Electric Heating Research Articles

Effects of difference in heating sources on ammonia reactivity: Possibility for photolysis-assisted ammonia combustion

Ammonia (NH3) reactivity in a micro flow reactor with a controlled temperature profile (MFR) is reexamined through species measurements utilizing two heating sources in the MFR: an H2/air flat flame and an electric heater. The maximum wall temperatures (Tw,max) formed in the reactor vary in a range of Tw,max = 1100–1400 K. A stoichiometric NH3/air mixture is tested, and exhaust NH3 is detected by a quadrupole mass spectrometer (QMS). Unexpectedly, NH3 is completely consumed at temperatures at least 100 K lower in the H2/air flat flame case compared to the electric furnace case, despite nearly identical conditions of a MFR characteristic residence time estimated by the wall temperature profiles and the convective flow velocity. Considering the non-thermal characteristics of the two heating sources that the H2/air flat flame emits ultraviolet light, whereas infrared light as thermal radiation is emitted within the electric furnace, the possibility of NH3 photolysis in the H2/air flat flame case is discussed based on literature regarding emissions from the H2/air flames, the transmittance of the quartz tube, and the photodissociation of NH3 in the ultraviolet region. When ultraviolet light emitted from the H2/air flat flame passes through the quartz tube and decomposes NH3 into NH2 and H radicals, these produced radicals enhance the growth of OH radicals, resulting in increased NH3 reactivity. These findings suggest the possibility of photolysis-assisted ammonia combustion, which could be an additional method to overcome the low reactivity of NH3.

A hierarchical framework for integration of smart buildings in fully-renewable multi-microgrids and distribution systems: Towards more sustainable societies

Using smart buildings would be a crucial step towards sustainability. Although in the literature, some research effort has focused on integration of smart buildings into power systems; the integration of fully-renewable smart buildings into fully-renewable microgrids and distribution systems has not been addressed before. In this paper, a tri-level hierarchical stochastic framework is developed for the integration of fully renewable smart buildings in fully renewable multi-microgrids (MGs) and distribution systems. The studied smart buildings have electric water heater, air conditioner, PV and battery. In the first level, the model of each smart building is separately solved to find optimal schedule of its resources and the desired electricity exchange with its corresponding MG. In the second level, each MG solves its operational planning model, considering its transactions with the connected smart buildings and finally, in the third level, distribution system operator solves its operational planning model, accepting the electricity exchange requests taken from all MGs. The proposed methodology is applied to a 69-bus 100 % renewable distribution system with 4 100 % renewable microgrids, integrated with 100 % renewable smart buildings. The results confirm the efficacy of the proposed methodology for the integration of 100 % renewable smart buildings in 100 % renewable multi-MGs. The results testify that that building-to-grid (B2G) capability decreases the operation cost of all smart buildings; the average decrease in operation cost of buildings, caused by B2G, is 38 %. The results on the studied case indicate that that the impact of batteries on operation cost of smart buildings is marginal. The results also show that the higher threshold of comfort index in smart buildings, results in their higher operation cost. The results of this research may be helpful for both smart building operators and power system operators. This research is in line with the global energy transition and decarbonisation targets as the considered smart buildings, microgrids and distribution system are fully renewable.

Ice source heat pump system for energy supply via gas pipelines – Part1: Performance analysis in residential units

This study evaluates the performance of heat pumps using water or ice as the heat source, with energy transferred via repurposed gas delivery pipes. The proposed system offers significant benefits for urban energy networks, particularly in densely populated areas. The article is divided into two main sections: the first compares the thermal efficiency of the proposed system for residential heating against similar heat pumps. The second section examines the implementation, energy transfer capacity, and water requirements of using a gas pipeline network. The study models various heating systems, including electric-resistance, air-source, water-source, ground-source, and ice-source heat pumps, in Nottingham throughout the year. The results show that switching from gas to heat pumps significantly increases electricity demand, especially during peak periods. Specifically, electric-resistance heating, air-source, water-source, and ice-source heat pumps increase peak electricity consumption by factors of 7.5, 3.2, 2.5, and 2.7, respectively, compared to a gas boiler. Additionally, electricity consumption exceeds the current peak for 89 %, 47 %, 35 %, and 39 % of the hours in the year for each respective system. These findings emphasize the proposed system's role in managing peak electricity demand and enhancing generation and transmission capacity post-natural gas phase-out.

