Thermoelectric Generator System Research Articles

Comprehensive research on a high performance solar and radiative cooling driving thermoelectric generator system with concentration for passive power generation

Comprehensive research on a high performance solar and radiative cooling driving thermoelectric generator system with concentration for passive power generation

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.

Thermal and Electrical Performances of Thermoelectric Generator System for Different Internal Fin Structures

In the present study, the thermal and electrical performances of automotive waste heat recovery thermoelectric generator system are investigated for different internal fin structures in hot heat exchanger. A coupled numerical model integrated with heat transfer and thermoelectric effects is developed to simulate the Multiphysics behavior of thermoelectric generator system. The coupled numerical model is validated with experimental results for both thermal and electrical performances within maximum error of ± 8%. The temperature difference, pressure drop, power, conversion efficiency, exergy efficiency, and net efficiency of thermoelectric generator system are compared for hot heat exchanger without internal fin structure and that with 12 different internal fin structures. The 12 different internal fin structures comprise of straight fins, perpendicular fins, fishbone fins, triangular guide fins, and combination of fins. The results reveal that, an Internal structure11 depicts superior thermal and electrical performances of thermoelectric generator system among all internal fin structures. Despite of higher pressure drop of 0.04571 bar, the Internal structure11 shows superior power, conversion efficiency, exergy efficiency, and net efficiency of 70.79 W, 7.76%, 14.10%, and 0.996%, respectively. The hot heat exchanger with Internal structure11 is proposed as the best configuration for the optimum performance of thermoelectric generator system.

A multi-objective optimization in system level for thermoelectric generation system

For designing thermoelectric generation systems in practice, achieving the ideal goal of maximizing output power, maximizing system efficiency, and minimizing system investment are important. However, assumptions about the input heat and some coefficients considered by existing studies are usually ideal. The optimization of thermoelectric generator (TEG) systems by existing studies is usually for output power and conversion efficiency. In addition, existing studies are more focused on the optimization of TEG geometry rather than that of system parameters. The comprehensive multi-objective optimization of the overall system is lacking, as well as the comprehensive study of effects of system parameters on system performance. To help with the design of TEG system in real applications, this study firstly proposes a transient model for TEG system. The inputs are no longer unlimited heat source, instead, the amplitude, frequency and heat transfer coefficient are three system parameters considered. The model is then used to explore effects of three system parameters on output power, conversion efficiency and system investment, and is used to have a multi-objective optimization for better system design. With the help of this study, the investment of the system can be lowered by 30%–50%, while only lose output power and efficiency within 1%.

Experimental and parametric analysis of exhaust heat exchanger used in thermoelectric generator

A thermoelectric generator system consists of an exhaust heat exchanger, a thermoelectric module, and water heat exchanger. Perfect heat exchangers recover as much heat energy as possible from engine exhaust with an acceptable pressure drop. The capacity and efficiency of the heat exchanger depend on its shape, type, and material of the heat exchanger. The main objective of this research was to perform a parametric analysis of the test section of the exhaust heat exchanger by using simulation tools. The simulation results were validated with the experimental results to ensure the performance of the simulation model. The performance of the test section was measured in relation to geometry, pressure drop, temperature distribution, fluid velocity, and temperature uniformity coefficient. The test section of 60 mm × 60 mm × 180 mm (F-type) shows a higher surface temperature with an allowable pressure drop than the other types of test section without inserts. The inserts played a vital role in enhancing the surface temperature distribution and uniformity coefficient. The cone type (G-type), cone-cylinder type (H-type), and cone-cylinder-cone type (I-type) inserts were used to improve the performance of the F-type test section. The G-type and H-type test sections of the exhaust heat exchanger have a high surface temperature, high-temperature uniformity, and allowable pressure drop.

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.

Experimental Study on the Working Efficiency and Exergy Efficiency of the Vehicle-Mounted Thermoelectric Generator for Cold Chain Logistics Transportation Vehicle

This paper investigates a vehicle-mounted thermoelectric generator system working efficiency and exergy efficiency in a cold chain logistics transport vehicle (CLVTEG). The study examines the impact of factors such as load resistance, temperature difference, and copper foam on the performance of CLVTEG. Results demonstrate that adding copper foam significantly improves the output power of CLVTEG, with 40 PPI copper foam showing a 1.8 times increase compared to no copper foam. Additionally, copper foam enhances working and exergy efficiency, with 10 PPI copper foam achieving the best overall efficiency. The study also explores the effect of temperature difference on CLVTEGs efficiency, observing an initial increase followed by a decrease. Overall, this research underscores the importance of considering work and exergy efficiency when evaluating thermoelectric generators. Adding copper foam in the CLVTEG central area enhances heat transfer, resulting in improved efficiency. These findings offer valuable insights for optimizing the design and operation of thermoelectric generators in cold chain logistics transport vehicles.

