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.

A Novel Piezoelectric Multilayer Stack Energy Harvester With Force Amplification

2013 ◽  
Author(s):  
Wanlu Zhou ◽  
Lei Zuo
Keyword(s):  
Energy Conversion ◽  
Energy Harvester ◽  
Proof Mass ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Power Delivery ◽  
Delivery Ratio ◽  
Resistive Load

A piezoelectric lead zirconate titanate (PZT) multilayer stack flextensional energy harvester (PZT-Stack-FEH) was designed and characterized in this paper. An elastic flextensional frame for force amplification was optimally designed to transmit more mechanical energy with high efficiency to the PZT-Stack-FEH. Instead of 31-mode single layer piezoelectric component, a 33-mode piezoelectric PZT multilayer stack was employed to increase mechanical-to-electrical energy conversion efficiency. The power delivery ratio of the electrical power dissipated by resistive load over the total generated electrical power from PZT stack was studied. Theoretical analysis and experiments were carried out. The experiment results show that the mechanical-to-electrical energy conversion efficiency of the PZT-Stack-FEH is 19%, 48.6 times more mechanical energy can be transmitted to PZT-Stack-FEH, and 26.5 times more electrical energy can be generated by using the PZT-Stack-FEH than directly applying force to the PZT multilayer stack. The maximum power delivery ratio can attain 70% when the resistive load matches the impedance of piezoelectric stack. The power generation performance of the PZT-Stack-FEH with a proof mass was also studied. Experiment results show that he peak power/acceleration can attain 2400mW/g when the PZT-Stack-FEH is connected with a proof mass of 200 grams and 3280 mW/g with a proof mass of 500 grams.

Highly efficient functional GexPb1−xTe based thermoelectric alloys

2014 ◽  
Vol 16 (37) ◽  
pp. 20120-20126 ◽  
Author(s):  
Yaniv Gelbstein ◽  
Joseph Davidow
Keyword(s):  
Energy Conversion ◽  
Fuel Consumption ◽  
Conversion Efficiency ◽  
Thermoelectric Materials ◽  
Waste Heat ◽  
Electrical Power ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Efficient Implementation ◽  
Thermoelectric Devices

Methods for enhancement of the direct thermal to electrical energy conversion efficiency, upon development of advanced thermoelectric materials, are constantly investigated mainly for an efficient implementation of thermoelectric devices in automotive vehicles, for utilizing the waste heat generated in such engines into useful electrical power and thereby reduction of the fuel consumption and CO2 emission levels.

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.

Study of a magnetic SMA-based energy harvester using a corrugated structure

2021 ◽  
pp. 1045389X2098390
Author(s):  
Omid Safari ◽  
Mohammad Reza Zakerzadeh ◽  
Mostafa Baghani
Keyword(s):  
Smart Materials ◽  
Energy Harvester ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
Electrical Current ◽  
Magnetic Shape Memory ◽  
Motion Energy ◽  
Corrugated Beam ◽  
Corrugated Structure

In recent years demand for mobile electrical power has been increased and due to this application, energy harvester systems have been developed to convert mechanical energy into electrical energy using smart materials. In this investigation, a novel arrangement of an energy harvester using Magnetic Shape Memory Alloys (MSMAs) is developed. Elements of MSMA are attached to a corrugated beam and their roots are fixed. The way of harvesting energy from this system is based on conversion of vibration motion energy to the magnetic flux gradient. There is a number of copper coils that wrapped around the MSMA elements in a constant magnetic field. If strain or stress field is applied to the MSMA elements, the electrical current is induced to coils. The problem is studied with analytical methods, and for this purpose, MATLAB solver is used. To simulate the behavior of MSMA substance Kiefer and Lagoudas nonlinear model is used. To verify the results, these two arrangements have been analyzed in ABAQUS. To provide the material properties of MSMA elements, UMAT code has been used. It will be shown that size of this MSMA based energy harvester can become smaller with using corrugated beam structure instead of simple cantilever beam.

