Location tab on model data at Site level
The Site height variation data is 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 here are used by EnergyPlus 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. 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 the Exposure to wind setting.
Note that using this object overrides the wind speed profile coefficients implied by the Terrain field of the Building object . The wind speed profile coefficients 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.
Check this checkbox to apply custom variation in atmospheric properties at the site.
The wind speed profile exponent for the terrain surrounding the site. The exponent can be estimated from the table above 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.
The wind speed profile boundary layer thickness (in m or ft) for the terrain surrounding the site. The boundary layer can be estimated from the table above 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 (in K/m or °F/ft) is a research option that allows the variation in outdoor air temperature to be defined 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.