AirLoopHVAC Outdoor Air System does not reach its maximum flow Rate
Hello guys,
I am tring to model a system on OS with two diferent configurations, so I have two different models.
My first model has an Outdoor Air System set to operate as an economizer. So my ideia is to let outdoor air in the zone when the outdoor air is both below DBT of 17ºC and RH of 80%. My system is like Picture 1 and my result for outdoor air mass flow rate looks like Picture 2.
That looks pretty reasonable to me.
My second model has an Outdoor Air System set to operate as an economizer. So my ideia is to let outdoor air in the zone when the outdoor air is both below DBT of 23ºC and RH of 80%. My system is like Picture 3 and my result for outdoor air mass flow rate looks like Picture 4.
At a first look, seems like to be okay. Happens that when I plot both graphs together, I get Picture 5.
That last picture concerns me a lot because I set both systems to a Maximum Outdoor Air Flow rate of 0.9 m/s and for the first model the OA Air Flow gets as high as 1 kg/s and for the second model the OA Air Flow gets to a limit of about 0.5 kg/s (and for me there is no reason for that).
I tried to change pretty much all variables and I did not see any change in results of the second model.
Does anyone know what may I be missing here?
Appreciate any advices here.
Thanks in advance.
As you helped me with my other post, any idea on how to fix this? @Keigo
You hardsized Maximum Outdoor Air Flow Rate in Controller:OutdoorAir. What about the Air Flow Rates in your AirTerminal, Fan and Cooling coil? Are they also hardsized? Or are they autosized unexpectedly low?
Air terminal has autosized values for "Maximum Air Flow Rate. Fan,.Cooling Coil and Outdoor Air System have hardsized values set for the Flow Rate (and also the same value of 0.9 m3/s). Is the problem related to the Air Terminal be set as autosized?
not sure. you can check the autosized flow rate.