scholarly journals Investigation of novel thermoelectric sensor array configurations operating under non‐uniform temperature distribution conditions for the measurement of maximum output power in an energy harvesting system

Author(s):  
Rakesh Thankakan ◽  
Edward Rajan Samuel Nadar
2015 ◽  
Vol 25 (01) ◽  
pp. 1640007 ◽  
Author(s):  
Chia-Lun Chang ◽  
Tai-Cheng Lee

A compact multi-input thermoelectric energy harvesting system implemented in a 0.18[Formula: see text][Formula: see text]m CMOS technology is proposed to extract electrical energy from human body heat. By combining the techniques on inductor sharing and bidirectional power converter, the harvesting- and regulating-stage circuits in conventional energy harvesting system can be merged into a single-stage circuit. With the proposed duty-cycle-based strategy for maximum power extraction and the high-efficiency timing scheme for inductor sharing, the proposed multi-input thermoelectric energy harvesting system can ensure optimal power transfer from each thermoelectric energy source without sacrificing power conversion efficiency (PCE) and maximum output power capability. The peak PCE is achieved at 58.5%, the maximum end-to-end output power is 2.43[Formula: see text]mW, and the maximum output power capability is 32.4[Formula: see text]mW while the storage capacitor is fully charged.


2014 ◽  
Vol 976 ◽  
pp. 159-163 ◽  
Author(s):  
Roberto Ambrosio ◽  
Hector Gonzalez ◽  
Mario Moreno ◽  
Alfonso Torres ◽  
Rafael Martinez ◽  
...  

In this work is presented a study of a piezoelectric energy harvesting device used for low power consumption applications operating at relative low frequency. The structure consists of a cantilever beam made by Lead Zirconate Titanate (PZT) layer with two gold electrodes for electrical contacts. The piezoelectric material was selected taking into account its high coupling coefficients. Different structures were analyzed with variations in its dimensions and shape of the cantilever. The devices were designed to operate at the resonance frequency to get maximum electrical power output. The structures were simulated using finite element (FE) software. The analysis of the harvesting devices was performed in order to investigate the influence of the geometric parameters on the output power and the natural frequency. To validate the simulation results, an experiment with a PZT cantilever with brass substrate was carried out. The experimental data was found to be very close to simulation data. The results indicate that large structures, in the order of millimeters, are the ideal for piezoelectric energy harvesting devices providing a maximum output power in the range of mW


Author(s):  
Yu-ji Gao ◽  
Yong-gang Leng ◽  
Lin-chen Shen ◽  
Yan Guo

A vibration energy harvester is typically composed of a spring–mass system, with the advantage of high energy density, simple structure and easily being miniaturized. Recently, effects of cantilever beam’s structural parameters and cross-section shape on energy-harvesting micro-device is concerned and investigated in this paper, so as to study its performance of energy harvesting to meet the needs of low resonant frequency and maximum output power. The effect of a cantilever beam’s structure dimensions as well as quality of the mass on the device’s resonance frequency and maximum output power can be detected through formula computing. Further study on effect of a cantilever beam’s cross-section shape has also been worked out. According to the simulation experimental results gained from ANSYS with appropriate parameters defined by theoretical derivation, we manage to receive concordant conclusions. To receive a better performance of the energy harvester, we should choose a shorter, wider and thicker cantilever beam with rectangular cross-section and heavier mass at its end. However, to meet the requirement of low resonant frequency for piezoelectric vibration energy harvesting, we still need to define either an upper or a lower limit while choosing parameters of the device.


Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 872
Author(s):  
Rujun Song ◽  
Chengwei Hou ◽  
Chongqiu Yang ◽  
Xianhai Yang ◽  
Qianjian Guo ◽  
...  

This paper studies a novel enhanced energy-harvesting method to harvest water flow-induced vibration with a tandem arrangement of two piezoelectric energy harvesters (PEHs) in the direction of flowing water, through simulation modeling and experimental validation. A mathematical model is established by two individual-equivalent single-degree-of-freedom models, coupled with the hydrodynamic force obtained by computational fluid dynamics. Through the simulation analysis, the variation rules of vibration frequency, vibration amplitude, power generation and the distribution of flow field are obtained. And experimental tests are performed to verify the numerical calculation. The experimental and simulation results show that the upstream piezoelectric energy harvester (UPEH) is excited by the vortex-induced vibration, and the maximum value of performance is achieved when the UPEH and the vibration are resonant. As the vortex falls off from the UPEH, the downstream piezoelectric energy harvester (DPEH) generates a responsive beat frequency vibration. Energy-harvesting performance of the DPEH is better than that of the UPEH, especially at high speed flows. The maximum output power of the DPEH (371.7 μW) is 2.56 times of that of the UPEH (145.4 μW), at a specific spacing between the UPEN and the DPEH. Thereupon, the total output power of the two tandem piezoelectric energy harvester systems is significantly greater than that of the common single PEH, which provides a good foreground for further exploration of multiple piezoelectric energy harvesters system.


Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 508
Author(s):  
Kui You ◽  
Zihan Zhou ◽  
Chao Gao ◽  
Qiao Yang

Biochar is a kind of carbon-rich material formed by pyrolysis of biomass at high temperature in the absence or limitation of oxygen. It has abundant pore structure and a large surface area, which could be considered the beneficial characteristics for electrodes of microbial electrochemical systems. In this study, reed was used as the raw material of biochar and six biochar-based electrode materials were obtained by three methods, including one-step biochar cathodes (BC 800 and BC 700), biochar/polyethylene composite cathodes (BP 5:5 and BP 6:4), and biochar/polyaniline/hot-melt adhesive composite cathode (BPP 5:1:4 and BPP 4:1:5). The basic physical properties and electrochemical properties of the self-made biochar electrode materials were characterized. Selected biochar-based electrode materials were used as the cathode of sediment microbial electrochemical reactors. The reactor with pure biochar electrode (BC 800) achieves a maximum output power density of 9.15 ± 0.02 mW/m2, which increases the output power by nearly 80% compared with carbon felt. When using a biochar/polyaniline/hot-melt adhesive (BPP 5:1:4) composite cathode, the output power was increased by 2.33 times. Under the premise of ensuring the molding of the material, the higher the content of biochar, the better the electrochemical performance of the electrodes. The treatment of reed powder before pyrolysis is an important factor for the molding of biochar. The one-step molding biochar cathode had satisfactory performance in sediment microbial electrochemical systems. By exploring the biochar-based electrode, waste biomass could be reused, which is beneficial for the environment.


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