Taguchi optimization and analysis of variance for thermoelectric generators with forced convection air cooling

In recent years, humanity has experienced the effects of using unsustainable energy sources that pollute the environment while being inefficient. Most of the primary energy input used in energy conversion processes is lost in the form of heat. Thermoelectric generators (TEGs) have the potential to recover some of this wasted heat; however, their low energy conversion efficiency needs to be addressed. Previous literature has shown effective optimization of thermoelectric generation systems through statistical tools such as the Taguchi method that optimized all the parameters that affect the outcome of the system. To this date, no research has considered wind speed for convection heat transfer as one of the optimizable parameters. This study aims to optimize the operating conditions of commercially available TEGs that are cooled by forced convection simulating naturally occurring wind speeds and operate under low-quality waste heat temperatures to improve the TEG performance further. Two commercially available TEGs are optimized via the Taguchi method. The Taguchi method is implemented with three parameters and three levels, making an L9 orthogonal array. The objective function is the maximum output power. The optimized parameters are the hot side temperature, the heat sink size, and the wind airspeed. Analysis of variance (ANOVA) is used alongside the Taguchi orthogonal array for the statistical analysis of the results. The optimization results show that the hot side temperature is the most influential parameter to the output power. In addition, the change in the heat sink size also significantly influences the output power, whereas the impact of the wind speed is not as significant. In addition, interaction analysis between the parameters is performed. The Taguchi method yields satisfactory optimization results. The optimized system yields 0.65 W of power at 140 °C hot side temperature, Model K402 heat sink, and 3.7 m·s−1 wind speed. The influence of the air velocity of 1.73% is minimal on the output power compared to the hot side temperature, with a level of influence of 75.67% and a heat sink size of 22.43% for the shorter module. The results also show that the TEG with a smaller TE leg height yields the best output power at low load resistance ranging from 0.2 Ω to 2 Ω, as the TEG with a taller TE leg renders better performance at higher load resistance ranging from 3 Ω to 16 Ω at the optimal conditions. The results show that the hot side temperature remains the most important parameter in the optimization process. Furthermore, convection cooling from naturally occurring winds has a minimal but positive effect on the output of the presented TEG system.

Development of a Hybrid Solar and Waste Heat Thermal Energy Harvesting System

This research aims to develop a Hybrid Solar and Waste Heat Thermal Energy Harvesting System that integrates Thermoelectric Generator (TEG) with a solar PV system. The main focus is given to the development of the hybrid solar and waste heat released from the solar panel by using the TEG system. This hybrid system consists of photovoltaic (PV) cells to absorb the solar energy and the TEG attached to the back of the panel to absorb heat waste and convert it into usable electricity. The PV cell and the TEG are integrated with each other in order to obtain maximum energy and increased system efficiency. The experimental results show that the maximum output voltage produced from the solar PV is 20.37V and the maximum output current generated is 203.72mA. The maximum output voltage obtained from the TEG is 18.92V and the maximum current produced is 189.265mA. This experimental result shows that the maximum voltage and current produced from solar and waste thermal heat from PV panels can be used to charge and to power up portable electronic devices. More efficiency is accomplished by combining the TEG to absorb waste heat loss from the PV cell, thus improving the performance of the PV panel system.

Recent development in structural designs and thermal enhancement technologies of thermoelectric generator with different types of heat sources: A review

The thermoelectric generator (TEG) as a noise-free, pollution-free and environmentally friendly energy-conversion device has been intensively investigated in the last few decades. For different TEG applications, the characteristics of their heat sources determine the structural designs of the TEG systems. In this work, we categorized TEG heat sources into three types: body heat, natural sources of heat energy, and industrial waste heat. The up-to-date three maim structural designs of wearable TEGs including film TEG, micro-bulk TEG, and yarn TEG were reviewed. For TEG using natural heat sources, the major structural designs of TEG using solar energy, geothermal energy, and ambient heat energy were summarized. In terms of TEG using industrial waste heat, the structures of TEG systems applied in automotive, household stoves, and factories were concluded. Meanwhile, key thermal enhancement technologies including different heat exchangers, heat pipes, and phase change material (PCM) to improve the performance of these TEG systems, as well as challenges of each TEG system were also concluded. This review is expected to provide inspiration for the structural designs of TEG systems with different types of heat sources and to offer potential performance enhancement technologies for engineers and researchers in this field.

