# Mitigating Electrochemical Effects in Resistive Frost-Detection Sensors
## 5 Conclusions
While the pulsed DC method still led to some decrease in resistivity, the magnitude of this change was relatively small compared to the highly dynamic nature of frost formation, defrosting, and condensation in evaporators. As a result, this introduces a minimal and likely acceptable margin of error, with a low impact on frost detection accuracy. Previous studies have shown that frost detection remains feasible even with continuous voltage measurement, despite its susceptibility to electrochemical effects. The resistive sensor offers a cost-effective and scalable solution for frost detection in refrigeration systems, enhancing the efficiency of demand defrost systems by reducing unnecessary defect cycles. The findings of this study contribute to the development of energy-efficient refrigeration technologies, as frost sensing ensures defrost cycles are activated only when necessary, minimizing the energy consumption associated with unnecessary defrosting operations while maintaining temperature stability. By improving the reliability and accuracy of frost detection, the proposed sensor can further optimize defrosting processes, reducing waste and enhancing energy efficiency in cold chain logistics. Future studies could explore the use of noble metals to mitigate some of the adverse effects of electrolysis, as they do not release ions into the water during oxidation reactions. Additionally, integrating noble metals would have a minimal impact on sensor costs for the developed sensors. For example, platinum has a density of 21.45 g/cm\({}^{3}\) and reached a 5-year price peak of EUR 34.56 on 6 February 2021 [25], yet the raw material cost per small electrode would still be below EUR 1. However, pulsed DC excitation remains essential, as even with non-reactive noble metals, electrolysis would still occur. The presence of dissolved OH\({}^{-}\) and H\({}^{+}\) ions, along with the production of H\({}_{2}\) and O\({}_{2}\) gases accumulating near the electrodes destabilizes resistance readings. These effects make the continuous voltage approach unsuitable for long-term use in frost detection systems, regardless of the electrode material used. Further work should examine the integration of resistive sensors into existing refrigeration control systems for automated frost detection and defrost initiation. The sensor's simple electrical interface allows for direct compatibility with common microcontroller- or PLC-based platforms. Machine learning algorithms could enhance the sensor's ability to differentiate between frost, water, and air under complex operating conditions. Conceptualization, M.L.A. ; methodology, M.L.A., P.D.G. and P.D.S. ; software, M.L.A. ; validation, P.D.S. ; formal analysis, M.L.A., P.D.G. and P.D.S. ; investigation, M.L.A., P.D.G. and P.D.S. ; resources, P.D.G. ; data curation, M.L.A. ; writing--original draft preparation, M.L.A. ; writing--review and editing, P.D.G. and P.D.S. ; supervision, P.D.S. ; funding acquisition, P.D.G. All authors have read and agreed to the published version of the manuscript. The authors would like to express their gratitude to Fundacao para a Ciencia e Tecnologia (FCT) and C-MAST (Centre for Mechanical and Aerospace Science and Technologies) for their support in the form of funding, under the project UIDB/00151/2020. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The raw data supporting the conclusions of this article will be made available by the authors on request. **Acknowledgments:** The authors acknowledge the support provided by LTlecS (Laboratory of Innovation and Technologies for Sustainability) ([[https://litecs.ubi.pt/en/](https://litecs.ubi.pt/en/)]([https://litecs.ubi.pt/en/](https://litecs.ubi.pt/en/)) accessed on 10 March 2025). **Conflicts of Interest:** The authors declare no conflicts of interest.