(269g) Application of Magnetic Phase Transition in Energy Harvesting Wireless Temperature Sensors

In recent years, many industries are showing great interest in sustainable societies, with concepts such as cyber-physical systems (CPS). In doing so, energy efficiency becomes a crucial point of concern. From the initial data acquisition to the data storage and communication component of a CPS, maintaining a sensible energy efficiency is of paramount importance for a sustainable society. Energy harvesting, where electricity is made from low-quality energy sources, is promising in this regard. Yet a common difficulty with many energy harvesters is that the energy output simply does not meet the energy demand in the system. With that said, it is nonetheless promising to be able to harvest the energy necessary for operation in the components of a CPS. Thus, an investigation in the energy efficiency of energy harvesters for sensor devices is a key topic in order to realise a sustainable society.

In this research, the authors proposed a novel energy harvesting wireless sensor with possible application for a temperature data acquisition device. This can for instance be for monitoring body temperature, which is not only quite important for various key components of our society, such as public health, but also is a highly quantifiable measure for monitoring health. The proposed device utilises the magnetic properties of materials as the working principle in order to produce electricity from low quality subject heat while simultaneously monitoring the temperature. When a magnetic material approaches its Curie Temperature, a magnetic phase change occurs, causing a corresponding magnetic flux change. By incorporating electromagnetic induction with solenoids, this magnetic flux change could be measured as voltage. Thus, this phenomenon can be applied for an energy harvesting temperature sensor in the near range of a material’s Curie Temperature, as the voltage reading is representative of the magnetic flux change and thus the material temperature. Thus, with an apt material, the device has the potential to operate as a temperature sensor. In this research, the authors analyse the applicability of the proposed device for a large-scale temperature sensor, in terms of its quality as a temperature sensor and its energy harvesting capabilities. Namely, an investigation on the fundamental magnetic properties of the sensor probe material in question and the electromagnetic induction capabilities are conducted.