[EnergyPlus_Support] Severe Geometry & Fatal Airflow Network Iterations Errors

["Kristin Field" <fieldkm@xxxxxxxxx>]

If anyone could help me with the following errors I've been 
receiving, I would be *very* grateful.

Background: My file, which I'll upload shortly (titled 
BAB_Baltimore_092306.idf), is supposed to represent a simple 30'x30' 
house that's 16' tall with a 4-sided, unconditioned attic on top (2 
triangles and 2 rectangles).  The attic peak is at 23.5'.  This house 
should have typical DX cooling and furnace heating, with natural 
ventilation when weather permits.  I have attempted to implement a 
simple airflow network model with several cracks for infiltration and 
operable windows/doors for natural ventilation.  To the greatest 
extent possible, I followed the simple house airflow network example 
file with EP-V1.3.0.

First (Severe) Error: I get the following geometry error after having 
experimented with several different view factor combinations and 
after thoroughly reviewing what seem to be logical vertices to me.

"View factors not complete. Probably bad surface descriptions in 
zone="MAIN ZONE". Enforced reciprocity has tolerance (ideal is 0.0)
=3.0292E-002. Enforced value is not within normal convergence 
tolerance (<.0001)."

Second (Fatal) Error: I get this message after EP aborts following 
the "Initializing HVAC" line in the command prompt window.  I have 
also tried several combinations of new values for the parameters it 
suggests - including increasing and decreasing them by several orders 
of magnitude.  No effect except increased processing time in some 
cases.  The audit file doesn't tell me anything.  I actually wonder 
if the first error is influencing EP's ability to converge here.

"Too many iterations (SOLVZP) in AirflowNetwork simulation
AirflowNetwork: SOLVER, Changing values for initialization flag, 
Relative airflow convergence, Absolute airflow convergence, 
Convergence acceleration limit or Maximum Iteration Number may solve 
the problem. Occurrence info: Occurrence info=STERLING VA USA TMY2-
93738 WMO#=724030, 01/01 01:00 - 02:00
AirflowNetwork: SOLVER, The previous error causes termination."

Any ideas/help appreciated - thanks!

--Kristin Field






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