Numerical analysis on multi directional wind tower with thermo syphon effect

Abstract

Recently, natural ventilation techniques such as wind towers were increasingly being used in buildings for increasing the supply of fresh air and reducing the HVAC consumption. Typical operation of wind towers is generally limited to summer seasons as the outdoor air is too cold to be introduced into spaces for the majority of the year. Computational Fluid Dynamics (CFD) analysis was conducted to investigate the natural ventilation performance of a commercial multi-directional wind tower with water filled heat pipes. Wind towers are normally shutdown for the sake of avoiding indoor heating energy losses during winter months. Consequently, the concentration of pollutants has seen to rise above the guideline levels, which can lead to ill health. To improve the year-round capabilities of wind towers, a heat recovery system utilising the combination of heat pipes and heat sink was incorporated into a multidirectional wind tower. This study investigates the potential of this concept through the use of numerical analysis for validation. The three dimensional Reynolds-Averaged Navier Stokes (RANS) equations along with momentum, continuity and energy equations were solved using the commercial FLUENT code for velocity and pressure field simulations. The findings showed that the wind tower with heat pipes was capable of meeting the required ventilation rates above an inlet air velocity of 1 m/s. CFD study displayed that the proposed wind catcher was capable of reducing heat load during winter.