Energy-saving Devices Research Articles

Four-State Electrochromism in Tris(4-aminophenyl)amine- terephthalaldehyde-based Covalent Organic Framework.

Covalent organic frameworks (COFs) are of massive interest due to their potential application spanning diverse fields such as gas storage and separation, catalysis, drug delivery systems, sensing, and organic electronics. In view of their application-oriented quest, the field of electrochromism marked a significant stride with the reporting of the first electrochromic COF in 2019 [J. Am. Chem. Soc. 2019, 141, 19831-19838]. Since then, new and novel COF structures with electrochromic features (denoted as ecCOFs) have been searched continuously. Yet, only a handful of ecCOFs have been constructed to date. A closer look at these reports suggests that multielectrochromism (showing at least three redox color states) in a COF assembly has only been achieved once, manifested through three-state electrochromism [Angew. Chem. 2021, 133, 12606-1261]. Herein, we report four-state electrochromism in tris(4-aminophenyl)amine-terephthalaldehyde (TAPA-PDA)-based COF constructed through the metal-catalyst free Schiff base approach. The four-state (orange, pear, green, and cyan) electrochromism demonstrated by the TAPA-PDA ecCOF opens several futuristic avenues for ecCOF's end use in flip-flop logic gates, intelligent windows, decorative displays, and energy-saving devices.

Influence of energy-saving devices on the hydrodynamic characteristics of a waterjet-propelled ship: Experimental and numerical investigation

Installing stern energy-saving devices can help conserve energy and enhance ship speed, particularly for medium-to-high-speed ships. This study focuses on a waterjet-propelled ship and examines the performance of two energy-saving devices: the interceptor and stern flap. The investigation involves conducting a comparative analysis through towing-tank experiments and utilising Reynolds-averaged Navier–Stokes (RANS) numerical methods. The findings suggest that incorporating energy-saving devices alters the capture flow of the waterjet-propelled ship. Furthermore, these devices reduce ship resistance, resulting in a maximum decrease in the impeller speed of the self-propulsion point up to 5%. Following the installation of energy-saving devices, the propulsion efficiency of the waterjet-propelled ship demonstrates an enhancement ranging from 0.5% to 5.7%. This increase in propulsion efficiency emerges as a principal factor contributing to the energy savings facilitated by the stern energy-saving device. Upon comparison, it was found that within the Fr range of 0.3–0.5, the stern flap exhibited a superior energy-saving effect. Conversely, when Fr exceeded 0.5, the interceptor demonstrated a more pronounced energy-saving effect. Finally, the mechanisms of the stern energy-saving devices are elucidated based on the momentum velocity coefficient, thrust deduction fraction, and changes in the internal and external flow fields of the waterjet-propelled ship.

Fluid-Solid coupling analysis of PTFE impeller in hydraulic turbines for sewage resource utilization

Abstract Hydraulic turbines, vital energy-saving devices, convert pressure energy from liquid fluids into mechanical energy. As wastewater resource utilization and zero discharge industries proliferate, relevant research is of great interest. In order to design a suitable medium and low pressure hydraulic turbine for industrial water treatment, we conducted a study analyzing the stress and strain characteristics of a PTFE turbine impeller by means of bi-directional fluid-structure coupling numerical simulation. Our findings suggest that the impeller’s maximum equivalent stress and maximum deformation fall within acceptable material limits, with stress concentration at the blade-cover plate interface. The blade experiences maximum deformation at its midpoint due to high liquid pressure on the volute periphery. Fluid solid coupling reduces the maximum equivalent stress of the impeller by about 1.65MPa and the maximum deformation of the blade by about 0.05mm. The equivalent stress at the sampling point fluctuates periodically, with a significant change in stress amplitude at the sampling point of the cover plate on one side of the support surface, increasing susceptibility to fatigue damage.

Tailoring microstructure in a soft-magnetic Fe-based amorphous-nanocrystalline alloy for high resistivity according to electrical percolation threshold

Superior soft-magnetic materials are necessary for the development of modern magnetic devices with energy-saving and high-power density requirements. However, improving the magnetism by nanocrystallization always brings about the sacrifice of resistivity, presenting a common trade-off in Fe-based amorphous-nanocrystalline alloys. Here, the comprehensive merits of both superior soft-magnetic properties (high saturation magnetization of 1.81 T and low coercivity of 3.8 A/m) and high resistivity of 117.2 μΩ·cm were obtained by precisely tailoring amorphous-nanocrystalline microstructure close to electrical percolation threshold for a Fe82.5B12P2C1Cu0.5Co2 amorphous alloy. The soft-magnetic properties are attributed to the low magnetic anisotropy stemming from high nuclei number density and ultrafine nanocrystalline grains of 9.2 nm. The high resistivity is associated with the electrical percolation behavior with a nanocrystalline volume threshold of 14.8 % in the composite alloy. The results provide an effective strategy to overcome the trade-off in traditional amorphous-nanocrystalline alloys, significant for applications in high-frequency, high-power, and energy-saving devices.

