











3  EnvironmentalAnalysis






Steady State Surface Temperature
Component Index > Ladybug > 3  EnvironmentalAnalysis > Steady State Surface Temperature
Use this component to calculate a steady state interior/exterior surface temperature from given given indoor/outdoor air temperatures and surface UValues. Note that this component does not currently account for solar radiation, which can greatly alter surface temperatures in the real world.
The formulas used to account for air film resistance in this component come from ASHRAE Fundementals 2013, Chapter 26, Table 10 (26.20).
Inputs
Name  ID  Description  Type 
_outTemp  _outTemp  A number (or list of numbers) that represent the outdoor air temperature in degrees Celcius.  Goo 
_inTemp  _inTemp  A number (or list of numbers) that represent the indoor air temperature in degrees Celcius.  Goo 
_uValue  _uValue  A number that represents the UValue of the surface dividing the interior and exterior in SI (W/K·m2).  Goo 
intEmiss_  intEmiss_  A number between 0 and 1 that represents the interior emissivity of the surface dividing the interior and exterior. The default is set to 0.9 for a nonmetallic surface.  Goo 
srfOrient_  srfOrient_  A number between 180 (downwards) and 180 (upwards) that represents the angle in degrees of the direction of heat flow. This is related to the orientation of the surface dividing the interior and exterior. This input can also be the normal vector of a surface that is facing the correct direction of heat flow. The default is set to 0 degrees for a vericallyoriented surface (horizontal heat flow).  Goo 
outWindSpd_  outWindSpd_  A number (or list of numbers) that represents the outdoor wind speed in m/s. This is used to calculate the outdoor film coefficient. If no value is input here, a default of 6.7 m/s will be assumed (indicating a winter design day).  Goo 
Outputs
Name  ID  Description  Type 
inFilmCoeff  inFilmCoeff  The interior film coefficient as calculated by the interior emissivity, surface orientation and Chapter 26, Table 10 of AHSHRAE Fundemantals.  Goo 
extFilmCoeff  extFilmCoeff  Script variable ssSrfTemp  Goo 
inSrfTemp  inSrfTemp  The steady state interior surface temperature in degrees Celcius.  Goo 
extSrfTemp  extSrfTemp  The steady state exterior surface temperature in degrees Celcius.  Goo 