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Development of low-cost inorganic salt hydrate as a thermochemical energy storage material

Mamani, V and Gutierrez Rojas, Andrea Lucia and Ushak, S (2018) Development of low-cost inorganic salt hydrate as a thermochemical energy storage material. Solar Energy Materials and Solar Cells. Elsevier. DOI: 10.1016/j.solmat.2017.10.021 ISBN 0927-0248 ISSN 0927-0248

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Official URL: https://www.journals.elsevier.com/solar-energy-materials-and-solar-cells


Thermochemical storage is based on a reversible chemical reaction; energy can be stored when an endothermic chemical reaction occurs and then, energy is released when it is reversed in an exothermic reaction. According to literature and based on the energy storage density (esd), MgCl2·6H2O is a promising candidate material for thermochemical energy storage. Bischofite is an inorganic salt obtained as a by-product material from extraction processes of non-metallic minerals, from Salar de Atacama in Chile, containing approximately 95% of MgCl2·6H2O. Thus, the purpose of this study was to characterize the dehydration reaction of bischofite ore, studied as a low-cost thermochemical storage material. Thermogravimetric data for bischofite were obtained using a TGA instrument coupled to a DSC, at four different isotherms 70 °C, 80 °C, 90 °C and 100 °C. The results of conversion reaction (alpha-t) from the thermal dehydration experiments, demonstrated the first phase of dehydration with the loss of two water molecules. The study showed a typical sigmoid curve with a significant acceleration in the conversion at the beginning of the reaction until it reaches a maximum rate, where the curve keeps constant. The same behavior was observed for all the temperatures used. The kinetics of bischofite dehydration model was determined using the isothermal kinetics method. For this, the thermogravimetric data were fitted to the most used kinetic models (D, F, R, A) and then their respective correlation coefficients R were evaluated. The results indicated that the dehydration reaction of bischofite was described by the kinetics of chemical reaction of cylindrical particles R2. The rate of dehydration reaction and esd of bischofite are lower as compared to synthetic MgCl2·6H2O, at temperatures higher than 80 °C. However, the cost of materials to store 1 MJ of energy is three times lower for bischofite, which is an evident advantage to promote the reuse of this material left as waste by the non-metallic industry.

Item URL in elib:https://elib.dlr.de/116536/
Document Type:Article
Title:Development of low-cost inorganic salt hydrate as a thermochemical energy storage material
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Mamani, VUniversity of AntofagastaUNSPECIFIED
Gutierrez Rojas, Andrea LuciaAndrea.GutierrezRojas (at) dlr.dehttps://orcid.org/0000-0002-6313-8264
Ushak, Ssvetlana.ushak (at) uantof.clUNSPECIFIED
Journal or Publication Title:Solar Energy Materials and Solar Cells
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
DOI :10.1016/j.solmat.2017.10.021
EditorsEmailEditor's ORCID iD
Keywords:Thermochemical storage material; Bischofite; Isothermal kinetics; Dehydration reaction; Salt hydrate
HGF - Research field:Energy
HGF - Program:Storage and Cross-linked Infrastructures
HGF - Program Themes:Thermal Energy Storage
DLR - Research area:Energy
DLR - Program:E SP - Energy Storage
DLR - Research theme (Project):E - Thermochemical Processes (Storage)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Thermal Process Technology
Deposited By: Gutierrez Rojas, Andrea Lucia
Deposited On:16 Jan 2018 15:34
Last Modified:07 Feb 2020 13:25

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