Articles publicats en revistes (Ciència dels Materials i Química Física)

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Cosmic-ray acceleration and escape from supernova remnant W44 as probed by Fermi-LAT and MAGIC
(EDP Sciences, 2025-01-23) Abe, S.; Abhir, J.; Abhishek, A.; Acciari, V. A.; Aguasca Cabot, Arnau; Agudo, I.; Aniello, T.; Ansoldi, S.; Antonelli, L. A.; Arbet-Engels, Axel; Arcaro, C.; Asano, K.; Babić, A.; Baquero, A.; Barres de Almeida, U.; Barrio, J. A.; Batković, I.; Bautista, A.; Baxter, J.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Bernete, J.; Berti, A.; Besenrieder, J.; Bigongiari, C.; Biland, A.; Blanch, O.; Bonnoli, G.; Bošnjak, Ž.; Bronzini, E.; Burelli, I.; Busetto, G.; Campoy-Ordaz, A.; Carosi, A.; Carosi, R.; Carretero-Castrillo, Mar; Castro-Tirado, A.J.; Cerasole, D.; Ceribella, G.; Chai, Yandong; Chilingarian, A.; Cifuentes, A.; Colombo, E.; Contreras, J.L.; Cortina, J.; Covino, S.; D'Amico, G.; D'Elia, V.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Menezes, R.; Del Popolo, A.; Delfino, M.; Delgado, Jordi; Delgado Mendez, C.; Di Pierro, F.; Dominis Prester, D.; Donini, A.; Dorner, D.; Doro, M.; Elsaesser, D.; Emery, G.; Escudero, J.; Fariña, L.; Fattorini, A.; Foffano, L.; Font, L.; Fröse, S.; Fukazawa, Y.; García López, R.J.; Garczarczyk, M.; Gasparyan, S.; Gaug, M.; Giesbrecht Paiva, J.G.; Giglietto, N.; Gliwny, P.; Godinović, N.; Gozzini, Sara Rebecca; Gradetzke, T.; Grau, R.; Green, J.G.; Günther, P.; Hadasch, D.; Hahn, A.; Hassan, T.; Heckmann, L.; Herrera, J.; Hrupec, D.; Hütten, M.; Imazawa, R.; Ishio, K.; Jiménez Martínez, I.; Jormanainen, J.; Kayanoki, T.; Kerszberg, D.; Kluge, G.W.; Kobayashi, Y.; Kouch, P.M.; Kubo, H.; Kushida, J.; Láinez, M.; Lamastra, A.; Leone, F.; Lindfors, E.; Linhoff, L.; Lombardi, S.; Longo, F.; López-Coto, R.; López-Moya, M.; López-Oramas, A.; Loporchio, S.; Lorini, A.; Lyard, E.; Machado de Oliveira Fraga, B.; Majumdar, P.; Makariev, M.; Maneva, G.; Mang, N.; Manganaro, M.; Mangano, S.; Mannheim, K.; Mariotti, M.; Martínez, Manel; Martínez-Chicharro, M.; Mas-Aguilar, A.; Mazin, D.; Menchiari, S.; Mender, S.; Miceli, D.; Miener, T.; Miranda, J.M.; Mirzoyan, R.; Molero González, M.; Molina, Edgar; Mondal, H.A.; Moralejo, A.; Morcuende, D.; Nakamori, T.; Nanci, C.; Nava, L.; Neustroev, V.; Nickel, L.; Nievas Rosillo, M.; Nigro, C.; Nikolić, L.; Nishijima, K.; Njoh Ekoume, T.; Noda, K.; Nozaki, S.; Ohtani, Y.; Okumura, A.; Otero-Santos, J.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, Riccardo; Paredes i Poy, Josep Maria; Peresano, M.; Persic, M.; Pihet, Marine; Pirola, G.; Podobnik, F.; Prada Moroni, P.G.; Prandini, E.; Principe, G.; Priyadarshi, C.; Rhode, W.; Ribó Gomis, Marc; Rico, J.; Righi, C.; Sahakyan, N.; Saito, T.; Satalecka, K.; Saturni, F.G.; Schleicher, B.; Schmidt, K.; Schmuckermaier, F.; Schubert, J.L.; Schweizer, T.; Sciaccaluga, A.; Silvestri, G.; Sitarek, J.; Sliusar, V.; Sobczynska, D.; Spolon, A.; Stamerra, A.; Strišković, J.; Strom, D.; Strzys, M.; Suda, Y.; Suutarinen, S.; Tajima, H.; Takahashi, M.; Takeishi, R.; Temnikov, P.; Terauchi, K.; Terzić, T.; Teshima, M.; Truzzi, S.; Tutone, A.; Ubach, S.; van Scherpenberg, J.; Vazquez Acosta, M.; Ventura, Salvador; Viale, I.; Vigorito, C.F.; Vitale, V.; Vovk, I.; Walter, Rudolf; Will, M.; Wunderlich, Carolin; Yamamoto, T.; Di Tria, R.; Di Venere, L.; Giordano, F.; Bissaldi, E.; Green, D.; Morlino, G.
