Energy-saving Devices Research Articles

Computational Analysis of KCS Model with an Equalizing Duct

In order to minimize carbon emissions and greenhouse gas, the Energy Efficiency Design Index (EEDI) has become a major factor to be considered in recent years in a ship’s design and operation phases. Energy-Saving Devices (ESDs) improve the EEDI of a vessel and make them environmentally friendly. In this research, the performance of an equalizing duct-type ESD installed upstream of a Korea Research Institute of Ships & Ocean Engineering (KRISO) Container Ship (KCS) model’s propeller was investigated by computational fluid dynamics (CFD). Open-source CFD libraries, OpenFOAM, were used for computational analysis of the KCS with and without the ESD to verify the performance improvement. The flow field near the stern region and propulsive coefficients were considered for comparison. The results showed a considerable improvement when an ESD was used on the model. Using different sizes of the duct, the performance of the ESD was also compared. It was observed that with an increased duct size, the propulsive performance was improved.

The design and energy saving effect prediction of rudder-bulb-fin device based on CFD and model test

Recent developments in Computational Fluid Dynamics (CFD) and high-performance computer hardware have made it possible to design Energy Saving Devices (ESDs) using numerical methods. The present work investigates the influence of rudder bulb diameter, thrust fin; span, chord length and angle of attack on propulsive efficiency. In order to increase computational efficiency, a hypothesis was developed and a quick estimate method for design parameters and the optimization procedure. Bare hull resistance, propeller open water performance and interaction of hull-propeller-rudder simulations were carried out using CFD code to solve Reynolds Averaged Navier-Stokes (RANS) equations. A validation study shows a good agreement between the CFD and experimental data. Model tests were carried out using optimum parameters for rudder bulb and rudder attached thrust fins. Comparison of the propulsive efficiency between the ship with the conventional rudder and ship with the optimized rudder-bulb-fin device was done. The model test predicted energy gains of 2.18% compared to 2.63% gains predicted by the CFD method. This study would be useful during design and optimization of rudder-bulb-fin.

Pre- and post-swirl fins design for improved propulsive performances

ABSTRACT Pre- and post-swirl fins-based energy-saving devices (ESD) are designed to improve the propulsive performances of a twin-screw ship. To this aim, BEM and RANSE calculations are employed. Depending on the application, a simple actuator disc model (post-swirl) with radially varying load or a combined BEM/RANSE method for self-propulsion prediction (pre-swirl) are required. Both the approaches are included in a framework for a design by optimization, where systematic variations of the ESD geometry are used to explore the design space and maximize the energy-saving effect of the devices. Considering the particularity of the case selected for the study, results show encouraging improvements that reach a promising 5% in the case of the combined action of both devices.

Differential conductance and spin current in hybrid quantum dot-topological superconducting nanowire

Majorana bound states (MBSs) are topologically protected and follow the non-abelian rather than the usual Fermi–Dirac statistical rule, and then are ideal choice for the preparation of quantum bits in topologically fault-tolerant quantum computing. The MBSs also have significant influences on the electron transport processes in mesoscopic systems and have been studied in the field of fabricating efficient and energy-saving quantum devices. In this study, we investigated electron transport through a hybridized system composed of a topological superconducting nanowire and quantum dot (QD). Effects of MBSs prepared at the nanowire on differential conductance are calculated and analyzed. It is proved that the differential conductance peak near the superconducting nanowires at zero bias reflects the existence of Majorana fermions. By using the Green's function equation of motion method, we found that a pure spin current without the accompany of charge current can be generated by changing the coupling strength between the QD and MBSs, as well as the accumulation of spin heat in the leads. In the presence of Coulomb interaction in the QD, the direction of pure spin current can be changed by modulating the dot energy level and the coupling strength between dot and MBSs.

Stimuli-Induced Reversible Proton Transfer for Stimuli-Responsive Materials and Devices.

