[EnergyPlus_Support] COMIS questions

["Ian Doebber" <idoebber@xxxxxx>]

Two questions:

1) Have the increase in the Significant Figures for the intermediate COMIS file been applied to Energy Plus such that if I redownload it from the E+ web site I can enter in Air Mass Flow Coefficient to five decimal points.  If this fix has not been uploaded yet, is there a way I can do this fix on my own.

2) Currently, my COMIS infiltration for the Washington DC weather is dominated by Wind Effects.  I am wondering if the way I have my COMIS program set up minimizes the Stack Effects or whether COMIS in general for DC weather emphasizes wind as the main source of infiltration.  If it is due to the way I have COMIS set up, how would I change my program to have more stack infiltration such as altering my ceiling vs wall leakage areas.

Thanks
Ian

  ----- Original Message ----- 
  From: Joe Huang 
  To: EnergyPlus_Support@xxxxxxxxxxxxxxx 
  Sent: Saturday, December 13, 2003 4:30 AM
  Subject: Re: [EnergyPlus_Support] EnergyPlus/COMIS error: MATRIX SINGULAR FOR ZONE #2


  Ming,

  I have repeated your steps with the example file and found that this error
  (MATRIX SINGULAR FOR ZONE #2) was occuring due to your third change where
  you reduced the Air Mass Flow Coefficient from 0.001 to 0.0001.  The problem
  is caused by the intermediate COMIS input file (eplusout.cif) not being
  written to the sufficient level of precision, so that the input 0.0001
  appeared as 0.000, i.e., interpeted as a flow coefficient of 0.  I solved
  the problem by increasing the precision for writing the flow coefficient and
  exponents from three decimal points (F10.3) to five decimal points (F10.5).
  I will upload that fix to the EnergyPlus server on Monday.  Until the
  correction makes it into the compiled code on the server, please keep the
  flow coefficients and exponent at above 0.001.  Even after the fix is
  implemented, you need to keep them at above 0.00001.

  Joe
  ----- Original Message -----
  From: "waspoorboy" <mingsbox@xxxxxxxxxxxxxx>
  To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
  Sent: Tuesday, December 09, 2003 11:20 AM
  Subject: [EnergyPlus_Support] EnergyPlus/COMIS error: MATRIX SINGULAR FOR
  ZONE #2


  > To reproduce this problem,
  > I took example file 3zvent.idf
  > #1: Delete all cracks. [only two window and one door left]
  > #2: Remove East_Zone from COMIS ZONE DATA
  > #3: Change the Air Mass Flow Coeff from 0.001 to 0.0001
  > #4: Execute EnergyPlus and Fatal error will be there.
  >
  > COMIS AIR FLOW:OPENING,
  > WiOpen1,  !- Name
  > 0.001,  !- Air Mass Flow Coefficient When Window or Door Is Closed
  > 0.667,  !- Air Mass Flow Exponent When Window or Door Is Closed
  >
  > Is this problem solvable ?
  > Thanks,
  > Ming
  >
  >
  >
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