Air and Heat Flow through Large Vertical Openings

摘要

After a short description of the physical phenomena involved, unified expressions are worked out describing net airflow and netrnheat flow through large vertical openings between stratified zones. These formulae are based on those of Cockroft forrnbidirectional flow, but are more general in the sense that they apply to situations of unidirectional flow as well. The expressionsrnare compatible with a pressure network description for multizone modelling of airflow in buildings. The technique has beenrnincorporated in the flows solver of the ESP-r building and plant energy simulation environment.rnThe relative importance of the governing variables (pressure difference, temperature difference and vertical air temperaturerngradients) is demonstrated by parametric analysis of energy performance in a typical building context. It is concluded thatrnvertical air temperature gradients have a major influence on the heat transferred through large openings in buildings andrnshould be included in building energy simulation models.