Vortex shedding induced energy harvesting from piezoelectric materials in heating, ventilation and air conditioning flows

Abstract

A cantilevered piezoelectric beam is excited in a heating, ventilation and air conditioning (HVAC) flow. This excitation is amplified by the interactions between (a) an aerodynamic fin attached at the end of the piezoelectric cantilever and (b) the vortex shedding downstream from a bluff body placed in the air flow ahead of the fin/cantilever assembly. The positioning of small weights along the fin enables tuning of the energy harvester to operate at resonance for flow velocities from 2 to 5 m s−1, which are characteristic of HVAC ducts. In a 15 cm diameter air duct, power generation of 200 μW for a flow speed of 2.5 m s−1 and power generation of 3 mW for a flow speed of 5 m s−1 was achieved. These power outputs are sufficient to power a wireless sensor node for HVAC monitoring systems or other sensors for smart building technology.