Scientists create self-powered fluid sensors

Researchers of the Fraunhofer Technology Development Group TEG have successfully created a fluidic energy transducer that creates electricity from fluid motion in the surrounding air or water.

The technology enables the production of energy-autonomous, low-maintenance sensors, removing the need for batteries or wiring.

“Our system is eminently suitable for sensors in pneumatic plants, as we can convert the kinetic energy from air or water into electricity,” said José Israel Ramirez, one of the researchers.

“The fluidic 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. This produces a periodic pressure fluctuation in the feedback branches, which are coupled to piezoceramics.

“The piezoceramics convert the fluidic energy into electricity,” said group leader Axel Bindel.

“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 technique can be applied to any system in which a fluid or a gas is guided through a fixed geometry — in supply networks or 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,” said Bindel.

The TEG researchers will be presenting a prototype of the fluid transducer at the annual electronica trade fair in Munich, Germany.