ConspectusStimuli-responsive materials have a great potential in various novel photoelectric devices, such as self-adaptive adjustment devices, intelligent detection, molecular computers with information storage capability, camouflage and anticounterfeiting display, various energy-saving displays, and others. However, progress in related areas has been relatively slow because of the lack of high-performance smart materials and the limitations of available reaction mechanisms currently. To address these problems fundamentally, new mechanisms need to be designed and developed, and learning from nature is an effective and intelligent method to achieve this long-awaited target, such as mimicking of proton transfer processes in nature at the molecular/supramolecular level. The stimuli-induced reversible proton transfer system is composed of materials that release or capture protons in response to stimuli and switch molecules that control color and/or fluorescence modulation by protons, and it is applied in stimuli-responsive materials and devices, including bistable electronic/electrochromic devices, electrofluorochromic devices, water-jet rewritable paper, visible-light-responsive rewritable paper, and mechanochromic materials.To help researchers gain deep insight into stimuli-induced reversible proton transfer, we attempted to summarize its reaction mechanism and design principle, and discuss strategies to design and prepare various related stimuli-responsive materials and devices. This Account discusses the different systems in which a color/fluorescence change is induced by the proton transfer process under various stimuli, including electric field, water, light, heat, and stress. Relative very promising applications as well as their performance especially for energy-saving and environmentally friendly devices are then summarized, such as energy-saving bistable electrochromic devices, water-jet rewritable paper, and visible-light-responsive rewritable paper. Meanwhile, we focus on the key influence factors and useful additives for improving the device's performance. At last, challenges and bottlenecks faced by stimuli-responsive materials and devices based on the mechanism of reversible proton transfer are proposed. Moreover, we put forward some suggestions on solving these limitations.These exciting results reveal that smart materials based on the mechanism of proton transfer are extremely attractive and possess great potential in the next generation of energy and resource saving and environmental protection display. We hope that this Account further prospers the field of intelligent stimuli-responsive discoloration materials and next-generation green displays.

Respiratory Impairment, Limited Activity, and Pulmonary Rehabilitation in Patients with Interstitial Lung Disease.

Interstitial lung disease (ILD) is a diverse group of chronic lung conditions characterized by dyspnea, exercise-induced hypoxemia (EIH), and exercise intolerance. Since activity limitations and impaired health-related quality of life (HRQoL) in ILD are similar to those in other chronic respiratory diseases, including chronic obstructive pulmonary disease (COPD), pulmonary rehabilitation is also indicated for patients with ILD. This rehabilitation program mainly comprises exercise training and self-management education. Exercise training is the most important component of pulmonary rehabilitation. It significantly improves dyspnea and enhances exercise capacity and HRQoL in patients with ILD. The standard exercise prescription used for COPD is also effective for ILD. However, considering that disease progression and exercise-limiting factors are different in patients with COPD is necessary. Severe EIH, the adverse effects of corticosteroid administration, and comorbidities often lead to difficulty in employing a sufficient exercise intensity. Some modifications in the exercise prescription for individual patients or strategies to minimize EIH and dyspnea are required to optimize training intensity. Since EIH is common and severe in patients with ILD, supplemental oxygen should be provided. In advanced and more severe patients, who have difficulty in performing exercises, energy conservation techniques and the use of energy-saving devices to improve and maintain the patients' activities of daily living may be effective．.

Sports training monitoring of energy-saving IoT wearable devices based on energy harvesting

In this paper, energy-saving the Internet of Things wearable devices based on energy harvesting used to monitor sports training. The energy sources involved include radiofrequency energy, mechanical energy, and thermal energy. The power management circuit structure designed to match its application with energy harvesting components as the core to ensure that the collected energy can meet the power conditions of electrical equipment. Completed the hardware design of the entire human motion information collection system based on energy-saving IoT wearable devices, first gave the overall design plan of the system, and on this basis, adopted the modular design of the system, and designed the posture measurement separately unit, positioning unit, and data storage and communication unit. Among them, the attitude measurement unit designed according to the different needs in actual use, and the miniature attitude measurement unit and the multi-function attitude measurement unit are designed. The data storage and communication unit designed to ensure data storage and for the reliability of transmission, an offline data storage unit and a Bluetooth remote communication unit designed respectively. The system adopts a modular design, which makes the system more convenient to expand and upgrade, and has better applicability and reliability.

Hydrodynamic State of Art Review: Rotor – Stator Marine Propulsor Systems Design

Abstract The paper covers the important topic of rotor–stator propulsor system design and operation. For the stand-alone marine screw propeller, both the design criteria for loading distribution and the theoretical efficiency limits are well described in the basic literature. This is in contrast to the combined propulsor system like a propeller cooperating with a pre-swirl device. The paper describes the current state of the art, summarising results obtained by various researchers by installing energy-saving devices on particular vessels. The design methods utilised are briefly outlined, with the main characteristics underlined. Rough analysis of the gathered data confirms the expected trend that a higher efficiency gain due to ESD installation is possible for a higher propeller loading.

