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Operating cooling devices on electricity generated by their own heat.

Publicado por FAMASE el 31/05/2013 (ENG)




Thermoelectric generators are devices which consume no electricity because they obtain the energy they need to function from the very heat they create. These generators convert heat directly into electrical energy using a phenomenon called the 'Seebeck effect' in which a temperature difference between two dissimilar electrical conductors or semiconductors produces a voltage difference between them.



When heat is applied to one of the two conductors or semiconductors, heated electrons flow toward the cooler one. If the pair is connected through an electrical circuit, a direct current (DC) flows through that circuit.



Thermoelectric generation is widely used in military and aerospace applications; the Mars rover Curiosity is a prime example of this. These applications are typically used for mid to high temperature environments (from 250ºC to 1200ºC).



To optimise thermoelectric applications for civilian purposes, the technology needs to be adapted to lower temperatures, which is the objective of the EU-funded GETER (Thermoelectric generation with residual heat energy) project at the Public University of Navarre, Spain.



Researchers at the university have produced a prototype of a self-cooling thermoelectric device that achieves 'free' cooling of over 30ºC. The objective is to develop this prototype into a system to run the converters and transformers used in renewable energy power stations, for example, wind, solar photovoltaic, solar thermoelectric and hydraulic energy.



"When these devices are in operation they generate heat and need to be cooled," explains David Astrain-Ulibarrena, head researcher on the project. "In many cases, heat exchangers with fans are used which need to be powered externally and thus consume a certain amount of electrical power.



"What we do is take advantage of the heat flow emitted by the power converters and transformers to produce the electrical power needed to make the fans work," he adds. "That way we achieve the cooling of the device and control its temperature, but without any energy cost."



This self-cooling thermoelectric application is just one of the lines of activity of the project partners, whose overall aim is to develop thermoelectric generators that allow low levels of heat energy to be converted into electrical energy; in other words, residual heat flows involving temperatures of less than 250ºC.



"The best future perspectives regarding thermoelectric generation have to do with making use of free heat sources, like residual heat flows," says Prof Astrain. "In Spain, 40 per cent of primary energy is wasted in the form of residual heat. This heat source is difficult to make use of with the conventional systems for producing electrical power, like steam and gas turbines."



Within the framework of this project, the research team has developed and experimentally validated a computational model showing that it can obtain up to 1 kW of electrical power for every cubic metre of an industrial flue pipe.



For more information, please visit:



http://www.unavarra.es



Category: Projects



Data Source Provider: Basque Research



Subject Index: Energy Saving; Other Energy Topics; Renewable Sources of Energy



RCN: 35651



Published in UE CORDIS



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