Heat exchanger assembly with a first drainage channel and a second drainage channel

Abstract

A heat exchanger assembly is provided that includes a heat exchanger plate with a first and a second set of tubes coupled thereto. An inducer pan is mounted to the heat exchanger plate and supports a draft inducer having a housing. To effectively manage liquid condensate, the assembly features a dual-drainage system. A first drainage channel is disposed at the interface between the housing of the draft inducer and the heat exchanger plate. A second drainage channel is at least partially located within the housing of the draft inducer itself. This configuration allows for the systematic collection and removal of condensate from two distinct locations within the assembly, thereby preventing moisture accumulation and protecting components from potential damage.

Description

BACKGROUND

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

The present disclosure relates generally to heating, ventilation, and air conditioning (HVAC) systems. A wide range of applications exist for HVAC systems. For example, residential, light commercial, commercial, and industrial systems are used to control temperatures and air quality in residences and buildings. Such systems often may perform heating and/or cooling functions. Very generally, these systems operate by implementing a thermal cycle in which fluids are heated and/or cooled to provide a desired temperature in a controlled space, such as within a residence or building. For example, a heat exchanger may include a coil, such as an indoor coil, configured to receive and place a fluid, such as a refrigerant, in a heat exchange relationship with an air flow to enable heat transfer between the fluid and the air flow in order to condition the air flow. The conditioned air flow may then be directed into the controlled space to condition the controlled space. A compressor of the HVAC system may be configured to bias the fluid, such as the refrigerant, to and from the heat exchanger, in addition to other componentry of the HVAC system (e.g., an additional heat exchanger, an expansion valve, etc.).

In traditional configurations, heat exchanger assemblies in HVAC systems are susceptible to the formation of liquid condensate on their exterior surfaces, especially in high-humidity conditions. This moisture accumulation may lead to corrosion of the housing and can affect nearby electrical control units, compromising system longevity. Therefore, a need exists for an improved heat exchanger design that effectively prevents condensation and manages moisture to protect the system's structural and electrical components.

SUMMARY

A summary of an embodiment disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of the embodiment and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

In an embodiment, a heat exchanger assembly is provided that comprises a heat exchanger plate, a first and second set of tubes coupled to the plate, and a draft inducer mounted to an inducer pan. To effectively manage condensate, the assembly features a dual drainage system. A first drainage channel is disposed between the housing of the draft inducer and the heat exchanger plate to remove moisture from this interface. A second drainage channel is at least partially located within the housing of the draft inducer itself to collect and guide away internally formed condensate.

In another embodiment, a heat exchanger assembly includes a heat exchanger plate with two sets of tubes and a heat shield mounted thereon. The heat shield is configured as a side wall that, in combination with the plate, defines a turnaround chamber for directing gases between the tube sets. The assembly further comprises an inducer pan mounted to the heat exchanger plate. A gasket made of an elastomeric material is disposed between the heat exchanger plate and the inducer pan to provide a robust seal and prevent leakage.

In yet another embodiment, a heat exchanger assembly is configured to protect its electronic controls. The assembly includes a heat exchanger plate, a draft inducer, a heating unit, and a control unit mounted to a panel. A thermal insulator assembly is disposed between the control unit and the heat exchanger plate, defining a substantially enclosed air gap that insulates the controls from heat and condensation. The assembly also includes an air inlet duct, partially defined by a gasket in contact with the thermal insulator assembly, which is configured to guide ambient air past the control unit to provide cooling.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present disclosure 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:

FIG. 1 is a perspective view of an HVAC unit installed on a building;

FIG. 2 is a perspective view of the internal components of a packaged HVAC unit;

FIG. 3 is a perspective view of a split residential HVAC system;

FIG. 4 is a schematic diagram of a vapor compression system;

FIG. 5 is a partial perspective view of an exemplary packaged HVAC unit illustrating various internal compartments;

FIG. 6 is an exploded perspective view of an exemplary heat exchanger assembly;

FIG. 7 is a bottom view of a draft inducer with a second drainage channel;

FIG. 8 is a perspective partial view of the heat exchanger assembly of FIG. 6 in an intermediate stage of assembly;

FIG. 9 is a partial frontal view of the heat exchanger assembly of FIG. 6 with a heating unit mounted thereto, illustrating the dual-drainage system;

FIG. 10 is a top plan view of the heat exchanger assembly and an adjacent control unit, illustrating a cooling air inlet duct; and

FIG. 11 is a partial perspective view illustrating a two-stage thermal insulating system.

