WATER-CONTROL SUPPORT ASSEMBLY FOR AIR HANDLING UNIT

Abstract

The invention provides an outdoor rooftop HVAC assembly comprising: (i) a roof curb or an equipment rail, and (ii) an air handling unit. The roof curb and equipment rail each have bottom and top ends. The bottom end is mounted on a roof deck of a building. The air handling unit is mounted on the top end. When provided, the roof curb includes a housing that surrounds an HVAC passage extending from the building, through the roof deck, and to the air handling unit. The air handling unit includes an outdoor heat exchanger. When provided, the equipment rail includes a housing to which a gutter assembly is integral. The gutter assembly includes a water trough alongside the housing. The water trough is upwardly open and located below the outdoor heat exchanger to receive water that melts from the outdoor heat exchanger.

Description

TECHNICAL FIELD

The present disclosure relates generally to support assemblies for HVAC air handling units.

BACKGROUND

In the HVAC industry, commercial air handling units, sometimes located on rooftops, can be used to regulate the interior temperatures of the buildings they service. Historically, these units have heated air using natural gas. When natural gas combusts, CO₂ is produced. The industry has therefore been shifting to air-source heat pumps in an effort to decarbonize HVAC systems. Some advanced air-source heat pumps can operate in very low, below-freezing ambient outdoor temperatures.

When air-source heat pumps operate, water from the air can condense on the outdoor heat exchanger. And when temperatures drop heat below freezing, ice can therefore build up on the outdoor heat exchanger. This ice build-up can negatively impact the performance of the heat pump. To address this problem, air-source heat pumps commonly are adapted to undergo defrost cycles. Such defrost cycles, however, can melt a substantial amount of ice, thereby generating significant water run-off.

It would be desirable to provide support structures for air handling units, where the support structures are configured to manage water run-off from the defrost cycle of an outdoor heat exchanger of an air-source heat pump. It would be desirable to provide the support structures in forms that can be readily used with different air handling unit sizes, models, and configurations. In addition, it would be desirable to provide at least some embodiments where the support structures can enhance water management without unduly expanding the footprint of the structures and/or are configured to protect certain water-management features of the system.

SUMMARY

In certain embodiments, the invention provides an outdoor rooftop HVAC curb assembly comprising a roof curb and an air handling unit. The roof curb has a bottom end and a top end. The bottom end of the roof curb is mounted on a roof deck of a building. The air handling unit is mounted on the top end of the roof curb. The roof curb comprises a housing (e.g., a metal housing) that surrounds an HVAC passage extending from inside the building, through the roof deck, and to the air handling unit. The air handling unit includes an outdoor heat exchanger. The roof curb includes a gutter assembly that is integral to the housing of the roof curb. The gutter assembly includes a water trough alongside the housing of the roof curb. The water trough is upwardly open and located below a bottom region of the outdoor heat exchanger so as to be configured to receive water that melts from the outdoor heat exchanger during a defrost cycle thereof.

Some embodiments of the invention provide an outdoor rooftop HVAC equipment rail assembly comprising a plurality of equipment rails and an air handling unit. Each of the equipment rails has a bottom end and a top end. The bottom ends of the equipment rails are mounted on a roof deck of a building. The air handling unit is mounted on the top ends of the equipment rails. Each of the equipment rails comprises a housing (e.g., a metal housing) that surrounds an interior rail region. The air handling unit includes an outdoor heat exchanger. At least one of the equipment rails is a drainage rail that includes a gutter assembly integral to the housing of the drainage rail. The gutter assembly includes a water trough surrounded by the housing of the drainage rail. The water trough is upwardly open and located below a bottom region of the outdoor heat exchanger so as to be configured to receive water that melts from the outdoor heat exchanger during a defrost cycle thereof.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent to skilled artisans given the present descriptions, drawings, and claims.

BRIEF DESCRIPTION OF DRAWINGS

The following drawings are illustrative of particular examples of the present invention and therefore do not limit the scope of invention. The drawings are not necessarily to scale, though embodiments can include the scale illustrated, and are intended for use in conjunction with the explanations in the following detailed description wherein like reference characters denote like elements. Examples of the present invention will hereinafter be described in conjunction with the appended drawings.

FIG. 1 is a schematic cross-sectional side view of an outdoor rooftop HVAC curb assembly comprising a gutter assembly that is integral to a housing of a roof curb in accordance with one embodiment of the present invention.

FIG. 2 is a schematic cross-sectional side view of an outdoor rooftop HVAC curb assembly comprising a gutter assembly that is integral to a housing of a roof curb in accordance with another embodiment of the invention.

FIG. 3 is a schematic cross-sectional side view of an outdoor rooftop HVAC equipment rail assembly comprising a gutter assembly that is integral to a housing of an equipment rail in accordance with still another embodiment of the invention.

FIG. 4 is a schematic cross-sectional side view of an outdoor rooftop HVAC equipment rail assembly comprising a gutter assembly that is integral to a housing of an equipment rail in accordance with yet another embodiment of the invention.

FIG. 5 is a schematic cross-sectional side view of an outdoor rooftop HVAC equipment rail assembly comprising a gutter assembly that is integral to a housing of an equipment rail in accordance with still another embodiment of the invention.

FIG. 6 is a schematic cross-sectional side view of an outdoor rooftop HVAC equipment rail assembly comprising a gutter assembly that is integral to a housing of an equipment rail in accordance with yet another embodiment of the invention.

DETAILED DESCRIPTION

The invention provides an outdoor rooftop HVAC support assembly, such as an outdoor rooftop HVAC curb assembly or an outdoor rooftop HVAC equipment rail assembly. Certain implementations include an HVAC support assembly comprising a roof curb or an equipment rail having a gutter system configured to receive water with a water trough integral to the roof curb or equipment rail. The assembly can thus be referred to as a water-control roof curb assembly or a water-control equipment rail assembly. Moreover, either assembly type can be referred to as a water-control support assembly.

The support assemblies described herein may include any of a variety of commercially available air handling units. The air handling units mentioned below are merely examples; the following list is nonlimiting. One suitable example is a Daikin Rebel® air-source heat pump unit, which is commercially available from Daikin America, Inc. (Orangeburg, New York, U.S.A.). Other suitable examples include the AAON RN or RQ Series rooftop units, which are commercially available from AAON, Inc. (Tulsa, Oklahoma, U.S.A.). The invention is not limited to using any particular air handling unit. Rather, various types of air handling units can be used.

Thus, the present support assembly can be either a roof curb assembly or an equipment rail assembly. When provided, the curb assembly includes a housing (e.g., defining a pedestal) on which an air handling unit is mounted. Similarly, when the equipment rail assembly is provided, it includes a housing (e.g., defining a railing) on which an air handling unit is mounted. In many embodiments, the air handling unit includes an outdoor heat exchanger. When provided, the outdoor heat exchanger preferably is integrated into, defines, and/or is part of an exterior wall (or face) of the air handling unit. This is shown in the nonlimiting examples of FIGS. 1-6.

