Patent ID: 12235012

DETAILED DESCRIPTION

Some implementations of the present disclosure will now be described more fully hereinafter with reference to the accompanying figures, in which some, but not all implementations of the disclosure are shown. Indeed, various implementations of the disclosure may be embodied in many different forms and should not be construed as limited to the implementations set forth herein; rather, these example implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

For example, unless specified otherwise or clear from context, references to first, second or the like should not be construed to imply a particular order. A feature described as being above another feature (unless specified otherwise or clear from context) may instead be below, and vice versa; and similarly, features described as being to the left of another feature may instead be to the right, and vice versa. Also, while reference may be made herein to quantitative measures, values, geometric relationships or the like, unless otherwise stated, any one or more if not all of these may be absolute or approximate to account for acceptable variations that may occur, such as those due to engineering tolerances or the like.

As used herein, unless specified otherwise or clear from context, the “or” of a set of operands is the “inclusive or” and thereby true if and only if one or more of the operands is true, as opposed to the “exclusive or” which is false when all of the operands are true. Thus, for example, “[a] or [b]” is true if [a] is true, or if [b] is true, or if both [a] and [b] are true. Further, the articles “a” and “an” mean “one or more,” unless specified otherwise or clear from context to be directed to a singular form. Like reference numerals refer to like elements throughout.

As used herein, the terms “bottom,” “top,” “upper,” “lower,” “upward,” “downward,” “rightward,” “leftward,” “interior,” “exterior,” and/or similar terms are used for ease of explanation and refer generally to the position of certain components or portions of the components of embodiments of the described disclosure in the installed configuration (e.g., in an operational configuration, such as located at a residence or building). It is understood that such terms are not used in any absolute sense.

Example implementations of the present disclosure relate generally to an improved HVAC device and components thereof that attenuate low-frequency noise, and thus may result in a quieter device. Example implementations will be primarily described in conjunction with furnaces used in HVAC applications, but it should be understood that example implementations may be utilized in conjunction with a variety of other applications. For example, other HVAC devices include, but are not limited to, indoor units, outdoor units, heaters (electric or otherwise), heat pumps, transport units, variable air volume units (VAVs), power induction units (PIUs), boilers as well as other devices generally including water heaters, kitchen appliances, and the like may utilize the system and method described herein.

Example embodiments of the present disclosure utilize acoustic metamaterial layers, sometimes in the form of panels, coupled to an HVAC device in order to improve the acoustical performance while minimizing potential impact on the general functionality of the HVAC device. This is achieved, in part, by strategically locating acoustic metamaterial layers, varying the thickness or number of layers, tuning the material to attenuate sound at certain frequencies bands, and other techniques discussed herein. Furthermore, the embodiments herein account for the other characteristics associated with HVAC devices, including but not limited to, fluid flow characteristics (e.g., static pressure drop, turbulence, etc.), heat transfer properties, electrical requirements, and other aspects of the HVAC device that may be impacted by the acoustical components associated with the embodiments disclosed herein.

One example embodiment includes a furnace design. An overview of this embodiment is provided followed by a more detailed discussion of the features associated with this disclosure. In some embodiments, the improved furnace includes a combustion air chamber, heat exchanger chamber, and a circulation blower chamber located within a furnace housing. In some embodiments, each of these chambers includes various sound producing components. In some embodiments, the combustion air chamber includes a burner assembly and a combustion air fan, which both may produce sound when the furnace is in operation. In some embodiments, the furnace includes sound attenuation features designed to attenuate sound emanating from the combustion air chamber. In some embodiments, the sound attenuation features include a sound attenuation layer comprising acoustic metamaterial. In some embodiments, the acoustic metamaterial is tuned to attenuate sound at a given frequency band, potentially a first frequency band. In some embodiments, this frequency band includes the operating frequency of the burner assembly and/or the combustion air fan within the combustion air chamber. In some embodiments, the furnace housing includes various housing openings. In some embodiments, the housing openings connect the interior of the various chambers within the housing to an ambient environment. For example, in some embodiments, the housing openings fluidly connect the interior of the combustion air chamber to the ambient environment. In some embodiments, the housing openings provide less sound attenuation than the housing itself for sound emanating from within or through the combustion air chamber. In some embodiments, the sound attenuation layer is coupled to the combustion air chamber and only covers a portion of the combustion air chamber. In some embodiments, the sound attenuation layer does not cover one or more of the housing openings associated with the combustion air chamber.

In some embodiments, the various sound attenuating components of this disclosure are incorporated within a kit. In some embodiments, this kit is designed to couple to an existing HVAC device, potentially a furnace, with minimal impact to the overall heating performance of the existing HVAC device. In some embodiments, the kit includes a plurality of sound attenuation panels. In some embodiments, the sound attenuation panels comprise acoustic metamaterial, and in some embodiments, the acoustic metamaterial is designed to attenuate sound at a frequency band, potentially a first frequency band. In some embodiments, the frequency band covers the frequency of operation of various sound producing components within an HVAC enclosure. In some embodiments, the frequency band covers the frequency of operation of a burner assembly and/or a combustion air fan within a combustion air chamber of a furnace. In some embodiments, the sound attenuation panels are designed to couple to the existing housing and/or structure of an HVAC device. In some embodiments, the kit includes a replacement cover designed to replace an existing door or panel of the housing associated with the HVAC device. In some embodiments, the replacement cover is designed to adjust the geometry of the housing in some manner. In some embodiments, the replacement cover is designed to enlarge the housing size to accommodate at least one sound attenuation panel. In some embodiments, the replacement cover enlarges the housing size in a manner that is equal to or larger than the size of the sound attenuation panel configured to couple to the replacement cover. In some embodiments, the housing of the HVAC device includes one or more openings that fluidly couple the interior of the housing and/or chamber within the housing to an ambient environment. In some embodiments, the sound attenuation panels couple to a housing and/or chamber within the housing such that they only cover a portion of the housing and/or chamber. In some embodiments, the sound attenuation panels are configured such that they do not cover one or more housing openings associated with the housing and/or chamber.

Referring now toFIGS.1-3, example embodiments of a gas-fired furnace100are shown that may utilize the improved sound attenuation features disclosed in the present application. As discussed herein, furnace100may be referred to as being “gas-fired”, where the “gas-fired” furnace is configured to be in fluid communication with a gas supply for thermodynamic heat transfer. In some embodiments, furnace100may comprise components of an HVAC system that includes an indoor unit comprising furnace100or an outdoor unit. Furnace100may be configured as an indoor furnace that provides conditioned fluid, often air, to a comfort zone of an indoor space. However, in general, the components of furnace100may be equally employed in an outdoor or weatherized furnace to condition an indoor space. Moreover, furnace100may be used in residential or commercial applications.

