Transcript EnergyPlus Training Part 1

Lecture 4: Simulation Control,
Location, and Weather Input
Material prepared by GARD Analytics, Inc. and University of Illinois
at Urbana-Champaign under contract to the National Renewable Energy
Laboratory. All material Copyright 2002-2003 U.S.D.O.E. - All rights reserved
Importance of this Lecture to the
Simulation of Buildings
 Every building is different in many ways:
 Location and exterior thermal environment
 Construction
 HVAC system
 Exterior thermal environment is a driving force that
determines how a building will respond
 Energy efficient design requires an understanding of
and a response to the exterior thermal environment
 Thermal simulation requires information on the
exterior thermal environment to properly analyze the
building from an energy perspective
2
Purpose of this Lecture
Gain an understanding of how to control
the exterior environment of the
simulation

Building Location

Weather and Ground Temperature Data

Length of Simulation

Other General Features of the Input
3
Keywords Covered in this Lecture
 Version
 Run Control
 Location
 DesignDay
 SpecialDayPeriod
 RunPeriod
 DaylightSavingPeriod
 GroundTemperature
 GroundReflectance
 Snow Ground Reflectance Modifiers
4
Quick Review of Relationship
Between IDD and IDF Files
IDD: Input Data Dictionary
 File which defines what information should
be located in the user input file
 This file should NOT be modified
IDF: Input Data File
 User input file containing information about
the building and its primary and secondary
systems
 This file can be modified using a text editor
or using the IDF Editor
5
Keyword: Version
IDD Description
VERSION,
\unique-object
A1 ; \field Version Identifier
\required-field
Notes


\unique-object means only one of these
are allowed per IDF file
\required-field means this field must be
present in the description
6
Keyword Example: Version
 IDF Examples
Version, 1.1; ! Shortened input format
Version,
1.1; !- Version Identifier
 Notes:
 The Version identifier refers to a version of the
EnergyPlus program
 Updates in the EnergyPlus program may result in
changes to the IDD
 An error message will result if the IDF file version
does not correspond to the version of EnergyPlus
being run
 This course is based on EnergyPlus Version 1.1
7
Keyword: Location
IDD Description (shortened)
Location,
A1 , \field
N1 , \field
N2 , \field
N3 , \field
N4 ; \field
Location Name
Latitude
Longitude
TimeZone
Elevation
IDD Description (detailed)
Location,
Only one per IDF file
\unique-object
\min-fields 5
All five fields are required
A1 , \field Location Name
\required-field
Information expected: a name
\type alpha
Field is a character string
8
Keyword: Location
IDD Description (detailed, continued)
N1 , \field Latitude
Building site latitude (global position)
\units deg
\minimum -90.0
N1 in degrees
\maximum +90.0
Limits (-90≤N1≤+90) and Default Value
\default 0.0
\note + is North, - is South, degree minutes represented
\note in decimal (i.e. 30 minutes is .5)
Interpretation
\type real
Field is a decimal value
information
N2 , \field Longitude
\units deg
Building site longitude (global position)
\minimum -180.0
\maximum +180.0
\default 0.0
\note - is West, + is East, degree minutes represented
\note in decimal (i.e. 30 minutes is .5)
9
\type real
Keyword: Location
IDD Description (detailed, continued)
N3 , \field Time Zone
“Political” time zone
\units hr
N3 in hours
\minimum -12.0
\maximum +12.0
Note
\default 0.0
\note Time relative to GMT. Decimal hours.
\type real
N4 ; \field Elevation
Building site elevation
\units m
N4 in meters
\minimum -300.0
\maximum< 6096.0
\default 0.0
\type real
10
Keyword Example: Location
 IDF Example
Location, DENVER, 39.750, -104.870, -7.0, 1610.26;
or
Location,
DENVER COLORADO,
39.750,
-104.870,
-7.0,
1610.26;
 Notes:

!!!!!-
LocationName
Latitude {deg}
Longitude {deg}
TimeZone {hr (decimal)}
Elevation {m}
Location affects the sun angles, air properties, etc.
