Energy-saving Device Research Articles

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.

An investigation into the gate rudder system design for propulsive performance using design of experiment method

ABSTRACT The Gate Rudder System (GRS) is an innovative energy-saving device integrating the steering and propulsion of ships. Despite demonstrated potential, optimal GRS design remains underexplored. This study used a Design of Experiment (DoE) approach to investigate the sensitivity of key design variables of the GRS on the ship's powering performance. Computational Fluid Dynamics (CFD) analysis was employed to calculate the respective flow variables at each design point, and the most effective geometrical parameter was identified as the rudder angle based on the correlations. Surprisingly, the analyses revealed that the best powering performance was not observed with the highest rudder thrust force generated. Instead, the optimal design was found to be one that maximizes the overall energy savings by achieving the most favorable interaction between the propeller, hull, and GR. High-fidelity CFD validates results. This study bridges the gap in GRS design for powering efficiency, contributing to technology's performance optimisation.

Comparison of Performance of Straight- and V-shaped Vanes Applied as Energy Saving Device to High-speed Boats

Hull Vane® is a device, generally utilizing a straight vane, installed horizontally near the stern of a vessel below the water surface and oriented in the transverse direction of the vessel with the purpose to save fuel consumption and to increase the vessel’s comfort. Because the bottom-hull form of a ship is generally curved, a non-straight vane may be more effective than a straight one when applied as Hull Vane®. The purpose of this study is to investigate the effectiveness of a V-shaped vane when applied as Hull Vane® on a 31 m high-speed crew boat. The study utilizes a computational fluid dynamics (CFD) method. CFD results show that the Hull Vane® decreased the bow-up trim of the boat, affected the boat’s wetted surface area, and decreased the height of the waves generated by the boat. The wave-height reduction due to the V-shaped Hull Vane® is larger than the straight Hull Vane®. Further, the Hull Vane® significantly reduced the total resistance of the boat at Froude number Fr = 0.34 with a larger reduction resulted from the V-shaped Hull Vane® (25.09% reduction for the straight vane and 30.75% reduction for the V-shaped vane). The observed resistance reduction decreased with increasing speed, ascribed to a too-large vane’s lift. The V-shaped Hull Vane® is more effective than the straight Hull Vane® in reducing the total resistance of the boat.

Development of Thermoelectric Generator for Energy Saving Device Using Exhaust Waste Heat in Patrol Boat

Development of Thermoelectric Generator for Energy Saving Device Using Exhaust Waste Heat in Patrol Boat

SISTEM KONTROL PERANGKAT LISTRIK HEMAT ENERGI PADA BANGUNAN BERBASIS BERBASIS INTERNET OF THINGS (IoT)

Accidents caused by improper use of electricity have been widely aired on TV media and On Line media. To prevent this, it is hoped that people who install electrical installations must be certified and are expected to know about how IoT-based energy-efficient control devices work. This research aims to: 1) To create an Energy-Saving Electrical Device Control System Software in IoT-Based Buildings that functions to control the use of electrical energy in a building with the help of a Smartphone, 2) produce an Energy-Saving Control System Device using the software that has been created, 3) To create an Interface and Application of the Internet Of Things (IoT) Based Energy Saving Control System device with the help of a Smartphone that functions to control electrical devices in buildings, both from a short distance, and remotely. Data collection in this study uses interview techniques with control experts, literature techniques, and direct measurement techniques of the control devices used. The data analysis method used in this research is the logical method, based on the Internet of Things (IoT) based control system. The results showed that: 1) The Internet Of Things (IoT)-based Energy Saving Control System Software created has functioned properly, this is evidenced by the functioning of all control systems, both in the safety system (MCB), as well as for various controlled loads, 2). The Internet Of Things-based Energy Saving Control System device made, has functioned properly, this is evidenced in the research trial using a Smartphone, 3). Interface and Control System Applications based on the Internet of Things have functioned properly, because they have been able to control electrical equipment devices contained in a building according to design.

