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BEOpt: Abandoned ductwork when replacing with MSHPs

asked 2018-09-16 13:19:39 -0500

muhl gravatar image

updated 2018-09-17 07:16:07 -0500

I set up Existing and My Design systems in BEOpt in multifamily (2 unit) properties. BEOpt does not "run", showing several errors ([one error noted here] (https://unmethours.com/question/34244....

Does BEOpt appropriately avoid using existing ductwork in "My Design" if the next HVAC doesn't require it? For example, when an existing furnace is replaced with mini-split heat pumps. Does running the EnergyPlus models in the most updated version (v8.9) fix any of these problems?

Error log below: 9/16/2018 2:00 PM: 1.xml: Warning: Mini-split heat pumps are not simulated with back-up electric resistance heaters. Consider adding an Electric Baseboard heater, if desired. 9/16/2018 2:00 PM: 1.xml: Warning: Ductless mini-split heat pump selected but ducts were selected. The duct system will be ignored. 9/16/2018 2:00 PM: 1.xml: Traceback (most recent call last): 9/16/2018 2:00 PM: 1.xml: File "C:\Program Files (x86)\NREL\BEopt_2.8.0\Modeling\energyplus.py", line 13803, in <module> 9/16/2018 2:00 PM: 1.xml: y = EnergyPlusInput(xmlfile, cost_file=sys.argv[3]) 9/16/2018 2:00 PM: 1.xml: File "C:\Program Files (x86)\NREL\BEopt_2.8.0\Modeling\energyplus.py", line 41, in __init__ 9/16/2018 2:00 PM: 1.xml: sim.process(cost_file) 9/16/2018 2:00 PM: 1.xml: File "C:\Program Files (x86)\NREL\BEopt_2.8.0\Modeling\sim.py", line 1397, in process 9/16/2018 2:00 PM: 1.xml: self._processSystemSizing(geometry, unit, weather) 9/16/2018 2:00 PM: 1.xml: File "C:\Program Files (x86)\NREL\BEopt_2.8.0\Modeling\sim.py", line 10097, in _processSystemSizing 9/16/2018 2:00 PM: 1.xml: unit.systemsizing = sizing.SystemSizing(self, geometry, unit, weather) 9/16/2018 2:00 PM: 1.xml: File "C:\Program Files (x86)\NREL\BEopt_2.8.0\Modeling\sizing.py", line 33, in __init__ 9/16/2018 2:00 PM: 1.xml: self._process(sim, geometry, unit, weather) 9/16/2018 2:00 PM: 1.xml: File "C:\Program Files (x86)\NREL\BEopt_2.8.0\Modeling\sizing.py", line 110, in _process 9/16/2018 2:00 PM: 1.xml: self._processCoolingEquipmentAdjustments(sim, mj8, unit, weather) 9/16/2018 2:00 PM: 1.xml: File "C:\Program Files (x86)\NREL\BEopt_2.8.0\Modeling\sizing.py", line 2073, in _processCoolingEquipmentAdjustments 9/16/2018 2:00 PM: 1.xml: coefficients[4] * units.F2C(mj8.EnteringTemp) * 2 + \ 9/16/2018 2:00 PM: 1.xml: TypeError: 'float' object has no attribute '__getitem__' 9/16/2018 2:00 PM: 2.xml: Warning: Mini-split heat pumps are not simulated with back-up electric resistance heaters. Consider adding an Electric Baseboard heater, if desired. 9/16/2018 2:00 PM: 2.xml: Warning: Ductless mini-split heat pump selected but ducts were selected. The duct system will be ignored. 9/16/2018 2:00 PM: 2.xml: Traceback (most recent call last): 9/16/2018 2:00 PM: 2.xml ... (more)

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answered 2018-09-17 10:48:53 -0500

Yes, BEopt appropriately avoids using existing ductwork when an existing furnace is replaced with mini-split heat pumps, as explained by the:

Warning: Ductless mini-split heat pump selected but ducts were selected. The duct system will be ignored.

The TypeError looks unrelated and I suggest addressing that in your other posted Question.

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Thanks Eric. I did see the Warning notation and it seems explicit. My concern remained because I continue to see error messages like the following, which seems potentially related to ductwork and the shift from one system to another.

1.xml: Error: * Severe * GetZoneEquipmentData1: ZoneHVAC:EquipmentList = UNFINISHEDBASEMENT ZONE EQUIPMENT 9/17/2018 11:59 AM: 1.xml: Error: * ~~~ * ...multiple assignments for Zone Equipment Cooling Sequence=1, must be 1-1 correspondence between sequence assignments and number of equipments.

muhl gravatar imagemuhl ( 2018-09-17 11:06:39 -0500 )edit

Can you send your project file to beopt@nrel.gov?

shorowit gravatar imageshorowit ( 2018-09-17 11:09:15 -0500 )edit

Sent! I included two project files that seem to experience similar issues.

muhl gravatar imagemuhl ( 2018-09-18 00:52:49 -0500 )edit

I just ran both projects using the fixed energyplus.py from the other thread and they both ran successfully. Looks like that was the only issue.

shorowit gravatar imageshorowit ( 2018-09-18 10:09:49 -0500 )edit

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Asked: 2018-09-16 13:19:39 -0500

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