CONTROLLING A HEATER ASSEMBLY FOR AN AIR CONDITIONER UNIT UTILIZING TEMPERATURE SENSORS

FIELD

The present subject matter relates generally to air conditioner units, and more particularly to utilizing temperature sensors to control a heater control assembly in packaged terminal air conditioner units.

BACKGROUND

Air conditioner or conditioning units are conventionally utilized to adjust the temperature indoors, e.g., within structures such as dwellings and office buildings. Such units commonly include a closed refrigeration loop to heat or cool the indoor air. Typically, the indoor air is recirculated while being heated or cooled. A variety of sizes and configurations are available for such air conditioner units. For example, some units may have one portion installed within the indoors that is connected to another portion located outdoors, e.g., by tubing or conduit carrying refrigerant. These types of units are typically used for conditioning the air in larger spaces.

Another type of air conditioner unit, commonly referred to as single-package vertical units (SPVU) or package terminal air conditioners (PTAC), may be utilized to adjust the temperature in, for example, a single room or group of rooms of a structure. These units typically operate like split heat pump systems, except that the indoor and outdoor portions are defined by a bulkhead and all system components are housed within a single package that installed in a wall sleeve positioned within an opening of an exterior wall of a building.

When a conventional PTAC is operating in a cooling mode or a heating mode, a compressor circulates refrigerant within a sealed system, while indoor and outdoor fans urge flows of air across indoor and outdoor heat exchangers, respectively. In this manner, the indoor air may be cooled or heated, respectively. However, conventional PTACs may also include a heater assembly that is positioned within the indoor portion for providing supplemental heating to the flow of indoor air when the PTAC is operating in the heating mode.

In some instances, such as when the PTAC is operating in the heating mode, a lack of airflow to the heating assembly can cause the heating assembly to overheat. For example, a user may block or obstruct an intake air vent of the PTAC which may result in insufficient air flow to the heating assembly. To compensate for this, for example, to avoid overheating of the heating assembly, PTACs are often required to include a one shot thermal cutoff switch that cuts off power to the heating assembly when an ambient temperature threshold surrounding the heating assembly is met or exceeded. However, the one shot nature of the thermal cutoff switch may result in numerous drawbacks. For example, the one shot thermal cutoff switch may typically be placed in locations that are difficult to assess during factory assembly and field service and when tripped, the one shot thermal cutoff switch may require costly replacement.

Accordingly, an air conditioner unit that includes a heater control assembly for a PTAC that addresses one or more of the above-described drawbacks would be particularly beneficial.

BRIEF DESCRIPTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

In one exemplary embodiment, an air conditioner unit is provided. The air conditioner unit may define a vertical direction, a lateral direction, and a transverse direction. The air conditioner unit may include a cabinet. The air conditioner unit may also include a bulkhead positioned within the cabinet. The bulkhead may also define an indoor portion and an outdoor portion. The air conditioner unit may further include a refrigeration loop that may include an outdoor heat exchanger positioned within the outdoor portion and an indoor heat exchanger positioned within the indoor portion. The air conditioner unit may also include an indoor fan positioned within the indoor portion for selectively urging a flow of air through the indoor heat exchanger. The air conditioner unit may further include one or more heater banks for selectively heating the flow of air. The air conditioner unit may also include a heater control assembly mounted to the bulkhead. The heater control assembly may include a first temperature sensor positioned downstream of the indoor heat exchanger.

In another exemplary embodiment, a heater control assembly for an air conditioner unit is provided. The air conditioner unit may include a bulkhead that may define an indoor portion and an outdoor portion. An indoor fan may be positioned within the indoor portion for selectively urging a flow of air through an indoor heat exchanger. The air conditioner unit may also include one or more heater banks for selectively heating the flow of air. The heater control assembly may include a thermal cutoff switch that may be mounted adjacent the one or more heater banks. The thermal cutoff switch may cut off power to the one or more heater banks when a predetermined temperature is reached. The heater control assembly may further include a first temperature sensor positioned upstream of the thermal cutoff switch. The heater control assembly may also include a second temperature sensor positioned downstream of the thermal cutoff switch.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

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.

FIG. 1 provides a perspective view of an air conditioner unit, with part of an indoor portion exploded from a remainder of the air conditioner unit for illustrative purposes, in accordance with one or more exemplary embodiments of the present disclosure.

FIG. 2 is another perspective view of components of the indoor portion of the exemplary air conditioner unit of FIG. 1.

