Fresh products and perfectly refrigerated foodstuffs – In the Rimi hypermarket in Klaipėda, Lithuania, nothing is left to chance thanks to a CO2 hypermarket system which serves as a booster system. The hypermarket belongs to Rimi Baltic, one of the leading retailers in the Baltic States consisting of over 230 stores (supermarkets, hypermarkets, “supernettos”, distribution centers etc.).
Supermarket uses rack with three transcritical and two subcritical GEA CO2 compressors
In the year 2014, ROLVIKA installed the CO2 booster system in the hypermarket in Klaipėda, the third biggest city of Lithuania. ROLVIKA is providing refrigeration, trading and food preparation equipment solutions as well as technical services for retailers and industries in Lithuania, Latvia, Byelorussia and other countries.
The refrigeration system of the Lithuanian hypermarket consists of 48 cabinets and cold-rooms with medium temperature and 9 cabinets and cold-rooms with low temperature in the hypermarket area. The capacity is 120 kW with evaporation temperature of -10°C (medium temperature) and 11 kW with -35°C (low temperature) evaporation temperature.
GEA CO2 compressors ensure optimal refrigeration of all foods in the hypermarket. The refrigeration system compressor rack is equipped with five semi-hermetic GEA compressors specially designed for CO2 systems. Three transcritical HGX34 CO2 T compressors are used for medium temperature cooling and two subcritical HGX12e CO2 compressors handle the low temperature cooling.
The system works with the natural refrigerant R744 (CO2) which presents a very low Global Warming Potential (GWP) of value 1, and can therefore be seen as a climate neutral refrigerant.
Lead compressors for each partition are equipped with a frequency inverter. This option will optimize the system operation points and the impact on energy consumptions for the refrigeration system. The rack is controlled by “pRack” Carel controllers.
A “Guntner” high pressure gas cooler with stainless steel tubes is used for cooling the CO2 gas. The unit is equipped with fans that meet the efficiency requirements of the Energy-related Product (ERP) Directive 2009/125 /EC.
The system works according to the heat recovery principle, so that the energy received from the refrigeration cabinets and rooms can be used efficiently – e.g. as heating or to supply hot water to the hypermarket. This option will reduce the amount of gas or energy used for heating as well as the operating costs in the hypermarket.
All users have a separate control board with automatic controller, probes and pressure transmitters. All controllers are connected to a monitoring system which helps to coordinate operation points or to get alarm of faults.
The application installed by ROLVIKA has been used since May 2014. This is the second, but not the last CO2 hypermarket installation, implemented by the company in 2014. The rack builder was the Italian company SCM Frigo Italy.
Supermarket Refrigeration with GEA CO2 Compressors
Regarding applications with CO2 in low and medium temperature refrigeration, so-called Booster systems are used. High pressure of low temperature compressor is discharged directly to the suction side of the second compressor stage. Different plant constructions of these Booster applications are used for example in supermarket applications. Transcritical and subcritical GEA CO2 compressors are used.