Highly stable Ag@Au nanowires micromesh as transparent conductive network for stretchable electrochromic modulator

The stretchable electrochromic modulator is one of the most promising energy-saving optoelectronic devices that can be integrated into smart portable and wearable electronics. A lot of focus has been on developing transparent conductive electrodes of stretchable electrochromic modulators, but they generally suffer from poor chemical stability, low photoelectric balance, and unsatisfactory deformability. To address this challenge, we first develop Ag@Au nanowires (NWs) micromesh-based stretchable transparent conductive electrodes (STCEs) using a self-assembled approach, which displays superior photoelectric performance (8.5 Ω sq-1 with a transmittance of 81.5 %), good chemical stability in harsh electrolyte environment (acidic and alkaline) as well as robust mechanical stability (bending, folding, stretching and twisting). As a demonstration, the grown WO3 on Ag@Au NWs-based STCEs can deliver good electrochromic stability even after bending over 1000 cycles and stretching to 50 %. Moreover, highly soft Zn//WO3 and polyaniline (PANI)//WO3 electrochromic modulators were assembled using flexible Ag@Au micromesh STCEs, which still retain uniform electrochromism in neutral and acidic electrolytes respectively. Definitionally, the strategy of in-situ grown Au shell on the surface of AgNWs micromesh provides an innovative solution to fabricate high-performance STCEs for the related portable smart wearable electronic devices.

High-contrast electrochromic coatings and devices for health assurance, visual comfort and energy-saving in buildings

High-contrast electrochromic coatings and devices reduce the ultraviolet-radiation from sunlight, ensure human health and visual comfort, save the electricity consumption of the heater in winter, and save electricity consumption of air conditioners in summer. Anodically coloring polymer coatings (P(CDBP), P(CDBP-co-BTPH), P(CDBP-co-TFU), P(CDBP-co-CDT) and P(CDBP-co-CDTK)) based on 4,4′-bis(carbazol-9-yl)-2,2′-dimethylbiphenyl (CDBP) and four different dithiophene derivatives (2,2′-bithiophene (BTPH), 2-(2-thienyl)furan (TFU), 4H-cyclopenta[2,1-b:3,4-b’]dithiophene (CDT), and cyclopentadithiophene ketone (CDTK)) are polymerized electrochemically on ITO electrode. The P(CDBP-co-BTPH) electrochromic coating has high transmittance change (ΔT = 71.1 %) and coloration efficiency (160.6 cm2 C−1). P(CDBP-co-BTPH) film reveals yellow-gray and dark blue in neutral and oxidation states, respectively. Electrochromic energy saving devices (ECDs) are assembled using P(CDBP), P(CDBP-co-BTPH), P(CDBP-co-TFU), P(CDBP-co-CDT) and P(CDBP-co-CDTK) films as the anodic layers and poly(3,4-(2,2-dimethylpropylenedioxy)thiophene) (PPD-M2) film as the cathodic layer. P(CDBP-co-BTPH)/PPD-M2 ECD shows a high transmittance change (ΔT = 30.3 %) and a rapid response time (≤0.3 s). Moreover, P(CDBP-co-BTPH)/PPD-M2 ECD also has sufficient optical memory and redox cycling stability. These findings provide us new insights for the useful design of polymer coatings in rapid switching electrochromic energy-saving devices and switchable architectural windows.

Interdiffusion mechanism of hybrid interfacial layers for enhanced electrical resistivity and ultralow loss in Fe-based nanocrystalline soft magnetic composites

Soft magnetic composites (SMCs) composed of ferromagnetic particles and insulating binder are highly desired in energy-saving and high-efficiency devices for their high electrical resistivity and softer saturation characteristics. However, traditional insulation coatings are facing thermal instability, inhomogeneous distribution, and magnetic dilution, presenting a major challenge for the trade-off relationship between power loss and permeability. Here, the phosphate-coated FeSiBCuNb/SiO2 SMC is successfully fabricated by a unique interdiffusion effect in hybrid interfacial layers, which shows a combination of ultralow power loss of 135.8 kW/m3 (50 kHz/100 mT), high effective permeability of 80.6, and good temperature stability. The interdiffusion behavior between Si/O and Fe/P/O elements promotes the formation of ultrathin, uniform, and multilayer interface structure, which alleviates the magnetic dilution. Penetrating oxidation at the edge interface and elements interdiffusion effect contribute to a higher electrical resistivity induced by hot isostatic pressing with rapid quenching, leading to a low eddy current loss. Synergistic effect of isostatic pressures and rapid quenching facilitates the formation of high-density Cu clusters corresponding to ultrafine microstructure, which is beneficial for low coercivity and low hysteresis loss. This study involves the interdiffusion mechanism of hybrid interfacial layers and nanocrystalline behavior, providing a new strategy for the next-generation of high-performance SMCs.

