Patent ID: 12209782

MODES FOR CARRYING OUT THE INVENTION

A transporting refrigeration apparatus, which is an example of a refrigeration apparatus (hereafter, simply referred to as “refrigeration apparatus1”), will be described below with reference to the drawings. The refrigeration apparatus1is configured to refrigerate the inside of storage, for example, a shipping container or a road transportation trailer container. The inside of a casing of the refrigeration apparatus1is divided into an interior accommodation space that circulates the air in the storage and an exterior accommodation space that circulates the air outside the storage.

As shown inFIG.1, the refrigeration apparatus1includes a refrigerant circuit20in which, for example, a compressor11, a condenser12, and an evaporator13are connected by a refrigerant pipe. The refrigerant circuit20includes a main circuit21, a hot gas bypass circuit22, and a liquid refrigerant bypass circuit31.

In the main circuit21, the compressor11that is motor-driven, the condenser12, a first expansion valve14A, and the evaporator13are sequentially connected in series by the refrigerant pipe.

As shown inFIG.1, the exterior accommodation space accommodates the compressor11, the condenser12, the first expansion valve14A, and an exterior fan15that circulates the air outside the storage to the condenser12. The interior accommodation space accommodates the evaporator13and an interior fan16that circulates the air in the storage to the evaporator13.

The compressor11may be, for example, a rotary compressor or a scroll compressor. The compressor11is configured so that the operating capacity is variable when an inverter controls the operating frequency to control the rotational speed.

The condenser12and the evaporator13may be a fin-and-tube heat exchanger. The condenser12exchanges heat between the air outside the storage supplied by the exterior fan15and the refrigerant circulating in the condenser12. The evaporator13exchanges heat between the air in the storage supplied by the interior fan16and the refrigerant circulating in the evaporator13. An example of the exterior fan15and the interior fan16is a propeller fan. A drain pan28is disposed below the evaporator13. The drain pan28collects, for example, frost and ice blocks falling from the evaporator13and water condensed from the air.

The first expansion valve14A may be, for example, an electric expansion valve having an opening degree that is variable using a pulse motor.

The compressor11and the condenser12are connected by a high pressure gas pipe23that includes a first opening-closing valve17A and a check valve18sequentially arranged in a direction in which the refrigerant flows. The first opening-closing valve17A may be, for example, an electric expansion valve having an opening degree that is variable using a pulse motor. The check valve18allows the refrigerant to flow in directions of arrows shown inFIG.1.

The condenser12and the first expansion valve14A are connected by a high pressure liquid pipe24that includes a receiver29, a second opening-closing valve17B, a dryer30, and a supercooling heat exchanger27sequentially arranged in the direction in which the refrigerant flows. The second opening-closing valve17B may be, for example, an electromagnetic valve capable of opening and closing.

The supercooling heat exchanger27includes a primary passage27aand a secondary passage27bconfigured to exchange heat with each other. The primary passage27ais disposed in the main circuit21between the dryer30and the first expansion valve14A. The secondary passage27bis disposed in the liquid refrigerant bypass circuit31. The liquid refrigerant bypass circuit31is a bypass circuit that connects the high pressure liquid pipe24and an intermediate-pressure portion (not shown) of a compression mechanism of the compressor11. A third opening-closing valve17C and a second expansion valve14B are sequentially connected, in the direction in which the high pressure liquid refrigerant flows, to the liquid refrigerant bypass circuit31between the high pressure liquid pipe24and the secondary passage27b. In this configuration, when the liquid refrigerant flows into the liquid refrigerant bypass circuit31from the high pressure liquid pipe24, the second expansion valve14B expands the liquid refrigerant to an intermediate pressure, so that the liquid refrigerant has a lower temperature than the liquid refrigerant flowing through the high pressure liquid pipe24and flows to the secondary passage27b. Thus, the high pressure liquid refrigerant flowing through the primary passage27ais supercooled by the refrigerant flowing through the secondary passage27b. The third opening-closing valve17C may be, for example, an electromagnetic valve capable of opening and closing. The second expansion valve14B may be, for example, an electric expansion valve having an opening degree that is variable using a pulse motor.

The hot gas bypass circuit22connects the high pressure gas pipe23and the inlet side of the evaporator13and sends the high-pressure high-temperature gas refrigerant discharged from the compressor11to the inlet side of the evaporator13. The hot gas bypass circuit22includes a main passage32, and a first branch passage33and a second branch passage34divided from the main passage32. The first branch passage33and the second branch passage34are configured to be a parallel circuit in which one end of each of the first branch passage33and the second branch passage34is connected to the main passage32and the other end is connected to the inlet side of the evaporator13, that is, a low pressure connection pipe25that extends between the first expansion valve14A and the evaporator13. The main passage32includes a fourth opening-closing valve17D. The fourth opening-closing valve17D may be, for example, an electromagnetic valve capable of opening and closing. The first branch passage33includes only a pipe. The second branch passage34includes a drain pan heater35. The drain pan heater35is disposed at the bottom of the drain pan28to heat the drain pan28with the refrigerant having a high temperature.

The refrigeration apparatus1includes various sensors. In an example, as shown inFIGS.1and2, the refrigeration apparatus1includes a discharge temperature sensor41, a discharge pressure sensor42, an intake temperature sensor43, an intake pressure sensor44, a current sensor45, a rotation sensor46, a condensation temperature sensor47, and an evaporation temperature sensor48. The sensors41to48may be, for example, known sensors.

The discharge temperature sensor41and the discharge pressure sensor42are arranged, for example, on the high pressure gas pipe23in the vicinity of a discharge port of the compressor11. The discharge temperature sensor41outputs a signal corresponding to the temperature of a discharge gas refrigerant discharged from the compressor11. The discharge pressure sensor42outputs a signal corresponding to the pressure of the discharge gas refrigerant discharged from the compressor11. The intake temperature sensor43and the intake pressure sensor44are arranged, for example, on an intake pipe of the compressor11, that is, a low pressure gas pipe26in the vicinity of the intake port of the compressor11. The intake temperature sensor43outputs a signal corresponding to the temperature of an intake gas refrigerant drawn into the compressor11. The intake pressure sensor44outputs a signal corresponding to the pressure of the intake gas refrigerant drawn into the compressor11. The current sensor45is arranged, for example, on an inverter circuit (inverter) that drives the motor of the compressor11. The current sensor45outputs a signal corresponding to the amount of current flowing to the inverter circuit (inverter). The rotation sensor46is arranged, for example, on the motor of the compressor11. The rotation sensor46outputs a signal corresponding to the rotational speed of the motor.

