Performance study on compressed air refrigeration system based on single screw expander

• Taking single screw expander in refrigeration system has many advantages.
• Air refrigeration system with single screw expander shows good work performances.
• The adiabatic efficiency of 65% is achieved for single screw expander in experiment.
• A high COP can be obtained in high intake pressure and rotational speed.

A new kind of expanders, called as single screw expander, has been developed by our team and applied to refrigeration systems. The present paper is to determine experimentally the refrigeration performance of a compressed air refrigeration system which is based on a single screw expander with 175 mm diameter rotor. Results indicate that the single screw expander has good refrigeration performances with a 70 °C odd temperature drop and an adiabatic efficiency above 65%. A high refrigerating output can be obtained at high intake pressure and high rotational speed. The coefficient of performance (COP) varies a little with increasing intake pressure at low rotational speed, but has an obvious increase with increasing intake pressure at high rotational speed; and the higher the rotational speed, the higher the COP. The maximum COP of 0.9 can be achieved. This preliminary study shows that the compressed air refrigeration system based on single screw expanders exhibits good refrigeration performances.