HVAC BURNER ASSEMBLY AND A METHOD THEREOF

Abstract

A Heating Ventilation and Air Conditioning (HVAC) burner assembly is disclosed. The HVAC burner assembly includes one or more burners comprising a downstream side and an inlet disposed on an upstream side. An inlet manifold, in fluid communication with the inlet of the one or more burner, is adapted to supply a primary air-fuel mixture to the inlet of the one or more burner. At least one mechanical blower is in fluid communication with the inlet manifold. 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.

Claims

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

2. The HVAC burner assembly 100 of claim 1, wherein 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 103.

3. The HVAC burner assembly 100 of claim 1, wherein the primary air-fuel ratio of the primary air-fuel mixture is regulated based on a type of fuel.

4. The HVAC burner assembly 100 of claim 1, wherein the fuel is at least one of a hydrogen fuel and a hydrogen blended hydrocarbon fuel.

5. The HVAC burner assembly 100 according to of claim 1, wherein the inlet 101a of the one or more burner 101 comprises a venturi shaped throat.

6. The HVAC burner assembly 100 according to of claim 1, wherein a secondary inducer 104 is adapted to induce secondary air to completely combust the primary air-fuel mixture.

7. The HVAC burner assembly 100 according to of claim 1, wherein each inlet 101 a is at least one of: fastened to the inlet manifold 102; and welded to the inlet manifold 102.

8. The HVAC burner assembly 100 according to claim 1, wherein each inlet 101a forms an interface with the inlet manifold 102 upon assembling the one or more burner 101 to the inlet manifold 102.

9. The HVAC burner assembly 100 according to claim 8, wherein each interface is sealed.

10. The HVAC burner assembly 100 according to claim 1, wherein the downstream side of the one or more burner 101 is in fluid communication with a heat exchanger tube 105.

11. The HVAC burner assembly 100 according to claim 1, wherein at least one of the downstream side of the one or more burner 101 and an inlet of each heat exchanger tube 105 is adapted to generate a turbulent flow of the secondary air induced by the secondary inducer 104.

12. A method 200 of operating an HVAC burner assembly 100, the method 200 comprising: providing the HVAC burner assembly 100 comprising: one or more burner 101; an inlet manifold 102 in fluid communication with an inlet of the one or more burner; and at least one mechanical blower 103 comprising an impeller; receiving, by the at least one mechanical blower 103, a fuel distributed from a fuel source and primary air; mixing, by the at least one mechanical blower 103, the received fuel with the primary air to generate a primary air-fuel mixture; supplying, by the at least one mechanical blower 103, the generated primary air-fuel mixture to the inlet manifold 102 in fluid communication with the at least one mechanical blower 103; supplying, by the inlet manifold 102, the primary air-fuel mixture to the inlet 101 a of the one or more burner 101; and igniting, by the one or more burner 101, the received primary air-fuel mixture.

13. The method 200 of claim 12, wherein 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 103.

14. The method 200 of claim 12, wherein the primary air-fuel ratio of the primary air-fuel mixture is regulated based on a type of fuel.

15. The method 200 of claim 12, wherein the fuel is at least one of a hydrogen fuel and a hydrogen blended hydrocarbon fuel.

16. The method 200 according to claim 12, wherein the inlet 101a of the one or more burner 101 comprises a venturi shaped throat.

17. The method 200 according to claim 12, wherein a secondary inducer 104 is adapted to induce secondary air to completely combust the primary air-fuel mixture.

18. The method 200 according to claim 12, wherein each inlet 101a is at least one of: fastened to the inlet manifold 102; and welded to the inlet manifold 102.

19. The method 200 according to claim 18, wherein each inlet 101a forms an interface with the inlet manifold 102 upon assembling the one or more burner 101 to the inlet manifold 102.

20. The method 200 according to claim 19, wherein each interface is sealed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] These and other features, aspects, and advantages will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0027] FIG. 1A illustrates a partial isometric view of an HVAC burner assembly, according to one or more embodiments of the present disclosure;

[0028] FIG. 1B illustrates a partial planar front view of the HVAC burner assembly, according to one or more embodiments of the present disclosure;

[0029] FIGS. 1C and 1D illustrate partial schematic views of the HVAC burner assembly, according to various embodiments of the present disclosure;

[0030] FIG. 1E illustrates a schematic view of the HVAC burner assembly, according to one or more embodiments of the present disclosure; and

[0031] FIG. 2 illustrates a block diagram depicting a method for operating the HVAC burner assembly.

[0032] 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.

DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Embodiments of the disclosure will be described below in detail with reference to the accompanying drawings.

[0038] A Heating, ventilation, and/or air conditioning (HVAC) burner assembly 100 for 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] FIG. 1A illustrates an isometric view of the Heating Ventilation and Air Conditioning (HVAC) burner assembly 100. FIG. 1B illustrates a planar front view of the HVAC burner assembly 100.

