Estimation of flow rates in naturally ventilated buildings using simplified method

A simplified design method has been derived for use in the estimation of the flow rates in naturally ventilated buildings. The method is based on a one-dimensional "loop analysis" in which the buoyancy forces are balanced by the pressure drops to due friction. Multiple zones, multiple floor buildings are catered for with each zone characterised by its internal gains and its discharge coefficients. Wind effects at the entrance and exits are also taken into account. The procedure yields the zone mass flow rates and temperatures directly by the solution of a simple cubic equation for each loop. Interaction between loops requires a few iterations. The procedure is straight forward and simple enough to be put on a Spreadsheet. This methodology allows the architect to explore various building configurations at little expense and hence to focus on those designs which warrant further detailed analysis using a full building simulation package. In this paper, the fundamental theory behind the loop analysis is described together with the first results at its validation using an emulation of the simple single stack PV cladding arrangement.