FIG.1shows a schematic of an example enclosure105that may be implemented with the furnace100in some embodiments. The enclosure105, potentially a housing, has an interior space110that may be partitioned into a plurality of chambers: a heat exchanger chamber115, a circulation blower chamber120, and a combustion chamber125.FIG.1further shows how the chambers may be arranged within the furnace100.

FIGS.2and3show schematics of various components that may be included within furnace100. In the embodiments depicted inFIGS.2and3, furnace100includes a burner assembly205, a heat exchanger assembly210, a combustion air blower215, a circulation air blower220, multiple controllers, and other associated components. In the embodiments shown inFIGS.2and3, the combustion air flow follows a combustion air flow path (indicated by arrow225) that may be in a direction beginning at the air/fuel mixing unit230, extending through various components to the combustion air blower215. The combustion air flow path225continues to an exhaust conduit (not shown inFIGS.2and3).

In some embodiments, the combustion air flow described above may be introduced into furnace100by a fan or blower. This blower may be a draft inducer (as shown inFIGS.2and3) when the blower is operating in an induced draft mode and pulling the combustion air flow through furnace100, or the blower may be a forced draft blower when the blower is operating in a forced draft mode and pushing the combustion air flow through furnace100. In the depicted embodiments, the combustion air blower215is in fluid communication with combustion air flow path225and is downstream of heat exchanger assembly210, which in some embodiments includes a secondary heat exchanger270. Embodiments using a forced draft mode may be accomplished by placing a blower at the inlet of air/fuel mixing unit230and forcing the gas flow into and through air/fuel mixing unit230and along combustion air flow path225.

In the depicted embodiment, the burner assembly205may include an air fuel mixing unit230, manifold235, and one or more burners240. The heat exchanger assembly210may include a first heat exchanger end245coupled to intake manifold235and a second heat exchanger end255coupled to hot collector box260, and a plurality of heat exchanger tubes265. In some embodiments, a finned condensing heat exchanger270may extend from the hot collector box260to the combustion air blower215. However, generally, furnace100may be operated with or without a condensing heat exchanger as a “condensing” or “non-condensing” furnace, respectively. Some embodiments, for example some non-condensing furnace embodiments, may also arrange the various components discussed above in other configurations. For example, in some embodiments, the combustion air may enter into the heat exchanger chamber in the lower section and the combustion air may flow upwards through the heat exchanger tubes, exiting the heat exchanger chamber at an upper section. In these embodiments, the burner assembly may be located in the middle portion of the combustion air chamber and the combustion air blower may be located near the upper section.FIGS.6and7show example embodiments of how the combustion air chamber may be configured in these embodiments. Other configurations and implementations for furnaces and other HVAC devices may also be utilized in accordance with the present disclosure.

FIGS.4A and4Bshow an angled view of an embodiment of a combustion chamber for a gas-fired furnace that may utilize the disclosure features.FIG.4Ashows an angled view of a housing300for furnace100. In the depicted embodiment, the housing300encloses the heat exchanger chamber115, the blower chamber120(shown inFIG.2), and the combustion chamber125(shown inFIG.4B). In the depicted embodiment, the housing300includes a plurality of panel walls forming the structure or part of the structure associated with the housing. In the depicted embodiment, the housing300includes a front combustion air wall panel305(potentially a door in some embodiments), side combustion air wall panels310, a top combustion air wall panel315, a bottom combustion air wall panel325(shown inFIG.4B), side heat exchanger wall panels330, side circulation air wall panels335as well as front exchanger wall panels and front circulation air wall panels (not shown) located opposite the front combustion air wall panel305. An additional side heat exchanger wall panel330and an additional side circulation blower wall panel335are located opposite the side heat exchanger wall panel330and the side circulation air wall panel335shown in the depicted embodiments. The combustion air chamber125also includes a combustion air partition380(shown inFIG.4B) separating the combustion air chamber125from the heat exchanger chamber115and the circulation air blower chamber120. The housing300also includes housing openings, which may fluidly connect one or more enclosures within the housing to the environment outside the housing. For example, the depicted embodiment includes multiple combustion air chamber openings340connecting the combustion air chamber125to the environment outside housing300. In some embodiments, a conduit or a duct may be coupled to a housing opening, for example, in the depicted embodiment, an exhaust flue345is connected to one of the combustion air openings340. In some embodiments, the housing opening may include a plurality of apertures. For example, in the depicted embodiment, a combustion air chamber opening340located on the front combustion air wall panel305contains multiple opening apertures350. In the depicted embodiment, the combustion air openings340on the side combustion air wall panel310also includes multiple opening apertures350.

The embodiment depicted inFIG.4Bshows an angled view of the combustion air chamber125with the front combustion air wall panel305removed. In the depicted embodiment, the combustion air chamber125includes a hollow space355that houses various components, including a combustion air blower360, a burner assembly365, and various other components. In the depicted embodiment, the combustion air blower360may be similar or the same as the combustion air blower215shown inFIGS.2and3, and the burner assembly365may be similar or the same as the burner assembly205shown inFIGS.2and3. In some embodiments, both the combustion air blower360and the burner assembly365are sound producing components. In some embodiments, the combustion air blower360includes a motor370and a blower chamber375, each of which produces sound. In some embodiments, the components of the burner assembly365produce sound, for example, the burners may produce sound as the air/gas mixture ignites and the mixture expands. These various components may produce noise at different frequencies, or some or all of these components may produce noise at the same or similar frequencies. In some embodiments, some or all of these components produce sound within a frequency band that includes 400 Hz to 500 Hz.

FIGS.5A and5Bshow illustrations of the structure of acoustic metamaterial layer(s) that may be utilized in some embodiments disclosed herein. The term acoustic metamaterials as used herein refers to materials containing embedded periodic resonant or non-resonant elements which modify the acoustic properties of the given material. In general, these elements modify the acoustical property by adjusting the dynamics of the sound waves propagating through the material and/or by wave scattering techniques. The embodiment depicted inFIG.5Bshows an example cross-section of acoustic metamaterial400according to some embodiments of the present disclosure. In the depicted embodiment, the acoustic metamaterial comprises alternating hard thin, perforated layers405and thicker, spacer layers410. In the depicted embodiment, the thin, perforated layer405comprises a hard material with an acoustical impedance much higher than the surrounding environment (e.g., air in some embodiments). In some embodiments, this layer comprises a polycarbonate sheet (e.g., DuPont Melinex). In other embodiments, other forms of plastic sheets or metal sheets may be used. In the depicted embodiment, the perforated layer405comprises openings or holes within the layer. The ratio of the open areas created by these holes to the overall size of the layer is sometimes referred to as the percentage of open area (“POA”). In some embodiments, the POA is between 0.1%-1.7%, potentially 1.7%. In some embodiments, the openings are arranged in a given pattern, which may or may not vary. In some embodiments, the openings are a specific geometric shape that is consistent across the layer405, and in some embodiments these openings vary.

