Computational analysis of a heat transfer device integrated wind tower system for hot climate

The purpose of this study is to integrate heat transfer devices in a wind tower to meet the internal comfort criteria in extreme external condtions. Computational Fluid Dynamics (CFD) was used to develop a numerical model of a wind tower system and simulate the air flow pattern around and through the device to the test room. Results have indicated that the average internal airflow rate was reduced following the integration of the vertical and horizontal heat transfer device configuration, reductions of 4.11% and 8.21% was obtained respectively. The work also compared the thermal performance of the passive ventilation device incorporating traditional evaporative cooling and heat transfer devices. The proposed cooling system was capable of reducing the air temperatures by 12-15K

Numerical investigation of the integration of heat transfer devices into a wind tower

Increasing focus on reducing energy consumption has raised public awareness of renewable energy resources, particularly the integration of natural ventilation devices in buildings such as wind tower systems. Wind towers have traditionally been used in Middle Eastern architecture for many centuries to provide natural ventilation and thermal comfort. The purpose of this study is to integrate heat transfer devices in a wind tower to meet the internal comfort criteria in extreme external condtions. Heat transfer devices were installed inside the passive terminal of the wind tower unit, highlighting the potential to achieve minimal restriction in the external air flow stream while ensuring maximum contact time, thus optimzing the cooling duty of the device. A geometrical representation of a full scale wind tower configuration, micro-climate and macro-climate was modeled. Computational Fluid Dynamics (CFD) was used to develop a numerical model of a new wind tower system and simulate the air flow pattern and pressure coefficients around and through the wind tower to the test room. Results have indicated that the average internal airflow rate was reduced following the integration of the vertical and horizontal heat transfer device configuration, reductions of 4.11 % and 8.21 % was obtained from the achieved numerical models. The work compared the effect of evaporative cooling and heat transfer devices on the thermal performance of the passive ventilation device. The proposed cooling system was capable of reducing the air temperatures by 12-15 K, depending on the configuration and operating conditions

The influence of structural morphology on the efficiency of building integrated wind turbines (BIWT)

A numerical investigation was carried out to determine the impact of structural morphology on the power generation capacity of building-integrated wind turbines. The performance of the turbines was analysed using the specifications of the Bahrain Trade Centre which was taken as the benchmark model, the results of which were compared against triangular, square and circular cross-sections of the same building. The three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations along with the momentum and continuity equations were solved for obtaining the velocity and pressure field. 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 benchmark model. The square and circular configurations however determined greater capacity factors of 12.2 % and 19.9 %, recording an estimated power production capability of 26.9 kW and 35.1 kW and confirming the largest extraction of the incoming wind stream. The optimum cross-sectional configuration for installing wind turbines in high-rise buildings was the circular orientation as the average wind speed at the wind turbines was accelerated by 0.3 m/s resulting in an overall augmentation of 5 %. The results from this study therefore highlighted that circular building morphology is the most viable building orientation, particularly suited to regions with a dominant prevailing wind direction. - See more at: http://aimspress.com/aimse/ch/reader/view_abstract.aspx?file_no=20140302&flag=1#sthash.X2u7QIPC.dpu

Integration and Application of Passive Cooling Within a Wind Tower

Increasing emphasis on reducing power consumption has raised public awareness of natural and renewable energy resources, particularly the integration of passive cooling systems in buildings such as wind towers. Wind towers have been in existence in various forms for centuries as a non-mechanical means of providing indoor ventilation. In hot conditions where there is a relatively low difference between internal and external temperatures, the cooling capabilities of wind towers which depend mainly on the structure design itself are inadequate. Therefore it is essential to cool the air in order to reduce the building heat load and improve the thermal comfort of its occupants during the summer months. The aim of this work was to incorporate heat transfer devices in a wind tower to meet the internal comfort criteria in extreme external conditions. Heat transfer devices were installed inside the passive terminal of the wind tower unit, highlighting the potential to achieve minimal restriction in the external air flow stream while ensuring maximum contact time, thus optimising the cooling duty of the device. Computational Fluid Dynamics (CFD) modelling and experimental wind tunnel testing were conducted to investigate the performance of a wind tower system incorporating the heat transfer device arrangement. Results have indicated that the achieved indoor air speed was reduced by 28 – 52 % following the integration of the heat transfer device configurations. Furthermore, the study concluded that the proposed cooling system was capable of reducing the air temperatures by up to 12 K, depending on the configuration and operating conditions. Good agreement was observed between the CFD simulation and the experimental results

Advancement of natural ventilation technologies for sustainable development

Heating Ventilation and Air Conditioning (HVAC) systems account for up to 60% of domestic buildings energy consumption [U.S Dept. of Energy, (2009)]. Natural ventilation offers the opportunity to eliminate the mechanical requirements of HVAC systems by using the natural driving forces of external wind and the buoyancy effect from internal heat dissipation. A wind tower was used in traditional architecture originating from the Middle East and captured air at a higher velocity and delivered it through cool sinks to the buildings occupants. Commercial Wind towers have been available in the United Kingdom (UK) for the last forty years; recent rising energy costs have seen their implementation into new and existing building increase. This research details the technological developments of the wind tower system in the UK and Qatar and discusses the barriers to implementation and the on-going research in this field

Numerical investigation of the integration of heat transfer devices into wind towers

The purpose of this study is to incorporate heat transfer devices inside the passive terminal of a wind tower unit, highlighting the potential to achieve minimal restriction in the external air flow stream while ensuring maximum contact time, thus optimising the cooling duty of the device. Computational Fluid Dynamics (CFD) was used to develop a numerical model of a wind tower system and simulate the air flow pattern around and through the device to the test room. Results have indicated that the average internal airflow rate was reduced following the integration of the vertical and horizontal heat transfer device configuration, reductions of 4.11 % and 8.21 % was obtained respectively. Furthermore, the proposed cooling system was capable of reducing the air temperatures by up to 15 K. The technology presented here is subject to IP protection under the QNRF funding guidelines