Thermoelectric (TE) technology is regarded as alternative and environmentally friendly technology for harvesting and recovering heat which is directly converted into electrical energy using thermoelectric generators (TEG). Conversely, Peltier coolers and heaters are utilized to convert electrical energy into heat energy for cooling and heating purposes The main challenge lying behind the TE technology is the low efficiency of these devices mainly due to low figure of merit (ZT) of the materials used in making them as well as improper setting of the TE systems. The objective of this work is to carry out a comprehensive review of TE technology encompassing the materials, applications, modelling techniques and performance improvement. The paper has covered a wide range of topics related to TE technology subject area including the output power conditioning techniques. The review reveals some important critical aspects regarding TE device application and performance improvement. It is observed that the intensified research into TE technology has led to an outstanding increase in ZT, rendering the use TE devices in diversified application a reality. Not only does the TE material research and TE device geometrical adjustment contributed to TE device performance improvement, but also the use of advanced TE mathematical models which have facilitated appropriate segmentation TE modules using different materials and design of integrated TE devices. TE devices are observed to have booming applications in cooling, heating, electric power generation as well as hybrid applications. With the generation of electric energy using TEG, not only does the waste heat provide heat source but also other energy sources like solar, geothermal, biomass, infra-red radiation have gained increased utilization in TE based systems. However, the main challenge remains in striking the balance between the conflicting parameters; ZT and power factor, when designing and optimizing advanced TE materials. Hence more research is necessary to overcome this and other challenge so that the performance TE device can be improved further.

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A comprehensive review of thermoelectric technology: materials, applications, modelling and performance improvement

The pulsed laser deposition is a new technique for the growth of thin films,which has been attended generally by people recently The physical principle, unique characteristics and the proceeding of the study were introduced briefly In addation, the result of the PtSi nanometer thin film based on silicon prepared by the pulsed laser deposition was describedPULS

Pulsed laser deposition of thin films

Thermoelectric cooler and thermoelectric generator devices: A review of present and potential applications, modeling and materials

The need for energy-efficient and environmentally friendly refrigeration, heat pumping, air conditioning, and thermal energy harvesting systems is currently more urgent than ever. Magnetocaloric energy conversion is among the best available alternatives for achieving these technological goals and has been the subject of substantial basic and applied research over the last two decades. The subject is strongly interdisciplinary, requiring proper understanding and efficient integration of knowledge in different specialized fields. This review article presents a historical and up-to-date account of the energy-related applications of magnetocaloric materials and information about their processing and magnetic fields, thermodynamics, heat transfer, and other relevant characteristics. The article also discusses the conceptual design of magnetocaloric refrigeration and power generation systems and some guidelines for future research in the field.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/aenm.201903741

Energy Applications of Magnetocaloric Materials

Alternative renewable energy sources are immensely important in view of the increase in worldwide energy needs and environmental effects. The thermoelectric (TE) technology is being seen as the perfect solution for both issues due to its ability to convert heat directly into electricity without CO2 emission. However, the application of TE materials for commercial devices is still limited due to their low conversion efficiency of ~10–15%. Currently the improvement of TE efficiency is challenging due to the relationship among physical properties, i.e., electrical conductivity, thermal conductivity and Seebeck coefficient which often counter each other and are restricted by the carrier concentrations. Fortunately, nanostructures have been shown to be able to disconnect the link among these physical properties to enhance the conversion efficiency of materials. Thus, the purpose of this review paper is to present the different nanostructured approaches for enhancing the TE properties of materials. The various techniques have been widely used to synthesize the bulk nanostructure and low dimensional systems were also described. A discussion on potential heat resources for the TE conversion, as well as the recent progress in TE is provided in terms of material, process and technology. Nanostructured skutterudites, half - Heusler, oxides and Si-Ge binary system were focused in this review paper due to the fact that the TE materials are among the best candidates for high-temperature applications. We also included our estimation in output electrical power of thermoelectric generation (TEG) for these type TE materials. Besides that, some innovations for the development of TE materials were mentioned. In addition, we also discussed the estimation of the TE cost to shed some light on commercializing considerations. We concluded that the high cost of the heat exchanger and ceramic substrate system components proved to be barriers in reducing the cost of TEG.

