Thermoelectric Generator Prototype Research Articles

Add-On Energy Harvesting of Diesel Exhaust Muffler Using Thermoelectric Generator

Trends Light fossil fuel vehicles are now turning to electricity. The electric vehicle transition begins with a hybrid car. The Hybrid vehicle uses an internal combustion engine as a generator. Controller systems, driving safety and entertain light vehicles are growing so that they consume a lot of electricity, Safe devices and driving lifestyle support. An additional battery charging system for a hybrid car now is being developed by the automotive manufacturer at least the system can increase the fulfilment of electricity consumption needs.The charging system can utilize waste energy vehicle itself or even from outside the vehicle system. In this research, the author wants to explore the thermal energy harvesting system in the remaining exhaust gases. The concept of this research is to develop a Thermoelectric Generator (TEG) as a power producer. The heat source uses a 140kW diesel engine with a heat potential of 523K at stationary conditions, and an exhaust velocity of 1407.05 m / s. This study demonstrates the potential prototype TEG then compared Ansys simulation and manual calculations as the first step for further research. The results obtained, the Exhaust TEG can produce a voltage of 2.1 Volt at 30 seconds of data collection. The cooling system on the TEG exhaust from the HVAC cooler with a temperature of 289K and a Velocity of 0.8 can produce a significant temperature difference.Keywords: Diesel Engine, Thermoelectric, Exhaust TEG system, Electricity.

A thermoelectric generation system using waste heat recovery from petrochemical pipeline to power wireless sensor

ABSTRACT Wireless monitoring sensor gradually replaces wired equipment for data support in petrochemical industry production. This paper presented a design of a thermoelectric generator (TEG) system-based petrochemical pipeline waste heat recovery for wireless sensor. The TEG is assembled using an easy-to-modify structure that can be mechanically adjusted to different pipelines. Besides, we designed a new zero-power, micro-vibration, and easy-to-install heat sink for TEG applied in high-temperature petrochemical pipelines. The proposed TEG prototype has been fabricated and tested. The experimental results show that the system proposed in this work can supply enough energy to sustain the operation of a wireless sensor node that measures petrochemical fluid temperature and pressure for precision industrial production applications. The minimum output power is 24.7 mW at the hot side of thermoelectric generation (TEG) temperature of 100◦C −190◦C. This work presents a promising, cost-effective new approach to the conversion of waste heat into electricity for self-powered sensor networks.

Analyzing the Performance of Thermoelectric Generators with Inhomogeneous Legs: Coupled Material–Device Modelling for Mg2X-Based TEG Prototypes

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.

Enhanced Thermoelectric Performance of Rare-Earth-Free n-Type Oxide Perovskite Composite with Graphene Analogous 2D MXene.

Here, the first experimental demonstration on the effect of incorporating new generation 2D material, MXene, on the thermoelectric performance of rare-earth-free oxide perovskite is reported. The charge localization phenomenon is predominant in the electron transport of doped SrTiO3 perovskites, which deters from achieving a higher thermoelectric power factor in these oxides. In this work, it is shown that incorporating Ti3 C2 Tx MXene in a matrix of SrTi0.85 Nb0.15 O3 (STN) facilitates the delocalization of electrons resulting in better than single-crystal-like electron mobility in polycrystalline composites. A 1851% increase in electrical conductivity and a 1000% enhancement in power factor are attained. Besides, anharmonicity caused by MXene in the STN matrix has led to enhanced Umklapp scattering giving rise to lower lattice thermal conductivity. Hence, 700% ZT enhancement is achieved in this composite. Further, a prototype of thermoelectric generator (TEG) using only n-type STN + MXene is fabricated and a power output of 38mW is obtained, which is higher than the reported values for oxide TEG.

Highly Electrical Conductive PEDOT:PSS/SWCNT Flexible Thermoelectric Films Fabricated by a High-Velocity Non-solvent Turbulent Secondary Doping Approach.

