Compact air plenum silencer
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Solution Overview
Problem
Conventional noise attenuation methods in HVAC systems, such as long line-of-sight silencers and elbow joints, are inefficient and space-constrained, failing to adequately reduce noise from HVAC components, particularly at return air ducts.
Innovation Solution
A compact air plenum silencer with internal baffles and perforations that redirect and attenuate sound waves, providing a 90-degree pathway for airflow and increasing sound attenuation time within a constrained space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional silencers are used to attenuate noise in return air ducts, then noise reduction is achieved, but the silencers require excessive space and are inefficient at reducing noise from HVAC components
Solution Approach 1:
The silencer is divided into multiple sections with baffles positioned at different locations within the housing. Each baffle segment reflects sound waves in a specific direction, creating multiple reflection paths that collectively attenuate noise across different frequency ranges while maintaining a compact overall structure.
Solution Approach 2:
The patent introduces a 90-degree directional change in the air flow path using baffles that redirect sound waves perpendicular to the original propagation direction. This dimensional change in the sound wave path increases the effective attenuation length within a compact volume by utilizing spatial redirection rather than simple linear extension.
2Object-affected harmful factors
If long line-of-sight silencers are used to attenuate resonant wavelengths, then noise reduction is achieved, but the device complexity and space requirements increase
Solution Approach 1:
Multiple functional elements (baffles, perforated surfaces, and housing structures) are merged into a single integrated silencer unit. The baffles serve dual purposes: they reflect sound waves to create attenuation paths while also serving as structural support elements within the housing, reducing overall device complexity.
Solution Approach 2:
The silencer housing and baffle elements incorporate curved and angled surfaces that redirect sound waves through smooth transitions rather than sharp edges. This curvature optimizes sound wave reflection patterns for attenuating resonant wavelengths while simplifying the manufacturing process compared to complex angular geometries.
3Object-affected harmful factors
If elbow joints are introduced in return air ducts to eliminate line-of-sight, then noise coupling is reduced, but the device complexity and space requirements increase
Solution Approach 1:
The silencer housing serves multiple functions simultaneously: it acts as a noise attenuation chamber, a directional flow redirector with 90-degree bends, and a structural mounting element for the baffles. This multi-functionality eliminates the need for separate elbow joints and reduces the overall space required compared to traditional duct modifications.
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 up to 27 dB across various frequency bands, optimizing noise attenuation in HVAC systems with limited space.
Implementation Method 1
the plurality of perforations are configured to allow airflow through the volume of the body
Implementation Method 2
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.