Carrefour Hypermarket in Nichelino: a step further also in refrigeration
In the complete new hypermarket, Carrefour Italy has chosen the top of technology, also for the refrigeration. The new hypermarket is based in Nichelino, a town close to Turin. Everything is brandnew: the facility, the store concept and also the building which is equipped with the most advanced systems. The refrigeration installation follows this criteria: a full CO2 system with parallel compression, heat recovery for tap water and facility heating, liquid and gas ejectors. Two booster racks provide 360 kW for medium temperature refrigeration and 72 kW for low temperature refrigeration supplying 7500 m2 sales area, with total 380 m of cabinets, 570 m2 of refrigerated rooms and laboratories.
Through the pressure difference between high pressure side and liquid receiver, the ejectors can convoy liquid and vapour CO2 on the receiver, without any additional energy.
Through liquid ejectors it is possible to overflow the evaporators: the CO2 on the liquid phase has a notable higher heat transfer capacity than the one in the gas phase. Consequently, based on the evaporator’s potential, the evaporation temperature will increase from – 6 °C to – 2 °C for MT utilities and from - 30 °C to - 26 °C for LT utilities. This leads to a further compressors’ work reduction, and, ultimately, an electrical energy consumption reduction.
Similar installations are working in Switzerland since more than a year and there are electrical savings about 25% in comparison to a traditional booster with parallel compression. Additionally, there is the heat recovery in order to heat up tap water and to cover a part of the facility heating requirements.
The ejectors
The gas and liquid ejectors, combined with the parallel compression, facilitate savings in energy consumption, because they are reducing the compressors’ work and the throttling losses on the high pressure valve.Through the pressure difference between high pressure side and liquid receiver, the ejectors can convoy liquid and vapour CO2 on the receiver, without any additional energy.
Through liquid ejectors it is possible to overflow the evaporators: the CO2 on the liquid phase has a notable higher heat transfer capacity than the one in the gas phase. Consequently, based on the evaporator’s potential, the evaporation temperature will increase from – 6 °C to – 2 °C for MT utilities and from - 30 °C to - 26 °C for LT utilities. This leads to a further compressors’ work reduction, and, ultimately, an electrical energy consumption reduction.
Similar installations are working in Switzerland since more than a year and there are electrical savings about 25% in comparison to a traditional booster with parallel compression. Additionally, there is the heat recovery in order to heat up tap water and to cover a part of the facility heating requirements.
Not only economical benefits
Everything leads to economical and energetic benefits. Not to forget is the huge benefit of the environment: on one hand the carbon footprint reduction by indirect emissions reduction, because of the advanced refrigeration and the reduced energy heating request, and, on the other hand, the direct emissions reduction because of the low CO2 GWP (the GWP of CO2 is 1, against the GWP of 3922 for the R404A and of 1430 for the R134a). Further with the CO2 technology there will be no impact by the F-Gas regulation that will affect all refrigeration installations. The installation will probably have a longer life and will have different management benefits to consider.
31.10.2016
