Monitoring of a CO2 commercial refrigeration system serving a supermarket in Southern Europe

In the present paper, a CO2 commercial refrigeration unit serving a 1500 m supermarket located in Southern Europe is presented. The unit consists of a booster compressor rack with parallel compression, with ten compressors arranged to provide around 20 kW cooling capacity at low temperature and 90 kW cooling capacity at medium temperature. The system, in addition to the cooling load, provides all the thermal functions in one unit: it integrates a heat exchanger for the air conditioning (130 kW) and two stages heat recovery, for sanitary hot water production (20 kW) and for space heating (100 kW). The refrigeration unit is fully equipped with pressure and temperature sensors, flow meters, power consumption and capacities analysers. The monitoring data are useful to understand how the considered system operates under different boundary conditions across a year. The focus of this paper is on the performance of the system during the winter period when some heat is recovered from the cycle for space heating purposes.