Definitions for different types of air densities

[Sebastian Spürk]

Hi,

I am looking for definitions or formulas that explain the different types of air densities used in ventsim, such as: air density, air density (apperent), air density mid entry/exit.

 

Regards

Sebastian

[Martin Griffith]

Hi Sebastian,

In Ventsim, it is sometimes useful to work with the true density or the apparent density, the difference being that the apparent density is the weight of air per unit volume of dry air, excluding the moisture in the air.

Air density is the weight of moist air per unit volume, usually in units of (kg of moist air)/m3

Apparent air density is the weight of dry air per unit volume, usually in units of (kg of dry air)/m3

The terms Mid Entry/ Exit, inlet and outlet refer to the position on the airway where the data is from. A datum at the inlet of the airway is denoted "Inlet", at the outlet of the airway, "Outlet", immediately before wherever the icon is on an airway, "Mid In", and immediately after wherever the icon is on an airway, "Mid Out".

You can shift the data in the Ventsim viewer between these 4 positions using the buttons at the bottom left of the Ventsim window: