I have a system with VFD on the fan, central heating and cooling coils (no
reheat), and chilled water for cooling. Curious to see how others would
model this, or if I am missing something very obvious.
If I use VAV, even though there is central coil, it does not come on. The
heating seems to be only through the reheat coil. I could do the warmest
zone control, but I think this uses only return air, not heating coil for
the
If I use single zone reheat, cannot get the fan to be variable speed.
PVVVT might work (never tried it) but it does not use chilled water.
I could use a dual duct single fan and the min flows be zero fo both ducts?
Thanks
-Rohini
When using the VAV or PVAV system types the heating coil can be sized by
using the leaving air temperature conditions, but never turns on. The true
way to use a heating coil for a VAV is to call it a preheat coil, and
specify a leaving air temperature close to what you have in reality.
Occasionally, the reality is higher than what eQuest allows (something
like 70 degree F) and then you need to "fake" it by making up the rest of
the heating load in the reheat coils.
Hope this helps!
Rob H.
You say you have a system with VFD on the fan, central heating and cooling coils (no reheat). Why no reheat?