Energy Storage and Transportation Based on Sulfuric Acid Decomposition and Synthesis Processes

1987 ◽  
Vol 109 (3) ◽  
pp. 210-214 ◽  
Author(s):  
E. Bilgen
Keyword(s):  
Sulfuric Acid ◽  
Energy Storage ◽  
Thermodynamic Assessment ◽  
Mechanical Energy ◽  
Energy Conversion Efficiency ◽  
Acid Decomposition ◽  
Energy Storage Efficiency ◽  
Sulfuric Acid Decomposition ◽  
Hot Oxygen ◽  
Energy Transportation

A chemical energy storage and transportation system is conceived based on sulfuric acid decomposition and synthesis processes using hot oxygen as a vector. A thermodynamic assessment is carried out to determine the thermal performance of the process; it is found that the energy storage density is about 0.58 GJ/m3 for 365 cycles per year operation, the overall thermal energy storage efficiency is about 62 percent, the energy transportation efficiency is about 29 percent, and the thermal to mechanical energy conversion efficiency is about 25 percent.

Flexoelectric energy harvesters based on Timoshenko laminated beam theory

2017 ◽  
Vol 28 (15) ◽  
pp. 2064-2073 ◽  
Author(s):  
Xu Liang ◽  
Runzhi Zhang ◽  
Shuling Hu ◽  
Shengping Shen
Keyword(s):  
Resonance Frequency ◽  
Energy Conversion ◽  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Mechanical Energy ◽  
Mechanical Vibration ◽  
Beam Theory ◽  
Electrical Energy ◽  
Laminated Beam ◽  
Energy Harvesters

Different from piezoelectricity which is restricted to certain materials, flexoelectricity is a universal electromechanical coupling in all dielectrics. In this work, mechanical energy harvester models were developed based on Timoshenko laminated beam theory, in which the flexoelectric and piezoelectric mechanisms were discussed. For a three-layered energy harvester in parallel configuration, the mechanical vibration energy can be converted into electrical energy due to flexoelectricity, and for the three-layered energy harvester in series configuration, the energy conversion is enhanced by the flexoelectricity. Resonance frequency shifts were observed in the calculations due to flexoelectricity and external circuit resistance. It is found that the electromechanical coupling displayed from the electrical responses versus resonance frequency and resistance. The energy conversion for the three-layered energy harvester system was found to be increased with the decrease in the laminated beam thickness. The energy conversion calculated for different numbers of layers also indicates that laminated energy harvester systems excel single-layered energy harvesters. This work therefore might help in designing flexoelectricity-based energy harvesters.

Rancang Bangun Mekanisme Fess Sebagai Alat Pembanding Pengaruh Geometri Flywheel Terhadap Energi Kinetik Yang Dihasilkan

2019 ◽  
Vol 8 (02) ◽  
pp. 1-6
Author(s):  
Adhe Anggry ◽  
Yuli Dharta ◽  
Andri Wiguna ◽  
Armada Armada ◽  
Ririn Martasari
Keyword(s):  
Free Energy ◽  
Energy Storage ◽  
Kinetic Energy ◽  
Specific Energy ◽  
Mechanical Energy ◽  
Storage System ◽  
Electrical Power ◽  
Electrical Energy ◽  
Energy Storage System ◽  
Tidal Power

