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20 pages, 4023 KiB  
Article
Numerical Study on the Thermal Behavior of Lithium-Ion Batteries Based on an Electrochemical–Thermal Coupling Model
by Xing Hu, Hu Xu, Chenglin Ding, Yupeng Tian and Kuo Yang
Batteries 2025, 11(7), 280; https://doi.org/10.3390/batteries11070280 - 21 Jul 2025
Viewed by 426
Abstract
The escalating demand for efficient thermal management in lithium-ion batteries necessitates precise characterization of their thermal behavior under diverse operating conditions. This study develops a three-dimensional (3D) electrochemical–thermal coupling model grounded in porous electrode theory and energy conservation principles. The model solves multi-physics [...] Read more.
The escalating demand for efficient thermal management in lithium-ion batteries necessitates precise characterization of their thermal behavior under diverse operating conditions. This study develops a three-dimensional (3D) electrochemical–thermal coupling model grounded in porous electrode theory and energy conservation principles. The model solves multi-physics equations such as Fick’s law, Ohm’s law, and the Butler–Volmer equation, to resolve coupled electrochemical and thermal dynamics, with temperature-dependent parameters calibrated via the Arrhenius equation. Simulations under varying discharge rates reveal that high-rate discharges exacerbate internal heat accumulation. Low ambient temperatures amplify polarization effects. Forced convection cooling reduces surface temperatures but exacerbates core-to-surface thermal gradients. Structural optimization strategies demonstrate that enhancing through-thickness thermal conductivity reduces temperature differences. These findings underscore the necessity of balancing energy density and thermal management in lithium-ion battery design, proposing actionable insights such as preheating protocols for low-temperature operation, optimized cooling systems for high-rate scenarios, and material-level enhancements for improved thermal uniformity. Full article
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20 pages, 845 KiB  
Article
Designing a Waste Heat Recovery Heat Exchanger for Polymer Electrolyte Membrane Fuel Cell Operation in Medium-Altitude Unmanned Aerial Vehicles
by Juwon Jang, Jaehyung Choi, Seung-Jun Choi and Seung-Gon Kim
Energies 2025, 18(13), 3262; https://doi.org/10.3390/en18133262 - 22 Jun 2025
Viewed by 348
Abstract
Polymer electrolyte membrane fuel cells (PEMFCs) are emerging as the next-generation powertrain for unmanned aerial vehicles (UAVs) due to their high energy density and long operating duration. PEMFCs are subject to icing and performance degradation problems at sub-zero temperatures, especially at high altitudes. [...] Read more.
Polymer electrolyte membrane fuel cells (PEMFCs) are emerging as the next-generation powertrain for unmanned aerial vehicles (UAVs) due to their high energy density and long operating duration. PEMFCs are subject to icing and performance degradation problems at sub-zero temperatures, especially at high altitudes. Therefore, an effective preheating system is required to ensure stable PEMFC operation in high-altitude environments. This study aimed to mathematically model a shell-and-tube heat exchanger that utilizes waste heat recovery to prevent internal and external PEMFC damage in cold, high-altitude conditions. The waste heat from the PEMFC is estimated based on the thrust of the MQ-9 Reaper, and the proposed heat exchanger must be capable of heating air to −5 °C. As the heat exchanger utilizes only waste heat, the primary energy consumption arises from the coolant pumping process. Calculation results indicated that the proposed heat exchanger design improved the overall system efficiency by up to 15.7%, demonstrating its effectiveness in utilizing waste heat under aviation conditions. Full article
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15 pages, 6632 KiB  
Article
Thermal Management and Energy Recovery in Commercial Dishwashers: A Theoretical and Experimental Study
by Jafar Zanganeh, Adrian Seyfaee, Greg Gates and Behdad Moghtaderi
Energies 2025, 18(9), 2338; https://doi.org/10.3390/en18092338 - 3 May 2025
Viewed by 460
Abstract
This paper presents a theoretical and experimental investigation into improving the energy efficiency of electrically heated systems through thermal energy recovery. Enhancing efficiency in such systems can significantly reduce energy consumption, operating costs, and greenhouse gas emissions, particularly when electricity is generated from [...] Read more.
