Error in Fresh Air Handling Unit
After assigning 32 Fan Coil Units and 3 Fresh Air Handling Units with COPs, simulation is giving error for FAHUs. It says:
- Too many zone mixers in Return Air Path=FAHU1 DEMAND SIDE RETURN PATH
- Too many zone mixers in Return Air Path=FAHU2 DEMAND SIDE RETURN PATH
- Too many zone mixers in Return Air Path=FAHU3 DEMAND SIDE RETURN PATH
- Return air Path(s) did not pass integrity testing
What is the solution to this? Because 8 zones are assigned to FAHU1, 8 to FAHU2 and 12 to FAHU3.
I suspect you have (wrongly) more than one mixer on the demand side of your airloopHVACs, but without seeing the related portion of your IDF, there's hardly a way to help.
What do you mean by mixers? You mean the exhaust air fan?
AirLoopHVAC:ZoneMixerWhere is it in FAHU visually?
I mean the AirLoopHVAC:ZoneMixer like @adhilton said. Again, without seeing the IDF file (the IDF generated by design builder, not the design builder file, I don't have a license myself), hard to help. Maybe a designbuilder user could help with the DB file though.
Here's the link to the IDF file of my simulation.
https://1drv.ms/u/s!Ase9DtM9ZxGyjAruk...
@adhilton
@Julien Marrec I checked in the IDF file. Yes there are more than one mixers. But one FAHU is serving more than one zones. So won't it definitely have more than one mixers too?
Your AirLoopHVACs are ill-formed indeed, "FAHU1 1 Demand Side Return Path" has 7 mixers (circa line 49336). You should expect to have one splitter and one mixer per loop. I can't tell you what you did "wrong" in DesignBuilder to obtain this though...
The splitter serves several branches (one per zone), and the mixer mixes them back. Similar to this image basically.
@Julien Marrec . Yes I have assigned them by adding several splitters to the FAHUs. Here are the images: https://1drv.ms/f/s!Ase9DtM9ZxGyjAu47... . What do you think should be the solution?