Time Dependent Valuation TDV for Energy Standards

1
Time Dependent Valuation (TDV)for Energy
Standards

• Statewide Codes Standards ProgramPrepared for
  CEC Workshop April 2, 2002Presentation by
  PGE/HMG/E3/Eley/BSG

2
TDV Project History

• 1998-99 CEC/PGE Study Dollar-Based
  Performance Standards
• 1999-2001 PGE/SCE/SoCalGas further development
  of Time Dependent Valuation
• TDV Cookbook - economics methodology
• Engineering model enhancement
• Demonstrations of compliance outcomes
• Complete present proposal to CEC

3
TDV Project Team

• CEC staff - advise and comment
• PGE - development lead
• SCE SoCalGas - support, review, advise
• Consultant team - lead by HMG
• Economics E3
• Engineering Eley, BSG
• Other stakeholders consulted CBIA, NRDC, public
  workshop

4
TDV Issues Map
5
TDV Goals - Statewide

• Bldg population with lower peak demands
• Lower peak costs for electricity system
• Insurance against future blackouts
• Long-term demand reduction
• Cheapest to do with new construction (rather than
  retrofit)

6
TDV Goals - Compliance

• Replace flat rate energy basis
• Transparent to compliance end-user
• Credit for measures that perform on-peak, less
  for off-peak measures
• Better signals to designers
• Method tied to CEC weather tapes and ACM
  performance calcs

7
TDV Policy Choices

• Change savings valuation in Title 24
• Abandon source energy flat valuation
• Replace with time dependent valuation
• Change source energy
• Abandon electricity source energy (mult 3)
• Replace with TDV energy (hourly factors) based on
  CEC forecasts of costs
• Distinguish between natural gas propane

8
TDV Policy Choices (continued)

• Adopt economic valuation methodology
• Publicly available (mostly CEC) data sources
• Repeatable over time
• Easily adjusted as forecasts changebut not
  expected to update frequently
• Adopt engineering analysis upgrades
• Hourly HVAC equipment models
• Hourly analysis of measures
• Others...

9
TDV Policy Choices (continued)

• Uses of TDV
• For optional performance trade-offs
• For new compliance options
• For demonstrating cost-effectiveness of new
  standards requirements

10
TDV Policy Choices (continued)

• Methodology Choices (our recommendations)
• Use 1992 Standards valuations? (no)
• Use current CEC forecast? (yes)
• Use temp-dependent allocation of TD? (yes)
• True up to overall revenue requirements? (yes)
• Use environmental externalities? (yes)

11
Why Not Use Rates?

• There are many different rates (which?)
• Rates average the high cost periods and dilute
  the price signal
• Rates change with policy/political choices

• TDV reflects long-term system costs
• CEC 30 year generation forecast
• Utility TD cost experience
• Overall revenues to run utility system

12
How TDV Works (electricity)
Energy value
Monday
Friday
13
Building up the Electric TDVs
1. Start with the CEC Forecast Commodity Costs
2. Add the marginal TD delivery costs as f(temp)
3. Adjust to bring to revenue requirement (rate
levels)
4. Add environmental externality of reduced
pollution (optional)
5. Convert to equivalent energy units (TDV energy
units)
Forecast Costs
TDV Energy Value
Revenue Neutrality Adjustment
Monday Tuesday Wednesday Thursday
Friday
14
Building up Gas and Propane TDVs
1. Start with the CEC Forecast Gas Commodity Costs
2. Adjust to bring to revenue requirements (rate
levels)
3. Add environmental externality of reduced
pollution (optional)
4. Convert to equivalent energy units (TDV energy
units)
Forecast Costs
Energy Value
Revenue Neutrality Adjustment
December
January
15
Components of TDV for CTZ 13
16
Sources of TDV Economics Data
17
How Does TDV Compliance Work?

• Used for performance trade-offs(instead of old
  source energy trade-offs)
• Compliance runs done per usual
• Compliance software enhanced to do hourly
  base/proposed calculations
• TDV value for each hour multiplied by hourly
  energy, totaled for annual savings
• Same compliance report printed out

18
Changes to Title 24 for TDV

• Delete definition of SOURCE ENERGY
• Add definition of TDV ENERGY
• Adjust ACM rules for engineering enhancements
• Adjust rules for propane natural gas
• Adjust ACM output reports

19
Questions and Commentson TDV Economics
20
TDV Engineering Enhancements

• Goal Credit air conditioning systems that
  perform better on-peak
• Hourly equipment model for residential
• Improved performance curves for nonres
• Goal Improved treatment of water heating
• Hourly hot water usage profiles
• More complete distribution options
• Goal Credit other measures that perform better
  on-peak (e.g. cool roofs, daylighting)

21
Residential TDV Modeling

• Air Conditioners
• Heat Pumps
• Duct Systems in Attics

Engineering ACM Enhancement to better implement
TDV
22
Residential Air Conditioners

• Historical perspective
• Sensible loads
• SEER as Seasonal Efficiency
• 2001 Standards changed
• Conservative EER/SEER assumption
• Temperature and installation adjusted SEER
• as seasonal efficiency

