Refrigeration and air conditioning equipment

Abstract

To provide a refrigerating air conditioner capable of specifying abnormality of a temperature sensor.SOLUTION: A refrigerating air conditioner includes: a refrigerant circuit in which a compressor, a condenser, a throttle device, and an evaporator are connected via piping so that a refrigerant is circulated therethrough; a first sensor for detecting an outlet temperature of one of the condenser and the evaporator; a second sensor for detecting an ambient temperature of one of the condenser and the evaporator; a third sensor for detecting a saturation temperature of the refrigerant flowing in one of the condenser and the evaporator or detecting a pressure for calculating the saturation temperature; and a control device for calculating temperature efficiency from a detection value of the first sensor, the second sensor, and the third sensor, or calculating an outlet temperature threshold from the detection value of the second sensor and the third sensor and a temperature efficiency threshold set in advance. The control device determines that the first sensor is abnormal when the temperature efficiency is higher than the temperature efficiency threshold or by a result of comparison between the detection value of the first sensor and the outlet temperature threshold.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a refrigeration and air conditioning device equipped with a temperature sensor. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is a technique for detecting abnormalities in a pressure sensor and a temperature sensor provided in a refrigeration and air conditioning device such as an air conditioner (see, for example, Patent Document 1).

[0003] Patent document 1 calculates the evaporation pressure of the refrigerant based on the refrigerant temperature detected by a temperature sensor installed in the evaporator, compares this evaporation pressure with the refrigerant pressure detected by a pressure sensor, and if the calculated value falls outside a specified range, determines that at least one of the pressure sensor and the temperature sensor is abnormal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-313125 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although the technology in Patent Document 1 can determine that at least one of the pressure sensor and the temperature sensor is abnormal, it cannot determine which sensor is abnormal. Therefore, even if the temperature sensor is abnormal, it cannot be identified.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a refrigeration and air conditioning device that is capable of identifying the occurrence of an abnormality in a temperature sensor. [Means for solving the problem]

[0007] The refrigeration and air conditioning apparatus according to the present disclosure comprises a refrigerant circuit in which a compressor, a condenser, a throttling device, and an evaporator are connected by piping and a refrigerant circulates; a first sensor that detects an outlet temperature of one of the condenser and the evaporator; a second sensor that detects an ambient temperature of the one of the condenser and the evaporator; a third sensor that detects a saturation temperature of the refrigerant flowing through the one of the condenser and the evaporator or detects a pressure for calculating the saturation temperature; and a control device that calculates a temperature efficiency from detection values ​​of the first sensor, the second sensor, and the third sensor, or calculates an outlet temperature threshold from the detection values ​​of the second sensor and the third sensor and a predetermined temperature efficiency threshold, and the control device determines that the first sensor is abnormal if the temperature efficiency is higher than the temperature efficiency threshold or based on the result of comparing the detection value of the first sensor with the outlet temperature threshold. Effect of the Invention

[0008] According to the refrigeration and air conditioning device of the present disclosure, when the temperature efficiency is higher than the temperature efficiency threshold value, or based on the result of comparing the detection value of the first sensor with the outlet temperature threshold value, it is determined that the first sensor that detects the outlet temperature of the condenser or evaporator is abnormal. In this way, according to the refrigeration and air conditioning device of the present disclosure, it is possible to identify that an abnormality has occurred in the first sensor, which is a temperature sensor. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of a refrigeration and air conditioning device according to a first embodiment. [Diagram 2] 4 is a diagram showing detection values ​​of the sensors of the refrigeration and air conditioning system according to the first embodiment when the sensors are normal. FIG. [Diagram 3] 4 is a diagram showing detection values ​​of each sensor when the condenser outlet temperature sensor of the refrigeration and air conditioning apparatus according to the first embodiment is abnormal. FIG. [Figure 4] 5 is a flowchart showing a control flow in a sensor abnormality determination mode of the refrigeration and air conditioning apparatus according to the first embodiment. [Diagram 5]6 is a flowchart showing a control flow in a sensor abnormality determination mode in a modified example of the refrigeration and air conditioning system according to the first embodiment. [Figure 6] FIG. 11 is a diagram showing the configuration of a refrigeration and air conditioning device according to a second embodiment. [Figure 7] 13 is a diagram showing detection values ​​of the sensors of the refrigeration and air conditioning system according to the second embodiment when the sensors are normal. FIG. [Figure 8] 13 is a diagram showing detection values ​​of each sensor when an evaporator outlet temperature sensor of a refrigeration and air conditioning system according to embodiment 2 is abnormal. FIG. [Figure 9] 10 is a flowchart showing a control flow in a sensor abnormality determination mode of the refrigeration and air conditioning apparatus according to the second embodiment. [Figure 10] 10 is a flowchart showing a control flow in a sensor abnormality determination mode in a modified example of the refrigeration and air conditioning system according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below. In addition, the size relationships of the components in the drawings may differ from the actual ones.

[0011] Embodiment 1 FIG. 1 is a diagram showing a configuration of a refrigeration and air conditioning system 100 according to the first embodiment. In the first embodiment, as shown in Fig. 1, a refrigeration and air conditioning apparatus 100 is exemplified as an air conditioner that performs cooling operation, in which one indoor unit 20 is connected to one outdoor unit 10 by a liquid pipe 41 and a gas pipe 42 (hereinafter referred to as refrigerant piping). Note that, although Fig. 1 shows a configuration in which the refrigeration and air conditioning apparatus 100 has one indoor unit 20, it may have a configuration in which multiple indoor units 20 are provided, in which case each indoor unit 20 is connected in parallel to the outdoor unit 10 by a refrigerant pipe.

[0012] The outdoor unit 10 includes a compressor 11, a condenser 12, a high-pressure sensor 16, a condenser outlet temperature sensor 53, and a condenser ambient temperature sensor 54. In the following, the condenser outlet temperature sensor 53 will also be referred to as a first temperature sensor, the condenser ambient temperature sensor 54 will also be referred to as a second temperature sensor, and the high-pressure sensor 16 will also be referred to as a third sensor.

