CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is an international application of, and claims priority to and the benefit of, U.S. Application No. 63/322,291, filed March 22, 2022, the entirety of which is hereby incorporated by reference.

FIELD OF TECHNOLOGY

[0002] The disclosed technology relates generally to electrical heating element assemblies for heating, ventilation, and air conditioning (HVAC) systems and, more particularly, to electrical heating element assemblies used in air handling units having axial fans.

BACKGROUND

[0003] Air handling units (sometimes referred to as air handlers, fan coil units, etc.) are commonly used in heating, ventilation, and air conditioning (HVAC) systems to regulate and circulate air throughout a building or ventilated space. As illustrated in FIG. 1A, existing air handling units 100 commonly include an enclosure 102 having an air inlet 104 and an air outlet 106. The enclosure 102 houses a blower 108 (e.g., a centrifugal fan such as a forward curved fan, a backward curved fan) and a heat exchanger coil 110. The heat exchanger coil 110 is connected via refrigerant lines to an outdoor heat exchanger coil 112 (i.e., a heat exchanger installed in a location outside of, and separate from, the enclosure 102) and is configured to facilitate heat exchange between air passed over the heat exchanger coil 110 and refrigerant that is circulated through the heat exchanger coil 110. For the sake of clarity, various components of the refrigerant system such as a compressor, an expansion valve, and tubing have been omitted. Depending on whether the HVAC system is in a cooling mode or a heating mode, the heat exchanger coil 110 can either remove heat from air that is passed over the heat exchanger coil 1 10 (i.e., the cooling mode) or add heat to air that is passed over the heat exchanger coil 110 (i.e., the heating mode). Air is moved over the heat exchanger coil 110 by the blower 108, which draws air into the enclosure 102 through the air inlet 104 and directs the cooled or heated air to the ventilated space through the air outlet 106, which can be connected to a duct system, for example. [0004] Some air handling units 100 include heating element assemblies 114 located at the outlet of the blower 108 to add heat to the high velocity air as it is passed through the air handling unit 100. These heating element assemblies 114 are typically used as a supplemental or emergency heat source and include one or more heating elements 116 (i.e., electrical resistive heating elements). As shown in FIG. IB, many existing heating element assemblies 114 have heating elements 116 that are arranged to extend across the rectangular shape of the outlet of the blower 108 or the enclosure 102. As air exits the rectangular outlet of the blower 108 at a high velocity, the air is directed over the heating elements 116 and the air is heated before being directed to the ventilated space. The high air velocity proximate the outlet of the blower 108 helps to prevent the heating elements 116 from overheating.

[0005] To help reduce the amount of energy consumed by the air handling unit 100, some recent designs of air handling units 100 have attempted to utilize axial fans rather than blowers 108. Unfortunately, traditional heating element assemblies 114 do not work well with axial fans because the configuration of the heating element assembly 114 does not facilitate effective transfer heat to the air exiting the dd outlet of the axial fan. For instance, a heating element assembly 114 arranged in a rectangular configuration will either have gaps where the air exiting the axial fan can escape past the heating element assembly 114 without being sufficiently heated or the rectangular heating element assembly 114 will have heating elements 116 positioned in locations where air is not actively passed over the heating elements 116 (e.g., at corners of an oversized rectangular heating element assembly 114). [0006] What is needed, therefore, is a heating element design that is capable of effectively facilitating heat transfer in an air handling unit having an axial fan. These and other problems are addressed by the technology disclosed herein.

SUMMARY

[0007] The disclosed technology relates generally to an axial fan assembly for an air handling unit. The axial fan assembly can include an axial fan that is configured to direct a flow of air along an airflow path through the axial fan assembly and a stator that is disposed in the airflow path downstream of the axial fan to at least partially straighten the flow of the air. The axial fan assembly can include a heating element assembly disposed in the airflow path downstream of the stator. The heating element assembly can include a heating element having a generally toroidal shape having an outer diameter less than an inner diameter of a casing disposed around the axial fan. The heating element assembly can have one or more supports configured to space the heating element a distance downstream from the stator to form a gap between the stator and the heating element. The gap can be approximately six inches from the stator.

