Comparison of Noise Calculation Methods of Air Conditioning Duct System used in China and USA

• DOI: 10.1016/j.proeng.2017.10.278
• Publication Date: 2017-11-01T04:31:59Z
• Authors: Yalin Liu; Yaocheng Dong; Lei Zhao
• Keywords: ASHRAE 90.1

A large number of potential noise sources appear in building HVAC&R systems installation. Noise generated central plant can be confined within installation rooms, located the basement or on top a building, and treated properly. But ductwork still remains as an effective sound transmission path inside which turbulent flow is source broadband noise. Air distribution system including fan, straight pipe, elbow, branch take-off, grilles, diffusers, terminal boxes, manifolds, etc. should designed carefully with acoustical calculation to minimize transmissions. However, methods for regeneration attenuation recommended by Practical HVAC Design Manual, China (2008) ( PDM ) [5] ASHRAE Handbook (2015) AAH [1] are not fully identical. Therefore, these two compared taken exemplify their differences. Airflow through attenuations components calculated terms methods, respectively. It found that method used mainly based empirical formulae, some figures tables. Few formulae given related chapters , but figure table based. Result indicates airflow elbow well take-off from almost identical, while values duct at low frequencies obviously different. The differences even reach 26dB 1.74dB case studied. We referred provided CIBSE Guide B4 (2016) [3] more closed measured values, cases very limited. Thus, lot research carried out this direction better method. And determine updated USA also gradually.