Projects / Programmes
High-Performance Nanostructured Coatings ? breakthrough in concentrated solar power
| Code |
Science |
Field |
Subfield |
| 2.04.01 |
Engineering sciences and technologies |
Materials science and technology |
Inorganic nonmetallic materials |
| Code |
Science |
Field |
| T150 |
Technological sciences |
Material technology |
| Code |
Science |
Field |
| 2.05 |
Engineering and Technology |
Materials engineering |
Concentrating solar power, absorber, Spectrally selective, Hightemperature coatings, spinel and cermet pigments, low thermal emittance
Researchers (18)
Organisations (4)
Abstract
Proposed research project in the frame of consortium: National Institute of Chemistry NIC, Institute Jožef Stefan (IJS), University of Nova Gorica (UNG) and Faculty of Health Sciences (ZF) with the help of Hebrew University, Israel and Nanyang Technological University of Singapore will deal with the development of Spectrally Selective Coatings (SSC) for Concentrated Solar Power (CSP) plants. Coatings are based upon stable inorganic nano-materials, especially on transition oxide materials prepared by inventive “bottom-up” approach, used as solar absorber materials for central tower technology, where absorber is heated by reflected sun with more than ten thousand mirrors. SSC are used under atmospheric conditions at 750°C, consequently the longevity of SSC coatings is one of the most important issues for optimal CSP plant operation. As the CSP construction duration last at least five years, maintenance of clean absorber surface during construction and before the first run is very important.
State of the art solar absorber coatings for CSP with the central tower technology are nowadays non-selective coatings. Weakness of mentioned coatings is its high thermal emittance, resulted in large energy loss by radiation. NIC has in the frame of several projects with industrial partners pointed out possibilities for preparation of SSC by the use of different pigments and temperature stable binders on metallic substrates, especially on Inconel.
Needs of the market: New generation of CSP targets are to improve the efficiency of operation and at the same time extend the service late in to the night time. In this field, there is a complete lack of technology for the SSC. Crucial to increase the efficiency is to reduce the thermal emissivity of absorber coatings. Mass production of the coatings on robust industrial receivers, larger than 10 m2, is not possible with expensive vacuum deposition processes, so inventive coating technologies that enable the production by simple procedures, with a reasonable final price of the products, are indispensable.
Objectives are to perform basic research on new technology for the production of advanced SSC, with high solar absorption and low thermal emissivity, which allows economical production of temperature and oxidation resistant coatings at CSP operation temperature on special steel alloy, after extreme load on the field. The technology feasibility will be displayed on a laboratory scale. Developed technology must be scalable and appropriate for the mass production.
Main goals:
development and preparation of a bunch spinel pigments based on oxides of transition metals;
preparation and characterization of anti-corrosion dense layer with a low thermal emissivity;
preparation and characterization of the SSC absorber layer;
life time assessment of SSC;
preparation and characterization of anti-soiling coatings.
Expected results: The project offers a complete solution for the preparation of SSC for CSP at laboratory scale and at the same time gives an opportunity to understand the new synthesized nano-materials before and after thermal load, which is required to explain the stability of optical and mechanical properties for functional materials. With the help of modern analytical techniques, we will try to clarify the materials transformation under thermal load and improve the functioning of the prepared SSC. By applying thin coatings, which are distinguished by high water repellence and anti-soiling properties, we will contribute to the conservation of SSC prior the first run of CSP. We believe that our “bottom-up” approach will result, with the results proved, that it is possible to prepare a heat-resistant SSC using pre-prepared pigments and simple deposition techniques. These studies are necessary, even though this project is the fundamental nature of that show real opportunities for SSC progress for CSP and at the same time encourage interest of the industry for high-temperature SSC.
