Acknowledgements

Where, Rc�<sup>P</sup> y Rc�<sup>N</sup> values are defined by slope interception with y axes. Such values are shown as inset table of Figure 14. This result is the total parasitic resistance of thermoelectric module with nine pairs of asymmetrical legs that includes the wiring resistance of wire used

Figure 14. Electrical resistance in asymmetrical thermoelectric legs as the length is increased.

Module ZTc ZTp Symmetric 0.43 0.79 Asymmetric 0.73 1.02

Now, contact resistance Rc of the thermoelectric module with asymmetrical legs is calculated as:

RC ¼ Rp�asymmetric � RW

RC ¼ 191:97 mΩ � 18:38 mΩ

RC�asymmetric ¼ 174 mΩ

In this particular case, Rp has been obtained around 116 mΩ y 183 mΩ for the symmetrical and asymmetrical device, respectively. Using this information, ZTp can be calculated as it is shown in Table 2. However, by correcting such parasitic effects the estimated values on ZT<sup>p</sup> are 0.79 and 1.02 for the symmetrical and asymmetrical thermoelectric modules, respectively. Thus, it is

Table 2. Effect of contact and parasitic resistances on ZT of thermoelectric modules with symmetrical and asymmetrical

during measurements as well as contact resistance.

118 Bringing Thermoelectricity into Reality

legs, respectively.

This work was supported by the National Council for Science and Technology-Conacyt Mexico, through the Grant for fundamental research No. 241597 and national issues No.1358. A.F. M. thanks to Conacyt Mexico for fellowship, as well as the thermoelectric laboratory at the Cardiff University for facilities.
