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RE: [EnergyPlus_Support] PlantFlowResolver error -- "Branch flow rates out of bounds"

Check that the hot water coils are on a plant loop branch with "ACTIVE"
control and that there is a bypass in parallel with them.  

 

________________________________

From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of josh_miarch
Sent: Saturday, February 02, 2008 4:57 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] PlantFlowResolver error -- "Branch flow
rates out of bounds"

 

I'm attempting to simulate a large, multizone building, and I'm
encountering the following warning message:

** Warning ** PlantFlowResolver: Branch flow rates out of bounds, for 
Plant Loop=PLANT, Branch=514_COMPUTER_FC_HEATING_COIL_BRANCH
** ~~~ ** Conditions should be: 0.000 <= 1.517E-002 <= 0.000

Over the course of an annual simulation, there are enough of these
warnings (>30 000) to result in a fatal error that crashes the
simulation.

The branch in question is the heating coil branch for a
PACKAGEDTERMINAL:AIRCONDITIONER object. Both the coil and the
PACKAGEDTERMINAL:AIRCONDITIONER are available when these warnings are
occurring. 

I've noticed that this error tends to occur largely in the shoulder
seasons, when there is a relatively large amount of heating required
in the morning (as there are relatively low external temperatures, and
the zone thermostat switches from the the night set-back temperature
of 16 C to 20 C), and then cooling required later in the day (as the
combination of higher exterior temperatures and high internal gains
adds heat to the zone). Although the load on the heating coil is
relatively large in the morning and the PTAC object doesn't have a
field for specifying max HW flowrates, the flow that I am seeing to
coil is definitely reasonable, which makes this error more perplexing...

Any help would be greatly appreciated.

Josh

 



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