| dc.description.abstract | Current global challenges as climate change, population increase and urbanization creates the need for sustainable cities with high population density, and thus taller buildings. Building tall typically requires additional material quantities, resulting in higher embodied greenhouse gas emissions. Cities' total energy consumption and emission is better understood, if a possible "premium" of building tall is found, with respect to embodied energy and emission of construction materials in tall buildings. Therefore, as a step towards this understanding, this study contributes to the topic by examining the tall building facade system and it s environmental impact in terms of material GHG emission and lifespan.
For this purpose the following research question is investigated: Will increased building height affect the facade system in form of additional materials, leading to increased embodied carbon, resulting in a CO2-premium? In this context a CO2-premium means: increased GHG emissions per square meter ground floor area (GFA) area with increasing building height.
This study has investigated the climate change (CC) impact in GHG emissions caused by materials in the facade system for increased building height.
LCA is used to calculate the material GHG emissions per gross floor area in the production stage in a case study of a 17 floors high office building. The CC impact per GFA is calculated for a Curtain wall element facade in a building of 3, 7, 12 and 17 floors. The elements in the facade-wall (modules) and the fixings of the facade is included in the scope. The scope of the study is limited to cradle-to gate, and the study only addresses one type of facade systems. There is a necessity to do case studies of more facade system to draw a more reliable conclusion.
The results reviled that for all floors from 1 to 17, there exist a CO2-premium for the curtain wall element facade. The premium is highest at the lower floors, from floor 3 to 7 the CO2-premium increases by 19 %. For the middle floors, floor 7 to 12, the increase is only 4 % relative to floor 7. While the last floors, from 12 to 17 the CO2-premium has a 7 % increase. The modules, consisting of mainly float glass and aluminum, where the main contributors to the CC impact of the facade. The fixings were negligible for the CO2-premium, due to their small material quantity compared to the modules.
However, after more thorough investigation of the reason for the premium - thus, investigating the cause of the material quantity increases in the facade system - the results reviled that the CO2-premium of this facade is caused by design and structural changes related to design of the facade. Consequently, regardless the clear result implying a CO2-premium of the facade, related to the aim of this study, this premium is not caused by an increase in building height of the facade. The CO2-premium exist because of changes in design of the facade system. From these results this study cannot conclude that there is a CO2-premium for curtain wall systems when building height increases. Further investigation is needed. | en |
