SENSOR CALIBRATION FOR HEATING, VENTILATION, AND/OR AIR CONDITIONING SYSTEM

Description

BACKGROUND

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

Embodiments of the present disclosure are directed to sensor calibration for heating, ventilation, and/or air conditioning (HVAC) systems configured to operate with reduced energy consumption and reduced greenhouse gas emissions.

A heating, ventilation, and/or air conditioning (HVAC) system may be used to thermally regulate an environment, such as a space within a building, home, or other structure. The HVAC system generally includes a vapor compression system having heat exchangers, such as a condenser and an evaporator, which transfer thermal energy between the HVAC system and the environment. Typically, a compressor is fluidly coupled to a refrigerant circuit of the vapor compression system and is configured to circulate a working fluid (e.g., refrigerant) between the condenser and the evaporator. In some HVAC units, one or more components are controlled based on a temperature of the working fluid in the system. To detect a working fluid temperature, one or more sensors may be disposed along a working fluid path within the system. Unfortunately, traditional HVAC units may be susceptible to undesirable variations in temperature readings from sensors.

SUMMARY

A summary of certain embodiments disclosed herein is set forth below. It should be noted that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

In an embodiment, a method for sensor calibration in a heating, ventilation, and air-conditioning system (HVAC system) includes receiving data indicative of a detected calibration parameter of a working fluid of the HVAC system in an idle state and determining a saturation parameter of the working fluid with a controller of the HVAC system based on the detected calibration parameter and saturation parameter data. The method further includes receiving a first detected parameter from a sensor of the HVAC system, comparing the saturation parameter to the first detected parameter and determining a deviation between the saturation parameter and the first detected parameter. The method further includes receiving a second detected parameter of the working fluid from the sensor of the HVAC system, with the HVAC system in an operating state, and adjusting the second detected parameter using the deviation to determine an adjusted second detected parameter of the working fluid.

In another embodiment, a heat pump for HVAC system includes a working fluid circuit, a first conduit of the working fluid circuit, where the first conduit extends between a first heat exchanger and a second heat exchanger of the working fluid circuit and a compressor disposed along the working fluid circuit, where the compressor may direct a working fluid along the working fluid circuit. The heat pump also may include one or more sensors disposed along the working fluid circuit, where the one or more sensors are configured to detected one or more parameters of the working fluid and a controller communicatively coupled to the one or more sensors. The controller may determine a saturation parameter of a working fluid of the HVAC system based on a calibration parameter detected during an idle state of the heat pump and receive a first detected parameter from a sensor of the one or more sensors. The controller may further compare the saturation parameter to the first detected parameter, determine a deviation between the saturation parameter and the first detected parameter and receive a second detected parameter of the working fluid in an operating sate of the heat pump from the sensor. The controller may further adjust the second detected parameter using the deviation to determine an adjusted second detected parameter of the working fluid.

In a further embodiment, a method for sensor calibration includes receiving, in an idle state of a heat pump, a first detected parameter of a working fluid of the heat pump from a first sensor and determining a saturation parameter of a working fluid of the heat pump based on the first detected parameter and a type of the working fluid. The method further includes receiving, in the idle state of the heat pump, a second detected parameter from a second sensor of the heat pump, comparing the saturation parameter to the second detected parameter, and determining a deviation between the saturation parameter and the second detected parameter. The method further includes receiving, in an operating state of the heat pump, a third detected parameter of the working fluid from the second sensor of the heat pump and adjusting the third detected parameter using the deviation to determine an adjusted third detected parameter of the working fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which:

FIG. 1 is a perspective view of an embodiment of a building incorporating a heating, ventilation, and/or air conditioning (HVAC) system in a commercial setting, in accordance with an aspect of the present disclosure;

FIG. 2 is a perspective view of an embodiment of a packaged HVAC unit, in accordance with an aspect of the present disclosure;

FIG. 3 is a perspective view of an embodiment of a split, residential HVAC system, in accordance with an aspect of the present disclosure;

FIG. 4 is a schematic diagram of an embodiment of a vapor compression system used in an HVAC system, in accordance with an aspect of the present disclosure;

FIG. 5 is a schematic diagram of an embodiment of a portion of an HVAC system including a heat pump system, in accordance with an aspect of the present disclosure; and

FIG. 6 is a flow diagram of an embodiment of a method for sensor calibration, in accordance with an aspect of the present disclosure.

DETAILED DESCRIPTION

One or more specific embodiments of the present disclosure will be described below. These described embodiments are examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers’ specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

As used herein, the terms “approximately,” “generally,” and “substantially,” and so forth, are intended to convey that the property value being described may be within a relatively small range of the property value, as those of ordinary skill would understand. For example, when a property value is described as being “approximately” equal to (or, for example, “substantially similar” to) a given value, this is intended to mean that the property value may be within +/- 5%, within +/- 4%, within +/- 3%, within +/- 2%, within +/- 1%, or even closer, of the given value. Similarly, when a given feature is described as being “substantially parallel” to another feature, “generally perpendicular” to another feature, and so forth, this is intended to mean that the given feature is within +/- 5%, within +/- 4%, within +/- 3%, within +/- 2%, within +/- 1%, or even closer, to having the described nature, such as being parallel to another feature, being perpendicular to another feature, and so forth. Further, it should be understood that mathematical terms, such as “planar,” “slope,” “perpendicular,” “parallel,” and so forth are intended to encompass features of surfaces or elements as understood to one of ordinary skill in the relevant art, and should not be rigidly interpreted as might be understood in the mathematical arts. For example, a “planar” surface is intended to encompass a surface that is machined, molded, or otherwise formed to be substantially flat or smooth (within related tolerances) using techniques and tools available to one of ordinary skill in the art. Similarly, a surface having a “slope” is intended to encompass a surface that is machined, molded, or otherwise formed to be oriented at an angle (e.g., incline) with respect to a point of reference using techniques and tools available to one of ordinary skill in the art.

As briefly discussed above, a heating, ventilation, and/or air conditioning (HVAC) system may be used to thermally regulate a space within a building, home, or other suitable structure. For example, the HVAC system may include a vapor compression system that transfers thermal energy between a working fluid, such as a refrigerant, and a fluid to be conditioned, such as air. The vapor compression system includes heat exchangers, such as a condenser and an evaporator, which are fluidly coupled to one another via one or more conduits of a working fluid loop or circuit. A compressor may be used to circulate the working fluid through the conduits and other components of the working fluid circuit (e.g., an expansion device) and, thus, enable the transfer of thermal energy between components of the working fluid circuit (e.g., between the condenser and the evaporator) and one or more thermal loads (e.g., an environmental air flow, a supply air flow). Additionally or alternatively, the HVAC system may include a heat pump (e.g., a heat pump system) having a first heat exchanger (e.g., a heating and/or cooling coil, an indoor coil, the evaporator) positioned within the space to be conditioned, a second heat exchanger (e.g., a heating and/or cooling coil, an outdoor coil, the condenser) positioned in or otherwise fluidly coupled to an ambient environment (e.g., the atmosphere), and a pump (e.g., the compressor) configured to circulate the working fluid (e.g., refrigerant) between the first and second heat exchangers to enable heat transfer between the thermal load and the ambient environment, for example.

The heat pump system may be controlled based on one or more parameters of the working fluid at various positions along the working fluid circuit. For example, the heat pump system may comprise a controller communicatively coupled to one or more sensors disposed along the working fluid circuit, where the sensors are configured to detect a parameter of the working fluid (e.g. temperature, pressure) during various stages of operation. Based on the detected parameter of the working fluid, the controller may adjust or actuate one or more components of the heat pump system. As an example, based on a detected temperature and/or pressure of the working fluid at the compressor outlet and/or inlet (e.g., suction, discharge), the controller may actuate one or more electronic devices (e.g., electronic expansion valves) to increase the efficiency of the heat pump system. Actuation based on sensor readings is not limited to heat pumps, and other advanced HVAC systems may also utilize similar methods. Unfortunately, sensors within HVAC systems may be susceptible to undesirable variation between sensors and sensor drift.

Accordingly, embodiments of the present disclosure relate to calibration systems and methods configured to reduce undesired sensor variation and sensor drift. For example, present embodiments are related to calculating a saturation temperature of a known working fluid within the working fluid circuit of an HVAC system during an idle time (e.g., suspended state after a sufficient period of inactivity for stabilization, which may be defined by a set time or detection of other conditions). That is, upon a determination that the HVAC system is in the idle state, the controller of the HVAC system may perform one or more determination or calculations based on the type of working fluid, and the pressure of the working fluid to determine a saturation temperature. As will be appreciated, during an idle state of the heat pump system, the working fluid may be in the saturation state. Further, during the idle state of the HVAC system, the working fluid may include a substantially constant temperature at all positions within the working fluid circuit. Upon determination of the saturation temperature, the controller may compare the saturation temperature to a temperature as detected by a respective temperature sensor to determine a deviation. For example, the deviation may be the saturation temperature subtracted from the detected temperature or vice versa.

As will be appreciated, the deviation may be indicative of a sensor drift or other sensor fault. During an operating mode of the HVAC system (e.g., heating, cooling), the controller may receive one or more detected temperatures from one or more sensors which may be inaccurate or unrepresentative of the true temperature of the working fluid. The controller may adjust the detected temperature using the deviation previously determined and stored within a memory device of the controller. For example, the deviation (e.g., -1^oF) may be added to the detected temperature (e.g., 82^oF) by processing circuitry of the controller to determine an adjusted temperature or calibrated temperature (e.g., 81^oF). The controller may then use the adjusted temperature to determine HVAC system parameters and/or control one or more components of the HVAC system.

Although the method is described above as relating to temperature sensors and temperature detection, it will be appreciated a similar method may be performed in calibrating pressure sensors of the HVAC system. For example, a saturation pressure may be determined based on the type of working fluid, and the temperature of the working fluid detected during the idle state of the HVAC system to determine a saturation pressure during the idle state. The controller may compare, during the idle state, the saturation pressure to a detected pressure from a pressure sensor disposed on the working fluid circuit to determine a deviation (e.g., pressure deviation). With the deviation, in an operating mode of the HVAC system, the controller may determine an adjusted pressure by adding the deviation to the detected pressure. In this way, the adjusted pressure may experience a reduced effect or may not be affected by sensor drifts or other sensor faults.

It should be understood that the present disclosure related to systems and methods of sensor calibration is non-limiting, and may be applied to any HVAC system and or component of an HVAC system. For example, embodiments of the present disclosure relate to systems and methods for sensor calibration for heat pumps and other advanced HVAC systems.

Turning now to the drawings, FIG. 1 illustrates an embodiment of a heating, ventilation, and/or air conditioning (HVAC) system for environmental management that employs one or more HVAC units in accordance with the present disclosure. As used herein, an HVAC system includes any number of components configured to enable regulation of parameters related to climate characteristics, such as temperature, humidity, air flow, pressure, air quality, and so forth. For example, an “HVAC system” as used herein is defined as conventionally understood and as further described herein. Components or parts of an “HVAC system” may include, but are not limited to, all, some of, or individual parts such as a heat exchanger, a heater, an air flow control device, such as a fan, a sensor configured to detect a climate characteristic or operating parameter, a filter, a control device configured to regulate operation of an HVAC system component, a component configured to enable regulation of climate characteristics, or a combination thereof. An “HVAC system” is a system configured to provide such functions as heating, cooling, ventilation, dehumidification, pressurization, refrigeration, filtration, or any combination thereof. The embodiments described herein may be utilized in a variety of applications to control climate characteristics, such as residential, commercial, industrial, transportation, or other applications where climate control is desired.

In the illustrated embodiment, a building 10 is air conditioned by a system that includes an HVAC unit 12 with a reheat system in accordance with present embodiments. The building 10 may be a commercial structure or a residential structure. As shown, the HVAC unit 12 is disposed on the roof of the building 10; however, the HVAC unit 12 may be located in other equipment rooms or areas adjacent the building 10. The HVAC unit 12 may be a single package unit containing other equipment, such as a blower, integrated air handler, and/or auxiliary heating unit. In other embodiments, the HVAC unit 12 may be part of a split HVAC system, such as the system shown in FIG. 3, which includes an outdoor HVAC unit 58 and an indoor HVAC unit 56.

The HVAC unit 12 is an air cooled device that implements a refrigeration cycle to provide conditioned air to the building 10. Specifically, the HVAC unit 12 may include one or more heat exchangers across which an air flow is passed to condition the air flow before the air flow is supplied to the building. In the illustrated embodiment, the HVAC unit 12 is a rooftop unit (RTU) that conditions a supply air stream, such as environmental air and/or a return air flow from the building 10. After the HVAC unit 12 conditions the air, the air is supplied to the building 10 via ductwork 14 extending throughout the building 10 from the HVAC unit 12. For example, the ductwork 14 may extend to various individual floors or other sections of the building 10. In certain embodiments, the HVAC unit 12 may be a heat pump that provides both heating and cooling to the building with one refrigeration circuit configured to operate in different modes. In other embodiments, the HVAC unit 12 may include one or more refrigeration circuits for cooling an air stream and a furnace for heating the air stream.