Research on the energy efficiency and sustainability

Mechatronics systems, by integrating mechanical, electronic, and computer technologies, offer a comprehensive solution to optimize the generation, transmission, storage, and utilization of energy, thus reducing energy waste. This paper begins by introducing the applications of mechatronics systems in renewable energy systems, encompassing the efficient capture and management of resources such as solar and wind energy to meet energy demands. Secondly, this paper discusses the critical role of mechatronics systems in smart grids, enhancing the efficiency and reliability of power systems through advanced monitoring and control technologies. Furthermore, this study emphasizes the value of mechatronics systems in designing and implementing energy-saving devices, including high-efficiency motors, intelligent lighting, and heat recovery technologies, to reduce resource wastage and environmental impact. Finally, by reducing carbon emissions and decreasing reliance on traditional energy sources, mechatronics systems actively contribute to sustainability, promoting the development of sustainable cities and buildings, and simultaneously achieving the United Nations Sustainable Development Goals.

Energy efficiency retrofitting measures of an institutional building: A case study in eastern India

Increasing energy demand and greenhouse gas emissions are major concerns in India. Building energy use in India accounts for 33 % of total energy consumption and is growing at an annual rate of 8 %. In order to save energy, energy conservation in buildings should be given primary importance. Energy conservation practices can reduce energy use in buildings while maintaining thermal comfort. This can be achieved by optimising existing energy use or lowering consumption. One such initiative was undertaken by Siksha 'O' Anusandhan Deemed to be University. It analysed the energy consumption pattern and possible energy conservation opportunities (ECOs) to lower energy usage in its buildings at campus 1 in Bhubaneswar. The Energy Conservation Building Code Odisha (OECBC) was followed to reduce energy use by replacing all the damaged windows with efficient glazing. By following OECBC guidelines, we can save up to 30 % of the energy consumed by an existing building. Besides, energy conservation measures were performed by replacing ceiling fans with brushless direct current (BLDC) fans, existing lights with LED bulbs, and using variable speed drives instead of induction motors. This study will help to define the most efficient energy conservation measures for existing buildings in terms of cost and energy savings. Retrofitting the present building with energy-saving devices will cost INR 21, 32, 90,152 with an overall annual energy savings of 47, 28,177 kWh and a yearly cost saving of INR 319,66,703.

Estimation of full-scale performance of energy-saving devices using Boundary Layer Similarity model

AbstractThe recent global trend toward decarbonization is also occurring in the maritime industry and there is an urgent need to improve the fuel efficiency of ships. Various energy-saving devices (ESDs) are adopted for this purpose. However, because of the difference in the boundary layer thickness between full-scale and model-scale, it is difficult to estimate the actual performance of ESDs in a tank test. As a solution to overcome this difficulty, the Boundary Layer Similarity model (BLS model) is proposed in which only the stern part of the hull is extracted to shorten the model length and to make its boundary layer thickness equivalent to that of a full-scale ship. By using this BLS model, the performance of ESDs on a full-scale can be estimated in a model test. In the present paper, the applicability of the BLS model is investigated by CFD (Computational Fluid Dynamics) simulations of performance estimation of an energy-saving fin in different locations for a bulk carrier. It is found that the BLS model is capable of predicting the full-scale performance of the fins by the model-scale simulations. Moreover, the flow fields affected by the fins with the BLS model are similar to those of full-scale. It is expected that the use of the BLS model enables the prediction of the full-scale performance of ESDs in a model test.

Electrolyte design for reversible metal electrodeposition-based electrochromic energy-saving devices

Reversible metal electrodeposition (RME)-based electrochromic devices have been attracting significant research interest due to their merits of low cost, simple configuration, and high extinction coefficients. As the key component in the electrochromic system, RME electrolytes with various metal ions and additives have endowed the RME device with flexible functionalities in energy-saving applications such as energy-efficient displays, smart windows, and camouflages. However, it is still challenging to research a widespread commercial application before some critical issues can be solved such as poor reversibility, low optical memory of the mirror state, and slow switching speed. Here, we offer a critical review of the recent progress of RME electrochromic devices based on aqueous, organic, ionic liquid, and eutectic electrolytes. Furthermore, the main challenges and perspectives for RME electrolytes are highlighted and discussed.

