Patent Publication Number: US-2020292193-A1

Title: System and method for faulting to return air sensor

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Application Ser. No. 62/817,827, entitled “SYSTEM AND METHOD FOR FAULTING TO RETURN AIR SENSOR” and filed on Mar. 13, 2019, which is expressly incorporated by reference herein in its entirety. 
    
    
     FIELD 
     The present disclosure generally relates to control of heating, ventilation, and air conditioning (HVAC) systems, and more specifically to systems and methods for faulting to a return air temperature sensor. 
     BACKGROUND 
     Generally, HVAC systems rely on network connectivity and wireless or wired sensors to operate without a formal thermostat. Thus, an HVAC system can power up and power down based on readings from the sensors and user defined setpoint information for a temperature and/or a humidity level. Users can program setpoint information on their mobile devices via a user interface in many advanced HVAC systems. However, in some cases, the remote sensor may fail or the HVAC system may be unable to communicate with the sensor. 
     In this situation, the HVAC system must still continue to heat or cool the building (e.g., a house), but cannot operate without base information regarding the current conditions inside a particular building. In prior configurations, a thermostat provided conditioning information and allowed users to identify a setpoint. Furthermore, conventional thermostats were typically wired, so lost connections were rather uncommon. However, with the elimination of a thermostat, when network connectivity is lost, or communication with the remote sensors are lost, the HVAC system cannot function properly. 
     Therefore, there is a need for systems and methods that allow uninterrupted heating or cooling even in the event that one or more sensors within a building are unavailable. 
     SUMMARY 
     The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later. 
     The present disclosure provides temperature control systems, apparatuses, and methods. 
     In an aspect, a system for faulting to a return air sensor integrated within a heating, ventilation, and air conditioning (HVAC) unit includes a memory configured to store a set of instructions; and a processor coupled with the memory and configured to execute the instructions. The processor is configured to transmit a signal to a remote sensor. The processor is further configured to determine that a return signal is not received from the remote sensor. The processor is further configured to obtain a temperature reading from the return air sensor. The processor is further configured to determine whether the temperature reading satisfies a temperature setting stored in the memory. The processor is further configured to, in response to determining that the temperature reading does not satisfy the temperature setting, enable heating or cooling of the HVAC unit until the temperature setting is satisfied. The processor is further configured to, in response to determining that the temperature reading satisfies temperature setting, disable heating or cooling of the HVAC unit. 
     In another aspect, a method for faulting to a return air sensor integrated within a heating, ventilation, and air conditioning (HVAC) unit is provided. The method includes transmitting a signal to a remote sensor. The method further includes determining that a return signal is not received from the remote sensor. The method further includes obtaining a temperature reading from the return air sensor. The method further includes determining whether the temperature reading satisfies a temperature setting. The method further includes, in response to determining that the temperature reading does not satisfy the temperature setting, enabling heating or cooling of the HVAC unit until the temperature setting is satisfied. The method further includes, in response to determining that the temperature reading satisfies the temperature setting, disabling heating or cooling of the HVAC unit. 
     In a further aspect, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium stores instructions that, when executed by a processor, cause the processor to fault to a return air sensor integrated within a heating, ventilation, and air conditioning (HVAC) unit. The processor is configured to transmit a signal to a remote sensor. The processor is further configured to determine that a return signal is not received from the remote sensor. The processor is further configured to obtain a temperature reading from the return air sensor. The processor is further configured to determine whether the temperature reading satisfies a temperature setting. The processor is further configured to, in response to determining that the temperature reading does not satisfy the temperature setting, enabling heating or cooling of the HVAC unit until the temperature setting is satisfied. The processor is further configured to, in response to determining that the temperature reading satisfies the temperature setting, disabling heating or cooling of the HVAC unit. 
     To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an example of an HVAC system according to aspects of the present disclosure. 
         FIG. 2  is a flow diagram for an example method of defaulting to a return air temperature sensor, according to aspects of the present disclosure. 
         FIG. 3  is a block diagram of an example controller according to aspects of the present disclosure. 
         FIG. 4  is a block diagram of an example mobile device according to aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Various aspects of the disclosure are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to promote a thorough understanding of one or more aspects of the disclosure. It may be evident in some or all instances, however, that any aspects described below can be practiced without adopting the specific design details described below. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate description of one or more aspects. The following presents a simplified summary of one or more aspects of the disclosure in order to provide a basic understanding thereof. 
