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Search Results (127)

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Keywords = radiative and thermal conductivity

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21 pages, 2049 KiB  
Article
Tracking Lava Flow Cooling from Space: Implications for Erupted Volume Estimation and Cooling Mechanisms
by Simone Aveni, Gaetana Ganci, Andrew J. L. Harris and Diego Coppola
Remote Sens. 2025, 17(15), 2543; https://doi.org/10.3390/rs17152543 - 22 Jul 2025
Viewed by 1003
Abstract
Accurate estimation of erupted lava volumes is essential for understanding volcanic processes, interpreting eruptive cycles, and assessing volcanic hazards. Traditional methods based on Mid-Infrared (MIR) satellite imagery require clear-sky conditions during eruptions and are prone to sensor saturation, limiting data availability. Here, we [...] Read more.
Accurate estimation of erupted lava volumes is essential for understanding volcanic processes, interpreting eruptive cycles, and assessing volcanic hazards. Traditional methods based on Mid-Infrared (MIR) satellite imagery require clear-sky conditions during eruptions and are prone to sensor saturation, limiting data availability. Here, we present an alternative approach based on the post-eruptive Thermal InfraRed (TIR) signal, using the recently proposed VRPTIR method to quantify radiative energy loss during lava flow cooling. We identify thermally anomalous pixels in VIIRS I5 scenes (11.45 µm, 375 m resolution) using the TIRVolcH algorithm, this allowing the detection of subtle thermal anomalies throughout the cooling phase, and retrieve lava flow area by fitting theoretical cooling curves to observed VRPTIR time series. Collating a dataset of 191 mafic eruptions that occurred between 2010 and 2025 at (i) Etna and Stromboli (Italy); (ii) Piton de la Fournaise (France); (iii) Bárðarbunga, Fagradalsfjall, and Sundhnúkagígar (Iceland); (iv) Kīlauea and Mauna Loa (United States); (v) Wolf, Fernandina, and Sierra Negra (Ecuador); (vi) Nyamuragira and Nyiragongo (DRC); (vii) Fogo (Cape Verde); and (viii) La Palma (Spain), we derive a new power-law equation describing mafic lava flow thickening as a function of time across five orders of magnitude (from 0.02 Mm3 to 5.5 km3). Finally, from knowledge of areas and episode durations, we estimate erupted volumes. The method is validated against 68 eruptions with known volumes, yielding high agreement (R2 = 0.947; ρ = 0.96; MAPE = 28.60%), a negligible bias (MPE = −0.85%), and uncertainties within ±50%. Application to the February-March 2025 Etna eruption further corroborates the robustness of our workflow, from which we estimate a bulk erupted volume of 4.23 ± 2.12 × 106 m3, in close agreement with preliminary estimates from independent data. Beyond volume estimation, we show that VRPTIR cooling curves follow a consistent decay pattern that aligns with established theoretical thermal models, indicating a stable conductive regime during the cooling stage. This scale-invariant pattern suggests that crustal insulation and heat transfer across a solidifying boundary govern the thermal evolution of cooling basaltic flows. Full article
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35 pages, 2895 KiB  
Review
Ventilated Facades for Low-Carbon Buildings: A Review
by Pinar Mert Cuce and Erdem Cuce
Processes 2025, 13(7), 2275; https://doi.org/10.3390/pr13072275 - 17 Jul 2025
Viewed by 601
Abstract
The construction sector presently consumes about 40% of global energy and generates 36% of CO2 emissions, making facade retrofits a priority for decarbonising buildings. This review clarifies how ventilated facades (VFs), wall assemblies that interpose a ventilated air cavity between outer cladding [...] Read more.
