Low-Noise HVAC Airflow Design

Vehicle air conditioning system that reduces airflow noise while keeping compact size. The system has a narrow inlet section that widens downstream to prevent backflow and noise. A flow path width adjusting unit connects the inlet to the housing wall. It decreases width upstream of the narrow nose section. This matches the inlet width profile to gradually widen the airflow path. This prevents backflow and reduces noise compared to a sudden width change at the narrow nose.

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Automated bioprocess control system using Raman spectroscopy to monitor and optimize cell culture processes like bioreactors without invasive sampling. The system has a Raman spectrometer to continuously monitor cell culture parameters like glucose, lactate, ammonia concentrations inside the bioreactor. A controller uses the Raman data to autonomously adjust nutrient feed rates and other process parameters to maintain optimal conditions for cell growth and product quality.

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Centrifugal fan with improved airflow and reduced noise compared to traditional designs. The fan has multiple air inlets instead of just one. The main air inlet is at the top, but there are also secondary air inlets at the bottom. The impeller has a larger projection at the top than the main air inlet. This overlaps the secondary air inlets. This allows more airflow through the secondary inlets while preventing excessive noise from the larger main inlet. The secondary inlets have irregular shapes. The housing also has a shield to block some of the impeller edges. This further reduces noise. The fan housing, impeller, and support structure are configured to balance airflow, pressure, and noise.

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Air conditioner that reduces noise and odor during drying mode by sequentially turning off fans after cooling instead of running them at high speed. The air conditioner has multiple fans to blow air through the heat exchanger and outlets. After cooling, all fans turn on for drying, then they are sequentially turned off. This prevents loud noise and mold release when fans stop. Sensors monitor indoor temp, heat exchanger temp, and humidity to determine when drying is complete.

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A blower assembly for vehicle HVAC systems with improved airflow and noise reduction. The blower assembly has a blower wheel inside a scroll housing with annular scroll channels defined by inner and outer ring walls. The blower wheel has blades and ribs in the inlet channel between the inner and outer ring walls. This configuration draws air axially into the scroll channels and discharges it radially. The inner ring wall between the channel walls reduces airflow leakage. The scroll channels also help quiet the blower.

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Compact air plenum silencer for HVAC systems that reduces noise levels from return air ducts without requiring long silencers or elbows. The silencer is installed in the return air inlet and has multiple baffles inside with perforated volumes. The baffles are fixed to the housing and have perforations that allow airflow but also redirect sound waves. The baffles are positioned on opposite sides of the housing to provide noise attenuation in both directions.

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Centrifugal fan designs that reduce noise and improve airflow in confined spaces like laptops. The fan housing has features like angled cutwaters, slotted cutwaters, and acoustic dampening materials to mitigate tonal and broadband noise. These fan housing concepts were tested and showed significant noise reduction and flow improvement compared to standard fans. The designs involve modifications like angled cutwaters that extend at acute angles from the fan base, slotted cutwaters, and acoustic dampening materials in the housing.

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A low noise vehicle fan assembly for air distribution in cabins like aircraft that uses toroidal shaped fan blades instead of conventional airfoil blades. The toroidal shape forms loops that reduce noise compared to traditional fan blades. The loops create a low pressure zone behind the blade tips that captures airflow, reducing turbulence and noise. The fan assembly also encloses the motor and impeller in a case around the toroidal blades to further reduce noise transmission.

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Outdoor unit for refrigeration systems that reduces air resistance while rigidly supporting the fan motor to suppress noise. The unit has a motor support plate with a reinforced area around the fan motor insertion hole. The reinforced area is created by bent plates that extend from the inside edge of the hole. These bent plates reinforce the plate around the fan motor without increasing its front-rear projection. This provides sufficient rigidity to support the fan motor without narrowing the airflow passages.

