Terminal not sized error

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All,

I am working on a project which has AHUs supplying via series fan powered boxes. I am trying to model this using "Powered Induction Unit". I am getting this error which I am unable to understand. It says, "terminal is not sized, but its air handler is sized. In this case, the terminal must also be sized. Check design-day criteria, or manually size the terminal." Can somebody please point out what I am missing here? Your help is greatly appreciated.

[cid:image002.jpg at 01D9D79D.E957C120]

Thanks,
Pramod

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Without looking at your model it is hard to tell, but this error sounds distantly familiar; I think if you are missing airflow sizing info in your thermal zone.

_______________________________________________
Ethan Seaman
Sustainable Design Analyst
SMMA
t: 617.520.9288
www.smma.com

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Ethan,

Thanks for your reply. The weather file was causing the issue. I changed it and it is working now. Appreciate your help.

Thanks,
Pramod

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Ethan,

I cleared the error by providing airflows at zone level. Now I am getting abnormal simulation errors. I cleared it initially by changing the weather file but now I am getting the same error if I give series terminals at zone level. It works for parallel terminals but, while simulating it shows simulations aborted for heating design days. Do you think my schedule or AHU data has issues? I want to use series fan powered VAVs at zone level. I have attached eQuest files for your reference.
I understand that this MsgBomb call is for Series terminal, but I am not able to find where the issue is. Your help is greatly appreciated.

[cid:image003.jpg at 01D9DAAE.AAE43EF0]

Thanks,
Pramod

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Pramod,
The only thing you changed is the weather file? Are you also using design days?
Thanks,
~Bill

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Pramod,

When I?ve seen this error, I believe it was due a space not having any net cooling or heating load during the LOADS routine, so the terminal unit serving the space cannot be sized. I?d recommend checking your LS-A and LS-B reports for the space in question.

Michael Weller
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Energy Modeling Lead

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Pramod,

MsgBomb errors are annoying as they're not upfront about what's causing them. There's a document available on Doe2.com to help; I've attached the link to it below.

This shows the error is coming from the terminal unit / VAV box presumably that's located in the zone. The error is with how it's being sized.
[cid:image001.png at 01D9DA75.311C3020]

When I opened your model I noticed you have 2 AHUs (CHW+HW) that are set to system type: single zone reheat. My understanding is this is not a ventilation system type, but you have zones under that system calling for outside air. That could be causing some issue with how the program simulates the terminal units.

I set those 2 AHUs (1&4) to VAV systems, and also added OA ratios (I specified 100% OA but this may not be the case so double check). The model now successfully completes the simulation (model files attached).

I also added heating and cooling design days. I can't recommend this step enough for all projects, but especially this one; this is a pretty big model and the simulating of design days takes up a big chunk of your simulation time.

https://doe2.com/Download/DOE-23/MSGbomb_ContentAndLocation_Information.pdf
_______________________________________________
Ethan Seaman
Sustainable Design Analyst
SMMA
t: 617.520.9288
www.smma.com

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