As the HVAC industry transitions toward low-GWP refrigerants, R-744 (CO₂) heat pumps are attracting growing interest across commercial and industrial applications. The transcritical operating behaviour of R-744 presents control challenges that differ fundamentally from conventional refrigerant systems, and realising the full efficiency potential of these systems requires a coordinated approach spanning the refrigerant circuit, ejector operation, and water-side hydraulics.
This presentation focuses on COP optimisation as a practical control objective, examining how gas cooler pressure setpoints, ejector expansion, and water-side variables interact to define the system operating point. Drawing on applied case studies from commissioned installations, the presentation explores how optima ...