METHOD FOR OPERATING A HEAT COOL SYSTEM DURING A SENSOR FAILURE AND A SYSTEM THEREOF

Abstract

The present invention discloses a method for operating a heat cool system during a sensor failure and system thereof. The method comprises determining, by 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 a 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.

Claims

1. A method of operating a heat cool system, the method 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.

2. The method according to claim 1, wherein 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.

3. The method according to claim 1, wherein the method 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.

4. The method according to claim 1, wherein 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.

5. The method according to claim 1, wherein 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.

6. The method according to claim 1, wherein 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.

7. The method according to claim 1, wherein 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 or a combination thereof 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.

8. The method according to claim 1, wherein 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.

9. The method according to claim 1, wherein 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.

10. The method according to claim 7, wherein 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.

11. A heat cool system comprising an outdoor unit equipped with an inverter-driven compressor; an indoor unit; an evaporator and a condenser; an expansion device; a refrigerant circulating between indoor unit and outdoor unit via a refrigerant loop, a four-way valve, piping and a 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 a second predetermined values; determine the heat cool system run status based on a multi-sensor failure matrix in the event of multi-sensor failure; and obtain, determine 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.

12. The heat cool system according to claim 11, wherein 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.

13. The heat cool system according to claim 11, wherein the plurality of sensors includes 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.

Description

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[0006] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0007] FIG. 1 illustrates a refrigerant circuit of a heat cool system, according to an exemplary aspect of the present invention;

[0008] FIG. 2 illustrates a controller of the system with a plurality of sensors, according to an exemplary embodiment of the present invention; and

[0009] FIG. 3 illustrates a flow chart showing a method of operating of the heat cool system during a sensor failure, according to another exemplary aspect of the present invention.

[0010] 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.

DETAILED DESCRIPTION

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] FIGS. 1-3 discloses a system (100), a method (200) and a flow chart (300) of a heat cool system (100) that operates even in the event of single or multiple sensor failures. Accordingly, an aspect of the present invention discloses referring FIG. 1, a heating, ventilation, and air Conditioning (HVAC) system and more specifically to an air-to-air inverter heat pump system (100) for heating and cooling indoor spaces. The present invention discloses a heat cool system (100) for heating and cooling indoor spaces. The system (100) comprises an outdoor unit (130) equipped with an inverter-driven compressor (115) to modulate speed and capacity based on the heating or cooling demand. In the system (100), heat exchange occurs in a coil-type heat exchanger within indoor (120) and outdoor units (130), with refrigerant circulating between them via piping (110). The refrigerant circulates throughout the heat pump system (100) by means of a refrigerant loop (125) and piping (110).

[0026] According to an exemplary embodiment, in the system (100) of the present invention, the refrigerant leaves an evaporator (130) and enters the compressor (115) where the pressure of the refrigerant is increased, changing its condensation point. The compressed refrigerant leaves the compressor (115) and enters a condenser (120) 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 (135), to the evaporator (130) to continue the cycle through the refrigerant. A four-way valve (140) present at an outlet of the compressor (115) controls path of refrigerant and in turn controls whether it is used for a heating application or for a cooling application.

[0027] According to the exemplary embodiment, the system (100) in the heating cycle, the inverter-driven compressor (115) starts operating drawing in ambient air, and the compressor (115) 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 (120). 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) (135) 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 (130). 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 (115), restarting the heating cycle.

[0028] According to the exemplary embodiment, the system (100) in the cooling cycle, the inverter-driven compressor (115) 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 (130), 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 (120), 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.

[0029] According to the exemplary embodiment of the present invention, the system (100) includes a plurality of sensors for operating during both cooling and heating cycles. The sensors include but not limited to an ambient temperature sensor (150), a coil temperature sensor (155), a discharge temperature sensor (160), a suction temperature sensor (165), a liquid temperature sensor (170), a liquid pressure sensor (175), and a suction pressure sensor (180).