The construction sector presently consumes about 40% of global energy and generates 36% of CO2 emissions, making facade retrofits a priority for decarbonising buildings. This review clarifies how ventilated facades (VFs), wall assemblies that interpose a ventilated air cavity between outer cladding and the insulated structure, address that challenge. First, the paper categorises VFs by structural configuration, ventilation strategy and functional control into four principal families: double-skin, rainscreen, hybrid/adaptive and active–passive systems, with further extensions such as BIPV, PCM and green-wall integrations that couple energy generation or storage with envelope performance. Heat-transfer analysis shows that the cavity interrupts conductive paths, promotes buoyancy- or wind-driven convection, and curtails radiative exchange. Key design parameters, including cavity depth, vent-area ratio, airflow velocity and surface emissivity, govern this balance, while hybrid ventilation offers the most excellent peak-load mitigation with modest energy input. A synthesis of simulation and field studies indicates that properly detailed VFs reduce envelope cooling loads by 20–55% across diverse climates and cut winter heating demand by 10–20% when vents are seasonally managed or coupled with heat-recovery devices. These thermal benefits translate into steadier interior surface temperatures, lower radiant asymmetry and fewer drafts, thereby expanding the hours occupants remain within comfort bands without mechanical conditioning. Climate-responsive guidance emerges in tropical and arid regions, favouring highly ventilated, low-absorptance cladding; temperate and continental zones gain from adaptive vents, movable insulation or PCM layers; multi-skin adaptive facades promise balanced year-round savings by re-configuring in real time. Overall, the review demonstrates that VFs constitute a versatile, passive-plus platform for low-carbon buildings, simultaneously enhancing energy efficiency, durability and indoor comfort. Future advances in smart controls, bio-based materials and integrated energy-recovery systems are poised to unlock further performance gains and accelerate the sector’s transition to net-zero. Emerging multifunctional materials such as phase-change composites, nanostructured coatings, and perovskite-integrated systems also show promise in enhancing facade adaptability and energy responsiveness. Full article
(This article belongs to the Special Issue Sustainable Development of Energy and Environment in Buildings)
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39 pages, 3629 KiB  
Review
Radiative Heat Transfer Properties of Fiber–Aerogel Composites for Thermal Insulation
by Mohanapriya Venkataraman, Sebnem Sözcü and Jiří Militký
Gels 2025, 11(7), 538; https://doi.org/10.3390/gels11070538 - 11 Jul 2025
Viewed by 502
Abstract
Fiber–aerogel composites have gained significant attention as high-performance thermal insulation materials due to their unique microstructure, which suppresses conductive, convective, and radiative heat transfer. At room temperature, silica aerogels in particular exhibit ultralow thermal conductivity (<0.02 W/m·K), which is two to three times [...] Read more.
Fiber–aerogel composites have gained significant attention as high-performance thermal insulation materials due to their unique microstructure, which suppresses conductive, convective, and radiative heat transfer. At room temperature, silica aerogels in particular exhibit ultralow thermal conductivity (<0.02 W/m·K), which is two to three times lower than that of still air (0.026 W/m·K). Their brittle skeleton and high infrared transparency, however, restrict how well they insulate, particularly at high temperatures (>300 °C). Incorporating microscale fibers into the aerogel matrix enhances mechanical strength and reduces radiative heat transfer by increasing scattering and absorption. For instance, it has been demonstrated that adding glass fibers reduces radiative heat transmission by around 40% because of increased infrared scattering. This review explores the fundamental mechanisms governing radiative heat transfer in fiber–aerogel composites, emphasizing absorption, scattering, and extinction coefficients. We discuss recent advancements in fiber-reinforced aerogels, focusing on material selection, structural modifications, and predictive heat transfer models. Recent studies indicate that incorporating fiber volume fractions as low as 10% can reduce the thermal conductivity of composites by up to 30%, without compromising their mechanical integrity. Key analytical and experimental methods for determining radiative properties, including Fourier transform infrared (FTIR) spectroscopy and numerical modeling approaches, are examined. The emissivity and transmittance of fiber–aerogel composites have been successfully measured using FTIR spectroscopy; tests show that fiber reinforcement at high temperatures reduces emissivity by about 15%. We conclude by outlining the present issues and potential avenues for future research to optimize fiber–aerogel composites for high-temperature applications, including energy-efficient buildings (where long-term thermal stability is necessary), electronics thermal management systems, and aerospace (where temperatures may surpass 1000 °C), with a focus on improving the materials’ affordability and scalability for industrial applications. Full article
(This article belongs to the Special Issue Synthesis and Application of Aerogel (2nd Edition))
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29 pages, 4054 KiB  
Article
Investigation of Convective and Radiative Heat Transfer of 21700 Lithium-Ion Battery Cells
by Gábor Kovács, Szabolcs Kocsis Szürke and Szabolcs Fischer
Batteries 2025, 11(7), 246; https://doi.org/10.3390/batteries11070246 - 26 Jun 2025
Viewed by 580
Abstract
Due to their high energy density and power potential, 21700 lithium-ion battery cells are a widely used technology in hybrid and electric vehicles. Efficient thermal management is essential for maximizing the performance and capacity of Li-ion cells in both low- and high-temperature operating [...] Read more.
