Shape optimisation of residential mid-rise buildings for reduction of energy demand in temperate climate

B.C Dorresteijn (Delft University of Technology and ARUP)

Shape has long been an important parameter in improving the internal comfort of buildings and reducing energy demand.  Using a shape factor to reduce the building envelope and to minimise thermal loss is incorporated into the Dutch Building codes for a long time, aimed at a comfortable climate and low energy demand. Since living in spherical buildings like igloos, in the Netherlands has a large number of disadvantages, building shape is adapted to fit both demands for low energy use and high thermal comfort, but efficiently using space and allowing for daylight entrance. Since building design has shifted to becoming more digitised, advantages of increasing computational power can now be used to improve building shape in new ways. Parametric design is a way to generate a large number of  building designs in a short amount of time. Optimisation software can assist to analyse and optimise the design.

By making use of Grasshopper a parametric design model is created. Using this model a large variety of building designs was generated which are analysed on their daylight entrance and energy demand using Honeybee and Ladybug. By analysing the outcomes of these performance analyses, the window-to-wall-ratio and shape, quantified by shape factor Lc, of these designs were optimised using the autonomous optimisation algorithm pilOPT in modeFRONTIER. The optimisation objective is to minimise the total energy demand for heating and cooling. This is assessed by calculating the normalised energy demand for heating and cooling for both a summer and winter period. To execute the optimisation, the Erasmus Campus Student Housing project by Mecanoo in Rotterdam was used as a reference project.