Topology Optimization of Multimaterial Thermoelectric Structures

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Xiaoqiang Xu ◽  
Yongjia Wu ◽  
Lei Zuo ◽  
Shikui Chen
Keyword(s):  
Topology Optimization ◽  
Thermoelectric Materials ◽  
Power Plants ◽  
High Efficiency ◽  
Waste Heat ◽  
Oil Refining ◽  
Numerical Verification ◽  
Temperature Range ◽  
Multiple Materials ◽  
P Type

Abstract A large amount of energy from power plants, vehicles, oil refining, and steel or glass making process is released to the atmosphere as waste heat. The thermoelectric generator (TEG) provides a way to reutilize this portion of energy by converting temperature differences into electricity using Seebeck phenomenon. Because the figures of merit zT of the thermoelectric materials are temperature-dependent, it is not feasible to achieve high efficiency of the thermoelectric conversion using only one single thermoelectric material in a wide temperature range. To address this challenge, the authors propose a method based on topology optimization to optimize the layouts of functional graded TEGs consisting of multiple materials. The multimaterial TEG is optimized using the solid isotropic material with penalization (SIMP) method. Instead of dummy materials, both the P-type and N-type electric conductors are optimally distributed with two different practical thermoelectric materials. Specifically, Bi2Te3 and Zn4Sb3 are selected for the P-type element while Bi2Te3 and CoSb3 are employed for the N-type element. Two optimization scenarios with relatively regular domains are first considered with one optimizing on both the P-type and N-type elements simultaneously, and the other one only on single P-type element. The maximum conversion efficiency could reach 9.61% and 12.34% respectively in the temperature range from 25 °C to 400 °C. CAD models are reconstructed based on the optimization results for numerical verification. A good agreement between the performance of the CAD model and optimization result is achieved, which demonstrates the effectiveness of the proposed method.

Multimaterial Topology Optimization of Thermoelectric Generators

2019 ◽  
Author(s):  
Xiaoqiang Xu ◽  
Yongjia Wu ◽  
Lei Zuo ◽  
Shikui Chen
Keyword(s):  
Topology Optimization ◽  
Conversion Efficiency ◽  
Thermoelectric Materials ◽  
Power Plants ◽  
High Efficiency ◽  
Waste Heat ◽  
Computational Simulation ◽  
Oil Refining ◽  
Temperature Range ◽  
Multiple Materials

Abstract Over 50% of the energy from power plants, vehicles, oil refining, and steel or glass making process is released to the atmosphere as waste heat. As an attempt to deal with the growing energy crisis, the solid-state thermoelectric generator (TEG), which converts the waste heat into electricity using Seebeck phenomenon, has gained increasing popularity. Since the figures of merit of the thermoelectric materials are temperature dependent, it is not feasible to achieve high efficiency of the thermoelectric conversion using only one single thermoelectric material in a wide temperature range. To address this challenge, this paper proposes a method based on topology optimization to optimize the layouts of functional graded TEGs consisting of multiple materials. The objective of the optimization problem is to maximize the output power and conversion efficiency as well. The proposed method is implemented using the Solid Isotropic Material with Penalization (SIMP) method. The proposed method can make the most of the potential of different thermoelectric materials by distributing each material into its optimal working temperature interval. Instead of dummy materials, both the P and N-type electric conductors are optimally distributed with two different practical thermoelectric materials, namely Bi2Te3 & PbTe for P-type, and Bi2Te3 & CoSb3 for N-type respectively, with the yielding conversion efficiency around 12.5% in the temperature range Tc = 25°C and Th = 400°C. In the 2.5D computational simulation, however, the conversion efficiency shows a significant drop. This could be attributed to the mismatch of the external load and internal TEG resistance as well as the grey region from the topology optimization results as discussed in this paper.

