Author(s)

NURUL ASYIKIN ABU BAKAR, CLAUDIA NICOLAI, NADA TAOUIL, DESMOND H. LIM, MOHAMMAD JADIDI, MAHDI AZARPEYVAND

Abstract

Natural ventilation can facilitate the outdoor generated pollution into indoor spaces. Therefore, understanding outdoor–indoor scalar transport in conjunction with the flow pattern is crucial to the evaluation of the ventilation performance. The present experimental investigation aims to clarify the behaviour of a pollutant transported in a classroom through different types of window configuration. To this purpose, a scaled classroom model with a windward window and an aligned leeward window, was placed at the centreline of the test section of the boundary layer wind tunnel facility at the University of Bristol. The pollutant concentration and velocity fields within the building were measured by combining hot-wire anemometry and fast flame ionisation detector for three window configurations, namely, fully open (referred to as base-open), top-hung and pivot-hung windows. The incoming flow was an atmospheric boundary layer generated with Counihan’s flow conditioning at a free stream velocity of 2 m/s. The scalar was released upstream of the model from a point source at 50 mm above the floor. The results demonstrate that the window configuration dictates the flow pattern which directly governs indoor pollutant distribution within the classroom. The base-open yields the highest ventilation rates while leading to the highest levels of pollutant transported indoor. In contrast, top-hung provides the most balanced performance maintaining high ventilation rate and reduced indoor concentration level. These findings can inform window selection strategies to achieve acceptable ventilation levels and air quality within educational premises in polluted areas.

Keywords

scalar transport, indoor pollution, wind tunnel experiment, natural ventilation, window design