Numerical and experimental investigation of the influence of generating pressure on the performance of a one-phase ejector installed within an R245fa refrigeration cycle

Abstract The highest compression ratio (Cr) of an ejector refrigeration system could guarantee the high efficiency for such systems. The present paper studied the impact of generating pressure on Cr for the ejector installed in an ERS. Signal processing techniques were applied to analyse the acquired signals of an R245fa ejector refrigeration system and revealed the existence of periodic noise in the experimental data. The Moving average filtering method eliminated the periodic noise from the signals and improved the experimental precision. Then, the influence of the generating pressure on the ejector’s performance was studied using the filtered experimental data, for different condenser temperatures ranging from 20 to 24 °C. It was observed that there is an optimum value of the generating pressure that simultaneously maximizes the ejector Cr and minimizes the suction pressure. The developed 1-D thermodynamic model of the ejector showed that the ejector operates in the subcritical mode when the generating pressure is below the Cr optimum point, while operates in critical mode at or above this optimum generating pressure.