DETAILED DESCRIPTION

One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers'specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be noted that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

As used herein, the terms “approximately,” “generally”, “substantially,” and so forth, are intended to convey that the property value being described may be within a relatively small range of the property value, as those of ordinary skill would understand. For example, when a property value is described as being “approximately” equal to (or, for example, “substantially similar” to) a given value, this is intended to convey that the property value may be within +/−5%, within +/−4%, within +/−3%, within +/−2%, within +/−1%, or even closer, of the given value. Similarly, when a given feature is described as being “substantially parallel” to another feature, “generally perpendicular” to another feature, and so forth, this is intended to convey that the given feature is within +/−5%, within +/−4%, within +/−3%, within +/−2%, within +/−1%, or even closer, to having the described nature, such as being parallel to another feature, being perpendicular to another feature, and so forth. Mathematical terms, such as “parallel” and “perpendicular,” should not be rigidly interpreted in a strict mathematical sense but should instead be interpreted as one of ordinary skill in the art would interpret such terms. For example, one of ordinary skill in the art would understand that two lines that are substantially parallel to each other are parallel to a substantial degree but may have minor deviation from exactly parallel.

In an embodiment, the heat exchanger assembly is specifically configured for comprehensive condensate management. The assembly comprises a heat exchanger plate, which supports a first set of tubes and a second set of tubes for the passage of gases. An inducer pan is mounted to the heat exchanger plate and includes a mounting section specifically adapted to receive a draft inducer. The draft inducer, which has its own housing, is mounted to this section of the inducer pan. To prevent the undesirable accumulation of moisture, the assembly incorporates a dual-drainage system. A first drainage channel is disposed at the interface between the housing of the draft inducer and the heat exchanger plate and is configured to collect and route away any liquid condensate that may form or collect in this region. Furthermore, a second drainage channel is located at least partially within the housing of the draft inducer itself. This second channel is configured to collect and evacuate condensate that forms internally within the draft inducer as flue gases cool. The combined action of these two distinct channels provides a robust solution for managing moisture from multiple sources, thereby protecting the assembly from corrosion and preventing liquid from reaching other sensitive system components.

In further embodiments, the heat exchanger assembly may incorporate additional features for enhanced thermal efficiency and condensate control. The assembly can include a heat shield mounted to the heat exchanger plate, which acts as a side wall to define a turnaround chamber that directs gases from the first set of tubes to the second set of tubes. To minimize heat transfer, a first gasket, which may be composed of a fiberglass material, is mounted between the heat shield and the heat exchanger plate to provide thermal insulation. The first drainage channel may be integrally formed within a second gasket, which is mounted between the heat exchanger plate and the inducer pan. This second gasket can be made of an elastomeric material to ensure a watertight seal. The second drainage channel within the draft inducer housing may be defined by at least one drain hole, and a dip pan can be disposed below to guide condensate from said drain hole safely past a heating unit. To protect electronic components, the assembly may further comprise a thermal insulator assembly disposed between a control unit and the heat exchanger plate, defining a substantially enclosed air gap. An air inlet duct, partially defined by the panel on which the control unit is mounted and a third gasket, can be configured to guide cooling ambient air past the control unit before it reaches the heating unit, thereby maintaining the control unit at a safe operating temperature. The heat exchanger plate itself may be configured with a series of inlets, outlets, and intermediate openings to which the first and second sets of tubes are connected to create the prescribed gas flow path through the assembly.

