Natural ventilation design using loop equations.

The design of natural ventilation systems - the configuration and sizing of system components - assumes one of two generic forms: the nasty form based on thermal comfort criteria or the nice form based on specified airflow rates. The nasty form demands consideration of the complex coupled interaction of a building's airflow and thermal systems - a difficult and often intractable challenge. The nice form, on the other hand, is quite tractable, yet it is commonly approached using interactive and approximate techniques. This paper presents an 'exact' approach to the nice design problem based on pressure loop equations. It allows direct sizing of a variety of airflow components, unambiguous consideration of stack and wind driven airflows without simplifying approximations, and nontechnical constraints and operational strategies to be included in the design process.