The UNES/U2 supermarket chain (a subsidiary of the FINIPER Group) based in Italy is very enthusiastic about innovative systems and has a robust environmental and energy policy. The changes began in 2009 with the establishment of the first integrated system called eCold, which was capable of managing low- and medium-temperature refrigeration, as well as the air conditioning in the U2 supermarket in Magnago.
Since then, the system developed and offered by TDF, the consultants, who specialise in energy management for commercial refrigeration, has continued to evolve in order to optimise costs and meet the needs of its client; UNES. Twenty-three supermarkets are now fitted with this type of installation. This latest innovative solution works in a cascade system and combines Solstice® ze fluid with CO2 for the U2 supermarket in Parma. Now a single system can meet all the requirements for cooling, heating and air conditioning within the same supermarket.
For Dr Gianfranco Iannace, Technical Director at Unes /U2 :
« It is essential to establish systems that are not complex, do not require large amounts of energy and are smaller in size while limiting costs, anticipating forthcoming legislation and optimising the installation to its maximum. So-called transcritical systems are costly, complex and can be dangerous. Depending on the layout of the shop, whether it has an outdoor space or not, we can adapt while maintaining the spirit of our philosophy ».
The Magenta U2 Supermarket tests R-448A
With a surface area of 1,200 m², the new supermarket located in an existing shopping centre had a revamp. To limit the investment costs, Natale Mandelli from TDF, in collaboration with the installation engineer from Frozen, decided to put a “NG System” installation in place using the reduced space in the existing machine room and the two roof top units for the air conditioning section.
Solstice® N40 (R-448A) was chosen, a fluid developed by Honeywell and distributed by Climalife and Progetto Freddo after comparing it to R-404A/R-407F. R-448A provides good cooling output at low temperatures with compressors the same size as R-404A and avoids putting liquid injection in place for an evaporation temperature of -35°C. Theoretical comparisons were completed by TDF using software from the compressor manufacturer Frascold who approved the use of R-448A. Its GWP of 1387 is an additional benefit as it is the refrigerant with the lowest environmental impact on the market to replace R-404A and helps to address forthcoming F-Gas bans.
« For the Magenta supermarket, N40 works very well from -35°C to + 50°C and meets all three requirements: low- and medium temperature, air conditioning in summer and heating in winter together with total heat recovery. It also offers the advantage of having a single type of refrigerant in the van for maintenance » stressed refrigeration technician, Andréa Simoni
This solution allows cost savings on energy use thanks to a food condensing unit that uses an integrated system with total heat recovery. A dedicated condensation and electronically-controlled partitioning system sends the heat dissipated to the air treatment unit located in the roof which then heats the premises, meaning that a boiler is no longer needed.
« The lack of a boiler is a plus, this allows us to lighten constraints relating to fire protection and reduce the investment and running costs,” recalled Gianfranco Inannace.
In summer, the computerised “control and regulation system” optimises the operating mode of cooling units allowing cooling and dehumidification of the air entering the premises at the point of sale.
In this way, the multi-functional condensing unit can be used simultaneously to serve the installation for the refrigerated food cabinets and low- to medium-temperature cold rooms, the heating installation, the production of domestic hot water and the air conditioning installation. A remote management system allows all the parameters to be monitored from a distance and thus reduce running costs while improving energy efficiency. Management of the “inverter” system to partition and optimise the operation of the compressors along with use of the electronic ventilators on the air condensers prolongs the life of the installation, reduces energy consumption and the acoustic impact.
All partners are satisfied with the simplicity of using Solstice® N40 and the result obtained. The experience will soon be adapted for the opening of a new store in Cassano where the unit will be found inside the shop.
In summary: The advantages of the integrated NG system
- A single thermal unit, no boiler, no air conditioning system (chiller/VRV)
- Reduction of 25 to 30% in total energy consumption
- Overall reduction in CO2 emissions
- Reduction of 15 to 20% in the electricity power installed
- Reduction in running and maintenance costs
- Limited noise emissions as the ventilators run at minimal speed at night
Characteristics of the “NG system” thermal system at Magenta U2 supermarket
- Cooling capacity temp Chill : 51.55 kW (-10 / + 45°C – External temp. +35°C)Cooling capacity temp. Freezing: 26.4 kW (-35 / + 45°C – External temp. 35°C)
- Heating capacity: 147 kW (Desired ambient temp. + 20°C – Circulated air + 33°C – Condensation +40°C -. External temp -7°C.)
- Cooling capacity (A/C) in summer: 129 kW (Sales area +25°C – Air entering sales area +18°C – Evaporation +5°C – Condensation +45 °C – External temp. +35°C)
- Refrigerant: R-448A – 250 Kg
- Frascold -10/+45 compressors: S15.52 – (MT) – Number of compressors: 2
- Frascold +5/+45 compressors: V25.71 – (AC) – Number of compressors: 2
- Frascold -35/+45 compressors: S15.56 – (BT) – Number of compressors: 3
- Absorbed electricity consumption total of compressors: 81 kW.
- Estimate of the annual consumption of the integrated NG system (MT – LT – A/C – Heating): 400,000 kW/year
- Estimate of the annual consumption for 4 standard systems (MT – LT – A/C – Heating): 580,000 kW/year