SEEM Workshop
description
Transcript of SEEM Workshop
Ben Larson31 October 2011
[email protected] 9th Avenue NE, Seattle, WA 98105(206) 322-3753 Fax: (206) 325-7270
Simulation models and history in the PNW Why the RTF uses SEEM
SEEM capabilities overviewRunning SEEMOutputs Inputs with examplesExample RTF measuresSEEM calibrationFuture plans for SEEM
2
Modeling Residential Building Performance
Models not predictive Mathematical tool to describe the
interaction components of the building Describe physical relationship between the
determinants of consumption Space conditioning especially heating Building heat loss and heat gain Impact of occupant behavior Thermostat controlled loads Climate
Simulations not meant to describe or predict occupant behavior Appliances and plug loads notoriously
challenging4
PNW has used building energy simulation tools for energy planning since the first power plan
Larry Palmiter came to the region to develop a state of the art residential heating/cooling and solar model, SUNCODE
Early in this process a planning tool was needed to run fast and describe residential heating with a minimum number of inputs: SUNDAY
5
“Daily” simulation using the minimum information necessary
Allowed quick assessment of space heating measures and interactions that determine heating
Not designed to assess heating system delivery
Not able to correctly model coolingRequired side calculations to handle
these effects and other loads
6
An even faster correlation program: WATTSUN
Allowed very quick correlation look-up Added calculations not in simulation Heating equipment efficiency Duct efficiency Other loads
REMRATE uses a similar approach (although the look-up tables were developed from SUNCODE to be used in individual homes)
7
The region needed capabilities not in Sunday/Wattsun Cooling load estimates Simulation of heat pump and AC equipment Duct sealing and duct efficiency impacts Ventilation interactions
SEEM developed around a similar concept to SUNDAY Minimum inputs to get an accurate answer Simplified inputs that allow parameter studies Direct platform to integrate findings from field
work, lab testing, and calibration exercises No direct simulation of occupancy based loads
8
Developed beginning in 2003 by Larry Palmiter Passed to Ben Larson in 2008. Updates in 2011 carried out by Michael Logsdon. Funded initially by NEEA and the NPCC Enhanced with a consortium of regional energy
offices led by Idaho (funded by USDOE) Enhanced with funding from BPA, NEEA and RTF Current version SEEM92 (.92) reflects all these
upgrades. Ongoing efforts to add capabilities:
Ventilation systems Scheduling of internal gains Better user template
9
Allows direct simulation of heating and cooling measures Insulation and heat loss rate Building HVAC equipment
▪ Heat pump▪ A/C▪ Ducting sealing▪ Delivery efficiency
Parameterize measures for comparison in conservation supply curves
Direct calibration to empirical field data and lab testing
10
Calculates annual building heating and cooling energy use Developed specifically for single family residential
buildings Single zone model (treats the conditioned space as one big
room) Also appropriate for small-scale multi-family construction
including townhouses and 3-5 story flats
Differentiating features: Empirically derived heat pump performance maps
▪ Multiple control strategy possibilities Full duct model include losses to and regain from buffer spaces Ground contact heat transfer based on ISO standard handles many
types of construction and insulation Input and output via CSV file allows for large parametric studies and
flexible analysis11
Simple Energy Enthalpy Model
Pairwise Comparisons Compare proposed building against a base case for
compliance purposes Single Building Studies (1 to 50 runs)
Examine multiple measures for best energy savings opportunities and cost effectiveness
Medium Scale Studies (50 to 1,000 runs) Writing TCOs for NW Energy Star program Regional window retrofit measure
Large Scale Studies (5,000 to 500,000 to 1M+) Power Council 6th Power Plan Residential Sector Generate and analyze runs with scripts
12
Provide enough information to start modeling a generalized building population Suitable for comparing codes and
standards or determining savings values for a conservation program
Interpret SEEM output In-depth explanation of developing
simulation inputs
13
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 (Coefficient of Performance)
14
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
included 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
15
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
16
Currently does not directly model ventilation interactions
Currently does not model occupancy schedule except Tstat setback
Interface does not have a menu of pre-determined, selectable inputs
Single zone model coupled w/ buffer spaces House energy uses such as lighting, DHW,
etc. require add’l engineering calculations Certain inputs, ex: Qgains, require add’l
engineering calculations
17
SEEM is a calculation engineYou are the model(er)Output is only as good as the inputYou are responsible for setting the
proper baseline, assigning the correct inputs, and doing any simulation post-processing
18
Under the hood - Uses input.csv file & output.csv text files
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▪ Excel workbook needs to know where SEEM is on your
computer▪ “Locate SEEM” button
Example: ex1-nwcities.xls 19
UATotal (Btu/hr F) calculated UA Total UA from house to outside and ground including air infiltration.