23
2001 EER/SEER assumption
24
2001 Temperature adjusted SEER
25
TDV Air Conditioner Model

• NAECA SEER primary input
• 2001 EER/SEER assumed at 95 degF
•  Efficiency above 95F based on PGE tests
• Optional EER input
• Constant 62 WB indoors

26
TDV AC Efficiency vs. Outdoor Temp
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TDV Indoor Air Handler Fan

• Adjust SEER and EER to remove fan
• Fan is defaulted not tested
• 365 w/1000 CFM assumed
• 510 W/1000 CFM actual (Proctor)
• Model fan power separately
• Assume 300 CFM/ton, 510 W/1000 CFM
• Allow inputs for field verified CFM and W

28
TDV Heat Pump Model

• HSPF is primary input
• Default COP at 47F 0.4 x HSPF
• Capacity at 47F
• Default to Rated Cooling Capacity
• DOE2 hourly model

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TDV Default Heat Pump COP47

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TDV Hourly Duct Efficiency

• For ducts in attics
• Adjusts ACM Seasonal Efficiency on an hourly
  basis for heating and cooling
• Roof Sol Air Temperature driven
• Includes effects of all current options
• Invisible to ACM user

31
Residential Water Heating

• Engineering ACM Enhancement
• to better implement TDV

32
Load Dependent Energy Factor (LDEF) Annual
Method
33
Load Dependent Energy Factor (LDEF) Hourly
Method
34
Load Dependent Energy Factor (LDEF) Coefficients
35
Distribution System Multipliers(Being Revised)
36
Hourly Loads

• Make consistent with current method

37
Loads from Multifamily Study
38
Example Loads from EPRI/LBNL Study
39
Redefining Nonresidential Equipment Performance
Curves
Engineering ACM Enhancement to better implement
TDV
40
Nonres Performance Background

• Use ACM software for whole-building trade-offs
• Requires two energy simulations
• proposed design
• budget building.
• The rules tightly defined by the ACM manual.
• The default curves were developed in the 1970s
  some were updated with the 1993 supplement.
• Propose changes to the ACM manual
• allow users to input data for particular HVAC
  equipment
• update of the default curves to reflect
  performance of modern equipment.

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The Five DOE-2 Curves
wet, dry bulb temperature
COOL-CAP-FT
cooling capacity
wet, dry bulb temperature
cooling energy input ratio
COOL-EIR-FT
COOL-EIR-PLR
part load ratio
energy input ratio
dry bulb temperature
HEAT-CAP-FT
heating capacity
dry bulb temperature
HEAT-EIR-FT
heating EIR
42
Our Initial Approach

• Investigated the technologies for 150 different
  rooftop package units from several manufacturers
• Tried to draw conclusions between the
  technologies and performance.
• No statistically robust methods of predicting an
  actual performance curve based on the data
  available.

43
Current Approach Three Sets of Curves

• The current DOE default curve (from ACM)
• Best-fit curves
• The most accurate representation of the data set
  for each particular equation determined with
  least-squares regression
• Found divergences between the current defaults
  and actual performance
• P15 curves
• Lowest performing 15 of the data set..
• In general, equipment that performed poorly did
  so at all temperatures.
• Performed a least-squares regression on the worst
  performing subset to create the P15 curves.

44
Recommended Changes to ACM

• User Options
• 1) Input the performance data of their particular
  equipment directly into the compliance software.
  
• Best captures the details of the units
  performance
• 2) Do not input data - revert to the P15
  performance curves.
• Because these units represent the worst
  performers in the population, the user is
  motivated to use equipment with better
  performance and input it into the model.
• The reference building will use the best-fit
  performance curves for each piece of equipment.

45
COOL-CAP-FT - dependent on outside drybulb and
entering wetbulb temperatures
46
but to aid discussion, we reduce it to two
dimensions as shown below.
47
As expected, P15 Curves diverge from the current
defaults and best-fit at higher temperatures.
48
COOL-EIR-FT - normalized cooling efficiency as a
function of dry and wet bulb temperatures.
worse
better
49
Actual equipment performance is much worse than
the current DOE2 defaults at high temperatures.
P15
worse
best fit
current defaults
better
50
HEAT-CAP-FT - normalized heating capacity as a
function of outside dry bulb temperature
There is little divergence in the data for this
curve.
51
HEAT-EIR-FT - normalized heating efficiency as a
function of dry bulb temperatures.
worse
The worst performers significantly higher EIRs
below 37.
better
52
COOL-EIR-FPLR - normalized cooling efficiency as
a function of part load.

• Not recommending any changes to the current
  defaults
• Lack of scientific data
• Current manufacturer and scientific data was
  either non-existent or unavailable for study. We
  attempted a proxy based on Integrated Part Load
  Values (IPLV), but we did not have the defendable
  research to justify our modeling assumptions.
• DOE-2 modeling issues.
• Losses due to the cycling of compressors is a
  large factor in the overall part load performance
  of the equipment.
• Losses could not be quantified due to a lack of
  data
• Losses could not be modeled due to the non-linear
  discontinuities in the performance curve that are
  formed when a compressor cycles on or off.

