Abstract
Studying the mechanical behavior of heat storage media is vital in the safety and design of most sensible and borehole thermal energy storage systems, which are normally built as part of the sub-structure of buildings with load bearing capabilities. In spite of its importance on the efficiency and performance of heat energy storage systems, the mechanical stability and behavior of heat storage materials, mainly at elevated temperatures, has not been given adequate attention in past studies. On this regard, the mechanical behavior of three unsaturated fine- and medium- grained soils from Germany is studied at elevated temperatures, in view of using the soils as a solid sensible heat storage media. The results show a significant dependence of the mechanical behavior of the investigated soils on moisture content and temperature. Furthermore, an increase in shrinkage of the soil specimens with a decrease in the texture of the soils was observed during heating of the soils. The shrinkage behavior is also corroborated with the formation of minor and moderate tensile desiccation cracks of the specimens, which when unaccounted for can result in the lowering of the heat conduction of the heat storage medium, thus lowering the efficiency of the heat storage system.
Highlights
Satisfying the global energy demand with clean and reliable energy is one of the primary challenges of the current century
The results show a significant dependence of the mechanical behavior of the investigated soils on moisture content and temperature
One such example is via household and industrial seasonal storage of thermal energy using borehole thermal energy storage systems, BTES, or solid sensible heat storage systems, where heat or cold from solar collectors or other sources of energy is stored for periods of up to several months for later use (Laing et al 2006 [1]; Laing et al 2012 [2]; Hailemariam et al 2019 [3])
Summary
Satisfying the global energy demand with clean and reliable energy is one of the primary challenges of the current century. The field of geotechnical engineering has been making a significant contribution in solving the energy problem One such example is via household and industrial seasonal storage of thermal energy using borehole thermal energy storage systems, BTES, (e.g. soils) or solid sensible heat storage systems (e.g. cemented porous media), where heat or cold from solar collectors or other sources of energy is stored for periods of up to several months for later use (Laing et al 2006 [1]; Laing et al 2012 [2]; Hailemariam et al 2019 [3]). The soils which are usually expected to have a high degree of water saturation (which will enable them to have a higher heat storage and conduction capacity), will typically exhibit shrinkage and drying at areas closer to the heat exchanger due to their exposure to high temperatures and the subsequent migration of moisture
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
