Feasibility study on improving the performance of the kitchen exhaust system by integrating a supercharging fan

Abstract

Connecting a supercharging fan (SF) in series with the range hood is a practice way to better discharge the harmful oil fumes in residential kitchens, but a poor match SF may fail to help exhaust and even cause additional noise issues. This study aims to clarify how the SF rotation speed affects the operation of the existing range hood and explore the possible noise advantages of the series exhaust system. The computational fluid dynamics method was used to simulate the aerodynamic performance and internal flow of different exhaust systems. Analysis revealed that the system's exhaust capability can only be improved when the SF rotates fast enough, generating sufficient pressure rise to overcome its own flow resistance. Performance leading over the entire flow range is achieved when the SF rotates at 2500 rpm, where the pressure rise in the actual working range is increased by nearly 40%. These performance enhancements buy a rotational speed reduction of almost 300 rpm for the hood fan when the system's pressure remains unchanged. The airflow in the range hood thus decelerated by 14.5–18.2%, and the undesired reverse flows were also inhibited. The results obtained by full-scale kitchen experiments show that the sound pressure level of the series system was 0–1 dB lower than that of the original range hood in the same flow rate, and this decrement is maximum to 2 dB by inducing sound-absorbing treatment on the SF. This study provides preliminary guidance for integrating an SF in a range hood exhaust system, offering a novel view of its benefits and challenges.