Return Fan for Packaged VAV

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Hello all,

I am trying to model the baseline of a building with System 5
Packaged VAV with DX cooling and Hot Water Fossil Fuel Boiler heating.
Appendix G also says that return fans should also be modeled in the
baseline. My problem is that I am not sure how to input the return
fans into Equest. Following Appendix G, I have been modeling the air
handling units, that have return fans associated with them and no
heating, as Packaged VAV (no heating type system). However, this
system type does not allow me to add the return fans. What are you
suggestions to add the return fans into the model? Or am I specifying
the incorrect system? The zone is a large server room that is has a
supplied by 4 large AHUs and have 4 large return fans. The large AHUs
are actually fan wall, 11 fans combined, that only cool a large server
space. Thanks for the help.

Regards
Justin

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Justin,

I'm not sure why you are having trouble adding return fans. Both the
PVAVS and VAVS system types allow them to be added in the "Fan Power and
Control" tab. If you are modifying an existing system and the fields are
grayed out, try creating a new system of type PVAVS or VAVS and you
should be okay. You should also consider whether or not the server room
should be modeled instead as System type 3 or 4, per the exceptions to
G3.1.1. Computer server rooms are specifically mentioned as an example.

Regards,

William Bishop, PE, BEMP, LEED(r) AP

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