Recent developments in advanced ejector technology

The objective of S. Elbel and N. Lawrence paper* is to present a review of developments in the use of ejectors for expansion work recovery in vapour-compression systems focusing on the past several years. Significant advances in the areas of multi-dimensional ejector modeling, alternate ejector cycles that may be more practical for real systems, ejector cycle control strategies, and commercialization of ejector systems in real applications have occurred. Future work should focus on alternate ejector cycles and uses of the ejector that help ejectors become better suited for real applications. Work can also continue on the development of accurate multi-dimensional ejector models that will aid in ejector design. The greatest opportunity for future work in the field of ejector technology seems to be on how to incorporate the ejector cycle into real systems. Practical issues such as compressor oil return and design of efficient, compact liquid-vapor separators (or development of systems that do not require separators) do not always receive sufficient attention in ejector studies. There is also very little research on how to design other system components for use in ejector systems. In particular, the design of the evaporator can have a very significant effect on the performance of an ejector cycle, especially for low-pressure refrigerants. Finally, the control of ejector cycles to achieve reasonable COP improvement over a range of operating conditions requires further investigation. These practical issues seem to have been addressed sufficiently for large-scale refrigeration systems, as indicated by recent successful installations of ejectors in CO2 supermarket systems, but the focus now may need to shift to simpler methods to address or avoid these issues in order to make ejectors suitable for smaller applications as well. Review of recent developments in advanced ejector technology. S. Elbel, N. Lawrence Direct link to this paper in Fridoc: http://goo.gl/PlaQF5