[esp-r] Re: MZELWE Longwave Flux Messages

[Holger Bertling]

THANK YOU BOTH!

For the protocol:

There was only mineral wool on the outside-face.
I plastered it with light plaster
and there were 30 Percent less mistakes.
I plastered it with dense plaster
and there were 60 Percent less mistakes.
I increased the time-steps per hour to 30
and there are no mistakes anymore.

Best regards,
happy Holger


Am Donnerstag, den 16.10.2008, 13:26 +0200 schrieb Holger Bertling:
> Hi All,
> 
> do you mean the "Zone side: time-steps/hour"?
> First it was 12 steps
> and I increased ist up to 60 steps
> and the Messages increased, too.
> So it seems to be the material.
> 
> Is "Zone side: time-steps/hour" the right switch?
> What is in your opinion a good time-step-value?
> 
> Best regards,
> Holger
> 
> 
> 
> Am Mittwoch, den 15.10.2008, 09:35 -0400 schrieb Ferguson, Alex:
> > >This was caused by the choice of high exterior surface
> > >absorptivity and emissivity values, low specific heat, 
> > >and low thermal conductivity.
> > 
> > The low specific heat and conductivity, and the high absorptivity and
> > emissivity values translate into a small thermal time constant for the
> > state equation describing the temperature of the surface. The simulation
> > becomes unstable when the solution time step approaches (or exceeds)
> > this time step; increasing the time resolution may also produce more
> > stable simulations. 
> > 
> > - Alex 
> > 
> > -----Original Message-----
> > From: esp-r-bounces at lists.strath.ac.uk
> > [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Lukas Swan (Dal)
> > Sent: Wednesday, October 15, 2008 8:02 AM
> > To: 'Holger Bertling'
> > Cc: esp-r at lists.strath.ac.uk
> > Subject: [esp-r] Re: MZELWE Longwave Flux Messages
> > 
> > Hi Holger,
> > I have seen this in simulations before as well. It means that the long
> > wave flux from the exterior building surfaces is greater than a typical
> > expected range. I added a bit of verbosity to the source code once and
> > found that it was always caused by my exterior surface temperature being
> > too high. This was caused by the choice of high exterior surface
> > absorptivity and emissivity values, low specific heat, and low thermal
> > conductivity.
> > 
> > Take a good look at the materials you are using and how they are
> > situated into the construction. Adjust some of these values and the
> > issue will likely decrease.
> > 
> > Lukas Swan
> > Dalhousie Univ.
> > Canada
> > 
> > -----Original Message-----
> > From: esp-r-bounces at lists.strath.ac.uk
> > [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Holger Bertling
> > Sent: October-14-08 1:34 PM
> > To: esp-r at lists.strath.ac.uk
> > Subject: [esp-r] MZELWE Longwave Flux Messages
> > 
> > Dear All,
> > 
> > during my simulations I get a lot of these messages:
> > 
> > Wall-6:Raum_3 @ increment 31883
> >  This is considered high and a correlation will be used.
> >  <sky =  -222.7 <buildings = -145.3 <ground = -197.0
> >  MZELWE: a longwave flux of   -578.9 Watts has been calculated for
> > Wall-6:Raum_1 @ increment 31884
> >  This is considered high and a correlation will be used.
> >  <sky =  -228.3 <buildings = -147.9 <ground = -202.8
> >  MZELWE: a longwave flux of   -496.6 Watts has been calculated for
> > Wall-6:Raum_3 @ increment 31884
> >  This is considered high and a correlation will be used.
> >  <sky =  -197.3 <buildings = -126.0 <ground = -173.3
> >   50 %   complete; expected finish time : Tue Oct 14 18:14:36 2008
> >  MZELWE: a longwave flux of   -538.3 Watts has been calculated for
> > Wall-6:Raum_1 @ increment 79966
> >  This is considered high and a correlation will be used.
> >  <sky =  -213.7 <buildings = -136.3 <ground = -188.3
> >  MZELWE: a longwave flux of   -655.9 Watts has been calculated for
> > 
> > Does anybody know,
> > what that means
> > and if its bad or OK?
> > 
> > Thanks in advance,
> > Holger
> > 
> > 
> > _______________________________________________
> > esp-r mailing list
> > esp-r at lists.strath.ac.uk
> > http://lists.strath.ac.uk/mailman/listinfo/esp-r
> > 
> > 
> > _______________________________________________
> > esp-r mailing list
> > esp-r at lists.strath.ac.uk
> > http://lists.strath.ac.uk/mailman/listinfo/esp-r
> > 
> > _______________________________________________
> > esp-r mailing list
> > esp-r at lists.strath.ac.uk
> > http://lists.strath.ac.uk/mailman/listinfo/esp-r
> 
> 
> _______________________________________________
> esp-r mailing list
> esp-r at lists.strath.ac.uk
> http://lists.strath.ac.uk/mailman/listinfo/esp-r