Reproduction of decarburization caused by overheating in fire tube boiler material

One of the non-destructive testing methods for analysing fire tubes is the replica technique. This technique allows the investigation of microstructure, cracking, and high-temperature creep under operational circumstances without the cutting of the components. A cellulose-acetate foil was used to make a copy from the topography of the surface, which was suitable for microscopic analysis. In this paper, decarburization was generated in P355N fire tube material. The aim of the reproduction was to investigate the effect of overheating in boilers. The decarburization of the fire tube was made at different temperatures (300 – 900 °C) in an electric heating furnace. General deterioration and decarbonization began at 700 °C. A preliminary step of the decarburization was the transformation of the pearlite, which can be easily detected by scanning electron microscope. Grain growth could not be observed, and the particle size was unrelated to the thickness of the decarbonized layer.

Flow assurance of waxy crude oil through thermal methods using nichrome wire and ultrasonic waves effects – Experimental investigation

When crude oil transportation stops for a certain period, the low temperature causes sufficient wax crystallization inside pipelines. During the crystallization, pipelines are exposed to a decrease in the inner diameter of the pipe, which leads to clogging and an increase in pressure drop. The higher pressure drop may require a huge pumping force to break the wax crystals and start the flow, increasing the level of risks and costs. Recently, many thermal and non-thermal methods have been used to alleviate wax deposition, such as surfactants, electric heating, and chemicals. In this study, flow assurance of heavy crude oil was investigated through pipelines using ultrasonic waves, nichrome wires, and combined methods. It includes conducting an experimental investigation on the ability of applying the ultrasonic effect and nichrome wires to improve the transportation performances of waxy crude oil through pipelines in a safe and environmentally friendly manner at the lowest costs while maintaining the characteristics of crude oil at high levels. The cooling rate was also studied at surrounding temperatures close to 30°C, 15°C, and 5°C. An experimental setup was developed to study the efficiency of the combined method in heating the pipeline. It was observed that the combined method was found effective in heating pipelines to higher temperatures in a shorter time. When the surrounding temperature was 30 °C, the combined method was able to raise the temperature of the crude oil to 80 °C in just 9.96 min, while the nichrome wires took 25 min to raise the temperature to 73 °C. As for the ultrasonic, it took 28 min to bring the temperature to 65.6 °C. It has also been proven that the highest cooling rate occurs at the walls of the pipeline. Therefore, the deposition of wax begins on the walls first and then moves successively to the middle.

Mussel-inspired adhesion for layer-by-layer assembly towards multi-functional electrically conductive cotton fabric

Layer-by-layer (LBL) assembly has been widely utilized for constructing functional coatings to fabricate versatile materials. However, challenges arise when the assembly building blocks are electrically neutral. To address this issue, we report the use of mussel-inspired adhesion as a unique driving force for LBL assembly to fabricate electrically conductive cotton fabric (ECCF) with carbon nanotubes & graphene as conductive materials and poly(vinyl alcohol-graft-3,4-dihydroxybenzyl acetal) (PVD) as a mussel-inspired adhesive. The robust adhesion provided by PVD endowed the ECCF with excellent stability against sandpaper friction, tape peeling, and water washing. The use of the ECCF in some advanced application such as strain sensing, temperature sensing, and electric heating was studied in detail. The ECCF exhibited fast response and remarkable sensitivity in strain sensing, enabling real-time detection of various human motions such as bending, twisting, and swallowing. In temperature sensing, the ECCF exhibited a negative temperature coefficient effect and offered a linear response within the temperature range of 30–100 °C. In addition, the ECCF demonstrated exceptional electric heating performance, leading to potential use in outdoor insulation and thermal rehabilitation therapy. This innovative application of mussel-inspired adhesion in LBL assembly not only paves the way for advanced smart fabrics but also enhances functionality.

Radiation model and thermal characteristics of OLED glass substrate using electric heating tube

Glass substrate (GS) heating is a fundamental but significant technology for organic light emitting diode (OLED), which is critical to OLED displaying quality and efficiency. A rapid and reliable theoretical model is intensely demanded to guide practical system design, simulation analysis and experimental research for GS heating, but present radiative models are improper or inconvenient. Therefore, this paper establishes a new and direct calculation model with the addition of correctional coefficient 0.5 to blackbody radiation power of electric heating tube (EHT) and the proposal of comprehensive angle coefficient X, which can solve single and multi-source radiation problems theoretically. The simulation and experiment are both conducted for comparison analysis. The temperature errors of theory and simulation for multi EHTs are all within 1 % when compared with experimental results, which well validates the reliability and accuracy of theoretical and simulation models. Large EHT radius r, small distance L between EHT and GS, and suitable EHT number n are suggested, which benefits to the improvement of radiation heating and temperature uniformity of GS. It is hoped that this study can provide a useful tool on thermal radiation analysis and also a valuable promotion for practical OLED heating technology.

