HIGH EFFICIENCY SINGLE DUCT TERMINAL UNIT

Abstract

According to various embodiments, a single duct terminal unit includes an air inlet coupled to a casing that allows air to enter the casing, a heat exchanger disposed within the casing and downstream of the inlet relative to airflow entering the casing, a damper disposed downstream of the heat exchanger relative to the airflow entering the casing, the damper controlling airflow through an air outlet, and a control unit in communication with the damper, where the control unit adjusts a positioning of the damper based upon airflow through the air inlet and a requested temperature of airflow through the air outlet.

Claims

1. A single duct terminal unit, comprising: an air inlet coupled to a casing that allows air to enter the casing; a heat exchanger disposed within the casing and downstream of the inlet relative to airflow entering the casing; a damper disposed downstream of the heat exchanger relative to the airflow entering the casing, the damper controlling airflow through an air outlet; and a control unit in communication with the damper, wherein the control unit adjusts a positioning of the damper based upon airflow through the air inlet and a requested temperature of airflow through the air outlet.

2. The single duct terminal unit of claim 1, wherein the air inlet is sized smaller than the air outlet.

3. The single duct terminal unit of claim 2, wherein the air inlet and air outlet comprise a circular cross section.

4. The single duct terminal unit of claim 2, wherein a diameter of the air outlet is approximately 12.5% to 25% larger than a diameter of the air inlet.

5. The single duct terminal unit of claim 1, wherein the air outlet is disposed downstream of the heat exchanger relative to airflow entering the casing.

6. The single duct terminal of claim 1, wherein the air outlet comprises a cylindrical outlet coupled to the casing, and the damper is disposed within the air outlet.

7. The single duct terminal unit of claim 1, further comprising a flow sensor disposed within the air inlet or the casing, the flow sensor communicatively coupled to the control unit and configured to detect airflow through the air inlet.

8. The single duct terminal unit of claim 1, further comprising a temperature sensor disposed within the air inlet, wherein the temperature sensor provides inlet temperature data to the control unit.

9. The single duct terminal unit of claim 1, further comprising an outlet temperature sensor disposed within the air outlet or downstream of the air outlet, wherein the temperature sensor provides outlet temperature data to the control unit.

10. The single duct terminal unit of claim 1, wherein the heat exchanger comprises a plurality of water coils that utilize a fin and tube construction.

11. The single duct terminal unit of claim 1, wherein the control unit adjusts the positioning of the damper in response to a requested temperature from a thermostat associated with an environment receiving airflow from the air outlet.

12. A method comprising: receiving, in a control unit, a requested temperature associated with an environment; determining, in the control unit, a measure of airflow into an air inlet of a single duct terminal unit based on data from an airflow sensor; determining, in the control unit, a temperature of airflow into the air inlet; determining, in the control unit based on the measure of the airflow and the temperature, a setting for a heat exchanger disposed downstream of the air inlet and upstream of a damper; determining, in the control unit based on the measure of the airflow, the temperature, and the setting for the heat exchanger, a damper position of a damper located downstream of the air inlet and the heat exchanger; and causing, by the control unit, the damper to be position at the damper position and the heat exchanger to activate according to the setting for the heat exchanger.

13. The method of claim 12, wherein the damper is positioned within an air outlet of the single duct terminal unit.

14. A method of claim 12, wherein the control unit determines the damper position and the setting for the heat exchanger based on temperature data from a temperature sensor in the air outlet or downstream of the damper.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] So that the manner in which the above recited features of the various embodiments can be understood in detail, a more particular description of the inventive concepts, briefly summarized above, may be had by reference to various embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of the inventive concepts and are therefore not to be considered limiting of scope in any way, and that there are other equally effective embodiments.

[0013] FIG. 1 illustrates a view of a single duct terminal unit, according to various embodiments of the present disclosure.

[0014] FIG. 2 illustrates an alternative orthographic view of the single duct terminal unit, according to various embodiments of the present disclosure.

[0015] FIG. 3 illustrates a partially transparent, cutaway view of the single duct terminal unit, according to various embodiments of the present disclosure.

[0016] FIG. 4 illustrates a view of the single duct terminal unit with the casing removed, according to various embodiments of the present disclosure.

[0017] FIG. 5 illustrates an alternative view of the single duct terminal unit, according to various embodiments of the present disclosure.

