Modulated Magneto-Thermal Response of La0.85Sr0.15MnO3 and (Ni0.6Cu0.2Zn0.2)Fe2O4 Composites for Thermal Energy Harvesters

2019 ◽  
Vol 4 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Hyun-Cheol Song ◽  
Deepam Maurya ◽  
Jinsung Chun ◽  
Yuan Zhou ◽  
Myung-Eun Song ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Energy Conversion ◽  
Thermal Energy ◽  
Mechanical Energy ◽  
Thermal Response ◽  
Electrical Energy ◽  
Soft Magnetic ◽  
Efficient Operation ◽  
Energy Harvesters ◽  
Operational Frequency

Abstract The magneto-thermoelectric generator (MTG) converts wasted thermal energy into electrical energy in two steps. The first step involves thermal to mechanical energy conversion through balance of magnetic and elastic forces and the second step involves mechanical to electrical energy conversion through piezoelectric effect. The requirements for soft magnetic material in improving the efficiency of first step were identified and met through the design of a composite architecture. The Curie temperature of La(1–x)SrxMnO3 can be engineered to be near room temperature by modifying the Sr content. Composite of La0.85Sr0.15MnO3 (LSMO) and Ni0.6Cu0.2Zn0.2Fe2O4 (NCZF) was found to exhibit high saturation (Ms) and remnant (Mr) magnetization magnitude while maintaining the soft magnetic nature. Two-step sintering was found to prevent the inter-diffusion of LSMO and NCZF phases and provided high density without grain growth. The LSMO-NCZF (70:30 wt%) composite exhibited a large variation in Ms with respect to the change in temperature near Curie temperature which meets the requirements for efficient operation of MTG. The fabricated MTG using LSMO-NCZF (70:30 wt%) composite reached 0.2 Hz operational frequency and generated electrical output voltage of 2 Vp–p and peak power of 17 µW under the thermal gradient of 80 °C (0 °C/80 °C).

scholarly journals Pyroelectric Energy Conversion and Its Applications—Flexible Energy Harvesters and Sensors

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2170 ◽  
Author(s):  
Atul Thakre ◽  
Ajeet Kumar ◽  
Hyun-Cheol Song ◽  
Dae-Yong Jeong ◽  
Jungho Ryu
Keyword(s):  
Energy Harvesting ◽  
Energy Conversion ◽  
Thermal Energy ◽  
Cost Effective ◽  
Electrical Energy ◽  
Energy Scavenging ◽  
Hybrid Energy ◽  
Energy Harvesters ◽  
Sensor Applications ◽  
Sensing Applications

Among the various forms of natural energies, heat is the most prevalent and least harvested energy. Scavenging and detecting stray thermal energy for conversion into electrical energy can provide a cost-effective and reliable energy source for modern electrical appliances and sensor applications. Along with this, flexible devices have attracted considerable attention in scientific and industrial communities as wearable and implantable harvesters in addition to traditional thermal sensor applications. This review mainly discusses thermal energy conversion through pyroelectric phenomena in various lead-free as well as lead-based ceramics and polymers for flexible pyroelectric energy harvesting and sensor applications. The corresponding thermodynamic heat cycles and figures of merit of the pyroelectric materials for energy harvesting and heat sensing applications are also briefly discussed. Moreover, this study provides guidance on designing pyroelectric materials for flexible pyroelectric and hybrid energy harvesting.

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.

Stress Analysis of Smart Beam Energy Harvesters

2016 ◽  
Author(s):  
Nathan S. Hosking ◽  
Zahra Sotoudeh
Keyword(s):  
Smart Materials ◽  
Mechanical Energy ◽  
Strain Analysis ◽  
Electrical Energy ◽  
Structural Dynamic ◽  
Energy Harvesters ◽  
Beam Equations ◽  
Variational Asymptotic ◽  
Strain Components ◽  
Smart Beam

In this paper, we study fully coupled electromagnetic-elastic behaviors present in the structures of smart beams using variational asymptotic beam sections and geometrically exact fully intrinsic beam equations combined in a consistent theory. We present results for smart beams under various oscillatory loads in both the axial and transverse directions and calculate the corresponding deformations. Recovery equations are employed to construct the full 3D stress and strain components in order to complete a full stress / strain analysis. Smart materials change mechanical energy to electrical energy; therefore, changing the structural dynamic behavior of the structure and its stiffness matrix.

