CALIFORCE3

The project aims to convert waste heat into electrical energy in an industrial process. For thermal pow-er less than 100 kW, thermodynamic cycles using turbomachines are not suitable due to low volumetric flow rates. An alternative solution consists in using volumetric expansion machines that are well suited for low power applications. A membrane expansion machine is considered here, which is perfectly sealed and requires no lubrication in contact with the working fluid. The proposed approach is to design an integrated system consisting of an reciprocating expansion machine and a linear alternator associ-ated with controlled power electronics to optimize the overall electromechanical conversion efficiency. The system will also be integrated into two low-power thermal energy conversion cycles, a thermochemical cycles and a Joule/Ericsson cycle. The identified challenges in the project are: • Thermodynamics: optimization of valve control to optimize the thermodynamic cycle. • Mechanical/Materials: design of electro-controlled valves, a linear alternator, and membranes supporting different working fluids. • Control command and power electronics: development of a control strategy allowing stable operation regardless of pressure, temperature, and working fluid. • Instrumentation: High-frequency temperature measurements in an environment subject to high mechanical and chemical stresses (gas, pulsed air, vibrations).