In the depicted embodiment, the thicker layer410, potentially a spacer layer, may comprise a softer material and may be used, in part, to space the perforated layer405. In one embodiment, the thicker layer410comprises a fiberglass material (e.g., Micromat). Other materials may be used to form the thicker layer410, and in some embodiments, the materials used are porous. In the depicted embodiment, the thicker layer410provides a constant spacing between the perforated layers405, and in some embodiments, this layer is approximately ½″ and provides that amount of spacing. Other embodiments may include different dimensions for this layer410and/or different spacing. Some embodiments may not include this layer and may use air or the surrounding medium in the space between the perforated layer405.

The embodiments depicted inFIGS.5A and5Bshow an acoustic metamaterial comprising a stacked structure. In this embodiment, the stacked structure comprises an outer perforated layer405followed by the thicker, spacer layer410, and then another perforated layer405, the middle perforated layer405in the depicted embodiment. Some embodiments include a double stacked structure that comprises the first stacked structure, e.g., a first perforated layer arranged over a first thicker spacer layer arranged over a second perforated layer, and this first stacked structure is followed by a second thicker spacer layer arranged over the first stacked structure and a then a third perforated layer arranged over the second thicker spacer layer. The depicted embodiments in bothFIGS.5A and5Billustrate a doubled stacked structure. Some embodiments of the present disclosure include more or less acoustic metamaterial layers and/or stacked structures.

In some embodiments, the acoustic metamaterial400is tuned to attenuate sound over a given frequency range, preferable a lower frequency range (e.g, less than 1000 Hz). This material can be tuned to attenuate sound at a broader or narrower frequency range as well as multiple different frequencies. In some embodiments, the acoustic metamaterial400is tuned to attenuate sound from specific sound producing components. In some embodiments, these sound producing components are selected due to the frequency of noise they produce, potentially independently of the magnitude of noise created. For example, in some embodiments, the acoustic metamaterial400is tuned to attenuate sound from a given component because it produces low frequency noise (e.g., a burner assembly, a combustion air fan, etc.), but not another component that produces a greater total amount of noise (e.g., a heat exchanger assembly). In some embodiments, the material is tuned to attenuate sound at a frequency band ranging from approximately 400 Hz to 500 Hz, and in some embodiments, this frequency band covers the operating frequency of the combustion air fan and the burner assembly. This tuning may be performed in a variety of different ways. For example, in the depicted embodiment, which utilizes a stacked acoustic metamaterial configuration, the acoustic metamaterial can be tuned to a given frequency range by adjusting the POA of one or more of the perforated layers405. Adjusting the size or patterns of the openings on the perforated layer405may also impact the tuned frequency band. The spacing between these layers and/or the thickness of the thicker layer410may also impact the frequency range. Additionally, the materials used and their acoustic properties is another factor that can affect the tuned frequency in the depicted embodiment. Other methods for tuning the acoustic material are contemplated within the scope of this disclosure, and this is only one example embodiment of the acoustic metamaterial that may be used according to the disclosure herein. Accordingly, to the extent another configuration is utilized that configuration may also be tuned to attenuate sound to reduce sound in a similar manner.

FIG.6shows an embodiment of a gas-fired furnace100that includes sound attenuation features. In the depicted embodiment, the sound attenuation features are included within the combustion air chamber125, and in some embodiments, the sound attenuation features are designed to attenuate sound from sound producing components within the combustion air chamber125. In some embodiments, the sound attenuation features comprise a sound attenuation layer composed in whole or in part from acoustic metamaterial. In some embodiments, the acoustic metamaterial comprises a stacked configuration as depicted inFIGS.5A and5B. In some embodiments, the acoustic metamaterial comprises a first and a second layer of acoustic metamaterial. In the embodiment depicted inFIG.6, the sound attenuation layer comprises multiple, separate sound attenuation panels. These panels are generally planar. In some embodiments, the sound attenuation layer comprises a continuous layer of sound attenuation material. In some embodiments, the sound attenuation layer is flexible and may include bends or curves.

In some embodiments, the sound attenuation layer is tuned to attenuate sound from one or more of the sound producing components located within the combustion air chamber125. In some embodiments, the sound attenuation layer is tuned to attenuate sound from the combustion air blower360and/or the components with burner assembly365(e.g., air/fuel mixing unit, manifold, burners, etc.). The sound attenuation layers may be tuned to other components as well.

In the embodiment depicted inFIG.6, the sound attenuation layer is arranged within the combustion air chamber125in order to maximize sound absorption, particularly low-frequency noises, while minimizing impact on the operations of the furnace100. In the depicted embodiment, a portion of the sound attenuation layer is coupled to the front combustion air wall panel305. In this embodiment, this portion of the sound attenuation layer may be referred to as the front sound attenuation wall panel505. In the depicted embodiment, the front sound attenuation panel505is coupled to the interior of the front combustion air wall panel305. In the depicted embodiment, the front sound attenuation panel505spans the length and width of the front combustion air wall panel305. In some embodiments, the front sound attenuation panel505may be coupled to the exterior of the combustion air front wall panel305. In some embodiments, the front sound attenuation panel505spans only a portion of the front combustion air wall panel305. In the embodiment depicted inFIG.6, the front combustion air wall panel305is continuous and does contain any opening. In some embodiments, the combustion air wall panel305contains openings340(e.g., the embodiment shown inFIG.4A). In some embodiments, the front sound attenuation panel505contains openings (e.g., the embodiments shown inFIGS.14A-D). In some embodiments, the openings in the front sound attenuation panel505match the openings in the front combustion air wall panel305. Other configurations for the front sound attenuation panel and/or the attenuation layer coupled to the front panel of a furnace or other HVAC device are contemplated within the scope of the disclosure herein.

In the embodiment depicted inFIG.6, the sound attenuation layer includes two side sound attenuation panels coupled to the interior of both side combustion air wall panels310. In the depicted embodiment, these portions of the sound attenuation layer may be referred to as side sound attenuation panels510and515respectively. In the depicted embodiment, the side sound attenuation panels510and515are coupled to the interior of side combustion air wall panels310. In other embodiments, the side sound attenuation panels510and515may be coupled to the exterior of the side combustion air wall panels310. In some embodiments, the side sound attenuation panels510and515spans the entire width and length of the side combustion air wall panels310. In some embodiments, the side sound attenuation panels510and515contains openings.

