AIR HANDLING UNIT FOR USE WITH AN AIR CONDITIONING SYSTEM

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation-in-part of U.S. Non-provisional application Ser. No. 18/745,286 filed on Jun. 17, 2024, which claims priority to U.S. Provisional Application 63/511,199, filed on Jun. 30, 2023. The content of each of the above applications is hereby expressly incorporated by reference herein in its entirety.

TECHNICAL FIELD

This invention relates to an air handling unit and more particularly, to an air handling unit with a diagonal flow fan for use with an air conditioning system.

BACKGROUND

Conventional air conditioning systems may be sold as a single package unit including an air handling unit, or as a split package in which the air handling unit is installed within a premises. Conventional air handling units rely on fans or blowers, such as a forward-curved fan, to circulate air through the air handling unit. Forward-curved fans, however, have limited static efficiency and significant system losses that can arise due to excessive airstream turning during installation. Additionally, the large physical size of the forward-curved fan consumes considerable space within the air handling unit, contributing to an overall increase in the AHU's dimensions.

SUMMARY

Disclosed herein is an air handling unit (AHU) for use with an air conditioning system. The AHU comprises a housing defining the shape of the AHU, through which air is moved; and a heat exchanger is disposed inside the housing. The heat exchanger is configured to facilitate a transfer of heat to and from the air moving through the housing. The AHU further comprises a diagonal-flow fan disposed inside the housing, wherein an air inflow into the fan and/or an air flow path through the fan is substantially axial, aligned along an axis of rotation of the fan, and wherein the AHU has a height-to-width ratio in a range between 1.8 and 2.3.

In one or more embodiments, the fan has a height-to-width ratio in a range between 0.55 and 0.75.

In one or more embodiments, the ratio of height of the fan to an overall height of the AHU is in a range of 0.2 to 0.3.

In one or more embodiments, a gap between an outlet plane of the heat exchanger and an inlet plane of the fan is in a range between 0 and 1 times an inlet diameter of the fan.

In one or more embodiments, an outlet plane of the heat exchanger aligns with an inlet plane of the fan.

In one or more embodiments, at least a portion of an inlet of the fan is disposed within a space between heat exchange slabs associated with the heat exchanger.

In one or more embodiments, an air inlet of the fan is substantially aligned to the air flow path through the housing.

In one or more embodiments, the AHU comprises a supplemental heating device disposed between the fan outlet plane of the fan and the outlet plane of the housing.

In one or more embodiments, the heat exchanger is substantially V-shaped or substantially A-shaped.

In one or more embodiments, shaft power to a motor driving the fan is in a range from 0.1 hp to 0.75 hp.

In one or more embodiments, a rated speed of a rotor associated with the fan is in a range from 1400 RPM to 2500 RPM.

In one or more embodiments, the speed of a motor associated with the fan is controllable from 50% to 120% of a rated speed of the motor.

In one or more embodiments, the fan is driven by a motor equipped with drive electronics which are mounted remotely from the motor or integrated with the motor.

Further described herein is an air handling unit (AHU) for use with an air conditioning system. The AHU comprises a housing defining the shape of the AHU, through which air is moved; a heat exchanger is disposed inside the housing. The heat exchanger is configured to facilitate a transfer of heat to and from the air moving through the housing. The AHU further comprises a diagonal-flow fan disposed inside the housing, wherein an air inflow into the fan and/or an air flow path through the fan is substantially axial, aligned along an axis of rotation of the fan, and wherein the height of the fan is less than width of the fan, and a gap between an outlet plane of the heat exchanger and an inlet plane of the fan is in a range between 0 and 1 times an inlet diameter of the fan.

In one or more embodiments, an air inlet of the fan is substantially aligned to the air flow path through the housing.

In one or more embodiments, a gap between a fan outlet plane of the fan and an outlet plane of the housing is substantially zero.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, features, and techniques of the invention will become more apparent from the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the subject disclosure of this invention and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the subject disclosure and, together with the description, serve to explain the principles of the subject disclosure.

