Novel microstructured polyol-polystyrene composites for seasonal heat storage

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2016-06-15
Major/Subject
Mcode
Degree programme
Language
en
Pages
11
96-106
Series
Applied Energy, Volume 172
Abstract
We propose a robust route to prepare novel supercooling microstructured phase change materials (PCMs) suitable for seasonal thermal energy storage (STES) or heat protection applications. Two supercooling polyols, erythritol and xylitol, are successfully prepared as novel microencapsulated PCM-polystyrene composites with polyol mass fractions of 62 wt% and 67 wt%, respectively, and average void diameter of ~50 μm. Thermal properties of the composites and bulk polyols are studied thoroughly with differential scanning calorimetry (DSC) and thermal conductivity analyzer. Significant differences in heat storage properties of microstructured and bulk PCM are observed. The heat release of microstructured erythritol is more controlled than that of bulk PCM, making the novel microengineered PCMs particularly interesting for STES. In the case of bulk PCM, the heat release may occur spontaneously due to crystallization by surface roughnesses or impurities, whereas these factors have only little impact on the crystallization of microstructured erythritol, making the novel composite more reliable for long-term heat storage purposes. In addition, microstructured polyol-polystyrene composites show anomalous enhancement in the specific heat as compared to bulk polyols. This enhancement may originate from strong polyol-surfactant interactions in the composites.
Description
Keywords
Crystallization, High internal phase emulsion, Polyol, Seasonal thermal energy storage, Supercooling
Other note
Citation
Puupponen , S , Mikkola , V , Ala-Nissilä , T & Seppälä , A 2016 , ' Novel microstructured polyol-polystyrene composites for seasonal heat storage ' , Applied Energy , vol. 172 , pp. 96-106 . https://doi.org/10.1016/j.apenergy.2016.03.023