Two-sided windcatcher in low wind speed environment

Abstract

Global warming is a major threat and is mainly caused by emission of greenhouse gases. The building construction sector or buildings are accountable for about 40% of total greenhouse gases due to energy consumption. The application of air conditioning systems is reported to reach 70% of this energy consumption. In contrast, natural ventilation systems such as windcatcher are a promising passive cooling alternative that not only improve indoor air quality (IAQ) and thermal comfort but also reduce energy consumption. However, the efficiency of windcatcher is hindered by two factors: air short-circuit phenomenon and low ambient wind speed. The aim of this research is to develop a new windcatcher design that addresses both problems by integration of wing wall and installation of a new device called anti-short circuit device (ASCD). Based on review of literature, wing wall and ASCD can enhance the performance of windcatcher in low wind speed. To achieve this aim, two methods namely wind tunnel testing and simulation using computational fluid dynamics (CFD) were explored. The results showed that the difference between the CFD and experimental results was within the acceptable range. Integration of wing wall and ASCD to the windcatcher improved the IAQ factors such as air flow rate, air change rate and air velocity. It was observed that the ventilation performance of the new design in 45o wind incident angle was better than the 0o wind incident angle. In conclusion, this study has proven that the new design can effectively be implemented to improve the ventilation and IAQ.