Roof Curb Assemblies

FIG. 1 is a schematic cross-sectional side view of an exemplary embodiment of an outdoor rooftop HVAC curb assembly 10. The assembly 10 includes a roof curb 12. The assembly 10 also includes an air handling unit 14. The air handling unit 14 includes an outdoor heat exchanger 16. Furthermore, the air handling unit 14 preferably includes a fan 48 positioned to move air through the outdoor heat exchanger 16. In some embodiments, the air handling unit includes a plurality of outdoor heat exchangers.

The roof curb 12 has a bottom end 18 and a top end 20. The bottom end 18 of the roof curb 12 is mounted on a roof deck 22 of a building 250. The roof curb 12 includes a housing 28 that surrounds an HVAC passage 90 extending from inside the building 250, through the roof deck 22, and to the air handling unit 14. The housing 28 of the roof curb 12 preferably comprises (e.g., is formed of) metal, such as sheet metal. In some embodiments, the metal is steel (e.g., galvanized steel) or aluminum. In alternate embodiments, the housing 28 of the roof curb 12 comprises (e.g., is formed of) polymer, a composite, or wood.

The air handling unit 14 is mounted on the top end 20 of the roof curb 12. In some embodiments, the top end 20 of the roof curb 12 includes a wood header 24. When provided, the wood header can be formed of any wood cut to the appropriate dimensions for configuration as a header of the desired roof curb. In some examples, the housing of the roof curb has four sides (e.g., four walls), and for each side of the roof curb, the wood header comprises a wood board having substantially the same length as the roof curb. Thus, some embodiments include a wood header comprising four wood boards, each located at the top end of the roof curb.

The roof curb can be customized with various structural features. As noted above, in some embodiments, the housing 28 of the roof curb 12 comprises four walls that collectively delineate a rectangular shape. These walls preferably comprise metal (e.g., steel or aluminum), although polymer, composite, or wood may alternatively be used. If desired, a single metal sheet can be formed (e.g., bent) so as to define all four walls. In other cases, four separate metal sheets respectively define four walls of the housing 28. In still other cases, two metal sheets are used, with each sheet being formed (e.g., bent) so as to define two of the four walls. Thus, in various embodiments, the housing consists (or consists essentially) of one or more metal sheets. Preferably, the walls comprise (e.g., are formed of) steel or aluminum. When steel is used, it can optionally be galvanized steel. Furthermore, the top end of the roof curb can optionally include four wood header boards, which extend respectively along top regions of the four metals walls of the housing.

Thus, in some embodiments, the housing 28 of the roof curb 12 includes four metal walls that collectively delineate a rectangular shape. In embodiments of this nature, the bottom end 18 of the roof curb 12 can optionally include four metal flanges 26 that project outwardly respectively from the four metal walls of the housing 28. In such cases, the bottom end 18 of the roof curb 12 can be mounted on the roof deck 22 of the building 250 such that the four metal flanges 26 are layered over the roof deck 22, e.g., with at least one additional sealing layer (or other gasket) layered over each of the four metal flanges. When provided, the additional layer(s) can be any of various sealing layers or gaskets conventionally used for sealing curbs to the roofs of buildings.

When provided, the flanges 26 can be provided in various configurations. In some cases, they are all connected and/or they can simply be four regions of a single base plate that is outwardly turned and extends about the perimeter of the bottom end of the roof curb. If desired, one or more of the flanges 26 or a base plate can include a fastener opening. In such cases, a fastener can be received in each fastener opening, thereby fastening the roof curb to the roof deck. When provided, the fasteners can be screws, rivets, or other mechanical fasteners. It is to be appreciated, however, that such fastener openings and fasteners are optional.

Some embodiments of the roof curb assembly include a roof membrane. Preferably, a roof membrane lays over the roof deck. In addition, the roof membrane can optionally have an upright portion extending upwardly and alongside the housing 28 of the roof curb 12. In some embodiments of this nature, an upright portion of the roof membrane is anchored to a wood header at the top end of the roof curb.

Preferably, the HVAC curb assembly 10 includes a supply duct 40 and a return duct 38. In more detail, the supply duct 40 and the return duct 38 can both be disposed in the HVAC passage 90 and surrounded by the housing 28 of the roof curb 12. One nonlimiting example is shown in FIG. 1.

In some embodiments, the air handling unit 14 has a bottom base 30, optionally with a downwardly directed flange 32 that extends along a perimeter of the bottom base 30. In such cases, the air handling unit 14 can be mounted on the top end 20 of the roof curb 12 such that the bottom base 30 of the air handling unit 14 rests on the top end 20 of the roof curb 12, in some cases with an optional downwardly directed flange 32 at least partially surrounding the top end 20 of the roof curb 12. In certain embodiments of this nature, the downwardly directed flange 32 is located further from the HVAC passage 90 than is at least part of the gutter assembly 34. Reference is made to the nonlimiting example of FIG. 1.

As noted above, the air handling unit 14 preferably includes a fan 48 configured to move outdoor air over the outdoor heat exchanger 16. In such cases, at least part of the gutter assembly 34 can optionally be in vertical alignment with (e.g., aligned directly below) the fan 48. Moreover, in embodiments of this nature, at least part of the gutter assembly 34 (e.g., at least part of a trough 36 thereof) can optionally be in vertical alignment with both the outdoor heat exchanger 16 and the fan 48. This is the case, for example, in FIG. 1.

Thus, the roof curb 12 includes a gutter assembly 34. The gutter assembly 34 is integral to the housing 28 of the roof curb 12. The gutter assembly 34 includes a water trough 36 alongside the housing 28 of the roof curb 12. The water trough 36 is upwardly open and located below (e.g., in direct vertical alignment with) a bottom region of the outdoor heat exchanger 16 so as to be configured to receive water that melts from the outdoor heat exchanger 16 during a defrost cycle thereof.

The gutter assembly 34 can be provided in various configurations. Preferably, an entirety of the gutter assembly 34 is located at an elevation lower than an entirety of the outdoor heat exchanger 16. In some embodiments, an upright portion of the roof membrane is at an elevation where the gutter assembly 34 is also located. Additionally or alternatively, the water trough 36 of the gutter assembly 34 can be located at an elevation where the supply duct 40 and the return duct 38 are also located. This is shown in FIG. 1. In some embodiments, the gutter assembly 34 is anchored to a wood header 24 at the top end 20 of the roof curb 12. The gutter assembly can be supported by the roof curb in various ways.

