Preliminary Study on Fault Detection in Gas Coolers for Transcritical CO2 Refrigeration Systems

Carbon dioxide is acknowledged to be the refrigerant for next generation supermarket refrigeration systems. However, a notable dearth of research exists in fault detection and diagnosis applied to transcritical CO2 supermarket refrigeration systems. This paper addresses this knowledge gap by conducting a preliminary study on the impact of fouling in the gas cooler air side on the system performance over 7 hours of a typical summer day in Washington DC. The investigation was based on a dynamic model of a transcritical CO2 supermarket refrigeration system and 3 fouling scenarios, i.e., mild, moderate, and severe scenario. A grey-box model was developed to estimate the UA-value of the gas cooler. The findings demonstrated that this approach can be effectively utilized to detect fouling scenarios. Moreover, it was observed that the fouling results in increase in the electricity bill by 7.9 % and by 40.5 % in the moderate and severe scenario, respectively.