Thermoelectric Coupling Research Articles

Design optimization method of heating and cooling full cycle storage air conditioning in integrated energy system

Heating and cooling storage air conditioning is an important part of the integrated energy system, which can play an important role in the flexible conversion of thermoelectric coupling systems. Because storage air conditioning involves the dynamic characteristics of power supply on the source side and cold and heat demand on the load side, system capacity allocation is a problem of technical and economic optimization. This paper breaks through the traditional design method based on the hourly load distribution law of typical design days and proposes a performance-oriented design method for the bidirectional full-cycle dimension storage air conditioning system based on the system’s annual operation performance, which can take into account the hourly dynamic load distribution law of every day in the full heating season and the full cooling season coupled with the bidirectional demand of cold and heat loads. A more scientific and reasonable capacity configuration scheme for the storage air conditioning system is obtained. The design is presented with a concrete case.

Thermoelectric coupling effect in BNT-BZT-xGaN pyroelectric ceramics for low-grade temperature-driven energy harvesting

Pyroelectric energy harvesting has received increasing attention due to its ability to convert low-grade waste heat into electricity. However, the low output energy density driven by low-grade temperature limits its practical applications. Here, we show a high-performance hybrid BNT-BZT-xGaN thermal energy harvesting system with environmentally friendly lead-free BNT-BZT pyroelectric matrix and high thermal conductivity GaN as dopant. The theoretical analysis of BNT-BZT and BNT-BZT-xGaN with x = 0.1 wt% suggests that the introduction of GaN facilitates the resonance vibration between Ga and Ti, O atoms, which not only contributes to the enhancement of the lattice heat conduction, but also improves the vibration of TiO6 octahedra, resulting in simultaneous improvement of thermal conductivity and pyroelectric coefficient. Therefore, a thermoelectric coupling enhanced energy harvesting density of 80 μJ cm−3 has been achieved in BNT-BZT-xGaN ceramics with x = 0.1 wt% driven by a temperature variation of 2 oC, at the optical load resistance of 600 MΩ.

Plasma actuating modified multiwalled carbon nanotubes (MWCNTs) to strengthen interface of MWCNTs/Polylactic acid composites by constructing interlaminar stress-transfer bridge

A new stepwise hybrid manufacturing (HM) strategy based on plasma-actuating carbon nanotubes is proposed to enhance the interfacial properties of modified multiwalled carbon nanotubes (MMWCNTs)/polylactic acid (PLA) nanocomposites. Although the thermoelectric coupling field caused by plasma can partially destroy the MMWCNTs, it does not affect the functional groups on the MMWCNTs. Meanwhile, under the actuation of the thermoelectric coupling field, the MMWCNTs can react with the PLA matrix to form chemical bonds with a strong intermolecular force, thus forming a stress-transfer bridge between adjacent substrate layers and fully exerting the nanoscale “rib-reinforcing” effect of MMWCNTs to enhance the interlaminar interface. In addition, the proposed HM method can avoid the weakening of the interlaminar interface caused by the orientation of the nozzle and the restriction of MMWCNTs on the matrix activity indicated in conventional manufacturing methods. Experimental and molecular dynamics simulation results confirm the effectiveness of the proposed method in promoting the interfacial properties of MMWCNTs/PLA nanocomposites.

Optimize configuration of multi-energy storage system in a standalone microgrid

Aiming at the integrated energy microgrid, an important part of the energy internet, this paper constructs a multi-energy storage system optimization configuration model of the integrated energy microgrid in an independent mode, and proposes a configuration method that includes the rated power and capacity of the storage system and the heat storage system. The storage system model includes the estimation of battery life during heating and non-heating periods. The model takes economy as the index, and considers the relevant constraints of thermoelectric coupling of thermoelectric units, including thermal and electrical balance, unit climb, energy storage system and self-sufficiency probability, etc., and uses a The bacterial colony chemotaxis (BCC) algorithm model based on unit output and energy storage system power distribution strategy to solve the problem. The operation characteristics of cogeneration units equipped with energy storage system are discussed. The results show that the proposed multi-energy storage system configuration method has significant economic and environmental benefits in both heating and non-heating periods, and promotes the uptake of wind power.

Three-dimensional numerical study of the behavior of thermoelectric and mechanical coupling during spark plasma sintering of a polycrystalline material

Three-dimensional numerical study of the behavior of thermoelectric and mechanical coupling during spark plasma sintering of a polycrystalline material

Investigation of neutronic and thermal–electric coupling phenomenon in a 100 kWe-level nuclear silent heat pipe-cooled reactor

Heat pipe-cooled reactors are attractive because of their compact structure, high power capacity and reliability, and inherent safety features. These reactors are distinguished by the use of high-temperature heat pipes that directly bridge the reactor core and energy conversion devices, thus creating a tightly knit modular system. However, comprehensive coupled analysis of these reactors remains challenging because of the intricate multiphysics interactions involved. To address this, the neutronic and thermoelectric coupled phenomena of heat pipe-cooled reactors are investigated in this study. Models are introduced for the point reactor kinetics, core heat transfer, channel heat transfer, two-phase two-dimensional heat pipes, thermoelectric coupling, and cold plates. The channel heat transfer is refined in a 100 kWe-level nuclear silent heat pipe-cooled reactor and a model for the three-dimensional heat transfer process in its thermoelectric matrix established, which effectively resolves the calculation distortions of the lumped model. The maximum deviation between the calculation results from the proposed model and the verification data for a full-system coupled computation is less than 10 K. The core temperature difference from the three-dimensional model is five times that of the lumped model with a maximum average fuel temperature difference of 225.7 K. The maximum and average thermoelectric conversion efficiencies are 15.56 % and 14.43 %, respectively. The failures of one, five, and nine heat pipes are analysed. The failure of a single heat pipe has negligible effects with a peak fuel temperature surge of only 121 K. In contrast, a failure involving nine heat pipes leads to a peak fuel temperature spike of 778 K and a 47.1 % increase in the maximum heat transfer power, marking a critical operational threshold. It is therefore imperative to consider the safety margin in the potential failure of multiple central heat pipes during the preliminary design stages.

Lithium ion batteries participating in frequency regulation for power grid under the thermoelectric coupling degradation mechanisms

Lithium-ion batteries (LIBs) play an important role for the global net-zero emission trend. They are suitable for the power interaction with the power grid with high penetration renewable energy. However, the detail evolution of the LIBs participating in frequency regulation (FR) service at low temperature is critical for the all-climate application, especially the capacity decay and the related economic loss. This study reveals that the primary degradation mechanisms for FR operation at low temperature include lithium plating of anode and lattice distortion of cathode. Surprisingly, FR with appropriate parameters for batteries at low temperature does not introduce additional capacity decay due to the great temperature rise brought about and the optimized interfacial mass transfer. This study then analyses the economy of electric vehicles (EVs) participating in FR service, which is called vehicle-to-grid (V2G). A better temperature control can improve the profit of 35.88 $/kW. An appropriate capability is also vital to improve the profit of FR service. Moreover, suitable FR conditions for LIBs can even bring a certain degree of capacity improvement at low temperature. This work guides the design criteria of non-destructive LIB interaction for future grid.

Real-time Monitoring Method of Insulation Status of Photoelectric Composite Submarine Cable based on Thermoelectric Coupling

The existing approach for monitoring the insulation state of photoelectric composite submarine cables primarily relies on detecting the current of the cable protection layer. However, this conventional method suffers from limited monitoring accuracy due to the absence of parameter identification processing for the cable. As a result, there is a need to improve the monitoring methodology by incorporating robust parameter identification techniques to enhance the accuracy of insulation state evaluation. In this regard, a real-time monitoring method based on thermoelectric coupling is proposed to monitor the insulation status of the photoelectric composite submarine cable. By constructing an equivalent composite circuit model and a thermodynamic function, a thermoelectric coupling model is constructed and used to identify the parameters of the submarine cable; by extracting the frequency extremes in the spectral values of the submarine cable current signal, an equivalent insulation characteristic function is constructed to realize the determination of the insulation state. The proposed method is verified for the insulation state monitoring effect in the experiment. The experimental results show that when the proposed method is used to monitor the insulation state of the photoelectric composite submarine cable, the calculated partial discharge quantity has a small error, and the monitoring accuracy is high.

