Heat Distribution Research Articles

Spatial and Temporal Distribution of Nanoflare Heating during Active Region Evolution

Abstract Nanoflares are believed to be key contributors to heating solar nonflaring active regions, though their individual detection remains challenging. This study uses a data-driven field-aligned hydrodynamic model to examine nanoflare properties throughout the lifecycle of active region (AR) 12758. We simulate coronal loop emissions, where each loop is heated by random nanoflares depending on the loop parameters derived from photospheric magnetograms observed by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager. Simulated X-ray flux and temperature can reproduce the temporal variations observed by the Chandrayaan-2/Solar X-ray Monitor. Our findings show that high-frequency nanoflares contribute to cool emissions across the AR, while low- and intermediate-frequency primarily contribute to hot emissions. During the emerging phase, energy deposition is dominated by low-frequency events. Post-emergence, energy is deposited by both low- and intermediate-frequency nanoflares, while as the AR ages, the contribution from intermediate- and high-frequency nanoflares increases. The spatial distribution of heating frequencies across the AR reveals a clear pattern: the core of the active region spends most of its time in a low-frequency heating state, the periphery is dominated by high-frequency heating, and the region between the core and periphery experiences intermediate-frequency heating.

Hydrogeological analysis of topography-driven groundwater flow in a low temperature geothermal aquifer system in the Julian Alps, Slovenia

Abstract Groundwater flow and heat distribution was investigated in the regional karstic-fissured aquifer-aquitard system near Lake Bled in the Slovenian, eastern Julian Alps. The area features thermal springs with temperatures of 19–23 °C which are exploited by abstraction wells. The occurrence of low-temperature geothermal systems, which are common in the Alps, are associated with specific hydrogeological conditions, such as vertical hydraulic connectivity between different geological formations, relatively large elevation differences along flow paths, and the concentrated upwelling of geothermal water to the surface. The occurrence of the low-temperature geothermal field is explained by the presence of a hydraulically conductive fault along with a regional groundwater flow pattern that supports deep groundwater circulation. Hydraulic measurements and temperature data were collected from springs and wells in the area to support the analysis of flow patterns, together with the construction of a basin-scale 2D numerical flow and heat transport simulation. The diverse topographic and geological conditions result in a multi-scale groundwater flow system. The discharge of thermal waters in the Lake Bled area is a consequence of the upwelling of deep groundwater induced by a combination of the ~ 650 m difference in hydraulic head and hydrogeological heterogeneity and anisotropy, related to faulting of the geological formations. In addition, individual flow subsystems were found to significantly affect the natural heat distribution and travel times within the basin-scale system. The study highlights the combination of a basin scale approach taking into consideration local to regional-scale heterogeneities and faults in order to better understand the hydrogeological behaviour of Alpine groundwater systems.

A Novel Non-Resonant Full-Bridge Multi-Output Topology for Domestic Induction Heating Applications

Induction heating technology plays a significant role in heating applications with its high efficiency, fast response, and precise control ability. Traditional resonant inverter-based systems face problems such as complexity, lack of flexibility, and low efficiency in multi-load situations. To overcome these issues, a new non-resonant full-bridge multiple-output inverter topology using silicon carbide (SiC) semiconductor devices is presented. While the system is simplified by eliminating resonant components, efficiency is increased thanks to SiC devices. In the study, a coil design methodology focusing on coil resistance and inductance is presented to optimize energy transfer and maximize system performance. Load-sensing and advanced frequency-modulation techniques are integrated to provide precise and independent power regulation in multi-loads. Thus, the efficiency of energy distribution and system robustness are increased. The proposed topology offers heating performance that provides homogeneous heat distribution. The developed prototype was proven to operate reliably with high efficiency under different load conditions and was suitably applied for domestic induction heating applications. An efficiency of 96.78% was achieved at a 50 kHz operating frequency and 2000 W power level.

Flue Gas Recirculation in Steam Boilers: A Comprehensive Assessment Strategy for Energy Optimization and Efficiency Enhancement