In the depicted embodiment, the side sound attenuation panel510spans only a portion of one of the side combustion air wall panel310. In the depicted embodiment, side sound attenuation panel510spans a portion of the length of the side combustion air wall panel310. In the depicted embodiment, side sound attenuation panel510terminates a distance from an upper end312of the side combustion air wall panel310. In the depicted embodiment, the side sound attenuation panel510terminates before combustion air openings340. In the depicted embodiment, side sound attenuation panel510spans the width of the lower section of the side combustion air wall panel310. In this embodiment, the side sound attenuation panel510includes a narrow elongated portion512that extends around various components coupled to one of the side combustion air wall panels305.

In the depicted embodiment, the side sound attenuation panel515spans only a portion of one of the side combustion air wall panel310. In the depicted embodiment, side sound attenuation panel515spans a portion of the length of the side combustion air wall panel310. In the depicted embodiment, side sound attenuation panel515terminates a distance from an upper end312of the side combustion air wall panel310. In the depicted embodiment, the side sound attenuation panel515terminates before combustion air openings340. In the depicted embodiment, side sound attenuation panel515spans the width of the lower section of the side combustion air wall panel310. In this embodiment, the side sound attenuation panel515includes a narrow elongated portion516that extends around various components coupled to one of the side combustion air wall panel305. In the depicted embodiment, the elongated portion516on side sound attenuation panel515is a different length than the elongated portion512on side sound attenuation panel510. In some embodiments, the elongated portion on the side sound attenuation panels are the same length. In some embodiments, the length of the elongated portion varies between the sound attenuation panels and/or the sound attenuation panels do not include elongated portions. In the depicted embodiment, side sound attenuation panel515includes an extended portion518that extends horizontally from the elongate portion516. In the depicted embodiment, the extended portion518extends from the top edge of the elongated portion516and for only a portion of the length of the elongate portion516, creating a notch519in side sound attenuation panel515. In some embodiments, the elongated portion in one of or both side sound attenuation panel(s) includes an extended portion that widens the elongated portion in a given direction for some of all of the elongated portions length. Other configurations for the side sound attenuation panel(s) and/or the attenuation layer coupled to the side panel(s) of a furnace or other HVAC device are contemplated within the scope of the disclosure herein.

In the depicted embodiment, the sound attenuation layer includes a bottom sound attenuation panel coupled the interior of the bottom combustion air wall panel325. In the depicted embodiment, this portion of the sound attenuation layer may be referred to as the bottom sound attenuation panel520. In the depicted embodiment, the bottom sound attenuation panel520is coupled to the interior of the bottom combustion air wall panel325. In the depicted embodiment, the bottom sound attenuation panel520spans the length and width of the bottom combustion air wall panel325. In other embodiments, the bottom sound attenuation panel520may be coupled to the exterior of the bottom combustion air wall panel325. In some embodiments, the bottom sound attenuation panel520spans only a portion of the bottom combustion air wall panel325. In some embodiments, the bottom sound attenuation panel520contains openings. Other configurations for the bottom sound attenuation panel and/or the attenuation layer coupled to the bottom panel of a furnace or other HVAC device are contemplated within the scope of the disclosure herein.

In the embodiment depicted inFIG.6, the sound attenuation layer forms a discontinuous section525where the sound attenuation layer fails to cover. This discontinuous section525, i.e., the uncovered section, is formed either because the sound attenuation layer includes an opening and/or fails to extend across a given panel or structure to create a sound path. For clarity, walls or structures that do not include the sound attenuation layer are not considered a discontinuous section in this disclosure. Rather, discontinuous sections include walls or structures that include a sound attenuation layer and the sound attenuation layer is structured to create an opening or uncovered section in order to create a discontinuation section on the wall or structure. To further illustrate, in the embodiment depicted inFIG.6the discontinuous section525comprises layers where the sound attenuation layer does not cover a given wall and/or panel. In the depicted embodiment, side sound attenuation panels510and515both form discontinuous sections525along the upper portion of each side combustion air panel310. These discontinuation sections525are formed where the sound attenuation panels510and515terminate short of the length of the side combustion air panels310, which provide sections in the side combustion air panels310that do not include the sound attenuation layer. Discontinuous sections are also formed where the elongated portions512and516form an uncovered portion along the width of the side combustion air wall panel305that are not covered by the sound attenuation layer. These discontinuation sections525may provide less sound attenuation, or less sound attenuation of a given frequency band, than other sections of a given wall and/or structure. Walls or structures that do not include any sound attenuation layer are not considered discontinuous sections in the present disclosure, however, they may operate similarly. For example, in the depicted embodiment the top combustion air wall panel315is not coupled to the sound attenuation layer. In the depicted embodiment, the combustion air partition380is also not coupled to any sound attenuation layer. In some embodiments, the discontinuation sections and/or the walls and structures not including any sound attenuation layer are located at various points within the housing, chamber, or other structure in a manner that balances the need for sound attenuation via the sound attenuation layer and other considerations such as device performance, thermal characteristics, other acoustical factors, etc. The embodiment shown inFIG.6shows one illustrative configuration. Other configurations for the side sound attenuation panel(s) and/or the attenuation layer to the side panel(s) of a furnace or other HVAC device are contemplated within the scope of the disclosure herein.

In the depicted embodiment, the sound attenuation panel is attached to the panels on the combustion air chamber via magnets (not shown inFIG.6). In this embodiment, these magnets are located on the sound attenuation panels to allow support across a given panel. In some embodiments, the magnets are located on one side of the panel to ensure the panel is located appropriately. Some embodiments may utilize other coupling mechanisms. For example, in some embodiments, fasteners (e.g., screws, bolts, staples, nails, etc.) are used as coupling mechanisms, and some embodiments may include other mechanisms such as slip fits, clamps, tape, bayonet connectors, etc. In some embodiments the panels and/or walls include sound attenuation layers incorporated within the panel and/or wall.

The embodiment depicted inFIG.7illustrates another embodiment of a furnace utilizing sound attenuation features. In the depicted embodiment, the furnace includes two sound attenuation layers. In the depicted embodiment, a layer550is coupled to the combustion air blower and a layer555is coupled to the burner assembly. In the depicted embodiment, the combustion air blower layer550is coupled to the motor370. In other embodiments, layer550may be coupled to both the motor370and blower compartment375, and in other embodiments, it is only coupled to the blower compartment375. In the depicted embodiment, the layer555is coupled to the burner assembly335. In some embodiments, layer555is coupled to some or all of the following components: air/gas mixing unit230, manifold235, and/or burners240. This disclosure contemplates other sound attenuation layers and/or configurations may be used.

