Numerical analysis of the integration of wind turbines into the design of the built environment

The effect of wind distribution on the architectural domain of the Bahrain Trade Centre was numerically analysed using Computational Fluid Dynamics (CFD). Using the numerical data, the power generation potential of the building integrated wind turbines was determined in response to the prevailing wind direction. Simulating a reference wind speed of 6 m/s, the findings from the study quantified an estimate power generation of 6.4 kW indicating a capacity factor of 2.9% for the computational model. At the windward side of the building, it was observed that the layers of turbulence intensified in inverse proportion to the height of the building with an average value of 0.45 J/kg. The air velocity was found to gradually increase in direct proportion to the elevation with the turbine located at higher altitude receiving maximum exposure to incoming wind. This study highlighted the potential of using advanced computational fluid dynamics in order to factor wind into the design of any architectural environment

Design and Aerodynamic Investigation of Dynamic Architecture

The effect of the spacing between adjacent building floors on the wind distribution and turbulence intensity was analysed using computational fluid dynamics in this study. Five computational models were created with floor spacing ranging from 0.8 m (benchmark) to 1.6 m. The three-dimensional Reynolds-Averaged Navier–Stokes equations along with the momentum and continuity equations were solved using the FLUENT code for obtaining the velocity and pressure field. Simulating a reference wind speed of 5.5 m/s, the findings from the study quantified that at a floor spacing of 1.6 m, the overall wind speed augmentation was 39 % which was much higher than the benchmark model (floor spacing = 0.8 m) indicating an amplification in wind speed of approximately 27 %. In addition, the results indicated a gradual reduction in turbulence kinetic energy by up to 53 % when the floor spacing was increased from 0.8 to 1.6 m. Although the concept was to integrate wind turbines into the building fabric, this study is limited to the assessment of the airflow inside the spaces of building floors which can be potentially harnessed by a vertical axis wind turbine. The findings of this work have indicated that there is a potential for integration which will lead on to future research in this area

Editorial [to] Themed issue on sustainability in energy and buildings, part 1

This themed issue includes the selected papers from the proceedings of the seventh International Conference on Sustainability and Energy in Buildings 2015 (SEB15), which was successfully held in the vibrant city of Lisbon, Portugal and was organised by the Universidade Nova de Lisbon (New University of Lisbon) in partnership with KES International. Annually, the conference brings together researchers and government and industry professionals to discuss the future of energy in buildings, neighbourhoods and cities from a theoretical, practical, implementation and simulation perspective

Wind tunnel and CFD study of the natural ventilation performance of a commercial multi-directional wind tower

Abstract Scaled wind tunnel testing and Computational Fluid Dynamics (CFD) analysis were conducted to investigate the natural ventilation performance of a commercial multi-directional wind tower. The 1:10 scaled model of the wind tower was connected to the test room to investigate the velocity and pressure patterns inside the micro-climate. The tests were conducted at various wind speeds in the range of 0.5–5 m/s and various incidence angles, ranging from 0° to 90°. Extensive smoke visualisation experiments were conducted to further analyse the detailed airflow structure within the wind tower and also inside the test room. An accurate geometrical representation of the wind tunnel test set-up was recreated in the numerical modelling. Care was taken to generate a high-quality grid, specify consistent boundary conditions and compare the simulation results with detailed wind tunnel measurements. The results indicated that the wind tower was capable of providing the recommended supply rates at external wind speeds as low as 2 m/s for the considered test configuration. In order to examine the performance quantitatively, the indoor airflow rate, supply and extract rates, external airflow and pressure coefficients were also measured. The CFD simulations were generally in good agreement (0–20%) with the wind tunnel measurements. Moreover, the smoke visualisation test showed the capability of CFD in replicating the air flow distribution inside the wind tower and also the test room

Evaluation of airflow and thermal comfort in buildings ventilated with wind catchers: Simulation of conditions in Yazd City, Iran

The usage of passive cooling systems such as wind catchers can reduce the energy usage in buildings and provide natural ventilation and comfort to its occupants, particularly in hot and dry regions of Iran and neighboring countries where it was traditionally used. The purpose of this study was to investigate the airflow and thermal comfort in six different designs of wind catchers using computational fluid dynamics (CFD) technique. Simulations of airflow in the wind catcher and the building were done under steady state and turbulent flow regime with boundary conditions based on typical conditions found in Yazd city, Iran. Several commonly used turbulence models were evaluated to assess the accuracy of the simulation. First, the proposed CFD model was validated through comparison of wind tunnel data available in the literature, and then the model was used for design purposes. It was found that the k − ω turbulence model can accurately predict the airflow velocity in the range of parameters studied. The design and performance of wind catcher were evaluated based on the thermal comfort levels using the Center for the Built Environment (CBE) thermal comfort tool and numerical data. Width and height of the wind catcher were varied in the simulations and optimal values were determined. It was found that varying the width of the wind catcher had the greatest impact on the airflow speed and distribution inside the room. Reducing the width from 2.5 m to 2 m showed that airflow velocity in the middle area was increased up to 34%. While reducing the width from 2 m to 1.5 m showed an entirely different flow pattern inside the building and also increase airflow speed in the middle area up to 50%. The addition of curved wall at the bottom of the inlet channel showed that it could increase the airflow speed of the inflow stream, however, it also caused the airflow to be directed towards the lower levels of the room and very large rotating flows in the upper levels. Finally, the results showed that the wind catcher may be optimized for improving comfort for various climates using the tools presented in this work

Something about the Mechanical Moment of Inertia

In this study, the relations to determining mass moments of inertia (mechanical) for different mass and mechanical inertia corresponding to geometric shapes, objects and profiles are explored. The formulas for calculating the mass moments of inertia (mechanical) for various bodies (various geometrical forms), to certain major axis indicated (as the axis of calculation) are presented. The total mass M of the body is used to determine the mass moment of inertia (mechanical). In the first part of the paper, an original method for determining the mass moment of inertia (mechanical) of the flywheel is presented. Mass moment of inertia (the whole mechanism) reduced at the crank (reduced to the element leader) consists in a constant mass inertia moment and one variable, to which we may include an additional mass moment of inertia flywheel, which aims to reduce the degree of unevenness of the mechanism and the default machine. The more the mass moment of inertia of the flywheel is increased the more the unevenness decreased and dynamic functioning of the mechanism is improved. Engineering optimization of these values can be realized through new relationships presented on the second paragraph of the article. Determining of the mass moment of inertia of the flywheel with the new method proposed is also based on the total kinetic energy conservation