Context. The supernova remnant (SNR) W44 and its surroundings are a prime target for studying the acceleration of cosmic rays (CRs). Several previous studies established an extended gamma-ray emission that is set apart from the radio shell of W44. This emission is thought to originate from escaped high-energy CRs that interact with a surrounding dense molecular cloud complex. Aims. We present a detailed analysis of Fermi-LAT data with an emphasis on the spatial and spectral properties of W44 and its surroundings. We also report the results of the observations performed with the MAGIC telescopes of the northwestern region of W44. Finally, we present an interpretation model to explain the gamma-ray emission of the SNR and its surroundings. Methods. We first performed a detailed spatial analysis of 12 years of Fermi-LAT data at energies above 1 GeV, in order to exploit the better angular resolution, while we set a threshold of 100 MeV for the spectral analysis. We performed a likelihood analysis of 174 hours of MAGIC data above 130 GeV using the spatial information obtained with Fermi-LAT. Results. The combined spectra of Fermi-LAT and MAGIC, extending from 100 MeV to several TeV, were used to derive constraints on the escape of CRs. Using a time-dependent model to describe the particle acceleration and escape from the SNR, we show that the maximum energy of the accelerated particles has to be ≃40 GeV. However, our gamma-ray data suggest that a small number of lower-energy particles also needs to escape. We propose a novel model, the broken-shock scenario, to account for this effect and explain the gamma-ray emission.
Optimization of Fe3Al intermetallic cold gas spray coatings: Microstructural characterization
(Elsevier B.V., 2025-03-11) Dosta Parras, Sergi; Clave, Genís; Betancor, Lorena; Barreneche, Camila; Martín-Vilardell, Anna
Cold Gas Spray (CGS) is increasingly applied in industry and becoming even more important in advanced applications. This study focuses on the use of CGS process optimization of metal transitional aluminides, specifically Fe3Al. These low-cost materials have high resistance to sulfidation and carburizing atmospheres, as well as excellent oxidation resistance at high temperatures. Therefore, this study aims to deposit Fe3Al powders via CGS onto steel substrates, evaluating the use of Helium (He) and Nitrogen (N2) as carrier gases, examining the influence of particle size distribution of two powders. The coatings have been optimized by studying the splat formation and their microstructures to better understand the deposition process. The best coatings have been characterized by microstructural analysis with scanning electron microscopy and energy dispersive X-ray spectroscopy, also measuring their microhardness. The work concludes that Fe3Al coatings have been successfully deposited by CGS. Therefore, dense coatings were achieved by using both He and N2 as carrier gases for the fine powder. Even so, the use of He as the carrier gas produces thicker and harder coatings, as particles reached higher velocities, allowing also to produce a good coating with the coarse powder.
Identifying the Atomic Layer Stacking of Mo2C MXene by Probe Molecule Adsorption
(American Chemical Society, 2021-12-09) Jurado, Anna; Morales García, Ángel; Viñes Solana, Francesc; Illas i Riera, Francesc
A density functional theory study is presented here aimed at investigating whether the atomic stacking on the new family of two-dimensional MXene materials has an influence on their adsorption properties and whether these properties can provide information about this structural feature. To this end, the Mo2C MXene, exhibiting two nearly degenerate crystal structures with either ABC or ABA atomic stacking, is chosen as a case study. The study of the adsorption of CO, CO2, and H2O on both polymorphs of Mo2C reveals substantial differences that could be used in experiments to provide information about the atomic stacking of a given sample. Particularly, we show that the asymmetric and symmetric stretching modes of the adsorbed CO2 and the CO stretching mode are clear features that allow one to identify the stacking of atomic layers of the Mo2C MXene. The present finding is likely to apply to other MXenes as well.