In the embodiment depicted inFIG.7, the sound attenuation layers550and555are tuned to attenuate sound within the frequency range that includes the operating frequency of the motor370and the burners240. In some embodiments, layer550is tuned to attenuate sound within a narrower frequency band, potentially one that only includes the frequency of operation of the motor370. In some embodiments, layer555is tuned to attenuate sound at a narrower frequency band, potentially one that only includes the frequency of operation of the burners240. In some embodiments, layer550and/or layer555are tuned to cover a broader frequency band. In some embodiments, the sound attenuation layers are tuned to cover a frequency band that overlaps. In some embodiments, sound attenuation layers are tuned to cover non-overlapping frequency bands. This disclosure, however, contemplates a variety of different sound attenuation layers tuned to attenuate sound from the same or different frequency bands which may include sound produced by any of the elements discussed above or other components utilized by the HVAC device.

FIG.8shows an example embodiment of a sample sound attenuation kit600that may be used to improve the sound attenuation of an HVAC device, potentially an existing HVAC device. In the depicted embodiment, kit600includes a replacement cover605, a first sound attenuation panel610, a second sound attenuation panel615, third sound attenuation panel620, a fourth sound attenuation panel625, one or more brackets630, and one or more fasteners635. Other embodiments include more or less components. For example, some embodiments, may also include top sound attenuation panel(s), additional sound attenuation panels and/or sound attenuation layers, including flexible attenuation layers, additional replacement covers, and/or other components. In some embodiments, the sound attenuation kit600is configured to and couples to a furnace in the manner shown inFIG.6

FIGS.9A-Dshow an illustration of a replacement cover605. In the depicted embodiment, replacement cover605replaces the front combustion air wall panel305. The depicted replacement cover605is sized such that it has the same length and width as the front combustion air wall panel305. In the depicted embodiment, the replacement cover605includes a top and bottom flange606and608, respectively. In some embodiments, the replacement cover attaches to an existing HVAC device via the bracket630and/or a fastener635coupling the flanges606and608to an existing HVAC device, potentially the front side of the combustion compartment of a furnace. In some embodiments, the replacement cover605only covers a portion of the panel being replaced. In some embodiments, the replacement cover605attaches over an existing panel or portion of a panel. In some embodiments, the replacement cover605attaches to multiple existing walls or structures. Other configurations are contemplated within the scope of this disclosure.

In the depicted embodiment, replacement cover605includes an enlarged region640that extends, or enlarges, the overall housing size. In this embodiment, the enlarged region640is sized to receive a sound attenuating panel, potentially the front sound attenuating panel610. In the depicted embodiment, the enlarged region640is sized such that it is slightly larger than the front sound attenuating panel610, allowing the front sound attenuating panel610to fit within the enlarged region640with minimal clearance. In the depicted embodiment, the first sound attenuation panel610spans the length and width of the enlarged region640. In some embodiments, the enlarged region is sized to receive two or more sound attenuation panels. In some embodiments, the replacement cover605includes two or more enlarged regions. In some embodiments, each enlarged region within the replacement panel is configured to receive one or more sound attenuation panels. In some embodiments, one or more of the enlarged regions is configured to receive other components (e.g., electronic controllers, sensors, etc.). In some embodiments, the enlarged region is configured to arrange two or more sound attenuation panels in a given pattern. In some embodiments, the enlarged region is configured to arrange the two or more sound attenuation panels to form a discontinuous section. Other configurations and arrangements for the replacement cover are contemplated within the scope of this disclosure.

FIGS.10A-Dshow an illustration of a first sound attenuation panel610that may be used according to an embodiment of the present disclosure. In some embodiments, the first sound attenuation panel610is the same or similar to the front sound attenuation panel505discussed in connection withFIG.6.FIG.10Ashows a front view of the sound attenuation panel610. In some embodiments, this front side is configured to couple to the interior of a replacement cover and/or an existing wall of an HVAC device. In the depicted embodiment, the panel has a rectangular shape and includes a length611, a width612, and a thickness613. It also includes a frame614bordering the panel. The depicted embodiment includes magnets650, which may be used to couple the panel to the wall or structure of an HVAC device.FIG.10Bshows the side of the first sound attenuation panel610, and in the depicted embodiment, the thickness is substantially constant.FIG.10Cshows the rear view of the first sound attenuation panel610of this embodiment, and in some embodiments, this side of the sound attenuation panel610is configured to be facing the interior space of an HVAC chamber, potentially the interior space of a combustion air chamber of a furnace.FIG.10Dshows an angled view of this panel according to an embodiment of this disclosure.

In the depicted embodiment, first sound attenuation panel610is shaped to mirror the enlarged region640of the replacement cover605and is sized such that it is the same or smaller than the enlarged region640. In the depicted embodiment, the length611of the sound attenuation panel610is equal to or less than the length642of the enlarged region640. The width612of the sound attenuation panel610is equal to or less than the width641of enlarged region640. The thickness613of the sound attenuation panel610is equal to or less than the depth of the enlargement panel643. Other embodiments may include different dimensions or shapes associated with the first sound attenuation panel610. For example, in some embodiments, the first sound attenuation panel may be smaller in length or width than the replacement cover, which in some embodiments, is configured to form a discontinuous section. In some embodiments, the first sound attenuation panel includes openings within the panel to create discontinuous sections in that manner. In some embodiments, the sound attenuation panel extends beyond the replacement cover, potentially to attenuate sound from additional components. In some embodiments, the sound attenuation panel is thicker than the depth of the enlarged space. In some embodiments, the first sound attenuation panel couples to an existing panel of an HVAC device. Additional dimensions and shapes for the first sound attenuation panel are contemplated within the scope of this disclosure.

In the depicted embodiment, the first sound attenuation panel610has a substantially constant thickness throughout. In this embodiment, the sound attenuation panel610includes acoustic metamaterial comprising a double stacked configuration as shown inFIGS.5A and5B. In the embodiment depicted inFIGS.10A-D, the first sound attenuation panel610includes a double stacked configuration for the entire length and width of the panel. In some embodiments, the sound attenuation panel includes portions that have different acoustic metamaterial structures. For example, some embodiments may include a first portion that comprises acoustic metamaterial with a single stacked structure and a second portion with a double stacked structure. Other embodiments may include either a different number of portions with varying stacked configurations and/or more or less stacking structures. Different acoustic metamaterial configurations and structures are contemplated within the scope of this disclosure.

