Optimization of the thermal performance of building double-skin envelope

• Main Author: Chua, Wei Jin
• Other Authors: Li Hua
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/60286
• Institution: Nanyang Technological University

Singapore is geographically situated close to the earth's equator. Thus, Singapore does not experience any seasonal change instead, Singapore experience a hot and humid climate throughout the year. Due to the hot and humid climate that Singapore experience throughout the year, residence of Singapore rely a lot on the use of the air-conditioner to achieve thermal comfort in their everyday life. But it was found that the excessive use of air-conditioner, not only in Singapore, has given rise in the mean global temperature or in other words, global warming. Therefore, to slow down the rise in the mean global temperature, a double-skin roof technology was used to reduce the heat produced by the sun from getting into the building. When less heat gets into the building, thermal comfort can be achieved much easily and also reducing the usage of air-conditioner. The objective of this study is to obtain the optimum parameter for the construction of a double-skin roof such that the double-skin roof performs at its highest efficiency in reducing the heat from entering the building. As such, the parametric study of the double-skin roof will be conducted via modern technology, which is the use of computational fluid dynamic (CFD) simulation. The use of CFD simulation greatly reduced the research time and also the research cost. However, the reliability of using CFD simulation in the parametric study will need to be validated first. The validation of the CFD model will give the confident of how well the results obtained through CFD simulation will work in a real life case. Parametric studies include the change in the roof inclination angle, the change in the gap height between the plates in the double-skin roof and lastly, the use of insulations and radiant barriers inside the double-skin roof. From the parametric studies, it was found out that the double-skin roof efficiency increases as the roof inclination angle increase and finding shows that the optimum inclination angle is 40 degrees. As for the air gap height, the optimum air gap height differs for every parameter change in the double-skin roof. A roof without radiant barriers or insulations was found to have an optimum air gap height of 8 cm. When radiant barriers are installed, the optimum air gap height changes to the range of 9.5 cm to 10 cm. No conclusion was made for the optimum height when insulations are installed, as the efficiency continues to rise even after reaching the maximum gap height of this study. Lastly, the use of radiant barriers and insulations works best when it is installed on both sides of the plate. In summary, findings show that the efficiency of using radiant barriers and insulations in the double-skin roof is very much more efficient than changing the inclination angle and the air gap height. But to achieve the highest efficiency of the double-skin roof, the inclination angle and air gap height will still need to be considered. Furthermore, possible future works in the study of the optimization of the double-skin roof have been proposed.