In some embodiments, an entirety of the gutter assembly (or at least the water trough thereof) is located vertically below (e.g., so as to be in direct vertical alignment with) an outdoor heat exchanger 16 and/or other parts of the air handling unit 14. In arrangements of this nature, the outdoor heat exchanger and/or other parts of the air handling unit overhang the water trough. This may be advantageous in terms of providing protection against hail and other airborne items (e.g., debris) striking the gutter system and/or entering the water trough. It is to be appreciated, however, that other embodiments of the invention involve a vertical outdoor heat exchanger that does not provide the same type of vertical shielding.

Further, the gutter assembly (or at least a trough thereof) can optionally be located internally of at least one protective wall. The protective wall may be a wall of the housing of the roof curb, as shown in FIG. 2, or it may be a wall of the gutter assembly that is spaced outwardly from the wall of the housing, as shown in FIG. 1. In such cases, the protective wall can provide some protection to the gutter assembly (or at least a water trough thereof) on at least one side. In some cases, the protective wall surrounds the gutter assembly (or at least a water trough thereof). Moreover, some embodiments provide a lateral shielding arrangement in combination with the above-noted type of vertical shielding arrangement. Two examples are shown in FIGS. 1 and 2.

The gutter assembly 34 can be configured to direct water flow. In some embodiments, the gutter assembly 34 includes a water drain line 42 in fluid communication with the water trough 36 of the gutter assembly 34. Preferably, the water drain line 42 passes through an opening (optionally an opening separate from the passage 90) in the roof deck 22 of the building 250, such that the water drain line 42 is configured to deliver water from the trough 36 of the gutter assembly 34 into the building 250. If desired, the water drain line can pass through the passage 90. In other cases, the water drain line may be configured to deliver water to a roof drain.

In some embodiments, the water trough 36 of the gutter assembly 34 is located alongside an upper portion of the housing 28 of the roof curb 12. Additionally or alternatively, the water drain line 42 of the gutter assembly 34 can be located alongside a lower portion of the housing 28 of the roof curb 52. In some embodiments, the water drain line 42 extends vertically alongside the housing 28 of the roof curb 12.

The water trough 36 can be provided in different configurations. In the embodiment of FIG. 1, the water trough 36 comprises two sloped, converging walls 46. Here, the converging walls 46 of the water trough 36 are configured to direct water flow into the water drain line 42. Instead of these sloped, converging sidewalls 46, the gutter system 34 shown in FIG. 1 can be replaced with a trough that has a single sloped bottom wall, e.g., like the one shown in FIG. 2. Furthermore, if desired, the bottom wall of the trough can simply be horizontal. Another option is to have the bottom wall of the trough be sloped downwardly in a length direction, e.g., so the trough slopes downwardly toward a water drain line located at one end of the length of the trough.

The trough 36 can be configured to follow the course of the outdoor heat exchanger 16. Preferably, the length of the trough 36 is equal to or greater than the length of the outdoor heat exchanger 16.

Furthermore, the gutter assembly 34 can optionally be equipped with a debris screen 44. One example is shown in FIG. 1. When provided, the debris screen 44 can prevent debris, such as leaves, rocks, and other matter, from entering the trough 36 and/or the water drain line 42.

The air handling unit 14 can include a variety of features to heat and cool air. As noted above, the air handling unit 14 preferably includes a fan 48 configured to move outdoor air over an outdoor heat exchanger 16. Additionally or alternatively, the air handling unit 14 can be in fluid communication with both a return duct 38 and a supply duct 40. For example, the air handling unit 14 can have a bottom side attached to both the return duct 38 and the supply duct 40.

In certain embodiments, the air handling unit is a gas-heat rooftop unit, such as a high turndown gas heat rooftop unit, which is configured to create water from combustion (e.g., at low turn-down rates) during ambient outdoor temperatures below 32 degrees fahrenheit. In such cases, the water trough preferably is configured to receive the water produced from the combustion.

In some cases, the air handling unit 14 further includes an evaporator heat exchanger configured to cool air that flows from the return duct, into the air handling unit, over the evaporator heat exchanger (which is located within the air handling unit), out of the air handling unit, and into the supply duct. In some embodiments of this nature, the air handling unit further includes a drip pan located directly under the evaporator heat exchanger to catch water that condenses on the evaporator heat exchanger and drips downwardly when the evaporator heat exchanger cools humid air. Such a drip pan can be separate from (e.g., spaced apart from and/or not in fluid communication with) the gutter assembly.

Preferably, the outdoor heat exchanger 16 is a component of an air-source heat pump, such that the outdoor heat exchanger is configured to selectively serve as either an evaporator heat exchanger or a condenser heat exchanger.

FIG. 2 shows another configuration of the outdoor rooftop HVAC curb assembly 50. Here again, the assembly 50 includes a roof curb 52 and an air handling unit 54. The air handling unit 54 includes an outdoor heat exchanger 20. The roof curb 52 has a top end 56 and a bottom end 58. The bottom end 58 of the roof curb 52 is mounted on the roof deck 72 of a building 250, and the air handling until 54 is mounted on the top end 56 of the roof curb 52. The top end 56 of the roof curb 52 can optionally include a wood header 60. If desired, the wood header configurations noted above with respect to the embodiment of FIG. 1 can also be used in the embodiment of FIG. 2. The roof curb 52 includes a housing 74 that surrounds an HVAC passage 90 extending from inside the building 250, through the roof deck 72, and to the air handling unit 54. The roof curb 52 includes a gutter assembly 62. The gutter assembly 62 is integral to the housing 74 of the roof curb 52.

The features described previously with respect to the embodiment of FIG. 1 can also be provided in the embodiment of FIG. 2. Thus, some of the same features described above relative to FIG. 1 are also shown in FIG. 2.

The gutter assembly 62 can be provided in different configurations. In some embodiments, a water trough 64 of the gutter assembly 62 is located alongside an upper portion of the housing 74 of the roof curb 52. For example, the water trough 64 (or at least part thereof) can optionally be located at or adjacent the top end 56 of the roof curb 52, while preferably not being located above (i.e., at a higher elevation than) the top end of the roof curb (or at least an entirety of the water trough preferably is not located above the top end of the roof curb). As exemplified in FIGS. 1 and 2, this can optionally be the case for any embodiment of the roof curb assembly.

In FIG. 2, the illustrated gutter assembly 62 is inside of the housing 74 of the roof curb 52. In such cases, the housing 74 of the roof curb 52 provides lateral protection of the gutter assembly 62. Preferably, the housing 74 surrounds (e.g., entirely about 360 degrees) the gutter assembly 62. In addition, the embodiment shown in FIG. 2 provides a vertical shielding arrangement, as discussed previously. It is to be appreciated, however, that the outdoor heat exchanger in FIG. 2 can alternatively be provided in a vertical orientation.

