A DFT based equilibrium study of a chemical mixture Tachyhydrite and their lower hydrates for long term heat storage

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Abstract

Chloride based salt hydrates are promising materials for seasonal heat storage.
However, hydrolysis, a side reaction, deteriorates, their cycle stability. To improve the kinetics
and durability, we have investigated the optimum operating conditions of a chemical mixture of CaCl2 and MgCl2 hydrates. In this study, we apply a GGA-DFT to gain insight into the various hydrates of CaMg2Cl6. We have obtained the structural properties, atomic charges and vibrational frequencies of CaMg2Cl6 hydrates. The entropic contribution and the enthalpy change are quantified from ground state energy and harmonic frequencies. Subsequently, the change in the Gibbs free energy of thermolysis was obtained under a wide range of temperature and pressure. The equilibrium product concentration of thermolysis can be used to design the seasonal heat storage system under different operating conditions.
Original languageEnglish
Article number032003
Pages (from-to)1-9
Number of pages9
JournalJournal of Physics: Conference Series
Volume745
DOIs
Publication statusPublished - 2016
Event7th European Thermal-Sciences Conference (Eurotherm2016), 19-23 June 2016, Krakow, Poland - Krakow, Poland
Duration: 19 Jun 201623 Jun 2016
http://www.eurotherm2016.agh.edu.pl/

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heat storage
hydrates
Gibbs free energy
durability
hydrolysis
enthalpy
chlorides
salts
harmonics
cycles
ground state
products
temperature
energy

Cite this

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title = "A DFT based equilibrium study of a chemical mixture Tachyhydrite and their lower hydrates for long term heat storage",
abstract = "Chloride based salt hydrates are promising materials for seasonal heat storage.However, hydrolysis, a side reaction, deteriorates, their cycle stability. To improve the kineticsand durability, we have investigated the optimum operating conditions of a chemical mixture of CaCl2 and MgCl2 hydrates. In this study, we apply a GGA-DFT to gain insight into the various hydrates of CaMg2Cl6. We have obtained the structural properties, atomic charges and vibrational frequencies of CaMg2Cl6 hydrates. The entropic contribution and the enthalpy change are quantified from ground state energy and harmonic frequencies. Subsequently, the change in the Gibbs free energy of thermolysis was obtained under a wide range of temperature and pressure. The equilibrium product concentration of thermolysis can be used to design the seasonal heat storage system under different operating conditions.",
author = "A.D. Pathak and {Gaastra - Nedea}, S.V. and H.A. Zondag and C.C.M. Rindt and D.M.J. Smeulders",
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TY - JOUR

T1 - A DFT based equilibrium study of a chemical mixture Tachyhydrite and their lower hydrates for long term heat storage

AU - Pathak, A.D.

AU - Gaastra - Nedea, S.V.

AU - Zondag, H.A.

AU - Rindt, C.C.M.

AU - Smeulders, D.M.J.

PY - 2016

Y1 - 2016

N2 - Chloride based salt hydrates are promising materials for seasonal heat storage.However, hydrolysis, a side reaction, deteriorates, their cycle stability. To improve the kineticsand durability, we have investigated the optimum operating conditions of a chemical mixture of CaCl2 and MgCl2 hydrates. In this study, we apply a GGA-DFT to gain insight into the various hydrates of CaMg2Cl6. We have obtained the structural properties, atomic charges and vibrational frequencies of CaMg2Cl6 hydrates. The entropic contribution and the enthalpy change are quantified from ground state energy and harmonic frequencies. Subsequently, the change in the Gibbs free energy of thermolysis was obtained under a wide range of temperature and pressure. The equilibrium product concentration of thermolysis can be used to design the seasonal heat storage system under different operating conditions.

AB - Chloride based salt hydrates are promising materials for seasonal heat storage.However, hydrolysis, a side reaction, deteriorates, their cycle stability. To improve the kineticsand durability, we have investigated the optimum operating conditions of a chemical mixture of CaCl2 and MgCl2 hydrates. In this study, we apply a GGA-DFT to gain insight into the various hydrates of CaMg2Cl6. We have obtained the structural properties, atomic charges and vibrational frequencies of CaMg2Cl6 hydrates. The entropic contribution and the enthalpy change are quantified from ground state energy and harmonic frequencies. Subsequently, the change in the Gibbs free energy of thermolysis was obtained under a wide range of temperature and pressure. The equilibrium product concentration of thermolysis can be used to design the seasonal heat storage system under different operating conditions.

U2 - 10.1088/1742-6596/745/3/032003

DO - 10.1088/1742-6596/745/3/032003

M3 - Article

VL - 745

SP - 1

EP - 9

JO - Journal of Physics: Conference Series

JF - Journal of Physics: Conference Series

SN - 1742-6588

M1 - 032003

ER -