[0008] The heating element can be a first heating element and the heating element assembly can include a second heating element. The one or more supports can be configured to space the second heating element the distance downstream from the stator forming a gap between the stator and the second heating element. The first heating element and second heating element can be coaxial and/or coplanar.

[0009] The one or more supports can be attached to the stator. The one or more supports can include a plurality of vertical supports attached to the stator and extending upward to the heating element. The plurality of vertical supports can be configured to support the heating element. The plurality of vertical supports can include a clip configured to attach the plurality of vertical supports to the stator.

[0010] The one or more supports can include a central support hub and central supports extending radially outward from the central support hub to the heating element assembly. The central supports can be configured to support the heating element. The central support hub can be attached to a central hub of the stator.

[0011] The one or more supports can include a plurality of lateral supports extending radially inward from a casing disposed around the axial fan and the stator. The plurality of lateral supports can be configured to support the heating element.

[0012] The heating element assembly can be disposed at least partially within an outlet nozzle of the axial fan assembly. The outlet nozzle can be disposed downstream of the axial fan and the stator. The outlet nozzle can include an inlet having a first diameter and an outlet having a second diameter. The second diameter can be greater than the first diameter. The outlet nozzle can include an integrated heating element that is configured to heat the outlet nozzle.

[0013] The stator can include vanes having an integrated heating element assembly disposed in a vane of the stator. The stator can include vanes having an integrated heating element assembly disposed along an outer surface of the stator. The integrated heating element assembly can include a thermally-conductive ceramic material. [0014] The axial fan assembly can include a heat shield disposed between the heating element assembly and an electrical motor of the axial fan.

[0015] The disclosed technology can include a heating element assembly for an air handling unit. The heating element assembly can include a resistive heating element comprising a generally toroidal shape. The generally toroidal shape can have an outer diameter that is less than an inner diameter of a casing disposed around an axial fan. The heating element assembly can include a central support hub disposed proximate a center of the resistive heating element and a plurality of central supports extending radially outward from the central support hub to the resistive heating element. The plurality of central supports can be configured to support the resistive heating element.

[0016] The heating element assembly can include a second resistive heating element assembly and the plurality of central supports can extend radially outward from the central support hub to the second resistive heating element. The plurality of central support can be configured to support the second resistive heating element. The first resistive heating element assembly and second resistive heating element assembly can be coaxial and/or coplanar.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various aspects of the presently disclosed subject matter and serve to explain the principles of the presently disclosed subject matter. The drawings are not intended to limit the scope of the presently disclosed subject matter in any manner.

[0018] FIG. 1A illustrates a schematic diagram of an existing air handling unit of an HVAC system.

[0019] FIG. IB illustrates a schematic diagram of an existing heating element assembly. [0020] FIG. 2A illustrates a schematic diagram of an example air handling unit of an HVAC system with an axial fan and heating element assembly, in accordance with the disclosed technology.

[0021] FIG. 2B illustrates a schematic diagram of an example heating element assembly, in accordance with the disclosed technology.

[0022] FIG. 3A illustrates a top view of an axial fan assembly having a heating element assembly for an air handling unit, in accordance with the disclosed technology. [0023] FTG. 3B illustrates a sectional view of the axial fan assembly of FIG. 3 A taken along line A-A, in accordance with an example of the disclosed technology.

[0024] FIG. 4 illustrates another top view of an axial fan assembly having a heating element assembly for an air handling unit, in accordance with the disclosed technology.

[0025] FIG. 5 illustrates another sectional view of an axial fan assembly, in accordance with an example of the disclosed technology.

[0026] FIG. 6A illustrates another top view of an axial fan assembly having a heating element assembly for an air handling unit, in accordance with the disclosed technology.

[0027] FIG. 6B illustrates a detail view of a heating element assembly and stator, in accordance with the disclosed technology.

[0028] FIG. 6C illustrates a sectional view of the heating element assembly and the stator of FIG. 6B, in accordance with the disclosed technology.

[0029] FIG. 7 illustrates a side sectional view of a stator having an integrated heating element assembly, in accordance with the disclosed technology.

[0030] FIG. 8 illustrates a sectional view of an outlet nozzle of the axial fan having an integrated heating element assembly, in accordance with the disclosed technology.

