Risk Of Overheating Research Articles

Performance of sandwich type fire-resistant flexible composite phase change material PEE@EBF for battery thermal management and runaway protection

To mitigate the risks of overheating and thermal runaway in lithium-ion batteries, this study proposes a novel sandwich-type fire-resistant flexible composite phase change material (CPCM), referred to as PEE@EBF. The core material (PEE) was created by melt-blending paraffin wax (PW), expanded graphite (EG), and ethylene–vinyl acetate copolymer (EVA). The outer layer, a fire-resistant coating (EBF), was applied to the surface of PEE and consists of epoxy resin (EP), boron nitride (BN), and the composite flame retardant (CFR). Test results demonstrated that PEE@EBF maintained structural integrity, exhibiting no significant deformation or leakage after being heated at 80 °C for 5 h. PEE@EBF also displayed a high latent heat of 166.6 J/g, thermal conductivity of 0.8 W/(m∙K), and excellent electrical insulation properties. Furthermore, it achieved a UL94 V-0 flame retardant rating, with notable reductions in peak heat release rate (PHRR) and peak smoke production rate (PSPR) by 67.8 % and 81.8 %, respectively. During long-term cycling at 4C, the peak temperature (PT) and maximum temperature difference (MTD) of batteries in the module incorporating PEE@EBF were reduced by 11.8 °C and 4 °C, respectively, compared to natural convection cooling. In addition, the heat generated during the battery thermal runaway was efficiently absorbed and transferred by PEE@EBF, delaying the irreversible thermal runaway process by 633 s. This indicated that the sandwich-type PEE@EBF was suitable for thermal management and fire protection in lithium-ion batteries or energy storage devices.

AI-led study of dynamic changes in milk containing hybrid nanoparticles in an electromagnetically vibrated channel subjected to thermal oscillations and rapid pressure changes: Implications for dairy industry

Oscillating electromagnetic forces generated from a vibrated Riga plate have broad implications across various scientific and engineering domains. Artificial intelligence (AI) is applied to optimize precision and energy efficiency in pasteurization and sterilization by regulating the thermal and dynamic behavior of nanoparticle-infused milk under electromagnetic heating. The technique ensures accurate temperature control, minimizes the risk of overheating, and preserves the milk's nutritional and sensory qualities. It focuses on predicting the thermal and dynamic behaviors of milk infused with silver and zinc oxide nanoparticles in an electromagnetically vibrated channel experiencing thermal oscillations and rapid pressure changes. The research integrates complex physical phenomena such as radiant heat emission and Darcy drag forces, employing Darcy's model to delve into drag within porous media. Detailed mathematical and physical descriptions of milk flow dynamics are established, with solutions efficiently derived using the Laplace Transform (LT) method. The results, encompassing shear stress (SS) and rate of heat transfer (RHT) analyses, are detailed in tables and graphs. Findings indicate enhanced milk momentum with higher modified Hartmann number and reduced momentum with wider electrode spacing. Elevated oscillation frequencies of the left channel wall stabilize milk flow in both hybrid nano-milk (HNM) and nano-milk (NM). Larger Casson parameter improves SS, while higher radiation parameter reduces RHT. An AI-driven artificial neural network (ANN) is employed for precise estimations, achieving 98.022% accuracy in SS testing, 98.99% in cross-validation, and a flawless 100% accuracy for RHT. The research findings can be implemented to precisely control the mixing of milk and its physical features at a molecular level, enabling more even heat distribution and faster, more efficient pasteurization or homogenization processes.

Enhancing the Heat Dissipation Efficiency of Computing Units Within Autonomous Driving Systems and Electric Vehicles

With the rapid development of autonomous driving technology and electric vehicles, the demand for computing units in vehicles has surged, particularly for high-density computing related to artificial intelligence, sensor fusion, and real-time data processing. This increase has posed significant heat dissipation challenges for automotive electronic systems. Effective heat dissipation is essential for ensuring system stability, safety, and extending the lifespan of these systems. This study explores the thermal design of computing units in current autonomous driving systems and electric vehicles. The electronic components within the computing units generate significant heat, but due to environmental constraints, fans can not be used for internal cooling, as their operation can draw in dust from the environment, contaminating the internal electronic components. Therefore, computing units are often designed with a sealed structure, utilizing the thermal conductivity of metal casings to quickly dissipate internal heat sources. The results of this study show that comparing embedded cooling modules within the casing to commonly used thermal pads reveals that changing the materials of the cooling module can significantly enhance cooling performance, noticeably reducing the temperature of the internal electronic components and minimizing the risk of overheating. Additionally, this can improve the overall reliability and performance of the system, providing new ideas and application prospects for future automotive thermal design.

Thermal Fault-Tolerant Asymmetric Dual-Winding Motors in Integrated Electric Braking System for Autonomous Vehicles

A conventional dual-winding (DW) motor has two internal windings consisting of a master part and a slave part, each connected to a different electronic control unit (ECU) to realize a redundant system. However, existing DW motors have a problem related to heat generation in both the healthy mode and the faulty mode of the motor operation. In the healthy mode, unexpected overloads can cause both windings to burn out simultaneously due to equal heat distribution. If the current sensor fails to measure correctly, the motor may exceed the designed current density of 4.7 [Arms/mm2] under air-cooling conditions, further increasing burnout risk. External factors such as excessive load cycles or extreme heat conditions can further exacerbate this issue. In the faulty mode, the motor requires double the current to generate maximum torque, leading to rapid temperature increases and a high risk of overheating. To address these challenges, this paper proposes the design of a thermal fault-tolerant asymmetric dual-winding (ADW) motor, which improves heat management in both healthy and faulty modes for autonomous vehicles. A lumped-parameter thermal network (LPTN) with a piecewise stator-housing model (PSMs) was employed to evaluate the coil temperature during faulty operation. An optimal design approach, incorporating kriging modeling, Design of Experiments (DOE), and a genetic algorithm (GA), was also utilized. The results confirm that the proposed ADW motor design effectively reduces the risk of simultaneous burnout in the healthy mode and overheating in the faulty mode, offering a robust solution for autonomous vehicle applications.

Health risk assessment of residential overheating under the heat waves in Guangzhou

During extreme heatwave events, indoor overheating caused by power outages poses a significant threat to human health, especially for low-income groups exposed to hot and humid conditions for extended periods. However, currently, the definition and quantification standards for indoor overheating are not well-defined, and relying solely on thermal comfort indicators is insufficient to accurately assess the health risks associated with indoor overheating. This study proposes the use of maximum heat index (HImax) and heat index hazard hours when the heat index exceeds the caution level (HIHHCaution) to assess the health risk of indoor overheating. Taking various types of residential buildings in Guangzhou as examples, the study employs field surveys, simulation analysis, and statistical regression to analyze the impact of power outages during heatwaves on the indoor thermal environment and key human thermal physiological parameters, thereby establishing the basis for measuring indoor overheating and reference thresholds for assessing heat health risks. The results indicate that for young adults and the elderly, HIHHCaution exceeding 1174 °C·h and 850 °C·h respectively, or HImax nearing 55 °C, are likely to result in heat-related illnesses. In Guangzhou, most urban village housing with poor insulation cannot withstand the risk of power outages lasting more than a day during heatwaves, while old housing and commodity housing that meets the energy-efficiency standards of different periods still face varying degrees of indoor overheating risk. The findings enhance understanding of indoor overheating health risks and provide a scientific basis for strategies to improve living environments during heatwaves.

Evaluating Thermal Comfort and Overheating Risks in A Social Housing Prototype: As Built Versus Retrofit Scenarios

Climate change has highlighted the importance of thermal comfort and its health-related outcomes, particularly for the most vulnerable members of society living in social housing. Due to their vulnerable living conditions, low-income people are more exposed to negative outcomes of overheating and cold indoor temperatures in buildings. Previous studies suggest that there is a significant risk of overheating in retrofitted buildings both for the current and future weather scenarios. The UK government has introduced new building regulations to assess and limit the risk of overheating in new buildings; however, there is still a need to assess and improve conditions for existing and retrofitted properties. This study aims to evaluate the effect of retrofit strategies on thermal comfort and the risk of overheating in social housing under current and future climatic conditions. A typical case study building was simulated in DesignBuilder to assess thermal comfort conditions for upgraded building fabric to Part L of the UK building regulations and Passive House standards. The summer results were analyzed according to CIBSE TM59 while the Predicted Mean Vote index (PMV) was used for winter analysis. Findings revealed that the south-facing bedrooms are most exposed to overheating. Risk of overheating significantly increased for the future weather scenarios by up to 10 times while winter thermal comfort improved for the retrofitted scenarios.

