Presentation of LBNL Follow-up A by fjwuxn

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									Review of Impacts of NFRC Board
Committee Proposed Changes for
Residential Modeling Assumptions

              Joe Huang,
     Robin Mitchell, Steve Selkowitz
  Lawrence Berkeley National Laboratory

NFRC Subcommittee & Task Group Meeting
            Ft. Worth TX
           8 January 2004
     NFRC Board Committee Proposed
      Changes to RESFEN Modeling
             Assumptions
1.   Change prototypical building size and type from a
     2000 ft2 one-story to a 2400 ft2 two-story house
2.   change envelope levels from 1993 MEC to 2003
     IECC
3.   change the shading effect of window drapes from
     0.80 summer / 0.90 winter to a constant value of
     (0.9 – 0.25 * SHGC)
4.   lower the cooling thermostat from 78ºF to 75ºF
5.   increase house internal load from 56 to 92 kBtu/day
6.   eliminate the modeling of natural ventilation
       Background on Modeling
     Assumptions Used in RESFEN
•   Extension of residential modeling work done for
    DOE voluntary residential energy standards (1982-
    1987), ASHRAE SP-53 (1986-1988) and 90.2 (1987-
    1990)
•   Assumptions discussed and reviewed by AEP Task
    Group during development of RESFEN (1996-1998)
    and for simulations done for NFRC 900 (1998 - )
•   Results compared to average reported average
    energy consumptions from RECS.
     How Do We Know If We Have the
          “Correct” Answers?
•   Solid data on average residential operating conditions
    are often not available or sporadic in nature.
•   Most assumptions based on available literature, work of
    others, estimates using first principles, and
    “engineering judgement”.
•   Even when specific modeling assumptions taken
    separately appear to be “reasonable”, it is necessary to
    check that the interactive sum of all assumptions give
    results that “make sense”.
•   The final objective should be to have results that
    approximate the measured energy use of the nations
    residential stock, as reported in reports such as EIA’s
    Residential Energy Consumption Survey
    (RECS).
Analysis of Impact of Proposed Modeling
 Changes on Simulated Energy Usage
 • To analyze the impact of these proposed modeling
      changes, sensitivity studies were done for the six
      proposed changes on a new vintage prototypical
      house in the following eight US climates :
       Minneapolis             Washington
       Denver                  Seattle
       Los Angeles Airport     Los Angeles Downtown
       Miami                   Phoenix
  •   Sensitivity studies were done separately for each of
      the six proposed changes, concluding with a
      combined case with all proposed changes
      implemented together.
                                                    Source Energy (kBtu/year-ft 2)




                                                0
                                                    10
                                                          20
                                                                 30
                                                                        40
                                                                               50
                                                                                     60


                                  Minneapolis




                                      Denver




                                  Washington




                                      Seattle




                                  Los Angeles




                                      CTZ09C




                                       Miami
ΔHeating -0.1% , ΔCooling +5.6%




                                     Phoenix
                                                                                          Parameter: Internal Shading Schedule
                                                 Source Energy (kBtu/year-ft 2 )




                                                     10
                                                          20
                                                               30
                                                                    40
                                                                          50
                                                                               60




                                                 0
                                   Minneapolis



                                       Denver



                                   Washington



                                       Seattle


                                        Los
                                      Angeles


                                      CTZ09C



                                        Miami
ΔHeating -12.9% , ΔCooling +7.1%
                                                                                    Parameter: House Type/Size




                                      Phoenix
Building Floor Area Data from RECS
Cooled Floorspace
• < 500 – 1,499: 43.8 million households, 44% of
  total cooled households
• 1,500 – 2,499: 20.5 million households, 25% of
  total cooled households
• 2,500 – 4,000 or more: 16.5 million households,
  20% of total cooled households
Comment: this data argues for a typical house closer to
 2,000 square feet rather than 2,500 square feet as the
 default
   House Type Constructed by Year
  source: http://www.census.gov/const/C25Ann/sfforsalestories.pdf
                                        600
                                                 1 story
                                                 1 story
                                        500
                                                 2 stories or more
       Floor area constructed by year



                                                 Split level
                                        400


                                        300


                                        200


                                        100


                                         0

                                          1973      1987             2002
Comment: the stock is relatively evenly split between 1 and 2 story
construction, with construction since the mid-80s shifting to 2 story.
A single model is unlikely to accurately represent the stock although
the impact of this alone on relative energy use is not large.
                                                 Source Energy (kBtu/year-ft 2)




                                                 0
                                                     10
                                                          20
                                                               30
                                                                    40
                                                                         50
                                                                              60
                                                                                   70
                                   Minneapolis




                                       Denver




                                   Washington




                                       Seattle




                                   Los_Angeles




                                       CTZ09C
                                                                                                Requirements




                                        Miami
ΔHeating +22.1% , ΔCooling -6.5%




                                      Phoenix
                                                                                        Parameter: IECC 2003 Envelope
Status of Energy Code Adoption by State

