[esp-r] Re: Phase change materials properties

[Jon Hand]

We are currently updating the units in the relevant files so the next version
of ESP-r will include this.  Thanks for all the good comments.

And there are many new phase change products available - if people have
suggested input values for these please send them along and (at the least
we might get suggested data into the help messages).

Regards, Jon Hand 
________________________________________
From: esp-r-bounces at lists.strath.ac.uk [esp-r-bounces at lists.strath.ac.uk] on behalf of achim.geissler at intergga.ch [achim.geissler at intergga.ch]
Sent: 29 July 2019 16:20
To: esp-r at lists.strath.ac.uk
Subject: [esp-r] Re: Phase change materials properties

Dear all,

thermal >conductivity< should have the unit W/(m K)!

Best
Achim


From: esp-r-bounces at lists.strath.ac.uk <esp-r-bounces at lists.strath.ac.uk> On Behalf Of rida at rhrk.uni-kl.de
Sent: 29 July 2019 16:18
To: 'Juanita Solano Guzmán' <juanita.solano94 at gmail.com>; esp-r at lists.strath.ac.uk
Subject: [esp-r] Re: Phase change materials properties

Hi Juanita,

There is a unit typo in the interface where thermal conductivity should be in [W/m^2K].

Using the interface you can only generate the file accounts for the linear function of latent heat of PCM. Also ESP-r can handle other function to calculate the latent heat capacity including exponential but for that you need to edit the *spf file manually and change for a different type.

For the linear case: a and b represent the coefficient for the latent heat only. y: the Latent heat x: Temperature.
If you know the characteristic at the onset and offset you can get a and b. you have two coordinate of a linear equation (0,Tm) (Maximum latent,TS).
The apparent heat capacity= Cpsolid + Latent(T)
When T is less than Tm or greater then Ts latent is zero.

Check that your *spf file is linked to the model! Open your ‘model’.cfg file and look for a line with: *spf (your special material file name)
If you couldn’t find it I think you have to add it manually and save.

Hope that help!

Regards,
Mohamad Rida


From: esp-r-bounces at lists.strath.ac.uk<mailto:esp-r-bounces at lists.strath.ac.uk> <esp-r-bounces at lists.strath.ac.uk<mailto:esp-r-bounces at lists.strath.ac.uk>> On Behalf Of Juanita Solano Guzmán
Sent: 29 July 2019 09:49
To: esp-r at lists.strath.ac.uk<mailto:esp-r at lists.strath.ac.uk>
Subject: [esp-r] Phase change materials properties

Hello to All,

I am currently trying to figure out the meaning of the input values and units when defining a phase-change material.

- Melting temperature degC: no questions
- Solidification temperature degC: no questions
- Thermal conductivity in the solid phase J/kg: In the ESPr interface the thermal conductivity is shown to have units of J/kg, I assume this is a mistake?
- Thermal conductivity in the liquid phase J/kg: same as above
- Specific heat  J/kg.K: no questions
- Latent heat of member a J/kg.K^2 and b J/kg.K: In a previous post I read that a and b, represent the values of a linear function y = ax + b. Woud this linear function correspond to the effective heat capacity given by:

C_eff = L/(Te-To) + Cp(T=To)

L - latent heat
Te - Offset temperature
To - Onset temperature
Cp - specific heat at the onset temperature

in that case, would "a" be equal to L/(Te-To) and "b" to Cp(T=To)?  And then "x" in the linear function corresponds to the temperature?

Thank you in advance for your help,

Best Regards,
Juanita