Entry for:The Peer Prize for Climate
In this modern era, low-powered technologies and devices in the urban environment operate in every area of human activity. The multitude of low-energy applications extend from wireless sensors, data loggers, transmitters and other small-scale electronics. These devices function in the microWatt-milliWatt power range and will play a significant role in the future of smart cities. In this light, the development and integration of low-energy harvesters suitable for such applications is indispensable. This study aims to investigate the potential built-environment integration and energy-harvesting capabilities of the Wind-Induced Flutter Energy Harvester (WIFEH) – a microgenerator aimed to provide energy for low-powered applications.
The methodology was two fold and presents both the experimental investigation of the WIFEH inside a wind tunnel and a case study utilising Computational Fluid Dynamics (CFD) modelling of a building which was integrated with a WIFEH system. The experiments tested the WIFEH subjected to various wind tunnel airflow velocities ranging from 2.3 to 10 m/s to evaluate the induced electromotive force generation capability of the energy harvester. The CFD simulation used a gable-roof type building model with a 27˚ pitch obtained from the literature. The atmospheric boundary layer (ABL) flow was used for the simulation of the approach wind. The research investigates the effect of various wind speeds and WIFEH locations on the performance of the device giving insight on the potential for integration of the harvester into the built environment.
When subjected to airflow of 2.3 m/s the energy harvester was able to generate an RMS voltage of 3 V, peak-to-peak voltage of 8.72 V and short-circuit current of 1 mA. With an increase of wind velocity to 5 m/s and subsequent membrane retensioning, the RMS and peak-to-peak voltages and short-circuit current also increase to 4.88 V, 18.2 V, and 3.75 mA, respectively. For the CFD modelling integrating the WIFEH into a building, the apex of the roof of the building yielded the highest power output for the device due to flow speed-up maximisation in this region. This location produced the largest power output under the 45˚ angle of approach, generating an estimated 62.4 mW of power through wind that accelerated in device position from 4.7 m/s to 6.2 m/s. For 0° wind direction, airflows in facade edges were the fastest at 5.4 m/s indicating a 15% speed-up along the edges of the building. For incident wind velocity of 10 m/s, wind in the apex accelerated up to approximately 14.4 m/s which is a 37.5% speed-up at the particular height. This occurred for an oncoming wind 30˚ relative to the building facade.
The Wind-Induced Flutter Energy Harvester is valuable for low-energy wind harvesting in the built environment due to its low cost and modularity. The following points encapsulate the important findings of the study:
· With increasing airflow speed came increases in open-circuit voltage and short-circuit current produced by the WIFEH. Regular sinusoidal waveform voltage signals were observed through a digital oscilloscope for wind tunnel airflow speeds of 2.3 m/s and 5 m/s with the belt retensioned.
· The simulation used a gable-roof type building model with a 27˚ pitch obtained from the literature. The overall highest power output comes from location R3 – the apex of the building – with an estimated voltage output of 15.2 V, resulting from wind speed that accelerated up to approximately 14.4 m/s, approximately 37.5% speed-up at the particular height. This occurred for an incoming wind 30˚ relative to the building facade.
· Optimum installation of the WIFEH devices translates to prioritising the roof and the trailing edges of the building to yield the highest possible power generation, depending on wind conditions, while avoiding the leading edge or centres of surfaces.
5. Future ideas/collaborators needed to further research?
Future studies on the installation of the WIFEH will include field tests within specific target urban environment settings like underneath bridges, alongside motorways and on building facades. Further work will also cover simulations using transient models that will also involve non-uniform flow conditions. Prospective investigations on the impact of varying shapes of the subject building and different locations of the device located on these new surfaces will also be conducted. Further investigations will also include the impact of surrounding buildings on the performance of the device. This will feature the shape of surrounding buildings, distance and positioning, etc. Field tests will also be conducted to evaluate device performance in actual conditions and assess other factors such as noise, visual and related parameters. Economic analysis of the integration of the WIFEH in buildings will be carried out and compared with more established low-energy generation technologies
6. Please share a link to your paper
The author is a current PhD candidate for the Energy 2050 group in the University of Sheffield, United Kingdom. He is interested in new and emerging wind energy innovations. A big science advocate,...
Round: Open Peer Vote
Category: Student Prize