Improving indoor air quality and thermal comfort in residential kitchens with a new ventilation system

Chinese kitchen environment is usually hot and humid in summer and cold in winter, while people spends considerable time there. This investigation firstly assessed the indoor air quality and thermal environment in a kitchen in summer in Changsha, China. Sixteen cooks were asked to prepare the same dishes in the kitchen. The study measured skin temperatures of the cooks and environmental parameters (air temperature, CO, CO2, TVOCs, and PM2.5) and recorded their thermal sensation votes using questionnaires at the same time. The results show that the thermal environment in the kitchen was highly non-uniform and too hot in summer. The air temperature in the kitchen could increase 5.3 degrees C during cooking. TVOCs and PM2.5 concentrations exceeded the limits by Chinese standards in the kitchen. Thus, this investigation proposed a new ventilation system to improve the indoor environment in Chinese residential kitchens. The new ventilation system had upward air curtains around the gas stove and conditioned air from the cabinet under the stove. A systematic numerical study using the steady state RNG k-epsilon model was performed to optimize the integrated system design for both summer and winter conditions. Experimental measurements were conducted in a kitchen mockup to verify the performance of the new system. The measured capture efficiency of the new system was 96.2%-97.1%, the predicted dissatisfied percentage (PD) distribution around the cook smaller than 20%, and the vertical temperature difference between head and feet -0.9 degrees C.