[esp-r] Re: Phase Change Material

[Achim Geissler]

Dear Thomas,

if you look in the file mscomp.db1 you will find the description for the simple model (53):

beyond phase change temperature range latent heat of material is
equal to 0. In phase change temperature range latent heat is:
1 - constant LHT=b
2 - linear function of temperature LHT=aT+b
according to this two cases can be considered:
1 - latent heat is constant in temperature range (Ts-Tm),
    y=ax+b (a=0, b=latent heat [J/kg*K])
2 - latent heat is a linear function of temperature,
    y=ax+b (a=latent heat [J/kg*K^2], b=latent heat [J/kg*K])

According to this, your approach will likely work numerically, however, if the actual behaviour / results have anything to do with reality is a totally different question.

Some suggestions:
- If you are working under contract, be sure to clearly define the extremely limited information you are basing your simulations on and the possible consequences of this to your client
- if you are working scientifically, then be sure to collect more information on the PCM

Best
Achim



On Oct 29, 2013, at 9:57 AM, Thomas Ritter <thomas.ritter at gmx.de> wrote:

> Dear all,
>  
> i'm trying to implement a PCM by the active materials section in esp-r.
>  
> Within my information about the chosen PCM, it is given only one temperature for solidfication and melting (23°C).
> Additionaly there is value given for the latent heat (13,2 kJ/kg).
>  
> In July this year a message about PCM modelling was answered with the possibility of a simpler model where latent heat flux is constant versus temperature.
>  
> Do I have to pretend that for example the melting temp. is 22,9°C and the soldifaction temp is 23,1°C and then take for latent heat member b 13,2 kJ/kg divided by 0,2 K, while a = 0? Or is there a way to calculate with temperature for melting equal temperature for solidification?
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achim.geissler at intergga.ch




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