With continued reference to FIG. 2, the housing 74 of the roof curb 52 itself bounds one side (i.e., an outer side) of the water trough 64. In other cases, a separate trough outer sidewall is mounted alongside an interior of the housing of the roof curb. If desired, the water trough can be supported alongside an interior (or alongside an exterior) of the housing by virtue of one or more latches, hooks, or flanges that extend from the water trough and are fitted over the top end of the roof curb. This can optionally be the case for any roof curb embodiment of the present disclosure. Thus, the water trough may be hung from the roof curb. If desired, latches, hooks, or flanges of this nature can be anchored (e.g., by one or more fasteners) to a wood header at the top of the roof curb. Various other manners of integrating a gutter assembly into the housing of a roof curb will be apparent to a person of ordinary skill in the art, given the present teaching as a guide.

The gutter assembly 62 can optionally include a water drain line 70, which preferably is located (at least in part) alongside a lower portion of the housing 74 of the roof curb 52. When provided, the water drain line 70 can optionally extend vertically alongside the housing 74 of the roof curb 52. In the embodiment of FIG. 2, the water drain line 70 passes through an opening (optionally through passage 90) in the roof deck 72 of the building 250, such that the water drain line 70 is configured to deliver water from the trough 64 of the gutter assembly 62 into the building 250. In other cases, the water drain line is configured to deliver water to a roof drain.

Preferably, the trough 64 of the gutter assembly 62 is equipped with one or more heating elements 68. This can optionally be the case for any embodiment of the present disclosure. When provided, the one or more heating elements 68 are configured to prevent water from freezing in the trough 64 and/or to melt any ice that may form therein. This can prevent ice from building up and facilitate water flow into the water drain line 70.

The roof curb 52 can include a variety of features. In some cases, the roof curb includes an internal frame structure. When provided, the internal frame structure can divide the HVAC passage 90 into a plurality of rectangular openings. In some cases, an internal frame structure of the roof curb includes one or more duct rails that extend across the HVAC passage 90.

Some embodiments provide a configuration of the gutter assembly wherein the gutter assembly is provided on two sides of the roof curb. This can be the case for other embodiments of the roof curb assembly. In some cases, a trough of the gutter assembly is elongated so as to extend along at least two sides of the air handling unit. In other cases, a first trough of the gutter assembly extends along one side of the air handling unit, and a second trough of the gutter assembly extends along an opposite side of the air handling unit.

Thus, in some cases, a trough of the gutter assembly is elongated so as to extend along at least two sides of the air handling unit. In some embodiments of this nature, the trough includes at least one corner, such that the trough includes: (i) a first length extending along a first side of the air handling unit, and (ii) a second length extending along a second side of the air handling unit. In such cases, the first and second lengths of the trough may extend respectively along axes that are at least substantially perpendicular to each other.

Equipment Rail Assemblies

FIG. 3 is a cross sectional side view of an outdoor rooftop HVAC equipment rail assembly 120. Here, a gutter assembly 140 is integral to a housing 150 of an equipment rail 130. Preferably, the outdoor rooftop HVAC equipment rail assembly 120 includes a plurality of equipment rails 130. The assembly 120 also includes an air handling unit 172.

The equipment rails 130 can have various features. Each equipment rail 130 has a bottom end 124 and a top end 126. The bottom end 124 of each equipment rail 130 is mounted on a roof deck 128 of a building 250. The air handling unit 122 is mounted on the top ends 126 of two or more equipment rails 130 of the assembly 120. Preferably, at least one of the equipment rails 130 comprises a housing 150 that bounds (e.g., surrounds) an interior rail region 160.

At least one of the equipment rails 130 is a drainage rail 136. The gutter assembly 140 (or at least a water trough thereof) preferably is located in the interior rail region 160 of the drainage rail 136. As seen in FIG. 3, the equipment rail 130 on the right is a drainage rail 136. While FIG. 3 shows an assembly wherein only one of the equipment rails 130 is a drainage rail 136, other embodiments involve two equipment rails 130 being drainage rails (see the nonlimiting example of FIG. 4).

In the nonlimiting example of FIG. 3, the assembly 120 includes two equipment rails 130 that are located at (e.g., so as to support) opposite sides of the air handling unit 122. Here, the two equipment rails 130 are spaced apart and preferably are elongated such that the two equipment rails extend respectively along two axes that are at least substantially parallel to each other. Two such equipment rails 130, for example, may be spaced apart by more than 1 foot, more than 3 feet, more than 5 feet, or even more than 6 feet. In embodiments of this nature, there may be only two equipment rails. This, however, need not always be the case. Depending on the particular installation, it may be desirable to provide three or more equipment rails.

Preferably, each equipment rail has an elongated generally rectangular housing configuration (e.g., a rail configuration). The configuration of any equipment rail of the present disclosure can optionally be of this nature. Moreover, each equipment rail can have a length that is at least 3 times, at least 5 times, at least 10 times, or even at least 12 times as great as a width of the equipment rail. Additionally or alternatively, each equipment rail can optionally have a height of at least 6 inches, at least 8 inches, or even at least 10 inches. In some cases, the rail dimensions noted in this paragraph are provided together with the rail spacing noted in the previous paragraph. It will be appreciated that the dimensions and spacing of the equipment rails in a given assembly will vary depending on the particular installation.

While some of the drawings may show slight gaps between the bottom of the air handling unit and the top ends of equipment rails (or the top end of a roof curb), it is to be appreciated that this is merely for illustration purposes. Thus, it will be understood that the air handling unit rests on the top of a roof curb or on the tops of two more equipment rails. Preferably, there is no water tray in between the bottom of the air handling unit and the top of the roof curb or the equipment rails. This is shown in the nonlimiting examples of FIGS. 1-6.

The top end 126 of each equipment rail 130 can include various features. Preferably, the top end 126 of each equipment rail 130 includes a wood header 146, optionally with a sheet metal cap over a top of the wood header. When a wood header 146 is provided, the gutter assembly 140 and/or a roofing membrane and/or other components can optionally be anchored to the wood header 146 at the top end 126 of the drainage rail 136. In the equipment rail assembly embodiments, the wood header can be of the same general nature described above relative to FIGS. 1 and 2. For example, it can optionally comprise four wood boards each extending along one of four sides of the housing. It is to be appreciated, however, that the wood header is not strictly required.

The air handling unit 122 includes an outdoor heat exchanger 132. As noted above, at least one of the equipment rails 130 is a drainage rail 136, which includes a gutter assembly 140 integral to a housing 150 of the drainage rail 136. The gutter assembly 140 includes a water trough 144. In the embodiment of FIG. 3, the water trough 144 is located in the interior rail region 160 of the drainage rail 136. Thus, the illustrated water trough 144 is surrounded by the housing 150 of the drainage rail 136.

