Occupant comfort is the goal of all HVAC designers. Sound (or noise) is a key parameter in measuring comfort, in addition to temperature, humidity and Indoor Air Quality (IAQ). While acoustics consultants are usually involved in critical applications (such as performing arts centers), the task of creating a comfortable acoustic environment in most other applications falls on the HVAC engineer.
This is because most background sound sources are generated by the HVAC equipment The purpose of this manual is to familiarize the designer will the basics of acoustics, and to apply these basics to typical HVAC designs.
Using This Manual The manual can be used as an application guide or as a primer for using the McQuay Acoustic Analyzer™ software program.
The equations and approach described herein were used in the creation of the Acoustic Analyzer program.
Small differences can exist between the software and the manual because the Acoustic Analyzer program uses equations to estimate values as opposed to the tables listed in the manual. However, the difference in values will be very small. Examples that show how to perform some analyses are included in double lined boxes. Helpful tips are also provided.
Table of Contents
Introduction
Using This Manual
Sound Basics
General
Wavelength and Frequency
Decibels
Sound Pressure vs. Sound Power
Octave Bands
Human Response to Sound
Sound Pressure Evaluation Criteria
Acceptable Sound Levels
Sound Testing Methods
HVAC Equipment Acoustics
Calculating Sound Pressure from Sound Power
Outdoor Sound Analysis
General
Outdoor Sound Analysis Basics
Open Field Analysis
Sound Barriers
Reflecting Walls
Indoor Sound Analysis – Zoned Comfort Systems
General
Sound in a Room
Room Constant and Sound Absorption Coefficient
Thompson and Schultz Equations
Indoor Sound Analysis – Ducted Zoned Comfort Systems
Radiated and Discharge Sound Power
Multiple Path Concept
Duct Sound Path
Converting Ducted Sound Power to Sound Pressure
Duct Breakout Sound Path
Return Air Sound Path
Diffuser Sound Path
Radiated Sound Path
Evaluating All the Sound Paths
Indoor Sound Analysis – Central Systems
General
Multiple Paths
Central System Duct Sound Path
Transmitted Sound
Main Duct Breakout
Return Air Path
Evaluating Multiple Sound Paths and Locations
Regenerated Noise
General
Evaluating Regenerated Noise
Conclusions
Appendix 1 - References
Appendix 2 – HVAC Equipment Sound Measurement Stds
General
Appendix 3 – Various Acoustic Properties of Materials
General
Please Download Here
0 komentar:
Post a Comment