2017 - Daylight Symposium
"Parametric daylight facade optimization methodology" by Alejandro Dieguez
Speakers
Alejandro Pacheco Diéguez (SE)
Architect,
White Arkitekter
Lecture from the 7th VELUX Daylight Symposium “Healthy & climate-friendly architecture– from knowledge to practice” that took place in Berlin on 3-4 May 2017. For more information visit http://thedaylightsite.com
”Parametric daylight façade optimization methodology” by Alejandro Dieguez. Daylight is proven to have beneficial effects on health and mood. It is especially important to provide healthcare buildings with good daylighting to contribute to the physical and psychological well-being of patients and staff. Good daylighting can sometimes be in conflict with thermal comfort or a reduced space heating/cooling energy use. This is especially true when dealing with high ratings in environmental certification where the level of demand is quite high in all aspects.
A methodology was developed by the Digital Sustainable Design group of White Arkitekter (Stockholm) to balance these conflicting interests to ensure good daylight performance from the first stages of the building design. This methodology was successfully applied as a pilot to the design of two hospital buildings in the center of Malmö (Sweden). Both buildings are required to comply with the highest level (GOLD) of the environmental certification system Miljöbyggnad. The buildings’ openings should be sized and distributed throughout the facades to provide good daylighting to concerned spaces. On the other hand, their size should be limited to avoid excessive solar heat gains and transmission and infiltration heat losses in winter.
The study consisted on a parametric optimization of the window and shading sizes for each of the façade modules on the buildings to attain good daylight levels without jeopardizing thermal comfort and the energy performance of the building. Automatic or manual solar shading devices, preferably externally placed, are often required to limit the solar heat gains during the cooling season. These devices should cover enough glazed area so as to avoid overheating problems. On the other hand, shading devices produce an important decrease in daylight levels when drawn. This should be avoided as much as possible by limiting their size. The optimization methodology uses a specially developed iterative algorithm that includes daylight and peak solar radiation simulations.
It was developed using the graphical algorithm editor Grasshopper. The study should be applied in early stage, when only the general shape of the building has been sketched. Both the façade design and the interior layout are part of the parameters studied. The methodology is structured in two phases. Facade modules with variable window sizes were predesigned for each of the buildings. Phase one informs of the maximum room depth (MRD) that can potentially comply with the daylight requirement considering all facade modules and the largest possible window size. This information can be used to fit the activities that require daylighting in areas with a good daylight access. Once the preliminary room depths have been determined phase two determines the optimal window and shading areas for each façade module to comply with the daylight and solar heat gains requirements specified for each project.
Alejandro Pacheco Diéguez works as a Digital Sustainable Design Specialist at White arkitekter in Stockholm. Alejandro has a Master’s in Architecture from Universidad de Sevilla (Spain) and a Master’s in Environmental Building Design from LTH (Lund, Sweden). In Lund, he specialised in daylight optimisation through collaboration on research projects in that area. Soon after, he started working as an environmental specialist at the BAU architecture studio in Stockholm, where he developed his skills with daylight simulations and gained experience using parametric tools. He currently works at White arkitekter, where he combines his environmental design expertise with the use of parametric tools. His main fields of interest include building design and city planning optimisation.