Comparative Assessment of sCO2 Cycles, Optimal ORC, and Thermoelectric Generators for Exhaust Waste Heat Recovery Applications from Heavy-Duty Diesel Engines

This study aimed to investigate the potential of supercritical carbon dioxide (sCO2), organic Rankine cycle (ORC), and thermoelectric generator (TEG) systems for application in automotive exhaust waste heat recovery (WHR) applications. More specifically, this paper focuses on heavy-duty diesel engines applications such as marine, trucks, and locomotives. The results of the simulations show that sCO2 systems are capable of recovering the highest amount of power from exhaust gases, followed by ORC systems. The sCO2 system recovered 19.5 kW at the point of maximum brake power and 10.1 kW at the point of maximum torque. Similarly, the ORC system recovered 14.7 kW at the point of maximum brake power and 7.9 kW at the point of maximum torque. Furthermore, at a point of low power and torque, the sCO2 system recovered 4.2 kW of power and the ORC system recovered 3.3 kW. The TEG system produced significantly less power (533 W at maximum brake power, 126 W at maximum torque, and 7 W at low power and torque) at all three points of interest due to the low system efficiency in comparison to sCO2 and ORC systems. From the results, it can be concluded that sCO2 and ORC systems have the biggest potential impact in exhaust WHR applications provided the availability of heat and that their level of complexity does not become prohibitive.

The Influence of Peltier Effect on the Exergy of Thermoelectric Cooler–Thermoelectric Generator System and Performance Improvement of System

Thermoelectric modules (TEMs) have great potential in energy conversion. There is research about performance improvements of thermoelectric generator (TEG) and thermoelectric coolers (TECs). However, TEMs are always studied separately, and no research focuses on the influence of the Peltier effect of TEG on the TEC–TEG hybrid system, in which TEG is driven directly by TEC. Herein, an experimental setup is built to discover how the Peltier effect produced by the TEG affects the exergy of the TEC–TEG system especially for the included TEC. The temperature variation of hybrid system caused by the Peltier effect of TEG is studied, and the relationship between performance of every single part and the Peltier effect of TEG is revealed. The performance of the hybrid system and the single TEC system is also compared. It is shown in the results that the Peltier effect produced by TEG is beneficial to the operation of TEC in the system. And, the adverse influence of Peltier effect produced by TEG on itself can be compensated. After thermal‐resistance optimization of hybrid system, the total output power of the hybrid system is up to 14.2% higher than that of the single TEC system in same conditions.

Nuclear engineering for monitoring the thinning of the pipe wall of the Angra 1 power plant

Large thermoelectric generation systems based on the Rankine cycle require monitoring of the thinning of the pipe wall caused by steam flow due to aging processes such as erosion and accelerated corrosion processes. Inspection difficulties are related to hostile environments (50 oC and 100% relative humidity) and spaces with complicated geometry, such as pipeline curves and their support structures. This work presents a monitoring program that integrates wall thickness inspections performed with a robotic system and Industry 4.0 technology to process the collected data and disseminate information throughout the organization. The robotic system is developed using “Digital Twin” technology, a very realistic virtual modeling scheme that allows interaction with the real world environment. They include equipment and all the steps to carry out the inspection process. The tube wall thickness monitoring system will be used at the Angra 1 nuclear power plant (Brazil).

Enhanced heat transfer study of thermoelectric generation system based on bidirectional coupling simulation

ABSTRACT To improve the performance of thermoelectric generator (TEG) for recovering the waste heat of thermaI fluid, a fluid-thermoelectric multiphysics numerical model is developed by using a bidirectional-coupled simulation method. The interaction between the thermal fluid and the TEG system is considered in this method and the numerical model is experimentally validated. Two numerical models of TEG systems with straight fins and corrugated fins are established, respectively. The temperature and potential distributions of the TEG at different inlet velocities and temperatures are analyzed. The results show that the corrugated fins can enhance the convective heat transfer, thereby improving the output characteristics of TEG. The developed model can predict the output characteristics of TEG system accurately. The error between the simulated and experimentally measured open-circuit voltage does not exceed 2.41%. Increasing the inlet air velocity and temperature improves the TEG hot side temperature, thus increasing its output power. Compared with the TEG system with straight fins, the heat transfer coefficient of the thermal fluid in the TEG system with corrugated fins was improved by about 10%. The output power and conversion efficiency were also improved by 18.9% and 0.12%, respectively, at a higher inlet velocity of 5.36 m/s.

