Comparison of single and parallel ejector operation in transcritical R744 cycle.

Abstract

Ejector systems have been a field of research for many years. One of the latest topics are transcritical cycles with R744 refrigerant. The main reason of installing ejectors in that type of systems is the recovering of the pressure energy, lost in the classic cycles during the throttling processes.The thesis consists basically of two parts, which both of consider the topic of parallel ejector operation. In the third part conclusions are presented.The first part is a simplified feasibility study for a concept R744 cycle with three different ejector geometries working in parallel. MS Excel spreadsheet was created for general parameters calculations and for specific motive nozzles mass flow estimations.The second part contains results of measurement procedures on the SINTEF test facility. First, single ejector operation was examined. Basing on the test results, characteristic of P2GGC ejector geometry has been created. Later on, a new module with two different geometries (P2GGC and A2CDC) working in parallel has been built on the rig. The parallel ejector operation has been examined, as well as single operation of each geometry. The results has been compared, considering the influence of each operation on the system parameters.In the third part final conclusions are presented. Some ideas of further work are mentioned as well.