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AHU Humidity Control

asked 2016-08-08 11:08:03 -0600

Dustin gravatar image

updated 2017-05-03 21:46:12 -0600

I am having some trouble knowing what I should be doing to model this AHU in a building that has humidity control. From my understanding, there is a limit on the supply air humidity ratio (SAH) and a setpoint on the return air humidity ratio(RAH) at the AHU level and not at the zone level. I understand that I can put in the SAH in my energy model with one of the setpoint managers, HumidityMaximum I believe. Then comes my confusion, for humidification and de-humidification in energy plus there has to be a ZoneControl:Humidistat which would require a humidifying and de-humidifying schedule applied to each of the zones. What values should I be using for those two schedules is where I am stuck.

If anyone has an input that would be great. I have done some digging and came across link text and link text which have helped me understand what is required to control humidity.

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there is an existing user voice item related to this, see

Archmage gravatar image Archmage  ( 2016-08-15 14:52:03 -0600 )edit

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answered 2016-08-15 10:16:38 -0600

Rohini gravatar image

I normally put a dehumidifying schedule at the ZoneControl:Humidistat level. The value I use is 50-60%. On the AHU side (if it is a unitary system object), you will need to specify the type of latent load control (only when sensible load is available etc.), and dehumidification control type (none, coolreheat, etc.). For humidity schedule, I just put in 30% schedule. This will come into effect only if you have a humidification object.

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Asked: 2016-08-08 11:08:03 -0600

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Last updated: Jan 27 '17