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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Hello,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>I have a problem modelling pollutant flow. I have a
simple one zone-building with inhabitants producing CO2. I use this
concentration to control a fan. The problem is that when I run the simulation,
I get the following warning:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'>***** WARNING
***** UNIT 37 TYPE 56, TIME = 4.188E+00<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'> COMIS MESSAGE
***** WARNING ***** <o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'> Pollutant
transport solver : Small timestep<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'> needed (Tau <
10 sec), but is limited to 1 sec<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'>appearing at
every time step. But, when I decrease the time step below 56.25 sec (0.5^6*1hr),
I get a range check error during the simulation (the first couple of hours are
plotted before the error). Does anyone have experience with this? What causes
the error? And is such a small time step always needed when simulating
pollutants or does it depend on e.g. the zone volume? <o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'>Thanks a lot,<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'>Stefan de Kool<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span lang=EN-GB
style='font-size:12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Cauberg-Huygen Raadgevende Ingenieurs</span></font><span
lang=EN-GB><o:p></o:p></span></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Lokatie Rotterdam</span></font><span lang=EN-GB><o:p></o:p></span></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span lang=EN-GB
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
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