Electrical and thermomechanical evaluation of the bifacial PV-STEG and tandem PV-STEG units under uniform and nonuniform radiation conditions

The structural failure threats the long-term stable operation of the photovoltaic-solar thermoelectric generator (PV-STEG) system. In this study, a comprehensive numerical model is developed to analyze the electrical and thermomechanical performance of the conventional tandem photovoltaic-solar thermoelectric generator (TA-PV-STEG) layout and bifacial structure of photovoltaic-solar thermoelectric generator (BI-PV-STEG) layout under uniform and nonuniform radiation conditions. The effects of sun concentration ratio (CR), inlet temperature, and leg height on the performance of the systems are examined in detail. In addition, the consequences of utilizing solar cells with varying temperature coefficients (cell1: 0.004 1/K and cell2: 0.001 1/K) and standard efficiencies (cell1: 15% and cell2: 10%) are also accounted for. The results demonstrate that the bifacial structure could provide better overall performance than the tandem structure. The maximum cell temperature difference under uniform radiation is greater than 19 K, and the corresponding percentage increase in cell power output is 9.28%. The increase in CR and leg height leads to higher STEG output, while the lower inlet temperature is preferable. Moreover, although cell2 possesses a lower temperature coefficient, the electrical performance of cell1 is higher than cell2 in most conditions. The maximum thermal stress observed in the bifacial structure is greater than that of the tandem structure due to the wider temperature gradient. Therefore, this study provides direction for designing the actual PV-STEG system in consideration of thermal stress distribution side effects.

Multiphysics Co-Simulation and Experimental Study of Deep-Sea Hydrothermal Energy Generation System

With the continuous deepening of research on seafloor hydrothermal observations, the demand for a sustainable power supply of observation equipment is increasingly urgent. A kind of device that utilizes the temperature difference near hydrothermal vents to provide power is studied. However, the frequent experiments required for in-depth research on this device contradict the rare opportunities for hydrothermal field experiments and the difficulty in laboratory replication. In response to the above difficulties, a multiphysics co-simulation of the deep-sea hydrothermal energy generation system is studied in this paper. Firstly, the output performance analysis and modeling of the TEG installed in the device under pressure are carried out. An enhanced heat transfer model of the system is proposed for the hydrothermal fluids in the flow channel of the device. Then, the thermoelectric model of TEG and the heat transfer model of the device are jointly simulated by using Fluent and Simulink software. Eventually, the simulation data are compared with the data obtained through experiments. The average absolute of the relative error of the open-circuit voltage is 5.07%, and the maximum one is 6.28%. The corresponding values of the maximum output power are 5.16% and 6.79%, respectively. Therefore, the performance of the hydrothermal thermoelectric power generation system and the correctness of the proposed overall co-simulation model are verified.

Temperature-based thermo-electric coupling maximum power point tracking algorithm for thermoelectric generation systems under transient conditions

The applications of thermoelectric generators (TEGs) are expanding from stable to complex environments. Traditional maximum power point tracking (MPPT) algorithms observe the electrical characteristics of TEG, and make judgments based on historical data. In a system with transient temperature conditions, the influence of system temperature on the electrical characteristics of TEG becomes the main effect, which confuses traditional algorithms and causes misjudgment. To address this issue, this paper proposes a temperature-based thermo-electric coupling MPPT (TTEC-MPPT) algorithm that considers temperature information during TEG operation. The algorithm uses Lagrange Interpolation Polynomial to predict the temperature difference of TEG and divides the disturbance step into two parts based on the temperature and algorithm. Experimental results show that the proposed algorithm outperforms four traditional algorithms and three sets of fixed pulse width modulation (PWM) conditions in five different cases, with an average power increase of 11.9211% and 20.1128% compared to traditional algorithms and fixed PWM respectively in transient cases. By considering the effect of temperature, the TTEC-MPPT algorithm has an advantage in dealing with complex transient temperature conditions compared to existing algorithms.

