For many years, the conventional method to account for these three energy interactions has been to incorporate an effective outdoor air temperature known as the sol-air temperature
(Kuehn et al.
The FCU model is also influenced directly or indirectly by both steady and time dependent factors that are included in the overall system simulation: device performance parameters, zone interior loads, outdoor air temperature and humidity, room and plenum sol-air temperature
, inlet cooling and heating water temperature.
The hourly data for three North American sites with very different climatic conditions (Edmonton, Houston, and Pittsburgh) provided by the US Department of Energy (DOE 2005) were used to calculate average daily profiles of sol-air temperatures
(ASHRAE 2005) for the roof and east and west walls for winter (December-February), spring (March-May), summer (June-August), and autumn (September-November).