In other embodiments, the gutter assembly is integrated onto an exterior side of the housing of the drainage rail (e.g., in the same general manner as shown in FIG. 1 for a roof curb). If desired, a water trough of the gutter assembly can be supported alongside an exterior (or alongside an interior) of the housing by virtue of one or more latches, hooks, or flanges that extend from the water trough and are fitted over the top end of the equipment rail. This can optionally be the case for any equipment rail embodiment of the present disclosure. Thus, the water trough may be hung from an equipment rail. If desired, latches, hooks, or flanges of this nature can be anchored (e.g., by one or more fasteners) to a wood header at the top of the equipment rail. Various other manners of integrating a gutter assembly into the housing of an equipment rail will be apparent to a person of ordinary skill in the art, given the present teaching as a guide.

The water trough 144 can be upwardly open and located below (e.g., in direct vertical alignment with) a bottom region of the outdoor heat exchanger 132 so as to be configured to receive water that melts from the outdoor heat exchanger 132 during a defrost cycle thereof.

In some embodiments, an entirety of the gutter assembly 140 is located at an elevation lower than an entirety of the outdoor heat exchanger 132. Preferably, the length of the water trough 144 of the gutter assembly 140 is equal to or greater than the length of the outdoor heat exchanger 132.

In FIG. 3, the bottom end 124 of each equipment rail 130 includes an outwardly projecting base plate 148. When provided, the base plate 148 can optionally comprise four flanges of the nature described above, in which case the flanges may or may not be connected (or integral) to one another. The bottom end 124 of each equipment rail 130 can be mounted on the roof deck 128 of the building 250, e.g., such that a base plate 148 thereof is layered over the roof deck of the building, optionally with at least one additional sealing layer or gasket layered over the base plate 148.

It is to be appreciated that while various self-flashing equipment rail designs advantageously include a base plate 148, this is not required. If desired, the bottom of one or more equipment rails can have a conventional cant-type base region or a conventional elevated cant-type base region.

In some embodiments, the outdoor rooftop HVAC equipment rail assembly further includes a roof membrane. The roof membrane lays over the roof deck and can optionally have an upright portion extending upwardly and alongside the housing of the drainage rail. In such cases, the upright portion of the roof membrane can optionally be anchored to a wood header at the top end of the drainage rail. When provided, the upright portion of the roof membrane can optionally be at an elevation where the gutter assembly (e.g., a water trough thereof) is also located.

The housing 150 of each equipment rail 130 can be provided in various configurations. Preferably, the housing 150 of the drainage rail 136 comprises four walls that collectively delineate an elongated generally rectangular configuration (e.g., a rail configuration). This is the case in the embodiment of FIG. 3. In such cases, the top end 126 of the drainage rail 136 can optionally include four wood header boards 146, which extend respectively along the four walls of the housing 150.

In some embodiments, the air handling unit 122 has a bottom base 152 with a downwardly directed flange 154 that extends along a perimeter of the bottom base 152. In such cases, the downwardly directed flange can optionally project downwardly into the trough of the gutter assembly. This is shown in FIG. 3, and also in FIG. 4.

The air handling unit 122 is mounted on the top ends 126 of two or more equipment rails 130, e.g., such that the bottom base 152 of the air handling unit 122 rests on the top ends 126 of such equipment rails 130. In some embodiments, a downwardly directed flange 154 of the bottom base 152 of the air handling unit 122 surrounds at least part of the top ends of those equipment rails. This is the case in FIG. 3, as well as in FIG. 4.

Preferably, the air handling unit 122 includes a heat exchanger fan 156. In such cases, at least part of the gutter assembly 140 of the drainage rail 136 can optionally be in vertical alignment with the heat exchanger fan 156. In some embodiments, at least part of the gutter assembly (e.g., a water trough thereof) is in vertical alignment with (e.g., aligned directly below) both the outdoor heat exchanger and the heat exchanger fan. This is shown in FIGS. 3 and 4. It is to be appreciated, however, that this is not required. As just one example, the outdoor heat exchanger on the air handling unit can be in a vertical orientation, in which case the fan may not be in vertical alignment with any part of the gutter assembly. Such a drip pan can be separate from (e.g., spaced apart from and/or not in fluid communication with) the gutter assembly.

Thus, in some embodiments, the air handling unit 122 includes a fan 156 configured to move outdoor air over the outdoor heat exchanger 132. Furthermore, the air handling unit preferably is in fluid communication with both a return duct and a supply duct. In some cases, the air handling unit further includes an evaporator heat exchanger configured to cool air that flows from the return duct, into the air handling unit, over the evaporator heat exchanger (which is located inside the air handling unit), out of the air handling unit, and into the supply duct. In certain embodiments of this nature, the air handling unit further includes a drip pan located directly under the evaporator heat exchanger to catch water that condenses on the evaporator heat exchanger and drips downwardly when the evaporator heat exchanger cools humid air.

In certain embodiments, the air handling unit is a gas-heat rooftop unit, such as a high turndown gas heat rooftop unit, which is configured to create water from combustion (e.g., at low turn-down rates) during ambient outdoor temperatures below 32 degrees fahrenheit. In such cases, the water trough preferably is configured to receive the water produced from the combustion.

Preferably, the outdoor heat exchanger 132 is a component of an air-source heat pump. In such cases, the outdoor heat exchanger 132 is configured to selectively serve as either an evaporator heat exchanger or a condenser heat exchanger.

In some cases, the gutter assembly 140 further includes a water drain line 158 in fluid communication with the water trough 144 of the gutter assembly. When provided, the water drain line 158 may pass through the interior rail region 160 (e.g., such that at least part of the water drain line is surrounded by the housing 150 of the drainage rail 136). This, however, is not required. In other embodiments, the gutter assembly is integrated onto an exterior side of an equipment rail and/or the water drain line is located outside the housing of the drainage rail.

In certain embodiments, the water drain line 158 passes through an opening in the roof deck 128 of the building 250. Thus, the water drain line 158 can optionally be configured to deliver water from the water trough 144 of the gutter assembly 140 into the building 250. In other cases, the water drain line may be configured to deliver water to a roof drain.

The water trough 144 of the gutter assembly 140 preferably is located alongside an upper portion of the housing 150 of the drainage rail 136. Additionally or alternatively, the water drain line 158 of the gutter assembly 140 can be located alongside a lower portion of the housing 150 of the drainage rail 136. In some embodiments, the water drain line 158 extends vertically alongside the housing 150 of the drainage rail 136. This, however, is by no means required.

