Method for Operating a Heat Cool System During a Sensor Failure and a System Thereof

The present invention relates to a method for operating a heat cool system during a sensor failure and system thereof.

Generally, in any heating, ventilation, and air Conditioning (HVAC) system, for example a heat cool system, a refrigerant circulates throughout the heat cool system by means of a refrigerant loop. In the refrigerant loop, the refrigerant leaves the evaporator and enters a compressor where the pressure of the refrigerant is increased. The compressed refrigerant leaves the compressor and enters a condenser where it is condensed from a vapor to a liquid refrigerant by heat exchange. The liquid refrigerant is then returned, by means of an expansion device, to the evaporator to continue the cycle through the refrigerant. A four-way valve located at an outlet of the compressor controls the path of refrigerant and in turn controls whether refrigerant is used for heating application or for cooling applications. In such a conventional system, a plurality of sensors temperatures and pressure sensors are employed for operating during both cooling and heating applications. However, such sensors have significant inherent limitations. Such sensors during their operation cycle may fail to function leading to the stopping of the system. Further, it has been observed that stopping the system in some instances, for example in places where the temperatures are freezing, failure of working of heating application of the heat cool system may often lead to a life-threatening situation since the ambient temperature is very low. Further, in cases where the system is not stopped, there exists no protection for the system and the various components of the system.

Therefore, there is a need to provide a method and system for operating the heat cool system during the sensor failure which overcomes one or more of the aforementioned problems.

Accordingly, an aspect of the present invention discloses a method of operating a heat cool system, comprising the steps of storing, by a controller, a plurality of first predetermined values; determining and storing by the controller, a plurality of second predetermined values obtained from a plurality of sensors, after an initial startup of the heat cool system; determining, a status of the plurality of sensors in communication with the controller located within the heat cool system; determining, a single or multi-sensor failure else determining a plurality of real-time values obtained by the plurality of sensors; determining, the heat cool system run status based on a multi-sensor failure matrix triggered on determining the multi-sensor failure; determining, in the event of single or multi-sensor failure, a virtual value of at least a failed sensor based on the plurality of first and second predetermined values; and comparing if the determined virtual value of at least the failed sensor satisfies an interlock value matrix and obtaining, determining a real-time virtual value of at least the failed sensor based on the interlock value matrix for running heat and cool refrigeration cycles without stopping the heat cool system even in the event of single or multi-sensor failure.

According to another aspect, the present invention discloses a heat cool system comprising an outdoor unit equipped with an inverter-driven compressor; an indoor unit; evaporator and a condenser; an expansion device; a refrigerant circulating between indoor unit and outdoor unit via a refrigerant loop, a four-way valve and piping and controller in communication with a plurality of sensors, said controller in the event of single or multi-sensor failure, is configured to determine a virtual value of at least a failed sensor based on a plurality of first and second predetermined values; determining the heat cool system run status based on the multi-sensor failure matrix in the event of multi-sensor failure; and obtaining, determining a real-time virtual value of at least the failed sensor based on an interlock value matrix for running heat and cool refrigeration cycles without stopping the heat cool system even in the event of single or multi-sensor failure.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to the other elements to help improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference signs are used to depict the same or similar elements, features, and structures.

While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspects of the invention to the embodiment illustrated.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. Embodiments of the present disclosure will now be described with reference to the accompanying drawings. Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to a person skilled in the art. Numerous details are set forth relating to specific components to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

In general, the present invention a method for operating a heat cool system during a sensor failure and system thereof. The method comprises determining, by the controller, in the event of single or multi-sensor failure, a virtual value of at least a failed sensor based on a plurality of first and second predetermined values; determining the heat cool system run status based on the multi-sensor failure matrix in the event of multi-sensor failure; and obtaining, determining a real-time virtual value of at least the failed sensor based on an interlock value matrix for running heat and cool refrigeration cycles without stopping the heat cool system.

According to an aspect, the present invention discloses a method of operating a heat cool system in the event of sensor failure without stopping. The method comprises the steps of storing, by a controller, a plurality of first predetermined values; determining and storing by the controller, a plurality of second predetermined values obtained from a plurality of sensors, after an initial startup of the heat cool system; determining, by the controller, a status of the plurality of sensors in communication with the controller located within the heat cool system; determining, by the controller, a single or multi-sensor failure else determining a plurality of real-time values obtained by the plurality of sensors; determining, by the controller, the heat cool system run status based on a multi-sensor failure matrix triggered on determining the multi-sensor failure; determining, by the controller in the event of single or multi-sensor failure, a virtual value of at least a failed sensor based on the plurality of first and second predetermined values; and comparing, by the controller if the determined virtual value of at least the failed sensor satisfies an interlock value matrix and obtaining, determining a real-time virtual value of at least the failed sensor based on the interlock value matrix for running heat and cool refrigeration cycles without stopping the heat cool system.

