CFD analysis of the optimal installation location of adsorption material in two ventilation conditions in residential buildings: natural convection and mechanical ventilation

Recently, many studies have focused on the adsorption of pollutants as a method for improving indoor air quality. In Korea, the Health-Friendly Housing Construction Standards specify requirements for the installation of pollutant-absorbing materials. It is recommended that at least 10% of the total area of the living room and bedroom walls be covered. However, current guidelines regarding the installation locations of the adsorption material are unclear.  
The purpose of this study is to analyse (using CFD simulation) the optimal installation location of adsorption material under two ventilation conditions: natural convection and mechanical ventilation in residential buildings. A dressing room and bedroom were set up as representative spaces for the two conditions. In each space, the adsorptive effect was quantitatively analyzed by comparing the case in which the adsorption material was not installed with the case where in which adsorption material was installed on either the wall or the ceiling. The pollutant to be absorbed was set to toluene according to the Korean standard, and the adsorptive effect was evaluated by the reduction of toluene concentration per installation area. Our results showed that the dressing room showed the best adsorptive effect when the adsorption material was installed on the ceiling, which reduced the breathing zone toluene concentration by about 47%. We surmise that adsorption increased due to the pollutant’s tendency to rise in response to the buoyancy caused by the heat load generated by the occupant. On the other hand, in the bedroom, the adsorptive effect was the best when the adsorption material was installed on the inlet side wall, which reduced the breathing zone toluene concentration by 21% and the room average toluene concentration by 25%. This result is likely due to the close proximity between the occupant and the adsorption material and the fast air velocity of the inlet side wall. Therefore, under both natural convection and mechanical ventilation conditions, it is most effective to install the adsorption material where airflow is formed and air circulation is good.