GB2553972A

GB2553972A - Refrigeration cycle device, remote monitoring system, remote monitoring device, and abnormality determination method

Info

Publication number: GB2553972A
Application number: GB1716771.9A
Authority: GB
Inventors: Nakamura Takaharu; Saito Makoto; Toyoshima Masaki
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2015-07-09
Filing date: 2015-07-09
Publication date: 2018-03-21
Anticipated expiration: 2035-07-09
Also published as: WO2017006474A1; GB201716771D0; GB2553972B; JPWO2017006474A1; JP6403887B2

Abstract

This refrigeration cycle device is equipped with: a refrigeration circuit which includes a compressor, a condenser, a throttle device, and an evaporator; a control unit which controls the refrigeration circuit; and an abnormality determination unit which determines the presence or absence of abnormalities in the refrigeration circuit. The control unit drives the compressor, and performs special operation for stopping the compressor if a predetermined time has elapsed or if the pressure of a refrigerant on the intake side of the compressor decreases to a predetermined value. The abnormality determination unit determines the presence or absence of abnormalities in the refrigeration circuit after the special operation.

Description

(54) Title of the Invention: Refrigeration cycle device, remote monitoring system, remote monitoring device, and abnormality determination method

Abstract Title: Refrigeration cycle device, remote monitoring system, remote monitoring device, and abnormality determination method (57) This refrigeration cycle device is equipped with: a refrigeration circuit which includes a compressor, a condenser, a throttle device, and an evaporator; a control unit which controls the refrigeration circuit; and an abnormality determination unit which determines the presence or absence of abnormalities in the refrigeration circuit. The control unit drives the compressor, and performs special operation for stopping the compressor if a predetermined time has elapsed or if the pressure of a refrigerant on the intake side of the compressor decreases to a predetermined value. The abnormality determination unit determines the presence or absence of abnormalities in the refrigeration circuit after the special operation.

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DESCRIPTION

Title of Invention

REFRIGERATION CYCLE APPARATUS, REMOTE MONITORING SYSTEM, REMOTE MONITORING APPARATUS, AND FAULT DETERMINATION METHOD Technical Field [0001]

The present invention relates to a refrigeration cycle apparatus, a remote monitoring system, a remote monitoring apparatus, and a method of determining a fault, each having a function to determine the presence of a fault, such as a leakage of refrigerant.

Background Art [0002]

In a conventional refrigeration cycle apparatus, a leakage of refrigerant may occur due to insufficient fastening of a connecting point of pipes or other parts, or due to damage in a pipe. Such a leakage of refrigerant causes lowering of performance of the refrigeration cycle apparatus or causes damage to a component device. Consequently, refrigeration cycle apparatuses equipped with a function to detect a leakage of refrigerant have been proposed.

[0003]

For example, Patent Literature 1 describes a method of determining whether a leakage of refrigerant is present by storing an outside air temperature and a discharge temperature of a compressor of an initial stage, and comparing an outside air temperature and a discharge temperature of the compressor of a subsequent time with the stored outside air temperature and discharge temperature of the compressor of the initial stage. Furthermore, Patent Literature 2 describes a method of determining that a leakage of refrigerant is present when, at a startup of a refrigeration cycle, the pressure of refrigerant is lower than a balanced pressure that is obtained during stoppage of a refrigeration cycle by a predetermined value or more, and a method of determining that a leakage of refrigerant is present when the pressure of refrigerant drops rapidly during a normal operation.

Citation List

Patent Literature [0004]

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2013-204871

Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2000-320936 Summary of Invention Technical Problem [0005]

In the method described in Patent Literature 1, determination ofthe presence of a leakage of refrigerant is made by comparing the discharge temperatures when the outside air temperature is the same as the outside air temperature of the initial stage. However, the discharge temperature at the startup of the compressor varies depending on the distribution of refrigerant amount in the refrigerant circuit immediately before the startup. For example, when a small amount of liquid refrigerant is present in a condenser at a stoppage of operation, the discharge temperature at the subsequent startup becomes high. Consequently, even when the outside air temperatures are the same, discharge temperatures may vary depending on the distribution of refrigerant amount, and as a result, a leakage of refrigerant may not be detected correctly. In addition, in Patent Literature 2, no method is described to determine fixed conditions under which the presence of a leakage of refrigerant is determined. Furthermore, it is preferable that determination be made under fixed conditions not only when the presence of a leakage of refrigerant is determined but also when an occurrence of a fault in a compressor is determined.

Object of Invention [0006]

To solve the abovementioned problems, the present invention provides a refrigeration cycle apparatus, a remote monitoring system, a remote monitoring apparatus, and a fault determination method capable of improving the accuracy in determination of a fault, such as a leakage of refrigerant.

Solution to Problem [0007]

A refrigeration cycle apparatus according to one embodiment of the present invention includes a refrigerant circuit having a compressor, a condenser, an expansion device, and an evaporator, a controller for controlling the refrigerant circuit, and a fault determiner for determining whether the refrigerant circuit has a fault. The controller performs a special operation driving and stopping the compressor, the special operation stopping the compressor in response to an event including one of elapse of a predetermined time, and decreasing, to a predetermined value, the pressure of refrigerant at a suction side of the compressor. The fault determiner determines whether the refrigerant circuit has a fault after the special operation.

[0008]

A remote monitoring system according to one embodiment of the present invention includes a refrigeration cycle apparatus and a remote monitoring apparatus communicating with the refrigeration cycle apparatus. The refrigeration cycle apparatus includes a refrigerant circuit having a compressor, a condenser, an expansion device, and an evaporator, and a communicator for communicating with the remote monitoring apparatus. The remote monitoring apparatus includes a communicator for communicating with the refrigeration cycle apparatus, a controller for controlling the refrigerant circuit via the communicator, and a fault determiner for determining whether the refrigerant circuit has a fault. The controller performs a special operation driving and stopping the compressor, the special operation stopping the compressor in response to an event including one of elapse of a predetermined time, and decreasing, to a predetermined value, the pressure of refrigerant at a suction side of the compressor. The fault determiner determines whether the refrigerant circuit has a fault after the special operation.

[0009]

A remote monitoring apparatus according to one embodiment of the present invention includes a communicator for communicating with a refrigeration cycle apparatus, a controller for controlling a refrigerant circuit for the refrigeration cycle apparatus via the communicator, and a fault determiner for determining whether the refrigerant circuit has a fault. The controller performs a special operation driving and stopping the compressor of the refrigerant circuit, the special operation stopping the compressor in response to an event including one of elapse of a predetermined time, and decreasing, to a predetermined value, the pressure of refrigerant at a suction side of the compressor. The fault determiner determines whether the refrigerant circuit has a fault after the special operation.

