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1
Gogoc, Szymon, e Przemyslaw Data. "Organic Thermoelectric Materials as the Waste Heat Remedy". Molecules 27, n. 3 (2 febbraio 2022): 1016. http://dx.doi.org/10.3390/molecules27031016.
Abstract (sommario):
The primary reason behind the search for novel organic materials for application in thermoelectric devices is the toxicity of inorganic substances and the difficulties associated with their processing for the production of thin, flexible layers. When Thomas Seebeck described a new phenomenon in Berlin in 1820, nobody could have predicted the future applications of the thermoelectric effect. Now, thermoelectric generators (TEGs) are used in watches, and thermoelectric coolers (TECs) are applied in cars, computers, and various laboratory equipment. Nevertheless, the future of thermoelectric materials lies in organic compounds. This paper discusses the developments made in thermoelectric materials, including small molecules, polymers, molecular junctions, and their applications as TEGs and/or TECs.
2
Liu, Qiulin, Guodong Li, Hangtian Zhu e Huaizhou Zhao. "Micro thermoelectric devices: From principles to innovative applications". Chinese Physics B 31, n. 4 (1 aprile 2022): 047204. http://dx.doi.org/10.1088/1674-1056/ac5609.
Abstract (sommario):
Thermoelectric devices (TEDs), including thermoelectric generators (TEGs) and thermoelectric coolers (TECs) based on the Seebeck and Peltier effects, respectively, are capable of converting heat directly into electricity and vice versa. Tough suffering from low energy conversion efficiency and relatively high capital cost, TEDs have found niche applications, such as the remote power source for spacecraft, solid-state refrigerators, waste heat recycling, and so on. In particular, on-chip integrable micro thermoelectric devices (μ-TEDs), which can realize local thermal management, on-site temperature sensing, and energy harvesting under minor temperature gradient, could play an important role in biological sensing and cell cultivation, self-powered Internet of Things (IoT), and wearable electronics. In this review, starting from the basic principles of thermoelectric devices, we summarize the most critical parameters for μ-TEDs, design guidelines, and most recent advances in the fabrication process. In addition, some innovative applications of μ-TEDs, such as in combination with microfluidics and photonics, are demonstrated in detail.
3
Camut, Julia, Eckhard Müller e Johannes de Boor. "Analyzing the Performance of Thermoelectric Generators with Inhomogeneous Legs: Coupled Material–Device Modelling for Mg2X-Based TEG Prototypes". Energies 16, n. 9 (24 aprile 2023): 3666. http://dx.doi.org/10.3390/en16093666.
Abstract (sommario):
Thermoelectric generators (TEGs) possess the ability to generate electrical power from heat. As TEGs are operated under a thermal gradient, inhomogeneous material properties—either by design or due to inhomogeneous material degradation under thermal load—are commonly found. However, this cannot be addressed using standard approaches for performance analysis of TEGs in which spatially homogeneous materials are assumed. Therefore, an innovative method of analysis, which can incorporate inhomogeneous material properties, is presented in this study. This is crucial to understand the measured performance parameters of TEGs and, from this, develop means to improve their longevity. The analysis combines experimental profiling of inhomogeneous material properties, modelling of the material properties using a single parabolic band model, and calculation of device properties using the established Constant Property Model. We compare modeling results assuming homogeneous and inhomogeneous properties to the measurement results of an Mg2(Si,Sn)-based TEG prototype. We find that relevant discrepancies lie in the effective temperature difference across the TE leg, which decreases by ~10%, and in the difference between measured and calculated heat flow, which increases from 2–15% to 9–16% when considering the inhomogeneous material. The approach confirms additional resistances in the TEG as the main performance loss mechanism and allows the accurate calculation of the impact of different improvements on the TEG’s performance.
4
Faheem, Muhammad, Muhammad Abu Bakr, Muntazir Ali, Muhammad Awais Majeed, Zunaib Maqsood Haider e Muhammad Omer Khan. "Evaluation of Efficiency Enhancement in Photovoltaic Panels via Integrated Thermoelectric Cooling and Power Generation". Energies 17, n. 11 (27 maggio 2024): 2590. http://dx.doi.org/10.3390/en17112590.
Abstract (sommario):
Among renewable resources, solar energy is abundant and cost effective. However, the efficiency and performance of photovoltaic panels (PVs) are adversely affected by the rise in the surface temperature of solar cells. This paper analyzes the idea of utilizing thermoelectric modules (TEMs) to enhance the efficiency and performance of PV panels. The proposed hybrid solar thermoelectric generation (HSTEG) system employs TEMs as thermoelectric coolers (TECs) to enhance panel efficiency and as thermoelectric generators (TEGs) to convert excess heat into additional electricity. This study includes an extensive evaluation of the proposed idea using MATLAB Simulink and experimental validation in indoor as well as outdoor environments. The use of TECs for the active cooling of the PV system leads to an increase in its efficiency by 9.54%. Similarly, the passive cooling by TECs along with the additional power generated by the TEGs from the excessive heat led to an increase in the efficiency of the PV system of 15.50%. The results demonstrate the HSTEG system’s potential to significantly improve PV panel efficiency and energy generation, offering a promising avenue for advancing solar energy technology.
5
Sanin-Villa, Daniel, Oscar Danilo Montoya e Luis Fernando Grisales-Noreña. "Material Property Characterization and Parameter Estimation of Thermoelectric Generator by Using a Master–Slave Strategy Based on Metaheuristics Techniques". Mathematics 11, n. 6 (9 marzo 2023): 1326. http://dx.doi.org/10.3390/math11061326.
Abstract (sommario):
Thermoelectric generators (TEGs) have gained significant interest as a sustainable energy source, due to their ability to convert thermal energy into electrical energy through the Seebeck effect. However, the power output of TEGs is highly dependent on the thermoelectric material properties and operational conditions. Accurate modeling and parameter estimation are essential for optimizing and designing TEGs, as well as for integrating them into smart grids to meet fluctuating energy demands. This work examines the challenges of accurate modeling and parameter estimation of TEGs and explores various optimization metaheuristics techniques to find TEGs parameters in real applications from experimental conditions. The paper stresses the importance of determining the properties of TEGs with precision and using parameter estimation as a technique for determining the optimal values for parameters in a TEG mathematical model that represent the actual behavior of a thermoelectric module. This methodological approach can improve TEG performance and aid in efficient energy supply and demand management, thus reducing the reliance on traditional fossil fuel-based power generation.
6
Attar, Alaa, Mohamed Rady, Abdullah Abuhabaya, Faisal Albatati, Abdelkarim Hegab e Eydhah Almatrafi. "Performance Assessment of Using Thermoelectric Generators for Waste Heat Recovery from Vapor Compression Refrigeration Systems". Energies 14, n. 23 (6 dicembre 2021): 8192. http://dx.doi.org/10.3390/en14238192.
Abstract (sommario):
This article reports on an experimental analysis and performance assessment of using thermoelectric generators (TEGs) for waste heat recovery from residential vapor compression refrigeration systems. The analysis shows that there is a good opportunity for waste heat recovery using TEGs by de-superheating refrigerant after the compressor. Design and manufacturing of a de-superheater unit consisting of a tube and plate heat exchanger and thermoelectric generator modules (HE-TEGs) have been performed and integrated in an experimental test rig of R134a refrigeration cycle. Experimental assessment of the performance parameters, as compared to the basic refrigeration system, reveals that the overall coefficient of performance (COP) using HE-TEGs desuperheater unit increases by values ranging from 17% to 32% depending on the condenser and evaporator loads. Exergy analysis shows that the enhancement is attributed to reduction in the exergy destruction in the condenser and compressor due to lower values of condenser pressure and pressure ratio of the compressor. The output power of the HE-TEGs unit is found to be sufficient for driving the TEGs heat sinks air cooling fan, thus providing a passive de-superheating system without an additional external source of electricity. Further enhancement of the refrigeration cycle performance can be achieved by installation of additional HE-TEGs units.
7
Singh, Yogesh, Satyendra kumar Singh e Purnima Hazra. "Future Prospect of Rare Earth Element Free Materials for Thermoelectric Generators". ECS Transactions 107, n. 1 (24 aprile 2022): 453–64. http://dx.doi.org/10.1149/10701.0453ecst.
