Microinfiltration of Mg(NO3)2·6H2O into g-C3N4 and macroencapsulation with commercial sealants: A two-step method to enhance the thermal stability of inorganic composite phase change materials

Wenbo Zhang, Yixue Zhang, Ziye Ling, Xiaoming Fang and Zhengguo Zhang

Applied Energy, 2019, vol. 253, issue C, -

Abstract: Mg(NO3)2·6H2O is a promising thermal energy storage material owing to its suitable melting point and high latent heat; however, it suffers from poor thermal stability owing to dehydration. This paper presents a two-step encapsulation method to prepare a shape-stabilized Mg(NO3)2·6H2O composite phase change material (CPCM). First, Mg(NO3)2·6H2O is infiltrated into a novel porous matrix – the graphitic carbon nitride (g-C3N4). The g-C3N4 provides a microhousing for Mg(NO3)2·6H2O to prevent liquid from leaking out during the solid–liquid phase change. The g-C3N4 also significantly reduces the sub-cooling degree of Mg(NO3)2·6H2O from 29.2 °C to 1.9 °C. The Mg(NO3)2·6H2O/g-C3N4 composite with 80 wt% Mg(NO3)2·6H2O has a phase change temperature of 87.0 °C and a specific phase change enthalpy of 112.30 kJ kg−1. Second, the Mg(NO3)2·6H2O/g-C3N4 composite is shaped into a cylinder and then macroencapsulated with commercial adhesive sealants (an epoxy resin structural adhesive and silicon sealant). The sealants provide a shell for the hydrated salt to prevent dehydration. After 100 thermal cycles, the composite phase change material only lost 0.84% and 6.25% in weight with coatings of epoxy resin and silicon sealant, respectively, which are much lower than the 22.92% for the uncoated composite phase change material. The specific phase change enthalpy of the composite phase change material barely changed after 100 cycles; however, the loss for the uncoated composite phase change material reached 22.47%. The joint effect of the g-C3N4 matrix and the sealants improve the thermal stability and reliability of the Mg(NO3)2·6H2O. This sequential multi-scale encapsulation method is promising for solving the typical problems of hydrated salts.

Keywords: Phase change material; Hydrated salt; Shape-stabilized composite phase change material; Mg(NO3)2·6H2O; g-C3N4; Macroencapsulation (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0306261919312140
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:appene:v:253:y:2019:i:c:41

Ordering information: This journal article can be ordered from
http://www.elsevier.com/wps/find/journaldescription.cws_home/405891/bibliographic
http://www.elsevier. ... 405891/bibliographic

DOI: 10.1016/j.apenergy.2019.113540

Access Statistics for this article

Applied Energy is currently edited by J. Yan

More articles in Applied Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().