Efficient interfacial solar evaporation using a novel carbonized foam as photo-thermal converter

Recent research shows that one of the effective and green methods to reduce freshwater scarcity is interfacial solar evaporation. This method does not require energy consumption. One of the important challenges that should be taken into consideration in interfacial solar evaporator systems is the fabrication of solar absorbers with easy, environmentally friendly, cost-effective, efficient and scalable methods. Herein, a carbonized melamine foam (CMF) fabricated via a one-step, fast, low-cost and easy method for solar desalination. The CMF is fabricated by an electrical heat gun within a few minutes and is characterized by various techniques. The prepared CMF as a black foam shows excellent properties for solar desalination such as superhydrophilicity, high light absorption, high water transportation rate, good photo-thermal conversion, high rate of water evaporation and salt resistance. The prepared CMF shows repeatable performance in solar evaporation at consecutive evaporation cycles with solar evaporation rate of 3 kg m−2h−1 and high solar thermal conversion efficiency of 90 % under 1000 W m−2 illumination.

Design and performance research on metal-sprayed electrical heating films for aircraft wing anti-icing

Abstract Composite material, supercritical aircraft wings, and multi-electrical technology represent the future development trend of civil aircraft. However, domestically, the use of electrical heating for anti-icing on civil aircraft made of composite materials has not yet been implemented. In this study, focusing on the anti-icing technology of a specific aircraft wing leading edge, the article initially designs a metal thermal spraying circuit based on the thermal load distribution on the surface of the anti-icing area. Next, the research explores the resistive properties of the electrical heating film on the composite material wing leading edge, examining how the porosity and oxide content of the coating affect its resistivity. Finally, the metal thermal spray test is completed on the leading edge of the composite material aircraft wing. The test results indicate that the adherence and deposition rate of the coating on the leading edge of the aircraft wing are reliable. The resistivity of the heating film meets the performance specifications. The article develops an integrated metal thermal spray control method based on high-curvature composite materials, resulting in an electrical heating film with excellent shape adaptability, varying power density, and strong bonding, providing support for the domestic advancement of wing electrical heating anti-icing technology.

Energy flow tracking of integrated energy system with electric thermal storage boiler

Abstract With the complexity and diversification of the integrated energy system, accurate optimization of resource allocation and scheduling has become the focus of research. This paper studies the energy flow tracking technology of the heat-electric integrated energy system with an electric thermal storage boiler. The modeling of the electric thermal storage boiler and the application of the energy flow tracking technology not only improves the flexibility and stability of the system but also realizes the comprehensive monitoring and analysis of the electric energy and heat energy flow in the system. Finally, the energy flow tracking technology is used to reveal the flow path and distribution of energy in the system through the example of the integrated energy system. It also shows the flexible energy and space-time transfer characteristics of the electric thermal storage boiler in the electrothermal integrated energy system.

Determination of the coefficient of thermal effusivity ε for a semi-confined rod

The article provides methods and formulas for calculating the coefficient of thermal effusivity ε (coefficient of heat accumulation) of solid bodies using known solutions of direct heat conduction problem. The work describes a method by which the final formulas are simplified to algebraic equations using the relative temperature θM of heating semi-confined rod from the end. The temperature Tc at the beginning of the rod is measured — x0 and time — τ0 from the start of heating. For calculation, the amount of heat Q accumulated during heating by a heater with a constant temperature at the end of the rod is used for the entire heating time. The technique is physically implemented during the experiment by bringing the ends of two semi-confined rods into contact. A flat, low-inertia electric heater is placed between the rods. The amount of heat ∆Q used in the calculations is half of the total heat of the heater for the entire heating time.

Influence of heating elements layout on temperature uniformity in a large size heat treatment furnace

Computational Fluid Dynamics simulations were used to optimize heating elements placement on the walls of a large size electrical heat treatment furnace in order to reduce temperature gradients within the furnace and uneven temperatures on different faces of the blocks which could result in variabilities in final mechanical properties. Initial evaluations of different layouts highlighted the effectiveness of equipping two side walls. Subsequently, an optimal percentage of side wall coverage was identified through simulations and multi-objective evolutionary optimization. Genetic and pareto search algorithms yielded 10 % and 14.2 % as optimum values, respectively. Implementing an optimal coverage demonstrated significant reductions in surface temperature non-uniformity, surface-to-center temperature differential, and temperature differences between loaded blocks. These improvements suggest a potential for enhanced uniformity in mechanical properties across a batch of products. This approach presents a promising strategy for obtaining consistent and efficient heat treatment cycles in industrial heat treatment furnaces resulting in energy saving and improved product quality.