In another aspect, an embodiment of the heat exchanger assembly is provided that is specifically designed to protect heat-sensitive electronic components from thermal damage and moisture. The assembly comprises a heat exchanger plate, a draft inducer, a heating unit, and a control unit, which is mounted to a panel and configured to control the draft inducer and/or the heating unit. A thermal insulator assembly is disposed between the control unit and the heat exchanger plate, thereby defining a substantially enclosed air gap that thermally isolates the control unit from the heat-generating components. The thermal insulator assembly itself may comprise a heat shield, configured as a wall of a turnaround chamber, and a cover pan mounted indirectly to the heat shield via a thermal insulating gasket to create the aforementioned air gap. An air inlet duct is configured to guide cooling ambient air past the control unit before the air proceeds to the heating unit. This air inlet duct is partially defined by the panel and a third gasket which is in contact with the thermal insulator assembly. To ensure the integrity of this duct, an elastomeric spacer may be disposed between the panel and the third gasket, configured to bias the third gasket toward the thermal insulator assembly to create a reliable seal. In some embodiments, this thermal protection system is combined with the condensate management features, wherein the assembly further includes an inducer pan and a second gasket that comprises a first drainage channel, and may also include a second drainage channel located within the housing of the draft inducer.

Turning now to the drawings, FIG. 1 provides a general context, illustrating an HVAC system where an HVAC unit 12, such as a packaged rooftop unit, is installed on a building 10. The HVAC unit 12 conditions an air stream which is then distributed throughout the building 10 via ductwork 14. The system's operation can be regulated by a control device 16, such as a thermostat.

FIG. 2 shows a perspective view of such a packaged HVAC unit 12. A protective housing 24, which may be mounted on rails 26, encloses the internal components. These components typically include a first heat exchanger 28 (e.g., a condenser) and a second heat exchanger 30 (e.g., an evaporator) located in a separate compartment 31. Fans 32 move ambient air across the first heat exchanger 28, while a blower assembly 34, driven by a motor 36, moves the air to be conditioned across the second heat exchanger 30. The air is cleaned by filters 38 before conditioning. One or more compressors 42 circulate a working fluid, and a control board 48, receiving power via a terminal block 46 and connected by wiring 49, governs the overall operation. In some embodiments, the compressors 42 may include a pair of hermetic direct drive compressors arranged in a dual stage configuration 44. However, in other embodiments, any number of the compressors 42 may be provided to achieve various stages of heating and/or cooling.

FIG. 3 illustrates an alternative configuration, a split HVAC system 50, often used in a residence 52. This design separates the components into an outdoor unit 58 and an indoor unit 56, which are connected by working fluid conduits 54. The outdoor unit 58 typically contains a heat exchanger 60 and a fan 64. The indoor unit 56 contains a second heat exchanger 62 and a blower 66 that distributes conditioned air to the residence 52 through ductwork 68. The indoor unit 56 may also integrate a furnace system 70 for heating. Depending on the operational mode (cooling or heat pump), the roles of the heat exchangers 60 and 62 as condenser or evaporator can be reversed.

FIG. 4 is a schematic diagram illustrating the fundamental operation of a vapor compression system 72, which is the core technology for the systems shown in FIGS. 1-3. The system 72 circulates a working fluid through a closed thermodynamic circuit. The cycle begins at the compressor 74, which is driven by a motor 94 that may be powered by a variable speed drive (VSD) 92 for efficient operation. The compressor 74 pressurizes the working fluid in its vapor state and delivers it to the condenser 76. In the condenser 76, the hot, high-pressure vapor transfers heat to a separate fluid, such as ambient air 96, causing the working fluid to condense into a high-pressure liquid. This liquid then flows through an expansion device 78, where its pressure and temperature are significantly reduced. The resulting cold, low-pressure liquid enters the evaporator 80. In the evaporator 80, the liquid absorbs heat from the air stream to be conditioned (e.g., the supply air stream 98), causing the working fluid to boil and revert to a vapor. This process cools the supply air stream 98. The low-pressure vapor then returns to the suction side of the compressor 74, and the cycle repeats. The entire process is managed by a control panel 82, which may include a microprocessor 86, memory 88, an A/D converter 84, and an interface board 90.

In some embodiments, the vapor compression system 72 may further include a reheat coil in addition to the evaporator 80. For example, the reheat coil may be positioned downstream of the evaporator relative to the supply air stream 98 and may reheat the supply air stream 98 when the supply air stream 98 is overcooled to remove humidity from the supply air stream 98 before the supply air stream 98 is directed to the building 10 or the residence 52.

While various features described in detail below with reference to later drawings may be discussed in the context of a specific housing of an HVAC unit, it should be understood that the same or similar features may be implemented in any of the HVAC systems or units described above with respect to FIGS. 1-4. Additionally, while the features disclosed herein are described in the context of embodiments that directly heat and cool a supply air stream provided to a building or other load, embodiments of the present disclosure may be applicable to other HVAC systems as well.

