Design and Analysis of a Thermoacoustic Cooling System with Two-Stack Arrangement for Different Types of Stacks

Thermoacoustic cooling is a method that converts acoustic power to temperature differential, which is then utilized to reduce the temperature of a hot body via heat exchangers. A typical thermoacoustic cooling system consists of a resonator, stack, driver and heat exchangers. Any thermoacoustic cooling system is categorized based on the frequency at which it operates which again controls the geometry of the resonator. A half-wavelength resonator will have two pressure antinodes, where stacks can be placed to obtain the temperature difference. The main objective of the present work is to design a half-wavelength resonator with two-stack arrangement and to analyse and compare the refrigerator’s performance for various types of stacks. The resonator’s length for the cooling system is chosen as 1 m, and it operates at a frequency of 500 Hz with helium as a working fluid at a temperature and pressure of 288.05 K and 10 bar, respectively. The drive ratio of the refrigerator is 0.03. The stacks are 4.295 cm in length with a thickness of 0.5 and 1 mm spacing between the adjacent stack plates. The placement of stack 1 is 35 mm from the driver end and of stack 2 is 35 mm from the closed end of the resonator. DeltaEC is an open-source tool used by many researchers for thermoacoustic problems. DeltaEC simulations for parallel, rectangular and circular type stacks show a temperature difference of 37.27 °C, 40.05 °C and 53.05 °C at stack 1, whereas a temperature difference of 8.07 °C, 12 °C and 20 °C at stack 2, respectively. Introducing ambient and cold heat exchangers adjacent to each of the stacks makes it possible for the refrigerator to take two heat loads at the same time. This increases the net cooling capacity of the refrigerator.