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Ben Larson 2 November 2010 ben@ecotope.com 4056 9 th Avenue NE, Seattle, WA 98105 (206) 322-3753
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Background: New Oregon residential energy code proposal analysis. The OR-BCD has asked the RTF and Ecotope to produce a savings estimate. Last Meeting: Presented methodology Goals Today: Present analysis findings & recommendations Obtain approval of predicted savings 2
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Code revision goal is to reduce whole-house energy use by 10% over the 2008 code. Code covers single family detached and multi-family dwellings 3 stories or less. 3
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Determine representative characteristics of housing population including: Climates Single Family (SF) and Multifamily (MF) occupancies HVAC systems Prototype buildings Compile base case and proposed code requirements Calculate annual energy use for the representative housing population. End uses considered include: Heating, Cooling, Ventilation, Lighting, and DHW Weight calculation outputs together based on housing population data 4
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5 ClimateSingle Family Multi Family Portland 0.590.19 Redmond 0.150.01 Medford 0.060.01 State Average 0.790.21 System TypeSingle Family Multi-family Gas Furnace0.26 0.12 Gas Furnace with Cooling0.56 0.2 Heat Pump0.09 0.05 Electric Resistance Zonal0.09 0.63
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Single Family unchanged from 28 September: 1344ft 2 – Single story over crawl space 2688ft 2 – Like 1344, but over a conditioned basement 2200ft 2 – 1.5 story split level with garage and bonus room (over crawl) Updated: Multifamily prototype is a single unit in an eight unit townhouse complex. Prototype used in previous OR analysis (at least as early as 1990) 952ft 2 conditioned area per unit (stacked units, 4 on bottom, 4 on top) Both slab-on-grade and crawl space modeled Net result: 51 different house types resulting from combination of climates, prototypes, and heating systems. SF PrototypeWeight 13440.15 22000.75 26880.1 MF PrototypeWeight 952 crwl0.78 952 slab0.22 6
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Code proposal uses the existing core prescriptive requirements from 2008 (but does add provision for heat pump aux heat outdoor temperature lockout) The new code savings come from a revised set of additional measure tables. The code will require the selection of two measures. The measures are divided into two categories with one measure being selected from each category. ▪ Envelope Enhancement Measures (6 options) ▪ Conservation Measures (7 options) 7
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8 1 High efficiency walls & windows: Exterior walls – U-0.047 / R-19+R-5 (sheathing) Windows-U-0.30 2 High efficiency envelope: Exterior walls – U-0.058 / R-21 Flat ceilings – U-0.025 / R-49 Framed floors – U-0.025 / R-38 Windows – U-0.30 Doors- All U-0.20, or Add’l 15% high-efficacy lamps 3 High efficiency ceiling, windows & duct sealing: Flat ceilings – U-0.025 / R-49, and Windows-U-0.30, and Performance tested duct systems 4 High efficiency thermal envelope UA: Proposed UA is 15% lower than the Code UA 5 Building tightness testing, ventilation & duct sealing: A mechanical system providing ventilation rates specified in Table 1101.1(3), or ASHRAE 62.2. Blower door testing to 6.0 air changes per hour. Performance tested duct systems. 6 Ducted HVAC systems within conditioned space A High efficiency HVAC system: AFUE of 90% gas furnace HSPF of 8.5 heat pump (SEER 13) B Ducted HVAC systems within conditioned space C Ductless heat pump: DHP in primary zone with HSPF 8.5 (resistance heat allowed in secondary zones). PTHP with comparable efficiency ratings (no supplemental zonal heaters installed in the building) and integrated backup resistant heat is allowed in a PTHP. D High efficiency water heating & lighting: Gas tankless EF of 0.80, and 75% CFLs E Energy management device & duct sealing: Performance tested duct systems, and 75% CFLs F Solar photovoltaic: Minimum 1 Watt / ft 2 conditioned floor space G Solar water heating: Minimum of 40 ft 2 of gross collector area Envelope Enhancement Measures Conservation Measures