The condensation temperature sensor47is arranged, for example, on the condenser12and outputs a signal corresponding to the condensation temperature of the refrigerant flowing through the condenser12. In the present embodiment, the condensation temperature sensor47is attached to, for example, an intermediate portion of the condenser12. In this case, the condensation temperature sensor47obtains the temperature of the refrigerant in the intermediate portion of the condenser12as the condensation temperature and outputs a signal corresponding to the condensation temperature. The attachment position of the condensation temperature sensor47to the condenser12may be changed in any manner.

The evaporation temperature sensor48is arranged, for example, on the evaporator13and outputs a signal corresponding to the evaporation temperature of the refrigerant flowing through the evaporator13. In the present embodiment, the evaporation temperature sensor48is attached to, for example, an intermediate portion of the evaporator13. In this case, the evaporation temperature sensor48obtains the temperature of the refrigerant in the intermediate portion of the evaporator13as the evaporation temperature and outputs a signal corresponding to the evaporation temperature. The attachment position of the evaporation temperature sensor48to the evaporator13may be changed in any manner.

As shown inFIG.2, the refrigeration apparatus1includes a notification unit52and a control device50that controls operation of the refrigeration apparatus1. The control device50is electrically connected to each of the discharge temperature sensor41, the discharge pressure sensor42, the intake temperature sensor43, the intake pressure sensor44, the current sensor45, the rotation sensor46, the condensation temperature sensor47, and the evaporation temperature sensor48. The control device50is also electrically connected to the compressor11, the first expansion valve14A, the second expansion valve14B, the exterior fan15, the interior fan16, the first opening-closing valve17A, the second opening-closing valve17B, the third opening-closing valve17C, the fourth opening-closing valve17D, and the notification unit52. The notification unit52notifies information related to the refrigeration apparatus1to the outside of the refrigeration apparatus1. The notification unit52includes, for example, a display53that shows information related to the refrigeration apparatus1. The notification unit52may include a speaker instead of or in addition to the display53. In this case, the notification unit52may issue notification of information related to the refrigeration apparatus1with sound.

The control device50includes a controller51. The controller51includes, for example, an arithmetic unit that executes a predetermined control program and a storage unit. The arithmetic unit includes, for example, a central processing unit (CPU) or a micro processing unit (MPU). The storage unit stores various control programs and information used for various control processes. The storage unit includes, for example, nonvolatile memory and volatile memory. The controller51controls the compressor11, the expansion valves14A and14B, the exterior fan15, the interior fan16, and the opening-closing valves17A to17D based on detection results of the sensors41to48. The refrigeration apparatus1performs a refrigerating-cooling operation and a defrosting operation using the controller51.

Refrigerating-Cooling Operation

In the refrigerating-cooling operation, the first opening-closing valve17A, the second opening-closing valve17B, and the third opening-closing valve17C are open, and the fourth opening-closing valve17D is closed. The opening degree of each of the first expansion valve14A and the second expansion valve14B is appropriately adjusted. Also, the compressor11, the exterior fan15, and the interior fan16are operated.

During the refrigerating-cooling operation, the refrigerant circulates as indicated by the solid arrows shown inFIG.1. More specifically, a high-pressure gas refrigerant compressed in the compressor11is condensed to become a liquid refrigerant in the condenser12and then is stored in the receiver29. The liquid refrigerant stored in the receiver29flows through the second opening-closing valve17B and the dryer30. The liquid refrigerant is supercooled to become a supercooled liquid refrigerant in the primary passage27aof the supercooling heat exchanger27and flows to the first expansion valve14A. As indicated by the wave arrows shown inFIG.1, some of the liquid refrigerant discharged from the receiver29flows as a supercooling source through the third opening-closing valve17C and the second expansion valve14B to become an intermediate-pressure refrigerant. The intermediate-pressure refrigerant flows to the secondary passage27bof the supercooling heat exchanger27to cool the liquid refrigerant in the primary passage27a. The liquid refrigerant supercooled in the supercooling heat exchanger27is decompressed in the first expansion valve14A and then flows to the evaporator13. In the evaporator13, a low-pressure liquid refrigerant absorbs heat from the air in the storage and evaporates. As a result, the air in the storage is cooled. The low-pressure gas refrigerant evaporated in the evaporator13is drawn into the compressor11and compressed again.

Defrosting Operation

When the refrigerating-cooling operation is continuously performed, frost collects on a surface of, for example, a heat transfer tube of the evaporator13. The frost gradually develops and enlarges. The controller51performs the defrosting operation, that is, an operation for defrosting the evaporator13.

As indicted by the broken arrows shown inFIG.1, the defrosting operation allows a high-temperature high-pressure gas refrigerant that is compressed in the compressor11to flow to the inlet side of the evaporator13through a bypass to defrost the evaporator13. In the defrosting operation, the fourth opening-closing valve17D is open, and the first opening-closing valve17A, the second opening-closing valve17B, the third opening-closing valve17C, and the second expansion valve14B are fully closed. While the compressor11is operated, the exterior fan15and the interior fan16are stopped.

The high-pressure high-temperature gas refrigerant compressed in the compressor11flows through the main passage32and then the fourth opening-closing valve17D and is divided into the first branch passage33and the second branch passage34. The refrigerant divided into the second branch passage34flows through the drain pan heater35. The refrigerant discharged from the drain pan heater35joins the refrigerant that has passed through the first branch passage33and flows to the evaporator13. In the evaporator13, a high-pressure gas refrigerant (so-called hot gas) flows in the heat transfer tube. Thus, in the evaporator13, the frost collected on the heat transfer tube and a fin is gradually heated by the high-temperature gas refrigerant. As a result, the drain pan28gradually receives the frost from the evaporator13. The refrigerant used to defrost the evaporator13is drawn into the compressor11and compressed again. The drain pan28receives, for example, an ice block that falls from the surface of the evaporator13in addition to water, that is, melted frost. The ice block is heated and melted by the refrigerant flowing in the drain pan heater35. The melted water is discharged out of the storage through a predetermined flow passage.

As shown inFIG.2, the control device50further includes an abnormality determination device60that determines whether the compressor11has an abnormality or estimates an abnormality occurrence time of the compressor11. The abnormality of the compressor11includes a decrease in the compression efficiency of the compressor11caused by the refrigerant leak from the compression mechanism of the compressor11and an increase in the supply of current to the compressor11caused by a damaged bearing of the compressor11due to aging and deterioration. The abnormality determination device60monitors a polytropic index of the compressor11to determine whether the compressor11has an abnormality caused by an excessive decrease in the compression efficiency of the compressor11. The abnormality determination device60monitors the supply of current to the compressor11to determine whether the compressor11has an abnormality. The abnormality determination device60estimates a time at which an abnormality of the compressor11will occur based on a change trend of the supply of current to the compressor11. In addition, the abnormality determination device60estimates a time at which an abnormality of the compressor11will occur due to an excessive decrease in the compression efficiency of the compressor11based on a change trend of the polytropic index.

