A first ventilation duct line has a first portion having a first sectional area, a second portion having a second sectional area larger than the first sectional area, and a third portion having an inclined inner face connecting the first portion and the second portion to each other. Further, there is a second ventilation duct line having an opening portion positioned on an inner side of the first portion of the first ventilation duct line.

A reference microphone for detecting noise is located under a first duct. The noise is in the form of a first plane wave in the first duct. A speaker is located on a top of the first duct. Connected to an upper part of the first duct is a second duct including an error microphone. The first plane wave in the first duct passes through an acoustic path and reaches the second duct. The error microphone detects the sound, and the speaker outputs a second plane wave with an opposite phase for canceling the first plane wave.

A reference microphone for detecting noise is located under a first duct. The noise is in the form of a first plane wave in the first duct. A speaker is located on a top of the first duct. Connected to an upper part of the first duct is a second duct including an error microphone. The first plane wave in the first duct passes through an acoustic path and reaches the second duct. The error microphone detects the sound, and the speaker outputs a second plane wave with an opposite phase for canceling the first plane wave.

A sealing assembly includes a fixation member and a sealing member connected to the fixation member. The fixation member is configured to be connected to a casing of a window air conditioner that is to be supported at a window and has an accommodation groove. The sealing member is configured to be sealingly arranged between a window sash of the window and an inner wall of the window. The window sash is at least partially extended in the accommodation groove.

A silencer module for an air handling unit includes a first baffle and a second baffle spaced apart from the first baffle to form an air channel between the first baffle and the second baffle. The air channel is configured to receive a fluid flow and direct the fluid flow through the silencer module. The silencer module also includes a reactive acoustic feature formed in the first baffle. The reactive acoustic feature includes an attenuation profile configured to reduce propagation of tonal acoustic waves through the air channel.

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.

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 vertical humidifier with a stepped evaporator includes a housing. An evaporative water trough is provided inside the housing, and the stepped evaporator is provided in the evaporative water trough. A fan is mounted under the stepped evaporator, and an air inlet end of the fan is communicated with an air inlet of the housing. A water tank is further mounted at the upper portion of the evaporative water trough, the stepped evaporator is mounted around the lower portion of the water tank, and the water tank is further communicated with the evaporative water trough through a water inlet. An air outlet is provided at the upper portion of the housing, and the air outlet is communicated with an air outlet end of the fan. The stepped evaporator is arranged in an airflow channel between the air outlet and the air outlet end of the fan.

A vertical humidifier with a stepped evaporator includes a housing. An evaporative water trough is provided inside the housing, and the stepped evaporator is provided in the evaporative water trough. A fan is mounted under the stepped evaporator, and an air inlet end of the fan is communicated with an air inlet of the housing. A water tank is further mounted at the upper portion of the evaporative water trough, the stepped evaporator is mounted around the lower portion of the water tank, and the water tank is further communicated with the evaporative water trough through a water inlet. An air outlet is provided at the upper portion of the housing, and the air outlet is communicated with an air outlet end of the fan. The stepped evaporator is arranged in an airflow channel between the air outlet and the air outlet end of the fan.

An air conditioner unit includes a cabinet including a base pan that defines at least one alignment feature and a compressor mounted to the base pan using mechanical fasteners that pass through mounting feet and into mounting bosses defined on the base pan. A damper is positioned between the compressor and the base pan and includes a lower pad seated on the base pan, an upper pad extending from the lower pad along the vertical direction and contacting a bottom surface of the compressor, and at least one stopping feature defined on the lower pad or the upper pad, the at least one stopping feature engaging the at least one alignment feature to prevent rotation of the damper.