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 Study of the influence of material properties in the energy conversion process of thermoelectric generators for waste heat recovery applications

Respuestas ◽  
2020 ◽  
Vol 25 (3) ◽  
Author(s):  
Byron Medina-Delgado ◽  
Guillermo Valencia-Ochoa ◽  
Jorge Duarte-Forero
Keyword(s):  
Heat Flux ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Material Properties ◽  
Waste Heat ◽  
Electrical Power ◽  
Energy Conversion Efficiency ◽  
Conversion Process ◽  
Thermoelectric Generators ◽  
Energy Conversion Process

The present study analyzed the effect of material properties in the energy conversion process of Thermoelectric Generators (TEGs). For the development of the study, two materials whose properties vary with respect to temperature (Bi0.4Sb1.6Te3 and Cu11NiSb4S13) and a material with constant properties (Bi2Te3) were analyzed. Through numerical simulation processes, each material was subjected to different temperature differences to monitor the effect on the electrical output power, heat flux, and energy conversion efficiency. The results showed that neglecting the temperature dependence produces higher or lower performance estimations depending on the temperature levels experienced by the TEG.  Overall, the material Bi2Te3 displayed 35% more electrical power output and conversion efficiency compared to the Bi0.4Sb1.6Te3 material. Therefore, considering the variability of thermoelectric materials demonstrated to be essential to obtain realistic process performance. Also, the heat flux produced by the Fourier effect presents the most significant impact on the electrical power generation of the TEG. Among materials with variable properties, the Bi0.4Sb1.6Te3 increases the conversion efficiency up to 25% compared to the Cu11NiSb4S13. In conclusion, the study of material properties using numerical simulations emerged as a robust and practical tool to evaluate TEG performance.

Performance Improvements in Cooker-Top Gas Burners for Small Aspect Ratio Changes

2017 ◽  
Vol 9 (4) ◽  
Author(s):  
Robson L. Silva ◽  
Bruno V. Sant′Ana ◽  
José R. Patelli ◽  
Marcelo M. Vieira
Keyword(s):  
Energy Conversion ◽  
Fuel Consumption ◽  
Conversion Efficiency ◽  
Minimum Energy ◽  
Energy Conversion Efficiency ◽  
Energy Performance ◽  
Operating Conditions ◽  
Lower Fuel Consumption ◽  
Performance Improvements ◽  
Aspect Ratios

This paper aims to identify performance improvements in cooker-top gas burners for changes in its original geometry, with aspect ratios (ARs) ranging from 0.25 to 0.56 and from 0.28 to 0.64. It operates on liquefied petroleum gas (LPG) and five thermal power (TP) levels. Considering the large number of cooker-top burners currently being used, even slight improvements in thermal performance resulting from a better design and recommended operating condition will lead to a significant reduction of energy consumption and costs. Appropriate instrumentation was used to carry out the measurements and methodology applied was based on regulations from INMETRO (CONPET program for energy conversion efficiency in cook top and kilns), ABNT (Brazilian Technical Standards Normative) and ANP—National Agency of Petroleum, Natural Gas (NG) and Biofuels. The results allow subsidizing recommendations to minimum energy performance standards (MEPS) for residential use, providing also higher energy conversion efficiency and/or lower fuel consumption. Main conclusions are: (i) Smaller aspect ratios result in the same heating capacity and higher efficiency; (ii) higher aspect ratios (original burners) are fuel consuming and inefficient; (iii) operating conditions set on intermediate are lower fuel consumption without significant differences in temperature increases; (iv) Reynolds number lower than 500 provides higher efficiencies.

Thermoelectric Transport in Silicon Germanium Nanocomposite

2008 ◽  
Author(s):  
Hohyun Lee ◽  
Daryoosh Vashaee ◽  
Xiaowei Wang ◽  
Giri Joshi ◽  
Gaohua Zhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Energy Conversion ◽  
Silicon Germanium ◽  
Figure Of Merit ◽  
Waste Heat ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Thermoelectric Effects ◽  
Thermoelectric Transport ◽  
Potential Applications

