COLLAPSIBLE COAXIAL FLEX DUCT

Abstract

A heating, ventilation, and air conditioning (HVAC) system for a structure having at least one area to be conditioned includes a blower configured to force an airflow through the HVAC system and a duct assembly in airflow communication with the blower. The duct assembly includes a first duct defining a flow path for a first fluid having a first temperature and a second duct having a hollow interior defining a flow path for a second fluid having a second temperature different from the first temperature. The first duct is arranged within the hollow interior of the second duct such that heat is transferred between the first fluid and the second fluid. At least one of the first duct and the second duct is formed from a collapsible material.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/306,357, filed Feb. 3, 2022, the contents of which are incorporated by reference herein in their entirety.

BACKGROUND

Embodiments of the present disclosure relate to a heating, ventilation, and air conditioning (HVAC) system, and more particularly, to system for balancing an air intake and exhaust of an HVAC system.

HVAC systems are used to provide heating, cooling and/or ventilation to buildings. As buildings become more insulated due to energy efficiency demands, introduction of fresh, outdoor air into the HVAC system is required. Existing systems typically have a single air inlet duct and a single air outlet or exhaust duct located remotely from the inlet duct. Such a system is not balanced and is not energy efficient. Energy recovery ventilators, which can be used to balance a system and exhaust are not typically installed due to high cost. There is therefore a need for a low cost solution to improve the balance and energy efficiency of HVAC systems.

BRIEF DESCRIPTION

According to an embodiment, a heating, ventilation, and air conditioning (HVAC) system for a structure having at least one area to be conditioned includes a blower configured to force an airflow through the HVAC system and a duct assembly in airflow communication with the blower. The duct assembly includes a first duct defining a flow path for a first fluid having a first temperature and a second duct having a hollow interior defining a flow path for a second fluid having a second temperature different from the first temperature. The first duct is arranged within the hollow interior of the second duct such that heat is transferred between the first fluid and the second fluid. At least one of the first duct and the second duct is formed from a collapsible material.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the first duct and the second duct are arranged concentrically.

In addition to one or more of the features described herein, or as an alternative, in further embodiments comprising at least one mounting bracket arranged within the hollow interior to mount the first duct within the second duct.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the at least one mounting bracket is formed from a spring steel.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the at least one mounting bracket is configured to allow a flow of air therethrough.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the at least one mounting bracket has a spiral-like configuration extending over an axial length of the first duct and the second duct.

In addition to one or more of the features described herein, or as an alternative, in further embodiments one of the first fluid and the second fluid is outside air and one of the first fluid and the second fluid is exhaust air.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the first duct has a water-permeable membrane such that water or water vapor is transferrable between the first fluid and the second fluid.

In addition to one or more of the features described herein, or as an alternative, in further embodiments comprising a drain feature associated with at least one of the first duct and the second duct.

In addition to one or more of the features described herein, or as an alternative, in further embodiments at least one of the first duct and the second duct has a vertical orientation to drain water or water vapor that has accumulated therein.

In addition to one or more of the features described herein, or as an alternative, in further embodiments at least one of the first duct and the second duct comprises a plurality of connected duct portions.

In addition to one or more of the features described herein, or as an alternative, in further embodiments comprising a coil unit including a heat exchanger, wherein the first duct is coupled to the coil unit and to an inlet opening arranged at an exterior of the structure.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the heat exchanger is an evaporator.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the coil unit includes a furnace, and the second fluid includes a mixture of air output from the at least one area to be conditioned and flue gas output from the furnace.

In addition to one or more of the features described herein, or as an alternative, in further embodiments comprising a pressure sensor and a movement mechanism arranged within a nested portion of one of the first duct and the second duct.

In addition to one or more of the features described herein, or as an alternative, in further embodiments operation of the movement mechanism is adjustable in response to the pressure sensor to balance a flow within the first duct and the second duct.

According to an embodiment, a duct assembly for a heating, ventilation, and air conditioning (HVAC) system, the duct assembly includes a first duct defining a flow path for a first fluid having a first temperature and a second duct having a hollow interior defining a flow path for a second fluid having a second temperature different from the first temperature. The first duct is arranged within the hollow interior of the second duct such that heat is transferred between the first fluid and the second fluid. At least one of the first duct and the second duct is formed from a collapsible material.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the first duct and the second duct are arranged concentrically.

