Pilot Phase Documentation

Transcription

1 PHIUS Passive Building Standard Nrth America Pilt Phase Dcumentatin Versin March 2018 Passive Huse Institute US (PHIUS) 116 West Illinis Street, Suite 5E Chicag, IL (312) Passive Huse Institute US (PHIUS) PHIUS Pilt

2 PHIUS+ 2018: Getting t Zer In 2014, under a grant frm the U.S. Department f Energy (DOE), and in partnership with Building Science Crpratin, PHIUS develped PHIUS the first and nly climate specific passive building standard. The 2015 standard accunted nt nly fr substantial differences between climate znes, but als fr market and ther variables, retaining rigrus cnservatin gals, while making passive building mre ratinal and cst effective. PHIUS helped dramatically accelerate adptin. PHIUS recgnized that technlgies, market cnditins, carbn reductin gals and even climates culd change ver time. Cnsequently, PHIUS cmmitted t revising the standard t reflect such changes. PHIUS is the first updated revisin, and it will be phased in thrugh 2018 and will eventually replace PHIUS This update fcuses n adding mre nuance fr different building types, and supprting an verall transitin t renewable energy. What s the same: PHIUS remains a pass/fail passive building standard, serving as an update t replace PHIUS It remains a perfrmance-based energy standard that includes prescriptive quality assurance requirements adpted frm U.S. gvernment prgrams - Energy Star, Zer Energy Ready Hme, and EPA Indr airplus. The standard has three pillars, r marquee-level requirements Limits n heating/cling lads (bth peak and annual) Limit n verall surce energy use Air-tightness and ther prescriptive quality assurance requirements PHIUS recgnized that there are diminishing returns n investment in energy-cnserving measures, and an ptimum level in a life-cycle cst sense. Climate plays a large rle in determining where that pint is. Fr PHIUS+ 2015, researchers studied ptimizatin in 110 cities, and develped interplatin frmulas t set heating and cling (space-cnditining) energy targets fr cities acrss the US and Canada. The same criteria applied t buildings f all sizes. Passive Huse Institute US (PHIUS) PHIUS Pilt 2

3 What s the same: The verall energy limit under PHIUS is based n surce energy, rather than site energy, as it is a better prxy fr resurce cnsumptin and emissins assciated with the site s energy use. The surce energy limit is nt set based n cst ptimizatin, but rather n the fair share f carbn emissins allwed fr each sectr. T limit glbal warming with sme certainty, emissins must g t zer verall and the energy system must g t 100% renewable. New in PHIUS+ 2018: Under the pilt release f PHIUS+ 2018, the space-cnditining targets are less granular in terms f climate - they are instead set zne-by-zne, using the 17-climate-zne system referenced in the Internatinal Energy Cnservatin Cde (IECC). New in PHIUS+ 2018: Because size and ccupant density influence the ptimal path t a lw energy building, the new criteria implement cntinuus adjustments fr a range f different building sizes and ccupant densities. Fr example: A 2,000 sf single-family hme des nt have the same ptimal space cnditining energy perfrmance targets as a 200,000 sf twer, even if they have the same ccupant density. That s because the tw have different envelpe-t-flr area ratis. Cnservatin imprvements are generally applied t the envelpe, but ventilatin effects fllw ccupancy and flr area, and perfrmance targets are set per square ft f flr area. This means that tw side-by-side 10,000 sf buildings, in the same lcatin, with different ccupant densities will have slightly different space cnditining targets. The space cnditining criteria result frm ptimizing based n upgrade csts vs. savings in peratinal energy, and guide building energy planners accrdingly. (As with PHIUS+2015, the ptimizatin studies include sme frced upgrades, ntably n air-sealing and windws, but windw csts have cme dwn cnsiderably in the past few years, and designers still have flexibility t meet the resulting perfrmance targets in different ways.) New in PHIUS+ 2018: In PHIUS+ 2018, the surce energy criterin is tightened, with a view tward zer, but there are mre ptins fr meeting it. There is n cap n ttal surce energy use, as lng as the predicted annual net surce energy use meets the new (lwer) target. This net surce energy use is the Passive Huse Institute US (PHIUS) PHIUS Pilt 3

4 remaining surce energy use, after what is ffset by qualified renewable energy measures, n-site and ff-site. Previusly, ff-site renewable energy was nt accunted fr, and nly a fractin f n-site renewable energy was cunted t ffset surce energy use (exprts did nt cunt.) Hwever, in tapering the surce energy limit t zer, it is unprductive t put the entire burden n the building and its n-site prductin ptential. Ding s may push past the pint f diminishing returns in energy cnservatin, r prhibit prjects with cnstrained sites frm ever achieving this gal. At sme pint, the building has cnserved and generated all it can, and the fcus will shift t cleaning up the energy supply. Therefre, ff-site ptins such as Virtual Pwer Purchase Agreements, cmmunity renewables, directly wned ff-site, and renewable energy credits are valid measures f ffsetting a prject s surce energy use under PHIUS PHIUS is intended t guide designers tward a cst-effective investment in building envelpe and ther passive measures, while giving a wide range f ptins fr the must-d jb f cntributing t an verall transitin t renewable energy. The pilt prgram f PHIUS is intended t assess hw the new perfrmance requirements fit fr a variety f prjects. The climate and ccupant sensitivity may be revisited and refined fr the final prgram. PHIUS+2018 pilt phase - changes frm 2015 Public cmment is particularly encuraged n items highlighted in green. Certificatin criteria Heating and cling The climate sensitivity is less granular - it changes frm cntinuus t zne-by-zne, using the 17 climates f the ASHRAE 169 / IECC system. (Cntinuus sensitivity t climate factrs may be restred fr the final 2018 prtcl.) The criteria are adjusted fr building size and ccupant density. The adjustments are cntinuus within a limited range. The sensitivities are different fr each f the fur criteria, in each climate zne. See the summary table at the end f this dcument fr examples and this Space Cnditining Criteria Estimatin Tl t estimate prject criteria. The prject s exact criteria are based n Envelpe Area t Flr Area rati: Passive Huse Institute US (PHIUS) PHIUS Pilt 4

5 'Envelpe / icfa' is the building's exterir envelpe area divided by the interir cnditined flr area. The building envelpe area and flr area must be in the same units. The envelpe area can be calculated manually r fund in yur WUFI Passive mdel under the results reprt r visualized cmpnents branch. 'Square feet per persn' must be calculated using ttal ccupancy divided by icfa (interir cnditined flr area). Space Cnditining Criteria Calculatr As befre, the same targets generally apply t bth residential and nn-residential buildings. Fr unique nn-residential buildings with significant prcess lads, very high internal lads, r highly variable ccupancy, custm ptimizatin may be needed t determine the apprpriate targets. This will be dne n a case-by-case basis using BEpt. An additinal certificatin fee will apply. Exceptin: Fr the pilt phase nly, certificatin staff has discretin t grant an exceptin n ne f the five main perfrmance criteria (heating/cling r surce energy). Ttal energy use The certificatin limit is reduced frm 6200 t 3840 kwh/p fr residential, and frm 38.1 t 34.8 kbtu/ft2 fr nn-residential. This is intended t taper t zer in years t cme, with dwnward revisins n a three year cycle, the next cming in The zer year is nt yet decided. There is a change t the surce energy metric. It is nw calculated as the net f annual n-site and ff-site renewable prductin. All f the predicted annual nsite-renewable electricity generatin is nw regarded as ffsetting surce energy use, nt just the fractin used right away r stred and used n-site. Sme arrangements fr prcuring ff-site renewable energy are nw als regarded as ffsetting the surce energy use, as fllws: Directly-wned ff-site renewables. Cmmunity renewable energy. Virtual Pwer Purchase Agreements. Green-E Certified Renewable Energy Certificates (RECs), discunted 80%, that is, each 1 kwh purchased ffsets 0.2 kwh. The building wner must present an actual cntract fr prcurement f renewable energy, Passive Huse Institute US (PHIUS) PHIUS Pilt 5

6 sufficient t meet the target (at time f certificatin), fr 20 years. The surce energy multiplier fr grid electricity is aligned with Energy Star Prtfli Manager fr USA, 2.05 fr Canada. This factr is als intended t be rechecked every three years. Prjects that are ff-grid fr indr water supply and fr wastewater treatment have a prcess lad allwance f 800 kwh/p.yr fr residential prjects, 14 kwh/kgal fr nnresidential (half that if a prject is ff-grid fr water supply nly r wastewater treatment nly.) (PHIUS Ht Water Calculatr v1.1.xlsx) Quality assurance The air-tightness certificatin limit fr mst buildings is increased frm 0.05 t 0.06 cfm50 per ft2 f envelpe. (The criterin fr tall buildings f nncmbustible cnstructin remains the same.) The requirement that the ventilatin system is capable f 0.3 ACH is remved. Canada prjects are exempt frm the Indr airplus materials checklist requirements. Initial prtcl fr cmmissining f nnresidential buildings is fcused n energy use impacts: Infiltratin testing. Ventilatin balancing and wattage measurement. Ducted heating/cling balancing. Verificatin f envelpe, air barrier, thermal bridge mitigatin, and shading - built t plans. Verificatin f lighting, mechanical, and prcess lad systems per plans/energy mdel. Energy mdeling prtcl Building energy mdels must be submitted in WUFI Passive, using a versin which supprts the new slar shading algrithm. The requirement that the ventilatin system is mdeled at a minimum f 0.3 ACH is remved. (Supply per persn and exhaust-rm minimums still apply, per Certificatin Guidebk sectin 6.7.) If a cling system is planned, n natural ventilatin cling is t be included in the mdel. Passive Huse Institute US (PHIUS) PHIUS Pilt 6

