Radiant heat from lights,and its effect on thermal comfort

Abstract

The radiation environment of a person can be described in terms analogous to those used in lighting: with mean radiant temperature (m.r.t.), equivalent to scalar illumination, and vector radiant temperature (v.r.t.), equivalent to illumination vector. The m.r.t. affects the warmth of environment; the v.r.t. affects the perceived asymmetry. The thermal radiation from lights increases the m.r.t. and v.r.t. Measurements on several lamp types have shown that the thermal radiation may be predicted from illuminance and lamp type. The radiation field in a building is modified by the structure: if the lamps are installed below a non-ventilated ceiling, the m.r.t. and v.r.t. will be increased; if cool air is introduced through the ceiling, the thermal radiation will be reduced. Some measurements in buildings are quoted.