This paper presents a theoretical and experimental investigation into improving the energy efficiency of electrically heated systems through thermal energy recovery. Enhancing efficiency in such systems can significantly reduce energy consumption, operating costs, and greenhouse gas emissions, particularly when electricity is generated from fossil fuels. Commercial dishwashers are inherently energy-intensive due to the need for rapid and effective cleaning. Regulatory and market pressures increasingly encourage manufacturers to develop energy-efficient technologies. This study aimed to design, develop, and incorporate a miniaturized heat exchanger to recover waste thermal energy and reduce the overall energy consumption in a commercial dishwasher. In collaboration with Norris Industries, the University of Newcastle trialed a retrofitted internal heat exchanger in representative commercial dishwasher models. The device was designed to transfer heat from discharged wash water to preheat incoming freshwater. The heat exchanger was developed based on a theoretical thermal analysis and engineered for practical integration. Experimental testing demonstrated that the system achieved up to a 50% reduction in energy use without compromising the cleaning performance or increasing the manufacturing complexity. This approach offers a scalable and effective solution for enhancing energy efficiency in commercial dishwashing. Its broader implementation could substantially reduce the energy demand and greenhouse gas emissions across the sector. Full article
(This article belongs to the Section J: Thermal Management)
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18 pages, 22994 KiB  
Article
Design of a Proton Exchange Membrane Electrolyzer
by Torsten Berning
Hydrogen 2025, 6(2), 30; https://doi.org/10.3390/hydrogen6020030 - 2 May 2025
Viewed by 2925
Abstract
A novel design of a proton exchange membrane electrolyzer is presented. In contrast to previous designs, the flow field plates are round and oriented horizontally with the feed water entering from a central hole and spreading evenly outward over the anode flow field [...] Read more.
A novel design of a proton exchange membrane electrolyzer is presented. In contrast to previous designs, the flow field plates are round and oriented horizontally with the feed water entering from a central hole and spreading evenly outward over the anode flow field in radial, interdigitated flow channels. The cathode flow field consists of a spiral channel with an outlet hole near the outside of the bipolar plate. This results in anode and cathode flow channels that run perpendicular to avoid shear stresses. The novel sealing concept requires only o-rings, which press against the electrolyte membrane and are countered by circular gaskets that are placed over the flow channels to prevent the membrane from penetrating the channels, which makes for a much more economical sealing concept compared to prior designs using custom-made gaskets. Hydrogen leaves the electrolyzer through a vertical outward pipe placed off-center on top of the electrolyzer. The electrolyzer stack is housed in a cylinder to capture the oxygen and water vapor, which is then guided into a heat exchanger section, located underneath the electrolyzer partition. The function of the heat exchanger is to preheat the incoming fresh water and condense the escape water, thus improving the efficiency. It also serves as internal phase separator in that a level sensor controls the water level and triggers a recirculation pump for the condensate, while the oxygen outlet is located above the water level and can be connected to a vacuum pump to allow for electrolyzer operation at sub-ambient pressure to further increase efficiency and/or reduce the iridium loading. Full article
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44 pages, 15119 KiB  
Review
Review of Ammonia Oxy-Combustion Technologies: Fundamental Research and Its Various Applications
by Novianti Dwi, Kurniawati Ischia and Yonmo Sung
Energies 2025, 18(9), 2252; https://doi.org/10.3390/en18092252 - 28 Apr 2025
Cited by 1 | Viewed by 1071
Abstract
The combustion of ammonia with oxygen presents a promising pathway for global energy transformation using carbon dioxide-neutral energy solutions and carbon capture. Ammonia, a carbon-free fuel, offers several benefits, owing to its non-explosive nature, high octane rating, and ease of storage and distribution. [...] Read more.