Significance for science
The scope of the proposed project is the development and implementation of SSC for CSP with CT technology from transition metal oxides on metallic substrates. CSP, with CT technology, gain in past, with new projects under construction, high attention. This project, by “bottom-up” approach, is strongly oriented towards the development of pigments, with spectrally selective properties, used as SSC for CSP therefore, it is expected that this new synthesis route will enable the deposition of the pigment coatings by mass deposition techniques (spray coating). We expect that a suitable platform of materials needed for the development of new SSC with better optical and thermal properties will be established. Moreover, the development of coatings from preprepared pigments with solar selective properties and other desired properties is of general importance for solar energy harvesting, and also very important for the wider use of “green” technologies. In comparison with standard high solar absorptivity coatings (HAS) or high temperature annealed HSA coatings the technology proposed in the project should enable easier fabrication and lower price together with demonstration of higher efficiency. Surprisingly, SSC coatings for high temperature absorbers working at atmospheric conditions are not yet available on the market, the main reasons being the following: insufficient knowledge about the physical and chemical processes that influence the main characteristics of spectrally selective coating at temperature over 700°C during their operation, unresolved problems concerning the preparation of high density thin coatings acting as barrier coatings and at the same time possess low thermal emittance, the preparation of pigments with spectrally selective properties, and, most importantly, the lack of the appropriate binder with low thermal emittance property, high thermal conductivity and excellent mechanical properties (abrasion and crack resistance), that enable the construction of SSC with a long service life. The foreseen research within the project will be aimed at performing targeted experiments that will enable us to determine and monitor the most important properties of spectrally selective coatings for high temperature application: the development of transition oxide pigments with metallic inclusions, enabling the preparation of SSC on metallic substrates, exhibiting high density, particle interconnectivity and high solar harvesting efficiency. Coatings should be tested in next stage by accelerated testing procedure and to understand their failure modes under operation and, finally, to predict service life time. A high impact and relevance of the project is foreseen due to the aim of transferring the knowledge of SSC technology between various partners. Including those, who want to explore also potential of such coatings for renewable energy harvesting (Hebrew University under new program (NEW-CREATE) with Nanyang Technology University, Singapore).
Significance for the country
Existing energy production plans in many states address the need to reduce greenhouse gas emissions and air pollution, keep energy prices low, and foster job creation. By the year 2050 end-use U.S. all-purpose load would be met with ~30.9% onshore wind, ~19.1% offshore wind, ~30.7% utility-scale photovoltaics (PV), ~7.2% rooftop PV, ~7.3% concentrated solar power (CSP) with storage, ~1.25% geothermal power, ~0.37% wave power, ~0.14% tidal power, and ~3.01% hydroelectric power. Based on a parallel grid integration study, an additional 4.4% and 7.2% of power beyond that needed for annual loads would be supplied by CSP with storage and solar thermal for heat, respectively, for peaking and grid stability.59 As it is known that 1 km2 of desert land may produce 200 – 300 GWhel/year and we can avoid by this harvesting of electrical energy 200000 tons of CO2/year concentrated power plants play an important role in economy and society. It is clear that the overall turnover of paint industry in Slovenia will not change impressively annually by producing the spectrally selective paints, but Slovenian society can gain a lot, by royalties and success fees from development of SSC. It is clear that intelligent control of the solar light harvesting and its coating longevity are a complex problems requiring basic research, its verification in applications, demonstration with social, political and legislative aspects on the national and EU level, appropriate funding and budget. Effective collaboration between different laboratories and industries is needed to reach practically usable products with high scientific added values stemming from the development of novel functional materials based on nanoscience. This will be unquestionably achieved in this project: NIC focuses on basic research and the production of functional nanostructured pigment coatings, accelerated testing and modelling of coating life time. In addition, NIC will develop low cost coatings with anti-soiling effect suitable for protection of absorber surface before first run. IJS (and also NIC) will be active on barrier coating and binder with low thermal emissivity research and UNG on the development of the methods for evaluation of coatings thermal conductivity. The developed technology may lower energy losses on CSP absorbers, lower CO2 emission and save the environment. The coordinative action of these partners will provide a suitable platform of knowledge to build, construct end evaluate SSC for CSP enabling intelligent control of light harvesting in future applicative projects, also at EU level. The importance of pigments for high temperature SSC coatings lies also in the fact that investigation of preparation of these pigment dispersions can significantly contribute to the level of knowledge on the preparation of pigment dispersions, needed also for other technological fields, for example production of coatings for space applications.
Most important scientific results
Interim report,
final report
Most important socioeconomically and culturally relevant results
Interim report,
final report
