Performance of a 3D-printed stack in a standing wave thermoacoustic refrigerator

Successful standing wave thermoacoustic refrigerators reported to date still have issues with the stack, the primary medium of the system. Being the core of the whole system, performance of the stack directly influences the refrigerator performance. Besides the lack of a comprehensive theory on thermoacoustic cooling in establishing a good temperature difference across the stack that is very much desired, stack fabrication is still an issue. Currently, stack fabrication involved ready-made celcor ceramic material cut to specification or hand-made spiral/parallel plate stack from Mylar, the most commonly used stack material. The former comes in fixed off-the-shelf cells per square inch while the latter is susceptible to error and inconsistencies depending on the fabricator. This paper presents performance results from a standing wave thermoacoustic stack fabricated using a 3D printer, not reported to date. The stack design parameters selected has been optimized with Multi-objective Genetic Algorithm (MOGA) to determine the optimum design parameters; stack length, center position and plate spacing. The results show that the 3D-printed stack has potential towards improvement of the temperature performance of the thermoacoustic refrigeration system although a more refined fabrication technology is still in need. 3D-printing of the stack minimizes the error, eliminates inconsistencies, and reduces the time for the production of the final product. Consistency in optimized stack production is crucial towards realizing high performance systems. (C) 2017 The Authors. Published by Elsevier Ltd.