Design and Research of Thermoelectric Generator Simulation System for Boiler Flue Gas Waste Heat

One of the significant factors contributing to high energy consumption is the unutilized waste heat from flue gas in industrial boilers. Thermoelectric generator (TEG) technology can directly convert thermal energy into electrical energy, and has been gradually applied in the field of waste heat recovery due to its simple and reliable structure, environmental protection, and other advantages. In this paper, a thermoelectric generator simulation system of boiler flue gas waste heat is proposed. The experimental platform is designed by simulating the flue gas waste heat temperature condition of boiler, and the structure of cold end module and hot end module is optimized. During the experiment, the fixed temperature difference was set at 120 °C (hot end:150 °C~cold end: 30 °C). An analysis is conducted on the volt-ampere characteristics and output power of the TEG module. The output characteristics of the TEG system are analyzed under the conditions of variable load, constant load, different pump speed, different heat dissipation modes, and series and parallel connection method. The results show that the experimental platform can instantaneously and accurately test the output parameters of the TEG system, and ensure the intended design requirements. When the ratio of the load resistance to the internal resistance of the TEG module is approximately 1–1.15, the output power of the system reaches its maximum. In order to optimize the output power of the TEG system, a power prediction-based adaptive variable step size maximum power point tracking (MPPT) algorithm is introduced. Additionally, a corresponding mathematical model is formulated. Simulations demonstrate that the time of the improved algorithm to reach the stable maximum power point is 1.54 s faster than that of the traditional algorithm. The improved MPPT algorithm satisfies the criteria for speed and accuracy, diminishes superfluous energy waste, and enhances the overall system efficiency. The research results have certain guiding significance for the design and application of subsequent TEG system.

A comprehensive hybrid transient CFD-thermal resistance model for automobile thermoelectric generators

This paper proposes a comprehensive hybrid transient CFD-thermal resistance model to predict the dynamic behaviour of an automobile thermoelectric generator (ATEG) system. The model takes into account the temperature dependences, the topological connection of thermoelectric modules, and the dynamic characteristics, which has the merits of high accuracy and short computational time. The dynamic behaviour of the ATEG system is determined and thoroughly examined using the transient exhaust heat as the heat source input. According to the transient model results, the dynamic output power of the ATEG system keeps the same variation trend with the exhaust temperature, but the variation of output power is more stable. Under the whole driving cycle, the mean power and efficiency of the 1/4 ATEG system are 8.91 W and 3.39% respectively, which are 3.39% lower and 47.52% higher than those expected by steady-state analysis. Beside, the model is validated experimentally, and the mean deviations of the output voltage and outlet air temperature are 7.70% and 1.12% respectively. This model is convenient to evaluate the behaviour of the ATEG system under different topological connections and gives a fresh tool for assessing the dynamic behaviour of ATEG systems.

Hybrid General Regression NN Model for Efficient Operation of Centralized TEG System under Non-Uniform Thermal Gradients

The global energy demand, along with the proportionate share of renewable energy, is increasing rapidly. Renewables such as thermoelectric generators (TEG) systems have lower power ratings but a highly durable and cost-effective renewable energy technology that can deal with waste heat energy. The main issues associated with TEG systems are related to their vigorous operating conditions. The dynamic temperature gradient across TEG surfaces induces non-uniform temperature distribution (NUTD) that significantly impacts the available output electrical energy. The mismatching current impact may lower the energy yield by up to 70% of extractable thermal energy. As a solution, a hybrid general regression neural network (GRNN) orca predation algorithm (OPA) is proposed; backpropagation limitations are minimized by utilizing the stochastic optimization algorithm named OPA. The conclusions are evaluated and contrasted with highly improved versions of the conventional particle swarm optimization (PSO), grey wolf optimizer (GWO), and Harris hawk optimization (HHO). A detailed analytical and statistical analysis is carried out through five distinct case studies, including field stochastic data study, NUTD, varying temperature, and load studies. Along with statistical matrix errors such as MAE, RMSE, and RE, the results are assessed in terms of efficiency, tracking, and settling time. The results show that superior performance is achieved by the proposed GRNN-OPA based MPPT by 35% faster tracking, and up to 90–110% quicker settling time which, in turn, enables the 4–8% higher energy accumulation over a longer period of operation. A low-cost experimental setup is devised to further validate the practicality of the proposed techniques. From such comprehensive analysis, it can be safely concluded that the proposed GRNN-OPA successfully undertakes the drawbacks of existing classical MPPT methods with higher efficiency.