M. Yu. Shtern

Current state of thermoelectric material science and the search for new effective materials

The reasons for the recent increased interest in thermoelectricity are considered. Modern thermoelectric materials for practical use are reviewed. Criteria to be met by effective thermoelectric materials are analyzed. It is shown that the solid-solution method has almost completely exhausted itself. Directions in the search for new thermoelectric material classes are analyzed. The development of new bulk thermoelectric materials is connected with the search for and design of materials in which the peculiarities of the structure determine the strong scattering of phonons and decrease in thermal conductivity while maintaining high transport properties of charge carriers. The concept ‘phonon glass–electron crystal’ is of practical interest. Scientific and technological advances over the last decade give hope that more effective thermoelectric materials will be developed in the nearest future. One of the perspective applications of new thermoelectric materials is connected with the development of thermoelectric generators with segmented thermoelectric elements.

Prospects of creating efficient thermoelectric materials based on the achievements of nanotechnology

The elaboration of low-dimensional thermoelectric structures has been shown to allow an increase in the efficiency of thermoelectric materials by the end of the 20th century. The achievements in nanotechnology open up new opportunities in searching for prospective thermoelectric materials and structures. The physical aspects in the creation of low-dimensional thermoelectric structures have been reviewed. The capabilities of developing technologies for the synthesis of thermoelectric structures on the basis of superlattices, quantum wires, and quantum dots have been analyzed. The methods of fabrication and advances in the elaboration of nanocomposite thermoelectric materials have been discussed. The problems in the production of second-generation nanocomposites and their possible solutions have been considered. The methods for diagnosing low-dimensional thermoelectric structures are presented, as well.

Mo/Ni and Ni/Ta–W–N/Ni thin-film contact layers for (Bi,Sb)2Te3-based intermediate-temperature thermoelectric elements

We have examined the possibility of utilizing thin-film contact layers for producing reliable Ohmic contacts to proposed intermediate-temperature (Bi,Sb)2Te3-based thermoelectric materials with improved thermoelectric properties, which allow the working temperature range to be extended to 600 K. Three contact configurations have been produced by ion-plasma magnetron sputtering: a single Ni layer, Mo/Ni bilayer, and Ni/Ta–W–N/Ni three-layer system. It has been shown that reliable contacts can be produced using Mo/Ni and Ni/Ta–W–N/Ni layers, which prevent interdiffusion between the materials to be joined and ensure good adhesion to the thermoelectric element.

Thermoelectric systems for maintaining thermal conditions of computing machinery

Different variants of design solutions for thermoelectric systems (TESs) with various cooling powers used to maintain thermal conditions of computing machinery are proposed. Techniques for the calculation of thermoelectric blocks, confirmed by the results of investigations of the fabricated TES units, were developed.

Electron Thermostating Elements for Controlling Consumption of Heat Transfer Agent in the Heating Systems

Electron thermostating elements (ETE) mounted on the regulating radiator valves are developed. ETE are designed for the automatic controlling of the consumption of heat transfer agent in the heating systems by a special program. So, ETE are intended for the controlling of the temperature in the heated placements. ETE have autonomous power supply. Optimization of the working algorithm of ETE in conjunction with the high efficiency of the servomotor, and low level of power consumption of the electronic circuit allowed authors to increase the time of autonomous work of ETE. Proposed design solutions of ETE can be used also in different fields of science and technology for the automatic controlling of the consumption of liquid and gaseous agents.

Investigation and Calibration Methods of Precise Temperature Sensors for Controlling Heat Consumption

Authors developed precise temperature sensor with wireless interface (WTS). Methods of thermocompensation and individual calibration of WTS were developed in order to provide high requirements of the temperature measurement accuracy (0.02 °C). Measuring hardware-software complexes for the realization of this methods and carrying investigations were also developed.

Electronic thermometer with the data transfer by radiochannel

Precise electronic thermometer (ET) with the data transfer by radio channel is developed. Original patented design, circuitry and program solutions are employed in ET. Measuring hardware-software complexes for the investigation and calibration of ET are developed on the basis of the National Instruments equipment with using of LabView software.

Hardware and software equipment for the complex investigation of the wireless smart transducers

Hardware and software equipment for the complex investigation of the wireless smart transducers used in the systems for controlling thermodynamic parameters of energy carries was developed on the basis of National Instruments equipment. Stand tests and qualify transducers by the parameters of radio channel and power supply simulating real conditions of exploitation. Software on the development environment of LabView is developed for automation of investigation and testing processes. Stand can be operatively rearranged by appropriate adjustments, which allows testing following wireless standards: ZigBee, WiFi, WiMAX, Bluetooth, etc.

Intelligent system and electron components for controlling individual heat consumption

An intelligent system and its electron components are developed that implement an innovative method for measuring individual heat consumption. For the intelligent system and its electron components, original design-technological, circuit, hardware, and software solutions are proposed. The methods and mathematical models for evaluating individual heat consumption are developed and validated.

A heat transfer model of a horizontal ground heat exchanger

Ground-source heat pumps are gaining popularity in Eastern Europe, especially those which are using the horizontal ground heat exchanger (GHX). Due to the difficulty of accessing GHX after the installation, materials and the quality of the installation must satisfy the very high requirements. An inaccurate calculation of GHX can be the reason of a scarcity of heat power in a crucial moment. So far, there isn’t any appropriate mathematical description of the horizontal GHX which takes into account the mutual influence of GHX pipes on each other. To solve this problem we used the temperature wave approach. As a result, a mathematical model which describes the dependence of the heat transfer rate per unit length of the horizontal GHX pipe on the thermal properties of soil, operating time of GHX and the distance between pipes was obtained. Using this model, heat transfer rates per unit length of a horizontal GHX were plotted as functions of the distance between pipes and operating time. The modeling shows tha...