Theoretical evaluation of stack-based thermoacoustic refrigerators

Standing wave thermoacoustic refrigerator uses stack, is the heart of the thermoacoustic cooling system. The porous stack in the resonator tube develops temperature difference across the stack for heat pumping upon loudspeaker sound interaction of oscillating gas. In this paper, the optimization of stack-heat exchangers system and resonator is discussed using linear thermoacoustic theory for better COP and cooling power of refrigerator. The loudspeaker is assumed to provide the required acoustic power with the back volume gas spring system. Helium and air are chosen because of their better thermophysical properties and cost, compared to other competent gases. The 200 mm diameter stack is optimized for the temperature difference of 28 K. The theoretical results of the optimized refrigerator models are compared with the DeltaEC simulation results for deriving conclusions. DeltaEC predicts the cooling power and COP of 349 W at 0.998 for helium, and 139 W at 1.133 for air, respectively.