HDD65 (°D)° Heating Degree Days Base 65 Heating degree days base 65 for input climate
CDD65 (°D) Cooling Degree Days Base 65 Cooling degree days base 65 for input climate
Pressure (atm) Site pressure in std atmospheres Can be used to correct for altitude effects on mass flow
RoomHeatkWh (kWh) Annual house heating load Heat which must be delivered to house (conditioned zone)
EquipHeatkWh (kWh) Annual heating equipment output Heat 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 input Site energy required to produce equipheat. Includes the effects of equip. eff., duct losses, and fan energy. Includes all auxheat.
AuxHeatkWh (kWh) Annual electric strip heat Used for heat pumps when compressor not meeting load
FanHeatkWh (kWh) amount of energy used by the fan This heat is included in equipheat. The fanheat is equal to the fan input power.
FanHeathrs (hr) total fan run time in heating mode Equals the equipment runtime in heating mode.
RoomCoolkWh (kWh) annual house cooling load Cool which must be delivered to house (conditioned zone)
EquipCoolkWh (kWh) annual cooling equipment output Cool supplied by equipment into duct system. Includes the effects of duct losses and fan heat.
InCoolkWh (kWh) annual cooling equipment input Site energy required to produce equipcool. Includes effects of equip. eff., duct losses, and fan energy.
QLatentkWh (kWh) annual latent load in cooling mode Amount 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 met20
Determine energy differences between buildings Need a base case Need one (or multiple) proposed case
Prototype building Building dimensions generally stay the same –
measures such as insulation, duct leakage, equipment change between runs
Example: ex2-windows.xls 2200ft2 Prototype - current average U.S. house size Split level house w/ some second floor space above
garage Double Triple pane window comparison
21
Run: label, weather, hourly output Occupancy: thermostat (temperature, time, &
setback), internal heat and moisture gains Equipment: type, size, control strategy Duct: location, leakage, insulation Envelope: areas, volumes, insulation, windows
(including orientation, shading, SHGC) Foundation: type, area, perimeter, insulation Infiltration: ACH for house, attic, and crawl
Definitions in seem92_csv_inout.xls
22
Run Label – Descriptive name of particular simulation. Can be used to identify which measures are used in that run.
Weather Name – name of weather file. Ex: IDBoise3 or WASpokane3 uses the TMY3 weather data for those cities.
Hourly Out – flag to produce hourly output for hottest and coldest day in a “.SEEM” file for each run (useful for testing and verification)
OutputMonth and Output Day – user settable output day to be included in .SEEM file
23
24
Entered as State-City-tmytype: ORPortland3 Linked to Weather data files
The NW regional weather zones used in many analyses are compiled from a percentage of PNW typical climates:
Location Climate DataHeating Zone Weight Data
Heating Zone 1 20% 50% 15% 15% 0% 100%Heating Zone 2 0% 0% 85% 10% 5% 100%Heating Zone 3 0% 0% 0% 0% 100% 100%
PNW Region 20% 40% 15% 20% 5% 100%Heating Degree Days Base 65 4187 4641 6716 5396 7828
Location Climate DataCooling Zone Weights
Cooling Zone 1 5% 80% 0% 0% 15% 100%Cooling Zone 2 35% 0% 55% 10% 0% 100%Cooling Zone 3 0% 0% 0% 100% 0% 100%
PNW Region 35% 25% 20% 15% 5% 100%Cooling Degree Days Base 65 367 128 341 756 127
Region
Portland Seattle Spokane Boise Kalispell Region
