Air Handling Unit for Use with an Air Conditioning System

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.

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.

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.

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.

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, a schematic sectional representation of an air handling unit (AHU)for use with an air conditioning system (not shown in figures) is shown. The AHUincludes a housinghaving a housing duct (also designated as, herein) fluidically coupling an inletand an outletof the housing. Air is moved through the housingfrom the inletto the outletalong a directionof flow of air.

The AHUfurther includes a heat exchanger. The heat exchangermay be disposed within the housingalong a directionof the flow of the air, such that the air flowing through the housingfurther flows through the heat exchanger. The heat exchangeris configured to facilitate transfer of heat to and from the air moving through the housing. In some embodiments, the heat exchangermay be configured to cool the air moving through the housing. In some other embodiments, the heat exchangermay be configured to heat the air moving through the housing. In some embodiments, the heat exchangerincludes a primary heat exchanger and other heat transfer devices (not shown). In some embodiments, the air handling unitmay be a ducted fan coil unit (FCU).

The AHUfurther includes a fandisposed inside the housing. The fanis configured to move the air through the housing, from the inletto the outlet. The fanis a diagonal-flow fan disposed inside the housing, such that an air inflow into the fanand/or an air flow path through the fanis substantially axial, aligned along an axis of rotationof the fan. The fanmay have the axis of rotationthat is in-line with the directionof flow of the air through the housing. In such embodiments, an air inlet of the fanmay be substantially aligned to the air flow path through the housing.

As a result, the principally axial flow path through the diagonal-flow fansignificantly reduces the pressure loss through the AHUbecause 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 AHUmade possible by the diagonal-flow fan.

In one or more embodiments, the fanmay be positioned upstream relative to the heat exchanger. In some other embodiments, the fanmay be positioned downstream relative to the heat exchanger. In the illustrated embodiment of, the fanis positioned downstream relative to the heat exchanger. Furthermore, in the illustrated embodiment of, the heat exchangeris substantially V-shaped relative to the directionof flow of the air through the housing, however, in other embodiments the heat exchangermay have other shapes or configurations as well without any limitations.

In one or more embodiments, the AHUmay have a height-to-width ratio in a range between 1.8 and 2.3. In such embodiments, the fanmay have a height-to-width ratio in a range between 0.55 and 0.75. This allows the AHUto have a ratio (H/H) of height (H) of the fan to an overall height (H) of the AHUor housing ductin a range of 0.2 to 0.3. As a result, the fanor fan coil unit (FCU) occupies between 20% and 30% of the overall height of the AHU. The detailed construction of the diagonal-flow fanhas been described later in conjunction with. It is to be appreciated that the diagonal-flow fanis 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, in one or more embodiments, a gap (G) between an outlet plane Pof the heat exchangerand an inlet plane Pof the fanmay be in a range between 0 and 1 times an inlet diameter of the fan.

Referring toin one or more embodiments, an outlet plane Pof the heat exchangermay align with an inlet plane Pof the fan, such that substantially zero gap remains between the fanand the heat exchanger. However, in some embodiments, the outlet plane Pof the heat exchangermay not align with the inlet plane Pof the fanand a minimal gap remains between the heat exchangerand the fan. This minimal or substantially zero gap between the fanand the heat exchangerwithin the housingenables the overall height (H) of the AHU to be reduced when compared with conventional AHUs.

Referring to, in one or more embodiments, at least a portion of an inlet of the fanmay be disposed within a space between heat exchange slabs associated with the heat exchanger, with the remaining portion of the fanoutside and downstream of the heat exchanger's outlet plane P, such that the inlet plane Pof the fanremains upstream of the heat exchanger's plane P. This arrangement may further help reduce the overall height (H) of the AHU when compared with conventional AHUs.

In addition, referring to, in one or more embodiments, the length of the diffusion section of the AHUi.e., the distance/gap Gbetween a fan outlet plane Pof the fanand an outlet plane Pof the housingmay be kept substantially zero.

In one or more embodiments, the fanis operable by a motor. The motormay be a direct-drive motor. The motormay be operable with a continuous or variable speed control. The motormay be communicably coupled to HVAC controls of the air conditioning unit. As the fanrotates, it may pull in air through the inletand blow the air through the fanand towards the outletthrough the housing duct.

Further, the motormay be equipped with drive electronics which may be mounted remotely from the motoror integrated with the motor. Remotely mounted drive electronics further help to reduce the overall height of the fan. In one or more embodiments, the drive electronics may include a power supply unit that may regulate the supply of electrical power to the motorand associated circuitry, ensuring stable voltage and current levels for reliable operation of the motor. 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. 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. 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 motorand fan.