[0044] The Heating Ventilation and Air Conditioning (HVAC) burner assembly 100 includes one or more burners 101, an inlet manifold 102, and at least one mechanical blower 103. The one or more burners 101 includes a downstream side and an inlet 101 a disposed on an upstream side. The primary change in the HVAC burner assembly 100 is implemented in the upstream side of a throat of the one or more burner's 101 venturi. In the HVAC burner assembly 100, the geometry and velocity-based elements of the inlet 101a of the one or more burner 101 is changed as described in the subsequent paragraphs.

[0045] The inlet manifold 102 is in fluid communication with the inlet 101a of the one or more burner 101 such that the inlet manifold 102 is adapted to supply a primary air-fuel mixture (as shown by arrow P1) to the inlet 101a of the one or more burner 101. The interior of the inlet manifold 102 may be designed to optimize even distribution of the primary air-fuel mixture to the one or more burner inlet 101a. In an embodiment, each inlet 101 a is fastened and/or welded to the inlet manifold 102. Each inlet 101 a may be fastened to the inlet manifold 102 using fasteners (rivets, bolt fasteners, etc.) or industrial adhesives. Alternatively, each inlet 101a may be welded to the inlet manifold 102 using conventional welding techniques such as laser welding. In certain other implementations, each outlet of the inlet manifold 102 corresponding to each inlet 101 a may be embodied as a tube such that each tube forms an interference fit with each inlet 101 a. In yet other exemplary implementations, each inlet 101 a may be mechanically connected to the inlet manifold 102 via swage, expansion, or crimping methods.

[0046] Upon assembling the one or more burner 101 to the inlet manifold 102, each inlet 101 a forms an interface with the inlet manifold 102. For example, an outer surface of each inlet 101a may form an interface with an inner surface of each outlet of the inlet manifold 102. Alternatively, an inner surface of each inlet 101a may form an interface with an outer surface of each outlet of the inlet manifold 102. In some implementations, each interface formed between the inlet 101 a and the inlet manifold 102 is sealed using a gasket or a sealant.

[0047] In an embodiment, a secondary inducer 104 (shown in FIGS. 1C-1E) is adapted to induce secondary air (as shown by arrow S1) to completely combust the primary air-fuel mixture. The primary air-fuel mixture is forced into the Heating Ventilation and Air Conditioning (HVAC) burner assembly 100 via the at least one mechanical blower 103 and not through induced velocities. This forced air may be supplied by the at least one mechanical blower 103 which 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 blower 103 may 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 blower 103 may be fastened to the inlet manifold 102 and suitably sealed to ensure the primary air-fuel mixture is optimally supplied to each inlet 101 a of the burners 101.

[0048] In an embodiment, the fuel is injected or mixed into the primary air upstream of the inlet manifold 102. The fuel may be injected through a venturi mixing device attached to the inlet of the at least one mechanical blower 103. Although, this could be done differently, the fuel should be injected somewhere prior to entrance to the inlet manifold 102. As such, alternate embodiments may be envisioned that ensure fuel is injected or mixed into the primary air upstream of the inlet manifold 102 without departing from the scope of this disclosure.

[0049] In an embodiment, the inlet 101a of the one or more burner 101 includes a venturi shaped throat (shown as dimension t, in FIG. 1B). The at least one mechanical blower 103 is in fluid communication with the inlet manifold 102. In an embodiment, the at least one mechanical blower 103 includes 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.

[0050] The fuel gas is introduced at a single point that is through the inlet 101a via the inlet manifold 102 and 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 blower 103 and is not dependent on the geometries of the throat of the inlet 101a or the inclusion of a spoiler screw to create thorough mixing prior to combustion.

[0051] 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 103.

[0052] In an embodiment, the throat of the venturi (shown as dimension t, in FIG. 1B) of the one or more burner 101 may 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 101. Moreover, the throat of the venturi of the one or more burner 101 may 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 blower 103 may be increased to overcome the additional pressure drop caused by the narrow throat design.

[0053] In the HVAC burner assembly 100 disclosed herein, the operation of an in-shot burner system is largely unchanged downstream of the throat of the one or more burner 101. 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 assembly 100 may be implemented with minimal changes and minimal increase in costs to existing systems.

[0054] FIGS. 1C and 1D illustrates partial schematic views of the HVAC burner assembly, according to various embodiments of the present disclosure. FIG. 1E 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 burner 101 is in fluid communication with a heat exchanger tube 105. With the burner 101, the primary air/fuel mixture starts to burn but the secondary air induced by the secondary inducer 104 is provided to disrupt the inner flame (as shown by arrows F1). The secondary inducer 104 is in fluid communication with the downstream side of the one or more burner 101 via a corresponding heat exchanger tube 105. Advantageously, the introduction of secondary air to mix with the unburned fuel provides adequate oxygen for complete combustion. Since the mixer or the mechanical blower 103 in the present disclosure creates a more thorough mixture of primary air and fuel, the secondary inducer 104 performs the function of adding secondary air into the heat exchanger tube 105 in a forceful way. Another function of the secondary air is to cushion the walls of the heat exchanger tube 105 from the full heat and oxidation potential of the inner flame as the inner flame combusts completely.