Evaluation of Heating Pad using Electrical Heating Element for Flexitank Transportation Application

Liquid transportation is accomplished in various ways, including the use of tankers and containers. Recently, most liquid shipments have utilized Flexitank as liquid containers, where steam heating is employed to melt frozen cargo liquids. However, due to limitations and disadvantages associated with steam-type heating pads, particularly in terms of the time taken to melt the liquid, researchers are exploring alternative methods for heating liquid within the Flexitank. This project aims to investigate the possibility of implementing electrical heating pads as an option for liquid heating in liquid transportation. Various types of electrical heating pads have been studied to explore their characteristics and operational capabilities. Experimental testing has been conducted on several electrical heating pads to compare their characteristics, especially in terms of the desired temperature requirement for specific liquid temperatures, as well as current consumption for each heating pad. This study will assist in determining the best option for implementing electrical heating pads in Flexitank. The results show a promising future for electrical heating pads in Flexitank, but further study is required to examine various heating pad arrangements in actual implementation.

Heating decoys to mimic thermal signatures of live animals for drones

Thermal sensors mounted on drones (unoccupied aircraft systems) are popular and effective tools for monitoring cryptic animal species, although few studies have quantified sampling error of animal counts from thermal images. Using decoys is one effective strategy to quantify bias and count accuracy; however, plastic decoys do not mimic thermal signatures of representative species. Our objective was to produce heat signatures in animal decoys to realistically match thermal images of live animals obtained from a drone-based sensor. We tested commercially available methods to heat plastic decoys of three different size classes, including chemical foot warmers, manually heated water, electric socks, pad, or blanket, and mini and small electric space heaters. We used criteria in two categories, 1) external temperature differences from ambient temperatures (ambient difference) and 2) color bins from a palette in thermal images obtained from a drone near the ground and in the air, to determine if heated decoys adequately matched respective live animals in four body regions. Three methods achieved similar thermal signatures to live animals for three to four body regions in external temperatures and predominantly matched the corresponding yellow color bins in thermal drone images from the ground and in the air. Pigeon decoys were best and most consistently heated with three-foot warmers. Goose and deer decoys were best heated by mini and small space heaters, respectively, in their body cavities, with a heated sock in the head of the goose decoy. The materials and equipment for our best heating methods were relatively inexpensive, commercially available items that provide sustained heat and could be adapted to various shapes and sizes for a wide range of avian and mammalian species. Our heating methods could be used in future studies to quantify bias and validate methodologies for drone surveys of animals with thermal sensors.•We determined optimal heating methods for plastic animal decoys with inexpensive and commercially available equipment to mimic thermal signatures of live animals.•Methods could be used to quantify bias and improve thermal surveys of animals with drones in future studies.

How does carbon trading price matter for bank loans? Evidence from Chinese banking sector

This paper investigates the impact of carbon trading prices on Chinese commercial banks. We propose a stress test model to calculate the decline of firms’ liabilities and the climate-driven loss of commercial banks to different industries. The results indicate that State-Owned Banks suffer the highest climate-driven loss among all types of banks. City commercial banks suffer the highest climate-driven loss ratio since they maintain a relatively low level of Tier 1 core capital. Beijing, Shanghai, Jiangsu, and Zhejiang maintain the highest levels of climate-driven loss ratio. Furthermore, the allocation of loans portfolio across different industries also influences climate-driven loss of banks. The climate-driven loss to the electric power, heat, gas, and water production and supply sector is the largest in all industries. It is necessary for banks to incorporate climate factors into the risk assessment framework.

Direct Electric Heating in Chemical Processes (A Review)

Direct Electric Heating in Chemical Processes (A Review)

Remediation of seawater polluted by oil spills via integrating porous materials with phase-change materials