Exploring the Role of Airtightness for Achieving Carbon Neutrality in Canadian Residential Buildings: A Streamlined Life Cycle Assessment

This study delves into the relationship between airtightness levels and the entire life cycle carbon emissions of buildings across diverse Canadian climates. With the 2020 update of the National Energy Code of Canada for Buildings, whole-building airtightness testing was introduced as an option, prompting discussions on its mandatory nature. Using a net zero target, our assessment unfolds in two phases. Initially, we employ three-dimension (3D) modeling in Revit to replicate a typical Canadian detached house’s architectural features and material compositions. Subsequently, the model was imported into One Click life cycle assessment (LCA) to set parameters such as lifetime, gross interior area, and annual electricity consumption. Our analysis is bifurcated into assessing climatic conditions in Edmonton, Toronto, and Vancouver, alongside examining code-specified airtightness levels. We compared annual energy loss per unit area at varying airtightness levels accounting for the general deterioration of airtightness in new buildings during the pre-service phase to pinpoint the optimal airtightness value (ACH50) during the design stage. The subsequent phase evaluated increased carbon emissions from material replacement to meet this optimal airtightness condition and passive energy savings. Findings underscore that designing airtightness to an ACH50 value of 1.0 is the most energy-efficient. Comparative analysis reveals that achieving carbon neutrality solely through increased envelope airtightness and passive energy savings, is viable in Edmonton (18.4 years) owing to regional energy source disparities. In contrast, Toronto and Vancouver necessitate active energy-saving devices to attain carbon neutrality over the design lifetime.

Technological process and laws of change of energy consumption parameters of spinning enterprises

Textile industrial enterprises are composed of three main sectors, which differ significantly from each other in terms of energy capacity, and include - spinning, weaving and finishing departments. In comparison to other departments, spinning technological processes consumes the most electricity. It is necessary to use modern energy-saving devices and to improve technological processes in accordance with the requirements of the times. Building an energy balance based on the analysis of the enterprise's technological processes, as well as forecasting electricity consumption, is one of the urgent issues. In this article, the issues of energy saving and efficiency improvement and forecasting in spinning departments are considered.

Copper sulfide and polyelectrolyte decorated textiles for active/passive personal thermal management

The development of multifunctional textile-based personal thermal management devices is a prospective option for accurately warming the human body while effectively reducing energy consumption. However, existing multifunctional thermal management devices still face challenges in terms of high-performance integration. Here, we proposed an electrostatic-coordination-based strategy to fabricate successfully a versatile textile for body warming via sequentially covering cotton fiber with bio-based polyelectrolyte and in-situ grown copper sulfide coatings. The textiles with excellent solar/Joule heating properties and reduced infrared emissivity can efficiently heat the body in various environments and suppress thermal radiation dissipation from the body to the environment. Also, the textile realizes high-performance integration of electromagnetic shielding, UV protection, antimicrobial, and flame-retardant properties. This universal and efficient strategy provides a promising solution for the manufacture of all-day and energy-saving versatile personal thermal management devices, showing great potential for practical applications.

Author’s innovative technical solutions in the field of ecology and life safety for use in fuel-burning and ash-collecting devices

The study reviews and recommends fundamentally new technical solutions in the field of ecology and safety in the technosphere, confirmed by patents for inventions and utility models developed by scientists and graduate students of the Department of Technosphere Safety of the Far Eastern State Transport University. Innovative developments that are of practical interest and deserve attention include installations for preparing water-oil emulsions for combustion, energy-saving devices for environmentally friendly combustion of liquid fuels, rational designs of low-toxic gas and oil burners, as well as effective filter-cyclone and group cyclone devices for purification of flue gases from coal and fuel oil boiler and furnace units.

Ceramic Materials Based on Clay and Soapstone Waste: Thermo-Mechanical Properties and Application

In order to assess the feasibility of utilizing soapstone waste, which is generated during the production of stone blocks for fireplaces and other energy-saving devices, the effect of its addition to clay on the technological and thermal properties of ceramic materials was investigated. Two local clays and soapstone processing waste were characterized using XRD, SEM-EDS, XRF, DTA-TG, and granulometric analysis. The linear firing shrinkage, water absorption, density, flexural strength, thermal conductivity, specific heat capacity, and thermal shock resistance of the fired ceramic samples were analyzed. The results have shown that addition of soapstone waste to clay in an amount of 40 wt.% increases flexural strength, enhances thermal stability, and, additionally, reduces the thermal conductivity of the experimental samples. The technological properties of the final product meet the standard requirements for ceramic tiles.