Direct energy conversion between heat and electrical energy based on thermoelectric effects is attractive for potential applications in waste heat recovery and environmentally-friendly refrigeration. The energy conversion efficiency depends on the dimensionless figure of merit of thermoelectric materials, ZT, which is proportional to the electrical conductivity, the square of the Seebeck coefficient, and the inverse of the thermal conductivity. Currently, the low ZT values of available materials restrict the applications of this technology. However, significant enhancements in ZT were recently reported in nanostructured materials such as superlattices mainly due to their low thermal conductivities. According to recent studies, the reduced thermal conductivity of nanostructures is attributed to the large number of interfaces at which phonons are scattered. Based on this idea, nanocomposites are expected to have a lower thermal conductivity than their bulk counterparts with low fabrication cost just by mixing nano sized particles. In this work, we will discuss mechanisms of thermoelectric transport via modeling and provide experimental evidence on the enhancement of thermoelectric figure of merit in SiGe-based nanocomposites.

scholarly journals Design of a Load Torque Based Control Strategy for Improving Electric Tractor Motor Energy Conversion Efficiency

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Mengnan Liu ◽  
Liyou Xu ◽  
Zhili Zhou
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Control Strategy ◽  
Electric Motor ◽  
Mechanical Performance ◽  
Electrical Power ◽  
Energy Conversion Efficiency ◽  
Load Torque ◽  
Novel Method ◽  
The Common

In order to improve the electrical conversion efficiency of an electric tractor motor, a load torque based control strategy (LTCS) is designed in this paper by using a particle swarm optimization algorithm (PSO). By mathematically modeling electric-mechanical performance and theoretical energy waste of the electric motor, as well as the transmission characteristics of the drivetrain, the objective function, control relationship, and analytical platform are established. Torque and rotation speed of the motor’s output shaft are defined as manipulated variables. LTCS searches the working points corresponding to the best energy conversion efficiency via PSO to control the running status of the electric motor and uses logic and fuzzy rules to fit the search initialization for load torque fluctuation. After using different plowing forces to imitate all the common tillage forces, the simulation of traction experiment is conducted, which proves that LTCS can make the tractor use electrical power efficiently and maintain agricultural applicability on farmland conditions. It provides a novel method of fabricating a more efficient electric motor used in the traction of an off-road vehicle.

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.

Strategies for extending charge separation in colloidal nanostructured quantum dot materials

2019 ◽  
Vol 21 (42) ◽  
pp. 23283-23300 ◽  
Author(s):  
Partha Maity ◽  
Hirendra N. Ghosh
Keyword(s):  
Solar Cell ◽  
Quantum Dot ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Charge Separation ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Colloidal Nanocrystals

Different processes are involved in a quantum dot sensitized solar cell (QDSC). This article reviews the probable ways to extend charge separation in colloidal nanocrystals for the elevation of solar to electrical energy conversion efficiency in QDSCs.

scholarly journals Performance Examination and Design Optimization of Thermoelectric Sensor Configuration for Energy Harvesting From Air Conditioner Waste Heat

2019 ◽  
Vol 8 (3S2) ◽  
pp. 231-237
Keyword(s):  
Conversion Efficiency ◽  
Waste Heat ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Air Conditioner ◽  
Proper Design ◽  
Thermoelectric Sensor ◽  
Working Principle ◽  
Sensor Configuration ◽  
Performance Examination

Due to energy crisis as well as environmental pollution issues, it is necessity for the establishment of alternatives energy harvester system in reducing the dependency of the primary resources such as oil and coal. The purpose of this research is to investigate working principle of the thermoelectric (TE) which able to harvest waste heat energy through a portable air conditioner and convert it to electrical energy. To optimise the TE performance, a number of TE configurations via experimental analysis are carried out which are significantly affecting the output power and the conversion efficiency of the TE system. From this research, it is concluded that proper design of the TE system is required to improve its energy conversion efficiency.

scholarly journals Studies on surface modification of polypropylene composite bipolar plates using an electroless deposition technique

RSC Advances ◽  
2020 ◽  
Vol 10 (41) ◽  
pp. 24330-24342
Author(s):  
Rungsima Yeetsorn ◽  
Walaiporn Prissanaroon Ouajai ◽  
Kannika Onyu
Keyword(s):  
Surface Modification ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Electroless Deposition ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Combustion Engines ◽  
Bipolar Plates ◽  
Deposition Technique ◽  
Polypropylene Composite

The DMFC is predominantly noticeable because it can convert chemical energy directly into electrical energy with higher energy conversion efficiency (∼65%) compared to the efficiency of traditional combustion engines (40%) and with lower emissions.

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