Materials based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) can be potentially employed as flexible thermoelectric generators (TEGs) to capture waste heat and generate electrical energy. Among various methods, secondary doping is an effective way to modulate its thermoelectric (TE) performance. Different from conventional measures such as dropping, soaking, and steam fumigation, strong shear is integrated with the doping process and termed high-velocity non-solvent turbulent secondary doping (HNTD). We systematically investigate the transformation of PEDOT:PSS during this procedure and the formation mechanism of its highly conductive pathway. It is illustrated that PEDOT:PSS experiences PSS swelling, the phase separation of PEDOT from PSS, the removal of isolated PSS, and the evolution of PEDOT to a linear conformation. These evolutions contribute to the substantial elevation of electrical conductivity (σ). Furthermore, by employing continuous single-walled carbon nanotube (SWCNT) networks as structural units, highly conductive flexible PEDOT:PSS/SWCNT TE thin films could be prepared without sacrificing the Seebeck coefficient (S). Additionally, the effect of HNTD and direct addition method on TE properties of composite films is also compared. Finally, the PEDOT:PSS composite film with 40 wt % SWCNTs by the HNTD method exhibits the maximized power factor (PF) of 501.31 ± 19.23 μW m-1 K-2 with σ of 4717.8 ± 41.51 S cm-1 and S of 32.6 ± 0.13 μV K-1 at room temperature. It is worth mentioning that the σ value 4717.8 ± 41.51 S cm-1 is the highest among the composites based on commercial carbon fillers and organic semiconductors. Finally, a 6-leg TEGs prototype is assembled and illustrates an output power of 4.416 μW under a temperature difference (ΔT) of 58 K. It is thought that such a strategy may provide some guidelines for manufacturing PEDOT:PSS-based functional materials.

Compositing Nanostructured Polyaniline with Single-Walled Carbon Nanotubes for High Thermoelectric Performance

In the face of the growing energy crisis and demand on environmental protection, organic thermoelectric (TE) materials have been coming under the spotlight from global researchers as a potential countermeasure. However, there have been few studies on the relationship between the morphology of conductive polymers (CPs) and their TE performance. In this work, nanostructured polyaniline (PANI) was synthesized by interfacial polymerization with the addition of organic solvents of different polarities, including cyclohexane (CYH), carbon tetrachloride (CCl4), toluene (MB), dichloromethane (DCM), and dimethyl sulfoxide (DMSO). Physical mixing PANI with single-walled carbon nanotubes (SWCNTs) affords PANI/SWCNT composites. The composite of PANI nanobelts and 10 wt% SWCNTs achieves a power factor (PF) of 5.13 ± 0.56 μW m-1 K-2 at room temperature (RT). Spherical PANI doped with 50 wt% SWCNTs followed by pressing affords maximal room temperature PF value of 178.10 ± 3.77 μW m-1 K-2. A prototype TE generator (TEG) constructed with seven pairs of legs of as-prepared PANI/SWCNT composites and their n-type counterparts generates voltage of 10.27 ± 0.15 mV and output power of 36.65 ± 1.18 nW at temperature difference of about 50°C. This work illustrates that well-regulated PANI nanostructure could significantly affect the TE properties of PANI/SWCNT composites, which are promising in future preparation of high-performance polymer-based composites regarding the fabrication of TE devices suitable for harnessing low-grade waste heat.

Performance comparison of a thermoelectric generator applied in conventional vehicles and extended-range electric vehicles

Hybrid electric vehicles constitute an important stage in the global paradigm shift from conventional fossil-fuelled vehicles to electric vehicles. Thermoelectric generators, as a promising waste heat recovery system, also need to transfer their implementation from conventional vehicles to hybrid electric vehicles. In this paper, a performance comparison of the same thermoelectric generator prototype applied in a conventional vehicle and an extended-range electric vehicle is conducted through both simulation and experimental methods. The effects of power management strategies, driving cycles and auxiliary power on the fuel economy improvement due to thermoelectric generators are analysed. The results indicate that in an urban driving cycle thermoelectric generator applied in the extended-range electric vehicle using the power follower control strategy shows better fuel economy than with integration into the conventional vehicle. However, in a highway driving cycle, the fuel saving effect of the thermoelectric generator integrated in the conventional vehicle is better. It is also shown that the power follower control strategy is more suitable than the thermostat control strategy for the integration of thermoelectric generators in extended-range electric vehicles. It is observed that driving cycle and auxiliary power only influence and restrict the fuel economy improvement of thermoelectric generators applied in conventional vehicles and have little effect on their application to extended-range electric vehicles.

Experiments on Waste Heat Thermoelectric Generation for Passenger Vehicles.

In order to utilize waste heat from passenger vehicles by a thermoelectric generator (TEG), a lab-scale TEG with a sufficient low-pressure drop was designed and tested. The waste heat from a 2.0 L petrol engine was simulated by using an air-circulation channel with an adjustable electric heater and a speed control motor. The TEG consisted of an integrated molding designed aluminum-finned heat collector, twenty thermoelectric modules, and a set of water-cooled heat sinks. Experiments were conducted in terms of power load feature, pressure drop, heat collection efficiency, thermoelectric efficiency and overall efficiency. It was found that the hot-end temperature was much lower (46.9%) than the flue gas temperature because the trade-off between fin area and pressure drop had to be considered. The obtained maximum electric power was 36.4 W, and the corresponding pressure drop was 36 Pa. The corresponding heat collection efficiency was 46.5%, and the thermoelectric efficiency was 2.88%, which agreed well with the theoretical prediction of 3.38%. As a result, an overall efficiency of 1.21% was reached. The present work firstly demonstrated a waste-heat-recovering TEG prototype with a balanced overall efficiency of over 1%, and a pressure drop of less than 50 Pa. On the other hand, the maximum electric power was difficult to fully extract. The charging power to a battery with a maximum power point tracking direct current–direct current converter was experimentally verified to work at a much higher conversion efficiency (15.3% higher) than regular converters.

