Combined experimental and numerical study on the performance of thermoacoustic refrigeration system

Thermoacoustic science focuses on the interaction between sound energy and heat energy and the thermoacoustic refrigeration system uses sound wave to attain a temperature gradient along a porous solid medium (stack). It is an emerging technology to replace conventional refrigeration system with the benefit of having no moving parts. In the present study, the effects of the material, length, and position of the stack inside the resonator tube on cooling effect across the stack are examined. Three different materials-nylon, ABS plastic and wood are used as stack material which yield a cooling effect in the range of 2-5°C across the resonator tube (length of 60 cm) depending upon the stack position at resonant frequency (145 Hz). Three samples of each stack (length of 3, 6, and 9 cm) are placed at a spacing of 10 cm inside the resonator tube. Operating frequency is constant at 145 Hz which is resonant frequency. Highest temperature difference is obtained for ABS plastic stack of 3 cm length at the closed end of the tube at resonant frequency. The maximum cooling load is observed at the closed end of resonator tube, but the coefficient of performance (COP) is found to be maximum at the open end (driver end) of the tube. The performance of the thermoacoustic system is numerically analyzed using DeltaEC software for the same set of operating conditions and is compared with the experimental findings.