[TRNSYS-users] Type204-PCM

[David Bradley]

Bezeid,
  Because there is not a model for a PCM material built in to the Type56 
building model, there needs to be some way for a Type that models the 
PCM to interface with the rest of the building (for example so that the 
inside surface of the PCM material can be part of the radiative and 
convective energy balance of the thermal zone). The way that this 
interaction is often achieved is to define a BOUNDARY wall in 
TRNBuild/Type56. A BOUNDARY wall is a surface that interacts with the 
zone on one side and has some known temperature on the other side. When 
the BOUNDARY wall interfaces with an external Type (such as 204), the 
temperature required by the BOUNDARY wall is the interface temperature 
between the back of the BOUNDARY wall and the front of the PCM material. 
Typically the way that the coupling is achieved is that Type56 
calculates the inside surface temperature (TSI) and the amount of energy 
being transfered through the BOUNDARY wall into the PCM (QCOMI and/or 
QCOMO). These values are passed to Type204 as inputs; Type204 then 
computes the reaction of the PCM to those inputs and calculates a new 
interface temperature, which is passed back to Type56 as the BOUNDARY 
wall's outside temperature. Iteration continues until energy balances.
Kind regards,
 David



bezeid.deddy at orange-ftgroup.com wrote:
>
>
> Hello TRNSYS Users,
> I am Deddy bezeid and I make a thesis at the bretagne-sud university, 
> I am a new user of TRNSYS and I encounter problems on the TYPE204 - 
> PCM and I already found somebody who put the same questions with which 
> I would like to have answers, here the questionnaires and thank you 
> for your assistance
>
>  I want to use TRNSYS Type 204 for the simulation of PCM layers on a 
> building. Has anyone used this type before? It takes forever to run an 
> one week simulation...However the main problem is i cannot understand 
> the way the model simulates a PCM layer... My questions are about the 
> SUNSPACE example supplied into the files package loaded : There are 2 
> air zones in the TRNBUILD type 56 model of this example : SunZone and 
> BackZone. SunZone is where "PCM wall" has been installed. So :
>
> - How to make the difference if we want "PCM layer" into all walls 
> surfaces from SunZone, or only into some of them?
>  - Why the resistance of the "PCM massless layer" created in TRNBUILD 
> is only 0.1 m².K.h/kJ?
>  - Why the "PCM wall" using the "PCM massless layer" into SunZone 
> (boundary wall calling T_PCM input) presents a so small surface of 0.2 
> m²?
>
> - Why QCOMI is taken from the same "PCM Wall" (14) and not from other 
> walls?
>  - Do we have to change values into the 4 text external files supplied 
> (NodeTemp.txt, Tila.txt, Ceff1.txt, ALKU.txt) or do we only have to 
> call their path?
>
>  - Why the PCMeT (average surface temperature of "PCM wall")calculated 
> by type 204 is sent to the boundary "PCM wall" input (T_PCM) into type 
> 56 ?
>
>  type 204 receives QCOMI from 0.2 m² surface (14), and T_AIR from 
> SunZone volume,
> then it calculates and sends T_PCM to boundary input for 0.2 m² 
> surface (14)
>  => I don't see in which way this sequence allows modelization of PCM 
> introduction into a wall?
> I searched all the mailing list but i just found the same 
> questions..and no answers... Please help...Thanks in advance
> Deddy bezeid
>
>
> ------------------------------------------------------------------------
>
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-- 
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Thermal Energy System Specialists (TESS), LLC 
David BRADLEY                      22 N. Carroll Street - Suite 370 
Partner                            Madison, WI 53703 
                                   USA
P: +1.608.274.2577 
F: +1.608.278.1475
E-mail: bradley at tess-inc.com 
Web Pages:  http://www.tess-inc.com    and      http://www.trnsys.com

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