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2011 09-16 eeba - nahbrc-ip zeh
 

2011 09-16 eeba - nahbrc-ip zeh

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  • Buildings consume about 1/3 of energy in U.S.Over 25% of energy $$ is for homesAverage homeowner could cut energy bill by half through EEReduce dependence on fossil fuelsReduce pollution and CO2 production
  • resulting in a net-zero energy consumption for the home over the year.
  • The PV system that meets the estimated annual use is about 5,700 watts - requiring just over 500 square feet of south facing roof area. The PV system is estimated to produce about 8,266 kWh annually.
  • Solar hot water systems provide a pre-heat for domestic hot water and space heating systems.

2011 09-16 eeba - nahbrc-ip zeh 2011 09-16 eeba - nahbrc-ip zeh Presentation Transcript

  • Net Zero Energy Case Study Amber Wood Manager, Energy Programs EEBA Conference 2011 September 16, 2011Driving Innovation in Housing Technology
  • NAHB Research Center Upper Marlboro, MD Housing R&D and laboratory testing  Promote innovation  Enhancing quality & affordability  Promoting high standards for the building industry 2
  • Building America Private/public R&D partnership sponsored by DOE Energy-efficient solutions for new and existing housing  Technologies/Systems  Whole-House Test Homes  Quality Processes
  • Maryland ZEH Project Why ZEH?4
  • What is ZEH?Efficient Efficient RenewableEnvelope Equipment energy systems Annually producing as much energy as consumed
  • ZEH DisclaimerA Zero Energy Home is NOT:  Zero energy consumption  Utility independent  Energy rationed  Energy unlimited 6
  • The Basics Hathaway home, Purcellville, VA. NREL photo archive1. Decrease total energy use2. Produce energy from renewable sources 7
  • An Energy Efficient HomeHouse Shell:More wall and roof insulation, Water Heating:low-e windows, insulated Solar preheat,foundation, overhangs, efficient delivery,passive solar orientation low-flow fixturesAir-sealing: Lighting:Seal vents, holes and Fluorescent,gaps through walls and daylightingroof Appliances:Heating & Cooling ENERGY STAR®Equipment: LabelHigh Efficiency,programmablethermostat, sealedducts, ventilation Plug & Small Appliances: Individual homeowner’s 8 choice to decrease use
  • Effect of Efficiency Upgrades 12,000 120% 110% 10,000 100% 90%Annual Consumption (kWh) Percent Reduction in Use 8,000 80% 70% 6,000 60% 50% 4,000 40% 30% 2,000 20% 10% 0 0% Heating Cooling Water Heating Ventilation Air All Other Loads Primary Energy Category Base House Net-Zero Design Reduction in Use 9
  • Example ZEH Energy Use Baltimore, MD Base House Percent Net-Zero Annual Annual Percent of Energy End Use of Consumption Consumption Total (%) Total (%) (kWh) (kWh)Heating 12,749 47 2,110 26Cooling 5,100 19 850 11Water Heating 3,627 13 167 2Ventilation Air 0 0 175 2All Other Loads 5,730 21 4,833 59Annual Consumption 27,206 100 8,135 100 PV System  5,700 W  500 sqft area  Produce 8,266 kWh 10
  • ZEH Approaches ZEHDetails InvolvingBuilder, Trades,Government, etc. 11
  • Current ZEH Experience Over 50% minimum reduction in total energy  Typically 50 – 70% Net-zero electric bill Gas offset unavailable 12
  • Solar Water Heating System 13
  • Solar Electric (PV) Systems Convert sun energy to electricity  Operate daily  Output varies PV Systems are ZEH remodel in NJ, courtesy of Bill Asdal  Available,  Reliable, &  Low maintenance  Quiet 14
  • Utility Connection 15
  • ZEH Utility Requirements  Utility must “net-meter”: credit for electricity fed back to the utility  Utility must “settle” credit not less than once a year  Utility must be ON to have PV power 16
