Hvac Burner Assembly and a Method Thereof

The application claims the benefit of U.S. Provisional Application No. 63/634,447 filed Apr. 15, 2024, the contents of which are hereby incorporated in their entirety.

The disclosure generally relates to Heating, ventilation, and/or air conditioning (HVAC) furnaces. More particularly, the disclosure relates to an HVAC burner assembly for an HVAC furnace.

Heating, ventilation, and/or air conditioning (HVAC) furnaces are widely used in commercial and residential environments for heating and otherwise conditioning interior spaces. Conventionally, HVAC furnaces are designed for specific fuels such as natural gas (NG) or propane.

This summary is provided to introduce a selection of concepts in a simplified format that are further described in the detailed description of the disclosure. This summary is not intended to identify key or essential inventive concepts of the disclosure, nor is it intended for determining the scope of the disclosure.

Disclosed herein is a Heating Ventilation and Air Conditioning (HVAC) burner assembly. The HVAC burner assembly includes one or more burners, an inlet manifold, and at least one mechanical blower. The one or more burner comprising a downstream side and an inlet disposed on an upstream side. The inlet manifold is in fluid communication with the inlet of the one or more burner such that the inlet manifold is adapted to supply a primary air-fuel mixture to the inlet of the one or more burner. The at least one mechanical blower is in fluid communication with the inlet manifold. Moreover, the at least one mechanical blower includes an impeller adapted to receive and mix a fuel with primary air for generating the primary air-fuel mixture.

In one or more embodiments according to the disclosure, at least one of a velocity, a pressure, and a primary air-fuel ratio of the primary air-fuel mixture is regulated by adjusting one or more parameters of the at least one mechanical blower.

In one or more embodiments according to the disclosure, the primary air-fuel ratio of the primary air-fuel mixture is regulated based on a type of fuel.

In one or more embodiments according to the disclosure, the fuel is at least one of a hydrogen fuel and a hydrogen blended hydrocarbon fuel.

In one or more embodiments according to the disclosure, the inlet of the one or more burner includes a venturi shaped throat.

In one or more embodiments according to the disclosure, a secondary induceris adapted to induce secondary air to completely combust the primary air-fuel mixture.

In one or more embodiments according to the disclosure, each inlet is at least one of fastened to the inlet manifold and welded to the inlet manifold.

In one or more embodiments according to the disclosure, each inlet forms an interface with the inlet manifold upon assembling the one or more burner to the inlet manifold.

In one or more embodiments according to the disclosure, each interface is sealed.

In one or more embodiments according to the disclosure, the downstream side of the one or more burner is in fluid communication with a heat exchanger tube.

In one or more embodiments according to the disclosure, at least one of the downstream side of the one or more burner and an inlet of each heat exchanger tube is adapted to generate a turbulent flow of the secondary air induced by the secondary inducer.

Also disclosed herein is a method of operating an HVAC burner assembly. The method includes providing the HVAC burner assembly including one or more burners, an inlet manifold in fluid communication with an inlet of the one or more burners, and at least one mechanical blower including an impeller. Then, the method includes receiving, by the at least one mechanical blower, a fuel distributed from a fuel source and primary air. Next, the method includes mixing, by the at least one mechanical blower, the received fuel with the primary air to generate a primary air-fuel mixture. Subsequently, the method includes supplying, by the at least one mechanical blower, the generated primary air-fuel mixture to the inlet manifold in fluid communication with the at least one mechanical blower. Thereafter, the method includes supplying, by the inlet manifold, the primary air-fuel mixture to the inlet of the one or more burner. Finally, the method includes igniting, by the one or more burner, the received primary air-fuel mixture.

In one or more embodiments according to the disclosure, at least one of a velocity, a pressure, and a primary air-fuel ratio of the primary air-fuel mixture is regulated by adjusting one or more parameters of the at least one mechanical blower.

In one or more embodiments according to the disclosure, the primary air-fuel ratio of the primary air-fuel mixture is regulated based on a type of fuel.

