Goldsmid H. J. SYNTHETIC TRANSVERSE THERMOELEMENTS WITH A POROUS COMPONENT. University of New South Wales, Sydney, Australia. 2008, No. 1.- p.7-12.
It is possible to exploit the anisotropy of the Seebeck coefficient in a transverse thermoelement in which the flows of heat and electricity are perpendicular to one another. However, it does not seem that any single-phase material has properties that can be utilised effectively in this way. On the other hand, substantial transverse thermoelectric effects can be observed in a two-phase layered material. Previous studies have been devoted to composites made from a semiconductor and either a metal or semimetal. However, we show here that transverse thermoelements made from two semiconductors can have superior properties. One of the requirements is a substantial difference between the electrical and thermal conductivities of the two materials and it is shown that this can be achieved if one of them is porous or otherwise discontinuous. Our results should lead to transverse thermoelements with a figure of merit that is comparable with that of the best conventional thermocouples. Bearing in mind that infinite multistaging can be achieved by suitable shaping of a transverse thermoelement, it seems likely that a temperature depression of more than 100" will be reached using a transverse Peltier cooler.
Gurevich Yu. G. 1, Logvinov G. N.2. THERMOELECTRIC AND ELECTROTHERMIC HEATING AND COOLING IN SEMICONDUCTORS AND SEMICONDUCTOR STRUCTURES. (Review).1Departamento de Fisica, CINVESTAV-IPN, Apdo. Postal Distrito Federal, Mexico.
2Seccion de Posgrado e Investigacion dela Escuela Superior de Ingenieria Mecanica y Electrica del Instituto Politecnico Nacional, Distrito Federal, Mexico. 2008, No. 1.- p.13-30.
A comprehensive study of the mechanisms of heating and cooling originated by the electrical current in semiconductor devices is reported. The authors study the Peltier, Joule and Thomson phenomena self-consistently in approximation of a weak electric current taking into account temperature dependence of all kinetic coefficients. Calculations show that contributions of all of them to the temperature distribution are commensurable. A new formulation and interpretation of the Thomson effect are offered. Along with new results, a certain attention is paid to some questions of nonequilibrium thermodynamics of thermoelectric and electrothermic phenomena, which demand some definition.
Prybyla A. V. SPIRAL RECTANGULAR ANISOTROPIC THERMOELEMENT IN COOLING MODE. Institute of Thermoelectricity, Chernivtsi, Ukraine. 2008, No. 1.- p.13-30.
The distribution of temperature field inside a spiral rectangular anisotropic thermoelement (SRAT) is obtained and the influence of various factors thereon is determined. The SRAT cooling power and coefficient of performance are calculated. The volt-watt sensitivity of SRAT-based heat flow sensor is increased.
Tosawat Seetawan. ELECTRICAL RESISTIVITY AND THERMOELECTRIC POWER OF POLYCRYSTALLINE Na0.75CoO2. Department of Physics, Faculty of Science and Technology, Sakon Nakhon University, Thailand. 2008, p; No. 1.- p.37-41.
The electrical resistivity and thermoelectric power of g -Na0.5CoO2 polycrystalline sample have been analyzed depending on the direction. Measurements were made in two directions, namely, parallel and perpendicular to compaction axis of samples cut as pellets. The electrical resistivity and thermoelectric power of g-Na0.5CoO2 polycrystalline sample parallel and perpendicular to compaction axis increase with temperature, like in a transition metal oxide, have close low values at low temperature and different values at high temperature.
Gunko G. S., Kopyl A. I., Pavlovych I. I., Feychuk P. I.,. Scherbak L. P. BULK DEFECTS IN VAPOUR-GROWN CRYSTALS OF A4B6 AND A2B6 SOLID SOLUTIONS.
Institute of Thermoelectricity, Chernivtsi, Ukraine. 2008, No. 1.- p. 42-46.
Factors governing the development and morphology of the bulk defects in single crystals: inclusions, microvoids, L-pores, secondary-phase separations on the surface have been studied. The dependences of growth processes parameters on structural properties of single crystals have been established. Relationship between the microvoid density and morphology of small angle boundaries and grain boundaries in crystal has been determined. Based on the above studies, recommendations for the optimization of conditions for vapour-growth of structurally perfect A4B6, A2B6 crystals, whereby said bulk defects are absent and dislocation density is Ndd < 104 cm-2 have been elaborated.