Abstract (sommario):
Almost all traditional energy sources are on the point of rapid depletion due to over use. There is demand for alternative renewable energy sources, and thermoelectric generators (TEGs) are one of the rising solutions. TEGs are a new class of solid-state devices that transform waste heat energy directly into electricity using Seebeck effect. The efficiency of TEGs is governed by dimensionless quantity called Figure of merit (ZT), which plays an important role to determine the overall sustainability of TEGs. Traditional thermoelectric generators have a poor efficiency (12-20%), which is a disadvantage. To obtain higher value of ZT, the prime emphasis is given towards material engineering as the efficiency solely depends on the materials selection. The investigation is on earth-abundant, cost-effective, low-toxic innovative nanomaterials. In addition, the paper covers various elements for TEGs with prime focus towards rare earth free materials and their emerging trends.
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Mashburn, Paulla, Jodie Ecklund e Jeffrey Riley. "Do Heparinase Thrombelastographs Predict Postoperative Bleeding?" Journal of ExtraCorporeal Technology 28, n. 4 (dicembre 1996): 185–90. http://dx.doi.org/10.1051/ject/1996284185.
Abstract (sommario):
Postoperative hemorrhage is a major cause of morbidity and mortality in patients who undergo cardiopulmonary bypass (CPB). The thrombelastograph (TEG) is a viscoelastic whole blood test that measures clot dynamics from clot formation through clot lysis. Previous studies have shown that post-bypass TEGs are accurate predictors of postoperative bleeding. TEGs from heparinized blood reversed with heparinase may be employed during CPB to evaluate coagulation. CPB heparinase TEGs may allow for earlier recognition of patients who may bleed after bypass. Earlier TEG analysis would allow targeting of specific therapies to begin before the patient bleeds excessively. Fifty-four heparinase TEGs during warming and fifty-four native TEGs post-protamine administration were collected. Parameters evaluated were R, K, alpha angle, MA, MA60, coagulation index, activated clotting time. hematocrit, prothrombin time, partial thromboplastin time, thrombin time, fibrinogen concentration, platelet count, blood loss during and after CPB, and blood and blood product administration. Coagulation indexes for CPB heparinase TEGs that were less than -2 or heparinase TEGs that were fibrinolytic were 87% accurate in predicting patients with excessive intraoperative blood loss, but were not predictive of blood product administration. The sensitivity was 12.5% and the specificity was I 00% in predicting excessive intraoperative bleeding. Post-protamine coagulation index inversely correlated with intraoperative red blood cell administration (r=-0.403, p<0.05), but was not predictive. Patients with fibrinolytic TEGs required blood products to compensate for expected blood loss associated with the fibrinolytic state. Simultaneous routine coagulation tests did not correlate significantly with blood loss or blood product administration, nor were they predictive. The findings of this study suggest that the presence of fibrinolysis in either a heparinase TEG on bypass or a post-protamine TEG is the most important predictor of blood and blood product administration. But, since only 20% of the patients in the study exhibited fibrinolytic TEGs, a study that included a much larger sample of patients would need to be done to confirm this finding.
9
Faraj, Jalal, Wassim Salameh, Ahmad Al Takash, Georges El Achakr, Hicham El Hajj, Cathy Castelain e Mahmoud Khaled. "Dual harvesting from exhaust gas of diesel generators using thermoelectric generators and cold water tank". Journal of Physics: Conference Series 2754, n. 1 (1 maggio 2024): 012021. http://dx.doi.org/10.1088/1742-6596/2754/1/012021.
Abstract (sommario):
Abstract The present work concerns a dual harvesting concept applied to exhaust gas of Diesel generators using thermoelectric generators and cold water tank. To proceed, a simplified thermal modelling is developed and appropriate parametric analysis of power generation with the TEGs and heat recovered is conducted in function of the Diesel generator power and the TEG thermal conductivity and thickness. It was shown that powers up to 534 W can be generated with the TEGs and heat recovery rates up to 4463 W can be obtained for a Diesel generator power of 125 kW. Also, it was shown that the temperature difference across the TEGs and the power generated increase exponentially when the Diesel generator power and ratio of thickness to thermal conductivity of TEGs increase.
10
Morais, Flávio, Pedro Carvalhaes-Dias, Luís Duarte, Anderson Spengler, Kleber de Paiva, Thiago Martins, Andreu Cabot e José Siqueira Dias. "Optimization of the TEGs Configuration (Series/Parallel) in Energy Harvesting Systems with Low-Voltage Thermoelectric Generators Connected to Ultra-Low Voltage DC–DC Converters". Energies 13, n. 9 (6 maggio 2020): 2297. http://dx.doi.org/10.3390/en13092297.
Abstract (sommario):
Solar radiation and human activity generate ubiquitous temperature gradients that could be harvested by thermoelectric generators (TEGs). However, most of these temperature gradients are in the range of very few degrees and, while TEGs are able to harvest them, the resulting output voltages are extremely small (a few hundreds of mV), and DC–DC converters are necessary to boost them to usable levels. Impedance matching between TEGs and DC–DC converter plays a fundamental role in the energy harvesting efficiency. Therefore, it is essential to determine the output power of the system in different configurations, in order to decide on the optimum TEG connection. Here, we present an electronic circuit to measure the maximum power that can be harvested with low-voltage TEGs connected to a DC–DC converter. The developed circuit is an electronic controlled load that drains the maximum current from the output of the DC–DC converter while maintaining its output voltage at the maximum allowed value. Using a mechanical set-up able to apply precise low temperature gradients between the hot and cold side of the TEGs, experimental data using different configurations of TEGs are obtained. The measured results show that, for ultra-low voltages, the TEG ensemble’s output impedance plays an important role not only in the amount of the energy scavenged, but also in the onset temperature of the energy harvesting.
11
Kalyani, Chinchinada V. S. L., Motepalli Sunil Kumar e Tella Nagaraju. "TEG Cascaded Solar PV System with Enhanced Efficiency by Using the PSO MPPT Boost Converter". International Journal of Research in Engineering, Science and Management 3, n. 11 (27 novembre 2020): 105–10. http://dx.doi.org/10.47607/ijresm.2020.384.
Abstract (sommario):
Thermoelectric generators (TEGs) are used in small power applications to generate electrical energy from waste heats. Maximum power is obtained when the connected load to the ends of TEGs matches their internal resistance. However, impedance matching cannot always be ensured. Therefore, TEGs operate at lower efficiency. For this reason, maximum power point tracking (MPPT) algorithms are utilized. In this study, both TEGs and a boost converter with MPPT were modeled together. Detailed modeling, simulation, and verification of TEGs depending on the Seebeck coefficient, the hot/cold side temperatures, and the number of modules in MATLAB/Simulink were carried out. In addition, a boost converter having a particle swarm optimization (PSO) MPPT algorithm was added to the TEG modeling. After the TEG output equations were determined, the TEG modeling was performed based on manufacturer data sheets. Thanks to the TEG model and the boost converter with PSO MPPT, the maximum power was tracked with a value of 98.64% and the power derived from the TEG was nearly unaffected by the load changes. The power outputs obtained from the system with and without MPPT were compared to emphasize the importance of MPPT. These simulation values were verified by using an experimental setup. Ultimately, the proposed modeling provides a system of TEGs and a boost converter having PSO MPPT.
12
Kosugi, Ryouji, T. Sakata, Y. Sakuma, K. Suzuki, Tsutomu Yatsuo, H. Matsuhata, Hirotaka Yamaguchi et al. "Voltage-Current (V-I) Characteristics of 1.5kV Class pn Junctions with p-Well Structures on (0001) 4H-SiC". Materials Science Forum 615-617 (marzo 2009): 683–86. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.683.
Abstract (sommario):
We have fabricated the four pn-type junction TEGs (Test Element Groups) having different structure. Those TEGs are close to the double-implanted (Di) MOSFETs, step by step from the simple pn diode. Voltage-current (V-I) characteristics of the hundred TEGs having p-well structure show similar blocking characteristics of those of simple pn diodes on the same wafer. This indicates that the p-well structure itself does not cause a significant deterioration on the blocking yield. On the other hand, the yield is significantly influenced by the annealing condition for ion-implanted layer. The oxide-related hard breakdown on the JFET region dominates the blocking yield. The reach-through breakdown of the TEGs having the n+ region within each p-well becomes largely suppressed by the high-temperature and short-time annealing.
