HISTORY

There are around 1 million supermarkets in Europe. The annual energy use in supermarkets in Germany is estimated to be 16 TWh, in Spain 6.8 TWh, in Italy 8.2 TWh, and in Norway about 1.5 TWh. The refrigeration system is normally responsible for 30 to 70 % of the electricity bill of a supermarket and heating, ventilation and air conditioning systems (HVAC) between 15 and 25 %. The average annual specific energy consumption5 of commercial buildings in India is 210 kWh/m2, owing to the energy demanding Refrigeration & Heating, Ventilation and AC (R&HVAC) equipment. The value for supermarkets is up to 3 times higher. The necessary heat pumping installations, maintaining food safety and comfort inside the buildings, require a large amount of primary energy and additionally cause relatively large direct greenhouse gas (GHG) emissions due to leakage of the applied refrigerants (HCFCs and HFCs). 

The refrigeration systems operated in southern Europe do have similar efficiency challenges due to high ambient temperatures during the summer. INDEE-N proposes the further development and integration of innovative concepts initiated by SINTEF; i.e. CO2 ejectors which utilize the expansion work to significantly improve the system energy efficiency, and novel thermal storage devices. The use of such concepts together with complete energy solutions has a potential to save up to 25 % of the total energy consumption of a supermarket.

The concepts of integrated CO2 vapor compression systems (refrigeration of foodstuff & cold stores, AC and heat pumping) is relatively new (2010 onwards) and only a few examples of successful application of such systems exists5. The idea of applying multiple ejectors, designed for the CO2 vapor compression systems to improve the energy efficiency and performance at high ambient temperatures can be applied in both Europe as well as in Asia for numerous application areas. A complementary consortium and new knowledge that could invoke technological development and lower the investment costs of the ejector supported CO2 vapor compression units is required.