Finding Key Factors for Efficient Water and Methanol Activation at Metals, Oxides, MXenes, and Metal/Oxide Interfaces
(American Chemical Society, 2022-01-21) Su, Hai-Yan; Sun, Keju; Gu, Xiang-Kui; Wang, Sha Sha; Zhu, Jing; Li, Wei-Xue; Sun, Chenghua; Calle Vallejo, Federico
Activating water and methanol is crucial in numerous catalytic, electrocatalytic, and photocatalytic reactions. Despite extensive research, the optimal active sites for water/methanol activation are yet to be unequivocally elucidated. Here, we combine transition-state searches and electronic charge analyses on various structurally different materials to identify two features of favorable O–H bond cleavage in H2O, CH3OH, and hydroxyl: (1) low barriers appear when the charge of H moieties remains approximately constant during the dissociation process, as observed on metal oxides, MXenes, and metal/oxide interfaces. Such favorable kinetics is closely related to adsorbate/substrate hydrogen bonding and is enhanced by nearly linear O–H–O angles and short O–H distances. (2) Fast dissociation is observed when the rotation of O–H bonds is facile, which is favored by weak adsorbate binding and effective orbital overlap. Interestingly, we find that the two features are energetically proportional. Finally, we find conspicuous differences between H2O/CH3OH and OH activation, which hints toward the use of carefully engineered interfaces.
Insights of a Novel HEA Database Created from a Materials Perspective, Focusing on Wear and Corrosion Applications
(MDPI, 2025-07-23) Betancor, Lorena; Clave, Genís; Barreneche, Camila; Dosta Parras, Sergi
In recent years, interest in HEAs has increased exponentially due to their extraordinary properties, especially for wear- and corrosion-resistant applications. However, the main problem involves correctly selecting the HEA composition required for a specific application, as most of the data are scattered throughout the literature, and only a limited number of models accurately predict the properties. Therefore, a database of 415 HEA alloys (bulk) and coatings obtained using thermal spray (TS) techniques has been created, compiled from scientific studies over the past 20 years. This tool collects information on physical, mechanical, and chemical properties, with a particular emphasis on corrosion and wear resistance. This facilitates material comparison and selection according to the needs of a specific application. In particular, the database highlights how composition and deposition technique also affect performance, identifying CoCrFeNi (CGS and in bulk) as a promising candidate for simultaneous wear and corrosion resistance.
In-depth study of the dry-anodizing process on Ti6Al4V alloys: Effect of the acid content and electrical parameters
(Elsevier B.V., 2025-01-10) Valencia Cadena, Andrea; García Blanco, M. Belen; Reschenhofer, Bernhard; Barreneche, Camila; Skerbis, P.; Leitl, P.A.; Santamaría Cabodevilla, Pablo; Roa Rovira, Joan Josep
Titanium (Ti) surface has the capability of changing color due to the oxides formed when it meets oxygen under acidic solutions and current application. Additionally, this passive oxide film formed on the Ti surface is responsible for its high corrosion resistance that is needed in several industries. Consequently, titanium has a wide range of applications in the aerospace, automotive, and biomedical industries. This study introduces a never-used dry-anodizing process utilizing DryLyte® Technology. In this sense, the effects of electrical parameters (voltage, and current density) and the acid content of the dry electrolyte on the performance of the new dry-anodizing process are evaluated using different advanced characterization techniques. Direct and indirect coating thickness measurement of the anodic layer by using the Focused Ion Beam and reflectometric techniques, respectively, revealed that the anodic layer thickness does not depend on the acid content, yielding a homogeneous value of around 60 nm. Additionally, the study demonstrated that the application of low-frequency pulses with a duty cycle of 20 %, reduce the heating during the process and allows to increase further the anodizing voltage compared with direct current anodizing, thereby expanding the available color range. Finally, the experimental results were adjusted to a polynomial fitting to predict the TiO2 anodizing layer thickness induced along the process. From all the aforementioned information, it has been stablished that the anodizing quality of the dry electrolyte decreases under service-like working conditions, which is mainly attributed to two different effects related to the electrical current that passes through the polymeric particles and that takes place at the same time: (1) dehydration of the particle and (2) degradation of the core-shell structure, caused by Joule's effect during the dry-anodizing process.