[0010]

A fault determination method according to one embodiment of the present invention is a method of determining whether a fault is present in a refrigerant circuit having a compressor, a condenser, an expansion device, and an evaporator. The fault determination method includes performing a special operation driving and stopping the compressor, the special operation stopping the compressor in response to an event including one of elapse of a predetermined time, and decreasing, to a predetermined value, the pressure of refrigerant at a suction side of the compressor, and determining whether the refrigerant circuit has a fault after the special operation. Advantageous Effects of Invention [0011]

In the refrigeration cycle apparatus, the remote monitoring system, the remote monitoring apparatus, and the fault determination method of embodiments of the present invention, by performing a special operation driving and stopping a compressor, the special operation stopping the compressor in response to an event including one of elapse of a predetermined time, and decreasing, to a predetermined value, the pressure of refrigerant on the suction side of the compressor, and by determining whether a fault is present after the special operation, variations in detected operation states can be reduced, and as a result, the accuracy in detection of an occurrence of a fault, such as a leakage of refrigerant, can be improved.

Brief Description of Drawings [0012] [Fig. 1] Fig. 1 shows a configuration of a refrigerant circuit of a refrigeration cycle apparatus in Embodiment 1 of the present invention.

[Fig. 2] Fig. 2 shows a control configuration of the refrigeration cycle apparatus in Embodiment 1 of the present invention.

[Fig. 3] Fig. 3 is a flowchart illustrating fault determination processing in Embodiment 1 of the present invention.

[Fig. 4] Fig. 4 is a flowchart illustrating a flow of a refrigerant distribution 10 mandatory operation in Embodiment 1 of the present invention.

[Fig. 5] Fig. 5 shows examples of waveform of starting current at startups of the compressor in Embodiment 1 of the present invention.

[Fig. 6] Fig. 6 shows a transition of current at startups of the compressor in Embodiment 1 of the present invention.

[Fig. 7] Fig. 7 shows a configuration of a refrigerant circuit of a refrigeration cycle apparatus in Embodiment 2 of the present invention.

[Fig. 8] Fig. 8 is a flowchart illustrating fault determination processing of Embodiment 2 of the present invention.

[Fig. 9] Fig. 9 is a flowchart illustrating a flow of a refrigerant distribution 20 mandatory operation of Embodiment 2 of the present invention.

[Fig. 10] Fig. 10 shows a configuration of a refrigerant circuit of a refrigeration cycle apparatus in a modified example of Embodiment 2 of the present invention.

[Fig. 11] Fig. 11 shows a configuration of a refrigerant circuit of a refrigeration cycle apparatus of Embodiment 3 of the present invention.

[Fig. 12] Fig. 12 is a flowchart illustrating a flow of a refrigerant distribution mandatory operation in Embodiment 3 of the present invention.

[Fig. 13] Fig. 13 shows a schematic configuration of a remote monitoring system of Embodiment 4 of the present invention.

[Fig. 14] Fig. 14 shows a schematic configuration of a remote monitoring 30 system in a modified example of the present invention.

Description of Embodiments [0013]

Embodiments of a refrigeration cycle apparatus of the present invention will be described in details with reference to the drawings.

Embodiment 1

Fig. 1 shows a configuration of a refrigerant circuit of a refrigeration cycle apparatus 100 in Embodiment 1 of the present invention. The refrigeration cycle apparatus 100 of Embodiment 1 is a refrigerating apparatus that performs a vapor compression type refrigeration cycle operation. As shown in Fig. 1, the refrigeration cycle apparatus 100 includes a refrigerant circuit in which a compressor 11, a condenser 12, a receiver 15, a solenoid valve 16, a double-pipe heat exchanger 17, an expansion device 13, and an evaporator 14 are connected by pipes. In addition, the double-pipe heat exchanger 17 and the compressor 11 are connected with each other by a pipe 18, and the pipe 18 is provided with an expansion device 19. Note that the receiver 15, the solenoid valve 16, the double-pipe heat exchanger 17, the pipe 18, and the expansion device 19 may be omitted.

[0014]

The compressor 11 is formed of, for example, an inverter compressor capable of controlling a capacity, and sucks gas refrigerant and discharges the gas refrigerant after compressing the gas refrigerant into a high-temperature high-pressure state. The condenser 12 is, for example, a cross-fin type fin-and-tube heat exchanger formed of a heat-transfer tube and multiple fins, and exchanges heat between the high-temperature high-pressure refrigerant discharged from the compressor 11 and a heat medium, such as air and water, to condense the refrigerant. The expansion device 13 is formed of, for example, an expansion valve or a capillary tube, and expands the refrigerant condensed by the condenser 12 by reducing the pressure of the refrigerant. The evaporator 14 is, for example, a cross-fin type fin-and-tube heat exchanger, as with the condenser 12, and exchanges heat between the refrigerant expanded by the expansion device 13 and a heat medium, such as air and water, to evaporate the refrigerant.

[0015]

The receiver 15 stores surplus refrigerant. The solenoid valve 16 adjusts the flow rate of the refrigerant flowing into the double-pipe heat exchanger 17. The double-pipe heat exchanger 17 has a first flow path through which the refrigerant flowing from the receiver 15 flows and a second flow path through which the refrigerant flowing from the expansion device 19 flows, and is configured in such a manner that heat exchange can be performed between the first flow path and the second flow path. The pipe 18 is a pipe for injecting refrigerant into the compressor 11 via the first flow path of the double-pipe heat exchanger 17, the expansion device 19, and the second flow path of the double-pipe heat exchanger 17. The expansion device 19 is provided on the pipe 18, and is formed of, for example, an expansion valve for expanding refrigerant.

[0016]

Furthermore, the refrigeration cycle apparatus 100 is provided with detectors that detect information indicating operation states of the refrigeration cycle apparatus 100. The detectors include a suction temperature sensor 21, a discharge temperature sensor 22, and a current detector 23. The suction temperature sensor is provided on the suction side of the compressor 11 to detect the temperature of refrigerant to be sucked into the compressor 11. The discharge temperature sensor is provided on the discharge side of the compressor 11 to detect the temperature of discharged refrigerant. The current detector 23 is provided on a drive circuit of the compressor 11 to detect current applied to a motor of the compressor 11. The information indicating operation states includes the temperatures and the currents detected by the suction temperature sensor 21, the discharge temperature sensor 22, and the current detector 23. Note that, in the following explanation, information indicating an operation state is referred to as an operation state amount. In addition, an outside air temperature sensor 24 for detecting the outside air temperature is provided on a part of the refrigeration cycle apparatus 100, the part being installed on the outside of a room or the outside of the refrigeration cycle apparatus 100.

