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Fan coil unit parameters simulation problem.

asked 2018-10-12 04:56:04 -0500

colinchen4 gravatar image

updated 2018-10-31 21:59:08 -0500

I am setting up a Openstudio proposed building model with DOAS and fan coil units according to previous question

All the parameters for the fan coil unit are all set up according to the designed sechdule. There is one of the fan coil cooling coil setting, which is showed in the following picture.image description The err shows the following lines: image description

Here are linkes for the folder and the OSM file for this model.

https://drive.google.com/open?id=1Idi...

https://drive.google.com/open?id=16XF...

Thanks in advance! I have tried my best to solve this without any clue for two days...

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answered 2019-02-27 13:16:33 -0500

You have specified the coil rated parameters before you know what the actual coil load or entering air conditions are. I realize this seems counter-intuitive, but in EnergyPlus the design conditions are not really used as you would expect. When the water coil is sized it looks at the simulated coil entering air and water temps. The water temp is probably close to what you have specified here as long as the chilled water plant uses the same temperature. But the coil entering air temperature may be very different from what you have "hard-sized" here. You should set all these inputs to autosize and then look in the eio file for the results. Then compare those results with what you have entered here. You might then be able to use some of your inputs when considering the autosized value for each of these inputs. Alternately you might need to get the rated conditions for a different size coil and enter those.

Also, notice in the warnings that the water flow rate was changed for some coils. This is because the outlet water temperature calculated by the water coil model was higher than the entering air temperature entered here. It is very difficult to anticipate what the operating conditions of the coil will be before you simulate that coil in the building model.

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Thanks for answering. i realized there might be a lot of contradictions between the design drawings and the model settings. It would be better if there is an instruction for each inputs in energyplus. Big ladder's explainations sometimes seem ambiguous and confusing for me. In this case, i will try autosizing this model for most of the settings and come back to this later.

colinchen4 gravatar imagecolinchen4 ( 2019-02-27 21:40:28 -0500 )edit

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Asked: 2018-10-12 04:56:04 -0500

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Last updated: Feb 27