As shown inFIG.3, the abnormality determination device60includes a data obtainment unit61, data storage62, a pre-processing unit63, an abnormality determination unit64, and an output unit65.

The data obtainment unit61is connected to the sensors41to48to communicate with the sensors41to48. The data obtainment unit61receives time series data from the sensors41to48. In an example, each of the sensors41to48outputs a detection result to the abnormality determination device60in each predetermined time TX. An example of the predetermined time TX is one hour. In an example, each of the sensors41to48stores detection results detected in a predetermined sampling cycle for the predetermined time TX and outputs an average of the detection results in the predetermined time TX to the abnormality determination device60. Each of the sensors41to48may output a detection result detected at a clock time specified in each predetermined time TX to the abnormality determination device60.

The data storage62is electrically connected to the data obtainment unit61. The data storage62receives data from the data obtainment unit61. The data storage62stores data from the data obtainment unit61. In an example, the data storage62sequentially stores data from the data obtainment unit61in time order. In the present embodiment, the data storage62is configured to be a memory medium incorporated in the abnormality determination device60. In this case, the data storage62may include, for example, nonvolatile memory and volatile memory. The data storage62may be a memory medium provided outside the abnormality determination device60or outside the refrigeration apparatus1. In this case, the data storage62may include at least one of universe serial bus (USB) memory, a secure digital (SD) memory card, and a hard disk drive (HDD) memory medium.

The pre-processing unit63removes, from the time series data, data that act as noise when determining whether the compressor11has an abnormality or estimating an abnormality occurrence time of the compressor11and replaces the section corresponding to the removed data with alternative data. The pre-processing unit63includes a first processor63aand a second processor63b. The noise data include data having momentary variations that occur, for example, immediately after activation of the compressor11and data in temporally noncontinuous sections.

The first processor63ais electrically connected to the data storage62. The second processor63bis electrically connected to the first processor63a. The first processor63aextracts a section that is replaced with alternative data. Such a section includes, for example, at least one of a section in which the refrigeration apparatus1is stopped, a section immediately after activation of the compressor11, a section immediately after deactivation of the compressor11, or a section immediately after operation of the compressor11is switched. In the present embodiment, the first processor63aextracts all of the section in which the refrigeration apparatus1is stopped, a section immediately after activation of the compressor11, the section immediately after deactivation of the compressor11, and the section immediately after the operation of the compressor11is switched.

The second processor63binputs alternative data into the section extracted by the first processor63a. The alternative data is a value before or after the section extracted by the first processor63aor a predetermined representative value. For example, when the first processor63aextracts the section in which the refrigeration apparatus1is stopped, the second processor63buses a value in one of the sections before and after the section in which the refrigeration apparatus1is stopped as the alternative data. Data in sections being stopped, that is, temporally noncontinuous sections, are assumed to be, for example, zero. When the first processor63aextracts the section immediately after activation of the compressor11, the second processor63buses the value after the section immediately after activation of the compressor11as the alternative data. The value after the section immediately after activation of the compressor11may be an average value of data obtained during a predetermined period after the section immediately after activation of the compressor11or data obtained at a time immediately after the section immediately after activation of the compressor11. When the first processor63aextracts the section immediately after deactivation of the compressor11, the second processor63buses a value in a section before the section immediately after deactivation of the compressor11. The section before the section immediately after deactivation of the compressor11may be the section immediately before deactivation of the compressor11. The value in the section before the section immediately after deactivation of the compressor11may be an average value of data in the section immediately before deactivation of the compressor11or may be data related to time immediately before deactivation of the compressor11. When the first processor63aextracts the section immediately after operation of the compressor11is switched, the second processor63buses a value in one of the sections before and after the section immediately after operation of the compressor11is switched as alternative data. The value in one of the sections before and after the section immediately after operation of the compressor11is switched may be an average value of data in one of the sections before and after the section immediately after operation of the compressor11is switched or may be data related to a predetermined time in one of the sections before and after the section immediately after operation of the compressor11is switched. As the process for calculating alternative data, data obtained before and after the section that is replaced with the alternative data may be interpolated (e.g., linearly interpolated), and the calculated value may be used as the alternative data.

The abnormality determination unit64is electrically connected to the pre-processing unit63. The abnormality determination unit64uses the test data that has been processed by the pre-processing unit63to determine whether the compressor11has an abnormality or estimate an abnormality occurrence time of the compressor11. The abnormality determination unit64includes a calculator66and a determination unit67.

The calculator66calculates a first index value and a second index value to calculate a deviation degree of the compressor11from a normal state. The calculator66calculates the first index value from data related to operation of the refrigeration apparatus1in a first period. The calculator66calculates the second index value from data related to operation of the refrigeration apparatus1in a second period that differs in length from the first period. The calculator66calculates the deviation degree of the compressor11from the normal state based on the first index value and the second index value. In the present embodiment, the calculator66calculates the deviation degree of the compressor11from the normal state based on a deviation degree between the first index value and the second index value. The calculator66outputs the calculation result to the determination unit67.

The determination unit67determines whether the compressor11has an abnormality or estimates an abnormality occurrence time of the compressor11based on the deviation degree of the compressor11from the normal state calculated by the calculator66. The determination unit67outputs the determination result or the estimation result to the output unit65.

The output unit65is electrically connected to the data storage62and the notification unit52. The output unit65outputs the determination result of whether the compressor11has an abnormality or the estimation result of the abnormality occurrence time of the compressor11to the data storage62and the notification unit52. The notification unit52uses, for example, the display53to show the determination result of whether the compressor11has an abnormality or the estimation result of an abnormality occurrence time of the compressor11. The output unit65further includes a wireless communicator including an antenna. The output unit65is configured to communicate with a terminal of a manager (manager terminal70) through the wireless communicator. The output unit65outputs the determination result of whether the compressor11has an abnormality or the estimation result of an abnormality occurrence time of the compressor11to the manager terminal70. The manager terminal70may be a mobile communication device such as a smartphone or a tablet computer or may be a desktop personal computer.

The determination of whether the compressor11has an abnormality and the estimation of abnormality occurrence time of the compressor11, which are performed by the abnormality determination unit64, will now be described in detail.

