Flow rate and capture efficiency of domestic kitchen exhaust hoods for Chinese households

The building regulations of most countries require every kitchen to be provided with a window that opens into the external air. This alone is not an effective means for avoiding the contaminants generated during cooking from spreading into other parts of a residential flat. Many households equipped their kitchens with a range exhaust hood, with make up air drawn into the kitchen through an open window. Compared to other ventilation requirements in dwellings, the ventilation rate required for this purpose would be the highest, but would only need to be maintained for a relatively short time. The regulatory requirements pertaining to kitchen windows impose severe constraints on the layout design of buildings and increase the construction cost whilst the functions of the window can alternatively be fulfilled by the provision of artificial lighting and mechanical air supply and extraction systems. This paper reports the results of an experimental study on the capture efficiency of domestic kitchen exhaust hoods. The required parameters in a model for predicting the capture efficiency of such exhaust hoods were determined for application to typical Chinese cooking using a wok over a gas stove. The ventilation rate required for achieving satisfactory fume capture efficiency can then be determined, which is crucial to the design of the ventilation systems for the next generation of residential buildings with windowless kitchens.Department of Building Services Engineerin