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43 possible combinations of additional measures (after excluded combinations removed) 2394 independent simulation and calculation runs 9
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The savings for each measure is a weighted sum of all the house types across the state Analysis estimates of measure combinations: 14 achieve 6-9% savings 3 achieve 9-10% savings 26 achieve 10-39% ▪ high savings due to certain DHP measure combinations ▪ without DHP, savings is 10-17% Next slide shows the savings for each measure combination. Solar measures left off the table but are included in the overall analysis. 10
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11 *Excludes Solar Measures
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In practice, housing market will be built with an uneven selection of these measure combinations Therefore, the overall savings will be a set of the measure combinations. ▪ Selection likely to be driven by cost and minimum perturbation to existing practices. Some emerging technologies, however, (DHPs, tankless & heat pump water heaters) may alter market dynamics. Due to (obvious) lack of data of future market behavior, we conducted a sensitivity analysis examining different possible scenarios of measure combination selections 12
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Equal – combinations selected with equal likelihood (not realistic) HVAC – furnace, ducted heat pump, and ductless heat pumps upgrade options widely selected DHW – tankless gas water heater preferentially selected Middle– middle of the road scenario Low – lowest (worst case) likely savings scenario where builders select options that save the least All scenarios bounded by some constraints such as known population of ducted houses, basements, etc. 13
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14 ScenarioEqualHVACDHWMiddleLow Envelope Enhancemnt Measures 1Walls & Windows0.140.070.100.020.07 2dEnvelope & Doors0.140.070.100.110.09 2lEnvelope & Lights0.140.070.100.110.09 3 Ceiling, Window & Duct Sealing0.140.070.100.030.02 4UA 15% Reduction0.140.070.100.03 5Bldg Tightness & Duct Sealing0.140.40 0.500.60 6Ducts Inside0.140.250.100.200.10 Conservation Measures AHVAC System Upgrade0.140.750.520.710.70 BDucts Inside0.140.01 0.00 CDHP0.140.130.100.080.05 D 75% CFLs & Demand-Gas DHW0.140.050.300.180.19 E75% CFLs & Duct Sealing0.140.050.060.010.05 FSolar PV0.140.01 GSolar Thermal0.140.01 Savings12.0%10.5%9.5%9.6%8.8%
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The explored scenarios deliver a savings range from 8.8% to 10.5%. The middle scenario shows savings of 9.6% A savings of at least 9.5% generally holds for other scenarios and combinations (not shown here) Savings are still short of 10% target, but there is another source… 15
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Proposed code changes include provisions for improving house addition and remodel energy performance. 2008 version additions: ▪ <400ft 2 core requirements only ▪ >400ft 2 core requirements plus one additional measure (like new construction) Proposed changes for additions: ▪ <200ft 2 core requirements only ▪ 200-600ft 2 core requirements plus one additional measure ▪ >600ft 2 core requirements plus two additional measures (like new construction) Remodel changes not modeled but there are significant changes ▪ Windows: U-0.65 U-0.35 ▪ Doors: R-2 R-5 ▪ Flat ceilings: R-38 R-49 ▪ Slab perimeter: R10 R-15 ▪ Underfloor: ≥2x10 Joist R-21 R-30, ≤2x8 Joist R-21 R-25 16
