Thermoelectric Generators

Date: 2015-10-07; view: 610.

Almost 150 years ago the German physicist Thomas Seebeck dis­covered that the flow of heat through a metal segment could produce a voltage difference between its hot and cold ends. Although this Seebeck effect has since become familiar through its uses in instru­mentation, the field of application has been severely limited because of its low voltage and power output.

The recent development of new thermoelectric materials has now changed this condition, with the result that both the power output and the efficiency of thermoelectric devices have been raised to levels suit­able for the practical generation of power. A year ago, for example, Westinghouse was working with devices whose output was slightly over 1 watt; today a generator rated at 5,000 watts has been completed.

The qualities of thermoelectric devices that have impelled these devel­opments, particularly for military applications, include raggedness and compactness and, of course, the static nature of the devices. Heat is converted into electricity without moving parts. This freedom from mov­ing parts has several significant implications for defense; for example, in military power plants heat could be converted to electricity without noise. In space vehicles and missiles, this characteristic would permit the elimi­nation of gyroscopic forces that occur in rotating machines and so sim­plify guidance and stability in orbit. An even more basic advantage is that thermoelectric generators are inherently more reliable than rotating ma­chines and may eventually prove lower in first cost.