Characterization of the Thermodynamic Working Cycle in a MEMS-Based Micro Heat Engine

This work examines the conversion of thermal to mechanical energy in a micro heat engine by characterizing the heat engine’s working cycle. Results are given for dynamic measurements of pressure, volume, and temperature throughout the working cycle of the engine. Engine pressure is determined from the deformation of the two membranes in contact with the working fluid. A Michelson interferometer is used to measure the center deflection and displacement profile of both of these membranes. Pressure is determined from the membrane deflection using experimental static pressure-deflection curves. Engine temperature is measured using electrical resistance thermometry, via a micro resistance thermometer fabricated on the surface of a silicon membrane exposed to the working fluid in the engine cavity.