that the building experiences
11
Keyword: DesignDay
IDD Description (shortened)
DesignDay,
A1 , \field
N1 , \field
N2 , \field
N3 , \field
N4 , \field
N5 , \field
N6 , \field
N7 , \field
N8 , \field
N9 , \field
N10, \field
N11, \field
A2 , \field
N12; \field
DesignDayName
Maximum Dry-Bulb Temperature
Daily Temperature Range
Wet-Bulb Temperature At MaxTemp
Barometric Pressure
Wind Speed
Wind Direction
Sky Clearness
Rain Indicator
Snow Indicator
Day Of Month
Month
Day Type
Daylight Saving Time Indicator
12
Keyword: DesignDay
Purpose: the DesignDay input syntax
defines a single day of weather
information
Design day simulations are often used
for peak load or sizing calculations
Data required for this keyword can be
found in a variety of places (see next
slide)
13
DesignDay Sources
 MacroDataSets folder
 US, Canada, and International
 2001 ASHRAE data
 Datasets –
 US locations
 pre-1997 ASHRAE data, from BLAST library
 *.ddy files
 Included in weather data zip files on web site
 2001 ASHRAE data
14
Keyword: DesignDay
IDD Description (detailed)
Keyword—note all one word
DesignDay,
\min-fields 14
14 fields (all) required
A1 , \field DesignDayName
\type alpha
Unique character string
\required-field
name for design day
\reference DesignDays
N1 , \field Maximum Dry-Bulb Temperature Other
references to
\required-field
a design day
\units C
N1 is the maximum
in the IDF will
\minimum> -70
dry bulb temperature
expect an
\maximum< 70
experience for this
existing
\note
design day in degrees
design day
\type real
Celsius
name
15
Keyword: DesignDay
IDD Description (detailed)
N2 , \field Daily Temperature Range
\required-field
Range of temperatures expected
\units deltaC
\minimum 0
Units are D°C
Must
be
zero
or
greater
\type real
\note must still produce appropriate maximum dry bulb
N3 , \field Wet-Bulb Temperature At MaxTemp
\required-field
Mean coincident wet-bulb
\units C
temperature in °C
\minimum> -70
\maximum< 70
\type real
16
Keyword: DesignDay
IDD Description (detailed)
N4 , \field Barometric Pressure
\required-field
\units Pa
\minimum> 70000
\maximum< 120000
\type real
\ip-units inHg
N5 , \field Wind Speed
\required-field
\units m/s
\minimum 0
\maximum 40
\ip-units miles/hr
\type real
Outdoor barometric
pressure (assumed
constant for entire
day) in Pascals
IP Units if interface
accepts these units
Wind speed
(assumed constant
for entire day) in
meters per second
17
Keyword: DesignDay
IDD Description (detailed)
N6 , \field Wind Direction
Wind direction
\required-field
(assumed constant
\units deg
for entire day) in
\minimum 0
degrees (assumes
\maximum 359.9
North is 0, East is
\note North=0.0 East=90.0
90, South is 180,
\type real
etc.)
N7 , \field Sky Clearness
\required-field
Sky clearness
\minimum 0.0
(assumed constant
Maximum allows for
\maximum 1.2
for entire day)
altitude adjustment
\default 0.0
\note 0.0 is totally unclear, 1.0 is totally clear
\type real
18
Keyword: DesignDay
IDD Description (detailed)
N8 , \field Rain Indicator
Rain flag (assumed
\minimum 0
constant for entire
\maximum 1
day) affects
\default 0
exterior convection
\note 1 is raining, 0 is not
coefficients
\type integer
Rain flag (assumed
N9 , \field Snow Indicator
constant for entire
\minimum 0
day) affects ground
\maximum 1
reflectance
\default 0
\note 1 is Snow on Ground, 0 is no Snow on Ground
\type integer
Should be an
integer value not a
decimal number
19
Keyword: DesignDay
IDD Description (detailed)
Numerical day of
N10, \field Day Of Month
month (must be
\required-field
valid for month
\minimum 1
chosen)
\maximum 31
\type integer
\note must be valid for Month field
N11, \field Month
\required-field
Numerical month of
\minimum 1
the year
\maximum 12
\type integer
20
Keyword: DesignDay
Type of day/day of
the week for design

day (may affect
A2 , \field Day Type
schedule values)
\required-field
