Thermoelectric Generator System Research Articles

Photothermal catalytic hydrogen production coupled with thermoelectric waste heat utilization and thermal energy storage for continuous power generation

Photothermal catalytic water splitting is a potential way to produce renewable hydrogen. However, low-grade heat converted from solar energy in the photochemical process is inevitably dissipated to the environment and often wasted. Besides, the intermittency of solar energy causes the devices unable to work continuously. Here, a novel integrated solar to hydrogen-electricity and thermal storage system (STHET) is proposed to solve above problems. STHET consists of a photothermal catalytic system and a thermoelectric generator (TEG) system, which can realize hydrogen-electricity co-production and thermal self-storage. Photothermal effect in STHET is increased by recycling scattered light, leading to an enhancement of 22.7% in hydrogen production than the traditional system without TEG. Meanwhile, the maximum power of waste heat utilization by TEG is 193.53 μW. Furthermore, since strengthened heat exchange in STHET with forced cooling, the output power of TEG can improve to 1578.13 μW, and hydrogen production is reduced by only 1.4% than the traditional system without TEG. Additionally, STHET can continuously generate power using stored thermal by the liquid reaction system to achieve continuous working in the dark, in which 19% (maximum proportion) of the electrical energy output can be obtained at night. The heat exchange methods in STHET can be flexibly selected according to the requirement for hydrogen energy and electric power. As a conceptual model, STHET can also be promoted in other solid-liquid reaction systems.

A nanofluid-based hybrid photovoltaic-thermal -thermoelectric generator system for combined heat and power applications

This study investigates the use of nanofluid-cooled Thermoelectric Generators (TEGs) integrated with a Photovoltaic (PV) panel to enhance the overall energy efficiency of the system. Three cooling fluids — Water (W), CuO/W single Nanofluid (NF), and CuO-Fe/W hybrid NF — are examined at various flow rates for cooling the PV panel. The research studies the PVT-TEG-NF system considering both normal and concentrated solar irradiation in a 3D parallelly-cooled heat sink setup and comparing its electrical and thermal performance, which has not been previously addressed in the literature. The results demonstrate that by utilizing CuO-Fe/W, the PV temperature at irradiation of 935 W/m2 in the summer can be maintained at 31.7 °C, which is 8.8 % and 13 % lower than those achieved by using CuO/W and water, respectively. For 0.08 m/s of CuO-Fe/W inlet velocity, the total output power PV-TEG is about 9.5 W, with a heat removal rate of ∼37.2 W. Additionally, by utilizing the CuO-Fe/W compared to water, the combined efficiency of the system (the ratio of electrical and thermal power output to solar input) increases from 66.7 % to 76.7 %. In the second part, the study introduces a new approach to maintain a steady PV efficiency while increasing solar concentration by adjusting the cooling fluid flow rate. By increasing solar concentration from 1.5 suns to 2.5 suns, the PV temperatures could be maintained at 44.5 °C and 51.5 °C using CuO-Fe/W and water with 0.12 m/s of inlet velocity, respectively. This made it possible to enhance the power output of the PV and TEGs by 65.9 % and 187 %, respectively, by using CuO-Fe/W as coolant, while the temperature of the panel could be maintained at a safe level.

Design of A Thermoelectric Generator System for Coupling in Air Conditioning Equipment’s

Banking digitalization requires the use of IT tools. In this paper, we propose to use a programming tool "R studio". Indeed, this research consists of simulating the loan calculation using R shiny. The simulator operation show through screenshots of some application interfaces. The loan calculation simulator allows you to evaluate the amount of a loan or the amount of a monthly payment of a borrower based on several variables: the rate, the amount, the monthly payment and the repayment period.

A Novel Optimization Method for TEG System Performance Based on Temperature and Heat Flux

The thermoelectric generator (TEG) can convert heat to electricity and is widely used. To overcome the limitation for low efficiency of thermoelectric materials, optimizing the performance of TEG in given system is necessary. This study proposes a method to match individual TEG components to the system environment based on two boundary conditions—temperature and heat flux. With this method, TEG geometrical parameters can be determined to optimize the system performance by varying temperature as an independent variable. Using this method, the TEG in an undersea Radioisotope thermoelectric generator (u‐RTG) is optimized. The TEG system exhibits an output power of 14.10 W when powered by a 200 W heat source. The simulate result in the comprehensive system model of u‐RTG is 14.04 W, which has 0.45% deviation from the TEG optimization result. It is proved that the TEG optimized by this method matches the system, the optimization results are accurate.

Study on the performance of semiconductor thermoelectric generator system driven by salt gradient solar pond

Study on the performance of semiconductor thermoelectric generator system driven by salt gradient solar pond

Study on the performance of semiconductor thermoelectric generator system driven by salt gradient solar pond

Study on the performance of semiconductor thermoelectric generator system driven by salt gradient solar pond

Power generation prediction of a geothermal-thermoelectric hybrid system using intelligent models

This study focuses on the most effective use of energy resources, which is the main goal of sustainable energy systems. The first contribution of the research is to ensure that the waste and geothermal fluids generated during the geothermal energy production process are evaluated in the most efficient way and reused for energy production. For this purpose, a geothermal-thermoelectric hybrid experimental system has been designed to produce electrical energy through heat exchange and how waste thermal energy could be reused in this process has been examined. Experimental tests have been performed under electrical load and in the presence of real-time uncertainties such as temperature changes, thermal conductivity, electrical noise, heat losses and random variations in thermal interaction. The second main contribution of the study is to predict and evaluate different power generation performances in the Thermoelectric Generator (TEG) system, which is affected by the mentioned experimental limitations based on artificial intelligence models. In addition, the optimal prediction performance of artificial intelligence models using hyper-parameter optimization has also been compared. Experimental results have shown that intelligent models are a successful tool for energy prediction in geothermal power generation. As a result of the hyper-parameter optimization, each model is improved by ∼5 % to ∼30 % in various error metrics. However, it was observed that the decision tree-based learning techniques resulted in ∼46 % to ∼96 % less inaccurate predictions on various error metrics compared to other methods. Power production predictions obtained using intelligent models have been obtained with 98.7 % accuracy with LightGBM learning algorithms. Most of the models used to classify different hot and cold water levels exhibit very high classification performance. The results show the successful integration of artificial intelligence models in effectively utilizing waste thermal energy and adopting a sustainable approach to energy production.

Generation of Current in Thermoelectric Generator by Absorption of Heat Using ANSYS Thermal

Thermoelectric power generation is a renewable energy conversion process that directly converts heat to electricity. This research proposes a novel fluid-thermal-electric multi-physics numerical model for predicting the performance of a thermoelectric-producing system. On the ANSYS platform, numerical simulations are done along with the exhaust temperature and mass flow rate. The range of hot end temperatures is from 100 to 450 degrees Celsius. Similarly, the cold end temperature can reach a maximum of 25 degrees Celsius and a minimum of 10 degrees Celsius. When the temperature at the generator's hot end rises, it means the temperature at the generator's cold end must fall. It means both have an inverse relation to each other. The maximum heat absorbed at the hot junction is 32.762 W and the minimum heat absorbed at the hot junction is 4.6305 W. Hence the maximum and minimum current values produced in this paper by the thermoelectric generator are 72.156 A & 10.816 A respectively. The hot side heat exchanger's position of the thermoelectric modules has a significant impact on output. Combining the benefits of many models are advised to construct an inclusive thermoelectric generator system for use in real-world applications.

Optimal design of a solar-driven Kalina system for combined power and desalination purposes

