WO2022249502A1

WO2022249502A1 - Refrigeration and air-conditioning device

Info

Publication number: WO2022249502A1
Application number: PCT/JP2021/028876
Authority: WO
Inventors: 康敬落合; 宣明田崎; 和彦南条; 一宏小松; 冬樹佐藤
Original assignee: 三菱電機株式会社
Priority date: 2021-05-24
Filing date: 2021-08-04
Publication date: 2022-12-01
Also published as: JP2022179969A

Abstract

A refrigeration and air-conditioning device that comprises: a refrigerant circuit in which a refrigerant circulates through a compressor, a condenser, a throttling device, and an evaporator that are connected by piping; a first sensor that detects the discharge pressure of the compressor or detects a temperature for calculating the discharge pressure; a second sensor that detects the suction pressure of the compressor or detects a temperature for calculating the suction pressure; a third sensor that detects the discharge temperature of the compressor; a fourth sensor that detects the suction temperature of the compressor; and a control device that determines that the third sensor is abnormal when the adiabatic efficiency of the compressor as calculated on the basis of the discharge pressure, the suction pressure, the discharge temperature, and the suction temperature is higher than a preset upper limit or when the discharge temperature is lower than a discharge temperature threshold calculated on the basis of the discharge pressure, the suction pressure, and the suction temperature.

Description

refrigeration air conditioner

The present disclosure relates to a refrigerating and air-conditioning system with multiple sensors.

Conventionally, there is a technique for detecting anomalies in sensors provided in refrigerating and air-conditioning equipment such as air conditioners (see Patent Document 1, for example).

Patent document 1 is equipped with two sensors, finds the evaporating pressure of the refrigerant based on the refrigerant temperature detected by one sensor installed in the evaporator, and compares this evaporating pressure with the refrigerant pressure detected by the other sensor. However, when the calculated value is out of the predetermined range, it is determined that at least one of the two sensors is abnormal.

JP-A-8-313125

However, Patent Document 1 has the problem that it can determine that at least one of the two sensors is abnormal, but cannot determine which sensor is abnormal.

The present disclosure has been made to solve the above problems, and aims to provide a refrigerating and air-conditioning apparatus that can identify a sensor in which an abnormality has occurred.

A refrigerating and air-conditioning apparatus according to the present disclosure includes a refrigerant circuit in which a compressor, a condenser, a throttle device, and an evaporator are connected by piping, and a refrigerant circuit in which refrigerant circulates; A first sensor that detects the temperature for calculating, a second sensor that detects the suction pressure of the compressor or detects the temperature for calculating the suction pressure, and a second sensor that detects the discharge temperature of the compressor Three sensors, a fourth sensor for detecting the suction temperature of the compressor, the discharge pressure, the suction pressure, the discharge temperature, and the adiabatic efficiency of the compressor calculated based on the suction temperature are set in advance. or the discharge temperature is lower than a discharge temperature threshold calculated based on the discharge pressure, the suction pressure, and the suction temperature, it is determined that the third sensor is abnormal. and a control device for

According to the refrigerating and air-conditioning apparatus according to the present disclosure, when the adiabatic efficiency is greater than the preset upper limit value, or when the discharge temperature is lower than the discharge temperature threshold, it is determined that the third sensor is abnormal. A sensor in which an abnormality has occurred can be specified.

1 is a diagram showing the configuration of a refrigerating and air-conditioning apparatus according to Embodiment 1; FIG. 4 is a diagram showing a method of calculating compressor efficiency of the refrigerating and air-conditioning apparatus according to Embodiment 1. FIG. 4 is a diagram showing pressure and temperature ranges on the discharge side of the compressor of the refrigerating and air-conditioning apparatus according to Embodiment 1. FIG. 4 is a diagram showing normal values and abnormal values of a compressor discharge temperature sensor of the refrigerating and air-conditioning apparatus according to Embodiment 1; FIG. 4 is a diagram showing normal values and abnormal values of a high-pressure sensor of the refrigerating and air-conditioning system according to Embodiment 1; FIG. 4 is a flow chart showing the flow of control in the sensor abnormality determination mode of the refrigerating and air-conditioning apparatus according to Embodiment 1; 7 is a flow chart showing the flow of control in the sensor abnormality determination mode according to the modified example of the refrigerating and air-conditioning apparatus according to Embodiment 1; FIG. 7 is a diagram showing the configuration of a refrigerating and air-conditioning apparatus according to Embodiment 2; FIG. 10 is a diagram showing the enthalpy difference between the suction side and the discharge side of the compressor when the refrigerating and air-conditioning apparatus according to Embodiment 2 is normal and abnormal; 9 is a flow chart showing the flow of control in the sensor abnormality determination mode of the refrigerating and air-conditioning apparatus according to Embodiment 2;

Hereinafter, embodiments of the present disclosure will be described based on the drawings. It should be noted that the present disclosure is not limited by the embodiments described below. Also, in the following drawings, the size relationship of each component may differ from the actual size.