The water trough 144 of the gutter assembly 140 can be disposed within the interior rail region 160 of the drainage rail 136. For example, the water trough 144 can be bounded (or defined) by one or more walls within the drainage rail 136. In some cases, the water trough 144 includes both a vertical side wall 162 and a sloped bottom wall 164. In such cases, the sloped bottom wall 164 can be configured (e.g., by virtue of its sloped configuration) to direct water flow to a drain line 158. As shown in FIG. 3, the drain line 158 can be at a lower elevation than a majority (or even an entirety) of the sloped bottom wall 164. In other cases, the water trough can simply have a flat, horizonal bottom wall. Another alternative is for the water trough to comprise two sloped, converging walls, e.g., similar to the design shown in FIG. 1. Still another alternative is for the water trough to be sloped downwardly along its length to a drain line at one end of the length of the trough.

Preferably, the gutter assembly 140 is configured to prevent water from freezing in the trough 144. For example, the trough 144 of the gutter assembly 140 can include one or more heating elements 166. When provided, the heating elements 166 can be located on one or more walls of the trough 144. Such heating elements 166 are adapted to prevent water in the trough from freezing and/or melt ice that may form in the trough. This can facilitate directing water flow to a drain line 158.

In some embodiments, an entirety of the gutter assembly 140 (or at least a water trough 144 thereof) is located vertically below (e.g., so as to be in direct vertical alignment with) the outdoor heat exchanger 132 and/or other parts of the air handling unit 122. In arrangements of this nature, the outdoor heat exchanger 132 and/or other parts of the air handling unit 122 overhang the water trough 144. This may be advantageous in terms of providing protection against hail and other airborne items (e.g., debris) striking the gutter system and/or entering the water trough. It is to be appreciated, however, that other embodiments involve a vertical outdoor heat exchanger that does not provide the same type of vertical shielding.

Further, the gutter assembly (or at least a water trough thereof) can optionally be located internally of at least one protective wall. The protective wall may be a wall of the housing 150 of the drainage rail 136, as shown in FIG. 3, or it may be a wall of the gutter assembly that is spaced outwardly from the wall of the housing. In such cases, the protective wall can provide some protection to the gutter assembly (or at least a water trough thereof) on at least one side. In some cases, the protective wall surrounds the gutter assembly (or at least a water trough thereof). Moreover, some embodiments provide a lateral shielding arrangement in combination with the above-noted type of vertical shielding arrangement. Two examples are shown in FIGS. 3 and 4.

FIG. 4 shows an outdoor rooftop HVAC equipment rail assembly 170 comprising two equipment rails 180 that are each drainage rails 196. Thus, each of the two illustrated equipment rails 180 includes a gutter assembly 190. In more detail, each equipment rail 180 comprises a housing (optionally a metal housing) 150 to which a gutter assembly 190 is integral. The equipment rail assembly 170 also includes an air handling unit 172. In FIG. 4, the air handling unit 172 includes two outdoor heat exchangers 132, which are located respectively on two opposed sides of the air handling unit 172. In the present embodiments, the two gutter assemblies 190 (or at least the two water troughs 192, 194 thereof) are located respectively beneath the two outdoor heat exchangers 132. Thus, the air handling unit 172 of FIG. 4 can be referred to as a multi-sided air handling unit, and the equipment rail assembly 170 can be referred to as a multi-sided drainage rail assembly.

Each gutter assembly 190 includes a water trough 192, 194. In FIG. 4, a first water trough 192 extends along one side of the air handling unit 172, while a second water trough 194 extends along an opposite side of the air handling unit 172. In such embodiments, the two water troughs 192, 194 preferably extend respectively along two axes that are at least substantially parallel to each other.

Thus, in the nonlimiting example of FIG. 4, the equipment rail assembly 170 includes two equipment rails 180 that are located at (e.g., so as to support) opposite sides of the air handling unit 172. Here, both equipment rails 180 are drainage rails 196 that are spaced apart and preferably are elongated such that they extend respectively along two axes that are at least substantially parallel to each other. In embodiments of this nature, there may be only two equipment rails. This, however, need not always be the case. Depending upon the particular installation, it may be desirable to provide three or more equipment rails.

Thus, in the embodiment of FIG. 4, the air handling unit 172 is mounted on the top ends of two or more equipment rails 180 that are drainage rails 196. As illustrated, each of these drainage rails 196 includes a gutter assembly 190. Each of the two gutter assemblies 190 shown in FIG. 4 can optionally have the same general configuration. Each gutter assembly 190, for example, may be configured as described above relative to the gutter assembly 140 of FIG. 3. Furthermore, the two drainage rails 196 each include a water trough 192, 194, which preferably is in fluid communication with a drain line 158. In such cases, the two drain lines may 158 extend respectively through two different openings in the roof deck 128 of the building 250. Another option is for the drain lines to extend to a roof drain.

In the embodiment of FIG. 4, the air handling unit 172 includes two heat exchanger fans 156. In such cases, at least part of the gutter assembly 190 of each drainage rail 196 can optionally be in vertical alignment with a heat exchanger fan 156. In some embodiments, at least part of each gutter assembly (e.g., a water trough thereof) is in vertical alignment with (e.g., aligned directly below) both an outdoor heat exchanger and a heat exchanger fan. This is shown in FIG. 4. It is to be appreciated, however, that this is not required. As just one example, two outdoor heat exchangers on an air handling unit can both be in vertical orientations, in which case the fans may not be in vertical alignment with any parts of the gutter assemblies.

Thus, in some embodiments, the air handling unit 172 includes two fans 156 respectively configured to move outdoor air over two outdoor heat exchangers 132. Furthermore, the air handling unit preferably is in fluid communication with both a return duct and a supply duct. In some cases, the air handling unit further includes an evaporator heat exchanger configured to cool air that flows from the return duct, into the air handling unit, over the evaporator heat exchanger (which is located inside the air handling unit), out of the air handling unit, and into the supply duct. In certain embodiments of this nature, the air handling unit further includes a drip pan located directly under the evaporator heat exchanger to catch water that condenses on the evaporator heat exchanger and drips downwardly when the evaporator heat exchanger cools humid air. Such a drip pan can be separate from (e.g., spaced apart from and/or not in fluid communication with) the gutter assembly.

In the embodiments of FIGS. 3 and 4, each drainage rail preferably has only a single water trough. Furthermore, each drainage rail in these embodiments can optionally have only a single drain line 158. It is to be appreciated, however, that these details are by no means required in all embodiments.

FIG. 5 shows a rooftop HVAC equipment rail assembly 200 that includes two equipment rails 230. FIG. 5 is representative of a group of embodiments wherein at least one of a plurality of equipment rails 236 is a drainage rail 236 having two gutter assemblies 210. Here, two gutter assemblies 210 are both located within an interior rail region 160 of a drainage rail 236. Another possibility is for two gutter assemblies to be located respectively on two opposite exterior sides of an equipment rail. In FIG. 5, each drainage rail 236 has two water troughs 204, which are positioned respectively to catch water run-off from two outdoor heat exchangers 212 of the air handling unit 208 that is supported by the drainage rails 236. Here, both water troughs 204 of each illustrated drainage rail 236 are located within an interior rail region 160 of such drainage rail 236.

In FIG. 5, the air handling unit 208 has multiple heat exchange modules, each comprising two outdoor heat exchangers 212 mounted at sloped angles so as to converge downwardly in the direction of a drainage rail 236. Furthermore, each illustrated heat exchange module includes one or more (e.g., two) fans 156 configured to move outdoor air across such module's two outdoor heat exchangers 212. In FIG. 5, the air handling unit 208 has only two such heat exchange modules, which are shown in a side-by-side arrangement. If desired, however, the air handling unit can include three or more such heat exchange modules. Reference is made to the nonlimiting example of FIG. 6. Another possibility is for the air handling unit to have just one such heat exchange module, which is supported by a dual-sided drainage rail, optionally like the one shown in FIG. 5.

In the present embodiments, the (or each) drainage rail 236 has two gutter assemblies 210 that are positioned respectively beneath two outdoor heat exchangers 212 of the air handling until 208. In more detail, for the (or each) drainage rail 236, two water troughs 204 preferably are integral to the housing 202 of such drainage rail 236. In the nonlimiting example shown in FIG. 5, the (or each) drainage rail 236 includes a top end (optionally defined by a central pedestal portion) that is located between two water troughs 204 and that supports the weight of the air handling unit 208. As noted above, the air handling unit 208 in these embodiments preferably includes two outdoor heat exchangers 212 mounted at sloped angles converging downwardly in the direction of a drainage rail 236, and one or more fans 156 preferably are provided adjacent (e.g., above) such two heat exchangers 212 so as to move air through those two heat exchangers.

Thus, in the embodiment of FIG. 5, the equipment rail assembly 200 includes multiple equipment rails 230, and two water troughs 204 are integrated into each equipment rail 130. Moreover, each water trough 204 can optionally be connected with a drain line 214. Thus, in some cases, the equipment rail assembly comprises at least one drainage rail 236 that includes two water troughs 204 and two drain lines 214. If desired, two drain lines extending respectively from two water troughs may come together so as to feed into a single drain line. When provided, the drain line(s) can be of any nature described previously in this disclosure.

FIG. 6 shows a rooftop HVAC equipment rail assembly 270 in accordance with certain embodiments of the present disclosure. Here, the assembly 270 includes at least one equipment rail 230 that is a drainage rail 236 and supports the weight of an air handling unit 218. In addition, the assembly 270 includes at least one gutter assembly 210 that does not support the weight of (e.g., is spaced apart below) the air handling unit 218. This type of gutter assembly is referred to herein as a “non-structural” gutter assembly. Preferably, the non-structural gutter assembly 210 comprises a water trough 204 integral to a housing 224 that is spaced apart from (e.g., spaced below), and thus does not support the weight of, the air handling unit 218.

It will be appreciated that the air handling unit 218 illustrated in FIG. 6 includes at least three heat exchange modules (only part of the third module is illustrated; the image of the left side of the air handling unit is broken away).

In FIG. 6, the air handling unit 218 includes a heat exchange module located above the non-structural gutter assembly 210. In the embodiment illustrated, that heat exchange module comprises two outdoor heat exchangers 222 mounted at sloped angles so as to converge downwardly in the direction of the non-structural gutter assembly 210. The water trough 204 of this non-structural gutter assembly 210 is configured to receive water that melts from both of the two overlying, adjacent outdoor heat exchangers 222 during a defrost cycle thereof.

Preferably, the water trough 204 of the non-structural gutter assembly 210 is in fluid communication with a drain line 214. The drain line 214 is shown extending through an opening in the roof deck 128. If desired, the drain line can instead be configured to deliver water to a roof drain.

The embodiment of FIG. 6 is representative of a group of embodiments wherein the water trough 204 of a non-structural gutter assembly 210 has a different configuration than a water trough 204 of a drainage rail 236. For example, the water trough 204 of the illustrated non-structural gutter assembly 210 is configured to receive water from two overlying, adjacent outdoor heat exchangers 222, whereas each water trough 204 of the illustrated drainage rail 236 is configured to receive water from only one overlying, adjacent outdoor heat exchanger 222.

Moreover, in the equipment rail assembly 270 illustrated in FIG. 6, the non-structural gutter assembly 210 has only a single water trough 204, whereas the drainage rail 236 has two water troughs 204. The water trough 204 of the non-structural gutter assembly 210 preferably includes one or more heating elements 228. Similarly, the two water troughs 204 of the drainage rail 236 preferably each include one or more heating elements 228.

Further still, the present invention provides embodiments wherein an air handling unit includes a natural gas heater vent, and a water trough (e.g., carried by or integrated into a roof curb or an equipment rail) is provided and is configured to receive water from (e.g., is located directly below) the natural gas heater vent. For example, certain embodiments provide the air handling unit in the form of a gas-heat rooftop unit, such as a high turn-down gas heat rooftop unit, which is configured to create water from combustion (e.g., at low turn-down rates) during ambient outdoor temperatures below 32 degrees Fahrenheit.

Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. An outdoor rooftop HVAC curb assembly comprising a roof curb and an air handling unit, the roof curb having a bottom end and a top end, the bottom end of the roof curb mounted on a roof deck of a building, the air handling unit mounted on the top end of the roof curb, the roof curb comprising a housing that surrounds an HVAC passage extending from inside the building, through the roof deck, and to the air handling unit, the air handling unit including an outdoor heat exchanger, the roof curb including a gutter assembly that is integral to the housing of the roof curb, the gutter assembly including a water trough alongside the housing of the roof curb, the water trough being upwardly open and located below a bottom region of the outdoor heat exchanger so as to be configured to receive water that melts from the outdoor heat exchanger during a defrost cycle thereof.

2. The outdoor rooftop HVAC curb assembly of claim 1 wherein the outdoor rooftop HVAC curb assembly further includes a supply duct and a return duct, both the supply duct and the return duct are disposed in the HVAC passage and surrounded by the housing of the roof curb, and the water trough of the roof curb is positioned at an elevation where the supply duct and the return duct are also located.

3. The outdoor rooftop HVAC curb assembly of claim 2 wherein an entirety of the gutter assembly is located at an elevation lower than an entirety of the outdoor heat exchanger.

4. The outdoor rooftop HVAC curb assembly of claim 1 wherein the top end of the roof curb includes a wood header.

5. The outdoor rooftop HVAC curb assembly of claim 4 wherein the gutter assembly is anchored to the wood header at the top end of the roof curb.