The calculator66uses data stored in the data storage62and related to operation of the refrigeration apparatus1to calculate the first index value from a moving average of data related to operation of the refrigeration apparatus1in the first period and calculate the second index value from a moving average of data related to operation of the refrigeration apparatus1in the second period. The calculator66calculates the first index value and the second index value using data in the first period and the second period that are before execution of the process. Then, the calculator66calculates the deviation degree between the first index value and the second index value. In the present embodiment, data in the first period include data for one day, and data in the second period include data for ten days. In the present embodiment, a sampling cycle is one hour, and data related to operation of the refrigeration apparatus1is obtained per hour. Hence, data in the first period and data in the second period may be expressed by the number of data sets as well as the length of a period. Data for one day include twenty-four data sets, and data for ten days include two hundred and forty data sets.

The first index value and the second index value include a first example and a second example that are described as follows. In the first example, each of the first index value and the second index value is a polytropic index. In the second example, each of the first index value and the second index value is a compressor current ratio. The compressor current ratio is an example of a compressor current index and is expressed by a ratio of an actual value of current supplied to the compressor11to an estimated value of current supplied to the compressor11. In the present embodiment, the ratio of the actual value of current supplied to the compressor11to the estimated value of current supplied to the compressor11is defined as the compressor current ratio.

The first example of the first index value and the second index value will be described.

The abnormality determination device60calculates data related to operation of the refrigeration apparatus1. The data is, for example, a polytropic index. The polytropic index will be described with reference toFIG.4. In a vapor compression refrigeration cycle such as the refrigeration apparatus1, as shown in a Mollier diagram (pressure-enthalpy chart) ofFIG.4, the refrigerant circulates in the refrigerant circuit20as the refrigerant is compressed from point A to point B in a compression process and then cooled from point B to point C in a condensation process, decompressed from point C to point D in an expansion process, and heated from point D to point A in an evaporation process. In this refrigeration cycle, the compression efficiency of the compressor11is expressed by a polytropic index. The polytropic index is a value calculated from states of the refrigerant at the intake side and the discharge side of the compressor11and shows the relationship between pressure and a specific volume of the refrigerant when compressed. The polytropic index is a value unique to the compressor forming the refrigeration cycle. This value determines a curve of the compression process (inFIG.4, approximately indicated by a straight line).

For example, when the amount of the refrigerant leaked from the high-pressure side to the low-pressure side in the compressor11is increased due to deterioration of the compressor11, the value of the polytropic index changes (increases). This results in a change in the slope of the compression process curve. InFIG.4, the compression process curve indicated by the solid line shows an initial compression state at installation. The compression process curve indicated by the broken line shows a compression state when the compressor11has deteriorated. As shown in the compression process shown inFIG.4, when the compressor11has deteriorated, in the compression process, the refrigerant is compressed from point A toward point B′, which corresponds to a greater enthalpy than point B. Thus, deterioration of the compressor11increases the slope of the compression process curve.

A polytropic index is typically calculated by the following equation.

n=11-log⁢P⁢⁢1/P⁢⁢2⁢(T⁢1T⁢⁢2)[Equation⁢⁢1]

In Equation 1, “n” denotes a polytropic index, “T1” denotes a temperature of the refrigerant at the intake side of the compressor11, “T2” denotes a temperature of the refrigerant at the discharge side of the compressor11, “P1” denotes pressure of the refrigerant at the intake side of the compressor11, and “P2” denotes pressure of the refrigerant at the discharge side of the compressor11. The abnormality determination device60calculates temperature T1from a signal of the intake temperature sensor43, temperature T2from a signal of the discharge temperature sensor41, pressure P1from a signal of the intake pressure sensor44, and pressure P2from a signal of the discharge pressure sensor42. When the abnormality determination device60does not calculate temperatures T1and T2and pressures P1and P2, the controller51may calculate temperatures T1and T2and pressures P1and P2. In this case, when the controller51outputs temperatures T1and T2and pressures P1and P2to the abnormality determination device60, the abnormality determination device60obtains temperatures T1and T2and pressures P1and P2.

The calculator66calculates a polytropic index in the first period (hereafter, referred to as “first polytropic index”) as the first index value and calculates a polytropic index in the second period (hereafter, referred to as “second polytropic index”) as the second index value.FIG.5Ais a graph showing an example of changes in the first polytropic index and the second polytropic index. As shown inFIG.5A, on or before September 12th, the first polytropic index is substantially equal to the second polytropic index. Between September 12th and October 3rd, the deviation degree gradually increases. From October 3rd, the deviation degree increases as time elapses.

The calculator66calculates, for example, the deviation degree between the first polytropic index and the second polytropic index. In the present embodiment, the deviation degree between the first polytropic index and the second polytropic index is expressed by a ratio of the first polytropic index to the second polytropic index. As the ratio increases, the deviation degree between the first polytropic index and the second polytropic index increases. The deviation degree between the first polytropic index and the second polytropic index may be expressed by a difference between the first polytropic index and the second polytropic index. As the difference increases, the deviation degree between the first polytropic index and the second polytropic index increases.FIG.5Bis a graph showing an example of changes in the deviation degree between the first polytropic index and the second polytropic index. As shown inFIG.5B, on or before September 12th, the deviation degree between the first polytropic index and the second polytropic index is substantially 1.00. Between September 12th and October 3rd, the deviation degree between the first polytropic index and the second polytropic index gradually increases. From October 3rd, the deviation degree increases more steeply.

When the deviation degree between the first polytropic index and the second polytropic index is greater than or equal to a first threshold value X1, the determination unit67determines that the compressor11has an abnormality. The first threshold value X1is set in advance by experiments or the like and is used to determine that the compression efficiency of the compressor11is excessively decreased.

The determination unit67estimates an abnormality occurrence time of the compressor11based on a change trend of the deviation degree between the first polytropic index and the second polytropic index. More specifically, the calculator66calculates a deviation degree between the first polytropic index and the second polytropic index for each day and outputs the deviation degree to the determination unit67. The determination unit67obtains a change trend of the deviation degree based on the deviation degree between the first polytropic index and the second polytropic index of each day. The determination unit67estimates an abnormality occurrence time of the compressor11based on information indicating that the deviation degree has an increasing trend and the slope of the deviation degree. More specifically, the determination unit67estimates a time in which the deviation degree reaches the first threshold value X1based on the slope of the deviation degree between the first polytropic index and the second polytropic index. The determination unit67may calculate the slope of the deviation degree using, for example, regression analysis or a straight line that connects deviation degrees in predetermined two periods. In an example, as shown inFIG.5B, the determination unit67estimates a deviation degree from October 25th based on changes in the deviation degree between the first polytropic index and the second polytropic index obtained until October 24th (broken line inFIG.5B). The determination unit67estimates an abnormality occurrence time of the compressor11based on a comparison of the first threshold value X1with changes in the deviation degree from October 25th.