A control device 16, one type of which may be a thermostat, may be used to designate the temperature of the conditioned air. The control device 16 also may be used to control the flow of air through the ductwork 14. For example, the control device 16 may be used to regulate operation of one or more components of the HVAC unit 12 or other components, such as dampers and fans, within the building 10 that may control flow of air through and/or from the ductwork 14. In some embodiments, other devices may be included in the system, such as pressure and/or temperature transducers or switches that sense the temperatures and pressures of the supply air, return air, and so forth. Moreover, the control device 16 may include computer systems that are integrated with or separate from other building control or monitoring systems, and even systems that are remote from the building 10.

FIG. 2 is a perspective view of an embodiment of the HVAC unit 12. In the illustrated embodiment, the HVAC unit 12 is a single package unit that may include one or more independent vapor compression circuits and components that are tested, charged, wired, piped, and ready for installation. The HVAC unit 12 may provide a variety of heating and/or cooling functions, such as cooling only, heating only, cooling with electric heat, cooling with dehumidification, cooling with gas heat, or cooling with a heat pump. As described above, the HVAC unit 12 may directly cool and/or heat an air stream provided to the building 10 to condition a space in the building 10.

As shown in the illustrated embodiment of FIG. 2, a cabinet 24 encloses the HVAC unit 12 and provides structural support and protection to the internal components from environmental and other contaminants. In some embodiments, the cabinet 24 may be constructed of galvanized steel and insulated with aluminum foil faced insulation. Rails 26 may be joined to the bottom perimeter of the cabinet 24 and provide a foundation for the HVAC unit 12. In certain embodiments, the rails 26 may provide access for a forklift and/or overhead rigging to facilitate installation and/or removal of the HVAC unit 12. In some embodiments, the rails 26 may fit into “curbs” on the roof to enable the HVAC unit 12 to provide air to the ductwork 14 from the bottom of the HVAC unit 12 while blocking elements such as rain from leaking into the building 10.

The HVAC unit 12 includes heat exchangers 28 and 30 in fluid communication with one or more vapor compression circuits. Tubes within the heat exchangers 28 and 30 may circulate a working fluid (e.g., a refrigerant), such as R-410A, R-407, R-134a, R-1234ze, R1233zd, R-32, hydrofluoro olefin (HFO), “natural” refrigerants like ammonia (NH3), R-717, carbon dioxide (CO2), R-744, or hydrocarbon based refrigerants, water vapor, or any other suitable working fluid through the heat exchangers 28 and 30. As will be appreciated, different working fluid may include different saturation properties depending on chemical composition and mixture composition. The tubes may be of various types, such as multichannel tubes, conventional copper or aluminum tubing, and so forth. Together, the heat exchangers 28 and 30 may implement a thermal cycle in which the working fluid undergoes phase changes and/or temperature changes as it flows through the heat exchangers 28 and 30 to produce heated and/or cooled air. For example, the heat exchanger 28 may function as a condenser where heat is released from the working fluid to ambient air, and the heat exchanger 30 may function as an evaporator where the working fluid absorbs heat to cool an air stream. In other embodiments, the HVAC unit 12 may operate in a heat pump mode where the roles of the heat exchangers 28 and 30 may be reversed. That is, the heat exchanger 28 may function as an evaporator and the heat exchanger 30 may function as a condenser. In further embodiments, the HVAC unit 12 may include a furnace for heating the air stream that is supplied to the building 10. While the illustrated embodiment of FIG. 2 shows the HVAC unit 12 having two of the heat exchangers 28 and 30, in other embodiments, the HVAC unit 12 may include one heat exchanger or more than two heat exchangers.

The heat exchanger 30 is located within a compartment 31 that separates the heat exchanger 30 from the heat exchanger 28. Fans 32 draw air from the environment through the heat exchanger 28. Air may be heated and/or cooled as the air flows through the heat exchanger 28 before being released back to the environment surrounding the HVAC unit 12. A blower assembly 34, powered by a motor 36, draws air through the heat exchanger 30 to heat or cool the air. The heated or cooled air may be directed to the building 10 by the ductwork 14, which may be connected to the HVAC unit 12. Before flowing through the heat exchanger 30, the conditioned air flows through one or more filters 38 that may remove particulates and contaminants from the air. In certain embodiments, the filters 38 may be disposed on the air intake side of the heat exchanger 30 to prevent contaminants from contacting the heat exchanger 30.

The HVAC unit 12 also may include other equipment for implementing the thermal cycle. Compressors 42 increase the pressure and temperature of the working fluid before the working fluid enters the heat exchanger 28. The compressors 42 may be any suitable type of compressors, such as scroll compressors, rotary compressors, screw compressors, or reciprocating compressors. In some embodiments, the compressors 42 may include a pair of hermetic direct drive compressors arranged in a dual stage configuration 44. However, in other embodiments, any number of the compressors 42 may be provided to achieve various stages of heating and/or cooling. As may be appreciated, additional equipment and devices may be included in the HVAC unit 12, such as a solid-core filter drier, a drain pan, a disconnect switch, an economizer, pressure switches, phase monitors, and humidity sensors, among other things.

The HVAC unit 12 may receive power through a terminal block 46. For example, a high voltage power source may be connected to the terminal block 46 to power the equipment. The operation of the HVAC unit 12 may be governed or regulated by a control board 48. The control board 48 may include control circuitry connected to a thermostat, sensors, and alarms. One or more of these components may be referred to herein separately or collectively as the control device 16. The control circuitry may be configured to control operation of the equipment, provide alarms, and monitor safety switches. Wiring 49 may connect the control board 48 and the terminal block 46 to the equipment of the HVAC unit 12.

FIG. 3 illustrates a residential heating and cooling system 50, also in accordance with present techniques. The residential heating and cooling system 50 may provide heated and cooled air to a residential structure, as well as provide outside air for ventilation and provide improved indoor air quality (IAQ) through devices such as ultraviolet lights and air filters. In the illustrated embodiment, the residential heating and cooling system 50 is a split HVAC system. In general, a residence 52 conditioned by a split HVAC system may include working fluid conduits 54 that operatively couple the indoor unit 56 to the outdoor unit 58. The indoor unit 56 may be positioned in a utility room, an attic, a basement, and so forth. The outdoor unit 58 is typically situated adjacent to a side of residence 52 and is covered by a shroud to protect the system components and to prevent leaves and other debris or contaminants from entering the unit. The working fluid conduits 54 transfer working fluid between the indoor unit 56 and the outdoor unit 58, typically transferring primarily liquid working fluid in one direction and primarily vaporized working fluid in an opposite direction.