Coupled Level-Set and Volume of Fluid (CLSVOF) Solver for Air Lubrication Method of a Flat Plate

With the implementation of the energy efficiency design index (EEDI) by the International Maritime Organization (IMO), the goal of which is to reduce greenhouse gas (GHG) emissions, interest in energy saving devices (ESDs) is increasing. Among such ESDs are air lubrication methods, which reduce the frictional drag of ships by supplying air to the hull surface. This is one of the efficient approaches to reducing a ship’s operating costs and making it environmentally friendly. In this study, the air lubrication method on a flat plate was studied using computational fluid mechanics (CFD). OpenFOAM, the open-source CFD platform, was used. The coupled level-set and volume of fluid (CLSVOF) solver, which combines the advantages of the level-set method and the volume of fluid method, was used to accurately predict the air and water interface. Rayleigh–Taylor instability was simulated to verify the CLSVOF solver. The frictional drag reduction achieved by the air lubrication of the flat plate at various injected airflow rates was studied, and compared with experimental results. The characteristics of the air and water interface and the main factors affecting the cavity formation were also investigated.

Giant spin torque efficiency in single-crystalline antiferromagnet Mn2Au films

Antiferromagnetic (AFM) materials have attracted wide attention in spin-orbit torque (SOT)-based spintronic due to its abundant spin-dependent properties and unique advantage of immunity against external field perturbations. To act as the charge-to-spin conversion source in energy-saving spintronic devices, it is of great importance for the AFM material to possess a large spin torque efficiency (ξDL). In this work, using the spin torque ferromagnetic resonance (ST-FMR) technique and a Mn2Au/NiFe(Py) bilayer system, we systemically study the ξDL of AFM Mn2Au films with different crystal structures. Compared with polycrystalline Mn2Au with effective ξDL < 0.051, we show a much larger ξDL of ~0.333 in single-crystal Mn2Au, which arises from the large spin Hall conductivity instead of electrical resistivity. Moreover, with a further contribution of interfacial effects, the effective ξDL of single-crystalline Mn2Au/Py system increases to 0.731, which is more than two times larger than the value of ∼0.22 reported for the Mn2Au/CoFeB system. By utilizing the large ξDL of Mn2Au in a perpendicularly magnetized MnGa/Mn2Au system, energy-efficient deterministic magnetization switching with a current density at ~106 A cm−2 is achieved. Our results reveal a significant potential of Mn2Au as an efficient SOT source and shed light on its application in future AFM material-based SOT integration technology.

Energy-Saving Devices in Ship Propulsion: Effects of Nozzles Placed in Front of Propellers

The hydrodynamic effect exerted by a nozzle placed in front of a KP505 propeller on the propulsive performances is studied by using extensive numerical simulations. The influence of a NACA 0015 nozzle with a chord length of 0.3 of the propeller diameter, D, mounted at 0.2 D in front of the propeller plane is studied for a various range of relevant nozzle diameters and different angles of attack. A detached eddy simulation (DES)-based hybrid technique implemented on the ISIS-CFD finite volume solver of the Numeca’s FineTM/Marine environment is proposed to fit the purpose. Systematically conducted simulations have proven that the net thrust reflecting the overall drag, which includes the nozzle, depends on the duct size. The duct presence determines two regions of the inflow into the propeller. One is the inner region of the nozzle where the high-speed flow exists because of the contraction of the duct. The other is the outer region of the nozzle where the flow decelerates due to the duct wake. Lower- and higher-pressure coefficients on the suction and pressure sides, cover a significantly wider area than those of the case without the nozzle, leading therefore to greater thrust and torque. The existence of a critical attack angle for which the magnitude of the relative axial force becomes maximum for the smallest nozzle diameter has been noticed.

Hydrophobic fluorinated colloidal photonic crystals for heterogeneous aggregated cluster encoding and energy-saving applications

The construction of high-quality colloidal photonic crystals (CPCs) for optoelectronics, energy and biological applications, featuring the viable and effective self-driven assembly route, still remains a challenge. Herein, we demonstrate the efficient self-assembly of hydrophobic fluorine-containing poly(trifluoroethyl methacrylate) (PTFEMA) CPCs via hydrophobic force for heterogeneous aggregated cluster encoding and photoluminescence enhancement of liquid crystal display (LCD). The CPC films with periodic arranged structure self-assembled through the hydrophobic terminals (-CF3) display tunable brilliant structural color and large-area crack-free morphology. Moreover, taking advantage of PTFEMA emulsion and superparamagnetic Fe3O4 nanoparticle suspension as two discontinuous phases, Janus microbeads are fabricated by the triphase microfluidic technology, which are subsequently constructed into heterogeneous aggregated clusters that perform multiple structural color signals for the optical encoding. Eventually, the PTFEMA CPC film serves as the photoluminescence enhanced film to significantly elevate the photoluminescence (PL) intensity of CdSe@ZnS quantum dots by ca. 11 folds in an LCD device. The novel PTFEMA CPCs may offer the alternative opportunities for optical encoding towards sensing, anticounterfeiting and information storage, as well as the energy-saving optoelectronic devices.

