A Computational Fluid Dynamics (CFD) Study on Enhancing Green Building Performance in Dubai, UAE Using Diffuser Augmented Wind Turbines (DAWT)

Abstract

By incorporating a Diffuser around the rotor to form a Diffuser Augmented Wind Turbine (DAWT), a conventional wind turbines’ performance can be significantly improved. The diffuser is able to funnel and accelerate incident air flow to the rotor thereby driving it for a higher power extraction threshold for better control and continuous periods of operation. A steady-state Computational Fluid Dynamics (CFD) study was carried out in ANSYS Fluent on a three-bladed roof-mounted DAWT on a section of the Heriot-Watt University building located in Dubai, UAE. The results displayed that the diffuser significantly improved performance on the equivalent bare wind turbine used as a baseline model. The DAWT outperformed the Horizontal Axis Wind Turbine (HAWT) with Concentrator as it induced the largest pressure drop across the rotor and the largest wind speed. The results show improved aerodynamic capabilities as wind speeds were significantly increased and better distributed across the rotor in the DAWT; it achieved a 53.8% increase in wind speed compared to the benchmark HAWT (bare wind turbine) which had 0.6 m/s at rotor. The HAWT w. Concentrator achieved a 35.1% increase on the benchmark. The maximum power augmentation achieved was 2.5 at speed of 1.3 m/s at the rotor for the DAWT. The results agree well with the work of Ohya and Karasudani (2010) where they achieved augmentation ratios between 2 and 5 and the work of Wang and Chen (2008) where an augmentation ratio of 2.2 was achieved for DAWT’s. The conclusions for this study provide an example of improving building performance with renewable wind technology. In accordance with the UAE’s 2030 vision to encourage “sustainability, infrastructure capacity, community planning and quality of life”, the present work hopes to contribute to the mandate.