Effect of refrigerant leakages on energy consumption of an electric heat pump for domestic air-conditioning

Refrigerant leakages in stationary air-conditioning and heat pumps represent almost the 50% of the amount of F-gas emissions declared by European Commission. Reducing leakages becomes crucially important because they cause both a high environmental impact and a decline of system performances. Typically, small leakages remain unidentified for a long period of time, causing a considerable long-term performance degradation of the machine. This paper deals with a mechanistic approach to simulate an air-to-air heat pump for domestic air conditioning, in different refrigerant loss rate scenarios, to evaluate the corresponding degradation of its seasonal performances. Results shows an average of 10% improvement of seasonal performances of the machine, with the employment of tools for fault detection and diagnosis (FDD) able to detect a refrigerant leakage through data collected by sensor mounted on the machine. Furthermore a 11% reduction of indirect contribute to global warming impact is achieved for small refrigerant leakages, whereas for larger leakages the direct emissions of CO2 become 65% lower.