According to an embodiment, the method includes the step of determining, by the controller, if an initial bypass delay time has passed after the startup of the heat cool system precedes the step of determining and storing plurality of second predetermined values. The method also includes the step of actuating, by the controller, an error display and simultaneously initiating a start timer and storing counter values on determining single or multi-sensor failure. In the present invention, the plurality of second predetermined values in the event of sensor failure are determined based on a moving average of last thirty seconds data/values obtained from each of the plurality of the sensors.

According to the exemplary embodiment, the method includes the step of determining the heat cool system run status based on the multi-sensor failure matrix includes determining by the controller to run the system: in the event of failure of ambient temperature sensor and coil temperature sensor by determining a virtual ambient temperature value and a virtual coil temperature value; or in the event of failure of ambient temperature sensor and discharge temperature sensor by determining a virtual ambient temperature and a virtual discharge temperature; or in the event of failure of ambient temperature sensor and liquid pressure sensor by determining a virtual ambient temperature value and a virtual liquid pressure; or in the event of failure of coil temperature sensor and ambient temperature sensor by determining a virtual coil temperature value and a virtual ambient temperature value; or in the event of failure of coil temperature sensor and discharge temperature sensor by determining a virtual coil temperature and a virtual discharge temperature value; or in the event of failure of coil temperature sensor and liquid pressure sensor by determining a virtual coil temperature value and a virtual liquid pressure value; or in the event of failure of liquid pressure sensor and ambient temperature sensor by determining a virtual liquid pressure value and a virtual ambient temperature; or in the event of failure of liquid pressure sensor and discharge temperature sensor by determining a virtual liquid pressure and a virtual discharge temperature value; or in the event of failure of liquid pressure sensor and coil temperature sensor by determining a virtual liquid pressure value and a virtual coil temperature value; or in the event of failure of discharge temperature sensor and ambient temperature sensor by determining a virtual discharge temperature value and a virtual ambient temperature value; or in the event of failure of discharge temperature sensor and coil temperature sensor by determining a virtual discharge temperature value and virtual coil temperature value; or in the event of failure of discharge temperature sensor and liquid temperature sensor by determining a virtual discharge temperature value and a virtual liquid temperature value; or in the event of failure of liquid temperature sensor by determining a virtual liquid temperature.

According to the exemplary embodiment, the method includes the step of determining the heat cool system run status based on the multi-sensor failure matrix includes determining by the controller to stop the system in the event of failure of liquid pressure sensor and liquid temperature sensor; or in the event of failure of discharge temperature sensor and the liquid pressure sensor; or in the event of failure of suction pressure sensor or the suction temperature sensor.

According to the exemplary embodiment, the step of obtaining the real-time virtual value in the event of failure of an ambient temperature sensor, or a coil temperature sensor, or a discharge temperature sensor, or a liquid pressure sensor based on the interlock value matrix includes the steps of: determining by the controller: if the determined virtual ambient temperature value is less than the coil temperature value and obtaining real-time virtual ambient temperature value to be equal to the coil temperature value; or if the determined virtual discharge temperature value is less than the liquid temperature value and obtaining real-time virtual discharge temperature value to be equal to the liquid temperature value; or if the determined virtual liquid pressure sensor value is less than a saturated liquid pressure and obtaining real-time liquid pressure sensor value to be equal to the saturated liquid pressure; or determining by the controller: if the determined virtual ambient temperature value is greater than the liquid temperature value and obtaining real-time virtual ambient temperature value to be equal to the liquid temperature value; or if the determined virtual coil temperature value is greater than the suction temperature value and obtaining real-time virtual coil temperature value to be equal to the suction temperature value; or if the determined virtual discharge temperature value is greater than the liquid temperature value +F1 and obtaining real-time virtual discharge temperature value to be equal to the liquid temperature value +F1; or if the determined virtual liquid pressure sensor value is greater than a saturated liquid pressure corresponding to the discharge temperature and obtaining real-time liquid pressure sensor value to be equal to the saturated liquid pressure corresponding to the discharge temperature.

