Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
The standard (non-airflownetwork) EnergyPlus HVAC simulation does not use node pressures to determine flow. Pressure is only used for pyschrometric calculations. Air node pressures are initialized to to the outdoor barometric pressure at the beginning of each new environment. Looking at timestep output reveals that some nodes remain fixed at this intial value (e.g. Zone Air Nodes and the return path nodes), the outdoor air nodes track the current barometric pressure from the weather data, and the air system nodes are a mix of these two pressures. A new issue has been posted to review this, but the impact on property calculations should be minor. https://github.com/NREL/EnergyPlus/issues/5547
