Compact Air Plenum Silencer with Baffles for HVAC Noise Attenuation
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Solution Overview
Problem
Existing HVAC systems face challenges in reducing noise levels, particularly at the return air inlet, due to the limitations of conventional silencers and elbow joints in effectively attenuating noise within constrained spaces.
Innovation Solution
A compact air plenum silencer is introduced, which includes a housing with baffles that redirect sound waves and provide a 90-degree pathway for airflow and noise coupling, thereby increasing attenuation time and achieving high sound reduction within a compact volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional silencers are used in the return air duct, then noise attenuation is achieved, but the device occupies excessive space
Solution Approach 1:
The silencer is divided into multiple sections with baffles positioned at different locations within the housing. Each baffle segment handles specific sound frequencies and directions, allowing effective noise attenuation across a broader spectrum while maintaining a compact overall structure that fits within the return air duct space.
Solution Approach 2:
The patent introduces a 90-degree pathway that redirects airflow and sound waves in a perpendicular direction rather than using a long linear path. This dimensional change allows the silencer to achieve effective noise attenuation in a compact volume by utilizing spatial redirection instead of extended length.
2Object-affected harmful factors
If elbow joints are used to reduce noise coupling, then noise reduction is achieved, but the attenuation time is insufficient
Solution Approach 1:
Multiple baffles are positioned at different locations and angles within the housing to create multiple reflection paths for sound waves. This segmentation of the acoustic path increases the total attenuation time by ensuring sound waves undergo multiple reflections and interactions with different baffle surfaces before exiting the silencer.
Solution Approach 2:
The baffles act as intermediary elements between the noise sources in the air handler and the return air duct. These intermediaries redirect and attenuate sound waves through multiple reflections, extending the attenuation process and reducing noise coupling more effectively than a simple elbow joint.
3Productivity
If straight line-of-sight return duct conduit is used, then airflow efficiency is maintained, but noise transmission is exacerbated
Solution Approach 1:
The silencer housing with internal baffles serves as an intermediary device installed within the straight line-of-sight return duct. This intermediary structure maintains the direct airflow path for efficiency while simultaneously providing multiple sound reflection surfaces that attenuate noise transmission, resolving the conflict between airflow efficiency and noise reduction.
Solution Approach 2:
The straight return duct maintains its overall direct path for airflow efficiency, but local quality is modified by introducing the silencer housing with baffles at specific locations. These local modifications create sound reflection zones without significantly obstructing the main airflow path, allowing both airflow efficiency and noise reduction to coexist.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The compact air plenum silencer effectively reduces noise levels by providing a high degree of sound attenuation, making it suitable for applications with limited space, and outperforming traditional elbow joints in noise reduction.
Implementation Method 1
a plurality of baffles positioned within said housing, each baffle including a body defining a volume and has a plurality of perforations, wherein each baffle is affixed to the housing and wherein the plurality of perforations are configured to allow airflow through the volume of the body and redirecting sound waves
Data Source
AI summary
An apparatus for reducing sound levels in an HVAC system, the apparatus including a housing configured to be positioned within an air inlet vent for an HVAC system. The housing includes a first opening configured to intake air and a second opening configured to out put air and a plurality of baffles positioned within said housing, each baffle including a body defining a volume and has a plurality of perforations, wherein each baffle is affixed to the housing and wherein the plurality of perforations are configured to allow airflow through the volume of the body and redirecting sound waves.