Projects / Programmes
Novel Thermal Energy Storage Materials
| Code |
Science |
Field |
Subfield |
| 1.04.03 |
Natural sciences and mathematics |
Chemistry |
Inorganic chemistry |
| Code |
Science |
Field |
| P003 |
Natural sciences and mathematics |
Chemistry |
| Code |
Science |
Field |
| 1.04 |
Natural Sciences |
Chemical sciences |
thermal energy storage, adsorption, sorbtion materials, zeolite, aluminophosphate, mesoporous silicates, MOF, composites, materials engineering, materials characterizations,
Researchers (8)
Organisations (1)
| no. |
Code |
Research organisation |
City |
Registration number |
No. of publicationsNo. of publications |
| 1. |
0104 |
National Institute of Chemistry |
Ljubljana |
5051592000 |
21,007 |
Abstract
Detailed knowledge of thermo-chemical properties of materials and how they change with temperature is fundamental to almost every application where materials are involved. An important aspect of research focuses on studying the role of materials' structure in the determination of their thermal properties. Energy density, thermal power and the temperature levels for charging and discharging are describing the properties of thermal energy storage. A primary aim of our research is the study of the dependency between the structure of novel microporous and mesoporous materials and their thermal storage abilities. These novel microporous and mesoporous materials can be classified as nanostructured solids consisting of primary nanoparticles with high surface area. Such systems usually exhibit enhanced transport properties. An important aspect is also the relation between nanostructured system and its characteristic thermal transport. Our goal is to establish and understand these dependencies in order to develop, improve, and ultimately taylor-make specific materials with particular energy storage capabilities.
The objective of this investigation is a development of a new thermal energy storage system, e.g. a synthesis and characterization of novel sorption materials. These novel materials, prepared hydrothermally, will comprise microporous and mesoporous solids and their composites. Microporous and mesoporous materials functionality will be multiplied by the incorporation of hygroscopic inorganic salt hydrates, such as CaCl2 and metal active sites into the pores. The modification of the microporous and mesoporous matrices will be obtained by the post-functionalization procedures: wet impregnation and deposition. Materials will be characterized by a variety of modern instrumental techniques in order to characterize their crystalline structure, phase purity and microporous and mesoporous structural arrangement within the porous network. Thermal stability, dehydration dynamics and the resulting changes will also be investigated. The morphology of products as well as other important physical characteristics, such as pore arrangement, particle size distribution, and adsorption isotherms, will be determined. The proposed project is focused on the optimization of the adsorbent design to increase the storage density, defined as energy stored per unit volume, and storage efficiency, defined as the fraction of energy recoverable after the storage period, as well as the synthesis of new materials with detailed study of their structural/thermo chemical properties. The research will be divided: (1) the synthesis of different hydrophilic microporous and mesoporous solids and their composites, consisting of a microporous and mesoporous network and a hygroscopic inorganic salt impregnated in the pore system for water-based systems, (2) structural characterization of synthesized composite and sorbent materials and (3) study of thermo chemical properties of new materials. Later studies will be performed in the Bavarian Center for Applied Energy Research by group for Heat Storage Systems.
Development of new thermal energy storage systems is extremely important for wider solar energy and waste heat utilization for domestic and industrial use. By improving the effectiveness of thermal storage, we can improve the effectiveness of most of energy conversion and utilization technologies. This is especially important in the case of utilization of renewable energy and waste heat, when there is a mismatch between the heat availability and heat delivery. Therefore, any improvement to the performance, lifetime or costs of thermal storage will positively affect every renewable heating system globally. The gained knowledge and experience on the thermal storage will enable our group to actively cooperate in international project IEA Task 42/24 (2009–2012).