\note Day Type selects the schedules appropriate
\note for this design day
This field is a choice
\type choice
of one of the
\key Sunday
options listed as
\key Monday
\key
\key Tuesday
IDD Description (detailed)
\key
\key
\key
\key
\key
\key
\key
\key
\key
Wednesday
Thursday
Friday
Saturday
Holiday
SummerDesignDay
WinterDesignDay
CustomDay1
CustomDay2
This field must
equal one of these
choices of keywords
(note that none of
these keywords has
spaces)
21
Keyword: DesignDay
IDD Description (detailed)
N12; \field Daylight Saving Time Indicator
\minimum 0
Whether daylight
\maximum 1
savings time should be
\default 0
in effect for this design
\note 1=Yes, 0=No
day
\type integer
22
Keyword Example: DesignDay
IDF Example
DesignDay,
DENVER COLORADO SUMMER, !- DesignDayName
32.8,
!- Maximum Dry-Bulb Temperature {C}
17.8,
!- Daily Temperature Range {C}
15.0,
!- Wet-Bulb Temperature At MaxTemp {C}
84060.0, !- Barometric Pressure {Pa}
3.97,
!- Wind Speed {m/s}
146.0,
!- Wind Direction {deg}
1.10,
!- Sky Clearness
0,
!- Rain Indicator
0,
!- Snow Indicator
21,
!- Day Of Month
7,
!- Month
Monday, !- Day Type
0;
!- Daylight Saving Time Indicator
23
Keyword: DaylightSavingPeriod
 IDD Description (shortened)
DaylightSavingPeriod,
A1, \field StartDate
A2; \field EndDate
 Purpose: define the time frame during which
daylight savings rules should apply
 Note that this can be specific to location (not
all sites use daylight savings time in the
summer)
24
Keyword:
DaylightSavingPeriod
IDD Description (detailed)
Keyword—note all one word
DaylightSavingPeriod,
\unique-object
\min-fields 2
\memo This object sets up the daylight saving period
\memo for any RunPeriod.
\memo Ignores any daylightsavingperiod values on the
\memo weather file and uses this definition.
\memo (These are not used with DesignDay objects.)
A1, \field StartDate
Note: not used for design
\required-field
days and will override any
information found on the
Date when daylight
weather file
savings goes into effect
(details on format on next
slide)
25
Keyword:
DaylightSavingPeriod
IDD Description (detailed)
Date when daylight
A2; \field EndDate
savings period ends
\required-field
\memo Dates can be several formats:
\memo <number>/<number> (month/day) Format information
\memo <number> <Month>
for start and end date
\memo <Month> <number>
of daylight savings
\memo <Nth> <Weekday> in <Month)
time (see examples
\memo Last <WeekDay> in <Month>
below)
\memo <Month> can be January, February, March, etc.
\memo Months can be the first 3 letters of the month
\memo <Weekday> can be Sunday, Monday, Tuesday, etc.
\memo <Nth> can be 1 or 1st, 2 or 2nd, etc. up to 5(?)
Date examples:4/11 OR 11 April OR April 11
1st Sunday in April OR 1 Sunday in Apr
Last Sunday in October
26
Keyword Example:
DaylightSavingPeriod
IDF Examples
DaylightSavingPeriod,
1st Sunday in April,
!- Start Date
Last Sunday in October; !- End Date
or
DaylightSavingPeriod,
4/1,
!- Start Date
31 October; !- End Date
27
Keyword: SpecialDayPeriod
 IDD Description (shortened)
SpecialDayPeriod,
A1, \field Holiday Name
A2, \field StartDate
N1, \field duration (number of days)
A3; \field SpecialDayType
 Purpose: to set up the occurrence of special
days throughout the year or to override the
values set in a weather file
 Note: this information does not apply to
design days
28
Keyword: SpecialDayPeriod
IDD Description (detailed)
SpecialDayPeriod,
Keyword—note all one word
\min-fields 4
\memo This object sets up holidays/special days to be
\memo used during weather file run periods.
\memo (These are not used with DesignDay objects.)
\memo Depending on the value in the run period, days
\memo on the weather file may also be used. However,
\memo the weather file specification will take
\memo precedence over any specification shown here.
\memo (No error message on duplicate days or
\memo overlapping days).
