Influence of the natural makeup air system on the kitchen environment in low-energy buildings in severely cold regions

Abstract

As an essential part of residential buildings, kitchens may exhibit the release of large amounts of pollutants during cooking. However, it is challenging to extract heat and pollutants from kitchens in low-energy buildings (LEB) due to their high airtightness and low air permeability. Therefore, the natural makeup air system in kitchens of low-energy buildings is critical for improving the range hood performance. In this study, an environmental laboratory was established in Harbin to quantitatively investigate the exhaust of pollutants and analyze the impact of the natural makeup air system on the indoor environment in severely cold regions. Multiple measuring points were arranged to indicate the pollutant concentration in the breathing area and the indoor air temperature. The experimental results showed that natural makeup air could help control the diffusion of waste heat and cooking pollutants. The average concentrations of the total volatile organic compounds (TVOCs) and fine particulate matter (PM2.5) in the breathing area decreased by 45.0 % and 34.7 %, respectively, compared with those without the natural makeup air system. The natural makeup air system with a higher exhaust rate of the range hood (700 m3/h) could effectively reduce the TVOC and PM2.5 concentrations by 26.2 % and 83 %, respectively, compared with the system with an exhaust rate of 400 m3/h. Moreover, the trapping efficiency of the system for pollutants and waste heat highly depended on the temperature of the natural makeup air. Cold natural makeup air in winter could lead to thermal discomfort and higher pollutant concentrations than those in summer.