Low-Grade Waste Vibration Energy Recovery from Hong Kong Franchised Buses

Abstract

Vibration characterization in moving franchised buses has been performed. Considering the frequency spectrum of vertical acceleration, two distinct vibration peaks at 2.2 and 14 Hz were observed. The root-mean-square acceleration peak values were 5.59×10⁻⁶ and 1.95×10⁻⁶ g²/Hz, where g is the acceleration due to gravity. Based on the experimental results of vibration frequency characteristics, a conventional piezoelectric cantilever energy harvester with natural frequency tuned at 14 Hz was constructed. This paper presents the application of piezoelectric energy harvester to obtain the low-grade waste vibration energy from Hong Kong franchised buses. Ten different bus routes were selected for the energy harvesting. On average, statistical data showed that for buses traveling from one terminus to another, by using the cantilever piezoelectric energy harvesting technique, the feasible power generated from bus vibration was around 90 μW.

Keywords:

• Piezoelectric energy harvesting
• Vibration-to-electric energy conversion
• Piezoelectric cantilever
• Vibration frequency characterization of motor vehicles
• Hong Kong