According to the exemplary embodiment, the controller in the event of failure of a coil temperature sensor determines that there is no limit of minimum interlock for the determined virtual value of the coil temperature sensor.

According to the exemplary embodiment, the method includes the step of tripping and stopping compressor by the controller, if the determined counter values are greater than a predefined period or based on the determined heat cool system run status determined based on the multi-sensor failure matrix.

According to the exemplary embodiment, the value of F1 is in the range of 0-200 deg F. and the stored counter values are greater than or equal to 200 hours.

According to another aspect, the present invention disclose a heat cool system comprising an outdoor unit equipped with an inverter-driven compressor; an indoor unit; evaporator and a condenser; an expansion device; a refrigerant circulating between indoor unit and outdoor unit via a refrigerant loop, a four-way valve and piping and controller in communication with a plurality of sensors, said controller in the event of single or multi-sensor failure, is configured to determine a virtual value of at least a failed sensor based on a plurality of first and second predetermined values; determining the heat cool system run status based on the multi-sensor failure matrix in the event of multi-sensor failure; and obtaining, determining a real-time virtual value of at least the failed sensor based on an interlock value matrix for running heat and cool refrigeration cycles without stopping the heat cool system. The plurality of first predetermined values includes constants and the plurality of second predetermined values includes a suction pressure, a suction temperature, an ambient temperature, a coil temperature, a liquid temperature, a liquid pressure, a compressor frequency, and a discharge temperature.

The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. As used in the present disclosure, the forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises,” “comprising,” “including,” “made of” and “having,” are open ended transitional phrases.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention, for example of refrigerant, temperatures, pressures, referred in the description are provided for illustration purpose and understanding only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. The skilled person will be able to devise apply the method to operate various types of HAVAC system, air-to-air inverter heat pump system and not only limited to heat cool system. The skilled person will be able to devise various types of refrigerants, sensors, type of controllers, although not explicitly described herein, embody the principles of the present invention. All the terms and expressions in the description are only for the purpose of understanding and nowhere limit the invention. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein may be made without departing from the scope of the invention. Terms like first, second, predefined, predetermined, plurality and the like are used to differentiate between objects having the same terminology and are in no way intended to represent a chronological order, unless where explicitly stated otherwise. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof. Thus, while HAVAC system, air-to-air inverter heat pump system, refrigerants, sensor, material, quantity, numbers, input values, temperatures, pressures, predetermined values, time intervals, have been disclosed, such components nowhere limit the invention and are provided for understanding of the invention. It will be appreciated that the embodiments may be manufactured with other design parameters and configurations as well and are not limited to those described herein above may be as per operational requirements by making necessary changes and is not limited to those described herein and nowhere limits the scope of the invention and are provided only for reference and for understating purpose of the invention. The structure and design of the system may vary accordingly as well.

discloses a system (), a method () and a flow chart () of a heat cool system () that operates even in the event of single or multiple sensor failures. Accordingly, an aspect of the present invention discloses referring, a heating, ventilation, and air Conditioning (HVAC) system and more specifically to an air-to-air inverter heat pump system () for heating and cooling indoor spaces. The present invention discloses a heat cool system () for heating and cooling indoor spaces. The system () comprises an outdoor unit () equipped with an inverter-driven compressor () to modulate speed and capacity based on the heating or cooling demand. In the system (), heat exchange occurs in a coil-type heat exchanger within indoor () and outdoor units (), with refrigerant circulating between them via piping (). The refrigerant circulates throughout the heat pump system () by means of a refrigerant loop () and piping ().

According to an exemplary embodiment, in the system () of the present invention, the refrigerant leaves an evaporator () and enters the compressor () where the pressure of the refrigerant is increased, changing its condensation point. The compressed refrigerant leaves the compressor () and enters a condenser () where it is condensed from a vapor to a liquid refrigerant by heat exchange. The liquid refrigerant is then returned, by means of an expansion device (), to the evaporator () to continue the cycle through the refrigerant. A four-way valve () present at an outlet of the compressor () controls path of refrigerant and in turn controls whether it is used for a heating application or for a cooling application.