Optimization study of a Z-type airflow cooling system of a lithium-ion battery pack

The present study aims to optimize the structural design of a Z-type flow lithium-ion battery pack with a forced air-cooling system known as BTMS (battery thermal management system). The main goal is to minimize Tmax (maximum temperature) and ΔTmax (maximum temperature difference) while ensuring an even airflow distribution within the battery module. The present study thoroughly investigates critical factors, such as the inlet air velocity, tapered inlet manifold, and the number of secondary outlets, to evaluate their impact on thermal performance and airflow uniformity within the battery module. Increasing the inlet air velocity from 3 to 4.5 m/s significantly improves the thermal cooling performance of the BTMS, resulting in a decrease of 4.57 °C (10.05%) in Tmax and 0.29 °C (9.79%) in ΔTmax compared to the original 3 m/s velocity. Further, the study assesses the significance of a tapered inlet manifold as a critical factor, revealing its substantial impact on cooling performance and temperature reductions in battery cells 3–9. It also facilitates a more uniform airflow distribution, decreasing the velocity difference between channel 9 and channel 1 from 3.32 to 2.50 m/s. Incorporating seven secondary outlets significantly improves the heat dissipation ability of the BTMS, resulting in a decrease of 0.894 °C (2.18%) in Tmax and 2.23 °C (72.84%) in ΔTmax compared to the configuration with 0 secondary outlets. By optimizing these parameters, the aim is to enhance BTMS's capabilities, improving LIB (lithium-ion battery) packs' performance and reliability. The optimized structural design parameters proposed in this study yield practical applications that extend beyond theoretical insights, impacting diverse fields reliant on lithium-ion battery technology. Through enhanced thermal management systems, applications in electric vehicles and portable electronics are poised to experience improved performance and longevity. Furthermore, these advancements inform the development of next-generation battery packs, promising reduced overheating risks and extended battery life. Such innovations are critical in energy storage systems for renewable energy applications and electric vehicle technology, facilitating faster charging times and increased driving range. Moreover, the implications extend to aerospace applications, ensuring the reliability of batteries in extreme environmental conditions.

Dynamic Thermal Rating in Diverse Climatic Conditions: Uncertainty Analysis and Fuzzy Logic Approach

Abstract: In recent times, there has been a significant rise in the need for electricity, a trend expected to continue. This surge in demand has resulted in transmission lines operating at much higher capacities, which in turn exposes them to increased thermal and mechanical stress, ultimately impacting the reliability of the transmission network. In this paper presents a comprehensive analysis of the static thermal rating (STR) and dynamic thermal rating (DTR) of power lines across varied climatic conditions. The study encompasses a thorough investigation into the thermal behavior of power lines during both summer and winter seasons over a 24-hour period. Through rigorous computational simulations and empirical data collection, the STR and DTR profiles are determined to assess the real-time capacity of power lines under changing environmental conditions. Furthermore, the research introduces a novel approach utilizing fuzzy logic to model the dynamic thermal rating (FDTR) based on the IEEE 738 standard, in regions characterized by diverse climatic patterns. By integrating fuzzy logic with meteorological data, the FDTR model offers enhanced accuracy in predicting the thermal performance of power lines, considering factors such as ambient temperature, wind speed, and solar radiation. The proposed methodology aims to provide utilities and grid operators with a reliable tool for optimizing power transmission capacity, mitigating the risk of overheating, and ensuring grid reliability in regions with complex and fluctuating weather conditions. This study contributes to the advancement of smart grid technology and facilitates efficient energy management in diverse climate zones

