Research progress and trends on the use of concrete as thermal energy storage material through bibliometric analysis

A landmark review of concrete as thermal energy storage material is presented through a bibliometric analysis approach. This study shows influential literature and the current relevant research directions. Geographical source and the identification of the significant publications enable determining the leading authors and research groups of the topic. The methodology is based on an accurately defined query, composed of remarkable keywords for the study. Two queries are set out, the first one from a holistic point of view of the topic, while the second one has a special consideration on concrete as TES under high-temperature conditions. Most part of the literature research pays attention to concrete applications in buildings, while other applications such as solar energy are in the rear face. Throughout the years, great interest in latent heat storage technology is observed using phase change material (PCM), implementing them in concrete mixtures or in other formats integrated into a building component. Despite the fact that the area of research is currently in prominent development, some literature gaps and new research directions are identified. Concepts such as climate change mitigation, concrete components, maintenance, are possible in-progress initiatives which need to be further studied.This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018–093849-B-C31 - MCIU/AEI/FEDER, UE) and by the Ministerio de Ciencia, Innovación y Universidades - Agencia Estatal de Investigación (AEI) (RED2018–102431-T). The authors at the University of Lleida would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia program. A.L. Pisello thanks the Italian project SOS-CITTA’ supported by Fondazione Cassa di Risparmio di Perugia under grant agreement No. 2018.0499.026

Experimental study and comparison of different fully transparent laminated glass beam designs

Laminated glass beams without metallic or polymeric reinforcements generally lack post-breakage strength and ductility. This paper aims to perform a comparative study by testing five different fully transparent laminated glass beam designs in order to see how parameters such as the number and thickness of glass sheets (3 x 10 mm or 5 x 6 mm), the interlayer material (PVB Clear or SentryGlas), and the thermal treatment of glass (annealed or heat-strengthened) affect the pre-breakage performance and post-breakage safety. A buckling analysis is also performed using a numerical model with ABAQUS CAE. The study includes a comparison between the results of different experimental mechanical tests on laminated glass beams, including the tests presented in this paper, as well as other tests found in the literature. All designs presented a linear elastic behaviour until initial breakage. The interlayer material mainly affected the crack shape of laminated glass beams. Beams with five sheets of annealed glass had a more progressive breakage, and therefore a safer behaviour, than beams with three sheets of annealed or heat-strengthened glass.The work was partially funded by CRISTEC with CDTI funds (IDI-20160588). The authors at the University of Lleida would like to thank the Catalan Government for the quality accreditation given to their research group GREiA (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme. The financing support given by the Spanish Ministry of Economy and Competitiveness through the project BIA2014-53774-R is gratefully appreciated. Xavier Centelles would like to thank University of Lleida for his research fellowship and to the University of Oviedo for hosting his secondment during 2019. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature

Effect of the curing process on the thermomechanical properties of calcium aluminate cement paste under thermal cycling at high temperatures for thermal energy storage applications

Future perspectives to improve the energy efficiency of concentrating solar power (CSP) plants are focused on increasing temperatures above 600 ◦C. Among the different components of a CSP plant, the thermal energy storage (TES) medium must withstand high operating temperatures. Concrete was identified as an exciting candidate for its mechanical and thermal properties, needing further experimental research about this specific application. A fundamental concrete element is the cement binder, bringing cohesion to the composite components. As a requisite, the cement needs to be heat-resistant, and calcium aluminate cement (CAC) suits this demand. This cement is characterised by curing temperature-driven crystallisation changes, triggering an alteration of material properties. Considering that at 60 ◦C, the metastable hexagonal crystallisation is converted into a stable cubic crystallisation, seven curing cases were proposed in this study. After the curing process, thermo-mechanical properties of calcium aluminate cement paste were tested before and after thermal cycles from 290 ◦C to 650 ◦C. The results showed that, despite thermal cycling, the immediate hydration at 60 ◦C results in a higher thermal conductivity and compressive strength than standard curing at 20 ◦C.novaci´on - Agencia Estatal de Investigaci´on (PID2021-123511OB-C31 - MCIN/AEI/10.13039/501100011033) and by the Ministerio de Ciencia, Innovaci´on y Universidades - Agencia Estatal de Investigaci´on (AEI) (RED2018-102431-T). The authors at University of Lleida would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme. Laura Boquera acknowledgments are due to the PhD school in Energy and Sustainable Development from University of Perugia. Laura Boquera would like to acknowledge the financial support provided by UNIPG –CIRIAF InpathTES project. The authors also thank Ciments Molins industrial that provided the material to make possible this experimental research. Financial support of the UNIPG-CIRIAF team has been achieved from the Italian Ministry of University and Research (MUR) in the framework of the Project FISR 2019 “Eco Earth” (code 00245) that is gratefully acknowledged