Based on the incomplete superheating cycle of a refrigeration system (from suction superheat of the compressor to two-phase compression)

the characteristics of the change in the performance of a refrigeration system

such as the coefficient of performance (COP)

refrigeration capacity

pressure ratio

compressor power consumption

electric efficiency

and exhaust temperature

are investigated by running the rolling rotor compressor in different low-frequency conditions. An optimal control strategy is then put forward. The results show that if the compressor operating frequency is properly reduced and the quality of refrigerant is controlled at 0.98 ≤ x < 1 for a short time

the cooling capacity would be increased by 8.3% to 16.6% compared to the conventional superheat control conditions (5–10 K)

and the COP would increase by 12.5%–15%. In addition

the electrical efficiency of the compressor was only 0.3%–0.7% lower than that of the conventional superheat control condition

and the electrical efficiency at the lowest frequency (25 Hz) in the experiment was the largest. At the lowest frequency in the experiment

the energy-saving effect was significant

and the pressure ratio was further reduced. The temperature of the exhaust gas was greatly reduced by 40.3% when x<0.90.