OpenStudio: Outdoor Air Controls

asked 2017-03-16 17:07:18 -0500

cnutt gravatar image

updated 2017-03-18 08:42:55 -0500

I am modeling multifamily units that use a PTHP with a decoupled constant volume outdoor air fan. The outdoor air is always on except for an upper outdoor temperature limit at 100F and a lower limit at 20F. There is also an RH sensor mounted outdoors to shut the system off at >55% RH.

I'm having some troubles setting this up. I can get close but haven't figured out how to include all the set points.

If I include the OA on the PTHP then I don't have much control over the set points.

Using the "natural ventilation" component gets close and allows me to set max/min temperatures but does not address the humidity sensor. It also does not include the air on the outdoor air on the model results page.

It looked like I may be able to use a unit ventilator component but I'll have to set it so there is no heating or cooling, as there is no unconditioned component, but that also doesn't include RH, only enthalpy.

I tried to create the fan system in the system builder but it will not accept the humidity setpoint manager, though it will take the temperature setpoint managers.

The "follow OA temp" manager is close but it works off of humidity ratio rather than RH

Any suggestions on how I can make this work?

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