A thermoacoustic refrigerator having a relatively small size which utilizes one or more piezoelectric drivers to generate high frequency sound within a resonator at a frequency of between about 4000 Hz and ultrasonic frequencies. The interaction of the high frequency sound with one or more stacks create a temperature gradient across the stack which is conducted through a pair of heat exchangers located on opposite sides of each stack. The stack is comprised of an open-celled material that allows axial, radial, and azimuthal resonance modes of the resonator within the stack resulting in enhanced cooling power of the thermoacoustic refrigerator.