The combustion of ammonia with oxygen presents a promising pathway for global energy transformation using carbon dioxide-neutral energy solutions and carbon capture. Ammonia, a carbon-free fuel, offers several benefits, owing to its non-explosive nature, high octane rating, and ease of storage and distribution. However, challenges such as low flammability and excessive nitrogen oxide (NOx) emissions must be addressed. This paper explores the recent advances in ammonia oxy-combustion and highlights recent experimental and numerical research on NOx emission traits, combustion, and flame propagation across various applications, including gas furnaces, internal combustion engines, and boilers. Furthermore, this review discusses the diverse approaches to overcoming the challenges of ammonia combustion, including oxygen enrichment, fuel blending, plasma assistance, preheating, multiple injections, and burner design modifications. By summarizing the advancements in ammonia oxy-combustion investigation, this paper aims to provide valuable insights that can serve as reference information for prospective ammonia oxy-combustion research and applications toward the transition to sustainable energy. Full article
(This article belongs to the Section B: Energy and Environment)
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13 pages, 1567 KiB  
Article
Preheated and Injected Bulk-Fill Resin Composites: A Micro-CT Analysis of Internal Voids and Marginal Adaptation in Class II Restorations
by Vanessa Alves de Sá, Hélio Radke Bittencourt, Luiz Henrique Burnett Júnior and Ana Maria Spohr
Materials 2025, 18(2), 327; https://doi.org/10.3390/ma18020327 - 13 Jan 2025
Cited by 3 | Viewed by 1119
Abstract
The aim of this study was to evaluate, in vitro, the void formation and marginal adaptation in Class II cavities restored with preheated and injected bulk-fill resin composites. Eighty third molars received Class II cavities on their mesial and distal surfaces and were [...] Read more.
The aim of this study was to evaluate, in vitro, the void formation and marginal adaptation in Class II cavities restored with preheated and injected bulk-fill resin composites. Eighty third molars received Class II cavities on their mesial and distal surfaces and were randomly distributed into eight groups (n = 10) according to material (Filtek Universal—control, incremental technique; Filtek One Bulk-Fill; Admira Fusion X-tra Bulk-Fill; VisCalor Bulk-Fill) and the temperature of the material (24 °C or 68 °C). The restored teeth were scanned using a SkyScan 1173 microtomograph. The percentage of internal voids (%IV) was analyzed using CTan software (version 1.23.02) and the percentages of continuous margins (%CM) in enamel and dentin were analyzed using Dataviewer software (version 1.5.6.2). The data of %IV and %CM were subjected to two-way ANOVA on ranks, followed by Tukey’s test (α = 0.05). At 24 °C, Filtek Universal had a greater %IV (1.89%) (p < 0.05), which did not differ significantly from that of Admira Fusion X-tra Bulk-Fill (0.29%) (p > 0.05). Filtek One Bulk-Fill (0.07%) and VisCalor Bulk-Fill (0.07%) had lower %IV (p < 0.05). Preheating resulted in a significantly lower %IV for Admira Fusion X-tra Bulk-Fill (p < 0.05). Temperature did not significantly influence marginal adaptation (p > 0.05). VisCalor Bulk-Fill achieved significantly higher %CM in dentin (98%) at 24 °C (p < 0.05). It was concluded that bulk-fill-injected resin composites tend to have fewer internal voids than conventional resin composites using the incremental technique, and the injection of the resin composite into the cavity seems to be more important for marginal adaptation than the preheating procedure. Full article
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32 pages, 5622 KiB  
Article
Performance Enhancement of a Building-Integrated Photovoltaic/Thermal System Coupled with an Air Source Heat Pump
by Edward Vuong, Alan S. Fung and Rakesh Kumar
Energies 2025, 18(1), 12; https://doi.org/10.3390/en18010012 - 24 Dec 2024
Cited by 3 | Viewed by 975
Abstract
This study explores the improvement of building integrated photovoltaic–thermal (BIPV/T) systems and their integration with air source heat pumps (ASHPs). The BIPV/T collector needs a method to effectively extract the heat it collects, while ASHP can boost their efficiency utilizing preheated air from [...] Read more.
