Location = Libraries/Location Specific/Locations
Each Type in the Type and Sub Type table contains a section that displays a screenshot of the Property Values Table showing the properties associated with the Type and Sub Type. In the case where the Sub Types have the same properties only one example of the Property Values table is shown. See Property Values Table to learn about how to interact with the table.
Note: Although not yet fully implemented the intent is that for each section there will be links directly to the EnergyPlus Input Output Reference. In addition the links will also be included in the Type and Sub Type Mapping Table.
The Type and Sub Type options that can be selected from the drop down lists in that area of the workspace, which filter the Source Library to display the variables the user can select to include, along with a value, in a Library Entry.
Note: The links within the table are to the EnergyPlus Input Output Reference and the explanations of the objects.
| Type Options | Sub Type Options | EnergyPlus Objects (IO Reference links) |
Location |
Default | Site:Location |
Ground |
Basement
Slab |
|
GroundTempUndist |
FiniteDiff
KasudaAchenbach |
|
Spectrum |
Data |
This field represents the latitude (in degrees) of the facility. By convention, North Latitude is represented as positive; South Latitude as negative. Minutes should be represented in decimal fractions of 60. (15’ is 15/60 or .25)
This field represents the longitude (in degrees) of the facility. By convention, East Longitude is represented as positive; West Longitude as negative. Minutes should be represented in decimal fractions of 60. (15’ is 15/60 or .25)
This field represents the time zone of the facility (relative to Greenwich Mean Time or the 0th meridian). Time zones west of GMT (e.g. North America) are represented as negative; east of GMT as positive. Non-whole hours can be represented in decimal (e.g. 6:30 is 6.5).
This field represents the elevation of the facility in meters (relative to sea level).
Used to specify the local variation in atmospheric properties at the site and should be used only if you require advanced control over the height-dependent variations for wind speed and temperature. The coefficients set by this object are used by EnergyPlus, in conjunction with the Site:WeatherStation object (see above), to calculate the local variation in atmospheric properties as a function of height above ground. Outdoor air temperature decreases with height, while wind speed increases with height. The local outdoor air temperature and wind speed are calculated separately for all zones and surfaces, and optionally for outdoor air nodes for which a height has been specified (see OutdoorAir:Node object). With the default inputs, wind speed falls significantly at heights lower than the weather station measurement height, and temperature increases slightly. The algorithms for this calculation are in the Engineering Reference. There are necessary correlations between the entries for this object and some entries in the Building object, specifically the Terrain field.
The wind speed profile exponent for the terrain surrounding the site. The exponent can be estimated from the table above (see Site:WeatherStation) or calculated beforehand using more sophisticated techniques, such as CFD modeling of the site terrain. Note that using this object overrides the wind speed profile coefficients implied by the Terrain field of the Building object even if this field is left blank.
The wind speed profile boundary layer thickness [m] for the terrain surrounding the site. The boundary layer can be estimated from the table above (see Site:WeatherStation) or calculated beforehand using more sophisticated techniques, such as CFD modeling of the site terrain. Note that using this object overrides the wind speed profile coefficients implied by the Terrain field of the Building object even if this field is left blank. This field can be set to zero to turn off all wind dependence on height.
The air temperature gradient coefficient [K/m] is a research option that allows the user to control the variation in outdoor air temperature as a function of height above ground. The real physical value is 0.0065 K/m. This field can be set to zero to turn off all temperature dependence on height. Note that the Air Temperature Sensor Height in the Site:WeatherStation object should also be set to zero in order to force the local outdoor air temperatures to match the weather file outdoor air temperature. This change is required because the Site:WeatherStation object assumes an air temperature gradient of 0.0065 K/m.
Ground temperatures are used for the ground heat transfer model. There can be only one ground temperature object included, and it is used as the outside surface temperature for all surfaces with Outside Boundary Condition=Ground. The object is options if you have no surfaces with ground contact. The outside surface temperature for individual surfaces can be specified using the OtherSideCoefficients (ref: SurfaceProperty:OtherSideCoefficients) object that allows Outside to be set with a schedule. This permits using any number of different outside face temperatures in addition to the ground temperature.
Each numeric field is the monthly ground temperature used for the indicated month (January=1st field, February=2nd field, etc.)
Site:GroundTemperature:FCfactorMethod is used only by the underground walls or slabs-on-grade or underground floors defined with C-factor (Construction:CfactorUndergroundWall) and F-factor (Construction:FfactorGroundFloor) method for code compliance calculations where detailed construction layers are unknown. Only one such ground temperature object can be included. The monthly ground temperatures for this object are close to the monthly outside air temperatures delayed by three months. If user does not input this object in the IDF file, it will be defaulted to the 0.5m set of monthly ground temperatures from the weather file if they are available. Entering these will also overwrite any ground temperatures from the weather file in the F and C factor usage. If neither is available, an error will result.
Each numeric field is the monthly ground temperature used for the indicated month (January=1st field, February=2nd field, etc.)
Site:GroundTemperature:Shallow are used by the Surface Ground Heat Exchanger (i.e. object: GroundHeatExchanger:Surface). Only one shallow ground temperature object can be included.
Each numeric field is the monthly surface ground temperature used for the indicated month (January=1st field, February=2nd field, etc.)
Site:GroundTemperature:Deep are used by the Pond Ground Heat Exchanger and Vertical Ground Heat Exchanger objects (i.e. objects: GroundHeatExchanger:Pond and GroundHeatExchanger:Vertical). Only one deep ground temperature object can be included.
Each numeric field is the monthly deep ground temperature used for the indicated month (January=1st field, February=2nd field, etc.)