DETAILED DESCRIPTION

[0031] The disclosed technology includes heating element assemblies used in air handling or fan coil units having an axial fan. In particular, the disclosed technology includes various examples of electric heating element assemblies that are configured to effectively transfer heat to air moved through the air handling unit by the axial fan. For example, the disclosed technology' includes circular-shaped heating element assemblies disposed proximate an outlet of the axial fan and positioned to effectively transfer heat to the air exiting the axial fan. The disclosed technology also includes various mounting features configured to ensure the heating element assembly is positioned in a portion of the airflow path directed through the axial fan that helps to increase the heat transfer between the heating elements and the air. Further, the disclosed technology includes stators and inlet/outlet nozzles that include integrated heating elements. Further configurations and advantages of the disclosed technology will become apparent throughout this disclosure.

[0032] Although various aspects of the disclosed technology are explained in detail herein, it is to be understood that other aspects of the disclosed technology are contemplated. Accordingly, it is not intended that the disclosed technology is limited in its scope to the details of construction and arrangement of components expressly set forth in the following description or illustrated in the drawings. The disclosed technology can be implemented and practiced or carried out in various ways. In particular, the presently disclosed subject matter is described in the context of being a heating element assembly of an air handling unit having an axial fan. The present disclosure, however, is not so limited, and can be applicable in other contexts such as fan coil units, industrial process heating and cooling systems, automotive heating systems, etc. Accordingly, when the present disclosure is described in the context of a heating element assembly of an air handling unit having an axial fan, it will be understood that other implementations can take the place of those explicitly referred to herein.

[0033] It should also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. References to a composition containing “a” constituent is intended to include other constituents in addition to the one named.

[0034] Also, in describing the disclosed technology, terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

[0035] Ranges may be expressed herein as from “about” or “approximately” or “substantially” one particular value and/or to “about” or “approximately” or “substantially” another particular value. When such a range is expressed, the disclosed technology can include from the one particular value and/or to the other particular value. Further, ranges described as being between a first value and a second value are inclusive of the first and second values. Likewise, ranges described as being from a first value and to a second value are inclusive of the first and second values.

[0036] Herein, the use of terms such as “having,” “has,” “including,” or “includes” are open-ended and are intended to have the same meaning as terms such as “comprising” or “comprises” and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as “can” or “may” are intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such. [0037] As used herein, the term “circular” is meant to refer to a shape generally resembling a circle. As will be appreciated, however, the term “circular” can include other shapes that do not necessarily form a perfect circle. As non-limiting examples, the term “circular” can be construed to include generally rounded, elliptical, or other similar shapes. [0038] The components described hereinafter as making up various elements of the disclosed technology are intended to be illustrative and not restrictive. Many suitable components that would perform the same or similar functions as the components described herein are intended to be embraced within the scope of the disclosed technology. Such other components not described herein can include, but are not limited to, similar components that are developed after development of the presently disclosed subject matter.

[0039] Referring now to the drawings, in which like numerals represent like elements, the present disclosure is herein described. FIG. 2A illustrates a schematic diagram of an air handling unit 200 of an HVAC system having an axial fan assembly 220. The axial fan assembly 220 can include at least an axial fan 222, a stator 224, and a heating element assembly 226. As will be described in greater detail herein, the heating element assembly 226 can be configured to heat the air moved by the axial fan 222 through the HVAC system. The air handling unit 200 can include an enclosure 202 having an inlet 204 and an outlet 206. The enclosure 202 can be configured to house at least the axial fan assembly 220 and a heat exchanger coil 210. As shown, the axial fan 222 can be mounted in the enclosure 202 in an airflow path downstream of the heat exchanger coil 210. Alternatively, the axial fan 222 can be mounted in an airflow path upstream of the heat exchanger coil 210. Furthermore, whether mounted upstream or downstream of the heat exchanger coil 210, the axial fan 222 can be mounted vertically (e.g., such that the central axis of the axial fan 222 is generally parallel to the central axis of the enclosure 202) above the heat exchanger coil 210, vertically below the heat exchanger coil 210, or beside the heat exchanger coil 210 (e.g., if the air handling unit 200 is oriented horizontally) depending on the configuration. The air can be moved through the air handling unit 200 by the axial fan 222 in a first general direction (e.g., vertically upward, vertically downward, from a first side of the air handling unit to a second side of the air handling, etc.) or in a second general direction that is opposite from the first general direction depending on the configuration of the air handling unit 200. [0040] One of skill in the art will appreciate that the axial fan 222 can be any type of axial fan that is configured to move air from the inlet 204, across the heat exchanger coil 210, and out the outlet 206. For example, the axial fan 222 can be a propeller axial fan, a tube axial fan, a vane axial fan, a backward curved axial fan, or any other suitable type of axial fan for the application. In other words, the axial fan 222 can be configured to move air in an axial direction, parallel to a axis about which blades of the axial fan 222 rotate. The axial fan 222 can be a shrouded fan (i.e., the axial fan 222 can include a shroud disposed around an outer edge of the fan blades) or the axial fan 222 can be a non-shrouded fan.

[0041] The heat exchanger coil 210 can be configured to exchange heat with the refrigerant circulated through the heat exchanger coil 210 and air passed over the heat exchanger coil 210. The heat exchanger coil 210 can be any type of heat exchanger that can facilitate heat exchange between refrigerant and air and/or water and air. The heat exchanger coil 210, for example, can be an A-coil, an N-coil, a Z-coil, a V-Coil, a slab coil, a microchannel coil, or any other suitable type of heat exchanger for the application. Furthermore, the heat exchanger coil 210 can be made of any suitable material for the application. For example, the heat exchanger coil 210 can be made of aluminum, copper, titanium, stainless steel, cupronickel, carbon steel, composite materials, or other suitable materials.

[0042] The heat exchanger coil 210 can be in fluid communication with an outdoor coil 212 that can be configured to facilitate heat exchange between a refrigerant that is circulated through the outdoor coil 212 and air that is passed over the outdoor coil 212. Although described as being an outdoor coil 212, one of skill in the art will appreciate that the outdoor coil 212 can be located in any suitable location to facilitate heat transfer between the refrigerant and air or another fluid. For example, the outdoor coil 212 can be located outside of a building, inside of a building (e.g., an attic, a garage, etc.), under the ground (e.g., a ground source heat pump), or in any other suitable location for the application. Furthermore, although described herein as exchanging heat between the refrigerant and air, the outdoor coil 212 can be configured to exchange heat between the refrigerant and any suitable fluid (e.g., water, glycol, etc.).

[0043] The heat exchanger coil 210 can be configured to function as an evaporator or a condenser depending on the particular application. As a non-limiting example, the heat exchanger coil 210 can be part of an air conditioning system and can be configured to perform a cooling function. Alternatively or in addition, the heat exchanger coil 21 can be part of a heat pump system and can be configured to perform both a cooling and a heating function. For example, if the temperature of the air within the ventilated space is greater than a predetermined high temperature, the heat exchanger coil 210 can be configured to function as an evaporator to absorb heat from the air passed across the heat exchanger coil 210, thereby providing cooled air to the ventilated space. On the other hand, if the temperature of the air within the ventilated space is less than a predetermined low temperature, the heat exchanger coil 210 can be configured to function as a condenser and provide heat to the air passed across the heat exchanger coil 210, thereby providing heated air to the ventilated space. The predetermined high temperature can be the same temperature as, or a greater temperature than, the predetermined low temperature.

[0044] As described previously, the axial fan assembly 220 can include a stator 224. The stator 224 can be positioned in an airflow path downstream of the axial fan 222 and can be configured to enable straightening of the air downstream of the axial fan 222. For example, the stator 224 can comprise a plurality of vanes that are sized and positioned to direct the air moved by the axial fan 222 such that the flow of the air becomes straighter in a direction generally parallel with a longitudinal axis of the axial fan 222 from a first side of the stator 224 to a second side of the stator 224. Because the axial fan 222 directs the air through the stator 224, the air flow path can be straightened prior to passing through the remainder of the HVAC system, including the heating element assembly 226.