[0017]

Fig. 2 shows a control configuration ofthe refrigeration cycle apparatus 100. The refrigeration cycle apparatus 100 has a controller 30, a memory 40, a fault determiner 50, and a notifier 60. The controller 30 controls the rotation frequency of the compressor 11, the opening degrees of the expansion device 13, the expansion device 19, and the solenoid valve 16, and other parameters to perform operations of the refrigeration cycle apparatus 100. The memory 40 is formed of a large-capacity non-volatile memory or another device, and stores various programs and data used in controls of the controller 30. The memory 40 also stores operation state amounts, which are detected by the suction temperature sensor 21, the discharge temperature sensor 22, and the current detector 23, in association with the outside air temperatures that are detected by the outside air temperature sensor 24 when the operation state amounts are detected. Note that the memory 40 successively stores operation state amounts detected at startups in the past while associating with the outside air temperatures.

[0018]

The fault determiner 50 determines whether or not the refrigeration cycle apparatus 100 has a fault on the basis of the operation state amounts detected by the suction temperature sensor 21, the discharge temperature sensor 22, and the current detector 23. The notifier 60 notifies a user of the determination result made by the fault determiner 50 by displaying the result on a screen or with LED lights of the remote controller of the refrigeration cycle apparatus 100 or displaying the result on a monitor of a remote place, or by outputting the result as sound. Note that the controller 30, the fault determiner 50, and the notifier 60 each are formed of a function block implemented by a microcomputer or a digital signal processor (DSP) by executing programs, or formed of an electronic circuit, such as an application specific IC (ASIC).

[0019]

Next, operations of the refrigeration cycle apparatus 100 will be explained. In the refrigeration cycle apparatus 100, low-temperature low-pressure refrigerant in a gas state is compressed by the compressor 11 and is discharged as high-temperature high-pressure gas refrigerant. The high-temperature high-pressure gas refrigerant that has discharged from the compressor 11 flows into the condenser 12. The hightemperature high-pressure refrigerant that has flowed into the condenser 12 releases heat to outside air and is condensed to become high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed from the condenser 12 flows into the receiver 15 and is separated into liquid refrigerant and gas refrigerant. The liquid refrigerant that has flowed from the receiver 15 passes through the solenoid valve 16 and flows into the first flow path of the double-pipe heat exchanger 17. Then, the refrigerant that has flowed into the first flow path is cooled by heat exchange with the refrigerant that has flowed into the second flow path, thereby being subcooled.

[0020]

Some of the refrigerant that has flowed from the first flow path of the doublepipe heat exchanger 17 is branched and made to pass through the expansion device 19, whereby the pressure of the refrigerant is reduced and the temperature of the refrigerant is lowered. Then, the refrigerant, the temperature of which is lowered, flows into the second flow path of the double-pipe heat exchanger 17 to exchange heat with the refrigerant in the first flow path. The refrigerant that has flowed from the second flow path of the double-pipe heat exchanger 17 passes through the pipe 18 and flows into the compressor 11, and is used to lower the temperature of the gas refrigerant discharged from the compressor 11.

[0021]

The rest of the refrigerant that has flowed from the first flow path of the doublepipe heat exchanger 17 flows into the expansion device 13 and becomes lowtemperature low-pressure two-phase gas-liquid refrigerant after being expanded and decompressed. The two-phase gas-liquid refrigerant that has flowed from the expansion device 13 flows into the evaporator 14. The two-phase gas-liquid refrigerant that has flowed into the evaporator 14 evaporates after exchanging heat with air or water, and becomes low-temperature low-pressure gas refrigerant. The gas refrigerant that has flowed from the evaporator 14 is sucked into the compressor 11 and is compressed again.

[0022]

The types of the refrigerant that can be used in the refrigeration cycle apparatus 100 include a single component refrigerant, a near-azeotropic refrigerant mixture, and a non-azeotropic refrigerant mixture. Examples of the near-azeotropic refrigerant mixture include R410Aand R404A, which are HFC refrigerants. These near-azeotropic refrigerant mixtures have the same properties as a non-azeotropic refrigerant mixture, as well as a property of a working pressure that is 1.6 times the working pressure of R22. Examples of the non-azeotropic refrigerant mixture include R407C, which is an HFC (hydrofluorocarbon) refrigerant. This nonazeotropic refrigerant mixture is a mixture of refrigerants with different boiling points, and thus has a property in which the composition ratio of liquid-phase refrigerant and gas-phase refrigerant varies.

[0023]

Next, fault determination processing of the fault determiner 50 of the refrigeration cycle apparatus 100 will be explained. Fig. 3 is a flowchart illustrating fault determination processing of Embodiment 1. In this case, it is preferable that, when determining whether or not a fault is present in the refrigeration cycle apparatus 100, operation state amounts be detected under fixed conditions. One of the conditions is that the environmental temperatures, such as outside air temperatures and compartment temperatures, should be the same. In addition, it is known that an operation state amount (e.g., discharge temperature of compressor 11) to be detected varies depending on the distribution of the refrigerant amount at the startup. For this reason, first in the fault determination processing of Embodiment 1, a refrigerant distribution mandatory operation is performed by the controller 30 to make the distribution of the refrigerant amount uniform (S1). Fig. 4 is a flowchart illustrating a flow of the refrigerant distribution mandatory operation. Note that the refrigerant distribution mandatory operation corresponds to the special operation of the present invention.

[0024]

The refrigerant distribution mandatory operation of Embodiment 1 is performed when an instruction for operation stop of the refrigeration cycle apparatus 100 is made. When there is no instruction for operation stop (S11, NO), the process waits until an instruction for operation stop is made. When there is an instruction for operation stop (S11, YES), the solenoid valve 16 is fully closed (S12), and operation of the compressor 11 is continued (S13). Then, determination is made as to whether or not a predetermined period of time (e.g., 10 minutes) has elapsed (S14), and when the predetermined period of time has not elapsed (S14, NO), the operation of the compressor 11 is continued. Meanwhile, when the predetermined period of time has elapsed (S14, YES), the operation of the compressor 11 is stopped (S15), and then the process returns to the fault determination processing of Fig. 3. By performing the abovementioned refrigerant distribution mandatory operation, the refrigerant inside the refrigerant circuit of the refrigeration cycle apparatus 100 is gathered into the high pressure side (from the discharge side of the compressor 11 to the solenoid valve 16). Here, the predetermined period of time is the time required for gathering the refrigerant inside the refrigerant circuit of the refrigeration cycle apparatus 100 into the high pressure side, and is set in advance and stored in the memory 40. The time to be set varies depending on the size of the compressor 11, for example, when the compressor 11 is large, the time is set to 15 to 20 minutes, and when the compressor 11 is small, the time is set to 5 to 10 minutes. Note that, as the refrigerant distribution mandatory operation imposes a load on the compressor 11, it is preferable that the refrigerant distribution mandatory operation be finished within 30 minutes when the compressor 11 is large, and within 15 minutes when the compressor 11 is small. In addition, in S14, the operation of the compressor 11 is continued until the predetermined period of time elapses; however, the operation of the compressor 11 may be continued until, instead of elapsing time, the pressure of the refrigerant on the low pressure side (i.e., suction side) of the compressor 11 is decreased to a predetermined value. Specifically, the operation may be continued until the pressure of the refrigerant on the low pressure side of the compressor 11 is decreased to around 0.0 to 0.1 Mpa, for example.