Unique identifying name
A1, \field Holiday Name
\required-field
29
Keyword: SpecialDayPeriod
IDD Description (detailed)
A2, \field StartDate
Date when period
\required-field
starts; format
\memo Dates can be several formats: similar to dates for
\memo <number>/<number> (month/day) daylight savings
\memo <number> <Month>
time
\memo <Month> <number>
\memo <Nth> <Weekday> in <Month)
\memo Last <WeekDay> in <Month>
\memo <Month> can be January, February, March, etc.
\memo Months can be the first 3 letters of the month
\memo <Weekday> can be Sunday, Monday, Tuesday, etc.
\memo <Nth> can be 1 or 1st, 2 or 2nd, etc. up to 5(?)
N1, \field duration (number of days)
\minimum 1
Length of special
\maximum 366
30
period in days
\default 1
Keyword: SpecialDayPeriod
IDD Description (detailed)
A3; \field SpecialDayType
\required-field
\note SpecialDayType selects the schedules
\note appropriate for each day so labeled
\type choice
\key Holiday
Note the
\key SummerDesignDay
impact on
\key WinterDesignDay
schedules
\key CustomDay1
\key CustomDay2
\default Holiday
Type of day
(see
choices
given in
the \key
list) this
should be
considered
31
Keyword Example:
SpecialDayPeriod
IDF Example
SpecialDayPeriod,
Memorial Day,
Last Monday in May,
1,
Holiday;
!!!!-
Holiday Name
Start Date
duration (number of days)
SpecialDayType
32
Keyword: RunPeriod
 IDD Description (shortened)
RunPeriod,
N1 , \field
N2 , \field
N3 , \field
N4 , \field
A1 , \field
A2, \field
A3, \field
A4, \field
A5, \field
A6; \field
Begin Month
Begin Day Of Month
End Month
End Day Of Month
Day Of Week For Start Day
Use WeatherFile Holidays/Special Days
Use WeatherFile DaylightSavingPeriod
Apply Weekend Holiday Rule
Use WeatherFile Rain Indicators
Use WeatherFile Snow Indicators
 Purpose: to define the simulation period for
EnergyPlus (program does not assume entire year
simulation)
33
Keyword: RunPeriod
IDD Description (detailed)
Keyword—note all one word
RunPeriod,
\min-fields 10
N1 , \field Begin Month
\required-field
\minimum 1
Starting date for period
\maximum 12
to be simulated;
\type integer
entered as two separate
N2 , \field Begin Day Of Month
fields, both integer
\required-field
values
\minimum 1
\maximum 31
\type integer
34
Keyword: RunPeriod
IDD Description (detailed, continued)
N3 , \field End Month
\required-field
\minimum 1
\maximum 12
\type integer
N4 , \field End Day Of Month
\required-field
\minimum 1
\maximum 31
\type integer
Ending date for period
to be simulated;
entered as two separate
fields, both integer
values
35
Keyword: RunPeriod
IDD Description (detailed, continued)
A1 , \field Day Of Week For Start Day
\note =<blank - use WeatherFile>
\default UseWeatherFile
Day of week for starting
Note that
\type choice
date; can be used to
this is not a
\key Sunday
override day of week
“required”
\key Monday
specified on the weather file
field due to
\key Tuesday
the lack of
\key Wednesday
the line that
\key Thursday
Options for day of week
says
\key Friday
for starting date
“\required\key Saturday
field”; all
\key UseWeatherFile
fields after
this point are
also optional
36
Keyword: RunPeriod
IDD Description (detailed, continued)
A2,
A3,
\field Use WeatherFile Holidays/Special Days
\note If yes or blank, use holidays on Weatherfile.
\note If no, do not use the holidays on Weatherfile.
\note Note: You can still specify holidays/special days
\note using the SpecialDayPeriod object(s).
\type choice
These two input fields are used to override the
\default Yes
definition of holidays and daylight savings time
\key Yes
period from the weather file.
\key No
\field Use WeatherFile DaylightSavingPeriod
\note If yes or blank, use period specified on Weatherfile.
\note If no, do not use period as specified on Weatherfile.
\type choice
\default Yes
The choices for these fields are
\key Yes
simply a “yes” or a “no”.
37
\key No
Keyword: RunPeriod
IDD Description (detailed, continued)
A4,
A5,
A6;
\field Apply Weekend Holiday Rule
\note if yes and single day holiday falls on weekend,
\note "holiday" occurs on following Monday
\type choice
These three input
\key Yes
fields are used to
\key No
override the
\default No
\field Use WeatherFile Rain Indicators
definition of holiday
\type choice
weekend rules,
\key Yes
presence of rain
\key No
indicators, and
\default Yes
presence of snow
\field Use WeatherFile Snow Indicators
indicators from the
\type choice
weather file.