[0030] According to the exemplary embodiment, referring FIG. 2, a controller (200) of the heat cool system (100) is in communication with the plurality of sensors. The controller (200) may include but not limited to at least one processor, in communication with the plurality of sensors positioned at various components of the system (100).

[0031] According to the exemplary embodiment of the present invention, the controller (200) in the cool cycle, is configured to actuate the ambient temperature sensor (150), for controlling and limiting the compressor (115) 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 (150), for determining defrost and controlling a crankcase heater.

[0032] According to the exemplary embodiment, the controller (200) in the cool cycle, is configured to actuate the coil temperature sensor (155), 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 (155), for controlling defrost initiation and exit and determining a compressor (115) motor temperature. The coil temperature sensor (155) also helps to determine the compressor (115) motor temperature thus protecting the motor from burnout.

[0033] According to the exemplary embodiment, the controller (200) in the cool and heat cycle, is configured to actuate the discharge temperature sensor (160), for protecting the compressor (115) and determining a discharge superheat value which is used for various control operation and protection from liquid flood back.

[0034] According to the exemplary embodiment, the controller (200) in the cool cycle, is configured to actuate the suction temperature sensor (165), for controlling a compressor (115) frequency; and in the heat cycle, is configured to actuate the suction temperature sensor (165), for controlling a compressor (115) frequency, the suction pressure sensor (180) for determining a suction superheat and modulate expansion valve (135), and for triggering a gas shortage protection control.

[0035] According to the exemplary embodiment, the controller (200) in the cool and heat cycle, is configured to actuate the liquid temperature sensor (170) for controlling subcooling and determining gas overcharge.

[0036] According to the exemplary embodiment, the controller (200) in the cool cycle, is configured to actuate the liquid pressure sensor (175), for triggering a high liquid pressure protection control; and in the heat cycle, is configured to actuate the liquid pressure sensor (175), for triggering a high liquid pressure protection control and determining a saturated liquid temperature for compressor (115) control.

[0037] According to the exemplary embodiment, the controller (200) in the cool cycle, is configured to actuate the suction pressure sensor (180), for triggering a low suction pressure protection control and determining the saturated suction temperature for compressor (115); and in the heat cycle, is configured to actuate the suction pressure sensor (180), for triggering the low suction pressure protection control.

[0038] According to another aspect, the present invention in present invention discloses a method (300) of operating the system (100) in case of failure of sensors. The method includes the controller (200) retrieving at least the information from compressor (115) and evaporator (130) but not limited to a suction pressure (210), a suction temperature (220), an ambient temperature (230), a coil temperature (240), a liquid pressure (250), and a liquid temperature (260). The controller (200) further measures compressors RPS (270). The controller (200) is in communication with an invertor drive (205) that runs the compressor (115).

[0039] According to the exemplary embodiment, the suction pressure (210), P.sub.suct is the refrigerant temperature measured at an inlet of the compressor (115), the suction temperature (220), T.sub.suct is the refrigerant temperature measured at the inlet of the compressor (115), the coil temperature (240), T.sub.coil is the refrigerant temperature measured at a u-bend of the fin and tube heat exchanger (130), the discharge temperature, T.sub.dis is the refrigerant temperature measured at the outlet of the compressor (115), the liquid temperature (260), T.sub.liq is the refrigerant temperature measured at the inlet of the outdoor expansion device (135), the ambient temperature (230), T.sub.amb is the air temperature measured at the inlet of the outdoor unit (130), the liquid pressure (250), P.sub.liqd, is the refrigerant pressure measured at inlet of the expansion device (135) and the compressor frequency (RPM) is the mechanical frequency at which the compressor (115) is running by the inverter drive (205).

[0040] According to the exemplary embodiment, in the method, the controller takes input from sensors that include the suction pressure sensor (180), the suction temperature sensor (165), the discharge temperature sensor (160), the liquid pressure sensor (175), the liquid temperature sensor (170), the ambient temperature sensor (150), and the coil temperature sensor (155). The controller (200) drives the compressor (115) through the inverter drive (205). The feedback of the speed of the compressor (RPS) (270) is also taken as an input value for the controller (200). The controller is configured to run the system (100) in the event of failure of the sensors and at the same time initiate protection of the system and various components from any failures.

[0041] Referring FIG. 3 illustrates a flow chart showing a method (300) of operating the heat cool system (100) in case of failure of sensors according to an exemplary aspect of the present invention. The method comprises the steps of (305): determining initial startup of the heat cool system by the controller (200); step (310): if the controller (200) determines that the heat cool system is started, the controller (200) initiates a protocol to if a predetermined initial bypass delay time is passed else the controller proceeds to step (315). In step (315), the controller (200) performs sensor health checks on plurality of the sensors of the heat cool system. Then in step (320), the control (200) determines if a sensor failure has occurred. If the controller (200) determines that sensor failure has not occurred the controller in step (324) is configured to determine real-time values obtained by the sensors else, in step (325), 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 (330), wherein the controller is configured to determine the occurrence of multiple sensor failures. The method in step (335), if the controller determines that multiple sensor failures have not occurred, then the controller initiates a protocol to determine virtual values of failed sensors.

[0042] According to an exemplary embodiment, according to step (335), the controller (200) in the event of failure of the ambient temperature sensor (150), initiates a protocol to obtain predefined first values from a memory of a processor and values relating to the suction pressure (210) obtained from suction pressure sensor (180) which is a second predetermined value. The controller (200), on obtaining the required values initiates calculation of a virtual ambient temperature value in the following manner:

[00001]$\mathrm{Virtual}\mathrm{ambient}\mathrm{temperature}\mathrm{value}=(\left(\mathrm{Amb}2-\mathrm{Amb}1\right)/A5\left(\mathrm{RPM}-A6\right)+\mathrm{Amb}1$$\mathrm{where},$$\mathrm{Amb}1=A1P_{\mathrm{suct}}-A2;$$\mathrm{Amb}2=A3P_{\mathrm{suct}}-A4;$ [0043] A1, A2, A3, A4, A5 and A6 are constants; [0044] The values of the constants vary within the following range:

TABLE-US-00001 A1 0.1-1.5 A2 0-100 A3 0.1-1.5 A4 0-100 A5 1000-10000 A6 1000-10000

[0045] Thus, even in the event of failure of the ambient temperature sensor (150), the system (100) generates the virtual ambient temperature value and therefore does not stop system (100) operation, thereby providing protection to the system (100) and the components of the system (100).

[0046] According to the exemplary embodiment, the controller (200) in step (335), in the event of failure of the coil temperature sensor (155), initiates a protocol to obtain predefined values from the memory of the processor and values relating to the suction pressure (210) obtained from suction pressure sensor (180). The controller (200) further obtains the ambient temperature value (230) from the ambient temperature sensor (150) or the calculated virtual ambient temperature value. The controller (200), on obtaining the required values initiates calculation of a virtual coil temperature value in the following manner:

[00002]$\mathrm{Virtual}\mathrm{coil}\mathrm{temperature}\mathrm{value}=\left(\mathrm{Coil}2-\mathrm{Coil}1\right)/C5\left(Tamb-C6\right)+\mathrm{Coil}1-\left[\max \mathrm{value}\mathrm{of}\left(C7-P_{\mathrm{suct}},0\right)\right]C8$$\mathrm{where},$$\mathrm{Coil}1=C1\mathrm{RPM}+C2;$$\mathrm{Coil}2=C3\mathrm{RPM}+C4;$ [0047] C1, C2, C3, C4, C5, C6, C7 and C8 are constants; [0048] The values of the constants vary within the following range:

TABLE-US-00002 C1 0.0001-0.0010 C2 100-100 C3 0.0001-0.0010 C4 100-100 C5 100-100 C6 100-100 C7- 0-150 C8 0.0-5.0

[0049] Thus, according to the method of the present invention, even in the event of failure of the coil temperature sensor (155), the system (100) generates the virtual coil temperature value and therefore does not stop the system (100) operation, thereby providing protection to the system (100) and the components of the system (100).

[0050] According to the exemplary embodiment, the controller (200) in the step (335), in the event of failure of the discharge temperature sensor (160), initiates a protocol to obtain predefined values from the memory of the processor and values relating to the suction temperature (220) obtained from suction temperature sensor (165). The controller (200), on obtaining the required values initiates calculation of a virtual discharge temperature value in the following manner:

[00003]$\mathrm{Virtual}\mathrm{discharge}\mathrm{temperature}\mathrm{value}=\left(\mathrm{Dis}2-\mathrm{Dis}1\right)/D5\left(Tsuct-D6\right)+\mathrm{Dis}1+\left[\mathrm{Max}\mathrm{value}\mathrm{of}\left(65-D7,0\right)\right]D8$$\mathrm{where},$$\mathrm{Dis}1=D1P_{\mathrm{liq}}+D2;$$\mathrm{Dis}2=D3P_{\mathrm{liq}}+D4;$ [0051] D1, D2, D3, D4, D5, D6, D7 and D8 are constants; [0052] The values of the constants vary within the following range:

TABLE-US-00003 D1 0.1-1.0 D2 100-100 D3 0.1-1.0 D4 100-100 D5 100-100 D6 100-100 D7 0-150 D8 0.0-5.0

[0053] Thus, according to the method of the present invention, even in the event of failure of the discharge temperature sensor (160), the system (100) generates the virtual discharge temperature value and therefore does not stop the system (100) operation, thereby providing protection to the system (100) and the components of the system (100).

[0054] According to the exemplary embodiment, the controller (200) in step (335), in the event of failure of the liquid pressure sensor (175), 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) (270). The controller (200), on obtaining the required values initiates calculation of a virtual liquid pressure value in the following manner:

[00004]$\mathrm{Virtual}\mathrm{liquid}\mathrm{pressure}\mathrm{value}=\left(\mathrm{Liq}1-\mathrm{Liq}2\right)/L5\left(RPM-L6\right)+\mathrm{Liq}2$$\mathrm{where},$$\mathrm{Liq}1=L1T_{liq}+L2;$$\mathrm{Liq}2=L3T_{liq}+L4;$ [0055] L1, L2, L3, L4, L5 and L6 are constants; [0056] The values of the constants vary within the following range:

TABLE-US-00004 L1 0.1-10 L2 100-100 L3 0.1-10 L4 100-100 L5 100-10000 L6 100-10000

[0057] Thus, according to the method of the present invention, even in the event of failure of the liquid pressure sensor (175), the system (100) generates the virtual liquid pressure value and therefore does not stop the system (100) operation, thereby providing protection to the system (100) and the components of the system (100).

[0058] According to the exemplary embodiment, in step (310), as the controller (200) during startup of compressor (115), actuates an initial bypass delay after which the control (200) initiation calculation of the virtual sensor values of the failed sensors. The initial bypass delay by the controller (200) prevents miss-detection of values arising from transient conditions during startup of compressor (115). Thus, with the virtual sensor values, the system (200) ensures start of the compressor (115) even if the sensors failure occurred during initial startup.

[0059] According to the exemplary embodiment, according to the method of the present invention, the controller (200) follows a moving average method to determine the virtual sensor values. The controller (200) obtains the last/recent or latest thirty seconds data/values of the sensors before failure and then calculates the predetermined values for obtaining the virtual values based on moving average of the obtained last thirty seconds data/values of the sensors.

[0060] According to the exemplary embodiment, the controller after step (330), determines that the multiple sensors failure has occurred, the controller proceeds to check the system run status based on a multiple sensor failure matrix.

[0061] According to the exemplary embodiment, according to the method of the present invention, the controller (200) based on the multiple sensor failure matrix for example in the event of failure of ambient temperature sensor (150) and coil temperature sensor (155) is configured to calculate the virtual ambient temperature and virtual coil temperature without stopping the system (100) and protect the system and components failure. The controller (200) in the event of failure of ambient temperature sensor (150) and discharge temperature sensor (160) is configured to calculate the virtual ambient temperature and virtual discharge temperature without stopping the system (100) and protect the system and components failure. The controller (200) in the event of failure of ambient temperature sensor (150) and liquid pressure sensor (175) is configured to calculate the virtual ambient temperature and virtual liquid pressure without stopping the system (100) and protect the system and components failure.

