This dataset includes the data for two transcritical CO2 refrigeration systems installed in Italy and Portugal within the project MultiPACK. The real performance of the units providing refrigeration and space air condition is measured. the data was collected from two different sites/units:The unit in Central Italy The unit is based on a booster concept with parallel compression and expansion work recovery by means of ejectors for both vapour pre-compression and liquid recirculation. Semi-hermetic compressors are installed, three compressors for each suction pressure level. For each suction group, one out of the three compressors is inverter-driven to allow a smoother capacity modulation. The unit delivers the heating demand and the cooling loads of the supermarket by means of an Air Handling Unit AHU. The CO2 directly flows through the heating and cooling coils of the AHU.The unit in Portugal The MultiPACK system is based on a booster concept with parallel compression and expansion work recovery by ejectors for both vapour pre-compression and liquid recirculation.Semi-hermetic compressors are installed, three compressors for both MT and LT suction groups and four compressors for the Auxiliary compression suction group. For each suction group, one compressor is inverter-driven to allow a smoother capacity modulation. The unit also delivers the entire heating and cooling loads of the supermarket by means of two air handling units AHU.