Multi ejector and the impact of ejector design on the operation of a CO2 refrigeration system

An ejector with a certain design will have the best performance within a certain area of the operational envelope. Maximizing the benefit of the ejector can be achieved in two ways; by varying either the design of the ejector; or change the operational conditions to a point within the desired operation envelope of the available ejector design. If the design does not suit the current operation point, the ejector will have different characteristics and reduced efficiency. Different system designs will have different requirements and will require/benefit most from ejector designs that are adapted to the unique characteristics of each system type. The present paper is briefly describing an investigation of the impact of the design parameters on the functionality of the ejector, the capacity control and the system performance. An emphasis was given on the variation of the motive nozzle of an ejector with fixed geometry. Experimental studies were conducted by SINTEF with a multi ejector. A steady state model was utilized to study the system implications.