Numerical Modeling and Performance Evaluation of Standing Wave Thermoacoustic Refrigerators with a Multi-Layered Stack

Abstract

Thermoacoustic refrigerators have huge potential to replace conventional refrigeration systems as an alternative clean refrigeration technology. These devices utilize conversion of acoustic power and heat energy to generate the desired cooling. The stack plays a pivotal role in the performance of Standing Wave Thermoacoustic Refrigerators (SWTARs), as the heat transfer takes place across it. Performance of stacks can be significantly improved by making an arrangement of different materials inside the stack, resulting in anisotropic thermal properties along the length. In the present numerical study, the effect of multi-layered stack on the refrigeration performance of a SWTAR has been evaluated in terms of temperature drop across the stack, acoustic power consumed and device Coefficient of Performance (COP). Two different aspects of multi-layered stack, namely, different material combinations and different lengths of stacked layers, have been investigated. The combinations of four stack materials and length ratios have been investigated. The numerical results showed that multi-layered stacks produce lower refrigeration temperatures, consume less energy and have higher COP value than their homogeneous counterparts. Among all the material combinations of multi-layered stack investigated, stacks composed of a material layer with low thermal conductivity at the ends, i.e., RVC, produced the best performance with an increase of 26.14% in temperature drop value, reduction in the acoustic power consumption by 4.55% and COP enhancement of 5.12%. The results also showed that, for a constant overall length, an increase in length of side stacked material layer results in an increase in values of both temperature drop and COP.

Impact of stack length on performance of standing wave thermoacoustic refrigerator

“…For the model, the study used a 2D axisymmetric model, conjugate heat transfer, laminar flow coupled by nonisothermal flow multiphysics. The type of fluid flow used was determined by calculating the Reynolds number (𝑅𝑅 𝑒𝑒 ), which referred to as the critical Reynolds number limited to 2300, (𝑅𝑅 𝑒𝑒𝑒𝑒𝑒𝑒 = 2𝑢𝑢 1 /√𝑉𝑉𝜔𝜔 ) [19]. A time-dependant solution option was utilised.…”

“…In a study by Bhatti et al (2020), they compared homogeneous stacks using Celcor and Kapton to multi-layered stacks combining Celcor and RVC, and Kapton with RVC. In the multi-layered stacks, they found a temperature increase of up to 26.14%, an 8.5% enhancement in COP (Coefficient of Performance), and a 4.55% reduction in energy consumption.…”

Study of the Relationships among the Reverse Torque, Vibration, and Input Parameters of Mud Pumps in Riserless Mud Recovery Drilling

“…Additionally, the ANSYS software has numerous applications in other fields. ANSYS software was used by Bhatti et al [32] to numerically model and evaluate the performance of a standing-wave thermoacoustic refrigerator with multiple stacks. The ANSYS Fluent software package was used by Hamdamov et al [33] to conduct mathematical modeling of vertical axis wind turbines.…”

Experimental Investigation on the Thermoacoustic Effect in Easily Accessible Porous Materials

“…A bulk porous media representing stack in a thermoacoustic systems, such as RVC foams, were analytically studied by Tasnim et al [29]. Bhatti et al [30], in turn, numerically investigated the multi-layered stacks, that are composed of different materials. Their results showed that multi-layered stacks consume less energy and provide higher COP than their homogeneous counterparts.…”