Visual Req Calculation Tool for Green Building Evaluation in Taiwan

The concept of a “green building” was first introduced to Taiwan in 1999, and began to develop regulations for the design and evaluation of energy-saving buildings. The Ratio of Equivalent Transparency (Req) is a basic index for assessing whether a building is energy-efficient. Req is the ratio of the area of total building envelope and the area of envelope equivalent transparency. Calculation of Req requires not simply the consideration of natural factors such as building location, direction, ambient lighting and sunshine, but also and physical factors such as material, structure, ventilation and sunshade. Furthermore, Req is considered particularly applicable due to the ubiquity of terraced houses in Taiwan, given the country’s high population density. In this study, the correction factor to include the effect of party walls is added into the formula of Req calculation to prevent distortions to the area calculation of the building envelope. Current practices in Taiwan of manually calculating Req render the results prone to error, and are also time-consuming. To address these issues, this research developed a visual Req calculation tool based on a 3D environment. This system provides users with various visualization tools to view the status and Req results of the building project. Furthermore, object-oriented modeling and parametric design can shorten the time taken to look-up tables and simplify the process of Req calculation, and also help to reduce computation time and errors.