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In-line Hydropower Harnessing Devices

Introduction

Online monitoring instruments and wireless data transmitters are important tools for the management of a modern water distribution network, and these new facilities need a reliable, convenient and cost-effective means of power supply.

WSD collaborated with the Hong Kong Polytechnic University (PolyU) on the development of an inline micro hydroelectric generating system for use in confined conditions in end of 2009, which is a renewable energy device that uses green energy tapped from surplus pressure in water mains, in order to cope with the Water Intelligent Network (WIN)’s requirements on real-time monitoring and control of the water distribution network.

The device is designed to generate electric power from water flow in pipes for operating the underground instruments, such as flowmeters installed at remote locations and under congested urban streets, where other sources of power supply are not readily available, with the merits of no needing regular replacement of disposable batteries and helps reduce carbon emission.

Merits of Application

All in all, the merits of using IHHDs for WIN projects are as follows:-

1. Use of green energy tapped from surplus pressure in water distribution network for powering up underground monitoring and data transmission equipment;
2. Easy to install inside confined underground waste detection chambers;
3. Robust design to withstand fluctuating water flow velocity (3.3 m/s or even higher, intermittently);
4. Helps reducing carbon emission;
5. Poses no threat to contamination of fresh water supply;
6. Very useful for locations with difficulties in supplying 220V grid-power from power company;
7. Eliminates the need for construction of power supply kiosks, which alleviates the congestion of urban areas; and
8. Enabling real-time monitoring without the need of regular replacement of disposable batteries around once every 2-3 years.

Operating Principle

The core part of the system is an inline hydroelectric generator. Its basic operating principle is to use a highly efficient inline turbine to transform the surplus pressure of water flowing in a water pipe and transform it into electric power for storage or direct consumption.

When water flows through the pipe, the turbine drives a micro generator to generate electricity of around 20W under an average water flow velocity of around 1.5 m/s.

System Design

The new generation of the IHHD works “as a system” to power the monitoring and transmission equipment for the smart water network.

It is composed of various components, namely, an integrated turbine-generator for harnessing surplus water power in the pipeline for converting it into zero-carbon electricity, a short pipe for swift installation to a pipeline, a charger and battery system for dealing with diurnal flow characteristics of the fresh water distribution network, and a diversion load for dissipating surplus electricity and preventing over-speeding of the integrated turbine-generator unit.

Way Forward

We are now seeking to incorporate the IHHDs in new development projects (New Development Areas (NDAs) and new housing developments) as a smart initiative.

In the meanwhile, we are developing with the 5^th generation of IHHD to work in Lower Flow Conditions (LFC).