The noise and the vibration in a twin-screw refrigeration compressor unit are tested experimentally in order to improve the operation environment and the performance. By spectrum analysis

it was found that the higher noise and the larger vibration occurred when the unit was running at integer multiple of compressor baseband frequency

which indicated that the compressor was the main source of vibration and noise of the unit. Some noise and vibration reduction methods were also presented. The results of experimental comparison of the screw compressor unit before and after improvement indicate that improving the rotor profile design

adjusting the meshing clearance of female rotor and male rotor

and enhancing the rotor machining precision are significantly effective for noise and vibration reduction.