In modern steam boilers, flue gas recirculation (FGR) is generally adopted as a temperature control method for reheated steam. Some research suggests that FGR does not affect the thermal performance of steam boilers, while other studies report enhanced thermal performance. This investigation aims to enhance energy efficiency by using an iterative calculation approach to provide a thorough energy evaluation of a steam boiler with an integrated FGR system. The research applies thermodynamic and heat transfer principles to model combustion characteristics, radiative heat transfer in the furnace waterwall, and convective and inter-tube radiative heat transfer in the economizer, superheaters, and reheater. The model is validated using specifications from an existing power plant boiler and a parametric analysis to examine the effects of varying FGR rates on heat distribution and thermal performance at full and partial loads. The results show that radiative heat accounts for an average of 45% of the total heat supplied, with up to 10% in the heat recovery section. As the FGR rate increases, radiative heat in the heat recovery section decreases by 50%, while the convective heat transfer increases then drops. The model shows that the ideal FGR is bounded between 0.3 at 50% boiler load and 0.4 at full load. An analysis of the impact of FGR on the various parts of the boiler reveals that the economizer experiences the most significant net change in heat gain, followed by the reheater. The effect of gas recirculation on the economizer can be nearly twice as great as on the reheater, indicating that FGR has substantial influence on components beyond the reheater. The findings indicate that reducing excessive heat in the economizer and reheater can be accomplished under different load conditions by regulating the fuel consumption rate according to the analysis of the effects of FGR on radiative and convective heat transfer across various components.

Microwave-Assisted In-Situ Synthesis of Polyethersulfone–ZnO Nanocomposite Membranes for Dye Removal: Enhanced Antifouling, Self-Cleaning, and Antibacterial Properties

Microwave-assisted synthesis presents a promising method for enhancing the formation of nanocomposites due to its rapid heating and uniform energy distribution. In this study, we successfully fabricated polyethersulfone–zinc-oxide (PES-ZnO) nanocomposite membranes by exposing PES/ZnCl2/DMF dope solutions to microwave radiation. Before synthesizing the membranes, zinc-oxide nanoparticles (ZnO-NPs) were optimized in an organic phase using microwave radiation to ensure effective nanoparticle formation. The synthesis of ZnO-NPs in DMF solvent was validated through UV–Vis spectroscopy, X-ray diffraction (XRD), and Dynamic Light Scattering (DLS). We examined the surface morphology and roughness of the PES-ZnO membranes through Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Moreover, we assessed the membranes’ hydrophilicity, permeability, and physicochemical properties through contact-angle measurements, pure water flux tests, water uptake assessments, and porosity tests. Energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) verified the successful integration of ZnO nanoparticles (ZnO-NPs) into the membrane matrix. The results indicate that including ZnO-NPs significantly improves the membrane’s permeability and hydrophilicity. The nanocomposite membranes exhibited high dye rejection efficiency, with ZnO-NPs facilitating photocatalytic self-cleaning properties. Antibacterial tests also demonstrated a substantial inhibition of common bacteria, suggesting enhanced resistance to biofouling. This research highlights the potential of microwave-assisted PES-ZnO nanocomposite membranes as effective and sustainable solutions for wastewater treatment, offering scalable applications along with added benefits of antifouling, self-cleaning, and antibacterial properties.

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.

Numerical study of heat distribution in a disk-shaped evaporator of a loop heat pipe at steady-state operation mode

Numerical study of heat distribution in a disk-shaped evaporator of a loop heat pipe at steady-state operation mode

Two-dimensional steady-state thermal analytical model of permanent magnet linear motor in Cartesian coordinates

Purpose Compared with the time-consuming numerical method and the complex lumped parameter thermal network method to solve the steady-state heat distribution of the permanent magnet (PM) linear motor, there is no analytical method based on the thermal partial differential equations. This paper aims to propose a two-dimensional (2-D) analytical model for predicting the steady-state temperature distribution of PM linear motors to improve the prediction accuracy and speed up the calculation. Design/methodology/approach Based on the complex Fourier series theory and Cauchy’s product theorem, this paper presents for the first time a general analytical solution for 2-D temperature field in Cartesian coordinates. Then, by combining the electromagnetic field finite element model (FEM), the copper loss, iron loss and PM eddy current loss are used as the heat sources of the thermal analytical model. Finally, the solution to the temperature field is obtained by solving the system equations under boundary and interface conditions. Findings The analytical results are in good agreement with those from the thermal FEM, and the calculation speed is significantly faster than that of the thermal FEM. Originality/value The multilayer model proposed in this paper can consider heat conduction, convection and radiation. It is not only suitable for PM linear motors but also has significant application value for the thermal analysis of electromagnetic devices modeled in 2-D Cartesian coordinates.