In addition to one or more of the features described herein, or as an alternative, in further embodiments comprising at least one mounting bracket arranged within the hollow interior to mount the first duct within the second duct.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the first duct has a water-permeable membrane such that water or water vapor is transferrable between the first fluid and the second fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 is a schematic diagram of an exemplary heating, ventilation, and air conditioning (HVAC) system according to an embodiment;

FIG. 2 is a perspective view of a nested portion of an inlet duct and an exhaust duct of an HVAC system according to an embodiment;

FIG. 3 is an end view of a nested portion of an inlet duct and an exhaust duct of an HVAC system according to an embodiment; and

FIG. 4 is a schematic diagram of a nested portion of an inlet duct and an exhaust duct of an HVAC system according to an embodiment.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

Referring now to FIG. 1, an exemplary heating, ventilation, and air conditioning (HVAC) system 20 configured to provide a conditioned air flow to at least one area to be conditioned 22 is illustrated. As shown, the HVAC system 20 includes an intake or inlet duct 24 through which a first fluid, such as fresh, outside air, is provided to the HVAC system 20 via an inlet opening 25. The inlet duct 24 may extend through a wall 26 of the building or structure containing the one or more areas to be conditioned 22. All or at least a portion of the fresh air from the inlet duct 24 is delivered to a mixing unit 28 via operation of an outside air damper 30. The mixing unit 28 may alternatively or additionally be configured to receive a supply or return air RA from one the one or more areas to be conditioned, such as via return air damper 32 coupled to a return air duct 34 extending between the at least one area to be conditioned 22 mixing unit 28 for example.

The air output from the mixing unit 28 is delivered to one or more coil units 36. As shown, the coil unit 36 includes a movement mechanism 38, such as a variable speed fan or blower for example. The movement mechanism 38 is configured to move the resulting supply air output from the mixing unit 28, which may be fresh air or mixture of fresh air and return air, to a heat exchanger 40, such as an evaporator for example, in amounts determined by the speed of the movement mechanism 38.

Although the movement mechanism 38 is shown as being located downstream from the heat exchanger 40, and therefore has a draw-through configuration, it should be understood that embodiments where the movement mechanism 38 is arranged at another located and/or has a blow-through configuration are also within the scope of the disclosure. In the illustrated, non-limiting embodiment, an auxiliary heater 42 is arranged downstream from the heat exchanger 40 and is configured to heat the supply air. However, it should be understood that in embodiments including an auxiliary heater, the auxiliary heater 42 may be arranged at another location, such as upstream from one or both of the heat exchanger 40 and the movement mechanism 36 based on the specific design requirements of the application. Further, the auxiliary heater 42 may be located remotely from the coil unit 36.

Downstream from the coil unit 36, a supply duct 44 extends to and fluidly connects with the one or more areas to be conditioned 22 by the HVAC system 20. From the area to be conditioned 22, a flow of return air RA is provided to the return air duct 34. A portion of the return air RA may, but need not be recirculated to the mixing unit 28 via operation of the return air damper 32 as previously described. The remainder of the return air, also referred to herein as exhaust air EA may be provided to a heat exchanger 46, such as a condenser, before being exhausted to the ambient atmosphere exterior of the structure via the wall 26. In an embodiment, an exhaust movement mechanism 48 is configured to move the flow of the exhaust air EA across the condenser 46 and through the exhaust duct 50 extending from the condenser to the air outlet 52.

It should be understood that the ducts illustrated and described herein may be formed from a single ducts, or alternatively, form a plurality of duct portions having any suitable configuration connected together. Additionally, it should be understood that the HVAC system 20 illustrated and described herein is intended as an example only, and that an HVAC system 20 having another configuration is also within the scope of the disclosure. For example, in embodiments where the coil unit 36 includes a furnace, a portion of the outside air OA provided to the HVAC system 20 via the inlet duct 24 may be diverted to the burners of the furnace. Alternatively, or in addition, in embodiments the exhaust air EA within the exhaust duct 50 may include the flue gas output from the heat exchanger of the furnace.

In the illustrated, non-limiting embodiment, at least a portion of the inlet duct 24 is nested with the exhaust duct 50 is nested. Although the diameter of the inlet duct 24 is illustrated as being smaller in diameter than the exhaust duct 50, and therefore the inlet duct 24 is arranged within the hollow interior of the exhaust duct 50 50, in other embodiments, the exhaust duct 50 may be arranged within the interior of the inlet duct 24. As shown, the inlet duct 24 and the exhaust duct 50 are mounted concentrically about a longitudinal axis; however, embodiments where the ducts 24, 50 are skewed relative to one another or arranged in another suitable configuration are also contemplated herein.

