Experimental studies on the transcritical CO2 two-phase ejector refrigeration cycle were carried out

and the effects of the working conditions and the geometric parameters of the ejector on the performance of the system were analyzed. The experiment results indicate that the COP and cooling capacity of the system increase with the rise of the cooling pressure

while decrease with the increase in the outlet temperature of the gas cooler. For the systems using different throat diameter of the nozzles

the COP of the system using the larger throat diameter of the nozzle is larger than that using the smaller one under the same condition. For systems using different diameter mixing chambers of the ejector

with the increase in the cooling pressure

the COP of the system using the smaller diameter of the mixing chamber varies greatly

and is lower than that of the system using the larger one under the lower cooling pressure condition. While under higher cooling pressure condition

the performance of system using smaller diameter of the mixing chamber is better. The COP of the transcritical CO2 refrigeration cycle with a two-phase ejector is increased by 14% comparing to the traditional cycle at the same condition.