This research study presents a thermodynamic simulation and exergy analysis of a solar-powered Kalina cycle that is integrated with a reverse osmosis desalination (RO) module and a thermoelectric generator (TEG) system. A parabolic through solar collector (PTSC) provides the required heat to drive designed plant. The thermodynamic simulation and exergy examination of the proposed system are carried out using the Engineering Equation Solver (EES). A parametric study of the presented plant to show the primary parameters impacts on the system operation is conducted. The system in this study generates 212.7 kW of electrical power and 44.46 m3/h. The total energy efficiency of the plant is 24.3 %. The inlet thermal energy from PTSC is 876.5 kW. In addition, the thermoelectric module generates 7.26 kW electrical power. Carried out analyses show that the recuperator has the most significant exergy destruction rate among all system components, with 303.2 kW. The unit responsible for the second major exergy destruction value associated with the RO unit, which accounts for 74.22 kW. To examine the influence of influences of parameters like direct normal irradiance (DNI), turbine inlet pressure, and mass flow rate of the Kalina cycle the system case study is presented. It can be observed that increasing DNI parameter from 750 W/m2 to 1000 W/m2 leads in a net output power increment from 279.1 kW to 372.1 kW and increasing fresh-water production from 41.64 m3/h to 48.09 m3/h. Moreover, the calculation shows that increasing DNI has a positive impact on the TEG unit output power too. Enhancing the inlet turbine pressure increases both net output power and fresh-water production by reverse osmosis unit while this increment diminishes the thermoelectric unit electrical output. It can be observed that increasing turbine inlet pressure from 110 kPa to 200 kPa, increases net output power and fresh-water production by about 6.08 % and 3.5 %, respectively.

Three dimensional numerical study of PV module cooling by using thermoelectric effects and nano-enhanced confined multiple slot jet impingement

In this study, 3D numerical study of photovoltaic (PV) module cooling is analyzed by combined utilization of thermoelectric generator (TEG) and nano-enhanced slot jet impingement system. For the relevant parameters of interest, such as Reynolds number (between 10 and 100), nanoparticle loading (solid volume fraction between 0 and 0.02), non-dimensional vertical distance between the slots and upper plate (between 2.5 and 8), non-dimensional spacing between the slots (between 2.5 and 8), and cold NF inlet temperature (between 20oC and 30oC), finite element method is utilized. Using only TEG and nano-jet assisted cooling with TEG result in PV-cell temperature reduction by about 43.33oC and 69.55oC as compared to un-cooled PV module. It is observed that cell temperature decreases by about 2.4oC-2.9oC when considering the minimum and maximum Reynolds number cases. When nanoparticle loading is increased to 0.02, output TEG power rises while cell temperature decreases by about 0.75oC. When varying the vertical distance between the slot to the impinging surface, cell temperature changes up to 1.9oC while distance between the slots has very slight impact on the temperature variation. Decreasing the inlet fluid temperature by about 10oC decreases the cell temperature by about 8.5oC.

Waste heat regeneration from thermoelectric generator based improved biomass cookstove (TIBC): Modelling of TEG system utilizing DC-DC converter with fuzzy logic MPPT

Most of the people in the rural areas cook their food in traditional biomass cookstove which emits a lot of emission that leads to poor health of the women and children. This paper points out a technology that utilises a thermoelectric generator (TEG), which converts thermal energy into electrical energy directly. A TEG is a small plate made of semiconductor p-n junctions connected electrically in series and thermally in parallel. The difference in temperature produced on the hot side and cold side of the TEG is proportional to the voltage generated. The TEG is integrated into the wall of the inner combustion chamber of the biomass cookstove with the help of heat plate and the cold side of the TEG is connected to a flower-type heat sink to maintain the temperature difference. The power generated by the TEG is used to drive a 12 V DC fan which helps to keep the cold side of the TEG relatively cooler and direct the same air inside the inner combustion chamber of the cook stove through holes to increase the air-to-fuel ratio. As a result, it improves the cookstove's combustion, thereby reducing emissions and increasing thermal efficiency. For testing the efficiency of the TEGs available in the market, a hit and trial method is used by taking TEGs of different specifications and connecting them to a hot side and a cold side test bed and then finally the performance is realized. Therefore, for every different TEG, a hardware has to be made for final conclusion of the result. To eliminate the hit and trial method, the electrical characteristics of thermoelectric generator module has been analysed by modeling a TEG module in MATLAB/Simulink and implementing it with fuzzy logic control (FLC) based MPPT utilizing a DC-DC boost converter with a constant as well as variable load. This fuzzy logic-based scheme exhibits fast dynamic response and precisely tracks the maximum power point (MPP) from TEG under varying load conditions. Based on the robust performance of the obtained simulation results, the TEG module is integrated and tested in the laboratory using a thermoelectric generator based improved biomass cookstove (TIBC). The novelty lies on the concept of using MATLAB/Simulink platform by modeling the FLC based MPPT incorporating boost converter to test the performance of TEG module for its integration with TIBC and eliminating traditional hit and trial method. This TIBC is able to power the fan directly within just 2–3 min using the electricity generated by the TEG module. The maximum power generated from the TIBC is 6.25 W using a single TEG. The fan requires 1.4 W and rest of the power was used to charge auxiliary battery.

Optimization of segmented thermoelectric power generators from waste heat while considering the influence of temperature on materials

Thermoelectric technology is commonly used in waste heat utilization of automotive internal combustion engines and widely combined with solar energy units to form solar thermoelectric generator systems. The structure of the Thermoelectric Generator (TEG) needs to be optimized in order to obtain better performance for wider applications. In this paper, the influence of temperature on the height of PN-type thermoelectric arms was analyzed using an improved one-dimensional heat conduction model with the calculus method. At the same time, both the calculation formula of the maximum output power and the calculation formula of various size parameters of the TEG was derived when the influence of temperature on the performance of thermoelectric materials has been considered. In addition, the relationships among different size parameters were derived to obtain the maximum efficiency. The relationships include the most commonly used classical optimization relationship, that is, when the Seebeck coefficient, thermal conductivity and resistivity are averaged, the relationship is consistent with the classical optimization relationship. By considering the impact of temperature on the performance of thermoelectric materials, an improved calculation formula of the figure of merit (Z) was also given. The new optimization formula was compared with the classical optimization method by taking the maximum output power as the optimization index. In the case study, the temperatures of the cold end and the hot end were set at 330 K and 700 K, respectively. PbTe and PbSe were used as the materials with intermediate temperature, and Bi2Te3 was used as the material with low temperature. Through theoretical analysis, it is found that the maximum output power of the new optimization formula can be higher than that of the classical optimization formula.

Energy and exergy analysis of a thermoelectric generator system for automotive exhaust waste heat recovery

Thermoelectric generators are a viable solution for recovering and producing energy utilizing wasted energy in automotive exhaust. Exergy analysis can help identify irreversible losses that occur during the transfer of exhaust energy, which is essential for comprehending and developing exhaust thermoelectric generator systems. In this study, we proposed a model based on thermodynamic of the exhaust thermoelectric generator and conducted energy and exergy analyses. The results indicate that convective heat transfer exergy loss and PN junction thermal conductivity exergy loss are the primary exergy losses of the exhaust thermoelectric generator, accounting for more than 52.0 % of the total. Increasing the temperature of exhaust can boost the performance of systems, but it may also reduce the proportion of available energy obtained by the cooling water. When the exhaust heat transfer coefficient is increased to 300, the convective exergy losses of the exhaust can be reduced to 17.6 %, resulting in an overall exergy efficiency of 38.8 %. Furthermore, by increasing the exhaust flow rate from 10 g/s to 50 g/s, the power generation capacity has increased by a factor of 6.87, with little change in exergy losses. These findings are valuable for developing high-efficiency exhaust power generators.

Modelling and preliminary thermal study of a fed-by-laser thermoelectric generator system on board of a 3U CubeSat

Modelling and preliminary thermal study of a fed-by-laser thermoelectric generator system on board of a 3U CubeSat

Transient exergy analysis of ejector cooling and thermoelectric generator systems using heat storage and parabolic trough collector for residential buildings

The large amount of energy consumption has attracted the attention to exploiting renewable energy sources, the most significant of which are solar energy applications in hot climates to meet the demands of cooling and power. The novelty of the present study lies in applying transient exergy analysis to two ejectors and two evaporators in an ejector cooling cycle. Furthermore, the study uses solar data specific to Tehran in Iran. Third, by absorbing waste heat from the hot parts of the condenser, the thermoelectric generator system provides the energy needed to run the pumping and electrical control systems, thereby creating a fully autonomous system. Thermodynamic model have been designed using EES software. The results of Sandia National Laboratory (SNL) and the National Renewable Energy Laboratory (NERL) have validated the parabolic trough solar model. The comparison with the experimental data collected by SNL during the LS-2 tests on the AZTRAK platform has shown good agreement. Weather conditions were analyzed as transients using Meteonorm software. The results show that the solar system produced the most heat in June and the least in December, with 816 kW and 262.3 kW, respectively. Additionally, production power and cooling in June are 5.9 kW and 86 kW, and in December: 2.7 kW and 28 kW. Regarding exergy destruction percentages, the solar collector has 86% and the storage tank has 6.5%.