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Share of single family new construction based on floor area Data from Construction Monitor for Clackamas, Columbia, Marion, Multnomah, Polk, Tillamook, Washington, and Yamhill Counties in 2009 ▪ Additional permit activity not counted in table: remodels (1516), additions with no reported square footage (815), and change of occupancy (617). There is an extensive set of possible combinations for constructing a code-compliant addition. The savings contribution will be small but likely not entirely insignificant. 17 TypePercentn New Buildings92%3016 Additions > 600 ft 2 5%480 Additions 200-600ft 2 3%510
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An in-depth analysis not conducted because the population is small and extremely challenging to characterize A general analysis suggests an additional 0.2-0.5% savings is possible from the most promising sources. Includes the window upgrade for remodels and the effect of additions shown in the table below. 18 AreaSavings TypeSavings estimate* Add’l measures >200ft 2 None0%0 200-400ft 2 New3-7%1 400-600ft 2 None0%1 >600ft 2 New6-15%2 *Based on simplified test case simulations and calculations
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New construction from code proposal is likely to see a reduction in site energy use of 9-10% based on the sensitivity analysis of probable measure selection. The proposals to improve performance of remodels and additions is likely to provide extra savings (~0.5%). Decision: The probability the Oregon residential code proposal will realize the 10% target is ? A. Very probable B. Reasonably probable C. Highly improbable 19
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Envelope Measures 1-3: Window from U-0.30 to U-0.28 or U-0.25 Furnace AFUE from 90 to 92 House Infiltration in Envelope Measure 5 from 6ach50 to 5ach50 21
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Heating and Cooling with SEEM Ventilation with SEEM and side calculations Building tightness measure requires mechanical ventilation Lighting based on LPD and 1.5 hr/day on time DHW use based on average SF and MF occupancy of 2.5 and 1.8 people per unit respectively Energy of hot water used is ~1150 kWh/yr/person (~22 gal/day) MELs excluded from the analysis per OR BCD request 22
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1 High efficiency walls & windows: Exterior walls – U-0.047 / R-19+5 (insulation sheathing) / SIPS, and Windows – Max 15% of conditioned area; or Windows-U-0.30 2 High efficiency envelope: Exterior walls – U-0.058 / R-21 Intermediate framing, and Vaulted ceilings – U-0.033 / R-30, and Flat ceilings – U-0.025 / R-49, and Framed floors – U-0.025 / R-38, and Windows – U-0.30; and Doors- All doors U-0.20, or Additional 15 percent of permanently installed lighting fixtures as high-efficacy lamps 3 High efficiency ceiling, windows & duct sealing: (Cannot be used with Conservation Measure E) Vaulted ceilings – U-0.033 / R-30, and Flat ceilings – U-0.025 / R-49, and Windows-U-0.30 Windows- U-0.30, and Performance tested duct systems 4 High efficiency thermal envelope UA: Proposed UA is 15% lower than the Code UA when calculated in Table N1104.1(1) 5 Building tightness testing, ventilation & duct sealing: A mechanical exhaust, supply, or combination system providing whole-building ventilation rates specified in Table 1101.1(3), or ASHRAE 62.2, and The dwelling shall be tested with a blower door and found to exhibit no more than: 1. 6.0 air changes per hour, or 2. 5.0 air changes per hour when used with Conservation Measure E, and Performance tested duct systems 6 Ducted HVAC systems within conditioned space: (Cannot be used with Conservation Measure B or C) All ducts and air handler are contained within building envelope 23
