A model for calculating single-sided natural ventilation rate in an urban residential apartment

Abstract

Natural ventilation is an energy-efficient ventilation method for residential buildings, but it is not easy to determine the natural ventilation rate. This investigation developed a simple model for calculating the ventilation rate for an apartment with single-sided natural ventilation with buoyancy and wind pressure effects, based on a wind-driven model. To validate the model, field measurements were conducted in an apartment in an urban residential building in Tianjin, China. The experiment measured indoor and outdoor air temperature, wind speed and direction, wind pressure coefficient at an opening of the apartment, and ventilation rate through the single opening. The results indicated that the wind pressure coefficients calculated by Eq.12 did not agree well with the measured data. However, most of the measurements show a stronger buoyancy effect than wind pressure effect. Our new model was able to predict the ventilation rate with an average error of 13.1%. When we used six other models found in the literature to predict the ventilation rate, the errors ranged from 12.9% to 46.1%. Thus, not only does our model perform very well in predicting the ventilation rate, but it also shown the interaction between buoyancy and wind pressure.