Shape optimisation of a second skin

What can be achieved - in terms of structural and building physics performance - when an existing skin of a building is removed and replaced by a new facade

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Abstract

To reach the European Union climate targets of 2020 the rate of refurbishment must increase. The problem is that there are many barriers to refurbishment, which causes a low rate and low quality. The objective is to overcome these barriers and stimulate facade refurbishment. This thesis looks at the improvement, that can be made when replacing an existing skin by a new facade focusing on improving the structural efficiency and touch upon building physics.
The main driving forces of this thesis are parametric design and optimisation. A parametric design is crucial for this thesis to perform a variation study. Different shapes of the facade are simulated with a custom made genetic algorithm to optimise the shape of the facade. First of all, the cost can be influenced by minimising the amount of material by altering: cross-sections, beam distances, etc. Secondly, by changing the shape of the facade a more aerodynamic building can be created. When the curvature increases, the wind load can be reduced which can make the structure more efficient. The wind load on the facade is determined with the computational fluid dynamics (CFD). The part about building physics focusses on ventilation. A ventilation system is designed which emphasises the importance of integrating the ventilation system with the second skin. The design builds upon the results of the CFD simulation and the structural model. The performance of the system is quantified by determining the usage of natural resources.