Investigation of flow behavior in a refrigerator machine room using magnetic resonance velocimetry

Abstract

This study aims to improve the energy efficiency and reduce flow noise in a refrigerator machine room by investigating the flow behavior using magnetic resonance velocimetry (MRV). A 1/2 scale model of the machine room was fabricated using stereolithography 3D printing, and the 3-dimensional mean velocity and turbulent kinetic energy (TKE) field were measured. Results from the reference model showed highly non-uniform flow distribution and high TKE regions. An improved machine room geometry was proposed, which led to an increase in mean flowrate through the condenser by 17.3% and a reduction in high TKE regions by over 77%, potentially resulting in improved energy efficiency and reduced turbulence-induced noise. These findings demonstrate the effectiveness of MRV in analyzing the flow behavior of complex 3D geometry such as the refrigerator machine rooms. The proposed improvements, including repositioning of flow-blocking pillars, relocating refrigerant pipes, changing inlet configurations, and increasing the area of inlet and outlet grilles, were validated using MRV. The results also confirm the accuracy of the MRV measurements, which were validated using an electromagnetic flowmeter. These findings have implications for the practical application of cooling systems and highlight the potential of MRV for future research in analyzing fan noise and applying MRV to models with built-in fans.