Simple Zero Energy Houses

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Simple Zero Energy Houses

• Jeff Christian, Oak Ridge National Laboratory
• Third U.S. Conference on Peak Oil and Community
  Solutions
• September 23, 2006

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A few thoughts to start with

• Seek simple, decent, and sufficient house plan
• Maximum energy efficiency (50)
• Little bit of solar (2kW)
• Friendly electric utility (Green Power)
• Offer educational opportunity to your community
  (National Solar Tour October 7, 2006)

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Habitat for Humanity Loudon County TN Harmony
Heights

• ZEH2
• ZEH3
• ZEH4

3800 HDD_at_65 oF

• ZEH1
• Base House

South
ZEH5 finished Sept. 2005
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Grid connected PV and Tennessee Valley Authority
Green Power Partner

• Residential retail rate 0.07/kWh
• Sells green power for0.10/kWh)
• Buys solar at 0.15/kWh for 10 years

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First four houses to sell solar power to largest
public electric utility in U.S.

•  

• Annual measured heating cost ZEH1 100, ZEH3
  39
• Cooling ZEH1 80, ZEH4 69
• Domestic hot water ZEH1 100, ZEH2 65
• Space heating and cooling energy 0.40 to 0.50/
  day
• Solar credits 0.82 to 0.93 / day
• Net off site total energy 0.75 to 1.00 / day

ZEH1 built in 2002
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August 2004 total energy bill 14.52
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Natural Air Change per Hour
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Total VOC measurement results for nZEH and
conventional houses
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All 5 houses constructed with SIPS
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Consider geothermal Heat Pump

• ZEH1- Carrier SEER 13, DC fan
• ZEH2- Carrier 2 speed compressor, 14 SEER, DC fan
• ZEH3- American Geothermal DX, DC fan
• ZEH4- Lennox 17 SEER, two speed compressor, DC
  fan
• ZEH5- Water Furnace Geothermal water loop, DC fan

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Ducts inside conditioned space (35 energy
savings)
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1100-2600 ft2 Efficient Floor Plans with kitchen,
bath and laundry clustered
Rescor
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Hot Water distribution losses average 20
gallons/day, that is a 30 savings in hot water
energy and water usage
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ZEH4 all premanufactured panels
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ZEH4 Performance

• This all electric house used 27 kWhr/day
• Other loads averaged 15 kwhr/day
• Solar AC generation 7.2 kWhr/day
• On site power 27 of total energy
• If you cut other loads in half on-site power - 37

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ZEH4 measured energy use, August 2004 through
July 2005
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To get to zero work with your electric utility to
find their ZEH benefits, like peak load savings,
off peak revenue

• Total annual energy usage 9837 kWh, -669.
• Total solar AC produced 2627 kWh, _at_0.15, 394
• If Utility incentive was 0.255/solar kWh 669
• Than net energy cost 0

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ZEH reduces Winter Peak Load by 50
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ZEH reduces summer peak loads by 40
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ZEH 3
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(No Transcript)
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ZEH3 measured energy use, March 2004 through
February 2005
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Using geothermal heat on ZEH4

• ZEH3 used only 569 kWh
• ZEH4 used 1711 kWh
• Savings with geothermal 1142 kWh
• Reduces total load from 9837 to 8695
• 8695 X 0.068 2627 X (Utility green power buy)
• Than if utility green power buy back 0.22/kWh,
• Homeowner net energy cost 0.00
• Zero net energy cost a big marketing feature and
  a huge stepping stone toward true net zero energy
  housing

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ZEH4 Other load goes to Sufficient Load (cut
in half) plus geothermal

• If other load cut in half -2649 kWh
• Now total load 6047 kWh
• of on-site generation 43
• 6047 kWh X 0.068/kWh 2627 solar kWh X (Utility
  green power buy)
• With utility green power buyback 0.15.6/kWh,
  net homeowner energy cost 0

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Construction cost of test houses 15 and the base
frame house
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ZEH5 an unoccupied test house for two year period

• Fiberglass board exterior insulation on
  foundation
• Geothermal
• 6 in SIP walls, R-36 roof
• Rescor
• Dehumidifing HPWH

in construction Sept 05
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Geothermal loop utilized existing excavations
Sewer trench
Water trench
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ZEH5 a ZEH Research Facility ready for
partnerships
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Partnering to find best components and mass
purchase for this house
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Summary

• Build a small high performance - all electric -
  building science designed driven house
• SIPS with housewrap and drainage plane or
  equivalent
• High Performance Windows (U-value 0.34, SHGF
  0.35)
• Air tight
• Ducts inside
• Raised metal seam roof (no roof penetrations)
• Heat Pump Water Heater
• Geothermal (horizontal coil in existing open
  ditches)
• Exterior Foundation insulation
• Rescor wall
• ASHRAE 62.2 mechanical ventilation
• 2 kW PV Solar system

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Add

• An electric utility that offers a Green Power
  Program which buys and sells solar kwh (peak load
  savings, increase off peak revenue)
• Work with low income housing provider to keep
  construction cost down
• Link house with Educational opportunities

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Existing House ZEH retrofit Stratgies

• Assess what you have, do an energy audit,
  consider a HERS
• Generate a prioritized list of all the energy
  saving opportunities, use an auditing software
  program
• Add solar water heating and gridtie solar PV to
  your prioritized list
• Determine your budget and work down your list

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The Weatherization Assistant(WA)

• Developed by Michael Gettings
• Oak Ridge National Laboratory

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The Weatherization Assistant

