Reduced model for the comprehension of the operation of a thermo-mechanical energy harvester

The bimetallic strip heat engines are thermal energy harvesters that have been designed to convert low-grade heat flux coming from local thermal gradients into mechanical energy by using the thermo-mechanical instability of bimetallic membranes. Great efforts must be done on the modeling of these heat engines in order to understand their way of working. This paper is a contribution to these efforts since it proposes approximate analytical expressions of the efficiencies of these heat engines and figures of merit to compare bimetallic beams.