With reference now to FIGS. 2 and 3, an example of a first duct 60 nested within the interior 62 of a second duct 64, representative of the inlet duct and outlet duct is shown in FIG. 2. It should be understood that the first duct 60 and the second duct 62, in combination, may be referred to herein as a duct assembly. An interior 65 of the first duct 60 defines a flow path for a first fluid, and the interior of the second duct 64 defines a flow path for a second fluid. The ends of the first and second duct 60, 64 may be configured to couple via hose clamps or another connector to standard fittings designed to mount to a wall or duct. In another embodiment, an end fitting is pre-attached to one of the ducts 60, 64 prior to installation within the HVAC system 20. Alternatively, an end fitting for both the first and second ducts could be pre-attached to one another to facilitate installation into the HVAC system 20. The end fitting for the first duct may be configured to rotate relative to the end fitting for the second duct or vice versa to lock the end fitting into position.

The first duct 60 is mounted within the interior 62 of the second duct 64 via one or more mounting brackets 66. A mounting bracket 66 that is capable of maintaining the relative position of the ducts 60, 64 without impeding the flow in the second duct 64 is contemplated herein. An example of a mounting bracket 66 is best shown in FIG. 3. As shown, the mounting bracket 66 may be generally star shaped, thereby defining a plurality of points of contact with both the interior surface of the second duct 64 and the exterior surface of the first duct 60. The star shaped bracket 66 may be arranged within a plane, or alternatively, may wrap in a spiral-like configuration extending over an axial length of all or at least a portion of the first and second ducts 60, 64. The at least one mounting bracket 66 may be formed from any material, including a spring steel wire, and a resilient plastic for example.

At least one of the first duct 60 and the second duct 64 is formed from a flexible or collapsible material, such as a coiled hose. In an embodiment, both the first duct 60 and the second duct 64 are formed form a collapsible material.

The nested portions of the first and second ducts 60, 64 are configured to function like a heat exchanger to transfer thermal energy between the fresh, outside air OA and the exhaust air EA. For example, as the exhaust air EA passes through the portion of the exhaust duct 50 nested with a portion of the inlet duct 24, heat is transferred from the exhaust air EA to the fresh outside air OA.

In the illustrated, non-limiting embodiment, the first duct 60, regardless of whether it functions as the inlet duct 24 or the exhaust duct 50, includes a moisture or water-permeable membrane that allows humidity, such as in the form of water or water vapor for example, to be transferred between the fresh outside air OA and the exhaust air EA. The water-permeable membrane may be formed from a suitable polymeric material, such as an ionomer known as Nafion®, which is a sulfonated tetrafluoroethylene based fluoropolymer-copolymer. Features of Nafion® include high temperature-endurance (up to 190° C.), chemical resistance, and water permeability based on temperature and pressure. In an embodiment, the entire length of the first duct 60 is made of the water-permeable material for simplicity of design and manufacturing. In other embodiments, only a portion of the first duct 60, such as the portion that is nested within the second duct 64 for example, is made of the water-permeable material. Furthermore, embodiments where neither the first duct 60 nor the second duct 64 includes a water-permeable membrane are also contemplated herein.

In embodiments where one of the first duct 60 and the second duct 64 includes a water-permeable membrane, the duct configured to receive the moisture or condensation therein may be configured such that the condensation is drained therefrom. In an embodiment, the duct may have one or more have one or more drain features formed therein to drain condensation collected within the duct. Alternatively, or in addition, the overlapping ducts 60, 64 may have a vertical orientation such that any water accumulated within either duct is configured to fall via gravity to the lowermost end thereof.

With reference now to FIG. 4, in an embodiment, a control system including a controller C may be operable to balance the flows between the inlet duct 24 and the exhaust duct 50. Flow balancing may be accomplished using any suitable flow sensing method. Examples of suitable flow sensing methods include, but are not limited to the use of resistance temperature detector (RTD) flow sensors, pressure sensors, blower or motor torque, and blower or motor rotational speed.