  • Armory Park del Sol A Historic Solar CommunityJohn Wesley Miller Companies And NAHB Research Center
  • Armory Park del Sol Urban in-fill  Former site of Southern Pacific RR executive homes  Utilization of existing infrastructure Downtown Tucson  Rio Nuevo Project  Walking distance – downtown & University of Arizona  Cultural activities, arts & music  Tucson Convention Center  Theatre, Symphony, concerts  Artist galleries  Museums
  • Armory Park del Sol 14 acre subdivision Urban in-fill in downtownTucson Single family homes Awards for energy efficiencyconstruction Utility collaboration
  • Armory Park delSol
  • Armory Park delSol 14 acre subdivision  Purchased land in 1999  99 lots  Construction started 2000 Historic Armory Park/ Armory Park del Sol  Designs blend with area tradition  Neighborhood has embraced project  Local property values much higher
  • Armory Park del Sol Single family homes  New technology/ construction methods  Traditional Southwestern exterior design  Metal framing  Termite-proof  Concrete construction  Thermal mass  Significant energy savings
  • Armory Park del Sol Energy efficiency construction  Thermal mass wall – exterior insulation  Insulation through slab edge  Raised heel truss, R-38 ceiling  Dual-pane, Low E & Low Solar Heat Gain windows  Ducts in conditioned space  14 SEER heat pump  HVAC system design using Manual J  Optimized (reduced) duct runs  Return air pathway from each room  Passive ventilation system
  • Armory Park delSol Solar Electric Technology  1.5 kW Photovoltaic (PV) system minimum  Garage roof mount (parapet wall)  Utility approved components & systems; annual utility inspection
  • Armory Park del Sol Solar System Attributes  One Subcontractor (The Solar Store) installed all systems  Subsystems & components from major U.S. or multi-national firms  BP PV Modules  Trace Inverters  System meets TEP SunShare requirements (ACC approved)  Compliance  IEEE  National Electric Code  TEP Service Requirements Book
  • Armory Park del Sol Single family homes  Information age design  Minimum 3 telecom ports  Digital Satellite Service  CAT5e wiring  Pre-wired for fiber optics  Security system  Central vacuum
  • Armory Park del Sol Utility collaboration  Tucson Electric Power 5 year A/C guarantee  TEP inspects each home during construction  Guarantee qualifies Armory Park del Sol for reduced residential utility rates  Guarantees heating & cooling portion of annual bill
  • Armory Park delSol Utility Collaboration / Solar Electric System  State & federal tax credits  Homeowner qualifies for TEP cash rebates  Output offsets highest Time-of-Use rate  TEP inspects solar electric system annually  City permit fee credit up to $1,000
  • Armory Park delSol
  • Armory Park delSol
  • Armory Park delSolSolar Energy Homes in Downtown Tucson An Award Winning Community!  SAHBA Builder of the Year, 2003  City of Tucson Most Energy Efficient Builder, 2003  Sonoran Institute Livable Community Award, 2005  NAHB Builder of the Year Award Winner, 2005  Metropolitan Pima Alliance Common Ground Award, 2006
  • Armory Park del Sol APdS Standard Homes  Predicted to use less than half the energy of a typical regional home
  • Net Zero Energy Home Project
  • Tucson Zero Energy Home Construction 35
  • Zero Energy Home at APdS  Natural extension of work at APdS  Engineering work funded by DOE through NREL  Goal of net-zero annual energy use  Started with clean sheet of paper 3
  • Zero Energy Home Design TeamNAHB Research Center, Inc. Armory Park Del Sol Project Management Build Design Support Define Constraints Monitoring Consumer Education Project Summary Information Dissemination Consumer Information Feedback Solar Store Manufacturers Design Design Support Manufacturer Contact Product Specification Solar Components Installation Requirements
