High-performance ultra-low-carbon Geopolymer heat Battery for thermochemical energy storage in net-zero buildings (GeoBattery)
Lead Research Organisation:
University of Bath
Department Name: Architecture and Civil Engineering
Abstract
Space heating currently accounts for 25% of the UK's energy consumption and 17% of its carbon emissions. The effective and efficient recovery, storage, and reuse of waste heat, together with renewable energy, play indispensable roles in decarbonisation of heating in buildings. The thermochemical energy storage materials possess the highest volumetric energy density comparing to phase change and sensible heat storage materials. However, the design and manufacture of thermochemical energy storage materials are still facing the challenges of high cost, low sustainability, and limited heating power. There also lacks fundamental understandings of the properties of materials that control the cyclic energy storage performances and structural stabilities. These have brought significant challenges to optimisation and implementation of the thermochemical energy storage techniques for domestic application.
This project adopts novel research approaches for civil engineering materials to tackle these standing challenges faced by developing thermochemical energy storage materials. Versatile high-performance heat battery materials will be developed from sustainable low-cost civil engineering material geopolymers. Lightweight geopolymer composite materials with enhanced heat and mass transport properties and thermochemical energy storage capacity will be developed through green synthesis routes. The first structural stability assessment model for predicting the service cycle life of heat battery materials will be proposed from the extended chemo-mechanical salt damage model for inorganic porous building materials. The materials fabrication technology and fundamental understanding of the degradation mechanism developed in this project will be transferable to versatile "salt-in-matrix" TCES composites. The outcomes developed from this project will drastically improve the sustainability and resilience of thermal energy storage technologies, for decarbonisation of heating in existing and new-built buildings.
This project adopts novel research approaches for civil engineering materials to tackle these standing challenges faced by developing thermochemical energy storage materials. Versatile high-performance heat battery materials will be developed from sustainable low-cost civil engineering material geopolymers. Lightweight geopolymer composite materials with enhanced heat and mass transport properties and thermochemical energy storage capacity will be developed through green synthesis routes. The first structural stability assessment model for predicting the service cycle life of heat battery materials will be proposed from the extended chemo-mechanical salt damage model for inorganic porous building materials. The materials fabrication technology and fundamental understanding of the degradation mechanism developed in this project will be transferable to versatile "salt-in-matrix" TCES composites. The outcomes developed from this project will drastically improve the sustainability and resilience of thermal energy storage technologies, for decarbonisation of heating in existing and new-built buildings.
Publications
Ke X
(2022)
Atomic-scale characterisation of sodium aluminosilicate hydrates (N-A-S-H) and Mg-substituted N(-M)-A-S-H using XANES
in Applied Geochemistry
Reynolds J
(2024)
Optimisation of CaCl2 impregnated expanded graphite and alginate matrices - Targeted salt loading
in Energy Conversion and Management
Reynolds J
(2023)
Development and characterisation of an alginate and expanded graphite based composite for thermochemical heat storage
in Journal of Materials Science
| Description | Geopolymer materials are increasingly recognised as critical components for achieving a sustainable future, particularly due to their potential role in enabling efficient and environmentally friendly thermal energy storage solutions. Central to their performance is the N(K)-A-S-H gel, whose properties significantly influence geopolymer behaviour in thermochemical energy storage (TCES) applications. This project has provided substantial new insights into the structure-property correlations of N(K)-A-S-H gels, highlighting the key physical and chemical factors that control their water sorption capacity and kinetics, as well as their thermochemical properties. Furthermore, novel hierarchically porous geopolymer composites were successfully developed using green synthesis routes, resulting in lightweight materials with enhanced performance suitable for advanced heat battery technologies. Important new research questions have emerged, particularly regarding the chemical states of water within geopolymers and their influence on microstructural stability and mechanical integrity, as well as the role of organic additives in tailoring geopolymer properties. The creation of a robust international research network focused on cement-based thermal energy storage has strengthened global collaboration and knowledge exchange. Additionally, the project enhanced research capabilities through active participation in a RILEM initiative, contributing to reviewing the standardised testing methodologies for evaluating phase change materials in cementitious composites, thereby ensuring consistency and advancing international standards in this emerging field. |
