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How to get the damper positions for the outdoor air in packaged rooftop unit ?

asked 2019-09-06 16:50:56 -0600

Archan Shah gravatar image

updated 2019-09-10 17:33:05 -0600

I have been trying to model the medium office building in Energyplus and I have added an Packaged rooftop unit for a VAV system with Reheat. I want to know the damper position in the packaged rooftop unit for outdoor air and return air. I have been using this

Output:Variable,*,Air System Outdoor Air Flow Fraction,Timestep;

for getting the system outdoor air flow fraction. But I don't think this represents the damper position ( Does it represent damper position ?) . I am not interested in knowing the zone level damper position but only want to know the outdoor and return damper positions.

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By damper position do you mean open/closed or the outdoor airflow?

Luis Lara gravatar imageLuis Lara ( 2019-09-09 12:54:16 -0600 )edit

I mean to ask about open / close of the damper.

Archan Shah gravatar imageArchan Shah ( 2019-09-09 13:10:09 -0600 )edit

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answered 2019-09-10 10:02:52 -0600

You can use the Air System Outdoor Air Flow Fraction variable. If it is zero, there is no outdoor air and the damper is closed. If it is anything other than zero, the damper is open.

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Thanks Luis ! So, if the Air system Outdoor Air Flow fraction is 0.33 means that the damper is open 33 % w.r.t closed damper ?

Archan Shah gravatar imageArchan Shah ( 2019-09-14 22:57:30 -0600 )edit

Hello Archan, no. The Air System Outdoor Air Flow Fraction variable reports the ratio of OA air to total supply air. So, if your during a specific timestep your Airloop supply air is 1000 cfm, with an Air System Outdoor Air Flow Fraction of 0.33 you will have an average of 333 cfm of OA and 666 cfm of recirculated air during the reported timestep. You can check the details of the variable in the I/O reference here.

Luis Lara gravatar imageLuis Lara ( 2019-09-16 11:39:30 -0600 )edit

Thanks Luis !! I appreciate it !

Archan Shah gravatar imageArchan Shah ( 2019-09-18 11:31:16 -0600 )edit

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Asked: 2019-09-06 16:50:56 -0600

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Last updated: Sep 10 '19