Experimental study of the stack geometric parameters effect on the resonance frequency of a standing wave thermoacoustic refrigerator

Thermoacoustic refrigeration is an emerging technology that makes use of acoustic power to pump heat. The resonance frequency is important for the performance of thermoacoustic refrigerators, as it affects the temperature difference across the stack. This paper aims to optimize the performance of thermoacoustic refrigerators by experimentally investigating the effect of the stack geometric parameters (i.e. stack position, stack length, and the stack size) on the resonance frequency of a standing wave loudspeaker driven thermoacoustic refrigerator. Celcor Ceramic stacks of normalized positions of 0.764, 1.05, 1.43, and 1.72, normalized lengths of 0.076, 0.114, 0.153, and 0.191, and two porosities of 0.8 and 0.85 are used. The clarification of the relationship between the stack geometric parameters and the resonance frequency of the thermoacoustic refrigerator is presented. Moreover, the coefficient of performance of the thermoacoustic refrigerator is observed to increase at the resonance frequency of each stack configuration.