[0045] As illustrated in FIG. 2A, the heating element assembly 226 can be positioned downstream of the stator 224 such that air moved by the axial fan 222 and directed through the stator 224 is heated by the heating element assembly 226. As illustrated in FIG. 2B, the heating element assembly 226 can be formed in a generally circular shape to conform to the circular outlet of the axial fan 222. In other words, the heating element assembly 226 can have an outer diameter that is less than or equal to an inner diameter of a casing extending around the axial fan 222. In this way, the heating element assembly 226 can be positioned entirely, or almost entirely, in the high velocity airflow path of the axial fan 222 such that the heating element assembly 226 sufficiently heats the air moved over the heating element assembly 226 and reduces inefficiencies which can be introduced if some of the heating element assembly 226 is not positioned in the high velocity airflow path. In other examples, the heating element assembly 226 can have an aperture extending through the center of the heating element assembly 226 and form a generally toroidal shape (a shape resembling a torus). [0046] The heating element assembly 226 can include any type of suitable heating element for the application. For example, the heating element assembly 226 can include metallic resistance heating elements, ceramic heating elements, thick film resistance heaters, polymer positive temperature coefficient (PTC) heating elements, or any other suitable type of heating element for the particular application. Furthermore, the heating element assembly 226 can include sheathed heating elements (e.g., tubular heating elements), unsheathed heating elements (e.g., bare wire heating elements), or some combination thereof, depending on the particular application. As non-limiting examples, the heating element assembly 226 can include a heating element that is formed into a generally circular or rounded shape to mirror the shape of the circular axial fan 222. For example, the heating element assembly 226 can be formed such that the overall shape of the heating element assembly 226 forms a helical shape, a double helical shape, a circular shape, a generally oval shape, generally toroidal shape, or any other suitable shape for the application.

[0047] FIG. 3A illustrates a top view of an axial fan assembly 220 having a heating element assembly 226 while FIG. 3B illustrates a sectional view of the axial fan assembly 220 shown in FIG. 3A taken along line A-A, in accordance with an example of the disclosed technology. As illustrated in FIGs. 3A and 3B, the axial fan assembly 220 can include an axial fan 222, a stator 224, a stator hub 325, a motor assembly 328, and a fan shaft 329 connecting the motor assembly 228 to the axial fan 222. The stator hub 325 can be positioned at the center of the stator 224 such that the vanes of the stator 224 can extend from the stator hub 227 to the inside surface of the casing 330. The stator hub 325 can be configured to support the vanes of the stator 224. The axial fan assembly can further include a fan casing 330 having an inlet 332 and an outlet 334. The fan casing 330 can be disposed around the axial fan 222, the stator 224, the stator hub 325, the motor assembly 328, and the fan shaft 329 to help guide the air through the axial fan assembly 220 from the inlet 332 to the outlet 334. The fan casing 330 can be supported by a fan deck 336 when the axial fan assembly 220 is mounted in the enclosure 202 of the air handling unit 200.

[0048] As illustrated in FIG. 3B, the heating element assembly 226 can be positioned in an air flow path downstream of both the axial fan 222 and the stator 224. In this way, the stator 224 can straighten a flow of the air prior to the air being heated by the heating element assembly 226. Furthermore, the heating element assembly 226 can comprise a generally circular shape such that the heating element assembly 226 is entirely disposed in the high velocity airflow path of the axial fan 222. Tn other words, by having a generally circular shape, the heating element assembly 226 can positioned such that approximately all of the heating surface of the heating element assembly 226 is positioned in the air flow path rather than being outside of the airflow path or obstructed by other components which could block the airflow from passing over the heating element assembly 226. For example, by having a generally circular shape, the heating element assembly 226 can be disposed such that the motor assembly 326 does not obstruct the air flow passed over the heating element assembly 226.

[0049] The motor assembly 326 can be any type of motor assembly suitable for the particular application. For example, the motor assembly 326 can be a brushed or brushless motor and can be power by an alternating current (AC) or direct current (DC) power source. Furthermore, the motor assembly 326 can include a shaft (i.e., fan shaft 329) or the motor assembly 326 can be an external rotor motor that does not require a shaft to cause the axial fan 222 to rotate.