Razinkov V. V., Lelek V. Yu. PROPERTIES OF ANTI-DIFFUSION NICKEL LAYERS DEPOSITED ON BISMUTH TELLURIDE BY ELECTRIC-ARC METHOD. Institute of Thermoelectricity, Chernivtsi, Ukraine. 2008, No. 1.- p. 47-52.
Process peculiarities of anti-diffusion nickel layers deposition onto bismuth telluride based ternary compounds by electric-arc method have been studied. Design of electric-arc metallizer has been improved and optimal conditions for preparation of 80 100 µm thick nickel layers have been determined. For said layers, the values of contact resistance and electric resistivity have been obtained, the adhesion characteristics have been studied.
Nimchuk V. V.,Zaparov S. F., Satygo A. V. HIGH-PRODUCTIVITY MACHINE FOR CUTTING THERMOELECTRIC MATERIALS.
Institute of Thermoelectricity, Chernivtsi, Ukraine. 2008, No. 1.- p. 53-58.
This paper studies processing modes of Bi2Te3 based materials. The depth of damaged surface layers of Bi2Te3 based materials cut by different methods is established. The productivity and cost of cutting Bi2Te3 based thermoelectric materials by Altec 13005 M wire cutting machine is determined.
Saqr Kh. M., Mansour M. Kh., Musa M. N. THERMAL DESIGN OF AUTOMOBILE EXHAUST-BASED THERMOELECTRIC GENERATORS: OBJECTIVES AND CHALLENGES
Department of Thermo-Fluids, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, Malaysia. 2008, No. 1.- p. 59-66.
The potential for thermoelectric power generation via waste heat recovery onboard automobiles to displace alternators and/or provide additional charging to a vehicle battery pack has increased with recent advances in thermoelectric materials processing. In gasoline fueled vehicles (GFVs), about 40% of the fuel energy is wasted in the exhaust heat [1], while a smaller amount of energy (30%) is rejected through the engine coolant. Therefore, exhaust-based thermoelectric generators (ETEG) have been in focus for GFVs applications since the late 1980s. Conversion efficiency of modern thermoelectric materials has increased more than three times in the last two decades [2]; however, the disputes in thermal design of ETEG systems kept their overall efficiency at limited insufficient values. There are many challenges in thermal design of ETEG systems, represented in increasing the efficiency of the heat exchangers (hot box and cold plate), maintaining sufficient temperature difference across the TEMs during different operating conditions, and reducing thermal losses through the system as a whole. This paper is focused on reviewing the main aspects of the thermal design of ETEG systems through the different investigations performed over the past fifteen years. This paper is organized as follows: the construction of a typical ETEG is first described. The heat balance and efficiency of ETEG are then discussed. The third section of this paper emphasizes the main objectives and challenges for designing efficient ETEG systems. Finally, a review of ETEG research activities through the last fifteen years is presented to focus on the methods used by research community to address such challenges.
Anatychuk L. I., Lys'ko V. V. HIGH-PRECISION METHOD FOR MEASURING ELECTRIC CONDUCTIVITY OF THERMOELECTRIC MATERIAL RODS.
Institute of Thermoelectricity, Chernivtsi, Ukraine. 2008, No. 1.- p. 67-72.
High-precision method for measuring electric conductivity of thermoelectric material rods that eliminates measurement errors due to current density inhomogeneity in a rod has been elaborated. Computer model of electric conductivity measurement that yields electric potential and temperature distributions in a rod and permits their use to find measurement errors has been created.
Anatychuk L. I.,Mikhailovsky V. Ya. TWO-SECTIONAL GAS-FUELED THERMOELECTRIC GENERATOR. Institute of Thermoelectricity, Chernivtsi, Ukraine. 2008, No. 1.- p. 73-84.
The results of research on two-sectional gas-fueled thermogenerator are represented. Analytical model of the generator with forced cooling by heating fluid is proposed, optimization method is described, results of calculating the basic characteristics of sectional generator are represented.