Ben Larson 2 November th Avenue NE, Seattle, WA (206)
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
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
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
5 ClimateSingle Family Multi Family Portland Redmond Medford State Average System TypeSingle Family Multi-family Gas Furnace Gas Furnace with Cooling Heat Pump Electric Resistance Zonal
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 MF PrototypeWeight 952 crwl slab0.22 6
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
8 1 High efficiency walls & windows: Exterior walls – U / R-19+R-5 (sheathing) Windows-U-0.30 2 High efficiency envelope: Exterior walls – U / R-21 Flat ceilings – U / R-49 Framed floors – U / 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 / 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 (3), or ASHRAE 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
43 possible combinations of additional measures (after excluded combinations removed) 2394 independent simulation and calculation runs 9
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
11 *Excludes Solar Measures
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
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
14 ScenarioEqualHVACDHWMiddleLow Envelope Enhancemnt Measures 1Walls & Windows dEnvelope & Doors lEnvelope & Lights Ceiling, Window & Duct Sealing UA 15% Reduction Bldg Tightness & Duct Sealing Ducts Inside Conservation Measures AHVAC System Upgrade BDucts Inside CDHP D 75% CFLs & Demand-Gas DHW E75% CFLs & Duct Sealing FSolar PV GSolar Thermal Savings12.0%10.5%9.5%9.6%8.8%
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
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 ▪ ft 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
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 ft 2 3%510
An in-depth analysis not conducted because the population is small and extremely challenging to characterize A general analysis suggests an additional % 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% ft 2 New3-7% ft 2 None0%1 >600ft 2 New6-15%2 *Based on simplified test case simulations and calculations
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
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
1 High efficiency walls & windows: Exterior walls – U / 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 / R-21 Intermediate framing, and Vaulted ceilings – U / R-30, and Flat ceilings – U / R-49, and Framed floors – U / 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 / R-30, and Flat ceilings – U / 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 (3), or ASHRAE 62.2, and The dwelling shall be tested with a blower door and found to exhibit no more than: air changes per hour, or 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
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 N 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
ClimateSF / MFProtoHVACClimateSF / MFProtoHVACFinal Weight PDXsf1344gfnc PDXsf1344gfac PDXsf1344hp__ PDXsf1344zonl PDXsf2200gfnc PDXsf2200gfac PDXsf2200hp__ PDXsf2200zonl PDXsf2688gfnc PDXsf2688gfac PDXsf2688hp__ PDXsf2688zonl PDXmfc952gfnc PDXmfc952gfac PDXmfc952hp__ PDXmfc952zonl PDXmfs952zonl
26 ClimateSF / MFProtoHVACClimateSF / MFProtoHVACFinal Weight RDMsf1344gfnc RDMsf1344gfac RDMsf1344hp__ RDMsf1344zonl RDMsf2200gfnc RDMsf2200gfac RDMsf2200hp__ RDMsf2200zonl RDMsf2688gfnc RDMsf2688gfac RDMsf2688hp__ RDMsf2688zonl RDMmfc952gfnc RDMmfc952gfac RDMmfc952hp__ RDMmfc952zonl RDMmfs952zonl
ClimateSF / MFProtoHVACClimateSF / MFProtoHVACFinal Weight MFRsf1344gfnc MFRsf1344gfac MFRsf1344hp__ MFRsf1344zonl MFRsf2200gfnc MFRsf2200gfac MFRsf2200hp__ MFRsf2200zonl MFRsf2688gfnc MFRsf2688gfac MFRsf2688hp__ MFRsf2688zonl MFRmfc952gfnc MFRmfc952gfac MFRmfc952hp__ MFRmfc952zonl MFRmfs952zonl