Physics and methods of FGTM design

Functionally graded thermoelectric material (FGTM) is considered as one of the promising ways to improve the efficiency of thermoelectric energy conversion. Physical peculiarities of FGTM that consist in the use of not only contact, but also bulk thermoelectric effects originating in the inhomogeneous materials are described. The methods for finding optimal inhomogeneity are analyzed. The advantages of optimal control method are demonstrated. Typical examples of using optimal control theory for FGTM design for multi-stage cooling modules, the modules in optimal inhomogeneous magnetic field, singleand multi-stage generator modules are given. Improved efficiency of thermoelectric energy conversion when using FGTM is evaluated.