Turning now to the figures, FIG. 5 illustrates a partial view of an exemplary single-packaged heating, ventilation, and air conditioning (HVAC) unit 100. The HVAC unit 100 comprises a main housing 102 constructed from a plurality of panels 104. These panels 104 define the exterior of the housing 102 and also form various internal compartments therein. The housing 102 further includes a duct inlet 106 for receiving a flow of air into the HVAC unit 100, and a duct outlet 108 for discharging filtered, heated, and/or cooled air from the housing 102.

The air is introduced first into a first compartment 110. The first compartment 110 comprises a fan 112, which is exemplarily mounted to an inner panel 114 of the housing 102 and directs the air from the first compartment 110 into a second compartment 116. A heat exchanger 118 is disposed within the first compartment 110. The heat exchanger 118 is connected to a compressor 120, which is arranged in an adjacent compressor compartment 121. In particular, the heat exchanger 118 is configured to cool the incoming air.

A further heat exchanger assembly 122 is disposed within the second compartment 116. The heat exchanger assembly 122 is configured to heat the air flowing through the second compartment 116. The second compartment 116 also includes the duct outlet 108, which is exemplarily arranged on the same side of the housing 102 as the duct inlet 106. However, other configurations are also contemplated. A control unit 124, which is configured to control or regulate the heat exchanger assembly 122, is also arranged within the second compartment 116. The heat exchanger assembly 122 is exemplarily configured as a fuel-burning heat exchanger that, during operation, combusts a fuel such as natural gas or propane with a heating unit 140.

FIG. 7 shows an exploded view of the heat exchanger assembly 122. The heat exchanger assembly 122 comprises a heat exchanger plate 126, to which a first set of tubes 128 and a second set of tubes 130 are coupled. By way of example, the first set of tubes 128 includes four U-shaped tubes 129, and the second set of tubes 130 includes three U-shaped tubes 131. In the exemplary embodiment, the second set of tubes 130 is shorter than the first set of tubes 128 and is disposed inboard relative to the first set of tubes 128. This nested arrangement allows for a more compact design and creates a primary and secondary path for the combustion gases, which is typical for a multi-pass heat exchanger designed to maximize heat extraction before the gases are vented. The coupling of the first set of tubes 128 and the second set of tubes 130 with the heat exchanger plate 126 may be accomplished by securing the ends of the tubes within corresponding openings in the plate, for example, through a press-fit, brazing, or welding process to ensure a gas-tight seal.

To define the flow path for the combustion gases, the heat exchanger plate 126 comprises a plurality of openings, namely: inlet openings 132, outlet openings 134, intermediate inlet openings 136, and intermediate outlet openings 138. The first set of tubes 128 connects the inlet openings 132 to the intermediate outlet openings 138, while the second set of tubes 130 connects the intermediate inlet openings 136 to the outlet openings 134. The inlet openings 132 are in fluid communication with the heating unit 140, whereby hot products of combustion enter the first set of tubes 128. The final outlet openings 134 are in fluid communication with a draft inducer 142. It should be noted that the arrangement creates a multi-pass flow path where combustion gases travel first through the primary tubes, then through a turnaround chamber 146, and finally through the secondary tubes before exiting. The draft inducer 142 is configured to draw the flue gases from the second set of tubes 130 and forcefully discharge them to an exterior draft inducer vent 144 of the housing 102 (see FIG. 10).

The heat exchanger assembly 122 further comprises a heat shield 148 mounted on the heat exchanger plate 126. Said heat shield 148 is configured as a side wall and, in combination with the heat exchanger plate 126, defines the turnaround chamber 146 that directs combustion gases from the first set of tubes 128 to the second set of tubes 130. The assembly further comprises a first gasket 150 mounted between the heat shield 148 and the heat exchanger plate 126, which is configured to thermally insulate the heat shield 148 from the heat exchanger plate 126. The first gasket 150 is in direct contact with the heat shield 148 on one side and with the heat exchanger plate 126 on the opposite side. The first gasket 150 may be made of a fiberglass material. In an exemplary embodiment, the first gasket 150 has a general ‘A’ shape, a design advantageously configured to maximize surface area coverage on the heat exchanger plate 126 for optimal thermal insulation. The portion of the first gasket 150 situated directly beneath the heat shield 148 forms a rectangular frame, creating a continuous thermal break between the heat shield 148 and the heat exchanger plate 126. Advantageously, due to its overall A-shape, the first gasket 150 substantially surrounds the intermediate inlet openings 136 and the intermediate outlet openings 138, while also partially enclosing the primary inlet openings 132 and outlet openings 134, for instance, by bordering them on three sides.

