THE IMPACT OF ROOF SIZE ON THE DIMENSIONS AND EFFICIENCY OF RAINWATER COLLECTION TANKS USING TANGKI NAHRIM 2.0

The phenomenon of global warming, coupled with the growing global population, has a direct and significant influence on the demand for water worldwide. In Malaysia, the use of drinkable water is significantly higher compared to other nations, and the primary supply of drinkable water is predominantly surface water. Rainwater harvesting is a widely adopted alternative for water resources globally. Despite Malaysia's copious rainfall, rainwater collection remains unpopular in the country. Houses of varying sizes have corresponding variations in roof sizes, which in turn necessitate variable sizes of rainwater tanks. This study employed the use of Tangki NAHRIM 2.0 (TN2), a web tool, to calculate the most suitable tank capacity for a rainwater collecting system. The analysis was conducted for five distinct roof sizes, with the focus on meeting non-potable water requirements. The TN2 simulation employs a daily water balance model that utilizes rainfall data from an integrated database, following the yield-after-spillage (YAS) protocol. The ideal capacities for rainwater tanks for five distinct roof sizes range from 2.6 m3 to 3.8 m3. These tanks exhibit water-saving efficiency values ranging from 59% to 76.2% and storage efficiency values ranging from 30.9% to 53.9%. A larger tank capacity provides greater water-saving efficiency, but at the expense of reduced storage efficiency. The product will be valuable for the implementation of RWHS in residential buildings.