Portland Seattle Spokane Boise Kalispell
Theathi – occupied T set point Theatlo – unoccupied/setback set point Hrheathi – hour to start occ. mode Hrheatlo – hour to start unocc. mode Tcoollo, Tcoolhi, hrcoolhi, hrcoollo – similar to above but
for cooling Setback – 1 or 0 to use setback or not
▪ For electric forced air furnace and electric zonal resistance use 66F heating set point w/ no setback (RTF decision, November 2009)http://www.nwcouncil.org/energy/rtf/meetings/2009/11/Default.htm
Typical Thermostat Setup ValuesTheathi Theatlo hrheathi hrheatlo Setback
(F) (F) (hr) (hr) (1 or 0)70 64 6 22 1
Tcoollo Tcoolhi hrcoolhi hrcoollo (F) (F) (hr) (hr) 74 78 9 17
25
#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 ~1.5 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 26
Example: ex3-gains.xlsPrototype: 2200 ft2
Envelope: NWBOP1Equipment: Gas Furnace AFUE 90Explore impact of lighting levels on
gains and energy use in Spokane Lighting levels: All incandescent, 50%
CFLs, 75% CFLs, 90% CFLs
27
Equiptype – furnace, heat pump, or furnace and A/C combination Internally, SEEM assumes an electric furnace
with COP of 1. To model a gas furnace with AFUE 80, divide inheatkwh output by 0.8.
Common values:▪ Current Codes: 7.7/13▪ EnergyStar: 8.5/13
To get a value not listed in the table, interpolated between independent runs
Furnace A/C Combinations:▪ FYKC, FHPA, FHCA, FYSA
Example: ex4-equip.xls
Heat Pump OptionsLabel HSPF SEERYKC 7.2 10
HPA3 8 13HCA3 7.9 13YSA 9 14.5
28
Tons – size of heat pump or air conditioner Typical range: 2-4 tons
▪ If sized too small, more electric resistance auxiliary heat is used and cooling load may not be met.▪ hrsetptmissed output
▪ If sized too large, a part load cycling penalty is incurred Furnsize – elec furnace size in kW.
Input not critical as SEEM will by default provide “missing” heat at COP of 1.
CFMmult – air handler flow multiplier Used to model low or high flow and to correct for
air mass flow at altitude (see documentation) Suggest leaving at 1.
29
HPcntrl – heat pump control strategy Tcntrl – temperature associated with strategy NW Regional Control Strategies:
Base Case and PTCSHeat Pump Baseline Control Strategy Matrix
Weight HPcntrl Tcntrl Description
0.4 0 30ARI standard control, if you aren't meeting setpoint within
3degF, turn on auxiliary electric
0.15 1 30Compressor lockout if outside temp is below temp (Tcntrl),
turn on electric only.
0.05 2 40Auxiliary heat lockout, compressor runs at reduced capacity
(Tout<Tcntrl)0.15 3 30 strip heat on with compressor if Tout<Tcntrl (30 deg)0.25 3 50 strip heat on with compressor if Tout<Tcntrl (50 deg)
Heat Pump PTCS Control Strategy MatrixWeight HPcntl Tcntrl Description
0.1 0 30ARI standard control, if you aren't meeting setpoint within
3degF, turn on auxiliary electric
0.9 2 40Auxiliary heat lockout, compressor runs at reduced capacity
(Tout<Tcntrl)30
Perfect – (1 or 0) no duct leakage or conduction losses
SDloc, RDloc – supply and return duct location: Attic, Crawl, In, Out
SDarea, RDarea – supply and return duct surface area in buffer spaces
SDRval, RDRval – true R-value of duct insulation. Round duct / flex duct nominal R-value is not true R-value:
Actual R-values of Round Duct R nominal 4.2 6 8 11
Nominal Duct Diameter (in)
Actual Duct Area (ft2 per
ft length)R actual
4 1.05 3.13 4.08 4.97 6.096 1.57 3.41 4.53 5.62 7.038 2.09 3.57 4.8 6.04 7.66
10 2.62 3.67 4.99 6.33 8.12 31
SDLF, RDLF – Supply and Return Duct Leakage Fraction (0-100%).