[0055] 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 105. In an embodiment, several structural configurations may be defined on the burner 101 or the inlet of each heat exchanger tube 105. For example, baffles (as shown in FIG. 1D), slots (as shown in FIG. 1C), protrusions, channels, flow pathways may be defined on at least one of the downstream side of the one or more burner 101 and the inlet of each heat exchanger tube 105 to generate a turbulent flow (as shown by arrows T1) of the secondary air induced by the secondary inducer 104. The increased turbulence creates a more thorough mixture of primary air and to cushion the walls of the heat exchanger tube 105 from the full heat and oxidation potential of the inner flame as the inner flame combusts completely.

[0056] FIG. 2 illustrates a block diagram depicting a method 200 for operating the HVAC burner assembly 100.

[0057] The method 200 of operating the HVAC burner assembly 100, includes at step 201, providing the HVAC burner assembly 100 described in the detailed description of FIGS. 1A-1B.

[0058] The method 200 includes, at step 202, receiving, by the at least one mechanical blower 103, the fuel distributed from a fuel source and primary air. In an embodiment, the fuel is at least one of a hydrogen fuel and a hydrogen blended hydrocarbon fuel. In an embodiment, the fuel is injected or mixed into the primary air upstream of the inlet manifold 102. The fuel may be injected through a venturi mixing device (not shown) attached to the inlet of the at least one mechanical blower 103. Although, this could be done differently, the fuel should be injected somewhere prior to entrance to the inlet manifold 102. As such, alternate embodiments may be envisioned that ensure fuel is injected or mixed into the primary air upstream of the inlet manifold 102 without departing from the scope of this disclosure.

[0059] The method 200 includes, at step 203, mixing, by the at least one mechanical blower 103, the received fuel with the primary air to generate the primary air-fuel mixture. The primary air-fuel ratio of the primary air-fuel mixture is regulated based on the type of fuel.

[0060] The method 200 includes, at step 204, supplying, by the at least one mechanical blower 103, the generated primary air-fuel mixture to the inlet manifold 102 in fluid communication with the at least one mechanical blower 103. In an embodiment, at least one of the velocity, the pressure, and the 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 103.

[0061] The method 200 includes, at step 205, supplying, by the inlet manifold 102, the primary air-fuel mixture to the inlet 101a of the one or more burner 101. In an embodiment, the inlet 101a of the one or more burner 101 includes the venturi shaped throat. Each inlet 101a is at least one of fastened to the inlet manifold 102 and welded to the inlet manifold 102. Moreover, each inlet 101a forms an interface with the inlet manifold 102 upon assembling the one or more burner 101 to the inlet manifold 102. Each interface is sealed.

[0062] The method 200 includes, at step 206, igniting, by the one or more burner 101, the received primary air-fuel mixture. The secondary inducer 104 is adapted to induce secondary air to completely combust the primary air-fuel mixture.

[0063] The HVAC burner assembly 100 disclosed herein has several advantages as will be discussed in the subsequent paragraphs in this disclosure. The HVAC burner assembly 100 eliminates the use of precise geometry and gas velocity relationships that make the complete mixing of the appropriate primary air and the fuel gas occur. Moreover, the HVAC burner assembly 100 also intends to eliminate the geometric constraints of the venturi throat which is constrained by the venturi effect and air friction to prevent the potential flashback of a wide variety of fuels.

[0064] The HVAC burner assembly 100 also allows complete mixing of the fuel and primary air inside a blower system, such as the mechanical blower 103, without the normal geometric constraints. Furthermore, the HVAC burner assembly 100 allows the low-cost heat exchangers used with existing in-shot burners to remain useful for a pure hydrogen or hydrogen-blend application. The HVAC burner assembly 100 also allows for the application of propane and natural gas with little to no physical conversion. In such an embodiment, a restrictor orifice may be implemented to reduce the volume flow rate of propane compared to natural gas (NG) depending on the selected gas valve and technology.

[0065] Advantageously, the HVAC burner assembly 100 enables easier application of automated air and fuel ratio adjustments needed for furnaces that are self-configuring. Moreover, in an embodiment the HVAC burner assembly 100 applies a negatively regulated gas valve/venturi to the product which adds redundancies of safety that prevent the flow of gas to the system without a vacuum pulling at the at least one mechanical blower 103. Although, this could be done differently, the fuel may be injected somewhere prior to entrance to the inlet manifold 102. As such, alternate embodiments may be envisioned that ensure fuel is injected or mixed into the primary air upstream of the inlet manifold 102 without departing from the scope of this disclosure.

[0066] As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.

[0067] Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts.

[0068] The drawings and the forgoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein.

[0069] Benefits, other advantages, and solutions to problems have been described above regarding specific embodiments. However, the benefits, advantages, solutions to problems, and any component(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, or essential feature or component of any or all the claims.