IIR document

Characterization of the urea-sodium nitrate eutectic mixture as a PCM: phase segregation.

Number: 2014

Author(s) : QUANT L., DIARCE G., BOUZAS L., GARCÍA-ROMERO E.

Summary

The eutectic mixture formed by urea and sodium nitrate has been previously identified by the authors as a PCM candidate for heating and domestic hot water applications. It presents a melting point of 85 °C, a melting enthalpy of 172 J/g, and a price of around 0.9 €/kg. Eutectic mixtures are claimed as congruent melting materials in PCM literature. However, the studied mixture showed phase segregation when exposed to repeated melting-solidification cycles. Thus, the mixture was studied in order to assess the mechanisms that cause the phenomenon. Experiments consisting of thermal cycling of samples using different cooling rates were carried out. Subsequently, the segregated materials were analyzed by different techniques, including XRD, DSC, PLM, and SEM. The results established a relationship between the operating conditions with the resulting crystal structures, which explain the phase segregation in the eutectic mixture. Besides, a mitigation measure was determined.

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Pages: 8

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Details

  • Original title: Characterization of the urea-sodium nitrate eutectic mixture as a PCM: phase segregation.
  • Record ID : 30028862
  • Languages: English
  • Subject: Technology
  • Source: 13rd IIR Conference on Phase-Change Materials and Slurries for Refrigeration and Air Conditioning. Proceedings: (online) Vicenza, Italy, September 1-3, 2021.
  • Publication date: 2021/09/01
  • DOI: http://dx.doi.org/10.18462/iir.PCM.2021.2014

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