53
Conclusions

• Changes to the ACM manual and default curves are
  needed to most accurately model present-day HVAC
  equipment
• Recommended approach is the best compromise
  between usability, accuracy, and consistency

54
Nonresidential Schedules
Engineering ACM Enhancement to better implement
TDV
55
Current Schedules

• Daytime Schedule
• 24-Hour Schedule

56
Recommended Schedules

• Continue to use the daytime and 24-hour schedules
  for LCC analysis and as a default
• Permit alternate schedules when the building use
  is known for offices, retail, schools and
  assembly
• Base the alternate schedules on the NRNC database

57
Lights
58
Equipment
59
Fans
60
Cooling Temperature
61
Heating Temperature
62
TDV Technical Analysis What happens to measures
and compliance trade-offs under TDV?
63
TDV Measures Analysis Method

• Perform annual energy simulation of building with
  existing compliance tools
• Residential - MicroPas
• Non-residential - EnergyPro
• Multiply hourly energy consumption for each fuel
  by its TDV value for that hour
• Sum hourly results over 8,760 hours
• Compare base case to proposed case

64
TDV Measures Analysis Graphs

• Comparison of source energy method and TDV energy
  method (two bars)
• Measures reported as savings (y-axis)
• Savings divided by total source energy or TDV
  energy of standard building
• Measures can be directly compared

65
Residential Analysis

• Four example houses provided by Consol
• Small house - 1290 sf, 1 story, 16.5 glazing
• Medium house - 2190 sf, 2 stories, 20.2 glazing
• Large house - 3278 sf, 2 stories, 25.8 glazing
• Townhouse - 1697 sf, 2 stories, 18.6 glazing
• 24 measures vs. to base configuration
• Climate zones 6, 12, 13, 14
• Compliance margin comparisons

66
Residential Measures

• 01 Windows U0.50, SHGF0.65
• 02 Windows U0.65, SHGF0.40
• 03 Windows U0.35, SHGF0.35
• 04 No radiant barrier
• 05 Radiant barrier
• 06 R38 ceiling
• 07 R30 ceiling
• 08 R19 ceiling
• 09 Wall R13
• 10 Wall R13 w/ foam R17.2
• 11 Wall R19
• 12 AC TXV (thermal expan valve)

• 13 AC SEER 12
• 14 AC SEER 14.4
• 15 Furnace AFUE 90
• 16 Duct R6
• 17 Duct R8
• 18 Tight ducts
• 19 ACCA standard ducts
• 20 DHW EF0.60 50 gal tank
• 21 DHW EF.62 40 gal tank
• 22 DHW pipe insulation
• 23 Glass area -10
• 24 Glass area 10

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Large Home - CZ 14 - Part 1
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Large Home - CZ 14 - Part 1
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Min/Max Comparisons
70
Nonresidential Analysis

• Two sample buildings
• Office - 117,000 sf, 6 stories, built-up VAV
• Retail - 50,000 sf, 1 story, packaged VAV
• Six measures
• Electric vs gas chillers
• Increase cooling efficiency
• Add economizer
• Add cool roof
• Lower SHGC on south and west
• Reduce lighting LPD by 20

71
Office - CTZ 14
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Retail - CTZ 14
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Externalities Analysis Results

• Consistency with CPUC measure valuation
• Adding externality costs have little effect on
  trade-offs between measures
• Slight effect on measures that reduce peak
  electricity demand
• Main effect is on evaluating the
  cost-effectiveness of measures that have a
  benefit/cost ratio close to 1.0

74
Externalities - CZ 14 Residential
75
Externalities - Retail CZ 14
76
Compliance Outcomes

• Any electricity saving measure is more valued by
  TDV than by source valuation
• Difference between flat and TDV indicates demand
  impact of measure
• Gas measures - minimal difference between flat
  and TDV gas
• Propane - TDV gives greater value to propane than
  to natural gas

77
Likely Winners/Losers

• Losers
• Propane (smaller advantage over elec)
• Economizers
• Other off-peak
• No Change
• Insulation
• Res. water heating

• Winners
• Peak air conditioning (SEER/EER issue)
• Fenestration (more directional)
• Gas cooling
• Cool roofs
• Other on-peak

78
Questions for a TDV Regime

• Does TDV appropriately increase valuation of peak
  measures? (yes)
• Does TDV maintain similar stringency as current
  standards basis? (depends)
• Does TDV create pathological cases? (none
  found yet)
• Possible to game TDV in ACM? (depends)
• Are engineering modeling changes ready? (mostly)

79
Why Change?

• Helps economy - least cost energy design
• Saves for everybody
• Right signals to designers(best way to do this)
• Right signals on costs(economists developed
  method)

80
Why Change?

• Flat, source energy is clearly incorrect
• Electricity demand crisis in CA
• Compliance process wont change
• Evolutionary change to standards
• Market-wide adjustments to building design and
  equipment selection
• Unique time in history to do this

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For More Information

• Project Web Site www.h-m-g.com
• PGE Gary Fernstrom
• 415-973-6054
• gbf1_at_pge.com
• HMG Douglas Mahone
• 916-962-7001
• dmahone_at_h-m-g.com