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Control of a Transcritical Cycle for Optimum Efficiency
Published May 18, 2003 by Institution of Mechanical Engineers in United Kingdom
The application of carbon dioxide as refrigerant in automotive air conditioning systems is under serious consideration. A key element in the efficient operation of a CO2 system is the need for a more sophisticated control system than is required by current R134a systems. This arises because of the transcritical nature of the process for most operating conditions. It is found that for any operating condition there exists a head pressure at which the efficiency of the system is a maximum. The challenge is to control the system at the requisite head pressure.