According to the exemplary embodiment, the system () in the heating cycle, the inverter-driven compressor () starts operating drawing in ambient air, and the compressor () compresses the low-pressure refrigerant vapor into high-pressure, high-temperature vapor. This high-pressure vapor refrigerant is then directed to the indoor coil, which acts as the condenser (). Here, the refrigerant releases its heat to the indoor air, condensing into a high-pressure, medium-temperature liquid. Then the refrigerant passes to the electronic expansion Valve (EXV) () which controls the flow of refrigerant, converting the high-pressure liquid refrigerant into low-pressure, low-temperature liquid. This low-pressure liquid refrigerant is then transferred to the outdoor unit's coil, which acts as the evaporator (). In this coil, the refrigerant evaporates into low-pressure vapor and becomes superheated. The superheated vapor is then returned to the suction line and drawn back into the compressor (), restarting the heating cycle.

According to the exemplary embodiment, the system () in the cooling cycle, the inverter-driven compressor () activates, drawing in ambient air and compresses the low-pressure refrigerant vapor into high-pressure vapor. This high-pressure vapor refrigerant is directed to the outdoor unit's coil (), which acts as the condenser. In this coil, the refrigerant releases its heat to the outdoor air, condensing into a high-pressure, medium-temperature liquid. Then the refrigerant is passed into the Electronic Expansion Valve (EXV) which controls the flow of refrigerant, converting the high-pressure liquid refrigerant into low-pressure, low-temperature liquid. This low-pressure liquid refrigerant is then transferred to the indoor coil (), which acts as the evaporator. In the evaporator, the refrigerant evaporates into low-pressure vapor and absorbs heat from the indoor air. The low-pressure vapor is then drawn back into the compressor, where it is compressed back into high-pressure refrigerant vapor, completing the cooling cycle.

According to the exemplary embodiment of the present invention, the system () includes a plurality of sensors for operating during both cooling and heating cycles. The sensors include but not limited to an ambient temperature sensor (), a coil temperature sensor (), a discharge temperature sensor (), a suction temperature sensor (), a liquid temperature sensor (), a liquid pressure sensor (), and a suction pressure sensor ().

According to the exemplary embodiment, referring, a controller () of the heat cool system () is in communication with the plurality of sensors. The controller () may include but not limited to at least one processor, in communication with the plurality of sensors positioned at various components of the system ().

According to the exemplary embodiment of the present invention, the controller () in the cool cycle, is configured to actuate the ambient temperature sensor (), for controlling and limiting the compressor () based on real-time high and low values of ambient temperature and for controlling outdoor unit fan at a low ambient temperature; and in the heat cycle, is configured to actuate the ambient temperature sensor (), for determining defrost and controlling a crankcase heater.

According to the exemplary embodiment, the controller () in the cool cycle, is configured to actuate the coil temperature sensor (), for controlling a condenser cool fan speed and determining a saturated discharge temperature value; and in the heat cycle, is configured to actuate the coil temperature sensor (), for controlling defrost initiation and exit and determining a compressor () motor temperature. The coil temperature sensor () also helps to determine the compressor () motor temperature thus protecting the motor from burnout.

According to the exemplary embodiment, the controller () in the cool and heat cycle, is configured to actuate the discharge temperature sensor (), for protecting the compressor () and determining a discharge superheat value which is used for various control operation and protection from liquid flood back.

According to the exemplary embodiment, the controller () in the cool cycle, is configured to actuate the suction temperature sensor (), for controlling a compressor () frequency; and in the heat cycle, is configured to actuate the suction temperature sensor (), for controlling a compressor () frequency, the suction pressure sensor () for determining a suction superheat and modulate expansion valve (), and for triggering a gas shortage protection control.

According to the exemplary embodiment, the controller () in the cool and heat cycle, is configured to actuate the liquid temperature sensor () for controlling subcooling and determining gas overcharge.

According to the exemplary embodiment, the controller () in the cool cycle, is configured to actuate the liquid pressure sensor (), for triggering a high liquid pressure protection control; and in the heat cycle, is configured to actuate the liquid pressure sensor (), for triggering a high liquid pressure protection control and determining a saturated liquid temperature for compressor () control.

According to the exemplary embodiment, the controller () in the cool cycle, is configured to actuate the suction pressure sensor (), for triggering a low suction pressure protection control and determining the saturated suction temperature for compressor (); and in the heat cycle, is configured to actuate the suction pressure sensor (), for triggering the low suction pressure protection control.

According to another aspect, the present invention in present invention discloses a method () of operating the system () in case of failure of sensors. The method includes the controller () retrieving at least the information from compressor () and evaporator () but not limited to a suction pressure (), a suction temperature (), an ambient temperature (), a coil temperature (), a liquid pressure (), and a liquid temperature (). The controller () further measures compressors RPS (). The controller () is in communication with an invertor drive () that runs the compressor ().