Analytical design model for waste heat thermoelectric generator and experimental verification

Low conversion efficiency of power systems and carbon emission induced climate crisis boost extensive investigations on waste heat utilization, particularly studies of converting waste heat into high-grade electric energy. Thermoelectric generator (TEG) is such a potential solution to abovementioned technical demand. An analytical design model for waste heat TEG, interlinking the underlying three different levels (material, device, and system), is not reported yet though a large number of previous researches intensively studied various important aspects of waste heat TEG with theoretical, numerical and experimental methods. The analytical design model, firstly developed in this work, constructs a straightforward but thoughtful bridge to interlink material, device, and system levels of waste heat TEG, providing multilevel-coupled heat collection surface area, expected electric power outcome, and resulting pressure drop. A high performance customized waste heat TEG can be readily obtained using the present analytical design model with necessary boundary inputs. The effectiveness and accuracy are verified through experimental data. A waste heat TEG prototype with 24 TE modules, exactly machined and assembled according to the developed analytical design model, shows superior performance when compared to previous TEGs. The abovementioned TEG generates an electric power of 96.6 W with a pressure drop of 375 Pa under the exhaust gas temperature of 648 K. Comprehensive discussions are presented to indicate limitations and applications of the developed analytical design model.

Three-zone numerical modeling method for predicting system-level waste heat recovery performance of thermoelectric generator with various electrical array configurations

In this study, an experimentally validated numerical model is formulated to accurately predict the energy harvesting performance of a thermoelectric generator (TEG) by reflecting the underlying physics of the thermoelectric energy conversion phenomena. The most advantageous feature of the modeling method employed herein is its high reliability because the system-level performance is predicted based on module-level power generation characteristics. A further benefit that the proposed physics-based model affords is that the effect of electrical array configurations (i.e., the particular manner by which the thermoelectric modules (TEMs) are electrically connected) on the waste heat recovery performance of the TEG can be accurately predicted. For this purpose, a three-zone modeling method, wherein each TEM is modeled into heat sink, heat generation, and heat conduction zones, is proposed. Moreover, user-defined functions are embedded into the numerical model to correlate the temperature fields obtained from the transport of momentum and energy with the Seebeck effect and Joule heating that appear as the thermoelectric output power and heat sink/heat generation near the TEM surface. The accuracy and reliability of the numerical model are validated by the experimental results of temperature and output power using a TEG prototype whose configurations and dimensions are identical to those of the proposed numerical model. Further comparisons between the numerical results obtained using eight different electrical array configurations and the corresponding experimental results ensure the robustness of the modeling method and numerical model formulated in this study. Finally, two correlations are derived as a function of the number of electrical array branches to predict the output voltage and current of a TEG whose branches consist of an identical number of TEMs for minimizing unexpected power losses.

Paper-based thermoelectric generator based on multi-walled carbon nanotube/carboxylated nanocellulose

Cellulose is the most abundant polymer material in nature. After being produced on the nanometer scale, it is widely used in research on flexible energy storage equipment and power supply equipment. Therefore, this study has prepared a nanocomposite thermoelectric material based on multi-walled carbon nanotube (MWCNT) and carboxylated nanocellulose fiber (C-CNF) and obtained a free-standing paper-based thermoelectric generator (TEG) through a simple printing method. The equipment exhibits excellent mechanical flexibility. At the same time, the thermal conductivity is significantly reduced under the dual effects of paper and C-CNF (is reduced to 0.02–0.09 W/mK). The TEG prototype has four P-shaped feet. Under a temperature gradient of 70 K, the open circuit voltage is 3.3 mV, and the output power is up to 3.7 nW. This work not only confirms the improvement of MWCNT thermoelectric performance by C-CNF but also provides a new strategy for the preparation of low-cost and environmentally friendly thermoelectric generators.

