth.“ Bill Anders, Apollo 8 Astronaut