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Air diffuser for a transport refrigeration unit evaporator that improves airflow efficiency and reduces noise compared to conventional designs. The diffuser has a unique shape with angled walls and turning vanes that gradually increase in depth as the airflow turns. It also has guide vanes and a finger guard at the outlet to prevent fingers from entering. The diffuser is molded as a single piece and can accommodate multiple fans. This customized airflow path reduces velocity, aerodynamic losses, and impingement.

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A blower device for a heating, ventilation and air conditioning (HVAC) system in a vehicle that improves airflow and reduces noise. The blower has an uneven number of blades and vanes to create a swirling airflow pattern. The blower housing has an inlet with a preswirler of unevenly shaped vanes that slope toward the blower wheel. This uneven configuration causes the air to swirl as it enters the blower, which reduces turbulence and noise compared to a symmetrical swirler. The blower blades themselves can also be unevenly spaced.

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A lubrication system for a pump drive that prevents direct contact between the motor and housing to improve operation and lifespan. The system uses a lubricant reservoir, conduit, and sensor. The reservoir stores lubricant, the conduit directs lubricant into the motor housing, and the sensor monitors the reservoir level. If the level drops below a threshold, motor operation is reduced to avoid dry running. This prevents motor-housing contact by keeping the motor submerged in lubricant.

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Centrifugal blower design with reduced surge and clogging issues. The blower has an impeller and a scroll casing. The scroll casing has a tongue to guide the gas flow and a peripheral wall with a first and second planar portions. The clearance between the wall and impeller is smallest at the second portion. This configuration prevents gas stagnation and turbulence at the narrowest part of the passage, reducing surge and noise. The blower also has more blades (60 or more) to increase low flow static pressure.

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This work is devoted to the design and evaluation of a low-noise outlet guide vane (OGV) aiming reduce rotorstator interaction noise using leading-edge serrations tested on ECL5 ultrahigh-bypass-ratio model in PHARE-2 rig at Ecole Centrale Lyon. First, radially varying 2D proposed evaluated by means fast analytical prediction tool strip approach. Then, an iterative process combining 3D Reynolds-averaged NavierStokes (RANS) calculations with in-house modeler carried out achieve suitable geometry while minimizing aerodynamic penalties. Following this process, high-fidelity simulations based lattice Boltzmann solver are performed assess sound power level reduction achieved serrated OGV (by comparison untreated baseline case primarily tested). Due low-compressibility assumptions present method, limited reachable higher regime (45% nominal rotational speed). Hence, available numerical predictions compared experimental data terms both acoustic performances. A rather good agreement obtained reductions up 3 dB from broadband intake radiation 6 bypass duct considered operating points. I... Read More

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Ventilation fan with blades that change shape along their length and have a capping plate covering the blade ends near the fan inlet. The blades have chords that taper inward or outward towards the inlet, rather than maintaining a uniform width. This allows for better airflow and reduced noise compared to conventional fans with uniform blades. The capping plate prevents debris from entering the fan housing through the blade ends. The blades also have a secured portion attached to the hub and a free portion extending outward. This provides flexibility in blade design without compromising structural integrity.

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An arrangement to reduce noise at the air inlet of a blower ventilator like a respirator without using foam or other soft materials. The arrangement has a connecting element with an inlet and outlet, and at least one labyrinth element with parallel channels. The labyrinth element fills at least 40% of its volume with channels that guide air and deflect noise. The connecting element and labyrinth elements are configured so air flows in parallel axes with a 90 degree deflection between the elements. This routing reduces noise by reflecting and deflecting the operating noise.

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Compact sound device that mitigates noise near airflow openings like duct endpoints using acoustic resonance. The device surrounds the opening and has a cavity with a partition. The cavity reflects sound waves at target frequencies to mitigate noise. This compact design saves space compared to devices inside ducts and avoids aerodynamic disruption. The cavity lengthened by the partition enhances resonance.