13
Bayendang, Nganyang Paul, Mohamed Tariq Kahn e Vipin Balyan. "Thermoelectric Generators (TEGs) modules—Optimum electrical configurations and performance determination". AIMS Energy 10, n. 1 (2022): 102–30. http://dx.doi.org/10.3934/energy.2022007.
Abstract (sommario):
<abstract> <p>Renewable energy technologies such as solar, thermal, wind, hydro, bio-fuels, fuel cells etc. are becoming trendy and being commissioned in large-scales, due to their environmental friendliness and energy sustainability. This manuscript focuses on alternative energy based-on thermoelectricity, particularly thermoelectric generators (TEGs). From the literature review, there is less emphasis on how multiple TEGs can be best configured electrically for optimum operations. In light of this, Matlab/Simulink were employed to institute a unique theoretical framework, that can easily be comprehensively used to simulate thermoelectricity parameters, with focus to determine TEG modules (of any quantity/configuration) optimal resistance matching and performance. The principal findings of the study are; 1) the effects of TEGs internal resistance, which proportionally causes output voltage drop and power loss as well as efficiency loss and 2) TEG modules may not be connected anyhow in series and or in parallel, but in a setup that gives a total electrical resistance that matches the load electrical resistance. Thus, TEGs should be a) of the same model with the same or approximate internal resistance, b) in a configuration whereby the TEGs total resistance equals the load resistance, as doing so ensures maximum power is transferred between the source (TEGs) and the electrical load and c) preferably be in a symmetrical electrical configuration. A symmetrical electrical configuration ensures ⅰ) the TEG modules total output resistance, irrespective of the quantity used, approximates that of a single TEG, with the overall TEG modules simply becoming now one large powerful TEG having an equivalent resistance of a single TEG and ⅱ) the TEGs power, voltage and current operations are optimal.</p> </abstract>
14
Kumar, Babu, Subramanian, Bandla, Thakor, Ramakrishna e Wei. "The Design of a Thermoelectric Generator and Its Medical Applications". Designs 3, n. 2 (26 aprile 2019): 22. http://dx.doi.org/10.3390/designs3020022.
Abstract (sommario):
Growing energy demands are driving people to generate power in every possible way. New energy sources are needed to plug the energy gap. There is a growing interest in distributed energy generation due to its remarkable advantages such as flexibility, reliability, adaptability and minimal transmission losses. Thermoelectric generators (TEGs) are one such distributed power source that relies on thermal energy for electricity generation. The current review focusses on the design and optimization of TEGs to maximize the power output from the available thermal sources. The basic principle of thermoelectricity generation and suitable architecture for specific applications are explained with an overview of materials and manufacturing processes. Various cooling techniques to dissipate heat from the cold side and their influence on overall efficiency are reviewed in this work. Applications of TEGs for powering biomedical sensors have been discussed in detail. Recent advancements in TEGs for various implantable devices and their power requirements are evaluated. The exploitation of TEGs to generate power for wearable sensors has been presented, along with published experimental data. It is envisioned that this study will provide profound knowledge on TEG design for specific applications, which will be helpful for future endeavours.
15
Stathopoulos, Panagiotis, e Javier Fernàndez-Villa. "On the Potential of Power Generation from Thermoelectric Generators in Gas Turbine Combustors". Energies 11, n. 10 (16 ottobre 2018): 2769. http://dx.doi.org/10.3390/en11102769.
Abstract (sommario):
Thermoelectric generators (TEGs) offer an attractive power generation option. They have no moving parts, are robust and emit no pollutants. The current work explores the integration of high temperature TEGs in gas turbine combustors. The latter have a thermal shield at their inner surface to protect them against high temperatures. This is supplemented by convective and film cooling. This work studies the replacement of the thermal shield with high temperature TEGs and evaluates their techno-economic potential. A gas turbine model is developed and validated to compute the fuel and air flow rate in the combustion chamber. A heat transfer model is subsequently implemented to compute the temperature distribution inside the combustor wall, on which the TEG is constructed. The investment in TEGs is then analyzed for peaker, intermediate load and base load gas turbines. The work concludes with a sensitivity analysis of the investment economic performance. It is concluded that, despite the low power generation, the installation of TEGs makes economic sense, even if their price becomes 50% higher than current estimations. It is also concluded that electricity prices have a much stronger effect on the economic viability of the investment than the price of the generators.
16
Li, Yihuai, Zihua Wu, Huaqing Xie, Dingcong Tang, Yuanyuan Wang e Zhen Li. "The preparation, characterization and application of glycol aqueous base graphene oxide nanofluid". MATEC Web of Conferences 238 (2018): 02001. http://dx.doi.org/10.1051/matecconf/201823802001.
Abstract (sommario):
Enhancement of the heat transfer of the cold side is one of the approaches to improve the performance of thermoelectric generator systems (TEGs). In order to investigate viability and further performance of the TEG for waste heat recovery in industry area, a small low-temperature waste heat thermoelectric generator setup has been constructed with graphene oxide (GO) nanofluids as coolants in the paper. The results showed excellent stability of GO nanofluids through the preparation of two-step method to be applied in the TEGs .The highest open output voltage of TEG system were obtained by 0.15% weight fraction of GO nanofluids as coolant when the temperature difference (△T) was designed at 95K and the hot side temperature was fixed at 373K in the TEGs. Compared with conventional glycol-water base fluid as coolant, the highest open voltage enhancement ratio has reached 65.26% in the TEGs.
17
Schafaschek, Germano, Laurent Hardouin e Jörg Raisch. "Optimal control of timed event graphs with resource sharing and output-reference update". at - Automatisierungstechnik 68, n. 7 (26 luglio 2020): 512–28. http://dx.doi.org/10.1515/auto-2020-0051.
Abstract (sommario):
AbstractTimed event graphs (TEGs) are a subclass of timed Petri nets that model synchronization and delay phenomena, but not conflict or choice. We consider a scenario where a number of TEGs share one or several resources and are subject to changes in their output-reference signals. Because of resource sharing, the resulting overall discrete event system is not a TEG. We propose a formal method to determine the optimal control input for such systems, where optimality is in the sense of the widely adopted just-in-time criterion. Our approach is based on a prespecified priority policy for the TEG components of the overall system. It builds on existing control theory for TEGs, which exploits the fact that, in a suitable mathematical framework (idempotent semirings such as the max-plus or the min-plus algebra), the temporal evolution of TEGs can be described by a set of linear time-invariant equations.
18
Kishore, Ravi, Roop Mahajan e Shashank Priya. "Combinatory Finite Element and Artificial Neural Network Model for Predicting Performance of Thermoelectric Generator". Energies 11, n. 9 (24 agosto 2018): 2216. http://dx.doi.org/10.3390/en11092216.
Abstract (sommario):
Thermoelectric generators (TEGs) are rapidly becoming the mainstream technology for converting thermal energy into electrical energy. The rise in the continuous deployment of TEGs is related to advancements in materials, figure of merit, and methods for module manufacturing. However, rapid optimization techniques for TEGs have not kept pace with these advancements, which presents a challenge regarding tailoring the device architecture for varying operating conditions. Here, we address this challenge by providing artificial neural network (ANN) models that can predict TEG performance on demand. Out of the several ANN models considered for TEGs, the most efficient one consists of two hidden layers with six neurons in each layer. The model predicted TEG power with an accuracy of ±0.1 W, and TEG efficiency with an accuracy of ±0.2%. The trained ANN model required only 26.4 ms per data point for predicting TEG performance against the 6.0 minutes needed for the traditional numerical simulations.
19
Nicu, Ionut Cristi, Letizia Elia, Lena Rubensdotter, Hakan Tanyaş e Luigi Lombardo. "Multi-hazard susceptibility mapping of cryospheric hazards in a high-Arctic environment: Svalbard Archipelago". Earth System Science Data 15, n. 1 (31 gennaio 2023): 447–64. http://dx.doi.org/10.5194/essd-15-447-2023.
