Numerical investigation on the influence of natural make-up air in Chinese-style residential kitchen on indoor environment in a partitioned household

Abstract

In domestic kitchen, cooking leads to heat generation and particle diffusion. Due to heterogeneous air mixing in partitioned spaces, difference of indoor environment between kitchen and adjacent room exits. However, study on indoor environment in adjacent room caused by cooking is not enough. Natural make-up air from exterior window openings or cracks are still the current widely used in Chinese-style residential kitchens (CRK). This study aims to predict airflow and particle distribution in a partitioned indoor environment with a CRK. Natural make-up air from exterior kitchen window, including disorganized, air infiltration and organized airflow were defined. Computational fluid dynamics method was applied to investigate velocity, air temperature, particle concentration and airflow in adjacent room. Results show that overall indoor velocity magnitude under insufficient make-up air from exterior window was two times than that under enough make-up air. Velocity magnitude in vertical and horizontal direction was quite different, but there was little difference in different position in breathing zone. Temperature difference in adjacent room ranged from 0.5 to 2.2 °C. Up to 31.8 °C was observed in disorganized make-up air in summer condition, which could lead to thermal discomfort. PM2.5 mass concentration in adjacent room could be largely reduced by organized make-up air from kitchen window. Under air volume of 810 m3/h in the model, simulated PM2.5 mass concentration in indoor environment was the lowest. With appropriate organized make-up air volume, concentration could be largely reduced. But excessive make-up air could lead to more particle diffusion from kitchen to adjacent room. Furthermore, airflow from living room to kitchen indicated a possible transmission of contaminated pollutant from dry floor drain to the living environment.