Electrothermal Heating Research Articles

Enhancement of interface thermal conductance between Cr–Ni alloy and dielectric via Cu nano-interlayer

Facilitating interfacial thermal transport is highly desirable for various engineering applications, such as improving heat dissipation in microelectronics and efficiency of electrothermal heating element. Here, the interface thermal conductances (ITCs) of Cr0.22Ni0.78/MgO and Cr0.22Ni0.78/Al2O3 interfaces are studied through the non-equilibrium molecular dynamics simulation. It is found that the two ITCs can be hugely enhanced by 3 and 2.4 times, respectively, with the introduction of Cu nano-interlayer of a thickness larger than 7.2 Å. The enhanced ratio is robust and shows weak dependence on temperature. Further vibrational spectral analysis and phonon transmission function reveal that the enhancement in ITC mainly originates from the boosting of inelastic phonon scattering, which is generally considered to contribute a small proportion to ITC. Here, the inelastic scattering contributes as high as 63% to the ITC of Cr0.22Ni0.78/Cu/MgO interface at 300 K. The findings provide an effective strategy to enhance ITC at a wide temperature range and advance our understanding of inelastic scattering in interfacial phonon transport.

Hybrid System Combining Ice-Phobic Coating and Electrothermal Heating for Wing Ice Protection

In-flight icing for aircraft is a large concern for all those involved in aircraft operations. Generally, an electric heater has been used to prevent in-flight icing. A hybrid anti-icing system combining ice-phobic coating and electrothermal heating (ICE-WIPS) has been proposed by the Japan Aerospace Exploration Agency (JAXA) to reduce the power consumption in the heating unit. In order to validate the effectiveness of ICE-WIPS, validation and demonstration tests are conducted using icing wind tunnels at the Kanagawa Institute of Technology (KAIT) and at the Icing Research Tunnel in the NASA Glenn Research Center. Using a NACA0012 airfoil as a test model, ICE-WIPS demonstrates substantial reduction in power consumption as compared to the existing heating system. The reduction depends on the in-flight icing conditions; more than a 70% reduction is achieved at a liquid-water content (LWC) of 0.6 g/m3 and a median-volume diameter (MVD) of 15 μm at 75 m/s with zero angle of attack. In wet-icing conditions, more than a 30% reduction in power is achieved.

A flexible and stretchable polypyrrole/knitted cotton for electrothermal heater

Abstract Electrothermal heater (ETH) is very promising in wearable electronic area for its potential thermotherapy and electrical-warming garment applications. To fabricate a suitable conductive material for wearable ETH, knitted cotton is used as substrate for in-situ polymerization of pyrrole monomers, producing conductive polypyrrole/knitted cotton fabric (PKCF) with good flexibility and stretchability. A parallel strategy for current collectors is taken to enhance the temperatures of prepared PKCF from 37.0 to 51.0 °C at 8 V. This PKCF provides a service time about 13.5 h in a continuous electrothermal process, keeping a temperature above 35 °C. Besides, the PKCF still shows good electrothermal performances after bent or stretched several thousand times, and can be sewn on fabric to realize its electrothermal function in garments, which indicates a promising wearable market.

Flexible electrothermal polymer film based on reduced graphene oxide–water polyurethane

In this paper, waterborne polyurethane (WPU) conductive films incorporated with reduced graphene oxide (RGO) as conductive fillers were prepared by solution blending and tape casting method. The electrical conductivity, thermal conductivity and microstructures of the composite films were systematically investigated. The experimental results demonstrate that the electrical conductivity and thermal conductivity of the RGO–WPU composite films first increased then decreased with the increase of the RGO content. The resistivity of composite film with 7% RGO reaches to the smallest that is about [Formula: see text], and the thermal conductivity of the composite film with 7% graphene was about 0.29 W.m.K[Formula: see text], which an increase of 70% compared with pure WPU. The electrical conductivity of the composite film decreased with the increase of the original concentration of WPU solution and thickness of the composite film. As film heater, the composite film displayed effective and rapid heating at low input voltages owing to the good conductivity. With an input voltage was in the range of 10–24 V, the film took less than 30s to reach a steady-state temperature, demonstrating the fast response of the composite film heater and suitable for applications in the field of the fast temperature switching with low input voltages as flexible electrothermal heater.