FIG. 3 is a schematic view of a refrigeration loop in accordance with one or more exemplary embodiments of the present disclosure.

FIG. 4 is a rear perspective view of an outdoor portion of the exemplary air conditioner unit of FIG. 1, illustrating a vent aperture in a bulkhead in accordance with one or more exemplary embodiments of the present disclosure.

FIG. 5 is a front perspective view of the exemplary bulkhead of FIG. 4 with a vent door illustrated in the open position in accordance with one or more exemplary embodiments of the present disclosure.

FIG. 6 is a rear perspective view of the exemplary air conditioner unit and bulkhead of FIG. 4 including a fan assembly for providing make-up air in accordance with one or more exemplary embodiments of the present disclosure.

FIG. 7 is a side cutaway view of the exemplary air conditioner unit of FIG. 1.

FIG. 8 is a side cross sectional view of the exemplary air conditioner unit of FIG. 1.

FIG. 9 is a front view of the exemplary air conditioner unit of FIG. 1 in accordance with one or more exemplary embodiments of the present disclosure.

FIG. 10 provides a flow chart illustrating an exemplary method of operating an air conditioner unit according to one or more exemplary embodiments of the present subject matter.

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

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.

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 terms “upstream” and “downstream” refer to the relative flow direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the flow direction from which the fluid flows, and “downstream” refers to the flow direction to which the fluid flows.

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 ten 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.

Referring now to FIGS. 1 and 2, an air conditioner unit 10 is provided. The air conditioner unit 10 may be a one-unit type air conditioner, also conventionally referred to as a room air conditioner or a packaged terminal air conditioner (PTAC). The unit 10 may include an indoor portion 12 and an outdoor portion 14, and may generally define a vertical direction V, a lateral direction L, and a transverse direction T each of which being mutually perpendicular to each other, such that an orthogonal coordinate system is generally defined. Although aspects of the present subject matter are described with reference to PTAC unit 10, 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.

A housing 20 of the unit 10 may contain various other components of the unit 10. Housing 20 may include, for example, a rear grill 22 and a room front 24 which may be spaced apart along the transverse direction T by a wall sleeve 26. The rear grill 22 may be part of the outdoor portion 14, and the room front 24 may be part of the indoor portion 12. Components of the outdoor portion 14, such as an outdoor heat exchanger 30, an outdoor fan 32, and a compressor 34 may be housed within the wall sleeve 26. A fan shroud 36 may additionally enclose outdoor fan 32, as shown.

Indoor portion 12 may include, for example, an indoor heat exchanger 40, a blower fan or indoor fan 42, and a heating unit 44. These components may, for example, be housed behind the room front 24. Additionally, a bulkhead 46 may generally support and/or house various other components or portions thereof of the indoor portion 12, such as indoor fan 42 and the heating unit 44. Bulkhead 46 may generally separate and define the indoor portion 12 and outdoor portion 14.

Outdoor and indoor heat exchangers 30, 40 may be components of a sealed system or refrigeration loop 48, which is shown schematically in FIG. 3. Refrigeration loop 48 may, for example, further include compressor 34 and an expansion device 50. As illustrated, compressor 34 and expansion device 50 may be in fluid communication with outdoor heat exchanger 30 and indoor heat exchanger 40 to flow refrigerant therethrough as is generally understood. More particularly, refrigeration loop 48 may include various lines for flowing refrigerant between the various components of refrigeration loop 48, thus providing the fluid communication there between. Refrigerant may thus flow through such lines from indoor heat exchanger 40 to compressor 34, from compressor 34 to outdoor heat exchanger 30, from outdoor heat exchanger 30 to expansion device 50, and from expansion device 50 to indoor heat exchanger 40. The refrigerant may generally undergo phase changes associated with a refrigeration cycle as it flows to and through these various components, as is generally understood. Suitable refrigerants for use in refrigeration loop 48 may include pentafluoroethane, difluoromethane, or a mixture such as R410a, although it should be understood that the present disclosure is not limited to such examples and rather that any suitable refrigerant may be utilized.

As is understood in the art, refrigeration loop 48 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 refrigeration loop 48 is operating in a cooling mode and thus performing a refrigeration cycle, the indoor heat exchanger 40 acts as an evaporator and the outdoor heat exchanger 30 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 40 acts as a condenser and the outdoor heat exchanger 30 acts as an evaporator. The outdoor and indoor heat exchangers 30, 40 may each include coils through which a refrigerant may flow for heat exchange purposes, as is generally understood.