When the system shown in FIG. 3 is operating as an air conditioner, a heat exchanger 60 in the outdoor unit 58 serves as a condenser for re-condensing vaporized working fluid flowing from the indoor unit 56 to the outdoor unit 58 via one of the working fluid conduits 54. In these applications, a heat exchanger 62 of the indoor unit functions as an evaporator. Specifically, the heat exchanger 62 receives liquid working fluid, which may be expanded by an expansion device, and evaporates the working fluid before returning it to the outdoor unit 58.

The outdoor unit 58 draws environmental air through the heat exchanger 60 using a fan 64 and expels the air above the outdoor unit 58. When operating as an air conditioner, the air is heated by the heat exchanger 60 within the outdoor unit 58 and exits the unit at a temperature higher than it entered. The indoor unit 56 includes a blower or fan 66 that directs air through or across the indoor heat exchanger 62, where the air is cooled when the system is operating in air conditioning mode. Thereafter, the air is passed through ductwork 68 that directs the air to the residence 52. The overall system operates to maintain a desired temperature as set by a system controller. When the temperature sensed inside the residence 52 is higher than the set point on the thermostat, or the set point plus a small amount, the residential heating and cooling system 50 may become operative to refrigerate additional air for circulation through the residence 52. When the temperature reaches the set point, or the set point minus a small amount, the residential heating and cooling system 50 may stop the refrigeration cycle temporarily. The outdoor unit 58 includes a reheat system in accordance with present embodiments.

The residential heating and cooling system 50 may also operate as a heat pump. When operating as a heat pump, the roles of heat exchangers 60 and 62 are reversed. That is, the heat exchanger 60 of the outdoor unit 58 will serve as an evaporator to evaporate working fluid and thereby cool air entering the outdoor unit 58 as the air passes over the outdoor heat exchanger 60. The indoor heat exchanger 62 will receive a stream of air blown over it and will heat the air by condensing the working fluid.

In some embodiments, the indoor unit 56 may include a furnace system 70. For example, the indoor unit 56 may include the furnace system 70 when the residential heating and cooling system 50 is not configured to operate as a heat pump. The furnace system 70 may include a burner assembly and heat exchanger, among other components, inside the indoor unit 56. Fuel is provided to the burner assembly of the furnace 70 where it is mixed with air and combusted to form combustion products. The combustion products may pass through tubes or piping in a heat exchanger, separate from heat exchanger 62, such that air directed by the blower 66 passes over the tubes or pipes and extracts heat from the combustion products. The heated air may then be routed from the furnace system 70 to the ductwork 68 for heating the residence 52.

FIG. 4 is an embodiment of a vapor compression system 72 that can be used in any of the systems described above. The vapor compression system 72 may circulate a working fluid through a circuit starting with a compressor 74. The circuit may also include a condenser 76, an expansion valve(s) or device(s) 78, and an evaporator 80. The vapor compression system 72 may further include a control panel 82 that has an analog to digital (A/D) converter 84, a microprocessor 86, a non-volatile memory 88, and/or an interface board 90. The control panel 82 and its components may function to regulate operation of the vapor compression system 72 based on feedback from an operator, from sensors of the vapor compression system 72 that detect operating conditions, and so forth.

In some embodiments, the vapor compression system 72 may use one or more of a variable speed drive (VSDs) 92, a motor 94, the compressor 74, the condenser 76, the expansion valve or device 78, and/or the evaporator 80. The motor 94 may drive the compressor 74 and may be powered by the variable speed drive (VSD) 92. The VSD 92 receives alternating current (AC) power having a particular fixed line voltage and fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the motor 94. In other embodiments, the motor 94 may be powered directly from an AC or direct current (DC) power source. The motor 94 may include any type of electric motor that can be powered by a VSD or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor.

The compressor 74 compresses a working fluid vapor and delivers the vapor to the condenser 76 through a discharge passage. In some embodiments, the compressor 74 may be a centrifugal compressor. The working fluid vapor delivered by the compressor 74 to the condenser 76 may transfer heat to a fluid passing across the condenser 76, such as ambient or environmental air 96. The working fluid vapor may condense to a working fluid liquid in the condenser 76 as a result of thermal heat transfer with the environmental air 96. The liquid working fluid from the condenser 76 may flow through the expansion device 78 to the evaporator 80.

The liquid working fluid delivered to the evaporator 80 may absorb heat from another air stream, such as a supply air stream 98 provided to the building 10 or the residence 52. For example, the supply air stream 98 may include ambient or environmental air, return air from a building, or a combination of the two. The liquid working fluid in the evaporator 80 may undergo a phase change from the liquid working fluid to a working fluid vapor. In this manner, the evaporator 80 may reduce the temperature of the supply air stream 98 via thermal heat transfer with the working fluid. Thereafter, the vapor working fluid exits the evaporator 80 and returns to the compressor 74 by a suction line to complete the cycle.

In some embodiments, the vapor compression system 72 may further include a reheat coil. In the illustrated embodiment, the reheat coil is represented as part of the evaporator 80. The reheat coil is positioned downstream of the evaporator heat exchanger relative to the supply air stream 98 and may reheat the supply air stream 98 when the supply air stream 98 is overcooled to remove humidity from the supply air stream 98 before the supply air stream 98 is directed to the building 10 or the residence 52.

It should be appreciated that any of the features described herein may be incorporated with the HVAC unit 12, the residential heating and cooling system 50, or other HVAC systems. Additionally, while the features disclosed herein are described in the context of embodiments that directly heat and cool a supply air stream provided to a building or other load, embodiments of the present disclosure may be applicable to other HVAC systems as well. For example, the features described herein may be applied to mechanical cooling systems, free cooling systems, chiller systems, or other heat pump or refrigeration applications.

To provide context for the following discussion, FIG. 5 is a schematic of an embodiment of a portion of an HVAC system 100 that includes a heat pump 102 (e.g., a heat pump system, reverse cycle heat pump, air source heat pump, an energy efficient heat pump) in accordance with present embodiments. The heat pump 102 may include one or more components of the vapor compression system 72 discussed above and/or may be included in any of the systems described above (e.g., the HVAC unit 12, the heating and cooling system 50). The heat pump 102 includes a first heat exchanger 104 and a second heat exchanger 106 that are fluidly coupled to one another via a working fluid circuit 108 or working fluid loop (e.g., one or more conduits, refrigerant circuit). The first heat exchanger 104 may be in thermal communication with (e.g., fluidly coupled to) a thermal load 110 (e.g., a room, space, and/or device) serviced by the heat pump 102, and the second heat exchanger 106 may be in thermal communication with an ambient environment 112 (e.g., the atmosphere) surrounding the HVAC system 100.

