Author: Heemin Noh (Korea Railroad Research Institute) - Rail transportation systems are widely recognized as environmentally friendly modes of mobility, primarily due to their low carbon emissions and high energy efficiency compared to other forms of transport. However, to align with the increasing demand for sustainable and low-impact energy solutions, research efforts have been actively progressing to further enhance the energy efficiency of railway systems. These efforts span various domains including regenerative braking, optimized train control, lightweight materials, and energy harvesting technologies.
In this presentation, we introduce a novel approach that utilizes an unconventional energy source—acoustic noise generated during high-speed train operation. While noise is typically considered a pollutant, this study treats it as a viable energy resource. Specifically, the focus of this research is on harvesting acoustic energy from high-speed train noise through the use of a Helmholtz resonator and piezoelectric generators. Although high-speed trains generate substantial low-frequency noise (50–200 Hz) during operation, particularly in the inter-car, passenger cabin, and driver cabin sections, this energy source has rarely been utilized in the railway field.
To address this opportunity, we designed a Helmholtz resonator tuned to 174 Hz, matching the dominant frequency of measured noise inside the train. Experimental validation was conducted using numerical simulations and physical measurements to assess the vibration and energy output of various piezoelectric elements mounted on the resonator. Results showed that a peak voltage of 0.7 V could be generated under 100 dB noise conditions, demonstrating the feasibility of powering low-consumption sensors and electronic devices.
This research confirms the viability of acoustic energy harvesting in railways and its potential use with low-power electronics for future autonomous monitoring systems, eliminating the need for wired power.