Analysis of energy consumption by applying a new generation of CO2 compressors.

A new generation of energy-efficient compressors for the natural refrigerant CO2, called ECOLINE+, offers maximum efficiency for the lowest carbon footprint possible. Line start permanent magnet motors (LSPM) are applied with this compressor range and show the core of the improvement. This motor technology is a hybrid solution that contains a stator and a squirrel-cage rotor with additional permanent magnets, combining the robust design and the line starting behavior of the asynchronous motor with the higher efficiency of a synchronous motor. Due to the synchronous speed of the motor, no voltage is induced and as a consequence, no current flows through the rotor. This effect reduces rotor aluminum losses and therewith increases the motor efficiency. Due to lower electrical losses and synchronous speed, the mass flow rate is intensified as well. Based on the EN13215:2016 and the applied rating points, the work shows the potential to reduce the energy consumption and increase the seasonal efficiency performance ratio (SEPR). The analytical study breaks down in detail the influences on the motor and compressor efficiency.