Why are some of my Coil:Cooling:Water objects autosizing to 0 capacity?

asked 2017-02-24 16:50:37 -0500

JustinLueker's avatar

updated 2017-03-01 13:00:16 -0500

I am modeling a building in EnergyPlus with 34 air handlers and associated cooling coils. Only 4 of the coils autosize to 0 capacity. See the error message below:

** Warning ** SizeWaterCoil: Potential issue with equipment sizing for Coil:Cooling:Water OP09_CC
**   ~~~   ** ...Rated Total Cooling Capacity = 0.00 [W]
**   ~~~   ** ...Air flow rate used for sizing = 0.00000 [m3/s]
**   ~~~   ** ...Outdoor air fraction used for sizing = 1.00
**   ~~~   ** ...Coil inlet air temperature used for sizing = 0.00 [C]
**   ~~~   ** ...Coil outlet air temperature used for sizing = 1.#IE-311 [C]

The zones fed by these units do indeed have cooling loads, and they are showing high unmet cooling hours. The strange thing is- I've modeled all 34 coils identically. I'm not sure why only these 4 are acting up.

Here is a sampling of some of my inputs that relate to these systems:

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I'd start looking at possible causes of ...Air flow rate used for sizing = 0.00000 [m3/s]

aparker's avatar aparker  ( 2017-02-24 16:59:25 -0500 )edit

Thanks for the note. I have tried hard-sizing the air/water flow rates and temperatures for the coils in question, but still seeing the same "0 cooling capacity" error messages. Any other suggestions to modify the air flow rate used for sizing?

JustinLueker's avatar JustinLueker  ( 2017-03-01 13:07:02 -0500 )edit

It's probably because you have no cooling load in the space that the coil is serving.

Adam Hilton's avatar Adam Hilton  ( 2017-03-01 17:08:19 -0500 )edit