[0050] The heating element assembly 226 can be sized and positioned to ensure a sufficient amount of the airflow passing through the axial fan assembly 220 is sufficiently heated. For example, the heating element assembly 226 can include a single heating element assembly 226 that is sized and positioned to ensure a majority of the air is passed over the heating element assembly 226 to be heated. As another example illustrated in FIG. 4, the heating element assembly 226 can include two or more heating element assemblies 226A, 226B to ensure the air is sufficiently heated. If the heating element assembly 226 includes two or more heating element assemblies 226A, 226B, the heating elements assemblies 226A, 226B can be aligned concentrically. In other words, the heating elements assemblies 226A, 226B can be coaxial. The heating elements assemblies 226 A, 226B can be spaced the same distance from the axial fan assembly 220 (i.e., the heating elements assemblies 226 A, 226B can be coplanar). Alternatively, the heating element assemblies 226A, 226B can be spaced a different distances from the axial fan assembly 220 such that a first heating element assembly 226A is positioned in an airflow path nearer the axial fan assembly 220 than the second heating element assembly 226B.

[0051] To help further ensure the heating element assembly 226 is able to sufficiently heat the air moved by the axial fan 222, the heating element assembly 226 can be positioned in the airflow path at a location where the flow of the air is likely to be turbulent As will be appreciated by one of skill in the art, by positioning the heating element assembly 226 at a location where the air is likely to be turbulent, the rate of heat transfer between the heating element assembly 226 and the air can be greater than when compared to being positioned in a laminar air flow path. As illustrated in FIG. 3B, the heating element assembly 226 can be placed approximately a distance X downstream of the stator 224 to ensure the airflow is generally turbulent as it is passed over the heating element assembly 226 but to also help prevent the motor assembly 328 from becoming overheated due to radiant heat produced by the heating element assembly 226. As anon-limiting example, the heating element assembly 226 can be approximately six inches (i.e., the distance X can be approximately six inches) downstream from the stator 224. In other examples, the distance X can be approximately one inch, two inches, three inches, four inches, five inches, ten inches, or any other suitable distance to ensure the airflow is sufficiently turbulent and that radiant heat generated by the heating element assembly 226 does not cause the motor assembly 328 to overheat. In yet other examples, the distance X can be approximately between one inch and twelve inches, between three inches and nine inches, between four inches and eight inches, between five inches and seven inches, between five and a half inches and six and a halve inches, or any other suitable range of distances to ensure the airflow is sufficiently turbulent and that radiant heat generated by the heating element assembly 226 does not cause the motor assembly 328 to overheat.

[0052] As another non-limiting example, the heating element assembly 226 can be positioned downstream of the axial fan 222 but upstream of the stator 224 as illustrated in FIG. 5. By positioning the heating element assembly 226 downstream of the axial fan 222 but upstream of the stator 224, the airflow passed over the heating element assembly 226 is likely to be sufficiently turbulent to enable sufficient heat transfer between the heating element assembly 226 and the air.

[0053] As illustrated in FIG. 5, the axial fan assembly 220 can include a heat shield 540 that can be disposed between the heating element assembly 226 and the motor assembly 228 to help ensure the motor assembly 328 does not become overheated when the heating element assembly 226 is heating the air. The heat shield 540 can be made from any suitable material including plastics, metals, foam, ceramic, composite material, or any other suitable material. Furthermore, the heat shield 540 can be shaped to direct heated air away from the motor assembly 328 to further ensure the motor assembly 328 does not become overheated. [0054] FTGs. 6A-6C illustrate various mounting features that can ensure the heating element assembly 226 is positioned above the stator 224 at a correct location. FIG. 6A illustrates a top view of the axial fan assembly 220, FIG. 6B illustrates a detailed side view of the stator 224 and heating element assembly 226, and FIG. 6C illustrates a sectional view of the stator 224 and the heating element assembly 226. As illustrated in FIG. 6A, the axial fan assembly 220 can include central supports 642 that extend radially outward from a support hub 640 to the heating element assembly 226 and lateral supports 644 that extend radially inward from the casing 330 to the heating element assembly 226. Furthermore, as illustrated in FIG. 6C, the axial fan assembly 220 can include vertical supports 646 that can be attached to the stator 224 and extend upward to the heating element assembly 226. The axial fan assembly 220 can include one, some, or all of the central supports 642, lateral supports 644, or vertical supports 646 to ensure the heating element assembly 226 is positioned above the stator at a correct location. Furthermore, as illustrated in FIGs. 6B and 6C, at least the vertical supports 646 can be configured to position the heating element assembly 626 a sufficient distance X above the stator 224 to ensure the heating element assembly 226 is positioned in a portion of the air flow path downstream of the stator 224 that is likely to have a turbulent flow as previously described. The distance X can be the same distance X previously descnbed herein. That is, the distance X can be approximately six inches in some examples. In other examples, the distance X can be approximately one inch, two inches, three inches, four inches, five inches, ten inches, or any other suitable distance to ensure the airflow is sufficiently turbulent and that radiant heat generated by the heating element assembly 226 does not cause the motor assembly 328 to overheat. In yet other examples, the distance X can be approximately between one inch and twelve inches, between three inches and nine inches, between four inches and eight inches, between five inches and seven inches, between five and a half inches and six and a halve inches, or any other suitable range of distances to ensure the airflow is sufficiently turbulent and that radiant heat generated by the heating element assembly 226 does not cause the motor assembly 328 to overheat. The central supports 642 and the lateral supports 644 can also be configured to position the heating element assembly 626 the sufficient distance X above the stator 224.

