The ambient data available within the Heat Transfer interfaces come from the processing of measured data from ASHRAE Weather Data Viewer 5.0 (©2013 ASHRAE, www.ashrae.org), given as frequencies of observations, monthly and hourly averaged for several past years of observation. They provide time-dependent weather conditions for more than 6000 stations worldwide in terms of the dry bulb temperature, the dew point temperature, the relative humidity, the wind speed, and the solar direct and diffuse irradiance.
See Ambient Settings for the settings related to the ambient variables in the Heat Transfer (
ht) and Heat Transfer in Thin Shells (
htsh) interfaces.