Powering In-pipe Wireless Sensors Using Flexible Piezoelectric Micro-generators

This paper presents a new piezoelectric energy harvester that generates sufficient energy to power wireless sensor nodes autonomously. Multiple PVDF-foils are layered alternately with electrode foils and wound to a spool. Due to induced turbulence inside standard flow pipes the piezoelectric foils are forced to oscillate converting kinetic energy into mechanical stress thus generating electrical charge. The new multilayer spool design tackles the common disadvantages of similar harvesters related to low piezoelectric coefficients of Polyvinylidene-fluoride or brittleness of Lead-zirconate-titanate. Wind channel experiments to prove the feasibility of the concept result in a harvested output power of 0.54 μW at a wind velocity of 7 m/s. With efficient duty cycling of the sensor node 324 μWs of energy are available for data transmission. The presented harvester is proposed as a universal power supply for sensors inside pipe systems. All of the systems components are included inside the pipe allowing for a maintenance-free deployment of sensors in remote locations.