_applied sciences_  
_Article_  
**Intelligent Model for the Reliability of the Non-Intrusive**  
**Continuous Sensors Used for the Detection of Fouling-Layer**  
**in Heat Exchanger System**  
**[PERSON] 1,2,*(c), [PERSON] 2(c) and [PERSON] 3(c)**  
1 Department of Mechanical Engineering, University of Port Harcourt, East-West Road Port Harcourt,  
Choba 500272, Nigeria  
2 Faculty of Engineering and Built Environment, University of Johannesburg, Johannesburg 2006, South Africa  
3 Department of Business Administration, University of Gothenburg, 405 30 Gothenburg, Sweden  
* Correspondence: [PERSON]  
**Abstract:** Faults in this sensor must be detected on time to ensure the functionality of the entire system's architecture and to maintain system balance, which will keep false positive rates low during the system's operational period. False positives reduce diagnostic confidence and necessitate unnecessary and costly mitigation actions, lowering system productivity. It is on this basis that this study proposes a clustering model algorithm (K-mean clustering) to investigate and manage the reliability and performance of the sensors. The results from the implementation of the K-mean clustering method show that the running of the algorithm fits the model correctly, both for the training of the dataset and for the prediction of the cluster in each of the datasets considered. A reasonable grouping was found for the two and three clusters considered, which are represented by the colors (blue, orange, and green). These colors indicate the fault state, non-fault state, normal state, and abnormal state of the non-intrusive continuous sensor. The simulated results show the fault state in the blue region and the non-fault state in the orange region for the two clusters, while the normal state is in the blue region and the abnormal state is in the orange and green regions for the three clusters considered. non-intrusive continuous sensors; heat exchanger system; K-mean clustering; reliability and performance  
**1. Introduction**  
Heat exchangers are one of the important systems used in the process and power generation industries [1]. It is used for transferring heat from one medium to another, where such a medium could be in the form of a gas, a liquid, or a combination of both. The media could be separated in some applications by a solid wall, or it could be completely mixed in other applications; however, they are aimed at improving the energy efficiency of such applications by transferring heat from systems where it is not needed to systems where it will be more useful [2]. \"For example, waste heat in the exhaust of an electricity-generating gas turbine can be transferred via a heat exchanger to boil water to drive a steam turbine and generate electricity\". The most common type of heat exchanger is a car radiator, where the cooling process of the car engine is optimized to make it more efficient. Heat exchangers work because heat naturally flows from higher temperatures to lower temperatures. Therefore, if a hot fluid and a cold fluid are separated by a heat-conducting surface, heat can be transferred from the hot fluid to the cold fluid [3]. Several types of heat exchangers have been developed for use in steam power generation plants, chemical processing plants, petroleum refinery plants, buildings, heating and air conditioning systems, natural gas processing, and space heating and refrigeration units [4]. Despite the many benefits of the heat exchanger system application in the processing and power generation industries, it is often challenged by the formation of unwanted material deposits on the heat transfer surfaces. These deposited materials, which are in the form of scale, algae, suspended solids, and insoluble salts on the internal or external surfaces of heat exchangers [5], are sometimes called \"heat exchanger fouling,\" and they occur during process heating or cooling [6].