In one or more embodiments according to the disclosure, the fuel is at least one of a hydrogen fuel and a hydrogen blended hydrocarbon fuel.

In one or more embodiments according to the disclosure, the inlet of the one or more burner includes a venturi shaped throat.

In one or more embodiments according to the disclosure, a secondary induceris adapted to induce secondary air to completely combust the primary air-fuel mixture.

In one or more embodiments according to the disclosure, each inlet is at least one of fastened to the inlet manifold and welded to the inlet manifold.

In one or more embodiments according to the disclosure, each inlet forms an interface with the inlet manifold upon assembling the one or more burner to the inlet manifold.

In one or more embodiments according to the disclosure, each interface is sealed.

To further clarify the advantages and features of the method and system, a more particular description of the method and system will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawing. It is appreciated that these drawings depict only typical embodiments of the disclosure and are therefore not to be considered limiting its scope. The disclosure will be described and explained with additional specificity and detail with the accompanying drawings.

Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the disclosure. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the disclosure so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the various embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the disclosure relates.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the disclosure and are not intended to be restrictive thereof.

Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Thus, appearances of the phrase “in an embodiment”, “in another embodiment”, “some embodiments”, “one or more embodiments” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or sub-systems or elements or structures or components proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components.

Embodiments of the disclosure will be described below in detail with reference to the accompanying drawings.

A Heating, ventilation, and/or air conditioning (HVAC) burner assemblyfor an HVAC furnace, disclosed herein, is an improvement on the design of an in-shot burner technology for the narrow range of fuels for which the in-shot burner is designed.

Existing residential furnaces are designed to operate on either natural gas (NG) or propane. Existing in-shot burners are limited to a range of effective operation by such constraints as burner entrance and throat geometries, gas orifice dimensions and gas manifold pressures that are designed for specific fuels having known characteristics. When installing such equipment, it is the responsibility of the installer to know the orifice dimensions and gas manifold pressure required to correctly operate the burners based on information extracted from lookup tables provided by the equipment manufacture. The information includes, for example, but is not limited to details of the orifice dimensions and gas manifold pressures for different gases. Moreover, the orifice dimensions and exit pressures are different for gases at different altitudes and for gases having different specific gravities and/or heating capacities. This complexity in the design of existing burners makes them dependent on user setup and not flexible enough to handle large variations in installed environments. Moreover, the design makes existing burners less flexible for use with different gases.

For example, when a burner is used for propane, an orifice pressure and a gas manifold pressure must be adjusted according to the installation instructions. Additionally, a screw may be deployed through a center of a burner venturi throat to create better mixing with a lower volume and higher density of propane (compared to NG). To deliver the appropriate primary air, the gas leaving the orifice must remain in a narrow range of velocities to cause the primary air to be induced through the venturi throat of the burner. This velocity produces the right primary air because of two factors including the designed/manufactured geometries of the burner and the correct gas orifice and gas manifold pressure set by the installer. As would be gathered by the abovementioned considerations, all the work is placed on the installer to get the mixing correct based on utility gas quality and altitude. Consequently, the involvement of highly skilled personnel for installation and subsequent maintenance of the existing HVAC furnaces increases warranty costs.

With the introduction of hydrogen blended into natural gas or pure hydrogen gas as fuel, the geometry of the existing in-shot burner designed to run on natural gas or propane is incompatible with the pure hydrogen fuel or blended fuels with high molar compositions of hydrogen. As used herein, the term “geometry” of the burner may refer to a dimension of the orifice, a distance to the burner, a diameter of a venturi inlet, a thickness or diameter of a venturi throat, a dimension of a venturi exit, etc. Since the geometry of the one or more burner is calibrated for the type of fuel that is being used in the HVAC furnace, modifying the burner for each fuel means customizing the geometry of the one or more burner based on the type of fuel flowing therethrough.