According to an example embodiment, compressor 34 may be a variable speed compressor. In this regard, compressor 34 may be operated at various speeds depending on the current air conditioning needs of the room and the demand from refrigeration loop 48. For example, according to an exemplary embodiment, compressor 34 may be configured to operate at any speed between a minimum speed, e.g., 1500 revolutions per minute (RPM), to a maximum rated speed, e.g., 3500 RPM. Notably, use of variable speed compressor 34 enables efficient operation of refrigeration loop 48 (and thus air conditioner unit 10), minimizes unnecessary noise when compressor 34 does not need to operate at full speed, and ensures a comfortable environment within the room.

Specifically, according to an exemplary embodiment, compressor 34 may be an inverter compressor. In this regard, compressor 34 may include a power inverter, power electronic devices, rectifiers, or other control electronics suitable for converting an alternating current (AC) power input into a direct current (DC) power supply for the compressor. The inverter electronics may regulate the DC power output to any suitable DC voltage that corresponds to a specific operating speed of compressor. In this manner compressor 34 may be regulated to any suitable operating speed, e.g., from 0% to 100% of the full rated power and/or speed of the compressor. This may facilitate precise compressor operation at the desired operating power and speed, thus meeting system needs while maximizing efficiency and minimizing unnecessary system cycling, energy usage, and noise.

In exemplary embodiments as illustrated, expansion device 50 may be disposed in the outdoor portion 14 between the indoor heat exchanger 40 and the outdoor heat exchanger 30. According to the exemplary embodiment, expansion device 50 may be an electronic expansion valve (“EEV”) that enables controlled expansion of refrigerant, as is known in the art. According to alternative embodiments, expansion device 50 may be a capillary tube or another suitable expansion device configured for use in a thermodynamic cycle.

More specifically, according to exemplary embodiments, electronic expansion device 50 may be configured to precisely control the expansion of refrigerant to maintain, for example, a desired temperature differential of the refrigerant across the evaporator (i.e., the outdoor heat exchanger 30 in heat pump mode). In other words, electronic expansion device 50 throttles the flow of refrigerant based on the reaction of the temperature differential across the evaporator or the amount of superheat temperature differential, thereby ensuring that the refrigerant is in the gaseous state entering compressor 34.

In general, the terms “superheat,” “operating superheat,” or the like are generally intended to refer to the temperature increase of the refrigerant past the fully saturated vapor temperature in the evaporator. In this regard, for example, the superheat may be quantified in degrees Fahrenheit, e.g., such that 1° F. superheat means that the refrigerant exiting the evaporator is 1° F. higher than the saturated vapor temperature. It should be appreciated that the operating superheat may be measured and monitored by controller 64 in any suitable manner. For example, controller 64 may be operably coupled to a pressure sensor for measuring the refrigerant pressure exiting the evaporator, may convert that pressure to the saturated vapor temperature, and may subtract that temperature from the measured refrigerant temperature at the evaporator outlet to determine superheat.

According to exemplary embodiments, expansion device or electronic expansion valve 50 may be driven by a stepper motor or other drive mechanism to any desirable position between a fully closed position (e.g., when no refrigerant passes through EEV 50) to a fully open position (e.g., when there is little or no restriction through the EEV 50). For example, controller 64 may be operably coupled to EEV 50 and may regulate the position of the EEV 50 through a control signal to achieve a target superheat, a target restriction/expansion, etc.

More specifically, the control signal communicated from controller 64 may specify the number of control steps (or simply “steps”) and a corresponding direction (e.g., counterclockwise toward the closed position or clockwise toward the open position). Each EEV 50 may have a physical stroke span equal to the difference between the fully open position and the fully closed position. In addition, the EEV 50 may include a step range or range of control steps that correspond to the number adjustment steps it take for the EEV 50 to travel from the fully closed position to the fully open position.

Each “step” may refer to a predetermined rotation of the drive mechanism, e.g., such as a stepper motor, which may in turn move the EEV 50 a fixed linear distance toward the open or closed position (depending on the commanded step direction). For example, according to the exemplary embodiment, the EEV 50 may have a step range of 500 steps, with 0 steps corresponding to fully closed and 500 steps corresponding to fully open. However, it should be appreciated that according to alternative embodiments, any given electronic expansion valve may include a different number of control steps, and the absolute step adjustments described herein may be varied accordingly.

In addition, as used herein, the position of EEV 50 may be expressed as a percentage, e.g., where 0% corresponds to a fully closed position and 100% corresponds to a fully open position. According to exemplary embodiments, this percentage representation may also refer to the percentage of total control steps taken from the closed position, e.g., with 10% referring to 50 steps (e.g., 10% of the 500 total steps), 80% referring to 400 steps (e.g., 80% of 500 total steps), etc.

According to the illustrated exemplary embodiment, outdoor fan 32 is an axial fan and indoor fan 42 is a centrifugal fan. However, it should be appreciated that according to alternative embodiments, outdoor fan 32 and indoor fan 42 may be any suitable fan type. In addition, according to an exemplary embodiment, outdoor fan 32 and indoor fan 42 are variable speed fans, e.g., similar to variable speed compressor 34. For example, outdoor fan 32 and indoor fan 42 may rotate at different rotational speeds, thereby generating different air flow rates. It may be desirable to operate fans 32, 42 at less than their maximum rated speed to ensure safe and proper operation of refrigeration loop 48 at less than its maximum rated speed, e.g., to reduce noise when full speed operation is not needed. In addition, according to alternative embodiments, fans 32, 42 may be operated to urge make-up air into the room.

According to the illustrated embodiment, indoor fan 42 may operate as an evaporator fan in refrigeration loop 48 to encourage the flow of air through indoor heat exchanger 40. Accordingly, indoor fan 42 may be positioned downstream of indoor heat exchanger 40 along the flow direction of indoor air and downstream of heating unit 44. Alternatively, indoor fan 42 may be positioned upstream of indoor heat exchanger 40 along the flow direction of indoor air and may operate to push air through indoor heat exchanger 40.

Heating unit 44 in exemplary embodiments includes one or more heater banks 60. Each heater bank 60 may be operated as desired to produce heat. In some embodiments, for example, as illustrated in FIG. 2, three heater banks 60 may be utilized. Alternatively, however, any suitable number of heater banks 60 may be utilized. For instance, as illustrated in FIG. 9, one heater bank 60 may be utilized. Each heater bank 60 may further include at least one heater coil or coil pass 62, such as in exemplary embodiments two heater coils or coil passes 62. Alternatively, other suitable heating elements may be utilized.

The operation of air conditioner unit 10 including compressor 34 (and thus refrigeration loop 48 generally) indoor fan 42, outdoor fan 32, heating unit 44, expansion device 50, and other components of refrigeration loop 48 may be controlled by a processing device such as a controller 64. Controller 64 may be in communication (via for example a suitable wired or wireless connection) to such components of the air conditioner unit 10. Controller 64 may include a memory and one or more processing devices such as 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 unit 10. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor.

Unit 10 may additionally include a control panel 66 and one or more user inputs 68, which may be included in control panel 66. The user inputs 68 may be in communication with the controller 64. A user of the unit 10 may interact with the user inputs 68 to operate the unit 10, and user commands may be transmitted between the user inputs 68 and controller 64 to facilitate operation of the unit 10 based on such user commands. A display 70 may additionally be provided in the control panel 66 and may be in communication with the controller 64. Display 70 may, for example, be a touchscreen or other text-readable display screen, or alternatively 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 the unit 10.

Referring briefly to FIG. 4, a vent aperture 80 may be defined in bulkhead 46 for providing fluid communication between indoor portion 12 and outdoor portion 14. Vent aperture 80 may be utilized in an installed air conditioner unit 10 to allow outdoor air to flow into the room through the indoor portion 12. In this regard, in some cases it may be desirable to allow outside air (i.e., “make-up air”) to flow into the room in order, e.g., to meet government regulations, to compensate for negative pressure created within the room, etc. In this manner, according to an exemplary embodiment, make-up air may be provided into the room through vent aperture 80 when desired.

As shown in FIG. 5, a vent door 82 may be pivotally mounted to the bulkhead 46 proximate to vent aperture 80 to open and close vent aperture 80. More specifically, as illustrated, vent door 82 is pivotally mounted to the indoor facing surface of indoor portion 12. Vent door 82 may be configured to pivot between a first, closed position where vent door 82 prevents air from flowing between outdoor portion 14 and indoor portion 12, and a second, open position where vent door 82 is in an open position (as shown in FIG. 5) and allows make-up air to flow into the room. According to the illustrated embodiment vent door 82 may be pivoted between the open and closed position by an electric motor 84 controlled by controller 64, or by any other suitable method.

In some cases, it may be desirable to treat or condition make-up air flowing through vent aperture 80 prior to blowing it into the room. For example, outdoor air which has a relatively high humidity level may require treating before passing into the room. In addition, if the outdoor air is cool, it may be desirable to heat the air before blowing it into the room. Therefore, according to an exemplary embodiment of the present subject matter, unit 10 may further include an auxiliary sealed system that is positioned over vent aperture 80 for conditioning make-up air. The auxiliary sealed system may be a miniature sealed system that acts similar to refrigeration loop 48, but conditions only the air flowing through vent aperture 80. According to alternative embodiments, such as that described herein, make-up air may be urged through vent aperture 80 without the assistance of an auxiliary sealed system. Instead, make-up air urged through vent aperture 80 may be conditioned at least in part by refrigeration loop 48, e.g., by passing through indoor heat exchanger 40. Additionally, the make-up air may be conditioned immediately upon entrance through vent aperture 80 or sequentially after combining with the air stream induced through indoor heat exchanger 40.

Referring now to FIG. 6, a fan assembly 100 will be described according to an exemplary embodiment of the present subject matter. According to the illustrated embodiment, fan assembly 100 is generally configured for urging the flow of makeup air through vent aperture 80 and into a conditioned room without the assistance of an auxiliary sealed system. However, it should be appreciated that fan assembly 100 could be used in conjunction with a make-up air module including an auxiliary sealed system for conditioning the flow of make-up air. As illustrated, fan assembly 100 includes an auxiliary fan 102 for urging a flow of make-up air through a fan duct 104 and into indoor portion 12 through vent aperture 80.

According to the illustrated embodiment, auxiliary fan 102 is an axial fan positioned at an inlet of fan duct 104, e.g., upstream from vent aperture 80. However, it should be appreciated that any other suitable number, type, and configuration of fan or blower could be used to urge a flow of makeup air according to alternative embodiments. In addition, auxiliary fan 102 may be positioned in any other suitable location within air conditioner unit 10 and auxiliary fan 102 may be positioned at any other suitable location within or in fluid communication with fan duct 104. The embodiments described herein are only exemplary and are not intended to limit the scope of the present subject matter.

Referring now to FIG. 7, operation of unit 10 will be described according to an exemplary embodiment. More specifically, the operation of components within indoor portion 12 will be described during a cooling operation or cooling cycle of unit 10. To simplify discussion, the operation of auxiliary fan 102 for providing make-up air through vent aperture 80 will be omitted, e.g., as if vent door 82 were closed. Although a cooling cycle will be described, it should be further appreciated that indoor heat exchanger 40 and/or heating unit 44 may be used to heat indoor air according to alternative embodiments. Moreover, although operation of unit 10 is described below for the exemplary packaged terminal air conditioner unit, it should be further appreciated that aspects of the present subject matter may be used in any other suitable air conditioner unit, such as a heat pump or split unit system.

As illustrated, room front 24 of unit 10 generally defines an intake vent 110 and a discharge vent 112 for use in circulating a flow of air (indicated by arrows 114) throughout a room. In this regard, indoor fan 42 is generally configured for drawing in air 114 through intake vent 110 and urging the flow of air through indoor heat exchanger 40 before discharging the air 114 out of discharge vent 112. According to the illustrated embodiment, intake vent 110 is positioned proximate a bottom of unit 10 and discharge vent 112 is positioned proximate a top of unit 10. However, it should be appreciated that according to alternative embodiments, intake vent 110 and discharge vent 112 may have any other suitable size, shape, position, or configuration.

During a cooling cycle, refrigeration loop 48 is generally configured for urging cold refrigerant through indoor heat exchanger 40 in order to lower the temperature of the flow of air 114 before discharging it back into the room. Specifically, during a cooling operation, controller 64 may be provided with a target temperature, e.g., as set by a user for the desired room temperature. In general, components of refrigeration loop 48, outdoor fan 32, indoor fan 42, and other components of unit 10 operate to continuously cool the flow of air.

In order to facilitate operation of refrigeration loop 48 and other components of unit 10, unit 10 may include a variety of sensors for detecting conditions internal and external to the unit 10. These conditions can be fed to controller 64 which may make decisions regarding operation of unit 10 to rectify undesirable conditions or to otherwise condition the flow of air 114 into the room. For example, as best illustrated in FIG. 7, unit 10 may include an indoor temperature sensor 120 which is positioned and configured for measuring the indoor temperature within the room. In addition, unit 10 may include an indoor humidity sensor 122 which is positioned and configured for measuring the indoor humidity within the room. In this manner, unit 10 may be used to regulate the flow of air 114 into the room until the measured indoor temperature reaches the desired target temperature and/or humidity level. According to exemplary embodiments, unit 10 may further include an outdoor temperature sensor for measuring ambient outdoor temperatures.

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 120 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 120 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 unit 10 may include any other suitable number, type, and position of temperature, and/or other sensors according to alternative embodiments.

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 122 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 122 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 10 may include any other suitable number, type, and position of humidity sensors according to alternative embodiments.

Referring now to FIGS. 8 and 9, the exemplary air conditioner unit 10 according to one or more exemplary embodiments of the present subject matter may be provided. Specifically, FIG. 8 illustrates a side cross sectional view of the exemplary air conditioner unit 10 and FIG. 9 illustrates a front view of the exemplary air conditioner unit 10. In some embodiments, for instance, as illustrated in FIGS. 8 and 9, the air conditioner unit 10 may include a heater control assembly 200 that may be mounted to the bulkhead 46.

In general, the heater control assembly 200 may be provided to detect a blockage condition of the air conditioner unit 10. For instance, a blockage condition of the air conditioner unit 10 may occur when the flow of air 114 may be blocked, obstructed, or restricted. For example, a blockage condition of the air conditioner unit 10 may occur when the intake vent 110, the discharge vent 112, or a combination thereof, are partially, or entirely, blocked, e.g., the flow of air 114 may be inhibited from entering or exiting the intake vent 110 or the discharge vent 112 due to the blockage. In addition, the heater control assembly 200 may be utilized to maintain a safe operating temperature of the heating unit 44. In some embodiments, the heating unit 44 may include one or more heater banks 60, for instance, a single heater bank 60 as illustrated in FIGS. 8 and 9, which each may be operated as desired to produce heat. In some embodiments, see, for example, FIG. 8, the one or more heater banks 60 may generally extend from a front 210 to a back 212 approximately along the transverse direction T.

In some embodiments, the heater control assembly 200 may include a thermal cutoff switch 202, a first temperature sensor 204, and a second temperature sensor 206 that each may be mounted to a bracket 208 extended from the bulkhead 46. As illustrated in FIG. 9, the bulkhead 46 may extend between a first side 45, for example, the left side when viewed from the front as in FIG. 9, and a second side 47, for example, the right side when viewed from the front as in FIG. 9, approximately along the lateral direction L. In general, terms such as “left” and “right may be used with reference to the perspective of a user accessing the air conditioner unit 10. In some embodiments, the bracket 208 may be extended from the second side 47 of the bulkhead 46 to provide an accessible location, for example, for installation and maintenance, of the heater control assembly 200.

In some embodiments, the thermal cutoff switch 202 may be mounted adjacent to the one or more heater banks 60. In addition, the thermal cutoff switch 202 may be electrically coupled to the one or more heater banks 60, for instance, the thermal cutoff switch 202 may be connected in series with the one or more heater banks 60 such that the thermal cutoff switch 202 may cut off power to the one or more heater banks 60 when a predetermined temperature threshold, for example, a maximum allowable temperature of the ambient air surrounding the heating unit 44, may be met. For example, the thermal cutoff switch 202 may be provided to cut off power to the one or more heater banks 60 to protect the one or more heater banks 60 from overheating, for example, when the one or more heater banks 60 may operate without the flow of air 114 passing over them, for instance, during a blockage condition of the air conditioner unit 10.

In this regard, the thermal cutoff switch 202 may be provided to avoid or prevent unsafe operating conditions of the air conditioner unit 10 by breaking an electrical connection to the one or more heater banks 60 when the predetermined temperature threshold is met or exceeded. For example, in some embodiments the thermal cutoff switch 202 may contain a low melting point alloy that may melt and break the electrical current to the one or more heater banks 60 when the predetermined temperature threshold is met or exceeded. As another example, in some embodiments, the thermal cutoff switch 202 may include a bimetallic strip that may bend and break the electrical connection to the one or more heater banks 60 when the predetermined threshold is met or exceeded.

In some embodiments, the thermal cutoff switch 202 may be a one shot thermal cutoff switch 202 that may permanently break the electrical connection to the one or more heater banks 60 when the thermal cutoff switch 202 is tripped. Particularly, when the one shot thermal cutoff switch 202 is tripped it may not be reenergized or reused until the air conditioner unit 10 is repaired, for example, until the blockage of air flow 114 is cleared, and the thermal cutoff switch 202 is replaced.

