Thermal Design, 2nd Edition

5Thermoelectric Design

5.1 INTRODUCTION

Thermoelectrics is literally associated with thermal and electrical phenomena. Thermoelectric processes can directly convert thermal energy into electrical energy or vice versa. A thermocouple uses the electrical potential (electromotive force) generated between two dissimilar wires to measure temperature. Basically, there are two devices: thermoelectric generators (TEGs) and thermoelectric coolers (TECs). These devices have no moving parts and require no maintenance. TEGs s have great potential for waste heat recovery from power plants and automotive vehicles. Such devices can also provide reliable power in remote areas such as in deep space and mountaintop telecommunication sites. TECs provide refrigeration and temperature control in electronic packages and medical instruments. Thermoelectrics have become increasingly important with numerous applications. Since thermoelectricity was discovered in the early nineteenth century, there has not been much improvement in efficiency or materials until the recent development of nanotechnology, which has led to a remarkable improvement in performance. It is thus very important to understand the fundamentals of thermoelectrics for development and thermal design. We start with a brief history of thermoelectricity.

In 1821, Thomas J. Seebeck discovered that an electromotive force or a potential difference could be produced by a circuit made from two dissimilar wires when one of the junctions was ...