The experimental study of R290 mass distribution and indoor leakage of 2 HP and 3 HP split type household air conditioner

R290 is a promising future refrigerant, but its flammability presents the biggest obstacle to its adoption. This paper is concerned with the safety of a 2 HP and 3 HP split type household air conditioner (STHAC) with a 400 g, 450 g and 500 g charge of R290. Evaluation of the mass distribution of R290 in the indoor and outdoor units of the 2 HP and 3 HP STHAC was carried out and the R290 concentration distribution in a sealed room after a leakage under different scenarios was also examined. The results show that most of the refrigerant (72-80%) was located in the outdoor unit during the steady cooling mode. In the event of a leak indoors the combustible zone only appears underneath the leak position in the sealed room. The range and residence time of the combustible zone will increase with higher refrigerant charge quantity and negligible fire hazard appeared in the room if the leakage hole was 0.5 mm. In addition, the practical and achievable approach to significantly reduce the leaking rate and minimise the flammability hazard was found to be by installing a solenoid valve behind the capillary tube and is effective in both 2 HP and 3 HP STHAC. (C) 2019 Elsevier Ltd and IIR. All rights reserved.