scholarly journals The Energy Conversion behind Micro-and Nanomotors

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 222
Author(s):  
Yingmeng Wang ◽  
Yingfeng Tu ◽  
Fei Peng
Keyword(s):  
Energy Conversion ◽  
Environmental Remediation ◽  
Magnetic Energy ◽  
Mechanical Energy ◽  
External Environment ◽  
Electrical Energy ◽  
Power Devices ◽  
The Past ◽  
Targeted Drug ◽  
Application Prospects

Inspired by the autonomously moving organisms in nature, artificially synthesized micro-nano-scale power devices, also called micro-and nanomotors, are proposed. These micro-and nanomotors that can self-propel have been used for biological sensing, environmental remediation, and targeted drug transportation. In this article, we will systematically overview the conversion of chemical energy or other forms of energy in the external environment (such as electrical energy, light energy, magnetic energy, and ultrasound) into kinetic mechanical energy by micro-and nanomotors. The development and progress of these energy conversion mechanisms in the past ten years are reviewed, and the broad application prospects of micro-and nanomotors in energy conversion are provided.

scholarly journals Properties of Car-Embedded Vibrating Type Piezoelectric Harvesting System

2021 ◽  
Vol 11 (16) ◽  
pp. 7449
Author(s):  
Bo-Gun Koo ◽  
Dong-Jin Shin ◽  
Dong-Hwan Lim ◽  
Min-Soo Kim ◽  
In-Sung Kim ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Energy Conversion ◽  
Mechanical Energy ◽  
Variable Mass ◽  
Electrical Energy ◽  
Engine Block ◽  
Operating Frequency ◽  
Maximum Displacement ◽  
Serial Connection ◽  
Piezoelectric Generator

We investigated the harvesting performance of a double piezoelectric generator, which was embedded into the engine block of a small passenger car. The resonance frequency is approximately between 37 and 52 Hz, where the cantilever showed maximum displacement. In reality, the cantilever has a vibrating characteristic, which dramatically reduces displacement, even when the operating frequency deviates slightly from the resonance frequency. To acquire a large mechanical energy-to-electrical energy conversion, a multiple-piezoelectric generator was employed to absorb the energy even when the vibration switched from a resonance to a non-resonance frequency. In this study, a variable mass box was designed and installed in the engine block of a car. The variable mass box consisted of the serial connection of two masses with different weights. The operating frequency deviated from a resonance to a non-resonance frequency within a few hertz (3~4 Hz); the reduction in vibration was lower, leading to a significant acquisition of the resulting power. This is due to the variable matching of the generator, realized by the action of dual mass. This type of generator was installed in the engine block and produced up to 0.038 and 0.357 mW when the engine was operating at 2200 and 3200 rpm, respectively.

scholarly journals Effective Mooring Rope Tension in Mechanical and Hydraulic Power Take-Off of Wave Energy Converter

2021 ◽  
Vol 13 (17) ◽  
pp. 9803
Author(s):  
Ji Woo Nam ◽  
Yong Jun Sung ◽  
Seong Wook Cho
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Wave Energy Converter ◽  
Hydraulic Motor ◽  
Energy Converter ◽  
The Individual ◽  
Conversion Efficiencies

The InWave wave energy converter (WEC), which is three-tether WEC type, absorbs wave energy via moored cylindrical buoys with three ropes connected to a terrestrial power take-off (PTO) through a subsea pulley. In this study, a simulation study was conducted to select a suitable PTO when designing a three-tether WEC. The mechanical PTO transfers energy from the buoy to the generator using a gearbox, whereas the hydraulic PTO uses a hydraulic pump, an accumulator, and a hydraulic motor to convert mechanical energy into electrical energy. The hydraulic PTO has a lower energy conversion efficiency than that of the mechanical PTO owing to losses resulting from pipe friction and the individual efficiencies of the hydraulic pumps and motors. However, the efficiencies mentioned above are not the efficiency of the whole system. The efficiency of the whole system should be analyzed considering the tension of the rope and the efficiency of the generator. In this study, the energy conversion efficiencies of the InWave WEC installed the mechanical and hydraulic PTO devices are compared, and their behaviors are analyzed through numerical simulations. The mechanics of mechanical and hydraulic PTO applied to InWave are mathematically expressed, and the issues of the elements constituting the PTO are explained. Finally, factors to consider for PTO selection are presented.

Plane PVDF-Foil Modules for Energy Harvesting of Dynamic Weight Forces

2011 ◽  
Author(s):  
Enrico Bischur ◽  
Norbert Schwesinger
Keyword(s):  
Energy Conversion ◽  
Remanent Polarization ◽  
Piezoelectric Effect ◽  
Mechanical Load ◽  
Mechanical Energy ◽  
Electric Energy ◽  
Electrical Energy ◽  
Pvdf Film ◽  
Layer System ◽  
Dynamic Weight