\key Yes
\key No
\default Yes The choices for these fields are
simply a “yes” or a “no”.
38
Keyword Example: RunPeriod
IDF Example
RunPeriod,
1,
1,
3,
31;
!!!!-
Begin Month
Begin Day Of Month
End Month
End Day Of Month
or
RunPeriod,
1,
1,
3,
31,
Tuesday,
Yes, Yes,
!- Begin Month
!- Begin Day Of Month
!- End Month
!- End Day Of Month
!- Day of Week for Start Day
Yes, Yes, Yes; !- Special Weather File Flags
39
Keyword: Run Control
IDD Description (shortened)
RUN CONTROL,
A1, \field
A2, \field
A3, \field
A4, \field
A5; \field
Do
Do
Do
Do
Do
the
the
the
the
the
zone sizing calculation
system sizing calculation
plant sizing calculation
design day simulations
weather file simulation
Purpose: overall control of what the
user wants EnergyPlus to simulate
(design days and/or weather file runs,
perform auto-sizing)
40
Keyword: Run Control
IDD Description (detailed)
RUN CONTROL,
\unique-object
A1, \field Do the zone sizing calculation
\type choice
\key Yes
\key No
\default No
A2, \field Do the system sizing calculation
\type choice
\key Yes
\key No
\default No
A3, \field Do the plant sizing calculation
\type choice
\key Yes
\key No
\default No
Keyword—
note that
there IS a
space
between the
two words
These
will be
discussed
later in
the
semester
41
Keyword: Run Control
IDD Description (detailed, continued)
A4, \field Do the design day simulations
\type choice
Choices for both fields are
\key Yes
simply “yes” or “no”
\key No
\default Yes
A5; \field Do the weather file simulation
\type choice
Fields define whether or not to
\key Yes
simulate design days (defined by the
\key No
DesignDay input line) or an attached
\default Yes
weather file (see RunPeriod input
line)
42
Keyword Example: Run
Control
IDF Example
RUN CONTROL, No, No, No, No, Yes;
or
RUN CONTROL,
No,
!No,
!No,
!No,
!Yes; !-
Do
Do
Do
Do
Do
the
the
the
the
the
zone sizing calculation
system sizing calculation
plant sizing calculation
design day simulations
weather file simulation
43
Keyword: GroundTemperatures
 IDD Description (shortened)
GroundTemperatures,
N1 , \field January Ground Temperature
N2 , \field February Ground Temperature
N3 , \field March Ground Temperature
. . . etc . . .
N12; \field December Ground Temperature
 Purpose: to set the ground temperatures
experienced at the building location (impact
on places where the ground is in contact with
the building)
44
Keyword: GroundTemperatures
IDD Description (detailed)
GroundTemperatures,
Keyword—note all one word
\unique-object
12 values, one per month
\min-fields 12
N1 , \field January Ground Temperature
Repeated for
\required-field
each month of
\units C
the year
\type real
\default 13
Temperatures in Celsius; note
that these are temperatures at
the outside surface not “deep
ground” temperatures
45
Keyword Example:
GroundTemperatures
IDF Example
GroundTemperatures, 20.03, 20.03, 20.13, 20.30, 20.43, 20.52,
20.62, 20.77, 20.78, 20.55, 20.44, 20.20;
or
GroundTemperatures,
20.03, !- January Ground Temperature {C}
20.03, !- February Ground Temperature {C}
20.13, !- March Ground Temperature {C}
20.30, !- April Ground Temperature {C}
20.43, !- May Ground Temperature {C}
20.52, !- June Ground Temperature {C}
20.62, !- July Ground Temperature {C}
20.77, !- August Ground Temperature {C}
20.78, !- September Ground Temperature {C}
20.55, !- October Ground Temperature {C}
20.44, !- November Ground Temperature {C}
20.20; !- December Ground Temperature {C}
46
Keyword: GroundReflectances
IDD Description (shortened)
GroundReflectances,
N1 , \field January Ground Reflectance
N2 , \field February Ground Reflectance
N3 , \field March Ground Reflectance
. . . etc . . .