In some embodiments, a first fan 116 (e.g., blower) may direct a first air flow across the first heat exchanger 104 to facilitate heat exchange between working fluid within the first heat exchanger 104 and the thermal load 110, while a second fan 118 may direct a second air flow across the second heat exchanger 106 to facilitate heat exchange between working fluid within the second heat exchanger 106 and the ambient environment 112. One or more expansion devices 120 (e.g., an electronic expansion valve [EEV], a bi-directional expansion valve) may be disposed along the working fluid circuit 108 between the first heat exchanger 104 and the second heat exchanger 106 and may be configured to regulate (e.g., throttle) a flow of working fluid and/or a working fluid pressure differential between the first and second heat exchangers 104, 106. In the illustrated embodiment, the working fluid circuit 108 includes a first expansion device 122 (e.g., indoor expansion device, EEV) disposed along the working fluid circuit 108 proximate the first heat exchanger 104 and a second expansion device 124 (e.g., outdoor expansion device, EEV) disposed along the working fluid circuit 108 proximate the second heat exchanger 106. However, as discussed below, in other embodiments the heat pump 102 may include either the first expansion device 122 or the second expansion device 124.

The heat pump 102 also includes a compressor 130 (e.g., compressor system) disposed along the working fluid circuit 108. The compressor 130 is configured to direct working fluid flow through the first heat exchanger 104, the second heat exchanger 106, and remaining components (e.g., the expansion device(s) 120) that may be fluidly coupled to the working fluid circuit 108. Although one compressor 130 is shown in the illustrated embodiment, the heat pump 102 may include any suitable quantity of compressors 130, such as two, three, four, five, six, or more than six compressors 130. The compressor 130 may be a multi-stage (e.g., two stage) compressor and/or a variable speed compressor. Additionally, the compressor 130 may be a high-side shell compressor, a rotary compressor, a scroll compressor, and/or any other suitable type of compressor. The compressor 130 is configured to receive working fluid (e.g., a primary flow of working fluid) via a suction conduit 132 fluidly coupled to a suction port 134 of the compressor 130 and to discharge working fluid (e.g., compressed working fluid) via a discharge conduit 136 fluidly coupled to a discharge port 138 of the compressor 130.

The compressor 130 may be fluidly coupled to a remainder of the working fluid circuit 108 via a reversing valve 150 (e.g., a switch-over valve). In the illustrated embodiment, the reversing valve 150 includes a first port 152 that is fluidly coupled to the suction conduit 132, a second port 154 that is fluidly coupled to the discharge conduit 136, a third port 156 that is fluidly coupled to a first conduit portion 158 extending to the first heat exchanger 104, and a fourth port 160 that is fluidly coupled to a second conduit portion 162 extending to the second heat exchanger 106. The reversing valve 150 is configured to transition between a first configuration 164, in which the reversing valve 150 fluidly couples the first port 152 and the fourth port 160, and fluidly couples the second port 154 and the third port 156, and a second configuration, in which the reversing valve 150 fluidly couples the first port 152 and the third port 156, and fluidly couples the second port 154 and the fourth port 160. As such, by transitioning the reversing valve 150, the direction of working fluid 172 may change, altering the heat pump configuration from a heating mode to a cooling mode or vice versa. While the illustrated embodiment depicts a particular direction of flow, one of ordinary skill in the art will understand that the direction will change based on valve configurations.

The expansion devices 120 (e.g., EEVs) of the heat pump 102 may be controlled to further enable more efficient operation of the heat pump 102. For example, the expansion devices 120 may be controlled based on an operating mode of the heat pump 102, based on operating conditions or parameters of the heat pump 102, and/or based on other suitable factors. To this end, the HVAC system 100 includes a controller 220 (e.g., a control system, a thermostat, a control panel, control circuitry) that is communicatively coupled to one or more components of the heat pump 102 (e.g., expansion devices 120) and is configured to monitor, adjust, and/or otherwise control operation of the components of the heat pump 102. For example, one or more control transfer devices, such as wires, cables, wireless communication devices, and the like, may communicatively couple the compressor 130, the expansion device(s) 120, the first and/or second fans 116, 118, the control device 16 (e.g., a thermostat), and/or any other suitable components of the HVAC system 100 to the controller 220. That is, the compressor 130, the expansion device(s) 120, the first and/or second fans 116, 118, and/or the control device 16 may each have one or more communication components that facilitate wired or wireless (e.g., via a network) communication with the controller 220. In some embodiments, the communication components may include a network interface that enables the components of the HVAC system 100 to communicate via various protocols such as EtherNet/IP, ControlNet, DeviceNet, or any other communication network protocol. Alternatively, the communication components may enable the components of the HVAC system 100 to communicate via mobile telecommunications technology, Bluetooth®, near-field communications technology, and the like. As such, the compressor 130, the expansion device(s) 120, the first and/or second fans 116, 118, and/or the control device 16 may wirelessly communicate data between each other. In other embodiments, operational control of certain components of the heat pump 102 may be regulated by one or more relays or switches (e.g., a 24 volt alternating current [VAC] relay).

In some embodiments, the controller 220 may be a component of or may include the control panel 82. In other embodiments, the controller 220 may be a standalone controller, a dedicated controller, or another suitable controller included in the HVAC system 100. In any case, the controller 220 is configured to control components of the HVAC system 100 in accordance with the techniques discussed herein. The controller 220 includes processing circuitry 222, such as a microprocessor, which may execute software for controlling the components of the HVAC system 100. The processing circuitry 222 may include multiple microprocessors, one or more “general-purpose” microprocessors, one or more special-purpose microprocessors, and/or one or more application specific integrated circuits (ASICS), or some combination thereof. For example, the processing circuitry 222 may include one or more reduced instruction set (RISC) processors.

The controller 220 may also include a memory device 224 (e.g., a memory) that may store information, such as instructions, control software, look up tables, configuration data, etc. The memory device 224 may include a volatile memory, such as random access memory (RAM), and/or a nonvolatile memory, such as read-only memory (ROM). The memory device 224 may store a variety of information and may be used for various purposes. For example, the memory device 224 may store processor-executable instructions including firmware or software for the processing circuitry 222 to execute, such as instructions for controlling components of the HVAC system 100 (e.g., expansion devices 120). In some embodiments, the memory device 224 is a tangible, non-transitory, machine-readable-medium that may store machine-readable instructions for the processing circuitry 222 to execute. The memory device 224 may include ROM, flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. The memory device 224 may store data, instructions, and any other suitable data.