The heat exchanger assembly 122 further comprises an inducer pan 152. The inducer pan 152, which may have a generally rectangular or pan-like shape, is mounted to the heat exchanger plate 126. The inducer pan 152 includes an inducer mounting section 154 that is adapted for connection with the draft inducer 142. In an exemplary embodiment, the inducer mounting section 154 includes four fastener receptacles 155, such as threaded openings, configured to accept screws or bolts for securing the draft inducer 142 to the inducer pan 152 and a single central opening 157 guiding the air from the outlets 134 to the draft inducer 142. The inducer pan 152 is mounted to the heat exchanger plate 126 in such a manner that it encloses the outlet openings 134. This configuration allows the inducer pan to function as a collector box, capturing the exiting flue gases and directing them through a single inducer pan outlet 154 and into the draft inducer 142.

The heat exchanger assembly 122 further comprises a second gasket 156 mounted between the heat exchanger plate 126 and the inducer pan 152, wherein the second gasket 156 itself comprises a first drainage channel 158. The second gasket 156 is in direct contact with the inducer pan 152 and the heat exchanger plate 126. In this arrangement, the second gasket 156 is sealingly interposed between a surface of the heat exchanger plate 126 and an opposing surface of the inducer pan 152. The first drainage channel 158 is configured to collect and guide liquid condensate away from this sealed interface, preventing moisture from becoming trapped. The second gasket 156 comprises an elastomeric material, such as, for example, a high-temperature silicone, selected for its durability and sealing properties in a heated environment. Advantageously, the second gasket 156 is structurally configured with a sloped inner surface 160. This sloped surface uses gravity to proactively channel any liquid condensate that forms on the gasket toward the first drainage channel 158. The first drainage channel 158 may be configured as a cutout 162 in the second gasket 156. This cutout 162 creates a void in the gasket material, allowing condensate to pass freely through the plane of the gasket instead of being trapped between the sealed surfaces.

The heat exchanger assembly 122 further comprises a thermal insulator assembly 164, which is disposed between the control unit 124 and the heat exchanger plate 126 and defines a substantially enclosed air gap. The thermal insulator assembly 164 is particularly configured to shield the control unit 124 from radiant and convective heat emanating from the area of the heat shield 148. To this end, the thermal insulator assembly 164 comprises, in an exemplary embodiment, a cover pan 166. The cover pan 166, which may have a stamped, pan-like form, is secured to the heat exchanger plate 126, for example, by a screw connection. The cover pan 166 is arranged so as to substantially and completely cover the heat shield 148. Both the heat shield 148 and the cover pan 166 may be formed from a metallic material. A thermal insulating gasket 168, which may be made from a fiberglass material, is disposed between the cover pan 166 and the heat shield 148. In a specific embodiment, the cover pan 166, the insulating gasket 168, the heat shield 148, and the first gasket 150 are all fastened together as a layered assembly to the heat exchanger plate 126. By completely covering the heat shield 148, a sealed air gap is created between the heat shield 148 and the cover pan 166. This trapped layer of stationary air acts as an effective thermal insulator, significantly reducing heat transfer from the hot heat shield to the cooler cover pan, and thereby protecting the nearby control unit 124.

The heat exchanger assembly 122 further comprises an insulation vestibule 170. The insulation vestibule 170 is exemplarily formed from a fiberglass material and may be of a one-piece construction, which simplifies handling and installation during assembly. The insulation vestibule 170 includes three cutouts 172. In the assembled state, the cover pan 166, the inducer pan 152, and the heating unit 140 are each disposed separately within one of the corresponding cutouts 172. This design ensures a close, custom fit around the major components protruding from the heat exchanger plate. Advantageously, the insulation vestibule 170 is configured to substantially and completely cover the remaining exposed surface of the heat exchanger plate 126, acting as a comprehensive insulating blanket. This improves the overall thermal insulation of the assembly and also prevents condensation from forming on the side areas of the heat exchanger plate.

