Evaluation of a rainwater harvesting system in a single-family home in Palhoça/SC
DOI:
https://doi.org/10.46421/sispred.v4.7933Keywords:
Rainwater harvesting, non-potable water, residential buildings, NetunoAbstract
This study aimed to conduct a technical and economic analysis of a rainwater harvesting system in a single-family house located in Palhoça, Southern Brazil. The methodology comprised: (1) assessment of water consumption and end-uses through site visits and weekly records; (2) simulation using the Netuno software based on historical rainfall data from Brazilian National Institute of Meteorology (INMET); and (3) an economic feasibility analysis using local tariff structures and financial indicators such as Net Present Value (NPV) and Internal Rate of Return (IRR). The main end-uses of water were toilet flushing (19.95%), clothes washing (19.91%), and showers (15.90%). Two rainwater harvesting scenarios were evaluated: scenario 1 considered its use for toilet flushing, garden hoses, and a washing machine; scenario 2 limited the use to toilet flushing and garden hoses. The simulated rainwater harvesting system, considering a lower rainwater tank of 3,000 L and an upper tank of 500 L, resulted in a 35.6% reduction in potable water consumption. The financial analysis indicated that the investment was feasible in scenario 1, with a payback period of 55 months, a positive NPV, and an IRR higher than the Minimum Acceptable Rate of Return. It is concluded that the system is technically effective and economically advantageous, contributing to sustainability in the built environment.
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