[0025]

Referring back to Fig. 3, it is determined whether or not an instruction for operation start is made (S2), and when there is no instruction for operation start (S2, NO), the process waits. When an instruction for operation start is made (S2, YES), the outside air temperature is detected by the outside air temperature sensor 24 (S3). Then, a startup operation of the compressor 11 is performed (S4). At this moment, because the refrigerant distribution mandatory operation has been performed in S1, the load to be imposed on the compressor 11 becomes substantially the same at all times. In addition, in general, the operation pattern of the compressor 11 in a startup operation is the same for every model of the refrigeration cycle apparatus 100. Specifically, to attain a rotation frequency of 50 Hz within 10 seconds after a startup, the controller 30 controls the rotation frequency of the compressor 11 to increase the rotation frequency of the compressor 11 at a rate of 5 Hz/second.

[0026]

Then, while the compressor 11 is performing a startup operation, operation state amounts are detected (S5). Specifically, a suction temperature, a discharge temperature, and a current value of the compressor 11 are detected by the suction temperature sensor 21, the discharge temperature sensor 22, and the current detector 23, respectively. Then, it is determined whether or not past operation state amounts corresponding to the outside air temperature detected in S3 are stored in the memory 40 (S6). In this case, it is determined whether or not operation state amounts associated with the outside air temperature that is the same as the outside air temperature detected in S3 or that is within a predetermined temperature range (e.g., ±3 degrees C) are stored in the memory 40. Then, when no past operation state amount corresponding to the outside air temperature detected in S3 is stored in the memory 40 (S6, NO), the outside air temperature detected in S3 and the operation state amounts detected in S5 are stored in the memory 40 in association with each other (S7), and this processing is completed.

[0027]

Meanwhile, when past operation state amounts corresponding to the outside air temperature detected in S3 are stored in the memory 40 (S6, YES), the present operation state amounts detected in S5 are compared with the past operation state amounts stored in the memory 40 (S8), and it is determined whether or not a fault is present (S9).

[0028]

Determination of the presence or absence of a fault in S8 and S9 will be explained. The fault determiner 50 of Embodiment 1 determines, as faults of the refrigeration cycle apparatus 100, whether or not a leakage of refrigerant and a fault of the compressor 11 are present. First, a leakage of refrigerant will be explained. When the amount of refrigerant in the refrigerant circuit is reduced, a suction SH (degree of superheat) of the compressor 11 increases and the rising speed of discharge temperature at a startup increases. For this reason, the fault determiner 50 compares the discharge temperature detected at the present time by the discharge temperature sensor 22 with the discharge temperature, among the past operation state amounts, detected in the previous startup to obtain a difference Dt. Then, the fault determiner 50 determines that a leakage of refrigerant is present when the obtained difference Dt is equal to or greater than a predetermined threshold. [0029]

In addition, when the amount of refrigerant in the refrigerant circuit is reduced, the low pressure becomes lower than a normal condition. As the low pressure becomes lower, the high pressure (condensation pressure) also becomes lower. For this reason, the fault determiner 50 compares the low pressure based on the suction temperature or the high pressure based on the discharge temperature with the low pressure based on the suction temperature detected at the previous startup or the high pressure based on the discharge temperature detected at the previous startup, among the past operation state amounts stored in the memory 40, to obtain a difference Dp. Then, the fault determiner 50 determines that a leakage of refrigerant is present when the obtained difference Dp is equal to or greater than a threshold.

[0030]

Next, faults of the compressor 11 will be explained. When the total load torque required in a startup of the compressor 11 increases, the current value required in the startup increases. Thus, determination as to whether or not the total load torque at a startup is increased can be determined on the basis of current values. That is, on the basis of current values detected by the current detector 23, malfunctions (e.g., damage to a drive shaft) in the compressor 11 can be assumed. For this reason, the fault determiner 50 compares the maximum current value of the present time with the maximum current value detected at the previous startup, among the past operation state amounts stored in the memory 40, to obtain a difference Da. Then, the fault determiner 50 determines that a fault is present in the compressor 11 when the obtained difference Da is equal to or greater than a threshold. Note that the maximum current value at a startup is, for example, the maximum value observed within 10 seconds after the startup.

[0031]

In addition, as described above, in a startup operation of the compressor 11, the rotation frequency of the compressor 11 is controlled with the same operation pattern. For this reason, when the current peak (i.e., the maximum drive torque) at a startup occurs at a timing different from normal, it is considered that some sort of fault has occurred in the compressor 11. Thus, the fault determiner 50 compares the current peak position of the present time with the current peak positon detected at the previous startup, among the past operation state amounts stored in the memory 40, to obtain a difference Ds. Then, the fault determiner 50 determines that a fault is present in the compressor 11 when the obtained difference Ds is equal to or greater than a threshold (e.g., 10 seconds).

[0032]

Fig. 5 shows examples of waveform of starting current at startups of the compressor 11. In Fig. 5, the vertical axis indicates current value and the horizontal axis indicates time. In addition, in Fig. 5, C1 indicates a current waveform detected at the previous startup, and C2 and C3 indicate different examples of current waveform detected at the startup of the present time. By comparing C1 with C2, the maximum current value A2 of the present time is larger than the previous maximum current value A1. In addition, a difference Da between A1 and A2 is greater than a threshold Ra, and consequently, in this case, it is determined that a fault is present in the compressor 11. By comparing C1 with C3, the current peak position t2 of the present time lies after the current peak position t1 of the previous time. In addition, a difference Ds between t1 and t2 is greater than a threshold Rs, and consequently, in this case, too, it is determined that a fault is present in the compressor 11. Note that the thresholds used for comparison in the fault determiner 50 are set to any values, and are stored in the memory 40. In addition, the thresholds may be, in advance, obtained through, for example, experiments and may be stored in the memory 40. [0033]

Furthermore, the fault determiner 50 may obtain a difference Di between the current integrated value in a fixed period of time after the startup of the present time and the current integrated value in a fixed period of time after the previous startup detected at the previous startup, among the past operation state amounts stored in the memory 40, and may determine that a fault is present in the compressor 11 when the difference Di is equal to or greater than a predetermined threshold. In this case, the fixed period of time after a startup is, for example, three seconds after a startup. As described above, when a current integrated value is different under a condition where the compressor 11 is started with the same operation pattern, it is considered that the workload used in the startup is different. Consequently, in this case, it is considered that some sort of fault has occurred in the compressor 11.

