Dear community, I hope all of you are doing well and thank you for reading my question, any support is greatly appreciated!
I'm using EnergyPlus 24.20 and I'm having trouble with the mechanical ventilation. I have two versions of model, let's call them v1 and v2. v1 works well and v2 is the one that has problems. THE ONLY DIFFERENCE BETWEEN V1 & V2 IS CHANGING DESIGNSPECIFICATION: OUTDOORAIR to DESIGNSPECIFICATION: OUTDOORAIR: SPACELIST.
In my model, there are 68 spaces of 11 different space types, for example, corridor space, open office space, etc., and there are 27 thermal zones in total (including 3 plenum zones).
In model v1, when I was modeling mechanical ventilation, I simply created 24 DesignSpecification: OutdoorAir objects for every thermal zone (excluding plenums). Each object has the same outdoor air flow per zone floor area 0.0004318, which is adopted from prototype building model, and are referenced in Controller: MechanicalVentilation. The output was as expected. The name of each DesignSpecification: OutdoorAir is [Name of Thermal Zone]_DSOA, for example, grd_east_zone_DSOA.
For V2, I tried to update the DSOA to be more specific to each space type since ASHRAE standard recommended different space type should have different ventilation rate. To model this, I first created 11 DesignSpecification: OutdoorAir objects for each space type, each object has respective outdoor air flow per zone floor area and outdoor air flow per person, and the outdoor air method is Sum. In model 2, the name of DesignSpecification: OutdoorAir object is [space_type]_DSOA, for example, openoff_space_DSOA. After adding space specific DSOA objects, I created 24 DesignSpecification: OutdoorAir: SpaceList objects, namely one SpaceList object for one thermal zone. For one SpaceList object, the spaces within this thermal zone and corresponding DSOA for this space type are included. To keep it consistent, I name each SpaceList object the same as v1, namely in this format: [Name of Thermal Zone]_DSOA. To help you understand, here is an example of one SpaceList object:
"Ground East Zone includes a closed office space and a conference space, the fields are: - Name: grd_east_zone_DSOA, - Space 1 Name: grd_closedoffE - Space 1 DSOA Object Name: closedoff_space_DSOA, - Space 2 Name: grd_conferenceE - Space 2 DSOA Object Name: conference_space_DSOA."
After I run the simulation, I plotted the time series results and found that the outdoor air is provided only when economizers are working, there is 0 outdoor air for ventilation, the requested mechanical ventilation for each air system is 0. I have demand control ventilation in both of my models, in model 2, the outdoor air limiting factor is never in DCV mode. But in model 1, everything works as expected.
To figure our the problem, I changed the DesignSpecification: OutdoorAir objects in model 2 to be the same as the DesignSpecification: OutdoorAir in model 1, namely I changed the outdoor air method field back to outdoor air flow per zone floor area, and the air flow per zone floor area back to 0.0004318, and changed the outdoor air flow per person back to 0. I expected that I can see the same result as v1 by doing this. However, I still got no mechanical ventilation as before. Therefore, I assume that I might have some misunderstanding in using DesignSpecification: OutdoorAir: SpaceList and would like to ask help from all you experts.
I'm really confused since I didn't change anything other than the DSOA objects. Again, I really appreciate any help and support, and it is my great pleasure to learn from you!