Typically model supplies in the crawl space and returns in the attic
Manufactured homes typically modeled with no return leaks
Houses with basements typically have reduced duct leakage
Example: ex5-ductlosses.xls
Typical Duct Leakage Values Supply ReturnNW Existing 15% 10%NW New Construction 12% 10%NW EnergyStar (sealed) 6% 3%
32
Units: Perimeter, Area, Volume in: ft, ft2, ft3
Insulation inputs – overall air-to-air R-value (inverse of the U-value). ▪ Values for walls can often be looked up in code or spec
tables.▪ Super Good Cents Heat Loss Reference Manual▪ ASHRAE Fundamentals Handbook▪ IECC Code Tables
▪ Values for ceilings and floors aren’t as straight forward because SEEM directly calculates buffer space effects
▪ Values can be found in the “docs\” folder of the distribution
SEEM_insulation_lookup_tables.xls33
Afloorcond – house conditioned floor area Volume – house volume Afloorext – floor area over
unconditioned space Rfloorext
Aextwall – gross exterior wall area Rextwall
Aceiling – ceiling area exposed to attic. Sum of Afootprint and Afloorext Rceiling
ABSroof – roof solar absorptivity. Depends on color and cleanness. Suggest 0.85.
34
AwinN, AwinE, AwinS, AwinW – window area for each cardinal direction
Uwindow – NFRC U-value for window Example: ex6-windows_5climate.xls
SHGC – NFRC solar heat gain coefficient value Shading – (o to 1) fractional value to account for
shading: External: trees, landscaping, adjacent buildings Internal: (delete)and curtains, blinds, furnishings 0.5 – 0.65 is reasonable. Suggest 0.54.
Adoor – total door area Rdoor
35
Foundtype – crawl space, slab, unheated basement, heated basement
Afootprint – area of house at grade
Pfloor – perimeter of house at grade
Rfloor – wood floor insulation value between house and crawl space
Rslabins – R-value of insulation underlying entire slab (if slab fully insulated)
Rcarpet – R-value of interior floor finishes
36
Edgetype – perimeter slab insulation Horizontal Vertical None
EdgeDepth – depth of edge insulation Typically: 2 ft, 4ft
Redgeins – R-value of edge insulation
SoilCond – site soil conductivity Typically 0.7-0.8 Btu / ftFhr but can
very greatly depending on site Suggest 0.75
Vertical Edge Insulation:
Horizontal Edge Insulation:
37
Crawl space or basement wall characteristics HeightAG RwallAG HeightBG RwallBG
38
ACHHouse – infiltration in natural air changes per hour Includes natural and fan forced ventilation ERVs can be modeled but adjustments need to be made to
infiltration rate based on equipment efficiency Approximate blower door test conversion:
▪ 7ACH@50Pa / 20 ~ 0.35 ACH natural
ACHAttic – 4.5, typical for vented attic ACHCrawl – 4.5, typical for vented crawl
House ACH ValuesTypical existing stock 0.45
Typical new construction 0.35Energy Star NWBOP1 0.35
WA Code 2010 Proposal 0.3Energy Star NWBOP2 0.2
39
(Adam’s Components)
May 31st , 2011
Example Runs of RTF Deemed Measures Duct Savings Heat Pump Savings Insulation Others
SEEM Calibration Calibration methodology
▪ Compare modeling output to metered data RTF-approved calibrations
▪ SF Weatherization (Adam demonstration) Future Needs
▪ Manufactured Homes
In general, for each measure Each prototype has its own set of pre-determined “fully weatherized” SEEM
inputs Very few (one or two) SEEM inputs are changed to create a pre- and post- run Savings are calculated for all iterations of prototypes, climate zones, and
sometimes heating system types, and weighted appropriately. Depending on the number of measures, the number of SEEM runs can get huge (especially with heat pumps)
Standard Prototypes Single Family
▪ 1344 ft2 on crawlspace▪ 2200 ft2 on crawlspace▪ 2688 ft2 on basement
Manufactured Homes… Multifamily… Note: For some measures, the standard prototypes are adjusted or new ones
are created▪ Examples: Large house for GSHP’s, slab foundation for slab insulation measures.
