Uncertainty analysis and field implementation of a fault detection method for residential HVAC systems

The vast majority of fault detection and diagnosis (FDD) methods for air conditioning systems are developed for packaged commercial systems. This paper presents a method for obtaining key operating parameters for air conditioning systems (airflow rate, cooling capacity, system efficiency, and refrigerant mass flow) in a way that is well-suited for the residential sector. The method relies on an air-side capacity estimate and will be compared and contrasted with a more traditional method that relies on a refrigerant-side capacity estimate. These methods are compared in terms of their sensitivity to input parameters, their uncertainty in the outputs, and their sensor requirements. The proposed air-side sensing method requires fewer sensors and has a significant advantage for residential split systems because it requires no outdoor unit sensors. The air-side sensing method is then successfully implemented on a field operating residential system. The experimental results show that the proposed method is sensitive to manually introduced airflow faults.