Operating Characteristics of Twin-Screw Refrigeration Compressor with Different Refrigerants Based on the Semi-Empirical Model

The refrigeration industry is advancing towards environmentally friendly, efficient, and safe alternative refrigerants. To analyze compressor performance with various refrigerants, this study proposes a modified semi-empirical model with 13 characteristic parameters. Experiments were conducted with R22, R507, and R744 under variable operating conditions to identify parameters and validate the model. The experimental and simulated results showed strong agreement, with average relative errors of 2.07% for input power and 1.17% for mass flow rate. Using a typical operating condition, the losses and efficiencies of different refrigerants were compared at various frequencies. Results indicate that R744, with the lowest pressure, leakage, and power losses, demonstrated superior performance. While R507 and R22 showed similar efficiencies, the efficiency of R507 declined significantly at frequencies above 50 Hz due to increased pressure losses. This study provides a theoretical basis for optimizing compressor designs for various refrigerants.