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A High efficiency HVAC system: Gas-fired furnace or boiler with minimum AFUE of 90% a, or Air-source heat pump with minimum HSPF of 8.5 or Closed-loop ground source heat pump with minimum COP of 3.0 B Ducted HVAC systems within conditioned space: All ducts and air handler are contained within building envelope C Ductless heat pump: Replace electric resistance heating in at least the primary zone of dwelling with at least one ductless mini-split heat pump having a minimum HSPF of 8.5. Unit shall not have integrated backup resistance heat, and the unit (or units, if more than one is installed in the dwelling) shall be sized to have capacity to meet the entire dwelling design heat loss rate at outdoor design temperature condition. Conventional electric resistance heating may be provided for any secondary zones in the dwelling. A packaged terminal heat pump (PTHP) with comparable efficiency ratings may be used when no supplemental zonal heaters are installed in the building and integrated backup resistant heat is allowed in a PTHP. D High efficiency water heating & lighting: Natural gas/propane, on-demand water heating with min EF of 0.80, and A minimum 75 percent of permanently installed lighting fixtures as CFL or linear fluorescent or a min efficacy of 40 lumens per Watt as specified in Section N1107.2 E Energy management device & duct sealing: Whole building energy management device that is capable of monitoring or controlling energy consumption, and Performance tested duct systems, and A minimum 75 percent of permanently installed lighting fixtures as high-efficacy lamps F Solar photovoltaic: Minimum 1 Watt / ft2 conditioned floor space G Solar water heating: Minimum of 40 ft2 of gross collector area 24
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ClimateSF / MFProtoHVACClimateSF / MFProtoHVACFinal Weight PDXsf1344gfnc0.7770.750.150.260.023 PDXsf1344gfac0.7770.750.150.560.050 PDXsf1344hp__0.7770.750.150.090.008 PDXsf1344zonl0.7770.750.150.090.007 PDXsf2200gfnc0.7770.75 0.260.114 PDXsf2200gfac0.7770.75 0.560.248 PDXsf2200hp__0.7770.75 0.090.039 PDXsf2200zonl0.7770.75 0.090.037 PDXsf2688gfnc0.7770.750.10.260.015 PDXsf2688gfac0.7770.750.10.560.033 PDXsf2688hp__0.7770.750.10.090.005 PDXsf2688zonl0.7770.750.10.090.005 PDXmfc952gfnc0.7770.250.780.120.018 PDXmfc952gfac0.7770.250.780.200.030 PDXmfc952hp__0.7770.250.780.050.007 PDXmfc952zonl0.7770.250.780.630.094 PDXmfs952zonl0.7770.250.221.000.042 25
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26 ClimateSF / MFProtoHVACClimateSF / MFProtoHVACFinal Weight RDMsf1344gfnc0.1540.940.150.26070.006 RDMsf1344gfac0.1540.940.150.56430.012 RDMsf1344hp__0.1540.940.150.08970.002 RDMsf1344zonl0.1540.940.150.08530.002 RDMsf2200gfnc0.1540.940.750.26070.028 RDMsf2200gfac0.1540.940.750.56430.062 RDMsf2200hp__0.1540.940.750.08970.010 RDMsf2200zonl0.1540.940.750.08530.009 RDMsf2688gfnc0.1540.940.10.26070.004 RDMsf2688gfac0.1540.940.10.56430.008 RDMsf2688hp__0.1540.940.10.08970.001 RDMsf2688zonl0.1540.940.10.08530.001 RDMmfc952gfnc0.1540.060.780.120.001 RDMmfc952gfac0.1540.060.780.20.001 RDMmfc952hp__0.1540.060.780.050.000 RDMmfc952zonl0.1540.060.780.630.004 RDMmfs952zonl0.1540.060.2210.002
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ClimateSF / MFProtoHVACClimateSF / MFProtoHVACFinal Weight MFRsf1344gfnc0.0680.930.150.26070.002 MFRsf1344gfac0.0680.930.150.56430.005 MFRsf1344hp__0.0680.930.150.08970.001 MFRsf1344zonl0.0680.930.150.08530.001 MFRsf2200gfnc0.0680.930.750.26070.012 MFRsf2200gfac0.0680.930.750.56430.027 MFRsf2200hp__0.0680.930.750.08970.004 MFRsf2200zonl0.0680.930.750.08530.004 MFRsf2688gfnc0.0680.930.10.26070.002 MFRsf2688gfac0.0680.930.10.56430.004 MFRsf2688hp__0.0680.930.10.08970.001 MFRsf2688zonl0.0680.930.10.08530.001 MFRmfc952gfnc0.0680.070.780.120.000 MFRmfc952gfac0.0680.070.780.20.001 MFRmfc952hp__0.0680.070.780.050.000 MFRmfc952zonl0.0680.070.780.630.002 MFRmfs952zonl0.0680.070.2210.001 27
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