Recently, thermoacoustic refrigerators is considered as a new refrigeration technology because it has a lot of potential merit in the viewpoints of non-CFC medium, no moving parts, no noise/vibration, and achieving very low temperature. In this study, the physical characteristics of the resonator in thermoacoustic refrigerators has been studied and the design parameters are investigated. Temperature distribution on the stack was numerically estimated using the equation of energy flow rates through a cross section and the equation of energy balance in the stack. Based on the basic theory, a thermoacoustic refrigerator incorporating a Helmholtz resonator was built and its characteristics were investigated experimentally. The result showed that the designed resonator had poor performance due to the acoustic energy loss and inappropriate positioning of the stack. A theoretical parametric study was performed to find the optimal geometric conditions of the resonator. The resonator was re-designed based on the results of the parametric study for minimizing the energy loss. The obtained maximum temperature difference between hot and cold ends of the stack was 22.7℃ and the obtained minimum temperature at cold end was 4.3℃ for the newly built thermoacoustic refrigerator.