Hybridization of Salt Hydrates with Solid–Solid Phase Change Materials: A Novel Pathway to Sorption Thermochemical Materials Manufacturing
(Wiley-VCH, 2023-05-13) Palacios, A.; Navarro, M.E.; Barreneche, Camila; Ding, Y.
Major advancements are needed in the thermochemical energy storage (TCES) field to bring the technology to commercial levels. The current research strategies are focused on improving heat and mass transfer using different supporting materials to achieve mechanical integrity during storage. However, these strategies are still under development, and they have not overcome the lab scale yet. This work explores novel matrices to expand the material database for TCES composites. Pure structural matrices (cellulose) and novel matrices with storage potential (polymeric solid–solid phase change materials) are selected and combined with three well-known thermochemical materials (TCMs) (MgSO4·6H2O, SrBr2·6H2O and MgCl2·6H2O), providing evidence of hybridized composites with storage capacity up to 2.4 GJ m−3 with a 25–20 wt% of polymeric matrix. The polymer content is found to act as a nucleating agent in the magnesium sulfate crystallization process forming a synthetic monohydrate crystalline phase (Kieserite) and inhibiting the formation of the amorphous phase. The effect of the matrix is proved to induce certain structural deformation or changes not observed in the pure TCM sorption process. This phenomenon has the potential to benefit the stabilization of the TCM, e.g., inhibition of the formation of amorphous phase in magnesium sulfate composites.
Performance analysis of a novel multi-module columnar packed bed reactor with salt hydrates for thermochemical heat storage
(Elsevier, 2024-05-01) Hao, C.; Feng, G.; Ma, C.; Barreneche, Camila; She, X.
The thermochemical heat storage based on salt hydrate has great advantages of high energy storage density and applicability to seasonal heat storage. In conventional packed-bed reactors, salt hydrates are often simply accumulated, and the air diffuses inside the pores. As a result, the salt hydrates are prone to agglomeration during the reaction, which will reduce the performance. To address these issues, this paper designs a multi-module columnar packed-bed reactor. The performance of top peripheral air intake and bottom central air intake schemes is numerically compared, and the effects of working parameters, structural parameters and physical parameters are analyzed. The results show that the bottom central air intake scheme has obvious advantages of uniform reaction rate, short reaction time and small resistance loss compared with the top peripheral air intake scheme. It is found that the reaction time is shortened by 46.6 % and the heat storage efficiency increases from 80.4 % to 83.8 % when the inlet air temperature increases from 75 to 95 °C. Besides, the reaction time decreases by 20.7 % as the inlet air velocity increased from 1 to 3 m/s and the optimal spacing of the hydrated salt modules is 0.3 cm. These results are promoting the development of thermochemical heat storage.
Protective Laser Cladding Coatings for Thermal Energy Storage Tanks in contact with Molten Salt-Based Nanofluids
(Elsevier, 2026-04-06) Betancor, Lorena; Svobodova Sedlackova, Adela; Clave, Genís; Barreneche, Camila; Dosta Parras, Sergi
Intermittency of renewable energy sources is a critical problem. Concentrated Solar Power (CSP) power plants with thermal storage systems offer one of the main solutions. Among the many storage processes, nanofluids are a method of improving thermal performance but inducing corrosion of storage units. This study investigates the potential of Inconel-625 and Stellite-6 coatings deposited by laser cladding in preventing nanofluid-induced corrosion in CSP thermal storage units. AISI 316L stainless steel samples coated with Stellite-6 and Inconel-625 were tested for corrosion in NaNO3 containing SiO2 nanoparticles at 450 °C for 30, 60, and 90 days. Cross-section analysis was used to assess thickness loss, and coatings were analysed. Chemical attack enhanced material contrast for microstructural observation. Compositions of oxides were identified by EDS and XRD analysis, and ICP analysis identified elements in the salts after corrosion. Results showed almost no loss in thickness, even after 90 days, to substantiate the protective efficacy of coatings. Results confirm that Inconel-625 and Stellite-6 coatings are a reliable source of preventing corrosion caused by nanofluids in CSP thermal storage systems.
