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

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

Dorresteijn, Bo (TU Delft Civil Engineering and Geosciences)

Schipper, H.R. (mentor)
Pasterkamp, S. (graduation committee)
Turrin, M. (graduation committee)
Debets, N.A. (graduation committee)

Delft University of Technology

Civil Engineering | Building Engineering - Structural Design

2020-08-26

Shape has long been an important parameter in improving the internal comfort of buildings and reducing energy demand. This can be seen from historical vernacular architectural typologies, like igloos, which have minimal thermal loss surface to provide a comfortable internal climate.  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. This research is focussed on optimising building shape to reduce energy demand but combining this with demands for thermal comfort and daylight entrance.  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.  The optimisation results show more compact buildings, with low WWRs have lower energy demands. This can also be seen from the Pearson correlation between the Lc [m] and the normalised energy demand [kWh/m2]. Which is found to be -0.624 for the first optimisation and -0.632 for the second optimisation. This confirms current building practice in which the relative building envelope is tried is be reduced.  Low WWRs (< 0.2) can obtain a minimum daylight factor (DF50%) of 2.1%, which is lower than current practice. However, the minimum WWR is largely affected by the presence of neighbouring buildings. For facade orientations with adjacent buildings, minimum WWR is significantly higher (up to 0.8). Since buildings outside the own plot are not considered in the daylight calculation according NEN 2057 and the new NEN-EN 17037 situations may occur where buildings will obtain legal requirements but acquire poor daylight entrance. For future building shape optimisation studies, it is recommended to make use of visible part of the sky analysis (VSF) in the assessment of daylight criteria. Using VSF can save minutes of computation time per building analysis thereby speeding up the optimisation process. Recommendations for further research following this thesis are to: enlarge the number of case studies; focus on more detailed WWRs in a smaller range, by allowing smaller steps for WWR parameters, more detailed optima may be found; include the effect of installation efficiency, as this will affect the primary energy demand; assessing the effect of on-site energy production such as PV-panels on the building shape and WWR, as increasing the building envelope might not increase the net energy demand of buildings if more energy can be produced.    

optimisation
Building shape
Energy demand
Grasshopper
modeFrontier
Honeybee
daylight entrance

http://resolver.tudelft.nl/uuid:bbdf4ff9-2cff-4756-a59f-33fa49ed4dc0

Student theses

master thesis

© 2020 Bo Dorresteijn