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Efficient attenuation of low-frequency sound (<1000 Hz) while maintaining unrestricted airflow remains a long-standing pursuit in noise control engineering. Here, ventilation barrier is integrated with Helmholtz resonator and an open channel. A density-based topology optimization approach employed to distribute material within the resonant cavity, effectively reducing at target frequencies. For frequencies 550 Hz, 500 450 400 350 optimized designs achieve transmission losses exceeding 25 dB. Multiple solutions for same show minimal variation performance. Sound pressure particle velocity distributions are analyzed reveal insulation mechanisms units. Acoustic experiments validate designs, results agreement numerical calculations. Furthermore, 48.1% channel area maintained, ensuring efficient airflow. Ventilation tests confirm effective air circulation, demonstrating advantages over conventional barriers expanding potential applications diverse scenarios.

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Axial fan assembly for heating, ventilation, and air conditioning (HVAC) systems that can be used in air handling units while using less energy and generating lower noise compared to traditional blowers. The assembly includes an axial fan, inlet ring, stator, outlet ring, and fan deck. The components are arranged to direct air through the assembly, straighten the flow, and prevent turbulence. This improves fan efficiency and reduces noise. The assembly can be used in HVAC units to circulate air while consuming less energy than traditional blowers.

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Centrifugal fan design that improves efficiency and reduces noise compared to conventional fans. The fan blades have outlet edges shaped to create progressively larger gaps between them. This gradual expansion of air channels reduces velocity and mitigates expansion losses. The fan housing has transition portions on the sidewalls that extend radially outward. These transitions lead to openings between the end walls that gradually increase in size. This gradual expansion reduces velocity and pressure drop at the fan outlet. The fan motor assembly further compresses the size by integrating the motor into the fan wheel, reducing overall length.

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Composite material for acoustic applications like air ducts and hushpanels that provides high acoustic performance, light weight, and ease of assembly. The composite has layers of fibrous materials like nonwovens sandwiched between layers of nonwovens. This layering creates a multi-acoustic impedance mismatch profile that amplifies noise reduction compared to standalone layers. Overmolding onto specific areas allows attaching features without filling the entire composite. The composite can be thermoformed into complex shapes. The fibrous layers have controlled porosity for air permeability and sound absorption. The layering enables customization of acoustic properties while maintaining light weight and assembly benefits.

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Centrifugal air fan with reduced noise and improved efficiency. The fan impeller has blades with decreasing thickness towards the outer circumference. This gradual vane taper reduces rapid pressure fluctuations and increases airflow volume compared to uniform thickness blades. When air flows back into the impeller from the bell mouth, it collides with the inner blades at lower speeds, preventing noise and flow separation.

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Guiding mechanism for range hood centrifugal fans that improves airflow efficiency and reduces noise. The mechanism guides the airflow as it exits the fan's volute to make a turn before discharge. This reduces energy loss and aerodynamic noise compared to abrupt turns. The mechanism is a curved shape with a smooth internal flow path at the fan's rear outlet. This allows the airflow to smoothly transition and turn without turbulence.

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Reducing airflow noise in a centrifugal compressor with a casing treatment that involves a specific arrangement of spoke and wing-like features in the compressor housing. The spoke portions connect the inner wall of the air intake hole to an annular portion inside the hole. The wing-like features extend from a tubular portion upstream of the annular portion. The spoke and wing features are arranged at matching positions around the annular portion. This forms sub-flow paths that branch off the main flow path, join back together, and engage with the annular portion. Equalizing the spoke and wing positions prevents flow separation and irregularities that can cause noise.

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A centrifugal blower with reduced noise and simplified manufacturing. The blower integrates the blades, shroud, and impeller cup into a single component. This allows a unique impeller cup shape that enables a zero-degree slope angle between the shroud and impeller. This eliminates undercut regions that can generate noise from flow separation. The integrated component simplifies molding compared to separately molding the parts. The impeller cup fits onto the main plate after molding.

