A soundproof structure body includes a first tube structure and a second tube structure connected to the first tube structure and having a cross-sectional area different from the first tube structure, in which a structure body having a cross-sectional area smaller than a cross-sectional area of the first tube structure is installed in the first tube structure, and a transmission loss in a case where the structure body is installed in the first tube structure with respect to a case where the structure body is not installed in the first tube structure is positive at two frequencies adjacent to each other and difficult to generate an air column resonance mode in the first tube structure. This soundproof structure body generates a soundproof effect even at frequencies other than air column resonance of a tube structure such as a duct or a muffler, has a small size, and can obtain a high transmission loss in a wide-band.

A noise suppression apparatus for an air handling unit includes an inlet section connectable to a fan of the air handling unit. The inlet section includes a forward wall spaced apart from an aft wall to define an internal chamber, and an inlet wall extending between the forward wall and the aft wall, the inlet wall defining an inlet air opening. A plurality of internal walls in the inlet wall define a plurality of resonator openings that each open to at least one of a plurality of resonator sections within the internal chamber. The plurality of resonator sections include at least one quarter wave tube section and at least one Helmholtz resonator section. One or more resonator sections are configured to attenuate noise generated by the fan at two or more frequencies. At least one resonator opening of the plurality of resonator openings opens to a plurality of resonator sections.

Embodiments of the present technology are directed to air treatment reactor modules, and associated systems and devices. An exemplary reactor module can include a housing, an ultraviolet (UV) light source disposed within the housing, and a plurality of hollow elongate conduits disposed within the housing and peripheral to the UV light source. The UV light source and individual conduits can extend in a lateral direction perpendicular to the direction of air flow through the reactor module. The conduits can include a plurality of holes and be at least partially coated with a photocatalytic material. The housing can have an inner surface comprising a reflective material that, in operation, reflects UV light emitted from the UV light source.

Provided acoustic devices include an external housing defining an expansion chamber and a wall extending through and partitioning the expansion chamber into a central chamber and a peripheral chamber adjacent the central chamber, wherein an inlet and outlet communicate with the central chamber, and wherein the wall includes a plurality of apertures formed therethrough to allow air movement to and from the central and expansion chambers, the plurality of apertures sized to provide an average flow resistance ranging from 100 MKS Rayls to 5000 MKS Rayls. The acoustic devices advantageously show significant sound attenuation while streamlining air flow to reduce pressure drop across the expansion chamber.

Provided is a muffler for an air-conditioning apparatus, which is compact and has a small pressure loss, and an air-conditioning apparatus including the same. The muffler for an air-conditioning apparatus including a muffler main body which has small diameter portions on an inlet side and an outlet side, the small diameter portions having inner diameters smaller than an inner diameter of a central portion of the muffler main body, an inlet pipe connected to the small diameter portion on the inlet side of the muffler main body; and an outlet pipe connected to the small diameter portion on the outlet side of the muffler main body. The inlet pipe is inserted into the muffler main body, and has a distal end positioned at a center of a length from an inlet to an outlet of the muffler main body. The distal end side of the inlet pipe inserted into the muffler main body has an inner diameter smaller than an inner diameter of the inlet pipe on an upstream of the distal end side.

A sound suppression apparatus for installation inside a gas transport duct is provided. The sound suppression apparatus comprises a resistive sound-absorbing element (110) and a housing providing a reactive sound-attenuating element (130) communicating with a surrounding of the apparatus via opening in an outer surface of the housing. An outer surface of the sound suppression apparatus comprises an outer surface of the resistive sound-absorbing element and the outer surface of the housing. A gas transport duct comprising the sound suppression apparatus is also provided.

An acoustic metamaterial noise control system of embodiments of the disclosed technology combines acoustic metamaterial principles with absorptive materials, with a result of a significant reduction in sound radiation within, or emanating from, an HVAC duct. Sound waves that impinge on the noise control system placed at the end (terminal opening of an air duct to ambient space within a room/building), or at a predetermined place on the duct, cause the sound waves to reflect back to the start of the noise control system and also to be absorbed by sound waves within the absorptive core. This is accomplished by way of the use of micro-perforated panels (MPPs) placed in periodic manner with absorptive layers and air gaps to achieve anisotropic conditions to reflect and absorb sound waves for optimum sound reduction.

Embodiments of the present disclosure provide a diffusion muffling device, a diffusion resonance muffling device, a full-frequency diffusion muffling device, a muffling system for a ventilation channel, and a muffling method using the same, which include a plurality of diffusion muffling units disposed in the ventilation extension direction of the ventilation channel, wherein the plurality of diffusion muffling units are arranged in parallel in a direction with a predetermined angle between the direction and the ventilation extension direction of the ventilation channel, and a muffling passage is formed between each two adjacent diffusion muffling units, wherein each of the diffusion muffling units includes at least one diffuser, and each diffuser includes a plurality of convex portions so that sound waves entering the muffling passage are reflected multiple times in the muffling passage by the plurality of convex portions and then sound is attenuated. In the present disclosure, the diffusers are disposed to diffuse and reflect sound waves, so that the sound is attenuated in a long and narrow passage by multiple times of reflections of the sound waves, thereby improving the low-frequency sound muffling performance in the ventilation channel so as to effectively achieve an effect of sound muffling and noise reduction in ventilation.

A soundproofing device; the soundproofing device includes a body and a set of soundproofing sections disposed therein. In some embodiments, a soundproofing system is also disclosed herein and includes a set of soundproofing devices. The soundproofing device and the soundproofing system are useful for easy installation into ductwork of a building to provide substantial soundproofing to the same.

A sound suppression chamber for a heating, ventilation and air conditioning (HVAC) air handling assembly including a first end, a second end, and a middle portion. The first end includes an aperture that resonates with airflow from the HVAC air handling assembly, the airflow from the HVAC air handling assembly generating an incident sound wave corresponding to a target tone. The second end is closed and opposite the first end. The middle portion extends between the first end and the second end. The first end, the second end, and the middle portion defining a cavity of the sound suppression chamber. The sound suppression chamber generates a reflected wave that is 180 degrees out of phase from the incident sound wave and reflected into the HVAC air handling assembly through the aperture to suppress the target tone.