Characterization of Thermal Energy Harvesting Using Pyroelectric Ceramics at Elevated Temperatures

Abstract

Energy harvesting has drawn increasing attention due to the fast development of wireless sensors and devices. Most research has been focused on mechanical energy harvesting using piezoelectric ceramics; however, little is known on their experimental capabilities to harvest thermal energy at different temperature ranges and the impact that the temperature range has on the energy conversion efficiency. Majority of piezoelectric ceramics are pyroelectric in nature thus enabling them to couple energy between thermal and electrical domains. This paper demonstrates the use of Lithium Niobate (LNB) as a thermal energy harvesting device for high temperature applications. A custom testing setup was developed to test the LNB sample temperatures up to 225°C. Pyroelectric coefficient of the material was characterized at different temperature ranges. Pyroelectric coefficient was found to increase with temperature, with a maximum value of -196μC·m-2 °C-1. Power output of the sample was also characterized in different temperature ranges. A maximum value of over 20.5μW was found when cycling the sample between 75°C and 100°C. Meanwhile, a maximum value of 14.8μW was found in the 125°C to 150°C range. Finally, a peak value of 255nW was found when cycling the sample in the 200°C to 225°C range.