Solar Energy Storage in Phase Change Materials: First-Principles Thermodynamic Modeling of Magnesium Chloride Hydrates

详细信息    查看全文

• 作者：Philippe F. Weck ; Eunja Kim
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：March 6, 2014
• 年：2014
• 卷：118
• 期：9
• 页码：4618-4625
• 全文大小：443K
• 年卷期：v.118,no.9(March 6, 2014)
• ISSN：1932-7455

文摘

Thermal energy storage in salt hydrate phase change materials, such as magnesium chloride hydrates, represents an attractive option for solar energy applications. In this study, the structural, electronic, and thermodynamic properties of magnesium dichloride hexahydrate, MgCl₂路6H₂O, and its dehydrated phases, MgCl₂路nH₂O (n = 4, 2, 1), were computed within the framework of density functional theory. Densities of states were predicted, and phonon analysis using density functional perturbation theory was performed at equilibrium volume to derive isochoric thermal properties (i.e., Helmholtz free energy, entropy, and isochoric heat capacity). Isobaric thermal properties (i.e., Gibbs free energy, isobaric heat capacity, and latent heat) were also calculated within the quasi-harmonic approximation. Overall good agreement is observed between the computed thermodynamic properties and the scarce experimental data available for these materials.