Vibrations from Forth Bridge and Queensferry Crossing could be harvested and turned into electrical power
Unused energy caused by vibrations on the likes of the Forth Bridge and Queensferry Crossing could soon be harvested and converted into electrical power in a major new project led by an Edinburgh university.
Traffic and wind cause low frequency vibrations to ripple through bridge building materials such as steel and concrete, but the energy normally travels away from its source before dissipating.Academics at Heriot-Watt University alongside colleagues from Georgia State and the Georgia Institute of Technology in the US, intend to capture and recycle this untapped source by using the principles of physics.The team has received £340,000 from the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation, and $443,000 (£322,500) from the National Science Foundation (NSF) to research and develop a revolutionary vibro-impact energy harvesting device.Dr Daniil Yurchenko from Heriot-Watt University, has created a prototype called a "vibrant pack energy harvester" that can be fitted at multiple locations on a bridge. The autonomous devices, measuring around 5 to 10cm in length, do not require wiring to an electrical power source and are relatively cheap to manufacture.They work by holding a small ball housed within a tube that rolls back and forth as the device absorbs low frequency vibrations. As the ball moves, it impacts on non-conductive materials, known as dielectric membranes, located at either end of the tube. When the membrane is stretched, a brief electrical charge is applied but once it returns to its undeformed state, the generated excessive electrical charge can be harvested.This electrical energy is stored in a battery and used to power a sensor capable of monitoring the structural integrity of a bridge. Engineers can then record multiple measurements, such as vibrations, traffic load, wind and temperature, all at the same time but without the need for specialist infrastructure to be installed at significant cost.Dr Yurchenko from the School of Engineering and Physical Sciences at Heriot-Watt University, said that whilethe technology has been tried in wave energy, nothing has been done on this scale before.He said: "What we are doing is creating a more efficient and cost-effective solution by harvesting energy that would otherwise be lost. It’s something that has never been done before in this way."It’s a technology that can be used on any bridge anywhere in the world. There are plenty of places where these devices can be fitted to a bridge structure such as on cables, on the pillars, on the side of the bridge deck, there really aren’t any limits."The biggest problem in energy harvesting is that the absolute amount of energy produced by a typical device is very small due to the low available level of vibrations. In fact, for the past 100 years scientists have been fighting adverse vibrations to ensure that bridges are safe. So, through this work we will try to optimise the performance of our vibro impact energy harvesting device."Dr Yurchenko said the Forth Bridge and Queensferry Crossing would be ideal candidates for the technology in the future. The team is working alongside Wenzel Consult, an independent company that specialises in bridge sensor technology in Austria and Turkey.