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Blower fan design to reduce noise by preventing separation of airflow from the blades. The fan has blades with serrations along the leading edge from the center to the tip. This reduces separation of airflow from the negative pressure side of the blade. Additionally, the blade shapes direct the airflow towards the separation limiting structures of adjacent blades on the rear side. This further reduces airflow separation at the blade base.

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Air amplifier for fan assemblies like bladeless heaters/coolers to improve airflow, efficiency and noise reduction. The amplifier has an inlet to connect to the fan, an airflow cavity with walls, and a lip at the front wall edge. This lip partially obstructs airflow from the exhaust outlet. This focuses and amplifies the airflow by creating a higher pressure in the cavity compared to the fan exit. It enables improved airflow, efficiency and noise reduction in a low pressure system.

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A noise-reducing and nonuniform tip clearance structure for centrifugal compressors that reduces aerodynamic noise compared to traditional uniform tip clearance. The impeller tip clearance gradually decreases from the leading edge to the trailing edge, with a higher rate of decrease near the leading edge. This reduces radial backflow and cross-blade flow along the clearance that can increase flow loss and noise. The nonuniform clearance distribution also reversely compensates for impeller deformation under load.

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Compact, high efficiency residential HVAC air handler with close coupling of components for improved performance and noise reduction. The air handler has a mixed-flow fan, a wide-angle diffuser, and two high resistance media (like filters and heat exchangers) placed immediately upstream and downstream of the fan and diffuser. The media are positioned close to the fan and diffuser blades/vanes, within specific distances to leverage synergy between the components. The close coupling improves efficiency and reduces noise compared to conventional HVAC designs with standalone components.

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<div class="section abstract"><div class="htmlview paragraph">This paper presents a fully parallelized Computational Acoustics (CA) module, integrated within the Simerics-MP+ platform, developed for prediction of noise source power and far-field propagation across range Fluid Dynamics (CFD) applications. Utilizing Ffowcs Williams-Hawkings (FWH) acoustic analogy, CA module seamlessly integrates with existing CFD workflows, offering minimal computational overhead less than 5% increase in runtime. Extensive validation has been conducted against analytical, numerical, experimental data various scenarios, including monopole dipole emissions, flow around slender bodies, circular cylinders aero-propellers. These studies underscore reliability framework accurately identifying sources assessing impact design modifications, significantly reducing need expensive physical prototyping industries such as automotive aerospace.</div><div paragraph">Building upon these foundational capabilities, study extends application to challenging task simulation axial fans, commonly empl... Read More

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<div class="section abstract"><div class="htmlview paragraph">This study evaluates the effectiveness of two hybrid computational aeroacoustic methodsLighthill wave model and perturbed convective modelin simulating HVAC duct noise in automotive industry. Using component-level acoustic testing a Ford duct, simulations were conducted at varying airflow rates to assess accuracy both models predicting noise. The Lighthill model, suitable for analysis regions outside turbulent flow areas, showed good correlation with experimental data, especially frequency range 100 Hz5000 Hz, but sometimes struggled pseudo-noise effects low frequencies near regions. which is anywhere domain, underpredicted sound pressure levels as well. Both high-frequency (>5 kHz) due insufficient mesh time-step sizes. Despite these limitations, provided better overall agreement results. also identified resonance peak 160 captured offering valuable insights further optimization. These findings underscore potential improve design quieter systems, enhancing vehicle comfort customer satisfaction.... Read More

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Blower design with a diffuser to convert the direction of airflow discharged by the fan into ascending airflow. This allows the blower to efficiently move air vertically without needing a separate upward fan or ducting. The diffuser extends vertically from the fan outlet and guides the air upward. It reduces noise and flow separation compared to conventional rising airflow generators. The diffuser shape and angles are optimized to balance noise reduction and efficiency.

