Facades as a new sustainable approach towards the mitigation of UHI in the tropical climate of Malaysia

Abstract

Major cities and urban areas in Asia are undergoing significant urban changes, and Kuala Lumpur is no exception. The city has grown to have the highest level of urbanization in Southeast Asia. Urbanization has been identified as a cause to the current climate change effecting average global temperature to rise. This phenomenon has a significant impact on the environment, especially in densely built cities and urbanized areas, causing the urban heat island (UHI) effect. UHI effect and indicator is the increase in air temperature in urbanized areas as compared to the more rural areas. Numerous studies had suggested that the cause of the UHI effect is anthropogenic with the building sector taking the fullest blames. Studies indicate that mitigation measures are needed to reduce the UHI. Buildings and buildings facades have significant influence on not only the indoor space of a building but to the outdoor space as well. Not many studies have been done to uncover the correlation of building facades with the increment of heat in the surrounding areas. Utilizing data monitoring from field survey and validating with computer simulation this study investigated the correlation. Findings from data monitoring of seven tall buildings with different façade designs revealed that fully glazed facades (FGF) potentially raised the surrounding ground surface temperature by as high as 9 °C during the day and cooled down only slightly at night as compared to the outdoor meteorological temperatures. In comparison, buildings using the Double Skin Façade (DSF) system (non-glazing) and Green Skin Facade (GSF) system, showed lower recorded temperatures. Notably, the night-time results indicated potential mitigation measures to the UHI effects. In validation to the field survey, the ENVI-met Environmental Simulation software was utilized for the correlation of the recorded temperatures with the different facades. Higher outdoor temperatures than the maximum comfort level was found for the building facades using FGF. This is regardless of the façade systems whether they are utilizing DSF and GSF. The results also show that materials other than full glazing were able to mitigate the solar reflectance effects better at the urban street level by maintaining the lower temperature than the reference temperature. Thus, climatically suitable façade systems such as the DSF and GSF had higher competence towards mitigating the UHI. The contribution of this study to the body of knowledge of UHI mitigation measures regarding building facades is pertinent to the urban heat canyons of Kuala Lumpur. Therefore, future studies are recommended to put forward new solutions for the building envelope systems and materials that are mindful of the local climate and diverse urban contexts while being economically justifiable. Moreover, further understanding on the UHI intensity are also required towards mitigating the UHI effects in various urban settings of the city.