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Experimental investigation of the thermal and mechanical stability of rocks for high-temperature thermal-energy storage

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Becattini Viola, Motmans Thomas, Zappone Alba, Madonna Claudio, Haselbacher Andreas, Steinfeld Aldo,
Project Design and Optimization of High-Temperature Combined Sensible/Latent-Heat Storage
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Original article (peer-reviewed)

Journal Applied Energy
Volume (Issue) 203
Page(s) 373 - 389
Title of proceedings Applied Energy
DOI 10.1016/j.apenergy.2017.06.025

Open Access

URL http://doi.org/10.1016/j.apenergy.2017.06.025
Type of Open Access Publisher (Gold Open Access)

Abstract

Six types of rocks of Alpine origin were investigated for their suitability for high-temperature packed-bed thermal-energy storage. The rocks were thermally cycled in laboratory furnaces between about 100 C and 600 C with a heating rate of 2.6 C/min and assessed in terms of their specific heat capacity and porosity as well as the degree of cracking, fracturing, and disintegration. Thermal cycling was found to lead to decreases in the specific heat capacity and increases in the porosity of the rocks. These changes are explained by physical and chemical reactions such as mineral dehydration, deserpentinization, decar- bonation, and the quartz-inversion reaction. Simulations of a 23 MWh industrial-scale thermal-energy storage show that the decrease in the specific heat capacity does not have a significant impact on the effective storage capacity, utilization factor, and exergy efficiency. To avoid fracturing of rocks, foliated rocks and rocks rich in calcite and/or quartz, such as limestones and sandstones, are found to be unsuit- able when exposed to temperatures higher than about 600 C or 573 C, respectively. Mafic rocks, felsic rocks, serpentinite, and quartz-rich conglomerates are judged to be suitable for high-temperature thermal-energy storage.
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