  • Zero Energy Home Construction Features Concrete walls with 2” polyiso R-41 attic U-0.32, SHGC-0.35 windows SEER 18 AC Combined solar (128 sf) space and water heating system with tankless backup 4.2 kW PV array PEX piping (with some copper) Fluorescent lighting throughout Outdoor living spaces Ceiling fans without light kits Energy Star appliances 38
  • Masonry Walls
  • 2” Polystyrene
  • Radiant Roof Decking
  • Window & Porch Overhangs
  • Air Admittance Valves
  • Systems in Conditioned Space
  • 4 kW PV System
  • 46
  • Armory Park delSol Zero Energy Home 1  Now averaging about $10/mo (including $5.28 monthly base fee)  Average 23 kWh/day Total Average Energy Use Tucson ZEH at Armory Park del Sol Monthly Total Energy Use and Cost 1,800 $90 Modifications to solar thermal system 1,600 (+ values = House Use; - Values = Utility Feedback) complete $80 Electric Energy, kWh; Solar Insolation, kWh/m 2 1,400 $70 1,200 $60 Monthly Energy Cost 1,000 $50 800 $40 600 $30 400 $20 200 $10 0 $0 -200 -$10 Values less than zero indicate sell-back to the utility -400 -$20 Apr-04 Apr-05 Apr-06 Aug-04 Aug-05 Aug-06 Oct-03 Dec-03 Sep-04 Dec-04 Sep-05 Jan-04 Feb-04 Jun-04 Jul-04 Oct-04 Jan-05 Feb-05 Jun-05 Jul-05 Oct-05 Dec-05 Jan-06 Feb-06 Jun-06 Jul-06 May-04 May-05 May-06 Nov-03 Nov-04 Nov-05 Mar-04 Mar-05 Mar-06 Energy Cost Utility Supply PV Supply PV Insolation
  • Tucson ZEHData from 9/1/05 to 8/31/06 A/C Compressor, kWh, 1,847Other, kWh, 3,536 Utility Supply, kWh, 1158, Blower, kWh, 663 14% PV Supply, kWh, 7209, 86% Demand Water Heater, kWh, 1,040 Refrigerator, kWh, 631 Lights, kWh, 651
  • ZEH 1st Year Monitoring
  • ZEH OccupiedPeriod Monitoring
  • ZEH Monitoring Results
  • Year 1 ZEH Monitoring Results
  • ZEH Monitoring Results Electric Demand
  • ZEH Monitoring Results Electric Demand (w/o Dmd. Heat) 54
  • ZEH Monitoring Results Cooling Stage Operation5° Decrease in T’stat setpoint10° Rise in average ambient T1.86 kWh/day to 17.3 kWh/day
  • ZEH Monitoring ResultsSolar Thermal - Losses
  • Solar Thermal System• 210 gallon non-pressurized storage tank• 18 kW demand heater• 128 sf collector area 57
  • Solar Thermal Heating Summary Table 1. Summary of Daily Solar Thermal System Performance Average Min Max Insolation on Solar Thermal Array, 6.15 0.63 8.38 kWh/day Storage Tank Temperature, deg F 129.5 94.1 159.9 Hot Water Usage, gallons per day 62.4 33.8 122.8 Domestic Hot Water Energy Use, 23,750 10,858 46,572 Btu/day Solar Thermal Collector Production 56,400 0.0 104,000 (Btu/day) Solar Thermal Collector Efficiency 22.8% 6.0% 35.2% (days > 5,000 Btu production) The solar thermal system did not perform as expected. The average thermal energy collected during the heating season was much lower than the anticipated 80,000 to 90,000 Btu/day. If the system had performed as anticipated, the average daily heating and water heating load of 70,800 Btu/day could easily have been met by solar energy. Further investigation is needed to determine why the collector system is not performing as designed.3rd Quarterly Report 58
  • Solar Thermal Heating Summary Table 1. Summary of ZEH Heating Season Performance Measured Results Simulated Results Heating Period (November 1 – March 31) 151 days* HDD (November – March) 1,084 1,412 Ambient Temperature (average) 58.1 °F 55.3 °F Average Daily Minimum Temperature, °F 44 °F 42 °F Average Indoor Air Temperature** 73.6 °F 73.3 Indoor Thermostat Set Point, °F 72 72 Heating Energy Used, million Btu 7.105 4.637 Domestic Hot Water Energy Use, million Btu 3.586 Solar Energy Collected, million Btu 8.512 Demand Water Heater Supply, million Btu 6.257 System Losses, million Btu 4.079 Proportion of Heating Energy Supplied by Solar 60% Daily Average Heating Energy Use, Btu/day 47,050 30,700 Daily Average Thermal Load (heat and DHW), Btu/day 70,800 Average Daily Solar Energy Collected, Btu/day 56,370 (80,000-90,000 per design specs) *excluding 1 day of cooling (12/6); **Average at Thermostat3rd Quarterly Report 59