     Referring to  FIG. 1 , an HVAC system  100  for a building  10  is disclosed. The HVAC system  100  may include an HVAC unit  110  configured to control an ambient condition of the one or more rooms of the building  10  based on information from one or more sensors  150  and a remote user device  160 . In an example, an ambient condition may be a temperature or a humidity level. As shown by  FIG. 1 , the HVAC unit  110  may be external to the building  10 . In an aspect, one or more components (e.g., air conditioning (A/C) unit  112 , furnace  114 , blower  116 , communications component  130 , or controller  140 ) may be located in different locations including inside the building  10 . The building may be a home, office or any other structure that includes uses an HVAC system for controlling one or more ambient conditions of the structure. 
     In an aspect, the HVAC system  100  may include supply ducts  120  and return ducts  124  installed within the building  10  and coupled with the HVAC unit  110 . The supply ducts  120  may supply air to the building  10 , and the return ducts  124  may return air from the building  10 . The supply ducts  120  may receive supply air through one or more of intakes  128  that provide outside air to the HVAC system  100  and/or may recycle return air from the return ducts  124 . The supply ducts  120  may output the supply air at one or more of the rooms of the building  10  via one or more supply vents  122 . The return ducts  124  may receive return air from the building  10  via the return ducts  124  to balance air within the building  10 . The return air may be input into the return ducts  124  via one or more return vents  126 . In one aspect, one or more return air sensor(s)  125  may be located within the return air duct  124 , external to the building  10 , though in some configurations, the one or more return air sensor(s)  125  may be located in the building  10  within the return air duct  124  also. In  FIG. 1 , the return air sensor  125  is integrated within the HVAC unit  110 , e.g., is located inside the return ducts  124  within the HVAC unit  110 , but alternative locations are also contemplated herein. The return air sensor  125  measures the temperature or other settings such as humidity or the like of the air returning from the building  10  through the return duct  124 . 
     The HVAC unit  110  may include one or more of an A/C unit  112 , a furnace  114 , a blower  116 , a humidifier/dehumidifier  118 , or any other component (e.g., heat pump, not shown) for adjusting an ambient condition of a room of the building  10 . The A/C unit  112  may be configured to cool the supply air by passing the supply air through or around one or more cooled pipes (e.g., chiller pipes) to lower a temperature of the supply air. The furnace  114  may be configured to warm the supply air by passing the supply air through or around one or more warmed pipes (e.g., heating coils) to raise a temperature of the supply air. The blower  116  may be configured to blow the supply air through the supply ducts  120  to the building  10  and pull the return air from the building  10 . 
     The HVAC unit  110  may also include a communications component  130  configured to communicate with the one or more sensors  150  and/or the remote user device  160 . In an aspect, the communications component  130  may communicate with the one or more sensors  150  and/or the remote user device  160  via one or more communications links  132 . In an example, the communications component  130  may include one or more antennas, processors, modems, radio frequency components, and/or circuitry for communicating with the sensor  150  and/or the remote user device  160 . The one or more communications links  132  may be wired or wireless communication links. 
     The HVAC system  100  may also include the one or more sensors  150  located within one or more rooms of the building  10  and/or within or near the supply vents  122 . One or more sensors  150  may be configured to detect an ambient condition such as a temperature or a humidity level of the room where the sensor  150  is located, or even occupancy of the room (using, e.g., optical beam interruption for recognizing movement or the like). Each of the sensors  150  may provide sensor information  131  to the HVAC unit  110 . Examples of a sensor  150  may include a temperature sensor, a humidity sensor, or any sensor configured to detect an ambient condition of one or more rooms of the building  10 . 
     The HVAC system  100  may also include the remote user device  160  configured to communicate with the HVAC unit  110 . The remote user device  180  may include an HVAC application  162  configured to display, adjust, and store setpoint information (“info”)  164  indicating desired user settings for one or more rooms of the building  10 . In an example, the setpoint information  164  may include temperature settings  166  indicating one or more desired temperatures (e.g., minimum and/or maximum room temperatures) for one or more rooms of the building and/or humidity settings  188  indicating a desired humidity level for one or more rooms of the building  10 . The remote user device  160  may provide the setpoint information  164  to the HVAC unit  110 . Examples of a remote user device  160  may include a mobile device, a cellular phone, a smart phone, a personal digital assistant (PDA), a smart speaker, a home assistant, a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a smart watch, an entertainment device, an Internet of Things (IoT) device, or any device capable of communicating with the HVAC unit  110 . A smart speaker may include, for example, an Echo® device available from Amazon, Inc. of Seattle, Wash., a Google Home® device available from Google, Inc. of Mountain View, Calif., or other similar devices. The HVAC application  162  may include a voice interface that response to voice commands. 
     The HVAC unit  110  may also include a controller  140  configured to control the A/C unit  112 , the furnace  114 , and the blower  116  based on the sensor information  131  received from the one or more sensors  150  and the setpoint information  164  received from the remote user device  160 . The controller may communicate with the communications component  130 , the A/C unit  112 , the furnace  114 , and/or the blower  116  via a communications bus  134 . The controller  140  may include logic to determine when to initiate the blower  116  along with one of the A/C unit  112  or the furnace  114  based on the sensor information  131  and the setpoint information  164 . The controller  140  may also include logic to determine a time and/or a speed to run the blower  116  along with a time or power level to run one of the A/C unit  112  or the furnace  114  based on the sensor information  131  and the setpoint information  164 . 
     The controller  140  may further comprise an operation control component  142  to perform the logic of the controller  140 , the operation control component  142  comprising a monitoring component  144 , a system initiator  146  and a sensor default component  152 . The controller  140 , in some instances, may be unable to communicate with the one or more remote sensor(s)  150 . In this case, in order to continue uninterrupted operation of the HVAC unit  110 , the controller  140  may rely on the sensor default component  152 , a component of the operation control component  142  to default to reading temperatures from the return air sensor  125  for temperature and/or humidity readings. The sensor default component  152  determines whether a return signal is received from the one or more remote sensors  150 , using for example, the monitoring component  144  that receives readings via the sensor information (“info”) receiver  148 . 
     In some aspects, the controller  140  waits a predetermined period of time (e.g., approximately thirty seconds to one minute) with no communication prior to using the return air sensor  125  for temperature readings. In some aspects, the sensor default component  152  may flag the absence of a return signal from the one or more remote sensors  150  and issue a warning to a user of the HVAC unit  110  that communication is lost with the one or more remote sensors  150 . The warning may be issued on a user interface  304  (shown in  FIG. 3 ) associated with the HVAC unit, and/or sent as an alert to the user&#39;s mobile device(s)  160 , using the communications component  130 . Additionally, the warning may be displayed on the external warning indicator  302  (shown in  FIG. 3 ) of the HVAC unit  110 . In some aspects of the present disclosure, the warning or alert may be an email, text message or any other type of notification, for example a notification associated with an HVAC application  162  on the mobile device(s)  160 . 
     In some aspects, the sensor default component  152  may use a comparer  149  to compare a reading obtained from the return air sensor  125  with the setpoint information  164 . If the reading from the return air sensor  125  does not satisfy the temperature settings  166 , the system initiator  146  will start or stop one or more components of the HVAC unit  110 , e.g., the furnace  114 , the A/C  112 , the blower  116 , etc., until the conditions specified in the temperature settings  166  are satisfied. If the reading from the return air sensor  125  is equal to or within the minimum and maximum temperature specified in the settings  166 , the sensor default component  152  does not initiate the blower  116 . 
     In one non-limiting aspect, for example, when the HVAC unit  110  is configured/set for providing heating functionality (e.g., during winter), if the reading from the return air sensor  125  is less than a corresponding minimum temperature setting specified in the temperature settings  166 , the system initiator  146  may start the furnace  114  and the blower  116  to circulate heated air into the building  10  to reduce the reading returned from the return air sensor  125  to meet the temperature settings  166 . For example, in an aspect, the system initiator  146  may operate the furnace  114  and the blower  116  until the reading from the return air sensor  125  is greater than or equal to a corresponding maximum temperature setting specified in the temperature settings  166 . 
     In another non-limiting aspect, for example, when the HVAC unit  110  is configured/set for providing cooling functionality (e.g., during summer), if the reading from the return air sensor  125  is greater than a corresponding maximum temperature specified in the temperature settings  166 , the system initiator  146  may start the A/C  112  and the blower  116  to circulate cooled air into the building  10  to reduce the reading returned from the return air sensor  125  to meet the temperature settings  166 . For example, in an aspect, the system initiator  146  may operate the A/C  112  and the blower  116  until the reading from the return air sensor  125  is less than or equal to a corresponding minimum temperature setting specified in the temperature settings  166 . 
       FIG. 3  shows further detail regarding the controller  140 , including a user interface  304  along with a warning indicator  306  that is enabled when the monitoring component  144  determines that communication with the remote sensor(s)  150  is unavailable. Further,  FIG. 3  illustrates that the controller  140  may include a processor  320  and memory  322 , the memory  322  storing, for example, last setpoint information  330  in case network communication is lost along with stage setting(s)  340  that control various stages of operation of the HVAC unit  110  if it is a multi-stage unit. Further detail regarding the implementation of controller  140  is shown in  FIG. 5 . 
       FIG. 2  is a flow diagram for a method  200  for defaulting to a return air sensor by the HVAC unit  110 , where the return air sensor is integrated within the HVAC unit  110 , in accordance with some aspects of the present disclosure. The method  200  may implement the functionality described herein with reference to  FIG. 1  and may be performed by one or more components of the HVAC unit  110  as described herein with reference  FIGS. 1 and 3 . 
     The method  200  begins at  202 , where the method  200  may include determining whether a network connection is available to the network the HVAC unit  110  may connect to. If the connection is available, the method  200  proceeds to  204 . However, if it is detected that the connection is unavailable, the method  200  proceeds to  208 , described below, where the return air sensor is used to control the HVAC unit. For example, one or more components (e.g., controller  140 , processor  320 , operation controller  142  or monitoring component  144 ) of the HVAC unit  110  may determine whether the network connection is available or unavailable. 
     At  204 , the method  200  may also include transmitting a signal to one or more of the remote sensors  150 . For example, one or more components (e.g., controller  140 , processor  320 , operation controller  142  or monitoring component  144 ) of the HVAC unit  110  may transmit the signal to one or more remote sensors  150 . 
     At  206 , the method  200  may also include determining that a return signal is not received from the one or more remote sensors  150 . For example, one or more components (e.g., controller  140 , processor  320 , operation controller  142  or monitoring component  144 ) of the HVAC unit  110  may determine that the return signal is not received. In some aspects, the component waits a predetermined period of time (e.g., thirty seconds to one minute, though this is configurable or preset) prior to continuing with method  200 . In some aspects, the component may flag the absence of a return signal from the one or more remote sensors  150  and issue a warning to a user of the HVAC unit  110  that communication is lost with the one or more remote sensors  150 . The warning may be issued on a user interface  304  associated with the HVAC unit, and/or sent as a notification to the user&#39;s mobile device(s)  160 . Additionally, the warning may be displayed on the external warning indicator  302  of the HVAC unit  110 . In some aspects of the present disclosure, the warning may be an email, text message or any other type of notification, for example a notification associated with an HVAC application  162  on the mobile device(s)  160 . 
     At  208 , the method  200  may also include obtaining a temperature reading from a return air temperature sensor (e.g., return air sensor  125  integrated within the HVAC unit  110  as shown in  FIG. 1 ) as a value representative of the temperature inside the house. For example, one or more components (e.g., controller  140 , processor  320 , operation controller  142  or monitoring component  144 ) of the HVAC unit  110  may obtain the temperature reading from the return air sensor  125 . In some aspects, a significant amount of time may have passed since the blower  116  of the HVAC unit  110  has been off. Therefore readings from the return air sensor  125  may not be fully representative of the air temperature inside the building  10 . Further, the return air sensor  125  may be located external to the building  10  and may be influenced by external temperatures. Therefore, in this aspect, prior to obtaining a reading from the return air sensor  125 , the component may determine that the HVAC unit  110  is in an off cycle (e.g., the blower  116  is off) for a predetermined period of time and enable one or more fans of the blower  116  of the HVAC unit  110  to circulate air from the respect unit into the building  10  by powering up the blower  116 . In some aspects, the air may be recirculated for a predetermined period of time. Then, when several cycles of air have flowed in and returned to the HVAC unit  110  via the return air duct  124  (i.e., circulated) or a predetermined amount of time has passed (e.g., five minutes), readings from the return air sensor  125  may be significantly more representative of temperatures inside the building  10 . Thus, after the air circulates for several cycles, the component may then obtain a temperature reading from the return air sensor  125  before continuing with the method  200 . 
     At  210 , the method  200  may also include determining whether the obtained readings satisfy a temperature setting specified in the last setpoint information  330  stored in the memory  322  of the controller  140 . For example, one or more components (e.g., controller  140 , processor  320 , operation controller  142  or monitoring component  144 ) of the HVAC unit  110  may compare the obtained temperature with a last setpoint information  330  stored in the controller  140 . In some aspects, the temperature outside of the house may be significantly different than the temperature inside of the house and may affect the return air sensor  125  that is generally also located outside the building  10  within the return air duct  124  near the HVAC unit  110 . In this instance, it may be advantageous to, prior to comparing the obtained temperature, obtain ambient temperature information if it is available. For example, ambient temperature information may be obtained by ambient air temperature sensors (not shown) located outside the HVAC unit  110  or elsewhere outside the building  10 . In other aspects, external temperature information may be obtained through the Internet through a weather service or the like. Once the external temperature is received, the reading obtained from the return air sensor  125  may be offset by the external temperature reading. 
     If at  210 , the reading from the return air sensor  125  is equal to or within the minimum and maximum temperatures specified in the temperature settings  166 , the sensor default component  152  does not initiate the blower  116  and the method  200  returns to  202 . However, in response to determining that the obtained reading does not satisfy the conditions specified in the temperature settings  166 , the method  200  proceeds to  212 . 
     At  212 , the method  200  may also include enabling heating or cooling of the HVAC unit  110 . For example, one or more components (e.g., controller  140 , processor  320 , operation controller  142  or monitoring component  144 ) of the HVAC unit  110  may enable the heating or cooling of the HVAC unit  110 , as described above with reference to  FIG. 1 . For example, in one non-limiting aspect, when the HVAC unit  110  is configured/set for providing heating functionality (e.g., during winter), if the reading from the return air sensor  125  is less than a corresponding minimum temperature setting specified in the temperature settings  166 , the system initiator  146  may start the furnace  114  and the blower  116  to circulate heated air into the building  10  until the reading returned from the return air sensor  125  meets the temperature settings  166 . For example, in an aspect, the system initiator  146  may operate the furnace  114  and the blower  116  until the reading from the return air sensor  125  is greater than or equal to a corresponding maximum temperature setting specified in the temperature settings  166 . In another non-limiting aspect, for example, when the HVAC unit  110  is configured/set for providing cooling functionality (e.g., during summer), if the reading from the return air sensor  125  is greater than a corresponding maximum temperature setting specified in the temperature settings  166 , the system initiator  146  may start the A/C  112  and the blower  116  to circulate cooled air into the building  10  until the reading returned from the return air sensor  125  meets the temperature settings  166 . For example, in an aspect, the system initiator  146  may operate the A/C  112  and the blower  116  until the reading from the return air sensor  125  is less than or equal to a corresponding minimum temperature setting specified in the temperature settings  166 . 
     Once the reading from the return sensor  125  comes within a particular threshold value of the temperature settings  166 , the method  200  may return to  202 , operating periodically until return signals are received. 
     Though not shown in  FIG. 3 , after the setpoint in the setpoint information  164  is reached, the controller  140  may continuously detect whether communications with the one or more remote sensors  150  have resumed. If communications have resumed, the HVAC unit  110  operates according to readings from the one or more remote sensors  150  instead of the return air sensor  125 . Alternatively, if all of the one or more remote sensors  150  are still unavailable, the method  200  restarts at  202 . In some aspects, the controller  140  faults to the return air temperature sensor when a predetermined threshold number (e.g., 50%, or according to a desired configuration) of remote sensors  150  is unavailable. 
     By way of example, an element, or any portion of an element, or any combination of elements (e.g., the controller  142  or other components of the HVAC system  100 ) may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. 
     Accordingly, in one or more example aspects, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.