Using organic phase-change materials for enhanced energy storage inwater heaters: An experimental study

Jifen Wang, Huaqing Xie, Zhixiong Guo, Le Cai, Kai Zhang

Research output: Contribution to journalArticle

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Organic phase-change material for enhanced energy storage was prepared by adding SiO2 particles in a certain proportion into molten palmitic acid (PA) with stirring and intensive sonication at a constant temperature. The thermal properties of the SiO2/PA composite were experimentally characterized. As compared with pure PA, the latent heat capacity of the composite with the addition of 3 wt.% SiO2 particles increased by 51.7 kJ/kg, reaching 214.7 kJ/kg, which is the highest value among the composites tested with varying SiO2 ratio from 1 to 5 wt.%. The thermal conductivity of the 3 wt.% SiO2/PA composite also increased by 12% at 30°C (solid state) and 7% at 70°C (liquid state), respectively. A water heater was built and tested with embedded capsules containing the 3 wt.% SiO2/PA composite and pure PA, respectively. The lab-built phase-change water heater was much smaller in size than an ordinary household water heater in comparison and uses reduced electrical power. However, water heater responded faster and had a larger volume ratio of hot water output to water heater size. During the turning-off test, the water heater with 3 wt.% SiO2/PA provided 2.23 times hot water volume of heater size, while the ordinary water heater provided 1.41 times hot water volume of tank size.

Original languageEnglish (US)
Pages (from-to)167-178
Number of pages12
JournalJournal of Enhanced Heat Transfer
Issue number2
Publication statusPublished - Jan 1 2019


All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


  • Composite
  • Energy storage enhancement
  • Latent heat
  • Organic phase-change material
  • Water heater

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