[0018] FIG. 6 illustrates a view of the single duct terminal unit with the casing removed, according to various embodiments of the present disclosure.

[0019] FIG. 7 illustrates an a method according to various embodiments of the present disclosure.

[0020] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

DETAILED DESCRIPTION

[0021] In the following description, numerous specific details are set forth to provide a more thorough understanding of the various embodiments. However, it will be apparent to one skilled in the art that the inventive concepts may be practiced without one or more of these specific details.

[0022] FIG. 1 illustrates an orthographic view of a single duct terminal unit 100, according to various embodiments of the disclosure. The single duct terminal unit 100 includes, without limitation, an air inlet 101, a flow sensor 106, a heat exchanger 103, a casing 107, a damper 301 (shown in later figures), an air outlet 105, and a control unit 104. At a high level, the single duct terminal unit 100 moves air through the system in the direction of arrow 102. Specifically, air is directed through the air inlet 101 in which a flow sensor 106 is disposed. The air is then heated by heat exchanger 103 and passes through casing 107. Airflow is then regulated by the damper 301 before exiting via the air outlet 105. The flow sensor 106 and the damper 301 are also connected to control unit 104, which houses electronics that receive data from flow sensor 106 and other sources, such as temperature sensors or thermostats. The electronics in the control unit 104 also control the damper 301. This setup establishes a feedback loop, enabling precise control of the position of the damper 301 based on temperature data processed by the control unit 104.

[0023] The air inlet 101 comprises an inlet through which air enters the single duct terminal unit 100. The air inlet 101 is coupled to ducting (not shown) through which air is supplied to the air inlet 101. In the depicted example, the air inlet 101 is configured as a circular opening and is affixed to a casing 107. In certain embodiments, air is directed into the unit 100 through a duct system that is coupled to the air inlet 101.

[0024] A flow sensor 106, positioned in or near the air inlet 101, is configured to detect the airflow. The flow sensor 106 is able to transmit sensor readings to the control unit 104 via signal tubing, enabling the control unit 104 to determine airflow characteristics based on the sensor output. The flow sensor 106 measures total pressure and static pressure through the single duct terminal unit 100. The difference between these measurements is the velocity pressure signal, which is then used by the control unit 104 to determine the air flow rate through the air inlet 101 and adjust the damper 301 as needed to meet performance requirements. The control of air to the occupied space allows the desired set point temperature in the environment to be maintained. In the embodiment shown, flow sensor 106 is positioned within the air inlet 101. In some embodiments, a temperature sensor can be integrated into the flow sensor 106 or installed within air inlet 101 to provide the control unit 104 with temperature information about incoming air to the single duct terminal unit 100.

[0025] Heat exchanger 103 is installed downstream of the air inlet 101 and upstream of the air outlet 105. Heat exchanger 103 is designed to heat the air flowing through the air inlet 101 and towards the heat exchanger 103. Notably, at this point, the air is not yet subjected to any damping. In one example, the heat exchanger 103 comprises water coils that utilize a fin and tube construction, allowing a water-glycol mixture to be circulated through the coils to transfer heat into the body of the single duct terminal unit 100.

[0026] The control unit 104 houses the necessary circuitry to process both atmospheric temperature and flow sensor readings required to determine the optimal position of the damper 301. The control unit 104 contains the necessary mechanisms to adjust the damper position, thereby controlling the amount of heated air passing through the single duct terminal unit 100. The damper position represents the degree to which the damper is open or closed, i.e., the extent to which airflow is permitted through the air outlet 105. In the event that no air is to flow past the damper, the control unit rotates a rod connected to the damper such that the damper is oriented perpendicular to the airflow, thereby sealing the air passage. The control unit allows maximum airflow by rotating the rod such that the damper is parallel to the direction of airflow. In the case where a variable amount of air is required to control the temperature, the control unit 104 rotates the rod to adjust the damper position to a state ranging from fully open to fully closed. The control unit may utilize various control methods, such as a feedback loop or other control mechanisms (but not limited thereto), to achieve a specified temperature or airflow, wherein the damper is dynamically adjusted as the control unit 104 detects the room temperature approaching the desired temperature. In the illustrated embodiment, a control unit 104 is coupled to the casing 107. The control unit 104 controls whether the heat exchanger 103 heats air entering the air inlet 101 that flows through the single duct terminal unit 100. Control unit 104 also controls the degree to which heat exchanger 103 heats air passing through the unit depending upon the heating needs of a space to which air flows from single duct terminal unit 100. Control unit 104 receives temperature and/or airflow data from flow sensor 106 as well as temperature data from one or more temperature sensors that can be positioned in air outlet 105 or downstream of the air outlet 105. Control unit 104 can also receive a requested temperature from a thermostat control that obtains temperature data from an environment receiving airflow from single duct terminal unit 100 and allows for users to set a requested temperature for the environment.