Plane PVDF-foil modules have been developed and successfully tested that generate electrical energy out of the mechanical energy of dynamic weight forces. For instance electrical energy can be generated, if people or vehicles pass such modules on a ground area. This method is based on the piezoelectric effect of stretched PVDF-foil. The energy conversion of the generator modules was investigated with regard to the remanent polarization of the PVDF material. Furthermore, the influence of the PVDF layer system was investigated on the energy conversion. The measured values are compared with values calculated analytically. It was found that a higher remanent polarization of the PVDF material lead to a better energy conversion. Even more electrical energy could be generated, if more PVDF layers were stacked above each other. If the values were normalized on the PVDF volume used in each case, the values of the electric energy were not constant. However, a maximum was observed at n = 21 layers. The measured energy values were higher than calculated values of the longitudinal piezoelectric effect. This could be caused by a simultaneous expansion of the PVDF film in a direction vertical to the direction of the mechanical load. These generator modules could be used as new energy source for emergency lighting, alarm systems, traffic sensors, etc.

scholarly journals Overview of Human Walking Induced Energy Harvesting Technologies and Its Possibility for Walking Robotics

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 86 ◽  
Author(s):  
Hu Shi ◽  
Zhaoying Liu ◽  
Xuesong Mei
Keyword(s):  
Energy Conversion ◽  
Smart Materials ◽  
Electromagnetic Induction ◽  
Mechanical Energy ◽  
Human Walking ◽  
Energy Harvest ◽  
Inertial Element ◽  
The Past ◽  
Overall Efficiency ◽  
Triboelectric Effect

This study is mainly to provide an overview of human walking induced energy harvest. Focusing on the proportion of all energy sources provided by daily activity, the available human walking induced energy is divided with respect to the generation principle. The extensive research on harvesting energy results from body vibration, inertial element, and foot press to convert into electricity is overviewed. Over the past decades, various smart materials have been employed to achieve energy conversion. Generators based on electromagnetic induction or the triboelectric effect were developed and integrated. Small captured power and low overall efficiency are criticized. The concept of human walking energy harvest is extended into the wearable walking robotics using other mediums, such as fluid, to transmit power instead of electricity. By comparison, it is indicated that less energy conversion links are involved in energy regeneration of such applications and expected to guarantee less loss and higher efficiency. Meanwhile, in order to overcome the shortage of relatively low power output, comments are made that the harvester should be capable of adaptation under the condition that the mechanical energy of lower limb and feet is subject to change in different gait phases so as to maximize the collected energy.

Handedness-controlled and solvent-driven actuators with twisted fibers

2019 ◽  
Vol 6 (6) ◽  
pp. 1207-1214 ◽  
Author(s):  
Bo Fang ◽  
Youhua Xiao ◽  
Zhen Xu ◽  
Dan Chang ◽  
Bo Wang ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Conversion Coefficient ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
High Energy ◽  
Polar Solvents ◽  
Start Up

Handedness-controlled actuating systems are constructed from continuous twisted fibers with mirrored handedness, superb flexibility and mechanical robustness, affording impressive start-up torques driven by polar solvents, and controllably outputting rotor kinetic energy, harvesting electrical energy, and delivering mechanical energy with a high energy conversion coefficient.

Key Issues on Flextensional Piezoelectric Energy Harvester Developments

2019 ◽  
Author(s):  
Tian-Bing Xu ◽  
Lei Zuo
Keyword(s):  
Dipole Moment ◽  
Energy Storage ◽  
Energy Conversion ◽  
Energy Harvester ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Storage Efficiency ◽  
Energy Storage Efficiency

Abstract A “33” mode (mechanical stress being in parallel to the electric dipole moment direction) piezoelectric lead zirconate titanate (PZT) multilayer stack-based piezoelectric flextensional energy harvester (PZT-Stacked-FEH) has been developed. Interdisciplinary approaches had been taken to increase the performance of the PZT-Stacked-FEH. First, an elastic flextensional frame for force amplification has been optimally designed to capture more mechanical energy with high energy transition efficiency into the PZT-Stacked-FEH. Second, a “33” mode piezoelectric PZT multilayer stack (PZT-Stack) was employed instead of “31” mode (stress being in perpendicular to the dipole moment direction) single layer piezoelectric component to increase mechanical to electrical energy conversion efficiency and to generate more electrical charges in order to improve energy storage efficiency. With these approaches, the PZT-Stacked-FEH demonstrates excellent performance: 1) a 19% of overall mechanical to electrical energy conversion efficiency was achieved, 2) 48.6 times more mechanical energy was transited into PZT-Stacked-FEH and 26.5 times more electrical power was generated than directly applying force to the PZT-stack, and 3) energy storage efficiency was significantly improved. In this paper, we are focusing on the investigations for the off-resonance mode performance of the PZT-Stacked-FEH through theoretical modeling, prototype development, and experimental studies. A prototype PZT-Stacked-FEH of weight 18 grams was able to generate 666 mW electrical power under 52 Nrms force at 250 Hz, which is much lower than the resonant frequency (936 Hz). At this condition, a 6,600 μF super-capacitor was charged from 0 to 7 V in 1.6 second, at an average rate of 100 mW. Furthermore, 70% of generated appear electrical powers were delivered to matched resistive loads in the investigated regime of frequencies. Finally, the experimental results matched well with theoretical predictions which verified the developed theoretical models.

scholarly journals Thermal energy harvesting system based on magnetocaloric materials★

2019 ◽  
Vol 85 (1) ◽  
pp. 10902 ◽  
Author(s):  
Smail Ahmim ◽  
Morgan Almanza ◽  
Alexandre Pasko ◽  
Frédéric Mazaleyrat ◽  
Martino LoBue
Keyword(s):  
Magnetic Energy ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
The Self ◽  
Optimal Size ◽  
Heat Sources ◽  
Magnetic Forces ◽  
Finite Element Calculations ◽  
Energy Harvesting System ◽  
Magnetocaloric Materials

We numerically study the design of a thermomagnetic generator aimed to convert a heat flow into electrical energy. The device uses the variation of magnetization of a magnetocaloric material (MCM) along a cyclic transformation between the hot and the cold sources. The magnetic energy is transformed into mechanical energy via the magnetic forces and eventually into electrical energy through an electromechanical transducer. Firstly, we work-out the optimal size of the cantilever in order to achieve the self-oscillation of the MCM between the two heat sources. Eventually, using finite element calculations, we compare the efficiency of a piezoelectric transducer (PZT 5a) with that of a set of coils in order to convert the mechanical into electrical energy. The piezoelectrics and the coils recover 0.025% and 0.018% respectively of the available mechanical energy (116 mJ/cm3). The possible strategies to achieve a better performance are discussed in theconclusion.

Regenerative Thermomagnetic Power

1967 ◽  
Vol 89 (3) ◽  
pp. 399-405 ◽  
Author(s):  
E. L. Resler ◽  
R. E. Rosensweig
Keyword(s):  
Energy Conversion ◽  
Specific Weight ◽  
Power Devices ◽  
Electric Moment ◽  
Power Estimate ◽  
Power Cycles ◽  
The Past ◽  
Information Power ◽  
Analogous Manner ◽  
Regenerative Cycle

Thermomagnetic power devices utilize the temperature dependence of magnetic moment to convert heat into organized energy. In an analogous manner thermoelectrostatic devices would utilize changes of electric moment to perform the same function and the analysis of each can be given in a single treatment. This paper, which analytically explores new considerations relevant to these energy conversion methods, is motivated by a search for increased performance. To begin, a basis for the treatment of the thermodynamics of polarizable substances is developed in a manner that stresses material parameters. Explicit thermodynamic functions are then derived corresponding to both a simple and a realistic equation of state. With this information power cycles are devised and evaluation is made of their thermodynamic efficiencies. An optimum regenerative cycle emerges and criteria for its attainment are considered. Finally, a power estimate accounting for thermal irreversibilities predicts the possibility of low specific weight. Using more general conversion techniques than were admitted in the past, the prospect for thermomagnetic and thermoelectrostatic energy conversion is greatly improved.

Feasibility Study on Wave Energy Conversion by a Modified Oscillating Water Column Device

2015 ◽  
Vol 787 ◽  
pp. 8-12
Author(s):  
V.P. Mohandas ◽  
R. Wilbert ◽  
S.S. Saji ◽  
Laiju Lukose
Keyword(s):  
Energy Conversion ◽  
Water Column ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Ocean Waves ◽  
Oscillating Water Column ◽  
Model Studies ◽  
World Energy ◽  
Model Device ◽  
Double Chamber

Energy conversion from ocean waves has become the need of the hour in view of the renewable energy awakening occurring all over the world. Energy conversion by Oscillating Water Column (OWC) concept has become an established technology in converting mechanical energy of ocean waves to electrical energy. But the limitations of OWC concept calls for further research and developments to make the technology commercially an attractive one. In this context Boccotti, the Italian scientist advanced the double chamber concept and the implications of the concept still remains to be investigated through model studies. This paper presents the details of a generic study carried out in a physical model device under regular waves.

scholarly journals Wind power plant resilience

2010 ◽  
Vol 14 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Naim Afgan ◽  
Dejan Cvetinovic
Keyword(s):  
Power Plant ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Wind Power ◽  
Wind Velocity ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Wind Power Plant ◽  
Electricity Cost ◽  
Resilience Index

A wind energy system transforms the kinetic energy of wind into mechanical or electrical energy that can be harnessed for practical use. Mechanical energy is most commonly used for pumping water in rural or remote locations. Electrical energy is obtained by connecting wind turbine with the electricity generator. The performance of the wind power plant depends on the wind kinetic energy. It depends on the number of design parameter of the wind turbine. For the wind power plant the wind kinetic energy conversion depends on the average wind velocity, mechanical energy conversion into electricity, and electricity transmission. Resilience of the wind power plant is the capacity of the system to withstand changes of the following parameters: wind velocity, mechanical energy conversion into electricity, electricity transmission efficiency and electricity cost. Resilience index comprise following indicators: change in wind velocity, change in mechanical energy conversion efficiency, change in conversion factor, change in transmission efficiency, and change in electricity cost. The demonstration of the resilience index monitoring is presented by using following indicators, namely: average wind velocity, power production, efficiency of electricity production, and power-frequency change. In evaluation of the resilience index of wind power plants special attention is devoted to the determination of the resilience index for situation with priority given to individual indicators.

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