I have an Equipment Rack Room (ERR) that has a chilled water/hot water
single zone system, with de-humidification and humidification. When i try
to model this, i enter in the appropriate inputs into the system and zone
levels, and then for humidification i enter in my design parameters, 60% and
35% with electric cansister humidifier type.

My problems begin now, when i run the model the humidifier is never turning
on throughout the year, and dehumidification seems to work just fine. Also
the program is currently sizing my cooling coil to a size much larger than
previously determined by hand.

More notes: the Rack load is 90kW with minimal other loads (lights and
people). 99% sensible heat ratio. Using this i need about 30 tons of
cooling, which translates to a coil that should be slightly larger than
that, due to de/humidification. my thermastat is set to 72deg and design
temperature is also 72 deg.

This has been alluding me for about 2 hours, so any help is appreciated.

--
Rob Hudson