  • ZEH Monitoring ResultsHot Water Storage - Summer
  • ZEH Monitoring ResultsHot Water Storage - Winter
  • ZEH Monitoring ResultsInverter-Demand Heater Compatibility
  • ZEH Monitoring ResultsThermal Energy Supply/Use
  • ZEH Monitoring ResultsThermal Energy Supply/Use
  • ZEH Monitoring ResultsPV System Comparison
  • ZEH Monitoring Results PV System Output
  • ZEH Monitoring Results 1st Year PV System OutputPV system output = 7323 kWh (32°, 0° azimuth)Solar Input = 2370 kWh/m2 (6.49 sun-hours/day)Average AC Array Size = 3100 WTEP PTC rating for BP4200 dc = 3112 WTEP Average Annual Supply = 6300 kWh (17.3 kWh/day)Running Annual Average = 19.5 kWh/day
  • ZEH Monitoring ResultsThermal System Output
  • Plug Loads The big challenge… 69
  • Energy Simulation Summary Annual Electrical Consumption Description Cooling Heating Fan DHW Lighting Appl/Othr Total (kWh/yr) (kWh/yr) (kWh/yr) (kWh/yr) (kWh/yr) (kWh/yr) (kWh/yr)JWM Standard * 3,568 621 772 1,855 1,873 3,687 12,376ZEH As-Built ** 2,207 200 430 158 779 3,072 6,846TucsonStandard*** 6,770 669 1,229 4,064 1,873 3,687 18,292*(includes passive SDHW)**(Option A+B+C+D+E w/ R41 ceiling instead of R43)***Light Frame, R19 ceiling, 10 SEER, double pane wood frame windowsOccupied Use To Date :Demand Heater = 1,918 kWh, Lighting = 640 kWh, Other = 3,116 kWhTotal Use to Date = 6,406 kWh (26.3 kWh/day)Estimated Daily = 18.8 kWh 70
  • Lighting Energy Heating season lighting  Annual DOE energy estimated residential  2.4 kWh/day average lighting use  1.4 - 5.6 kWh/day range  1444 kWh average Simulation lighting  164 watts average estimates  Tucson ZEH design  Interior 0.13 w/ft2  100 watts average  Exterior 0.04 w/ft2 Average winter lighting energy use  0.06 w/ft2 for both 71
  • Tucson Lessons Learned  Project Success, Builder interest  PV system  Utility interest prime  Knowledgeable installer  Inverter compatibility problems (new)  Solar Aesthetics  Even with flat roofs  Solar thermal system performance  Temperature limitations  Controller  Losses 72
  • Tucson Lessons Learned Integration of HVAC & thermal system  Simple design/connections Space and access for thermal storage Thermal mass  Winter penalties? Air admittance valves  Manufacturer design required  Plumber reticence  Work 73
  • Tucson Lessons Learned PEX plumbing  Plastic material questioned  Negative history  Different installation method Lighting  Whole-house permanent fluorescent lighting options NOT mainstream  Cost is very high Plug loads 74
  • Recommendations Continued monitoring Solar thermal system design Thermal mass analysis Resolve inverter/heater compatibility Design for additional ZEH at Armory Park Integration of mechanical systems in conditioned space 75
  • Recommendations Develop homeowner information Identify values of ZEH Utility flat-rate billing (TOU better) Identify Repeatability  Would this house be built again??? Continue On With ZEH 76
  • Armory Park delSol Zero Energy Home 2 - Utility Savings  PV system cost benefit offsets utility-supplied energy
  • Questions? 78
  • Thank You! Amber Wood NAHB Research Center Manager, Energy Programs 400 Prince George’s Blvd  Upper Marlboro, MD 20774 (direct) 301.430.6309  (fax) 301.430.6180 www.nahbrc.comDriving Innovation in Housing Technology