[esp-r] Re: phase change materials

[Achim Geissler]

Hi Arianna,

so probably you are using type 53 (you can see that in the .spm file, by the way, "Type").

The PCM should go in the middle node of the innermost layer (or the "plasterboard" layer, in any case). I have no idea what the default parameters in the database are. Did you change the latent heat to meet the actual material you are using? Again, I always found it very informative to have a surface with and without PCM side by side and look at the surface and / or central node temperatures of the layer in question. Did you do that? From these temperatures you can also estimate if you are actually melting / solidifying the PCM as Monika mentioned.

Are you using h3k output? If not, it may be an additional idea. You should find a variable "PCMFAC" in the dictionary. This, I think, is a factor which is 0 for solid and 1 for liquid (or the other way around) and thus gives direct information on what is happening with the PCM.

Best
Achim


On Sep 11, 2014, at 7:53 PM, Arianna Sdei <A.Sdei at brighton.ac.uk> wrote:

> Hi Achim,
> I am using phase change plasterboard via the active material database and I am using quite a bit of it. I am using it on all internal walls of two rooms in a house. It makes only a tiny difference to the temperature and I think I am not using it in the right way at the moment. I should be able to see a reduction of 1 or 2k but I am not. What can I look at? can the way I am positioning the material make any difference? I am trying to have the pcm exposed. Let me know,
> Thank  you.
> Arianna    
>  
> From: esp-r-bounces at lists.strath.ac.uk [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Achim Geissler
> Sent: 10 September 2014 18:16
> To: esp-r at lists.strath.ac.uk Club
> Subject: [esp-r] Re: phase change materials
>  
> Hi Arianna,
>  
> you write you can't see "substantial reduction" - but you do see a reduction? You will need quite a bit of PCM for substantial differences (.gt. 1 to 2 K), probably.
>  
> Which PCM model are you using? I think the basic "53" model cannot really take different temperatures for melting/solidification into account.
>  
> A simple approach for testing: If you have two otherwise identical surfaces, put the PCM in one and then look at the temperature profiles for a day for these surfaces (or split one of the PCM surfaces into two and remove the PCM from one of these). This should quickly give you an idea on if something is happening ("something" may be disappointingly small temperature differences).
>  
> Best
> Achim
>  
>  
>  
> Von: esp-r-bounces at lists.strath.ac.uk [mailto:esp-r-bounces at lists.strath.ac.uk] Im Auftrag von Arianna Sdei
> Gesendet: Mittwoch, 10. September 2014 16:59
> An: esp-r at lists.strath.ac.uk Club
> Betreff: [esp-r] phase change materials
>  
> Dear All,
>  
> I am trying to use phase change materials, phase change plasterboard, via the active components. I am using a melting temperature of 26°C and a solidification temperature of 27°C. I am not sure about the solidification temperature and I would like to know if some of you can advise on this. I am trying to have the PCM exposed, so I always position it on the internal layer as I suppose when the software asks for the position it starts counting the existing layers from the exterior.
>  
> However I try, I can’t see any substantial reduction in the indoor temperature during a hot summer month. Can any of you give some advice on how to reduce the indoor temperature further by changing the parameters?
>  
> Thank you in advance,
>  
> Best regards,
>  
> Arianna   
>  
> Arianna Sdei
>  
> Research Fellow IFORE (Innovation For Renewal)
>  
> UNIVERSITY OF BRIGHTON
>  
> Moulsecoomb, Lewes Road, Brighton, BN2 4AT
>  
> mobile: 0044 (0)7981739024
>  
>  
> 
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