Enhanced performance of direct contact membrane distillation via selected electrothermal heating of membrane surface

Membrane distillation (MD) is a thermally driven separation process with great potential, but is currently limited by low energy efficiency. Heating of the entire circulating feed represents a major source of energy consumption in MD. Here, we present electrically conductive carbon nanostructure (CNS-) coated polypropylene (PP) membranes as a possible candidate to mitigate energy consumption through selected electrothermal heating of the membrane surface. A membrane for MD was coated with CNS using a tape casting technique. The resulting CNS-PP membrane is hydrophobic, and its smaller pore size and narrow pore size distribution resulted in a higher liquid entry pressure compared to the uncoated PP membrane. An increase in surface temperature was observed when a current was passed through the conductive CNS layer. The CNS layer on the PP membrane acts as an electrothermal heater when an AC potential is applied, and the rate of heating is proportional to the amplitude of applied AC potential. We applied electrothermal heating of these membranes to desalination by direct contact membrane distillation, in conjunction with heating of the circulating feed, and compared the performance with and without application of AC bias at three feed temperatures viz. 40, 50 and 60 °C. Applying a potential across the CNS layer increased permeate flux by 75, 76 and 61% at feed temperatures of 40, 50 and 60 °C respectively, while maintaining a salt rejection of >99%. This increase in flux is accompanied by a reduction in specific energy consumption of greater than 50% for all three feed temperatures. By combining electrothermal surface heating with MD, this study paves the way for smart, low-energy MD systems.

Laser-Induced Graphene Paper Heaters with Multimodally Patternable Electrothermal Performance for Low-Energy Manufacturing of Composites.

Low-energy manufacturing of polymeric composites through two-dimensional electrothermal heaters is a promising strategy over the traditional autoclave and oven. Laser-induced graphene paper (LIGP) is a recent emergent multifunctional material with the merits of one-step computer aided design and manufacturing (CAD/CAM) as well as a flexible thin nature. To fully explore its capabilities of in situ heating, herein, we adventurously propose and investigate the customizable manufacture and modulation of LIGP enabled heaters with multimodally patternable performance. Developed by two modes (uniform and nonuniform) of laser processing, the LIGP heaters (LIGP-H) show distinctively unique characteristics, including high working range (>600 °C), fast stabilization (<8 s), high temperature efficiency (∼370 °C·cm2/W), and superb robustness. Most innovatively, the nonuniform processing could section LIGP-H into subzones with independently controlled heating performance, rendering various designable patterns. The above unique characteristics guarantee the LIGP-H to be highly reliable for in situ curing composites with flat, curved, and even inhomogeneous structures. With enormous energy-savings (∼85%), superb curing accuracy, and comparable mechanical strength, the proposed device is advantageous for assuring high-quality and highly efficient manufacturing.

Carbon fiber/poly ether ether ketone composites modified with graphene for electro-thermal deicing applications

Carbon fiber/poly ether ether ketone (Cf/PEEK) composites are a class of high performance, continuous fiber reinforced thermoplastic polymer materials. These composites have the potential to meet demands for self-cleaning or deicing applications in the power supply industry in cold regions. In this study, the effect of graphene on the deicing performance of Cf/PEEK composites through electro-thermal Joule heating was investigated. First, graphene/PEEK composites with varying graphene content of up to 6 wt% were fabricated and characterized. Adding up to 5 wt% graphene was found to improve the electrical conductivity, thermal conductivity, and the crystallinity of PEEK. However, at a graphene content of 6 wt%, the crystallinity and thermal conductivity of the mixture decreased, likely due to agglomeration of graphene. Next, graphene modified Cf/PEEK composites (0 and 5 wt% graphene) with resin volume fractions of 40, 50, and 60 vol% were prepared by hot pressing. Graphene was found to increase the electrical conductivity of the composites by roughly 100%, and to improve the efficiency of converting Joule heating to useful deicing energy by up to 35%.

Efficient exfoliation of UV-curable, high-quality graphene from graphite in common low-boiling-point organic solvents with a designer hyperbranched polyethylene copolymer and their applications in electrothermal heaters

The use of stabilizer with designer structures can effectively promote graphite exfoliation in common solvents to render functionalized graphene desirable for their various applications. Herein, a hyperbranched polyethylene copolymer, HBPE@Py@Acryl, simultaneously bearing multiple pyrene terminal groups and pendant acryloyl moieties has been successfully synthesized from ethylene with a Pd-diimine catalyst based on unique chain walking mechanism. The unique structural design of the HBPE@Py@Acryl makes it capable of effectively promote graphite exfoliation in a series of common, low-boiling-point organic solvents, e.g. CHCl3, to render stable graphene dispersions with concentrations effectively adjustable by changing feed concentrations of graphite and polymer or sonication time. Meanwhile, it can be irreversibly adsorbed on the exfoliated graphene surface based on the π-π interactions between them to concurrently render acryloyl-functionalized graphene free of structural defects, with majority (92.7%) of them having a thickness of 2–3 layers. This allows us to obtain graphene electrothermal films simply by filtration and UV irradiation, which exhibit outstanding stability in use. The action mechanism of the HBPE@Py@Acryl as stabilizer for promoting graphite exfoliation and the role of UV irradiation on improving the stability in use of resulting graphene films have been elucidated.

A low voltage, flexible, graphene-based electrothermal heater for wearable electronics and localized heating applications

Recent years have seen a rapid increase in the level of sophistication in modern day devices which has given rise to the demand for better performance in all of their components, one of which is the heating element. Two excellent approaches to this need would be to improve the materials from which these Joule’s heating elements are made and the other to design improved heater geometries for best temperature distribution. In this paper, we discuss a high performance electrothermal heater prepared from laser reduced graphene oxide (LrGO) deposited on Polyethylene Terephthalate (PET) flexible Substrate. The surface morphology and structural properties of the prepared LrGO films were investigated by means of Scanning Electron Microcopy (SEM), X-Ray Diffraction (XRD) and Raman Spectroscopy (RS). Electrothermal (ET) responses of the fabricated electrothermal heaters to different driving DC voltages were studied by Infrared thermal Imagery. An electrothermal heater with a low Sheet resistance of ∼52 O/square was fabricated and it can attained a steady state temperature of up to 135 °C in only 10 s when a low voltage of 9 V was applied. A finite Element model (FEM) was prepared for this heater which agreed well with the experimental results. Power consumption for this heater is as low as 0.389 W/cm2, making it a suitable candidate for energy-saving applications such as wearable electronic.

Preparation of polypyrrole coated on Polyester Cleanroom Wiper as heater device

Recently, many efforts have been dedicated to achieve lightweight, stretchable, and flexible heat device. Here, the Polyester Cleanroom Wiper coated with poly(pyrrole) as flexible material showing electrothermal properties are reported. Poly(pyrrole) particles are synthesized on the cloth via a simple in situ polymerization method with different Py/FeCl3 concentration ratios. A highly conductive cloth with surface resistance of 23 Ω/sq can be produced by changing the Py/FeCl3 concentration. The flexible composites showed sensitive electrothermal performance, and a steady-state temperature of 89.1°C could be reached at 6 V. In addition, temperature, voltage, and time-dependent temperature results showed that the heating performance was strongly dependent on the resistance and external voltage. Herein, as-prepared composites were further analyzed as ultra-fast responding electrothermal heaters, indicating their great potential in application value as wearable electronic textiles.

Heavy metal contamination in tilapia, Oreochromis niloticuscollected from different fish markets of Mymensingh District

The study was conducted to determine heavy metals viz; lead (Pb), Zinc (Zn), Arsenic (As), Chromium (Cr), and Cadmium (Cd) concentration in tilapia (Oreochromis niloticus) collected from different fish markets (Borobazar fish market, Shesmore fish market, Kamal-Ranjit market, Sutiakhali fish market, Machuabazar fish market and Shamvuganj fish market) of Mymensingh district from July 08, 2018 to January 15, 2019. After collection, electro-thermal heater digestion of the samples was carried out in Nutrition Laboratory, Department of Aquaculture, Bangladesh Agricultural University (BAU) and finally heavy metal concentrations were determined by Atomic Absorption Spectrometer (AAS) in the Interdisciplinary Institute for Food Security (IIFS) Laboratory, BAU. The average Pb, Zn, Cr, and Cd concentrations (mg/kg) in the examined samples were 1.67 mg/kg, 118.68 mg/kg, 0.97 mg/kg, and 0.59 mg/kg, respectively. The average Arsenic concentrations in all tilapia samples were found to be below detectable limit (BDL). The study revealed that the average Zn and Cr concentration of tilapia flesh samples in Mymensingh were considerably higher than maximum recommended limit of World Health Organization (1989) and Food and Agricultural Organization (1983) and hence human health safety issues for the local consumer should be taken into consideration by the concerned authorities.