[0027] The casing 107 provides an exterior shell in which the heat exchanger 103 is installed and through which air flows from the air inlet 101 to the air outlet 105. In some embodiments, the casing 107 is provided with thermal and acoustic insulation to minimize noise generation and reduce undesired heat transfer between the interior of the single duct terminal unit 100 and the exterior environment. Moreover, the casing 107 is designed to be substantially airtight, thereby directing airflow from the air inlet 101 to the air outlet 105, as will be described in greater detail in subsequent figures. The depicted casing 107 has a generally rectangular cross-section, although alternative geometries for both the air inlet 101 and the casing 107 can be employed.

[0028] FIG. 2 shows an opposing side of single duct terminal unit 100 relative to FIG. 1. Specifically, arrow 201 shows the direction of air flow, as it is exhausted by the air outlet 105. The air outlet 105 discharges air that has passed through the single-duct terminal unit 100. The quantity of airflow is partially controlled by the damper 301, which is illustrated in FIG. 3 and further described in the corresponding discussion. The exhausted air from the air outlet 105 can either be released into the room's ambient environment or directed into another duct for further transport to a designated heating area.

[0029] Terminal unit 100 is designed to accommodate a wider range of air inlet and outlet configurations. This is advantageous because manufacturers often provide only specific sizes for these components, limiting flexibility. The illustrated embodiment of the single-duct air terminal unit 100 can accommodate an outlet diameter that is 12.5% to 25% larger than the air inlet diameter. By sizing the air outlet 105 larger than the air inlet 101, the air velocity at the air outlet 105 is reduced compared to the air inlet 101. By upsizing the air outlet 105 relative to the air inlet 101, the air exiting the single duct terminal unit 100 is more thoroughly mixed than in embodiments that have similarly sized inlets and outlets. As air moves more slowly through the unit, the air has more time to mix uniformly, resulting in more homogeneous mix of air as it leaves the system. This slower flow is a direct result of the ratio between the air inlet 101 and the air outlet 105: as the cross-sectional area of the fluid increases at the air outlet 105, the air velocity decreases (per the continuity principle), allowing the air molecules more time to interact and mix together before exiting the system.

[0030] FIG. 3 illustrates a partially transparent orthographic view of a single duct terminal unit 100, according to examples of the present disclosure. In the depicted view, the casing 107 is rendered as partially transparent to reveal the interior of the single duct terminal unit 100. Air entering the air inlet 101 follows the direction indicated by arrow 102, passes through the flow sensor 106, and is subsequently heated by the heat exchanger 103.

[0031] After passing through the heat exchanger 103, airflow is then regulated by the damper 301, which is positioned downstream of the heat exchanger 103. The damper 301 is configured to rotate about an axis, with its rotational position controlled by the control unit 104. The damper 301 is operatively connected to the control unit 104 via a rod whose position is adjusted by the control unit 104, enabling the position of the damper 301 to vary continuously from a fully closed configuration, wherein the damper is oriented substantially perpendicular to the direction of airflow, to a fully open configuration, wherein the damper is aligned parallel to the airflow through the single duct terminal unit 100.

[0032] By positioning the damper 301 downstream of the heat exchanger 103, air flows evenly over the heat exchanger 105 in contrast to prior art configurations where the damper 301 is positioned upstream of the heat exchanger 103. In prior art configurations, the damper deflects the airflow prior to reaching the heat exchanger 103, resulting in uneven distribution of heated air across the surface of the heat exchanger 103, inaccurate temperature measurements, and reduced efficiency in thermal control. The air inlet 101, air outlet 105, and damper 301 are depicted with a circular cross section in one embodiment. One or more of the air inlet 101, air outlet 105, and damper 301 can be implemented with a different cross-sectional shape, such as an elliptical, square, rectangular, or other cross-sectional shape.