The heat exchanger assembly 122 further includes a third gasket 174, which is configured to provide both thermal insulation and sealing functions. The third gasket 174 is exemplarily of a one-piece construction and formed from a fiberglass material, although a multi-part construction and other suitable materials are also contemplated. In a particular embodiment, the third gasket 174 is configured with a first, closed section 176 and a second, open section 178. The closed section 176 is substantially rectangular and is solid, having no apertures. In the assembled state, this closed section 176 abuts substantially completely against the cover pan 166 to provide thermal insulation, and also abuts a portion of the insulation vestibule 170 to provide a seal. This solid configuration creates an uninterrupted thermal barrier over the hottest parts of the assembly. The open section 178 is arranged adjacent to the closed section 176 and, in the assembled state, abuts the inducer pan 152 and another portion of the insulation vestibule 170. The open section 178 includes a plurality of fastener apertures 182, for example, four holes, which align with the fastener receptacles 155 of the inducer pan 152 to allow the draft inducer 142 to be connected through the third gasket 174. Furthermore, the open section 178 defines a central aperture 184 that substantially aligns with the inducer pan outlet 152, and is thereby configured to delineate the flow path for flue gases entering the draft inducer 142.

The draft inducer 142 comprises a housing 186, which may be of an exemplary volute or “snail-shell” shape, and a motor 188 to drive an internal impeller. The draft inducer 142 is connected to the inducer pan 152, for example, via a screw connection. The heat exchanger assembly 122 also includes a second drainage channel 190, which is defined by at least one drain hole 192 in the housing 186 of the draft inducer 142. As shown in the bottom view of the draft inducer 142 in FIG. 7, the drain hole 192 is exemplarily positioned at what becomes the lowest point of the housing 186 in its mounted orientation. Advantageously, this placement ensures that any liquid condensate collecting within the volute will naturally flow via gravity toward the drain hole 192 for efficient and complete evacuation. Immediately below the draft inducer 142, the heat exchanger assembly 122 comprises a dip pan 194. The dip pan 194 is disposed between the draft inducer 142 and the heating unit 140. Its primary function is to catch the condensate dripping from the drain hole 192 and safely guide it past the heating unit 140, thereby preventing moisture from dripping onto and damaging the burners or other sensitive components of the heating unit.

FIG. 8 shows a perspective partial view of the heat exchanger assembly 122 in an intermediate stage of assembly, wherein the first gasket 150, the second gasket 156, and the heat shield 148 are shown attached to the heat exchanger plate 126. This view clearly illustrates how the first gasket 150, with its characteristic ‘A’ shape, is positioned to cover a substantial surface area of the heat exchanger plate 126. The heat shield 148 is mounted atop the frame portion of the first gasket 150, thereby defining the turnaround chamber 146 while being thermally insulated from the plate 126. The second gasket 156 is also shown mounted in its operational position, ready to form a seal with the inducer pan (not shown in this view). The integrated first drainage channel 158 is clearly visible as a cutout 162 within the body of the second gasket 156.

FIG. 9 shows a partial frontal view of the heat exchanger assembly 122 with a mounted heating unit 140. This view illustrates the effectiveness of the dual-drainage system, wherein the combination of the first drainage channel 158 and the second drainage channel 190 provides for particularly effective and comprehensive drainage of condensate. Condensate collected by the first drainage channel 158, which is located within the second gasket 156, is guided such that it can drain downward in the space between the heat exchanger plate 126 and the heating unit 140. Separately, condensate evacuated from the draft inducer housing via the second drainage channel 190 is caught by the drip pan 194. The drip pan 194 then guides this second stream of condensate laterally past the side of the heating unit 140, where it can drain away. As a result of this design, the two drainage paths are non-coplanar, and their initial vectors away from the assembly are oriented substantially perpendicular to one another. This spatial separation ensures that the two condensate streams are managed independently and do not interfere with each other, providing a highly reliable system for protecting the heating unit 140 from moisture damage from multiple sources.