Experimental evaluation of carbon-coated sand as solar-absorbing and thermal energy storage media for concentrated solar power applications
(Elsevier, 2025-06-15) Rodríguez, J.B.; Majó, M.; Mondragón, Rosa; Barreneche, Camila; Díaz-Heras, M.; Canales-Vázquez, J.; Almendros-Ibáñez, J.A.; López Hernández, Leonor
Innovative systems using solid particles for solar energy capture, heat transfer, and thermal energy storage are emerging in next-generation concentrating solar power plants. This study investigates silica sand enhancement using novel coatings of graphite, carbon black, and glucose, evaluating their thermal stability, optical properties and durability under operational conditions. The coated samples were subjected to fluidisation and radiation treatments to simulate real-world conditions. Thermogravimetric analysis, specific heat capacity measurements, optical absorptance evaluation, and photothermal conversion efficiency testing were performed. The results show that graphite-coated sand exhibits superior optical and thermal performance, achieving a 44.9 % increase in photothermal conversion efficiency compared to uncoated sand. While carbon black coatings displayed higher absorptance, their heterogeneity compromised long-term effectiveness. Glucose coatings degraded above 280 °C, rendering them unsuitable. An industrial-scale fluidised bed model was used to assess the impact of the observed enhanced particle absorptance on the resulting performance of these systems, revealing thermal efficiency improvements of 50 %. These findings confirm that graphite-coated sand is a viable solution for high-temperature concentrating solar power plants applications, offering stable performance, enhanced light-to-heat conversion and improved energy efficiency in large-scale
Exploring the potential of a potash by-product for thermochemicalheat storage
(Elsevier, 2026-02-25) Mamani Challapa, Verónica Lisbeth; Gutiérrez, Andrea; Fernández Renna, Ana Inés; Ushak, Svetlana N.
Thermochemical energy storage is an effective method for seasonal heat storage applications, as it stores energy on a long-term basis. This process captures excess heat generated during the summer, whether from solar energy or surplus heat from supply chains, and utilizes it during the winter months. However, the process relies on chemical reactions, which pose various technical challenges. Additionally, it requires a significant amount of materials, leading to increased system costs. In this study, we propose to investigate potassium carnallite as a low-cost thermochemical material (TCM). This material is derived from potash saline deposits located in northeastern Spain. Characterization through chemical analysis revealed that it comprises 86.0% KCl·MgCl2·6 H2O, with NaCl as the main impurity at a concentration of 10%. The dehydration and hydration reactions analyzed involve the loss and retention of 4 molecules of H2O. Importantly, there is no evidence that the hydrolysis decomposition of the material affects the reversibility of these reactions. The study demonstrated a good reversibility of the reaction, with a yield of 81.73%, which decreased to 78.83% by the tenth cycle. These cycles simulate 10 years of seasonal use under specific conditions (PHy = 1.3 kPa, THy = 40 °C, PDe = 4.0 kPa, and TDe = 110 °C). Notably, natural carnallite exhibited 20% higher reversibility compared to synthetic carnallite. However, it was found to be 14% less reversible during the first cycle and 8.4% less reversible by the tenth cycle compared to another carnallite material studied under the same conditions previously. This difference in reversibility may be attributed to variations in the impurity content of both materials, where a higher concentration of NaCl in carnallite may act as a chemical spacing, facilitating water vapor mass transfer and consequently improving cycling stability. We measured an energy density of 0.892 GJ/m3 during the tenth hydration cycle, indicating that the winter energy needs of a household can be met using 9.0 m3 of thermochemical material. These findings suggest that by-products from mining, such as carnallite, are promising candidates for seasonal heat storage applications. However, improvements in the material are needed to increase the energy density at large scale, which would consequently reduce the volume of material required for the application using a reactor system.