Due to their high energy density and power potential, 21700 lithium-ion battery cells are a widely used technology in hybrid and electric vehicles. Efficient thermal management is essential for maximizing the performance and capacity of Li-ion cells in both low- and high-temperature operating conditions. Optimizing thermal management systems remains critical, particularly for long-range and weight-sensitive applications. In these contexts, passive heat dissipation emerges as an ideal solution, offering effective thermal regulation with minimal additional system weight. This study aims to deepen the understanding of passive heat dissipation in 21700 battery cells and optimize their performance. Special emphasis is placed on analyzing heat transfer and the relative contributions of convective and radiative mechanisms under varying temperature and discharge conditions. Laboratory experiments were conducted under controlled environmental conditions at various discharge rates, ranging from 0.5×C to 5×C. A 3D-printed polymer casing was applied to the cell to enhance thermal dissipation, designed specifically to increase radiative heat transfer while minimizing system weight and reliance on active cooling solutions. Additionally, a numerical model was developed and optimized using experimental data. This model simulates convective and radiative heat transfer mechanisms with minimal computational demand. The optimized numerical model is intended to facilitate further investigation of the cell envelope strategy at the module and battery pack levels in future studies. Full article
(This article belongs to the Special Issue Rechargeable Batteries)
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27 pages, 1091 KiB  
Review
Advances in Thermoregulating Textiles: Materials, Mechanisms, and Applications
by Kuok Ho Daniel Tang
Textiles 2025, 5(2), 22; https://doi.org/10.3390/textiles5020022 - 11 Jun 2025
Viewed by 1612
Abstract
Advancements in thermoregulating textiles have been propelled by innovations in nanotechnology, composite materials, and smart fiber engineering. This article reviews recent scholarly papers on experimental passive and active thermoregulating textiles to present the latest advancements in these fabrics, their mechanisms of thermoregulation, and [...] Read more.
