The performance and risk assessment of R290 in a 13 kW air source heat pump

Currently, with the growing concerns about global climate change, R290 has been considered as a competitive next generation refrigerant used in the air source heat pump (ASHP). However, the flammable characteristics of R290 prevented its wide application in the large ASHP system. This paper mainly contributed to the application of R290 in an ASHP with a nominal heating capacity of 13 kW. Firstly, the performance of R290 in the ASHP was measured. By optimizing the equipment of the refrigeration system, the charge of R290 in this ASHP is reduced to 1.3 kg which meet the requirements of the EN378-1 (2016), and the coefficient of performance (COP) of this R290 ASHP could reach 2.8 and 3.27 respectively in the rated refrigerating and heating conditions, which could meet the corresponding Chinese national standards. Then the experimental investigation on the risk after a R290 leakage from the ASHP was presented for the first time. The R290 concentration distribution in the ASHP surrounding and internal area was measured when the leakage occurred in different scenarios. The results showed that the combustible zone will continuously appear in the inside area of the ASHP during the whole leakage process. But in the outside area, it only appeared in the region where around the ASHP and extremely close to the ground. Finally, some suggestions according to the experimental results were presented to improve the safety design of the R290 ASHP.