Noise source identification of the hermetic reciprocating compressor for refrigerator

Noise source identification of the hermetic reciprocating compressor for refrigerator has been investigated. Since the compressor shell housing is designed as airtight chamber to suppress refrigerant gas coming into contact with outside atmosphere, behaviors of the compression driving part are difficult to observe. So far, noise generation mechanism of the hermetic reciprocating compressor is studied by empirical estimation or intuitive consideration. Therefore, novel approach is required to figure out the relationship between compression process and noise generation. In this paper, behavioral features of primary components such as valve system and cylinder pressure are investigated by using the custom-designed compressor. Noise characteristics are clarified by measurement of another mass-produced compressor, separately. In order to identify the relation between compression procedure and noise generation simultaneously, synchronization of measured time signals is carried out. Short time Fourier transform (STFT) analysis is performed to verify noise generation mechanism with respect to both time and frequency domains. In addition, correlation between operating speed and noise characteristics is considered as the reciprocating compressor drives at various speed according to operating conditions of the refrigerator.