In one or more embodiments, the shaft power to the motordriving the fanmay 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 fanto 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 motormay be in a range from 1400 RPM to 2500 RPM (rotations per minute). Furthermore, the drive electronics associated with the fanmay be configured to operate the fan rotor such that speed of the motormay be controllable from 50% to 120% of the rated speed of the motor.

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

In some embodiments, the AHUfurther includes a supplemental heating device (not shown). In some embodiments, the supplemental heating device may be disposed within the housing, along the directionof flow of the air, such that the air flowing through the housingflows through the supplemental heating device. In one or more embodiments, the supplemental heating device may be disposed between the fan outlet plane Pof the fanand the outlet plane Pof the housing. Further, in one or more embodiments, the supplemental heating device may be located downstream of the fanwith a radiation shield between the heating device and the fan. The supplemental heating device may be configured to heat up the air passing through the housing. In some embodiments, the supplemental heating device and the heat exchangermay together be configured to heat up the air and regulate the heated air temperature, respectively, that is flowing through the housing.

In some embodiments, the AHUmay 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 AHUmay further include a packaged rooftop air management systemthat is communicably coupled to the different components of the AHU, including, without limitations, the heat exchanger, the supplemental heating device, the fan, and the motor. The systemmay be implemented by a controllerconfigured to control operations of the different components of the AHU. In some embodiments, the systemmay be a part of the HVAC controls of the air conditioning system.

Referring to, detailed schematic perspective and sectional views, respectively, of the diagonal-flow fanare shown. Referring now to, the fanincludes a diagonal flow impeller. The impellerincludes a plurality of bladesextending therefrom. In some embodiments, the number of impeller bladesmay be between about 5 and about 11. Referring now to, in some embodiments, the bladesmay extend from a hubof the impeller. Specifically, the impellermay have the axis of rotationthat is arranged in-line with the directionof flow of the air through the housing. In some embodiments, the impellerassembly may be manufactured using thermoplastics.

The fanfurther includes a fan shroudextending circumferentially around the impeller. The fan shroudis further secured to the plurality of blades. The fanfurther includes a fan inlet casing. The fan inlet casingis disposed circumferentially around the fan shroud. The fan inlet casingdefines a clearance between the fan inlet casingand the fan shroud. The clearance may have appropriate upstream and downstream flow control clearances. In some embodiments, the fan inlet casingincludes a plurality of casing elements (not shown in figure) extending from a radially inboard surface of the fan inlet casingtowards the fan shroud, thereby defining a radial element gap. In some embodiments, the plurality of casing elements may extend axially forward of an inlet plane Pof the fan.

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

The fanfurther includes a set of axial outlet guide vanesdisposed downstream of the impeller. The set of guide vanesinclude a plurality of vanesextending radially from a stator hubtowards a stator shroud. In some embodiments, the set of guide vanesmay include between about 13 and 27 guide vanes. In some embodiments, the guide vane assembly may be manufactured using thermoplastics. The set of guide vanesis configured to redirect the flow of air exiting the impeller, such that the flow of air exiting the impelleris substantially parallel to the axis of rotationof the impeller. In one or more embodiments, the axial position of a fan inlet plane Pis in a range of between −0.2 and about 1.0 times the fan inlet diameter of the coil outlet plane or outlet plane Pof the heat exchanger.

Referring to, a schematic perspective view of a guide vaneis shown. In some embodiments, the guide vaneshave an axial sweepin a range of between about 0 degree and about 30 degrees.

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 bladeof the impellermay be defined as an angle between the axis of rotationof the impellerand a line tangent to the fan shroud surface. 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 rotationof the impellerand a line tangent to the fan hub surface.

Furthermore,depicts a stator hub-to-tip ratio (Rh/Rt). Rh is a radius of the stator hubfrom the axis of rotationof the impeller. Rt is a radius of the stator shroudfrom the axis of rotationof the impeller. In some embodiments, the guide vaneshave a hub-to-tip ratio in a range of between about 60% and about 80%.

Referring to, a detailed schematic perspective view of the impellerand the plurality of bladesis shown.depicts impeller blade camber. In some embodiments, the impeller blade camberis between about −10 degrees and about −40 degrees.

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

Referring to, a detailed schematic view of a portion of the set of guide vanesis shown. The guide vanesmay be arranged to include a sweep along one or both of a circumferential and an axial direction. Each of the guide vanesextends from the stator hubto the stator shroud. The guide vaneshave a circumferential sweep along at least a portion of the guide vane span. In some embodiments, the circumferential sweep of the guide vanesat stator hubend wall is between about 10 degrees and about 30 degrees. In some embodiments, the circumferential sweep of the guide vaneat the stator shroudend wall is between about 10 degrees and about 30 degrees.