7 The fllwing changes t the calculatin prtcl fr ht water energy use are implemented in a new accessry calculatr wrkbk: Calculatin supprt fr meeting EPA Watersense delivery time requirement. Revised pipe heat lss calculatin scales mre realistically t larger buildings. Alignment with RESNET n lw-flw fixture credit, drain water heat recvery, washer/dryer/dishwasher energy calculatins, and mnthly cld water inlet temperature variatin. PHIUS+ 2018, target-setting prcess fr heating and cling As fr PHIUS+ 2015, the basic prcess fr setting the heating and cling criteria was: 1. Life-cycle cst ptimizatin: Mdel study buildings in BEpt, giving its ptimizer varius energy-saving upgrades t weigh. 2. Crssver: Mdel the study buildings again in WUFI Passive, with the chsen upgrade packages. This is necessary t tune the criteria t the calculatin methds actually used in prject certificatin. 3. Statistical smthing: Nte the resulting annual demands and peak lads fr heating and cling and d curve-fitting n that data t find interplatin frmulas. Thse frmulas then determine the criteria fr all cases. Fr 2018, there were five different study buildings: a small 24x25 ft tw-stry huse f abut 1000 square feet flr area a typical 26x40 ft tw-stry huse f abut 1800 sf, and three apartment buildings - all 152x56 ft, but in 4,6, and 10 stry versins, up t abut sf. In terms f size and windw-t-wall rati, the large apartments crrespnd t the US DOE Cmmercial Prttype buildings fr Mid-rise and High-rise Apartment. Each f these five gemetries was set up fr three different ccupant densities, crrespnding as clsely as pssible t 235, 370, and 875 square feet per persn, making fr a ttal f 15 base buildings in BEpt. In sme cases the density was adjusted by changing the number f bedrms per unit, and in sme cases by changing the number f units per flr. By default, BEpt runs its dynamic simulatins accrding t Building America Huse Simulatin Passive Huse Institute US (PHIUS) PHIUS Pilt 7

8 Prtcl. Sme glbal verrides were applied t align with PHIUS mdeling prtcl, such as the heating and cling setpint temperatures, and the lighting, plug lad, and ht water usage assumptins. Sme significant energy-saving upgrades were als impsed - ducts inside, stringent air-sealing, and windw U-values lw enugh t keep their inside surface temperature within 4 C (7.2F) f the indr air, at a winter extreme cnditin (12-hur mean minimum utdr temperature.) PV generatin was essentially excluded frm the calculatin; that is, the ptimizatin lked nly at the diminishing returns behavir f the cnservatin measures, bth envelpe and HVAC. Each f the 15 base buildings was ptimized in the 17 representative cities fr the climate znes (which are als listed n the DOE Cmmercial Prttype Buildings website), fr a ttal f 255 individual cases studied. T chse the upgrade package, the ptimal, minimum life-cycle cst pint was chsen fr all cases, rather than manually chsing a pint f diminishing returns n the cst curve as befre. In the first rund f the crssver study, the 255 ptimized buildings were re-mdeled in WUFI Passive, adding nly a few effects frm PHIUS prtcl that BEpt neglects, such as windw installatin thermal bridge cefficients, and crridr ventilatin. After review by the Tech Cmmittee, sme additinal adjustments were made t the WUFI Passive mdels in tw areas where crrespndence with BEpt was deemed mst prblematic: natural ventilatin was remved, and perimeter type fundatin insulatin was replaced with thin whleslab insulatin. Als, air-sealing was further tightened and IECC 2015 cde minimums were cnsistently impsed fr the main assemblies (flr, wall, rf). In the curve-fitting, each f the fur criteria was fitted t a nnlinear but piecewise-cntinuus functin f the Envelpe-t-Flr-area rati. The functin has three pieces - cvering the tw small buildings, the three large buildings, and in-between. The sensitivity t ccupancy is mdeled as an additive (superimpsed) effect, but it can act differently in each f the three size ranges f Envelpe-t- Flr-area rati. This was dne separately fr each climate zne, fr a ttal f 4x17=68 fittings. The mdel frmula has ten adjustable parameters and there are fifteen data pints per zne, thus 15 minus 10 = five degrees f freedm fr estimatin f errr, in statistics jargn. In mre familiar terms, what s been dne statistically is similar t fitting a straight line thrugh three data pints, fr each f the fur heating/cling criteria, in each climate zne, thugh in fact sme nnlinear (quadratic) effects are captured. Passive Huse Institute US (PHIUS) PHIUS Pilt 8

9 1A 1B 2A 2B 3A 3B 3C 4A 4B 4C 5A 5B 5C Building Size (ft2) 2,000 5,000 10,000 20,000 50, , ,000 Occupancy High Med Lw High Med Lw High Med Lw High Med Lw High Med Lw High Med Lw High Med Lw Occupancy (ft2/persn) Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad

10 6A 6B 7 8 Building Size (ft2) 2,000 5,000 10,000 20,000 50, , ,000 Occupancy High Med Lw High Med Lw High Med Lw High Med Lw High Med Lw High Med Lw High Med Lw Occupancy (ft2/persn) Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad Heating Demand Cling Demand Heating Lad Cling Lad