Global sensitivity analysis and optimization of a multistage thermoelectric generator based on failure probability

Thermoelectric generator (TEG) is a thermoelectric conversion device that mainly utilizes the Seebeck effect, and the electrical energy generated is usually directly converted from thermal energy. However, research on the global sensitivity analysis and optimization of three-stage TEG systems is currently lacking. In this study, a multistage semiconductor TEG system model based on functional failure probability and a global sensitivity analysis model were established. These models are first used to compare the performance of TEG configurations with different stages. Then, based on the double random uncertainties of design variables, a series of studies were conducted. The results showed that the performance parameters of the all TEG configurations exhibited similar performance variation trends. An first-best working current was identified to obtain the first-best output power and conversion efficiency. Next, as the sample size used to determine the variable uncertainty for a three-stage TEG increased, it increased to 4 × 106, the sensitivity indicators of the output response (P and η) tended to constant values of 0.02322 and 0.02039. Among the 11 considered design parameters, the uncertainties of the heat and cold source temperatures had the most significant influence on the functional failure probability of the three-stage TEG system, followed by the working current, Zeebek coefficient, number of temperature difference components in each stage, and heat transfer coefficient of the cold source. The remaining variables had negligible influence. Finally, small changes in the mean heat and cold source temperatures changed the sensitivity of the output response of the three-stage TEG to each critical design variable, but did not affect the relative ranking of the sensitivity indicators corresponding to each. The results of this study can provide some basis for the further development of TEG systems.

Experımental investıgatıon and mathematıcal modelıng of a novel solar thermoelectrıc generator incorporated with thermal condensing system

This study presents an investigation of the electrical energy output capability of a new thermoelectric generator system and reports on its design and fabrication. It was aimed to increase the current and voltage values by connecting six thermoelectric generators (TEGs) in series and parallel using a system with efficient thermal conversion. In this way, usable electrical energy was produced. The constructed system consists of heat pipes with solar glass tubes for collecting solar irradiance, a heat exchanger with an active cooling system for cooling, thermoelectric (TE) modules that were sandwiched between the upper heat chamber and heat sink, and a lower heat chamber adapted to heat pipes. The efficiency of electrical energy production in the system depends on the proper circulation of the working fluid in the system and active cooling. Numerical parameters such as open circuit voltage, solar irradiance and temperature values were collected from various parts of the constructed system, while electrical parameters such as short circuit current, maximum power output and Seebeck coefficient were obtained through calculation. Experimental measurements were taken at 41° 14′ N, 36° 26′ E with sea level on August 1, 6, and 8, 2019 and July 2, 3, and 4 of 2020. The data was collected from 8 a.m. to 3 p.m. The data of July 2 and 3, 2020, with the greatest numerical values, were used in the experimental presentation. The highest value of open circuit voltage was obtained 7.52 V on July 3, 2020, whereas the solar irradiance value was measured 662 W/m2. As a result, the value of maximum output power was calculated as 5.236 W. Following the experimental investigation, a numerical model with TEGs and a hybrid cooling system was developed. The developed model was validated against the data of open-circuit voltage, cold side and water outlet temperatures obtained from six different experimental tests. When the findings were analyzed, it was discovered that the developed model produced results that were compatible with the experimental measurements.