 •   Summary from the Status of State Energy Codes,
     “BUILDING CODES ASSISTANCE PROJECT
     NEWSLETTER”, September/October 2003, can be
     found on their website
     http://www.bcap-energy.org/newsletter 51.htm

 •   48% (24 states) have or are going to have 2000 IECC
 •   52% (26 states) have earlier codes or no codes
                                                      Source Energy (kBtu/year-ft 2)




                                                  0
                                                       10
                                                             20
                                                                   30
                                                                          40
                                                                                50
                                                                                       60


                                    Minneapolis




                                        Denver




                                    Washington




                                        Seattle




                                    Los Angeles




                                        CTZ09C




                                         Miami
                                                                                            Parameter: Internal Gains




ΔHeating -16.0% , ΔCooling +24.8%




                                       Phoenix
Appendix D from 1987 LBNL Technical
Report for DOE Voluntary Residential
         Energy Standards
                                  Annual
  Use               Saturation                   %       Sensible       Latent
                                  Energy
                                              Indoors     Load           Load
                                   Use
 New                   1.0       1125 kWh      100       1125 kWh         0
 Refrigerator
 Old Refrigerator      0.15       1600 kWh      15        35 kWh          0
 Freezer               0.45        950 kWh      50       214 kWh          0
 Range gas             0.19       60 therms    100       805 kWh       415 kWh
        electric       0.78       1200 kWh
 Hot Water gas         0.37      275 therms     50       940 kWh       140 kWh
                       0.59       1285 kWh     100
 electric
 Dryer electric        0.70      900 kWh        10         63 kWh         0
        gas            0.08      500 kWh        10         4 kWh
 Television            1.0        100 W        100        200 kWh         0
 Miscellaneous         1.0           -         100        300 kWh         0
                                          2
 Lighting              1.0       1 kWh/ft       90       1386 kWh         0
 People                3.2           -           -        930 kWh      735 kWh

 Totals                 -            -           -      6000 kWh/yr   1290 kWh/yr
                                                     Source Energy (kBtu/year-ft 2)




                                                 0
                                                     10
                                                           20
                                                                  30
                                                                         40
                                                                                50
                                                                                      60
                                   Minneapolis




                                       Denver




                                   Washington




                                       Seattle




                                   Los Angeles




                                       CTZ09C




                                        Miami
ΔHeating +1.6% , ΔCooling +40.0%
                                                                                           Parameter: Cooling Setpoint




                                      Phoenix
Average Interior Temperature of 170 homes
  in Central Florida from 6/1/99 to 9/30/99
                                                                                                        FPC0005INTAIR




                  Average 78.2 F




"Research Highlights from a Large Scale Residential Monitoring Study in a Hot Climate"
 Presented at the International Symposium on Highly Efficient Use of Energy and Reduction of its Envir.Impact
 Japan Society for the Promotion of Science Research for the Future Program, Osaka, JPN, Jan 2002
                                                    Source Energy (kBtu/year-ft 2)




                                                0
                                                    10
                                                          20
                                                                 30
                                                                        40
                                                                               50
                                                                                     60

                                  Minneapolis




                                      Denver




                                  Washington




                                      Seattle




                                  Los Angeles




                                      CTZ09C




                                       Miami
ΔHeating -0.2% , ΔCooling +5.7%




                                     Phoenix
                                                                                          Parameter: Natural Ventilation
RECS Information on Occupancy Patterns

  Someone home all day (Table CE3-6.2u):
     Y Yes: 49% (39.9 million households / 80.8
      million total households)
     N No/Don’t Know: 51% (40.8 million
      households / 80.8 million total households)

  Comment: These data were used to support the original
    natural ventilation strategy and the interior moveable shade
    strategy, since at least half the time someone is home to
    operate these things
                                                    Parameter: All 6 Proposed
                                                     Modifications Combined
                                 60
Source Energy (kBtu/year-ft 2)




                                 50


                                 40


                                 30

                                 20


                                 10

                                 0




                                                                                                     CTZ09C
                                                                                       Los_Angeles
                                      Minneapolis




                                                                Washington




                                                                                                              Miami




                                                                                                                      Phoenix
                                                       Denver




                                                                             Seattle




                                                    ΔHeating -14.8% , ΔCooling +91.5%
                                Comparison of Cooling Electricity
                               Calculated by RESFEN and Proposed
                                 Modified Assumptions to RECS
                               14000
Cooling Electricity (kWh/yr)




                               12000

                               10000

                               8000

                               6000                                              2001 RECS
                                                                                 RESFEN New
                               4000
                                                                                 RESFEN Old
                               2000                                              Proposed New
                                                                                 Proposed Old (?)
                                  0
                                       New York   California   Texas   Florida
Comparison of Heating Fuel Calculated
 by RESFEN and Proposed Modified
       Assumptions to RECS
                           140

                           120
Heating Fuel (MBTU/year)




                           100

                           80

                           60                                              2001 RECS
                                                                           RESFEN New
                           40
                                                                           RESFEN Old
                           20                                              Proposed New
                                                                           Proposed Old (?)
                            0
                                 New York   California   Texas   Florida

								
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