[0034]

Determination as to whether or not a fault is present may be made not only by comparing the difference between an operation state amount of the present time and a previous operation state amount with a threshold, as described above, but also by comparing a trend of past operation state amounts with an operation state amount of the present time. Fig. 6 shows a transition of current at startups of the compressor 11. In Fig. 6, the vertical axis indicates the current (e.g., the maximum current value) and the horizontal axis indicates the number of times of startup. For example, as shown in Fig. 6, it is determined that a fault is present when the maximum current value detected at the present time (nth time) is significantly different from the inclination of the maximum current values of the past (up to n-1 th time).

[0035]

Then, in S9, when it is determined that a fault is not present (S9, NO), the outside air temperature detected in S3 and the operation state amounts detected in S5 are stored in the memory 40 in association with each other (S7), and this processing is completed. Meanwhile, when it is determined that a fault is present (S9, YES), the notifier 60 notifies a user of the occurrence of the fault (S10). Then, the outside air temperature detected in S3 and the operation state amounts detected in S5 are stored in the memory 40 in association with each other (S7), and this processing is completed.

[0036]

As described above, in Embodiment 1, by performing a refrigerant distribution mandatory operation, the amount of refrigerant is localized on the high-pressure side, and consequently, the suction condition at a startup of the compressor 11 becomes substantially constant. Thus, the internal condition at a startup of the compressor 11 becomes substantially constant, and as a result, variations in the operation state amounts detected for fault determination can be reduced. Consequently, comparison can be made using only the past operation state amounts stored in the memory 40 and the outside air temperatures as variables, and a fault determination with high accuracy can be performed, accordingly.

[0037]

In addition, because an operation state amount is detected at a startup at which the compressor 11 is controlled with a fixed operation pattern, variations in operation state amounts can be further reduced, and consequently, the accuracy of a fault determination can be further improved.

[0038]

Furthermore, by performing the fault determination processing by comparing the present operation state amount with a past operation state amount that has been detected at substantially the same outside air temperature as the outside air temperature at which the present operation state amount is detected, influences of outside air temperature on the operation state amounts can be reduced, and as a result, the accuracy of a fault determination can be improved. In addition, because it is determined that a fault is present when a difference between the present operation state amount and the past operation state amount is equal to or greater than a threshold, a case in which an error within an allowable range occurs is prevented from being determined as a fault.

[0039]

In addition, by using, as operation state amounts, temperatures, currents, and consumed powers detected by the suction temperature sensor 21, the discharge temperature sensor 22, and the current detector 23, the presence of various faults occurring in the refrigeration cycle apparatus 100 can be determined.

[0040]

Embodiment 2

Next, Embodiment 2 of the present invention will be explained. Fig. 7 shows a configuration of a refrigerant circuit of a refrigeration cycle apparatus 200 in Embodiment 2. The refrigeration cycle apparatus 200 of Embodiment 2 differs from the refrigeration cycle apparatus 100 of Embodiment 1 in that the refrigeration cycle apparatus 200 is an air-conditioning apparatus that performs a vapor compression type refrigeration cycle operation for cooling and heating inside the building. As shown in Fig. 7, the refrigeration cycle apparatus 200 includes a refrigerant circuit in which a compressor 111, an outdoor side heat exchanger 112, an expansion device 113, an indoor side heat exchanger 114, and a flow switching device 115 are connected by connection pipes. In addition, the compressor 111, the outdoor side heat exchanger 112, the expansion device 113, and the flow switching device 115 form an outdoor unit 210 that is disposed outdoors, and the indoor side heat exchanger 114 forms an indoor unit 220 that is disposed indoors. Furthermore, the refrigeration cycle apparatus 200 includes the suction temperature sensor 21, the discharge temperature sensor 22, the current detector 23, and the outside air temperature sensor 24 similarly to Embodiment 1.

[0041]

As with the compressor 11 of Embodiment 1, the compressor 111 is formed of an inverter compressor capable of controlling a capacity. The outdoor side heat exchanger 112 is, for example, a cross-fin type fin-and-tube heat exchanger, and acts as a condenser for refrigerant in a cooling operation and as an evaporator for refrigerant in a heating operation. The expansion device 113 is formed of, for example, an expansion valve or a capillary tube, and decompress and expands refrigerant. The indoor side heat exchanger 114 is, for example, a cross-fin type finand-tube heat exchanger, and acts as an evaporator for refrigerant in a cooling operation and as a condenser for refrigerant in a heating operation. The flow switching device 115 is formed of, for example, a four-way valve for switching the direction of the flow of refrigerant. In a cooling operation, the flow switching device 115 switches the flow path of refrigerant as illustrated with solid lines in Fig. 7 and, in a heating operation, switches the flow path of refrigerant as illustrated with broken lines in Fig. 7.

[0042]

Furthermore, the refrigeration cycle apparatus 200 of Embodiment 2 has the same control configuration as Embodiment 1 illustrated in Fig. 2. Note that the controller 30 of Embodiment 2 controls the rotation frequency of the compressor 111, the opening degree of the expansion device 113, and the switching of the flow path of the flow switching device 115.

[0043]

Next, operations of the refrigeration cycle apparatus 200 will be explained.

First, operations in a cooling operation will be explained. In a cooling operation, the flow path of refrigerant is switched, as illustrated with solid lines in Fig. 7, by the flow switching device 115. High-temperature high-pressure gas refrigerant that has compressed by and discharged from the compressor 111 passes through the flow switching device 115 and flows into the outdoor side heat exchanger 112. The hightemperature high-pressure refrigerant that has flowed into the outdoor side heat exchanger 112 releases heat to outside air and is condensed to become highpressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed from the outdoor side heat exchanger 112 flows into the expansion device 113 and is expanded and decompressed to become low-temperature low-pressure two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant that has flowed from the expansion device 113 flows into the indoor side heat exchanger 114. The two-phase gas-liquid refrigerant that has flowed into the indoor side heat exchanger 114 exchanges heat with indoor air, thereby evaporating and becoming low-temperature low-pressure gas refrigerant. The gas refrigerant that has flowed form the indoor side heat exchanger 114 is sucked into the compressor 11 and is compressed again. [0044]

Next, operations in a heating operation will be explained. In a heating operation, the flow path of refrigerant is switched, as illustrated with broken lines in Fig. 7, by the flow switching device 115. High-temperature high-pressure gas refrigerant that has compressed by and discharged from the compressor 111 passes through the flow switching device 115 and flows into the indoor side heat exchanger 114. The high-temperature high-pressure refrigerant that has flowed into the indoor side heat exchanger 114 releases heat to indoor air and is condensed to become high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed from the indoor side heat exchanger 114 flows into the expansion device 113 and is expanded and decompressed to become low-temperature low-pressure two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant that has flowed from the expansion device 113 flows into the outdoor side heat exchanger 112. The twophase gas-liquid refrigerant that has flowed into the outdoor side heat exchanger 112 exchanges heat with outdoor air, thereby evaporating and becoming low-temperature low-pressure gas refrigerant. The gas refrigerant that has flowed form the outdoor side heat exchanger 112 is sucked into the compressor 11 and is compressed again. [0045]

