An Experimental Study for Reduction of Refrigerant Flow Induced Noise in a Passenger Vehicle

Air conditioning these days has become an indispensable part of human comfort due to rising global temperatures. In order to achieve thermal comfort in confined environments like residences, car passenger cabins, offices, etc., air conditioners are used. As the air conditioning units employ dynamic processes to maintain thermal comfort it creates many unwanted noises which lower the acoustic comfort. One of these unwanted noises is the refrigerant flow induced noise inside passenger cabin of an automobile when the air conditioning is switched on in a thermally soaked vehicle.

This paper elaborates about the study conducted on a HVAC system mounted on a calorimetric bench in a semi-anechoic chamber to understand the noise signatures and acoustic characteristics of refrigerant induced noise. This research investigates potential causes and solutions for noise generated by refrigerant flow. Additionally, using a typical NVH study setup, it assesses several mitigation strategies that have been investigated to eliminate or reduce noise caused by refrigerant flow. This study also tries to categorize and evaluate the decline in sound quality caused by the noise that is continuously generated by refrigerant-flow inside a car's passenger compartment.