Investigation of the practical method for enhancing the safety of R290 split type household air conditioner.

R290 (propane) has been chosen as the competitive alternative for R22 in split type household air conditioner (STHAC) because of its remarkable thermodynamic performance, environmental characteristics and economic efficiency. However, R290 is a flammable substance, thereby the promotion of R290 STHACs is hindered by its potential fire risk to the building resulting from leakage. At present, the most important measure to ensure the safety is to strictly limit the refrigerant charge by domestic and international standards, which will impact the R290 STHAC's heating performance. But in fact, when the leakage of R290 occur from a STHAC, the distribution of R290 in STHAC, and the leaking rate also will seriously affect the safety of the R290 STHAC. In this paper, a practical method of installing a solenoid valve near the capillary was presented, the refrigerant leaking rate in R290 STHAC was carried out through quasi-liquid nitrogen method (QLNM), and the R290 concentration in the room after leakage was also measured by detectors. Compared with the common STHAC, experimental results of leaking rate showed that after the installation of a solenoid valve, the R290 leaking rate and concentration in the room was obviously reduced, thereby the safety of the R290 STHACs was substantially improved.R290 (propane) has been chosen as the competitive alternative for R22 in split type household air conditioner (STHAC) because of its remarkable thermodynamic performance, environmental characteristics and economic efficiency. However, R290 is a flammable substance, thereby the promotion of R290 STHACs is hindered by its potential fire risk to the building resulting from leakage. At present, the most important measure to ensure the safety is to strictly limit the refrigerant charge by domestic and international standards, which will impact the R290 STHAC's heating performance. But in fact, when the leakage of R290 occur from a STHAC, the distribution of R290 in STHAC, and the leaking rate also will seriously affect the safety of the R290 STHAC. In this paper, a practical method of installing a solenoid valve near the capillary was presented, the refrigerant leaking rate in R290 STHAC was carried out through quasi-liquid nitrogen method (QLNM), and the R290 concentration in the room after leakage was also measured by detectors. Compared with the common STHAC, experimental results of leaking rate showed that after the installation of a solenoid valve, the R290 leaking rate and concentration in the room was obviously reduced, thereby the safety of the R290 STHACs was substantially improved.