Climate Zones Portland Seattle Spokane Boise Kalispell
See this link for all the details of the single family SEEM runs (big file)
Primary SEEM Variables SDleak
▪ Pre: 15%▪ Post: 10%
RDleak▪ Pre: 5%▪ Post: 3%
Primary SEEM Variable Equiptype$
▪ Pre: HPA3▪ Post: YSA
Since YSA = HSPF 9.0 / SEER 14.5 and measure requires HSPF 9.0 / SEER 14.0, a simple ratio of SEER’s is applied to cooling energy use.
Heat pump measures involve the weighting of 5 control strategies (SEEM variables: HPcntrl and Tcntrl), so there are 5-times as many heat pump runs as other measures.
R19 to R-38 Attic Insulation Primary SEEM Variable
▪ Rceiling▪ Pre: 19.6▪ Post: 35.0
R-19 to R-30 Floor Insulation Primary SEEM Variable
▪ Rfloor▪ Pre: 22.0▪ Post: 30.6
Goal: Calibrate model using input assumptions that match real-world billing data.
Calibration: Where disagreement between SEEM and Real-World, turn ONLY the “knobs” that apply.
Example: Single Family Weatherization SEEM Runs Calibration Billing Data from 3 studies. Result: Adjusting SEEM inputs for the heating temperature setpoints to the following
resulted in a reasonable match:▪ Heat Pumps and Gas FAF:
▪ 70 degrees daytime▪ 64 degree night setback▪ Justification: Allows modeling of a night time setback for heat pumps (strip heaters), also takes into
account similar economics of running Gas FAF and heat pumps
▪ Electric FAF and Zonal Electric:▪ 66 degrees day and night▪ Justification:
Zonal electric: takes into account zoning (lower average house temperature) Electric FAF: factors in occupant’s ability to turn on/off heating system
Example: GSHP SEEM Runs Calibration Billing/metered data from 1 study (Missoula) Result: A reasonable match was achieved without making adjustments to the SEEM
model.
AverageHeat Pumps and Gas FAF 70/64 4% 0% 2% -7% -8% -2%Electric FAF and Zonal 66/66 -6% 1% 12% 8% 4%
Each StudyResults: SEEM Model kWh/sqft differs from Studies by x%
Heating System TypeHeating
Setpoints
Billing Study LocationHeating System
Sample SizeData Source
(goal)SEEM Model
ResultData
SourceSEEM Runs
Residential New Construction Bil l ing Analysis Market Research Report
(RLW for NEEA, 2007)WA Gas FAF 114 13,979 14,927 948 7%
Used WA gas heated homes due to large sample size and abil ity to disaggregate
space and water heating use.5.7 5.9
Zonal 305 4,728 4,468 -260 -6% 3.0 2.9
Heat Pump 36 7,835 7,876 40 1% 3.4 3.4
Zonal 346 4,907 4,954 47 1% 3.1 3.2
Heat Pump 53 8,055 8,114 60 1% 3.0 3.0
Electric FAF 212 11,539 12,896 1,357 12% 4.9 5.5
Heat Pump 212 7,383 6,888 -495 -7% 3.2 2.9
Electric FAF 169 9,631 10,375 744 8% 5.0 5.4
Heat Pump 169 6,168 5,680 -488 -8% 3.2 2.9
Data Source
Portland
Seattle
TriCities
RTF/NEEA Heat Pump StudyAssumed houses are weatherized.
Wood heat?HP controls estimated.
NW WA
Amount of wood heat unknown.Super Good Cents
Metered Data Report
Space Heat Use (kWh/year)
Difference(kWh/yr & %)
positive = SEEM overestimates
use
NotesHeating kWh/sqft
Internal Gains Scheduling Ventilation Model
Air balance within zones Stack driven infiltration Scheduled mechanical ventilation Combined natural and mechanical ventilation
Water Heater Model Driven by need to understand HPWHs Focus on HPWH interaction with condition (& buffer) space Water use schedule Equipment models
Ductless Heat Pumps Interface Enhancements
49
Screen output Scrolls by quickly and provides some error
feedback if problems encountered CSV file
Contains all of the runs Definitions in seem92_csv_inout.xls
“.SEEM” File Text file with hourly data for heating and cooling
design day and user selected day. One file per run. Definitions in seem92_hourly_file_description.doc
Hourly data dump Text file containing a years worth of hourly data
51
52