6. The outdoor rooftop HVAC curb assembly of claim 1 wherein the housing of the roof curb comprises four metal walls that collectively delineate a rectangular shape, and the top end of the roof curb includes four wood header boards respectively extending along the four metals walls of the housing of the roof curb.

7. The outdoor rooftop HVAC curb assembly of claim 1 wherein the air handling unit has a bottom base with a downwardly directed flange that extends along a perimeter of the bottom base, and the air handling unit is mounted on the top end of the roof curb such that the bottom base of the air handling unit rests on the top end of the roof curb with the downwardly directed flange at least partially surrounding the top end of the roof curb, and wherein the downwardly directed flange is located further from the HVAC passage than at least part of the gutter assembly.

8. The outdoor rooftop HVAC curb assembly of claim 1 wherein the air handling unit includes a heat exchanger fan, at least part of the gutter assembly being in vertical alignment with the heat exchanger fan.

9. The outdoor rooftop HVAC curb assembly of claim 1 wherein the gutter assembly further includes a water drain line in fluid communication with the water trough of the gutter assembly.

10. The outdoor rooftop HVAC curb assembly of claim 9 wherein the water drain line passes through an opening in the roof deck of the building, such that the water drain line is configured to deliver water from the water trough of the gutter assembly into the building.

11. The outdoor rooftop HVAC curb assembly of claim 9 wherein the water trough of the gutter assembly is located alongside an upper portion of the housing of the roof curb, and the water drain line of the gutter assembly is located alongside a lower portion of the housing of the roof curb.

12. The outdoor rooftop HVAC curb assembly of claim 1 wherein the water trough of the gutter assembly includes one or more heating elements.

13. The outdoor rooftop HVAC curb assembly of claim 1 wherein either (i) the water trough of the gutter assembly is elongated so as to extend along at least two sides of the air handling unit, or (ii) the water trough of the gutter assembly extends along one side of the air handling unit and a second water trough of the gutter assembly extends along another side of the air handling unit.

14. The outdoor rooftop HVAC curb assembly of claim 1 wherein the outdoor heat exchanger has a length, the water trough of the gutter assembly has a length, and the length of the water trough of the gutter assembly is equal to or greater than the length of the outdoor heat exchanger.

15. The outdoor rooftop HVAC curb assembly of claim 1 wherein the air handling unit includes a fan configured to move outdoor air over the outdoor heat exchanger, and the air handling unit is in fluid connection with both a return duct and a supply duct, wherein the air handling unit has a bottom side attached to both the return duct and the supply duct, wherein the air handling unit further includes an evaporator heat exchanger configured to cool air that flows from the return duct, into the air handling unit, over the evaporator heat exchanger, out of the air handling unit, and into the supply duct, and the air handling unit further includes a drip pan located directly under the evaporator heat exchanger to catch water that condenses on the evaporator heat exchanger and drips downwardly when the evaporator heat exchanger cools humid air.

16. The outdoor HVAC assembly of claim 1 wherein the outdoor heat exchanger is a component of an air-source heat pump, such that the outdoor heat exchanger is configured to selectively serve as either an evaporator heat exchanger or a condenser heat exchanger.

17. An outdoor rooftop HVAC equipment rail assembly comprising a plurality of equipment rails and an air handling unit, each of the equipment rails having a bottom end and a top end, the bottom ends of the equipment rails being mounted on a roof deck of a building, the air handling unit being mounted on the top ends of the equipment rails, the air handling unit including an outdoor heat exchanger, at least one of the equipment rails being a drainage rail comprising a housing to which a gutter assembly is integral, the gutter assembly including a water trough alongside the housing of the drainage rail, the water trough being upwardly open and located below a bottom region of the outdoor heat exchanger so as to be configured to receive water that melts from the outdoor heat exchanger during a defrost cycle thereof.

18. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the water trough is surrounded by the housing of the drainage rail.

19. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein an entirety of the gutter assembly is located at an elevation lower than an entirety of the outdoor heat exchanger.

20. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the top end of the drainage rail includes a wood header.

21. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the housing of the drainage rail comprises four metal walls that collectively delineate an elongated generally rectangular shape, and the top end of the drainage rail includes four wood header boards respectively extending along the four metals walls of the housing of the drainage rail.

22. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the air handling unit is equipped with a bottom base having a downwardly directed flange that extends along a perimeter of the bottom base, and the air handling unit is mounted on the top ends of the equipment rails such that the bottom base of the air handling unit rests on the top ends of the equipment rails with the downwardly directed flange surrounding at least part of the top ends of the equipment rails, and wherein the downwardly directed flange projects downwardly into the trough of the gutter assembly of the drainage rail.

23. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the air handling unit is equipped with a heat exchanger fan, and at least part of the gutter assembly of the drainage rail is in vertical alignment with the heat exchanger fan.

24. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the housing of the drainage rail surrounds an interior rail region, the water trough is located in the interior rail region, and the gutter assembly further includes a water drain line in fluid communication with the water trough of the gutter assembly, the water drain line passing through the interior rail region.

25. The outdoor rooftop HVAC equipment rail assembly of claim 24 wherein the water drain line passes through an opening in the roof deck of the building, such that the water drain line is configured to deliver water from the water trough of the gutter assembly into the building.

26. The outdoor rooftop HVAC equipment rail assembly of claim 24 wherein the water trough of the gutter assembly is located alongside an upper portion of the housing of the drainage rail, and the water drain line of the gutter assembly is located alongside a lower portion of the housing of the drainage rail.

27. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the water trough of the gutter assembly includes one or more heating elements.

28. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the water trough of the gutter assembly extends along one side of the air handling unit and a second water trough of the gutter assembly extends along an opposite side of the air handling unit.

29. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the outdoor heat exchanger has a length, the water trough of the gutter assembly has a length, and the length of the water trough of the gutter assembly is equal to or greater than the length of the outdoor heat exchanger.

30. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the air handling unit includes a fan configured to move outdoor air over the outdoor heat exchanger, and the air handling unit is in fluid connection with both a return duct and a supply duct, wherein the air handling unit further includes an evaporator heat exchanger configured to cool air that flows from the return duct, into the air handling unit, over the evaporator heat exchanger, out of the air handling unit, and into the supply duct, and the air handling unit further includes a drip pan located directly under the evaporator heat exchanger to catch water that condenses on the evaporator heat exchanger and drips downwardly when the evaporator heat exchanger cools humid air.

31. The outdoor rooftop HVAC equipment rail assembly of claim 17 wherein the outdoor heat exchanger is a component of an air-source heat pump, such that the outdoor heat exchanger is configured to selectively serve as either an evaporator heat exchanger or a condenser heat exchanger.