The effect of the strength of asymmetric heat load on indoor air quality with diffuse ceiling ventilation

Indoor air quality has a significant effect on performance of building occupants. In this paper, indoor air quality was studied when the heat load was located asymmetrically with diffuse ceiling ventilation. The test chamber was furnished like an office room with two laptops and two monitors, a heated manikin and a heated dummy. The highest heat load was 53 W/m² and reduced to 27 W/m² in three cases. The outdoor air was supplied through diffuse ceiling. The air flow rate used was 4.8 l/s∙ m², 3.9 l/s∙m² and 2.0 l/s∙ m² in the cases of 53 W/ m², 41 W/ m² and 27 W/ m². In term of the air change efficiency, the value of efficiency varied between 50% and 54.7%. Those values of air change efficiency are slightly better than the standard mixing ventilation. The observations indicate that the highest value of the mean age of air (67.7 minutes) is for 27 W/ m² and the lowest value of the mean age of air (21.6 minutes) is for 53 W/ m². The convection flows has a significant influence on air distribution. However, air change efficiency was above 50% in every measured location and the performance of the diffused ceiling ventilation is like fully mixed ventilation.