Noise transmission from a small, hermetic, reciprocating compressor

In recent years, refrigerant compressor design has become increasingly focused on limiting noise emissions, as many of these units are installed in residential spaces. This paper aims to characterize the noise emitted from a small, hermetic, reciprocating compressor and identify the primary transmission path of noise from the compressor to its shell enclosure. Radiated sound power measurements show that the compressor projects noise that peaks at frequencies most sensitive to the human ear. Transmissibility measurements show that the compressor’s vibration isolation system becomes ineffective at high frequencies, as it is mounted to a non-rigid foundation. Measurements of transmissibility and radiated sound power of production line and rigidly-mounted units suggest that the mechanical transmission path dominates the shell excitation across the frequency spectrum. The paper concludes by proposing a general design modification to reduce the radiated noise from similar units.