• Started in 1976 to assist low-income families
  afford energy expenses
• From 1973 to 1976 oil prices increased from
  13/barrel to 21/barrel
• Todays price is 60-70/barrel
• Generates customized prioritized list of retrofit
  measures

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Weatherization Assistant is used in

• all 50 states through approximately 900 local
  agencies
• 105,000 homes in 2006

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The Weatherization Assistant

• Developed for the DOE Weatherization Assistance
  Program
• Computer-based energy efficiency measure
  selection tools for single-family and
  manufactured homes
• Attributed with saving 70 million over
  life-time of single years retrofits

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Whole House Approach energy system with
interdependent parts

• Consider interaction between envelope, equipment,
  distribution and other factors
• Recognize that features of one component can
  affect others
• Measures ranked based on economic criteria using
  interacted savings

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Whole House Approach
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Percent of Total Energy Costs by End-Use in
Households up to 150 Poverty
The Energy Usage and Needs of Low-Income
Households
Economic Opportunity Research Institute
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Percent of Heating/Cooling Loads by Source
Cooling Load
Heating Load
Sensible Infiltration 4
Infiltration Humidity 25
Ceilings 15
Infiltration 39
Ceilings 21
Walls 15
Internal Humidity 13
Walls 12
Doors 2
Windows 23
Windows 23
Floors 9
Doors 3
Resource and Energy Efficient Construction
Southface Energy Institute
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Standard Insulation Measures

• Attics
• Level of insulation (R-level, cavities)
• Type of insulation (fiberglass, cellulose,
  board)
• Finished attics (gables, dormers, etc.)
• Wall mode of installation (drill and plug, from
  inside, etc.)
• Foundation
• Floors
• Walls
• Rim Joist

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Percent of Heating/Cooling Loads by Source
Cooling Load
Heating Load
Sensible Infiltration 4
Infiltration Humidity 25
Ceilings 15
Infiltration 39
Ceilings 21
Walls 15
Internal Humidity 13
Walls 12
Doors 2
Windows 23
Windows 23
Floors 9
Doors 3
Resource and Energy Efficient Construction
Southface Energy Institute
44
Window Treatments
Each approach may have a different effect on

• Infiltration
• Conduction
• Solar
• Comfort
• Value added to home

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Shading / Solar Measures

• Windows
• Shade screens
• Films
• Awnings
• Interior shading (blinds, drapes, etc.)
• Roofs
• White roof coating (manufactured homes)
• Factors
• Effect on heating and cooling loads opposite
• Time of use
• Occupant dependent

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Window Treatments
What is the most cost effective approach?

• Caulk and weatherstrip
• Is window repairable?
• Will repairs persist?
• Add storm
• What is the effect on the primary window?
• Are there egress codes to satisfy?
• Replace
• Should low-e / multi-paned window be used?

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Window Treatments

• Potential Impacts of treatments estimated using
  laboratory experiments
• Used actual windows cut from existing homes
• Measured change of conduction and air leakage
  before and after treatments
• Results used in NEAT to guide auditors in window
  retrofit decisions

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Percent of Heating/Cooling Loads by Source
Cooling Load
Heating Load
Sensible Infiltration 4
Infiltration Humidity 25
Ceilings 15
Infiltration 39
Ceilings 21
Walls 15
Internal Humidity 13
Walls 12
Doors 2
Windows 23
Windows 23
Floors 9
Doors 3
Resource and Energy Efficient Construction
Southface Energy Institute
49
Infiltration Reduction

• WA evaluates success of blower-door directed
  infiltration reduction efforts

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Duct Sealing

• Typically ducts are only 50 - 75 efficient
• Blower-door / duct blower procedures for testing
  exist
• ASHRAE Draft Standard 152P used to translate
  measured duct leakage into duct delivery
  efficiency

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Duct Sealing
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Duct Leakage Measurements
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Weatherization AssistantDuct Input
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Equipment Efficiency Measures

• Furnace / AC replacement
• Standard / High efficiency
• System tune-up
• Setback thermostats

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Percent of Total Energy Costs by End-Use in
Households up to 150 Poverty
The Energy Usage and Needs of Low-Income
Households
Economic Opportunity Research Institute
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Appliances
Refrigerator Replacement

• Direct replacement of older models cost-effective
• Older units can consume up to 2100 kWh/yr
• New units consuming 450 kWh/yr easy to find
  costing 400
• Units consuming 350 kWh/yr under design
• Economics improve if replacing at end of older
  units lifetime

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Appliance Metering
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Refrigerator Data Base (AHAM)
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Refrigerator Data Base (AHAM)
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Where Does the Hot Water Go?
Source Rocky Mountain Institute Website
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Water Heating Measures Evaluated

• Gas / electric / propane water heater wrap
• Pipe insulation
• Low-flow showerheads
• Water heater replacement
• Heat pump water heater replacing electric unit

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Appliances
High-Efficiency Clothes Washers

• Use 50 (65) less energy
• Require 30 (40) less water
• Seventeen states now have high-efficiency clothes
  washer programs
• Most well known manufacturers produce models
• Still need utility/manufacturer rebates to obtain
  cost-effectiveness from energy alone

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Lighting
Compact Fluorescent Lamps

• Considered cost-effective if replacing
  incandescent lamps on 4 or more hours per day
• Fluorescent lamps have 10 times the life
  expectancy of incandescent lamps
• Must match lighting level provided by
  incandescents replaced

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Sample NEAT Output
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Sample NEAT Output
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Thank you!

• Jeff Christian
• ChristianJE_at_ORNL.gov