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Cabinet air conditioner design that reduces noise by buffering the airflow out of the heat exchanger before it enters the ducts. The air conditioner has a shell with an air inlet in the rear and an air outlet in the front. The airflow path is split into two sections. The heat exchanger is between the cross-flow fan and rear shell. The air outlet of the heat exchanger is not opposite the air inlet of the through-flow duct. This causes the air to turn or shift as it leaves the heat exchanger before entering the ducts. This buffering reduces the peak air speeds and noise at the outlet.

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A codesigned shroud for a chassis with components and fans that balances airflow for cooling and attenuates acoustic energy to protect sensitive components like hard drives from fan noise. The shroud has channels aligned with the airflow directions, with baffles in a noise attenuation channel perpendicular to the flow. The baffles have absorbent material to block direct acoustic paths. This balances cooling airflow while preventing noise from fan vibrations and flow turbulence.

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A fan and air conditioner design with improved airflow and reduced noise compared to conventional designs. The fan has a two-section volute tongue that steps in height. The first section extends along the air duct opening and the second section extends from the end of the first section. This smooths the airflow transition and reduces vortex formation compared to a single tongue. The air conditioner has a matching stepped volute tongue in the duct cover and seat. This joint configuration improves airflow in the duct and reduces noise compared to conventional ducts.

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Air passage silencer with improved low frequency attenuation and reduced wind noise compared to conventional expansion type silencers. The silencer has a tapered opening structure at the expansion to outlet connection, surrounded by a rear space. A porous material is added in the rear space opening to absorb sound. This provides resonance in the tapered space for low frequency attenuation, without backflow turbulence. The tapered opening reduces wind noise compared to a sudden expansion. The expansion size, tapered shape, and rear space dimensions are optimized for performance.

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Heating, ventilation, and air conditioning (HVAC) terminal unit with improved airflow distribution and noise reduction compared to traditional units. The terminal unit has a sound attenuator positioned opposite the air inlets that directs return airflow into the unit. This balances the airflow distribution to the blowers and reduces noise compared to uneven airflow. The attenuator has an inlet facing the return air inlet and outlet into the unit. Baffles inside the unit further direct the airflow. This balanced airflow reduces blower speeds, pressure losses, and noise compared to uneven flow.

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Air conditioner design with reduced noise by preventing vortex formation in the air ducts. The ducts are split using a dividing piece near the impeller inlet. This divides the airflow entering the impeller into two streams, one from each duct half. The stream entering from the second duct half passes through an angle formed by the duct shape, preventing vortex formation. This prevents pressure pulsations and noise caused by vortex interaction in the ducts.

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Fresh air module for air conditioners that reduces noise compared to conventional modules. The module has a housing with an inlet and outlet, a fan assembly with a motor and wind wheel, and a partition between the motor and fresh air duct. The motor is outside the duct in a separate compartment. This isolates the motor noise from the airflow, preventing amplification and reducing overall noise.

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Air outlet panel for floor type indoor air conditioners that improves airflow efficiency and reduces noise compared to conventional designs. The panel has a strip-shaped plate with a grid section for high airflow and a weaker air outlet section. Sealing strips around these sections weaken flow to adjacent areas, directing more air through the intended outlet. This prevents unnecessary flow losses and noise. The sealing strips also have fillers and brushes to further regulate airflow. The panel can switch between the grid and weaker outlet sections for different applications.

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Air port device and air conditioning unit with reduced noise. The air port device has a silencing cover inside the air duct between the inlet and outlet. The cover has holes for airflow and disperses it to reduce turbulence. It also has a cone to guide air uniformly. This reduces noise by scattering and refracting sound, lowering flow velocity, and absorbing noise with cotton.

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Air duct design for air conditioners that reduces vortex wind phenomenon, noise, and improves user experience compared to conventional spiral case air ducts. The duct has detachable volute covers and seats that form extendable tongues to gradually expand airflow from the inner duct to the outer duct. This reduces vortices and noise compared to sudden expansion in conventional ducts. The outer tongue extends further than the inner tongue and the outer duct opening is smaller. The tongues' lengths and angles are balanced to further reduce noise.