This approach increases the complexity of the burner and increases warranty costs due to deployment of highly skilled personnel for servicing and maintenance of such burners. Typically, the useful life of existing residential furnaces is about 20 to 25 years. Therefore, increasing servicing and maintenance costs during the life of the residential furnace may hinder existing customers from transitioning towards using hydrogen fuel that has lower emissions. Moreover, improvements in the burner means the solution becomes prohibitively expensive to implement in existing residential furnaces. This is because the geometry of the burner may be customized based on, for example, the altitude, the gas pressure, the primary air-fuel ratio, etc. The increased costs incurred due to such modifications may prevent households using existing furnaces to implement the solution. This means that lesser households transition to using hydrogen fuel which is environment friendly and generates lower emissions.

illustrates an isometric view of the Heating Ventilation and Air Conditioning (HVAC) burner assembly.illustrates a planar front view of the HVAC burner assembly.

The Heating Ventilation and Air Conditioning (HVAC) burner assemblyincludes one or more burners, an inlet manifold, and at least one mechanical blower. The one or more burnersincludes a downstream side and an inleta disposed on an upstream side. The primary change in the HVAC burner assemblyis implemented in the upstream side of a throat of the one or more burner'sventuri. In the HVAC burner assembly, the geometry and velocity-based elements of the inletof the one or more burneris changed as described in the subsequent paragraphs.

The inlet manifoldis in fluid communication with the inletof the one or more burnersuch that the inlet manifoldis adapted to supply a primary air-fuel mixture (as shown by arrow P) to the inletof the one or more burner. The interior of the inlet manifoldmay be designed to optimize even distribution of the primary air-fuel mixture to the one or more burner inlet. In an embodiment, each inleta is fastened and/or welded to the inlet manifold. Each inleta may be fastened to the inlet manifoldusing fasteners (rivets, bolt fasteners, etc.) or industrial adhesives. Alternatively, each inletmay be welded to the inlet manifoldusing conventional welding techniques such as laser welding. In certain other implementations, each outlet of the inlet manifoldcorresponding to each inleta may be embodied as a tube such that each tube forms an interference fit with each inleta. In yet other exemplary implementations, each inleta may be mechanically connected to the inlet manifoldvia swage, expansion, or crimping methods.

Upon assembling the one or more burnerto the inlet manifold, each inleta forms an interface with the inlet manifold. For example, an outer surface of each inletmay form an interface with an inner surface of each outlet of the inlet manifold. Alternatively, an inner surface of each inletmay form an interface with an outer surface of each outlet of the inlet manifold. In some implementations, each interface formed between the inleta and the inlet manifoldis sealed using a gasket or a sealant.

In an embodiment, a secondary inducer(shown in) is adapted to induce secondary air (as shown by arrow S) to completely combust the primary air-fuel mixture. The primary air-fuel mixture is forced into the Heating Ventilation and Air Conditioning (HVAC) burner assemblyvia the at least one mechanical blowerand not through induced velocities. This forced air may be supplied by the at least one mechanical blowerwhich may include a single-speed blower, a multi-speed blower, or a variable-speed blower depending on the product features. In an embodiment, the at least one mechanical blowermay include an inlet configured to receive fuel gas and an outlet adapted to supply the primary air-fuel mixture. The outlet of the at least one mechanical blowermay be fastened to the inlet manifoldand suitably sealed to ensure the primary air-fuel mixture is optimally supplied to each inleta of the burners.

In an embodiment, the fuel is injected or mixed into the primary air upstream of the inlet manifold. The fuel may be injected through a venturi mixing device attached to the inlet of the at least one mechanical blower. Although, this could be done differently, the fuel should be injected somewhere prior to entrance to the inlet manifold. As such, alternate embodiments may be envisioned that ensure fuel is injected or mixed into the primary air upstream of the inlet manifoldwithout departing from the scope of this disclosure.

In an embodiment, the inletof the one or more burnerincludes a venturi shaped throat (shown as dimension t, in). The at least one mechanical bloweris in fluid communication with the inlet manifold. In an embodiment, the at least one mechanical blowerincludes an impeller adapted to receive and mix a fuel with primary air for generating the primary air-fuel mixture. In an embodiment, the fuel is at least one of a hydrogen fuel and a hydrogen blended hydrocarbon fuel. The hydrogen blended hydrocarbon fuel may include hydrogen blended natural gas (NG), hydrogen blended propane fuel, gaseous biofuels, renewable natural gas, syngas, etc.