Procedures of determining whether the compressor11has an abnormality or estimating an abnormality occurrence time of the compressor11performed by the abnormality determination device60will be described in detail with reference toFIG.6. This process is executed, for example, at least one of when there is a user request, when the transporting refrigeration apparatus1or the abnormality determination device60is powered on, when transportation of the refrigeration apparatus1is completed, or when the pre-trip inspection of the refrigeration apparatus1is conducted. In the present embodiment, at each of when there is a user request, when the refrigeration apparatus1or the abnormality determination device60is powered on, when transportation of the refrigeration apparatus1is completed, and when the pre-trip inspection of the refrigeration apparatus1is conducted, the abnormality determination device60determines whether the compressor11has an abnormality or estimates an abnormality occurrence time of the compressor11.

In step S11, the abnormality determination device60calculates a first polytropic index and a second polytropic index from data related to operation of the refrigeration apparatus1and then proceeds to step S12. In step S12, the abnormality determination device60calculates a deviation degree between the first polytropic index and the second polytropic index and then proceeds to step S13.

In step S13, the abnormality determination device60determines whether the deviation degree between the first polytropic index and the second polytropic index is greater than or equal to the first threshold value X1. When the affirmative determination is made in step S13, the abnormality determination device60proceeds to step S14to determine that the compressor11has an abnormality and then proceeds to step S15. In step S15, the abnormality determination device60transmits the determination result to at least one of the display53or the manager terminal70and then temporarily ends the process. In step S15, the display53and the manager terminal70issue notification of the determination result of whether the compressor11has an abnormality or notification of the estimation result of an abnormality occurrence time of the compressor11at least one of when there is a user request, when the refrigeration apparatus1or the abnormality determination device60is powered on, when transportation of the refrigeration apparatus1is completed, or when the pre-trip inspection of the refrigeration apparatus1is conducted. In the present embodiment, the display53and the manager terminal70issue notification of the determination result of whether the compressor11has an abnormality or notification of the estimation result of an abnormality occurrence time of the compressor11each of when there is a user request, when the refrigeration apparatus1or the abnormality determination device60is powered on, when transportation of the refrigeration apparatus1is completed, and when the pre-trip inspection of the refrigeration apparatus1is conducted. In step S15, the result may be transmitted to the notification unit52instead of the display53. When the notification unit52includes a speaker, the notification unit52may issue, using the speaker, notification of the determination result of whether the compressor11has an abnormality or notification of the estimation result of an abnormality occurrence time of the compressor11.

When a negative determination is made in step S13, the abnormality determination device60proceeds to step S16to calculate a change trend of the deviation degree between the first polytropic index and the second polytropic index and then proceeds to step S17.

In step S17, the abnormality determination device60estimates an abnormality occurrence time of the compressor11based on the slope of the deviation degree between the first polytropic index and the second polytropic index and then proceeds to step S18. In step S18, the abnormality determination device60transmits the estimation result to at least one of the display53or the manager terminal70and then temporarily ends the process. As described above, in the flowchart shown inFIG.6, after determining whether the compressor11has an abnormality, the abnormality determination device60estimates an abnormality occurrence time of the compressor11.

The second example of the first index value and the second index value will now be described.

The calculator66calculates an estimated value of current supplied to the compressor11and an actual value of current supplied to the compressor11and calculates the compressor current ratio as the ratio of the actual value of current supplied to the compressor11to the estimated value of current supplied to the compressor11.

The calculator66calculates the estimated value of current supplied to the compressor11from, for example, at least one of the condensation temperature of the refrigerant circuit20, the evaporation temperature of the refrigerant circuit20, the operating frequency of the compressor11, or the rotational speed of the compressor11.

The calculator66calculates the actual value of current supplied to the compressor11in the compressor current ratio from a signal of the current sensor45. The actual value of current supplied to the compressor11increases relative to the estimated value of current supplied to the compressor11, for example, when the amount of the refrigerant leaked from the high-pressure side to the low-pressure side in the compression mechanism of the compressor11is increased due to deterioration of the compressor11or when the rotation resistance of the rotor of the motor in the compressor11is increased due to deterioration of the bearing (rolling bearing) that rotationally supports the rotor. Thus, the deviation degree of the actual value of current supplied to the compressor11from the estimated value of current supplied to the compressor11is correlated with the deterioration degree of the compressor11.

The calculator66calculates a compressor current ratio in the first period (hereafter, referred to as “first compressor current ratio”) as the first index value and calculates a compressor current ratio in the second period (hereafter, referred to as “second compressor current ratio”) as the second index value.FIG.7Ais a graph showing an example of changes in the first compressor current ratio and the second compressor current ratio. As shown inFIG.7A, on or before September 12th, the first compressor current ratio is equal to the second compressor current ratio. Between September 12th and October 3rd, the deviation degree gradually increases. From October 3rd, the deviation degree increases as time elapses.

The calculator66calculates, for example, the deviation degree between the first compressor current ratio and the second compressor current ratio. In the present embodiment, the deviation degree between the first compressor current ratio and the second compressor current ratio is expressed by a ratio of the first compressor current ratio to the second compressor current ratio. As the ratio increases, the deviation degree between the first compressor current ratio and the second compressor current ratio increases. The deviation degree between the first compressor current ratio and the second compressor current ratio may be expressed by a difference between the first compressor current ratio and the second compressor current ratio. As the difference increases, the deviation degree between the first compressor current ratio and the second compressor current ratio increases.FIG.7Bis a graph showing an example of changes in the deviation degree between the first compressor current ratio and the second compressor current ratio. As shown inFIG.7B, on or before September 12th, the deviation degree between the first compressor current ratio and the second compressor current ratio is substantially 1.00. Between September 12th and October 3rd, the deviation degree between the first compressor current ratio and the second compressor current ratio gradually increases. From October 3rd, the deviation degree increases more steeply.

When the deviation degree between the first compressor current ratio and the second compressor current ratio is greater than or equal to a second threshold value X2, the determination unit67determines that the compressor11has an abnormality. The second threshold value X2is set in advance by experiments or the like and is used to determine that the compressor11has an abnormality due to deterioration of the compressor11.

