Source identification and noise reduction of a reciprocating compressor : A case history

A noise source can be very complex in nature. In noise control engineering an essential first step is to identify the strongest contributing noise sources. This paper discusses a practical case history, in which a series of measurement techniques was applied to a reciprocating compressor to identify the strongest sound source. In addition numerical prediction methods were used to give direction towards a lower noise design of the compressor. Structural modifications to the compressor are discussed, leading to a significant reduction of the noise levels. The sound power level of the reciprocating compressor was reduced by 5 dB. Moreover, from a perceptual point of view, customers experience the sound as more robust and more pleasant as well, probably because of shifting frequencies.