Hybrid Thermoelectric Generator Research Articles

ANALYSIS THE EFFECTIVENESS OF THERMOELECTRIC POWER GENERATION USING WASTE HEAT RECOVERY

Non-renewable energy resources, which account for about 85% of worlds’ energy (68% fossil fuels are used for electric power generation), are getting exhausted rapidly. As predicted by the Institute of Sustainable Energy Policies, by the year 2050, only 33% of non-renewable energy resources will be available for electric power generation. Hence, to meet the required demand, the remaining 67% has to be replaced by renewable energy sources. This demand in electric power generation has to be met by a pollution free, low-cost, clean energy resource, which is the need of the hour. The present research targets towards two main applications for generating power using the biomass energy based resources. They are domestic based application – burning biomass wood and utilizing the heat for generating power, industrial based application – combustion of gasified de-oiled Pongamia cake and utilizing the heat energy for generating power In order to achieve the proposed target, initially, the theoretical modeling on the performance of (Bi2Te3-PbTe) hybrid thermoelectric generator (TEG) composed of n-type Bismuth Telluride - p-type Lead Telluride semiconductor materials has been done. The effect of different performance parameters on the maximum conversion and power efficiencies have been theoretically analyzed by varying the hot side temperature. Key Words: Hybrid Thermoelectric Generator, Electric Power Generation, Graphene Nanoparticles.

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.

Energy impact of heat pipe-assisted microencapsulated phase change material heat sink for photovoltaic and thermoelectric generator hybrid panel

As the importance of energy saving continues to increase owing to climate change, various Internet of Things sensors, related to building temperatures, humidity, and energy usage, are being employed in buildings, such as in building energy management systems. Aiming to satisfy the rapidly increasing electric energy demands of buildings, studies have combined various building-integrated photovoltaic (BIPV) and thermoelectric generators (TEGs) to recover sunlight and heat wasted from building envelopes. However, in most previous studies, active methods for heat rejection were applied to increase the temperature difference between both ends of the TEG and cooling of the solar panel. The actual constructability problems, such as leakage problems, were insufficiently addressed. Therefore, this study proposed a BIPV-TEG system with increased constructability and heat dissipation efficiency using a heat pipe and microencapsulated phase change material (mPCM). In addition, this study analyzed the thermal behaviors and improvements in power generation efficiency through field tests by manufacturing a prototype. The results of the outdoor experiment indicated that the BIPV-TEG-PCM prototype improved power generation efficiency by approximately 2% in the intermediate season and 2.5% in the summer relative to the efficiency of a general PV panel. Moreover, using a single TEG, approximately 3.06 Wh of the heat wasted in the building envelope can be recovered as a form of electricity annually.

Performance evaluation of a hybrid thermoelectric generator and flat plate solar collector system in a semi-arid climate

This study investigates the performance of a hybrid system that combined thermoelectric generators (TEG) with a solar flat plate collector system (SFPC) to turn more renewable energy into useable energy under normal operating and environmental conditions. A multi-month case study was first time conducted to explore the performance of SFPC with and without TEGs under the cold climatic conditions of Abha, Saudi Arabia. The result demonstrates that the heat losses from the rear surface of the SFPC's absorber plate were effectively utilized by TEGs, thereby decreasing overall heat losses and increasing the SFPC's overall thermal efficiency. Further, it was found that adding TEGs at the rear surface of SFPC's absorber plate improves thermal efficiency and exergy efficiency by 8.4% and 1.3%, respectively. The hybrid TEG-SPFC system can turn waste heat into useable electricity, with a peak power output of 2.2 W at midday. Maximum power was generated around midday, when the temperature differential between the upper and lower layers of TEGs was greatest. In addition, it was noticed that the thermal efficiency of the SFPC diminishes when the inlet water temperature rises. A hybrid TEG-SFPC system's exergy efficiency depends on ambient temperature variation and solar irradiance.

Machine Learning Analysis on the Performance of Dye-Sensitized Solar Cell—Thermoelectric Generator Hybrid System

In cases where a dye-sensitized solar cell (DSSC) is exposed to light, thermal energy accumulates inside the device, reducing the maximum power output. Utilizing this energy via the Seebeck effect can convert thermal energy into electrical current. Similar systems have been designed and built by other researchers, but associated tests were undertaken in laboratory environments using simulated sunlight and not outdoor conditions with methods that belong to conventional data analysis and simulation methods. In this study four machine learning techniques were analyzed: decision tree regression (DTR), random forest regression (RFR), K-nearest neighbors regression (K-NNR), and artificial neural network (ANN). DTR algorithm has the least errors and the most R2, indicating it as the most accurate method. The DSSC-TEG hybrid system was extrapolated based on the results of the DTR and taking the worst-case scenario (node-6). The main question is how many thermoelectric generators (TEGs) are needed for an inverter to operate a hydraulic pump to circulate water, and how much area is required for that number of TEGs. Considering the average value of the electric voltage of the TEG belonging to node-6, 60,741 pieces of TEGs would be needed, which means about 98 m2 to circulate water.

Variance-based global sensitivity analysis of a hybrid thermoelectric generator fuzzy system

In this paper, Hybrid thermoelectric generators (HTEG) model was established based on nonequilibrium thermodynamics and Newton's heat transfer law. Fuzzy theory was used to describe the decision-making and cognitive uncertainty of HTEG design variables in working environment and material. The influence of the fluctuation of design parameters on the output performance is studied using a variance-based global sensitivity analysis. Taking a sampling sample N = 10,000, the main and total Global sensitivity indices of design parameters are calculated, and the sensitivity ranking are obtained. In addition, the analysis was applied to contact effects and the number of serial and parallel components on the sensitivity of the output to the uncertainty of the design variables. The results show: the heat and cold source temperature, load resistance and Seebeck coefficient had a greater impact on the output power and the impact on the conversion efficiency mainly came from the heat and cold source temperature, load resistance and thermal resistance of the thermoelectric module. The contact effects and the number of thermoelectric components connected in series and parallel exerted a certain influence on the uncertainty of output response. The results can be used to guide the performance analysis and parameter optimization of HTEG in application.

Performance Comparison Between Hot Mirror and Cold Mirror as a Beam Splitter on Photovoltaic - Thermoelectric Generator Hybrid Using LabVIEW Simulator

Solar energy can be converted into electrical energy using photovoltaic (PV) and thermoelectric generators (TEG). In order to increase the effectiveness of energy absorption, a hot mirror or cold mirror spectrum separator is used. In this study, a simulation was carried out to see the effect of the cold mirror and hot mirror spectrum separator on the performance of the PV-TEG hybrid. Simulations are carried out using the LabVIEW program. The standard for the solar radiation spectrum used is AM1.5D. The incoming radiation is transmitted using a Fresnel lens to make it more focused and then transmitted to a cold mirror or hot mirror, where the spectral irradiance will be halved. Spectral irradiance with a wavelength of 400-690 nm will be directed to PV and a wavelength of 710-1150 nm will be directed to TEG. From the PV-TEG hybrid modeling and simulation using the LabVIEW program, the resulting power and efficiency are 240.635 W/m2 and 27% respectively for cold mirror and 228.835 W/m2 and 25.76% for hot mirror.

Energetic and exergetic analysis of solar photovoltaicthermoelectric generator hybrid system

The objective of present study is to determine the energy and exergy performance of the developedSolar Photovoltaic- Thermoelectric generator hybrid system. The experimental setup was examined under Udaipur climatic conditions (24°352 73 N; 73°422 453 E). The hybrid systems convert sunlight into electric power by the PV module and then utilize the rest thermal energy by the TEG module. Based on the first law of thermodynamics, the energy analysis is used to evaluate the output performance of the hybrid system. And the output electric power of the hybrid system is calculated. Moreover, the second law of thermodynamics is applied to the exergy analysis of the hybrid system. The exergy losses caused by the irreversible process of solar radiation converted into electric power and thermal energy are evaluated. The calculation results demonstrate that exergy of system follows the incident solar radiation and most of the input exergy has been lost at output with maximum losses occur when solar radiations are converted into heat.

Comprehensive Study and Realizing an Enhanced Efficiency of the Thermoelectric Generator Along with Its Thermomechanical Properties

This paper proposes a real-time simulation model to simplify the research and outcome of a portable thermoelectric generator (TEG) system in real conditions. Consequently, the model is divided into three parts: conventional, segmented, and hybrid TEG systems. The conventional TEG system consisted of Bi2Te3 as the p-type and the n-type materials, whereas the segmented and the hybrid TEG systems consisted of a different combination of materials, including PbTe and Sb2Te3. The optimization of the TEG system length was carried out to achieve the highest power output, which was found to be 2 mm. In addition, thermomechanical stress distribution analysis of the module was conducted to determine the maximum load the TEG system could withstand before undergoing fracture, depending upon the yield strength of the material. The stress was analyzed in all three TEG systems, and the results were evaluated. Results were observed from the optimized length at 2 mm. The conventional, segmented, and hybrid TEG systems showed maximum power output of 147.122 mW, 171.934 mW, and 550 mW, respectively, with a temperature difference at 50 K.

Comprehensive Review of Methods and Instruments for Photovoltaic–Thermoelectric Generator Hybrid System Characterization

Finding new sustainable energy sources or improving the efficiencies of the existing ones represents a very important research and development direction. The hybridization approach is one solution for increasing the efficiency of the existing energy sources. In the case of photovoltaic technology, the hybridization of the photovoltaic panels (PV) with thermoelectric generators (TEGs) has become a more interesting solution for the research community in the last decade. Thus, a comprehensive review of the characterization methods and instruments used in PV-TEG hybrid system study represents the objective of this work. PV and TEG equivalent circuits are presented. The instruments and software applications used for the measurements and simulations are presented and analyzed. The analysis of the literature reveals that there are many papers that offer partial or no information about the instruments used or about the measurement quality (accuracies, uncertainties, etc.). In hybrid system modeling, the preferred software applications are MATLAB (MathWorks, Natick, MA, USA) and COMSOL Multiphysics (Comsol, Burlington, MA, USA), while for experimental studies based on computers, LabVIEW (NI, Austin, TX, USA) is preferred. This review work could be interesting for researchers and engineers who are interested in finding solutions for characterizing or monitoring hybrid system components, but it is not limited to these.

Performance analysis of alkali metal thermoelectric converter and segmented thermoelectric generator hybrid system based on a comprehensive model

The conceptual hybrid system combined alkali metal thermoelectric converter (AMTEC) and segmented thermoelectric generator (STEG) is a promising static thermal to electric conversion system. A comprehensive model and an effective iterative numerical solution method for the AMTEC/STEG hybrid system have been developed in this paper. The comprehensive model includes the AMTEC unit model and the STEG unit model. The good agreement between the model calculation results and those provided in the published reference show the correctness and accuracy of the models. The effect of beta’’ alumina solid electrolyte (BASE) temperature and condenser temperature on the system performance, the load following characteristic and nominal operation conditions have been investigated using the comprehensive model in this paper. According to the performance analysis results, 1173 K and 653 K are selected as BASE and condenser temperatures. When system input power is 249 kW, the peak conversion efficiency can reach 34.2%. The nominal operation point has been selected according to the optimal performance parameters and load following characteristic of the hybrid system, at the nominal operation point, the system electric power, conversion efficiency, current and voltage of AMTEC and STEG can reach 84 kW, 34.2%, 165.5 A, 448.3 V, 51.7 A, 356.5 V, respectively.

Performance evaluation and optimization of a perovskite solar cell-thermoelectric generator hybrid system

In order to improve the photo-to-electric energy conversion efficiency, a hybrid system is proposed by integrating a thermoelectric generator (TEG) with a perovskite solar cell (PSC). According to the derived formulas for the efficiency and power output of the hybrid system, three especial work states such as opened TEG, opened PSC, and PSC-TEG tandem cells are, respectively, discussed through numerical simulation. Further, we study the general work state, i.e., the PSC and the TEG independently drive their loads and are coupled with each other through energy balance equation. The matching loads 0.13Ωand 12.3Ωof the two subsystems and the optimum area 0.0324 m2 of the PSC can be chosen to obtain the maximum efficiency 0.216. Moreover, the perovskite layer’s optimum thickness 449.7nmis designed to obtain the overall maximum efficiency 0.229. For comparison, the hybrid system achieves improved overall energy efficiency by harnessing the waste heat produced in the PSC. The proposed model may provide some theoretical bases for the optimal design of practical PSC–TEG hybrid systems.

A New Simulation of Photovoltaic and Thermoelectric Generator Hybrid System with a Beam Splitter Cold and Hot Mirror for Low Intensity

In this study, the simulation of Photovoltaic (PV) and Thermoelectric Generator (TEG) hybrid was developed using a spectrum splitter. The simulation was carried out by using the AM1.5G solar spectrum as a standard for 1 Sun, with a variation of 0.05, 0.1, 0.25, 0.50, and 0.7 Suns. The light spectrum was concentrated by using a Fresnel lens and then transmitted to a spectrum splitter. Spectrum splitter that was used is a hot and cold mirror with dimensions of 50 × 50 mm, which is positioned at the angle of 45o from the Fresnel lens’s direction. Additionally, PV used is a type amorphous Silicon (a-Si) and TEG types of Bismuth telluride (Bi2Te3). The simulation result shows that by using a cold mirror, its maximum total power is better than a hot mirror. In addition, the Suns and temperature changes have a significant effect on the output power and efficiency of the hybrid. Particularly at 0.7 suns, 25 °C PV temperature, and 55 °C hot-side temperature of TEG, the power obtained was 0.096 W/m2, and the efficiency was 50.37% compared to the hot mirror, which is relatively lower, accounted for 0.094 W/m2 and 48.07%.

Introducing and investigation of a combined molten carbonate fuel cell, thermoelectric generator, linear fresnel solar reflector and power turbine combined heating and power process

Abstract In the present study, a combined heat and power process consists of molten carbonate fuel cell, thermoelectric generator, linear Fresnel solar reflector and power turbine is introduced and investigated from energy, exergy and thermodynamic points of view. Fuel cell produces electrical and thermal power. A part of waste heat from the fuel cell is sent to the thermoelectric generator to produce additional power and the remaining enters the environment. The solar field as a heat exchanger generates a part of the required thermal power of the proposed process. Linear Fresnel solar reflector with duty of 1728 kW is used too. Numerical modeling and thermodynamic analysis of the proposed system is done using MATLAB and HYSYS softwares, respectively. The results were discussed in two scenarios: (1) investigation of fuel cell and thermoelectric generator hybrid system and (2) investigation of whole combined heat and power process. Results indicate that the overall and electrical efficiencies of the proposed system are 64.93% and 31.57%, respectively. Also, in this process, 41728.8 kW of exergy is destroyed and the process total exergy efficiency is gained 0.12%. Finally sensitivity analysis of the fuel cell, turbines, solar system and thermoelectric generator against effective parameters is investigated.

Performance evaluation of a new design of concentrator photovoltaic and solar thermoelectric generator hybrid system

A new configuration of a photovoltaic module and a solar thermoelectric generator in a hybrid system integrated with a microchannel heat sink has been developed. The photovoltaic module and the solar thermoelectric generator sandwich the microchannel heat sink, as they are exposed to concentrated solar radiation. This newly developed hybrid system is compared to that with a conventional configuration in which an ordinary thermoelectric generator is attached directly to the rear surface of the concentrator photovoltaic module. To evaluate the performance of the new system in comparison to the conventional one, an all-inclusive three-dimensional thermo-fluid-thermoelectric model has been developed. This model is numerically simulated and is validated with both experimental and numerical results. The findings of this study show that the new system generates more output power and can be operated at higher concentration ratios with even lower average solar cell temperatures than the conventional system. In the new configuration, the average solar cell temperature is approximately 77 °C and the total electrical output power is approximately 3.2 kW/m2 at a solar concentration ratio of 20 suns. However, the maximum possible working concentration ratio for the conventional design is 10 suns, where the solar cell temperature approaches the highest tolerable temperature of approximately 90 °C. Moreover, the total electrical output power is approximately 1.2 kW/m2. Furthermore, it is found that at CR_PV = 20, the rate of the produced thermal energy is approximately 12 kW/m2, for the conventional design while the new design achieves 15, 22, and 30 kW/m2 for CR_STEG of 1, 10, and 20, respectively. These findings have greatly aided in identifying a new design that achieves the highest performance under concentrated solar irradiance.

Solar photovoltaic/thermal-thermoelectric generator performance review

Solar photovoltaic (PV) cells are currently limited by the temperature factor that causes the drop of efficiency when the module temperature rises. Many approaches were made to solve the issue so that the performance of the solar cell is improved including the integration of thermoelectric generator (TEG) hybrid. The objective of these improvements is to increase the temperature coefficient that will enhance the efficiency of the solar cells. Some approach may produce other benefits like thermal energy or building integration other than producing electrical energy. Common PV panels only utilize 15-30% of the irradiation received while the rest of it are reflected away or turned into heat waste. In this paper, the relationship of PV heat waste and PV performance relationship is explored. Photovoltaic/thermal-thermoelectric generator (PV/T-TEG) hybrid layouts were compared based on its performances including overall efficiency to identify solutions for this type of application. PV efficiency and losses due to thermal limits will demonstrate the issue as temperature increases. Solar cell that is available in the current market is simulated for its temperature prediction and heat dissipation. This will determine the potential application for a TEG hybrid. Previous conducted experiments and simulations show a 0.14% to 5.2% increment in electrical efficiency. The prediction model will agree with this range of finding. The current advancement in solar PV/T-TEG is compiled and the future approach that can be taken to solve the temperature limits will be discussed.

Performance prediction of hybrid thermoelectric generator with high accuracy using artificial neural networks

This paper presents the application of Artificial Neural Networks for the simulation of the performance parameters of a hybrid thermoelectric generator, using the artificial neural networks tool in the MATLAB software under various temperature, load and series condition. The simulated parameters (till an input heater temperature of about 250 °C) are compared with experimental results and the average error between the experimental approach and ANN based approach for all the parameter values is less than 3%. This low error value shows that the experiments need not be repeated for input temperatures above 250 °C which is quite complex. Hence, the effect of temperature gradient on the hybrid thermoelectric generator performance upto 350 °C of the hot side temperature with a single module and “N” no. of series connection have been estimated using ANN methodology. Experimental results suggest the necessity for ANN based approaches for hybrid TEG applications.

PERFORMANCE ASSESSMENT OF PHOSPHORIC ACID FUEL CELL - THERMOELECTRIC GENERATOR HYBRID SYSTEM WITH ECONOMIC ASPECT

Purpose of this paper is to evaluate phosphoric acid fuel cell (PAFC) - thermoelectric generator hybrid system with economic and thermoeconomic point of view. Firstly, basic equations of PAFC, thermoelectric generator and hybrid system are described. Secondly, basic performance parameters like power output, energy efficiency, exergy efficiency and exergy destruction rates are investigated. Finally, cost equations are set up to determine economic results of the considered system, in addition to that, these system are considered by using EXCEM analysis. According to results, the maximum total cost of the hybrid system is obtained j= 10900 am-2, exergy loss ratio to capital cost (ec) of the hybrid system increases dramatically after the point where is  j= 11000 am-2. Maximum power density, maximum energy efficiency and of the hybrid system are 8735.340 wm-2, 81.35% and 86.6% respectively.

Experimental investigation of a novel low concentrating photovoltaic/thermal–thermoelectric generator hybrid system

This paper presents and explores a novel low concentrating photovoltaic/thermal–thermoelectric generator (LCPV/T-TEG) hybrid system. Unlike the conventional hybrid photovoltaic-thermoelectric generator (PV/TEG), the system mainly consists of a compound parabolic concentrator, a double-glazing PV panel, a micro-channel heat pipe array, the TEG and the data acquisition and control system. The TEG is designed to be associated with the cold side of heat pipe array which acts as the cooling method of the LCPV/T system to improve PV efficiency instead of directly adhering to the backplane of the PV panel for practical applications. The outdoor experiment of the LCPV/T-TEG system was accomplished on the rooftop of a building in Beijing on a sunny day and the environmental conditions, the inlet and the outlet temperature, and output power of the LCPV/T and TEG were tested and analyzed. The daily average thermal efficiency is 45.0%, add to the daily average PV electrical efficiency 11.8% and daily average TEG electrical efficiency 0.23%, the daily average overall efficiency reaches 57.03%.Furthermore, the effects of the cooling flow on the system performance are also considered and the results show that the PV and TEG efficiencies both increase with the increasing of the flow.

A solar hybrid thermoelectric generator and distillation system

ABSTRACTA solar still of a single basin-slope coupled with a finned condensing chamber and installed thermoelectric modules at the bottom of the water basin has been presented in this paper. A mathematical model under steady state conditions has been introduced and improved to investigate the system performance. An increase of solar radiation and ambient temperature or a decrease in wind velocity affect positively the distillation rate, the still efficiency, and the system efficiency. Integrating a condenser and finned condenser increases the distillation rate of the proposed system. The results of the simulation have been verified by comparing them with published theoretical and experimental results, and the comparison shows very good agreement.