Performance of Variable Design Configurations for Wind Driven Rain (WDR) Shading Device in Tropical Climate Selbin P.K., C.H. Lim, Seyedehzahra Mirrahimi, M. Alkhair, Elias Salleh, K. Sopian Solar Energy Research Institute (SERI) Universiti Kebangsaan Malaysia MALAYSIA E-mail: selbinpk@gmail.com , chinhaw.lim@gmail.com Abstract: - Wind-driven rain (WDR) or driving rain is rain that is given a horizontal velocity component by the wind. Wind driven rain research is important in building science especially in the tropical regions due to heavy rain fall. WDR is the most important moisture source affecting the performance of building facades and building interior space. This paper explored and analyzed on various rain shading design configurations for WDR in tropical climate. Computational fluid dynamics (CFD) method was used to simulate the 6 different rain shading design configurations. Based on the CFD flow visualization analysis, it was found that the optimum rain shading device was the louvers type for the tropical climate. Key-Words: - Wind-driven rain, building façade, tropical area, CFD. 1 Introduction Wind driven rain or WDR is an important research subject in building science. Semi-enclosed spaces in café shops, restaurants and other shopping outlets can suffer from rainwater penetration during heavy rain coupled with strong wind. WDR is the most important moisture source affecting the hygrothermal performance and durability of building facades. Consequences of its destructive properties can take many forms. Moisture accumulation in porous materials can lead to water penetration, frost damage, moisture induced salt migration, discoloration by efflorescence, structural cracking due to thermal and moisture gradients, to mention just a few. WDR impact and runoff is also responsible for the appearance of surface soiling patterns on facades that have become characteristic for so many of our buildings [2]. Without the presence of wind, rain drops would have fall vertically on a roof with eaves and it would be all that was needed to protect windows and other sensitive building elements in the wall from getting wet [3]. Until today there are many buildings which still remain vulnerable to wind-driven rain especially in the tropical regions. In addition, the WDR can also cause critical building problem like moisture-induced salt migration which may cause structural issues. 2 Objective The 3 main objectives for this study are as follows: a. To explore various design configurations for WDR shading device in tropical climate; b. To analyse the flow distribution of the variable design configurations of the WDR; c. To identify the optimum WDR shading configuration in tropical climate. 3 Problem Solution Research on WDR for building can be predicted using 2 main methods namely the semi-empirical WDR method and the numerical simulations method based on Computational fluid dynamics (CFD). Both methods require standard wind and rain input data for the calculations such as wind speed, wind direction and horizontal rainfall intensity [4]. The study covered 6 different types of WDR shading design configurations namely the “0.5m length overhang”, “1.0m length overhang”, “1.5m length overhang”, “2.0m length overhang”, “tilted overhang” and “louvers” type overhang. A semi- enclosed model of a corridor space was modelled and used as “base model” for all the 6 different WDR shading configurations. It was also used as a Computer Applications in Environmental Sciences and Renewable Energy ISBN: 978-960-474-370-4 114