1. Ben Larson 19 July2010 ben@ecotope.com 4056 9 th Avenue NE, Seattle, WA 98105 (206) 322-3753 Fax: (206) 325-7270

2.  Today’s topic – energy use modeling for the residential sector. ▪ This covers the process used by Ecotope in recent work including: ▪ WA Energy Code, ▪ Northwest Power Council 6 th Power Plan ▪ OR Energy Code  Modeling goals: predict energy savings across the sector for one (or a group of) efficiency measure(s).  To model an entire sector, one needs to use minimum, average, and typical characteristics: ▪ Ex: Minimum – code ceiling insulation requirement ▪ Ex: Average – # of hours lights are on per day ▪ Ex: Typical – weather data  To make problem tractable, simplifying assumptions are needed (to be indicated throughout discussion)

3.  Assemble prototypes to represent new construction building population  Choose appropriate weather data  Determine base case characteristics (code levels)  Compile sets of efficiency measures to examine ▪ Building Shell ▪ Lighting ▪ HVAC and Duct Systems ▪ Domestic Hot Water (DHW)  Perform modeling simulations and calculations  Use an annual energy simulation program (SEEM) with a combination of engineering calculations  Compare results to base case using a weighted average to predict energy savings

4.  1344ft 2 – original bldg in 1 st Power Plan from 1982.  Single story over crawl space (or slab)  2688ft 2 – added to mix in late ‘80s  Like 1344, but over a conditioned basement  2200ft 2 – added in early ‘90s to address more complex designs  1.5 story split level with garage and bonus room (over crawl)  5000ft 2 – special case for 2009 to address large house size  conditioned basement plus 2 stories above grade  Weighting % for WA determined by census data and baseline stock assessments to create a representative snapshot of building population.  Covers multiple construction scenarios (basement, crawl, etc.)  Window areas determined from baseline surveys PrototypeWeight 134415% 220075% 26889% 50001%

5.  Typical Meteorological Year (TMY3)  From NREL  Three representative sites for Oregon: CityHDD65CDD65 Portland4187367 Redmond6583204 Medford4530601

6.  OR 2008 Energy Code:  Prescriptive requirements (Table N1101.1(1))  Which additional measure to use? ▪ Choice matters because not all additional measures save the same amount of energy.  Leads to slightly different base case comparison targets ▪ High efficiency HVAC assumed most likely (i.e. typical) ▪ With better market information, we could construct an energy baseline using a weighted average of all the additional measures  House infiltration – not specified in 2008 code. ▪ Average new house is ~6.5ACH50 but 25% of all houses >9ACH50. Where to set infiltration base?  Miscellaneous electric load (MEL) levels

7.  New (or more) additional efficiency measures to consider for code upgrade. ▪ Equipment efficiency improvements ▪ Duct sealing or interior duct placement ▪ High efficacy lighting ▪ Building shell (windows, walls, ceilings, floors) ▪ Water heater efficiency ▪ Building infiltration ▪ Solar PV (generation not conservation) ▪ Solar thermal for water heating (generation not conservation)

8.  SEEM – Simple Energy Enthalpy Model  Developed in the Northwest specifically for the NW ▪ Models ducts losses, heat pump behavior, and ground contact more accurately than other available simulation tools ▪ Models heating & cooling load correctly (for our climate)  Used in Northwest Power Plan  Inputs calibrated to match billing data  SEEM predicts the hardest part of whole house energy use: heating and cooling energy ▪ Calibration is important in order to ensure accuracy  Engineering calculations used for DHW, lighting, ventilation, appliance, and MELs. ▪ These calculations are also calibrated to match field data

9.  Lighting energy use. The number and type of bulbs in a house comes from regional survey data (NEEA).  Average values: ▪ 1 Incandescent ~65W ▪ 1 CFL ~17W ▪ On-time: 2 hours/day  Lighting use 2200ft 2 house, 50% CFLs 1766kWh/yr = 1.1(W/ft 2 ) x 2200(ft 2 ) x 2 (hrs/day) x 365(days/yr) / 1000(kW/W) % CFLsLPD (W/ft 2 ) 01.75 501.1 750.8 900.6

10.  DHW use based on 2.5 people per house using 22 gals/person/day  Hot water consumption baseline has held fairly constant in Ecotope studies from the 1980s to today  Presentations as ASHRAE summer meeting 2010 also reconfirmed base consumption  Hot water efficiency measures:  Upgraded equipment  Lower flow faucets and appliances  OR Electric Tank Code Base: 0.87 EF uses 4020 kWh/yr

11. thrms/yrkWh/yr 2006 Code 7497945 2009 Code 6136828  Typical modeled site-use energy consumption for a 2200ft 2 house with gas furnace and gas DHW  MELs consist of appliances and plug loads (~4000kWh/yr)  2009 Code compliance met with upgraded furnace

12.  Taking 66 inputs, SEEM calculates the building heating and cooling loads, including humidity effects, at hourly intervals to determine annual energy use.  SEEM accounts for:  Weather conditions using TMY data (1500 unique sites available) ▪ Including solar gains and humidity  Internal heat and moisture gains  Heat and moisture loss to buffer spaces through conduction and duct leakage  Heat loss to the exterior  Heat Pump COP 12