Advancements in thermoregulating textiles have been propelled by innovations in nanotechnology, composite materials, and smart fiber engineering. This article reviews recent scholarly papers on experimental passive and active thermoregulating textiles to present the latest advancements in these fabrics, their mechanisms of thermoregulation, and their feasibility for use. The review underscores that phase-change materials enhanced with graphene, boron nitride, and carbon nanofibers offer superior thermal conductivity, phase stability, and flexibility, making them ideal for wearable applications. Shape-stabilized phase-change materials and aerogel-infused fibers have shown promising results in outdoor, industrial, and emergency settings due to their durability and high insulation efficiency. Radiative cooling textiles, engineered with hierarchical nanostructures and Janus wettability, demonstrate passive temperature regulation through selective solar reflection and infrared emission, achieving substantial cooling effects without external energy input. Thermo-responsive, shape-memory materials, and moisture-sensitive polymers enable dynamic insulation and actuation. Liquid-cooling garments and thermoelectric hybrids deliver precise temperature control but face challenges in portability and power consumption. While thermoregulating textiles show promise, the main challenges include achieving scalable manufacturing, ensuring material flexibility, and integrating multiple functions without sacrificing comfort. Future research should focus on hybrid systems combining passive and active mechanisms, user-centric wearability studies, and cost-effective fabrication methods. These innovations hold significant potential for applications in extreme environments, athletic wear, military uniforms, and smart clothing, contributing to energy efficiency, health, and comfort in a warming climate. Full article
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23 pages, 5923 KiB  
Article
Sustainable Increase in Thermal Resistance of Window Construction: Experimental Verification and CFD Modelling of the Air Cavity Created by a Shutter
by Borys Basok, Volodymyr Novikov, Anatoliy Pavlenko, Hanna Koshlak, Svitlana Goncharuk, Oleksii Shmatok and Dmytro Davydenko
Materials 2025, 18(12), 2702; https://doi.org/10.3390/ma18122702 - 9 Jun 2025
Viewed by 627
Abstract
This study investigates, both experimentally and theoretically, the impact of incorporating window shutters on the thermal resistance of double-glazed window units, employing computational fluid dynamics (CFD) modelling. The integration of shutters, whether installed internally or externally, introduces an additional air layer that significantly [...] Read more.
This study investigates, both experimentally and theoretically, the impact of incorporating window shutters on the thermal resistance of double-glazed window units, employing computational fluid dynamics (CFD) modelling. The integration of shutters, whether installed internally or externally, introduces an additional air layer that significantly influences heat transfer between indoor and outdoor environments. This effect on the thermal performance of the transparent structure was analysed through experimental measurements under real operating conditions and numerical simulations involving fluid dynamics and energy equations for the air gaps, alongside heat conduction equations for the solid components. Fourth-kind boundary conditions, considering both radiative and conductive components of the total heat flux emanating from the building’s interior, were applied at the solid–gas interfaces. The simulation results, comparing heat transfer through double-glazed windows with and without shutters, demonstrate a substantial increase in thermal resistance, ranging from 2 to 2.5 times, upon shutter implementation. These findings underscore the effectiveness of employing shutters as a strategy to enhance the energy efficiency of windows and, consequently, the overall energy performance of buildings. This research contributes to the advancement of sustainable materials for engineering applications by providing insights into the optimisation of thermal performance in building envelopes. Full article
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18 pages, 9739 KiB  
Article
Fractal-Based Thermal Conductivity Prediction Modeling for Closed Mesoporous Polymer Gels
by Haiyan Yu, Mingdong Li, Ning Guo, Anqi Chen, Haochun Zhang and Mu Du
Gels 2025, 11(6), 391; https://doi.org/10.3390/gels11060391 - 26 May 2025
Viewed by 426
Abstract
The closed mesoporous polymer gels have garnered significant attention as advanced thermal insulation materials due to their superior lightweight characteristics and excellent thermal management capabilities. To accurately predict their thermal performance, this study develops a novel mathematical model that integrates fractal geometry theory, [...] Read more.