Testing of proposed design of stove-powered thermoelectric generator using natural and forced air cooling

This paper presents the prototype design, implementation and testing of a thermoelectric generator unusually applied to the fireplace stoves. The tested low-cost thermoelectric generator can be used as an alternative low source of electricity in areas with limited access to public electricity networks. Moreover, inclusion of a thermoelectric generator in the fireplace stove structure is novelty and interesting accessory in offer for customer. This study focuses on testing and determining the output values of voltage and current of the initial design using the natural and forces air cooling. The results are obtained by developed measuring device for that testing. The low-cost thermoelectric generator provided the power of 1.5 W at temperature difference 94°C using forced air cooling. Thus a thermoelectric generator prototype design is suitable for powering LED lighting and fans or recharging a mobile phone battery.

Flexible cellulose nanofiber/Bi2Te3 composite film for wearable thermoelectric devices

Cellulose nanofiber (CNF) is obtained from cellulose resources (e.g., natural cellulose, bacterial cellulose, etc.) and is considered to be a low-cost, green and inexhaustible material. The impressive optical, mechanical, and thermal properties of this material have aroused great interest in fabricating of flexible electronic devices based on CNF. Hereby, the CNF/Bi2Te3 thermoelectric composite films are fabricated using a facile vacuum filtration method. Subsequently, n-type and p-type films composed of this composite materials are used as legs to assemble thermoelectric generator (TEG) prototype. Besides, these composite films exhibit excellent mechanical flexibility and the electrical conductivity of the CNF/Bi2Te3 film only decreases by 8% after 1000 bending cycles. And the contact angle of the polytetrafluoroethylene (PTFE) solution and alkylketene dimmer (AKD) emulsion co-treated film is as high as 150.7°, which has superhydrophobic properties. The TEG prototype consists of five p-n legs. At a temperature gradient of 60 K, the output voltage of the TEG prototype is 22.34 mV and the output power is 561 nW. This work not only proves the great potential of CNF application in flexible thermoelectric (TE) materials, but also promotes robust development of cellulose-based electronics.

Experimental study of a thin water-film evaporative cooling system to enhance the energy conversion efficiency of a thermoelectric device

In the study, a new method to enhance the performance of a thermoelectric generator (TEG) device by utilizing the water-film evaporative cooling is proposed. An experimental device was constructed by incorporating a water-film cooling pond with a commercially available TEG. Experiments were performed to investigate the effects of the main operating conditions (ambient temperature Tamb was 25 °C), TEG hot-side temperature (TH = 50–100 °C), ambient relative humidity (RH = 15–90%), and water-film thickness (twater = 1–9 mm) on the TEG output performance. Additionally, the output performance of TEG under different cooling methods was compared. A TEG prototype device was constructed to generate electricity/steam using seawater evaporation cooling without external electrical energy. The results indicated that TEG hot-side temperature and water-film thickness significantly affected output performance. However, the ambient relative humidity did not considerably affect TEG output performance. Given TEG hot-side temperature TH = 100 °C, ambient relative humidity RH = 15%, the TEG prototype device-generated open-circuit voltage of Uopen = 1.55 V, maximum output power of Pmax = 290.32 mW, and a steam generation rate of 9.82 mg/s. The results showed that evaporative cooling is an innovative method to improve the performance of TEG.

Utilization of Waste Combustion Heat as an Alternative Renewable Electric Energy Source Based on Thermoelectric Generator

Thermoelectric generator is one alternative energy source that is using a temperature difference system to produce electrical energy. This research study aims to utilize combustion heat waste using a thermoelectric generator as a source of renewable electricity. This research method uses the experimental method. The thermoelectric system was made using seven thermoelectric modules TEC1 - 12706 arranged in series by varying the combustion media in the form of Rice husk, Sengon sawdust (Albizia chinensis) and Teak sawdust (Tectona grandis). The test is done by measuring the output voltage, the temperature of the cold side and the hot side which are then analyzed to get the output power and generator efficiency. From the trial results it was found that the greater of the temperature difference, then the output voltage, output power and generator efficiency increase. Output voltage, output power and maximum efficiency of testing prototype thermoelectric generator that generated were 4.64 V, W 20.38 and 16.46 % with fuel Teak sawdust in the tenth minute when the temperature difference of 76.17 0C.©2019 JNSMR UIN Walisongo. All rights reserved.

