Browsing Department of Mechanical Engineering & the Built Environment by Subjects
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Computational and Wind Tunnel Study of the Performance of a Multi-Directional Wind Tower with Heat Transfer Devices. International Conference on Applied EnergyThe aim of this work was to investigate the performance of a multi-directional wind tower integrated with heat transfer devices (HTD) using Computational Fluid Dynamics (CFD) and wind tunnel analysis. An experimental scale model was created using 3D printing. The scale model was tested in a closed-loop wind tunnel to validate the CFD data. Numerical results of the supply airflow were compared with experimental data. Good agreement was observed between both methods of analysis. Smoke visualisation test was conducted to analyse the air flow pattern in the test room attached underneath it. Results have indicated that the achieved indoor air speed was reduced by up to 17% following the integration of the cylindrical HTD. The effect of varying the number of HTD on the system's thermal performance were investigated. The work highlighted the potential of integrating HTD into wind towers in reducing the air temperature. The technology presented here is subject to a UK patent application (PCT/GB2014/052263).
Numerical Analysis of a Wind Catcher Assisted Passive Cooling TechnologyBuildings are responsible for almost 40% of the world energy usage. Heating Ventilation and Air-Conditioning (HVAC) systems consume more than 60% of the total energy use of buildings. Clearly any technology that reduces HVAC consumption will have a dramatic effect on the energy performance of the building. Natural ventilation offers the opportunity to eliminate the mechanical requirements of HVAC systems by using the natural driving forces of external wind and buoyancy effect. One technology, which incorporates both wind and buoyancy driven forces, is the wind catcher. Wind catchers are natural ventilation systems based on the design of traditional architecture. Though the movement of air caused by the wind catcher will lead to a cooling sensation for occupants, the high air temperature in hot climates will result in little cooling to occupants. In order to maximise the properties of cooling by wind catchers, heat transfer devices were incorporated into the design to reduce the supply air temperature. The aim of this work was to investigate the performance of a wind catcher integrated with heat transfer devices using numerical modelling and wind tunnel experiment. The wind catcher model was incorporated to a building, representing a small room of 15 people. Care was taken to generate a high-quality CFD grid and specify consistent boundary conditions. An experimental model was created using 3D printing and tested in a wind tunnel. Qualitative and quantitative wind tunnel measurements were compared with the CFD data and good correlation was observed. The study highlighted the potential of the proposed wind catcher in reducing the air temperature by up to 12 K and supplying the required fresh air rates.
Numerical and Experimental Analysis of a Multi-Directional Wind Tower Integrated with Vertically-Arranged Heat Transfer Devices (VHTD).The aim of this work was to investigate the performance of a multi-directional wind tower integrated with vertically-arranged heat transfer devices (VHTD) using Computational Fluid Dynamics (CFD) and wind tunnel analysis. An experimental scale model was created using 3D printing. The scale model was tested in a uniform flow closed-loop wind tunnel to validate the CFD data. Numerical results of the supply airflow were compared with experimental data. Good agreement was observed between both methods of analysis. The Grid Convergence Method (GCI) method was used to estimate the uncertainty due to discretisation. Results have indicated that the achieved indoor air speed was reduced by 8–17% following the integration of the VHTD. The integration of VHTD had a positive effect on cooling performance of the wind tower, it reduced the incoming fresh air by up to 12 K. The effect of varying the number of VHTD rows (1–3 rows) on the system’s performance were also investigated. Additional simulations were also conducted to investigate the effect of atmospheric boundary layer (ABL) flows on the wind tower ventilation performance and also compare it with the results of uniform flow wind tunnel study.