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

Roofing Systems in the 21 st Century; DOE’s 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 and growing 40% of U.S. Primary Energy Consumption Buildings Drive Electricity Supply (39% of U.S. Carbon Emissions) Investment Industry 3000 Buildings 377 MMTC 658 MMTC Buildings (25%) 2500 Industry (43%) Sales (Billion kWh) 2000 1500 1000 500 0 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 Source: 2007 Buildings Energy Data Book. Tables 1.1.3, 1.2.3, 1.3.3 Source: EIA Annual Energy Review, Table 8.9, June 2007 73% of U.S. Electricity Buildings Energy Use Growing Fastest 45 Industrial 40 Transportation Buildings Total 35 30 34% of Natural Gas Directly (55% Incl. Gen) 25 Quads 20 15 10 5 0 1980 1985 1990 1995 2000 2005 2 Managed by UT-Battelle Year for the U.S. Department of Energy

Roofs and attics project is a highly leveraged public-private partnership 3 Managed by UT-Battelle for the U.S. Department of Energy

FY11 FY11-12 k 12 key tasks and mil ey tasks and milestones estones • 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 4 Managed by UT-Battelle for the U.S. Department of Energy

NET NET facility acility use used d to to evalua valuate te attic ttic systems systems Low density Cool Non Perm membrane Low perm foam, 15-lb felt shingles breathable 15-lb felt 15-lb felt Adhered 2 3 4 5 6 1 7 Fascia Sealed 1/300 1/300 ASV 1/300 1/300 1/150 Radiant barrier 5 Managed by UT-Battelle for the U.S. Department of Energy

Instrumenta Instr umentation plan tion plan Temp Roof surface, underlayment, deck Rh Underlayment, deck, rafters, Insulation Heat flux Roof deck, attic floor Temp Air Pressure Air South T2,RH1 P2 T1 T6 (under felt) T7,RH5 (under felt) T4,R3 (joist) T13 Single Bay HFT2 HFT1 T12 T14 T9,RH7 (joist) T3,RH2 T10,RH8 (sheathing underside) T8,RH6 T11 T5,RH4 (sheathing underside) T15 P3 P1 HFT3 T16 These sensors are all in the • In each bay Same vertical plane, both sides • 8 temperature sensors, 6 Rh sensors, 3 heat flux sensors • Total 17 sensors per bay + 7 for air temperature and Rh 6 Managed by UT-Battelle • 3 attic pressure and 3 sensors for insulation = 30 sensors per bay for the U.S. Department of Energy

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

Sealed attic (R US -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 South Roof Deck Heat Attic Air Flux (W/m 2 ) Temperature (C˚) Lower Attic Air Solid Lines Dashed Lines Temperature (20 C ˚) 55 160 50 45 140 40 120 35 100 30 25 80 20 60 15 10 40 5 20 0 0 -5 0 24 48 72 71% Lower Flux Through Roof Deck 8 Managed by UT-Battelle for the U.S. Department of Energy

Sealed attic (R US -22) has highest ceiling heat flux Breathable membrane (16 perms) Attic 1 T-30 DeckArmor UDL S/R 1/300 16% Higher Ceiling Attic 2 Polyicyene Sealed Ceiling Temperature (C ˚ ) Ceiling Heat Flux (W/m 2 ) Temperature (5 C ˚) Dashed Lines Attic 5 T-30 15lb LowPerm ASV 1/300 Solid Lines 27 32 26 28 25 24 24 23 20 22 16 21 20 12 19 8 18 4 17 0 16 0 24 48 72 HIGHER Flux Through Time of Week (hrs) JULY 23-25 Ceiling (NO INSULATION) 9 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 ASTM C 1340-99 Standard For Estimating Heat Gain of Loss Through Ceilings Under Attics NET Attic 01 Benchmark Roof Energy Balance Miller et al. (2007), “ Natural Convection Heat Transfer in Roofs with Above-Sheathing Ventilation . ” 10 Managed by UT-Battelle for the U.S. Department of Energy

Hot climates: ASHRAE zones 1, 2, and 3 11 Managed by UT-Battelle for the U.S. Department of Energy

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

AtticSim/EnergyPlus estimated energy savings Duct R-5.5 with 10% air leakage; thermostat 70 Heat / 74 Cool; 1:300 vent area 13 Managed by UT-Battelle for the U.S. Department of Energy

Retrofit options hot climate Austin, TX 14 Managed by UT-Battelle for the U.S. Department of Energy

New construction hot climate Austin, TX 15 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 16 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. 17 Managed by UT-Battelle for the U.S. Department of Energy

Control roof winter temperature profile Data averaged in bin hours over the 3 winter months Jan through Mar 45 113 Shingle 108.5 40 Underlayment 104 Sheathing 99.5 Joist 35 95 Average Temperatures ( ° C) Outdoor 90.5 30 86 81.5 ( ° F) 25 77 72.5 20 68 63.5 15 59 54.5 10 50 Attic Condensate 45.5 Concerns 5 41 36.5 0 32 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time of Day (EST) 18 Managed by UT-Battelle for the U.S. Department of Energy

Winter inter surf surface ace con conden densa sation tion pote potential ntial % Time for Hours % Time for Hours Condensation T joist <T dp (2015 Condensation Attic T sheath <T dp on Sheathing total) on Joist (2015 total) 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% 19 Managed by UT-Battelle for the U.S. Department of Energy

Cool r Cool roof oof road oadma map • Outline of upcoming DOE work on cool roofs • Includes • Buildings level • Urban Level • Global Level • International activities www.eereblogs.energy.gov/buildingenvelope 20 Managed by UT-Battelle for the U.S. Department of Energy

Buildings Buildings le level el • Key accomplishments: • Cool roof selection guide • Cool roof calculator 81C • DOE cool roof policy • Key upcoming work • Aged rating protocol • Advanced materials 34C 21 Managed by UT-Battelle for the U.S. Department of Energy

Cool roof selection guide 22 Managed by UT-Battelle for the U.S. Department of Energy

Roof oof sa savings vings calcula alculator tor • 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 23 Managed by UT-Battelle for the U.S. Department of Energy

DOE cool roof policy • 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 24 Managed by UT-Battelle for the U.S. Department of Energy

Urban l Urban level el • Key a ey acc ccomp ompli lish shmen ments: ts: • Majo Major liter r literatur ture e review view • Key u ey upc pcoming oming wor ork • Stud tudy y of of u urba rban n poll po llution ution a aba bateme tement nt 25 Managed by UT-Battelle for the U.S. Department of Energy

Global Global le level el • Key Accomplishments: • Peer Review Panel • Key Upcoming Work • Validation of Global cooling models • India Project Source: IPCC Total emitted CO 2 offset for cool roofs and cool pavements = 44 GT CO 2 26 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 27 Managed by UT-Battelle for the U.S. Department of Energy