Ravindran, S. K. T.; Huesgen, T.; Kroener, M.; Woias, P. (Laboratory for Design of Microsystems, Department of Microsystems Engineering - IMTEK, University of Freiburg, Georges-Köhler-Allee 102, 79110 Freiburg, Germany)
Huesgen, T. (ABB Schweiz AG, Baden-Dättwil, Switzerland)
Energy harvesting is projected to play a big role in creating energy autonomous sensors and sensor networks. Thermoelectric modules are currently employed to generate electrical power from a locally available spatial thermal gradient. Micro heat engines form an alternate class of mechanisms to transform spatial thermal gradients into electrical power. They are essentially miniaturized versions of macroscopic heat engines. Unlike thermoelectric devices, micro heat engines require the integration of an electrical power generator to produce electric power. Conventionally this is accomplished with an electromagnetic generator (EMG) which converts the mechanical energy generated by the heat engine into electrical energy. Owing to the scalability challenges associated with the EMG the power output measured for our device is only 392 pW. Hence, a non conventional method of electrical power generation by integrating a pyroelectric generator into a micro heat engine is investigated. The power generated is increased by four orders of magnitude, i.e. 3.02 muW, from the same spatial thermal gradient of 80 K.