scholarly journals 3D extruded composite thermoelectric threads for flexible energy harvesting

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
J. Peng ◽  
I. Witting ◽  
N. Geisendorfer ◽  
M. Wang ◽  
M. Chang ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Low Power ◽  
Percolation Theory ◽  
Volume Fraction ◽  
Void Volume Fraction ◽  
Thermal Gradients ◽  
Lateral Compression ◽  
Partial Alignment ◽  
Flexible Thermoelectric ◽  
Pressure Controlled

AbstractWhereas the rigid nature of standard thermoelectrics limits their use, flexible thermoelectric platforms can find much broader applications, for example, in low-power, wearable energy harvesting for internet-of-things applications. Here we realize continuous, flexible thermoelectric threads via a rapid extrusion of 3D-printable composite inks (Bi2Te3n- or p-type micrograins within a non-conducting polymer as a binder) followed by compression through a roller-pair, and we demonstrate their applications in flexible, low-power energy harvesting. The thermoelectric power factors of these threads are enhanced up to 7 orders-of-magnitude after lateral compression, principally due to improved conductivity resulting from reduced void volume fraction and partial alignment of thermoelectric micrograins. This dependence is quantified using a conductivity/Seebeck vise for pressure-controlled studies. The resulting grain-to-grain conductivity is well explained with a modified percolation theory to model a pressure-dependent conductivity. Flexible thermoelectric modules are demonstrated to utilize thermal gradients either parallel or transverse to the thread direction.

Environment and Application Testbed for Low-Power Energy Harvesting System Design

2020 ◽  
pp. 1-1
Author(s):  
Lukas Sigrist ◽  
Andres Gomez ◽  
Matthias Leubin ◽  
Jan Beutel ◽  
Lothar Thiele
Keyword(s):  
Energy Harvesting ◽  
Low Power ◽  
System Design ◽  
Energy Harvesting System

scholarly journals A Self-Powered PMFC-Based Wireless Sensor Node for Smart City Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Daniel Ayala-Ruiz ◽  
Alejandro Castillo Atoche ◽  
Erica Ruiz-Ibarra ◽  
Edith Osorio de la Rosa ◽  
Javier Vázquez Castillo
Keyword(s):  
Energy Harvesting ◽  
Low Power ◽  
Sensor Node ◽  
Smart Cities ◽  
Cloud Services ◽  
Environmental Data ◽  
Security And Privacy ◽  
Wireless Sensor ◽  
Ultra Low Power ◽  
Self Powered

Long power wide area networks (LPWAN) systems play an important role in monitoring environmental conditions for smart cities applications. With the development of Internet of Things (IoT), wireless sensor networks (WSN), and energy harvesting devices, ultra-low power sensor nodes (SNs) are able to collect and monitor the information for environmental protection, urban planning, and risk prevention. This paper presents a WSN of self-powered IoT SNs energetically autonomous using Plant Microbial Fuel Cells (PMFCs). An energy harvesting device has been adapted with the PMFC to enable a batteryless operation of the SN providing power supply to the sensor network. The low-power communication feature of the SN network is used to monitor the environmental data with a dynamic power management strategy successfully designed for the PMFC-based LoRa sensor node. Environmental data of ozone (O3) and carbon dioxide (CO2) are monitored in real time through a web application providing IoT cloud services with security and privacy protocols.

scholarly journals Topology optimized thermoelectric generator: a parametric study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
John Mativo ◽  
Kevin Hallinan ◽  
Uduak George ◽  
Greg Reich ◽  
Robin Steininger
Keyword(s):  
Topology Optimization ◽  
Thermoelectric Generator ◽  
Volume Fraction ◽  
Power Conversion ◽  
Power Production ◽  
Power Reduction ◽  
Void Volume Fraction ◽  
Thermoelectric Generators ◽  
Maximal Power ◽  
Design Yield

Abstract Typical thermoelectric generator legs are brittle which limits their application in vibratory and shear environments. Research is conducted to develop compliant thermoelectric generators (TEGs) capable of converting thermal loads to power, while also supporting shear and vibratory loads. Mathematical structural, thermal, and power conversion models are developed. Topology optimization is employed to tailor the TEG design yield maximal power production while sustaining the applied shear and vibratory loads. As a specific example, results are presented for optimized TEG legs with a void volume fraction of 0.2 that achieve compliance shear displacement of 0.0636 (from a range of 0.0504 to 0.6079). In order to achieve the necessary compliance to support the load, the power reduction is reduced by 20% relative to similarly sized void free TEG legs.

scholarly journals Forming Limit Stress Diagram Prediction of Pure Titanium Sheet Based on GTN Model

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1783 ◽  
Author(s):  
Tao Huang ◽  
Mei Zhan ◽  
Kun Wang ◽  
Fuxiao Chen ◽  
Junqing Guo ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Pure Titanium ◽  
Void Volume Fraction ◽  
Void Volume ◽  
Forming Limit ◽  
Stress And Strain ◽  
Gtn Model ◽  
Stress Diagram ◽  
Limit Stress ◽  
Hemispherical Punch

In this paper, the initial values of damage parameters in the Gurson–Tvergaard–Needleman (GTN) model are determined by a microscopic test combined with empirical formulas, and the final accurate values are determined by finite element reverse calibration. The original void volume fraction (f0), the volume fraction of potential nucleated voids (fN), the critical void volume fraction (fc), the void volume fraction at the final failure (fF) of material are assigned as 0.006, 0.001, 0.03, 0.06 according to the simulation results, respectively. The hemispherical punch stretching test of commercially pure titanium (TA1) sheet is simulated by a plastic constitutive formula derived from the GTN model. The stress and strain are obtained at the last loading step before crack. The forming limit diagram (FLD) and the forming limit stress diagram (FLSD) of the TA1 sheet under plastic forming conditions are plotted, which are in good agreement with the FLD obtained by the hemispherical punch stretching test and the FLSD obtained by the conversion between stress and strain during the sheet forming process. The results show that the GTN model determined by the finite element reverse calibration method can be used to predict the forming limit of the TA1 sheet metal.

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