| Exploitation Route | The outcomes of this research offer significant opportunities for practical applications in both the construction and energy sectors. In construction, the newly developed lightweight geopolymer materials could be integrated directly into building components, such as walls, roofs, or flooring systems, to store and release heat efficiently, significantly reducing energy consumption and improving indoor comfort. The enhanced understanding of geopolymer stability and durability will enable engineers to design buildings with greater confidence in their long-term performance, thereby accelerating the adoption of sustainable construction materials. For the energy sector, the advanced geopolymer composites developed through this project can serve as high-performance durable binder matrix for synthesising hybrid thermochemical composites, providing effective ways to store renewable energy in the form of heat, thus addressing key challenges in balancing energy supply and demand. The international collaborations established through the project can facilitate further innovation, helping industry partners rapidly incorporate these materials into commercial solutions. Additionally, the standardised testing methods developed and reviewed within the project will support industry-wide adoption and compliance with emerging sustainability regulations and standards. |
| Sectors | Construction Energy |
| Description | Collaboration with Prof. Antonio Caggiano from Università degli Studi di Genova (Itlay) |
| Organisation | University of Genoa |
| Country | Italy |
| Sector | Academic/University |
| PI Contribution | Developed research collaboration with Prof. Antonio Caggiano from Università degli Studi di Genova (Itlay) through the research activity in the RILEM TC-TES technical committee, where Prof. Antonio Caggiano is the committee chair. A joint travel grant proposal has been submitted to the Royal Society International Exchange scheme (submitted 8th March 2023) worth £11,900 (IES\R1\231229) aiming to enable sustained staff exchange in the next two years. |
| Collaborator Contribution | Contributed to the preparation and submission of a joint travel grant proposal (IES\R1\231229). |
| Impact | This is a newly established collaboration, and the planned outputs are: - Fundings for staff exchange (a Royal Society travel grant application has been submitted). - Joint research papers combining experimental research with numerical modelings. |
| Start Year | 2023 |
| Description | Application to Engage Grants 2023 for Science and Engineering & Design (internal funding) |
| Form Of Engagement Activity | Participation in an open day or visit at my research institution |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | An application to the University of Bath's internal Engage Grants 2023 for Science and Engineering & Design has been prepared and submitted by the postdoctoral researcher hired by this project aiming to improve the awareness and knowledge of local school students and the general public about the importance and benefit of domestic thermal energy storage. |
| Year(s) Of Engagement Activity | 2023 |
| Description | Leadership role within the RILEM technical committee 299-TES : Thermal energy storage in cementitious composites |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | The RILEM Technical Committee 299-TES focuses on Thermal Energy Storage (TES) in cementitious composites, aiming to enhance energy efficiency in buildings by incorporating TES capabilities into construction materials. Established in 2020, the committee is led by Dr. Jorge Sanchez Dolado with Dr. Antonio Caggiano as the deputy chair. Their primary goal is to develop a State-of-the-Art (STAR) report, along with technical recommendations and guidelines for experimental characterization, analytical analysis, numerical modeling, and practical applications of TES-enabled cementitious composites. The committee investigates three main TES mechanisms: Sensible Heat Storage (SHS), which relies on temperature variations; Latent Heat Storage (LHS), which utilizes phase change materials (PCMs) to store and release heat during phase transitions; and Thermo-Chemical Storage (TCS), which stores heat through reversible chemical reactions (directly links to this award). By assessing the feasibility of these storage methods in cementitious materials, the committee aims to enhance energy efficiency in buildings, reduce heating and cooling demands, and improve thermal comfort. Key intended outcomes include a comprehensive STAR report detailing current knowledge, standardised experimental methods for assessing TES materials, and technical guidelines for integrating TES into cement-based structures. These findings are expected to support the development of energy-efficient buildings, minimise carbon footprints, and contribute to sustainable construction practices. |
| Year(s) Of Engagement Activity | 2021,2022,2023,2024,2025 |
| URL | https://www.rilem.net/groupe/299-tes-thermal-energy-storage-in-cementitious-composites-422 |
| Description | Organised (workshop chair) the 2nd international workshop on net zero carbon buildings |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | 2nd international workshop on net zero carbon buildings, also under the umbrella of RILEM TC 299-TES, at the University of Bath campus between 24th-25th January 2024. The theme is 'Energy neutral and sustainability in construction and building materials'. The event aims to explore current state-of-the-art and novel advances on topics related to the green deal on construction and building materials. The event hosted 7 esteemed international speakers and 14 student presentations, including Prof. Luisa Cabeza (Editor in chief of Journal of Energy Storage, IF 8.9.) as the keynote speaks. The two-day event was hosted in hybrid form and joined by >30 in-person participants from EU, Canada, and Brazil. This link leads to the workshop webpage. (https://www.rilem.net/agenda/2nd-international-workshop-on-net-zero-carbon-buildings-1585). |
| Year(s) Of Engagement Activity | 2024 |
| URL | https://www.rilem.net/agenda/2nd-international-workshop-on-net-zero-carbon-buildings-1585 |
| Description | Workshop in Genova: Net Zero Carbon Buildings (Dec-2022) |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | A two days workshop in Genova hosted by Prof. Antonio Caggiano. - First day, full-day research presentations (online+in-person) given by international researchers, on thermal energy storage materials including both experimental methods and modeling techniques. - Half day 5th RILEM TC TES research committee meeting, discuss the progress and targets of the planned state-of-the-art book chapter. |
| Year(s) Of Engagement Activity | 2022 |