The fuel gas is introduced at a single point that is through the inletvia the inlet manifoldand not through individual orifices. Consequently, the velocity of the fuel gas has no intended impact on the amount of primary air mixed with the fuel. In an embodiment, the mixing of the primary air and fuel gas is completed in the impeller of the at least one mechanical blowerand is not dependent on the geometries of the throat of the inletor the inclusion of a spoiler screw to create thorough mixing prior to combustion.

In an embodiment, at least one of a velocity, a pressure, and a primary air-fuel ratio of the primary air-fuel mixture is regulated by adjusting one or more parameters of the at least one mechanical blower. The one or more parameters may include, but is not limited to, a fan speed, a quantity of fuel gas introduced into the blower, a quantity of air introduced into the impeller, etc. The primary air-fuel ratio of the primary air-fuel mixture is regulated based on the type of fuel. For example, the primary air-fuel ratio for a hydrogen fuel may be distinct from the primary air-fuel ratio for a hydrogen blended hydrocarbon fuel. As such regulating valves may be optionally implemented to control the quantity of fuel gas and/or the quantity of air introduced into the impeller of the at least one mechanical blower.

In an embodiment, the throat of the venturi (shown as dimension t, in) of the one or more burnermay be designed to accommodate a wide variety of flame speeds of primary air-fuel mixtures to ensure that burning cannot occur on the upstream side of the throat of the one or more burner. Moreover, the throat of the venturi of the one or more burnermay be designed to prevent burning in areas that cause oxidation or thermal issues. Alternatively, if the throat is designed to be narrow, the speed of the at least one mechanical blowermay be increased to overcome the additional pressure drop caused by the narrow throat design.

In the HVAC burner assemblydisclosed herein, the operation of an in-shot burner system is largely unchanged downstream of the throat of the one or more burner. This approach prevents changes in the design and materials used for an ignition system, a flame proving system, and a secondary air introduction. Since these components of the system are robust and cost-optimized, the changes made on the upstream side alone mean that the improved HVAC burner assemblymay be implemented with minimal changes and minimal increase in costs to existing systems.

illustrates partial schematic views of the HVAC burner assembly, according to various embodiments of the present disclosure.illustrates a schematic view of the HVAC burner assembly, according to one or more embodiments of the present disclosure. The downstream side of the one or more burneris in fluid communication with a heat exchanger tube. With the burner, the primary air/fuel mixture starts to burn but the secondary air induced by the secondary induceris provided to disrupt the inner flame (as shown by arrows F). The secondary induceris in fluid communication with the downstream side of the one or more burnervia a corresponding heat exchanger tube. Advantageously, the introduction of secondary air to mix with the unburned fuel provides adequate oxygen for complete combustion. Since the mixer or the mechanical blowerin the present disclosure creates a more thorough mixture of primary air and fuel, the secondary inducerperforms the function of adding secondary air into the heat exchanger tubein a forceful way. Another function of the secondary air is to cushion the walls of the heat exchanger tubefrom the full heat and oxidation potential of the inner flame as the inner flame combusts completely.

The provision of the secondary air ensures optimum turbulence allowing layering and cushioning around the inner flame thereby keeping the inner flame from impinging on the metals at the entrance to the heat exchanger tube. In an embodiment, several structural configurations may be defined on the burneror the inlet of each heat exchanger tube. For example, baffles (as shown in), slots (as shown in), protrusions, channels, flow pathways may be defined on at least one of the downstream side of the one or more burnerand the inlet of each heat exchanger tubeto generate a turbulent flow (as shown by arrows T) of the secondary air induced by the secondary inducer. The increased turbulence creates a more thorough mixture of primary air and to cushion the walls of the heat exchanger tubefrom the full heat and oxidation potential of the inner flame as the inner flame combusts completely.

illustrates a block diagram depicting a methodfor operating the HVAC burner assembly.