CFD-based hull-engine-propeller matching study after retrofitting propeller boss-cap-fin (PBCF)

Propeller boss-cap-fin (PBCF) is an energy-saving device that can improve propeller propulsion efficiency. The addition of PBCF influences both the propeller characteristic and the engine behaviour. However, there is limited research on the integrated design of PBCF and ship propulsion system.In this paper, Computational Fluid Dynamics (CFD) methods are used to simulate the PBCF performance and the interactions between PBCF and the propeller. The Wageningen B series propellers are used to investigate the PBCF geometry parameters effects on the propeller hydrodynamics. An influence fraction of PBCF is defined and used to modify the propeller open-water characteristic, which is used in the hull-engine-propeller matching process. Then, PBCF is added into the matching process as a module to realize the hull-engine-propeller and PBCF matching. Multiple groups of matching tests with PBCF are set up to investigate its influences on the matching characteristics.In summary, a new ship-propeller-engine matching method for propellers with PBCF has been investigated in this paper, and systematic insights of the influence of PBCF on the propulsion system are provided. The interactions between PBCF and matching characteristic parameters are important to ship propulsion system design and comprehensive evaluation of PBCF performance.

Freezing-resistant poly(N-isopropylacrylamide)-based hydrogel for thermochromic smart window with solar and thermal radiation regulation

Adaptive regulation of solar and thermal radiation by windows in diverse (hot and cold) climates is essential to reduce building energy consumption. However, conventional hydrogel-based thermochromic smart windows lack thermal radiation regulation, and have difficulty to combine high solar regulation with excellent freezing resistance. It is challenging to integrate the above performance into one hydrogel-based thermochromic window. Here, we firstly prepared poly(N-isopropylacrylamide-co-N, N-dimethylacrylamide)/ethylene glycol (PNDE) hydrogels with tunable and excellent freezing resistance (below −100 °C) by adding the anti-freezing agent ethylene glycol, and assembled PNDE hydrogels, polyvinylidene fluoride and polymethyl methacrylate-silver nanowires panels into a freezing-resistant smart window with solar and thermal radiation regulation (STR). PNDE hydrogels had an excellent thermochromic performance with luminous transmittance (Tlum) of 89.3 %, solar regulation performance (ΔTsol) of 80.7 % and tunable phase change temperature (τc, 22–44 °C). The assembled STR window showed high Tlum of 68.2 %, high ΔTsol of 62.6 %, suitable τc of ∼30 °C and freezing resistance to low temperature of −27 °C. Moreover, the different thermal emissivity (0.94 and 0.68) of the two sides of the STR window gave it the ability of radiative cooling in hot climates and warm-keeping in cold climates. Compared to the conventional thermochromic windows, the STR window promotes heat dissipation in hot conditions while reduces heat loss in cold conditions and is applicable to diverse climates, which is a promising energy-saving device for reducing building energy consumption.

Polymer-Stabilized Liquid Crystal Films Containing Dithienyldicyanoethene-Based Chiral Photoswitch: Multi-Modulation for Environment-Adaptative Smart Windows.

A polymer-stabilized liquid crystal (PSLC)-based environment-adaptative smart window with multi-modulations is demonstrated. This PSLC system contains a right-handed dithienyldicyanoethene-based chiral photoswitch and a chiral dopant, S811, with opposite handedness, of which the reversible cis-trans photoisomerization of the switch can drive self-shading of the smart window under UV light stimulus because of the transition from nematic phase to cholesteric one. With the assistance of solar heat, the opacity of the smart window can be deepened because the heat promotes the isomerization conversion rate of the switch. This switch has no thermal relaxation at room temperature, therefore, the smart window exhibits dual stabilization: transparent state (cis-isomer) and opaque state (trans-isomer). Moreover, the incident intensity of sunlight can be regulated by an electric field, which allows the smart window to adapt to some specific situations. Such an energy-saving device can be used in buildings and vehicles to control indoor temperature and adapt to the required ambiance.

