Investigation of a double-PCM-based thermoelectric energy-harvesting device using temperature fluctuations in an ambient environment

Energy-harvesting devices, consisting of thermoelectric modules and phase change materials (PCMs), can extract energy from the ambient environment for the self-power supply of many small electronic devices such as wireless sensors. However, due to the distinct temperature ranges of various seasons in different places, these devices' power generation performance may be seriously impaired. In this paper, a new double-PCM-based thermoelectric energy-harvesting device based on temperature fluctuations in the ambient environment is proposed to improve device performance. A double-PCM-based device has been built and tested in an environment with a large temperature range (0-40 degrees C) for three days. Experimental results show that the average output power of the double-PCM-based thermoelectric energy-harvesting device under matched load resistance outperforms that of the single-PCM device by 35.8%. A one-dimensional unsteady heat transfer model is established to describe the temperature variation of PCMs. The influence of phase change is considered through variations in PCMs' specific heat capacity. This work demonstrates that the proposed double-PCM-based thermoelectric energy-harvesting device performs better over a large temperature range and is more suitable for small electronic devices operating at different times and in different places. (C) 2020 Elsevier Ltd. All rights reserved.