Structure Design for High Performance n-Type Polymer Thermoelectric Materials

2021 ◽  
Author(s):  
Qi Zhang ◽  
Hengda Sun ◽  
Meifang Zhu
Keyword(s):  
Conjugated Polymers ◽  
Thermoelectric Materials ◽  
High Performance ◽  
Waste Heat ◽  
Building Blocks ◽  
Structure Design ◽  
Potential Candidate ◽  
Polymer Backbone ◽  
P Type ◽  
Polymer Thermoelectric

Abstract Organic thermoelectric (OTE) materials have been regarded as a potential candidate to harvest waste heat from complex, low temperature surfaces of objects and convert it into electricity. Recently, n-type conjugated polymers as organic thermoelectric materials have aroused intensive research in order to improve their performance to match up with their p-type counterpart. In this review, we discuss aspects that affect the performance of n-type OTEs, and further focus on the effect of planarity of backbone on doping efficiency and eventually the TE performance. We then summarize strategies such as implementing rigid n-type polymer backbone or modifying conventional polymer building blocks for more planar conformation. In the outlook part, we conclude forementioned devotions and point out new possibility that may promote the future development of this field.

Making Thermoelectric Materials SnxGa1−xNx Alloys by Magnetron Sputtering Technology

2015 ◽  
Vol 1120-1121 ◽  
pp. 490-492
Author(s):  
Xing Long Guo
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Magnetron Sputtering ◽  
Thermoelectric Materials ◽  
Power Plants ◽  
Waste Heat ◽  
Heat Pumps ◽  
High Mechanical Strength ◽  
Power Generators ◽  
Device Operation

Thermoelectric materials are of interest for applications as heat pumps and power generators. Thermoelectric properties of SnxGa1−xN alloys have been investigated. It was found that as Sn concentration increases, the thermal conductivity decreases and power factor increases, which leads to an increase in the TE figure of ZT. The valuge of ZT was found to be 0.07 at 300 K for Sn0.38Ga0.64N alloy. The results indicate that SnGaN alloys could be potentially important TE materials for many applications, especially for prolonged TE device operation at high temperatures, such as for recovery of waste heat from automobile, aircrafts, and power plants due to their superior physical properties, including the ability of operating at high temperature/high power conditions, high mechanical strength and stability, and radiation hardness.

Ternary Copper-Based Diamond-Like Semiconductors for Thermoelectric Applications

2009 ◽  
Vol 1166 ◽  
Author(s):  
Donald T Morelli ◽  
Eric J. Skoug
Keyword(s):  
Thermoelectric Materials ◽  
Waste Heat Recovery ◽  
High Efficiency ◽  
Waste Heat ◽  
Low Cost ◽  
Electrical Energy ◽  
Clean Energy ◽  
Direct Conversion ◽  
Thermoelectric Device ◽  
Climate Control

AbstractThermoelectric materials can provide sources of clean energy and increase the efficiency of existing processes. Solar energy, waste heat recovery, and climate control are examples of applications that could benefit from the direct conversion between thermal and electrical energy provided by a thermoelectric device. The widespread use of thermoelectric devices has been prevented by their lack of efficiency, and thus the search for high-efficiency thermoelectric materials is ongoing. Here we describe our initial efforts studying copper-containing ternary compounds for use as high-efficiency thermoelectric materials that could provide low-cost alternatives to their silver-containing counterparts. The compounds of interest are semiconductors that crystallize in structures that are variants of binary zincblende structure compounds. Two examples are the compounds Cu2SnSe3 and Cu3SbSe4, for which we present here preliminary thermoelectric characterization data.

scholarly journals Combined Cycles Permit the Most Environmentally Benign Conversion of Fossil Fuels to Electricity

1990 ◽  
Author(s):  
Guenther Haupt ◽  
John S. Joyce ◽  
Konrad Kuenstle
Keyword(s):  
Environmental Impact ◽  
Power Plants ◽  
Fossil Fuels ◽  
Coal Gasification ◽  
High Efficiency ◽  
Waste Heat ◽  
Primary Energy ◽  
Combined Cycle ◽  
Point Of View ◽  
Steam Boiler

