Combined electromagnetic and piezoelectric energy harvesting from low-speed fluid flows for remote monitoring

The studentship is part of the UK’s Centre of Doctoral Training in Metamaterials (XM2) based in the Departments of Physics and Engineering on the Streatham Campus in Exeter. Its aim is to undertake world-leading research, while training scientists and engineers with the relevant research skills and knowledge, and professional attributes for industry and academia.

This project explores the application of piezoelectric composite and magnetic materials for energy harvesting from fluid flows for remote monitoring sensors.

Wireless sensor networks are the very need of the government as well as industries to monitor remote environment and assets. However, replacing the depleted batteries, which are usually the only energy supply for those sensors, brings a significant cost and sometimes is even impossible when a large number of sensors are deployed. This has servery hindered the implementation of wireless sensor networks for remote monitoring [1].

Energy harvesting has the potential to provide a sustainable power source for wireless sensors by converting ambient energy sources to usable electricity, and thus enabling maintenance-free wireless sensor networks. Fluid (liquid) flows in the ambient environment are potentially a sustainable energy source for wireless sensors [2]. While on the large scale hydroelectric power plant has been used for a long period, energy harvesting from low-speed fluid flows in small scale for small electronic devices is still challenging because of the reduced transducer efficiency and reduced kinetic energy available, particularly when the transducer size is restricted by the application. Both piezoelectric (PE) and electromagnetic (EM) transducers work well for high-speed fluid flows. However, for low-speed flows, they are unable to generate enough power [3-4]. This has limited the application of fluid flows as an energy source for remote sensors.

To address this challenge, the project aims to develop a novel energy harvesting technology from low-speed fluid flows with enough power output to supply remote sensors. Unlike previous approaches where a single transduction mechanism was used, this project will combine the EM and PE transduction mechanisms in one hybrid energy harvester to increase the electric power. New magnetic field configurations and mechanical transmissions will be explored to increase the efficiency of the EM transduction with low-speed flows. The turbulence and vortices due to the EM transducer will actuate the PE transducer, which will use novel piezoelectric composites (e.g. auxetic piezoelectric composite developed in our lab [5]) to increase its power density. The design of the energy harvester will take systematic considerations on the fluid dynamics, actuating methods and transduction mechanisms to ensure an optimised overall efficiency.

The cohort and community training approach of XM2 will provide the PhD candidate with a dynamic research environment with an opportunity to exchange knowledge and ideas with other students, and access to essential training and courses provided by the XM2. Given the multi-disciplinary nature of this project, the student will particularly benefit from the multi-disciplinary research environment and supervision team.

The project industrial partner is AutoNaut Ltd which produces wave propelled unmanned surface vessel for long endurance operation in Southern Ocean or Arctic and requires energy harvesting to power communication systems.

[1] SujeshaSudevalayam et al. IEEE Communications Survey &Tutorials, Vol.13, No.3, 2011
[2] Faisal Shaikh et al. Renewable and Sustainable Energy Reviews, 55 (2016) 1041-1054
[3] D Hoffmann et al. Journal of Physics: Conference Series 476 (2013) 012104
[4] Eric Molino-Minero-Re et al. Instrumentation and Measurement Technology Conference, 2012 IEEE International, 624-627
[5] Qiang Li et al. AIP Advances, 7, 015104 (2017)