[0055] The support hub 640, the central supports 642, the lateral supports 644, and the vertical supports 646 can each be made from plastic, metal, composite material, or other suitable material for the application. The central supports 642, the lateral supports 644, and the vertical supports 646 can each be made from thermally insulative material, coated with a thermally insulative coating, and/or include a thermally insulative component proximate the heating element assembly 226. In this way, heat generated from the heating element assembly can be prevented from damaging the central supports 642, the lateral supports 644, and the vertical supports or other components of the axial fan assembly 220.

[0056] As illustrated in FIG. 6A, the support hub 640 can be positioned proximate the central axis of the axial fan assembly 220 and can be integrated with, or separate from, the stator hub 325 previously described. If the support hub 640 is integrated with the stator hub 325, the support hub 640 can support both the vanes of the stator 224 and the central supports 642. If the support hub 640 is separate from the stator hub 325, the support hub 640 can be positioned above the stator hub 325 (as illustrated in FIG. 6A) and may or may not be attached to the stator hub 325. The central supports 642 can be attached to the support hub 640 and extend radially outward from the support hub 640 to attach to and support the heating element assembly 226. The central supports 642 can be configured to support the heating element assembly 226 alone, or the central supports 642 can be configured to support the heating element assembly 226 along with the lateral supports 644 and vertical supports 646. The lateral supports can be attached to the casing 330 of the axial fan assembly 220 and extend radially inward to the heating element assembly 226 to attach to and support the heating element assembly. Similar to the central supports 642, the lateral supports 644 can be configured to support the heating element assembly 226 alone, or the lateral supports 644 can be configured to support the heating element assembly 226 along with the central supports 642 and vertical supports 646.

[0057] As illustrated in FIGs. 6B and 6C, the vertical supports 646 can be configured to attach to the vanes of the stator 224 and support the heating element assembly 226. The vertical supports 646, for example, can be clips configured to attach to the stator 224 and support the heating element assembly 226 a sufficient distance X above the stator 224 to ensure the heating element assembly 226 is positioned in an area of the flow path downstream of the stator 224 that has a turbulent flow. The distance X can be the same distance X previously described herein. That is, the distance X can be approximately six inches in some examples. In other examples, the distance X can be approximately one inch, two inches, three inches, four inches, five inches, ten inches, or any other suitable distance to ensure the airflow is sufficiently turbulent and that radiant heat generated by the heating element assembly 226 does not cause the motor assembly 328 to overheat. The vertical supports 646 can also be affixed to the stator 224 using fasteners, adhesive, a weld, a clamp, or any other suitable attachment method.

[0058] FIG. 7 illustrates a side sectional view of a vane of the stator 224 having an integrated heating element assembly 726, in accordance with the disclosed technology. As illustrated in FIG. 7, the vanes of the stator 224 can have a heating element assembly 726 that is disposed inside of the vane itself. In this way, the stator 224 can be heated by the heating element assembly 726 such that the air passed over the stator 224 can be heated by the stator 224. As will be appreciated, the vanes of the stator 224 can be made from a thermally conductive material such as a metal or composite material to permit heat generated by the integrated heating element assembly 726 to be transferred to air passed over the stator 224. By integrating the heating element assembly 726 into the stator 224, the axial fan assembly 220 can have a more compact design and require less space within the enclosure 202 of the air handling unit 200.

