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# Humidity control makes OS simulation fail

When I put humidity control into HVAC air side network, any kind of humidity control makes simulation fail. And I tried to fix this problem, but still no way. Humidity setpoint does not show as an icon in the airloop network (fig 1), it simply disapered, but it's properties apper on the left pane - then simulation fail, there is no way to delete this setpoint control.

In case replacing humidity setpoint by a temperature setpoint (drop to the same node), I got both properties for temperature and humidity on the left, simulation fail too (fig 2)

Only way to fix this condition is to delete whole airside and rebuild, oh yes, rebuild :)

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Fix this condition by deleting zone and re-drop into network without humidity control is faster way.

( 2015-09-28 22:28:53 -0500 )edit

no one see this error when doing simulation ? :o

( 2015-10-02 11:27:19 -0500 )edit

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For humidity control to work, you need three things:

1. A ZoneControl:Humidistat object which references a humidity set point schedule with schedule type set to 'Percent'. In OpenStudio, the humidistat is assigned to individual zones on the Zone tab, similar to a temperature setpoint. Alternatively, you can do this via a measure for a constant setpoint schedule with the following:

humidify_sch = OpenStudio::Model::ScheduleConstant.new(model)
humidify_sch.setValue(humsetpt.to_f)
humidistat = OpenStudio::Model::ZoneControlHumidistat.new(model)
humidistat.setHumidifyingRelativeHumiditySetpointSchedule(humidify_sch)
zone.setZoneControlHumidistat(humidistat)

2. A humidity SetpointManager (of whatever type you need, available types listed here). It looks like you want a SetpointManager:Multizone:Humidity:Minimum. For this SetpointManager, you only need to apply a humidifying schedule in Step 1 - if you wanted both humidification and dehumidification, you would need two setpoints, and the corresponding SetpointManager. The SetpointManager is then placed on the outlet node of the component in your air loop that will do the humidifying/dehumidifying (not on the outlet node of the zone air terminal, as you have in your images).

3. Finally, you need to set the controller for your humidifying/dehumidifying component, let's say a cooling coil, to tell the component that it is controlling for humidity. To do this, change the 'Control Variable' in the Controller:WaterCoil to 'HumidityRatio' or 'TemperatureAndHumidityRatio' (also make sure 'Sensor Node Name' points to the node where the SetpointManager is placed):

Finally, the SetpointManager icons not showing up is a known issue, and will hopefully be resolved soon. Until then, be careful placing them, and save often!

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thanks a lot ! it works like a charm :)

( 2015-10-04 21:22:07 -0500 )edit

( 2017-04-11 05:57:27 -0500 )edit