Cascaded latent heat thermal energy storage with molten salt/nanoparticles composite

Xin Xiao, Dongsheng Wen

Research output: Contribution to journalConference articlepeer-review

Abstract

Solar energy application with latent heat thermal energy storage (LHTES) attracts remarkable attention recently, and molten salts as phase change materials (PCMs) can be the potential media. The appropriate choosing of multiple PCMs is very significant for the performance improvement of the LHTES unit. In the present study, HITEC salt, eutectic solar salt and pure sodium nitrate with the volume ratios of 1:1:1 were used as the PCMs, and the oil was adopted as the HTF. An enthalpy-porosity model was developed to numerically investigate the heat transfer characteristics of the shell-tube LHTES unit during the charging (melting) process. Various structures infiltrated with the PCMs were studied to optimize the performance of the LHTES unit, while different mass flow rates and inlet temperatures of oil were carried out simultaneously. The results showed that different heat transfer characteristics and time-durations of the charging process can be found with the diversity of layouts of three PCMs, whereas the best solution was to adapt the temperature gradient to the phase change temperatures of the PCMs. Furthermore, aluminum oxide nanopowder (Al2O3) was doped into the salts in order to alleviate the poor thermal performance of the LHTES unit with pure PCMs, considering the scheme of series numerical studies. Temperature evolutions showed that the charging process were enhanced by the nanoparticles with high thermal conductivity.

Original languageEnglish
Pages (from-to)4455-4462
Number of pages8
JournalInternational Heat Transfer Conference
Volume2018-August
DOIs
StatePublished - 2018
Externally publishedYes
Event16th International Heat Transfer Conference, IHTC 2018 - Beijing, China
Duration: 10 Aug 201815 Aug 2018

Keywords

  • Computer Fluid Dynamics
  • Heat transfer enhancement
  • Multiple PCMs
  • Nanoparticle
  • Solar energy

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