Impact of anthropogenic heat from air-conditioning on air temperature of naturally ventilated apartments at high-density tropical cities

Abstract

Natural ventilation is an important resource to cool down indoor areas at sub/tropical areas. However, within the high density urban context, anthropogenic heat from mechanical cooling system could have significant impact on the thermal environment at naturally ventilated indoor areas. This study focuses on residential neighbourhood and aims to develop evidence-based strategies to improve residential building design to mitigate the negative impact of anthropogenic heat. A parametric study was conducted using validated Computational Fluid Dynamics (CFD) models to investigate the impact of various design parameters, e.g., building typology, floor elevation, apartment location, and heat emission source location on the indoor air temperature increment (ΔT). First, the parametric study indicates that ΔT is generally lower at high-rise residential buildings than slab residential buildings. Secondly, lower ΔT at slab buildings with courtyards does not means better indoor thermal comfort because lower ΔT is caused by poor natural ventilation. Thirdly, the apartments located at the windward side of courtyard could have much higher ΔT than the ones at leeward side. When organizing hybrid ventilation for the buildings with courtyards, the ventilation direction is important to prevent heat entering the indoor areas from courtyard. Fourthly, significant increment of ΔT with increasing floor elevation is observed at slab buildings. Last but not least, changing heat source locations from the windward to leeward side could not help to decrease ΔT, but putting the heat sources at the façade parallel to the incoming wind could be very helpful. The above research outputs enable architects and planners to assess the current heat risk and take the necessary actions.