Embodiment 1.
FIG. 1 is a diagram showing the configuration of a refrigerating and air-conditioning apparatus 100 according to Embodiment 1. As shown in FIG.
In Embodiment 1, as a refrigerating and air-conditioning apparatus 100, as shown in FIG. 1, one indoor unit 20 is provided with a liquid pipe 41 and a gas pipe 42 (hereinafter referred to as refrigerant pipes) for one outdoor unit 10. , and illustrates an air conditioner that performs cooling operation. Although FIG. 1 shows a configuration in which the refrigerating and air-conditioning apparatus 100 includes one indoor unit 20, a configuration including a plurality of indoor units 20 may be used. machines 20 are connected in parallel by refrigerant pipes.

The outdoor unit 10 includes a compressor 11, a condenser 12, a high pressure sensor 16, a low pressure sensor 17, a compressor discharge temperature sensor 51, a condenser ambient temperature sensor 54, and a compressor suction temperature sensor 55. It has In the following, the high pressure sensor 16 is also called the first sensor, the low pressure sensor 17 is also called the second sensor, the compressor discharge temperature sensor 51 is also called the third sensor, and the compressor suction temperature sensor 55 is called the fourth sensor. Also called

The indoor unit 20 includes an expansion device 21 and an evaporator 22.

A refrigerating and air-conditioning apparatus 100 includes a refrigerant circuit 1 in which a compressor 11, a condenser 12, an expansion device 21, and an evaporator 22 are sequentially connected in a circular manner by refrigerant pipes, and refrigerant circulates. The refrigerant circuit 1 contains an azeotropic refrigerant such as R32 and R410A or a pseudo-azeotropic refrigerant. The refrigerant circuit 1 may be configured to be connected to a channel switching device such as a four-way valve, and such a configuration enables heating operation in addition to cooling operation.

The refrigerating and air-conditioning apparatus 100 also includes a control device 30, a notification unit 36, and an operation mode switching unit 37. The control device 30 is connected to the notification unit 36 and the operation mode switching unit 37, respectively. . Note that the notification unit 36 and the operation mode switching unit 37 may be provided in the control device 30 as part of the control device 30 .

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 through the refrigerant circuit 1 . The compressor 11 is, for example, an inverter-driven type whose operating frequency can be adjusted. Also, the operation of the compressor 11 is controlled by the control device 30 .

The condenser 12 performs heat exchange between the refrigerant and the outdoor air. A fan (not shown) may be provided in the vicinity of the condenser 12. In this case, the rotation speed of the fan is changed to change the air volume, thereby changing the amount of heat released to the outdoor air, that is, the amount of heat exchange. be able to.

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

The evaporator 22 performs heat exchange between the refrigerant and the room air. A fan (not shown) may be provided in the vicinity of the evaporator 22. In this case, by changing the number of revolutions of the fan, the amount of air is changed, and the amount of heat absorbed from the indoor air, that is, the amount of heat exchange is changed. be able to.

The high pressure sensor 16 is provided on the discharge side of the compressor 11, detects the pressure on the discharge side of the compressor 11 (hereinafter referred to as high pressure), and outputs a detection signal to the control device 30. The low pressure sensor 17 is provided on the suction side of the compressor 11 , detects pressure on the suction side of the compressor 11 (hereinafter referred to as low pressure), and outputs a detection signal to the control device 30 . The high-pressure sensor 16 and the low-pressure pressure sensor 17 receive, for example, the pressure of the refrigerant with a diaphragm, detect it with a pressure-sensitive element via hydraulic pressure, convert it into an electric signal corresponding to the pressure, and output it. Instead of the high-pressure sensor 16, a condensation temperature sensor may be provided at an intermediate portion of the heat transfer tube constituting the condenser 12 to detect the temperature of the refrigerant flowing therethrough, that is, the condensation temperature (saturation temperature). In this case, the pressure on the discharge side of the compressor 11 can be converted from the condensation temperature. Further, instead of the low-pressure sensor 17, an evaporation temperature sensor may be provided in the intermediate portion of the heat transfer tube constituting the evaporator 22 to detect the temperature of the refrigerant flowing therethrough, that is, the evaporation temperature (saturation temperature). In this case, the pressure on the suction side of the compressor 11 can be converted from the evaporation temperature.

The compressor discharge temperature sensor 51 is provided on the discharge side of the compressor 11 , detects the temperature on the discharge side of the compressor 11 (hereinafter referred to as discharge temperature), and outputs a detection signal to the control device 30 . Condenser ambient temperature sensor 54 is provided near condenser 12 , detects the ambient temperature of condenser 12 (hereinafter referred to as outside air temperature), and outputs a detection signal to control device 30 . Compressor suction temperature sensor 55 is provided on the suction side of compressor 11 , detects the temperature on the suction side of compressor 11 (hereinafter referred to as suction temperature), and outputs a detection signal to control device 30 . The compressor discharge temperature sensor 51, the condenser ambient temperature sensor 54, and the compressor suction temperature sensor 55 are, for example, thermistors whose resistance values change with temperature. Instead of the compressor suction temperature sensor 55, an evaporator outlet temperature sensor arranged on the outlet side of the evaporator 22 and detecting the temperature of the refrigerant flowing therethrough may be provided.