Protective thermal spray coatings for TES applications in CSP plants
(Elsevier B.V., 2025-06-03) Betancor, Lorena; Svobodova Sedlackova, Adela; Clave, Genís; Barreneche, Camila; Dosta Parras, Sergi
Corrosion caused by using molten salts in thermal storage systems in Concentrated Solar Power (CSP) plants is a major problem in this field. To eliminate this problem, the use of nanofluids and the application of Inconel-625 coatings by thermal spray techniques (High Velocity Oxygen Fuel - HVOF and Cold Gas Spray - CGS) are proposed. This study focuses on evaluating the effectiveness of these coatings, deposited on AISI 316 stainless in mitigating nanofluid-induced corrosion in CSP plant Thermal Energy Storage (TES) systems. For this purpose, a total immersion test in NaNO<sub>3</sub> with silica nanoparticles was carried out in a furnace at 450 °C under air atmosphere for 30 days (720 h) and 90 days (2160 h). The test was also performed on SS316L and Inconel-625 bulk substrate samples for better comparison. Evaluation of corrosion behaviour relied on measuring the reduction in cross-sectional thickness of the test samples. Furthermore, detailed characterization was performed using Laser Scattering (LS), Scanning Electron Microscopy (SEM), and Field Emission Scanning Electron Microscopy (FESEM). The coating surface was also studied by X-Ray Diffraction (XRD), and the molten salt-based nanofluids were studied by Inductively Coupled Plasma (ICP). The results obtained revealed notably minimal corrosion rates per year for both deposition methods, after 3 months of testing. This demonstrates the effectiveness of both HVOF and CGS Inconel-625 coatings as a reliable solution to decrease the level of corrosion in TES units. However, future studies should be conducted over longer periods and with operating conditions closely replicating working conditions.
Understanding failure in austenitic steels: Key considerations for moltensalt storage in CSP applications
(Elsevier, 2026-02-26) Ardila Parra, Sergio Andrés; Prieto Ríos, Cristina; Osorio, Julian D.; Fernández Renna, Ana Inés
Owing to their excellent properties, austenitic stainless steels are extensively used in boilers, furnaces, molten salt tanks, and other applications that are subjected to extreme mechanical loads and high-temperature conditions. Their high corrosion and creep resistance make them suitable for high-temperature operating environments.Additionally, good fatigue resistance and favorable mechanical and visual properties are essential. However, the premature failure of several components at elevated temperatures has been previously reported. Although the failure analysis of components in service is complex, processes such as cold work and welding have been identified as contributing factors to the performance degradation of these steels. This study aims to analyze the various documented failure modes and mechanisms in austenitic steels, including creep, cracking, stress relaxation cracking, and fatigue, to better understand the multi-objective design requirements for these alloys as structural materials for high-temperature molten salt tanks in Concentrating Solar Power (CSP) plants. Stabilized austenitic grades, such as AISI 347H, demonstrate superior resistance to creep and corrosion-related degradation when compared to non-stabilized grades like AISI 316L at temperatures relevant to concentrated solar power (CSP) applications. In contrast, nickel-based alloys offer enhanced corrosion resistance, albeit at a higher cost. This review underscores that creep, stress relaxation cracking, and thermo-mechanical fatigue are the predominant long-term failure risks in CSP hot tanks.
Experimental validation of thermochemical water-sorption materials for thermal energy storage: Building application
(Elsevier, 2023-12-01) Palacios, A.; Navarro, M.E.; Barreneche, Camila; Ding, Y.
Salt hydrates for seasonal heat storage have emerged as an important research topic due to their potential to fulfil the heat demand in the residential and commercial building sector. However, the research undertaken has not yet covered key aspects of their fundamental thermal behaviour understanding e.g. experimentally validation, characterisation methodologies or material screening. The present investigation is aimed to identify promising thermochemical materials in the temperature range of 25–150 C, which are suitable for building applications and waste heat recovery. A list of ten salt hydrates has been screened through an experimental validation, which was developed and optimized for the specific working conditions. The salt hydrates were tested under operational conditions and key properties are assessed (thermal conductivity, specific heat, volume change, etc). Different case studies were used to narrow down to a list of final salts candidates under three theoretical working conditions scenarios for both open and closed systems. The cases of study prioritised high energy density (after one hydration/dehydration cycle), acceptable volume expansion and stability, which led to the final candidates. Magnesium sulphate was selected in the case of high energy density (>2 MJ/m3) and low cost (1 €/MJ), when lowering the energy density to 1 MJ/m3 calcium sulphate and copper sulphate were revealed as promising candidates for open and closed systems. While calcium nitrate was identified as a candidate along with magnesium sulphate when considering closed systems.
