Impact of building facade on cooling efficiency and related thermal comfort for west oriented offices in Dhaka city

Abstract

Due to rapid global warming and other adverse effects generated by human activities, energy efficiency has become a major concern while designing a building. By introducing sustainable features in a building, energy costs can be reduced to a reasonable amount. According to studies, a building’s energy use is hugely influenced by the climate, building function, building occupancy, building envelope, building shape and construction. Building façade being the external envelop of the structure, is constantly exposed to the outdoor environment. Therefore, it can be said that ensuring preferable thermal conditions, by appropriate facade treatment, is one of the significant aspects, that can have major contribution towards energy efficiency in commercial office spaces, specifically in warm-humid conditions. This study deals with commercial office buildings, and ensuring energy efficiency is critical in these types of buildings, due to the huge areas of glass applied to their façades. In a day-use commercial building, the cooling load can be minimized, by adopting appropriate façade design. Many studies also show the relationship of thermal comfort with energy efficiency, and how human intellectual performance and perception in general, will reach maximum potential, if human beings are in comfortable thermal conditions. For this study, Gulshan Avenue located in Dhaka, Bangladesh, was selected as the study area, as it has commercial buildings, facing maximum heat penetration through west facades, during working hours. The goal of the study was to determine whether a relationship between energy consumption and facade treatment. Among all energy needs of a building, this research focuses only on the consumption for cooling. A questionnaire survey was also carried out to investigate thermal preference of the occupants. For the investigation, computer simulations have been carried out extensively, in an existing case building and also in a typical model, generated from analysing case buildings. Energy simulation tools in architectural practice are used for conducting the simulations. The simulation results reveal that, façade treatment on the west side of commercial buildings have significant impact on energy consumption, and these attributes are indirectly related to occupants’ thermal comfort. In this way the ultimate goal of the research i.e. to understand which type of façade saves more energy, making the internal environment comfortable, has been reached.

Keywords: Energy Consumption, building Façade, thermal Comfort, west oriented offices, energy efficiency, tropical climate, glass façades