Multi Ejector and pivoting-supported R744 application with AC for supermarkets

Abstract

CO2 refrigeration units are gaining market shares thanks to the ability to provide an energy efficient performance for industrial and commercial refrigeration applications in any climate. As with all the applications, the investment and operation costs should be kept as low as possible, to reduce the payback time and promote the introduction of innovative system solutions. In this work the flexibility achieved by implementing the pivoting technology in a supermarket refrigeration application is investigated both at design- and partial load conditions. The air conditioning (AC) load is also considered within a wide range of ambient temperatures. The Multi Ejector block utilized will be analyzed in terms of performance and its effect on the compressor combinations at different operating conditions. The objective is to increase the flexibility of the centralized rack through a proper design and sizing of the compressor pack equipped with the pivoting technology, while maintaining the efficiency and reducing the investment costs. This work shows that a Multi Ejector pivoting-supported system will be beneficial from the flexibility and capital costs point of view, and the benefit will be more consistent if the AC load is part of the integrated system architecture. Furthermore, a thorough investigation has been conducted whenever the ejector capacity is too high compared to the load, proposing two alternative solutions.