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This paper investigated the impact of the distance of the heating unit from the body in a multi-layered winter clothing system on effective thermal insulation and heating efficiency.

To identify changes in the thermal insulation and heating efficiency of electrical heating in different layers inside a winter clothing ensemble, a series of thermal manikin tests was conducted. A multi-layered winter ensemble with and without activation of a heating unit was tested on the thermal manikin under two different ambient temperature conditions (10°C and -5°C).

Results show that the effective thermal insulation of test ensembles increased by 5-7% with the activation of the heating unit compared to that without the activation. The closer the heating unit to the body, the higher the effective thermal insulation was in both ambient temperature conditions. This trend was more significant at lower ambient temperature.

The results of this study indicate that providing electric heating next to the skin is the most effective in increasing effective thermal insulation and decreasing body heat loss in both ambient temperature (-5°C and 10°C). This trend was more remarkable in colder environment at -5°C of ambient temperature as evidenced by sharp decrease in heating efficiency and effective thermal insulation with an increase in distance between the manikin skin and heating unit at -5°C of ambient temperature compared to at 10°C of ambient temperature.

Based on the results, it is expected that proximity heating next to the skin, in cold environment, may reduce the weight and size of the battery for the heating unit because of the higher efficiency of electric heating and the potentially immediate perception of warmth supported by the greatest increase in effective thermal insulation, as well as the lowest heat loss that comes with activation of heating on the first layer in cold environment.

The finding of this study provides guidelines to sportswear designers, textile scientists, sports enthusiasts, and civilians who consider electric heating benefits for improved thermal comfort and safety in cold environments, especially in the areas of outdoor and winter sports and in military service. The results of this study indicate that providing electric heating next to the skin is the most effective in increasing effective thermal insulation and decreasing body heat loss in both ambient temperature (-5°C and 10°C).

The purpose of this paper is to develop a barrel heating system using induction heating instead of resistance heating. And, a working coil for the induction heating system was designed so that the barrel has uniform temperature distribution.

A coupling design combining the pitch of turns of working coil with the magnetic flux concentrators in the barrel induction heating system was developed to achieve uniform temperature distribution which was approximately the same as temperature uniformity obtained from that of resistance heating system.

In contrast to resistance heating method, induction heating is more efficient because the heating is directly applied on the work-piece. Its heating rate is higher than that of resistance heating method. However, the uneven temperature distribution in the barrel is the main disadvantage of the induction heating system. But, with proper design of adjusting the pitch of turns at the center of working coil and adding magnetic flux concentrators at areas with lower magnetic flux, the barrel heating system via induction can achieve temperature distribution uniformity.

Under proper design of working coil, the barrel heating system by induction method can achieve the same uniform temperature distribution as the barrel heated by resistance method, and could be practically used in an injection molding machine.

Summarises the evolution of underfloor heating in buildings. Examines the main types of underfloor heating systems in ground floors. Discusses the pros and cons of this method of heating buildings. Shows that with the introduction of flow‐applied screeds and plastic piping, as well as improved installation and control procedures, underfloor heating is making a comeback in a growing number of new‐build schemes in the UK. However, this study indicates that it will be many years before universal confidence in the system is achieved.

The purpose of this paper is to investigate the concept of “electrically conductive fabrics”. The primer applications that import electrical conductivity properties to textiles and clothing are summarized. Also the heated fabric panels produced by steel yarns are evaluated. Single and multi‐ply steel fabrics are applied to electrical current and their heating behaviors are observed and compared.

The integration of electronic components with textiles to create very smart structures is getting more and more attention in recent years. Most of the textile materials are electrical insulators. Hence, various types of fibers and fabrics having reasonably good electrical conductivity are required especially for electronically functional apparel products. The textile‐based materials being flexible and easily workable are the most preferred one in such cases. In this study, the steel yarns are placed in the fabric construction owing to their flexible characteristics. The heating panels used in this study are produced by conventional textile processes and applied to electrical current. For this purpose, an electronic circuit that contains textile‐based warming panels connected to a power supply, has been developed.

The heated steel fabric panels with different number of plies provide different heating degree intervals owing to the different resistance levels, Therefore, in the applications of textile‐based heating elements it is suggested that the electrical characterization of conductive materials should be examined and the materials that have the most appropriate electrical resistance characteristic must be applied. Furthermore, in the circuits used for heating function, the current amount depends on the electrical features of heating structures. Consequently, the pads with different plies have various efficient heating in point of time. It is recommended that the appropriate heating pad dimensions, ply or conductive yarn amounts and sufficient power supply conditions should be evaluated and chosen according to the desired heating level.

