Resulting design criteria

Detailed information on this topic would go beyond the scope of this publication. In any case, the system and control techniques differ substantially from conventional plants. Already when considering pressure levels as well as volume and mass flow ratios specially developed components, controls, and safety devices as well as suitably dimensioned pipework must be provided.

The compressor technology is particularly demanding. The special requirements result in a completely independent approach, e.g. considering design, materials (bursting resistance), displacement, crank gear, working valves, lubrication system, as well as compressor and motor cooling. The high thermal load severely limits the application for single-stage compression. Low temperature cooling requires 2-stage operation, whereby separate high and low pressure compressors are particularly advantageous with parallel compounded systems.

The criteria mentioned above in connection with subcritical systems apply to an even higher degree to lubricants. Further information: Lubricants for compressors.

Further development is necessary in various areas, and transcritical CO₂ technology cannot in general be regarded as state-of-the-art yet.