Humidity setpoint managers not appearing in airloop

asked 2019-01-25 13:20:19 -0600

jmbattis gravatar image

updated 2019-01-25 14:13:57 -0600

I've been having trouble with single zone dehumidification. When I place the Setpoint Manager Single Zone Humidity Maximum (or any humidity-related setpoint manager for that matter), the icon does not actually appear. When I click on the the intended node, however, it does seem to have been included in some capacity (see the attached picture). Is this enough for it to be functional?

Additionally, since adding this loop, my model has been failing due to the following error. Can this be related to my humidistat or something else altogether (note: this space has no actual OA requirement or temperature setpoint):

   ** Severe  ** CalcMixedAirSetPoint: Missing reference temperature setpoint for Mixed Air Setpoint Manager NODE 64 OS DEFAULT SPM
   **   ~~~   ** Node Referenced =NODE 57
   **   ~~~   **   use an additional Setpoint Manager with Control Variable = "Temperature" to establish a setpoint at this node.
   ** Severe  ** CalcMixedAirSetPoint: Missing reference temperature setpoint for Mixed Air Setpoint Manager NODE 63 OS DEFAULT SPM
   **   ~~~   ** Node Referenced =NODE 57
   **   ~~~   **   use an additional Setpoint Manager with Control Variable = "Temperature" to establish a setpoint at this node.
   **  Fatal  ** Previous severe set point errors cause program termination

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Comments

The icon has not been visible for many OS versions. It is one of the known issues that are being corrected. However, the setpoints are accounted for during the simulation.

For the other issue, if you are using cooling coil for de-humidification, you may have to set the control variable in under cooling coil to TemperatureandHumidityRatio option. Please note that this would mean you have to have a setpoint manager for deck temperature and humidity. This is probably the reason for your setpoint missing error. Let me know if it works.

akr gravatar imageakr ( 2019-02-05 15:56:56 -0600 )edit

Thanks for the info regarding the icon.

That sounds like a reasonable solution. I think in my case the problem lies in the way the space is being conditioned. It's an unoccupied zone with a large exhaust requirement, but no heating our cooling requirement. I am simply dehumidifying to prevent condensation on equipment any cooling that occurs would just be a byproduct of dehumidification and reheat (at least for comfort purposes) is unnecessary. I suppose I could select a deck temperature per your advice; however, it would be arbitrary.

jmbattis gravatar imagejmbattis ( 2019-02-07 08:02:00 -0600 )edit