Metaheuristic based single and multiobjective optimization of thermoelectric generator

Analytical optimization methods are not applicable for some complex practical problems that lead to explore the numerical/metaheuristic optimization methods. Thermoelectric devices are also complex systems and need metaheuristic methods for their performance optimization. This paper analyses various metaheuristic techniques for performance optimization of thermoelectric generator (TEG). Single and multiobjective optimizations of TEG have been performed to optimize its power output and efficiency. The hot and cold side temperatures, load resistance, length of semiconductor legs, and fill factor of the TEG are used as performance parameters. Single-objective optimization is performed using 13-metaheuristic algorithms and their results are compared in terms of solution optimality and computational time acceptability. It has been observed that the cuckoo search (CS) algorithm is the most suitable in terms of accuracy and speed. CS produced the optimum power output and efficiency of 19.20837 W and 2.4427 % respectively in minimum time. The multiobjective optimization is also performed for simultaneous optimization of the power output and efficiency. Shannon entropy approach is found to be the best technique to determine optimal point on the Pareto front for multiobjective optimization. The optimal values of decision variables, Th Tc, RL, L and FF for multiobjective optimization are found to be 321.195 K, 281.195 K, 0.14250 Ω, 0.5 mm and 0.9 respectively and it produced optimum power output and efficiency of 19.20837 W and 2.25932 % respectively. The statistical and box plot analysis have also been carried out for all the algorithms. The determination of the most suitable algorithm for the faster performance optimization of the TEG, hereby provides the pathways to ascertain the most accurate solution for the power output and efficiency obtainable from the TEG system and hence, delivering the ability to decide the right parameters for the construction of the TEG system with the best performance.

Experimental investigation of a thermal energy storage unit integrated with thermoelectric generators under solar radiation

In this present study, a phase change material (PCM) based thermal energy storage unit (TESU) integrated with thermoelectric generators (TEGs) was experimentally investigated under artificial solar radiation. Within the scope of the experiments, a TESU with the dimensions of 15x15x5 cm was designed by assembling nine TEGs connected in series on the TESU. In the design, two types of paraffin based PCM with different thermophysical properties values as PCM in TESU and two models of TEGs with different power were used. Four different TEG/TESU designs with different parameters were made, namely TEC1-12706/P1, TEC1-12706/P2, TEC1-12710/P1, and TEC1-127010/P2. Charge-discharge processes of each design were investigated under radiation intensities of 800, 1000, and 1200 W/m2. According to the results of the experiments, it was observed that as the power of the TEG used increased, the melting time of the paraffin was shortened, and the energy conversion efficiency (ECE) and the thermal energy storage efficiency (TESE) increased. It was determined that the maximum power obtained from the designs with TESU was approximately 11 % higher than that without TESU. The result showed that more efficient TEG systems would be obtained by making the temperature of the cold surface of TEGs more stable with PCM. In addition, it was determined that the melting time decreased and the TESE and ECE increased with the increment of the radiation intensity. The shortest melting time of 135 min, the highest TESE of 80.72 % and the highest ECE of 2.32 % were obtained from the TEC1-12710/P2 design under 1200 W/m2 radiation. The longest melting time of 240 min, the lowest TESE of 64.62 % and the lowest ECE of 2.04 % were obtained from the TEC1-12706/P1 design under 800 W/m2 radiation.

Study on heat exchanger structural optimization of stationary engine thermoelectric generator system

Thermoelectric generators have received considerable involvement in recovering the wasted heat from internal combustion engines (ICE). However, the power of the thermoelectric generator system (TGS) on an ICE is minimal compared with the exhaust energy. This study investigates the effects of heat exchanger structural parameters, including the fin quantity, fin height, and fin thickness, on the performance of the TGS utilizing the emission gas from a stationary diesel engine to find the optimal set of parameters that produce the maximum performance. The numerical method is adopted to determine the total output and pressure loss powers of the TGS with various fin quantities, heights, and thicknesses at three engine operating modes. The tradeoff ratio is utilized to compare the performances of different TGS structures to account for their pressure drop effect on engine power reduction. The results reveal that the output power of TGS increases when the fin quantity, thickness, and height rise. However, when the number of fins is large enough, it reduces with the rise of fin height. Pressure loss increases with the increasing fin quantity and thickness but decreases with increasing fin height. The set of optimal parameters found in this work is the heat exchanger with 28 fins, a fin height of 40 mm, and a fin thickness of 1 mm. Thanks to the optimal heat exchanger, the TGS output power increased to 45.39% compared with the worst case in the considered range. This optimization is necessary because it achieves the highest performance and makes the TGS more compact and affordable price. This result is the critical basis for designing and manufacturing the TGS prototypes for future experimental studies.