Electrically conductive stainless steel yarns are processed to form a heating panel that can be used within an electronic circuit as a warming mechanism.

Low flow bikini solar combisystems and high flow tank‐in‐tank solar combisystems have been studied theoretically. The aim of this paper is to study which of these two solar combisystem designs is suitable for different houses. The thermal performance of solar combisystems based on the two different heat storage types is compared.

The thermal performance of Low flow bikini solar combisystems and high flow tank‐in‐tank solar combisystems is calculated with the simulation program TRNSYS. Two different TRNSYS models based on measurements were developed and used.

Based on the calculations it is concluded that low flow solar combisystems based on bikini tanks are promising for low energy buildings, while solar combisystems based on tank‐in‐tank stores are attractive for the houses with medium heating demand and old houses with high heating demand.

Many different Solar Combisystem designs have been commercialized over the years. In the IEA‐SHC Task 26, twenty one solar combisystems have been described and analyzed. Maybe the mantle tank approach also for solar combisystems can be used with advantage? This might be possible if the solar heating system is based on a so‐called bikini tank. Therefore, the new developed solar combisystems based on bikini tanks is compared to the tank‐in‐tank solar combisystems to elucidate which one is suitable for three different houses with low energy heating demand, medium and high heating demand.

This paper aims to deal with different induction and conduction heating approaches to realize a tailored heating of round billets for hot forming processes. In particular, this work examines the limits in which tailor-made temperature profiles can be achieved in the billet. In this way, a flow stress distribution based on the temperature field in the material can be set in a targeted manner, which is decisive for forming processes.

For the heating of round billets by induction, the rotationally symmetric arrangement is used and a parameterized 2D finite element method model is created. The harmonic electromagnetic solution is coupled with the transient thermal solution. For heating by means of conduction, the same procedure is used only with the use of a 3D model.

First results have shown that both methods can achieve very good results for billets with small diameters (d < 30 mm). For larger diameters, an adapted control of the heating process is necessary to ensure through heating of the material. Further investigations are carried out.

Using tailored heating for forging billets, several forming steps can be achieved in one step. Among other things, higher energy efficiency and throughput rates can be achieved.

The peculiarity of the tailored heating approach is that, in contrast to inhomogeneous heating, where only partial areas are heated, the entire component is heated to the target.

The paper aims to reveal the relationship among energy efficiency, thermal comfort and thermal regulation of electrically heated footwear and to investigate influencing factors on the energy efficiency and thermal comfort.

A finite volume model was proposed to simulate the two-dimensional heat transfer in electrically heated footwear (EHF) under an extremely cold condition. The model domain consists of three-layer footwear materials, a heating pad, a sock material, an air gap and skin tissues. Model predictions were verified by experimental data from cold-contact exposure. Then the influencing factors on the energy efficiency and thermal comfort were investigated through parametric analysis.

The paper demonstrated that the skin temperature control (STC) mode provided superior thermal comfort compared to the heating pad temperature control (HPTC) mode. However, the energy efficiency for the HPTC mode with a heating temperature of 38 °C was 18% higher than the STC mode. The energy efficiency of EHF while reaching the state of thermal comfort was strongly determined by the arrangement and connection of heating elements, heating temperature, thickness and thermal conductivity of footwear materials.

The findings obtained in this paper can be used to engineer the EHF that provides optimal thermal comfort and energy efficiency in cold environments.

Thermal protection of a flange is critical for preventing tower icing and collapse of wind turbines (WTs) in extremely cold weather. This study aims to develop a novel thermal protection system for the WTs flanges using an electrical heat-tracing element.

A three-dimensional model and the Poly-Hexacore mesh structure are used, and the fluid-solid coupling method was validated and then deployed to analyze the heat transfer and convection process. Intra-volumetric heat sources are applied to represent the heat generated by the heating element, and the dynamic boundary conditions are considered. The steady temperature and temperature uniformity of the flange are the assessment criteria for the thermal protection performance of the heating element.

Enlarging the heating area and increasing the heating power improved the flange's temperature and temperature uniformity. A heating power of 4.9 kW was suitable for engineering applications with the lowest temperature nonuniformity. Compared with continuous heating, the increased temperature nonuniformity was buffered, and the electrical power consumption was reduced by half using pulse heating. Pulse heating time intervals of 1, 3 and 4 h were determined for the spring, autumn and winter, respectively.