In the illustrated, non-limiting embodiment, the control system includes at least one pressure sensor S for sensing the flow and at least one movement mechanism or blower 68. Although the pressure sensor S and movement mechanism 68 are shown as being mounted within the inlet duct 24, embodiments where they are alternatively or additionally arranged within the exhaust duct 50 or within another suitable portion of the system are also contemplated herein. The pressure sensor S is configured to monitor a pressure within the duct, and operation of the movement mechanism 68 may be controlled in response to the pressure measured by the pressure sensor S. For example, the controller C is configured to adjust the speed of the movement mechanism 68 such that the pressure being measured is substantially equal to the pressure within the other of the inlet duct 24 and exhaust duct 50. Balancing the pressure within the inlet duct 24 and the exhaust duct 50 will ensure that the flow of outside air OA into the system 20 is substantially equal to the flow of exhaust air EA exhausted from the system 20.

The nested portion of the inlet duct 24 and the exhaust duct 50 as described herein is quick and easy to install and provides a low-cost balanced HVAC system. Further, because the nested portions of the inlet duct 24 and the exhaust duct 50 are collapsible, the space required to store these components on a warehouse shelf or in a work truck is limited.

The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.

While the present disclosure has been described with reference to an exemplary embodiment or 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 present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.

Claims

1. A heating, ventilation, and air conditioning (HVAC) system for a structure having at least one area to be conditioned comprising:

a blower configured to force an airflow through the HVAC system; and

a duct assembly in airflow communication with the blower, the duct assembly comprising: a first duct defining a flow path for a first fluid having a first temperature; and a second duct having a hollow interior defining a flow path for a second fluid having a second temperature different from the first temperature, the first duct being arranged within the hollow interior of the second duct such that heat is transferred between the first fluid and the second fluid; wherein at least one of the first duct and the second duct is formed from a collapsible material.

2. The HVAC system of claim 1, wherein the first duct and the second duct are arranged concentrically.

3. The HVAC system of claim 1, further comprising at least one mounting bracket arranged within the hollow interior to mount the first duct within the second duct.

4. The HVAC system of claim 3, wherein the at least one mounting bracket is formed from a spring steel.

5. The HVAC system of claim 3, wherein the at least one mounting bracket is configured to allow a flow of air therethrough.

6. The HVAC system of claim 3, wherein the at least one mounting bracket has a spiral-like configuration extending over an axial length of the first duct and the second duct.

7. The HVAC system of claim 3, wherein one of the first fluid and the second fluid is outside air and one of the first fluid and the second fluid is exhaust air.

8. The HVAC system of claim 1, wherein the first duct has a water-permeable membrane such that water or water vapor is transferrable between the first fluid and the second fluid.

9. The HVAC system of claim 8, further comprising a drain feature associated with at least one of the first duct and the second duct.

10. The HVAC system of claim 8, wherein at least one of the first duct and the second duct has a vertical orientation to drain water or water vapor that has accumulated therein.

11. The HVAC system of claim 1, wherein at least one of the first duct and the second duct comprises a plurality of connected duct portions.

12. The HVAC system of claim 1, further comprising

a coil unit including a heat exchanger, wherein the first duct is coupled to the coil unit and to an inlet opening arranged at an exterior of the structure.

13. The HVAC system of claim 12, wherein the heat exchanger is an evaporator.

14. The HVAC system of claim 12, wherein the coil unit includes a furnace, and the second fluid includes a mixture of air output from the at least one area to be conditioned and flue gas output from the furnace.

15. The HVAC system of claim 1, further comprising a pressure sensor and a movement mechanism arranged within a nested portion of one of the first duct and the second duct.

16. The HVAC system of claim 15, wherein operation of the movement mechanism is adjustable in response to the pressure sensor to balance a flow within the first duct and the second duct.

17. A duct assembly for a heating, ventilation, and air conditioning (HVAC) system, the duct assembly comprising:

a first duct defining a flow path for a first fluid having a first temperature; and

a second duct having a hollow interior defining a flow path for a second fluid having a second temperature different from the first temperature, the first duct being arranged within the hollow interior of the second duct such that heat is transferred between the first fluid and the second fluid;

wherein at least one of the first duct and the second duct is formed from a collapsible material.

18. The duct assembly of claim 17, wherein the first duct and the second duct are arranged concentrically.

19. The duct assembly of claim 17, further comprising at least one mounting bracket arranged within the hollow interior to mount the first duct within the second duct.

20. The duct assembly of claim 17, wherein the first duct has a water-permeable membrane such that water or water vapor is transferrable between the first fluid and the second fluid.