Air compression systems used in manufacturing operations are constantly monitored by sensors that detect air pressures drops and help prevent leaks which could halt production and cost money. At present, these sensors are either battery driven or connected up by complex technical wiring. This often makes it difficult or even impossible to install sensors in places that are hard to reach.
Fraunhofer researchers from Stuttgart have developed a new technology that enables the production of energy-autonomous and thus low-maintenance sensors. “Our system is eminently suitable for sensors in pneumatic plants as we can convert the kinetic energy from air or water into electricity,” explains Jose Israel Ramirez, who is doing research on this topic at the TEG.
“The fluid energy transducer generates electricity in the microwatt or milliwatt range. This is sufficient to supply cyclically operating sensors with enough energy to read out and transmit the relevant data.”
The fluid-electricity conversion takes place in a fixed housing, through which the medium is fed on a course similar to that of blood circulating in the heart. The Coanda effect causes the constant stream of fluid to oscillate. This produces a periodic pressure fluctuation in the feedback branches, which are coupled to piezoceramics. “The piezoceramics convert the fluidic energy into electricity,” says group leader Axel Bindle, summarising the principle.
"This fluidic conversion is simple and cost efficient.
“We have the advantage that both air and water can be used to generate energy. What’s more, we don’t have any movable parts in our system. The structure can be produced in simple processes, and that saves costs. The new technique can be applied to any system in which a fluid or a gas is guided through a fixed geometry — in supply networks or in medical engineering, for example.
“Our objective is to be able to provide currently battery-driven devices, such as water meters, with an autonomous supply of energy in the near future, resulting in completely independent systems,” says Bindel.