Revealing the influence of temperature and moisture content on electrophysical parameters of raw apple materials

Additional heating of fruit raw materials in the drying process by direct passage of alternating electric current makes it possible to intensify the dehydration process by 3–5 times.
 The amount of added thermal energy during direct electric heating depends, first of all, on the value of the specific electrical resistance of the raw material. Therefore, the list of necessary properties of the material must necessarily include the specific electrical resistance of the raw material as an integral indicator.
 During drying with additional direct electric heating, the concentration of dry soluble substances, which directly depends on the moisture content of the studied raw material, and its temperature change throughout the drying time. This indicates a change in specific electrical resistance during the dehydration process. It was determined that the initial resistivity of apples before drying at a temperature of 20 °C and a moisture content of 8 kg/kg is within 195–220 Ohm•m, which indicates the high conductivity of the material.
 With a decrease in moisture content from 8 to 6 kg/kg, the specific electrical resistance of the raw material decreases by 25–30 % compared to the initial values. With a further decrease in moisture content below 6 kg/kg, the electrical resistivity of the raw material begins to gradually increase.
 At the same time as the temperature rises, there is a significant decrease in specific electrical resistance. When heating raw materials from 25 to 55 °C, the value of specific resistance decreases by 10–13 times.
 The equation of the dependence of the specific electrical resistance of apple raw material on its moisture content and temperature for the studied apple varieties was obtained.
 The obtained results of the change in the value of the specific resistance provide the necessary data for the development of an energy-saving technological device for drying fruits and the selection of optimal processing conditions in compliance with quality indicators

Design optimization of connector on ship interceptor

Currently, research on an energy-saving device only focuses on the effective operation of this device. Structural assessment is needed to evaluate the reliability of the interceptor in operation conditions. In this study, 25 mm thick interceptors are evaluated using the finite element method to find an optimized position of the bolt connector. The simulation shows that a smaller size of bolt connector leads to a higher maximum stress of interceptor. Based on the position of the bolt connector, it has a similar pattern in every bolt size. Overall, the best choice to install this device on the boat is between 140 mm and 240 mm of bolt distance. This distance is advised for installing an interceptor in the existing boat structure to avoid weakening the boat structure.

Analytical Analysis of a Novel Flux Adjustable Permanent Magnet Eddy Current Coupling with Double-Sided Conductor

The permanent magnet eddy current coupling is widely used in fan and pump equipment as an energy-saving speed control device. The traditional coupling speed adjustment method occupies too much axial space, limiting its application in the process of upgrading old equipment. This paper proposes a novel flux adjustable permanent magnet eddy current coupling with a double-sided conductor to reduce the coupling axial distance while increasing the coupling output torque. The relative angle between the permanent magnet rings is controlled to adjust the output torque, and the double-sided conductor structure is used to improve the output torque. The working principle of the proposed design is illustrated. An analytical model for estimating the regulation performance of the proposed structure is proposed, which introduces the regulated reluctance into the equivalent magnetic circuit method. Based on this model, the expressions for magnetic flux density, eddy current density, and output torque are established. Finally, the accuracy of the analytical model was verified by the 3D finite element method, and the parameter sensitivity analysis was performed. The analysis results show that this device can achieve a relatively large range of output torque regulation under the condition of a fixed air gap, and the output torque is greatly improved by adopting a double-sided conductor structure.

New methodological approach to calculations for design of energy-saving device for heating water intended for livestock watering

Relevance. The development and use of new tools and technologies aimed at energy saving in agriculture has been and remains an urgent task. The use of non-traditional and renewable energy sources has become very popular. An advanced role in this direction is acquired by the use of heat released by cattle.Methods. It is assumed that due to the free heat, which is directed to the disposal of the livestock premises, heating will occur, for which a new device for heating water has been developed. Based on the results of calculations and observations, it was decided that the device for water heating will be placed in the place where the air temperature in the livestock premises reaches maximum values. There are a number of issues that need to be solved. One of them is an important part of the design of a new heating device — this is the calculation of its constructive parameters.Results. It is necessary to take into account many factors that affect the heat generation of cows, their drinking conditions, possibility of the installation of the heat exchanger to affect the ventilation in premises, its heating capacity. The calculation of these parameters will make it possible to evaluate in real conditions of use of water heating device, working due to the release of heat from cattle. Its use will reduce the consumption of electric energy, which is used to heat water intended for cows.