In some embodiments, one or more of the sensors 230 may be disposed along the discharge conduit 136 and may be configured to detect a temperature and/or a pressure of working fluid discharged by the compressor 130. Similarly, one or more of the sensors 230 may be disposed along the suction conduit 132 and may be configured to detect a temperature and/or a pressure of working fluid entering the compressor 130 via the suction port 134. Further, one or more of the sensors 230 may be disposed adjacent to the first heat exchanger 104 and may be configured to detect a temperature and/or a pressure of working fluid entering the first heat exchanger 104 and/or exiting the first heat exchanger 104. Similarly, one or more of the sensors 230 may be disposed adjacent to the second heat exchanger 106 and may be configured to detect a temperature and/or a pressure of working fluid entering the second heat exchanger 106 and/or exiting the second heat exchanger 106. Sensors 230 may further be disposed at any suitable location along the working fluid circuit 108. As will be appreciated, sensors 230 and/or additional sensors may be utilized as a part of any of the previously illustrated embodiments (e.g., FIGS. 1-4).

As mentioned above, the controller 220 may be configured to regulate operation of the expansion devices 120 based on various factors, such as an operating mode of the heat pump 102 (e.g., heating mode, cooling mode) and/or operating parameters or conditions of the heat pump 102 (e.g., of components of the heat pump 102). In some embodiments, the controller 220 may regulate operation of the expansion devices 120 according to a selected control sequence, which may be based on the heat pump 102 operating mode and/or operating conditions. In any situation, the controller 220 may use a detected parameter (e.g., temperature and/or pressure) from the one or more sensors 230 to control a component (e.g., expansion devices 120) of the heating pump 102.

As discussed briefly above, the controller 220 may be configured to adjust (e.g., correct, calibrate) a detected parameter of the one or more sensors 230 using a saturation parameter (e.g., saturation temperature, saturation pressure). For example, the controller 220 may be configured to determine a saturation temperature of the working fluid of the working fluid circuit 108 during an idle state of the heat pump 102. The idle state may be a state where the heat pump 102 (e.g., compressor 130) is not operating in a heating or cooling mode (e.g., suspended state) after a sufficient period of inactivity. As will be appreciated, in the idle state, the working fluid of the working fluid circuit 108 may be a constant temperature throughout, that is, the working fluid may be the same temperature at any point along the working fluid circuit 108. Further, as will be appreciated, the temperature of the working fluid in the idle state of the heat pump 102 may be at the saturation temperature of the working fluid. Therefore, the temperature of the working fluid (e.g., saturation temperature), during the idle state, may be determined (e.g., calculated) without detection of the temperature via a sensor (e.g., sensors 230). That is, the memory device 224 may include one or more algorithms to be performed by the processing circuitry 222 to determine a saturation temperature of the working fluid within the working fluid circuit 108. The one or more algorithms may include parameters related to the saturation pressure and the type of working fluid (e.g., composition, mixture composition). During an idle state of the heat pump 102 (as detected based on function and time or other conditions), the controller 220 may receive a detected pressure (e.g., detected calibration pressure) from a sensor where the controller 220 may then perform the one or more algorithms to determine a saturation temperature, based on the received detected pressure and the type of working fluid (e.g., saturation parameter data).

In some embodiments, the memory device 224 may store empirical data or correlations, such as lookup tables or one or more charts (e.g., pressure temperature charts (e.g., PT charts)) to be utilized by the processing circuitry 222 to determine a saturation temperature of the working fluid within the working fluid circuit 108. Where charts are employed, each chart of the one or more charts may be specific to the type or working fluid and each chart may be used to determine a saturation temperature from a saturation pressure (e.g., detected pressure). As such, the memory device 224 may include multiple charts corresponding to multiple types of working fluids. In some instances, the saturation temperature may be extrapolated from data available within the one or more charts. In any situation, during the idle state of the heat pump 102, the controller 220 may receive a detected pressure from a sensor where the controller 220 may utilize the detected pressure, and the one or more respective charts, to determine a saturation temperature. One of ordinary skill in the art will understand that charts include data correlations, whether viewable as a chart or merely stored as data.

Upon determining the saturation temperature, the controller 220, in the idle state of the heat pump, may be operable to compare the determined saturation temperature to a detected temperature from a sensor of the one or more sensors 230. For example, the controller 220 may receive data (e.g., resistance value) indicative of a detected temperature from the sensor of the one or more sensors 230. The controller 220 may compare the detected temperature from the sensor to the saturation temperature and determine a deviation (e.g., temperature deviation) between the two values. As an example, a detected temperature of 84^oF and a saturation temperature of 83^oF may have a deviation of -1^oF. The deviation may be stored within the memory device 224 of the controller 220 to be retrieved during operation of the heat pump 102.

After determining the deviation, the deviation may be used by the controller 220 to calibrate the one or more sensors 230 of the heat pump 102 during operation (e.g., heating, cooling). That is, during operation of the heat pump 102 (e.g., heating, cooling) the controller 220 may receive one or more signals indicative of a detected temperature from the sensor of the one or more sensors 230. The controller 220 may adjust (e.g., calibrate) the detected temperature using the deviation to determine an adjusted temperature (e.g., calibrated temperature). For example, the controller 220 may receive a signal indicative of a detected temperature of 79^oF from the sensor of the one or more sensors 230 during operation of the heat pump 102. The controller 220 may then retrieve the deviation (e.g., -1^oF) from the memory device 224 to be applied (e.g., added) to the detected temperature (e.g., 79^oF) to determine the adjusted detected temperature (e.g., 78^oF).

In some embodiments, the deviation may be specific to a respective sensor of the one or more sensors 230. A respective deviation may be determined using the methods disclosed herein for each sensor of the one or more sensors 230 such that each sensor may be calibrated using its own respective deviation. For example, in an idle state of the heat pump 102, a first deviation may be determined by the controller 220 using the saturation temperature and a first detected sensor from a first sensor. Further, in the idle state of the heat pump 102, a second deviation may be determined by the controller 220 using the saturation temperature and a second detected sensor from a second sensor. During operation of the heat pump 102, upon receiving a signal indicative of a first detected temperature from the first sensor, the controller 220 may adjust (e.g., calibrate) the first detected temperature using the first deviation to determine a first adjusted detected temperature, such as, by adding the first deviation to the first detected temperature. Similarly, during operation of the heat pump 102, upon receiving a signal indicative of a second detected temperature from the second sensor, the controller 220 may adjust (e.g., calibrate) the second detected temperature using the second deviation to determine a second adjusted detected temperature, such as, by adding the second deviation to the second detected temperature. In this way, sensor faults specific to a respective sensor may be calibrated accordingly, improving control of the heat pump 102.