A review on nanostructures of high-temperature thermoelectric materials for waste heat recovery

This paper deals with a review of the main research aspects concerning the formulation of the parameters indicating the characteristics and performance of thermoelectric cooling devices, with particular reference to a number of recent publications. The specific aspects addressed include some practical considerations referring to the thermoelectric figure of merit, the characterization of the cooling capacity, and the assessment of the coefficient of performance ( COP ). The contribution of this paper starts by categorizing the topics addressed by recent review papers, showing that these reviews generally had a wide focus and provided little specific details on thermoelectric cooling parameters and performance. Then, the dimensionless thermoelectric figure of merit is addressed by focusing on its conventional and modified definitions and indicating the values obtained for different thermoelectric cooling materials. Furthermore, the expressions of the cooling capacity for single-stage and multi-stage thermoelectric coolers are reviewed. Concerning the COP , its dedicated expressions are constructed starting from the classical formulation and introducing additional factors or modifications in order to take into account the Thomson effect, the dependence on temperature of the thermoelectric materials, and the effects of the electrical contact resistance, thermal resistance, thermoelement length and current. Finally, on the basis of the indications taken from the literature, further considerations are included on the COP values found in thermoelectric cooling applications, as well as on how to obtain COP improvements.

A review on thermoelectric cooling parameters and performance

The thermoelectric systems have attracted renewed interest as concerns with the efficient use of energy resources, and the minimization of environmental damage, have become important current issues. There has been he recognition that thermoelectric devices could play a role in generating electricity from waste heat, enabling cooling via refrigerators with no moving parts, and many other more specialized applications. This paper presents of numerical simulation for several the thermoelectric materials. Numerical simulation is carried out by using a finite element package ANSYS.

http://www.wseas.us/e-library/conferences/2010/Corfu/SYSTEMS/SYSTEMS2-48.pdf

Numerical simulation of thermoelectric system

The complexity of the icing/thawing processes, in case of interference of the temperature fields, generated by multiple pipes, is very difficult to be reproduced in the established conditions within the laboratory. The data processing can be approached by numerical methods in order to solve the complex problem of the heat transfer in mediums with mobile boundaries and the phase transition. Such major preoccupations are often met to the aquifer soil excavation consolidated by water freezing from soil, namely, to subway construction, construction of the water supply networks, sewer systems, etc. Based on the real experimental data, the numerical computation was made by means of the application entitled ADITP, which was also presented in other papers, where some methods like: linear interpolation, Spline interpolation and Lagrange interpolation were studied. These approximation methods were chosen in order to generate the simple or complex analytical functions, which have small errors of approximation. In this paper, the authors present the obtained results using a better approximation, in this case being polynomial regression, which represents a very good evaluation of all processes. Our software application analyses the temperature fields which are generated for two structures of phenomena using the data acquisitioned by an acquisition board and for the first time an approach in the Visual C# program.

http://www.wseas.us/e-library/conferences/2008/rhodes/istasc/istasc11.pdf

Numerical investigation by means of polynomial regression method for determining the temperature fields in a medium with phase transition

Physical phenomena of electromagnetic nature are described by Maxwell’s equations from the mathematical point of view These are differential equations with the given boundary conditions By means of them, the exact solution of the problem is obtained In this way, the value of function or functions in any point of the studied range is calculated This represents the analytical way for solving the problems

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Finite Element Analysis of Stationary Magnetic Field

Electrical distribution system reconfiguration is frequently addressed as a multi-objective problem, typically taking into account the system losses together with other objectives, among which reliability indicators are widely used. In the multi-objective context, Pareto front analysis enables the operator handling conflicting and even non-commensurable objectives without needing the use of additional hypotheses or weights. This paper provides advances on the application of Pareto front analysis to multi-objective distribution network reconfiguration. Starting from previous results in which genetic algorithms were effectively adopted to find the best-known Pareto front, a version of the multi-objective binary particle swarm optimization (MOBPSO) customized for distribution network reconfiguration has been developed by exploiting the internal ranking of the solutions (based on a multi-criteria decision making method in the selection of the local best) and the network topology. Furthermore, the Pareto front mismatch metric (already used by the authors to compare different methods for small networks for which the complete Pareto front can be calculated) has been generalized to be used with large systems for which only the best-known Pareto front is found. Applications to a test network and to a real urban distribution network are discussed, showing the consistent superiority of the customized MOBPSO version with respect to the application of genetic algorithms and of a more classical version of the particle swarm optimization method.

https://link.springer.com/content/pdf/10.1007%2Fs40903-016-0065-6.pdf

Elena Otilia Virjoghe

Papers

A review on thermoelectric cooling parameters and performance

Numerical simulation of thermoelectric system

Numerical investigation by means of polynomial regression method for determining the temperature fields in a medium with phase transition

Finite Element Analysis of Stationary Magnetic Field

Multi-Objective Distribution Network Reconfiguration Based on Pareto Front Ranking