Preliminary Design of the Two-Phase Ejector under Constant Area Mixing Assumption for 5 kW Experimental System

¹ Dokuz Eylül University, Faculty of Engineering, Mechanical Engineering Department, Tınaztepe Yerleşkesi 35397 Buca, İzmir, Turkey
² Ege University, Solar Energy Institute, 35100 Bornova, İzmir, Turkey

^* Corresponding author: ugurcan.atmaca@deu.edu.tr

Abstract

Ejector expansion refrigeration cycle is the modification of the vapour compression refrigeration cycle with the implementation of a two-phase ejector and a vapour-liquid separator to improve the cycle performance. In this study, main geometrical parameters of an ejector, i.e. diameters of the motive nozzle throat, motive nozzle outlet, suction nozzle outlet, and constant area mixing section are calculated in order to provide the preliminary design aspects at various operation conditions. The thermodynamic model of the ejector is established with reference to constant-area mixing assumption. The equations are solved in Matlab^®. The environmentally-friendly refrigerants, R1234yf and R1234ze(E) from the hydrofluoroolefins (HFOs) and R134a which is about to be phased out by the F-gas Regulation are used in the analyses. When compared to the previous literature findings, the current research aims to compare the dimensions of a two-phase ejector to be used in an experimental system having 5 kW cooling capacity for these three refrigerants.