Energy saving potential of screen walls in high-rise residential buildings in hot and humid climates

Abstract

About 33% of the total energy produced, is consumed by the building sector. Especially, 75% of the energy gets utilized by the residential buildings within the building sector. The increased usage of air conditioning systems to cool the indoor environment in hot-humid climatic regions increases the energy requirements of residential buildings. To be specific, high-rise residential buildings are known to be highly energy intensive. It is possible to mitigate the heat transfer into the indoor environment in high-rise residential buildings by shading the opaque facades. Since mutual shading or shading by adjacent building may not be possible at all times for high-rise residential buildings, screen wall can be used to shade the buildings to reduce its energy requirements and provide thermal comfort for the occupants in the indoor environment. In this background, the aim of the current research work is to find out the embodied energy, involved in the implementation of screen wall, and its effectiveness in reducing the operational energy requirements for space cooling in high-rise residential buildings. The option of screen wall and its benefits over conventional building envelope are emphasized in this study through a simulation study. A bedroom in a high-rise residential building in Chennai was chosen for conducting the detailed analysis and the analysis was carried through simulation for one year. The research design includes the modelling of the selected residential building in IES-VE software and validating the results through field measurements. Energy saving analysis was conducted through simulation to determine the energy saved in space cooling by shading the opaque façades with screen wall. For one year, 7.88MWh energy reduction was attained from the installation of screen wall over opaque surfaces at the set indoor temperature i.e., 27°C for 8 hours during night time using air-conditioning. The embodied energy was calculated for the installation of metal sheet over opaque façade and for shading as screen wall and the outcomes were compared with the energy savings in space cooling with the application of screen wall. The payback period for the embodied energy of the screen wall installation was determined in terms of operational energy saved in space cooling through screen walls. The analysis revealed that the payback period is one year. Due to COVID-19 pandemic, people staying at indoors in residential buildings has increased up to 90% during day time, which in turn results in high energy demand. Screen wall acts as a skin for the buildings and shade entirely from the sun. It helps in reducing the energy usage for space cooling in residential buildings, which eventually reduces the carbon footprint.