RE: [EnergyPlus_Support] AFN Node Pressure Distribution & Air Density

[Lixing Gu <gu@xxxxxxxxxxxx>]

My answers are under your questions.

1a) Where is the Zone_Node situated Floor/ceiling/center?

A: Center.

1b) Is there a link to the room-air-model (temperature at a specific height
- if not mixed air)?

A: No.

1c) could you please give the formuala for the zone 'AirflowNetwork Node
Total Pressure'? Especially how is the zone static pressure calculated?

A: The model uses the total pressure, The static pressure is not calculated
alone. The section of AirflowNetwork model in the Engineering Reference
provides detailed information.
 
2) For the calculation of the air density i used following formula, which
wasn't found in the eng.reference - but it gives slightly different results:

ρ=(P_atm (1+W_air))/(461,518(T_air+273,15)(W_air+0,62198))     [kg/m3]
ρ = Air density [kg/m3]
Patm = Outdoor barometric pressure at ground level [Pa]
Wair = Air humidity ratio [kgWater/kgAir]
Tair = Air Temperature [°C]

A: the following equation is used to calculate air density
      rhoair = pb/(287.d0*(tdb+KelvinConv)*(1.d0+1.6077687d0*w))

Lixing

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