CONDENSATE MANAGEMENT SYSTEM FOR AN AIR CONDITIONER APPLIANCE

Abstract

An air conditioner unit includes a bulkhead mounted within a cabinet to define an indoor portion and an outdoor portion, an indoor heat exchanger positioned within the indoor portion, an outdoor heat exchanger positioned within the outdoor portion, a base pan positioned under the outdoor heat exchanger for collecting condensate that drips off the outdoor heat exchanger, a wall sleeve defining a mechanical compartment configured for receiving at least a portion of the base pan, the indoor heat exchanger, and the outdoor heat exchanger, and a defrost heater mounted within a gap defined between the base pan and the wall sleeve.

Claims

1. An air conditioner unit defining a vertical, a lateral, and a transverse direction, the air conditioner unit comprising: a bulkhead mounted within a cabinet to define an indoor portion and an outdoor portion; an indoor heat exchanger positioned within the indoor portion; an outdoor heat exchanger positioned within the outdoor portion; a base pan positioned under the outdoor heat exchanger for collecting condensate that drips off the outdoor heat exchanger; a wall sleeve defining a mechanical compartment configured for receiving at least a portion of the base pan, the indoor heat exchanger, and the outdoor heat exchanger; and a defrost heater mounted within a gap defined between the base pan and the wall sleeve.

2. The air conditioner unit of claim 1, wherein the defrost heater is mounted to a bottom of the base pan.

3. The air conditioner unit of claim 1, wherein the defrost heater is mounted to the wall sleeve.

4. The air conditioner unit of claim 1, wherein the defrost heater is mounted proximate a pan hole.

5. The air conditioner unit of claim 4, wherein the defrost heater surrounds the pan hole.

6. The air conditioner unit of claim 1, wherein the defrost heater extends to a discharge port defined on the wall sleeve.

7. The air conditioner unit of claim 1, wherein the defrost heater defines cutouts or channels for guiding the condensate out of the wall sleeve.

8. The air conditioner unit of claim 1, wherein the defrost heater is a resistive heater.

9. The air conditioner unit of claim 1, further comprising an ambient temperature sensor and a controller in operative communication with the ambient temperature sensor, the controller being configured to: determine that a defrost cycle is requested; obtain an ambient temperature using the ambient temperature sensor; determine that the ambient temperature is below a predetermined temperature threshold; and activate the defrost heater and perform the defrost cycle.

10. The air conditioner unit of claim 9, wherein the controller is further configured to: determine that the ambient temperature is at or above the predetermined temperature threshold; and deactivate the defrost heater.

11. The air conditioner unit of claim 9, wherein the predetermined temperature threshold is 32 F.

12. The air conditioner unit of claim 9, wherein the controller is further configured to: determine the defrost cycle is not being performed; and stop operating the defrost heater.

13. A condensate management system for an air conditioner unit, the air conditioner unit comprising a bulkhead mounted within a cabinet to define an indoor portion and an outdoor portion, an indoor heat exchanger positioned within the indoor portion, and an outdoor heat exchanger positioned within the outdoor portion, the condensate management system comprising: a base pan positioned under the outdoor heat exchanger for collecting condensate that drips off the outdoor heat exchanger; a wall sleeve defining a mechanical compartment configured for receiving at least a portion of the base pan, the indoor heat exchanger, and the outdoor heat exchanger; and a defrost heater mounted within a gap defined between the base pan and the wall sleeve.

14. The condensate management system of claim 13, wherein the defrost heater is mounted to a bottom of the base pan or to the wall sleeve.

15. The condensate management system of claim 13, wherein the defrost heater is mounted proximate a pan hole.

16. The condensate management system of claim 15, wherein the defrost heater surrounds the pan hole.

17. The condensate management system of claim 13, wherein the defrost heater extends to a discharge port defined on the wall sleeve.

18. The condensate management system of claim 13, wherein the defrost heater defines cutouts or channels for guiding the condensate out of the wall sleeve.

19. The condensate management system of claim 13, further comprising an ambient temperature sensor and a controller in operative communication with the ambient temperature sensor, the controller being configured to: determine that a defrost cycle is requested; obtain an ambient temperature using the ambient temperature sensor; determine that the ambient temperature is below a predetermined temperature threshold; and activate the defrost heater and perform the defrost cycle.

20. The condensate management system of claim 19, wherein the controller is further configured to: determine that the ambient temperature is at or above the predetermined temperature threshold; and deactivate the defrost heater.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

[0011] FIG. 1 provides an exploded perspective view of an air conditioner unit according to an example embodiment of the present subject matter.

[0012] FIG. 2 provides a perspective view of a sealed system of the example air conditioner unit of FIG. 1 according to an example embodiment of the present subject matter.

[0013] FIG. 3 provides a schematic view of a sealed system of the example air conditioner unit of FIG. 1 according to an example embodiment of the present subject matter.

[0014] FIG. 4 is a rear perspective view of the example air conditioner unit of FIG. 1 with portions of a wall sleeve removed for clarity according to an example embodiment of the present subject matter.

[0015] FIG. 5 is a bottom perspective view of the example air conditioner unit of FIG. 1 according to an example embodiment of the present subject matter.

[0016] FIG. 6 is a perspective view of a base pan within the wall sleeve of the example air conditioner unit of FIG. 1 according to an example embodiment of the present subject matter.

[0017] FIG. 7 is another perspective view of the base pan within the wall sleeve of the example air conditioner unit of FIG. 1 according to an example embodiment of the present subject matter.

[0018] FIG. 8 is a perspective view of the base pan raised within the wall sleeve of the example air conditioner unit of FIG. 1 according to an example embodiment of the present subject matter.

[0019] FIG. 9 is a top view of the base pan of the example air conditioner unit of FIG. 1 according to an example embodiment of the present subject matter.

[0020] FIG. 10 is a schematic side view of the base pan and the wall sleeve of the example air conditioner unit of FIG. 1 according to an example embodiment of the present subject matter.

[0021] FIG. 11 illustrates a method for operating an air conditioner unit in accordance with an example embodiment of the present disclosure.

[0022] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.

DETAILED DESCRIPTION

[0023] Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0024] As used herein, the terms first, second, and third may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms includes and including are intended to be inclusive in a manner similar to the term comprising. Similarly, the term or is generally intended to be inclusive (i.e., A or B is intended to mean A or B or both). The term at least one of in the context of, e.g., at least one of A, B, and C refers to only A, only B, only C, or any combination of A, B, and C. In addition, here and throughout the specification and claims, range limitations may be combined and/or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The singular forms a, an, and the include plural references unless the context clearly dictates otherwise.

[0025] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as generally, about, approximately, and substantially, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or the precision of the methods or machines for constructing or manufacturing the components and/or systems. For example, the approximating language may refer to being within a 10 percent margin, i.e., including values within ten percent greater or less than the stated value. In this regard, for example, when used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction, e.g., generally vertical includes forming an angle of up to ten degrees in any direction, e.g., clockwise or counterclockwise, with the vertical direction V.

[0026] The word exemplary is used herein to mean serving as an example, instance, or illustration. In addition, references to an embodiment or one embodiment does not necessarily refer to the same embodiment, although it may. Any implementation described herein as exemplary or an embodiment is not necessarily to be construed as preferred or advantageous over other implementations. Moreover, each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0027] FIG. 1 provides an exploded perspective view of a packaged terminal air conditioner unit 100 according to example embodiments of the present disclosure. Generally, packaged terminal air conditioner unit 100 is operable to generate chilled and/or heated air in order to regulate the temperature of an associated room or building. As will be understood by those skilled in the art, packaged terminal air conditioner unit 100 may be utilized in installations where split heat pump systems are inconvenient or impractical. As illustrated, packaged terminal air conditioner unit 100 defines a vertical direction V, a lateral direction L, and a transverse direction T that are mutually perpendicular and form an orthogonal direction system.

[0028] As used herein, the term packaged terminal air conditioner unit is applied broadly, and the present subject matter is not limited to the specific constructions described and illustrated herein. For example, although aspects of the present subject matter are described with reference to PTAC unit 100, it should be appreciated that aspects of the present subject matter may be equally applicable to other air conditioner unit types and configurations, such as single package vertical units (SPVUs) and split heat pump systems.

[0029] As discussed in greater detail below, air conditioner unit 100 may include a sealed system 102 (i.e., sealed heat exchange system) to facilitate heat transfer and conditioning of a room where air conditioner unit 100 is located. Sealed system 102 includes components for transferring heat between the exterior atmosphere and the interior atmosphere, as discussed in greater detail below. In general, air conditioner unit 100 may be a self-contained or autonomous system for heating and/or cooling air.

[0030] According to an example embodiment, sealed system 102 and other components of air conditioner unit 100 may be disposed within a wall sleeve 104 of air conditioner unit 100. In general, wall sleeve 104 may be a structural frame that extends between an interior side portion 106 and an exterior side portion 108. Interior side portion 106 of wall sleeve 104 and exterior side portion 108 of wall sleeve 104 are spaced apart from each other along the transverse direction T. Thus, interior side portion 106 of wall sleeve 104 may be positioned at or contiguous with an interior atmosphere of the room being conditioned, and exterior side portion 108 of wall sleeve 104 may be positioned at or contiguous with an exterior atmosphere (e.g., the outside ambient environment).

[0031] As shown, wall sleeve 104 may generally define an internal volume or a mechanical compartment 110. Sealed system 102 is disposed or positioned within mechanical compartment 110 of wall sleeve 104. A front panel 112 and a rear grill or screen 114 hinder or limit access to mechanical compartment 110 of wall sleeve 104. Front panel 112 is positioned at or adjacent interior side portion 106 of wall sleeve 104, and rear screen 114 is mounted to wall sleeve 104 at exterior side portion 108 of wall sleeve 104. Front panel 112 and rear screen 114 each define a plurality of holes that permit air to flow through front panel 112 and rear screen 114, with the holes sized for preventing foreign objects from passing through front panel 112 and rear screen 114 into mechanical compartment 110 of wall sleeve 104.

[0032] Air conditioner unit 100 also includes a drain pan, a bottom tray, or a base pan 120 that sits within wall sleeve 104 and supports various components of sealed system 102 and air conditioner unit 100. As discussed in more detail below, base pan 120 may include various features to facilitate condensate management within air conditioner unit 100. For example, because sealed system 102 is positioned on base pan 120, liquid runoff from sealed system 102 (e.g., collected condensate) may flow into and collect within base pan 120. Air conditioner unit 100 may include additional features to discharge the collected condensate, prevent the collected condensate from freezing, or otherwise effectively manage the collected condensate.

[0033] Air conditioner unit 100 may further include an inner wall or bulkhead 122 positioned within mechanical compartment 110 of wall sleeve 104. Bulkhead 122 may be mounted to base pan 120 and extends upwardly from base pan 120 to a top wall of wall sleeve 104. Bulkhead 122 limits or prevents air flow between interior side portion 106 of wall sleeve 104 and exterior side portion 108 of wall sleeve 104 within mechanical compartment 110 of wall sleeve 104. Thus, bulkhead 122 may divide mechanical compartment 110 of wall sleeve 104. Specifically, bulkhead 122 may generally separate and define an indoor portion 124 and an outdoor portion 126.

[0034] In general, during installation of air conditioner unit 100, wall sleeve 104 is first mounted within an opening defined within a building wall, e.g., using any suitable mechanical fastener, welding, adhesive, etc. In addition, the joint between wall sleeve 104 and the building wall may be sealed using any suitable caulk, sealant, etc. Bulkhead 122, sealed system 102, and other components of air conditioner unit 100 are then mounted at least partially within wall sleeve 104. Wall sleeve 104 may generally be constructed of any suitable number of layers and/or materials, e.g., to provide structural rigidity necessary to support components of package terminal air conditioner unit 100 while achieving the desired sound damping. In this regard, for example, wall sleeve 104 may include a stamped metal layer, e.g., formed from stainless steel, painted external steel, or any other suitably rigid material, such as a rigid plastic.

[0035] FIG. 2 provides a perspective view of certain components of air conditioner unit 100, including sealed system 102. In addition, FIG. 3 provides a schematic view of air conditioner unit 100. As shown, sealed system 102 includes a compressor 130, an interior heat exchanger or coil 132 and an exterior heat exchanger or coil 134. As is generally understood, compressor 130 is generally operable to circulate or urge a flow of refrigerant through sealed system 102, which may include various conduits which may be utilized to flow refrigerant between the various components of sealed system 102. Thus, indoor heat exchanger 132 and outdoor heat exchanger 134 may be between and in fluid communication with each other and compressor 130.

[0036] As will be described in further detail below, sealed system 102 may operate in a cooling mode and, alternately, a heating mode. During operation of sealed system 102 in the cooling mode, refrigerant generally flows from indoor heat exchanger 132 and to compressor 130. During operation of sealed system 102 in the heating mode, refrigerant generally flows from outdoor heat exchanger 134 and to compressor 130. As will be explained in more detail below, a reversing valve 136 in fluid communication with compressor 130 may control refrigerant flow to and from compressor 130, as well as the coils 132, 134.

[0037] During operation of sealed system 102 in the cooling mode, refrigerant flows from indoor heat exchanger 132 and to compressor 130. For example, refrigerant may exit indoor heat exchanger 132 as a fluid in the form of a superheated vapor. Upon exiting indoor heat exchanger 132, the refrigerant may enter compressor 130, which is operable to compress the refrigerant. Accordingly, the pressure and temperature of the refrigerant may be increased in compressor 130 such that the refrigerant becomes a more superheated vapor.

[0038] Outdoor heat exchanger 134 is disposed downstream of compressor 130 in the cooling mode and acts as a condenser. Thus, outdoor heat exchanger 134 is operable to reject heat into the exterior atmosphere at exterior side portion 108 of wall sleeve 104 when sealed system 102 is operating in the cooling mode. For example, the superheated vapor from compressor 130 may enter outdoor heat exchanger 134 via a first distribution conduit 138 (FIG. 2) that extends between and fluidly connects reversing valve 136 and outdoor heat exchanger 134. Within outdoor heat exchanger 134, the refrigerant from compressor 130 transfers energy to the exterior atmosphere and condenses into a saturated liquid and/or liquid vapor mixture. An exterior air handler or outdoor fan 140 (FIG. 3) is positioned adjacent outdoor heat exchanger 134 and may facilitate or urge a flow of air from the exterior atmosphere across outdoor heat exchanger 134 in order to facilitate heat transfer.

[0039] According to the illustrated embodiment, an expansion device or a variable electronic expansion valve 142 may be further provided to regulate refrigerant expansion. Specifically, variable electronic expansion valve 142 is disposed along a fluid conduit 144 that extends between indoor heat exchanger 132 and outdoor heat exchanger 134. During use, variable electronic expansion valve 142 may generally expand the refrigerant, lowering the pressure and temperature thereof. In the cooling mode, refrigerant, which may be in the form of high liquid quality/saturated liquid vapor mixture, may exit outdoor heat exchanger 134 and travel through variable electronic expansion valve 142 before flowing through indoor heat exchanger 132. In the heating mode, refrigerant may exit indoor heat exchanger 132 and travel through variable electronic expansion valve 142 before flowing to outdoor heat exchanger 134. As described in more detail below, variable electronic expansion valve 142 is generally configured to be adjustable. In other words, the flow (e.g., volumetric flow rate in milliliters per second) of refrigerant through variable electronic expansion valve 142 may be selectively varied or adjusted.

[0040] Indoor heat exchanger 132 is disposed downstream of variable electronic expansion valve 142 in the cooling mode and acts as an evaporator. Thus, indoor heat exchanger 132 is operable to heat refrigerant within indoor heat exchanger 132 with energy from the interior atmosphere at interior side portion 106 of wall sleeve 104 when sealed system 102 is operating in the cooling mode. For example, the liquid or liquid vapor mixture refrigerant from variable electronic expansion valve 142 may enter indoor heat exchanger 132 via fluid conduit 144. Within indoor heat exchanger 132, the refrigerant from variable electronic expansion valve 142 receives energy from the interior atmosphere and vaporizes into superheated vapor and/or high-quality vapor mixture. An interior air handler or indoor fan 146 (FIG. 3) is positioned adjacent indoor heat exchanger 132 and may facilitate or urge a flow of air from the interior atmosphere across indoor heat exchanger 132 in order to facilitate heat transfer. From indoor heat exchanger 132, refrigerant may return to compressor 130 from reversing valve 136, e.g., via a second conduit 148 (FIG. 2) that extends between and fluidly connects indoor heat exchanger 132 and reversing valve 136.

[0041] During operation of sealed system 102 in the heating mode, reversing valve 136 reverses the direction of refrigerant flow from compressor 130. Thus, in the heating mode, indoor heat exchanger 132 is disposed downstream of compressor 130 and acts as a condenser, e.g., such that indoor heat exchanger 132 is operable to reject heat into the interior atmosphere at interior side portion 106 of wall sleeve 104. In addition, outdoor heat exchanger 134 is disposed downstream of variable electronic expansion valve 142 in the heating mode and acts as an evaporator, e.g., such that outdoor heat exchanger 134 is operable to heat refrigerant within outdoor heat exchanger 134 with energy from the exterior atmosphere at exterior side portion 108 of wall sleeve 104.

[0042] Accordingly, as is understood in the art, sealed system 102 may be alternately operated as a refrigeration assembly (and thus perform a refrigeration cycle) or a heat pump (and thus perform a heat pump cycle). As shown in FIG. 3, when sealed system 102 is operating in a cooling mode and thus performing a refrigeration cycle, the indoor heat exchanger 132 acts as an evaporator and the outdoor heat exchanger 134 acts as a condenser. Alternatively, when the assembly is operating in a heating mode and thus performs a heat pump cycle, the indoor heat exchanger 132 acts as a condenser and the outdoor heat exchanger 134 acts as an evaporator. The outdoor and indoor heat exchangers 132, 134 may each include coils through which a refrigerant may flow for heat exchange purposes, as is generally understood.

[0043] In addition, sealed system 102 may be operated in a defrost mode, e.g., to remove frost from outdoor heat exchanger 134, particularly when the ambient temperature is low. In this regard, in the defrost mode, sealed system 102 is configured to urge hot refrigerant directly into outdoor heat exchanger, e.g., by adjusting the operation of compressor 130 and compressions reversing valve 136. This hot refrigerant causes any frozen condensate on the coils of outdoor heat exchanger to melt and fall off into base pan 120.

[0044] Referring again to FIG. 1, air conditioner unit 100 may additionally include a control panel 160 and one or more user inputs 162, which may be included in control panel 160. A display 164 may additionally be provided in the control panel 160, such as a touchscreen or other text-readable display screen. Alternatively, display 164 may simply be a light that can be activated and deactivated as required to provide an indication of, for example, an event or setting for air conditioner unit 100. The user inputs 162 and/or display 164 may be in communication with the controller 166. A user of air conditioner unit 100 may interact with the user inputs 162 to operate air conditioner unit 100, and user commands may be transmitted between the user inputs 162 and controller 166 to facilitate operation of air conditioner unit 100 based on such user commands.

[0045] Controller 166 may regulate operation of air conditioner unit 100, e.g., responsive to sensed conditions and user input from control panel 160. Thus, controller 166 is operably coupled to various components of air conditioner unit 100, such as control panel 160, components of sealed system 102, and/or a temperature sensor (not shown), such as a thermistor or thermocouple, for measuring the temperature of the interior atmosphere. In particular, controller 166 may selectively activate sealed system 102 in order to chill or heat air within sealed system 102, e.g., in response to temperature measurements from the temperature sensor.

[0046] In some embodiments, controller 166 includes memory and one or more processing devices. For instance, the processing devices may be microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of air conditioner unit 100. The memory can represent random access memory such as DRAM, or read only memory such as ROM or FLASH. The processor executes programming instructions stored in the memory. The memory can be a separate component from the processor or can be included onboard within the processor. Alternatively, controller 166 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.

[0047] In order to facilitate operation of sealed system 102 and other components of air conditioner unit 100, air conditioner unit 100 may include a variety of sensors for detecting conditions internal and external to air conditioner unit 100. These conditions can be fed to controller 166 which may make decisions regarding operation of air conditioner unit 100. For example, as best illustrated in FIG. 3, air conditioner unit 100 may include an ambient temperature and/or humidity sensor 170 which is positioned and configured for measuring the outdoor or ambient temperature and/or humidity. According to exemplary embodiments, air conditioner unit 100 may further include an indoor temperature/humidity sensor for measuring indoor conditions temperatures.

[0048] As used herein, temperature sensor or the equivalent is intended to refer to any suitable type of temperature measuring system or device positioned at any suitable location for measuring the desired temperature. Thus, for example, temperature sensor 170 may each be any suitable type of temperature sensor, such as a thermistor, a thermocouple, a resistance temperature detector, a semiconductor-based integrated circuit temperature sensor, etc. In addition, temperature sensor 170 may be positioned at any suitable location and may output a signal, such as a voltage, to a controller that is proportional to and/or indicative of the temperature being measured. Although exemplary positioning of temperature sensors is described herein, it should be appreciated that air conditioner unit 100 may include any other suitable number, type, and position of temperature, and/or other sensors according to alternative embodiments.

[0049] As used herein, the terms humidity sensor or the equivalent may be intended to refer to any suitable type of humidity measuring system or device positioned at any suitable location for measuring the desired humidity. Thus, for example, humidity sensor 170 may refer to any suitable type of humidity sensor, such as capacitive digital sensors, resistive sensors, and thermal conductivity humidity sensors. In addition, humidity sensor 170 may be positioned at any suitable location and may output a signal, such as a voltage, to a controller that is proportional to and/or indicative of the humidity being measured. Although exemplary positioning of humidity sensors is described herein, it should be appreciated that unit 100 may include any other suitable number, type, and position of humidity sensors according to alternative embodiments.

[0050] Referring now also generally to FIGS. 4 through 9, a water or condensate management system 200 of air conditioner unit 100 will be described according to example embodiments of the present subject matter. In this regard, as explained briefly above, operation of air conditioner unit 100 may generally result in the formation of condensate or water melted off the heat exchanger coils that must be collected, discharged, or otherwise managed in air conditioner unit 100. For example, when air conditioner unit 100 is operating in the heat pump mode, condensate may tend to form on outdoor heat exchanger 134. In addition, during the defrost mode, ice and/or frost may be melted off outdoor heat exchanger 134. This condensate may collect below outdoor heat exchanger 134. Notably, in very cold ambient temperatures, this condensate may tend to freeze before it exits the unit, thereby preventing further egress of collected condensate and buildup of ice that may affect operation of air conditioner unit 100 (e.g., such as by stalling outdoor fan 140 or crushing heat exchanger coils). Accordingly, condensate management system 200 may include one or more features that facilitate improved management of collected condensate.

[0051] According to an example embodiment, condensate management system 200 may be defined by or otherwise associated with base pan 120. In this regard, base pan 120 is generally positioned under outdoor heat exchanger 134. In addition, a condensate collection reservoir 202 may be defined by base pan 120 or may be positioned on base pan 120. In this manner, condensate that drips from outdoor heat exchanger 134 may be collected within condensate collection reservoir 202 and may be routed outside of air conditioner unit 100. Specifically, as shown for example in FIG. 9, base pan 120 may generally define one or more pan holes 204 that pass through base pan 120 along the vertical direction V from a top surface 206 to a bottom surface 208 of base pan 120. Specifically, as illustrated, pan holes 204 may be defined within condensate collection reservoir 202 to facilitate egress of condensate in a desired location through base pan 120.

[0052] As best illustrated in FIGS. 6 through 8, base pan 120 may generally be mounted within wall sleeve 104. Moreover, wall sleeve 104 and/or base pan 120 may define structural supports 210, support feet, or other suitable structure for securing base pan 120 within wall sleeve 104. Moreover, these features may define a gap 212 between bottom surface 208 of base pan 120 and a top surface 214 of a lower wall 216 of wall sleeve 104. In general, gap 212 may be suitably sized for facilitating the discharge of condensate through gap 212 and out one or more discharge apertures 218 defined on the exterior side portion 108 of wall sleeve 104. Accordingly, during operation of sealed system 102, condensate may fall off outdoor heat exchanger 134 where it is collects in condensate collection reservoir 202, passes through pan holes 204, and flows through gap 212 before being discharged through discharge apertures 218.

[0053] Notably, conventional air conditioner units include base pans that poorly regulate the flow of condensate, particularly in the routing of the condensate to the outside of the unit without permitting it to freeze and affect unit operation. Accordingly, aspects of the present subject matter are directed to a base pan assembly 230 with improved condensate management. In this regard, for example, base pan assembly 230 may include base pan 120 and an elevated wall 232 that extends upward from base pan 120 along the vertical direction V to collectively define condensate collection reservoir 202.

[0054] According to an example embodiment, elevated wall 232 may be formed within or attached to base pan 120 in any suitable manner. For example, elevated wall 232 may be integrally formed with base pan 120, e.g., using an injection molding process. According to alternative embodiments, elevated wall 232 may be a separate component that is attached to base pan 120 in any suitable manner, e.g., using mechanical fasteners, friction welding, adhesives, etc. According to still other embodiments, elevated wall 232 may be a defined extension of an outdoor fan shroud 234 or may be mounted directly to outdoor heat exchanger 134. Other constructions are possible and within the scope of the present subject matter.

[0055] Notably, the size and shape of elevated wall 232 addresses issues with condensate management issues that are common to conventional air conditioner units. For example, the size, geometry, and relative dimensions of elevated wall 232 and the condensation collection reservoir 202 that it defines reduce or eliminate the issues with freezing condensate in a novel and inventive manner. However, although a specific geometry is described herein, it should be appreciated that variations and modifications may be made to base pan assembly 230 while remaining within the scope of the present subject matter.

[0056] For example, according to an example embodiment of the present subject matter, condensate collection reservoir 202 defines a reservoir footprint (e.g., identified by reference numeral 236 in FIG. 9) in a horizontal plane (e.g., as defined by the lateral direction L and the transverse direction T). In addition, outdoor heat exchanger 134 defines a heat exchanger footprint (e.g., identified generally by reference numeral 238 in FIG. 9) in the horizontal plane. According to an example embodiment, reservoir footprint 236 is less than 10 times, less than 5 times, less than 3 times, less than 2 times, less than 1.5 times, or less than heat exchanger footprint 238. Notably, such a small relative footprint retains the condensate within an area immediately proximate to outdoor heat exchanger 134, which may be warm from the defrost cycle while condensate is draining, thereby minimizing the likelihood of the condensate freezing.

[0057] In addition, as illustrated, elevated wall 232 may fully enclose outdoor heat exchanger 134 within a horizontal plane. In this regard, elevated wall 232 may fully encircle outdoor heat exchanger 134 such that outdoor heat exchanger 134 fits entirely within condensate collection reservoir 202 in a horizontal plane. For example, elevated wall 232 may be continuous along a width of outdoor heat exchanger 134. According to an example embodiment, a portion of elevated wall 232 may be defined by a perimeter of base pan 120. Other constructions are possible and within the scope of the present subject matter.

[0058] In addition, to avoid the potential for condensate freezing and binding outdoor fan 140, elevated wall 232 may be positioned between outdoor heat exchanger 134 and outdoor fan 140. In this regard, elevated wall 232 may be positioned such that condensate collection reservoir 202 is spaced apart from the operating region of outdoor fan 140. Similarly, elevated wall 232 may be positioned such that condensate collection reservoir 202 is positioned entirely in front of or spaced apart from fan shroud 234.

[0059] According to an example embodiment, elevated wall 232 may also define a height (not labeled) that is greater than 2 millimeters, greater than 5 millimeters, greater than 10 millimeters, or greater. This may be advantageous for ensuring that the volume of condensate generated during a defrost cycle may be retained within condensate collection reservoir 202 and directed through a pan hole 204 positioned within elevated wall 232.

[0060] According to the embodiment illustrated in FIG. 9, condensate management system 200 may further include one or more valves that are operably coupled to pan holes 204 for selectively regulating the flow of water or condensate therethrough. In this regard, a thermostatic drain valve 240 may be operably coupled with each pan hole 204. When ambient temperatures are relatively high and the risk of condensate freezing is low, thermostatic drain valve 240 may remain closed. By contrast, when temperatures are relatively low and freezing is likely, thermostatic drain valve 240 may pop open to quickly and effectively discharge condensate from within condensate collection reservoir 202.

[0061] Notably, according to an example embodiment, base pan 120 may be formed from a plastic material, which may have a relatively low thermal conductivity. As a result, collected condensate may have a tendency to freeze, particularly at locations away from outdoor heat exchanger 134. In this regard, the condensate dripping from outdoor heat exchanger 134 may begin cooling as soon as it drips from the coils and may continue to cool as it travels through condensate collection reservoir 202 toward pan holes 204. Notably, conventional base pans include long and tortuous paths between the outdoor heat exchanger and drain holes, resulting in frequent freezing of condensate and operability issues, particularly in environments with low ambient temperatures.

[0062] Accordingly, aspects of the present subject matter may be directed to a condensate collection reservoir 202 that is localized around outdoor heat exchanger 134 and provides a short path to pan holes 204 for condensate egress from the unit. In this regard, for example, condensate collection reservoir 202 may be positioned directly below outdoor heat exchanger 134 and pan holes 204 may pass through base pan 204 within condensate collection reservoir 202. For example, pan holes 204 may be positioned such that the condensate flows unimpeded to pan holes 204 after falling from outdoor heat exchanger 134. In this regard, for example, elevated wall 232 may be designed to minimize redirection or diversion of the flow of condensate.

[0063] According to example embodiments, pan holes 204 may be positioned in front of fan shroud 234 along the transverse direction T, e.g., such that condensate drains through pan holes 204 before reaching the fan operating region. In addition, pan holes 204 may be positioned between lateral sides 242 (FIG. 9) of outdoor heat exchanger 134 along the lateral direction L. Pan holes 204 may also be defined between outdoor heat exchanger 134 and outdoor fan 140 along the transverse direction T.

[0064] Indeed, it may be desirable to minimize spacing between pan holes 204 and outdoor heat exchanger 134. Accordingly, pan holes 204 may be spaced apart from outdoor heat exchanger 134 by a hole spacing 244 (FIG. 9) defined along the transverse direction T. According to example embodiments, hole spacing 244 may be less than 50 millimeters, less than 25 millimeters, less than 10 millimeters, less than 5 millimeters, less than 1 millimeter, or less. In addition, it should be appreciated that the size of pan holes 204 may be selected to facilitate quick and efficient discharge of collected condensate. In addition, multiple pan holes 204 may be positioned at select locations to minimize the likelihood of freezing condensate, particularly near regions where operability issues may occur due to frozen condensate.

[0065] Notably, as condensate formed during a defrost cycle collects in condensate collection reservoir 202 and flows out of pan holes 204, it may continue to lower in temperature before exiting air conditioner unit 100. For example, as the flow of condensate (e.g., identified in FIG. 10 by reference numeral 250) flows out of pan holes 204 and into gap 212, the condensate 250 may be exposed to very low temperatures, particularly when the outside ambient temperature is very low, e.g., below freezing. In such conditions, the condensate 250 may freeze and clog gap 212, resulting in a backup of condensate into condensate collection reservoir 202 and many of the same operability issues described above. Accordingly, aspects of the present subject matter are directed to systems and methods of introducing additional thermal energy at desired times and desired locations to prevent such freezing.

[0066] For example, condensate management system 200 may further include a defrost heater 252 mounted within gap 212 defined between base pan 120 and wall sleeve 104. In this regard, defrost heater 252 may be any suitable heating element that is selectively energized, e.g., by controller 166, to add heat to condensate 250, particularly the condensate 250 flowing through gap 212 before exiting discharge apertures 218. For example, defrost heater 252 may be a thin resistive heater that is seated within or adjacent to gap 212 to provide heat under command from controller 166. Defrost heater 252 may be mounted in any suitable manner, such as using adhesive, mechanical fasteners, or any other suitable attachment means.

[0067] According to the illustrated embodiment of FIG. 10, defrost heater 252 may be mounted to wall sleeve 104, e.g., directly to top surface 214 of wall sleeve 104. In this manner, condensate 250 flowing through pan holes 204 may fall directly onto defrost heater 252 where heat may be added to prevent freezing before discharge from air conditioner unit 100. Thus, it may be desirable to mount defrost heater 252 in close proximity to pan holes 204, e.g., directly underneath pan holes 204 along the vertical direction V. In addition, according to example embodiments, defrost heater 252 may extend to discharge apertures 218 defined on wall sleeve 104.

[0068] As best illustrated in FIG. 10, defrost heater 252 may include additional features to facilitate the quick and efficient egress of condensate 250. For example, defrost heater 252 may define cutouts or channels 254 for guiding condensate 250 out of wall sleeve 104. These channels 254 may be grooves defined in the thin defrost heater 252 or other flow regulating pathways to efficiently collect and direct condensate 250 as it falls from pan holes 204 under the force of gravity. Indeed, it should be appreciated that the thickness, geometry, footprint, and configuration of defrost heater 252 may vary depending on the application while remaining within the scope of the present subject matter.