Fuzzy Logic-Based Dynamic Thermal Rating Assessment for Adaptive Grid Operations

Abstract: In recent times, there has been a notable increase in electricity demand, which is expected to continue rising. This uptick in demand has led to transmission lines operating at higher capacities, exposing them to greater thermal and mechanical stress and affecting the reliability of the transmission network. This paper presents an in-depth analysis of the static thermal rating (STR) and dynamic thermal rating (DTR) of power lines across various climatic conditions. The study investigates the thermal behavior of power lines during both summer and winter seasons over a 24-hour period. Through computational simulations and empirical data collection, the study determines the STR and DTR profiles to evaluate the real-time capacity of power lines under changing environmental conditions. Additionally, the research introduces a novel approach using fuzzy logic to model the dynamic thermal rating (FDTR) based on the IEEE 738 standard, particularly in regions with diverse climatic patterns. By integrating fuzzy logic with meteorological data, the FDTR model improves accuracy in predicting the thermal performance of power lines, considering factors like ambient temperature, wind speed, and solar radiation. This methodology aims to offer utilities and grid operators a reliable tool for optimizing power transmission capacity, reducing the risk of overheating, and ensuring grid reliability in areas with complex and fluctuating weather conditions. The study contributes to the advancement of smart grid technology and facilitates efficient energy management in diverse climate zones.

Integrating project management with advanced cooling solutions for data centers: A path to enhanced energy efficiency

Data centers play a crucial role in modern digital infrastructure, but their energy consumption and associated carbon footprint are significant concerns. Among the various energy-consuming components of data centers, cooling systems stand out as major contributors. This paper explores the integration of project management principles with advanced cooling solutions to enhance energy efficiency in data centers. By effectively managing projects and implementing innovative cooling technologies, data center operators can achieve significant reductions in energy consumption and operational costs. The integration of project management practices with advanced cooling solutions involves several key steps. First, project management methodologies such as Agile or Waterfall are applied to plan and execute the implementation of advanced cooling technologies. This includes assessing current cooling systems, identifying suitable advanced solutions, and developing a timeline for implementation. Next, advanced cooling solutions such as liquid cooling, containment systems, or free cooling are deployed to reduce the energy required for cooling data center equipment. One of the primary benefits of integrating project management with advanced cooling solutions is enhanced energy efficiency. Advanced cooling technologies can significantly reduce the energy consumed by data center cooling systems, leading to lower operational costs and a smaller carbon footprint. Additionally, the use of project management methodologies ensures that the implementation of these technologies is carried out efficiently and effectively. Furthermore, this integration can lead to improved data center performance and reliability. By optimizing cooling systems, data center operators can ensure that IT equipment operates within optimal temperature ranges, reducing the risk of overheating and downtime. Additionally, the implementation of advanced cooling solutions can future-proof data centers against increasing heat loads from high-density computing equipment. In conclusion, integrating project management with advanced cooling solutions offers a promising path to enhance energy efficiency in data centers. By adopting this approach, data center operators can achieve significant energy savings, reduce their environmental impact, and improve overall operational efficiency.

Failure analysis of steam superheater boiler tube made of ASTM T22 steel

This study investigates the failure of T22 grade steel boiler tube, as per ASTM A 213/A A213M standards, which experienced significant plastic deformation with a characteristic 'fish mouth' appearance. Analysis revealed an increase in outer diameter up to 18 percent, coupled with a reduction in wall thickness from 8.8 mm to around 3 mm at the rupture site. Microstructural examination of samples taken away from the rupture site revealed a structure composed of ferrite and partially decomposed bainite, attributed to prolonged annealing, along with fine spherical carbide precipitates. Samples from the rupture area displayed ferritic-bainitic structure without secondary carbide precipitates, indicating exceeded transformation temperatures. Additionally, increased hardness in the rupture area suggested transitions of overcooled austenite into ferrite and bainite. Thickened scale, particularly on the inner surface, heightened the risk of overheating. Based on these findings, it was concluded that the tube failure resulted from short-time overheating.

