BO-2368 (RP 118) -- Effective Temperature (ET) as a Predictor of Thermal Comfort PDF

The concept of effective temperature stands as one of the major contfibutions to the body of research on thermal comfort. Introduced in 1923 by Houghten and Yaglou (1), effective temperature is a single index that combines the wet-bulb and dry-bulb temperatures with barometric pressure and air velocity for predicting thermal comfort. While still quite prominent in today's literature, the effective temperature index as originally proposed has long been recognized to overestimate the effects of humidity at cold temperatures and to underestimate its effects at high temperatures.

Partially to correct for this bias, but also to describe the relationship of man's beat exchange and his environment, a new effective temperature index was suggested by Gagge, Stolwijk, and Nishi (2) in 1971. This index, designated as ET , was defined as "the dry bulb temperature at the intersection of its loci with a SOP relative humidity curve found in an ASHRAE psychrometric chart rather than by the saturated temperature curve used earlier." These new ET 's were incorporated into the new ASHRAE Comfort Chart.