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

The environmental impact of supermarkets is significant not only because of the indirect effect from CO2 emissions at the power stations but also due to the direct effect arising from refrigerant leakage to the atmosphere. One approach through which the overall energy efficiency can be increased and the environmental impacts reduced, is through 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. This paper reports on experimental and theoretical investigations of such a system and its potential application in a supermarket. The results show that the system can offer energy savings of 30%, greenhouse gas emission savings of 43% and a payback period of just over 3 years compared to conventional systems.

► Integration of CO2 refrigeration and trigeneration systems in supermarkets.
► Experimental test results on a subcritical volatile-DX CO2 refrigeration system.
► Average overall COP of CO2 refrigeration system of 5.8.
► Energy and GHG emission savings of 30% and 43% respectively.
► Payback period was found to be 3.2 years.