The reliability and economic analysis of rainwater harvesting system for commercial building with large rooftop area

Abstract The problem of water shortages faced by many countries including the country that having sufficient water source needs to be provided a practical engineering solution. The reliability analysis of rainwater harvesting system (RWHS) installed at the commercial building of AEON Taman Universiti located in Johor Barhu city of Malaysia was based on the rainfall pattern, rainwater use and rainwater storage tank. The economic analysis using the net present value (NPV), return on investment (ROI) and benefit-cost ratio (BCR) was performed to assess the optimal management of RWHS installed during the period of construction and retrofitted after the operation of commercial building. The results showed that the balance of water supply and demand is reliable to implement the RWHS and the optimal management of 1000-m3 RWHS tank installed during the construction could be more promising than that retrofitted after the operation of AEON Taman Universiti commercial building. The operation of RWHS installed during the construction of building is obviously more feasible due to the values of NPV, ROI and BCR tend to be high. The reliability and economic analysis of RWHS installed during construction and that retrofitted after operation of commercial building demonstrated the benefit of RWHS installation will contribute to the future of building design for achieving an effective water management.