FIG. 10 shows a top plan view of the heat exchanger assembly 122 and the control unit 124. The control unit 124 is disposed within a control unit compartment 196, which is bounded by a plurality of control unit panels 198, 200, and 202. On the side of the control unit compartment 196 facing the heat exchanger assembly 122, and in particular the heat exchanger plate 126, a first control unit panel 198 is arranged substantially parallel to the heat exchanger plate 126. A second control unit panel 200 extends laterally, substantially perpendicular to the first control unit panel 198. In particular, this second panel 200 is spaced apart from an outer wall 103 of the main housing 102 of the HVAC unit 100. In this region, the housing 102 defines an inlet 204, which allows outside ambient air to enter the housing 102, specifically into the space that forms an air inlet duct 210 leading past the control unit 124. Additionally, below the inlet 204, the draft inducer vent 144 is arranged, through which the combustion exhaust gases exit the main housing 102. On a side opposite the second control unit panel 200, a third control unit panel 202 is arranged, extending, for example, obliquely relative to the first and second control unit panels 198, 200. In an exemplary embodiment, a printed circuit board (PCB) 208 of the control unit 124 is mounted to this third control unit panel 202. The electronic circuitry of the control unit 124 is arranged on this PCB 208 and is connected to various other components of the HVAC unit 100 via a plurality of connectors 211.

To ensure sufficient cooling of the control unit 124 during operation, the air entering through the inlet 204 is guided along the defined air inlet duct 210. This path directs cool, ambient air past the control unit panels 198, 200, and 202 before the air is drawn towards the heating unit 140. The air inlet duct 210 comprises a first section 212, a second section 214, and a third section 216, which together create a flow path around the control compartment. The first section 212 is defined by the space between the second control unit panel 200 and the main housing 102 of the HVAC unit. The second section 214 is defined by the space between the first control unit panel 198 and the third gasket 174. Subsequently, the third section 216 is defined by the space between the third control unit panel 202 and the third gasket 174. This path ensures that the cooling air makes intimate contact with multiple surfaces bounding the control unit compartment, maximizing convective heat transfer away from the sensitive electronics mounted on the PCB 208.

To minimize the thermal influence of the hot heat exchanger assembly 122 on the air flowing through the second section 214 of the air inlet duct 210, the assembly features a two-stage thermal insulating system 218 in this region (see FIG. 11). This thermal insulating system 218 first comprises the third gasket 174, which, as previously described, also defines one side of the air inlet duct 210. The thermal insulating system 218 further comprises an elastomeric spacer 220 (see FIG. 10). This spacer 220 has a first surface that abuts the second control unit panel 200 and an opposing second surface that abuts the third gasket 174. The elastomeric spacer 220 is configured to be under some compression in its installed state, thereby actively biasing the third gasket 174 toward the thermal insulator assembly 164. This biasing action ensures a continuous, reliable seal between the gasket and the assembly, preventing hot air from leaking into the cooling duct. On this side, the third gasket 174 abuts directly against the thermal insulator assembly 164 (comprising the cover pan 166 and its internal air gap), which forms the second stage of the thermal insulating system 218. This two-stage system is highly effective, as the thermal insulator assembly 164 significantly reduces radiant and convective heat transfer, while the third gasket 174 and elastomeric spacer 220 provide a further thermal break and maintain the structural integrity of the cool air duct.

While only certain features and embodiments have been illustrated and described, many modifications and changes may occur to those skilled in the art (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure. Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described (i.e., those unrelated to the presently contemplated best mode of carrying out the disclosure, or those unrelated to enabling the claimed disclosure). It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.

Claims

1. Heat exchanger assembly, comprising:

a heat exchanger plate;

a first set of tubes and a second set of tubes coupled to the heat exchanger plate;

an inducer pan mounted to the heat exchanger plate, said inducer pan having a draft inducer mounting section;

a draft inducer having a housing, said housing mounted to the inducer pan;

a first drainage channel disposed between the housing of the draft inducer and the heat exchanger plate; and

a second drainage channel at least partially located in the housing of the draft inducer.

2. The heat exchanger assembly according to claim 1, further comprising a heat shield mounted on the heat exchanger plate, said heat shield configured as a side wall and in combination with the heat exchanger plate defining a turnaround chamber that directs gases from the first set of tubes to the second set of tubes and a first gasket mounted between the heat shield and the heat exchanger plate, configured to thermally insulate the heat shield from the heat exchanger plate.

