CoilSystemCoolingWaterHeatExchangerAssisted does not cool?
I experimented with a CoilSystemCoolingWaterHeatExchangerAssisted today. I wrote an openstudio-3.7.0 sdk python script (several, actually) to that end. I "simlpy" inserted the coil system in lieu of a CoilCoolingWater into a standard AirLoopHVAC, no other changes. The coil system has a HeatExchangerAirToAitSensibleAndLatent and obviously a CoilCoolingWater. Inspection of the resulting .OSM and .IDF files seems to indicate all is connected correctly, even though the icon showing up in the OpenStudioApp-1.7.0 HVAC editor in lieu of the CoilCoolingWater icon looks a little odd, almost like grayed out.
Be that as it may, the standard CoilCoolingWater yields the expected results, but the coil system instead looks like its cooling coil never gets activated - lots of unmet cooling hours. On the drive home, I thought, maybe the coil system doesn't belong in an AirLoopHVAC? Maybe it only works in an AirLoopHVACOutdoorAirSystem as an OA pretreater, rather than a SA handler?
The idea was to use the coil system as a wrap-around heat pipe coil. I also know that the HeatExchangerAirToAitSensibleAndLatent works when used in the AirLoopHVACOutdoorAirSystem to connect OA and EA streams, so maybe even when stuffed into the coil system, it wants to be part of an AirLoopHVACOutdoorAirSystem? I would welcome any thoughts on this.
If you create a CoilSystemCoolingWaterHeatExchangerAssisted and connect the CHW coil to a PlantLoop before adding the CoilSystem to an AirLoopHVAC, the ControllerWaterCoil object won't be connected correctly and the CoilSystem will not be controlled, as documented here: https://github.com/NREL/OpenStudio/is.... The workaround is to connect the CoilSystem to the AirLoopHVAC first, then add the coil to the PlantLoop.
Thank you very much, Eric Ringold! Yes, I did what you said and the ControllerWaterCoil does indeed show up now - nice! There also seems to be some chilled water usage now. However, the simulation now takes a very long time, and the results are only partial, with loads of "oscillation" warnings. I have a SetpointManagerWarmest on the supply outlet node of the AirLoopHVAC. Might I need another setpoint manager right after the coil system?