Full scale supermarket laboratory R744 ejector supported & AC integrated parallel compression unit.

There are more than 1 million supermarkets in Europe. The annual energy consumption in supermarkets can be up to 5% of the national electricity. The cooling system is responsible for 30 to 70% of the electricity bill in a store and the heating, ventilation and AC system (HVAC) for 15 and 25%. Supermarket chains prefer to apply R744 as working fluid for centralized commercial refrigeration systems whenever possible. However, today's R744 systems are not optimized regarding energy efficiency, i.e. no
expansion work is utilized. The use and integration of ejectors can reduce energy consumption by up to 20% compared to parallel compression units at high ambient temperatures, which are currently the 'top runner' units. To increase the knowledge related to design and control issues of ejector supported commercial refrigeration units a new laboratory facility is built at SINTEF/NTNU within the SuperSmart-Rack project funded by the Research Council of Norway and industrial partners. The installed capacities of the equipment are adapted to represent a standard Norwegian Supermarket, including some real display cabinets. Additional cabinets are simulated with tube in tube heat exchangers. The paper will give an overview of the system layout, applied components and the operation envelope.