Study on the Influence of Gradient Wind on the Aerodynamic Characteristics of a Two-Element Wingsail for Ship-Assisted Propulsion

It is well known that sail-assisted propulsion works under gradient wind conditions in the atmospheric boundary layer, and is an energy-saving device for fuel consumption. In order to study the aerodynamic characteristics of a wingsail in the atmospheric boundary layer above sea level, a transition SST turbulence model was used for numerical simulation of the wingsail with uniform and gradient wind conditions. We concluded that gradient wind conditions can delay the stall caused by an increased angle of attack. This is because the airflow on the suction surface of the wingsail in the spanwise direction exerts an acceleration towards the top of the wingsail. At the same time, supplementary airflow compresses the separated vortex, thus delaying the stall of the two-element wingsail. Under gradient wind conditions, the flow separation of the wingsail develops rapidly in the stall angles. Once a flat separation vortex is formed at the trailing edge of the wingsail, with the slow increase of flap deflection angle, flow separation rapidly expands and a deep stall occurs. Therefore, a small change of the flap deflection angle in the near-stall angles may lead to a deep stall of the wingsail, which should be avoided in engineering applications. Finally, the influence of the average speed of the gradient wind on the aerodynamic performance of the two-element wingsail was analyzed.

Application status and development trend of air-source heat pump drying unit

In order to create a suitable environment and improve the quality of life of the people, the country has paid more attention to the problem of environmental pollution. The drying and drying process of materials accounts for a large part of the total energy consumption. Air source heat pump is an energy-saving device that consumes a small amount of high energy to improve the quality of low energy through thermal cycle, and has been widely used in many fields. The air-source heat pump drying unit can provide efficient drying technology, which is gradually applied in many fields such as production and manufacturing, grain processing, fruit and vegetable drying, etc. In this paper, the working principle of the air-source heat pump drying unit is briefly described, and then its application status in the fields of grain processing, fruit and vegetable planting, stadium reconstruction and so on is described. Finally, the development trend of the air-source heat pump drying unit is proposed from the perspective of technical process optimization.

The GATERS Project – An innovative way of retrofitting ships for greener and safer operations

This paper presents the first-year activities of the H2020 Innovation Action project GATERS for greener propulsion of ships using an innovative retrofit energy-saving and steering device, the Gate Rudder System (GRS). One of the project's main aims is to retrofit a target coastal vessel with a GRS for the first time and demonstrate its effectiveness. The target vessel is the existing 6400 DWT general cargo ship (MV Erge), currently fitted with a high-lift conventional rudder system (CRS), which a retrofit GRS will replace in GATERS as one of the project aims. This paper provides a background of GRS technology and the project motivation, including a brief project overview. The details of the retrofit task involving the design of the main GRS components and estimated power-saving are also reported in the paper. The vessel is scheduled to be retrofitted in December 2022 for demonstration and further performance monitoring.

Analysis of studies of work processes of energy-saving hydraulic drives and devices of highly loaded technological machines and equipment

The analysis of studies of the work processes of energy-saving hydraulic drives and devices was carried out in order to identify effective ways to reduce the dynamic loading and energy intensity of highly loaded technological machines and equipment. When studying the working processes of an energy-saving pneumohydraulic fifth wheel coupling of a timber tractor with a trailer, it was found that the recuperated power was 5.1-5.9 kW, and the average acceleration of the semi-trailer was 0.8 ... 0.81 m/s2. The energy-saving device of the Amkodor 208V front loader, which includes two torsion springs installed between the frame and the boom, reduces energy costs by 26%. The paper presents studies on energy saving during the operation of a hydraulic press with a pump-accumulator power supply. The results of studies of the energy-saving hydraulic drive of a forest manipulator and a chokerless skidding grip are presented. The energy-saving hydraulic drive of the manipulator column makes it possible to reduce the energy consumption of the column rotation by 25% and increase the productivity of the manipulator by 14%, and the chokerless grip hydraulic accumulator stores power in the range of 1.7 ... 2.1 kW. It is concluded that it is expedient to conduct further studies of the dynamics of energy-saving hydraulic drives of load-lifting mechanisms of manipulators of heavily loaded forestry vehicles.