The determination unit67estimates an abnormality occurrence time of the compressor11based on a change trend of the deviation degree between the first compressor current ratio and the second compressor current ratio. More specifically, the calculator66calculates, for example, a deviation degree between the first compressor current ratio and the second compressor current ratio for each day and outputs the deviation degree to the determination unit67. The determination unit67obtains a change trend of the deviation degree, for example, based on the deviation degree between the first compressor current ratio and the second compressor current ratio of each day. The determination unit67estimates an abnormality occurrence time of the compressor11based on information indicating that the deviation degree has an increasing trend and the slope of the deviation degree. More specifically, the determination unit67estimates a time in which the deviation degree reaches the second threshold value X2based on the slope of the deviation degree between the first compressor current ratio and the second compressor current ratio. In an example, as shown inFIG.7B, the determination unit67estimates a deviation degree from October 25th based on changes in the deviation degree between the first compressor current ratio and the second compressor current ratio obtained until October 24th (broken line inFIG.7B). The determination unit67estimates an abnormality occurrence time of the compressor11based on a comparison of the second threshold value X2with changes in the deviation degree from October 25th.

Procedures of determination of whether the compressor11has an abnormality and estimation of an abnormality occurrence time of the compressor11performed by the abnormality determination device60will be described in detail with reference toFIG.8. This process is executed, for example, at least one of when there is a user request, when the transporting refrigeration apparatus1or the abnormality determination device60is powered on, when transportation of the refrigeration apparatus1is completed, or when the pre-trip inspection of the refrigeration apparatus1is conducted. In the present embodiment, at each of when there is a user request, when the refrigeration apparatus1or the abnormality determination device60is powered on, when transportation of the refrigeration apparatus1is completed, and when the pre-trip inspection of the refrigeration apparatus1is conducted, the abnormality determination device60determines whether the compressor11has an abnormality or estimates an abnormality occurrence time of the compressor11.

In step S21, the abnormality determination device60calculates a first compressor current ratio and a second compressor current ratio from data related to operation of the refrigeration apparatus1and then proceeds to step S22. In step S22, the abnormality determination device60calculates a deviation degree between the first compressor current ratio and the second compressor current ratio and then proceeds to step S23.

In step S23, the abnormality determination device60determines whether the deviation degree between the first compressor current ratio and the second compressor current ratio is greater than or equal to the second threshold value X2. When an affirmative determination is made in step S23, the abnormality determination device60proceeds to step S24to determine that the compressor11has an abnormality and then proceeds to step S25. In step S25, the abnormality determination device60transmits the determination result to at least one of the display53or the manager terminal70and then temporarily ends the process. In step S25, the display53and the manager terminal70issue notification of the determination result of whether the compressor11has an abnormality or notification of the estimation result of an abnormality occurrence time of the compressor11at least one of when there is a user request, when the refrigeration apparatus1or the abnormality determination device60is powered on, when transportation of the refrigeration apparatus1is completed, or when the pre-trip inspection of the refrigeration apparatus1is conducted. In the present embodiment, the display53and the manager terminal70issue notification of the determination result of whether the compressor11has an abnormality or notification of the estimation result of an abnormality occurrence time of the compressor11each of when there is a user request, when the refrigeration apparatus1or the abnormality determination device60is powered on, when transportation of the refrigeration apparatus1is completed, and when the pre-trip inspection of the refrigeration apparatus1is conducted. In step S25, the result may be transmitted to the notification unit52instead of the display53. When the notification unit52includes a speaker, the notification unit52may issue, using the speaker, notification of the determination result of whether the compressor11has an abnormality or notification of the estimation result of an abnormality occurrence time of the compressor11.

When a negative determination is made in step S23, the abnormality determination device60proceeds to step S26to calculate a change trend of the deviation degree between the first compressor current ratio and the second compressor current ratio and then proceeds to step S27.

In step S27, the abnormality determination device60estimates an abnormality occurrence time of the compressor11based on a slope of changes in the deviation degree between the first compressor current ratio and the second compressor current ratio and then proceeds to step S28. In step S28, the abnormality determination device60transmits the estimation result to at least one of the display53or the manager terminal70and then temporarily ends the process. As described above, in the flowchart shown inFIG.8, after determining whether the compressor11has an abnormality, the abnormality determination device60estimates an abnormality occurrence time of the compressor11.

The method for determining an abnormality of the compressor11executed by the abnormality determination device60and described above includes a data storing step, a first calculating step, a second calculating step, and a determining step. The steps will be described below.

The data storing step is a step of storing data related to operation of the refrigeration apparatus1. In an example, the data storing step stores data related to operation of the refrigeration apparatus1and obtained from the data obtainment unit61in the data storage62as time series data.

The first calculating step is a step of calculating the first index value from data related to operation of the refrigeration apparatus1in the first period and calculating the second index value from data related to operation of the refrigeration apparatus1in the second period. In an example, the first calculating step is executed by the calculator66. The first calculating step is a step of calculating the first index value from a moving average of data related to operation of the refrigeration apparatus1in the first period and calculating the second index value from a moving average of data related to operation of the refrigeration apparatus1in the second period. In an example, the first calculating step includes a pre-processing step that removes data that act as noise when determining whether the compressor11has an abnormality or estimating an abnormality occurrence time of the compressor11and replaces it with alternative data with the pre-processing unit63. The relationship of the first calculating step withFIGS.6and8is that step S11inFIG.6and step S21inFIG.8correspond to the first calculating step.

The second calculating step is a step of calculating a deviation degree of the compressor11from the normal state based on the first index value and the second index value. In an example, the second calculating step is executed by the calculator66. The relationship of the second calculating step withFIGS.6and8is that step S12inFIG.6and step S22inFIG.8correspond to the second calculating step.

The determining step is a step of determining whether the compressor11has an abnormality or estimating an abnormality occurrence time of the compressor11based on the deviation degree of the compressor11from the normal state. In an example of the determining step, when the second index value refers to the normal state of the compressor11and the deviation degree of the first index value from the second index value is greater than or equal to a threshold value, it is determined that the compressor11has an abnormality. In the determining step, a time at which the deviation degree reaches the threshold value is estimated based on a change trend of the deviation degree of the first index value from the second index value, so that the abnormality occurrence time of the compressor11is estimated. The relationship of the determining step withFIGS.6and8is that steps S13to S18inFIG.6and steps S23to S28inFIG.8correspond to the determining step.

The operation of the present embodiment will now be described.

The abnormality determination device60calculates the second index value from a moving average of data related to operation of the refrigeration apparatus1in the second period and uses the calculated second index value as reference. In the present embodiment, data in the second period is related to operation of the refrigeration apparatus1obtained during a long period of ten days to thirty days and thus is subtly affected by variations related to operation of the refrigeration apparatus1obtained during a short period such as one day.

The abnormality determination device60also calculates the first index value from a moving average of data related to operation of the refrigeration apparatus1in the first period. In the present embodiment, data in the first period is related to operation of the refrigeration apparatus1in a short period, that is, one day, and thus is greatly affected by recent variations related to operation of the refrigeration apparatus1.