In some embodiments, the deviation may apply to more than one sensor. A deviation may be determined using the methods disclosed herein for more than one sensor such that two or more sensors may be calibrated using a single respective deviation. For example, in an idle state of the heat pump 102, a deviation may be determined by the controller 220 using the saturation temperature and a detected temperature from one or more sensors. In some embodiments, the detected temperature in the idle state may be an average of detected temperatures from the one or more sensors 230. In some embodiments, the detected temperature may not be from a sensor disposed on the working fluid circuit 108 and may be instead an additional sensor, such as a technician’s thermometer. During operation of the heat pump 102, upon receiving a signal indicative of a first detected temperature from a first sensor, the controller 220 may adjust (e.g., calibrate) the first detected temperature using the deviation to determine a first adjusted detected temperature, such as, by adding the deviation to the first detected temperature. Similarly, during operation of the heat pump 102, upon receiving a signal indicative of a second detected temperature from a second sensor, the controller 220 may adjust (e.g., calibrate) the second detected temperature using the deviation to determine a second adjusted detected temperature, such as, by adding the deviation to the second detected temperature. In this way, the controller 220 may calibrate a subset of the one or more sensors 230 using a common deviation, reducing common sensor drift between sensors of the one or more sensors 230.

In any case, the adjusted detected temperature may be utilized by the controller 220 to make one or more determinations and/or perform one or more actions. In some embodiments, the controller 220 may adjust (e.g., regulate, initiate, switch, engage) and/or suspend one or more components of the heat pump 102 based on the adjusted detected temperature. In some embodiments, the controller 220 may compare the adjusted detected temperature to a threshold temperature, where then the controller 220 may adjust and/or suspend operation of one or more components of the heat pump 102 based on a comparison of the adjusted detected temperature to the threshold temperature. For example, upon a determination by the controller 220 that the adjusted detected temperature is greater than the threshold temperature, the controller 220 may send a signal to one or more components of the heat pump 102 (e.g., electronic devices 120) to actuate the component. By utilizing the adjusted detected temperature, components of the heat pump 102 may be controlled with increased accuracy, increasing overall efficiency.

As discussed briefly above, the systems and methods described herein may be utilized to calibrate pressure sensors as well as temperature sensors. For example, the memory device 224 of the controller may store empirical data or correlations, such as lookup tables or one or more charts (e.g., pressure temperature charts (e.g., PT charts)) and/or one or more algorithms to be utilized/performed by the processing circuitry 222 to determine a saturation pressure of the working fluid within the working fluid circuit 108 in the idle state of the heat pump 102. Upon determining the saturation pressure, the controller 220 may compare the determined saturation pressure to a detected pressure from the one or more sensors 230 to determine a deviation (e.g., pressure deviation) in the idle state of the heat pump 102. After determining the deviation, controller 220 may calibrate or adjust the one or more sensors 230 of the heat pump 102 during operation of the heat pump 102. That is, during operation of the heat pump 102 (e.g., heating, cooling), the controller 220 may adjust (e.g., calibrate) a detected pressure using the deviation to determine an adjusted pressure (e.g., calibrated pressure). The adjusted detected pressure may be utilized by the controller 220 to make one or more determinations and/or perform one or more actions related to the heat pump 102. In some embodiments, the controller 220 may adjust and/or suspend operation of one or more components of the heat pump 102 based on the adjusted detected pressure. In some embodiments, the controller 220 may compare the adjusted detected pressure to a threshold pressure, where the controller 220 may adjust and/or suspend operation of one or more components of the heat pump 102 based on a comparison of the adjusted detected pressure to the threshold pressure. It should be noted that the systems and methods related to pressure sensing calibration disclosed herein may be substantially similar to the systems and methods related to temperature sensing calibration disclosed herein.

In some embodiments, the deviation (e.g., pressure deviation) may be used to detect a working fluid leak within the working fluid circuit 108. For example, as discussed above, during the idle state of the heat pump 102, the controller 220 may compare the determined saturation pressure to the detected pressure from the one or more sensors 230 to determine the deviation. Upon determining the deviation, the controller 220 may compare the absolute value of the deviation to a threshold. A deviation between the saturation pressure and the detected pressure that is beyond a threshold may indicate a leak of the working fluid from the working fluid circuit 108. In some embodiments, the controller 220 may compare a previous deviation to a current deviation to determine a potential leak. For example, after determining a first deviation in a manner described above, the controller 220 may store the first deviation within the memory device 224. Upon determination of a second deviation, after a subsequent idle period, the controller 220 may be configured to compare the second deviation to the first deviation to determine a potential leak. That is, systems and methods for leak detection disclosed herein may include an iterative process, comparing a current deviation to the previous deviation to determine system faults. In any case, upon determining a leak condition by one of more of the methods described above, the controller 220 may perform one or more leak mitigation measures. For example, upon determining the absolute value of the deviation is greater than the threshold, the controller 220 may send a signal to one or more components of the heat pump 102 to alter or suspend operation. Further, upon determining the absolute value of the deviation is greater than the threshold, the controller 220 may send a notification (e.g., alert) to an operator of the heat pump 102, warning of a potential leakage.

The controller 220 may be configured to determine the idle state of the heat pump 102 prior to determining a saturation parameter of the working fluid. As used herein, the idle state of the heat pump 102 may be a state or condition of the heat pump 102 where the working fluid is at its saturation state and has substantially constant saturation parameters (e.g., saturation temperature, saturation pressure) throughout the working fluid circuit 108. In some embodiments, the controller 220 may determine an idle state has been reached when a period of inactivity (e.g., preset period of inactivity after compressor 130 shutdown, variable period of inactivity after compressor 130 shutdown) has passed or by detecting other conditions associated with an idle state (e.g., a temperature relative to ambient). For example, the controller 220 may receive a call for shut down of the compressor 130, where the controller 220 may send a signal to the compressor 130, suspending operation. After the period of inactivity of the compressor 130 (e.g., 5 minutes, 10 minutes) has been met, the controller 220 may determine an idle state has been reached and may determine the saturation temperature and/or temperature of the heat pump 102 via the methods disclosed herein. In this way, the working fluid within the working fluid circuit 108 may be uniform in temperature, enabling increased accuracy in calibration. Further, calibrating after the period of inactivity may enable the working fluid to transition to its saturation state, enabling calculations of the saturation temperature and/or pressure.

