Sol-air temperature
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Sol-air temperature or Tsol-air is a variable used to calculate cooling load of a building and determine the total heat gain through exterior surfaces. It is an improvement over
q / A = ho * (To − Ts)
where
ho = heat transfer coefficient for radiation (long wave) and convection
To = outdoor surroundings' temperature
Ts = outside surface temperature
This equation only takes into account the temperature differences thus, ignoring solar radiative flux and infrared exchanges from the sky. The Tsol-air was then introduced to accommodate these two parameters.
Tsol − air = To + (aI − deltaqir) / ho
where
a = solar radiation absortivity of a surface
I = global solar irradiance
deltaqir = infrared radiation transfer of sky temperature to surface
and is to be used in
q / A = ho * (Tsol − air − Ts)
[edit] References
1. Fundamentals volume of the ASHRAE Handbook, ASHRAE, Inc., Atlanta, GA, USA, 2005
2. Heating and Cooling of Buildings, 2nd ed., Kreider, Curtiss, Rabl, McGraw-Hill, New York, USA, 2002
