Ventilation and stratification in naturally ventilated spaces driven by heated internal vertical surfaces.

This paper reports on research into the fundamental fluid mechanics mechanisms that lead to thermal stratification in a naturally ventilated room containing sources of heat, or cooling. This aspect of natural ventilation has an important influence on both air exchange rates and thermal comfort in a naturally ventilated space. Particular attention is paid to the situation where the major source of heat is a vertical surface, such as a wall heated by solar insolation, for example. A theoretical model is presented that allows prediction of the ventilation flow stratification in such a room for the first time. Numerical results from this model and some preliminary experimental validation tests are presented. An example of how this theoretical model might be used by a designer for design of a naturally ventilated space subject to major heat gains at vertical surfaces is discussed.