The closed mesoporous polymer gels have garnered significant attention as advanced thermal insulation materials due to their superior lightweight characteristics and excellent thermal management capabilities. To accurately predict their thermal performance, this study develops a novel mathematical model that integrates fractal geometry theory, Kirchhoff’s thermal conduction principles, comprehensive Rosseland diffusion approximation, and Mie scattering theory. The conductive thermal conductivity component was formulated based on a diagonal cross fractal structure, while the radiative component was derived considering microscale radiative effects. Model predictions exhibit strong agreement with experimental results from various mesoporous polymer gels, achieving a prediction error of less than 11.2%. Furthermore, a detailed parametric analysis was conducted, elucidating the influences of porosity, cell size, temperature, refractive index, and extinction coefficient. The findings identify a critical cell size range (1–100 µm) and porosity range (0.74–0.97) where minimum thermal conductivity occurs. This proposed modeling approach offers a robust and efficient theoretical tool for designing and optimizing the thermal insulation characteristics of closed mesoporous polymer gels, thereby advancing their application in diverse energy conversion and management systems. Full article
(This article belongs to the Special Issue Characterization Techniques for Hydrogels and Their Applications)
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19 pages, 11685 KiB  
Article
Thermal Insulation Foam of Polystyrene/Expanded Graphite Composite with Reduced Radiation and Conduction
by Pengjian Gong, Minh-Phuong Tran, Piyapong Buahom, Christophe Detrembleur, Jean-Michel Thomassin, Samuel Kenig, Quanbing Wang and Chul B. Park
Polymers 2025, 17(8), 1040; https://doi.org/10.3390/polym17081040 - 11 Apr 2025
Cited by 1 | Viewed by 1107
Abstract
Expanded graphite (EG) with high infrared (IR) absorption is incorporated at low concentrations (≤2 wt%) into polystyrene (PS) foams to reduce radiative thermal conductivity and solid thermal conductivity, which account for 20~40% and 10~30% of total thermal conductivity, respectively. After systematically and quantitatively [...] Read more.
Expanded graphite (EG) with high infrared (IR) absorption is incorporated at low concentrations (≤2 wt%) into polystyrene (PS) foams to reduce radiative thermal conductivity and solid thermal conductivity, which account for 20~40% and 10~30% of total thermal conductivity, respectively. After systematically and quantitatively investigating thermal insulation behavior in PS/EG foams, it was found that the inclusion of 1 wt% EG in 25-fold expanded PS/EG foam blocks over 90% of the radiative thermal conductivity, with only a marginal increase in heat conduction. A great reduction in total thermal conductivity from 36.5 to 30.2 mW·m−1·K−1 was then achieved. By further optimization using a co-blowing agent in the supercritical CO2 foaming process, superthermal insulating PS/EG foam with a total thermal conductivity of 19.6 mW·m−1·K−1 was achieved for the first time. This significant result implies that the composite material design together with the foaming process design is capable of obtaining a superthermal insulating composite foam by using the following strategy: using additives with high IR absorption efficiency, a foam with a large expansion ratio, and a co-blowing agent with low gas conductivity. Full article
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15 pages, 6710 KiB  
Article
Development and Validation of an Electromagnetic Induction-Based Thermal Propagation Test Method for Large-Format Lithium-Ion Battery Systems
by Changyong Jin, Jiangna Gu, Chengshan Xu, Wanlin Wang, Lirong Liu and Xuning Feng
Batteries 2025, 11(4), 148; https://doi.org/10.3390/batteries11040148 - 9 Apr 2025
Viewed by 817
Abstract
This study establishes a standardized framework for thermal propagation test in nickel-7 lithium-ion battery systems through a high-frequency electromagnetic induction heating method. The non-intrusive triggering mechanism enables precise thermal runaway initiation within two seconds through localized eddy current heating (>1200 °C), validated through [...] Read more.
This study establishes a standardized framework for thermal propagation test in nickel-7 lithium-ion battery systems through a high-frequency electromagnetic induction heating method. The non-intrusive triggering mechanism enables precise thermal runaway initiation within two seconds through localized eddy current heating (>1200 °C), validated through cell-level tests with 100% success rate across diverse trigger positions. System-level thermal propagation tests were conducted on two identical battery boxes. The parallel experiments revealed distinct propagation patterns influenced by system sealing quality. In the inadequately sealed system (Box 01), flame formation led to accelerated thermal propagation through enhanced convective and radiative heat transfer. In contrast, the well-sealed system (Box 02) maintained an oxygen-deficient environment, resulting in a controlled sequential propagation pattern. The testing methodology incorporating dummy modules proved efficient for validating thermal protection strategies while optimizing costs. This study contributes to a deeper understanding of thermal runaway propagation mechanisms and the development of standardized testing protocols for large-format battery systems. Full article
(This article belongs to the Special Issue Battery Safety and Fire Prevention in Electric Vehicles)
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20 pages, 11969 KiB  
Article
A Novel Prediction Model for Thermal Conductivity of Open Microporous Metal Foam Based on Resonance Enhancement Mechanisms
by Anqi Chen, Jialong Chai, Xiaohan Ren, Mingdong Li, Haiyan Yu and Guilong Wang
Energies 2025, 18(6), 1529; https://doi.org/10.3390/en18061529 - 20 Mar 2025
Cited by 1 | Viewed by 523
Abstract
Microporous metal materials have promising applications in the high-temperature industry for their high heat exchange efficiency. However, due to their complex internal structure, analyzing the heat transfer mechanisms presents a great challenge. This I confirm work introduces a mathematical model to accurately calculate [...] Read more.
