Parametric analysis of the wind-driven ventilation potential of buildings with rectangular layout (original) (raw)
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IAQVEC, 2019
The negative impact of the building industry has brought a critical emphasis on the performance-related tools and processes of architectural design. The integration of design and performance simulation has the potential to extend the decision-making capabilities of the architects. Amongst a number of performance parameters, wind-related measures are generally problematic for the design phase, due to the computational cost of predicting wind behaviour, the complexity of the urban context and the constantly changing airflow patterns. In this respect, this paper proposes the preliminary exploration of a design method towards integrating Computational Fluid Dynamics (CFD) coupled with energy modelling and parametric design tools for the wind-related design acts. As building performance is regarded as a design problem that necessitates a designerly point of view as much as a technical perspective, the method aims at providing visual, generative and accurate feedback regarding its potential to facilitate the architect's designerly integration to the process and to provide a flexible design environment. The preliminary quantitative analysis conducted through a case study indicates the preliminary data flow through the design process. 1. Introduction Over the last decades, computational design tools have been increasingly used to support building design with building performance simulation (BPS) tools. BPS tools are usually regarded as analytical that are used at the end of the design process, which leaves the generation-evaluation loop incomplete. For such problems, integrated platforms that allow the simultaneous use of design and BPS tools have been developed [1], which has a potential to improve the quality and precision of the design process with visual and rapid feedback [2]. However, the wind-related design processes stand problematic due to the unpredictability of airflow patterns. Regarding the benefits of the wind such as fresh air, passive cooling and natural ventilation-a direct impact on the indoor environmental quality and occupant's comfort-the problem must be addressed by means of computational support from a designerly point of view. In this regard, this research problematizes the lack of integration between the airflow simulation and design tools and focuses on the integration of computational fluid dynamics (CFD) simulation. The purpose of this research is the preliminary exploration of the integrated design processes supported by simulation tools. To this end, this paper implements a computational design method and presents the preliminary results on the use of CFD-integrated design process to support decision-making in architectural design. A case study is conducted focusing on zone mean air temperature and ventilation sensible heat loss for a simple building in Istanbul, which has a hot-humid climate with the temperatures that reach its extreme in August with 34.6 ℃ [12]. In Istanbul, the vast majority of the building stock is not conditioned, which puts an emphasis on the effective use of natural ventilation for passive cooling.
Better Natural Ventilation Design for Single Sided Apartments Utilising Computational Fluid Dynamics
International Journal of Architectural Engineering Technology, 2020
Wind-driven natural cross ventilation to many single-aspect apartments can be achieved via building indentations and façade articulation. The ventilation rate of these apartments will rely on pressures differences between openings caused by approaching wind pressure, local wind climate and interaction with the surrounding built environment and external pressure gradients on the building indentations or any other facades articulation and their potential driving force on natural ventilation. Detailed simulation methods are therefore required to consider all above mentioned parameters and provide internal and external airflow information to the design team to allow for design modifications or refinement where required to provide robust natural cross ventilation for such apartments. This study assesses the above parameters for a proposed development, designed with recesses and slots to enhance natural cross ventilation in single-sided apartments, and presents a reliable procedure to advise on compliance with national and/or international design guidelines utilising an advanced combined outdoor-indoor Computational Fluid Flow (CFD) analysis integrated with localized weather data for the project site.
The wind tower is an ancient technique used since the time of Feraoun (1300 AC) until today for natural ventilation in the arid Middle East region including Iraq and Iran without any energy consumption ensuring thermal comfort and considerable energy efficiency by comparing it with HVAC systems (Heating, Ventilation and AirConditioning) widely used in these areas. Two mechanisms are used in the natural ventilation: buoyancy caused by the temperature difference and the wind pressure forces on the envelope of the ventilated structure. Δp is the pressure difference resulting from the external pressure caused by the interaction wind-structure and the internal pressure which cause an airflow inside building driving by Δp and finally the air leave the building through building openings (doors, windows, etc.). In order to create maximum pressure difference, the wind tower geometry (windward side) is questioned. Four aerodynamic shapes are studied: square, circular, triangular and U. The results show that the circular and triangular models have external and internal pressures much higher than the square and U model. This new aerodynamic geometries are more appropriate to create maximum Δp than rectangular tower. These results confirm the importance of Computational Wind Engineering CWE in the study of natural ventilation potential of this technique especially in windy arid regions such as the South of Algeria. CFD techniques have become increasingly essential as an aid to decision in modern design of natural ventilation systems.