The environmental impact of unfired combined-cycle blocks of the GUD® type is compared with that of equivalent reheat steam boiler/turbine units. The outstandingly high efficiency of GUD blocks not only conserves primary-energy resources, but also commensurately reduces undesirable emissions and unavoidable heat rejection to the surroundings. In addition to conventional gas or oil-fired GUD blocks, integrated coal-gasification combined-cycle (ICG-GUD) blocks are investigated from an ecological point of view so as to cover the whole range of available fossil fuels. For each fuel and corresponding type of GUD power plant the most appropriate conventional steam-generating unit of most modern design is selected for comparison purposes. In each case the relative environmental impact is stated in the form of quantified emissions, effluents and waste heat, as well as of useful byproducts and disposable solid wastes. GUD blocks possess the advantage that they allow primary measures to be taken to minimize the production of NOx and SOx, whereas both have to be removed from the flue gases of conventional steam stations by less effective and desirable, albeit more expensive secondary techniques, e.g. flue-gas desulfurization and DENOX systems. In particular, the comparison of CO2 release reveals a significantly lower contribution by GUD blocks to the greenhouse effect than by other fossil-fired power plants.

SOFC Management in Distributed Energy Systems

2011 ◽  
Vol 8 (3) ◽  
Author(s):  
Daniele Chiappini ◽  
Andrea Luigi Facci ◽  
Laura Tribioli ◽  
Stefano Ubertini
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Waste Heat ◽  
Energy Systems ◽  
Hot Water ◽  
Pollutant Emissions ◽  
Heating Process ◽  
Distributed Energy ◽  
Utilization Factor ◽  
Distributed Power Generation

Among the distributed generation emerging technologies, solid oxide fuel cells (SOFCs) seem to be the most promising for small and medium power (up to 1 MW) as they feature extremely high efficiency and low pollutant emissions, and the high-grade waste heat can be utilized for space heating, process steam, and/or domestic hot water demands. As their main drawbacks are high cost and relatively short lifetime, much research is devoted to solve technological problems and to develop less expensive materials and mass production processes. However, even if SOFCs are close to commercialization and several demonstration units are already running, only few researches have been performed on their integration in power plants for distributed power generation, which are complex systems made up of different components that have to satisfy energy requirements (heat, electricity, and cooling). In this paper, we investigate the behavior of SOFCs in distributed energy systems and how their operation in terms of load and fuel utilization factor could optimize fuel consumption and/or minimize energy costs. The potential advantages of SOFCs related to their excellent part-load operation and their ability to meet and follow the highly noncoincident electric and thermal loads in either grid-connected or stand-alone configurations are discussed.

scholarly journals Computationally Modelling the Use of Nanotechnology to Enhance the Performance of Thermoelectric Materials

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5096
Author(s):  
Peter Spriggs ◽  
Qing Wang
Keyword(s):  
High Temperature ◽  
Thermoelectric Materials ◽  
Phonon Scattering ◽  
Waste Heat ◽  
Global Climate ◽  
Computational Simulation ◽  
Electrical Energy ◽  
Maximum Efficiency ◽  
Temperature Range ◽  
Band Engineering