As described above, the second index value, which is subtly affected by recent variations related to operation of the refrigeration apparatus1, is used as reference to monitor how much the first index value, which is greatly affected by variations related to operation of the refrigeration apparatus1, is deviated from the second index value. This facilitates extraction of variations related to operation of the refrigeration apparatus1. With this configuration, when the compressor11has an abnormality, the first index value is prominently deviated from the second index value so that the abnormality determination device60determines that the compressor11has an abnormality. In addition, the abnormality determination device60obtains a change trend of the deviation degree of the first index value from the second index value and estimates changes in the deviation degree to estimate an abnormality occurrence time of the compressor11.

The present embodiment has the following advantages.

(1) In data related to operation of the refrigeration apparatus1, the calculator66calculates a first index value from data related to operation of the refrigeration apparatus1in the first period and calculates a second index value from data related to operation of the refrigeration apparatus1in the second period that differs length from the first period. Then, the calculator66calculates a deviation state of the compressor11from the normal state based on the first index value and the second index value. The determination unit67determines whether the compressor11has an abnormality or estimates an abnormality occurrence time of the compressor11based on the deviation degree of the compressor11from the normal state. With this configuration, the deviation state of the compressor11from the normal state is calculated based on the state of difference between the first index value and the second index value calculated using data related to operation of the refrigeration apparatus1including the pre-trip inspection operation of the refrigeration apparatus1and normal operations of the refrigeration apparatus1such as the cooling operation and the defrosting operation. The determination of whether the compressor11has an abnormality or the estimation of an abnormality occurrence time is performed based on the deviation state of the compressor11from the normal state. Thus, the determination of whether the compressor11has an abnormality or the estimation of an abnormality occurrence time is performed without performing a special operation for determining an abnormality of the compressor11.

(2) The second index value, which is calculated from the long second period, is subtly affected by variations related to operation of the refrigeration apparatus1. The first index value, which is calculated from the short first period, is greatly affected by variations related to operation of the refrigeration apparatus1. In the present embodiment, the calculator66calculates the first index value and the second index value and calculates the deviation degree of the compressor11from the normal state based on the deviation degree between the first index value and the second index value. This facilitates extraction of variations in operation of the refrigeration apparatus1. Whether the compressor11has an abnormality is determined or an abnormality occurrence time of the compressor11is estimated based on the variations in operation of the refrigeration apparatus1.

(3) The first index value is calculated from a moving average of data related to operation of the refrigeration apparatus1in the first period. The second index value is calculated from a moving average of data related to operation of the refrigeration apparatus1in the second period. With this configuration, whether the compressor11has an abnormality is determined or an abnormality occurrence time of the compressor11is estimated based on a deviation degree between variations in operation of the refrigeration apparatus1during a long period and variations in operation of the refrigeration apparatus1during a short period.

(4) The first index value and the second index value include a polytropic index. This allows for determination of whether the compressor11has an abnormality or estimation of an abnormality occurrence time of the compressor11based on variations related to the compression process of the compressor11.

(5) The first index value and the second index value include the compressor current ratio. This allows for determination of whether the compressor11has an abnormality due to aging and deterioration of the compressor11such as deterioration of a bearing of the compressor11or for estimation of an abnormality occurrence time of the compressor11.

(6) The pre-processing unit63eliminates data related to operation of the refrigeration apparatus1and acting as noise when determining whether the compressor11has an abnormality or estimating an abnormality occurrence time of the compressor11and replaces it with alternative data. The determination of whether the compressor11has an abnormality or the estimation of an abnormality occurrence time of the compressor11is performed with high accuracy.

(7) When the first processor63aextracts a section immediately after activation of the compressor11, the second processor63buses a value after the section immediately after activation of the compressor11as the alternative data. When the first processor63aextracts the section immediately after deactivation of the compressor11, the second processor63buses a value in a section before the section immediately after deactivation of the compressor11. When the first processor63aextracts the section immediately after operation of the compressor11is switched, the second processor63buses a value in one of the sections before and after the section immediately after operation of the compressor11is switched as alternative data. This configuration uses data temporally close to the section extracted by the first processor63aas alternative data, so that the deviation degree of the alternative data from the actual data related to operation of the refrigeration apparatus1is decreased. As a result, the determination of whether the compressor11has an abnormality and the estimation of an abnormality occurrence time of the compressor11are performed with high accuracy.

(8) The notification unit52indicates occurrence of an abnormality of the compressor11or an abnormality occurrence time of the compressor11in the display53of the refrigeration apparatus1or the manager terminal70. This allows the manger or the operator of the refrigeration apparatus1to recognize the abnormality of the compressor11or the abnormality occurrence time.

MODIFIED EXAMPLES

The description related to the above embodiments exemplifies, without any intention to limit, applicable forms of an abnormality determination device, a refrigeration apparatus including the abnormality determination device, and a method for determining an abnormality of a compressor according to the present disclosure. The abnormality determination device, the refrigeration apparatus including the abnormality determination device, and the method for determining an abnormality of the compressor according to the present disclosure can be applicable to, for example, modified examples of the embodiments that are described below and combinations of at least two of the modified examples that do not contradict each other. In the following modified examples, the same reference characters are given to those elements that are the same as the corresponding elements of the above embodiment. Such elements will not be described in detail.

In the embodiment, the deviation degree between the first index value and the second index value is expressed by the ratio of the first index value to the second index value. However, there is no limitation to such a configuration. The process of calculating the deviation degree between the first index value and the second index value may be changed in any manner. In an example, the calculator66may calculate the deviation degree between the first index value and the second index value based on at least one of a standard deviation, skewness, likelihood, kurtosis, or an average that is obtained using the first index value and the second index value.

In the embodiment, the abnormality determination device60performs both determination of whether the compressor11has an abnormality and estimation of an abnormality occurrence time of the compressor11. Instead, the abnormality determination device60may perform only determination of whether the compressor11has an abnormality. Alternatively, when the deviation degree between the first index value and the second index value is less than the first threshold value X1(second threshold value X2), the abnormality determination device60may perform only estimation of an abnormality occurrence time of the compressor11. In this case, the abnormality determination device60may omit determination of whether the compressor11has an abnormality.

In the embodiment, the pre-processing unit63removes, from time series data, data that act as noise when determining whether the compressor11has an abnormality or estimating an abnormality occurrence time of the compressor11, and replaces the section corresponding to the removed data with alternative data. However, there is no limitation to such a configuration. The pre-processing unit63may only remove, from time series data, data that act as noise when determining whether the compressor11has an abnormality or estimating an abnormality occurrence time of the compressor11. This configuration accurately determines whether the compressor11has an abnormality or estimates an abnormality occurrence time of the compressor11.

