Resistivity-based sensing and heating element for surface thermal mapping

Temperature control is critical in numerous industrial applications, and can typically be achieved via the coordinated use of heating and cooling systems in conjunction with feedback control loops. While point-based temperature measurements can be readily obtained using robust sensing technologies, such as thermocouples, achieving a complete surface temperature mapping presents significantly greater challenges. To overcome this difficulty, conventional approaches often rely on line-of-sight methodologies, such as thermal imaging, which are difficult to implement in certain industrial environments where physical access to the target surface is limited. This paper presents a novel layer-based compact device, termed the Heating and Thermal-sensing Element (HTE), which integrates both temperature sensing and heating capabilities within a single structure. The HTE is fabricated using plasma spray technology, and its measurement principle is based on surface temperature evaluation via the change in electrical resistance of a metallic material constituting a resistive heater. By patterning the resistive material into a grid-like configuration, a complex resistance network can be formed, enabling temperature monitoring at multiple discrete locations across the surface. The approach leverages the use of an inversion algorithm to infer the temperature distribution from an appropriate set of resistance measurements. This paper details the fabrication, development, testing, and functionality demonstration of the HTE, with emphasis on its temperature-sensing capability. For the 2 × 2 configuration, the HTE device achieved a temperature mapping accuracy within 3 °C of infrared-camera measurements, with a total response time of approximately 0.55 s for twelve-zone mapping. The 4 × 4 configuration captured the main temperature-distribution trends but required filtering to reduce local fluctuations and improve the reconstructed temperature maps. These results confirm the feasibility of the proposed approach and demonstrate the potential of the HTE for advanced, non-line-of-sight thermal management in industrial applications.