Thermal energy storage using sensible heat is gaining popularity for integration into fossil-fuel power plants and renewable energy production. Fossil power plants are subjected to varying demand due to public energy needs that requires their systems to ramp up and down daily, resulting in inefficient operation and potential premature fatigue damage. Solar and wind production also varies based on both energy needs and the availability of sun and wind exposure. All of these systems can be improved with the integration of energy storage to enhance the flexibility of supply to meet variable demand. Solid sensible thermal storage using concrete is an emerging option for high-temperature energy storage applications. Concrete is a cementitious construction material composed of cement paste, varying aggregates, and admixtures. It is widely available, can be reinforced to accommodate a variety of loads, and is relatively low cost relative to other solid or chemical energy storage medium. The long-term durability of concrete at high temperatures has been explored in furnace experiments up to 500℃ \[1\]. John et al. \[2\] developed procedures to produce thermal energy storage with economical concrete mixtures that operate at temperatures up to 600℃. Moreover, Wu et al. \[3\] and Salomoni et al. \[4\] developed a series of simplified procedures for a modular design using computational analysis.

Transient thermal and mechanical analyses are simulated via coupled finite element models to study the thermo-mechanical performance of cylindrical concrete block under thermal loadings that are representative of energy storage operation in power plants. Lab-scale scale experiments were performed on normal weight concrete (NWC) cylinders with 100-mm diameter and 200-mm length. Temperature-dependent thermal and mechanical properties per the published literature are utilized. Using a digitally controlled oven, the surface temperature of the cylinder is increased from ambient (\~20℃) to 500℃ and then back to ambient using several rates of temperature increase and decrease. Observations of the spatial and temporal temperature increases, as well as the post-test cracking, are used to validate finite element simulations.

The models are then modified to simulate a TES application with the temperature increase instead applied at the interior surface of a hole running through the longitudinal center of the cylinder. In an actual TES system, energy would be injected into the concrete medium using conduits with heated fluid or other metallic heating elements – the longitudinal hole provides a simple representation of this heating. The present study varies the heating rates (5-, 10- and 24-hour heating periods) and heating cycles (including heating, soaking, and cooling) for a fixed concrete module geometry. In the TES simulation case, different dimensions of the center hole are also examined. The thermal distribution throughout the concrete module, differential thermal expansions, maximum principal stresses during heating, and residual stresses following several heat cycles are observed as a function of time. This study provides insight into the mechanical response and potential reinforcing needs for concrete modules subjected to representative TES heating regimes.

References:

\[1\]      D. Laing, W.-D. Steinmann, M. Fiß, R. Tamme, T. Brand, and C. Bahl, “Solid Media Thermal Storage Development and Analysis of Modular Storage Operation Concepts for Parabolic Trough Power Plants,” *J. Sol. Energy Eng.*, vol. 130, no. 1, p. 011006, 2008.

\[2\]      E. John, M. Hale, and P. Selvam, “Concrete as a thermal energy storage medium for thermocline solar energy storage systems,” *Solar Energy*, vol. 96, pp. 194–204, Oct. 2013.

\[3\]      M. Wu, M. Li, C. Xu, Y. He, and W. Tao, “The impact of concrete structure on the thermal performance of the dual-media thermocline thermal storage tank using concrete as the solid medium,” *Applied Energy*, vol. 113, pp. 1363–1371, Jan. 2014.

 \[4\]     V. A. Salomoni *et al.*, “Thermal storage of sensible heat using concrete modules in solar power plants,” *Solar Energy*, vol. 103, pp. 303–315, May 2014.


Mechanical Performance of Concrete Thermal Energy Storage Subject to Operating Thermal Demands

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.