Development and Testing of the Thermoelectric Thermal Energy Conversion Device in the Conditions of Existing Aluminum Production

The aim of the work is to develop an energy-saving device that provides the conversion of thermal energy into electrical energy. The design and materials of the thermoelectric converter unit, consisting of 12 thermoelectric converter modules, a cooling radiator and a switching unit, were developed and selected. Based on the test results, the zone of the maximum temperatures in the section of the gas duct recommended for the installation of a gas cooling module using a thermoelectric converter was determined. The technology for cooling gases with the help of a thermoelectric converter was tested on the site located in front of the experimental heat exchanger. An assessment of the efficiency of the conversion of heat into electrical energy was conducted using the design of the thermoelectric converter unit, based on thermoelectric modules TGM 127-1.4-1.2. It was determined that the device is capable of generating electricity stably for production needs. The data obtained showed that, at a temperature difference of 75-80 °C between the wall surface of the gas duct section and the coolant, the power of one thermoelectric converter block of the gas cooling system reaches 9 W.

A probabilistic method to evaluate bow foils for realistic seas and shipping routes

To improve ship efficiency and reduce CO2 emissions, the use of renewable based energy saving devices is an emerging field. By harnessing the ambient wave energy, ship bow mounted foils can serve as an energy saving device (ESD), reducing the added resistance in waves and generating an additional thrust. This paper presents a methodology to predict the efficiency of bow foils over various regions, seasons and ship routes. The results show that ship length significantly influences the effectiveness of bow foils with respect to differing regions worldwide. The percentage foil retraction is also shown to be a significant factor in operating bow foils with a large variation depending on ship heading and encountered sea state. The presented method, which could be implemented for the assessment of future bow foil designs, provides a holistic approach to evaluate bow foils for route and ship specific energy savings.

Design and optimization of rudder bulb based on CFD and genetic algorithm

With the mandatory implementation of Energy Efficiency Design Index (EEDI), higher requirements are put forward on the energy-saving capacity of ships. The fact that 15–30% propulsion energy is lost in the wake inspires people to exploit the measures for improving energy-saving capacity of ships to meet the EEDI requirements by recovering the lost energy, such as through rudder bulb. Thus, the design and optimization of rudder bulb appears to be particularly important. This paper aims to propose a design and optimization framework for rudder bulb to find a high-performance energy-saving device suitable for the propulsion system of a ship. A Computational Fluid Dynamics (CFD) method is applied to predict the hydrodynamic performance of the propulsion system with rudder bulbs, and validation and gird uncertainty analysis are conducted for simulation of propeller open-water test. Then, a Design of Experiment (DOE) method is used to conduct sensitivity analysis of design variables, and a Genetic Algorithm (GA) approach is adopted in search of the optimal design of rudder bulb. The results of the propulsion system with different rudder bulbs are presented and analysed. It shows that a 3.66% increase in efficiency is achieved by the optimal rudder bulb design via GA approach.

The Effect of Mewis Duct Energy Saving Device to Propeller Performance

Installation of ESD (Energy Saving Device) can improve ship propulsion performance. Mewis Duct is one type of ESD (Energy Saving Device) multi-component device that combines nozzle and fin into the nozzle. The structure can minimize losses due to small losses at the ship's stern and rotational losses or loss of thrust in the slipstreams area. Mewis Duct can reduce power by about 3-8% and increase thrust on the propeller by about 2-5%. This study aims to improve the performance of the INSEAN e779a propeller type using Mewis Duct. The modified Mewis ducts are the number of fins four, five, six asymmetrical and four symmetrical fins using the computational fluid dynamics (CFD) approach. The CFD code is based on the RANS (Reynolds - Averaged Navier Stokes) equation with the turbulent model is k-ε. This study found that installing Mewis duct as ESD in a ship increased the propeller thrust by 3-5% and the torque by 3-4%.