Ejector characterization for refrigeration applications with natural refrigerants

Employing natural fluids in refrigerating plants at warm climate conditions sometimes impacts negatively on the system performance. Ejectors can play a key role in configurations aiming at improving the efficiency of such systems, however their geometry has to be optimized in order to gain the best benefit. Scope of this work is a numerical investigation on the geometry of the ejector in a cascade plant configuration with natural refrigerants, aiming at identifying the influence of various geometry aspects on the performance of the system. A one-dimensional model is employed for the ejector, while the performance of the refrigerating plant is evaluated in different operating conditions in order to seek the optimal configuration.