WO2021009881A1 - Refrigeration cycle system - Google Patents

Abstract

This refrigeration cycle system comprises: a detection means for detecting a relevant physical quantity, which is a physical quantity relating to the state of a refrigerant circuit; and a control means for executing a circuit state determination mode after starting a compressor and before starting a normal operation mode in which the refrigeration cycle operation by the refrigerant circuit is performed. The control means switches from the circuit state determination mode to the normal operation mode if a first comparison value CQ1 obtained by comparing a first detection value PQ1, which is the value of the relevant physical quantity at the point in time at which a first time has elapsed from the start time of the circuit state determination mode, and a second detection value PQ2, which is the value of the relevant physical quantity at the point in time at which a second time longer than the first time has elapsed from the start time, is smaller than a normal determination value A. Otherwise, the circuit state determination mode is continued.

Description

Refrigeration cycle system

The present invention relates to a refrigeration cycle system.

In Patent Document 1 below, as a technique for determining an abnormality in the refrigerant circuit of a heat pump water heater, a current value detecting means for detecting the current value flowing through the compressor is provided, and the current value is provided within a predetermined time after the compressor is started. A technique for stopping the operation of a compressor when the current value detected by the detecting means exceeds a predetermined value is disclosed.

Japanese Patent Application Laid-Open No. 2010-071603

In the above-mentioned conventional system, even if the refrigerant circuit is normal, it cannot be determined that the refrigerant circuit is normal until the predetermined time elapses, so that the normal operation cannot be started. Then, the detector has variations in characteristics due to individual differences within the normal range. Therefore, in the conventional system described above, there is some error in the measured current value. Further, the elements of the refrigerant circuit (for example, the decompression device) also have variations in characteristics due to individual differences within the normal range. In the above-mentioned conventional system, in order to prevent erroneous determination due to variation due to individual differences within the normal range, it is necessary to set the predetermined time to a long time. As a result, even if the refrigerant circuit is normal, it takes a long time from the start of the compressor to the start of the normal operation, which causes a problem of increasing the power consumption.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a refrigeration cycle system which is advantageous in shortening the time from the start of the compressor to the start of the normal operation. And.

The refrigeration cycle system of the present invention uses a compressor that compresses the refrigerant, a cooler that cools the refrigerant compressed by the compressor, a decompression device that decompresses the refrigerant that has passed through the cooler, and a refrigerant that has passed through the decompression device. A refrigerant circuit having an evaporator to evaporate, a detecting means for detecting a related physical quantity which is a physical quantity related to the state of the refrigerant circuit, and after starting the compressor, before starting the normal operation mode in which the refrigerating cycle operation is performed by the refrigerant circuit. A control means for executing the circuit state determination mode is provided, and the control means includes a first detection value which is a value of a related physical quantity when the first time elapses from the start time of the circuit state determination mode, and a first detection value which is a value from the start time. If the first comparison value obtained by comparing with the second detection value, which is the value of the related physical quantity when the second time longer than one hour elapses, is smaller than the normal judgment value, the circuit state judgment mode Is switched to the normal operation mode, and if not, the circuit state determination mode is continued.

According to the present invention, it is possible to provide a refrigeration cycle system that is advantageous in shortening the time from the start of the compressor to the start of the normal operation.

It is a figure which shows the refrigeration cycle system by Embodiment 1. FIG. It is a flowchart which shows an example of the process which a control part executes in a circuit state determination mode. It is a figure which shows the example of the time-dependent change of the related physical quantity after the start of a compressor. It is a figure which shows the example of the time-dependent change of the related physical quantity after the start of a compressor when the evaporator inlet temperature is used as a related physical quantity.

Hereinafter, embodiments will be described with reference to the drawings. The common or corresponding elements in the drawings are designated by the same reference numerals to simplify or omit the common description.

Embodiment 1.
FIG. 1 is a diagram showing a refrigeration cycle system according to the first embodiment. As shown in FIG. 1, the refrigeration cycle system 1 includes a refrigerant circuit 2, a measuring unit 7, and a control unit 8. The refrigerant circuit 2 includes a compressor 3 that compresses the refrigerant, a cooler 4 that cools the high-pressure refrigerant compressed by the compressor 3, a decompression device 5 that decompresses the high-pressure refrigerant that has passed through the cooler 4, and a decompression device 5. It is provided with an evaporator 6 that evaporates the low-pressure refrigerant decompressed by. The compressor 3, the cooler 4, the decompression device 5, and the evaporator 6 are connected via a refrigerant pipe to form an annular circuit. The low-pressure refrigerant gas flowing out of the evaporator 6 is sucked into the compressor 3 and circulates in the refrigerant circuit 2 again. The refrigerant circuit 2 is operated by electric power.

The refrigerant sealed in the refrigerant circuit 2 is not particularly limited, but may be, for example, carbon dioxide, ammonia, propane, isobutane, fluorocarbons such as HFC, HFO-1123, or HFO-1234yf.

The cooler 4 corresponds to a heat exchanger that exchanges heat between the high-pressure refrigerant discharged from the compressor 3 and the first fluid having a temperature lower than that of the high-pressure refrigerant. In the cooler 4, the temperature of the first fluid rises by being heated by the high-pressure refrigerant. The first fluid may be, for example, a liquid such as water or other liquid heat medium, or a gas such as outdoor or indoor air. The refrigeration cycle system 1 may include a first fluid actuator (not shown), such as a pump or blower, for flowing the first fluid to the cooler 4.

The decompression device 5 expands the high-pressure refrigerant into a low-pressure refrigerant. The pressure reducing device 5 may be an expansion valve whose opening degree of the refrigerant passage can be adjusted. The low-pressure refrigerant that has passed through the vacuum distillation device 5 is in a gas-liquid two-phase state.

The evaporator 6 corresponds to a heat exchanger that exchanges heat between a low-pressure refrigerant decompressed by the decompression device 5 and a second fluid having a temperature higher than that of the low-pressure refrigerant. The refrigerant in the evaporator 6 evaporates by absorbing the heat of the second fluid. The second fluid may be, for example, a gas such as outdoor or indoor air, or a liquid such as water or other liquid heat medium. The refrigeration cycle system 1 may include a second fluid actuator (not shown), such as a blower or pump, for flowing the second fluid to the evaporator 6.

The refrigeration cycle system 1 may be used for the purpose of heating the first fluid by the cooler 4, or may be used for the purpose of cooling the second fluid by the evaporator 6. For example, the refrigeration cycle system 1 may be used in at least one of a heat pump hot water supply system, a heat pump heating system, and an air conditioning system.

The physical quantity related to the state of the refrigerant circuit 2 is hereinafter referred to as "related physical quantity". The measuring unit 7 has a detector that detects a related physical quantity. The detector corresponds to a detection means for detecting a related physical quantity. The measuring unit 7 can measure the value of the related physical quantity by using the detector. The measuring unit 7 detects at least one kind of related physical quantity. The measuring unit 7 in the present embodiment detects the compressor current, which is the current flowing through the electric motor included in the compressor 3, as a related physical quantity. The compressor current correlates with the drive load of the compressor 3. The higher the pressure on the high pressure side of the refrigerant circuit 2, the higher the drive load of the compressor 3 and the higher the compressor current. Therefore, it can be said that the compressor current is a kind of related physical quantity.

The measuring unit 7 may detect only the current supplied to the compressor 3 as the compressor current, or the current supplied to the compressor 3 and other devices (for example, a first fluid actuator and a second fluid actuator). The current including the current supplied to the compressor may be detected as the compressor current. Since the current supplied to the other device is smaller than the current supplied to the compressor 3, it can be substantially ignored. In the case of alternating current, the measuring unit 7 may detect the effective value of the current as the compressor current.

The control unit 8 corresponds to a control means for controlling the operation of the refrigeration cycle system 1. Each actuator and each sensor included in the refrigeration cycle system 1 are electrically connected to the control unit 8. The control unit 8 has a timer function for managing the time. The control unit 8 may be able to communicate with a user interface device (not shown).