Hot Summers in Nordic Apartments: Exploring the Correlation between Outdoor Weather Conditions and Indoor Temperature

As the incidence of extended hot summers in the Nordic climate increases due to climate change, non-mechanically cooled apartments face high risks of overheating. Hence, this study aimed to investigate the temporal effects of heatwaves on indoor temperatures and examine the correlation between outdoor weather conditions and indoor temperature levels. A comprehensive field study was conducted across over 6000 apartments in the Helsinki region during the hot summer of 2021 and its heatwaves. Results indicated that nearly half of the apartments experienced indoor temperatures above 27 °C for over 7 consecutive days. It was found that an outdoor daily average temperature of 19 °C could cause indoor daily average temperatures higher than 27 °C. Further, the study revealed a strong correlation between indoor temperatures and outdoor 5-day moving average temperature, allowing occupants time to take preventative measures. Additionally, a linear relationship was found between the indoor average temperature, the outdoor 5-day moving average temperature, and the 7-day moving average solar radiation. The strength of the correlation and the magnitude of the effects of outdoor temperature and solar radiation varied depending on the duration of heatwaves. This highlights the importance of considering heatwaves in the design and renovation of residential buildings in the Nordic climate.

Recent Advances in Thermal Management Strategies for Lithium-Ion Batteries: A Comprehensive Review

Effective thermal management is essential for ensuring the safety, performance, and longevity of lithium-ion batteries across diverse applications, from electric vehicles to energy storage systems. This paper presents a thorough review of thermal management strategies, emphasizing recent advancements and future prospects. The analysis begins with an evaluation of industry-standard practices and their limitations, followed by a detailed examination of single-phase and multi-phase cooling approaches. Successful implementations and challenges are discussed through relevant examples. The exploration extends to innovative materials and structures that augment thermal efficiency, along with advanced sensors and thermal control systems for real-time monitoring. The paper addresses strategies for mitigating the risks of overheating and propagation. Furthermore, it highlights the significance of advanced models and numerical simulations in comprehending long-term thermal degradation. The integration of machine learning algorithms is explored to enhance precision in detecting and predicting thermal issues. The review concludes with an analysis of challenges and solutions in thermal management under extreme conditions, including ultra-fast charging and low temperatures. In summary, this comprehensive review offers insights into current and future strategies for lithium-ion battery thermal management, with a dedicated focus on improving the safety, performance, and durability of these vital energy sources.

What Drives House Prices in Europe?

AbstractBoom‐and‐bust cycles in the housing market pose a threat to macroeconomic and financial stability, thus calling for a timely assessment of imbalances. This work sheds light on the drivers of house price dynamics in some euro area economies, investigating the risks of overheating. We show that an Error‐Correction‐Model (ECM) featuring a long‐run relationship between house prices and income and short‐run effects of interest rates and housing supply fits the data well in most cases. We then propose a novel model‐based misalignment indicator and find that extrapolative house price expectations play an important role in the build‐up of speculative bubbles.

Integration of Active Clothing with a Personal Cooling System within the NGIoT Architecture for the Improved Comfort of Construction Workers

Intense physical activity and high ambient temperature cause construction workers to be exposed to an increased risk of overheating, especially in the summer season. Personal cooling systems have great potential to support workers’ thermoregulation and reduce this risk. In particular, solutions based on the thermoelectric effect can provide high cooling effectiveness and ergonomics at the same time. In this paper, a newly developed active clothing solution with flexible thermoelectric modules intended for outdoor activities is presented. The active clothing was subjected to utility tests on a treadmill under laboratory conditions with the participation of potential end users. A comparison of results from cooled and uncooled places indicated a reduction in local skin temperature of as much as 2.7 °C. Moreover, a gradual decrease in temperature in the uncooled place during the experiment was observed. Based on the positive results from this evaluation, the personal cooling system was integrated into active clothing within the ASSIST-IoT NGIoT reference architecture. This allows contextual and personalized adjustment of the cooling power to be provided using AI techniques and, additionally, by using data from a weather station and a smartwatch. Training procedures and models for the AI system are proposed, with special attention paid to the privacy aspect.