In the depicted embodiment, the first sound attenuation panel610includes multiple magnets650embedded within the frame of the panel. In some embodiments, these magnets enable the first sound attenuation panel610to couple to the replacement cover and/or given wall or structure of an HVAC device. In some embodiments, these magnets are located on one side of the panel and are configured to ensure the panel is located properly. For example, in the depicted embodiment, the magnets650are located on a front side of the panel, potentially a first side, and ensure that the front side is facing the replacement cover. In some embodiments, this configuration aligns the sound attenuation layers in a given direction. In some embodiments, this configuration aligns the panel and/or panel features appropriately relative to the HVAC device. In the depicted embodiment, magnets extend into the sound attenuation panel. In some embodiments, the magnets extend all the way through the sound attenuation panel. Some embodiments include other fastening devices, e.g., screws, nails, hook and loop fasteners, etc., which may be used to attach these panels. Other magnetic configurations, fasteners, and attachment configures are contemplated within the scope of the present disclosure.

FIGS.11A-Dshow an illustration of a second sound attenuation panel615that may be used according to an embodiment of the present disclosure. In some embodiments, the second sound attenuation panel615is the same or similar to the side sound attenuation panel515discussed in connection withFIG.6.FIG.11Ashows a front view of the sound attenuation panel615. In some embodiments, this front side is configured to couple to the interior of a replacement cover and/or an existing wall of an HVAC device. In the depicted embodiment, the panel has a generally rectangular shape with various additional features and includes a length616, a width617, and a thickness618. It also includes a frame619bordering the panel as well as magnets650at various locations on the panel, which may be used to couple the panel to the wall or structure of an HVAC device.FIG.11Bshows a side view of second sound attenuation panel615for this embodiment.FIG.11Cshows the rear view of the second sound attenuation panel615of this embodiment, and in some embodiments, this rear side may be configured to face the interior of an HVAC device.FIG.11Dshows an angled view of this panel according to an embodiment of this disclosure.

In the depicted embodiment, second sound attenuation panel615is shaped to couple to a side combustion air wall panel310, potentially the right side when facing the front panel of combustion air chamber125. In the depicted embodiment, the second sound attenuation panel615is generally rectangular shaped with various features. In the depicted embodiment, the length616of the second sound attenuation panel615is sized such that it is less than the length of the side combustion air wall panel310, and in this embodiment, this is done to allow for a discontinuous section to be located on the side combustion air wall panel310. In the depicted embodiment, the width617of the second sound attenuation panel615is sized such that it is the same or less than the width of the side combustion air wall panel310.

In the depicted embodiment, second sound attenuation panel615includes additional features. For example, in the depicted embodiment, the bottom edge660includes chamfered edges661and662, which angle the bottom edge660to the side edges663and664. In the depicted embodiment, the chamfered edge661creates a steeper angle than the chamfered edge662. In some embodiments, these chamfered edges are reversed, such that edge662creates a steeper angle than other chamfered edge661. In some embodiments, these chamfered edges create an equivalent angle. In some embodiments, these chamfered edges are designed to match features on the side combustion air panel. In some embodiments, the chamfered edges are designed to account for adjustments or damage that may have changed the dimensions of the side combustion air chamber. In some embodiments, the chamfered edges account for retrofit application of the second sound attenuation panel615into an existing HVAC system. In some embodiments, the chamfered edges create discontinuation sections. The depicted embodiment includes two chamfered edges, and some embodiments include more or less of these edges, or none at all.

The depicted embodiment also includes an elongated portion670where a narrower portion of the panel extends for a portion of the panel length or width. In the depicted embodiment, the elongated portion670includes a width671that is narrower than the overall width of the panel617. In the depicted embodiment, the elongated portion670extends directly on one side of the panel615. In some embodiments, the elongated portion extends at an angle and/or from the middle of the panel width. Some embodiments may include multiple elongated portions and/or the elongated portion may vary in direction and/or dimension. In some embodiments, the elongated portion is designed to account for components or features that may be located on or adjacent to the side combustion air panel310.

In the depicted embodiment, second sound attenuation panel615also includes an extended portion675that extends from the elongated portion670. In the depicted embodiment, the extended portion675extends from the top edge673of the second sound attenuation panel615and extends a length676that is a portion of the length of the elongated portion672. In the depicted embodiment, the thickness678of the extended portion675is narrower than the thickness618of the second sound attenuation panel615. This can be seen inFIG.11B, and in the depicted embodiment, the thickness678of the extended portion675is approximately half the thickness618of the second sound attenuation panel615. In some embodiments, the thickness678of the extended portion675is the same as the thickness618of the sound side attenuation panel615. In some embodiments, the thickness678of the extended portion675is greater than the thickness618of the majority of the sound side attenuation panel615. In the depicted embodiment, this configuration creates a notch680along one side of second sound attenuation panel615, and this notch680may comprise a discontinuous section. In some embodiments, the extended portion675extends at an angle and/or from the middle of the elongated portion670. Some embodiments may include multiple extended portions and/or the extended portion may vary in direction and/or dimension. In some embodiments, the extended portion is designed to account for components or features that may be located on or adjacent to the side sound attenuation panel305.

Other embodiments may include different dimensions or shapes associated with the second sound attenuation panel615. For example, in some embodiments, the side sound attenuation panel may span the entire length and/or width of the side combustion air wall panel, which in some embodiments, is configured to remove the discontinuous section. In some embodiments, the second sound attenuation panel615includes openings within the panel to create discontinuous sections in that manner. In some embodiments, the side sound attenuation panel extends beyond the side combustion air wall panel, potentially to attenuate sound from additional components. Additional dimensions and shapes for the side sound attenuation panel are contemplated within the scope of the disclosure.

In the depicted embodiment, the second sound attenuation panel615includes acoustic metamaterial comprising a double stacked configuration as shown inFIGS.5A and5Bfor at least a portion of the second sound attenuation panel615. In the depicted embodiment, second sound attenuation panel615varies in thickness. In this embodiment, second sound attenuation panel615includes a first portion that comprises an acoustic metamaterial layer configured in a singled stacked structure and a second portion that comprises a double stacked structure. In the depicted embodiment, extended portion675comprises an acoustic metamaterial layer in the single stacked configuration, such that the first portion comprises a first perforated sheet layer arranged over a spacer layer arranged over a second perforated sheet layer. In the depicted embodiment, the main portion619of the second sound attenuation panel615and the elongated portion670of the second sound attenuation panel615comprise a double stacked structure where a third perforated layer is arranged over a second spacer layer that is arranged over the stacked structure. As shown in the depicted embodiment, the width of the extended portion675is half the width of the main portion619and the elongated portion670because the extended portion comprises a single stack configuration for the acoustic metamaterial layer and the other portions comprise a double stack configuration. Some embodiments comprise a double stacked configuration for the entire length and width of the panel. Other embodiments may include either a different number of portions with varying stacked configurations and/or more or less stacking structures. Different acoustic metamaterial configurations and structures are contemplated within the scope of this disclosure.