Each function of the control unit 8 may be realized by a processing circuit. The processing circuit of the control unit 8 may include at least one processor 8a and at least one memory 8b. At least one processor 8a may realize each function of the control unit 8 by reading and executing a program stored in at least one memory 8b. Each processing circuit of the control unit 8 may include at least one dedicated hardware. The configuration is not limited to the configuration in which the operation is controlled by a single control unit 8 as in the illustrated example, and the operation may be controlled by the cooperation of a plurality of control devices.

The control unit 8 controls the operation of the compressor 3 and the decompression device 5. The control unit 8 may be controlled so that the operating speed of the compressor 3 is variable, for example, by inverter control. The control unit 8 may adjust the opening degree of the decompression device 5. Further, the control unit 8 may be controlled so that the operating speed of at least one of the first fluid actuator and the second fluid actuator becomes variable by, for example, inverter control.

The control unit 8 can execute a normal operation mode in which the refrigerating cycle operation is performed by the refrigerant circuit 2. In the normal operation mode, the following may be performed. The control unit 8 may control the operating speed of the compressor 3 according to the target heating capacity or cooling capacity. The control unit 8 may adjust the opening degree of the vacuum reducing device 5 according to the temperature or pressure of the refrigerant discharged from the compressor 3. The control unit 8 may control the operating speed of the first fluid actuator according to at least one of the temperature of the first fluid flowing into the cooler 4 and the temperature of the first fluid flowing out of the cooler 4. .. The control unit 8 may control the operating speed of the second fluid actuator according to at least one of the temperature of the second fluid flowing into the evaporator 6 and the temperature of the second fluid flowing out of the evaporator 6. ..

The control unit 8 executes a circuit state determination mode for determining the state of the refrigerant circuit 2 after the compressor 3 is started and before the normal operation mode is started. The start time point of the circuit state determination mode is hereinafter referred to as "start time point". The control unit 8 may set the time when the compressor 3 is started as the start time. In the circuit state determination mode, it is desirable that the control unit 8 keeps the operating speed of the compressor 3 at a predetermined constant speed. Thereby, the state of the refrigerant circuit 2 can be determined more accurately. Further, in the circuit state determination mode, it is desirable that the control unit 8 keeps the operating speed of the first fluid actuator at a predetermined constant speed or stops the first fluid actuator, and keeps the operating speed of the second fluid actuator at a predetermined constant speed. It is desirable to keep the speed or stop the second fluid actuator. By doing so, the state of the refrigerant circuit 2 can be determined more accurately.

FIG. 2 is a flowchart showing an example of processing executed by the control unit 8 in the circuit state determination mode. FIG. 3 is a diagram showing an example of changes in the related physical quantities with time after the start of the compressor 3. In the present embodiment, the time-dependent change of the related physical quantity shown in FIG. 3 corresponds to the time-dependent change of the compressor current. In FIG. 3, the time t0 corresponds to the start time.

In the present embodiment, the control unit 8 has a first detection value PQ1 which is a value of the compressor current when a predetermined first time has elapsed from the start time, and a predetermined first detection value longer than the first time from the start time. If the first comparison value CQ1 obtained by comparing with the second detection value PQ2, which is the value of the compressor current when two hours have passed, is smaller than the predetermined normal judgment value A, the circuit state is determined. Switch from mode to normal operation mode, otherwise continue circuit state determination mode. In FIG. 3, the time from time t0 to time t1 corresponds to the first time, and the time from time t0 to time t2 corresponds to the second time.

The first comparison value CQ1 may be the difference between the first detection value PQ1 and the second detection value PQ2. In this case, the control unit 8 may calculate the first comparison value CQ1 by, for example, the following equation.
CQ1 = | PQ2-PQ1 | ... (1)

Alternatively, the first comparison value CQ1 may be the rate of increase / decrease between the first detection value PQ1 and the second detection value PQ2. In this case, the control unit 8 may calculate the first comparison value CQ1 by, for example, the following equation.
CQ1 = | PQ2 / PQ1-1 | ... (2)

As shown in FIG. 3, after the compressor 3 is started, the compressor current gradually increases. When the element of the refrigerant circuit 2 (for example, the vacuum distillation device 5) is normal, the operation of the element keeps the inside of the refrigerant circuit 2 at an appropriate pressure. As a result, around time t1 when the first time elapses from the start time, the degree of increase in the compressor current slows down, and the compressor current converges within a substantially constant range. In such a case, since the second detection value PQ2 is close to the first detection value PQ1, the first comparison value CQ1 is smaller than the normal determination value A. Therefore, if the first comparison value CQ1 is smaller than the normal determination value A, it can be determined that the refrigerant circuit 2 is clearly normal, and there is no problem even if the normal operation mode is started.