Abstract (sommario):
Abstract. The Svalbard Archipelago represents the northernmost place on Earth where cryospheric hazards, such as thaw slumps (TSs) and thermo-erosion gullies (TEGs) could take place and rapidly develop under the influence of climatic variations. Svalbard permafrost is specifically sensitive to rapidly occurring warming, and therefore, a deeper understanding of TSs and TEGs is necessary to understand and foresee the dynamics behind local cryospheric hazards' occurrences and their global implications. We present the latest update of two polygonal inventories where the extent of TSs and TEGs is recorded across Nordenskiöld Land (Svalbard Archipelago), over a surface of approximately 4000 km2. This area was chosen because it represents the most concentrated ice-free area of the Svalbard Archipelago and, at the same time, where most of the current human settlements are concentrated. The inventories were created through the visual interpretation of high-resolution aerial photographs as part of our ongoing effort toward creating a pan-Arctic repository of TSs and TEGs. Overall, we mapped 562 TSs and 908 TEGs, from which we separately generated two susceptibility maps using a generalised additive model (GAM) approach, under the assumption that TSs and TEGs manifest across Nordenskiöld Land, according to a Bernoulli probability distribution. Once the modelling results were validated, the two susceptibility patterns were combined into the first multi-hazard cryospheric susceptibility map of the area. The two inventories are available at https://doi.org/10.1594/PANGAEA.945348 (Nicu et al., 2022a) and https://doi.org/10.1594/PANGAEA.945395 (Nicu et al., 2022b).
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Cho, Young Hoo, Jaehyun Park, Naehyuck Chang e Jaemin Kim. "Comparison of Cooling Methods for a Thermoelectric Generator with Forced Convection". Energies 13, n. 12 (19 giugno 2020): 3185. http://dx.doi.org/10.3390/en13123185.
Abstract (sommario):
A thermoelectric generator (TEG) is a clean electricity generator from a heat source, usually waste heat. However, it is not as widely utilized as other electricity generators due to low conversion efficiency from heat to electricity. One approach is a system-level net power optimization for a TEG system composed of TEGs, heat sink, and fans. In this paper, we propose airflow reuse after cooling preceding TEGs to maximize system net power. For the accurate system net power, we model the TEG system, air, and heat source with proper dimension and material characteristics, and simulate with a computational fluid dynamics program. Next, the TEG power generation and the fan power consumption are calculated in consideration of the Seebeck coefficient and internal electrical resistance varying with hot and cold side temperatures. Finally, we find the optimal number of TEGs and fan speed generating the most efficient system net power in various TEG systems. The results show that the system with a side fan with a specific number of TEGs provides a system net power up to 58.6% higher than when with a top fan. The most efficient system net power with the side fan increases up to four TEGs generating 1.907 W at 13,000 RPM.
21
Choi, T., J. H. Lee e T. Y. Kim. "Numerical analysis of semiconductor-based energy conversion technologies for offshore applications". IOP Conference Series: Materials Science and Engineering 1294, n. 1 (1 dicembre 2023): 012005. http://dx.doi.org/10.1088/1757-899x/1294/1/012005.
Abstract (sommario):
Abstract This study analyzes the physical principles and characteristics of thermoelectric energy conversion phenomena utilizing p-n semiconductor couples to propose a design methodology for thermoelectric generators (TEGs) capable of energy recovery in marine environments. To design TEGs with practical power generation and energy conversion efficiency, the development of a numerical analysis model that can predict and analyze the behavior characteristics of TEGs is required. We present the necessary conditions for a numerical analysis model that simulates the generation characteristics of TEGs at the system level, along with a comparison and analysis of experimental results. The electrical connection method of the thermoelectric modules (TEMs) significantly affects the power generation performance of TEGs; however, there is a lack of research on the electrical connections between TEMs in existing studies. This paper examines the reasons for performance changes due to electrical connections between TEMs and proposes an optimal electrical connection method. Additionally, it is demonstrated that improving the thermal flow distribution within the TEG can enhance system performance and maximize the effects of electrical connections between TEMs. We analyze the characteristics of technologies that can improve the level of thermal flow distribution within the TEG, such as finned and porous structures, and present optimal utilization strategies.
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Jang, Wonjun, Hyun Cho, Kyungwho Choi e Yong Park. "Manipulation of p-/n-Type Thermoelectric Thin Films through a Layer-by-Layer Assembled Carbonaceous Multilayer Structure". Micromachines 9, n. 12 (28 novembre 2018): 628. http://dx.doi.org/10.3390/mi9120628.
Abstract (sommario):
Recently, with the miniaturization of electronic devices, problems with regard to the size and capacity of batteries have arisen. Energy harvesting is receiving significant attention to solve these problems. In particular, the thermoelectric generator (TEG) is being studied for its ability to harvest waste heat energy. However, studies on organic TEGs conducted thus far have mostly used conductive polymers, making the application range of TEGs relatively narrow. In this study, we fabricated organic TEGs using carbonaceous nanomaterials (i.e., graphene nanoplatelet (GNP) and single-walled carbon nanotube (SWNT)) with polyelectrolytes (i.e., poly(vinyl alcohol) (PVA) and poly (diallyldimethyl ammonium chloride) (PDDA)) via layer-by-layer (LbL) coating on polymeric substrates. The thermoelectric performance of the carbonaceous multilayer structure was measured, and it was confirmed that the thermoelectric performance of the TEG in this study was not significantly different from that of the existing organic TEG fabricated using the conductive polymers. The 10 bilayer SWNT thin films with polyelectrolyte exhibited a thermopower of −14 μV·K−1 and a power factor of 25 μW·m−1K−2. Moreover, by simply changing the electrolyte, p- or n-type TEGs could be easily fabricated with carbonaceous nanomaterials via the LbL process. Also, by just changing the electrolyte, p- or n-type of TEGs could be easily fabricated with carbonaceous nanomaterials with a layer-by-layer process.
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Bayendang, Nganyang Paul, Mohamed Tariq Kahn e Vipin Balyan. "Thermoelectric Generators (TEGs) and Thermoelectric Coolers (TECs) Modeling and Optimal Operation Points Investigation". Advances in Science, Technology and Engineering Systems Journal 7, n. 1 (febbraio 2022): 60–78. http://dx.doi.org/10.25046/aj070107.
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Fathy, Ahmed, Hegazy Rezk, Dalia Yousri, Essam H. Houssein e Rania M. Ghoniem. "Parameter Identification of Optimized Fractional Maximum Power Point Tracking for Thermoelectric Generation Systems Using Manta Ray Foraging Optimization". Mathematics 9, n. 22 (21 novembre 2021): 2971. http://dx.doi.org/10.3390/math9222971.
Abstract (sommario):
Thermoelectric generation systems (TEGSs) are used to convert temperature difference and heat flow into DC power based on the Seebeck theorem. The basic unit of TEGS is the thermoelectric module (TEM). TEGSs have gained increasing interest in the research fields of sustainable energy. The output power from TEM is mostly reliant on differential temperature between the hot and cold sides of the TEM added to the value of the load. As such, a robust MPPT strategy (MPPTS) is required to ensure that the TEGS is operating near to the MPP while varying the operating conditions. Two main drawbacks may occur in the conventional MPPTSs: low dynamic response, such as in the incremental resistance (INR) method, and oscillations around MPP at steady state, such as in the hill climbing (HC) method. In the current research work, an optimized fractional MPPTS is developed to improve the tracking performance of the TEGS, and remove the two drawbacks of the conventional MPPTSs. The proposed strategy is based on fractional order control (FOC). The main advantage of FOC is that it offers extra flexible time and frequency responses of the control system consent for better and robust performance. The optimal parameters of the optimized fractional MPPTS are identified by a manta ray foraging optimization (MRFO). To verify the robustness of the MRFO, the obtained results are compared with ten other algorithms: particle swarm optimization; whale optimization algorithm; Harris hawks optimization; heap-based optimizer; gradient-based optimizer; grey wolf optimizer; slime mould algorithm; genetic algorithm; seagull optimization algorithm (SOA); and tunicate swarm algorithm. The maximum average cost function of 4.92934 kWh has been achieved by MRFO, followed by SOA (4.5721 kWh). The lowest STD of 0.04867 was also accomplished by MRFO. The maximum efficiency of 99.46% has been obtained by MRFO, whereas the lowest efficiency of 74.01% was obtained by GA. Finally, the main findings proved the superiority of optimized fractional MPPTS compared with conventional methods for both steady-state and dynamic responses.
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Hakim, Imansyah Ibnu, Nandy Putra e Mohammad Usman. "Analysis of the use of thermoelectric generator and heat pipe for waste heat utilization". E3S Web of Conferences 67 (2018): 02057. http://dx.doi.org/10.1051/e3sconf/20186702057.
