Integration of CO2 refrigeration and trigeneration systems for energy savings in supermarkets

A small number of trigeneration systems have been applied in recent years in the USA, UK and other countries, but the difficulty with such systems is the relatively low COP of sorption refrigeration systems particularly when they operate at refrigeration temperatures.
It has been shown through experimental investigations in the laboratory and simulation studies that trigeneration technology based on a micro gas turbine integrated with an ammonia water absorption refrigeration system can provide promising economic and environmental benefits in supermarket applications.

An article* written by I. Suamir, S.A. Tassou and D. Marriott published in the International Journal of Refrigeration reports on experimental and theoretical investigations regarding the integration of CO2 refrigeration and trigeneration systems where the refrigeration generated by the trigeneration system is used to condense the CO2 refrigerant in a cascade arrangement.
Results from modelling of conventional and integrated CO2 refrigeration and trigeneration energy systems in a supermarket have shown the latter system to provide fuel energy savings of the order of 30% and CO2 emission savings of 43% over the conventional system.
The payback period of the system was found to be 3.2 years.
The proposed system can be used with both volatile/DX and all CO2 transcritical cascade systems. In the event of trigeneration system failure, the CO2 refrigeration system can be arranged to operate transcritically.

I. Suamir*, S.A. Tassou, D. Marriott, Integration of CO2 refrigeration and trigeneration systems for energy and GHG emission savings in supermarkets. IJR vol. 35, issue 12.
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