13.  SEEM accurately models both air temperature and mean radiant temperature  SEEM offers state of the art modeling of heat pumps and air- conditioners including thermostat setup penalty and heat pump controls  Empirically derived performance maps for HP and A/C include  Multiple equipment control strategy possibilities  Complete psychrometrics implementation includes  Water balance on all zones: attic, crawl, and conditioned space  User input for internal water gains  Calculation of latent cooling load 13

14.  SEEM accounts for duct losses and their impact on all zones/buffer spaces  SEEM calculates ground heat transfer to estimate the overall 3-dimensional U-value.  Slab-on-grade ▪ Full under slab insulation (interior insulation also modeled) ▪ Perimeter insulation with user determined depth  Crawl spaces, Unheated and Heated basements ▪ Allows different wall types for above and below grade components  Multi-level buildings are modeled with independent input of conditioned floor area, volume, footprint area, ceiling area, and external (i.e. cantilevered or over garage) floor area 14

15.  Under the hood  Uses input.csv file & output.csv file  On top - Excel spreadsheet integration  Contains input and output within one workbook  Easy to edit parameters  Flexible for analysis  Fully customizable ▪ User can create additional calculations for DHW, lighting, etc ▪ Easy to integrate with graphs or other tables  aa_copy_me_seem92.xls  Example: ex1-nwcities.xls 15

16. UATotal (Btu/hr F)calculated UATotal UA from house to outside and ground including air infiltration. HDD65 (°D)°Heating Degree Days Base 65Heating degree days base 65 for input climate CDD65 (°D)Cooling Degree Days Base 65Cooling degree days base 65 for input climate Pressure (atm)Site pressure in std atmospheresCan be used to correct for altitude effects on mass flow RoomHeatkWh (kWh)Annual house heating loadHeat which must be delivered to house (conditioned zone) EquipHeatkWh (kWh)Annual heating equipment outputHeat supplied by equipment into the duct system. The number includes the effects of duct losses and fan heat. Includes all auxheat. InHeatkWh (kWh)Annual heating equipment inputSite energy required to produce equipheat. Includes the effects of equip. eff., duct losses, and fan energy. Includes all auxheat. AuxHeatkWh (kWh)Annual electric strip heatUsed for heat pumps when compressor not meeting load FanHeatkWh (kWh)amount of energy used by the fanThis heat is included in equipheat. The fanheat is equal to the fan input power. FanHeathrs (hr)total fan run time in heating modeEquals the equipment runtime in heating mode. RoomCoolkWh (kWh)annual house cooling loadCool which must be delivered to house (conditioned zone) EquipCoolkWh (kWh)annual cooling equipment outputCool supplied by equipment into duct system. Includes the effects of duct losses and fan heat. InCoolkWh (kWh)annual cooling equipment inputSite energy required to produce equipcool. Includes effects of equip. eff., duct losses, and fan energy. QLatentkWh (kWh)annual latent load in cooling modeAmount of input energy used in cooling mode to meet latent load LatentPct %percent of cooling due to latent load AuxCoolkWh (1 or 0)auxiliary cooling#hrs cooling set point not met 16

17.  #1 input to get right in modeling  Qgains – internal heat gains (Btu/hr). Sources include: ▪ Lighting – can be a simple calc using LPD and assuming ~2 hrs per day annual use ▪ Appliances – depends on appliances in use ▪ People – numbers in ASHRAE Fundamentals ▪ Plug loads – largest unknown  Wgains – internal water gains (lbs/hr). Sources include: ▪ People, pets, showers, cooking, aquariums, etc.  Effects indoor RH and latent cooling load  Suggest 0 or 0.5 lbs/hr 17 INTERNAL GAINS: Lighting, Equipment, People, Appliances Descriptor: Single Family Town House 24 Unit Building Manufactured Home Floor Area (ft 2 ):135022002688500015001000 / unit92415682352 Lighting:Internal Gains (Btu/hr) 1.75 LPD (W/ft 2 ) 0% CFLs (1) 2165271331894207243448672199324863032 1.150% CFLs (2) 1940236427003288218944472183522072630 0.875% CFLs (3) 1853220725262829206742792176620852438 0.690% CFLs (4) 1783210223682553198041112171320152316 (1) Baseline (2) NW EnergyStar, OR Code, Proposed WA Code (3) OR EnergyStar (4) Full

18.  Example: ex3-gains.xls  Prototype: 2200 ft 2  Envelope: NWBOP1  Equipment: Gas Furnace AFUE 90  Explore impact of lighting levels on gains and energy use in Spokane  Lighting levels: All incandescent, 50% CFLs, 75% CFLs, 90% CFLs 18

19.  Examples:  Puget Sound Energy study - produced Access database with ~250,000 entries  Power Council 6 th Power Plan Residential Sector ~ 350,000 runs  WA State Energy Code Update ~60,000 runs  Custom data processing tools written for each application  Includes calculations for lighting, heat system efficiency, hot water, fan energy, etc.  Example: current OR Energy Code Modeling