Design and Fabrication of Dryer for Zeolite Synthesis: Engineering Solution for Enhanced Material Processing

The design and fabrication of the electric dryer from locally sourced materials represent a cutting-edge advancement in drying technology, harnessing the unique properties of Zeolite materials to enhance energy efficiency and performance. Zeolites are microporous, aluminosilicate minerals known for their high adsorption capacity and thermal stability. Drying is one operation required in Zeolite synthesis and as a developing Nation, there is need to invest in design and fabrication of dryers instead of relying on the traditional method of drying where the Zeolite are allowed to dry natural in open air. The Electric dryer is engineered to provide precise temperature and speed control, uniform heat distribution and efficient air circulation thereby enhancing drying efficiency, reducing operational costs and promoting local technology. The dryer consists of a mild steel chamber, heating element, fan, thermocouple, temperature and speed control system. The fabrication process involved machining, welding and assembly of the various components. The dryer performance was evaluated by drying Kaolin (a precursor for Zeolite synthesis) samples under a certain temperature and fan speed to obtain percentage reduction in moisture content to 20% from 60%. The temperature range of the dryer is 28 to 300 degrees Celsius, dimensions of the designed and fabricated dryer are Width of 0.2286m, Height of 0.3048m and Breadth/depth of 0.3048m, Volume of dryer is 0.0 , Insulation thickness is 0.04m. while area of dryer door is 0.110 . For panel dimension: Height is 0.254m, Width is 0.152m and area of panel is 0.0386 , Tray Dimension is 0.241m by 0.330m and area of tray 0.0795 . Standard Operating Procedure and maintenance of the electric dryer was also captured in this work. The regulation of the fan speed is a novel approach to our design. This innovation represents a significant leap in the development of energy-efficient dryer, promising enhanced performance and reduced environmental impact.

The Impact of Fluid Flow on Microbial Growth and Distribution in Food Processing Systems

This article examines the impact of fluid flow dynamics on microbial growth, distribution, and control within food processing systems. Fluid flows, specifically laminar and turbulent flows, significantly influence microbial behaviors, such as biofilm development and microbial adhesion. Laminar flow is highly conducive to biofilm formation and microbial attachment because the flow is smooth and steady. This smooth flow makes it much more difficult to sterilize the surface. Turbulent flow, however, due to its chaotic motion and the shear forces that are present, inhibits microbial growth because it disrupts attachment; however, it also has the potential to contaminate surfaces by dispersing microorganisms. Computational fluid dynamics (CFD) is highlighted as an essential component for food processors to predict fluid movement and enhance numerous fluid-dependent operations, including mixing, cooling, spray drying, and heat transfer. This analysis underscores the significance of fluid dynamics in controlling microbial hazards in food settings, and it discusses some interventions, such as antimicrobial surface treatments and properly designed equipment. Each process step from mixing to cooling, which influences heat transfer and microbial control by ensuring uniform heat distribution and optimizing heat removal, presents unique fluid flow requirements affecting microbial distribution, biofilm formation, and contamination control. Food processors can improve microbial management and enhance product safety by adjusting flow rates, types, and equipment configurations. This article helps provide an understanding of fluid–microbe interactions and offers actionable insights to advance food processing practices, ensuring higher standards of food safety and quality control.

DISTRIBUTION OF URBAN HEAT ISLAND INDEX IN THE SURABAYA, YOGYAKARTA, AND BANDUNG USING REMOTE SENSING

Climate change is a global issue as it drives global warming and heightens the impact of greenhouse gases. In the past decade, the Urban Heat Island (UHI) phenomenon has become a growing concern in major cities due to urbanization and development. This study aims to analyze the distribution and relationship between changes in Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI), and Normalized Difference Built-up Index (NDBI) with UHI changes in Surabaya, Yogyakarta, and Bandung, and propose mitigation strategies. The descriptive quantitative approach is used in the research to explain the calculated area and percentage of NDVI, NDBI, LST, and UHI. Geographic Information System (GIS) technology, specifically ArcGIS 10.8, was utilized to process Landsat imagery data from 1994 and 2024, enabling spatial analysis and visualization of urban heat distribution and land use changes. Simple correlation analysis was also carried out to examine the relationship between LST and NDVI, as well as LST and NDBI. The analysis shows that NDVI decreased, while NDBI, LST, and UHI increased over the 30 years in all three cities. LST and NDVI have a strong inverse relationship, where increasing LST correlates with decreasing NDVI. NDBI shows a positive relationship with LST, meaning more built-up areas lead to higher LST and UHI. Mitigation strategies include expanding green spaces, adopting green building technologies, and utilizing renewable energy.