Next, fault determination processing of the refrigeration cycle apparatus 200 will be explained. Fig. 8 is a flowchart illustrating fault determination processing of Embodiment 2. In Fig. 8, the same processes as the fault determination processing of Embodiment 1 have been given the same reference signs as Fig. 3. First, in Embodiment 2, it is determined whether or not an instruction for operation start is made (S101). When there is no instruction for operation start (S101, NO), the process waits. Meanwhile, when an instruction for operation start is made (S101, YES), a refrigerant distribution mandatory operation is performed by the controller 30 (S102). Fig. 9 is a flowchart illustrating a flow of the refrigerant distribution mandatory operation of Embodiment 2. As described above, in Embodiment 2, the refrigerant distribution mandatory operation is performed when an instruction for operation start of the refrigeration cycle apparatus 200 is made.

[0046]

First, in the refrigerant distribution mandatory operation, the expansion device 113 is fully closed by the controller 30 (S21), and operation of the compressor 111 is started while the rotation frequency of the compressor 111 is fixed (S22). Then, determination is made as to whether or not a predetermined period of time (e.g., 10 minutes) has elapsed (S23), and when the predetermined period of time has not elapsed (S23, NO), the operation of the compressor 111 is continued. Meanwhile, when the predetermined period of time has elapsed (S23, YES), the operation of the compressor 111 is stopped (S24). At this moment, the refrigerant inside the refrigerant circuit of the refrigeration cycle apparatus 200 is gathered to the high pressure side (from the discharge side of the compressor 111 to the expansion device 113). The predetermined period of time in this case is set in advance depending on the size of the compressor 11 and other factors, as with the case of Embodiment 1. Note that the operation of the compressor 11 may be continued until, instead of elapsing the predetermined period of time, the pressure of the refrigerant on the low pressure side of the compressor 11 is decreased to a predetermined value (e.g., around 0.0 to 0.1 Mpa).

[0047]

Next, the expansion device 113 is fully opened (S25). Then, it is determined whether or not a predetermined period of time (e.g., three minutes) has elapsed (S26). When the predetermined period of time has elapsed (S26, YES), the process returns to the processing of Fig. 8. Then, in Fig. 8, the processes of S3 and the subsequent steps are performed as with the fault determination processing of Embodiment 1, and a fault determination of the refrigeration cycle apparatus 200 is performed.

[0048]

In Embodiment 2, in the refrigerant distribution mandatory operation, a high-low pressure difference in the refrigerant circuit is eliminated or reduced to a predetermined value or less by performing the processes of S25 and S26 after the refrigerant is gathered into a high-pressure side. Consequently, when the refrigeration cycle apparatus 200 is an air-conditioning apparatus and even when a heating operation and a cooling operation are switched from one to another, an adverse influence caused by a shock due to a high-low pressure difference in the refrigerant circuit on devices such as the flow switching device 115 can be reduced.

In addition, in this case, too, as with Embodiment 1, the distribution of the refrigerant amount at a startup can be made uniform, and variations in the operation state amounts detected for fault determination can be reduced, and as a result, a fault determination with high accuracy can be performed.

[0049]

Note that, in Embodiment 2, a configuration is made to wait (S25 and S26) until a predetermined period of time has elapsed to eliminate a high-low pressure difference in the refrigerant circuit, but is not limited to this manner. For example, instead of setting a predetermined period of time, a unit for detecting a high-low pressure difference may be provided, and, when the detected high-low pressure difference is reduced to a set value, the process may be shifted to the process of S3. [0050]

Furthermore, the configuration of the refrigerant circuit of Embodiment 2 is not limited to the configuration shown in Fig. 7. Fig. 10 shows a configuration of a refrigerant circuit of a refrigeration cycle apparatus 200A in a modified example of Embodiment 2. For example, as shown in Fig. 10, an accumulator 118 for storing surplus refrigerant may be provided on a suction side of a compressor 111. In this case, too, a fault in the refrigeration cycle apparatus 200A is determined by performing the refrigerant distribution mandatory operation (Fig. 9) and the fault determination processing (Fig. 8) as with the case of Embodiment 2. In addition, in this case, by performing the refrigerant distribution mandatory operation shown in Fig. 9, the refrigerant including the surplus refrigerant in the accumulator 118 is gathered into a high-pressure side. Furthermore, a configuration is made in such a manner that, in the refrigerant distribution mandatory operation, an expansion device 113 is fully closed in S21 and the compressor 111 is driven for a predetermined period of time; however, the configuration is not limited to this manner, and the expansion device 113 may be controlled to increase a suction SH of the compressor 11. In this case, too, a suction condition at a startup of the compressor 111 can be kept constant.

[0051]

Embodiment 3

Next, Embodiment 3 of the present invention will be explained. Fig. 11 shows a configuration of a refrigerant circuit of a refrigeration cycle apparatus 300 of Embodiment 3. The refrigeration cycle apparatus 300 of Embodiment 3 differs from the refrigeration cycle apparatus 200 of Embodiment 2 in that a receiver 117 is provided between an outdoor side heat exchanger 112 and an indoor side heat exchanger 114. In Fig. 11, the same components as Embodiment 2 have been given the same reference signs as Fig. 7. The refrigerant circuit of the refrigeration cycle apparatus 300 is formed by connecting, by connection pipes, a compressor 111, the outdoor side heat exchanger 112, a first expansion device 116a, the receiver 117, a second expansion device 116b, the indoor side heat exchanger 114, and a flow switching device 115. In addition, the compressor 111, the outdoor side heat exchanger 112, the flow switching device 115, the first expansion device 116a, the second expansion device 116b, and the receiver 117 form an outdoor unit 310, and the indoor side heat exchanger 114 forms an indoor unit 320.

[0052]

The receiver 117, in the refrigerant circuit, is located between the first expansion device 116a and the second expansion device 116b, and stores surplus refrigerant. Furthermore, the refrigeration cycle apparatus 300 includes the suction temperature sensor 21, the discharge temperature sensor 22, the current detector 23, and the outside air temperature sensor 24 similarly to Embodiment 1. In addition, the refrigeration cycle apparatus 300 has the same control configuration as Embodiment 1 illustrated in Fig. 2. Note that the controller 30 of Embodiment 3 controls the rotation frequency of the compressor 111, the opening degrees of the first expansion device 116a and the second expansion device 116b, and the switching of the flow switching device 115.

