IES-VE User Forum

Hi All,

While I'm editing System Parameters for Baseline HVAC System within Navigator ASHRAE 90.1 App.G I need to assign a value of PRM baseline fan-power adj 'A'. This parameter is defined by Ashrae 90.1 as a moltiplication of Pressure Drops and Design Supply Air Flow but I don't know know that value (CFMD) until I launch the Sizing Run so I can't do this calculation.
Am I doing right?? Is there another possibility to calculate that factor??

Thank you for your support!!

Best regards

This is why in the PRM navigator the Baseline fan power sizing is a separate step. You would need to do room sizing, and system sizing for the baseline, then look at your fan supply air flow and calculate "A", then go back to the baseline system parameters and input the A value you calculated, afterwards run the baseline fan power sizing step which is the last step of the sizing runs "Update Baseline fan sizing data"

1. "Import Systems" -->"90.1 PRM 2004 and 2007 baseline systems" --> choose which system compliance with ASHRAE 90.1 that you need
2. Fine tab "Systems Parameters" -->at cell "90.1 PRM Baseline System Pressure Drop Adjustment" fill _?_ Pa/in water that you calculated
3. Save/ Assign
4. "Sizing Runs"-->"Update Baseline fan sizing data"
5. Return "Edit Current Baseline" and review "Design total pressure"