Abstract (sommario):
Waste heat recovery is one way to reduce the use of fossil fuels, one of them is by using thermoelectric generator to convert waste heat into Thermoelectric Generator (TEGs) is a module that can convert heat into electrical power directly, using Seebeck effect and Peltier effect as its working principle, so it can increase efficiency of energy consumption by utilizing waste heat from an instrument that generate waste heat. The focus of this research is to find the output voltage of TEG by utilizing the temperature difference on the cold side and the heat side of the TEGs. The heat side of the module will be given heat from the heater as a simulation of the heat from hot water, and on the cold side heat pipes will be used to remove the heat on the cold side of TEGs. The result, output voltage that generated by using 4 module TEGs that arranged to Thermal Series - Series Circuit and using 2 heat pipes is 2.1-volt, and then it is possible to use for phone charger.
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Chávez Urbiola, Edgar Arturo, e Yuri Vorobiev. "Investigation of Solar Hybrid Electric/Thermal System with Radiation Concentrator and Thermoelectric Generator". International Journal of Photoenergy 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/704087.
Abstract (sommario):
An experimental study of a solar-concentrating system based on thermoelectric generators (TEGs) was performed. The system included an electrical generating unit with 6 serially connected TEGs using a traditional semiconductor material, Bi2Te3, which was illuminated by concentrated solar radiation on one side and cooled by running water on the other side. A sun-tracking concentrator with a mosaic set of mirrors was used; its orientation towards the sun was achieved with two pairs of radiation sensors, a differential amplifier, and two servomotors. The hot side of the TEGs at midday has a temperature of around 200°C, and the cold side is approximately 50°C. The thermosiphon cooling system was designed to absorb the heat passing through the TEGs and provide optimal working conditions. The system generates 20 W of electrical energy and 200 W of thermal energy stored in water with a temperature of around 50°C. The hybrid system studied can be considered as an alternative to photovoltaic/thermal systems, especially in countries with abundant solar radiation, such as Mexico, China, and India.
27
Chukwurah, Ugochukwu, e Gordon McTaggart-Cowan. "Harvesting Electric Energy Using Thermoelectric Generators in a Residential Heating Application". Energies 17, n. 11 (25 maggio 2024): 2562. http://dx.doi.org/10.3390/en17112562.
Abstract (sommario):
Biomass combustors provide space heating by converting chemical energy in woody biomass into low-temperature thermal energy. Thermoelectric generators (TEGs) can generate electricity from the heat flux without significantly reducing heating performance. However, most current TEGs are small (40 mm × 40 mm), requiring many TEG elements to generate useful power from a biomass combustion-based space heater. This work compares the electrical generation potential of an array of small TEGs with a larger (80 mm × 120 mm) TEG in a vertical configuration representative of a residential heating appliance. An experimental facility was developed for various representative cold-side ducts and controllable hot-side temperature and cooling airflows, and the Taguchi method was used to evaluate the impacts of temperature, airspeed, and ducting configurations. The results indicate that temperature and airspeed significantly influence TEG power, while ducting configurations have an insignificant influence. The large TEG achieved more consistent temperatures but produced lower power than an array of smaller TEGs with the same total area. The study emphasizes optimizing TEG design and operating conditions to enhance electricity generation efficiency in space heating combustors.
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Mizoshiri, Mizue, Masashi Mikami e Kimihiro Ozaki. "Fabrication Process of Antimony Telluride and Bismuth Telluride Micro Thermoelectric Generator". International Journal of Automation Technology 9, n. 6 (5 novembre 2015): 612–18. http://dx.doi.org/10.20965/ijat.2015.p0612.
Abstract (sommario):
This paper describes the process of fabricating micro thermoelectric generators (μ-TEGs) based on antimony telluride (Sb-Te) and bismuth telluride (Bi-Te). These materials have excellent thermoelectric (TE) conversion properties. The deposition and patterning processes for thermoelectric films are key techniques in the fabrication of μ-TEGs. However, it is difficult to form TE micropatterns using conventional semiconductor technologies because Sb-Te and Bi-Te are brittle and difficult to etch. Therefore, a semiconductor fabrication process is developed for TE film patterning. Here, various processes for depositing Sb-Te and Bi-Te TE films are described. Then, the combinations of the deposition and patterning techniques are reviewed. Finally, the generation properties of the μ-TEGs are summarized.
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KOTLERMAN, LILI, IDO DAGAN, BERNARDO MAGNINI e LUISA BENTIVOGLI. "Textual entailment graphs". Natural Language Engineering 21, n. 5 (23 giugno 2015): 699–724. http://dx.doi.org/10.1017/s1351324915000108.
Abstract (sommario):
AbstractIn this work, we present a novel type of graphs for natural language processing (NLP), namely textual entailment graphs (TEGs). We describe the complete methodology we developed for the construction of such graphs and provide some baselines for this task by evaluating relevant state-of-the-art technology. We situate our research in the context of text exploration, since it was motivated by joint work with industrial partners in the text analytics area. Accordingly, we present our motivating scenario and the first gold-standard dataset of TEGs. However, while our own motivation and the dataset focus on the text exploration setting, we suggest that TEGs can have different usages and suggest that automatic creation of such graphs is an interesting task for the community.
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Farhat, Obeida, Mahmoud Khaled, Jalal Faraj, Farouk Hachem e Cathy Castelain. "Hybridization of heat recovery from exhaust gas of boilers using thermoelectric generators". Journal of Physics: Conference Series 2754, n. 1 (1 maggio 2024): 012023. http://dx.doi.org/10.1088/1742-6596/2754/1/012023.
Abstract (sommario):
Abstract This study investigates the possibilities for energy recovery and environmental effect reduction of waste heat, a consequence of industrial activities. The main objective of the work is to integrate thermoelectric generators (TEGs) into industrial hybrid waste heat recovery system. The study consists of combining TEGs modules with a boiler waste heat recovery system with Rockwool insulation, taking into consideration variables like thermal resistance, power output, water temperature, and energy conversion efficiency. The results show that TEG placement has a major impact on system performance. One of the promising configuration is TEGs placed close to heat source, especially outside exhaust pipe outer walls, where electrical power up to 27 W can be generated and heat of 4215 W can be recovered from the exhaust gas.
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El Oualid, Soufiane, Francis Kosior, Gerhard Span, Ervin Mehmedovic, Janina Paris, Christophe Candolfi e Bertrand Lenoir. "Influence of Thermoelectric Properties and Parasitic Effects on the Electrical Power of Thermoelectric Micro-Generators". Energies 15, n. 10 (19 maggio 2022): 3746. http://dx.doi.org/10.3390/en15103746.
Abstract (sommario):
Heat recovery systems based on thermoelectric micro-generators (µ-TEGs) can play a significant role in the development of wireless, energetically autonomous electronics. However, to date, the power density recovered for low temperature differences using µ-TEGs is limited to a few micro-watts or less, which is still insufficient to power a wide-range of wireless devices. To develop more efficient µ-TEGs, material, device and system requirements must be considered simultaneously. In this study, an innovative design of an in-plane µ-TEG integrating bismuth telluride forming sinusoidal-shaped trenches is reported. Using 3D numerical modelling, the influence of boundary conditions, parasitic effects (electrical and thermal contact resistances), and transport properties of thermoelectric materials on the output power of these µ-TEGs are investigated in detail for a small temperature difference of 5 K between the hot and cold sources. Compared to wavy-shaped trenches, this novel shape enables enhancing the output power. The results show that either the thermal conductivity or the Seebeck coefficient of the active n- and p-type semiconductors is the key parameter that should be minimized or maximized, depending on the magnitude of the parasitic effects.
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Pataki, Nathan, Pietro Rossi e Mario Caironi. "Solution processed organic thermoelectric generators as energy harvesters for the Internet of Things". Applied Physics Letters 121, n. 23 (5 dicembre 2022): 230501. http://dx.doi.org/10.1063/5.0129861.