According to the exemplary embodiment, the suction pressure (), Pis the refrigerant temperature measured at an inlet of the compressor (), the suction temperature (), Tis the refrigerant temperature measured at the inlet of the compressor (), the coil temperature (), Tis the refrigerant temperature measured at a u-bend of the fin and tube heat exchanger (), the discharge temperature, Tis the refrigerant temperature measured at the outlet of the compressor (), the liquid temperature (), Tis the refrigerant temperature measured at the inlet of the outdoor expansion device (), the ambient temperature (), Tis the air temperature measured at the inlet of the outdoor unit (), the liquid pressure (), P, is the refrigerant pressure measured at inlet of the expansion device () and the compressor frequency (RPM) is the mechanical frequency at which the compressor () is running by the inverter drive ().

According to the exemplary embodiment, in the method, the controller takes input from sensors that include the suction pressure sensor (), the suction temperature sensor (), the discharge temperature sensor (), the liquid pressure sensor (), the liquid temperature sensor (), the ambient temperature sensor (), and the coil temperature sensor (). The controller () drives the compressor () through the inverter drive (). The feedback of the speed of the compressor (RPS) () is also taken as an input value for the controller (). The controller is configured to run the system () in the event of failure of the sensors and at the same time initiate protection of the system and various components from any failures.

Referringillustrates a flow chart showing a method () of operating the heat cool system () in case of failure of sensors according to an exemplary aspect of the present invention. The method comprises the steps of (): determining initial startup of the heat cool system by the controller (); step (): if the controller () determines that the heat cool system is started, the controller () initiates a protocol to if a predetermined initial bypass delay time is passed else the controller proceeds to step (). In step (), the controller () performs sensor health checks on plurality of the sensors of the heat cool system. Then in step (), the control () determines if a sensor failure has occurred. If the controller () determines that sensor failure has not occurred the controller in step () is configured to determine real-time values obtained by the sensors else, in step (), when the controller determines that the sensor failure has occurred, it initiates a protocol to start a timer and store counter values in a memory. Then the method proceeds to step (), wherein the controller is configured to determine the occurrence of multiple sensor failures. The method in step (), if the controller determines that multiple sensor failures have not occurred, then the controller initiates a protocol to determine virtual values of failed sensors.

According to an exemplary embodiment, according to step (), the controller () in the event of failure of the ambient temperature sensor (), initiates a protocol to obtain predefined first values from a memory of a processor and values relating to the suction pressure () obtained from suction pressure sensor () which is a second predetermined value. The controller (), on obtaining the required values initiates calculation of a virtual ambient temperature value in the following manner:

Thus, even in the event of failure of the ambient temperature sensor (), the system () generates the virtual ambient temperature value and therefore does not stop system () operation, thereby providing protection to the system () and the components of the system ().

According to the exemplary embodiment, the controller () in step (), in the event of failure of the coil temperature sensor (), initiates a protocol to obtain predefined values from the memory of the processor and values relating to the suction pressure () obtained from suction pressure sensor (). The controller () further obtains the ambient temperature value () from the ambient temperature sensor () or the calculated virtual ambient temperature value. The controller (), on obtaining the required values initiates calculation of a virtual coil temperature value in the following manner:

Thus, according to the method of the present invention, even in the event of failure of the coil temperature sensor (), the system () generates the virtual coil temperature value and therefore does not stop the system () operation, thereby providing protection to the system () and the components of the system ().

According to the exemplary embodiment, the controller () in the step (), in the event of failure of the discharge temperature sensor (), initiates a protocol to obtain predefined values from the memory of the processor and values relating to the suction temperature () obtained from suction temperature sensor (). The controller (), on obtaining the required values initiates calculation of a virtual discharge temperature value in the following manner:

Thus, according to the method of the present invention, even in the event of failure of the discharge temperature sensor (), the system () generates the virtual discharge temperature value and therefore does not stop the system () operation, thereby providing protection to the system () and the components of the system ().

According to the exemplary embodiment, the controller () in step (), in the event of failure of the liquid pressure sensor (), initiates a protocol to obtain predefined values from the memory of the processor and values relating to the feedback of the speed of the compressor (RPS) (). The controller (), on obtaining the required values initiates calculation of a virtual liquid pressure value in the following manner: