Re: [EnergyPlus_Support] moisture simulation with MTF or EMPD

[Lixing Gu <gu@xxxxxxxxxxxx>]

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
>  >
>  >
>  >
>  >
>  >
>  >
>  >
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>  ========================================================
>  Michael J. Witte, GARD Analytics, Inc.
>  EnergyPlus Testing and Support
>  EnergyPlus-Support@xxxxxxxx
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