During rolling stock operation, various kinds of energy such as vibration, heat, and train-induced wind are dissipated. The amount of energy dissipation cannot be overlooked when a heavy railroad vehicle operates at high speed. Therefore, if the wasted energy is effectively harvested, it can be used to power components like low power sensor nodes. This study aims to review a method of collecting waste heat, caused by the axle bearing of bogie in a rolling stock. A thermoelectric module (TEM) was used to convert the temperature gradient between the surface of the axle bearing housing and the outdoor air into electric energy. In this study, the output performance by temperature difference in the TEM was lab-tested and maximized by computational fluid analysis of the cooling fins. The optimized thermoelectric energy harvesting system (TEHS) was designed and applied on a rolling stock to analyze the power-generating performance under operation. When the rolling stock was operated for approximately 57 min including an interval of maximum speed of 300 km/h, the maximum open circuit voltage was measured at approximately 0.4 V. Based on this study, the system is expected to be utilized as a self-powered independent monitoring system if applied to a low-power sensor node in the future.
Keywords: axle bearing; energy harvesting; railroad vehicle; rolling stock; thermoelectric generator.