While the circuit state judgment mode is being executed, the target heating capacity or cooling capacity cannot be obtained, the first fluid cannot be sufficiently heated, or the second fluid cannot be sufficiently cooled. Therefore, it is not preferable that the time to shift from the circuit state determination mode to the normal operation mode is delayed.

In the present embodiment, by comparing the first comparison value CQ1 with the normal determination value A, if the refrigerant circuit 2 is clearly normal, it can be determined at an early stage. Therefore, there is an advantage that the normal operation mode can be shifted at an early stage.

On the other hand, if there is an abnormality in the elements of the refrigerant circuit 2, the pressure inside the refrigerant circuit 2 will not be appropriate. For example, when there is an abnormality that the refrigerant flow path of the decompression device 5 is blocked, the pressure on the downstream side of the compressor 3 rises abnormally. As a result, the drive load of the compressor 3 becomes excessive, the degree of increase in the compressor current does not slow down even after the first time has passed from the start time, and the compressor current does not converge within a substantially constant range. In such a case, since the difference between the second detection value PQ2 and the first detection value PQ1 is large, the first comparison value CQ1 is larger than the normal determination value A. In the present embodiment, when the first comparison value CQ1 is equal to or higher than the normal determination value A, the circuit state determination mode is continued. Therefore, it is possible to reliably prevent the normal operation mode from being started when it cannot be confirmed that the refrigerant circuit 2 is normal.

In general, detectors that detect related physical quantities such as compressor current have variations in characteristics due to individual differences. Therefore, there is some error in the value of the related physical quantity measured by the measuring unit 7. If the measured value of the related physical quantity itself is compared with the judgment value, there is a possibility of erroneous judgment due to the influence of the error of the measured value due to the variation of the detector. On the other hand, in the present embodiment, the error included in the first detection value PQ1 and the error included in the second detection value PQ2 cancel each other out, so that the first comparison value CQ1 is affected by the error. Hateful. Therefore, in the present embodiment, by comparing the first comparison value CQ1 with the normal determination value A, the influence of the error can be surely reduced, so that the erroneous determination can be surely prevented.

In the following description, with respect to the element of the refrigerant circuit 2, the individual having the statistical median value of the characteristic among the plurality of normal products inspected in the characteristic inspection of the element alone is referred to as "central product". For example, the central product of the decompression device 5 corresponds to an individual whose flow rate characteristic is a statistical median among a plurality of normal products. In addition, among a plurality of normal products, an individual having a lower limit of the statistical distribution of the above characteristics is referred to as a "lower limit product". For example, the lower limit product of the decompression device 5 is an individual whose refrigerant flow rate is lower under the same setting than the central product of the decompression device 5. The lower limit product is included in the normal product. Therefore, the refrigerant circuit 2 in which the lower limit product is used is included in the normal range.

FIG. 3 shows a graph of related physical quantities when the central product is used and a graph of related physical quantities when the lower limit product is used. In the case of the lower limit product, the flow rate of the refrigerant passing through the decompression device 5 is lower than that in the case of the central product, so that the pressure on the downstream side of the compressor 3 is higher than that in the case of the central product. As a result, the compressor current in the case of the lower limit product is higher than the compressor current in the case of the central product. Further, in the case of the lower limit product, the time at which the increase in the compressor current slows down is later than the time in which the increase in the compressor current slows down in the case of the central product. As a result, in the case of the lower limit product, the refrigerant circuit 2 is normal, but since the difference between the second detection value PQ2 and the first detection value PQ1 is large, the first comparison value CQ1 is compared with the normal determination value A. growing.

