RECENT ADVANCES IN THERMOELECTRIC POWER GENERATION: STAND-ALONE AND GRID-CONNECTED APPLICATIONS

MOLINA M.G.; JUANICÓ L.E.

Advances in Energy Research. Volume 8.

NOVA SCIENCE PUBLISHERS Inc.

Lugar: New York; Año: 2011; p. 1 - 59

The world constraint of fossil fuels reserves with the resulting price increase (oil crisis) and the ever rising environmental pollution with severe consequences on the ecosystem (climatic change) have impelled strongly during last decades the development of renewable energy sources (RESs). The need of having available sustainable energy systems for replacing gradually conventional ones demands the improvement of structures of energy supply to ensure, on one hand the appropriate supply and quality of the electric power and on the other one, the saving and the efficient use of the natural resources preserving the environment. One technological alternative to achieve these goals consists of using clean non-conventional technologies of generation that use RESs that do not cause environmental pollution, such as wind, solar, hydraulic, biomass, thermal, among others. Recently, thermal power generation based on solid-state devices such as thermoelectric generators (TEG, aka thermopiles) has emerged as a potential alternative for clean energy generation, due mainly to their distinctive advantages such as technology innovation with increasing efficiency of cells (development of new semiconductor materials), simplicity of allocation, high reliability, absence of fuel cost, low maintenance and lack of noise and wear due to the absence of moving parts. Furthermore, they characterize a clean, pollution-free and inexhaustible energy source when are solar-powered. In addition to these factors are the irruption in the open market of various independent TEG module manufacturers and the marked cost reduction as a result of an augment in the world production (economies of scale). This trend is expected to be increased in the near future because of the many benefits of using RES, including government policy stimulus in many countries.   TEGs allow generating DC electricity directly and with no moving parts from a temperature difference held across the junction of two dissimilar semiconductor materials. These devices have been applied worldwide for the generation of small constant loads in isolated regions in the oil industry for at least 40 yr. They share the major characteristics of photovoltaic (PV) solar systems, but reaching today the fourth part of a PV array cost with similar peak power. Consequently, TEGs are presently arising as a feasible option inside the portfolio of new sustainable energy sources and are becoming serious candidates for both, traditional stand-alone and new grid-connected generation applications, especially in hybrid applications using waste heat or solar energy/geothermal conversion.   This chapter will present a thorough review on recent advances in developing thermoelectric power, including both applications, electrification of isolated rural areas and operation as new distributed generation systems in modern electrical grids. To this aim, major operating characteristics of these devices will firstly be analyzed and a detailed modeling approach will be presented, including the TEG modules and the design of the power electronic devices for connecting to the load in accordance with the given application. Eventually, the analysis of the dynamic performance of these devices and the impact of theirs use for both applications will fully be evaluated through an experimental set-up and a computational implementation in the MATLAB/Simulink environment.