Research on Park Energy System Based on Grid Connection of Renewable Energy Power Generation

With the maximum consumption of renewable energy, the minimum emission of pollutants and the minimum comprehensive investment cost as the optimization objectives, the operation model of the park’s energy system considering the thermal power balance constraint, natural gas balance constraint and power grid power constraint was proposed, and the scenic power generation and electricity equipment of the park were studied. By comparing different operation scenarios, the influence of adding different equipment on the operation optimization of the whole park under the thermoelectric coupling is comprehensively analyzed. The balance curve of equipment output and related energy use is analyzed on a yearly cycle, indicating that the power supply grid of the park based on the thermoelectric coupling has great reliability and effectiveness in the consumption of renewable energy, and its economy is also significantly improved.

Construction and simulation analysis of lithium‐ion batteries thermoelectric coupling model based on digital twin

AbstractWith the rapid development of energy storage technology, it is significant to evaluate the operating status of lithium‐ion batteries efficiently and accurately, so as to ensure their safe operation and reduce the probability of accidents. For the problems of long simulation time and low accuracy in existing models, this paper proposes a construction method of lithium‐ion batteries thermoelectric coupling model based on digital twin. First, the digital twin structure system of lithium‐ion batteries is proposed. Second, considering the coupling effects of the thermodynamic model and the equivalent circuit model, the thermoelectric coupling model is constructed based on the digital twin platform ANSYS TwinBuilder. The thermodynamic model is reduced in order and the simulation time is reduced to second level, which improves the simulation efficiency and meets the real time simulation requirements of the digital twin. Furthermore, considering that the operating parameters of lithium‐ion batteries are variable, the parameters of the equivalent circuit model are identified online based on the variable forgetting factor recursive least squares algorithm. It updates parameters of the model and improves the simulation accuracy. Finally, the efficiency and accuracy of the model are verified through simulation analysis.

Collaborative configuration and optimal operation of cogeneration system based on phase change heat storage

Given the low efficiency of heating and power supply caused by the low temperature in the Northeast during the heating process of the solar heat pump, the article first adds phase change hot storage device based on time-sharing control based on the traditional PVT collector — heat pump, and constructs a flexible thermoelectric coupling multi-energy system by shifting the peak and filling the valley; Secondly, based on TRNSYS software, the simulation model of PVT collector-heat pump-phase change heat storage-electrical coupling combined supply system is built. By comparing with the heat storage system using an ordinary heat storage tank, the results show that the phase change water tank system can significantly improve the system performance. Finally, Hooke-Jeeves is used to optimize the inclination angle, area, volume of the tank, and heating capacity of the air source heat pump of the PVT collector of the thermal-electric coupling system, to increase the system’s one-year operation.

Experimental study on thermoelectric effect pattern analysis and novel thermoelectric coupling model of BIPV facade system

Electrical and thermal energy are the primary forms of useful energy generated by building integrated photovoltaic façade (BIPV façade) systems, while their interaction during operation remains unclear. This study aims to analyze the energy generation patterns and quantify the impact of thermoelectric coupling in BIPV façade systems. Through long-term outdoor experiment conducted on an actual BIPV façade system, the underlying regularity of thermoelectric coupling was discovered by analyzing the electrical and thermal characteristics. Results showed that under same solar radiation, enlarged air channel spacing led to a 53.22% increase in air channel heat and a 12.27% increase in mean thermal efficiency. Additionally, the heat proportion increased by approximately 15%, while the electricity proportion decreased by 15%. Furthermore, the mathematical relationships of the thermoelectric association factors were determined to quantify the observed thermoelectric generation patterns. A novel thermoelectric coupling model was established and validated with errors below 6.21% for accurate estimation of thermoelectric performance under actual operating conditions. Results emphasized both thermal and electrical energy generation of BIPV façade, which offers a new perspective on the comprehensive utilization of thermoelectric association in BIPV façade design and building applications, opening avenues for enhanced energy efficiency in renewable energy systems.