The originality of this study is to propose a novel electrical heat-tracing thermal protection system for the WTs flanges. The effect of different arrangements, heating powers and heating strategies was studied, by which the theoretical basis is provided for a stable and long-term utilization of the WT flange.

This study aims to undertake a comprehensive examination of heat transfer by convection in porous systems with top and bottom walls insulated and differently heated vertical walls under a magnetic field. For a specific nanofluid, the study aims to bring out the effects of different segmental heating arrangements.

An existing in-house code based on the finite volume method has provided the numerical solution of the coupled nondimensional transport equations. Following a validation study, different explorations include the variations of Darcy–Rayleigh number (Ra_m = 10–10⁴), Darcy number (Da = 10^–5–10^–1) segmented arrangements of heaters of identical total length, porosity index (ε = 0.1–1) and aspect ratio of the cavity (AR = 0.25–2) under Hartmann number (Ha = 10–70) and volume fraction of φ = 0.1% for the nanoparticles. In the analysis, there are major roles of the streamlines, isotherms and heatlines on the vertical mid-plane of the cavity and the profiles of the flow velocity and temperature on the central line of the section.

The finding of a monotonic rise in the heat transfer rate with an increase in Ra_m from 10 to 10⁴ has prompted a further comparison of the rate at Ra_m equal to 10⁴ with the total length of the heaters kept constant in all the cases. With respect to uniform heating of one entire wall, the study reveals a significant advantage of 246% rate enhancement from two equal heater segments placed centrally on opposite walls. This rate has emerged higher by 82% and 249%, respectively, with both the segments placed at the top and one at the bottom and one at the top. An increase in the number of centrally arranged heaters on each wall from one to five has yielded 286% rate enhancement. Changes in the ratio of the cavity height-to-length from 1.0 to 0.2 and 2 cause the rate to decrease by 50% and increase by 21%, respectively.

Further research with additional parameters, geometries and configurations will consolidate the understanding. Experimental validation can complement the numerical simulations presented in this study.

This research contributes to the field by integrating segmented heating, magnetic fields and hybrid nanofluid in a porous flow domain, addressing existing research gaps. The findings provide valuable insights for enhancing thermal performance, and controlling heat transfer locally, and have implications for medical treatments, thermal management systems and related fields. The research opens up new possibilities for precise thermal management and offers directions for future investigations.

The present study provides a comprehensive review of the advancements in five active heating modes for cold-proof clothing as of 2021. It aims to evaluate the current state of research for each heating mode and identify their limitations. Further, the study provides insights into the optimization of intelligent temperature control algorithms and design considerations for intelligent cold-proof clothing.

This article presents a classification of active heating systems based on five different heating principles: electric heating system, solar heating system, phase-change material (PCM) heating system, chemical heating system and fluid/air heating system. The systems are analyzed and evaluated in terms of heating principle, research advancement, scientific challenges and application potential in the field of cold-proof clothing.

The rational utilization of active heating modes enhances the thermal efficiency of cold-proof clothing, resulting in enhanced cold-resistance and reduced volume and weight. Despite progress in the development of the five prevalent heating modes, particularly with regard to the improvement and advancement of heating materials, the current integration of heating systems with cold-proof clothing is limited to the torso and limbs, lacking consideration of the thermal physiological requirements of the human body. Additionally, the heating modes of each system tend to be uniform and lack differentiation to meet the varying cold protection needs of various body parts.

The effective application of multiple heating modes helps the human body to maintain a constant body temperature and thermal equilibrium in a cold environment. The research of heating mode is the basis for realizing the temperature control of cold-proof clothing and provides an effective guarantee for the future development of the intelligent algorithms for temperature control of non-uniform heating of body segments.

The integration of multiple heating modes ensures the maintenance of a constant body temperature and thermal balance for the wearer in cold environments. The research of heating modes forms the foundation for the temperature regulation of cold-proof clothing and lays the groundwork for the development of intelligent algorithms for non-uniform heating control of different body segments.

The present article systematically reviews five active heating modes suitable for use in cold-proof clothing and offers guidance for the selection of heating systems in future smart cold-proof clothing. Furthermore, the findings of this research provide a basis for future research on non-uniform heating modes that are aligned with the thermal physiological needs of the human body, thus contributing to the development of cold-proof clothing that is better suited to meet the thermal needs of the human body.