Performance analysis methods for passive downdraft HVAC systems

Passive Downdraft HVAC systems are natural ventilation systems that add heating and cooling to the passive airstream to control zone temperatures and enhance the flow of air by affecting buoyancy forces.  This paper reviews different analysis approaches used to study the performance of this HVAC approach. It investigates the use of bulk airflow modelling to test comfort performance and reviews results against operational performance of buildings that used that software in their design. The study notes that relatively robust comfort exists in existing buildings designed using similar analysis methods. It also identifies benefits and limitations to the use of more detailed analysis to measure energy consumption and further optimize and test performance.