Evaluation of thermoelectric generators

With increasing emphasis on protecting the environment, many electrical power sources of unconventional nature are being investigated. One such source, which is not a new technology, is thermoelectric generation. The basic principles of thermoelectricity have been known for a hundred years, however, after the introduction of semiconductors in the 1950's thermoelectric generation enjoyed renewed interest and significant advances were made in both generator design and material fabrication. Unfortunately the rate of progress has tapered off recently and the field has reached a plateau where additional gains are becoming painstaking and expensive. This thesis provides a survey of the history and state of the art of thermoelectric generation, describes a computer program for the optimization of a thermoelectric generator (TEG), and illustrates the feasibility of operating a TEG using only waste energy as the heat source (i.e., waste heat, aerodynamic heating, etc.).

Two cases were considered to evaluate the performance of the TEG. The first case evaluates using exhaust gas from an industrial boiler as the heat source for the TEG. The results show that using a TEG (with an efficiency of 9.46%) 131.9 kW of electric power at 115 volts may be generated simply by recovering a portion of the total energy available in the hot gases. The second case assumes TEG operation near the material limits and shows that for large temperature differences efficiencies as high as 13.5% are attainable.