Abstract

Radiant ceiling heating system radiates heat to the surrounding surfaces including the cold interior surface of the window. The cold window surface, without heating system, loses heat via transmission to the cold outside. It can be caused thermal discomfort by downdraft. Downdraft is unwanted local cooling of the body caused by air movement. Therefore it is more likely to occur when air temperature is lower and air velocity is higher. The objective of this study is to find out the appropriate conditions of radiant ceiling heating system to prevent thermal discomfort by analyzing the indoor air temperature and air velocity distribution in office space. A computational model of a room with radiant ceiling heating system is constructed within the CFD program Star CCM+. Six cases of radiant ceiling heating system with varying surface temperatures, surface areas and window U-value are considered.