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Energy conversion
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The development of new technologies for energy implies mastering the process of conversion between the different forms (solar, thermal, chemical, electrical, mechanical, etc.), as well as storage processes:

Solar energy can be directly transformed into electrical energy via the photovoltaic process and stored in accumulators. It can also be transformed directly into chemical energy (hydrogen) by photocatalysis. Electrical energy of every origin, can also be stored in the form of hydrogen, which can be used in fuel cells. The conversion efficiency is directly related to that of the associated electrochemical process (during electrolysis or use in a cell).

The thermoelectric effects Seebeck and Peltier allow the conversion of thermal energy into electrical energy and vice versa. Using the Seebeck effect allows recovering waste heat to produce electricity. Conversely, it is possible the Peltier effect allows locally cooling a device by application of a gradient of electrical potential. For a long time, these thermoelectric effects have very low yields and thus have found only marginal applications. The discovery of new promising materials, advances in nanofabrication and the growing desire to respond to energy saving requirements have revived research in this area.

Physicians and chemists of IRAMIS work to develop and optimize these different methods :

 

Several orientations are followed by the SPHYNX and GMT teams within SPEC:

  • Study of the thermoelectric conversion of various ionic solutions (SPEC/SPHYNX). The high values of the Seebeck coefficient, somewhat attainable a few mV / K, were measured in some well-chosen solutions containing macro-ions. These strong values reflect the strong entropy carried by these macro-ions, whose Seebeck coefficient is a direct measure.
  • Study the thermoelectric conversion in nanostructures (SPEC/GMT). The typical values of the thermoelectric coefficients as well as their mesoscopic fluctuations are studied in a quantum regime where the coherence of the electron plays a role. The case of doped nanowire arrays is particularly studied.
  • The ab initio description of thermoelectricity in nanostructures (SPEC/GMT).

 

 
#2686 - Last update : 01/08 2017

 

 

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