A Short Review of Through-Silicon via (TSV) Interconnects: Metrology and Analysis

This review investigates the measurement methods employed to assess the geometry and electrical properties of through-silicon vias (TSVs) and examines the reliability issues associated with TSVs in 3D integrated circuits (ICs). Presently, measurements of TSVs primarily focus on their geometry, filling defects, and the integrity of the insulating dielectric liner. Non-destructive measurement techniques for TSV contours and copper fillings have emerged as a significant area of research. This review discusses the non-destructive measurement of contours using high-frequency signal analysis methods, which aid in determining the stress distribution and reliability risks of TSVs. Additionally, a non-destructive thermal detection method is presented for identifying copper fillings in TSVs. This method exploits the distinct external characteristics exhibited by intact and defective TSVs under thermoelectric coupling excitation. The reliability risks associated with TSVs in service primarily arise from copper contamination, thermal fields in 3D-ICs, stress fields, noise coupling between TSVs, and the interactions among multiple physical fields. These reliability risks impose stringent requirements on the design of 3D-ICs featuring TSVs. It is necessary to electrically characterize the influence of copper contamination resulting from the TSV filling process on the reliability of 3D-ICs over time. Furthermore, the assessment of stress distribution in TSVs necessitates a combination of micro-Raman spectroscopy and finite element simulations. To mitigate cross-coupling effects between TSVs, the insertion of a shield between them is proposed. For efficient optimization of shield placement at the chip level, the geometric model of TSV cross-coupling requires continuous refinement for finite element calculations. Numerical simulations based on finite element methods, artificial intelligence, and machine learning have been applied in this field. Nonetheless, comprehensive design tools and methods in this domain are still lacking. Moreover, the increasing integration of 3D-ICs poses challenges to the manufacturing process of TSVs.

Li-ion battery charging strategy based on multi-state joint estimation model

This paper proposes a fast-charging strategy for lithium-ion batteries based on an intelligent optimization algorithm with multi-physics constraints. First, a thermoelectric coupling model and a battery degradation model have been established. Then an improved particle swarm optimization (PSO) is used to calculate the optimal charging strategy under different weighting factors. Finally, the Pareto boundary is drawn according to the optimization objective, and two charging strategies with different optimization objectives are developed. By comparing in different benchmark functions, the So-improved PSO proposed in this paper improves the convergence of the algorithm compared to the traditional PSO algorithm without increasing the computation time. The simulation results show that the multistage constant-current (MCC) charging strategy proposed in this paper can adjust the magnitude and order of charging current according to the change of weights, and reducing the loss of capacity and energy by only 0.017 % and 35.1 % while improving the charging speed by 24.9 % compared with the constant current-constant voltage (CCCV) charging strategy of 2C. Compared with the traditional CCCV charging strategy, the charging method proposed in this paper can have a broad application prospect.

Multi-objective Collaborative Planning Method for Micro-energy Systems Considering Thermoelectric Coupling Clusters

As the continuous development of integrated energy system and distributed power supply, operation economy and regional energy Internet reliability, especially micro-energy system, are increasing. Therefore, it is necessary to build multi-energy complementary micro-energy system, innovate energy supply mode, realize collaborative and efficient utilization among multi-energy systems, improve energy utilization efficiency and absorb renewable energy. In this paper, the decision model of distribution network planning scheme including distributed generator supply is established from four aspects: investment and operation cost, extra reserve capacity, energy conservation, reliability cost. The decision model involves a lot of parameter calculation and selection judgment, so after the decision goal is determined, an decision framework based on DS-MAS is established, that is, parameters are automatically calculated and selected based on different scenarios. Model validity is proved via a practical decision project.

Thermoelectric coupling effect of secondary injection on gasoline fuel spray and mixing of a free vibration combustion alternator