[0069] According to still other embodiments, defrost heater 252 may be mounted in any other suitable location where heat may be introduced into condensate 250. For example, according to alternative embodiments, defrost heater 252 may be mounted to bottom surface 208 of base pan 120. In addition, defrost heater 252 may be positioned such that it surrounds pan hole 204 to ensure the efficient transfer of thermal energy into the flow of condensate 250. In addition, such a positioning of defrost heater 252 may ensure that some residual heat flows into condensate collection reservoir 202, further reducing the likelihood of freezing, clogs, and operability issues.

[0070] Now that the construction of air conditioner unit 100 and defrost heater 252 have been described according to example embodiments of the present subject matter, an exemplary method 300 of operating an air conditioner unit will be described. Although the discussion below refers to the exemplary method 300 of operating defrost heater 252 of air conditioner unit 100, one skilled in the art will appreciate that the exemplary method 300 is applicable to the operation of a variety of other heating elements and air conditioner units.

[0071] In exemplary embodiments, the various method steps as disclosed herein may be performed by controller 166 or a separate, dedicated controller. In this regard, as described herein, controller 166 of air conditioner unit 100 may implement all steps of method 300. However, it should be appreciated that according to alternative embodiments, controller 166 may offload the performance of steps described herein, e.g., by communicating with a network or a remote server. Other distributed computing arrangements are possible and within the scope of the present subject matter.

[0072] Referring now to FIG. 11, method 300 includes, at step 310, determining that a defrost cycle is requested. For example, a defrost cycle may be requested by controller 166 or may be automatically initiated by a user or maintenance technician. Controller 166 may be programmed to perform a defrost cycle after performing a heat pump cycle, particularly in low ambient temperatures, when the formation of frost is likely. Alternatively, controller 166 may perform a defrost cycle based on a time schedule or sensed system conditions. As described above, the performance of the defrost cycle may include operating sealed system 102 to inject hot refrigerant through the coils of outdoor heat exchanger 134.

[0073] Step 320 may include obtaining an ambient temperature using the ambient temperature sensor. In this regard, continuing the example from above, controller 166 may utilize ambient temperature sensor 170 to measure the outdoor or ambient temperature where air conditioner unit 100 is operating. Step 330 may include determining that the ambient temperature falls below a predetermined temperature threshold. This predetermined temperature threshold may be set by the manufacturer, programmed by the user, or determined in any other suitable manner. For example, the predetermined temperature threshold may be a temperature at which condensate is likely to freeze, such as about 32 F. or lower.

[0074] If the defrost cycle is requested and the ambient temperature is below the threshold, step 340 may include activating the defrost heater and performing the defrost cycle. For example, controller 166 may be programmed to operate defrost heater 252 any time that the defrost cycle is being performed in low temperature ambient conditions. By operating defrost heater 252 in conjunction with the performance of the defrost cycle, frost and ice may melt to form condensate 250 that collects in condensate collection reservoir 202 and flows out of pan holes 204. Before the condensate 250 has a chance to freeze within gap 212, defrost heater 252 may introduce additional heat that raise the temperature sufficiently to permit the condensate 250 to flow through discharge apertures 218 and out of air conditioner unit 100 prior to freezing.

[0075] Notably, it may be desirable to save energy when ambient temperatures are elevated such that freezing of condensate 250 is not likely. Accordingly, method 300 may further include, at step 350, determining that the ambient temperature is at or above the predetermined temperature threshold. Upon such a determination, step 360 may include deactivating the defrost heater 252 to conserve energy while still performing the defrost cycle to clear the outdoor heat exchanger 134 of any frost. Similarly, if a defrost cycle has not been requested and is not being performed, method 300 may include stopping the operation of defrost heater 252, as the risk of condensate 250 being formed and freezing is minimal.

[0076] FIG. 11 depicts steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that the steps of any of the methods discussed herein can be adapted, rearranged, expanded, omitted, or modified in various ways without deviating from the scope of the present disclosure. Moreover, although aspects of method 300 are explained using air conditioner unit 100 and defrost heater 252 as an example, it should be appreciated that this method may be applied to the operation of air conditioner unit including a heating element.

[0077] As explained herein, aspects of the present subject matter are generally directed to a thin resistive heater between the base pan and the wall sleeve in an outdoor unit of a package terminal air conditioner. An underside heater may be fastened or bonded to plastic drain pan and may be energized when the defrost condition indicates that ice build-up is possible in the base pan. The resistive heater may connect to a port in the unit for control and power. Further, cut-outs may be formed on the heater to channel the condensate to an external drain.

[0078] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.