Hi Michelle
The WPCs are related to True North.Â
The calculation of wind pressure coefficients depends on the direction of the wind. this is what creates the dependence on True North.Â
The idea of the WPCs is to create a pressure distribution over the building for each time step with the wind speed and direction from the weather file as the input variables.Â
I reckon that when you calculate the WPCs, do so with building north and true north aligned.
What I do not know is whether EnergyPlus will account for the building north and add this angle to relative direction from which the wind blows when calculating the pressure distribution. If it does, then it may suffice to calculate your WPCs once, and then rotate the building north for each of your cases...
The best way to find that out is to run a simple experiment.Â
hope that helps
TomÂ
Hello everyone, I have a doubt about the calculation of Wind pressure coefficients (WPC) in the Airflow Network group in EnergyPlus (natural ventilation modeling) when I use INPUT as a choice of wind pressure coefficient Type. I am using relative coordinate system and I intend to rotate my geometry for different orientations by changing the North Axis. So, I would like to know if the WPCs input is related to True North or Building North? Do I have to input different WPCs data for each orientation? Thank you very much, Michele RossiÂ