The benefit of kitchen exhaust fan uses after cooking - A CFD assessment

Abstract

Cooking is one of the most common activities in our daily life. Studies have shown that cooking may generate substances with hazardous particles or gases, which influence indoor air quality and cause a detriment to health. Although using a kitchen hood or an exhaust fan is an efficient way to remove harmful substances, entirely removing the hazard is still challenging. Our study aims to explore if leaving the fans on is an efficient way to remove the particles in kitchens by 3D Computational Fluid Dynamics (CFD) simulations. If so, how long should we leave the fans on? The 3D geometry of the CFD model of a kitchen was built using a real kitchen with windows as a reference to represent Taiwan’s typical kitchen style in real life. The simulation results were also compared and calibrated from experimental results. The validations agreed with the experimental results after adjusting the boundary conditions. Moreover, we used the validated model to conduct transient simulations for the four cases, including the case leaving the exhaust fan on and the case turning off the fan immediately. Results showed that leaving the hood on could remove more pollutants, but it still takes a while. Opening the window could speed up the removal of pollutants even without wind. Findings from this study could provide important implications for the benefit of kitchen exhaust fans and what to do when cooking is finished to protect residents from exposure to cooking emissions.