[0053]

Next, fault determination processing in the refrigeration cycle apparatus 300 will be explained. The fault determination processing of Embodiment 3 differs from that of Embodiment 2 in the flow of the refrigerant distribution mandatory operation in S102 of Fig. 8. The other processes of the fault determination processing are the same as the fault determination processing of Embodiment 2 shown in Fig. 8. Fig.

is a flowchart illustrating a flow of the refrigerant distribution mandatory operation in Embodiment 3. In Fig. 12, the same processes as the refrigerant distribution mandatory operation of Embodiment 2 have been given the same reference signs as Fig. 9.

[0054]

First, in the refrigerant distribution mandatory operation of Embodiment 3, an upstream side expansion device is controlled and a downstream side expansion device is fully closed (S31). Here, in a cooling operation, the first expansion device 116a is the upstream side expansion device, and the second expansion device 116b is the downstream side expansion device. In a heating operation, the first expansion device 116a is the downstream side expansion device, and the second expansion device 116b is the upstream side expansion device. In addition, the upstream side expansion device is controlled by the controller 30 to increase a suction SH of the compressor 111.

[0055]

Then, operation of the compressor 111 is started while the rotation frequency of the compressor 111 is fixed (S22). Then, determination is made as to whether or not a predetermined period of time (e.g., 10 minutes) has elapsed (S23), and when the predetermined period of time has not elapsed (S23, NO), the operation of the compressor 111 is continued. Meanwhile, when the predetermined period of time has elapsed (S23, YES), the operation of the compressor 111 is stopped (S24). Consequently, the refrigerant inside the refrigerant circuit of the refrigeration cycle apparatus 300, including the surplus refrigerant in the receiver 117, is gathered to the devices and pipes on the high pressure side. The predetermined period of time in this case is set in advance depending on the size of the compressor 11 and other factors, as with the case of Embodiment 1. Note that the operation of the compressor 11 may be continued until, instead of elapsing the predetermined period of time, the pressure of the refrigerant on the low pressure side of the compressor 11 is decreased to a predetermined value (e.g., around 0.0 to 0.1 Mpa).

[0056]

Next, the upstream side expansion device and the downstream side expansion device are fully opened (S35). Then, it is determined whether or not a predetermined period of time (e.g., three minutes) has elapsed (S26). When the predetermined period of time has elapsed (S26, YES), the process returns to the fault determination processing. In the fault determination processing, the same processing as Embodiment 2 is performed to perform a fault determination of the refrigeration cycle apparatus 300.

[0057]

As described above, by performing the refrigerant distribution mandatory operation, a fault determination with high accuracy can be performed also in the refrigeration cycle apparatus 300 equipped with the receiver 117, as with Embodiment 1 and Embodiment 2.

[0058]

Embodiment 4

Next, Embodiment 4 of the present invention will be explained. Embodiment 4 differs from Embodiment 1 in that fault determination processing is performed in a remote monitoring apparatus 500 provided at a place away from a refrigeration cycle apparatus 100A. Fig. 13 shows a schematic configuration of a remote monitoring system 400 of Embodiment 4. The remote monitoring system 400 is formed of a refrigeration cycle apparatus 100A and a remote monitoring apparatus 500. As shown in Fig. 13, in Embodiment 4, the remote monitoring apparatus 500 has a controller 30, a memory 40, a fault determiner 50, and a notifier 60. In addition, the refrigeration cycle apparatus 100A includes the same refrigerant circuit configuration as Embodiment 1.

[0059]

The refrigeration cycle apparatus 100Aand the remote monitoring apparatus 500 have a communicator 70a and a communicator 70b, respectively. The communicators 70a and 70b communicate with each other wirelessly or through cable. The remote monitoring apparatus 500 is formed of a computer, and performs remote monitoring and centralized management of controls of the refrigeration cycle apparatus 100A via the communicator 70b.

[0060]

In Embodiment 4, operation state amounts detected in the refrigeration cycle apparatus 100A are transmitted to the remote monitoring apparatus 500 via the communicator 70a, and control of a refrigerant distribution mandatory operation and fault determination processing are performed in the remote monitoring apparatus 500. In this case, the flows of a refrigerant distribution mandatory operation and fault determination processing are the same as the flows of a refrigerant distribution mandatory operation and fault determination processing of Embodiment 1 illustrated in Fig. 3 and Fig. 4. With such a configuration, the same effects as Embodiment 1 can be obtained, and faults of the refrigeration cycle apparatus 100Acan be constantly monitored remotely. In addition, by installing a large-capacity memory 40 on the remote monitoring apparatus 500, cost can be reduced compared with a case where a large-capacity memory 40 is installed on the refrigeration cycle apparatus 100A.

[0061]

Although the above are explanations of the embodiments of the present invention, the present invention is not limited to the configurations of the abovementioned embodiments, and various modifications or combinations can be made within the scope of the technical ideas. For example, the refrigeration cycle apparatus 100 of Embodiment 1 includes one compressor 11, one condenser 12 and one evaporator 14, as shown in Fig. 1; however, the present invention does not specifically limit the number of these components. For example, two or more compressors 11, condensers 12, and evaporators 14 may be provided. Similarly, in Embodiment 2, the numbers of the outdoor units 210 and the indoor units 220 are not limited, and various combinations of the numbers can be made. Fig. 14 shows a schematic configuration of a remote monitoring system 400A in a modified example. For example, as shown in Fig. 14, a plurality of indoor units 220a to 220c may be connected to one outdoor unit 210, and these units may be monitored and controlled by a remote monitoring apparatus 500.

[0062]

In addition, in the abovementioned embodiments, fault determination processing is performed on the basis of the operation state amounts that have been detected in the past and stored in the memory 40, but is not limited to the embodiments. For example, the refrigeration cycle apparatus 100 may set, in advance, a reference current waveform in a normal condition and compare a current waveform at the present time with the reference current waveform to determine whether a fault is present in the compressor 11 or whether the condition of suction refrigerant of the compressor 11 is stable. In addition, in a case where the refrigeration cycle apparatus 200 is provided with a plurality of outdoor units 210 and one or more indoor units 220 are connected to each outdoor unit 210, past operation state amounts may be shared among the plurality of outdoor units 210, and determination of a fault may be performed by comparing the operation state amounts of one outdoor unit 210 with operation state amounts of another outdoor unit 210, when the operation conditions are matched with each other, [0063]

Furthermore, the detected operation state amounts are not limited to the examples of the abovementioned embodiments, and various state amounts in a refrigerant circuit can be detected to perform determination of a fault. For example, a consumed power detector may be provided on a compressor 11, and it may be determined that some sort of fault has occurred in the compressor 11 when a difference between the consumed power of the compressor 11 and the consumed power of the compressor 11 at the previous startup is equal to or greater than a predetermined threshold.