In the drawings, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

FIGS. 1A to 1D illustrate schematic representations depicting various embodiments of an air handling unit, in accordance with one or more embodiments of the invention;

FIGS. 2A and 2B are detailed schematic perspective and sectional views, respectively, of a fan of the air handling unit of FIGS. 1A to 1D, in accordance with one or more embodiments of the invention;

FIG. 3 is a detailed schematic perspective view of an impeller of the fan of FIGS. 2A and 2B, in accordance with one or more embodiments of the invention;

FIG. 4A is a detailed schematic view of a portion of a set of guide vanes of the fan of FIGS. 2A and 2B, in accordance with one or more embodiments of the invention;

FIG. 4B is a schematic sectional view of a guide vane of the set of guide vanes of FIG. 4A, in accordance with one or more embodiments of the invention;

FIG. 5A is a schematic representation of another air handling unit, in accordance with one or more embodiments of the invention; and

FIG. 5B is a schematic representation of another air handling unit, in accordance with one or more embodiments of the invention.

DETAILED DESCRIPTION

The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject disclosure as defined by the appended claims.

Various terms are used herein. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the subject disclosure, the components of this invention described herein may be positioned in any desired orientation. Thus, the use of terms such as “above,” “below,” “upper,” “lower,” “first,” “second” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components.

The use of the term “about” with reference to a numerical value includes ±10% of the numerical value.

Referring to FIGS. 1A to 1D, a schematic sectional representation of an air handling unit (AHU) 100 for use with an air conditioning system (not shown in figures) is shown. The AHU 100 includes a housing 102 having a housing duct (also designated as 102, herein) fluidically coupling an inlet 104 and an outlet 106 of the housing 102. Air is moved through the housing 102 from the inlet 104 to the outlet 106 along a direction 108 of flow of air.

The AHU 100 further includes a heat exchanger 110. The heat exchanger 110 may be disposed within the housing 102 along a direction 108 of the flow of the air, such that the air flowing through the housing 102 further flows through the heat exchanger 110. The heat exchanger 110 is configured to facilitate transfer of heat to and from the air moving through the housing 102. In some embodiments, the heat exchanger 110 may be configured to cool the air moving through the housing 102. In some other embodiments, the heat exchanger 110 may be configured to heat the air moving through the housing 102. In some embodiments, the heat exchanger 110 includes a primary heat exchanger and other heat transfer devices (not shown). In some embodiments, the air handling unit 100 may be a ducted fan coil unit (FCU).

The AHU 100 further includes a fan 120 disposed inside the housing 102. The fan 120 is configured to move the air through the housing 102, from the inlet 104 to the outlet 106. The fan 120 is a diagonal-flow fan disposed inside the housing 102, such that an air inflow into the fan 120 and/or an air flow path through the fan 120 is substantially axial, aligned along an axis of rotation 112 of the fan 120. The fan 120 may have the axis of rotation 112 that is in-line with the direction 108 of flow of the air through the housing 102. In such embodiments, an air inlet of the fan 120 may be substantially aligned to the air flow path through the housing 102.

As a result, the principally axial flow path through the diagonal-flow fan 120 significantly reduces the pressure loss through the AHU 100 because the air does not have to make the 90-degree turns required to pass through as in the case of conventional forward-curved blowers/fans. The reduced losses substantially contribute to the improvements in efficiency of the AHU 100 made possible by the diagonal-flow fan 120.

In one or more embodiments, the fan 120 may be positioned upstream relative to the heat exchanger 110. In some other embodiments, the fan 120 may be positioned downstream relative to the heat exchanger 110. In the illustrated embodiment of FIGS. 1A to 1D, the fan 120 is positioned downstream relative to the heat exchanger 110. Furthermore, in the illustrated embodiment of FIGS. 1A to 1D, the heat exchanger 110 is substantially V-shaped relative to the direction 108 of flow of the air through the housing 102, however, in other embodiments the heat exchanger 110 may have other shapes or configurations as well without any limitations.

In one or more embodiments, the AHU 100 may have a height-to-width ratio in a range between 1.8 and 2.3. In such embodiments, the fan 120 may have a height-to-width ratio in a range between 0.55 and 0.75. This allows the AHU 100 to have a ratio (H1/H2) of height (H1) of the fan to an overall height (H2) of the AHU 100 or housing duct 102 in a range of 0.2 to 0.3. As a result, the fan 120 or fan coil unit (FCU) occupies between 20% and 30% of the overall height of the AHU 100. The detailed construction of the diagonal-flow fan 120 has been described later in conjunction with FIGS. 2A to 4B. It is to be appreciated that the diagonal-flow fan 120 is physically more compact in the height dimension than conventional forward-curved blowers/fans. This reduction in size enables the overall height of the AHU to be reduced when compared with AHUs equipped with conventional forward-curved blowers/fans.