This article focuses an unconventional energy transducer called free vibration combustion alternator that directly utilizes mechanical vibration to convert fuel combustion heat energy into electrical energy, while studying the impact of secondary injection strategy on fuel spray and mixing in a free vibration combustion alternator. A thermoelectric-mechanical coupling model is developed to take into account the interaction effect between vibration, generation, combustion on fuel spray and mixing in free vibration combustion alternator. Meanwhile, an algorithm method is proposed to iterate the calculation results of vibration and combustion for simulating the effect of the secondary injection strategy on the mixture formation characteristic. The results indicate that the fluctuation of secondary injection ratio affects the free vibration combustion alternator vibration, and then changes the compression ratio and the initial conditions for fuel injection and mixture formation. The free vibration combustion alternator operating in secondary injection proportion of 9:1 condition shows equivalent speed of 2061 r/min, compression ratio of 8.75, fuel evaporation rate of 91.4%, mixing uniformity index of 86.4%, and they are adjusted to 1855 r/min, 7.96, 99.9%, 32.2% respectively when the secondary injection proportion is 1:9. Moreover, a larger secondary injection proportion causes stronger turbulent motion, significantly improving the mixing quality.

IGBT reliability analysis of photovoltaic inverter with reactive power output capability

When the PV power supply participates in reactive power regulation of distribution network, its output reactive power will affect the reliability of IGBT in the PV inverter. Aiming at this problem, this paper first qualitatively analyzed the influence of photovoltaic power supply participating in reactive power regulation of distribution network on the reliability of photovoltaic power supply. Then, a quantitative evaluation method of IGBT reliability based on data-driven was proposed. This method uses LightGBM machine learning model to replace the traditional thermoelectric coupling model, which effectively improves the calculation efficiency of IGBT junction temperature and reduces the dependence of IGBT reliability evaluation results on IGBT model parameters. Through this method, the reliability of core power electronic devices in photovoltaic inverters is quantitatively evaluated according to active power, reactive power, solar irradiance and ambient temperature. Finally, based on the IEEE 33 node distribution system, the reliability of IGBT in PV inverters participating in reactive power regulation of the distribution network was evaluated.

IGBT Thermal Model-Based Predictive Energy Management Strategy for Plug-In Hybrid Electric Vehicles Using Game Theory

Energy management strategy (EMS) of plug-in hybrid electric vehicle (PHEV) can coordinate the efficient coupling operation between multiple power sources, which is of great significance to the improvement of fuel economy and transmission efficiency. During the actual operation, EMS needs the electric drive system operate frequently to achieve excellent vehicle performance. In this case, the temperature of insulated gate bipolar transistor (IGBT) module inevitably increases and the thermal-mechanical stress caused by temperature fluctuation will lead to failure. To solve the above problems, a model predictive control (MPC)-based EMS considering IGBT temperature is proposed. Firstly, Markov chain-based driver model is built for the prediction of future vehicle speed. Secondly, according to the thermoelectric coupling model description of the IGBT module, a predictive energy management framework is constructed with fuel economy and IGBT temperature indexes as objective functions. Then, under the MPC framework, a non-cooperative game model with engine and IGBT as participants is established, and Nash equilibrium is taken as the solution. Finally, the simulation results indicate that the proposed strategy not only improves the fuel economy by 13.88% and 13.48% compared with the rule-based strategy under two driving conditions, but also effectively reduces the temperature of IGBT.

Performance evaluation of lithium battery pack based on MATLAB simulation with lumped parameter thermal model

AbstractThe capacity of lithium batteries varies under different temperature conditions. However, many studies still neglect the influence of temperature on battery capacity. Besides, some studies only considered the combination of the heat and electricity of the battery monomer and failed to study the performance of the battery pack in groups. This paper investigates a new method for dynamic situations that takes the influence of temperature on battery capacity into consideration. After acquiring the parameter through experiment, we can substitute the performance parameters into the thermoelectric coupling model and use MATLAB to realize the iterative calculation of thermoelectric coupling. By combining the grouping mode with the model, we can simulate the thermodynamic and electrical properties of the battery cell in the pack. The novelty is evident because the paper focused on the battery pack instead of a single cell and the lumped parameter thermal model is adopted. Besides, the method proposed in this paper considered the influence of temperature on battery capacity. The program of calculation process can be solidified on the vehicle system. After the simulation, we can get the available capacity of the battery pack at different initial temperatures, with different grouping modes and different inconsistency of parameters. The results predicted by MATLAB model are compared with the results of MATLAB‐FLUENT thermoelectric coupling simulation. The result reflects that the prediction by the MATLAB model about the available capacity, temperature, and residual electricity is of good precision.

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.