Life cycle assessment of a conventional thermal energy storage system versus an alternative steel slag-based system for concentrating solar power plants
(Elsevier, 2026-02-01) Vielma Leal, Carlos A.; Majó, M.; Calderon Diaz, Alejandro; Svobodova Sedlackova, Adela; Fernández Renna, Ana Inés; Barreneche, Camila
Thermal Energy Storage (TES) plays a crucial role in advancing decarbonisation. Its integration into Concentrated Solar Power (CSP) plants can significantly enhance efficiency and support renewable power generation. The primary commercial TES material, Solar Salt (SS), presents technical challenges and has the highest environmental impact in TES systems. An innovative alternative is Electric Arc Furnace Steel Slag (EAFSS), a steel industry by-product that can be repurposed as TES material. However, the environmental sustainability of EAFSS for TES applications has not been comprehensively studied. This research quantified the environmental impact of a thermocline TES system using EAFSS as a filler material, compared with a conventional SS system. A Life Cycle Assessment, employing mass and economic allocation methods, examined EAFSS environmental burdens across two SS reduction scenarios. A sensitivity analysis of EAFSS costs showed savings exceeding 30 % compared to SS. At the CSP plant level, the ReCiPe method indicated impact reductions of 9–10 % using mass allocation and 22–26 % with economic allocation. Global warming emissions were higher with mass allocation (0.400–0.408 kg CO2eq/kWh) than with the conventional TES system (0.358 kg CO2eq/kWh), which may benefit steelmaking industries by attributing a larger share of their emissions to CSP systems. In contrast, economic allocation yielded lower emissions (0.330–0.325 kg CO2eq/kWh), providing more credit to EAFSS for its valorisation. These findings underscore the potential of EAFSS to enhance CSP sustainability while valorising waste/by-products to generate greener electricity.
Methodology for the Prediction of the Thermal Conductivity of Concrete by Using Neural Networks
(MDPI, 2024-08-28) Rosa, Ana Carolina; Elomari, Youssef; Calderon Diaz, Alejandro; Mateu, Carles; Haddad, Assed; Boer, Dieter
The energy consumption of buildings presents a significant concern, which has led to a demand for materials with better thermal performance. Thermal conductivity (TC), among the most relevant thermal properties, is essential to address this demand. This study introduces a methodology integrating a Multilayer Perceptron (MLP) and a Generative Adversarial Network (GAN) to predict the TC of concrete based on its mass composition and density. Three scenarios using experimental data from published papers and synthetic data are compared and reveal the model’s outstanding performance across training, validation, and test datasets. Notably, the MLP trained on the GAN-augmented dataset outperforms the one with the real dataset, demonstrating remarkable consistency between the model’s predictions and the actual values. Achieving an RMSE of 0.0244 and an R2 of 0.9975, these outcomes can offer precise quantitative information and advance energy-efficient materials.
Thermodynamic modelling of a thermal energy storage packed bed tank: Exploring the influence of different particle sizes on overall performance
(Elsevier, 2025-05-30) Liu, Xianglei; Luo, Qingyang; Majó, M.; Calderon Diaz, Alejandro; Barreneche, Camila; Li, Jiawei; Tian, Yang; Fernández Renna, Ana Inés
Concentrated solar power combined with thermal energy storage (TES) technology is now widely employed in power generation. To enhance heat transfer efficiency during thermal charging and discharging processes, a packed bed TES system has been developed due to its high heat transfer rate and large heat transfer area. To unveil the overall performance of the packed bed, thermodynamic models are introduced to avoid problems like large size and complex structure. However, current developed models are too vague to study the size effect and pressure drop induced by the particle diameter. In this work, a two-solid-phase model is introduced to evaluate the size effect in packed bed TES systems during charging and discharging, utilizing molten salt and natural volcanic ash as the heat transfer fluid and main solid filler, respectively. Compared to single-phase packed bed, introducing small particles to occupy the void between the large particles yields a low void fraction, and thus the energy storage density is improved by 36.4 %. In the meantime, the thermal charging efficiency is enhanced from 54.37 % to 75.64 %. However, the pressure drop is inevitably increased because of the very low void fraction and the increased surface in contact with the fluid. The pressure drop follows an exponential trend with the changes in particle size. Furthermore, the thermocline in the packed bed requires careful consideration, as it corresponds to the location where the maximum pressure gradient occurs. This work provides insights into the effects of the packed bed induced by the particle size, offering valuable information for the design of next-generation TES packed beds.