This study explores the improvement of building integrated photovoltaic–thermal (BIPV/T) systems and their integration with air source heat pumps (ASHPs). The BIPV/T collector needs a method to effectively extract the heat it collects, while ASHP can boost their efficiency utilizing preheated air from the BIPV/T collectors. Combining these two systems presents a valuable opportunity to enhance their performance. This paper discusses technological improvements and integration through a comprehensive modelling analysis. Two versions of the BIPV/T systems were assessed using a modified version of EnergyPlus V8.0, a building energy simulation program. This study involved sensitivity analysis of the internal channel surface and cover emissivity parameters of the opaque BIPV/T (OBIPV/T), transparent BIPV/T (TBIPV/T), and building-integrated solar air heater collectors (BISAHs). Various arrangements of the collectors were also studied. A BIPV/T-BISAH array design was selected based on the analysis, and its integration with a net-zero energy house. The BIPV/T-BISAH coupled ASHP system decreased space heating electricity consumption by 6.5% for a net-zero house. These modest savings are mainly attributed to the passive design of the houses, which reduced heating loads during sunny hours/days. Full article
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16 pages, 5378 KiB  
Article
Results on the Use of an Original Burner for Reducing the Three-Way Catalyst Light-Off Time
by Adrian Clenci, Bogdan Cioc, Julien Berquez, Victor Iorga-Simăn, Robert Stoica and Rodica Niculescu
Inventions 2024, 9(6), 112; https://doi.org/10.3390/inventions9060112 - 29 Oct 2024
Cited by 1 | Viewed by 1368
Abstract
Individual road mobility comes with two major challenges: greenhouse gas emissions related to global warming and chemical pollution. For the pollution reduction in the spark ignition engine vehicle, the standard and reliable aftertreatment technology is the three-way catalytic converter (TWC). However, the TWC [...] Read more.
Individual road mobility comes with two major challenges: greenhouse gas emissions related to global warming and chemical pollution. For the pollution reduction in the spark ignition engine vehicle, the standard and reliable aftertreatment technology is the three-way catalytic converter (TWC). However, the TWC starts to convert once an optimal temperature, usually known as the light-off temperature, is reached. There are many methods to reduce the warm-up period of the TWC, among which is using a burner. The initial question underlying this study was to see if the use of a relatively straightforward extra-combustion device mounted upstream the TWC, without complex elements, was able to serve the purpose of reducing the light-off time. Consequently, an original burner was designed and investigated numerically via the CFD method and experimentally via measurements of the temperature evolution within a TWC, along with the emissions specific to the burner’s operation. The main findings of this study are: (1) the CFD-based examination is a good way to decide on how to achieve the so-called fit-for-purpose internal aerodynamics of the burner (i.e., to obtain a homogeneous mixture) and (2) to reach the light-off temperature, conventionally taken as 500 K, the burner was operated for 5.2 s, i.e., 3.6 g of gasoline injected, 2.7 g of CO2 and 1.351 g of CO, respectively, emitted. Moreover, this study identified measures for improving the burner’s design as well as an enhanced procedure for the burner’s operating control both aiming to produce a cleaner combustion during the TWC pre-heating. Full article
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12 pages, 3297 KiB  
Article
Temperature Management Strategy for Urban Air Mobility Batteries to Improve Energy Efficiency in Low-Temperature Conditions
by Seon-Woong Kim, Do-Hun Kwon and In-Ho Cho
Sustainability 2024, 16(18), 8201; https://doi.org/10.3390/su16188201 - 20 Sep 2024
Cited by 1 | Viewed by 1850
Abstract
As urban population concentration accelerates, issues such as traffic congestion caused by automobiles and climate change due to carbon dioxide emissions are becoming increasingly severe. Recently, urban air mobility (UAM) has been attracting attention as a solution to these problems. UAM refers to [...] Read more.