Investigation of Vibration Energy Harvesting Using Two Cantilevers With Random Input

2017 ◽  
Author(s):  
Wei Yang ◽  
Panagiotis Alevras ◽  
Shahrzad Towfighian
Keyword(s):  
Mechanical Energy ◽  
Duffing Oscillator ◽  
Electrical Energy ◽  
Potential Energy Function ◽  
Excitation Level ◽  
Vibration Energy ◽  
Random Input ◽  
Vibration Energy Harvesting ◽  
Energy Harvesters ◽  
Low Performance

There is a growing interest to convert ambient mechanical energy to electrical energy by vibration energy harvesters. Realistic vibrations are random and spread over a large frequency range. Most energy harvesters are linear with narrow frequency bandwidth and show low performance, which led to creation of nonlinear harvesters that have larger bandwidth. This article presents a simulation study of a nonlinear energy harvester that contains two cantilever beams coupled by magnetic force. One of the cantilever beam is covered partially by piezoelectric material, while the other beam is normal to the first one and is used to create a variable potential energy function. The variable double-well potential function enables optimum conversion of the kinetic energy and thus larger output. The system is modeled by coupled Duffing oscillator equations. To represent the ambient vibrations, the response to Gaussian random input signal (generated by Shinozuka formula) is studied using power spectral density. The effects of different parameters on the system are also investigated. The results show that the double cantilever harvester has a threshold distance, where the harvester can perform optimally regardless of the excitation level. This observation is opposite to that of the conventional fixed magnet cantilever system where the optimal distance varies with the excitation level. Results of this study can be used to enhance energy efficiency of vibration energy harvesters.

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 A human body as an energy source

2021 ◽  
pp. 60-65
Author(s):  
Yevgen Honcharov ◽  
Nataliya Kriukova ◽  
Vladislav Markov ◽  
Igor Polyakov
Keyword(s):  
Thermal Energy ◽  
Human Body ◽  
Power Plants ◽  
Experimental Testing ◽  
Mechanical Energy ◽  
Living Organism ◽  
Electrical Energy ◽  
The Body ◽  
Charge Carriers ◽  
The Brain

The article deals with the actual problems of using the energy released by the human body. The question arises how much energy can the human body generate? Is it possible to use this energy for domestic and industrial needs? In the 18th and 19th centuries, the first scientific works on this topic appeared. It turned out that the charge carriers in the proteins of a living organism are protons and electrons, which, together with the electron-hole conduction system, create a single conductivity inherent only in a living organism. The electrical activity of the brain is assessed by voltage pulses with an amplitude of 500 μV of various frequencies from 0.5 to 55 Hz. It is impossible to receive pulses with such a frequency and such an amplitude from only ionic-type charge carriers. Electrochemical current sources are inertial; therefore, this fact can be direct evidence of the presence of electronic movement of charge carriers in the brain and the nervous system as a whole. It is quite realistic to use the thermal energy of the human body. Currently, the central building of the Stockholm railway station has been turned into a kind of experimental testing ground. Every day about 250 thousand people pass through the station building, who emit up to 25 MW of thermal energy. Most of it in the form of heated air is collected in ventilation and through heat exchangers energy is transferred to heat water in the heating system of another building. According to rough estimates, the efficiency of such a system can save up to 25% of the energy spent on heating the building. Inside a person, electric currents of various frequencies are generated in 7 biological power plants: in the heart, in the brain and in the five sense organs. All the electricity that is generated inside the human body is absorbed by its own tissues. Not a single electron produced inside a living organism leaves the human body, and does not pass into the environment, but is absorbed by the skin. This is the reason for the closure of the human electrical system. The body itself absorbs all the electricity that it previously produced. The energy generated by the human body is divided into mechanical, thermal, and electrical. The thermal energy of the human body can be used most effectively. Mechanical energy can also be used, but with much less efficiency. The electrical energy of the human body at this stage in the development of science and technology is practically impossible to use. Its use is likely to become real in the very distant future

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.

scholarly journals Development of Smart Shoes Using Piezoelectric Material

2021 ◽  
Vol 7 (1) ◽  
pp. 49-55
Author(s):  
Affa Rozana Abdul Rashid ◽  
Nur Insyierah Md Sarif ◽  
Khadijah Ismail
Keyword(s):  
Piezoelectric Material ◽  
Alternative Energy ◽  
Piezoelectric Materials ◽  
Mechanical Energy ◽  
Electronic Devices ◽  
Electrical Energy ◽  
Small Scale ◽  
Power Electronic ◽  
Energy Harvesters ◽  
Almost All

The consumption of low-power electronic devices has increased rapidly, where almost all applications use power electronic devices. Due to the increase in portable electronic devices’ energy consumption, the piezoelectric material is proposed as one of the alternatives of the significant alternative energy harvesters. This study aims to create a prototype of “Smart Shoes” that can generate electricity using three different designs embedded by piezoelectric materials: ceramic, polymer, and a combination of both piezoelectric materials. The basic principle for smart shoes’ prototype is based on the pressure produced from piezoelectric material converted from mechanical energy into electrical energy. The piezoelectric material was placed into the shoes’ sole, and the energy produced due to the pressure from walking, jogging, and jumping was measured. The energy generated was stored in a capacitor as piezoelectric material produced a small scale of energy harvesting. The highest energy generated was produced by ceramic piezoelectric material under jumping activity, which was 1.804 mJ. Polymer piezoelectric material produced very minimal energy, which was 55.618 mJ. The combination of both piezoelectric materials produced energy, which was 1.805 mJ from jumping activity.

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.

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