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AW: AW: [EnergyPlus_Support] moisture simulation with MTF or EMPD



Mike
Thanks a lot for your help. We will try to measure the needed coefficients
in a test room. I will let you know the results.
Hans, Lenum AG

  -----Ursprüngliche Nachricht-----
  Von: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]Im Auftrag von Michael J. Witte
  Gesendet: Wednesday, July 19, 2006 6:28 PM
  An: EnergyPlus_Support@xxxxxxxxxxxxxxx
  Betreff: Re: AW: [EnergyPlus_Support] moisture simulation with MTF or EMPD


  Some further thoughts on the subject from another moisture expert. I asked
him
  if he thought the EMPD or MTF model would be suitable for your purpose:

  "I guess the question is what they are trying to simulate or predict using
  simulation. If they are trying to determine the performance of the clay o
  calciumsilicat panels themselves to see if it will work as they propose,
then I
  would say no. If they know the performance of the clay o calciumsilicat
panels
  and they are trying to approximate that result for the rest of the
building
  impact then they might be able to do that. If they are trying to determine
the
  impact on the rest of the building then they can monitor the performance
of the
  panel to see if it is within its range. But if they are trying to predict
the
  panel performance itself to see if it will provide the moisture shift from
  summer to winter, than that would be outside of the scope of the current
  moisture models."

  Mike

  On 13 Jul 2006 at 17:27, Hans Hatt wrote:

  > Dear Lixing Gu
  >
  > thanks for your response. How can I find the right dimensionless
  > coefficients a, b, c and d for light clay in the EMPD model? The
isothermal
  > moisture capacity is about 2.2 m3/kg. Is there some literature about the
  > EMPD model?
  >
  > If the EMPD model doesn't work because of its limitations to small
  > penetration depth, do you think the MTF model could work better.
  >
  > Thanks a lot for your help.
  >
  > Hans
  >
  > -----Ursprüngliche Nachricht-----
  > Von: EnergyPlus_Support@xxxxxxxxxxxxxxx
  > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]Im Auftrag von Lixing Gu
  > Gesendet: Thursday, July 13, 2006 3:13 PM
  > An: EnergyPlus_Support@xxxxxxxxxxxxxxx
  > Betreff: Re: [EnergyPlus_Support] moisture simulation with MTF or EMPD
  >
  >
  > Hans:
  >
  > The EMPD model assumes a sum of moisture adsorption and desorption at an
  > interior surface during a short period is near zero. Although increasing
  > the
  > penetration depth may not be a reasonable approach (possible beyond the
  > model capability), I would suggest to try it and see whether you get
  > reasonable results or not. If you have measured data, you may know the
  > model
  > limitation.
  >
  > Please let me know if you need more information on the model.
  >
  > Thanks.
  >
  > Lixing Gu
  >
  > ----- Original Message -----
  > From: "Hans Hatt" <hatt@xxxxxxxxx>
  > To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
  > Sent: Wednesday, July 12, 2006 2:14 AM
  > Subject: AW: [EnergyPlus_Support] moisture simulation with MTF or EMPD
  >
  > > Thanks a lot for your reply.
  > >
  > > Do you think we can use the MTF model, if the relative moisture in the
  > > materials will remain between 30% and 70%. For the MTF model we have
  > > already
  > > an idea about the needed coefficients.
  > >
  > > The penetration depth in the EMPD model is just about 10 to 15 mm. For
  > the
  > > anual storage of moisture I think we need more than 100 mm of storage
  > > material. The Engineering Reference says, that the EMPD equation just
  > > holds
  > > for a short period of time. We would like to study the moisture
storage
  > > over
  > > a whole year. Can we use in this case the EMPD model?
  > >
  > > Best wishes
  > >
  > > Hans, Lenum AG
  > >
  > >
  > >
  > > -----Ursprungliche Nachricht-----
  > > Von: EnergyPlus_Support@xxxxxxxxxxxxxxx
  > > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]Im Auftrag von Michael J.
  > Witte
  > > Gesendet: Montag, 10. Juli 2006 21:10
  > > An: EnergyPlus_Support@xxxxxxxxxxxxxxx
  > > Betreff: Re: [EnergyPlus_Support] moisture simulation with MTF or EMPD
  > >
  > >
  > > The MTF model would probably not be appropriate for this task. Note
the
  > > cautions about using it over a wide range of conditions in the Input
  > > Output
  > > Reference (p. 73, pdf p. 110) and the Engineering Reference (p. 24,
pdf
  > > p.
  > > 56).
  > >
  > > The best option within EnergyPlus would be the EMPD model, however,
you
  > > may not
  > > be able to find the appropriate coefficient data for this model for
the
  > > specialized material you are studying.
  > >
  > > Mike
  > >
  > > On 7 Jul 2006 at 6:14, hatt_hans wrote:
  > >
  > > > We would like to do an ep simulation for a magazine which stores
  > > > important documents. To balance the relative humidity in the
magazine
  > > > we would like to use clay o calciumsilicat panels at the inside
  > > > surfaces. With these materials we would like to store the moisture
  > from
  > > > the summer to the winter period. Should we use the MTF or EMPD model
  > > > for simulation? How can we get the needed parameters for clay and
  > > > calciumsilicat. In the moisture.idf file we have found already some
  > > > materials, which were very helpful.
  > > >
  > > > Thanks a lot for help.
  > > >
  > > > Hans, Lenum AG
  > > >
  > > >
  > > >
  > > >
  > > >
  > > >
  > > >
  > > > The primary EnergyPlus web site is found at:
  > > > http://www.energyplus.gov
  > > >
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  > > > http://groups.yahoo.com/group/EnergyPlus_Support/
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  > > >
  > > >
  > >
  > > ========================================================
  > > Michael J. Witte, GARD Analytics, Inc.
  > > EnergyPlus Testing and Support
  > > EnergyPlus-Support@xxxxxxxx
  > >
  > >
  > >
  > >
  > >
  > >
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