N12; \field December Ground Reflectance
Purpose: to set the reflectance of the
ground surrounding the building (affects
radiation incident on building surfaces)
47
Keyword: GroundReflectances
IDD Description (detailed)
GroundReflectances,
Keyword—note all one word
\unique-object
12 values, one per month
\min-fields 12
N1 , \field January Ground Reflectance
\default 0.2
Repeated for
\type real
each month of
\minimum 0.0
the year
\maximum 1.0
\units dimensionless
Note: values for reflectance are
highly dependent on the type of
ground cover around the
building—grass, dirt, concrete,
asphalt, etc.
48
Keyword Example:
GroundReflectances
IDF Example
GroundReflectances, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2,
0.2, 0.2, 0.2, 0.2, 0.2, 0.2;
or
GroundReflectances,
0.2, !- January Ground Reflectance
0.2, !- February Ground Reflectance
0.2, !- March Ground Reflectance
0.2, !- April Ground Reflectance
0.2, !- May Ground Reflectance
0.2, !- June Ground Reflectance
0.2, !- July Ground Reflectance
0.2, !- August Ground Reflectance
0.2, !- September Ground Reflectance
0.2, !- October Ground Reflectance
0.2, !- November Ground Reflectance
0.2; !- December Ground Reflectance
49
Keyword: Snow Ground
Reflectance Modifiers
 IDD Description (shortened)
Snow Ground Reflectance Modifiers,
N1, \field Ground Reflected Solar Modifier
\minimum 0.0
\default 1.0
N2; \field Daylighting Ground Reflected Solar Modifier
\minimum 0.0
\default 1.0
 Purpose: to account for the presence of snow
and how that impacts the ground reflectance
(weather files will indicate whether or not
there is snow on the ground)
50
Keyword: Snow Ground
Reflectance Modifiers
IDD Description (detailed)
Snow Ground Reflectance Modifiers,
N1, \field Ground Reflected Solar Modifier
\minimum 0.0
\default 1.0
\note Value for modifying the "normal" ground reflectance
\note when Snow is on ground when calculating the
\note "Ground Reflected Solar Radiation Value“ a value of
\note 1.0 here uses the "normal" ground reflectance
\note Ground Reflected Solar = (BeamSolar*CosSunZenith
\note
+ DiffuseSolar)*GroundReflectance
\note This would be further modified by the Snow Ground
\note Reflectance Modifier when Snow was on the ground
\note When Snow on ground, effective GroundReflectance is
\note GroundReflectance*"Ground Reflectance Snow Modifier"
\note Ground Reflectance achieved in this manner will be
51
\note restricted to [0.0,1.0]
Keyword: Snow Ground
Reflectance Modifiers
IDD Description (detailed)
N2; \field Daylighting Ground Reflected Solar Modifier
\minimum 0.0
\default 1.0
\note Value for modifying the "normal“ daylighting
\note ground reflectance when Snow is on ground
\note When calculating the "Ground Reflected Solar
\note Radiation Value“ a value of 1.0 here uses the
\note “normal” ground reflectance
\note Ground Reflected Solar = (BeamSolar*CosSunZenith
\note
+ DiffuseSolar)*GroundReflectance
\note This would be further modified by the Snow Ground
\note Reflectance Modifier when Snow was on the ground
\note When Snow on ground, effective GroundReflectance is
\note GroundReflectance*"Ground Reflectance Snow Modifier"
\note Ground Reflectance achieved in this manner will be
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\note restricted to [0.0,1.0]
Keyword Example: Snow Ground
Reflectance Modifiers
IDF Example
Snow Ground Reflectance Modifiers, 1.5, 2.0;
or
Snow Ground Reflectance Modifiers,
1.5, !- Ground Reflected Solar Modifier
2.0; !- Daylighting Ground Reflected Solar Modifier
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Summary
 Location and exterior thermal environment
play a critical role in determine the thermal
loads/energy consumption of a building
 Many input keywords in EnergyPlus control
what is being simulated

For example: Version, Run Control, Location,
DesignDay, SpecialDayPeriod, RunPeriod,
DaylightSavingPeriod, GroundTemperature,
GroundReflectance, Snow Ground Reflectance
Modifiers
 EnergyPlus flexibility also results in user
responsibility (having to define various
parameters in the input file)
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