Degree Name

Master of Engineering (Hons.)


Department of Mechanical Engineering


The effective use of energy is an important issue for society considering the future increasing energy demand, restricted use of fossil fuels and associated environmental problems.

This thesis is concerned with an ejector refrigeration system as an energy conservation technology. An ejector is the main component and replaces the compressor in the refrigeration cycle. A "constant area analysis method" is employed to analyse and design an ejector and several computer simulation programs are developed for that purpose. The following are examined in detail by simulation and experiment: the parameters which affect the ejector performance, the "choking" condition of the ejector which governs the ejector operation and the system performance.

The findings of this study are summarised as follows:

(1) The developed simulation programs are a useful tool for prediction of the critical condition for ejector choking as well as the ejector and system performance.

(2) Experimental results were considerably below the performance predicted by the computer program though trends were as expected. Further work would be required to improve the system performance.

(3) The ejector performance is affected greatly by choking.

(4) In further work, it would be desirable to examine nozzle design and friction effects in the ejector mixing tube in more detail for accurate analysis/design.