As urban population concentration accelerates, issues such as traffic congestion caused by automobiles and climate change due to carbon dioxide emissions are becoming increasingly severe. Recently, urban air mobility (UAM) has been attracting attention as a solution to these problems. UAM refers to a system that uses electric vertical takeoff and landing (eVTOL) aircraft to transport passengers and cargo at low altitudes between key points within urban areas, with lithium-ion batteries as the primary power source. The lithium-ion batteries used in UAM have characteristics that degrade performance in low temperatures, including decreased power output and diminished energy capacity. Although research has been conducted on preheating lithium-ion batteries to address this issue, sufficient consideration has not been given to the energy used for preheating. Therefore, this study compares the energy recovered by preheating lithium-ion batteries with the energy consumed during preheating and proposes a temperature management method for low temperatures that maximizes the energy gain of lithium-ion batteries. Full article
(This article belongs to the Special Issue Advances in Sustainability in Air Transport and Multimodality)
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15 pages, 4909 KiB  
Article
Investigating the Effects of Transition Metals and Activated Carbon on Hydrogenation Characteristics of Severely Deformed ZK60 Processed by High-Energy Ball Milling
by Aqeel Abbas, Tzu-Chieh Hsu, Jhe-Yi Lin, Hung-Cheng Ho, Kun-Ming Lin and Hsin-Chih Lin
Materials 2024, 17(18), 4562; https://doi.org/10.3390/ma17184562 - 17 Sep 2024
Viewed by 941
Abstract
The synergic effects of activated carbon and transition metals on the hydrogenation characteristics of commercial ZK60 magnesium alloy were investigated. Severe plastic deformation was performed using equal-channel angular pressing with an internal die angle of 120° and preheating at 300 °C. The ZK60 [...] Read more.
The synergic effects of activated carbon and transition metals on the hydrogenation characteristics of commercial ZK60 magnesium alloy were investigated. Severe plastic deformation was performed using equal-channel angular pressing with an internal die angle of 120° and preheating at 300 °C. The ZK60 alloy samples were processed for 12 passes using route BA. The deformed ZK60 alloy powder was blended with activated carbon and different concentrations of transition metals (Ag, Pd, Co, Ti, V, Ti) using high-energy ball milling for 20 h at a speed of 1725 rpm. The amount of hydrogen absorbed and its kinetics were calculated using Sievert’s apparatus at the higher number of cycles at a 300 °C ab/desorption temperature. The microstructure of the powder was analyzed using an X-ray diffractometer and scanning electron microscope. The results indicated that 5 wt% activated carbon presented the maximum hydrogen absorption capacity of 6.2 wt%. The optimal hydrogen absorption capacities were 7.1 wt%, 6.8 wt%, 6.7 wt%, 6.64 wt%, 6.65 wt%, and 7.06 wt% for 0.5 Ag, 0.3 Co, 0.1 Al, 0.5 Pd, 2 Ti, and 0.5 V, respectively. The hydrogen absorption capacities were reduced by 35.21%, 26.47%, 41.79%, 21.68%, 26.31%, and 26.34% after 100 cycles for 5C0.5Ag, 5C0.3Co, 5C0.1Al, 5C0.5Pd, 2Ti, and 5C0.5V, respectively. Hydrogen absorption kinetics were significantly improved so that more than 90% of hydrogen was absorbed within five minutes. Full article
(This article belongs to the Section Energy Materials)
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11 pages, 4048 KiB  
Article
Effects of Room-Temperature Center Gas Distributor Injection on the H2 Shaft Furnace Process: A Numerical Study
by Lei Shao, Hongfu Yu and Chenxi Zhao
Processes 2024, 12(8), 1666; https://doi.org/10.3390/pr12081666 - 8 Aug 2024
Viewed by 1420
Abstract
In the current work, a computational fluid dynamics-based model was utilized to investigate the performance of the H2 shaft furnace under a scenario where room-temperature H2 is injected through a center gas distributor (CGD) installed at the unit bottom. Modelling was [...] Read more.
In the current work, a computational fluid dynamics-based model was utilized to investigate the performance of the H2 shaft furnace under a scenario where room-temperature H2 is injected through a center gas distributor (CGD) installed at the unit bottom. Modelling was conducted to simulate scenarios where the CGD operation is applied with different feed gas rates (ranging from 0 to 250 Nm3/t-pellet). The results showed that a high temperature level and thus a better internal thermochemical state can be maintained with a proper CGD gas feed rate. However, an overly high CGD feed rate (being 150 Nm3/t-pellet or a higher value) induces a detrimental scenario where the thermal energy recycled by the room-temperature CGD gas is insufficient to compensate for the decrease of sensible heat of the preheated feed gas from the bustle-pipe. This eventually results in a noteworthy chemical reserve zone of high H2 content and little solid reduction in the furnace center. A large quantity of H2 consequently remains unutilized and leaves the furnace from the top. Under the investigated conditions, the final solid reduction degree rises to maximal value when the CGD gas feed rate is 100 Nm3/t-pellet. The findings of this work revealed that the room-temperature CGD gas injection operation holds significant promise for practical applications. Full article
(This article belongs to the Special Issue Recent Trends in Extractive Metallurgy)
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36 pages, 5097 KiB  
Review
A Review of Thermal Management and Heat Transfer of Lithium-Ion Batteries
by Liang Xu, Shanyi Wang, Lei Xi, Yunlong Li and Jianmin Gao
Energies 2024, 17(16), 3873; https://doi.org/10.3390/en17163873 - 6 Aug 2024
Cited by 12 | Viewed by 7510
Abstract
With the increasing demand for renewable energy worldwide, lithium-ion batteries are a major candidate for the energy shift due to their superior capabilities. However, the heat generated by these batteries during their operation can lead to serious safety issues and even fires and [...] Read more.
