Experimental investigations on phase separation for different heights of sodium acetate water mixtures under different conditions

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Abstract

Phase separation is a key problem when using sodium acetate trihydrate (SAT) as phase change heat storage material. The formation of phase separation is highly correlated to the composition of SAT based heat storage material, the material height, operation method and environmental condition. This study focus on the phase separation investigation by means of measuring exact water proportions in different layers of SAT samples. The SAT samples were made with or without different amount of excess water or thickening agents at different heights. Then the samples were tested in supercooled state under different environmental conditions such as short or long term supercooling periods, standing still or shaking from time to time during supercooling, repeated heating and activating and low ambient temperature. The solidification of supercooled samples was activated from top or bottom in order to verify the influence of activation methods. The water proportions in different layers of SAT samples were measured and summarized for comparison. It can be concluded from the experiments that suitable amount of excess water or thickening agents and proper shaking are beneficial to reduce or avoid phase separation. On the other hand, SAT without any additives, repeated heating and activating and low ambient temperature are favourable to forming phase separation for supercooled SAT materials.
Original languageEnglish
JournalApplied Thermal Engineering
Volume148
Pages (from-to)796-805
ISSN1359-4311
DOIs
Publication statusPublished - 2019

Keywords

  • Sodium acetate trihydrate
  • Phase separation
  • Water proportion
  • Phase change material
  • Heat storage

Cite this

@article{7dcf13ad5c1048bd837f4089d9e6bc68,
title = "Experimental investigations on phase separation for different heights of sodium acetate water mixtures under different conditions",
abstract = "Phase separation is a key problem when using sodium acetate trihydrate (SAT) as phase change heat storage material. The formation of phase separation is highly correlated to the composition of SAT based heat storage material, the material height, operation method and environmental condition. This study focus on the phase separation investigation by means of measuring exact water proportions in different layers of SAT samples. The SAT samples were made with or without different amount of excess water or thickening agents at different heights. Then the samples were tested in supercooled state under different environmental conditions such as short or long term supercooling periods, standing still or shaking from time to time during supercooling, repeated heating and activating and low ambient temperature. The solidification of supercooled samples was activated from top or bottom in order to verify the influence of activation methods. The water proportions in different layers of SAT samples were measured and summarized for comparison. It can be concluded from the experiments that suitable amount of excess water or thickening agents and proper shaking are beneficial to reduce or avoid phase separation. On the other hand, SAT without any additives, repeated heating and activating and low ambient temperature are favourable to forming phase separation for supercooled SAT materials.",
keywords = "Sodium acetate trihydrate, Phase separation, Water proportion, Phase change material, Heat storage",
author = "Weiqiang Kong and Mark Dannemand and Berg, {Jakob Brink{\o}} and Jianhua Fan and Gerald Englmair and Janne Dragsted and Simon Furbo",
year = "2019",
doi = "10.1016/j.applthermaleng.2018.10.017",
language = "English",
volume = "148",
pages = "796--805",
journal = "Applied Thermal Engineering",
issn = "1359-4311",
publisher = "Pergamon Press",

}

TY - JOUR

T1 - Experimental investigations on phase separation for different heights of sodium acetate water mixtures under different conditions

AU - Kong, Weiqiang

AU - Dannemand, Mark

AU - Berg, Jakob Brinkø

AU - Fan, Jianhua

AU - Englmair, Gerald

AU - Dragsted, Janne

AU - Furbo, Simon

PY - 2019

Y1 - 2019

N2 - Phase separation is a key problem when using sodium acetate trihydrate (SAT) as phase change heat storage material. The formation of phase separation is highly correlated to the composition of SAT based heat storage material, the material height, operation method and environmental condition. This study focus on the phase separation investigation by means of measuring exact water proportions in different layers of SAT samples. The SAT samples were made with or without different amount of excess water or thickening agents at different heights. Then the samples were tested in supercooled state under different environmental conditions such as short or long term supercooling periods, standing still or shaking from time to time during supercooling, repeated heating and activating and low ambient temperature. The solidification of supercooled samples was activated from top or bottom in order to verify the influence of activation methods. The water proportions in different layers of SAT samples were measured and summarized for comparison. It can be concluded from the experiments that suitable amount of excess water or thickening agents and proper shaking are beneficial to reduce or avoid phase separation. On the other hand, SAT without any additives, repeated heating and activating and low ambient temperature are favourable to forming phase separation for supercooled SAT materials.

AB - Phase separation is a key problem when using sodium acetate trihydrate (SAT) as phase change heat storage material. The formation of phase separation is highly correlated to the composition of SAT based heat storage material, the material height, operation method and environmental condition. This study focus on the phase separation investigation by means of measuring exact water proportions in different layers of SAT samples. The SAT samples were made with or without different amount of excess water or thickening agents at different heights. Then the samples were tested in supercooled state under different environmental conditions such as short or long term supercooling periods, standing still or shaking from time to time during supercooling, repeated heating and activating and low ambient temperature. The solidification of supercooled samples was activated from top or bottom in order to verify the influence of activation methods. The water proportions in different layers of SAT samples were measured and summarized for comparison. It can be concluded from the experiments that suitable amount of excess water or thickening agents and proper shaking are beneficial to reduce or avoid phase separation. On the other hand, SAT without any additives, repeated heating and activating and low ambient temperature are favourable to forming phase separation for supercooled SAT materials.

KW - Sodium acetate trihydrate

KW - Phase separation

KW - Water proportion

KW - Phase change material

KW - Heat storage

U2 - 10.1016/j.applthermaleng.2018.10.017

DO - 10.1016/j.applthermaleng.2018.10.017

M3 - Journal article

VL - 148

SP - 796

EP - 805

JO - Applied Thermal Engineering

JF - Applied Thermal Engineering

SN - 1359-4311

ER -