Reference Signs List [0064]

11,111 compressor 12 condenser 13,113 expansion device 14 evaporator 15,117 receiver 16 solenoid valve 17 double-pipe heat exchanger 18 pipe 19 expansion device 21 suction temperature sensor 22 discharge temperature sensor 23 current detector 24 outside air temperature sensor 30 controller 40 memory 50 fault determiner 60 notifier 70a communicator 70b communicator 100, 100A, 200, 200A, 300 refrigeration cycle apparatus 112 outdoor side heat exchanger 114 indoor side heat exchanger 115 flow switching device 116a first expansion device 116b second expansion device 118 accumulator 210,310 outdoor unit 220,220a, 220b, 220c, 320 indoor unit 400, 400A remote monitoring system 500 remote monitoring apparatus

Claims

CLAIMS [Claim 1]

A refrigeration cycle apparatus comprising:

a refrigerant circuit including a compressor, a condenser, an expansion device, and an evaporator;

a controller configured to control the refrigerant circuit; and a fault determiner configured to determine whether the refrigerant circuit has a fault, the controller being configured to perform a special operation driving and stopping the compressor, the special operation stopping the compressor in response to an event including one of elapse of a predetermined time, and decreasing, to a predetermined value, a pressure of refrigerant at a suction side of the compressor, the fault determiner being configured to determine whether the refrigerant circuit has a fault after the special operation.
[Claim 2]

The refrigeration cycle apparatus of claim 1, further comprising a detector configured to detect information including a suction temperature of refrigerant of the compressor, a discharge temperature of refrigerant of the compressor, a current applied to the compressor, or a consumed power of the compressor, wherein the fault determiner is configured to determine whether the refrigerant circuit has a fault on a basis of the information detected by the detector after the special operation.
[Claim 3]

The refrigeration cycle apparatus of claim 1 or 2, wherein the special operation is configured to gather refrigerant in the refrigerant circuit into a place between a discharge side of the compressor and the expansion device.
[Claim 4]

The refrigeration cycle apparatus of claim 2 or 3, wherein the fault determiner is configured to determine whether the refrigerant circuit has a fault on a basis of the information detected by the detector at a startup of the compressor after the special operation.
[Claim 5]

The refrigeration cycle apparatus of claim 4, further comprising: an outside air temperature sensor configured to detect an outside air temperature; and a memory configured to store the information and the outside air temperature in association with each other, the outside air temperature being detected by the outside air temperature sensor when the information is detected, wherein the fault determiner is configured to determine whether the refrigerant circuit has a fault by comparing past information that is among the information stored in the memory and corresponds to the outside air temperature detected by the outside air temperature sensor, with the information detected at the startup of the compressor after the special operation.
[Claim 6]

The refrigeration cycle apparatus of claim 5, wherein the fault determiner is configured to obtain a difference between the past information corresponding to the outside air temperature and the information detected by the detector at the startup of the compressor after the special operation and is configured to determine that the refrigerant circuit has a fault when the difference is equal to or greater than a predetermined threshold.
[Claim 7]

The refrigeration cycle apparatus of any one of claims 1 to 6, wherein the controller is configured to perform the special operation in such a manner that a suction condition of refrigerant at a startup of the compressor becomes substantially constant.
[Claim 8]

The refrigeration cycle apparatus of any one of claims 1 to 7, wherein the refrigerant circuit further includes a solenoid valve disposed between the condenser and the expansion device, and the controller is configured to control the refrigerant circuit to gather refrigerant into a place between the suction side of the compressor and the solenoid valve in the special operation.
[Claim 9]

The refrigeration cycle apparatus of claim 8, wherein the controller is configured to fully close the solenoid valve and operate the compressor for the predetermined time in the special operation.
[Claim 10]

The refrigeration cycle apparatus of any one of claims 1 to 7, wherein the controller is configured to control the refrigerant circuit to decrease a high-low pressure difference in the refrigerant circuit after the special operation.
[Claim 11]

The refrigeration cycle apparatus of claim 10, wherein the controller is configured to fully close the expansion device, operate the compressor for the predetermined time, then stop the compressor, and fully open the expansion device for a predetermined time in the special operation.
[Claim 12]

The refrigeration cycle apparatus of claim 10, wherein the refrigerant circuit further includes a receiver disposed between the evaporator and the condenser, the expansion device includes an upstream side expansion device disposed at an upstream of the receiver and a downstream side expansion device disposed at a downstream of the receiver, and the controller is configured to fully close the downstream side expansion device, operate the compressor for the predetermined time and control the upstream side expansion device, then stop the compressor, and fully open the upstream side expansion device and the downstream side expansion device for a predetermined time in the special operation.
[Claim 13]

The refrigeration cycle apparatus of any one of claims 4 to 12, wherein the controller is configured to control a rotation frequency of the compressor with a fixed operation pattern at the startup of the compressor.
[Claim 14]

A remote monitoring system comprising: a refrigeration cycle apparatus; and a remote monitoring apparatus communicating with the refrigeration cycle apparatus, the refrigeration cycle apparatus including a refrigerant circuit including a compressor, a condenser, an expansion device, and an evaporator, and a communicator configured to communicate with the remote monitoring apparatus, and the remote monitoring apparatus including a communicator configured to communicate with the refrigeration cycle apparatus, a controller configured to control the refrigerant circuit via the communicator, and a fault determiner configured to determine whether the refrigerant circuit has a fault, the controller being configured to perform a special operation driving and stopping the compressor, the special operation stopping the compressor in response to an event including one of elapse of a predetermined time, and decreasing, to a predetermined value, a pressure of refrigerant at a suction side of the compressor, the fault determiner being configured to determine whether the refrigerant circuit has a fault after the special operation.
[Claim 15]

A remote monitoring apparatus comprising:

a communicator configured to communicate with a refrigeration cycle apparatus;

a controller configured to control a refrigerant circuit for the refrigeration cycle apparatus via the communicator; and a fault determiner configured to determine whether the refrigerant circuit has a fault, the controller being configured to perform a special operation driving and stopping a compressor, the special operation stopping the compressor in response to an event including one of elapse of a predetermined time, and decreasing, to a predetermined value, a pressure of refrigerant at a suction side of the compressor, the fault determiner being configured to determine whether the refrigerant circuit has a fault after the special operation.
[Claim 16]

A method of determining whether a fault is present in a refrigerant circuit including a compressor, a condenser, an expansion device, and an evaporator, the method comprising:

performing a special operation driving and stopping the compressor, the special operation stopping the compressor in response to an event including one of elapse of a predetermined time, and decreasing, to a predetermined value, a pressure of refrigerant at a suction side of the compressor; and determining whether the refrigerant circuit has a fault after the special operation.