Thermal Energy Harvesting Using Pyroelectric Ceramics

 (De Gruyter) – While energy harvesting systems have drawn increased attention during the previous years most research has focused on mechanical energy harvesting using piezoelectric ceramics. Little is known of the experimental capabilities to harvest thermal energy at different temperature ranges and the impact that the temperature range has on the energy conversion efficiency. A majority of piezoelectric ceramics are pyroelectric in nature thus enabling them to couple energy generation between thermal and electrical domains.

The authors created a Lithium Niobate (LNB) thermal energy harvesting device for high temperature applications.

They developed a custom testing setup developed to test the LNB sample temperatures up to 225 °C. The pyroelectric coefficient of the material was characterized at different temperature ranges. The pyroelectric coefficient was found to increase with temperature, with a maximum value of −196 μC·m−2 °C−1. Power output of the sample was also characterized at different temperature ranges. A maximum value of over 20.5 μW was found when cycling the sample between 75 °C and 100 °C. Meanwhile, a maximum value of 14.8 μW was found in the 125 °C to 150 °C range. A peak value of 255 nW was found when cycling the sample in the 200 °C to 225 °C range.

The feasibility of energy harvesting capabilities of a pyroelectric material capable of withstanding elevated temperatures was demonstrated. Decreasing power output at temperatures up to 225 °C was found due to a change in the impedance of the sample, as well as a lower pyroelectric power conversion efficiency at high temperatures due to an increase in the specific heat of the material.

Despite a decrease in the pyroelectric power conversion efficiency was observed, results demonstrated the feasibility of harvesting a considerable amount of energy at different temperatures using LiNbO3 piezoelectric ceramics.

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Edited for Content and Length by Dr. Matthew A. Hood.

The  full article can be found at De Gruyter in the journal of Energy Harvesting and Systems.

DOI: 10.1515/ehs-2018-0002

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