Highly effective E-heating performance of nickel coated carbon fiber and its composites for de-icing application

We propose a wing-shaped composite structure that uses an electroless nickel-plated carbon fabric as an electro-thermal heating element, thus improving the electrical and thermal properties. The results showed that the electro-thermal conversion efficiency increased from 0.064 to 0.054 W/°C with increasing plating thickness and weight percentage of the nickel particles deposited. The experiments demonstrated that the surface temperature of the wing-shaped composite could be heated up to 87.9 °C within 1000 s at an applied power density of 2.11 kW/m2. The measurement results agreed well with those of the coupled electro-thermal simulations of heating elements related to a resistance heating phenomenon via an electro-thermal conversion, and it validated the heating performance. In addition, the nickel-plated carbon fabric as a heating element for the leading edge of the wing-shaped model was examined using a multiphysics de-icing simulation under actual icing conditions from a practical perspective. Most of the icing was removed by applying a power density of 2.7 kW/m2 for 600 s to the wing-shaped composite structure. An interlaminar shear strength (ILSS) test was performed to verify the mechanical performance in terms of structural integrity. This practical approach could efficiently offer a desirable solution for the multifunctional de-icing composite field.

Assembly of carbon nanodots in graphene-based composite for flexible electro-thermal heater with ultrahigh efficiency

A high-efficiency electro-thermal heater requires simultaneously high electrical and thermal conductivities to generate and dissipate Joule heat efficiently. A low input voltage is essential to ensure the heater’s safe applications. However, the low voltage generally leads to low saturated temperature and heating rate and hence a low thermal efficiency. How to reduce the input voltage while maintaining a high electro-thermal efficiency is still a challenge. Herein, a highly electrical and thermal conductive film was constructed using a graphene-based composite which has an internal three-dimensional (3D) conductive network. In the 3D framework, cellulose nanocrystalline (CNC) phase with chiral liquid crystal manner presents in the form of aligned helix between the graphene oxide (GO) layers. Carbon nanodots (CDs) are assembled inside the composite as conductive nanofillers. Subsequent annealing and compression results in the formation of the assembled GO-CNC-CDs film. The carbonized CNC nanorods (CNR) with the helical alignment act as in-plane and through-plane connections of neighboring reduced GO (rGO) nanosheets, forming a conductive network in the composite film. The CDs with ultrafast electrons transfer rates provide additional electrons and phonons transport paths for the composite. As a result, the obtained graphene-based composite film (rGO-CNR-CDs) exhibited a high thermal conductivity of 1,978.6 W·m−1·K−1 and electrical conductivity of 2,053.4 S·cm−1, respectively. The composite film showed an outstanding electro-thermal heating efficiency with the saturated temperature of 315 °C and maximum heating rate of 44.9 °C·s−1 at a very low input voltage of 10 V. The freestanding graphene composite film with the delicate nanostructure design has a great potential to be integrated into electro-thermal devices.

Energy saving strategy for the development of icephobic coatings and surfaces

Aircraft are frequently exposed to cold environments and ice accumulation on aircraft surface may lead to catastrophic accidents. An effective solution of ice protection is a critical requirement in the aerospace industry. For the research and development of icephobic coatings, the current coating design target mainly focuses on lowering the ice adhesion strength between the ice and the surface. However, as a passive ice protection approach, the use of icephobic coating often has to be combined with an active ice protection solution (e.g. electro-thermal heating, hot air bleeding, and vibration, etc.), especially for the in-flight application where the reliability of ice protection must be ensured. Therefore, ice adhesion strength is no longer the sole criterion to evaluate the icephobic performance of a coating or a surface. It is a need to establish a more practical strategy for the design of icephobic coatings and surface. In this work, an energy saving strategy is proposed to assess the de-icing performance of the icephobic coating and surface when active heating is involved. The energy consumed for the de-icing operation assisted by the ice gravity is used as the key criterion for the overall performance of icephobic coating and surface. Successful validation has been achieved for evaluating the de-icing performance of selected coatings and surfaces, which demonstrates an alternative strategy for the design and practical application of icephobic coatings and surfaces in ice protection.

Prospects for the use of electro-technological heating systems in the arctic conditions

Introduction.The co-authors analyze the sources and consumers of thermal power in the Far North and the Arctic region. The co-authors describe industrial, fire, and environmental hazards coming from existing heating systems that consume burned hydrocarbons. The co-authors propose an alternative system that uses electro-thermal technologies.Subject of research.Electro-thermal systems designated for the maintenance of the operation of industrial and social facilities in the Far North and the Arctic region.Objective.Substantiation of the need to have flame heating systems, which are currently in operation, replaced by highly efficient, safe and eco-friendly electro-thermal heating systems in the Far North and the Arctic region.Materials and methods.The co-authors analyze thermal power generation in the environment characterized by extremely low temperatures.Findings.The co-authors describe several heating sources that comprise electro-thermal technologies, applicable in the Far North and the Arctic region.Conclusions.Electro-thermal heating systems boost heat transmission and power efficiency of heating systems due to their high controllability. They can also reduce the environmental impact, caused by strong heat flows produced by flame furnaces onto the climate of the Far North and the Arctic region.