Dynamic Simulation of Heat Distribution and Losses in Cement Kilns for Sustainable Energy Consumption in Cement Production

Sustainable energy consumption in cement production involves practises and strategies aimed at reducing energy use and minimising environmental impact. The efficiency of a cement kiln is dependent on the kiln design, fuel type, and operating temperature. In this study, a dynamic simulation analysis is used to investigate heat losses and distribution within kilns with the aim of improving energy efficiency in cement production. This study used Computational Fluid Dynamics (CFD) with Conjugate Heat Transfer, Turbulent Flow, and the Realisable k−ϵ turbulence model to simulate heat transfer within the refractory and wall systems of the kiln, evaluate the effectiveness of these systems in managing heat losses, and establish the relationship between the heat transfer coefficient (HTC) and the velocities of solid and gas phases. The simulation results indicate that a temperature gradient from the kiln’s interior to its exterior is highly dependent on the effectiveness of refractory lining in absorbing and reducing heat transfer to the outer walls. The results also confirm that different thermal profiles exist for clinker and fuel gases, with clinker temperatures consistently peaking at approximately 1450 °C, an essential condition for optimal cement-phase formation. The results also indicate that phase velocities significantly influence heat absorption and transfer. Lower velocities, such as 0.2 m/s, lead to increased heat absorption, but also elevate heat losses due to prolonged exposure. The relationship between the heat transfer coefficient (HTC) and the velocities of solid and gas phases also indicates that higher velocities improve HTC and enhance overall heat transfer efficiency, reducing energy demand.

Visualization microclimate scenarios of Classical Chinese Garden in Suzhou, China

The intensification of urbanization worldwide, particularly in China, has led to significant challenges in maintaining sustainable urban environments, primarily due to the Urban Heat Island (UHI) effect. This effect exacerbates urban thermal stress, leading to increased energy consumption, poor air quality, and heightened health risks. In response, urban green spaces are recognized for their role in ameliorating urban heat and enhancing environmental resilience. This paper has studied the microclimate regulation effects of three representative classical gardens in Suzhou—the Humble Administrator’s Garden, the Lingering Garden and the Canglang Pavilion. It aims to explore the specific impacts of water bodies, vegetation and architectural features on the air temperature and relative humidity within the gardens. With the help of Geographic Information System (GIS) technology and the Inverse Distance Weighted (IDW) spatial interpolation method, this study has analyzed the microclimate regulation mechanisms in the designs of these traditional gardens. The results show that water bodies and lush vegetation have significant effects on reducing temperature and increasing humidity, while the architectural structures and rocks have affected the distribution and retention of heat to some extent. These findings not only enrich our understanding of the role of the design principles of classical gardens in climate adaptability but also provide important theoretical basis and practical guidance for the design of modern urban parks and the planning of sustainable urban environments. In addition, the study highlights GIS-based spatial interpolation as a valuable tool for visualizing and optimizing thermal comfort in urban landscapes, providing insights for developing resilient urban green spaces.

Assessing the impact of greenery on urban heat using opportunistic drive-by sensing

The urban heat island (UHI) phenomenon is recognized as a main urban sustainability problem in the face of a changing climate, affecting human health, energy consumption, and other socio-economic considerations. The UHI can be mitigated by urban greenery, but it needs further investigation of detailed impacts across the urban landscape. The aim was to study UHI and model the relation to greenery in combination with urban grey structures, at a high spatiotemporal resolution across the urban landscape, in Stockholm. Temperature data was collected through opportunistic drive-by sensors on electric three-wheeled taxis. Data on greenview and skyview factors were used to inform on greenery and building density along the roads. During night and morning hours, the surface temperature was in general higher than air temperature, indicating that some densely built-up environments stored heat overnight. Hot zones were unevenly distributed throughout the city, while greenery had a cooling effect, especially when combined with skyview as an inverse measure of building density. Our results provide information on the spatiotemporal distribution of heat that can be used to inform efforts to use greenery for mitigating impacts of UHI on urban residents.

Thermal Regulation Methods Aimed to Elevate Photovoltaic Panel Performance: A Review

Commercially used solar modules convert about 14 to 24% of sunlight into electrical energy. The remaining energy is kept in the panels which is converted into heat energy and increases the panel temperature. However, the increase in temperature caused by this input reduces the power output of the solar panel, i.e. in crystalline silicon cells it is about 0.40%/°C. And the resulting thermal stress also reduces the panel life. Therefore, it would be a smart solution to dissipate the heat generated on the photovoltaic system by cooling the panels with various methods in order to reduce the solar panel temperature and increase the module performance. This paper presents a summary study to review the significant researches on improving performance of photovoltaic systems. Among these researches, there are studies aiming to reduce the high operating temperature seen on the solar cell surface and to balance the inhomogeneous heat distribution such as cooling of a PV panel with natural and forced liquid and air, heat pipe, phase change material and thermoelectric module. Besides these studies, researches aiming to make optimum use of sunlight by reducing reflection, pollution and photo-angular effects, which are parameters that have weakening effects on the electrical performance of solar cells, are reviewed as well.

