[esp-r] Re: Phase change materials properties

Wed Jul 31 09:42:57 BST 2019

Dear Juanita,

“tsoli” is the temperature at which the PCM begins to solidify when melted and confronted with sinking temperatures. “tmelt” is the temperature at which the PCM begins to melt when solid and confronted with rising temperatures. Both temperatures also are used as endpoints of melting (tsoli) and solidification (tmelt) processes.

Best

Achim

From: esp-r-bounces at lists.strath.ac.uk <esp-r-bounces at lists.strath.ac.uk> On Behalf Of Juanita Solano Guzmán
Sent: 31 July 2019 09:32
To: Dariusz Heim <dariusz.heim at p.lodz.pl>; esp-r at lists.strath.ac.uk
Subject: [esp-r] Re: Phase change materials properties

Hello everybody,

I am looking at line 4876 (case 2) in this code

https://github.com/ <https://github.com/ESP-rCommunity/ESP-rSource/blob/master/src/ebld/spmatl.F> ESP-rCommunity/ESP-rSource/blob/master/src/ebld/spmatl.F

I still have a couple of questions. What is labeled as "tsoli" would correspond to the onset temperature? When looking at my crystallization graph I have offset = 21,25°C and onset = 23,13°C. The total latent heat is -35067 J/kg (heat out). 

In that case, in line 4880 would my shtliq correspond to 35067 J/kg (with or without the minus sign?), tsoli = 23,13°C and tmelt = 21,25°C? Is everything multiplied times 2? also, what is the meaning of the number two after the double " ** " in line 4880. 

Thank you very much. Your help is much appreciated. 

Greetings,

Juanita 

Am Mo., 29. Juli 2019 um 12:42 Uhr schrieb Dariusz Heim <dariusz.heim at p.lodz.pl <mailto:dariusz.heim at p.lodz.pl> >:

Dear Juanita,

The displayed unit for thermal conductivity should be W/(m^2K). 

The detailed explanation about "a" and "b" you can find below:

https://github.com/ESP-rCommunity/ESP-rSource/blob/master/src/ebld/spmatl.F

line 4876 (case 2).

Good luck,
Darek

W dniu 29.07.2019 o 09:48, Juanita Solano Guzmán pisze:

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 

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