Harnessing energy from rainwater downpipe

Abstract

The purpose of this project aims to study and compare the difference in electrical energy that can be generated with and without siphonic drainage in a downpipe from an HDB building, to assist households with the rising electricity costs. Siphonic drainage proves to be a significant advancement in the field of rainwater management, most notably with the improvement of flood prevention on roofs.

Siphonic drainage is designed to prevent air from entering the rainwater downpipe, allowing it to be filled with water, leading to an increase in flowrate. The increase in flowrate is important for this project as it means that more energy can be generated due to the conservation of energy and kinetic energy.

Firstly, an ultrasonic flowmeter will be used and placed at 119B Kim Tian Rd to measure the rainwater flowrate during raining events. The expected energy generated from a mini hydro turbine will be calculated with the measured flowrate across 29 floors. Next, the same set of measured flowrate data will be sent to Wavin to simulate the expected flowrate with the presence of siphonic drainage. Lastly, the simulated flowrate data will be used to calculate the expected energy that can be generated from the mini hydro turbine as well.

Results obtained have shown that the energy generated without the siphonic drainage is 1.456 W and the energy generated with the siphonic drainage is 185.67 W. This implies that there is an increase of 10031.9% of energy generated with the integration of siphonic drainage. This further indicates that with the steady increase of rainfall over the years, more green energy can be generated, assisting households with the soaring energy prices.