3. The heat exchanger assembly according to claim 2, wherein the first gasket comprises a fiberglass material.

4. The heat exchanger assembly according to claim 1, comprising a second gasket mounted between the heat exchanger plate and the inducer pan, wherein the second gasket comprises the first drainage channel.

5. The heat exchanger assembly according to claim 4, wherein the second gasket comprises an elastomeric material.

6. The heat exchanger assembly according to claim 1, wherein the second drainage channel is defined by at least one drain hole in the housing of the draft inducer.

7. The heat exchanger assembly according to claim 6, comprising a dip pan disposed between the draft inducer and a heating unit, wherein the dip pan guides the condensate from the drain hole in the housing of the draft inducer past the heating unit.

8. The heat exchanger assembly according to claim 1,

wherein the heat exchanger plate comprises at least one inlet opening, at least one outlet opening, at least one intermediate inlet opening and at least one intermediate outlet opening, wherein the first set of tubes are connected to the inlet openings and the intermediate outlet openings and the second set of tubes are connected to the intermediate inlet opening and the outlet openings.

9. The heat exchanger assembly according to claim 1, further comprising:

a heating unit mounted to the heat exchanger plate;

a control unit configured to control at least one of the draft inducer and the heating unit, said control unit being mounted to a panel;

an air inlet duct configured to guide ambient air past the control unit to the heating unit, wherein the air inlet duct is partially defined by the panel;

a thermal insulator assembly defining a substantially enclosed air gap and disposed between the control unit and the heat exchanger plate; and

a third gasket in contact with the thermal insulator assembly and partially defining the air inlet duct.

10. A heating, ventilation and air conditioning (HVAC) system with a heat exchange assembly according to claim 1.

11. Heat exchanger assembly, comprising:

a heat exchanger plate;

a first set of tubes and a second set of tubes coupled to the heat exchanger plate;

a heat shield mounted on the heat exchanger plate, said heat shield configured as a side wall and in combination with the heat exchanger plate defining a turnaround chamber that directs gases from the first set of tubes to the second set of tubes;

an inducer pan mounted to the heat exchanger plate, said inducer pan comprising a draft inducer mounting section; and

a second gasket disposed between the heat exchanger plate and the inducer pan, wherein the second gasket comprises an elastomeric material.

12. The heat exchanger assembly according to claim 11, wherein the second gasket comprises a drainage channel.

13. The heat exchanger assembly according to claim 12, wherein the second gasket is structurally configured with a sloped inner surface to channel liquid condensate toward the drainage channel.

14. The heat exchanger assembly according to claim 11, wherein the elastomeric material is a high temperature silicone.

15. The heat exchanger assembly according to claim 11, comprising a draft inducer having a housing, said housing mounted to the inducer pan and a second drainage channel at least partially located in the housing of the draft inducer.

16. Heat exchanger assembly, comprising:

a heat exchanger plate;

a draft inducer mounted to the heat exchanger plate;

a heating unit mounted to the heat exchanger plate;

a control unit configured to control at least one of the draft inducer and the heating unit, said control unit being mounted to a panel;

an air inlet duct configured to guide ambient air past the control unit to the heating unit, wherein the air inlet duct is partially defined by the panel;

a thermal insulator assembly defining a substantially enclosed air gap and disposed between the control unit and the heat exchanger plate; and

a third gasket in contact with the thermal insulator assembly and partially defining the air inlet duct.

17. The heat exchanger assembly according to claim 16, further comprising an elastomeric spacer having a first surface abutting the panel and a second surface abutting the third gasket, wherein the elastomeric spacer is configured to bias the third gasket toward the thermal insulator assembly.

18. The heat exchanger assembly according to claim 16, wherein the thermal insulator assembly comprises a heat shield configured as a side wall of a turnaround chamber that directs gases of the heat exchanger assembly and a cover pan, mounted indirectly to the heat shield with a thermal insulating gasket.

19. The heat exchanger assembly according to claim 16, further comprising an inducer pan mounted to the heat exchanger plate, said inducer pan having a draft inducer mounting section and a second gasket mounted between the heat exchanger plate and the inducer pan, wherein the second gasket comprises a first drainage channel.

20. The heat exchanger assembly according to claim 19, further comprising a second drainage channel at least partially located in the housing of the draft inducer.