Microporous metal materials have promising applications in the high-temperature industry for their high heat exchange efficiency. However, due to their complex internal structure, analyzing the heat transfer mechanisms presents a great challenge. This I confirm work introduces a mathematical model to accurately calculate the radiative thermal conductivity of microporous open-cell metal materials. The finite element and lattice Boltzmann methods were employed to calculate the thermal conduction and thermal radiation conductivities separately and validated for aluminum foams, with the relative errors all less than 9.3%. The results show that the thermal conductivity of microporous metal materials mainly increased with an increase in temperature and volume-specific surface area but decreased with an increase in porosity. Analysis of the spectral radiation characteristics shows that the surface plasmon polariton resonance and the magnetic polariton resonance appearing at the gas–solid interface of the metal foam significantly increase the dissipation effect of the gas–solid interface, further reducing the metal foam’s heat transfer efficiency. This indicates the potential of this work for use in the design of specific microporous metal materials like energy management devices or heat transfer exchangers in the aerospace industry. Full article
(This article belongs to the Section J: Thermal Management)
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13 pages, 2308 KiB  
Article
A Large-Scale Preparation Approach for Daytime Radiative Cooling Using SiO2 Hollow Microsphere Composite Film
by Changhai Li, Xiaojie Sun, Yuting Yang, Baojian Liu, Haotian Zhang, Rong He, Rongjun Zhang, Yuxiang Zheng, Songyou Wang, Young-Pak Lee and Liangyao Chen
Coatings 2025, 15(3), 340; https://doi.org/10.3390/coatings15030340 - 14 Mar 2025
Viewed by 824
Abstract
Radiative cooling is a passive cooling strategy that dissipates heat externally through the atmospheric window (8–13 μm). This study presents a radiative cooling film with a simple and cost-effective fabrication process. The film was fabricated by mixing SiO2 hollow microspheres with a [...] Read more.
Radiative cooling is a passive cooling strategy that dissipates heat externally through the atmospheric window (8–13 μm). This study presents a radiative cooling film with a simple and cost-effective fabrication process. The film was fabricated by mixing SiO2 hollow microspheres with a UV-curable resin, employing a photopolymerization-induced phase separation method. The resulting gradient refractive index structure enhanced thermal radiation emissivity. At an optimal silica-to-resin mass ratio of 1:1.5 and a film thickness of 1.1 mm, the film achieved a solar reflectivity of 85% and an emissivity of 91% within the atmospheric window. Outdoor experiments conducted in both summer and winter demonstrated stable cooling performance. Under a solar irradiance of 796.9 W/m2 (summer), the film reduced surface temperature by 10 °C compared to ambient air and 20 °C compared to an uncoated glass substrate, achieving a radiative cooling power of 76.7 W/m2. In winter (solar irradiance of 588.8 W/m2), the film maintained a significant cooling effect, though with reduced efficiency due to lower solar exposure. Furthermore, long-term stability tests over six months showed that the film retained high solar reflectivity and infrared emissivity, indicating good durability. Overall, the developed radiative cooling films demonstrate excellent optical properties, structural stability, and cooling efficiency, making it a promising candidate for real-world radiative cooling applications. Further studies on environmental resilience and optimization under diverse climatic conditions are necessary for broader deployment. Full article
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24 pages, 7418 KiB  
Article
Computational Fluid Dynamics Analysis of Radiation Characteristics in Gas–Iron Ore Particle Reactive Flow Processes at an Industrial-Scale in a Hydrogen-Based Flash Smelting Furnace
by Yuchen Feng, Mingzhou Li, Shiyu Lai, Jindi Huang, Zhanghao Wan, Weilin Xiao and Tengwei Long
Metals 2025, 15(3), 242; https://doi.org/10.3390/met15030242 - 25 Feb 2025
Viewed by 738
Abstract
Iron smelting is one of the primary sources of carbon emissions. The development of low-carbon ironmaking technologies is essential for the iron and steel industry to realize the “dual carbon” ambition. Hydrogen-based flash ironmaking technology eliminates traditional pretreatment steps such as sintering, pelletizing, [...] Read more.