ПРОЕКТУВАННЯ СИЛОВИХ ТРАНЗИСТОРНИХ ПЕРЕТВОРЮВАЧІВ ЕНЕРГІЇ ДЛЯ СИСТЕМ АВТОМАТИЗОВАНОГО ЕЛЕКТРОПРИВОДУ ПОСТІЙНОГО СТРУМУ

Purpose. One of the integral parts of modern mechatronic motion modules, where electric motors provide the conversion of electrical energy into useful mechanical action, are power semiconductor converters. At the current stage of industrial development, the use of energy converters as a part of a fully controlled semiconductor switches opens wide opportunities for the development and implementation of highly efficient resource- and energy-saving devices. Methodology. Two types of converters are widely used in automated DC electric drive systems: controlled thyristor rectifiers and pulse-width DC converters, the principle of operation of which is based on the key mode of operation of the regulating semiconductor, which periodically connects the source voltage to the output circuit. The paper presents a laboratory sample of a power semiconductor DC energy converter, which can ensure reliable motor operation in both motor and braking modes. Results. The presented transistor energy converter consists of two main parts: the first part performs the main role – control, and it includes a control unit, a microcontroller, and a device for displaying current information. The second part is a power module, which includes the necessary power supply modules, control drivers and power transistor switches of the converter. To obtain high quality transients of the electric drive system, the circuit is equipped with additional sensors of current, voltage and speed, which takes part in the formation of the control signal and in the protection systems against overvoltage and current jumps. Practical value. The paper substantiates the parameters of the components and proposes developed technical solutions for the construction of a microprocessor control system for a transistor DC energy converter. It is shown that in order to ensure a constant generator mode in automated electric drive systems, where the primary energy converter is an uncontrolled rectifier, it is expedient to install an energy discharge circuit in the DC link. References 18, figures 14.

Application and research of energy-saving lighting devices in engineering networks

This system allows to control the flow of light by adding or subtracting light. Such actions can be performed via a remote control. This system is quite complex, but very convenient. With the help of this system, a special sensor that detects the level of light can be installed and it is possible to provide automatic lighting of lamps at the desired level. The article discusses the support of energy-saving systems in the technical regulation of public utilities, in particular, metrological regulation of ballast effect control.

A sub-1V, microwatt power-consumption iontronic pressure sensor based on organic electrochemical transistors.

Wearable and implantable pressure sensors are in great demand for personalized health monitoring. Pressure sensors with low operation voltage and low power-consumption are desired for energy-saving devices. Organic iontronic devices, such as organic electrochemical transistors (OECTs), have demonstrated great potential for low power-consumption bioelectronic sensing applications. The ability to conduct both electrons and ions, in addition to their low-operation voltage has enabled the widespread use of OECTs in different biosensing fields. However, despite these merits, OECTs have not been demonstrated for pressure sensing applications. This is because most OECTs are gated with aqueous electrolyte, which fails to respond to external pressure. Here, a low power-consumption iontronic pressure sensor is presented based on an OECT, in which an ionic hydrogel is used as a solid gating medium. The resultant iontronic device operated at voltages less than 1 V, with a power-consumption between ~ 101-103 μW, while maintaining a tunable sensitivity between 1 ~ 10 kPa-1. This work places OECTs on the frontline for developing low power-consumption iontronic pressure sensors and for biosensing applications.

Band-Gap Sensitived Seebeck Effect in Heavy Group-IV Monolayers

We have systematically investigated the spin- and valley-dependent Seebeck effect in irradiated heavy group-IV monolayers including silicene, germanene, and stanene by means of semi-classical Boltzmann equation in diffusive regime. Due to the interplay of strong intrinsic spin-orbit coupling, perpendicular electric field, and off-resonant light field, the temperature-driven spin and valley conductivity can be controllable effectively. Except for numerical results, the amplitude of Seebeck coefficient is analyzed and found to be in direct proportion to the band gap at high temperature. It supplies a flexible method to modulate the Seebeck effect. In addition, we have compared the thermoelectric transport properties of different group-IV materials and found that the figure of merit shows great enhancement from silicene to stanene. These findings are excepted to provide a platform for the heavy group-IV materials in future spin–valley thermal and energy-saving devices.

