Thermoacoustic refrigeration is an emerging green, novel and promising alternate technology compared to vapor compression refrigerator systems for domestic cooling. It uses environmentally benign gases like air or helium or the mixture of inert gases as working substances and has no moving parts, no lubrication and no vibration. The cooler is designed and optimized with helium and air as refrigerants operating at 10 bar with 3% drive ratio for the temperature difference of 28 K and stack diameter of 200 mm using linear thermoacoustic theory. In this paper, the effect of gas blockage (porosity) of the spiral-stack heat exchanger system ranging from 45% to 85% on the theoretical performance of the cooler is discussed. The one-third and one-fourth wavelength convergent–divergent resonator designs are optimized with air and helium as working substances, respectively, to improve performance and power density. The optimized coolers show best performance with 85% porosity. The theoretical results are validated with DeltaEC software simulation results. The simulation results show the coeffcient of performance and cooling capacity of 0.93 and 219 W for helium and of 0.50 and 139W for air, respectively, at the cold heat exchanger temperature of 0ºC.