Electrothermal Flexibility for Demand Response Using Inverse Simulation

This paper provides a hierarchical optimization algorithm based on the inverse simulation for the exploitation of the flexibility of electrothermal heating systems in office buildings in a demand response schema led by an aggregator. Inverse simulation, based on the approximate differentiation method, is applied on local building level to turn the customer's comfort specifications, i.e., indoor temperature comfort zone, into the technical power and flexibility specifications and, hence, acceptable power schedules. The aggregator then optimizes for a global system level objective. We prove that the inverse simulation yields the same result as the forward simulation approach, whereas it protects the privacy and thermal comfort of the customer. Moreover, via a general use case, we provide an insight on how to optimally balance demand and supply on the system level.

Dual-Ligand Fe-Metal Organic Framework Based Robust High Capacity Li Ion Battery Anode and Its Use in a Flexible Battery Format for Electro-Thermal Heating

Metal organic frameworks (MOFs) have been attracting recent scientific attention as battery electrode materials due to the ease of tailoring their structure, porosity, and properties by varying the...

Transparent Electrothermal Heaters Based on Vertically-Oriented Graphene Glass Hybrid Materials.

Transparent heating devices are widely used in daily life-related applications that can be achieved by various heating materials with suitable resistances. Herein, high-performance vertically-oriented graphene (VG) films are directly grown on soda-lime glass by a radio-frequency (rf) plasma-enhanced chemical vapor deposition (PECVD) method, giving reasonable resistances for electrothermal heating. The optical and electrical properties of VG films are found to be tunable by optimizing the growth parameters such as growth time, carrier gas flow, etc. The electrothermal performances of the derived materials with different resistances are thus studied systematically. Specifically, the VG film on glass with a transmittance of ~73% at 550 nm and a sheet resistance of ~3.9 KΩ/□ is fabricated into a heating device, presenting a saturated temperature up to 55 °C by applying 80 V for 3 min. The VG film on the glass at a transmittance of ~43% and a sheet resistance of 0.76 KΩ/□ exhibits a highly steady temperature increase up to ~108 °C with a maximum heating rate of ~2.6 °C/s under a voltage of 60 V. Briefly, the tunable sheet resistance, good adhesion of VG to the growth substrate, relative high heating efficiency, and large heating temperature range make VG films on glass decent candidates for electrothermal related applications in defrosting and defogging devices.

Innovative electrotechnological systems to provide the temperature modes of technological pipelines

Introduction: the systems of thermal effects on thermo-dependent, viscous and highly viscous liquids under conditions of the Arctic and the Extreme North are considered. Low efficiency and danger of heating systems based on burned hydrocarbons, heated liquids and steam are shown. Electrothermal heating systems used to maintain thermo-dependent fluids in a fluid state are considered. The evaluation of the effectiveness of the application of the most common electrothermal system — heating cables (tapes). The most effective electrothermal system based on induction technologies has been determined. Materials and methods: considered methods of thermal exposure to maintain the fluid properties of thermo-dependent fluids at low extreme temperatures. Results: presents an induction heating system and options for its implementation in the Extreme North and the Arctic. Conclusions: induction heating system to minimize loss of product quality, improve the system performance under changing process conditions, eliminate fire product, to reduce the influence of the human factor.

Flexible conductive copper/reduced graphene oxide coated PBO fibers modified with poly(dopamine)

Nowadays, flexible fiber heater has attracted great interests. Here, we fabricated a copper/reduced graphene oxide (Cu/RGO) hybrids coating on the surface of poly(p-phenylene benzobisoxazole) (PBO) fiber with excellent tensile strength, high thermal stability and high flame retardancy for electrothermal heater. Copper was plated on the surface of PBO fibers by the modification of the PBO fibers with poly(dopamine) followed by RGO activation and electroless copper plating and copper coated PBO fibers (Cu/RGO-PBO) is obtained. Poly(dopamine) and RGO acted as synergistic activating agents for electroless copper plating. Cu/RGO-PBO fibers exhibit low electrical resistance of 0.16 Ω cm−1 and possess excellent electrical conductivity even after 20 cycles of washing. The heating temperature of Cu/RGO-PBO fibers is steady at around 44 °C which is suitable for keeping body warm. Additionally, Cu/RGO-PBO fibers reveal a low corrosion current density of 2.46 μA cm−2. The result indicates flexible Cu/RGO-PBO fibers with excellent electrical conductivity, heating performance and corrosion resistance, which could be used as flexible electrically conductive fiber and wearable heater with corrosion resistance.