Assessing Urban Heat Islands Using GIS and Remote Sensing for Sustainable Urban Planning in the Philippines

Abstract- Growing urbanization and a tropical climate intensify the known environmental challenges of urban heat islands (UHIs) in the Philippines. UHIs are formed by human activity, infrastructure, and decreased vegetation, resulting in elevated temperatures in urban areas compared to their rural surroundings. This tendency exacerbates energy consumption, air pollution, and health concerns, posing significant issues for urban planners and policymakers. Geographic Information Systems (GIS) and remote sensing technologies provide efficient methods for evaluating and reducing UHIs. GIS enables the merging and examination of geographical data, providing a comprehensive understanding of urban settings. Remote sensing uses thermal data from satellites to provide a comprehensive understanding of land surface temperatures and heat distribution patterns. In the Philippines, these technologies are essential for detecting areas with high temperatures, assessing the elements that contribute to this, and creating specific policies for sustainable urban development. By utilizing GIS and remote sensing, urban planners can strategically create geographically accurate green spaces, optimize construction materials, and apply cooling measures, ultimately fostering a healthier and more resilient urban environment. This paper shows the significant utilization of these technologies to facilitate data-driven decision-making, which is crucial for mitigating the detrimental impacts of UHIs. This research can guide environmental planners on how to utilize GIS and remote sensing for a more scientific approach as urban areas continue to grow and science-based sustainable urban planning becomes more and more apparent. Evaluating UHIs using GIS and remote sensing is an essential step in the development of habitable, sustainable, and climate-resilient cities in the Philippines.

Investigation of the Effects of Wafer-Baking Plates on Thermal Distribution, Wafer Thickness, and Wafer Color Distribution

Wafer-baking ovens are machines that bake liquid batter by heating the interconnected cast plates in a gas oven. The plates in contact with the wafer batter are generally made of the cast material. Although there are many studies on the contents in the recipes of wafer products and the effects of the additives included in the recipes on the quality of the wafer sheet, there are few studies on the effects of the material type of the wafer-baking plate on the baking process. In this study, the thermal distribution of two baking plates made of different materials (GG-25 gray cast iron and GJV-350 vermicular cast iron), their effects on the thickness of the wafer sheet, and their effects on the color distribution of the wafer sheet were investigated at different baking rates. The experiments were conducted in an industrial wafer-baking oven at two different production rates. As a result, it was observed that the GJV-350 vermicular casting plate provides a more homogeneous heat distribution, more stable wafer sheet thickness, and more homogeneous color distribution of the wafer sheet at a maximum production rate.

STUDI TERMAL PADA SEGMEN CETAKAN CROWN PADA MESIN CURING DALAM PROSES PRODUKSI BAN MOBIL DI PT. ELANG PERDANA TYRE INDUSTRY

The curing process is a stage in car tire molding carried out under high temperature and pressure. One of the key components in this process is the crown mold segment, which functions to shape the tread pattern on the tire. This study aims to analyze the heat distribution in the crown mold segment using Solidworks software, focusing on material specifications, heat distribution patterns, and simulation parameters affecting the results. The material used is Steel AISI 1020. The simulation results indicate an even heat distribution with an initial temperature of 453 K, convection ranging from 179.933°C to 179.967°C on the side area, and 179.916°C to 179.950°C on the tread pattern. Heat transfer rates were recorded as 96,323.28 W through conduction, 898.452 W through convection, and 2.56 W through radiation. Key parameters influencing the simulation include the initial material temperature (453 K), convection coefficient (10 W/(m²·K)), radiation emissivity (0.3), and ambient temperature (300 K).

Control of double-heater heating systems for the efficient energy supply in heat distribution networks

Control of double-heater heating systems for the efficient energy supply in heat distribution networks

Micro-Scale Urban Heat Island Analysis of Residential Areas in Central Jakarta Using UAV Thermal Imaging Data

Urban heat island (UHI) effects are a critical concern for densely populated tropical cities, where rapid urbanization exacerbates local temperature disparities. This study investigates the micro-scale heat distribution in residential zones of Central Jakarta using UAV thermal imaging data. Land surface temperature (LST) maps were generated to analyze thermal variations and their correlation with land use types such as impervious surfaces (e.g., asphalt and concrete) and vegetation. High-density zones exhibited significantly higher daytime temperatures, reaching up to 47°C, compared to vegetated areas, which maintained cooler temperatures around 32°C. Temporal analysis revealed prolonged nighttime heat retention in impervious areas, with residual temperatures exceeding 27°C, while vegetated zones cooled rapidly to below 20°C. These findings highlight the critical role of vegetation in mitigating UHI effects and emphasize the need for targeted urban planning strategies to reduce localized heat intensity in residential zones.