Flaws in the environmental temperature model

Abstract

The paper summarises the arguments which led to the establishment of 'environmental temperature' as a room index temperature and its attendant model for discussion of room internal heat exchange. The model leads to some logically absurd conclusions. The index proves to be flawed since it was defined in terms of air and mean surface temperature but interpreted as a mix of air and mean radiant temperature. The series of defects implicit in the setting up of the model are presented: the principle upon which environmental temperature was arrived at is invalid; the use of the global mean surface temperature is invalid; radiant exchange in a room was mishandled and the status of dry resultant temperature was misrepresented. Quite apart from errors of principle, the exposition of the model in the 1986 CIBSE Guide is unnecessarily complicated.