Ground reflectance values are used to calculate the ground reflected solar amount. This fractional amount (entered monthly) is used in this equation:
Ground Reflected Solar = (Beam Solar X COS(Sun Zenith Angle) + Diffuse Solar) x Ground Reflectance
Of course, the Ground Reflected Solar is never allowed to be negative. The ground reflectance can be further modified when snow is on the ground by the Snow Ground Reflectance Modifier. To use no ground reflected solar in your simulation, enter 0.0 for each month.
Each numeric field is the monthly average reflectivity of the ground used for the indicated month (January=1st field, February=2nd field, etc.)
It is generally accepted that snow resident on the ground increases the basic ground reflectance. EnergyPlus allows the user control over the snow ground reflectance for both “normal ground reflected solar” calculations (see above) and snow ground reflected solar modified for daylighting. These are entered under this object and both default to 1 (same as normal ground reflectance – no special case for snow which is a conservative approach).
This field is a decimal number which is used to modified the basic monthly ground reflectance when snow is on the ground (from design day input or weather data values).
Ground Reflectance(used) = Ground Reflectance x Modifier(snow)
The actual Ground Reflectance is limited to [0.0,1.0].
This field is a decimal number which is used to modified the basic monthly ground reflectance when snow is on the ground (from design day input or weather data values).
Daylighting Ground Reflectance(used) = Ground Reflectance x Modifier(snow)
The actual Ground Reflectance is limited to [0.0,1.0].
The Site:WaterMainsTemperature object is used to calculate water temperatures delivered by underground water main pipes. The mains temperatures are used as default, make-up water temperature inputs for several plant objects, including: WaterUse:Equipment, WaterUse:Connections, WaterHeater:Mixed and WaterHeater:Stratified. The mains temperatures are also used in the water systems objects to model the temperature of cold water supplies.
Water mains temperatures are a function of outdoor climate conditions and vary with time of year. A correlation has been formulated to predict water mains temperatures based on two weather inputs:
· average annual outdoor air temperature (dry-bulb)
· maximum difference in monthly average outdoor air temperatures
These values can be easily calculated from annual weather data using a spreadsheet or from the ".stat" file available with the EnergyPlus weather files at www.energyplus.gov. Monthly statistics for dry-bulb temperatures are shown with daily averages. The daily averages are averaged to obtain the annual average. The maximum and minimum daily average are subtracted to obtain the maximum difference. For more information on the water mains temperatures correlation, see the EnergyPlus Engineering Document.
Alternatively, the Site:WaterMainsTemperature object can read values from a schedule. This is useful for measured data or when water comes from a source other than buried pipes, e.g., a river or lake.
If there is no Site:WaterMainsTemperature object in the input file, a default constant value of 10 C is assumed.
This field selects the calculation method and must have the keyword Schedule or Correlation.
If the calculation method is Schedule, the water mains temperatures are read from the schedule referenced by this field. If the calculation method is Correlation, this field is ignored.
If the calculation method is Correlation, this field is used in the calculation as the annual average outdoor air temperature (dry-bulb) [C]. If the calculation method is Schedule, this field is ignored.
If the calculation method is Correlation, this field is used in the calculation as the maximum difference in monthly average outdoor air temperatures [∆C]. If the calculation method is Schedule, this field is ignored.
The Site:Precipitation object is used to describe the amount of water precipitation at the building site over the course of the simulation run period. Precipitation includes both rain and the equivalent water content of snow. Precipitation is not yet described well enough in the usual building weather data file. So this object is used to provide the data using Schedule objects that define rates of precipitation in meters per hour.
A set of schedules for site precipitation have been developed for USA weather locations and are provided with EnergyPlus in the data set called PrecipitationSchedulesUSA.idf. The user can develop schedules however they want. The schedules in the data set were developed using EnergyPlus’ weather file (EPW) observations and the average monthly precipitation for the closest weather site provided by NOAA. EPW files for the USA that were based on TMY or TMY2 include weather observations for Light/Moderate/Heavy rainfall, however most international locations do not include these observations. The values were modeled by taking the middle of the ranges quoted in the EPW data dictionary. The assumed piecewise function is shown below.
Amounts (m/hr):
Light = 0.0125
Moderate = 0.052
Heavy = 0.1
The values were inserted on hour by hour basis for the month based on the observations. Then each month was rescaled to meet the average precipitation for the month based on the 30-year average (1971-2000) provided by the NOAA/NCDC. Therefore, the flags in the EPW file match the precipitation schedules for the USA. Note that summing the average monthly precipitation values will not give you the average yearly precipitation. The resulting value may be lower or higher than the average yearly value.
Once the typical rainfall pattern and rates are scheduled, the Site Precipitation object provides a method of shifting the total rainfall up or down for design purposes. Wetter or drier conditions can be modeled by changing the Design Annual Precipitation although the timing of precipitation throughout the year will not be changed.
Choose rainfall modeling options. Only available option is ScheduleAndDesignLevel.
Magnitude of total precipitation for an annual period to be used in the model. Value selected by the user to correspond with the amount of precipitation expected or being assumed for design purposes. The units are in meters. This field works with the following two fields to allow easily shifting the amounts without having to generate new schedules.
Name of a schedule defined elsewhere that describes the rate of precipitation. The precipitation rate schedule is analogous to weather file data. However, weather files for building simulation do not currently contain adequate data for such calculations. Therefore, EnergyPlus schedules are used to enter the pattern of precipitation events. The values in this schedule are the average rate of precipitation in meters per hour. The integration of these values over an annual schedule should equal the nominal annual precipitation.
Magnitude of annual precipitation associated with the rate schedule. This value is used to normalize the precipitation.
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