In the depicted embodiment, the second sound attenuation panel615includes multiple magnets650embedded around the panel. In some embodiments, these magnets650enable the second sound attenuation panel615to couple to side combustion air wall panel310and/or a given wall or structure of an HVAC device. In some embodiments, these magnets are located on one side of the panel and are configured to ensure the panel is located properly. For example, in the depicted embodiment, the magnets650are located on a front side of the panel, potentially a first side, and ensure that side is facing the HVAC device wall panel. In some embodiments, this configuration aligns the sound attenuation layers in a given direction. In some embodiments, this configuration aligns the panel and/or panel features appropriately relative to the HVAC device. In the depicted embodiment, magnets extend into the sound attenuation panel. Some embodiments include other fastening devices, e.g., screws, nails, etc., which may be used to attach these panels. Other magnetic configurations, fasteners, and attachment configures are contemplated within the scope of the present disclosure.

FIGS.12A-Dshow an illustration of the third sound attenuation panel620that may be used according to an embodiment of the present disclosure. In some embodiments, the third sound attenuation panel620is the same or similar to the side sound attenuation panel510discussed in connection withFIG.6.FIG.12Ashows a front view of the third sound attenuation panel620. In some embodiments, this front side is configured to couple to the interior of a replacement cover and/or an existing wall of an HVAC device. In the depicted embodiment, the panel has a rectangular shape with various additional features and includes a length621, a width622, and a thickness623. It also includes a frame619bordering the panel as well as magnets650at various locations on the panel, which may be used to couple the panel to the wall or structure of an HVAC device.FIG.12Bshows a side view and the thickness623of the third sound attenuation panel620, which in the depicted embodiment is substantially constant.FIG.12Cshows the rear view of the third sound attenuation panel620of this embodiment, and in some embodiments, this rear side may be configured to face the interior of an HVAC device.FIG.12Dshows an angled view of this panel according to an embodiment of this disclosure.

In the depicted embodiment, third sound attenuation panel620is shaped to couple to a side combustion air wall panel310, potentially the left side when facing the front panel of combustion air chamber125. In the depicted embodiment, the third sound attenuation panel620is generally rectangular shaped with various features. In the depicted embodiment, the width622of the third sound attenuation panel620is sized such that it is the same or smaller than the width of the side combustion air wall panel310. In the depicted embodiment, the length621of the third sound attenuation panel620is sized such that is smaller than the length of the side combustion air wall panel310.

In the depicted embodiment, third sound attenuation panel620includes additional features. For example, in the depicted embodiment, the bottom edge685includes chamfered edges686and687, which angle the bottom edge685to the side edges688and689. In the depicted embodiment, the chamfered edge686creates a steeper angle than the chamfered edge687. In some embodiments, these chamfered edges are reversed, such that edge687creates a steeper angle than the other chamfered edge686. In some embodiments, these chamfered edges create an equivalent angle. In some embodiments, these chamfered edges are designed to match features on the side combustion air panel. In some embodiments, the chamfered edges are designed to account for adjustments or damage that may have changed the dimensions of the combustion air chamber. In some embodiments, the chamfered edges create discontinuation sections. The depicted embodiment includes two chamfered edges, and some embodiments include more or less of these edges, or none at all.

The depicted embodiment also includes an elongated portion690where a narrower portion of the panel extends for a portion of the panel length or width. In the depicted embodiment, the elongated portion690includes a width691that is narrower than the overall width622of the panel620. In the depicted embodiment, the elongated portion690extends directly along one side of the panel620. In some embodiments, the elongated portion extends at an angle and/or from the middle of the width. Some embodiments may include multiple elongated portions and/or the elongated portion may vary in shape, directions, and/or dimensions. In some embodiments, the elongated portion is designed to account for components or features that may be located on or adjacent to the side combustion air panel305.

Other embodiments may include different dimensions or shapes associated with the third sound attenuation panel620. For example, in some embodiments, the side sound attenuation panel may span the entire length and/or width of the side combustion air wall panel, which in some embodiments, is configured to remove the discontinuous section. In some embodiments, the third sound attenuation panel620includes openings within the panel to create discontinuous sections in that manner. In some embodiments, the sound attenuation panel extends beyond the side combustion air wall panel, potentially to attenuate sound from additional components. Additional dimensions and shapes for the side sound attenuation panel are contemplated within the scope of the disclosure.

In the depicted embodiment, the third sound attenuation panel620has a substantially constant thickness throughout. In this embodiment, the third sound attenuation panel620includes acoustic metamaterial comprising a double stacked configuration as shown inFIGS.5A and5B. In the embodiment depicted inFIGS.12A-D, the third sound attenuation panel620includes a double stacked configuration for the entire length and width of the panel. In some embodiments, the sound attenuation panel includes portions that have different acoustic metamaterial structures. For example, some embodiments may include a first portion that comprises acoustic metamaterial with a single stacked structure and a second portion with a double stacked structure. Other embodiments may include either a different number of portions with varying stacked configurations and/or more or less stacking structures. Different acoustic metamaterial configurations and structures are contemplated within the scope of this disclosure.

In the depicted embodiment, the third sound attenuation panel620includes multiple magnets650embedded around the panel. In some embodiments, these magnets650enable the sound attenuation panel620to couple to side combustion air wall310and/or a given wall or structure of an HVAC device. In some embodiments, these magnets are located on one side of the third sound attenuation panel and are configured to ensure the third sound attenuation panel is located properly. For example, in the depicted embodiment, the magnets650are located on a front side of the third sound attenuation panel, potentially a first side, and ensure that side is facing the HVAC wall panel appropriately. In some embodiments, this configuration aligns the sound attenuation layers in a given direction. In some embodiments, this configuration aligns the third sound attenuation panel and/or third sound attenuation panel features appropriately relative to the HVAC device. In the depicted embodiment, magnets extend into the sound attenuation panel. Other magnetic configurations, fasteners, and attachment configures are contemplated within the scope of the present disclosure.

FIGS.13A-Dshow an illustration of a fourth sound attenuation panel625that may be used according to an embodiment of the present disclosure. In some embodiments, the fourth sound attenuation panel625is the same or similar to the bottom sound attenuation panel520discussed in connection withFIG.6. In the depicted embodiment, the panel has a rectangular shape and includes a length626, a width627, and a thickness628. It also includes a frame629bordering the panel. The depicted embodiment includes magnets650, which may be used to couple the panel to the wall or structure of an HVAC device.FIG.13Bshows a side view and the thickness628of the fourth sound attenuation panel625, and in the depicted embodiment, the thickness is substantially constant.FIG.13Cshows the rear view of the fourth sound attenuation panel625of this embodiment, and in some embodiments, this side of the sound attenuation panel625is configured to be facing the interior space of an HVAC chamber, potentially the interior space of a combustion air chamber of a furnace.FIG.13Dshows an angled view of this panel according to an embodiment of this disclosure.