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Device to reduce noise from air conditioning ducts at the air outlet. The device has features to address the two main sources of noise: contact friction between the air and duct walls, and friction between the air and dust. It uses an air guide mechanism with smaller diameter tubes that the air flows through before reaching the main duct. This reduces contact friction noise. The device also has sound-absorbing panels and angled air guide plates to intercept dust particles, concentrating friction noise there instead of the duct walls. The panels have ventilation holes to allow smooth airflow. By breaking up the duct into smaller ventilation areas with staggered features, noise reduction is improved.

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Fan fairing, fan assembly, and air duct system to improve noise reduction of cooling fans. The fan fairing has an extension direction and is made of a cover body with arc-shaped curved sections connected in sequence. The sections bend in opposite directions. This rectifier shape guides airflow passing through the fairing. The opposite bending directions prevent eddy currents and turbulence compared to same-direction bends. The fairing can be used on fans, air ducts, and equipment to reduce fan noise.

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An air conditioning ventilation duct with good noise reduction for HVAC systems. The duct has an auxiliary pipe with a fan, filter plates, spiral duct, and noise-reducing deflector to capture and disperse airborne particles. The deflector and fan reduce noise by scattering and slowing airflow. The duct also has exhaust ducts with sound-absorbing cotton boards. The duct attaches to the main duct and has an outlet with a silencer plate.

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A multifunctional air pipe for reducing noise and wind resistance in applications like ductwork, that uses a golf ball-inspired design. The pipe has features like an adjustable scraping strip, conical air guides, a collecting box, a sprayer, and an interception system. These components inside the pipe clean impurities, stabilize flow, and capture debris to reduce noise and wind resistance compared to conventional ducts. The golf ball-shaped rear cones of the conical air guides further disturb the flow for noise reduction.

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Muffling noise in ducts using resonating membranes without openings to prevent wind noise. The membranes are integrated into the duct walls and vibrate in response to sound. They form closed resonant spaces that suppress duct end noise when excited by nearby sources. The membranes are designed to have higher order vibration modes for better absorption. The membrane positions are optimized for interference cancellation. This allows muffling specific frequencies without amplifying others. It avoids the drawbacks of open resonators like Helmholtz resonators that generate wind noise.

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Outdoor unit for an air conditioner that reduces noise generated by air entering the unit. The unit has fins on the heat exchanger, a vent in the casing wall facing the fins, and an air inlet. The vent allows straight airflow between the fins while the inlet has higher resistance. This prevents air from entering gaps between the fins and casing, reducing turbulence and vortices that could cause noise. The vent interrupts any inlet airflow in that direction.

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Reducing noise in air flow devices like compressors by using resonators in the flow ducts. The method involves forming holes in the duct wall, covering them with tensioned acoustically resistive screens that are fluid-contacted with the duct air and cavity gas. This creates noise-suppressing resonators that attenuate sound in specific frequency bands. The acoustic properties of the screens are optimized based on the duct geometry to maximize noise reduction.

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Reducing noise of a ceiling air conditioner by improving the internal airflow path. The ceiling air conditioner has a unique configuration that reduces noise compared to conventional centrifugal air conditioners. The improvements include: 1. A heat exchanger with a water pan below it to collect condensate. This prevents water dripping from the heat exchanger and reduces noise from dripping. 2. A through-flow wind wheel that generates negative pressure in the airflow path. This prevents dead angles and vortex formation in the airflow passage, which can cause noise. 3. A wind shielding part around the wind wheel that covers the airflow entry and exit points. This prevents air leakage and improves airflow efficiency. By combining these features, the ceiling air conditioner reduces noise compared to conventional centrifugal air conditioners. The water collection, airflow path improvements, and wind wheel en

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