Noise Reduction Scheme for Air-Cooled Heat Pump Unit

PurposeThe air-cooled heat pump unit is widely used in the central air-conditioning system in large buildings such as shopping malls and hospitals. However, the noise emitted from the air-cooled heat pump units affects the life and work of the surrounding residents seriously. Therefore, it is of great importance to reduce the noise emission of the air-cooled heat pump units.MethodIn this study, the noise characteristics of a heat pump unit (type: YSPA0405HE) were measured. It was found that the sound pressure level reached 68 dB at the residential buildings and most noise energy concentrated in the 250-1000 Hz frequency band. To reduce the noise emission, we designed a semi-enclosed acoustic enclosure to isolate noise, in which labyrinth-style inlet and outlet channels were adopt to reduce noise spreading and ensure adequate air intake.ResultsThe noise level at the residential buildings was measured with and without installation of the acoustic enclosure. Results shown that more than 10 dB noise reduction is achieved at the residential buildings, which reached the national standard for the noise level of the second-class acoustic environment area.ConclusionThis study provides a reference engineering example for the noise reduction of related heat pump units.