Enhancing Gas Sensing Performance of TiO2-ZnO nanostructures: Effect of ZnO Concentration

Gas sensors based on titanium dioxide (TiO2) and zinc oxide (ZnO) nanocomposites are considered energy-saving devices that are utilized to find dangerous or harmful gases in an environment. The performance of nitrogen dioxide (NO2) gas sensors have been improved by spin-coating a TiO2 and TiO2:ZnO nanocomposite with varying concentrations (90TiO2:10ZnO, 70TiO2:30ZnO, and 50TiO2:50ZnO). To correlate structural properties with gas-sensing behavior, structural and morphological characterization has been done using FESEM, XRD, and EDX. Without any ZnO-specific crystalline phase, TiO2 X-ray diffraction was found to be indexed in the anatase crystalline structure. The ZnO is synthesized in the wurtzite phase with (002) orientation and has a smooth surface, according to the morphologies and crystalline structure of the films, which also indicated the presence of ZnO components with various crystallite sizes and lattice strains. Responses to NO2 are increased by low ZnO content. Additionally, at the average operating temperature of 250 oC, TiO2:ZnO shows a good response.

Maneuverability Performance of a KRISO Container Ship (KCS) with a Bulb-Type Wavy Twisted Rudder and Asymmetric Pre-Swirl Stator

The maneuverability performance of a KCS with energy-saving devices was investigated. A bulb-type wavy rudder and an asymmetric pre-swirl stator were used as energy-saving devices because their use resulted in considerable efficiency gain. A validated simulation method based on the maneuvering modeling group model was used for the simulation in this study. Turning circle, 10/10 zigzag, and 20/20 zigzag tests were simulated to compare various cases with and without a stator as well as conventional full-spade and bulb-type wavy rudders. Remarkable maneuverability performance was achieved, particularly with a bulb-type wavy rudder, and starboard–port unbalancing due to the one-directional propeller action was almost eliminated using these devices. The findings of this study will be useful in the development of more reliable autonomous maritime surface ships.

Ultrafast switching dynamics of the ferroelectric order in stacking-engineered ferroelectrics

Recent research has highlighted the potential of ferroelectricity in van der Waals bilayers in providing an unconventional route for improving device performance. Understanding the static and dynamic properties of domain wall (DW) is critical unlocking this potential, as key parameters such as switching field and speed heavily rely on them. In this article, we conduct a theoretical exploration of the fundamental properties of textures in stacking-engineered ferroelectrics using a machine-learning potential model. Our results demonstrate that competition between the switching barrier of stable ferroelectric states and in-plane lattice distortion leads to a DW width of ten nanometers. We also demonstrate that DW motion can drastically reduce the critical ferroelectric switching field of a monodomain by two orders of magnitude and enable domain switching on a picosecond timescale, suggesting the potential for ultrafast and energy-saving non-volatile memory devices. Moreover, twisting the bilayer into a stacking Moiré structure results in a super-paraelectric state, because the ferroelectric order is reversibly broken by DW motion already at ultralow electric fields. These findings offer valuable insights into the behavior and properties of stacking-engineered ferroelectrics, with significant implications for the development of next-generation electronic devices.

Ship energy-saving device: Influence of the scale effect and hull roughness on the resistance reduction effect of an interceptor

Saving energy of ships are key research topics in the shipping industry, and the scale effect of energy-saving devices is a critical issue. Based on the Reynolds-averaged Navier–Stokes method, free-surface and double-body simulations of model- and full-scale ships were performed in this study. The resistance reduction effect and interceptor mechanism were analyzed. In addition, the influence of the scale and roughness effects on the resistance reduction performance of the interceptor was studied. The results showed that the stern flow field was significantly improved after the interceptor was installed, which was mainly responsible for the ship resistance reduction. When the Froude number ≥0.334, the average resistance reduction rates of the model- and full-scale interceptors were 5.67% and 8.71%, respectively. Some differences were observed between the extrapolated results of the resistance reduction effect of the interceptor and the results of the full-scale simulation; therefore, the change in the form factor and the scale effect of the wave-making resistance were considered in the extrapolated method. In addition, with increasing hull roughness, the frictional, viscous pressure, and total resistances of the ship increased, which decreased the resistance reduction rate of the interceptor by 1%–3% and shortened the resistance reduction speed range of the interceptor.