Improving efficiency of thermoacoustic refrigerators by a secondary source

Paper i proceeding, 2010

Improving efficiency and/or power are of key interest for heating and cooling devices, in particular thermoacoustic devices. Usually, thermoacoustic devices have a primary source attached opposite to the hard end termination of the resonator. The primary aim of this paper has been to investigate the potential of improving thermoacoustic devices by adding a secondary source replacing the hard end of the resonator. Using the secondary source the boundary conditions can be tuned arbitrarily. One specific case using a secondary source was studied closer: adapting the virtual length of the resonator together with the driving frequency. This case was investigated using simulations and parameter studies. The simulations were carried out using the time-domain model presented in a previous paper by the authors. Improvement in both efficiency and power were achieved by tuning the virtual length together with driving frequency. Moreover, these parameters may be tuned in real-time in an active control system using a secondary source.