Abstract (sommario):
Organic thermoelectric generators (TEGs) are a prospective class of versatile energy-harvesters that can enable the capture of low-grade heat and provide power to the growing number of microelectronic devices and sensors in the Internet of Things. The abundance, low-toxicity, and tunability of organic conducting materials along with the scalability of the fabrication techniques promise to culminate in a safe, low-cost, and adaptable device template for a wide range of applications. Despite recent breakthroughs, it is generally recognized that significant advances in n-type organic thermoelectric materials must be made before organic TEGs can make a real impact. Yet, in this perspective, we make the argument that to accelerate progress in the field of organic TEGs, future research should focus more effort into the design and fabrication of application-oriented devices, even though materials have considerable room for improvement. We provide an overview of the best solution-processable organic thermoelectric materials, design considerations, and fabrication techniques relevant for application-oriented TEGs, followed by our perspective on the insight that can be gained by pushing forward with device-level research despite suboptimal materials.
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Bayendang, Nganyang Paul, Mohamed Tariq Kahn e Vipin Balyan. "A Structural Review of Thermoelectricity for Fuel Cell CCHP Applications". Journal of Energy 2020 (21 luglio 2020): 1–23. http://dx.doi.org/10.1155/2020/2760140.
Abstract (sommario):
This article starts by introducing the ongoing South Africa electricity crisis followed by thermoelectricity, in which eighteen miscellaneous applicable case studies are structurally analysed in detail. The aim is to establish best practices for the R&D of an efficient thermoelectric (TE) and fuel cell (FC) CCHP system. The examined literature reviews covered studies that focused on the thermoelectricity principle, highlighting TE devices’ basic constructions, TEGs and TECs as well as investigations on the applications of thermoelectricity with FCs, whereby thermoelectricity was applied to recover waste heat from FCs to boost the power generation capability by ~7–10%. Furthermore, nonstationary TEGs whose generated power can be increased by pulsing the DC-DC power converter showed that an output power efficiency of 8.4% is achievable and that thicker TEGs with good area coverage can efficiently harvest waste heat energy in dynamic applications. TEG and TEC exhibit duality and the higher the TEG temperature difference, the more the generated power—which can be stabilised using the MPPT technique with a 1.1% tracking error. A comparison study of TEG and solar energy demonstrated that TEG generates more power compared to solar cells of the same size, though more expensively. TEG output power and efficiency in a thermal environment can be maximised simultaneously if its heat flux is stable but not the case if its temperature difference is stable. The review concluded with a TEC LT-PEM-FC hybrid CCHP system capable of generating 2.79 kW of electricity, 3.04 kW of heat, and 26.8 W of cooling with a total efficiency of ~77% and fuel saving of 43.25%. The presented research is the contribution brought forward, as it heuristically highlights miscellaneous thermoelectricity studies/parameters of interests in a single manuscript, which further established that practical applications of thermoelectricity are possible and can be innovatively applied together with FC for efficient CCHP applications.
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Sun, Wei, Pengfei Wen, Sijie Zhu e Pengcheng Zhai. "Geometrical Optimization of Segmented Thermoelectric Generators (TEGs) Based on Neural Network and Multi-Objective Genetic Algorithm". Energies 17, n. 9 (27 aprile 2024): 2094. http://dx.doi.org/10.3390/en17092094.
Abstract (sommario):
In this study, a neural network and a multi-objective genetic algorithm were used to optimize the geometric parameters of segmented thermoelectric generators (TEGs) with trapezoidal legs, including the cold end width of thermoelectric (TE) legs (Wc), the ratios of cold-segmented length to the total lengths of the n- and p-legs (Sn,c and Sp,c), and the width ratios of the TE legs between the hot end and the cold end of the n- and p-legs (Kn and Kp). First, a neural network with high prediction accuracy was trained based on 5000 sets of parameters and the corresponding output power values of the TEGs obtained from finite element simulations. Then, based on the trained neural network, the multi-objective genetic algorithm was applied to optimize the geometric parameters of the segmented TEGs with the objectives of maximizing the output power (P) and minimizing the semiconductor volume (V). The optimal geometric parameters for different semiconductor volumes were obtained, and their variations were analyzed. The results indicated that the optimal Sn,c, Sp,c, Kn, and Kp remained almost unchanged when V increased from 52.8 to 216.2 mm3 for different semiconductor volumes. This work provides practical guidance for the design of segmented TEGs with trapezoidal legs.
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Jang, Hanhwi, Jong Bae Kim, Abbey Stanley, Suhyeon Lee, Yeongseon Kim, Sang Hyun Park e Min-Wook Oh. "Fabrication of Skutterudite-Based Tubular Thermoelectric Generator". Energies 13, n. 5 (2 marzo 2020): 1106. http://dx.doi.org/10.3390/en13051106.
Abstract (sommario):
The conversion efficiency of the thermoelectric generator (TEG) is adversely affected by the quality of thermal contact between the module and the heat source. TEGs with the planar substrate are not suitable for the curved heat sources. Several attempts have been made to tackle this issue by fabricating complex tubular-shaped TEGs; however, all efforts have been limited to low-temperature applications. Furthermore, the electrical contact resistance of the module is critical to achieving a high-power output. In this work, we developed the tubular TEG with significantly low specific contact resistance by optimizing the joining process. We show that the modified resistance welding (MRW) performed by spark plasma sintering (SPS) is an efficient joining method for the fabrication of the TE module, with high feasibility and scalability. This research seeks to suggest important design rules to consider when fabricating TEGs.
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Kawaguchi, Chiharu, Yae Hanesaka, Akira Yoshioka e Yukihiro Takahashi. "The In Vitro Analysis of the Coagulation Mechanism of Activated Factor VII Using Thrombelastogram". Thrombosis and Haemostasis 88, n. 11 (2002): 768–72. http://dx.doi.org/10.1055/s-0037-1613300.
Abstract (sommario):
SummaryWe investigated the effects of addition of recombinant activated coagulation factor VII (rFVIIa) to coagulation factor-deficient plasma and whole blood, using thrombelastograms (TEGs). The addition of rFVIIa to factor II-or X-deficient plasma did not correct hemostatic parameters, whereas it produced partial responses in factor V-, VIII-or IX-deficient plasma and good responses in factor VII-, XI-or XII-deficient plasma. Furthermore, the addition of rFVIIa and platelets (30-100 X 103/µl) to platelet-poor plasma produced marked corrections, producing TEGs similar to those of platelet-rich plasma. These results indicate that factors II and X are essential for the hemostatic effects of rFVIIa, and that factors V and VIII promote these effects. We believe that TEGs are, at present, one of the most useful tools for evaluating in vitro hemostatic effects of rFVIIa.
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Huang, Yen-Tsung, Thomas Hsu e David C. Christiani. "TEGS-CN: A Statistical Method for Pathway Analysis of Genome-wide Copy Number Profile". Cancer Informatics 13s4 (gennaio 2014): CIN.S13978. http://dx.doi.org/10.4137/cin.s13978.
Abstract (sommario):
The effects of copy number alterations make up a significant part of the tumor genome profile, but pathway analyses of these alterations are still not well established. We proposed a novel method to analyze multiple copy numbers of genes within a pathway, termed Test for the Effect of a Gene Set with Copy Number data (TEGS-CN). TEGS-CN was adapted from TEGS, a method that we previously developed for gene expression data using a variance component score test. With additional development, we extend the method to analyze DNA copy number data, accounting for different sizes and thus various numbers of copy number probes in genes. The test statistic follows a mixture of X 2 distributions that can be obtained using permutation with scaled X 2 approximation. We conducted simulation studies to evaluate the size and the power of TEGS-CN and to compare its performance with TEGS. We analyzed a genome-wide copy number data from 264 patients of non-small-cell lung cancer. With the Molecular Signatures Database (MSigDB) pathway database, the genome-wide copy number data can be classified into 1814 biological pathways or gene sets. We investigated associations of the copy number profile of the 1814 gene sets with pack-years of cigarette smoking. Our analysis revealed five pathways with significant P values after Bonferroni adjustment (<2.8 x 10-5), including the PTEN pathway (7.8 x 10-7), the gene set up-regulated under heat shock (3.6 x 10-6), the gene sets involved in the immune profile for rejection of kidney transplantation (9.2 x 10-6) and for transcriptional control of leukocytes (2.2 x 10-5), and the ganglioside biosynthesis pathway (2.7 x 10-5). In conclusion, we present a new method for pathway analyses of copy number data, and causal mechanisms of the five pathways require further study.
