The effect of vent inlet aspect ratio and its location on ventilation efficiency

Abstract

The total energy consumption of buildings in China has been increasing year by year, ventilation energy consumption accounts for more than 20% of the total building energy consumption. The optimisation of ventilation system design aiming at energy conservation is of great significance while keeping healthy indoor air quality. However, the current codes and standards are still lacking specification requirements for vents design, e.g. inlet size ratio or position, which can greatly impact on indoor airflow and ventilation efficiency. In this work, we investigated the aspect ratios of vent inlets and their locations on indoor air quality. Both experimental and numerical simulation methods were adopted. Ventilation efficiency is represented with the local average peak concentration 〈C ̅*〉A,max. Results showed that when vent inlet is in symmetric conditions (i.e. located in the middle of the sidewall) and the aspect ratio between the length and width of the vent inlet equals to 4, ventilation removal efficiency showed the best performance. These findings are of great importance to the engineering applicability and able to provide reference for future design standards.

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