ПОВЫШЕНИЕ ТЕХНИЧЕСКОГО УРОВНЯ ГИДРОПРИВОДА МАНИПУЛЯТОРОВ АВТОСОРТИМЕНТОВОЗОВ

The main requirements for hydraulic equipment of forest transport machines of manipulator type are revealed. It is established that the main drawback of the used hydraulic drives of manipulators is their increased power and high energy consumption. The main ways of increasing the technical level of hydraulic manipulators of forest transport vehicles are considered. The constructive optimization and improvement of the hydraulic drive mechanism for lifting the boom and turning the column of the manipulator is justified. New designs with the use of hydro-mechanical dampers and energy-saving devices are proposed. As energy-saving devices, it is proposed to use a hydraulic accumulator. The main advantages of the design, which are to increase the reliability and expand the technological capabilities of hydraulic manipulators forest transport machines. The principles of influence on the hydraulic system that reduce the pressure in the piston group and reduce energy consumption are substantiated. The proposed energy-saving hydraulic drive reduces the maximum pressure during braking to 3 MPa. The recovery energy when the column is rotated is 25 % of the energy consumed. The diameter of the dampener's lockable cavities should be 48 mm with the internal diameter of the dampener 65 mm. Minimal changes in the design are achieved to increase the technical level of the hydraulic drive of manipulators of forest transport machines and its competitiveness among existing analogues.

All-electrical switching and electrothermo-optical response of a tristable smectic-A liquid crystal

A unique switching mechanism in the smectic-A (SmA*) phase involving textural change between any two among the planar, homeotropic and focal conic states is investigated. Exploiting the temperature-dependent textural transition characteristics of a SmA* liquid crystal (LC), we proposed a multi-stable switching scheme relying on AC voltage to induce the dielectric effect and pseudo-dielectric heating. This mechanism exhibits desirable properties for LC cells with anti-parallel planar surface treatment. Compared with the electrical operation mode of conventional SmA devices, the optical states enabled by this approach show superior qualities in both transmittance and haze value. The revealed features, including the in-phase switching, tunable operating temperature and excellent optical performance, show great potential for applications in smart glass and other energy-saving devices.

Influence of a pre-swirl stator and rudder bulb system on the propulsion performance of a large-scale ship model

With the implementation of an energy efficiency design index, energy-saving devices (ESDs) have received increasing research interest. In this study, experimental and numerical analyses were performed on a 25-m long ore carrier model to investigate the working mechanism of ESDs comprising a pre-swirl stator and a rudder bulb. The interactions between the hull, propeller, rudder, and ESDs were observed to have a positive effect on the propulsion performance of the large-scale ship model. To elucidate the effects, self-propulsion tests were conducted at sea to determine the thrust and torque coefficients. The sliding mesh method was used to perform numerical simulations of the large-scale ship model for unsteady multiphase flows with different inflow speeds. The wake field at the stern and the pressure distribution on the vessel surface were analysed to investigate the energy-saving mechanism. The results showed that ESDs can effectively ameliorate the propeller slipstream and have a positive interference effect on the large-scale hull. The average gain of the ESDs relative to no-ESDs was up to 3%.

Integrated Design of Solar Energy Utilization and Building Based on PLC

At present, fossil energy consumption still occupies a dominant position in China’s energy consumption structure, and problems such as low energy consumption efficiency, high degree of carbonization and large environmental pollution persist for a long time. Under the background of advocating environmental protection and energy saving, the combination of solar energy and building is the inevitable trend of building energy saving development, and the integrated design of solar energy and building has become a concern of the architectural circles. With the deepening of people’s understanding of environmental problems and the further deterioration of energy problems, more and more buildings begin to use clean and energy-saving solar energy devices. At present, the construction and development of urban residential buildings in China are mainly multi-storey and high-rise buildings. Therefore, higher requirements are put forward for the application form and scale of solar water heating system in residential buildings. In this paper, according to the current situation of solar energy utilization in buildings in China, based on PLC (programmable logic controller), the paper puts forward some suggestions to promote the integrated design of solar energy buildings.