[0062] According to the exemplary embodiment, according to the method of the present invention, the controller (200) based on the multiple sensor failure matrix in the event of failure of coil temperature sensor (155) and ambient temperature sensor (150) is configured to calculate the virtual coil temperature and virtual ambient temperature without stopping the system (100) and protect the system and components failure. The controller (200) based on the multiple sensor failure matrix in the event of failure of coil temperature sensor (155) and discharge temperature sensor (160) is configured to calculate the virtual coil temperature and virtual discharge temperature without stopping the system (100) and protect the system and components failure. The controller (200) based on the multiple sensor failure matrix in the event of failure of coil temperature sensor (155) and liquid pressure sensor (175) is configured to calculate the virtual coil temperature and virtual liquid pressure without stopping the system (100) and protect the system and components failure.

[0063] According to the exemplary embodiment, according to the method of the present invention, the controller (200) based on the multiple sensor failure matrix in the event of failure of liquid pressure sensor (175) and ambient temperature sensor (150) is configured to calculate the virtual liquid pressure and virtual ambient temperature without stopping the system (100) and protect the system and components failure. The controller (200) based on the multiple sensor failure matrix in the event of failure of liquid pressure sensor (175) and discharge temperature sensor (160) is configured to calculate the virtual liquid pressure and virtual discharge temperature without stopping the system (100) and protect the system and components failure. The controller (200) based on the multiple sensor failure matrix in the event of failure of liquid pressure sensor (175) and coil temperature sensor (155) is configured to calculate the virtual liquid pressure and virtual coil temperature without stopping the system (100) and protect the system and components failure. The controller (200) based on the multiple sensor failure matrix in the event of failure of liquid pressure sensor (175) and liquid temperature sensor (170) is configured stop the system (100) and protect the system and components failure.

[0064] According to the exemplary embodiment, according to the method of the present invention, the controller (200) based on the multiple sensor failure matrix in the event of failure of discharge temperature sensor (160) and ambient temperature sensor (150) is configured to calculate the virtual discharge temperature and virtual ambient temperature without stopping the system (100) and protect the system and components failure. The controller (200) based on the multiple sensor failure matrix in the event of failure of discharge temperature sensor (160) and the liquid pressure sensor (175) is configured stop the system (100) and protect the system and components failure. The controller (200) based on the multiple sensor failure matrix in the event of failure of discharge temperature sensor (160) and coil temperature sensor (155) is configured to calculate the virtual discharge temperature and virtual coil temperature without stopping the system (100) and protect the system and components failure. The controller (200) based on the multiple sensor failure matrix in the event of failure of discharge temperature sensor (160) and liquid temperature sensor (170) is configured to calculate the virtual discharge temperature and virtual liquid temperature without stopping the system (100) and protect the system and components failure.

[0065] According to the exemplary embodiment, according to the method of the present invention, the controller (200) based on the multiple sensor failure matrix in the event of failure of suction pressure sensor (180) or the suction temperature sensor (165) is configured stop the system (100) and protect the system and components failure.

[0066] According to the exemplary embodiment, according to the method of the present invention, the controller (200) based on the multiple sensor failure matrix in the event of failure of liquid temperature sensor (170) is configured without stopping the system (100) as this sensor is not critical to any protection logic. It is primarily used by field personnel during commissioning.