Impact assessment of climate change on naturally ventilated residential buildings in Lebanon — Overheating risk under future climate scenarios

In light of current climate change and global warming, indoor overheating poses a significant risk. Buildings in the Mediterranean climate heavily rely on natural ventilation to maintain acceptable indoor thermal conditions. This reliance poses an increased risk to built environments in this region, particularly those occupied by low-income populations who cannot afford conditioning systems. This study assesses the thermal performance of typical residential buildings in Lebanon in response to future climate change, considering various emission scenarios and climate zones. The study uses morphed future weather data and dynamic building simulations to assess indoor overheating and the potential for natural ventilation to establish comfortable indoor conditions. Findings indicate that indoor overheating occurrences in naturally ventilated apartments are expected to increase in both frequency and intensity in the future, across different emission scenarios, varying by climate. The risk of overheating was highest in inland region, followed by coastal then mountain regions. Regarding natural ventilation comfort hours, coastal climates saw a significant decrease (40% to 26% in the worst case), inland climates witnessed a slight reduction (27% to 23% in the worst case), and mountain climates observed a marginal increase (1% to 3%), accompanied by an increased risk of overheating during peak periods.

Improved cooling of photovoltaic panels by natural convection flow in a channel with adiabatic extensions.

In hot dry regions, photovoltaic modules are exposed to excessive temperatures, which leads to a drop in performance and the risk of overheating. The present numerical study aims to evaluate the natural air cooling of PV modules by an inclined chimney mounted at the back. The basic equations were solved using the finite volume method. The validity of the model is verified by comparison with the data available in the literature. Thermal and dynamic flow patterns are analyzed for a variety of parameters: Rayleigh numbers from 102 to 106, PV panel tilt angle from 15° to 90°, and channel aspect ratios from 1/20 to 1/5. A critical aspect ratio has been determined to minimize overheating of the PV module. According to the computational results, the tilt angle and modified Rayleigh number increase the mass flow rate and mean Nusselt number. The overheating zone with maximum temperatures is located in the upper part of the photovoltaic panel. The addition of an extension to both channel's inlet and outlet was found to improve the cooling of the photovoltaic panels; however, only the extensions downstream of the channel are truly effective. The critical lengths at which channel performance improves significantly were identified by examining the impact of longer extensions on channel performance. Increasing the extension length from 0 to 3H improves the mass flow rate by 65%, the average Nusselt number by 13.4%, and leads to an 11% decrease in maximum temperature when Ra* = 106. This cooling technique is particularly promising for hot dry regions where water is scarce.

Power Distribution System Planning for Mitigating Overheating Risk Inequity

Power Distribution System Planning for Mitigating Overheating Risk Inequity

Comparing overheating risk and mitigation strategies for two Canadian schools by using building simulation calibrated with measured data

This paper compares the indoor overheating risk of two schools by considering the effect of selected building parameters, under extreme current and future climates, and proposes mitigation strategies. The indoor air temperature measurements were conducted in seven classrooms in two schools constructed in 1960 and 1990. These measurements are used to calibrate the building simulation models of these schools. The study's results show that, in the current extreme year, classrooms on upper floors with larger window-wall ratios WWR (60%) and lower thermal building envelope properties are at a higher risk of overheating. Conversely, in classrooms located on lower floors, or featuring a small WWR (10%), or better thermal properties, no other Climate-resilient measures are needed. Under extreme future years the external roller blind shading, night cooling, and cool roof measures will be necessary for both schools, particularly for last-floor classrooms with south orientation and a 60% WWR in 1960 building.

Smiles reimagined: The transformative power of overlay complete dentures in prosthodontic rehabilitation of ectodermal dysplasia patient

Ectodermal dysplasias (EDs) encompass a diverse set of conditions characterized by developmental abnormalities affecting ectodermal tissues. Hypohidrotic ectodermal dysplasia is a congenital syndrome marked by features such as sparse, delicate hair, skin and nail anomalies, reduced sweating capacity (attributed to a deficiency in sweat glands, resulting in sweat-related issues), and underdeveloped or missing teeth (partial or complete absence of primary and/or permanent dentition). In most instances, individuals with EDA can expect a typical lifespan and exhibit normal cognitive abilities. Nonetheless, the absence of sweat glands poses a risk of overheating, potentially leading to brain damage or even fatality in infancy if not promptly recognized. Therefore, early diagnosis holds significant importance. This case report presents a documented instance of ectodermal dysplasia, complemented by a comprehensive literature review.