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Faraj, Jalal, Georges El Achkar, Bakri Abdulhay, El Hage Hicham, Rani Taher e Mahmoud Khaled. "New Concept of Power Generation from TEGs Using the Sun Irradiation and Oil Tanks – Thermal Modeling and Parametric Study". Defect and Diffusion Forum 428 (22 agosto 2023): 131–39. http://dx.doi.org/10.4028/p-8zrxu5.
Abstract (sommario):
In this manuscript, a new concept of power generation from thermoelectric generators TEGs using the sun irradiation and two oil tanks, one hot and one cold, is proposed. It consists of two oil tanks separated by a plate covering several TEGs in series. The oil tank at the bottom of the system constitutes a cold convection condition for the TEGs plate; on the other hand, the upper oil tank accounts for a hot convection condition since its upper surface is transparent and therefore subjected to the sun irradiation that will heat up the oil. To test the feasibility of this concept, an appropriate thermal modeling is developed and associated parametric analysis was carried out. It shows that powers up to 242 W can be generated with a system having a hot oil tank height of 0.2 m along with a width and length of 2 m each.
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Chung, Yi-Cheng, e Chun-I. Wu. "Enhancing Ocean Thermal Energy Conversion Performance: Optimized Thermoelectric Generator-Integrated Heat Exchangers with Longitudinal Vortex Generators". Energies 17, n. 2 (22 gennaio 2024): 526. http://dx.doi.org/10.3390/en17020526.
Abstract (sommario):
The effective utilization of renewable energy has become critical to technological advancement for the energetic transition from fossil fuels to clean and sustainable sources. Ocean Thermal Energy Conversion (OTEC) technology, which generates electricity by leveraging the temperature differential between surface and deep ocean waters, enables stable power generation around the clock. In this domain, the combination of thermoelectric generators (TEGs) and heat exchangers has exhibited immense potential for ameliorating the deficiencies of conventional OTEC. This study uses finite element numerical simulation of the COMSOL5.5 software to investigate the fluid dynamics characteristics of heat exchangers with flat fins and different types of longitudinal vortex generators (LVGs) under the same number of fins. This research encompasses heat exchangers with rectangular, triangular, and trapezoidal LVGs. Concurrently, the analysis examines how the vortices generated by the LVGs influence the thermoelectric performance of the TEGs. The results demonstrate that heat exchangers integrating flat fins and LVGs can enhance the power generation efficiency of TEGs. However, the pumping power required by the LVGs constrains the thermoelectric conversion efficiency. Compared to rectangular and triangular LVGs, trapezoidal LVGs achieve a superior balance between output and pumping power. Heat exchangers utilizing trapezoidal LVGs can attain the highest TEG thermoelectric conversion efficiency with a specific seawater flow velocity. Overall, these findings provide valuable reference information for applying TEGs and heat exchangers in OTEC design.
40
Wnuk, Sławomir, George Loumakis e Roberto Ramirez-Iniguez. "Use of a 2-layer thermoelectric generator structure for photovoltaics cells cooling and energy recovery". E3S Web of Conferences 239 (2021): 00003. http://dx.doi.org/10.1051/e3sconf/202123900003.
Abstract (sommario):
A 2-layer thermoelectric generator was tested as a solution to increase the output of a PV cell. A number of practical experiments were carried out on both single and two combined thermoelectric generator (TEG) configurations connected in series with photovoltaic (PV) cells and connected to a load independently from each other. Testing was performed using a class AAA solar simulator system Sol3A and under real outdoor weather conditions. The results show a reduction of the maximum cell temperature by 10.3 ° on average and at the same time an increase in the tested photovoltaics-thermo-generators (PV-TEGs) voltage output of the proposed hybrid systems by 28.56-30.54% compared to the plain PV cell. It was experimentally confirmed that the TEGs-PV structure performs better than the bare PV cell during decline of insolation utilising, in addition to the limited at this time solar energy, the heat accumulated by the multilayer structure components. Experiments showed that for the selected period of time (1600s) the energy output increased by 27.6% compared to a plain PV cell. For a constant level of artifical light (1000W/m2) the PV-TEG’s hybrid system showed an increase of energy yield of 3.1% compared to a plain PV system.
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Pintanel, Mª Teresa, Amaya Martínez-Gracia, Mª Pilar Galindo, Ángel A. Bayod-Rújula, Javier Uche, Juan A. Tejero e Alejandro del Amo. "Analysis of the Experimental Integration of Thermoelectric Generators in Photovoltaic–Thermal Hybrid Panels". Applied Sciences 11, n. 7 (24 marzo 2021): 2915. http://dx.doi.org/10.3390/app11072915.
Abstract (sommario):
Photovoltaic–thermal panels (PVT) have been widely studied in the last years and have proved to be a technically viable and profitable solution. This work analyses the integration of a set of thermoelectric generators (TEG) inside these panels in order to obtain additional power. The thermoelectric material takes advantage of the temperature gap between the hottest part of the system, the output flow from the collector, and the cold water feeding the solar system. An experimental test bench with a PVT having integrated TEGs and the same PVT in parallel without TEGs was mounted to compare both devices. The corresponding CFD simulation was also carried out to better understand the temperature map in the arrangement. Both experimental and computational results show that the manufacture of the panel with integrated TEGs should be carefully studied before becoming a commercial product. They also gave some guidelines for the improvement of the prototype in this integrated product.
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Schwab, Julian, Christopher Fritscher, Michael Filatov, Martin Kober, Frank Rinderknecht e Tjark Siefkes. "Experimental Analysis of the Long-Term Stability of Thermoelectric Generators under Thermal Cycling in Air and Argon Atmosphere". Energies 16, n. 10 (17 maggio 2023): 4145. http://dx.doi.org/10.3390/en16104145.
Abstract (sommario):
It is estimated that 72% of the worldwide primary energy consumption is lost as waste heat. Thermoelectric Generators (TEGs) are a possible solution to convert a part of this energy into electricity and heat for space heating. However, for their deployment a proven long-term operation is required. Therefore, this research investigates the long-term stability of TEGs on system level in air and argon atmosphere under thermal cycling up to 543 K. The layout of the examined test objects resembles a TEG in stack design. The results show that the maximal output power of the test object in air reaches a plateau at 57% of the initial power after 50 cycles caused by an increased electrical resistance of the system. Whereas the test object in argon atmosphere shows no significant degradation of electrical power or resistance. The findings represent a step towards the understanding of the long-term stability of TEGs and can be used as a guideline for design decisions.
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Williams, N. P., L. Roumen, G. McCauley e S. M. O’Shaughnessy. "Performance evaluation of thermoelectric generators under cyclic heating". Journal of Physics: Conference Series 2116, n. 1 (1 novembre 2021): 012087. http://dx.doi.org/10.1088/1742-6596/2116/1/012087.
Abstract (sommario):
Abstract The effect of thermal cycling on thermoelectric generator (TEG) performance is investigated for six nominally identical samples subjected to the same heating cycle profile. All TEGs experienced performance degradation, with maximum power outputs between 28 % and 49 % of pre-cycling values and a post-cycling decrease in the dimensionless figure of merit ZT of 21 % to 49 %. Sudden significant power reductions and subsequent internal resistance increases were observed for all samples, indicative of internal damage to the structure of the TEGs arising from material interface separation and micro-crack formation.
44
Jia, Xiaodong, Shifa Fan, Zhao Zhang e Hongbiao Wang. "Performance Assessment of Thermoelectric Generators with Application on Aerodynamic Heat Recovery". Micromachines 12, n. 11 (14 novembre 2021): 1399. http://dx.doi.org/10.3390/mi12111399.
Abstract (sommario):
Based on thermoelectric generators (TEGs), an aerodynamic heat energy recovery system for vehicle is proposed. A mathematical model describing the energy conversion law of the system is established, and the integrated calculation method which combined aerodynamic heating and thermoelectric (TE) conversion is given. Furthermore, the influences of the typical flight Mach number, flight altitudes and the length of TE legs on the energy conversion behavior of energy recovery systems are investigated. The performance of the energy recovery system is analyzed and evaluated. The results show that, the decrease of flight altitude and the increase of Mach number will obviously improve the performance of the heat energy recovery system with TEGs. The increase of leg length will increase the temperature of the hot end of TEGs and reduce the heat absorbed at the hot end. When the external load, Mach number and flight altitude is fixed, there exists an optimal length of legs corresponding to the maximum output power and maximum conversion efficiency of the system. The results will have significant positive impact on thermal protection and management of supersonic/hypersonic vehicles.