In the depicted embodiment, fourth sound attenuation panel625is shaped to mirror the bottom combustion air wall panel325and is sized such that it is the same or smaller than the bottom combustion air wall panel325. The fourth sound attenuation panel625is shaped such that it mirrors the bottom combustion air wall panel325. In the depicted embodiment, the length626of the sound attenuation panel625is equal to or less than the length of the bottom combustion air wall panel325. The width627of the sound attenuation panel625is equal to or less than the width of bottom combustion air wall panel325. Other embodiments may include different dimensions or shapes associated with the fourth sound attenuation panel625. For example, in some embodiments, the fourth sound attenuation panel may be smaller in length or width than the bottom combustion air panel, which in some embodiments, is configured to form a discontinuous section. In some embodiments, the fourth sound attenuation panel includes openings within the panel to create discontinuous sections in that manner. In some embodiments, the fourth sound attenuation panel extends beyond the bottom combustion air panel, potentially to attenuate sound from additional components. Additional dimensions and shapes for the fourth sound attenuation panel are contemplated within the scope of the disclosure.

In the depicted embodiment, the fourth sound attenuation panel625has a substantially constant thickness throughout. In this embodiment, the fourth sound attenuation panel625includes acoustic metamaterial comprising a double stacked configuration as shown inFIGS.5A and5B. In the embodiment depicted inFIGS.13A-D, the fourth sound attenuation panel625includes a double stacked configuration for the entire length and width of the panel. In some embodiments, the fourth sound attenuation panel includes portions that have different acoustic metamaterial structures. For example, some embodiments may include a first portion that comprises acoustic metamaterial with a single stacked structure and a second portion with a double stacked structure. Other embodiments may include either a different number of portions with varying stacked configurations and/or more or less stacking structures. Different acoustic metamaterial configurations and structures are contemplated within the scope of this disclosure.

In the depicted embodiment, the fourth sound attenuation panel625includes multiple magnets embedded within each corner of the panel. In some embodiments, these magnets enable the fourth sound attenuation panel625to couple to bottom combustion air wall panel325and/or given wall or structure of an HVAC device. In some embodiments, these magnets are located on one side of the panel and are configured to ensure the panel is located properly. For example, in the depicted embodiment, the magnets650are located on a front side of the panel, potentially a first side, and ensure that side is facing the HVAC wall appropriately. In some embodiments, this configuration aligns the sound attenuation layers in a given direction. In some embodiments, this configuration aligns the panel and/or panel features appropriately relative to the HVAC device. In the depicted embodiment, magnets extend into the sound attenuation panel. Some embodiments include other fastening devices, e.g., screws, nails, etc., which may be used to attach these panels. Other magnetic configurations, fasteners, and attachment configures are contemplated within the scope of the present disclosure.

The sound attenuation panels discussed in connection withFIGS.10-13are illustrative embodiments of sound attenuation panels that may be used according to the present disclosure. The various features and configurations discussed in these embodiments are equally applicable to each other and/or other sound attenuation panels.

FIGS.14A-Dshow illustrations of various sound attenuation protrusions which may be used in some embodiments. In the depicted embodiment,FIG.14Ashows a front view of a sound attenuation layer700that includes multiple sound attenuation protrusions705.FIG.14Bshows an illustration of a rear view of this sound attenuation layer700.FIG.14Cshows an enlarged illustration of a portion of the sound attenuation layer700and the sound attenuation protrusions705located on a portion of the front panel of an HVAC device, potentially the front panel of the combustion furnace shown inFIG.4A.

In the depicted embodiment, the sound attenuation protrusions705extend from the sound attenuation layer700and are shaped to create apertures710within the sound attenuation layer700. In the depicted embodiment, the apertures710are all consistently shaped, and in this embodiment, these apertures710are designed to match the openings715located on the front the combustion air panel720. In some embodiments, the apertures710are designed to match other openings within an HVAC device, and these apertures710may vary in size and shape. In some embodiments of these sound attenuation protrusions705may include a single aperture710, and some embodiments they are not configured to match an opening on an HVAC device. For example, these apertures may be larger or smaller than a given opening, or they may be located on a portion of the housing that does not include an opening, e.g., the aperture(s)710may align with a thermal bridge, communication pathway, etc.

FIG.14Dshows an embodiment that includes two sound attenuation layers700, each with sound attenuation protrusions705. In the depicted embodiment, these layers and protrusions match each other and are coupled to either side of the housing openings.FIG.14Dshows these two layers spaced a distance725apart.

In the depicted embodiment, the sound attenuation protrusions705extend a distance from the sound attenuation layer700, and in the depicted embodiment, the sound attenuation protrusions705extend the same distance. In some embodiments, the distance these protrusions extend is greater or lesser, and in some embodiments the distance varies. In the depicted embodiment, the sound attenuation protrusions705extend from a discrete layer700. In some embodiments, sound attenuation protrusions705may extend from any of the sound attenuation layers and/or panels discussed above. In some embodiments, the sound attenuation protrusions extend independently and are not associated with another sound attenuation layer.

In the depicted embodiment, the sound attenuation layer700and the sound attenuation protrusions705are formed from the same material. In some embodiments, the sound attenuation layer700and the sound attenuation protrusions705are formed from acoustic metamaterial. In some embodiments, the sound attenuation layer700and the sound attenuation protrusions705are formed from different material. In some embodiments, the sound attenuation protrusions are formed form plastic, metal, or other material. In some embodiments, where either the sound attenuation layer700or the sound attenuation protrusions705are composed of an acoustic metamaterial the acoustic metamaterial is tuned to attenuate sound at a frequency band that covers the frequency of operation for a given sound producing component within an HVAC device. In embodiments that include multiple sound attenuation layers comprising acoustic metamaterial, the acoustic metamaterial included in the sound attenuation layer700and/or the sound attenuation protrusions705is tuned to attenuate frequency from the same frequency band as one or more of the other sound attenuation layer(s). In other embodiments, acoustic metamaterial included in the sound attenuation layer700and/or the sound attenuation protrusions705is tuned to attenuate sound from a different band as one or more of the other sound attenuation layer(s).

Many modifications and other implementations of the disclosure set forth herein will come to mind to one skilled in the art to which the disclosure pertains having the benefit of the teachings presented in the foregoing description and the associated figures. Therefore, it is to be understood that the disclosure is not to be limited to the specific implementations disclosed and that modifications and other implementations are intended to be included within the scope of the appended claims. Moreover, although the foregoing description and the associated figures describe example implementations in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative implementations without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.