[0067] The following table 1 summarizes the above description of the operation of the controller (200) on failure of sensors based on multi-sensor failure matrix:

TABLE-US-00005 Sensor Failure 1 Sensor Failure 2 Effect on system Ambient Sensor Coil Temp System Continue to run Discharge Temp System Continue to run Liquid Pressure System Continue to run Coil Temp Sensor Ambient Temp System Continue to run Discharge Temp System Continue to run Liquid Pressure System Continue to run Liquid Pres Sensor Ambient Temp System Continue to run Discharge Temp System Continue to run Coil Temperature System Continue to run Liquid Temp System stop Liquid Temp Sensor NA System Continue to run Discharge Temp Ambient Temp System Continue to run Liquid Pressure System stop Coil Temp System Continue to run Liquid Temp System Continue to run Suction Pressure NA System stop Suction Temp NA System stop

[0068] According to the exemplary embodiment, the controller in step (340) on determination of system run status based on the multiple sensor failure matrix in step (345) determines if the system is allowed to run. On determining that the system is allowed to run, the controller determines the virtual values of the failed multiple sensors as in step (335) else, the controller trips the system and stops the compressor, thereby protecting the components of the system.

[0069] According to the exemplary embodiment, the method includes the step of (355), wherein the controller (200) further to prevent incorrect calculation of the virtual values in the event of failed sensor during transient conditions below interlocks maximum and minimum values to control the range of values of the sensors dynamically.

[0070] According to the exemplary embodiment, according to the method of the present invention, the controller (200) in the event of failure of the ambient temperature sensor (150), initiates a protocol to interlock the calculated virtual value of the ambient temperature sensor based on interlock matrix. If the calculated virtual value of the ambient temperature sensor is lower than the value of the coil temperature (240), the controller initiates a protocol to determine that the calculated virtual value of the ambient temperature sensor to be equal to the value of the coil temperature (240) and if the calculated virtual value of the ambient temperature sensor is greater than the value of the liquid temperature (260), the controller initiates a protocol to determine that the calculated virtual value of the ambient temperature sensor to be equal to the value of the liquid temperature (260).

[0071] According to the exemplary embodiment, according to the method of the present invention, the controller (200) in the event of failure of the coil temperature sensor (155), initiates a protocol to interlock the calculated virtual value of the coil temperature sensor (155) based on interlock matrix. If the calculated virtual value of the coil temperature sensor (155) is greater than the value of the suction temperature, the controller initiates a protocol to determine that the calculated virtual value of the ambient temperature sensor to be equal to the value of the suction temperature. The controller (200) in the event of failure of the coil temperature sensor (155), there is no limit of minimum interlock for the calculated virtual value of the coil temperature sensor (155).

[0072] According to the exemplary embodiment, according to the method of the present invention, the controller (200) in the event of failure of the discharge temperature sensor (160), initiates a protocol to interlock the calculated virtual value of the discharge temperature sensor (160) based on interlock matrix. If the calculated virtual value of the discharge temperature sensor (160) is lower than the value of the liquid temperature (260), the controller initiates a protocol to determine that the calculated virtual value of the discharge temperature sensor (160) to be equal to the value of the liquid temperature (260) and if the calculated virtual value of the discharge temperature sensor (160) is greater than the value of the liquid temperature (260)+F1, where F1 is between 0-200 deg F., the controller initiates a protocol to determine that the calculated virtual value of the ambient temperature sensor to be equal to the value of the liquid temperature (260)+F1.

[0073] According to the exemplary embodiment, according to the method of the present invention, The controller (200) in the event of failure of the liquid pressure sensor (175) initiates a protocol to interlock the calculated virtual value of the liquid pressure sensor (175) based on interlock matrix. If the calculated virtual value of the liquid pressure sensor (175) is lower than the value of a saturated liquid pressure, the controller initiates a protocol to determine that the calculated virtual value of the liquid pressure sensor (175) to be equal to the value of the saturated liquid pressure and if the calculated virtual value of the liquid pressure sensor (175) is greater than the value of the saturated pressure corresponding to the discharge temperature, the controller initiates a protocol to determine that the calculated virtual value of the liquid pressure sensor (175) to be equal to the value of the saturated pressure corresponding to the discharge temperature.