Iron smelting is one of the primary sources of carbon emissions. The development of low-carbon ironmaking technologies is essential for the iron and steel industry to realize the “dual carbon” ambition. Hydrogen-based flash ironmaking technology eliminates traditional pretreatment steps such as sintering, pelletizing, and coking while using hydrogen as a reducing agent, significantly reducing carbon emissions. In the present work, a computational fluid dynamics approach is employed to conduct an in-depth analysis of the radiative properties inside the reaction shaft of a flash smelting furnace. The results illustrate that the lowest gas absorption coefficient and volumetric absorption radiation along the radial direction appear at y = 2.84 m, with the values of 0.085 m−1 and 89,364.6 W/m3, respectively, whereas the largest values for these two variables in the axial direction can be obtained at h = 6.14 m with values of 0.128 m−1 and 132,841.11 W/m3. The reduced incident radiation intensity under case 1’s condition led to distinct differences in the radiative temperature compared to the other four cases. The spatial distributions of the particle absorption and scattering coefficients exhibit excellent consistency. The thermal conductivities of all investigated cases depict similar trends along both the axial and radial directions. Volumetric emissive radiation presents a non-linear trend of first increasing and then decreasing, followed by the rise as the height decreases. This study highlights the critical role of hydrogen-based flash ironmaking technology in reducing carbon emissions and provides valuable insights into the radiative characteristics of its reaction shaft under different operating conditions. Full article
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12 pages, 4890 KiB  
Article
Cryogenic Facility for Prototyping ET-LF Payloads Using Conductive Cooling
by Marco Ricci, Eugenio Benedetti, Angelo Cruciani, Van Long Hoang, Benedetta Kalemi, Luca Naticchioni, Marco Orsini, Stefano Pirro, Paola Puppo, Piero Rapagnani, Fulvio Ricci, Emanuele Tofani and Ettore Majorana
Galaxies 2025, 13(1), 12; https://doi.org/10.3390/galaxies13010012 - 12 Feb 2025
Viewed by 842
Abstract
Cooling down large test masses up to 200 kg, as foreseen for the Einstein Telescope, is a complex challenge combining cutting-edge technological achievements from different disciplines with the experience gained from both room-temperature and cryogenic-temperature detector development communities. We set up an apparatus [...] Read more.