The increased focus on global climate change has meant that the thermoelectric market has received considerably more attention. There are many processes producing large amounts of waste heat that can be utilised to generate electrical energy. Thermoelectric devices have long suffered with low efficiencies, but this can be addressed in principle by improving the performance of the thermoelectric materials these devices are manufactured with. This paper investigates the thermoelectric performance of market standard thermoelectric materials before analysing how this performance can be improved through the adoption of various nanotechnology techniques. This analysis is carried out through the computational simulation of the materials over low-, mid- and high-temperature ranges. In the low-temperature range, through the use of nanopores and full frequency phonon scattering, Mg0.97Zn0.03Ag0.9Sb0.95 performed best with a ZT value of 1.45 at 433 K. Across the mid-temperature range a potentially industry leading ZT value of 2.08 was reached by AgSbTe1.85Se0.15. This was carried out by simulating the effect of band engineering and the introduction of dense stacking faults due to the addition of Se into AgSbTe2. AgSbTe1.85Se0.15 cannot be implemented in devices operating above 673 K because it degrades too quickly. Therefore, for the top 200 K of the mid-temperature range a PbBi0.002Te–15% Ag2Te nanocomposite performed best with a maximum ZT of 2.04 at 753 K and maximum efficiency of 23.27 at 813 K. In the high-temperature range, through the doping of hafnium (Hf) the nanostructured FeNb0.88Hf0.12Sb recorded the highest ZT value of 1.49 at 1273 K. This was closely followed by Fe1.05Nb0.75Ti0.25Sb, which recorded a ZT value of 1.31 at 1133 K. This makes Fe1.05Nb0.75Ti0.25Sb an attractive substitute for FeNb0.88Hf0.12Sb due to the much lower cost and far greater abundance of titanium (Ti) compared with hafnium.

scholarly journals Review of Sustainable Energies Use in Greenhouses in Greece

2018 ◽  
Vol 5 (4) ◽  
pp. 35
Author(s):  
John Vourdoubas
Keyword(s):  
Power Generation ◽  
Environmental Pollution ◽  
Power Plants ◽  
High Efficiency ◽  
Waste Heat ◽  
Solar Pv ◽  
Northern Greece ◽  
Energy Technologies ◽  
Geothermal Fluids ◽  
Solid Biomass

Greenhouses consume large amounts of energy compared with other agricultural activities contributing to environmental pollution. However the current advances in sustainable energy technologies allow the use of benign energy sources for heat and power generation in them. Various renewable and high efficiency energy technologies are currently used in Greece or could be used in the near future in them. The technologies are mature, reliable and cost-effective. Among them the direct geothermal energy, solid biomass, solar-PV, waste heat re-use and co-generation of heat and power. Their use in small or larger greenhouses reduces the environmental pollution due to fossil fuels use, lowers the dependence on imported fuels, promote investments and create jobs in the local societies. Currently modern hydroponic greenhouses in northern Greece use co-generation of heat and power systems fuelled with natural gas. Heat is used in the greenhouses and the generated power is fed into the grid. Others utilize direct geothermal fluids for space heating. Solid biomass is also used for heating them. All of them can cover all the heating needs in greenhouses. Industrial rejected heat from lignite fired power plants in northern Greece could be easily used in the future for heating them. At the same time the high solar irradiance allows the use of solar photovoltaic (PV) systems for power generation in them. Further integration of sustainable energies in greenhouses in Greece requires the governmental support both in the form of financial subsidies and in removing the existing barriers preventing their use.

Significant Influences of Selenium on the Electrical Properties of Bi2Te3 Compounds Synthesized Using Solid-State Microwave Irradiation

2012 ◽  
Vol 501 ◽  
pp. 126-128 ◽  
Author(s):  
Arej Kadhim ◽  
Arshad Hmood ◽  
Abu Hassan Haslan
Keyword(s):  
Solid State ◽  
Electrical Properties ◽  
Microwave Irradiation ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Microwave Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
P Type

The thermoelectric materials based on p-type Bi2Se3xTe3 (1-x) bulk products and dispersed with x compositions of Se (x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were fabricated using standard solid-state microwave synthesis procedures. The products were characterized by X-ray diffraction (XRD). The XRD characterizations revealed that these products are pure Bi2Te3 and Bi2Se3 with uniform structures. The electrical properties of the Bi2Te3, Bi2Se3 and Bi2Se3xTe3 (1-x) samples were measured in the temperature range of 303–523 K. The highest value of the Seebeck coefficient was 176.3 μV/ K for the Bi2Se0.6Te2.4 sample, but only 149.5 and 87.4 μV/K for the Bi2Te3 and Bi2Se3 samples, respectively.

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