In the present embodiment, the respective values of the first hour, the second hour, and the normal determination value A are defined as values that can determine that the refrigerant circuit 2 is normal when the central product is used. There is. For example, the first time is set so that when the central product is used, the related physical quantity converges within a substantially constant range. In the present embodiment, when the refrigerant circuit 2 is clearly normal as in the case where the central product is used, it can be determined earlier, so that the normal operation can be performed earlier. You can switch to mode.

If the circuit state determination mode is continued even after the second time has elapsed, that is, if the first comparison value CQ1 is not smaller than the normal determination value A, the control unit 8 may perform the following. Good. The control unit 8 has a third detection value PQ3, which is a value of the compressor current when a predetermined third time longer than the second time has elapsed from the start time, and a predetermined third time longer than the third time from the start time. If the second comparison value CQ2 obtained by comparing with the fourth detection value PQ4, which is the value of the compressor current when four hours have passed, is smaller than the predetermined abnormality determination value B, the circuit state is determined. Switch from mode to normal operation mode.

The second comparison value CQ2 may be the difference between the third detection value PQ3 and the fourth detection value PQ4. In this case, the control unit 8 may calculate the second comparison value CQ2 by, for example, the following equation.
CQ2 = | PQ4-PQ3 | ... (3)

Alternatively, the first comparison value CQ1 may be an increase / decrease rate between the third detection value PQ3 and the fourth detection value PQ4. In this case, the control unit 8 may calculate the second comparison value CQ2 by, for example, the following equation.
CQ2 = | PQ4 / PQ3-1 | ... (4)

In the present embodiment, the error included in the third detected value PQ3 and the error included in the fourth detected value PQ4 cancel each other out, so that the second comparative value CQ2 is an error of the measured value by the measuring unit 7. Is not easily affected by. Therefore, in the present embodiment, by comparing the second comparison value CQ2 with the abnormality determination value B, the influence of the error can be surely reduced, so that the erroneous determination can be surely prevented.

As shown in FIG. 3, when the lower limit product is used, the degree of increase in the compressor current slows down and the compressor current is substantially constant around the time t3 when the third time elapses from the start time. Converge within range. In such a case, since the fourth detection value PQ4 is close to the third detection value PQ3, the second comparison value CQ2 is smaller than the abnormality determination value B. Therefore, if the second comparison value CQ2 is smaller than the abnormality determination value B, it can be determined that the refrigerant circuit 2 is normal, and there is no problem even if the normal operation mode is started.

On the other hand, if there is an abnormality in the element of the refrigerant circuit 2, for example, if there is an abnormality that the refrigerant flow path of the pressure reducing device 5 is blocked, the compressor current even after the third time has passed from the start time. The degree of increase in the compressor does not slow down, and the compressor current does not converge within a substantially constant range. In such a case, since the fourth detection value PQ4 has a large difference from the third detection value PQ3, the second comparison value CQ2 is not smaller than the abnormality determination value B. If the second comparison value CQ2 is not smaller than the abnormality determination value B, the control unit 8 stops the compressor 3. As a result, it is possible to reliably prevent the compressor 3 from continuing to operate in an abnormal state of the refrigerant circuit 2, so that the refrigerant circuit 2 can be protected.

In the present embodiment, the respective values of the third hour, the fourth hour, and the abnormality determination value B are determined as values that can determine that the refrigerant circuit 2 is normal when the lower limit product is used. There is. For example, the third time is set so that the related physical quantity converges within a substantially constant range when the lower limit product is used. In the present embodiment, when the lower limit product is used, it is possible to reliably prevent the word determination that the refrigerant circuit 2 is abnormal.

In the present embodiment, the normal operation is performed by performing the normal judgment using the first comparison value CQ1 and the normal judgment value A before the abnormality judgment using the second comparison value CQ2 and the abnormality judgment value B. It is more advantageous to start the mode early.

Hereinafter, an example of processing in the circuit state determination mode will be described with reference to the flowchart of FIG. After starting the compressor 3, the control unit 8 starts the circuit state determination mode. As step S1, the control unit 8 stores the first detection value PQ1 measured by the measurement unit 7 at the time t1 when only the first hour has elapsed from the start time. Next, as step S2, the control unit 8 stores the second detection value PQ2 measured by the measurement unit 7 at the time t2 when only the second time has elapsed from the start time. Next, in step S3, the control unit 8 determines whether or not the first comparison value CQ1 is smaller than the normal determination value A. When the first comparison value CQ1 is smaller than the normal determination value A, the control unit 8 determines in step S7 that the refrigerant circuit 2 is normal, ends the circuit state determination mode, and starts the normal operation mode. To do.

On the other hand, when the first comparison value CQ1 is equal to or higher than the normal determination value A, the control unit 8 continues the circuit state determination mode. In this case, as step S4, the control unit 8 stores the third detection value PQ3 measured by the measurement unit 7 at the time t3 when only the third time has elapsed from the start time. Next, as step S5, the control unit 8 stores the fourth detected value PQ4 measured by the measuring unit 7 at the time t4 when only the fourth time has elapsed from the start time. Next, in step S6, the control unit 8 determines whether or not the second comparison value CQ2 is smaller than the abnormality determination value B. When the second comparison value CQ2 is smaller than the abnormality determination value B, the control unit 8 determines in step S8 that the refrigerant circuit 2 is normal, ends the circuit state determination mode, and starts the normal operation mode. To do. In contrast, when the second comparison value CQ2 is equal to or higher than the abnormality determination value B, the control unit 8 determines in step S9 that the refrigerant circuit 2 is abnormal, and stops the compressor 3. , The operation of the refrigerant circuit 2 is terminated.

As described above, in the present embodiment, the normal operation mode can be started when the abnormality of the refrigerant circuit 2 is not detected. Further, when an abnormality in the refrigerant circuit 2 is detected, the operation of the refrigerant circuit 2 is stopped, so that the occurrence of a failure can be reliably prevented.

Embodiment 2.
Next, the second embodiment will be described, but the differences from the first embodiment described above will be mainly described, and the same or corresponding parts will be simplified or omitted.

The second embodiment is different from the first embodiment in that the compressor temperature is used as a related physical quantity instead of the compressor current. The compressor temperature is the temperature of the compressor 3. The measuring unit 7 has a detector that detects the compressor temperature. The compressor temperature may be, for example, the temperature of the shell included in the compressor 3. In the high-pressure shell type compressor 3, the inside of the shell is filled with the high-pressure refrigerant before being discharged from the compressor 3. The higher the pressure on the high pressure side of the refrigerant circuit 2, the higher the drive load of the compressor 3 tends to be. The higher the drive load of the compressor 3, the higher the compressor temperature tends to be. Therefore, it can be said that the compressor temperature is a kind of related physical quantity.

The change over time in the compressor temperature after the start of the compressor 3 shows the same tendency as the graph in FIG. In the second embodiment, the control unit 8 executes the same processing as that of the first embodiment by using the detected value of the compressor temperature instead of the detected value of the compressor current in the first embodiment. The same effect as that of Form 1 can be obtained.

Embodiment 3.
Next, the third embodiment will be described, but the differences from the first embodiment described above will be mainly described, and the same or corresponding parts will be simplified or omitted.

The third embodiment is different from the first embodiment in that the discharged refrigerant temperature is used as a related physical quantity instead of the compressor current. The discharged refrigerant temperature is the temperature of the refrigerant discharged from the compressor 3. The measuring unit 7 has a detector that detects the temperature of the discharged refrigerant.

The change with time of the discharged refrigerant temperature after the start of the compressor 3 shows the same tendency as the graph of FIG. In the third embodiment, the control unit 8 executes the same processing as in the first embodiment by using the detected value of the discharged refrigerant temperature instead of the detected value of the compressor current in the first embodiment. The same effect as that of the first form can be obtained.

Embodiment 4.
Next, the fourth embodiment will be described, but the differences from the first embodiment described above will be mainly described, and the same or corresponding parts will be simplified or omitted.

The fourth embodiment is different from the first embodiment in that the evaporator inlet temperature is used as a related physical quantity instead of the compressor current. The evaporator inlet temperature is the temperature of the refrigerant flowing into the evaporator 6. The measuring unit 7 has a detector that detects the temperature at the inlet of the evaporator.