Referring to FIG. 1A, in one or more embodiments, a gap (G1) between an outlet plane P1 of the heat exchanger 110 and an inlet plane P2 of the fan 120 may be in a range between 0 and 1 times an inlet diameter of the fan 120.

Referring to FIG. 1B in one or more embodiments, an outlet plane P1 of the heat exchanger 110 may align with an inlet plane P2 of the fan 120, such that substantially zero gap remains between the fan 120 and the heat exchanger 110. However, in some embodiments, the outlet plane P1 of the heat exchanger 110 may not align with the inlet plane P2 of the fan 120 and a minimal gap remains between the heat exchanger 110 and the fan 120. This minimal or substantially zero gap between the fan 120 and the heat exchanger 110 within the housing 102 enables the overall height (H2) of the AHU to be reduced when compared with conventional AHUs.

Referring to FIGS. 1C and 1D, in one or more embodiments, at least a portion of an inlet of the fan 120 may be disposed within a space between heat exchange slabs associated with the heat exchanger 110, with the remaining portion of the fan 120 outside and downstream of the heat exchanger's outlet plane P1, such that the inlet plane P2 of the fan 120 remains upstream of the heat exchanger's plane P1. This arrangement may further help reduce the overall height (H2) of the AHU when compared with conventional AHUs.

In addition, referring to FIG. 1D, in one or more embodiments, the length of the diffusion section of the AHU 100 i.e., the distance/gap G2 between a fan outlet plane P3 of the fan 120 and an outlet plane P4 of the housing 102 may be kept substantially zero.

In one or more embodiments, the fan 120 is operable by a motor 122. The motor 122 may be a direct-drive motor. The motor 122 may be operable with a continuous or variable speed control. The motor 122 may be communicably coupled to HVAC controls of the air conditioning unit. As the fan 120 rotates, it may pull in air through the inlet 104 and blow the air through the fan 120 and towards the outlet 106 through the housing duct 102.

Further, the motor 122 may be equipped with drive electronics which may be mounted remotely from the motor 122 or integrated with the motor 122. Remotely mounted drive electronics further help to reduce the overall height of the fan 120. In one or more embodiments, the drive electronics may include a power supply unit that may regulate the supply of electrical power to the motor 122 and associated circuitry, ensuring stable voltage and current levels for reliable operation of the motor 122. The power supply unit may enable and regulate the flow of electrical power from a power source associated with the air conditioning unit or the AHU to the fan 120. Further, the drive electronics may include a controller that may regulate the motor's speed and torque using techniques such as but not limited to Pulse Width Modulation (PWM), enabling smooth adjustments of the motor's rated speed. The controller may include one or more processors that may execute control executable instructions or algorithms, and process input and output signals, to control operation of the motor 122. The drive electronics may further include a communication Interface such as but not limited to CAN, UART, or SPI, which may communicably couple the fan to HVAC controls of the air conditioning unit, allowing remote monitoring and control of the motor 122 and fan 120.

In one or more embodiments, the shaft power to the motor 122 driving the fan 120 may be in a range from 0.1 hp to 0.75 hp (horsepower), ensuring flexibility of varying speed and torque. This power range allows the fan 120 to deliver varying air flow speeds and enable the AHU to meet varying HVAC demands. Further, the rated speed of a fan rotor associated with the motor 122 may be in a range from 1400 RPM to 2500 RPM (rotations per minute). Furthermore, the drive electronics associated with the fan 122 may be configured to operate the fan rotor such that speed of the motor 122 may be controllable from 50% to 120% of the rated speed of the motor 122.

In some embodiments, the heat exchanger 110 may further be coupled with a humidifier (not shown) to facilitate the air passing through the heat exchanger 110 to include user-defined levels of moisture.

In some embodiments, the AHU 100 further includes a supplemental heating device (not shown). In some embodiments, the supplemental heating device may be disposed within the housing 102, along the direction 108 of flow of the air, such that the air flowing through the housing 102 flows through the supplemental heating device. In one or more embodiments, the supplemental heating device may be disposed between the fan outlet plane P3 of the fan 120 and the outlet plane P4 of the housing 112. Further, in one or more embodiments, the supplemental heating device may be located downstream of the fan 120 with a radiation shield between the heating device and the fan 120. The supplemental heating device may be configured to heat up the air passing through the housing 102. In some embodiments, the supplemental heating device and the heat exchanger 110 may together be configured to heat up the air and regulate the heated air temperature, respectively, that is flowing through the housing 102.

