Technical solutions used:

CO2 rotary compressor with Carel DC Inverter speed controller

Carel electronic expansion valves (HP and Flashgas) required to manage the transcritical CO2 cycle (in particular, they control the pressure in the liquid tanks and therefore the liquid outlet temperature)

Condensing unit with EC motor fan (variable speed), 2 liquid tanks mounted in parallel, liquid line incorporating filter drier and liquid sight glass, CO2 charging valves, and HP safety pressure switch

Carel controller and supervisor controlling the refrigeration unit to ensure that the compressor always remains within its application envelope

Evaporators with electronic expansion valves and control boxes that communicate with the chiller controller to optimize oil return, running times, and system efficiency

Educational activities:

Commissioning & configuration (settings, expansion valve, etc.)

Addressing and network configuration between refrigeration unit and refrigeration stations

Preventive and corrective electrical and refrigeration maintenance

Study of CO2 (R744) refrigeration circuits and electrical circuits

Enthalpy diagram, energy balance and calculation of performance coefficients

Forecasting of transcritical cycle operating conditions

Key points:

CO2, a response to the "natural fluids" trend that has emerged since the implementation of the F-gas schedule on the phasing out of high GWP (Global Warming Potential) fluids

CO2 is now the preferred solution in supermarkets and convenience stores

Stable product temperature thanks to the power modulation device and floating LP management

Condensing unit designed to meet the requirements of DESP Directive category 1, with maximum pressures of 120 bar (HP side) and 80 bar (LP side). CO2 condensing unit, electronic expansion valves, evaporators and piping with a maximum working pressure (MWP) greater than 80 bar, which has the advantage, in the event of a failure (compressor shutdown), of a rapid recovery. evaporators and piping with a maximum working pressure (MWP) greater than 80 bar, which has the advantage, in the event of a failure (compressor shutdown) synonymous with rapid pressure rise, of not requiring an "emergency device" such as a pressure maintenance unit

References:

CQ10: "Transcritical CO2" bi-split commercial positive refrigeration (MBP) (with evaporators in 0°C cold rooms – cooling capacity 2548W (-10°C/+32°C)

CQ15: CQ15: Transcritical CO2 mono-split commercial positive refrigeration (with evaporator in 0°C cold room – cooling capacity 2548W (-10°C/+32°C)

CQ25: CQ25: Transcritical CO2 mono-split for commercial negative refrigeration (with evaporator in -20°C cold room – Refrigeration capacity 3168W (-30°C/+32°C)

CQ09: Carel "MiniBoss" touchscreen supervisor option with communication capabilities

CQ00: Refrigeration technician's tools for installing and maintaining CO2 systems

CQ01: Workbench on casters equipped with 3 lockable storage compartments

PC22: 4-channel thermometer with PC display and acquisition (comes with 8 thermocouple probes and PC acquisition software)

Videos:

Start-up after a long shutdown of the installation:

R744 fluid storage in CO2 unit - Long shutdown of the installation:

R744 degassing:

Vacuum extraction:

R744 charge: