Thermoelectric effects , discovered in the mid-upper term of the 19th century ,had been less applied in practical projects during more than 100 years after its discovery because of its inefficiency , but the discovery of materials with high thermoelectric properties made thermoelectric effects be applied in practical projects in 1950's , which involved many fields , such as national defense , industry agriculture , medicine , commerce , daily lives and so on .
On the analysis of fundamental princi...