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Xie, Huadeng, Yingyao Zhang e Peng Gao. "Thermoelectric-Powered Sensors for Internet of Things". Micromachines 14, n. 1 (23 dicembre 2022): 31. http://dx.doi.org/10.3390/mi14010031.
Abstract (sommario):
The Internet of Things (IoT) combines various sensors and the internet to form an expanded network, realizing the interconnection between human beings and machines anytime and anywhere. Nevertheless, the problem of energy supply limits the large-scale implementation of the IoT. Fortunately, thermoelectric generators (TEGs), which can directly convert thermal gradients into electricity, have attracted extensive attention in the IoT field due to their unique benefits, such as small sizes, long maintenance cycles, high stability, and no noise. Therefore, it is vital to integrate the significantly advanced research on TEGs into IoT. In this review, we first outline the basic principle of the thermoelectricity effect and summarize the common preparation methods for thermoelectric functional parts in TEGs. Then, we elaborate on the application of TEG-powered sensors in the human body, including wearable and implantable medical electronic devices. This is followed by a discussion on the application of scene sensors for IoTs, for example, building energy management and airliners. Finally, we provide a further outlook on the current challenges and opportunities.
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Liu, Junpeng, Yajing Sun, Gang Chen e Pengcheng Zhai. "Performance Analysis of Variable Cross-Section TEGs under Constant Heat Flux Conditions". Energies 16, n. 11 (1 giugno 2023): 4473. http://dx.doi.org/10.3390/en16114473.
Abstract (sommario):
In this paper, five shapes of thermoelectric generator (TEG) models (cylindrical, barrel shaped, hourglass shaped, cup shaped, and inverse cup shaped) are built under the boundary conditions of heat flux at the hot end and convection at the cold end of the TEGs. Based on the numerical simulation results, the configuration of the variable cross-section can effectively boost the performance of TEGs. Remarkably, the hourglass-shaped TEG generated the maximum output power and efficiency, which were 69.62% and 70.96% higher than that of the conventional cylindrical TEG, respectively. The results indicate that the hourglass shape is beneficial to enlarge the temperature difference between the two ends of the TEG, which results in performance improvement. In addition, the effects of heat flux and convection on the performance of TEGs are explored and discussed. After choosing the appropriate boundary conditions, the relationships between the maximum output power and efficiency and the shape factor of the hourglass-shaped TEG are obtained according to the fitting results. Finally, some conclusions are drawn to provide guidance for TEG applications.
47
Raksha, E. V., A. A. Davydova, G. K. Volkova, O. N. Oskolkova, P. V. Sukhov, V. V. Gnatovskaja, V. A. Glazunova et al. "Triple graphite nitrate cointercalation compounds with acetic acid as precursors for thermally expanded graphite and carbon nanoparticles". Journal of Physics: Conference Series 2052, n. 1 (1 novembre 2021): 012035. http://dx.doi.org/10.1088/1742-6596/2052/1/012035.
Abstract (sommario):
Abstract Triple graphite nitrate cointercalation compounds (GNCCs) with acetic acid were synthesized, characterized by powder XRD and SEM methods, and used as a source of the thermally expanded graphite (TEG). Structural reorganization of graphite nitrate-acetate and triple GNCCs with acetic acid as a result of their exposition in air is discussed on the base of powder XRD data. Dispersions of carbon nanoparticles were prepared by liquid phase exfoliation of TEGs obtained from the GNCCs. It was demonstrated by TEM method that using of the studied TEGs as a source of carbon nanoparticles favours formation of few-layered graphene.
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Ragupathi, P., e Debabrata Barik. "Investigation on the Heat-to-Power Generation Efficiency of Thermoelectric Generators (TEGs) by Harvesting Waste Heat from a Combustion Engine for Energy Storage". International Journal of Energy Research 2023 (6 febbraio 2023): 1–13. http://dx.doi.org/10.1155/2023/3693308.
Abstract (sommario):
The present work explores a novel method of waste heat recovery (WHR) from the internal combustion (IC) engine and power generation using heat from hot exhaust gas (HEG) and thermoelectric generator (TEG). This system uses TEGs of aluminium oxide (Al2O3), bismuth telluride (Bi2Te3), lead telluride (PbTe3), and silicon germanium (SiGe) for the investigation of WHR and power generation. The experiments were conducted using a 5.9 kW diesel engine as a source of heat and a heat exchanger (HE) with fins. The parameters such as variation in temperature, rate of heat recovery, rate of power generation, and conversion efficiency of TEGs were analyzed by varying the load on the engine from 0% to 100% with steps of 25% and different zones of the heat exchanger, namely, zone 1, zone 2, zone 3, and zone 4. During the experiment, it was observed that zone 2 gives a high-temperature difference compared to zone 1, zone 3, and zone 4. TEG of bismuth telluride (Bi2Te3) increases the heat recovery rate overall compared to Al2O3, PbTe3, and SiGe throughout the load spectrum and operating conditions concerning different zones. The maximum power generation by TEGs of Al2O3, Bi2Te3, PbTe3, and SiGe was found to be 6.35 W, 7.18 W, 6.41 W, and 5.93 W at zone 2 while the engine was operated at 75% of load, respectively. Bi2Te3 gives the highest conversion efficiency compared to other TEGs irrespective of the working zones. The thermal energy-to-electrical energy conversion efficiency was maximum of about 7.8% given by the TEG of Bi2Te3 at zone 2 while the engine was operated at 75% of the load.
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Mat Noh, Nor Amelia Shafikah, Baljit Singh Bhathal Singh, Muhammad Fairuz Remeli e Amandeep Oberoi. "Internal Combustion Engine Exhaust Waste Heat Recovery Using Thermoelectric Generator Heat Exchanger". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 82, n. 2 (30 aprile 2021): 15–27. http://dx.doi.org/10.37934/arfmts.82.2.1527.
Abstract (sommario):
Heat engine converts chemical engine available in fuel to useful mechanical energy. One of the most famous heat engines is internal combustion (IC) engine. IC engine plays a pivotal role in transportation and other industrial applications. A lot of waste heat is rejected from a typical IC engine as the conversion efficiency of this type of engine is only about 35-40 %. The waste heat has the potential to be tapped and converted into useful energy. This can help to increase the performance of the IC engine system. This work focused on the conversion of the waste heat energy of the IC engine into electricity by using thermoelectric generator (TEG). The aim of the project was to demonstrate the applicability of TEG to convert waste heat from exhaust to useful electrical energy. Two TEGs were individually tested to attain the electrical characterization and also tested on series and parallel connections. The study showed that the series connection of TEGs has improved and increased voltage generation but parallel connection is more reliable. The system proved that the waste heat recovery using TEGs has tremendous application in IC engine for better and higher efficient engine performance.
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Xiao, Di, Peng Sun, Jianlin Wu, Yin Zhang, Jiehua Wu, Guoqiang Liu, Haoyang Hu et al. "Thermoelectric Generator Design and Characterization for Industrial Pipe Waste Heat Recovery". Processes 11, n. 6 (3 giugno 2023): 1714. http://dx.doi.org/10.3390/pr11061714.
Abstract (sommario):
Thermoelectric technology is an effective strategy to convert low–grade waste heat to electrical energy directly. Thermoelectric generators (TEGs) have been extensively studied in various waste heat scenarios, such as vehicle exhaust, metal casting processes and more. However, industrial pipelines also possess high levels of heat and wide distribution, yet there is limited research on TEGs for use in these pipes. The challenge in designing a TEG lies in the heat collector, which is complicated by the distinct structural differences between pipe and plate–shaped TEMs. Ultimately, we propose an arch bridge–shaped heat collector for the pipe to recover wasted thermal energy. The effects of some key factors, such as topology of TEMs, heat source temperature, cooling water temperature and velocity, on the generating performance are studied. The TEG achieved a temperature difference of 65.98 °C across the two ends of the TEM, resulting in an output power of 17.89 W at an open–circuit voltage of 133.35 V. This provides evidence that the designed heat collector is a feasible solution for recovering waste heat from pipes using TEG technology. This work provides reliable experimental data and efficient design for the application of TEGs in industrial pipes.