With the increasing demand for renewable energy worldwide, lithium-ion batteries are a major candidate for the energy shift due to their superior capabilities. However, the heat generated by these batteries during their operation can lead to serious safety issues and even fires and explosions if not managed effectively. Lithium-ion batteries also suffer from significant performance degradation at low temperatures, including reduced power output, a shorter cycle life, and reduced usable capacity. Deploying an effective battery thermal management system (BTMS) is crucial to address these obstacles and maintain stable battery operation within a safe temperature range. In this study, we review recent developments in the thermal management and heat transfer of Li-ion batteries to offer more effective, secure, and cost-effective solutions. We evaluate different technologies in BTMSs, such as air cooling, liquid cooling, phase change materials, heat pipes, external preheating, and internal preheating, discussing their advantages and disadvantages. Through comparative analyses of high-temperature cooling and low-temperature preheating, we highlight the research trends to inspire future researchers. According to the review of the literature, submerged liquid BTMS configurations show the greatest potential as a research focus to enhance thermal regulation in Li-ion batteries. In addition, there is considerable research potential in the innovation of air-based BTMSs, the optimization of liquid-based BTMSs, the coupling of heat pipes with PCMs, the integration of PCMs and liquid-cooled hybrid BTMSs, and the application of machine learning and topology optimization in BTMS design. The application of 3D printing in lithium-ion battery thermal management promises to enhance heat transfer efficiency and system adaptability through the design of innovative materials and structures, thereby improving the battery’s performance and safety. Full article
(This article belongs to the Special Issue Advanced Thermal Management Technologies and Heat Transfer)
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20 pages, 3331 KiB  
Article
Innovative Design of Solid-State Hydrogen Storage and Proton Exchange Membrane Fuel Cell Coupling System with Enhanced Cold Start Control Strategy
by Jianhua Gao, Su Zhou, Lei Fan, Gang Zhang, Yongyuan Jiang, Wei Shen and Shuang Zhai
Appl. Sci. 2024, 14(10), 4068; https://doi.org/10.3390/app14104068 - 10 May 2024
Cited by 3 | Viewed by 2179
Abstract
This paper presents an innovative thermally coupled system architecture with a parallel coolant-heated metal hydride tank (MHT) designed to satisfy the hydrogen supply requirements of proton exchange membrane fuel cell s(PEMFCs). This design solves a problem by revolutionising the cold start capability of [...] Read more.
