The air conditioning design process includes decisions to use outdoor air-cooled refrigeration chillers or indoor chiller with outdoor cooling tower. Many aircooled chillers utilize screw or rotary helical compressors, which emit very tonal noise and vibration in the outdoor environment. Complaints arise from residential properties in the vicinity, even though investigations show conformance with building code, ordinance or regulation permitted sound levels. Sound quality, in terms of tonality, unbalanced spectrum and on/off cycles, appears to increase perception and annoyance. Simple conformance to a noise ordinance may not be adequate to prevent neighborhood disturbances and complaints.
This paper presents acoustical issues that should be considered in site selection and orientation, equipment selection and details of air-cooled chiller installations. Environmental noise criteria are presented along with case studies that include on-site noise spectrum measurement results. Acoustical characteristics and site parameters are explored with respect to overall spectrum and level, relative contributions of compressors and condenser fans, other equipment noise radiation issues, sound paths to sensitive receivers, noise build-up between large structures, distances from source to receiver and effects of reflectors and barriers. Noise mitigation solutions are presented with photos, illustrations and discussions of several installations and the resulting improvements and performance limitations determined in the case studies.
Citation: ASHRAE Trans., vol. 118, pt. 2, San Antonio, TX
Product Details
- Published:
- 2012
- Number of Pages:
- 8
- File Size:
- 1 file , 1.8 MB
- Product Code(s):
- D-SA-12-C007
