R744 (CO2)  Theory

In house or on your site

1 Day

Background to the use of natural refrigerants

• Summary of long-term alternative refrigerants and their current applications (HCs, HFOs, R717, R744).
• Key characteristics and advantages of R744.

Critical point and triple point

• Explanation of critical point and triple point using the phase diagram and pressure enthalpy diagram.

R744 hazards

• Asphyxiation. Pressure.
• Trapped liquid.
• Dry ice.
• Freeze burns.
• Cylinders

Working Safely with R744

• Personal protective equipment.
• R744 fixed leak detectors and alarms.
• Connection / charging equipment.
• How to prevent dry ice formation.
• Safe cylinder handling, storage and transport.
• Risk assessments – explanation and worked example.

R744 cascade systems

• Outline of basic cascade system.
• Component differences, including pipe work, compressors, cascade heat exchangers, expansion valves, evaporators, pressure relief valves.

R744 as a pumped secondary refrigerant

• Outline of basic pumped secondary system.

Trans critical systems & Trans critical booster systems

• Outline of typical trans critical system for HT applications.
• Component differences.
• Explanation of requirement for two stage compression on LT R744 applications.

Reducing leak potential and improving resilience

• Potential leak points, including pressure relief valves venting.
• Types of joint – brazed joints to be used.
• Pressure testing for leak tightness.
• Leak test regime.

Installation and commissioning & Service of R744 systems

• Pipe working and insulation.
• Pressure testing for strength and leak tightness.
• Evacuation.
• Charging.
• Leak testing methods.
• Venting