Recent days, more and more people are becoming interested in "free-energy". "Free-energy" means the energy sources used freely without to pay. The sources of "free-energy" are sunlight, rainfall, wind energy, wave power, and tidal power. There are other sources of power such as gravity, electrical charge in the atmosphere and ionosphere, and a mass. FESS (Flywheel Energy Storage System) is an attempt to store kinetic energy generated from the rotation flywheel in which the electrical power output from the generator as an input to the motor. Mass flywheel greatly affects the amount of power generated by a generator which will serve as a flywheel device or distributors of energy while at the induction generator to eventually convert mechanical energy into electrical energy and vice versa. In this system design becomes very important for the flywheel can store the kinetic energy. This research aims to design and build mechanisms as a means of comparison FESS flywheel effect of the geometry of the kinetic energy generated. The research method is done by making three different geometric design flywheels, and then analyzed with the help of FESS. From the experimental results, flywheel 1 with a ringtype web-concave generate kinetic energy of 312.30 J and specific energy of 31.23 J / kg, at the flywheel 2 which is type-straight arm kinetic energy gained by 316.73 J and energy specific of 31.67 J / kg and flywheel 3 with a ring-type web-straight kinetic energy obtained by 284.997 J and specific energy of 28.49 J / kg. From the research data we can conclude that each design geometry flywheel has a different contribution to the performance of energy storage.

scholarly journals Methods to Improve Energy Conversion Efficiency of Dielectric Elastomer Generators

2019 ◽  
Vol 804 ◽  
pp. 63-67
Author(s):  
Heng Tong Cheng ◽  
Zhen Qiang Song ◽  
Shijie Zhu ◽  
Kazuhiro Ohyama
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Input Voltage ◽  
Energy Conversion Efficiency ◽  
Stretch Ratio ◽  
Dielectric Elastomer ◽  
Conversion Performance ◽  
Ratio Range

Dielectric elastomer generators (DEGs) are based on the electromechanical response of the dielectric elastomer film sandwiched between the compliant electrodes on each side, which are capable of converting mechanical energy from diverse sources (e.g, ocean wave) into electrical energy. In essence, DEG is a voltage up-converter using mechanical energy to increase the electrical energy of the charge on a soft capacitor. We evaluated the effect of input voltage and the pre-stretch ratios on energy conversion efficiency of DEG. With a power supply of 2.2kV and pre-stretch ratio of 2, the maximum net electrical energy density and energy conversion efficiency in a single harvesting cycle were measured to be 413 J/kg and 15.8%, respectively. The experimental results showed that, with the higher input voltage and the larger stretch ratio range, higher the energy conversion performance of DEG can be achieved.

scholarly journals The Impact of Active and Passive Thermal Management on the Energy Storage Efficiency of Metal Hydride Pairs Based Heat Storage

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3006
Author(s):  
Serge Nyallang Nyamsi ◽  
Ivan Tolj
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Management ◽  
Metal Hydride ◽  
Heat Storage ◽  
Energy Storage Density ◽  
Storage Efficiency ◽  
Transfer Enhancement ◽  
Storage Density ◽  
Energy Storage Efficiency

Two-tank metal hydride pairs have gained tremendous interest in thermal energy storage systems for concentrating solar power plants or industrial waste heat recovery. Generally, the system’s performance depends on selecting and matching the metal hydride pairs and the thermal management adopted. In this study, the 2D mathematical modeling used to investigate the heat storage system’s performance under different thermal management techniques, including active and passive heat transfer techniques, is analyzed and discussed in detail. The change in the energy storage density, the specific power output, and the energy storage efficiency is studied under different heat transfer measures applied to the two tanks. The results showed that there is a trade-off between the energy storage density and the energy storage efficiency. The adoption of active heat transfer enhancement (convective heat transfer enhancement) leads to a high energy storage density of 670 MJ m−3 (close to the maximum theoretical value of 755.3 MJ m−3). In contrast, the energy storage efficiency decreases dramatically due to the increase in the pumping power. On the other hand, passive heat transfer techniques using the bed’s thermal conductivity enhancers provide a balance between the energy storage density (578 MJ m−3) and the energy efficiency (74%). The utilization of phase change material as an internal heat recovery medium leads to a further reduction in the heat storage performance indicators (142 MJ m−3 and 49%). Nevertheless, such a system combining thermochemical and latent heat storage, if properly optimized, can be promising for thermal energy storage applications.

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