SUPERSOLAR

Ultra-refractory ceramic absorbers for thermodynamic solar energy generation at high temperature

Principal investigators: Laura Silvestroni, Diletta Sciti

Involved personnel: Luca Zoli, Daniele Dalle Fabbriche, Cesare Melandri

Starting date: 01/03/2013
Duration: 36 months
Total funding: 897.792 €
Call: Futuro in Ricerca, FIRB 2012
Consortium: Istituto Nazionale di Ottica (CNR-INO), Università di Cagliari (UNICA)
Official website: https://lucamerca.wixsite.com/supersolar

Solar thermal technology is a safe, sustainable and cost-effective energy supply. The maximum operating temperatures of solar power plants are usually lower than 800 K because of the rapid degradation of their components. However, the efficiency of solar thermal power plants increases rapidly with increasing working temperatures. Hence, the problem to be solved is the improvement of the receiver stability at high temperatures.

The present proposal lies in this context with fundamental research and development of ceramic materials to be employed in thermal solar energy plants as absorbers operating at temperatures up to 1200 K. The main challenge is the development of materials resisting to damage in air at high temperatures, while keeping good thermal conductivity and favorable radiative properties.

Diborides and carbides of zirconium, hafnium and tantalum (ZrB₂, ZrC, HfB₂, HfC, TaB₂,TaC), are referred to as Ultra-High-Temperature-Ceramics (UHTCs) and are considered the best-emerging materials for applications in aerospace and advanced energy systems (turbine blades, combustors, scramjet engines, nuclear fusion reactors). The increasing interest in these materials is due to their unique combination of properties, including the highest melting points of any group of materials, high strength, high thermal and electrical conductivities and chemical stability. Recently it has been found that most of these compounds also have the characteristic of being intrinsic solar selective, but the understanding of the optical properties of these materials is still very scanty, especially at high temperature. Ultra-high temperature ceramics (UHTCs) have thus the potential to be suited for application in high temperature solar receivers, once their basic properties have been properly investigated and correlated to bulk and surface characteristics. The main goals of SUPERSOLAR, are the development of several UHTCs materials and the study of their fundamental properties. The investigation is mainly concerned with light absorption and emission both at room and high temperatures and their correlation to material parameters such as compositions, porosity and surface finishing with the thermo-mechanical properties, like mechanical strength at room and high temperature, thermal conductivity, oxidation and thermal shock resistance.

Publications & Patents

• Sciti D., Silvestroni L., Mercatelli L., Sans J.-L., Sani E., Suitability of ultra-refractory diboride ceramics as absorbers for solar energy applications, Solar Energy Materials and Solar Cells, 109 (2013), 8-13
• Mercatelli L., Sani E., Jafrancesco D., Sansoni P., Fontani D., Meucci M., Coraggia S., Marconi L., Sans J-L., Beche E., Silvestroni L. and Sciti D., Ultra-Refractory Diboride Ceramics For Solar Plant Receivers, Proceedings of SolarPACES 2013, sept 2013, Las Vegas, USA
• Sani E., Mercatelli L., Sans J-L., Silvestroni L., Sciti D., Porous and dense hafnium and zirconium ultra-high temperature ceramics for solar receivers, Optical Materials, 36 (2) (2013) , 163-168
• Sciti D., Silvestroni L., Sans J-L., Mercatelli L., Meucci M., Sani E., Tantalum diboride-based ceramics for bulk solar absorbers, Solar Energy Materials And Solar Cells, 130 (2014), 208-216
• Sani E., Meucci M., Mercatelli L., Jafrancesco D., Sans J-L., Silvestroni L., Sciti D., Optical properties of boride ultrahigh-temperature ceramics for solar thermal absorbers, Journal of Photonics For Energy, 4 (2014), 045599-1-8
• Sani E., Mercatelli L., Sans J-L., Sciti D., Optical properties of black and white ZrO2 for solar receiver applications, Solar Energy Materials and Solar Cells, 140 (2015), 477-482
• Sani E., Mercatelli L., Meucci M., Balbo A., Silvestroni L., Sciti D., Compositional dependence of optical properties of zirconium, hafnium and tantalum carbides for solar absorber applications, Solar Energy, 131 (2016), 199-207
• Sani E., Mercatelli L., Meucci M., Silvestroni L., Balbo A., Sciti D., Process and composition dependence of optical properties of zirconium, hafnium and tantalum borides for solar receiver applications, Solar Energy Materials and Solar Cells, 155 (2016), 368-377
• Musa C., Licheri R., Orrù R., Cao G., Sciti D., Silvestroni L., Zoli L., Balbo A., Mercatelli L., Meucci M., Sani E., Processing, mechanical and optical properties of additive-free ZrC ceramics prepared by spark plasma sintering, Materials, 9 (6) (2016), 489
• D.M. Trucchi, A. Bellucci, M. Girolami, P. Calvani, E. Cappelli, S. Orlando, R. Polini, L. Silvestroni, D. Sciti, A. Kribus, “Solar Thermionic-Thermoelectric Generator (ST2G): concept, material engineering, and prototype demonstration”, Advanced Energy Materials (2018) 1802310.
• R. Licheri, C. Musa, A.M. Locci, S. Montinaro, R. Orrù1, G. Cao, L. Silvestroni, D. Sciti, N. Azzali, L. Mercatelli, E. Sani, “Ultra-High temperature Porous Graded Ceramics for Solar Energy Applications”, Journal of the European Ceramic Society, 39 [1] 72-78 (2019).
• L. Silvestroni, D. Sciti, A. Balbo, R. Licheri, C. Musa, R. Orrù, G. Cao, L. Mercatelli, N. Azzali, E. Sani, “An overview of ultra-refractory ceramic absorbers for thermodynamic solar energy generation at high temperature”, Renewable Energy 133 (2019) 1257-1267.