[0033] FIG. 4 illustrates an alternative view of a single duct terminal unit 100 with the casing 107 removed, according to various embodiments of the present disclosure. In this view, another perspective of the damper 301 is provided.

[0034] FIG. 5 illustrates a front view of the single duct terminal unit 100, with the flow sensor 106 shown located within the air inlet 101. As shown in the other figures and corresponding descriptions, the flow sensor 106 provides data used by the control unit 104 to calculate the airflow to the unit.

[0035] FIG. 6 illustrates a rear view of the single duct terminal unit 100, showing the damper 301 located within the outlet 105. In this view, the damper 301 is closed, restricting the airflow and controlling the volume of air delivered to the space served by the single duct terminal unit 100.

[0036] FIG. 7 illustrates a method according to various embodiments of the disclosure. The method can be implemented using the single duct terminal unit 100 discussed with reference to FIGS. 1-6. According to one embodiment, the method 700 begins at step 702, where the control unit 104 receives a requested temperature associated with an environment to which single duct terminal unit 100 delivers heated airflow. For example, the environment includes a room to which air outlet 105 of single duct terminal unit 100 is connected via ducting. The requested temperature can be received from a thermostat or another control system that determines whether the single duct terminal unit 100 should deliver heated air to the environment. In one embodiment, control unit 104 receives temperature data associated with an environment, and the control unit 104 determines whether and to what extent single duct terminal unit 100 should deliver heated air to the environment.

[0037] At step 704, control unit 104 determines a measure of airflow into the single duct terminal unit 100 via air inlet 101. The control unit 104 obtains data from flow sensor 106 to determines how much air is flowing into the single duct terminal unit 100. The airflow can be provided by an air handler or another unit tasked with providing airflow to the single duct terminal unit 100 in the HVAC system associated with the environment.

[0038] At step 706, control unit 104 determines a temperature of the airflow into the air inlet 101. Flow sensor 106 can be equipped with a temperature sensor, or a separate temperature sensor can be disposed within or adjacent to air inlet 101. At step 708, control unit 104 determines a setting for heat exchanger 103 that determines to what extent the heat exchanger heats airflow that has entered air inlet 101 and the casing 107. The control unit 104 determines the setting for heat exchanger 103 based on the temperature of the air entering air inlet 101, the volume or velocity of airflow into the air inlet 101, and the requested temperature associated with the environment. At step 710, control unit 104 determines a damper setting for damper 301 based on the heat exchanger setting and the requested or desired temperature in the environment to which single duct terminal unit 100 is configured to deliver heated airflow. As noted above, the damper 301 is downstream of the heat exchanger 103, which is downstream of the air inlet 101. In some embodiments, damper 301 is disposed within or integrated within air outlet 105.

[0039] In sum, the various embodiments shown and provided herein set forth a high-efficiency single duct terminal unit that addresses the limitations of conventional systems. In one embodiment, the unit incorporates a damper positioned downstream of the heat exchanger to promote uniform airflow over the heating element, thereby enhancing heat transfer and reducing temperature discrepancies. In addition, the unit is designed with an optimized air inlet and outlet configuration, where the outlet diameter exceeds the inlet diameter, to lower airflow velocity and foster more thorough mixing of heated air. These design features collectively yield improved temperature accuracy, more precise control of the heating element, and significant energy savings.

[0040] One technical advantage of the disclosed techniques relative to the prior art is that repositioning a damper downstream of the heat exchanger in a single-duct terminal unit allows for undisturbed and even airflow over the heating element within the unit. By having more uniform airflow to the heating element, the system minimizes the likelihood of overshooting or undershooting the desired temperature, thereby enabling more responsive and finely tuned HVAC control.

[0041] A further technical advantage is that the damper acts as an air mixing element. As noted above, the damper acts as a source of inefficiency in conventional designs for the same reason. However, in the discussed embodiment the damper provides benefit to equipment application, as the mixing element is now downstream of the heat source, the damper creates a more uniform air temperature at the discharge of the product. Better mixing of heated air as it leaves the unit promotes more accurate temperature readings of the air exiting the unit. This means single point temperature sensors will take a more accurate measurement. Improved accuracy of temperature readings yields more precise control of the heating element as well as significant energy savings and lower operational costs.