In the embodiment, the abnormality determination device60uses one of the polytropic index and the compressor current ratio to determine whether the compressor11has an abnormality or estimate an abnormality occurrence time of the compressor11. However, there is no limitation to such a configuration. For example, the abnormality determination device60may use both the polytropic index and the compressor current ratio to determine whether the compressor11has an abnormality or estimate an abnormality occurrence time of the compressor11.

In the embodiment, the first index value and the second index value may be calculated from the estimated value of current supplied to the compressor11or the actual value of current supplied to the compressor11instead of the compressor current ratio. In an example, the calculator66calculates the first index value from a moving average of estimation values of current supplied to the compressor11in the first period and calculates the second index value from a moving average of estimation values of current supplied to the compressor11in the second period. In an example, the calculator66calculates the first index value from a moving average of actual values of current supplied to the compressor11in the first period and calculates the second index value from a moving average of actual values of current supplied to the compressor11in the second period.

In the embodiment, the data storage62may be an external server of the refrigeration apparatus1connected to the refrigeration apparatus1to communicate with the refrigeration apparatus1. An example of the server includes a cloud server. More specifically, the abnormality determination device60transmits data obtained in the data obtainment unit61to the server so that the server stores the data.

In the embodiment, the abnormality determination device60and the notification unit52are separately arranged. Instead, the abnormality determination device60may include the notification unit52.

In the embodiment, the refrigeration apparatus1is configured to be transported. However, the configuration of a refrigeration apparatus is not limited to this. For example, a refrigeration apparatus may be used for a stationary storage. When the refrigeration apparatus1is used as a refrigeration apparatus other than a transporting refrigeration apparatus, the abnormality determination device60determines whether the compressor11has an abnormality or estimates an abnormality occurrence time of the compressor11at least one of when there is a user request, when the refrigeration apparatus1or the abnormality determination device60is powered on, or when the pre-trip inspection of the refrigeration apparatus1is conducted. In addition, the notification unit52issues notification of a determination result of whether the compressor11has an abnormality or notification of an estimation time of an abnormality occurrence time at least one of when there is a user request, when the refrigeration apparatus1or the abnormality determination device60is powered on, or when the pre-trip inspection of the refrigeration apparatus1is conducted.

In the embodiment, the refrigeration apparatus1is configured to be installed on a container. However, the configuration of a refrigeration apparatus is not limited to this. For example, as shown inFIG.9, a refrigeration apparatus may be used as an air conditioner80. The air conditioner80includes a refrigerant circuit90in which an outdoor unit80A and a wall-mounted indoor unit80B are connected by a refrigerant pipe91. The outdoor unit80A is arranged outdoors. The indoor unit80B is installed on an indoor wall surface.

The outdoor unit80A includes a compressor81having a variable displacement varied by a change in an operating frequency, a four-way switching valve82, an outdoor heat exchanger83, an expansion valve84, an outdoor fan85, and an outdoor control device86. The compressor81is, for example, a rocking piston compressor and includes, for example, a compression mechanism, a motor, and a crankshaft that transmits driving power of the motor to the compression mechanism. The outdoor heat exchanger83exchanges heats between the outside air and the refrigerant and may be, for example, a fin-and-tube heat exchanger. The expansion valve84is, for example, an electronic expansion valve. The outdoor fan85includes a motor, which is a drive source having a changeable number of revolutions, and an impeller connected to an output shaft of the motor. An example of the impeller is a propeller fan. When the impeller is rotated by the motor, the outdoor fan85generates an airflow of outdoor air flowing through the outdoor heat exchanger83. The outdoor control device86is electrically connected to the motor of the compressor81, the four-way switching valve82, the expansion valve84, and the motor of the outdoor fan85to control their operations.

The indoor unit80B includes an indoor heat exchanger87, an indoor fan88, and an indoor control device89. The indoor heat exchanger87exchanges heat between the inside air and the refrigerant and may be, for example, a fin-and-tube heat exchanger. The indoor fan88includes a motor, which is a drive source having a changeable number of revolutions, and an impeller connected to an output shaft of the motor. An example of the impeller is a cross-flow fan. The indoor control device89is electrically connected to the indoor fan88to control operation of the indoor fan88.

The refrigerant circuit90is formed by connecting the compressor81, the four-way switching valve82, the outdoor heat exchanger83, and the expansion valve84to the indoor heat exchanger87and an accumulator81awith the refrigerant pipe91as a loop. The refrigerant circuit90is configured to execute a vapor compression refrigeration cycle that reversibly circulates the refrigerant by switching the four-way switching valve82.

More specifically, when the four-way switching valve82is switched to a cooling mode connection state (illustrated with solid line), the refrigerant circuit90forms a cooling cycle in which the refrigerant circulates in the order of the compressor81, the four-way switching valve82, the outdoor heat exchanger83, the expansion valve84, the indoor heat exchanger87, the four-way switching valve82, the accumulator81a, and the compressor81. As a result, the air conditioner80performs a cooling operation in which the outdoor heat exchanger83acts as a condenser, and the indoor heat exchanger87acts as an evaporator. When the four-way switching valve82is switched to a heating mode connection state (illustrated with broken lines), the refrigerant circuit90forms a heating cycle in which the refrigerant circulates in the order of the accumulator81a, the compressor81, the four-way switching valve82, the indoor heat exchanger87, the expansion valve84, the outdoor heat exchanger83, the four-way switching valve82, and the compressor81. As a result, the air conditioner80performs a heating operation in which the indoor heat exchanger87acts as a condenser and the outdoor heat exchanger83acts as an evaporator.

In the air conditioner80, for example, the abnormality determination device60(not shown inFIG.9) is arranged on one of the outdoor control device86and the indoor control device89. The notification unit52(not shown inFIG.9) is arranged on, for example, a remote controller of the air conditioner80.

In the embodiment, the refrigeration apparatus1includes the abnormality determination device60. However, the refrigeration apparatus1is not limited to this configuration. For example, the abnormality determination device60may be omitted from the refrigeration apparatus1. The abnormality determination device60and the refrigeration apparatus1may be separately arranged. In an example, the abnormality determination device60may be arranged on a server configured to communicate with the refrigeration apparatus1. In this case, the refrigeration apparatus1communicates with the abnormality determination device60to obtain a determination result of whether the compressor11has an abnormality and an estimation result of an abnormality occurrence time of the compressor11.

While the embodiments of the device have been described herein above, it is to be appreciated that various changes in form and detail may be made without departing from the spirit and scope of the device presently or hereafter claimed.