Replacement of the thermal cutoff switch 202 may be costly and time consuming. Accordingly, embodiments of the present disclosure provide the first temperature sensor 204 and the second temperature sensor 206 of the heater control assembly 200. For instance, as illustrated in FIGS. 8 and 9, the first temperature sensor 204 and the second temperature sensor 206 may be positioned such that the ambient temperature surrounding the heating unit 44 and specifically surrounding the thermal cutoff switch 202 is monitored. In general, the ambient temperature upstream and downstream of the thermal cutoff switch 202 may be monitored by the first temperature sensor 204 and the second temperature sensor 206, respectively. In this regard, any change in the ambient temperature within the heating unit 44, and more specifically surrounding the thermal cutoff switch 202, may be detected and corrected prior to the thermal cutoff switch 202 being tripped.

Particularly, in some embodiments, the first temperature sensor 204 may be positioned downstream of the indoor heat exchanger 40 and upstream of the thermal cutoff switch 202. In addition, the first temperature sensor 204 may be positioned proximate the front 210 of the one or more heater banks 60, wherein “positioned proximate the front” may refer to the first temperature sensor 204 being positioned closer to the front 210 of the one or more heater banks 60 than the back 212 of the one or more heater banks 60 approximately along or approximately parallel to the transverse direction T. Further, the first temperature sensor 204 may be positioned above the one or more heater banks 60 approximately along or approximately parallel to the vertical direction V.

In some embodiments, for instance, as illustrated in FIG. 8, the second temperature sensor 206 may be positioned downstream of the indoor heat exchanger 40 and downstream of the thermal cutoff switch 202. In addition, the second temperature sensor 206 may be positioned proximate the back 212 of the one or more heater banks 60, for instance, as illustrated in phantom in FIG. 9. As used herein the phrase “positioned proximate the back 212” may refer to the second temperature sensor 206 being positioned closer to the back 212 of the one or more heater banks 60 than the front 210 of the one or more heater banks 60 approximately along or approximately parallel to the transverse direction T. Further, the second temperature sensor 206 may be positioned above the one or more heat banks 60 approximately along or parallel to the vertical direction V.

In some embodiments, the controller 64 may be operably coupled to the one or more heater banks 60, the first temperature sensor 204, and the second temperature sensor 206. Prior to operation of the air conditioner unit 10, the controller 64 may be provided with the predetermined temperature threshold. In some embodiments, the predetermined temperature threshold may be a temperature set by regulations, for example, government regulations, and may correspond to the temperature at which the thermal cutoff switch 202 may be tripped.

During operation of the air conditioner unit 10, a first temperature reading of the flow of air 114 upstream, and more specifically, immediately upstream, of the thermal cutoff switch 202 may be obtained by the first temperature sensor 204 and a second temperature reading of the flow of air 114 downstream, and more specifically, immediately downstream, of the thermal cutoff switch 202 may be obtained by the second temperature sensor 206.

The first temperature reading, the second temperature reading, or a combination thereof, may be fed to the controller 64, wherein the controller 64 may be configured to adjust or throttle an amperage and/or wattage power output to the one or more heater banks 60 by adjusting the voltage to regulate an electrical current to the one or more heater banks 60. In this regard, the ambient temperature of the heating unit 44, and more particularly, the ambient temperature surrounding the thermal cutoff switch 202 may be maintained below the predetermined temperature threshold.

Moreover, if it is detected that there is sudden change in the conditions of the air conditioner unit 10 that may potentially damage the heating unit 44 or cause an unsafe heating condition, for instance, if it is detected that there is a blocking condition, the controller 64 may throttle the amperage and/or wattage power output to the one or more heater banks 60 or the controller 64 may execute a rapid shutdown of the one or more heater banks 60.

Referring now to FIG. 10, embodiments of the present subject matter may include one or more methods for operating an air conditioner unit, such as the exemplary air conditioner unit 10 described above, as well as other possible exemplary air conditioner units. The exemplary methods according to the present subject matter may include a method 300, for example, as illustrated in FIG. 10. A controller of the air conditioner unit 10, such as the controller 64, may be programmed to implement method 300, for example, the controller, such as controller 64, may be capable of and may be operable to perform any methods and associated method steps as disclosed herein.

In some embodiments the method 300 may include a step 310 of obtaining a first temperature reading of a flow of air upstream of a thermal cutoff switch. As described above, an indoor fan, for example, indoor fan 42, may generally be configured to draw in a flow of air, for instance, the flow of air 114, through an intake vent of the air conditioner unit during a heating cycle of the air conditioner unit. In some embodiments, at step 310 the first temperature reading of the flow of air passing through the heating unit, for example, heating unit 44, may be obtained with a first temperature sensor, for example, first temperature sensor 204 of the exemplary air conditioner unit 10, that may be positioned upstream of a thermal cutoff switch, for example, the thermal cutoff switch 202 of the exemplary air conditioner unit 10.

During the heating cycle of the air conditioner unit, one or more heater banks, for example, one or more heater banks 60, may be configured to generate heat. Thus, during the heating cycle of the air conditioner unit, the one or more heater banks may heat the flow of air passing through the heating unit. As described above, the air conditioner unit may include a thermal cutoff switch that is provided to cut off power to the one or more heater banks when a predetermined temperature threshold, for instance, an unsafe operating temperature, is met or exceeded. Thus, in some embodiments, the method 300 may include a step 320 of adjusting, based on the obtained first temperature reading, for instance, as obtained at the step 310, an output of the one or more heater banks. In some embodiments, in response to the output of the one or more heater banks being adjusted, the thermal cutoff switch may not be tripped, for example, the thermal cutoff switch may not break the electrical connection to the one or more heater banks.

The step 320 may include a step of comparing the first temperature reading to a temperature threshold, wherein adjusting the output of one or more heater banks may include adjusting the output of the one or more heater banks based on the comparison of the first temperature reading to the first temperature threshold. In some embodiments, the first temperature threshold may be less than a cutoff temperature of the thermal cutoff switch, whereby adjusting the output of the one or more heater banks based on the comparison of the first temperature reading to the first temperature threshold prevents the thermal cutoff switch from being tripped.

For instance, in some embodiments, the first temperature threshold may be less than the cutoff temperature of the thermal cutoff switch, for instance, the maximum allowable temperature of the thermal cutoff switch, to provide a temperature buffer for the heating unit of the air conditioner unit. In this regard, the first temperature reading may be compared to the temperature threshold to determine if the first temperature reading, for instance, the temperature of the flow of air immediately upstream of the thermal cutoff switch, is close to, or nearing, the temperature threshold.

In response to this determination, the output of the one or more heater banks may be adjusted. For instance, if it is determined that the first temperature reading is too close to the temperature threshold, the output of the one or more heater banks may be throttled, for instance, lowered, or suspended in order to maintain a safe operating temperature of the heating unit.

Additionally, in some embodiments, the air conditioner unit may include a second temperature sensor, for example, second temperature sensor 206, positioned downstream of the thermal cutoff switch. In such embodiments, the method 300 may include a step of obtaining a second temperature reading of the flow of air downstream of the thermal cutoff switch. In some embodiments, the second temperature reading of the air passing through the heating unit, for example, the heating unit 44, may be obtained with a second temperature sensor, for example, the second temperature sensor 206 of the exemplary air conditioner unit 10, that may be positioned downstream of the thermal cutoff switch, for example, the thermal cutoff switch 202 of the exemplary air conditioner unit 10.

In some embodiments, at step 320, the output of the one or more heater banks may additionally, or alternatively, be adjusted based on the obtained second temperature reading. For instance, in some embodiments, at the step 320, the output of the one or more heater banks may be adjusted based on the obtained first temperature reading, the obtained second temperature reading, or a combination thereof. In some embodiments, the second temperature sensor may be a backup temperature sensor that may be used in combination with the first temperature sensor to ensure accurate temperature readings of the temperature proximate the thermal cutoff switch.

Embodiments of the present subject matter advantageously utilize strategically positioned temperature sensors, for instance, upstream and downstream of the one or more heater banks and aligned toward a forward plane of the heater banks, to monitor the temperature around a thermal cutoff switch. The present subject matter may advantageously prevent or mitigate tripping of the thermal cutoff switch during a blockage condition by detecting the temperature changes in the vicinity of the thermal cutoff switch and adjusting the heater banks output based on the detected temperature change. In addition, the placement of the first temperature sensor and the second temperature sensor may advantageously offer a more secure and efficient way of monitoring and controlling the temperature of the heating unit, which may advantageously prevent accidental tripping of the thermal cutoff switch and ensures safe heating, thereby enhancing the durability and reliability of the heater. Furthermore, embodiments of the present subject matter may advantageously improve installation and repair of the air conditioner unit. For instance, the location of the thermal cutoff switch and mounting components allows for smaller, more compact, mounting components, and more accessible installation locations.

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.

CONTROLLING A HEATER ASSEMBLY FOR AN AIR CONDITIONER UNIT UTILIZING TEMPERATURE SENSORS

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