In some embodiments, the AHU 100 may be configured with flow directional changes such that air entry and exit are configured for up flow and down flow, as applicable to packaged rooftop units. The AHU 100 may further include a packaged rooftop air management system 150 that is communicably coupled to the different components of the AHU 100, including, without limitations, the heat exchanger 110, the supplemental heating device, the fan 120, and the motor 122. The system 150 may be implemented by a controller 152 configured to control operations of the different components of the AHU 100. In some embodiments, the system 150 may be a part of the HVAC controls of the air conditioning system.

Referring to FIGS. 2A and 2B, detailed schematic perspective and sectional views, respectively, of the diagonal-flow fan 120 are shown. Referring now to FIGS. 1 to 2B, the fan 120 includes a diagonal flow impeller 202. The impeller 202 includes a plurality of blades 204 extending therefrom. In some embodiments, the number of impeller blades 204 may be between about 5 and about 11. Referring now to FIGS. 1 to 2B, in some embodiments, the blades 204 may extend from a hub 206 of the impeller 202. Specifically, the impeller 202 may have the axis of rotation 112 that is arranged in-line with the direction 108 of flow of the air through the housing 102. In some embodiments, the impeller 202 assembly may be manufactured using thermoplastics.

The fan 120 further includes a fan shroud 210 extending circumferentially around the impeller 202. The fan shroud 210 is further secured to the plurality of blades 204. The fan 120 further includes a fan inlet casing 212. The fan inlet casing 212 is disposed circumferentially around the fan shroud 210. The fan inlet casing 212 defines a clearance between the fan inlet casing 212 and the fan shroud 210. The clearance may have appropriate upstream and downstream flow control clearances. In some embodiments, the fan inlet casing 212 includes a plurality of casing elements (not shown in figure) extending from a radially inboard surface of the fan inlet casing 212 towards the fan shroud 210, thereby defining a radial element gap. In some embodiments, the plurality of casing elements may extend axially forward of an inlet plane P2 of the fan 120.

An air flow path through the impeller 202 has a mean angle θ that is oriented along a direction divergent from the axis of rotation 112 of the impeller 202, establishing a diagonal air flow path. In some embodiments, the air flow path through the impeller 202 may be oriented diagonally at an angle of between about 30 degrees and about 80 degrees relative to the axis of rotation 112 of the impeller 202. Further, an air inlet of the fan 120 also remains substantially aligned to the air flow path through the housing 102. Accordingly, an air inflow into the impeller 202/fan 120 remains substantially axial, aligned along the axis of rotation 112 of the fan 120. Compared to other commonly used blower technologies, there is greatly reduced turning of the air as it passes through the fan 120. This reduces the pressure loss associated with flow turning in the fan 120.

The fan 120 further includes a set of axial outlet guide vanes 220 disposed downstream of the impeller 202. The set of guide vanes 220 include a plurality of vanes 222 extending radially from a stator hub 224 towards a stator shroud 226. In some embodiments, the set of guide vanes 220 may include between about 13 and 27 guide vanes 222. In some embodiments, the guide vane assembly may be manufactured using thermoplastics. The set of guide vanes 220 is configured to redirect the flow of air exiting the impeller 202, such that the flow of air exiting the impeller 202 is substantially parallel to the axis of rotation 108 of the impeller 202. In one or more embodiments, the axial position of a fan inlet plane P2 is in a range of between −0.2 and about 1.0 times the fan inlet diameter of the coil outlet plane or outlet plane P1 of the heat exchanger 110.

Referring to FIG. 2B, a schematic perspective view of a guide vane 222 is shown. In some embodiments, the guide vanes 222 have an axial sweep 230 in a range of between about 0 degree and about 30 degrees.

FIG. 2B further shows the blade tip channel angle θs, the mean flow path angle θm, and the blade root channel angle θh. The blade tip channel angle θs of a blade 204 of the impeller 202 may be defined as an angle between the axis of rotation 112 of the impeller 202 and a line tangent to the fan shroud surface 210. The mean flow path angle θm may be defined as the mean meridional flow angle. The blade root channel angle θh may be defined as an angle between the axis of rotation 112 of the impeller 202 and a line tangent to the fan hub surface 206.

Furthermore, FIG. 2B depicts a stator hub-to-tip ratio (Rh/Rt). Rh is a radius of the stator hub 224 from the axis of rotation 112 of the impeller 202. Rt is a radius of the stator shroud 226 from the axis of rotation 112 of the impeller 202. In some embodiments, the guide vanes 222 have a hub-to-tip ratio in a range of between about 60% and about 80%.

