Detecting blockage of air conditioner unit based on fan speed

Air conditioner units and methods for operating air conditioner units are provided. A method includes determining a steady state speed of a blower fan of the air conditioner unit. The method further includes receiving a call for heating and activating the blower fan in response to the call for heating. The method further includes measuring a speed of the blower fan after activating the blower fan and comparing the measured speed of the blower fan to the steady state speed of the blower fan. When the measured speed of the blower fan is greater than the steady state speed of the blower fan, the method includes disabling one of a plurality of heater banks of a heating unit of the air conditioner unit.

FIELD OF THE INVENTION

The present disclosure relates generally to air conditioner units, and more particularly to methods and apparatus for detecting blockage of air conditioner units.

BACKGROUND OF THE INVENTION

Air conditioner units are conventionally utilized to adjust the temperature within structures such as dwellings and office buildings. In particular, one-unit type room air conditioner units may be utilized to adjust the temperature in, for example, a single room or group of rooms of a structure. A typical such air conditioner unit includes an indoor portion and an outdoor portion. The indoor portion is generally located indoors, and the outdoor portion is generally located outdoors. Accordingly, the air conditioner unit generally extends through a wall, window, etc. of the structure.

In the outdoor portion of a conventional air conditioner unit, a compressor that operates a refrigerating cycle is provided. At the back of the outdoor portion, an outdoor heat exchanger connected to the compressor is disposed, and facing the outdoor heat exchanger, an outdoor fan for cooling the outdoor heat exchanger is provided. At the front of the indoor portion of a conventional air conditioner unit, an air inlet is provided, and above the air inlet, an air outlet is provided. A blower fan and a heating unit are additionally provided in the indoor portion. Between the blower fan and heating unit and the air inlet, an indoor heat exchanger connected to the compressor is provided.

When cooling operation starts, the compressor is driven to operate the refrigerating cycle, with the indoor heat exchanger serving as a cold-side evaporator of the refrigerating cycle, and the outdoor heat exchanger as a hot-side condenser. The outdoor heat exchanger is cooled by the outdoor fan to dissipate heat. As the blower fan is driven, the air inside the room flows through the air inlet into the air passage, and the air has its temperature lowered by heat exchange with the indoor heat exchanger, and is then blown into the room through the air outlet. In this way, the room is cooled.

When heating operation starts, the heating unit is operated to raise the temperature of air in the air passage. The air, having had its temperature raised, is blown out through the air outlet into the room to heat the room.

In many currently known air conditioner units, the heating unit is formed from a plurality of heater banks. Each bank may have a different rated power output. The highest output for the unit generally occurs when all heater banks are operating at the same time. Additionally, many currently known air conditioner units have multiple blower fan speed settings. For example, a blower fan may in some cases be operated at a low setting or a high setting, or in some cases at various other intermediate settings.

One concern during operation of air conditioner units is overheating of the unit, particularly if a blockage occurs. For example, a blockage to the air inlet path and/or air outlet path prevents proper airflow from occurring within the unit. Particularly when all heater banks are on and the airflow is low due to blockage, temperatures within the unit can rise significantly, leading to deformation and/or other damage to components of the unit. Particularly vulnerable components include, for example, plastic components of the heater housing.

Accordingly, improved methods and apparatus for operating air conditioner units are desired. In particular, methods and apparatus that detect blockage of the air conditioner unit would be advantageous.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with one embodiment, a method for operating an air conditioner unit is provided. The method includes determining a steady state speed of a blower fan of the air conditioner unit. The method further includes receiving a call for heating and activating the blower fan in response to the call for heating. The method also includes measuring a speed of the blower fan after activating the blower fan in response to the call for heating and comparing the measured speed of the blower fan to the steady state speed of the blower fan. When the measured speed of the blower fan is greater than the steady state speed of the blower fan, the method includes disabling one of a plurality of heater banks of a heating unit of the air conditioner unit.

In accordance with another embodiment, an air conditioner unit is provided. The air conditioner unit includes a blower fan, the blower fan comprising a blade assembly and a motor connected to the blade assembly. The air conditioner unit further includes a heating unit, the heating unit comprising a plurality of heater banks. The air conditioner unit further includes a power source in electrical communication with the blower fan motor and the plurality of heater banks, and a controller in operable communication with the motor and the plurality of heater banks. The controller is operable for determining a steady state speed of the blower fan, receiving a call for heating, activating the blower fan after receiving the call for heating, measuring a speed of the blower fan after activating the blower fan, comparing the measured speed of the blower fan to the steady state speed of the blower fan, and disabling one of the plurality of heater banks when the measured speed of the blower fan is greater than the steady state speed of the blower fan.

DETAILED DESCRIPTION OF THE INVENTION

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 “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. As used herein, terms of approximation such as “generally,” “about,” or “approximately” include values within ten percent greater or less than the stated value. 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 toFIG. 1, an air conditioner unit10is provided. The air conditioner unit10is a one-unit type air conditioner, also conventionally referred to as a room air conditioner. The unit10includes an indoor portion12and an outdoor portion14, and generally defines a vertical direction V, a lateral direction L, and a transverse direction T. The directions V, L, and T are mutually perpendicular to each other, such that an orthogonal coordinate system is generally defined.

A housing20of the unit10may contain various other components of the unit10. Housing20may include, for example, a rear grill22and a room front24which may be spaced apart along the transverse direction T by a wall sleeve26. The rear grill22may be part of the outdoor portion14, while the room front24is part of the indoor portion12. Components of the outdoor portion14, such as an outdoor heat exchanger30, outdoor fan (not shown), and compressor (not shown) may be housed within the wall sleeve26. A casing34may additionally enclose the outdoor fan, as shown.

Referring now also toFIGS. 2 and 3, indoor portion12may include, for example, an indoor heat exchanger40, a blower fan42, and a heating unit44. These components may, for example, be housed behind the room front24. In at least some embodiments, the unit10may also include a reversing valve for reversing a direction of refrigerant flow between the outdoor heat exchanger30and the indoor heat exchanger40to provide a heat pump operation mode, as is generally understood in the art. Additionally, a heater housing46may generally support and/or house various other components or portions of the indoor portion12, such as the blower fan42and the heating unit44.

Heater housing46may have peripheral surfaces50that define a housing interior51. For example, the peripheral surfaces50may include a first sidewall52and a second sidewall54which are spaced apart along the lateral direction L. Peripheral surfaces50may additionally include a base pan56and an outlet air diverter58, each of which may extend between the sidewalls52,54along the lateral direction L.

The housing46may be formed from one or more components. For example, in exemplary embodiments, the housing46may be formed from a bulkhead60and a shroud62. The bulkhead60may in some embodiments be formed from a suitable plastic, or alternatively may be formed from any suitable material. The shroud62may in some embodiments be formed from a suitable metal, or alternatively may be formed from any suitable material. The shroud62may be connected to the bulkhead60, and the bulkhead60and shroud62may together include the peripheral surfaces50. For example, base pan56and outlet air diverter58may be components of the bulkhead60, and portions of or entire sidewalls52,54may be components of the shroud62. Shroud62may additionally include an interior shroud base64, which may for example be disposed within interior51adjacent base pan56.

In exemplary embodiments, blower fan42may be a tangential fan. Alternatively, however, any suitable fan type may be utilized. Blower fan42may include a blade assembly70and a motor72. The blade assembly70, which may include one or more blades disposed within a fan housing74, may be disposed within the interior51of the heater housing46. As shown, blade assembly70may for example extend along the lateral direction L between the first sidewall52and the second sidewall54. The motor72may be connected to the blade assembly70, such as through the housing74to the blades via a shaft. Operation of the motor72may rotate the blades, thus generally operating the blower fan42. Further, in exemplary embodiments, motor72may be disposed exterior to the heater housing46. Accordingly, the shaft may for example extend through one of the sidewalls52,54to connect the motor72and blade assembly70.

Heating unit44in exemplary embodiments includes one or more heater banks80. Each heater bank80may be individually powered, separately from other heater banks80, to provide heat. In exemplary embodiments, three heater banks80may be utilized. Further, each heater bank80may in some embodiments have a different rated power level. For example in some embodiments, a heating unit44may include a low power heater bank, a medium power heater bank, and a high power heater bank. In some exemplary embodiments, heating unit44include a 1000 Watt bank80, a 1400 Watt bank80, and a 2400 Watt bank80. Each heater bank80may further include at least one heater coil or coil pass82, such as in exemplary embodiments two heater coils or coil passes82. As shown, in exemplary embodiments multiple heater banks80may be stacked vertically, and the coils82of a heater bank80may be arranged side-by-side. Accordingly, in exemplary embodiments wherein each heater bank80has two heater coils82the coils82may be arranged in two columns and three rows as shown.

The operation of air conditioner unit10, including blower fan42, heater banks80, heating coils82thereof, and other suitable components, may be controlled by a processing device such as a controller85. Controller85may be in operable communication with, e.g., operably connected to (via for example a suitable wired or wireless connection) such components of the air conditioner unit10. By way of example, the controller85may 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 unit10. 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.

Unit10may additionally include a control panel87and one or more user inputs89, which may be included in control panel87. The user inputs89may be in communication with the controller85. A user of the unit10may interact with the user inputs89to operate the unit10, and user commands may be transmitted between the user inputs89and controller85to facilitate operation of the unit10based on such user commands. A display88may additionally be provided in the control panel87, and may be in communication with the controller85. Display88may, 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, such as when one or more of the heater banks80is disabled, as described below.

A power source90may supply power to the unit10generally, and specifically to the controller85, fan42(and motor72thereof) and heater banks80. Power source90may generally be any suitable electrical power source, such as a power cable that is connected to the various components of the unit10. Power source90may interact with a power supply92, such as the electrical grid, via for example a power outlet and suitable wiring as is generally understood. The power source90may thus generally provide the electrical communication between the power supply92and the unit10generally and components thereof.

Unit10may additionally include a temperature sensor95, which may be disposed within the interior51of housing46to measure, for example, temperatures during a heating mode when the heating unit44generally is active and/or temperature during a cooling mode. Sensor95may be in communication with the controller85, and may provide such temperature readings to the controller85.

As discussed, improved methods and apparatus for detecting blockage of air conditioner units10during operation thereof would be advantageous. Accordingly, the present disclosure is further directed to methods for operating air conditioner units10. It should further be understood that, in exemplary embodiments, a controller85in accordance with the present disclosure may be operable to perform the various methods steps as disclosed herein. Controller85may advantageously be in communication with, for example, the motor72and the heater banks80to facilitate such operation.

Turning now toFIG. 4, a method300may thus include, for example, the step310of determining a steady state speed (RPMSS) of the blower fan42of the air conditioner unit10. In at least some embodiments, the steady state speed (RPMSS) may be determined based on an estimated voltage of the power supply92, e.g., according to method200as shown inFIG. 5and described below. In various embodiments, the RPMSSmay be stored in a memory, e.g., the controller85may include a memory, as described above, and such memory may be used to store the RPMSSvalue. In some embodiments, suitable components such as speed sensors, rotational frequency sensors, etc. may be utilized to determine, e.g., measure, the steady state speed (RPMSS) of the blower fan42.

The method300may also include a step320of receiving a call for heating, e.g., from the controller85. For example, the call for heating may be in response to a signal from one or more temperature sensors during an automatic mode of operation of the unit10, and/or may be in response to a user input received via the user inputs89. When the call heating is received by the air conditioner unit10at step320, the method300may include step330of activating the blower fan42. For example, the blower fan42may be activated at step330by providing a control signal to the blower fan42, e.g., to the motor72thereof. Such control signal may, for example, be a pulse width modulation (PWM) signal. As is generally understood by those of skill in the art, the PWM signal may include a duty cycle which corresponds to the speed of the blower fan42. For example, the PWM signal provided in step330may have a duty cycle of between about fifteen percent (15%) and about thirty percent (30%), such as about twenty-three and a half percent (23.50%).

Method300may also include a step340of measuring a speed (RPMACT) of the blower fan42after activating the blower fan42at step330. In at least some embodiments, step340may include measuring RPMACTfollowing a delay, e.g., of at least about five seconds, after activating the blower fan42to allow the fan42to come up to speed. The control signal, e.g., PWM signal, provided in step330may be continued at least through the measuring step340and may be the same as a control signal provided when determining the steady state speed (RPMSS) of the blower fan42. For example, both the steady state speed (RPMSS) and the actual speed (RPMACT) of the blower fan42may be measured and/or determined while providing a PWM signal having a duty cycle of, e.g., 23.5%, as described above. The step340of measuring the actual speed (RPMACT) of the blower fan42may include determining an average speed of the blower fan over time, e.g., taking a ten-second average speed of the blower fan42. For example, the average may be taken over a ten-second window beginning five seconds after initial activation of the blower fan42, e.g., the measuring step340may be performed from about five seconds of operation of the blower fan42to about fifteen seconds of operation of the blower fan42.

Method300may further include, for example, the step350of comparing the measured speed (RPMACT) of the blower fan42to the steady state speed (RPMSS) of the blower fan42. For example, the step350may include determining whether the measured speed (RPMACT) is greater than the steady state speed (RPMSS), such as whether the measured speed (RPMACT) is greater than the steady state speed (RPMSS) by an at least an offset or threshold amount, which is denoted by “X” inFIG. 4. For example, the threshold amount X may be about twenty rotations per minute (RPM) or more, such as about twenty-five RPM or more, such as about thirty RPM or more. When RPMACTis greater than the steady state speed RPMSS, e.g., by at least the threshold amount X, a blockage may be detected.

For example, when airflow through the air conditioner unit10is impeded or blocked, the blower fan42may essentially spin freely while moving little or no air, e.g., less air than would be moved by the blower fan42when the airflow through the air conditioner unit10is unimpeded. Accordingly, when the airflow is blocked, the blower fan does42does less work, e.g., moves less air than in the unimpeded airflow state, and the power supplied to the blower fan42translates into higher rotational speeds. Thus, where the same power is supplied to the blower fan42and the speed of rotation increases, a blockage may be detected. For example, when the same PWM signal is provided for measuring the steady state speed (RPMSS) and for measuring the actual speed (RPMACT), and RPMACTis greater than RPMSS, such as greater by at least the threshold amount X, a blockage may be detected.

When a blockage is detected, e.g., when the determination at step350is positive, the method300may include, for example, a step360of disabling one of the plurality of heater banks80and, optionally, a step365of providing heat pump heating (e.g., by actuating a reversing valve as described above) as a supplement to the resistance heating. Thus, the step360may include activating one of the heater banks80and disabling another of the heater banks80. Method300may further include a step370of continuing a cycle at a reduced heating level. In some embodiments, such step360may only occur when the measured speed of the blower fan is greater than the steady state speed of the blower fan, such as only when RPMACTis greater than RPMSSby at least the threshold amount X. In some embodiments, more than one of the heater banks80may be disabled. For example, in embodiments having more than one heater bank80, all but one heater bank80may be disabled. As mentioned above, in some embodiments, three heater banks80may be provided, each with a different power, such as a low power heater bank, a medium power heater bank, and a high power heater bank. In such embodiments, when the call for heating at step320corresponds to or indicates a medium heating setting or a high heating setting, and when a blockage is detected at step350, the medium power heater bank and the high power heater bank may be disabled at step360and the reduced heating level at step370may be a low power level, such as about 1000 Watts. Step360may include various combinations of disabling the medium power heater bank and/or the high power heater bank while activating only the low power heater bank and/or medium power heater bank. Additionally or alternatively, method300may include providing heat pump heating at step365. For example, all of the heater banks80may be disabled and only heat pump heating may be provided when a blockage is detected, or the heat pump heating may be provided in combination with a reduced-power resistance heating level. A reduced-power heating level includes activating fewer of the plurality of heater banks80than are called for based on the call for heating at step320. For example, where the call for heating at step320corresponds to or indicates a high heating mode and the high power heater bank is disabled at step360, the resistance heating provided by the low power heater bank and/or medium power heater bank at steps360and370in response to the call for a high heating mode at step320would be an example of a reduced-power resistance heating level. Method300may also include additional steps when a blockage is detected, such as decreasing the speed of the blower fan42, such as by decreasing the duty cycle of the PWM control signal, when RPMACTis greater than RPMSS.

When the determination at step350is negative, the method300may include a step380of activating the resistance heating, e.g., activating the heating unit44of the air conditioner unit10. As mentioned above, the heating unit44may include a plurality of heater banks80of varying power levels which may correspond to various heating modes or settings. Thus, step380may include activating the resistance heating per the call for heating from step320, e.g., providing power to each of the one or more heater banks80which corresponds to the call for heating received at step320. For example, activating the high power heater bank, e.g., 2400 Watt bank, at step380when the call for heating at step320corresponds to or indicates a high heating mode. The method300may further include, at step390, continuing normal operation of the air conditioner unit10, with no further action taken with respect to presently disclosed methods. The continuation of normal operation in accordance with the present disclosure is generally continuance of operation of the unit10in accordance with the present settings, with no adjustments in accordance with the present method.

In some embodiments, method300may additionally provide an indication that a heater bank80has been disabled. For example, method300may further include transmitting a heater bank inactive signal when RPMACTis greater than RPMSS. Such signal may, for example, be transmitted by the controller85to, for example, the display88. Such transmission, and resulting output provided by the display88, may advantageously provide an indication to a user that a heater bank80has been disabled.

Referring now toFIG. 5, an exemplary method200of determining the steady state speed of the fan42based on a voltage VSSof the power supply92is illustrated. Knowing the voltage VSSmay be useful to the air conditioner unit10for various reasons, in addition to determining the speed of the blower fan42. Thus, in some embodiments, determining RPMSS, such as in the method200and in step310of the method300described above, may include storing VSSin the memory of the controller85and calculating RPMSSbased on the stored value of VSS. In such embodiments, step350of the method300described above may then include comparing the calculated speed RPMSSwith the measured speed RPMACTto determine if a blockage may be present. Such embodiments may advantageously reduce the memory requirements, by calculating RPMSSbased on VSSrather than storing both VSSand RPMSSin the memory where VSSis stored in the memory anyway for additional purposes.

Thus, as shown inFIG. 5, a method of determining RPMSSmay include a step210of activating the blower fan42and a step220of running the blower fan42until the fan speed reaches a steady state condition, e.g., after a delay of about five seconds to about ten seconds. As mentioned above, a control signal may be provided to the blower fan42during and throughout the activating step210and the running step220, e.g., a PWM signal having a duty cycle within the ranges set forth above. Also as mentioned above, the steady state speed may be an average speed over time, e.g., over about ten seconds. Once the steady state condition has been reached, the method200may include a step230of measuring the steady state blower fan speed RPMSS. Based on RPMSSmeasured at step230, the voltage VSSsupplied to the blower fan42may be estimated. For example, fan speed at a given PWM duty cycle may have a generally linear relationship with the input voltage VSSsuch that VSScan be estimated based on the measured RPMSSby applying a linear function which relates rotational speed of the blower fan42to the voltage supplied. Thus, a value of VSSmay be output at step250from the step240, and such output may, for example, be stored in the memory of the controller85. The method200may further include a step260of activating the air conditioner unit10, e.g., when an operation cycle of the air conditioner unit10is started. After activating the air conditioner unit10, the method200may include a step270of estimating RPMSSbased on VSS. For example, the controller85may calculate RPMSSbased on a value of VSSstored in the memory of the controller85, such as the value of VSSfrom step250, e.g., by applying the linear relationship described above. The method may then output a value of RPMSSat280, for example, the calculated value of RPMSSmay be used in steps310and350of the method300, as described above.

Method200may be performed, for example, in a factory setting, and the resulting value(s) for VSSand/or RPMSSmay be stored in the memory of the controller85before the air conditioner unit10is installed. Method200may also or instead be performed during initial setup of the air conditioner unit10after installation, and/or during maintenance of the air conditioner unit10after installation. Thus, the steady state speed at step240may be measured under controlled conditions, e.g., in the factory or during maintenance, and the steady state speed at steps270and280may be calculated or estimated on demand during operation of the air conditioner unit10, e.g., based on VSSstored in memory. For example, during operation of the air conditioner unit10may be any time after the air conditioner unit10is activated at step260, e.g., in a field setting or end-use setting such as after installed in a room of a dwelling or office building (or hotel room, etc.).