Significance for science
For housing heating Europe consumes very high share of fossil fuels. This is related to atmospheric pollution and high CO2 content. Thermal energy storage is a key part of all newer systems for heating and cooling. Development of materials for storage technologies with improved performance, durability and system reliability, and lower costs has a positive effect on the development of other systems with renewable energy sources. In order to improve storage energy technologies materials used have by far the major role. In this project, we focused on the development of new adsorption materials and on the development of new systems for thermal energy storage (heat storage is based on reversible physico-chemical process: sorption / desorption of water in porous solid adsorbents). We focused on hydrothermal synthesis and characterization of new sorption microporous and mesoporous materials and their composites, on the structure of these materials and their ability to store thermal energy. We also functionalized porous structure with hygroscopic hydrates of inorganic salts, such as CaCl2. The materials were characterized with many modern instrumental techniques in order to determine their crystalline structure, phase purity and structural arrangements of micro / mesoporous frameworks. We also studied thermal stability of the materials prepared and dynamics of the dehydration and the related structural changes. We have also optimized the structure of adsorbents in order to increase the density of stored energy and to increase the storage efficiency. Within a three-year research project we fully achieved and even surpassed the research objectives. We have developed several new promising systems for storing thermal energy at low (solar energy) and medium temperatures (up to 350 deg. C), with the synthesis and structural characterization of new sorption materials with water as adsorption agent. We developed a new microporous aluminophosphate APO-tric adsorbent for seasonal storage of heat in the summer and to release heat in winter via the controlled adsorption/desorption of water. Comparative thermogravimetric and a calorimetric study of sorption of water in the aluminophosphate materials with small pore size (SAPO-34, AlPO4-18 and APO-TRIC) have shown, that the formation of highly ordered water clusters is the driving force for sudden sorption of water in a narrow pressure range, which is required for use in storage systems and is essential for effective heat storage. This material has attracted considerable attention and the results of these studies were published in the prestigious journal Advanced Functional Materials. We published our research results in three scientific papers in journals with IF from 3.4 to 9.8. The results were also presented at international conferences and as invited lectures at conferences and universities. Completed basic project has also an applied value. We have developed a synthetic procedure for the preparation of zeolite NaX and transferred it to a semi-industrial level in the factory Silkem in Kidričevo. Upgrade from 250 ml to 1300-liter reactor was successful and the granular zeolite NaX is well crystalline. There are chances of implementation in the sorption-storage systems based on this granular zeolite. Experts from Slovenia and Austria are working on the technology. Since 2013, Dr. Alenka Ristić is chairing the working group on engineering materials within the IEA (International Energy Agency) SHC ECES joint Task / Annex 42/29 "Compact Thermal Energy Storage: Material Development for System Integration".
Significance for the country
For Slovenia the results of materials research to store heat are extremely important. In developed countries today already over 50% of the energy is consumed for heating and cooling buildings in households and in industry. If the source of energy for heating at an even greater extent could be the sun, that would bring larger savings in energy production, and by far the largest reduction in CO2 emissions. Study of materials for heat storage is helping this issue, namely how stored solar energy that we have available through the warm part of the year can be used for heating in the cold part of the year. With our work on the project and in cooperation with other European research groups (UAE Bayern, Fraunhofer ISE Frieburg), we help to resolve this issue. Completed basic project has also an applied value. We have developed a synthetic procedure for the preparation of zeolite NaX and transferred it to a semi-industrial level in the factory Silkem in Kidričevo. Upgrade from 250 ml to 1300-liter reactor was successful and the granular zeolite NaX is well crystalline. There are chances of implementation in the sorption-storage systems based on this granular zeolite. Experts from Slovenia and Austria are working on the technology. In recent years, Dr. Alenka Ristić is very active in the International Energy Agency - IEA association, specifically in the IEA SHC ECES joint Task / Annex 42/24 (2009-2012) and 42/29 (2013-2015) »Compact Thermal Energy Storage Material Development for System Integration". In October 2013 she also organized the 10th International expert meeting in the framework of the IEA SHC ECES joint Task / Annex 42/29 "Compact Thermal Energy Storage: Material Development for System Integration" at the National Institute of Chemistry in Ljubljana. The meeting was attended by 35 experts from around the world. For the promotion of Slovenia and the Slovenian science her active participation in the IEA association in recent years is extremely important. Dr. Tadeja Birsa Čelič in the context of her doctoral thesis Development of porous metal-organic adsorbents for the storage of gases and of heat studied metal-organic porous materials. These are crystalline materials made of metal oxide units, which are linked with organic ligands. These materials are characterized by an extremely large specific surface area and low density, which makes them very interesting for hydrogen storage, the storage and separation of carbon dioxide and methane, as well as for energy storage. Nataša Zabukovec Logar in an invited lecture at the First Euro-Asian Zeolite Conference (Macau, January 2013) introduced the basic concepts of heat storage, with emphasis on the sorption heat storage in the aluminophosphate and metal-organic porous materials. We prepared promising aqueous composite sorbents for storing solar energy. With the wet impregnation with a solution of calcium chloride two different composites for sorption of water were prepared, one with random mesostructural matrix of iron silicate, and the other with an ordered mezoporous silicate matrix. Their structural and water sorption properties were presented at the 5th International Symposium of Advanced Micro-and Mesoporous Materials in Varna 2013. The new storage tanks will allow permanent storage of heat - in an article by Nataša Zabukovec Logar in the business newspaper from Slovenia. In a popular way the field of energy storage, the latest technologies and our own research in this area have been presented. All the above-mentioned publications of the results of our research are very important for Slovenia, because they show that we are among the countries where the research of the materials for heat energy storage is at the highest world level.
Most important scientific results
Annual report
2010,
2011,
2012,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2010,
2011,
2012,
final report,
complete report on dLib.si
