Demonstration of a pyroelectric wireless temperature sensor

Abstract

Energy generation systems operating at high temperatures are becoming increasing dependent on real-time measurements to enhance the overall performance. Since most sensors in energy systems are exposed to high temperature, high pressure, or corrosive environments where wiring is not desirable, harsh environment temperature sensing is preferred to be measured wirelessly. In this study, Pb(Zr0.52Ti0.48)O3 (PZT) pyroelectric ceramic was used to develop a wireless temperature sensor. An electromagnet was built with a set number of loops of wire, length, and radius. A PZT ceramic exposed to a heating source to induce a rate of temperature change with time. Generated current from the PZT due to experiencing a rate of temperature change with time was then supplied to the electromagnet to generate a magnetic field. The magnetic field was measured remotely with a milligaussmeter. The electromagnet was first characterized by measuring the magnetic field at different distances from the edge of the electromagnet along its axis. The milligaussmeter was able to detect the magnetic field generated by PZT pyroelectric ceramics at the specified distances from the electromagnet. A PZT sensor with a thickness of 0.1 cm was tested for use in a wireless temperature measurement configuration. Due to the non-linear pyroelectric response of PZT, the temperature dependent pyroelectric coefficient of PZT was also measured with a dynamic pyroelectric measurement technique in the temperature range from room temperature to 122 °C. The temperature dependent pyroelectric coefficient of PZT was found to increase from −40 × 10−5 C m−2 °C to −71.84 × 10−5 C m−2 °C. The PZT sensor was then tested for wireless temperature measurement applications at 100 °C, 150 °C, and 200 °C, and showed a maximum 10% deviation from baseline measurements.