In some embodiments, the controller 220 may be configured to compare deviations (e.g., pressure deviations, temperature deviations) of different sensors of the one or more sensors 230. For example, the controller 220 may be configured to determine a first deviation from a first sensor and a second deviation from a second sensor in a manner described above. Upon determining the first and second deviations, the controller 220 may be configured to compare the two deviations to determine a deviation difference. Further, based on the deviation difference, the controller 220 may be configured to perform one or more actions, such as, alerting the operator of the heat pump 102 of a potential non-equalized system. In this way, the disclosed calibration techniques may reduce and/or prevent non-equalized sensor systems.

Although the above systems and methods are discussed in view of a heat pump (e.g., heat pump 102) it will be appreciated that the systems and methods disclosed herein may be used in other HVAC systems. For example, the disclosed systems and methods may be used with any advanced HVAC systems having one or more sensors detecting one or more parameters of working fluid.

With the foregoing in mind, FIG. 6 is a flow chart of an embodiment of a method 300 (e.g., calibration sequence) for operating the heat pump 102. As will be appreciated, the method 300 may be performed by the controller 220. For example, computer executable instructions or code for performing the method 300 may be stored on the memory device 224, and the processing circuitry 222 may execute the instructions to perform the method 300. In some embodiments, one or more steps of the method 300 may be performed by another controller of the HVAC system 100. In additional or alternative embodiments, multiple components or systems may perform the steps of the method 300. It should also be noted that additional steps may be performed with respect to the depicted method 300. Moreover, certain steps of the method 300 may be removed, modified, and/or performed in a different order. Further still, the steps of the method 300 may be performed in any suitable relation with one another, such as in response to one another and/or in parallel with one another.

At block 304, the controller 220 may determine an idle state of the HVAC system. As discussed above, certain steps of method 300 may be performed during an idle state of the HVAC system (e.g., heat pump). In this way, the working fluid within the working fluid circuit may be at the saturation state and comprise constant parameters (e.g., pressure, temperature) at all points of the working fluid circuit. As such, the controller 220 may determine the HVAC system is in an idle state, for example, after a determination that the HVAC system has suspended operation for a period (e.g., a preset period, a variable period) of inactivity. The period of inactivity may be a period after the initial shut down of the heat pump (e.g., compressor) sufficient to transition the working fluid to a saturation state. In some embodiments, the period of inactivity may be fixed or preset, such as 5 minutes, 10 minutes, 15 minutes, etc., after shutdown of the HVAC system. In some embodiments, the period of inactivity may be variable, and based on one or more parameters, such as, a parameter of the HVAC system, an ambient condition, and/or another suitable parameter.

In any case, after a determination by the controller 220 that the HVAC system is in the idle state, the controller 220 may determine a deviation during the idle state of the HVAC system at block 308. As described herein, the controller 220 may determine (e.g., calculate, extrapolate) a saturation parameter (e.g., temperature, pressure) of the working fluid by one or more of the methods described above. For example, the controller (e.g., memory device 224) may include charts configured to be used by a processing circuitry 222 of the controller to determine a saturation parameter. The controller 220 may determine the saturation parameter based on a detected calibration parameter (e.g., detected calibration temperature, detected calibration pressure) and saturation parameter data (e.g., data related to a respective PT chart of the working fluid type) in the idle state of the HVAC system. Further, the controller 220 may receive a signal indicative of a detected parameter (e.g., pressure, temperature) from a sensor of the HVAC system during the idle state. The controller 220 may compare the detected parameter to the saturation parameter to determine the deviation. The controller 220 may store the deviation in the memory device 224 to calibrate the sensors during operation of the HVAC system.

At block 312, the controller 220 may receive a detected parameter from a sensor of the one or more sensors during an operational state of the HVAC system. For example, the controller 220 may receive one or more detected parameters, such as temperature or pressure, from one or more sensors disposed at various positions along the working fluid circuit.

At block 316, the controller 220 may calibrate the detected parameter received from one or more sensors to determine an adjusted detected parameter (e.g., adjusted detected temperature, adjusted detected pressure) during the operational state of the HVAC system. For example, the controller 220 may be configured to add the deviation to the detected parameter to calculate the adjusted detected parameter. That is, the memory device 224 of the controller 220 may include an algorithm configured to add the deviation (e.g., deviation previously determined and stored in the memory device 224) to the detected parameter to determine the adjusted detected parameter. In this way, the detected parameter may be calibrated to decrease sensor drifts or other sensor faults, thereby increasing sensor accuracy.

At block 320, the controller 220 may be configured to perform one or more actions based on the adjusted detected parameter. For example, the controller 220 may alter and/or suspend one or more components of the heat pump based on the adjusted detected parameter. Specifically, the controller 220 may compare the adjusted detected parameter to a threshold parameter in order to determine a comparison. The controller 220 may than alter and/or suspend operation of one or more components of the heat pump based on that comparison. Further, the controller 220 may send a notification (e.g., alert) to an operator of the heat pump based on the adjusted detected parameter and/or in response to a comparison of the adjusted detected parameter to the threshold parameter.

It should be appreciated that certain steps of the method 300 may be performed iteratively throughout an operating cycle of the HVAC system. For example, during a first iteration of the HVAC system (e.g., start up, operation, and shut down), a first deviation may be determined and used to calibrate one or more sensors during operation. The HVAC system may then suspend operation, where the method 300 may restart at block 304 to determine a second deviation, which may be different than the first deviation, to be used to calibrate the one or more sensors during operation during the second iteration of HVAC system. In this way, sensor calibration may be utilized with increased accuracy, as a deviation may be obtained after every suspension of the HVAC system. Further, as will be appreciated, method 300 may be performed for pressure sensor calibration and temperature sensor calibration concurrently.

As set forth above, embodiments of the present disclosure may provide one or more technical effects useful for calibrating one or more sensors of an HVAC system. Indeed, implementation of the disclosed calibration systems and methods enable more accurate sensor reading, improving efficiency of the HVAC system. It should be understood that the technical effects and technical problems in the specification are examples and are not limiting. Indeed, it should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.

While only certain features and embodiments have been illustrated and described, many modifications and changes may occur to those skilled in the art, such as variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, such as temperatures and pressures, mounting arrangements, use of materials, colors, orientations, and so forth, without materially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.

Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described, such as those unrelated to the presently contemplated best mode, or those unrelated to enablement. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.

The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function]…” or “step for [perform]ing [a function]…”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).