Performance simulation analysis of a novel dual-piston two-stage carbon dioxide linear compressor

In this study, an innovative two-stage linear CO2 compressor with dual piston is proposed and its simulation model is developed. The dynamic characteristics of the two-stage dual-piston compressor are comprehensively analyzed. The simulation results indicate that the dual-piston configuration leads to gas forces oscillating around the zero axis, resulting in a reduction in the mean gas force, allowing for the replacement of the resonance spring with gas springs and magnetic springs. The dynamic performance of the two-stage linear compressor is compared with that of a single-stage linear compressor. The moving center offset of the dual-piston two-stage compressor is reduced by approximately 90 %. The gas equivalent stiffness and the equivalent damping at the TDC (Top Dead Center) get lower than the single-stage one by 25.7 % and 11.6 % as the pressure ratio is set at 2.5. The leakage during the compression process gets lower by more than 20%. The dual-piston compressor demonstrates excellent capacity and modulation capabilities, with a theoretical increase in cooling capacity of over 300 W when the stroke is increased from 6 mm to 8 mm.