[0013] The indoor unit 20 includes a throttling device 21 and an evaporator 22.

[0014] The refrigeration and air conditioning system 100 includes a refrigerant circuit 1 in which a compressor 11, a condenser 12, a throttling device 21, and an evaporator 22 are connected in sequence in a circular manner by refrigerant piping, and in which a refrigerant circulates. An azeotropic refrigerant is sealed in the refrigerant circuit 1. The refrigerant circuit 1 may be configured to be connected to a flow switching device such as a four-way valve, and such a configuration makes it possible to perform heating operation in addition to cooling operation.

[0015] The refrigeration and air conditioning device 100 also includes a control device 30, a notification unit 36, and an operation mode switching unit 37, and the notification unit 36 ​​and the operation mode switching unit 37 are connected to the control device 30. The notification unit 36 ​​and the operation mode switching unit 37 may be provided in the control device 30 as a part of the control device 30.

[0016] The compressor 11 is a fluid machine that draws in low-temperature, low-pressure gas refrigerant, compresses it, and discharges it as high-temperature, high-pressure gas refrigerant. When the compressor 11 operates, the refrigerant circulates in the refrigerant circuit 1. The compressor 11 is, for example, an inverter-driven type that can adjust the operating frequency. The operation of the compressor 11 is controlled by the control device 30.

[0017] The condenser 12 exchanges heat between the refrigerant and the outdoor air. A fan (not shown) may be provided near the condenser 12. In this case, the amount of heat dissipated to the outdoor air, i.e., the amount of heat exchanged, can be changed by changing the rotation speed of the fan.

[0018] The throttling device 21 adiabatically expands the refrigerant. The throttling device 21 is, for example, an electronic expansion valve or a temperature expansion valve. The opening degree of the throttling device 21 is controlled by the control device 30 so that the degree of superheat at the outlet of the evaporator 22 approaches a target value.

[0019] The evaporator 22 exchanges heat between the refrigerant and the indoor air. A fan (not shown) may be provided near the evaporator 22. In this case, the amount of heat absorbed from the indoor air, i.e., the amount of heat exchanged, can be changed by changing the rotation speed of the fan to change the air volume.

[0020] The high-pressure sensor 16 is provided on the discharge side of the compressor 11, detects the pressure of the refrigerant on the discharge side of the compressor 11, and outputs a detection signal to the control device 30. The high-pressure sensor 16 receives the refrigerant pressure with a diaphragm, detects it with a pressure-sensitive element via hydraulic pressure, and converts it into an electrical signal corresponding to the pressure and outputs it. The condensation temperature T (P16) is calculated from the detection value of the pressure detected by this high-pressure sensor 16. Note that instead of the high-pressure sensor 16, a condensation temperature sensor may be provided in the middle of the heat transfer tube constituting the condenser 12 to detect the temperature of the refrigerant flowing therethrough, i.e., the condensation temperature T (P16). In the following, the condensation temperature is also referred to as the saturation temperature.

[0021] The condenser outlet temperature sensor 53 is provided between the condenser 12 and the throttling device 21, detects the temperature T(53) of the refrigerant on the outlet side of the condenser 12 (hereinafter referred to as the condenser outlet temperature), and outputs a detection signal to the control device 30. The condenser ambient temperature sensor 54 is provided near the condenser 12, detects the temperature T(54) around the condenser 12 (hereinafter referred to as the condenser ambient temperature), and outputs a detection signal to the control device 30. The condenser outlet temperature sensor 53 and the condenser ambient temperature sensor 54 are, for example, thermistors whose resistance values ​​change depending on the temperature.

[0022] The control device 30 is configured, for example, by dedicated hardware or a CPU (Central Processing Unit, also called a central processing unit, processing unit, arithmetic unit, microprocessor, or processor) that executes a program stored in a storage unit 31 described later.

[0023] When the control device 30 is a dedicated hardware, the control device 30 corresponds to, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of these. Each of the functional units realized by the control device 30 may be realized by individual hardware, or each functional unit may be realized by a single piece of hardware.

[0024] When the control device 30 is a CPU, each function executed by the control device 30 is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the storage unit 31. The CPU realizes each function of the control device 30 by reading and executing the programs stored in the storage unit 31.

[0025] Note that some of the functions of the control device 30 may be realized by dedicated hardware, and some by software or firmware.

[0026] The control device 30 controls the compressor 11, the throttling device 21, etc., based on detection signals from various sensors provided in the refrigeration and air conditioning device 100 and operation signals from an operation unit (not shown) such as a remote control, and controls the operation of the entire refrigeration and air conditioning device 100. The control device 30 may be provided inside the outdoor unit 10 or the indoor unit 20, or may be provided outside the outdoor unit 10 and the indoor unit 20.

[0027] The control device 30 includes, as functional blocks related to the sensor abnormality determination, a storage unit 31, an extraction unit 32, a calculation unit 33, a comparison unit 34, and a determination unit 35. Here, the sensor abnormality determination refers to determining whether or not an abnormality has occurred in the temperature sensor in the refrigeration and air conditioning device 100.

[0028] The storage unit 31 stores various information, and includes, for example, a non-volatile semiconductor memory that allows data to be rewritten, such as a flash memory, an EPROM, and an EEPROM. The storage unit 31 may also include, for example, a non-volatile semiconductor memory that allows data to be rewritten, such as a ROM, or a volatile semiconductor memory that allows data to be rewritten, such as a RAM. The storage unit 31 stores, for example, temperature data and pressure data detected by each sensor. The temperature data and pressure data are periodically acquired during operation of the refrigeration and air conditioning device 100. The storage unit 31 also stores each threshold value, which will be described later.

[0029] The extraction unit 32 extracts data necessary for sensor abnormality determination, such as the detection values ​​of each sensor, from the data stored in the storage unit 31. Here, data obtained when the compressor 11 is operating is used for the sensor abnormality determination. This is because, when the compressor 11 is not operating, it is not possible to correctly determine whether or not a sensor abnormality has occurred.

[0030] The calculation unit 33 performs necessary calculations based on the data extracted by the extraction unit 32. The calculation unit 33 calculates the condensation temperature T(P16) from the pressure data detected by the high pressure sensor 16, for example.

[0031] The comparison section 34 compares the value obtained by the calculation in the calculation section 33 with a preset threshold value or the like, or compares the values ​​obtained by the calculation in the calculation section 33 with each other.

[0032] The determination unit 35 determines, based on the comparison result in the comparison unit 34, for example, whether or not an abnormality has occurred in the condenser outlet temperature sensor 53.

[0033] The notification unit 36 ​​notifies various types of information such as the occurrence of an abnormality in response to a command from the control device 30. The notification unit 36 ​​includes at least one of a display means for visually notifying information such as an indicator lamp or a monitor, and an audio output means for audibly notifying information such as a speaker.

[0034] The driving mode switching unit 37 receives a driving mode switching operation by the user. The driving mode switching unit 37 can be provided in, for example, the above-mentioned operation unit. When the driving mode switching unit 37 switches the driving mode, a signal is output from the driving mode switching unit 37 to the control device 30, and the control device 30 switches the driving mode based on the signal. The control device 30 has at least a normal driving mode and a sensor abnormality determination mode as driving modes.

[0035] Next, the operation of the refrigeration and air conditioning system 100 according to the first embodiment in the normal operation mode will be described.

[0036] The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the condenser 12. The gas refrigerant that flows into the condenser 12 exchanges heat with the outdoor air there, condenses into a high-pressure liquid refrigerant, and flows out of the condenser 12. The liquid refrigerant that flows out of the condenser 12 is decompressed by the throttling device 21, and flows into the evaporator 22 as a low-pressure two-layer refrigerant. The two-layer refrigerant that flows into the evaporator 22 then exchanges heat with the indoor air there, evaporates, and flows out of the evaporator 22 as a low-temperature, low-pressure gas refrigerant. The gas refrigerant that flows out of the evaporator 22 is sucked into the compressor 11, where it again becomes a high-temperature, high-pressure gas refrigerant and is discharged.

[0037] Next, factors that cause an abnormality in the condenser outlet temperature sensor 53 will be described.

[0038] The condenser outlet temperature sensor 53 is in close contact with the piping on the outlet side of the condenser 12 (hereinafter referred to as the outlet side piping) in order to accurately detect the temperature of the refrigerant on the outlet side of the condenser 12. Furthermore, the condenser outlet temperature sensor 53 is insulated by a heat insulating material together with the outlet side piping so as not to be affected by the ambient temperature of the condenser 12. Therefore, the cause of the occurrence of an abnormality in the condenser outlet temperature sensor 53 may be deterioration of the heat insulating material due to aging, deterioration of the heat insulating performance, peeling off of the heat insulating material, or the occurrence of a gap between the condenser outlet temperature sensor 53 and the outlet side piping, which may make the sensor more susceptible to the ambient temperature of the condenser 12. When such an abnormality occurs, the detection value of the condenser outlet temperature sensor 53 gradually decreases from the normal value, making it difficult to determine the abnormality.

[0039] In addition, since the air on the outlet side of condenser 12 has a higher temperature than the air on the inlet side of condenser 12 by the amount of heat exchanged in condenser 12, the ambient temperature of condenser 12 varies slightly depending on the position. Therefore, when the above-mentioned abnormality occurs, the degree to which the ambient temperature of condenser 12 affects the detection value of condenser outlet temperature sensor 53 differs depending on the position of condenser outlet temperature sensor 53.

[0040] Next, a method for detecting an abnormality in the condenser outlet temperature sensor 53 of the refrigeration and air conditioning system 100 according to the first embodiment will be described.

[0041] Fig. 2 is a diagram showing detection values ​​of each sensor when each sensor of the refrigeration and air conditioning apparatus 100 according to embodiment 1 is normal. Fig. 3 is a diagram showing detection values ​​of each sensor when the condenser outlet temperature sensor 53 of the refrigeration and air conditioning apparatus 100 according to embodiment 1 is abnormal.

[0042] When the detection values ​​of each sensor are normal, the relationship between T(54n), T(53n), and T(P16n) is as follows, as shown in Fig. 2. Here, T(54n) is the condenser ambient temperature detected by the condenser ambient temperature sensor 54 under normal conditions, and T(53n) is the condenser outlet temperature detected by the condenser outlet temperature sensor 53 under normal conditions. Also, T(P16n) is the condensation temperature calculated from the pressure detected by the high pressure sensor 16 under normal conditions.

[0043] T(54n)≦T(53n)≦T(P16n)

[0044] Next, when the condenser outlet temperature sensor 53 is abnormal, as shown in Fig. 3, the relationship between T(53a) and T(53n) is as follows: Here, T(53a) is the condenser outlet temperature detected by the condenser outlet temperature sensor 53 when abnormal.

[0045] T(53a) <T(53n)

[0046] This is because when an abnormality such as that described above occurs in the condenser outlet temperature sensor 53, the detection value of the condenser outlet temperature sensor 53 is affected by the condenser ambient temperature and gradually decreases from the normal value to approach the detection value of the condenser ambient temperature sensor 54.

[0047] Here, the condenser 12 can be designed using an index called temperature efficiency ηcond, which can be expressed by the following formula (1).

[0048] ηcond=(T(P16)-T(53)) / (T(P16)-T(54))...(1) T(P16): Condensation temperature [℃] T(53): Condenser outlet temperature [℃] T(54): Condenser ambient temperature [℃]

[0049] When the detection values ​​of each sensor are normal, the condenser 12 is designed so that the temperature efficiency ηcond is within a preset temperature efficiency threshold ηc_th, for example, 0.7. This is because the temperature difference between the air and the refrigerant that are heat exchanged in the condenser 12 can be made large up to a temperature efficiency ηcond of about 0.7, and the heat exchange efficiency per unit heat exchange area is good. However, when the temperature efficiency ηcond is higher than 0.7, the temperature difference between the air and the refrigerant that are heat exchanged in the condenser 12 becomes small, and the heat exchange efficiency per unit heat exchange area decreases, so that the condenser 12 needs to be enlarged to obtain the desired heat exchange capacity, which increases costs. Therefore, in order to suppress costs, it is desirable to set the temperature efficiency ηcond within 0.7 when designing the condenser 12.

[0050] When the condenser outlet temperature sensor 53 is abnormal, as shown in FIG. 3, T(53a) approaches T(54n), and as a result, the temperature efficiency ηcond becomes higher than the temperature efficiency threshold ηc_th.

[0051] From the above, in the first embodiment, a temperature efficiency threshold ηc_th is set and the temperature efficiency ηcond is calculated to detect an abnormality in the condenser outlet temperature sensor 53. Then, when the temperature efficiency ηcond is higher than the temperature efficiency threshold ηc_th, it can be determined that there is an abnormality, and when the temperature efficiency ηcond is equal to or lower than the temperature efficiency threshold ηc_th, it can be determined that there is a normality.

[0052] Next, a control flow during the sensor abnormality determination process of the refrigeration and air conditioning apparatus 100 according to the first embodiment will be described.

[0053] FIG. 4 is a flowchart showing a control flow in the sensor abnormality determination mode of the refrigeration and air conditioning apparatus 100 according to the first embodiment. The control device 30 switches from the normal operation mode to the sensor abnormality determination mode at predetermined time intervals and performs the abnormality determination process described below. Alternatively, when the control device 30 receives a switching operation to the abnormality detection mode by the user from the operation mode switching unit 37, it switches from the normal operation mode to the sensor abnormality determination mode and performs the abnormality determination process described below.

[0054] (Step S101) The control device 30 determines whether the compressor 11 is in operation. When the control device 30 determines that the compressor 11 is in operation (YES), the process proceeds to step S102. On the other hand, when the control device 30 determines that the compressor 11 is not in operation (NO), the sensor abnormality determination process ends. In this way, the sensor abnormality determination process ends when the compressor 11 is not in operation because the sensor abnormality detection cannot be performed correctly even if the sensor abnormality determination process is executed except when the compressor 11 is in operation.

[0055] (Step S102) The control device 30 judges whether or not the system is in a transient state. Here, a transient state refers to a state in which the operation is not stable, such as when the compressor 11 is started, or when the opening degree of the throttling device 21 fluctuates greatly and the amount of liquid refrigerant stored on the high-pressure side fluctuates. If the control device 30 judges that the system is not in a transient state (YES), the process proceeds to step S103. On the other hand, if the control device 30 judges that the system is in a transient state (NO), the sensor abnormality determination process ends. In this way, the sensor abnormality determination process ends when the system is in a transient state because the sensor abnormality detection cannot be performed correctly even if the sensor abnormality determination process is executed when the system is in a transient state.

[0056] (Step S103) The control device 30 acquires detection values ​​from the high pressure sensor 16, the condenser outlet temperature sensor 53, and the condenser ambient temperature sensor 54. Note that the process of step S103 is not limited to be performed after step S102, and may be performed before step S101 or before step S102.

[0057] (Step S104A) The control device 30 calculates the temperature efficiency ηcond based on the detection values ​​of the high pressure sensor 16, the condenser outlet temperature sensor 53, and the condenser ambient temperature sensor 54. The temperature efficiency ηcond is calculated using the above formula (1). After that, the process proceeds to step S105A.

[0058] (Step S105A) The control device 30 determines whether the temperature efficiency ηcond is higher than the temperature efficiency threshold ηc_th set in advance. If the control device 30 determines that the temperature efficiency ηcond is higher than the temperature efficiency threshold ηc_th (YES), the process proceeds to step S106. On the other hand, if the control device 30 determines that the temperature efficiency ηcond is not higher than the temperature efficiency threshold ηc_th (NO), the process proceeds to step S107.

[0059] (Step S106) The control device 30 determines that the condenser outlet temperature sensor 53 is abnormal, and notifies the fact that the condenser outlet temperature sensor 53 is abnormal through the notification unit 36. Thereafter, the sensor abnormality determination process ends.

[0060] (Step S107) The control device 30 determines that each sensor is normal, and the sensor abnormality determination process ends.

[0061] Next, a process performed by the refrigeration and air conditioning system 100 according to the first embodiment after a sensor abnormality is detected will be described. If an abnormality occurs in the condenser outlet temperature sensor 53 causing the detection value to drop, it is desirable to replace or perform maintenance on the condenser outlet temperature sensor 53 as soon as possible, since this will have an effect on the refrigeration and air conditioning device 100. However, if it is not possible to replace or perform maintenance on the condenser outlet temperature sensor 53, operation will be performed with the following restrictions.

[0062] The condenser outlet temperature sensor 53 is an important sensor used for refrigerant leakage detection. Therefore, when the detection value of the condenser outlet temperature sensor 53 is abnormal, the control device 30 does not perform the above-mentioned refrigerant leakage detection process.

[0063] Furthermore, if the compressor 11 is accelerated when a sensor abnormality occurs, the refrigerant accumulates on the high pressure side, increasing the high pressure pressure and causing a risk of malfunctioning of the refrigeration and air conditioning device 100, so when the control device 30 detects an abnormality in the condenser outlet temperature sensor 53, it does not accelerate the compressor frequency. Furthermore, if the throttling device 21 is opened too much when an abnormality occurs in the condenser outlet temperature sensor 53, the refrigerant will be sucked into the compressor 11 without evaporating in the evaporator 22, causing a risk of malfunctioning of the refrigeration and air conditioning device 100, so when the control device 30 detects an abnormality in the condenser outlet temperature sensor 53, it does not open the throttling device 21 too much.

[0064] Next, a modification of the refrigeration and air conditioning system 100 according to the first embodiment will be described.

[0065] In the refrigeration and air conditioning apparatus 100 of embodiment 1, in the sensor abnormality determination mode, the sensor abnormality determination process is performed using the temperature efficiency ηcond, but in a modified example of the refrigeration and air conditioning apparatus 100 of embodiment 1, the sensor abnormality determination process is performed using the condenser outlet temperature threshold value Tcd_th.

[0066] Here, the condenser outlet temperature threshold Tcd_th can be calculated by the following formula (2).

[0067] Tcd_th=T(P16)-ηc_th×(T(P16)-T(54))····(2) T(P16): Condensation temperature [℃] T(54): Condenser ambient temperature [℃] ηc_th: Temperature efficiency threshold [-]

[0068] The above formula (2) can be obtained by inputting ηc_th into ηcond in formula (1) and inputting Tcd_th into T(53).

[0069] As described above, in the modification of the first embodiment, a temperature efficiency threshold ηc_th is set and a condenser outlet temperature threshold Tcd_th is calculated to detect an abnormality in the condenser outlet temperature sensor 53. Then, when the detection value of the condenser outlet temperature sensor 53 is lower than the condenser outlet temperature threshold Tcd_th, it can be determined that an abnormality exists, and when the detection value of the condenser outlet temperature sensor 53 is equal to or higher than the condenser outlet temperature threshold Tcd_th, it can be determined that the normality exists.

[0070] FIG. 5 is a flowchart showing a flow of control in the sensor abnormality determination mode in a modification of the refrigeration and air conditioning system 100 according to the first embodiment.

[0071] 5 are the same processes as those already explained, so their explanation will be omitted. However, in step S103 in FIG. 5, in the explanation of step S103 above, "The process proceeds to step S104A" should be read as "The process proceeds to step S104B."

[0072] (Step S104B) The control device 30 calculates the condenser outlet temperature threshold Tcd_th. The calculation of the condenser outlet temperature threshold Tcd_th is performed using the above formula (2). After that, the process proceeds to step S105B.

[0073] (Step S105B) The control device 30 determines whether the condenser outlet temperature T(53), which is the detection value of the condenser outlet temperature sensor 53, is lower than the condenser outlet temperature threshold Tcd_th. If the control device 30 determines that the condenser outlet temperature T(53) is lower than the condenser outlet temperature threshold Tcd_th (YES), the process proceeds to step S106. On the other hand, if the control device 30 determines that the condenser outlet temperature T(53) is not lower than the condenser outlet temperature threshold Tcd_th (NO), the process proceeds to step S107.

[0074] As described above, the refrigeration and air conditioning device 100 according to the first embodiment includes a refrigerant circuit 1 in which a compressor 11, a condenser 12, a throttling device 21, and an evaporator 22 are connected by piping and a refrigerant circulates, a first sensor that detects the outlet temperature of one of the condenser 12 and the evaporator 22, a second sensor that detects the ambient temperature of one of the condenser 12 and the evaporator 22, a third sensor that detects the saturation temperature of the refrigerant flowing through one of the condenser 12 and the evaporator 22 or detects the pressure for calculating the saturation temperature, and a control device 30 that calculates the temperature efficiency from the detection values ​​of the first sensor, the second sensor, and the third sensor, or calculates the outlet temperature threshold from the detection values ​​of the second sensor and the third sensor and a preset temperature efficiency threshold. The control device 30 determines that the first sensor is abnormal when the temperature efficiency is higher than the temperature efficiency threshold, or based on the result of comparing the detection value of the first sensor with the outlet temperature threshold.

[0075] According to the refrigeration and air conditioning device 100 of the first embodiment, when the temperature efficiency is higher than the temperature efficiency threshold value, or based on the comparison result between the detection value of the first sensor and the outlet temperature threshold value, it is determined that the first sensor detecting the outlet temperature of the condenser 12 or the evaporator 22 is abnormal. In this way, according to the refrigeration and air conditioning device 100 of the first embodiment, it is possible to identify that an abnormality has occurred in the first sensor, which is a temperature sensor.

[0076] In the refrigeration and air conditioning system 100 according to the first embodiment, the first sensor detects the outlet temperature of the condenser 12, the second sensor detects the ambient temperature of the condenser 12, and the third sensor detects the condensation temperature. The control device 30 determines that the first sensor is abnormal when the detected value of the first sensor is lower than the outlet temperature threshold value.

[0077] According to the refrigeration and air conditioning system 100 according to the first embodiment, it is possible to identify that an abnormality has occurred in the condenser outlet temperature sensor 53, which is the first sensor that detects the outlet temperature of the condenser 12.

[0078] Furthermore, in the refrigeration and air conditioning system 100 according to the first embodiment, when the first sensor is abnormal, the control device 30 does not increase the compressor frequency.

[0079] According to the refrigeration and air conditioning system 100 according to the first embodiment, breakdowns in the refrigeration and air conditioning system 100 can be avoided.

[0080] Embodiment 2 Hereinafter, the second embodiment will be described, but explanations of parts that overlap with the first embodiment will be omitted, and parts that are the same as or equivalent to the first embodiment will be given the same reference numerals.

[0081] FIG. 6 is a diagram showing a configuration of a refrigeration and air conditioning system 100 according to the second embodiment. The refrigeration and air conditioning system 100 according to the second embodiment is different from the first embodiment in the sensors provided.

[0082] The outdoor unit 10 includes a compressor 11, a condenser 12, and a low-pressure sensor 18.

[0083] The indoor unit 20 includes a throttling device 21, an evaporator 22, an evaporator outlet temperature sensor 63, and an evaporator ambient temperature sensor 64. In the following, the evaporator outlet temperature sensor 63 will also be referred to as a first temperature sensor, the evaporator ambient temperature sensor 64 will also be referred to as a second temperature sensor, and the low-pressure sensor 18 will also be referred to as a third sensor.

[0084] The low-pressure sensor 18 is provided on the suction side of the compressor 11, detects the pressure on the suction side of the compressor 11, and outputs a detection signal to the control device 30. The low-pressure sensor 18 receives the pressure of the refrigerant with a diaphragm, detects it with a pressure-sensitive element via hydraulic pressure, and converts it into an electric signal according to the pressure and outputs it. The evaporation temperature T (P18) is calculated from the pressure detected by this low-pressure sensor 18. Note that instead of the low-pressure sensor 18, an evaporation temperature sensor may be provided in the middle of the heat transfer tube constituting the evaporator 22 to detect the temperature of the refrigerant flowing therethrough, that is, the evaporation temperature T (P18). In the following, the evaporation temperature is also referred to as the saturation temperature.

[0085] The evaporator outlet temperature sensor 63 is provided between the evaporator 22 and the compressor 11, detects the temperature T(63) of the refrigerant on the outlet side of the evaporator 22 (hereinafter referred to as the evaporator outlet temperature), and outputs a detection signal to the control device 30. The evaporator ambient temperature sensor 64 is provided near the evaporator 22, detects the temperature T(64) around the evaporator 22 (hereinafter referred to as the evaporator ambient temperature), and outputs a detection signal to the control device 30. The evaporator outlet temperature sensor 63 and the evaporator ambient temperature sensor 64 are, for example, thermistors whose resistance values ​​change depending on the temperature.

[0086] Next, factors that cause an abnormality in the evaporator outlet temperature sensor 63 will be described.

[0087] The evaporator outlet temperature sensor 63 is in close contact with the piping on the outlet side of the evaporator 22 (hereinafter referred to as the outlet side piping) in order to accurately detect the temperature of the refrigerant on the outlet side of the evaporator 22. Furthermore, the evaporator outlet temperature sensor 63 is insulated by a heat insulating material together with the outlet side piping so as not to be affected by the ambient temperature of the evaporator 22. Therefore, the cause of the occurrence of an abnormality in the evaporator outlet temperature sensor 63 may be deterioration of the heat insulating material due to aging, deterioration of the heat insulating performance, peeling off of the heat insulating material, or the occurrence of a gap between the evaporator outlet temperature sensor 63 and the outlet side piping, which may make the sensor more susceptible to the ambient temperature of the evaporator 22. When such an abnormality occurs, the detection value of the evaporator outlet temperature sensor 63 gradually rises from the normal value, making it difficult to determine the abnormality.

[0088] In addition, since the temperature of the air on the outlet side of the evaporator 22 is lower than that of the air on the inlet side of the evaporator 22 by the amount of heat exchanged in the evaporator 22, the ambient temperature of the evaporator 22 varies slightly depending on the position. Therefore, when the above-mentioned abnormality occurs, the degree to which the ambient temperature of the evaporator 22 affects the detection value of the evaporator outlet temperature sensor 63 differs depending on the position of the evaporator outlet temperature sensor 63.

[0089] Next, a method for detecting an abnormality in the evaporator outlet temperature sensor 63 of the refrigeration and air conditioning system 100 according to the second embodiment will be described.

[0090] Fig. 7 is a diagram showing detection values ​​of the sensors of the refrigeration and air conditioning apparatus 100 according to embodiment 2 when the sensors are normal. Fig. 8 is a diagram showing detection values ​​of the sensors of the refrigeration and air conditioning apparatus 100 according to embodiment 2 when the evaporator outlet temperature sensor 63 is abnormal.

[0091] When the detection values ​​of each sensor are normal, the relationship between T(64n), T(63n), and T(P18n) is as follows, as shown in Fig. 7. Here, T(64n) is the evaporator ambient temperature detected by the evaporator ambient temperature sensor 64 under normal conditions, and T(63n) is the evaporator outlet temperature detected by the evaporator outlet temperature sensor 63 under normal conditions. Also, T(P18n) is the evaporation temperature calculated from the pressure detected by the low pressure sensor 18 under normal conditions.

[0092] T(64n)≧T(63n)≧T(P18n)

[0093] Next, when the evaporator outlet temperature sensor 63 is abnormal, as shown in Fig. 8, the relationship between T(63a) and T(63n) is as follows: Here, T(63a) is the evaporator outlet temperature detected by the evaporator outlet temperature sensor 63 when abnormal.

[0094] T(63a)>T(63n)

[0095] This is because when an abnormality such as that described above occurs in the evaporator outlet temperature sensor 63, the detection value of the evaporator outlet temperature sensor 63 is affected by the evaporator ambient temperature and gradually rises from the normal value to approach the detection value of the evaporator outlet temperature sensor 63.

[0096] Here, the evaporator 22 can be designed using an index called temperature efficiency ηeva, which can be expressed by the following formula (3).

[0097] ηeva=(T(63)-T(P18)) / (T(64)-T(P18))...(3) T(P18): Evaporation temperature [℃] T(63): Evaporator outlet temperature [℃] T(64): Evaporator ambient temperature [℃]

[0098] When the detection values ​​of each sensor are normal, the evaporator 22 is designed so that the temperature efficiency ηeva is within a preset temperature efficiency threshold value ηe_th, for example, 0.5. This is because if the outlet state of the evaporator 22 is overheated into gas, the heat exchange efficiency decreases, and since the evaporator 22 is mounted in the indoor unit 20, it is desirable that it is as small as possible. Therefore, in order to achieve both a compact size and high performance of the evaporator 22, it is desirable to set the temperature efficiency ηeva within 0.5.

[0099] When the evaporator outlet temperature sensor 63 is abnormal, as shown in FIG. 8, T(63a) approaches T(64n), and as a result, the temperature efficiency ηeva becomes higher than the temperature efficiency threshold ηe_th.

[0100] From the above, in the second embodiment, a temperature efficiency threshold ηe_th is set and the temperature efficiency ηeva is calculated to detect an abnormality in the evaporator outlet temperature sensor 63. Then, when the temperature efficiency ηeva is higher than the temperature efficiency threshold ηe_th, it can be determined that there is an abnormality, and when the temperature efficiency ηeva is equal to or lower than the temperature efficiency threshold ηe_th, it can be determined that there is a normality.

[0101] Next, a control flow during the sensor abnormality determination process of the refrigeration and air conditioning system 100 according to the second embodiment will be described.

[0102] FIG. 9 is a flowchart showing a control flow in the sensor abnormality determination mode of the refrigeration and air conditioning system 100 according to the second embodiment. The control device 30 switches from the normal operation mode to the sensor abnormality determination mode at predetermined time intervals and performs the abnormality determination process described below. Alternatively, when the control device 30 receives a switching operation to the abnormality detection mode by the user from the operation mode switching unit 37, it switches from the normal operation mode to the sensor abnormality determination mode and performs the abnormality determination process described below.

[0103] (Step S201) The control device 30 determines whether the compressor 11 is in operation. When the control device 30 determines that the compressor 11 is in operation (YES), the process proceeds to step S202. On the other hand, when the control device 30 determines that the compressor 11 is not in operation (NO), the sensor abnormality determination process ends. In this way, the sensor abnormality determination process ends when the compressor 11 is not in operation because the sensor abnormality detection cannot be performed correctly even if the sensor abnormality determination process is executed except when the compressor 11 is in operation.

[0104] (Step S202) The control device 30 judges whether or not the system is in a transient state. Here, a transient state refers to a state in which the operation is not stable, such as when the compressor 11 is started, or when the opening degree of the throttling device 21 fluctuates greatly and the amount of liquid refrigerant stored on the high-pressure side fluctuates. If the control device 30 judges that the system is not in a transient state (YES), the process proceeds to step S203. On the other hand, if the control device 30 judges that the system is in a transient state (NO), the sensor abnormality determination process ends. In this way, the sensor abnormality determination process ends when the system is in a transient state because the sensor abnormality detection cannot be performed correctly even if the sensor abnormality determination process is executed when the system is in a transient state.

[0105] (Step S203) The control device 30 acquires detection values ​​from the low pressure sensor 18, the evaporator outlet temperature sensor 63, and the evaporator ambient temperature sensor 64. The process of step S203 is not limited to be performed after step S202, and may be performed before step S201 or before step S202.

[0106] (Step S204A) The control device 30 calculates the temperature efficiency ηeva based on the detection values ​​of the low pressure sensor 18, the evaporator outlet temperature sensor 63, and the evaporator ambient temperature sensor 64. The temperature efficiency ηeva is calculated using the above formula (3). After that, the process proceeds to step S205A.

[0107] (Step S205A) The control device 30 determines whether the temperature efficiency ηeva is higher than a preset temperature efficiency threshold ηe_th. If the control device 30 determines that the temperature efficiency ηeva is higher than the temperature efficiency threshold ηe_th (YES), the process proceeds to step S206. On the other hand, if the control device 30 determines that the temperature efficiency ηeva is not higher than the temperature efficiency threshold ηe_th (NO), the process proceeds to step S207.

[0108] (Step S206) The control device 30 determines that the evaporator outlet temperature sensor 63 is abnormal, and notifies the user through the notification unit 36 ​​that the evaporator outlet temperature sensor 63 is abnormal. Then, the sensor abnormality determination process ends.

[0109] (Step S207) The control device 30 determines that each sensor is normal, and the sensor abnormality determination process ends.

[0110] Next, a process performed after a sensor abnormality is detected in the refrigeration and air conditioning system 100 according to the second embodiment will be described. If an abnormality occurs in the evaporator outlet temperature sensor 63 causing the detection value to drop, it is desirable to replace or perform maintenance on the evaporator outlet temperature sensor 63 as soon as possible, since this will have an effect on the refrigeration and air conditioning system 100. However, if it is not possible to replace or perform maintenance on the evaporator outlet temperature sensor 63, operation is performed with the following restrictions.

[0111] The evaporator outlet temperature sensor 63 is an important sensor used for detecting an abnormality in the throttling device 21 and for detecting a heat transfer failure in the evaporator 22. Therefore, when the detection value of the evaporator outlet temperature sensor 63 is abnormal, the control device 30 does not perform the above-mentioned processes for detecting an abnormality in the throttling device 21 and for detecting a heat transfer failure in the evaporator 22.

[0112] Furthermore, if the compressor 11 is accelerated when a sensor abnormality occurs, the refrigerant accumulates on the high pressure side, increasing the high pressure pressure and causing a risk of malfunctioning of the refrigeration and air conditioning system 100, so the control device 30 does not accelerate the compressor frequency when it detects an abnormality in the evaporator outlet temperature sensor 63. Furthermore, if the throttling device 21 is opened too much when an abnormality occurs in the evaporator outlet temperature sensor 63, the refrigerant will be sucked into the compressor 11 without evaporating in the evaporator 22, causing a risk of malfunctioning of the refrigeration and air conditioning system 100, so the control device 30 does not open the throttling device 21 excessively when it detects an abnormality in the evaporator outlet temperature sensor 63.

[0113] Next, a modification of the refrigeration and air conditioning system 100 according to the second embodiment will be described.

[0114] In the refrigeration and air conditioning apparatus 100 of embodiment 2, in the sensor abnormality determination mode, the sensor abnormality determination process is performed using the temperature efficiency ηeva, but in a modified example of the refrigeration and air conditioning apparatus 100 of embodiment 2, the sensor abnormality determination process is performed using the evaporator outlet temperature threshold Ted_th.

[0115] Here, the evaporator outlet temperature threshold Ted_th can be calculated by the following formula.

[0116] Ted_th=T(P18)+ηe_th×(T(64)-T(P18))····(4) T(P18): Evaporation temperature [℃] T(64): Evaporator ambient temperature [℃] ηe_th: Temperature efficiency threshold [-]

[0117] The above equation (4) can be obtained by inputting ηe_th into ηeva in equation (3) and inputting Ted_th into T(63).

[0118] From the above, in the modification of the second embodiment, a temperature efficiency threshold ηe_th is set and an evaporator outlet temperature threshold Ted_th is calculated to detect an abnormality in the evaporator outlet temperature sensor 63. Then, when the detection value of the evaporator outlet temperature sensor 63 is higher than the evaporator outlet temperature threshold Ted_th, it can be determined that there is an abnormality, and when the detection value of the evaporator outlet temperature sensor 63 is equal to or lower than the evaporator outlet temperature threshold Ted_th, it can be determined that there is a normality.

[0119] FIG. 10 is a flowchart showing a control flow in the sensor abnormality determination mode in the modified example of the refrigeration and air conditioning system 100 according to the second embodiment.

[0120] 9 are the same processes as those already explained, so the explanation of those will be omitted. However, in step S203 in FIG 10, in the explanation of step S203 above, "The process proceeds to step S204A" should be read as "The process proceeds to step S204B."

[0121] (Step S204B) The control device 30 calculates the evaporator outlet temperature threshold Ted_th. The calculation of the evaporator outlet temperature threshold Ted_th is performed using the above-mentioned formula (4). After that, the process proceeds to step S205B.

[0122] (Step S205B) The control device 30 determines whether the evaporator outlet temperature T(63), which is the detection value of the evaporator outlet temperature sensor 63, is higher than the evaporator outlet temperature threshold Ted_th. When the control device 30 determines that the evaporator outlet temperature T(63) is higher than the evaporator outlet temperature threshold Ted_th (YES), the process proceeds to step S206. On the other hand, when the control device 30 determines that the evaporator outlet temperature T(63) is not higher than the evaporator outlet temperature threshold Ted_th (NO), the process proceeds to step S207.

[0123] As described above, in the modified example of the refrigeration and air conditioning apparatus 100 according to the second embodiment, the sensor abnormality determination process is performed using the evaporator outlet temperature threshold Ted_th. Therefore, when the refrigeration and air conditioning apparatus 100 is a multi-type in which a plurality of indoor units 20 having a common temperature efficiency threshold ηe_th are connected in parallel, the evaporator outlet temperature threshold Ted_th calculated from the temperature efficiency threshold ηe_th, the evaporation temperature, and the ambient temperature needs to be calculated once, and the evaporator outlet temperature threshold Ted_th can be used for determination of all of the indoor units 20, thereby reducing the amount of calculation.

[0124] As described above, in the refrigeration and air conditioning system 100 according to the second embodiment, the first sensor detects the outlet temperature of the evaporator 22, the second sensor detects the ambient temperature of the evaporator 22, and the third sensor detects the evaporation temperature. Then, the control device 30 determines that the first sensor is abnormal when the detected value of the first sensor is lower than the outlet temperature threshold value.

[0125] According to the refrigeration and air conditioning system 100 according to the second embodiment, an abnormality in the evaporator outlet temperature sensor 63, which is the first sensor that detects the outlet temperature of the evaporator 22, can be identified. [Explanation of symbols]

[0126] 1 refrigerant circuit, 10 outdoor unit, 11 compressor, 12 condenser, 16 high pressure sensor, 18 low pressure sensor, 20 indoor unit, 21 throttling device, 22 evaporator, 30 control device, 31 memory unit, 32 extraction unit, 33 calculation unit, 34 comparison unit, 35 judgment unit, 36 notification unit, 37 operation mode switching unit, 41 liquid pipe, 42 gas pipe, 53 condenser outlet temperature sensor, 54 condenser ambient temperature sensor, 63 evaporator outlet temperature sensor, 64 evaporator ambient temperature sensor, 100 refrigeration and air conditioning device.

Claims

1. a refrigerant circuit in which a compressor, a condenser, a throttling device, and an evaporator are connected by piping and in which a refrigerant circulates; a first sensor for detecting an outlet temperature of one of the condenser and the evaporator; a second sensor for detecting an ambient temperature of the one of the condenser and the evaporator; a third sensor that detects a saturation temperature of the refrigerant flowing through one of the condenser and the evaporator, or detects a pressure for calculating the saturation temperature; a control device that calculates a temperature efficiency from detection values ​​of the first sensor, the second sensor, and the third sensor, or calculates an outlet temperature threshold from the detection values ​​of the second sensor and the third sensor and a preset temperature efficiency threshold; The control device includes: When the temperature efficiency is higher than the temperature efficiency threshold value, or based on a comparison result between the detection value of the first sensor and the outlet temperature threshold value, it is determined that the first sensor is abnormal. Refrigeration and air conditioning equipment.

2. The first sensor detects an outlet temperature of the condenser, the second sensor detects an ambient temperature of the condenser, and the third sensor detects a condensation temperature; The control device includes: When the detection value of the first sensor is lower than the outlet temperature threshold value, it is determined that the first sensor is abnormal. The refrigeration and air conditioning system according to claim 1.

3. The first sensor detects an outlet temperature of the evaporator, the second sensor detects an ambient temperature of the evaporator, and the third sensor detects an evaporation temperature, The control device includes: When the detection value of the first sensor is higher than the outlet temperature threshold, it is determined that the first sensor is abnormal. The refrigeration and air conditioning system according to claim 1.

4. The third sensor is A pressure sensor provided on the discharge side of the compressor, or a temperature sensor provided on a heat transfer tube constituting the condenser. The refrigeration and air conditioning system according to claim 2.

5. The third sensor is A pressure sensor provided on the intake side of the compressor, or a temperature sensor provided on a heat transfer tube constituting the evaporator. The refrigeration and air conditioning system according to claim 3.

6. The control device includes: If the first sensor is abnormal, Do not increase the compressor frequency The refrigeration and air conditioning system according to any one of claims 1 to 5.

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