[0059] Although not shown, the stator 224 can alternatively or additionally include an integrated heating element assembly 726 that can be disposed along an outer surface of the vanes of the stator 224. For example, the integrated heating element assembly 726 can be disposed along a side of the vanes or wrapped around the vanes of the stator 224. As another example, the integrated heating element assembly 726 can comprise a thermally-conductive ceramic coating dispersed over at least a portion of the outer surface of the vanes of the stator 224. Similar to the heating element assembly 226, the ceramic coating can be configured to generate heat through electrical resistance. In this way, the integrated heating element assembly 726 can transfer heat to air passed over the stator 224 without requiring a significant amount of space.

[0060] FIG. 8 illustrates a sectional view of an outlet nozzle 834 of the axial fan assembly 220 having an integrated heating element assembly 826, in accordance with the disclosed technology. The outlet nozzle 834 can be attached to the casing 330 proximate the outlet 334 and comprise a first diameter nearest the outlet 334 of the casing 330 that is similar to the diameter of the outlet 334. The outlet nozzle 834 can include a second diameter disposed distal from the outlet 334 that is larger than the first diameter and the outlet nozzle 834 can be sloped or curved between the first diameter and the second diameter. In this way, the air flow path can gradually expand as it passed through the outlet nozzle 834. As shown in FIG. 8, the heating element assembly 826 can be disposed inside of the outlet nozzle 834 and be configured to heat the outlet nozzle 834 such that the outlet nozzle 834 can transfer heat to the air passed through the outlet nozzle 834. As will be appreciated, the outlet nozzle can be made from a thermally conductive material such as a metal or composite material.

[0061] Although not shown, the axial fan assembly 220 can further include an inlet nozzle having an integrated heating element assembly 826 similar to the outlet nozzle 834. The inlet nozzle can be attached to the casing 330 proximate the inlet 332 and comprise a first diameter nearest the inlet 332 of the casing 330 that is similar to the diameter of the inlet 332. The inlet nozzle can include a second diameter disposed distal from the inlet 332 that is larger than the first diameter and the inlet nozzle can be sloped or curved between the first diameter and the second diameter. In this way, the air flow path can be allowed to gradually reduce or converge as it passes through the inlet nozzle into the axial fan assembly 220. Similar to the outlet nozzle 834, the heating element assembly 826 can be disposed inside of the inlet nozzle and be configured to heat the inlet nozzle such that the inlet nozzle can transfer heat to the air passed through the inlet nozzle. As will be appreciated, the inlet nozzle can be made from a thermally conductive material such as a metal or composite material.

[0062] Alternatively or in addition, the outlet nozzle 834 and/or the inlet nozzle can also include a heating element assembly 226 that is disposed across an inwardly-facing surface of the outlet nozzle 834 and/or inlet nozzle. For example, a heating element assembly 226 can be disposed across the surface of the outlet nozzle 834 and/or inlet nozzle that will have the air passed over it by the axial fan 222. In this way, the outlet nozzle 834 and/or the inlet nozzle can heat the air pass through it.

[0063] The axial fan assembly 220 can include one, some, or all of the various heating element arrangements described herein. That is, the axial fan assembly 220 can include a heating element assembly 226 placed upstream and/or downstream of the stator, an integrated heating element assembly 726 disposed within the vanes of the stator 224, and/or an integrated heating element assembly 826 disposed in an outlet nozzle 834 and/or an inlet nozzle. That is, each of the example heating element assemblies described herein can be used individually or in combination with another heating element assembly described herein.

[0064] While the present disclosure has been described in connection with a plurality of exemplary aspects, as illustrated in the various figures and discussed above, it is understood that other similar aspects can be used, or modifications and additions can be made to the described subject matter for performing the same function of the present disclosure without deviating therefrom. In this disclosure, methods and compositions were described according to aspects of the presently disclosed subject matter. But other equivalent methods or compositions to these described aspects are also contemplated by the teachings herein. Therefore, the present disclosure should not be limited to any single aspect, but rather constmed in breadth and scope in accordance with the appended claims.