Ideal Loads Air System default mechanical ventilation setting

Hi all,

I am wondering what is the default setup for mechanical ventilation when using the Ideal Loads Air System in HB (how is the outdoor air flow rate calculated?).

The .idf contains the following:

DesignSpecification:OutdoorAir,
   zone_1OutdoorAirCntrl,                    !- Name
   Sum,        !- Outdoor Air Method
   0.0,          !- Outdoor Air Flow per Person {m3/s-person}
   0.0,          !- Outdoor Air Flow per Zone Floor Area {m3/s-m2}
   , !- Outdoor Air Flow per Zone {m3/s}
   , !- Outdoor Air Flow Air Changes per Hour {1/hr}
   ; !- Outdoor Air Flow Rate Fraction Schedule Name

Which made me think there was no outdoor air flow. But I guess I am wrong !

Thanks a lot for your help,

Marc

Replies are closed for this discussion.

Replies to This Discussion

Permalink Reply by Chris Mackey on June 26, 2016 at 4:58pm

Marc,

The 'Sum' value means that:

zoneVentilation = (ventilationPerArea x zoneFloorArea) + (ventilationPerPerson x occupancySchedVal x occupancyLoad)

This summing is what ASHRAE recommends. For more information, see the EnergyPlus reference:

http://bigladdersoftware.com/epx/docs/8-3/input-output-reference/gr...

-Chris

Permalink Reply by Marc Lotteau on June 27, 2016 at 12:51am

Chris,

Thanks a lot for your answer.

I'm ok with the meaning of 'Sum' value. So you confirm that default setup for mechanical ventilation is 'no mechanical ventilation' when using the Ideal Lodas Air System in HB ? (Outdoor Air Flow per Person = 0 AND Outdoor Air Flow per Zone Floor Area = 0).

I still have doubts, because when adding "Zone sensible Heating Rate" as output, I get non-null results. (I thought "Zone Sensible Heating Rate" was directly related to the Outdoor Air Flow)

Marc

Permalink Reply by Chris Mackey on June 27, 2016 at 6:13am

The default is not 0. It is set by the zone program. Use the readMe! Output of the "Set Zone Loads" component to see your Jones's ventilation specifications.

Sensible heating is pretty much the same as normal heating in an ideal air loads system. It's dependent on ventilation as well as everything else.

-Chris

RSS