IMPACT OF FACADE FEATURES ON INDOOR THERMAL COMFORT IN RESIDENTIAL BUILDINGS

Abstract

With the rising energy costs, and the potential sickness related to the prolonged stay in air-conditioned space, natural ventilation needs to be considered in the residential buildings in Singapore. There are two components to be considered for natural ventilation, one is the climatic conditions, and the other is building façade. In Singapore, it is hard to alter the tropical climate, therefore, in looking at natural ventilation, the building façade features will be examined. In this paper, the impact of façade features will be discussed. Field measurements of 7 units are conducted to examine the impact of building orientation on the indoor air temperature near windows, walls and façade surfaces. It is found that in July, the north-facing façade is experiencing the highest recorded temperature, due to the orientation of the Sun. Contrary to popular belief, the comparison of units with various WWR showed that the larger WWR would not result in better thermal comfort levels for the occupants as shown from the PMV graph drawn. A six-day data is taken to analyse and evaluate the indoor thermal comfort levels by plotting a PMV graph. It is found that about 70% to 80% of the time, the predicted thermal comfort level is within the PMV range between -1 to 1. The north-facing façade recorded a 15% more time being thermally uncomfortable than a east-facing façade. Moreover, by reducing the WWR from 1 to 0.5, there is an improvement of 13% of the time being more thermally comfortable. Therefore, it is recommended that the north-facing façade to install shading devices as well to prevent direct solar radiation and reduce the size of windows.