FIG. 4 is a diagram showing an example of time-dependent changes in the related physical quantity after the start of the compressor 3 when the evaporator inlet temperature is used as the related physical quantity. FIG. 4 shows a graph of the related physical quantity when the central product decompression device 5 is used, a graph of the related physical quantity when the lower limit product decompression device 5 is used, and an abnormal product decompression device 5. A graph of related physical quantities when used is shown. The refrigerant flow rate of the decompression device 5 is in the order of central product> lower limit product> abnormal product. Therefore, the amount of decompression of the decompression device 5 under the same setting is in the order of central product <lower limit product <abnormal product, and the evaporator inlet temperature changes with time as shown in FIG. 4 due to the difference in the low pressure side refrigerant pressure. .. In the fourth embodiment, the control unit 8 executes the same process as that of the first embodiment by using the detected value of the evaporator inlet temperature instead of the detected value of the compressor current in the first embodiment. The same effect as that of Form 1 can be obtained.

Embodiment 5.
Next, the fifth embodiment will be described, but the differences from the first embodiment described above will be mainly described, and the same or corresponding parts will be simplified or omitted.

The fifth embodiment is different from the first embodiment in that the evaporator outlet temperature is used as a related physical quantity instead of the compressor current. The evaporator outlet temperature is the temperature of the refrigerant flowing out of the evaporator 6. The measuring unit 7 has a detector for detecting the evaporator outlet temperature.

The change with time of the evaporator outlet temperature after the start of the compressor 3 shows the same tendency as the graph of FIG. In the fifth embodiment, the control unit 8 executes the same processing as in the first embodiment by using the detected value of the evaporator outlet temperature instead of the detected value of the compressor current in the first embodiment. The same effect as that of Form 1 can be obtained.

The measuring unit 7 detects two or more of the compressor current, the compressor temperature, the discharged refrigerant temperature, the evaporator inlet temperature, and the evaporator outlet temperature described in each of the above-described embodiments as related physical quantities. May be good.

1 refrigeration cycle system, 2 refrigerant circuit, 3 compressor, 4 cooler, 5 decompression device, 6 evaporator, 7 measurement unit, 8 control unit, 8a processor, 8b memory

Claims (5)

A compressor that compresses the refrigerant, a cooler that cools the refrigerant compressed by the compressor, a decompression device that decompresses the refrigerant that has passed through the cooler, and a decompression device that evaporates the refrigerant that has passed through the decompression device. A refrigerant circuit with an evaporator and
A detection means for detecting a related physical quantity which is a physical quantity related to the state of the refrigerant circuit,
A control means for executing the circuit state determination mode after starting the compressor and before starting the normal operation mode for performing the refrigeration cycle operation by the refrigerant circuit.
With
The control means has a first detection value which is a value of the related physical quantity when the first time elapses from the start time of the circuit state determination mode, and a second time longer than the first time from the start time. If the first comparison value obtained by comparing with the second detection value, which is the value of the related physical quantity at the time of elapse, is smaller than the normal judgment value, the circuit state judgment mode is switched to the normal operation mode. If not, a refrigeration cycle system that continues the circuit state determination mode. When the circuit state determination mode is continued even after the second time has elapsed, the control means is the value of the related physical quantity at the time when the third time longer than the second time elapses from the start time. The second comparison value obtained by comparing the third detection value, which is the value of the related physical quantity at the time when the fourth time longer than the third time elapses from the start time, with the fourth detection value. The refrigeration cycle system according to claim 1, wherein when is smaller than the abnormality determination value, the circuit state determination mode is switched to the normal operation mode. The refrigeration cycle system according to claim 2, wherein the control means stops the compressor when the second comparison value is not smaller than the abnormality determination value. The detecting means is a current flowing through the compressor, a temperature of the compressor, a discharge refrigerant temperature which is the temperature of the refrigerant discharged from the compressor, and a temperature of the refrigerant flowing into the evaporator. The invention according to any one of claims 1 to 3, wherein at least one of the evaporator inlet temperature and the evaporator outlet temperature, which is the temperature of the refrigerant flowing out of the evaporator, is detected as the related physical quantity. Refrigeration cycle system. The refrigeration cycle system according to any one of claims 1 to 4, wherein the first comparison value is a difference or an increase / decrease rate between the first detection value and the second detection value.

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