Overall thermal transfer value of naturally ventilated double skin facade in Malaysia

Abstract

As one of the many paths to achieve a sustainable built environment, the Malaysia uniform building bye-law with the new amendment stipulates that the OTTV of a building envelope with a total air-conditioned area exceeding 4000 m2 should not exceed 50 W/m2. Although, the existing formulae provided for calculating OTTV is only applicable to a traditional single skin façade (SSF) building. Therefore, this paper seeks to investigate and evaluate how the natural ventilation in the cavity of a naturally ventilated double skin façade (NVDSF) will impact the OTTV of a building integrated with this façade typology. To achieve this goal, a hypothetical base-case was designed to represent a typical commercial building in Kuala Lumpur, Malaysia. The calculated OTTV value of the base case is compared with that of the same building integrated with naturally ventilated cavity using dynamic simulation software (EnergyPlus/DesignBuilder) tool. The result indicates that the annual heat transferred through the east orientation of the building is higher than all other orientations and by integrating a naturally ventilated cavity on all orientations would reduce the cooling load over traditional single skin building by a range between 46% and 84%. However, the cost implication of investing in buildings with this kind of façade require more exploration for a better understanding on the return of investment in Malaysia context.