This paper presents an innovative thermally coupled system architecture with a parallel coolant-heated metal hydride tank (MHT) designed to satisfy the hydrogen supply requirements of proton exchange membrane fuel cell s(PEMFCs). This design solves a problem by revolutionising the cold start capability of PEMFCs at low temperatures. During the design process, LaNi5 was selected as the hydrogen storage material, with thermodynamic and kinetic properties matching the PEMFC operating conditions. Afterwards, the MHT and thermal management subsystem were customised to integrate with the 70 kW PEMFC system to ensure optimal performance. Given the limitations of conventional high-pressure gaseous hydrogen storage for cold starting, this paper provides insights into the challenges faced by the PEMFC-MH system and proposes an innovative cold start methodology that combines internal self-heating and externally assisted preheating techniques, aiming to optimise cold start time, energy consumption, and hydrogen utilisation. The results show that the PEMFC-MH system utilises the heat generated during hydrogen absorption by the MHT to preheat the PEMFC stack, and the cold start time is only 101 s, which is 59.3% shorter compared to that of the conventional method. Meanwhile, the cold start energy consumption is reduced by 62.4%, achieving a significant improvement in energy efficiency. In conclusion, this paper presents a PEMFC-MH system design that achieves significant progress in terms of time saving, energy consumption, and hydrogen utilisation. Full article
(This article belongs to the Topic Energy Storage and Conversion Systems, 2nd Edition)
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16 pages, 5703 KiB  
Article
Numerical Simulation of Squeeze-Casting SiC3D/Al Ceramic Matrix Composites
by Yangwei Wang, Fangzhou Zhang, Sijia Feng, Jiawei Bao, Yanni Gong, Chunyuan Yuan and Denghui Zhao
Metals 2024, 14(2), 172; https://doi.org/10.3390/met14020172 - 30 Jan 2024
Cited by 2 | Viewed by 1754
Abstract
In this study, the filling and solidification processes of squeeze-casting SiC3D/Al composites were analyzed by the ProCAST simulation software (ver. 2018.0). A practical squeeze-casting experiment was conducted to verify the accuracy of the simulation results. A series of orthogonal experiments were [...] Read more.
In this study, the filling and solidification processes of squeeze-casting SiC3D/Al composites were analyzed by the ProCAST simulation software (ver. 2018.0). A practical squeeze-casting experiment was conducted to verify the accuracy of the simulation results. A series of orthogonal experiments were conducted on the initial preheating temperature of various components to identify the optimal parameters in order to achieve better porosity and stress concentration values. According to the results and analyses, the preheating temperature of the mold was the most important determining factor. Under a pouring temperature of 700 °C, mold preheating temperature of 200 °C, and SiC skeleton preheating temperature of 600 °C, the maximum principal stress at the bottom of the products was decreased by about 41.9%, and the shrinkage volume inside the composite was decreased about by about 61.6%. Thus, by adjusting the initial preheating temperature of various components, the squeeze-casting SiC3D/Al composites could achieve better performance and fewer internal defects. Full article
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19 pages, 3875 KiB  
Article
Drying Kinetics and Mass Transfer Characteristics of Walnut under Hot Air Drying
by Xiaolan Man, Long Li, Xiuwen Fan, Hong Zhang, Haipeng Lan, Yurong Tang and Yongcheng Zhang
Agriculture 2024, 14(2), 182; https://doi.org/10.3390/agriculture14020182 - 25 Jan 2024
Cited by 8 | Viewed by 1937
Abstract
This study was conducted to investigate the drying kinetics and internal and external mass transfer characteristics of walnuts for an understanding of the drying mechanism. The drying characteristics, mass transfer characteristics, and color of walnut during hot air drying (HAD) were [...] Read more.
This study was conducted to investigate the drying kinetics and internal and external mass transfer characteristics of walnuts for an understanding of the drying mechanism. The drying characteristics, mass transfer characteristics, and color of walnut during hot air drying (HAD) were investigated under different initial moisture content (IMC) (0.35, 0.39, and 0.43 g water/g wet mass) and drying temperatures (50, 60, 70, and 80 °C). The results indicated that the IMC and drying temperature both have significant effects on the drying process of walnut, showing the higher the IMC, the longer the preheating time, the smaller the effective moisture diffusivity (Deff) and mass transfer coefficient (hm), and the longer the drying time, but reverse results for drying temperature. The values of Deff and hm for walnut ranged from 4.94 × 10−10 to 1.44 × 10−9 m2/s and 1.24 × 10−7 to 3.90 × 10−7 m/s, respectively. The values of activation energy for moisture diffusion and mass transfer ranged from 21.56 to 23.35 kJ/mol and 28.92 to 33.43 kJ/mol, respectively. Multivariate linear prediction models were also established for estimating the Deff and hm as a function of the HAD process parameters. The drying temperature has a greater effect on the walnut kernel lightness than the IMC. The Verma et al model could be used to describe the HAD process of the walnut. The findings contribute to the understanding of moisture transfer mechanisms in walnuts and have practical value for the evaluation and improvement of drying systems. Full article
(This article belongs to the Section Agricultural Product Quality and Safety)
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