The cleanup of viscous oil spills, especially in frigid regions, presents significant challenges due to the low fluidity of the oil. While the integration of absorption materials with photo/electric thermal conversion has shown significant promise, its effectiveness can be greatly influenced by environmental factors. To address these challenges, this study introduces an innovative solution: three-dimensional porous materials (3D-PMs) combined with phase change materials (PCMs). By utilizing energy pre-stored in PCMs through sunlight irradiation or electric heating, heat can be efficiently released when 3D-PMs come into contact with crude oil. A novel superhydrophobic melamine sponge (PPCPP@MS), composed of polypyrrole (PPy) and polyethylene glycol (PEG), has been developed for this purpose. The PPy polymerization layer reliably converts light/electricity into heat, while the PEG‑carbon nanotube (CNT) composite coating layer facilitates heat storage and release. This innovative design significantly enhances safety, energy utilization efficiency, and operational effectiveness. Furthermore, COMSOL simulation was employed to the interfacial heat transfer and phase transformation process of PPCPP@MS during crude oil absorption. Demonstrating stable heat release and oil-adsorbing performance in simulated low-temperature marine environments, PPCPP@MS exhibits great potential for addressing oil spills in extreme climates. The innovative design of PPCPP@MS offers crucial insights for managing viscous oil spills, particularly in frigid regions, providing a promising approach in environmental protection and remediation efforts.

Performance and Parametric Studies of a Non-Compact Hybrid PV-CSP Power Plant Integrated by a Supercritical Rankine Cycle and an Electric Heater in Series

This study focuses on performing a parametric analysis of the non-compact concentrated solar power (CSP)-photovoltaic (PV) hybrid plant combined with an electric heater (EH) and a Supercritical Rankine Cycle as well as a multi-objective optimization of different technologies. The power plant sizing is evaluated in a baseload dispatch scenario of 165 MWe for a location in Seville and considering combinations of the PV installed power, CSP solar multiple (SM), thermal energy storage (TES) capacity and EH power. Studied parametric combinations are optimized for minimizing the Levelized Cost of Electricity (LCOE) and maximizing the capacity factor (CF), with the ultimate goal of achieving the Pareto front. The results of the study show that certain combinations, such as PV=450 MWe, SM=2, EH=250 MW, and TES=12 h, have a favourable balance between the LCOE and the CF (LCOE=0.0979 €/kWh, CF=0.702). In addition, the results obtained through the optimization process, in particular by considering the Pareto frontier, indicate that among the different technologies, the CSP-PV-TES-EH configuration has the lowest LCOE and the highest FC.

Supercritical Water Gasification of Biomass on CSP Plants: Comparison of On-Sun and Off-Sun Designs

A comparative study of On-Sun and Off-Sun designs for supercritical water gasification (SCWG) of biomass on concentrated solar power (CSP) plants was here presented. In the On-Sun design, the tubular reactor was placed on a cavity receiver of a solar power tower (SPT) plant and the heat employed to produce the gasification came directly from the sun (viz. the solar radiation was concentrated, thanks to the heliostat field, onto the tube's surface). In the Off-Sun designs, the gasification of the biomass was carried out inside a heat exchanger and it was produced thanks to the heat absorbed from the hottest fluid, which can be obtained from CSP plants or electrical heating. This work numerically investigated the thermomechanical performance of both designs. The results stood out the relation between temperature-gas yield-thermal stress. In On-Sun configurations the gas yield was 5 times higher than those obtained in the Off-Sun configuration. However, the highest values of both temperature and stress may produce the failure of the reactor. This fact could be avoided in an Off-Sun reactor, since its uniform heating conditions mitigate the maximum temperature and stresses.

Comparison of Parabolic Troughs and Solar Photovoltaic as Solar Field Technology in Dispatchable Solar Power Plants

The use of thermal energy storage (TES) technologies, as means to provide dispatchability to thermally driven solar power production, has long stood as the main argument for the interest and potential competitiveness of Concentrated Solar Power (CSP) when compared to other non-dispatchable alternatives. Whereas reductions of the Levelized Cost of Electricity (LCOE) are observed for CSP in recent years, the notable LCOE reduction observed along this decade in large-scale solar photovoltaics (PV) plants is set to break the taboo of "power-to-heat-to-power" approaches, as its potential economic performance outcasts the associated thermodynamic inefficiency. The possibility of using available resistive heating technologies and components in PV-TES combinations, renders the configuration of a conventional CSP plant suitable for the replacement of a thermal conversion solar field by a photovoltaic field presenting further the possibility of delocalization and/or spatial distribution of the solar field (e.g. on a Carnot Battery configuration). As dispatchability no longer stands as an exclusive argument in favor of CSP over PV, the present article addresses the boundary conditions for the competitiveness of each technology as the champion of dispatchable solar power fields. The impact of both land and electrical heater costs variation in the variation of LCOE for PV-TES plants is much more modest than that observed for the impact of CSP solar field cost variations in the variation of LCOE for CSP plants, which leans for the latter and at present costs, towards better competitiveness for plant designs with a storage capacity in excess of 10.0 FLH (for GHI values in excess of 2100-2200 kWh∙m-2∙year-1).