Abstract. An experimental study of using coconut fiber as stack with varying density in
thermo-acoustics refrigeration system has been done. Stack is a device which is described as
the “heart” in thermo-acoustics refrigeration system. The length of stack is a fix parameter in
this experiment. The performance of the coconut fiber was evaluated from the density of stack
(varied from 30%, 50% and 70%), position of stack (varied from 0 to 34 cm from the sound
generator), and frequency of sound generator (varied from 150 Hz, 200Hz, 250Hz and 300Hz).
The inside, outside, and environment temperatures were collected every second using Data
Acquisition (DAQ). The result showed that the increase of stack density will increase the
performance of thermo-acoustics refrigeration system. The higher density produced
temperature differences in cold side and hot side of 5.4o
C. In addition, the position of stack and
frequency of sound generator have an important role in the performance of thermo-acoustics
refrigeration system for all variations of the density