Extremum seeking control of tunable thermoacoustic cooler

The performance of a prototype standing wave thermoacoustic cooler is optimized using an extremum seeking control algorithm. A tunable Helmholtz resonator was developed for a thermoacoustic cooler to change the boundary condition of the standing wave tube. The volume of the resonator is adjusted by changing the location of a piston on a ball-screw assembly driven by a DC motor. Multi-parameter extremum seeking control (ESC) was applied to optimize the cooling power via tuning of both the boundary condition (piston location) and the driving frequency. Experiments were conducted under both fixed and varying operating conditions. The experimental results demonstrated the effectiveness of ESC.