Heat Transfer Characteristics of Heat Exchangers for Waste Heat Recovery from a Billet Casting Process

The application of the thermoelectric generator (TEG) system to various industrial facilities has been explored to reduce greenhouse gas emissions and improve the efficiency of such industrial facilities. In this study, numerical analysis was conducted according to the types and geometry of heat exchangers and manufacture process conditions to recover waste heat from a billet casting process using the TEG system. The total heat absorption increased by up to 10.0% depending on the geometry of the heat exchanger. Under natural convection conditions, the total heat absorption increased by up to 45.5%. As the minimum temperature increased, the effective area increased by five times. When a copper heat exchanger of direct conduction type was used, the difference between the maximum and minimum temperatures was significantly reduced compared to when a stainless steel heat exchanger was used. This confirmed that the copper heat exchanger is more favorable for securing a uniform heat exchanger temperature. A prototype TEG system, including a thermosyphon heat exchanger, was installed and a maximum power of 8.0 W and power density of 740 W/m2 was achieved at a hot side temperature of 130 °C. The results suggest the possibility of recovering waste heat from billet casting processes.

Thermoelectric Generator for Utilizing Cold Energy of Cryogen Liquids

In this paper, the results of experimental studies of a prototype cryogenic thermoelectric generator (TEG) using transit heat flows in a liquefied natural gas (LNG) evaporator are considered. The main objective was to develop a TEG with low capital cost, integrated directly into an LNG vaporizer, capable of generating electricity at a reasonable levelized cost (LCOE). A demonstration prototype of TEG was created with a power output of 800 W. The prototype used liquid nitrogen (LN2) instead of LNG as the working fluid. Achieved technical parameters of TEG provide the LCOE decrease to a level of ≈ 0.015 $/kWh. Such results are achieved using standard components (thermoelectric modules, heat exchangers, etc.) thanks to the optimization of the TEG design.

Harvesting thermoelectric energy from railway track

This study aims to develop a prototype for harvesting thermoelectric energy from railway track. By capturing the existing thermal energy in railway tracks, this technology helps power rail-side sensors in off-grid and remote areas without depleting natural resources. In low latitudes such as southern China, the temperature of railway tracks can reach 57 °C due to solar radiation. However, at a relatively shallow depth (200 mm), the substratum below the track foundation (e.g., soils) has a lower temperature (i.e., 15 °C–26 °C). This temperature difference can be used to generate electricity through a thermoelectric generator (TEG). The proposed approach captures thermal energy from the railway track and transfers the energy to the TEG prototype beneath the bottom of rails. Evaluation of the prototype is conducted by finite volume analysis, field test, and laboratory experiment. The results indicate that the TEG prototype can produce 5.8 mW–316.8 mW of power across a resistant load at thermal gradient from 8 °C to 29.2 °C. A DC-DC buck-booster circuit with lithium battery management is developed to charge the batteries by the harvested thermal energy. The system operates at a low startup voltage of 0.9 V and its conversion efficiency is larger than 60%.

Atomic Layer Tailoring Titanium Carbide MXene To Tune Transport and Polarization for Utilization of Electromagnetic Energy beyond Solar and Chemical Energy.

The utilization of electromagnetic (EM) energy neither is affected by the weather nor produces harmful substances. How to utilize and convert EM energy is of practical concern. Herein, delaminated titanium carbide (D-Ti3C2Tx) MXene nanosheet (NS) was successfully fabricated by the modified Gogotsi's method. The choice of atomic layer processing allows tailoring of layer distance of Ti3C2Tx so as to improve polarization. High-performance EM wave absorption of D-Ti3C2Tx MXene NS composites was obtained, and their comprehensive performance is the best of all Ti3C2Tx-based composites. Due to the competition between conduction loss and polarization loss, the higher the concentration of D-Ti3C2Tx in composites, the more the conversion of EM energy to thermal energy will be. Based on the mechanism, a prototype of thermoelectric generator is designed, which can convert the EM energy into power energy effectively. This thermoelectric generator will be the energy source for low power electric devices. Our finding will provide new ideas for the utilization of EM energy.

Fabrication of Transparent Paper-Based Flexible Thermoelectric Generator for Wearable Energy Harvester Using Modified Distributor Printing Technology.

Paper-based substrates have been increasingly attractive in flexible electronics technology as flexible support substrates due to their advantages of availability, environmental friendliness (as disposable, degradable, and renewable materials), and foldability. Hereby, a facile method for installation of p-type and n-type semiconductor legs in the thickness direction of a paper substrate was established. A transparent paper-based thermoelectric generator prototype by impregnating the paper with resin was then fabricated. The resulting transparent paper-based thermoelectric generator with 10 thermocouples showed excellent mechanical flexibility. The generator maintained a maximum voltage and an output power of ∼8.3 mV and ∼10 nW, respectively, at a temperature difference of 35 K after 1000 bending cycles. This work offers a promising strategy for the development of paper-based thermoelectric generators that are adaptable to a wide variety of complex curved surface heat source. Therefore, the heat recovery efficiency in both human and natural environments can be greatly improved.