Effect of the blockage ratios of circular stack on the performance of the air-based standing wave thermoacoustic refrigerator using heat pipe

In this study, the coefficient of performance (COP) and relative coefficient of performance (COPR) of an air-based standing wave thermoacoustic refrigerator (ASWTAR) was investigated. All relevant components of the thermoacoustic refrigerator were fully available in the system. Heat pipes with a total heating power of 30W were installed into the cold-side and hot-side heat exchangers. The circular stacks with plugging ratios of 0.67, 0.71 and 0.74 and the spiral stacks with plugging ratio of 0.74 were tested and compared. The results show that the circular stack is the optimum stack geometry for ASWTAR. Similarly, a circular stack with a blockage ratio of 0.71 has the best performance, producing the lowest cold side temperature (T-c) and the highest temperature difference (Delta T-m). Under no cooling load and 2W cooling load, T-c, Delta T-m, COP and COPR were 22.4 degrees C, 30.5 degrees C, 0.93 and 9.57%, respectively. Finally, it is clear that due to the use of more suitable materials, the COP and COPR of a circular stack are greater than those of a spiral stack.