[Bldg-sim] TRANSFER FUNCTION FOR HEAVY AND THICK WALLS

Danielle E.M. Bond dmiller208 at gmail.com
Fri May 16 06:53:47 PDT 2014


Can you use Energy Plus? It has a conduction finite difference option that
might avoid the computational problem that the CTF method has.

Regards,
Danielle Bond

On Fri, May 16, 2014 at 9:37 AM, Luis Miguel Blanes Restoy <
lmblanes at gmail.com> wrote:

> Luis
>
> You may explore E+ different ways of dealing with CTF (state space method
> mainly). CTF calculations become unstable for short time steps and massive
> constructions (it is at the end a computational problem). E-Quest may
> decide on your arrangement to be unstable before running the simulation
> (not sure of this). There are solutions to solve this problem (Seem 1987),
> and I guess these have been incorporated into CTF calculation within E+. It
> is a matter of giving E+ a go and try out if your example may work there.
>
> E+ also handles Finite Differences Methods for CTF calculations, but I am
> not versed in this field.
>
> You can find more information in the E+ Engineering Reference Manual.
>
> Regards
> Abrazos desde Hibernia
> Luis
>
>
>
>
> 2014-05-16 14:06 GMT+01:00 Luis Peréz-Lombard <lpl at us.es>:
>
>>  Dear colleagues,
>>
>>
>>
>> As you probably know, Conduction Transfer Function (CTF) method does not
>> handle thick and massive walls, because the accuracy of the CTF
>> coefficients is degraded. In particular, in DOE-2, you get the following
>> message:
>>
>>
>>
>> *“Cannot simulate LAYERS …….. as given. The wall is too thick or too
>> dense”*
>>
>>
>>
>> I have heard of a possible solution to solve this problem by dividing the
>> wall into thin layers. I have made an attempt in e-quest, but the problem
>> remains, and I do not know how to proceed.
>>
>>
>>
>> Any insight on this issue would be appreciated.
>>
>> Sincerely,
>>
>> LPL
>> -------------------------------------------------------------
>> Luis Pérez-Lombard
>> Dr. Ingeniero Industrial
>> Profesor Contratado Doctor
>> Departamento de Ingeniería Energética
>> Escuela Superior de Ingenieros
>> Universidad de Sevilla
>> Camino de los Descubrimientos s/n
>> 41092 SEVILLA
>> Tfno.:      95.448.72.56
>> Fax:         95.446.31.53
>> e-mail:    lpl at us.es
>> -------------------------------------------------------------
>>
>> _______________________________________________
>> Bldg-sim mailing list
>> http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org
>> To unsubscribe from this mailing list send  a blank message to
>> BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG
>>
>>
>
>
> --
> LUIS M BLANES RESTOY
>
> *IRUSE *INFORMATICS RESEARCH UNIT FOR SUSTAINABLE ENGINEERING
> www.iruse.ie
>  mobile Ireland: +353 83 1346875
> mobile Spain: +34 609097818
> skype: lmblanes
> email: lmblanes at gmail.com
>
>
>
>
> _______________________________________________
> Bldg-sim mailing list
> http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org
> To unsubscribe from this mailing list send  a blank message to
> BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20140516/ad6fb162/attachment.htm>


More information about the Bldg-sim mailing list