Reducing the noise from the cavity by tuning the compressor’s oil level

Abstract

This paper proposes a unified solution for noise of two different versions of the same compressor. First, the problem was identified as a high noise in 1kHz third-octave band from the version using R134a refrigerant and 1.25kHz band from R600a version. The first hypothesis was the noise coming from the motor through shifting frequency, which would explain the different frequency ranges for different refrigerants. However, this was debunked experimentally, and results are shown in this paper. The other hypothesis was the noise coming from the cavity. This was proved to be the problem’s root cause and this paper shows the simulated and experimental results which corroborates the inference. Therefore, we propose a single solution for both versions by using an optimized amount of oil, to control the cavity volume.