Natural ventilation of parking garages : dimensioning of ventilation units with the assistance of air flow models.

Parking garages require ventilation because the exhaust fumes produced by the vehicles have to be discharged. This can be achieved with a mechanical or a natural ventilation system. A natural ventilation system has several important advantages compared with a mechanical system. As a rule natural ventilation systems arc simpler, cheaper and have fewer breakdowns, furthermore a natural system requires less maintenance and uses no energy (for air transfer). For the dimensioning of the necessary ventilation units in a parking garage, the calculating regulations (for The Netherlands) are given in NPR 2443 "parkeergarages". Recently the department of indoor environment, building physics and systems of TNO Building and Construction Research has carried out further investigations regarding naturally ventilated parking garages. Using a multi cell ventilation model research has been carried out to check if enough natural ventilation can be maintained, while the regulations according to NPR 2443 are not precisely taken into account. In this article one of these investigations will be discussed. This concerns an investigation by which also the airflow (concentration distribution) is investigated with a so called CFD Model, which stands for Computational Fluid Dynamics.