Cooling down large test masses up to 200 kg, as foreseen for the Einstein Telescope, is a complex challenge combining cutting-edge technological achievements from different disciplines with the experience gained from both room-temperature and cryogenic-temperature detector development communities. We set up an apparatus designed to test cryogenic mechanical suspensions for the payload system. They should have high quality factors and enable sufficient heat extraction greater than 0.3 W. The facility is on a university campus where cryofluid servicing is not feasible. As a result, a system that incorporates conductive cooling technology was developed. The project has two main goals: validating crystalline suspensions in a realistic Einstein Telescope cryogenic payload and testing new solutions for radiative thermal shielding. No particular measures are planned for the vibration isolation system. Full article
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14 pages, 5367 KiB  
Article
Reducing Infrared Radiation and Solid Thermal Conductivity by Incorporating Varying Amounts of GnP into Microcellular PMMA
by Antonio Largo-Barrientos, Beatriz Merillas, Ismael Sánchez-Calderón, Miguel Angel Rodríguez-Pérez and Judith Martín-de León
Polymers 2025, 17(4), 471; https://doi.org/10.3390/polym17040471 - 11 Feb 2025
Viewed by 1044
Abstract
Although microcellular foams are potential thermal insulators, their low density and small pore size allow infrared radiation to pass through, increasing the effective thermal conductivity. To address this drawback, graphene nanoplatelets (GnPs) have previously been added to polymethylmethacrylate (PMMA) samples as infrared blockers, [...] Read more.
Although microcellular foams are potential thermal insulators, their low density and small pore size allow infrared radiation to pass through, increasing the effective thermal conductivity. To address this drawback, graphene nanoplatelets (GnPs) have previously been added to polymethylmethacrylate (PMMA) samples as infrared blockers, enhancing insulation by reducing the radiative component of heat transfer. In this work, the effect of the content of GnPs is studied. Cellular PMMA samples with GnP contents ranging from 0.5 to 10 weight total percentage (wt. %) and pore sizes between 2 and 5 microns were tested. Thermal conductivity measurements showed that GnP additions from 0.5 to 5 wt. % significantly decrease the radiative term, achieving a 33% reduction compared to pure PMMA and reaching thermal conductivity values of 38 mW m−1 K−1. Moreover, the structural factor is diminished up to 45% in comparison to pure microcellular PMMA, which, in samples with contents of GnPs such as 1 wt. %, results in a reduction in the conductivity of the solid phase. This approach demonstrates that incorporating small contents of GnPs effectively enhances the thermal performance of microcellular foams, a strategy that could be applied to other polymers to achieve better thermal insulation properties. Full article
(This article belongs to the Section Polymer Composites and Nanocomposites)
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21 pages, 4994 KiB  
Article
Trade-Off Studies of a Radiantly Integrated TPV-Microreactor (RITMS) Design
by Naiki Kaffezakis and Dan Kotlyar
Energies 2025, 18(3), 659; https://doi.org/10.3390/en18030659 - 31 Jan 2025
Viewed by 892
Abstract
Advancements in thermophotovoltaic (TPV) technologies enable a new alternative for the electrification of nuclear power. These solid-state heat engines are more robust and likely cheaper to manufacture than the turbomachinery used in traditional microreactor concepts. The Radiantly Integrated TPV-microreactor system (RITMS) described in [...] Read more.
Advancements in thermophotovoltaic (TPV) technologies enable a new alternative for the electrification of nuclear power. These solid-state heat engines are more robust and likely cheaper to manufacture than the turbomachinery used in traditional microreactor concepts. The Radiantly Integrated TPV-microreactor system (RITMS) described in this work takes a novel approach to utilizing direct electric conversion of thermal power radiated from the active core. Without intermediary energy transfer, this direct coupling allows for system efficiencies well above 30%. While providing an introduction to the concept, the early RITMS work lacked an integrated computational sequence and economics-by-design approach, resulting in a failure to fully capture the physics of the system or to properly evaluate design parameter importance. The primary purpose of this paper is to describe and demonstrate a computational sequence that fully couples the conductive-radiative heat transfer with a neutronic solution and to provide design-specific cost estimation. This new computational framework is deployed in re-examining the multi-physics behavior of the RITMS design and to perform consistent trade-off studies. A favorable RITMS design was selected based on performance and fuel cycle costs, which was deemed feasible when considering cost uncertainty. Able to operate on 7% enriched fuel, this RITMS case was selected to balance fuel utilization with total power output. Full article
(This article belongs to the Special Issue Advances in Nuclear Power for Integrated Energy Systems)
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