[0042] A further technical advantage is that disclosed design overcomes the limitations of conventional fixed air inlet-outlet combinations and uneven mixing of heated air within the discharge ductwork. This step increase in size was determined to cause lower velocity air exiting the unit, allowing for a more even mixing of heated air outside the discharge ductwork.

[0043] 1. In some embodiments, a single duct terminal unit comprises an air inlet coupled to a casing that allows air to enter the casing, a heat exchanger disposed within the casing and downstream of the inlet relative to airflow entering the casing, a damper disposed downstream of the heat exchanger relative to the airflow entering the casing, the damper controlling airflow through an air outlet, and a control unit in communication with the damper, wherein the control unit adjusts a positioning of the damper based upon airflow through the air inlet and a requested temperature of airflow through the air outlet.

[0044] 2. The single duct terminal unit of clause 1, wherein the air inlet is sized smaller than the air outlet.

[0045] 3. The single duct terminal unit of clauses 1 or 2, wherein the air inlet and air outlet comprise a circular cross section.

[0046] 4. The single duct terminal unit of any of clauses 1-3, wherein a diameter of the air outlet is approximately 12.5% to 25% larger than a diameter of the air inlet.

[0047] 5. The single duct terminal unit of any of clauses 1-4, wherein the air outlet is disposed downstream of the heat exchanger relative to airflow entering the casing.

[0048] 6. The single duct terminal of any of clauses 1-5, wherein the air outlet comprises a cylindrical outlet coupled to the casing, and the damper is disposed within the air outlet.

[0049] 7. The single duct terminal unit of any of clauses 1-6, further comprising a flow sensor disposed within the air inlet or the casing, the flow sensor communicatively coupled to the control unit and configured to detect airflow through the air inlet.

[0050] 8. The single duct terminal unit of any of clauses 1-7, further comprising a temperature sensor disposed within the air inlet, wherein the temperature sensor provides inlet temperature data to the control unit.

[0051] 9. The single duct terminal unit of any of clauses 1-8, further comprising an outlet temperature sensor disposed within the air outlet or downstream of the air outlet, wherein the temperature sensor provides outlet temperature data to the control unit.

[0052] 10. The single duct terminal unit of any of clauses 1-9, wherein the heat exchanger comprises a plurality of water coils that utilize a fin and tube construction.

[0053] 11. The single duct terminal unit of any of clauses 1-10, wherein the control unit adjusts the positioning of the damper in response to a requested temperature from a thermostat associated with an environment receiving airflow from the air outlet.

[0054] 12. In some embodiments, a method comprises receiving, in a control unit, a requested temperature associated with an environment, determining, in the control unit, a measure of airflow into an air inlet of a single duct terminal unit based on data from an airflow sensor, determining, in the control unit, a temperature of airflow into the air inlet, determining, in the control unit based on the measure of the airflow and the temperature, a setting for a heat exchanger disposed downstream of the air inlet and upstream of a damper, determining, in the control unit based on the measure of the airflow, the temperature, and the setting for the heat exchanger, a damper position of a damper located downstream of the air inlet and the heat exchanger, and causing, by the control unit, the damper to be position at the damper position and the heat exchanger to activate according to the setting for the heat exchanger.

[0055] 13. The method of clause 12, wherein the damper is positioned within an air outlet of the single duct terminal unit.

[0056] 14. In some embodiments, a method of clauses 12 or 13, wherein the control unit determines the damper position and the setting for the heat exchanger based on temperature data from a temperature sensor in the air outlet or downstream of the damper.

[0057] Any and all combinations of any of the claim elements recited in any of the claims and/or any elements described in this application, in any fashion, fall within the contemplated scope of the present invention and protection.

[0058] The descriptions of the various embodiments have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

[0059] Aspects of the present embodiments, such as the control unit, may be embodied as a system, method or computer program product. Accordingly, aspects of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a module, a system, or a computer. In addition, any hardware and/or software technique, process, function, component, engine, module, or system described in the present disclosure may be implemented as a circuit or set of circuits. Furthermore, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.

[0060] Aspects of the present disclosure are described above with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine. The instructions, when executed via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions/acts specified in the flowchart and/or block diagram block or blocks. Such processors may be, without limitation, general purpose processors, special-purpose processors, application-specific processors, or field-programmable gate arrays.

[0061] The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

[0062] While the preceding is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.