[0074] The following table 2 summarizes the above description of the interlock matrix:

TABLE-US-00006 Failed Sensor Minimum Value Maximum Value Ambient Sensor Coil Temperature Liquid Temperature Coil Sensor No Limit Suction Temperature Discharge Temperature Liquid Temperature Liquid Temperature + F1 Liquid Pressure Saturated Liquid Saturated Pressure Pressure corresponding to Discharge Temperature

[0075] According to the exemplary embodiment, the method includes the step (360), wherein the controller (200) determines if the stored counter values are greater than or equal to 200 hours. If the controller determines that the stored counter values are greater than or equal to 200 hours, then in step (365) the controller is configured to reset the counter and trip the system and stop the compressor to protect the components of the system else, the method in step (370), the controller utilizes the determined virtual values of failed sensors to run the system. The controller on detection of failure of sensor is configured to display an error code continuously. The counter provided in the system is triggered to measure total time the failed sensor is open. The counter further only is increased as and when the compressor is running. Once the counter reaches a maximum threshold limit of 200 hours, the system (100) stops till the failed sensor is corrected and actual value of sensor is available.

[0076] According to the exemplary embodiment, with the teachings of the present invention, the controller (200) aids in providing enhanced reliability. The controller (200) by using predictive temperature values, maintains the system (100) operation even if a temperature sensor fails, ensuring continuous heating or cooling without interruptions. The controller (200) of the present invention aids in providing improved system uptime. The controller (200) by using predictive temperature values, minimize downtime associated with sensor failures, leading to improved system reliability and availability. With the teachings of the present invention, as there is reduced reliance on sensor replacements and maintenance, it results in cost savings over time, as fewer service calls and parts replacements are required. In the present invention, the use of predictive values allows the system (100) to adapt and maintain optimal performance levels, ensuring efficient heating and cooling operations under varying conditions. In the present invention, a continuous operation without sensor-related shutdowns ensures consistent indoor comfort levels for users, enhancing overall satisfaction with the system (100). In the present invention, predictive temperature values help prevent system shutdowns due to sensor failures, reducing potential safety risks associated with temperature fluctuations in indoor environments. In the present invention, the system's ability to adapt and adjust based on predictive temperature values demonstrates advanced control capabilities, showcasing innovation in HVAC technology. In the present invention, maintaining consistent operation with predictive temperature values can lead to improved energy efficiency by avoiding unnecessary system shutdowns and restarts.

[0077] The present invention has been described in the context of a control logic for operating a heat cool system for example a HVAC system in the event of failure of sensors. However, the control logic of the present invention can be used in any type of refrigeration system in the event of failure of sensors. To use the control logic in other types of refrigeration systems, some changes may have to be made to the membership functions and the sensor information that is used by the control logic to account for the particular configuration of the system to which the control logic is being applied.

[0078] There have been described and illustrated herein several embodiments of an exemplary implementation of the heat cool system (100) and method (300) for operating the system in the event of failure of sensors. It will also be apparent to a skilled person that the embodiments described above are specific examples of a single broader invention, which may have greater scope than any of the singular descriptions taught. There may be many alterations made in the description without departing from the scope of the invention. The present invention is simple in construction and design, integrated, cost effective and easy to manufacture and assemble. The manufacturing and the operating process of the chiller with desired components, temperatures, values, pressures, type of refrigerant, capacity of components, type of components, and materials nowhere limit the invention and are provided for an understanding of the invention and may be employed depending upon the operational requirements by making necessary changes that are within the scope. Further, the figures are only for reference and understanding the purpose of the invention and do not have a limitation effect in the present application. The present invention has been described in the context method and heat cool system, however the method and systems may be adapted to different refrigerant systems. The present invention has been described in the context of a control fuzzy logic for heat cool system that operates in the event of failure of sensors. However, the fuzzy logic of the present invention can be used in any type of refrigeration system. To use the control logic in other types of refrigeration systems, some changes may have to be made to the membership functions and the sensor information that is used by the control logic to account for the particular configuration of the system to which the control logic is being applied.

[0079] While particular embodiments of the invention have been described, it is not intended that the invention be limited to the configuration disclosed thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise not restrictive to the terminology described herein above. Any discussion of embodiments included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.