Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
These max iteration warnings are very hard to diagnose. You have a very simple air loop defined. I see that you are using air flow network and I suspect this is the root of the warnings. I disabled air flow network by changing the AirflowNetwork:SimulationControl input for AirflowNetwork control to NoMultizoneOrDistribution and the max iteration warnings are gone.
************* EnergyPlus Completed Successfully-- 15 Warning; 0 Severe Errors; Elapsed Time=00hr 00min 4.47sec
Changing the control input back to MultizoneWithDistribution causes the max iteration warnings.
** Warning ** SimHVAC: Maximum iterations (20) exceeded for all HVAC loops, at AXON CFD ANALYSIS (01-01:31-12), 01/02 05:00 - 06:00
** ~~~ ** The solution for one or more of the Air Loop HVAC systems did not appear to converge
** ~~~ ** ...use Output:Diagnostics,DisplayExtraWarnings; to show more details on each max iteration exceeded.
** Warning ** SimHVAC: Maximum iterations (20) exceeded for all HVAC loops, at AXON CFD ANALYSIS (01-01:31-12), 01/02 05:00 - 05:05
** ~~~ ** The solution for one or more of the Air Loop HVAC systems did not appear to converge
** Severe ** PsyRhoAirFnPbTdbW: RhoAir (Density of Air) is calculated <= 0 [-1.61928].
** ~~~ ** pb =[-130808.27], tdb=[7.42], w=[1.9966870E-003].
************* EnergyPlus Terminated--Fatal Error Detected. 15 Warning; 1 Severe Errors; Elapsed Time=00hr 00min 3.12sec
I suggest adding more Output:Variable reports to show how the simulation is proceeding up to the point where the fatal occurs to see if you can identify anything wrong with your inputs. Your goal is to find reasons for the severe error:
** Severe ** PsyRhoAirFnPbTdbW: RhoAir (Density of Air) is calculated <= 0 [-1.61928].
** ~~~ ** pb =[-130808.27], tdb=[7.42], w=[1.9966870E-003].
** ~~~ ** Routine=Unknown, Environment=AXON CFD ANALYSIS (01-01:31-12), at Simulation time=01/02 05:00 - 05:05
If you cannot find a reason for this issue then I suggest posting your question and input file on the HelpDesk and note that you are using AirFlowNetwork so that the AFN expert can respond. See http://energyplus.helpserve.com or send a message to energyplus-support@gard.com.
