From flow to voltage: design and optimization of a water flow turbine-based energy harvester
File(s)
Author(s)
Lepipas, Georgios
Type
Thesis
Abstract
Energy harvesting is a crucial technology to enable autonomous sensing. The aim of
this thesis is to explore and develop minimally invasive water flow energy harvesting
solutions for self-powered sensing applications.
As a result, in this thesis, an experimental study of a miniature turbine-based water
flow energy harvester designed to provide power to wireless sensors within water
pipes is reported. The device comprises a Savonius-type turbine and a radial flux
permanent magnet electromagnetic generator. The two are magnetically coupled so
that, while the turbine is submerged in the water flow, the generator operates in air.
The device is cylindrical with a diameter of 0.8 cm and a length of 7.2 cm and, when
inserted through a hole in a pipe wall so that only the turbine protrudes into the flow,
it presents a cross-sectional area to the flow of only 1.25 cm2. Manufacturing was
achieved through a blend of conventional machining methods, laser cutting, rapid
prototyping, and the utilization of flexible printed circuit board technology for the
generator stator. To ensure low friction and minimize cut in speed, ceramic ball
bearings were employed. The prototype can function effectively at water velocities
as low as 0.5 m/s, generating electrical power within the range of 125 μW to 5.1 mW
when subjected to flow speeds between 0.5 and 2 m/s. A maximum overall efficiency
of 2.2% is achieved, when the water speed is 0.8 m/s. Performance curves derived
from experimental testing of the turbine for a range of rotor designs, obtained on a
water flow rig, are presented and discussed.
this thesis is to explore and develop minimally invasive water flow energy harvesting
solutions for self-powered sensing applications.
As a result, in this thesis, an experimental study of a miniature turbine-based water
flow energy harvester designed to provide power to wireless sensors within water
pipes is reported. The device comprises a Savonius-type turbine and a radial flux
permanent magnet electromagnetic generator. The two are magnetically coupled so
that, while the turbine is submerged in the water flow, the generator operates in air.
The device is cylindrical with a diameter of 0.8 cm and a length of 7.2 cm and, when
inserted through a hole in a pipe wall so that only the turbine protrudes into the flow,
it presents a cross-sectional area to the flow of only 1.25 cm2. Manufacturing was
achieved through a blend of conventional machining methods, laser cutting, rapid
prototyping, and the utilization of flexible printed circuit board technology for the
generator stator. To ensure low friction and minimize cut in speed, ceramic ball
bearings were employed. The prototype can function effectively at water velocities
as low as 0.5 m/s, generating electrical power within the range of 125 μW to 5.1 mW
when subjected to flow speeds between 0.5 and 2 m/s. A maximum overall efficiency
of 2.2% is achieved, when the water speed is 0.8 m/s. Performance curves derived
from experimental testing of the turbine for a range of rotor designs, obtained on a
water flow rig, are presented and discussed.
Version
Open Access
Date Issued
2025-03-23
Date Awarded
01/11/2025
License URL
Advisor
Holmes, Andrew
Publisher Department
Department of Electrical and Electronic Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)