Role of surface effects in the determination of phase change temperature of PCMs

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21110%2F21%3A00354687" target="_blank" >RIV/68407700:21110/21:00354687 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1063/5.0069595" target="_blank" >https://doi.org/10.1063/5.0069595</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/5.0069595" target="_blank" >10.1063/5.0069595</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Role of surface effects in the determination of phase change temperature of PCMs

Popis výsledku v původním jazyce

We had introduced a microscopic technique to obtain heat capacity peaks near first-order phase transitions in polycrystalline phase change materials (PCMs). Such PCMs are composed of a large number of segments or grains, so that the total heat capacity of a PCM is a double average of heat capacities in the individual grains. One average is over surface (or boundary) effects occurring due to interactions of grains with their surroundings, while the other average is over grain sizes. Using this approach, we were able to derive a formula for heat capacity peaks and use it to very accurately fit experimental data for three selected PCMs measured by adiabatic scanning calorimetry. The fitted values of the phase change temperature for these three PCMs were not convincing, however. In this paper we argue that the reason for this controversy stems from too a crude approximation of surface effects that was used originally. Therefore, here we propose an improvement of our technique by suggesting a more appropriate approximation that still leads to as accurate fits as the original one. We illustrate this for one of the three PCMs.

Název v anglickém jazyce

Role of surface effects in the determination of phase change temperature of PCMs

Popis výsledku anglicky

We had introduced a microscopic technique to obtain heat capacity peaks near first-order phase transitions in polycrystalline phase change materials (PCMs). Such PCMs are composed of a large number of segments or grains, so that the total heat capacity of a PCM is a double average of heat capacities in the individual grains. One average is over surface (or boundary) effects occurring due to interactions of grains with their surroundings, while the other average is over grain sizes. Using this approach, we were able to derive a formula for heat capacity peaks and use it to very accurately fit experimental data for three selected PCMs measured by adiabatic scanning calorimetry. The fitted values of the phase change temperature for these three PCMs were not convincing, however. In this paper we argue that the reason for this controversy stems from too a crude approximation of surface effects that was used originally. Therefore, here we propose an improvement of our technique by suggesting a more appropriate approximation that still leads to as accurate fits as the original one. We illustrate this for one of the three PCMs.

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2021

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

AIP Conference Proceedings 2429

ISBN

978-0-7354-4139-2

ISSN

0094-243X

e-ISSN

1551-7616

Počet stran výsledku

4

Strana od-do

—

Název nakladatele

AIP Conference Proceedings

Místo vydání

New York

Místo konání akce

Kazimierz Dolny

Datum konání akce

1. 9. 2021

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

—