2 - SHAPE
Bioclimatic building design improved through performance optimization
Bioclimatic design aims at ensuring the functionality of the building, such as visual and thermal comfort, by taking advantage of the environmental sources of the local climate. Due to the significant energy problems worldwide, it is a topic of increasing interest in architectural design. The basic idea behind bioclimatic design is to incorporate passive (natural) systems into the buildings, which utilize environmental sources in order to cover housing needs, such as thermal or lighting comfort. In most cases, such solutions derive mainly from smart, practical ideas, rather than scientific rigor. Thus, they could probably be further improved by employing optimization methods. The efficiency of the proposed methodologies will be illustrated via three real-life examples.
WP5 - Bioclimatic building design improved through performance optimization [Months: 4-36]
Bioclimatic design may refer to various disciplines, such as Computational Fluid Dynamics (CFD) for modelling the wind and simplified ray methods for modelling the light. As a consequence, those models that can be attributed a wellposed mathematical formulation are more suitable for gradient-based optimization algorithms, while models based on heuristics necessitate the use of derivative-free algorithms. Therefore, since the optimization approach to follow is casedependent, we propose to show the utility of applying optimization techniques in bioclimatic design through the study of three representative test cases : Task 5.1: Facade optimization for optimal lighting [2-8] The first test-case refers to a former warehouse having transformed into a five-storey office building. In order for the building meet specific design requirements, both the bearing concrete structure and the building envelope were totally re-structured to address sustainability issues and building regulations for the new use. An important modification of the building envelope was the construction of a sunshade system. Its elements have been designed with such an orientation that the lighting in the interior and the view provide a natural feeling. We aim at optimizing the shape of the sunshades and the angle of the elements and their blinds. At a first step, the qualitative criterion of "natural sense" of the lighting shall be translated into quantitative data. Then, we need to define the tool through which the data will be automatically obtained. The last step, before performing the optimization, will be to connect the optimizer with the CAD software used in the design and the analysis software for the lighting, so that the iterative approach is executed automatically. Task 5.2: Optimal design of wind deflectors  In the second test case, we search to optimize the wind deflectors applied in the so-called "House of the WINDS", in Santorini, Greece. The shell of the building was perforated in order to turn the wind force into a means of protection against its own force. Funnels formed within the mass of the casing deflect the wind entering them, thus creating a protective wind curtain in front of the corresponding openings, so that the shell is resistant without being hermetically sealed. The shape of the funnels has been determined via a combination of intuition and a trial-and-error approach. The first step towards optimizing the shape of the funnels is to decide a CFD problem that models with sufficient accuracy the wind load, while not being too complicated to use in an optimization procedure. Depending on the difficulty of the model and of the geometry, the team will decide if it is preferable to use a CFD software or to develop a code for the particular problem. Finally, the team will agree on the formulation of the optimization problem and different scenario regarding the wind speed and direction will be defined. Task 5.3: Optimal design of walls against sand accumulation and wind The last test case refers to a so-called Sand Constraint project. The goal is to optimally design a wall that prevents the accumulation of sand by wind and waves on a sea-shore sidewalk and adjacent public spaces. Such a construction has been designed for Artemis, Greece. The protection wall needs to have multiple functionality; mitigate the sand-blast by deflecting the flow of the lower air layers hitting against the walls; reduce the velocity of the higher layers, while at the same time function as a temporary sand accumulator (the waves deposit and withdraw the sand). For the optimal design of the walls, same steps as in Task 5.2 will be followed.