Long-Term Compatibility Testing of Solar Salt and Solid Particles at High Temperatures: A Thermal and Chemical Characterization
(John Wiley & Sons, 2025-02-26) Majó, M.; Svobodova Sedlackova, Adela; Barcelona Pons, Pol; Fernández Renna, Ana Inés; Calderon Diaz, Alejandro; Barreneche, Camila
Thermal energy storage offers a viable solution to address the global energy problem of balancing the gap between the energy demand and the energy supply. One of the most advanced and mature thermal energy storage technologies in solar power technologies is a Concentrating Solar Power plant with a tower configuration and molten salts as thermal energy storage. Despite their advantages, molten salts also have limitations that include their corrosive nature, solidification at temperatures below 240°C, and high cost. Therefore, alternative thermal energy storage materials, such as solid-state thermal storage using concrete blocks or ceramic particles, are under research. Solid particles have a high thermal energy storage density, comparable to molten salts, and can withstand higher temperatures, making them well-suited for use in Concentrating Solar Power systems. The use of alternative materials for thermal energy storage is an important aspect of the circular economy concept, which aims to extract the maximum value from resources and reduce greenhouse gas emissions. This work aims to test the compatibility of Solar Salt with several alternative materials for use as thermal energy storage media, including silica sand, commercially sintered bauxite, and two different waste materials from the mining and steel industries. The study compares the thermal and chemical properties of these solid-molten salt mixtures with those of Solar Salt and quantifies the formation of nitrites in Solar Salt as a direct measurement of Solar Salt degradation. Additionally, a rheology study was conducted on the Solar Salt samples, revealing slight changes in viscosity attributed to the nitrite content. Although the thermal properties of the materials remained almost identical and natural and inert ceramic materials exhibited good compatibility, Solar Salt in contact with the waste materials exhibited the formation of nitrites, indicating an expected further degradation of the Solar Salt within these compounds.
Thermal cycling test of solar salt in contact with sustainable solid particles for concentrating solar power (CSP) plants
(MDPI, 2024-05-01) Majó, M.; Svobodova Sedlackova, Adela; Fernández Renna, Ana Inés; Calderon Diaz, Alejandro; Barreneche, Camila
Thermal energy storage (TES) is crucial in bridging the gap between energy demand and supply globally. Concentrated Solar Power (CSP) plants, employing molten salts for thermal storage, stand as an advanced TES technology. However, molten salts have drawbacks like corrosion, solidification at lower temperatures, and high costs. To overcome these limitations, research is focusing on alternative TES materials such as ceramic particles. These solids match molten salts in energy density and can withstand higher temperatures, making them well-suited for CSP systems. This study revolves around subjecting Solar Salt alone and Solar Salt alongside Volcanic Ash (VA) and Electric Arc Furnace Slag (EAFS) to a comprehensive thermal cycling test. This test is designed to assess the compatibility over the thermal cycles of the Solar Salt and the Solar Salt in contact with these solids in a CSP plant with a thermocline configuration. With a final thermal and chemical evaluation, our observations indicate that EAFS and VA demonstrate promising compatibility but an increase in the reduction rate of the Solar Salt due to a catalyst effect from EAFS in contact with the salt. No discernible alterations were detected in the properties of either the solid materials or solar salt when combined.
Mechanical-physical methods for paint removal of recycled bumpers for revalorization in the automotive industry
(Elsevier, 2024-11-05) Zambrano Membrives, Carla; Fernández Renna, Ana Inés; Tamarit, Pablo; Barreneche, Camila
The automotive industry uses plastics in the manufacture of car components due to their benefits such as weight reduction, high friction resistance, energy absorption, and versatility in blending with other materials and in its processability. A wide variety of plastic are used in vehicles. Although up to 13 different types of polymers may be used in a single car model, the most common is Polypropylene (PP). Nowadays, mechanical recycling is the most common method for recycling plastic waste from end-of-life vehicles in the automotive industry. However, challenges arise from material heterogeneity, presence of paint or impurities which affect mechanical properties and quality of recycled materials. Various chemical and physical methods to remove these impurities but economic, technical and feasibility considerations influence the adoption of technology in the industry. The current paper focuses on mechanical-physical procedures for paint removal from recycled automotive thermoplastics, aiming to maintain the properties of the polymer matrix and overcome environmental, economic and complex barriers. The used methods have shown success in removing paint from PP surfaces, with the pressing machine method with the best efficiency at a 38 % reduction. Despite not achieving over 90 % paint removal, these procedures establish fundamental principles for effective industrial mechanical paint depainting.

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