Referring to FIG. 3, a detailed schematic perspective view of the impeller 202 and the plurality of blades 204 is shown. FIG. 3 depicts impeller blade camber 304. In some embodiments, the impeller blade camber 304 is between about −10 degrees and about −40 degrees.

FIG. 3 further shows the impeller blade lean. Each impeller blade 204 (e.g., impeller blade 204-1) may lean circumferentially and axially. In some embodiments, the impeller blade lean is between about 25 degrees and about 50 degrees.

Referring to FIG. 4A, a detailed schematic view of a portion of the set of guide vanes 220 is shown. The guide vanes 222 may be arranged to include a sweep along one or both of a circumferential and an axial direction. Each of the guide vanes 222 extends from the stator hub 224 to the stator shroud 226. The guide vanes 222 have a circumferential sweep along at least a portion of the guide vane span. In some embodiments, the circumferential sweep of the guide vanes 222 at stator hub 224 end wall is between about 10 degrees and about 30 degrees. In some embodiments, the circumferential sweep of the guide vane 222 at the stator shroud 226 end wall is between about 10 degrees and about 30 degrees.

Referring to FIG. 4B, a schematic sectional view of a guide vane 222 is shown. In some embodiments, the guide vane 222 has an air foil profile. A maximum camber 452 is located on a camber line 454 of the air foil profile, at between about 25% and about 30% of the chord 456 of the guide vane 222.

Referring to FIG. 5A, a schematic representation of an AHU 500 is shown. The AHU 500 of FIG. 5A is substantially similar to the AHU 100 of FIG. 1A. However, the AHU 500 of FIG. 5A may also be substantially similar to the AHU 100 of FIGS. 1B to 1D. Hence, common components between the AHU 500 of FIG. 5A and the AHU 100 of FIGS. 1A to 1D are referenced using the same reference numerals. However, the AHU 500 includes a heat exchanger 510 that is substantially A-shaped relative to the direction 108 of flow of the air through the housing 102.

Referring to FIG. 5B, a schematic representation of an AHU 550 is shown. The AHU 550 of FIG. 5B is substantially similar to the AHU 100 of FIG. 1A. However, the AHU 500 of FIG. 5B may also be substantially similar to the AHU 100 of FIGS. 1B to 1D. Hence, common components between the AHU 550 of FIG. 5B and the AHU 100 of FIG. 1A to 1D are referenced using the same reference numerals. However, the AHU 550 includes a heat exchanger 560 that includes a single slab heat exchanger.

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined by the appended claims. Modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention includes all embodiments falling within the scope of the invention as defined by the appended claims.

In interpreting the specification, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.

Without excluding further possible embodiments, certain example embodiments are summarized in the following clauses:

Clause 1: The air handling unit of any of the preceding clauses, wherein the circumferential sweep of the guide vanes at the stator shroud end wall is between about 10 degrees and about 30 degrees.

Clause 2: The air handling unit of any of the preceding clauses, wherein the guide vanes have an axial sweep in a range of between about 0 degrees and about 30 degrees.

Clause 3: The air handling unit of any of the preceding clauses, wherein the guide vanes have airfoil profiles with a maximum camber located at between about 25% and about 30% of a chord of the guide vanes.

Clause 4: The air handling unit of any of the preceding clauses, wherein the number of guide vanes is between about 13 and about 27.

Clause 5: The air handling unit of any of the preceding clauses, wherein the impeller and guide vane assemblies are manufactured using thermoplastics.

Clause 6: The air handling unit of any of the preceding clauses, wherein the direct-drive motor is digitally communicating with HVAC controls and has continuous speed control.

Clause 7: The air handling unit of any of the preceding clauses, wherein the axial position of the fan inlet plane is in a range of between-0.2 and about 1.0 times the fan inlet diameter of the coil outlet plane.

Clause 8: The air handling unit of any of the preceding clauses, wherein the fan inlet casing comprises a plurality of casing elements extending from a radially inboard surface of the fan inlet casing toward the shroud, and defining a radial element gap.

Clause 9: The air handling unit of any of the preceding clauses, wherein the fan inlet casing comprises a plurality of casing elements extending axially forward of the inlet plane.

Clause 10: The air handling unit of any of the preceding clauses, wherein the outlet guide vanes have a hub-to-tip ratio in a range of between about 60% and about 80%.