The control device 30 is, for example, dedicated hardware, or a CPU (also referred to as a central processing unit, a central processing unit, a processing unit, an arithmetic unit, a microprocessor, or a processor) that executes a program stored in a storage unit 31, which will be described later. Configured.

If the control device 30 is dedicated hardware, the control device 30 may be, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Applicable. Each functional unit implemented by the control device 30 may be implemented by separate hardware, or each functional unit may be implemented by one piece of hardware.

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

It should be noted that part of the functions of the control device 30 may be realized by dedicated hardware, and part of them may be realized by software or firmware.

The control device 30 operates the compressor 11, the expansion device 21, etc., based on detection signals from sensors provided in the refrigerating and air-conditioning apparatus 100 and operation signals from an operation unit (not shown) such as a remote controller. control and control the operation of the entire refrigerating and air-conditioning apparatus 100 . Note that 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 .

The control device 30 includes a storage unit 31, an extraction unit 32, a calculation unit 33, a comparison unit 34, and a determination unit 35 as functional blocks related to sensor abnormality determination. Here, the sensor abnormality determination is to determine whether or not the pressure sensor or the temperature sensor in the refrigerating and air-conditioning apparatus 100 is abnormal.

The storage unit 31 stores various types of information, and includes, for example, rewritable non-volatile semiconductor memory such as flash memory, EPROM, and EEPROM. Note that the storage unit 31 may also include, for example, a non-volatile semiconductor memory in which data cannot be rewritten, such as a ROM, or a volatile semiconductor memory in which data can be rewritten, such as a RAM. The storage unit 31 stores temperature data and pressure data detected by each sensor. Note that these temperature data and pressure data are acquired periodically during operation of the refrigerating and air-conditioning apparatus 100 . In addition, the storage unit 31 stores each threshold, which will be described later.

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

The calculation unit 33 performs necessary calculations based on the data extracted by the extraction unit 32. This calculation unit 33 calculates the heat insulation efficiency η and the like based on the detection values of the respective sensors.

The comparison unit 34 compares the value obtained by the calculation in the calculation unit 33 with a preset threshold or the like, or compares the values obtained by the calculation in the calculation unit 33 with each other. The comparison unit 34 compares the adiabatic efficiency η with a preset ηmax.

The determination unit 35 determines whether an abnormality has occurred in the pressure sensor or the temperature sensor based on the comparison result of the comparison unit 34 .

The notification unit 36 notifies various information such as the occurrence of an abnormality according to a command from the control device 30 . The notification unit 36 includes at least one of display means such as a display lamp or a monitor for visually notifying information, and audio output means such as a speaker for aurally notifying information.

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

Next, the operation of the refrigerating and air-conditioning apparatus 100 according to Embodiment 1 in the normal operation mode will be described.

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

Next, we will explain the causes of abnormalities in the pressure sensor and temperature sensor.

As described above, the pressure sensor such as the high-pressure sensor 16 receives, for example, the pressure of the refrigerant with a diaphragm, detects it with a pressure-sensitive element via hydraulic pressure, converts it into an electric signal corresponding to the detected pressure, and outputs it. is. Therefore, it is conceivable that, for example, deterioration of the oil-filled portion causes oil to escape, air to enter, and the detection value of the pressure sensor to gradually decrease from normal. This occurs because pressure propagation to the piezoelectric element is reduced when gas, which is a compressible fluid, is mixed into the oil portion. When this abnormality occurs, the detected value of the pressure sensor gradually decreases from the normal value, making it difficult to determine the abnormality.

In addition, the compressor discharge temperature sensor 51 is in close contact with the discharge-side pipe of the compressor 11 (hereinafter referred to as discharge-side pipe) in order to accurately detect the temperature on the discharge side of the compressor 11 . Furthermore, the compressor discharge temperature sensor 51 is insulated with a heat insulating material together with the discharge side pipe so as not to be affected by the outside air temperature. Therefore, the factors causing the abnormality of the compressor discharge temperature sensor 51 include deterioration of the heat insulating material due to deterioration over time, deteriorating the heat insulating performance, peeling off of the heat insulating material, or the connection between the compressor discharge temperature sensor 51 and the discharge side piping. It is conceivable that the influence of the outside air temperature may increase due to gaps occurring between them. When this abnormality occurs, the value detected by the compressor discharge temperature sensor 51 gradually decreases from the normal value, making it difficult to determine the abnormality.

Next, a method for detecting abnormality of the high-pressure sensor 16 and the compressor discharge temperature sensor 51 of the refrigerating and air-conditioning apparatus 100 according to Embodiment 1 will be described.

FIG. 2 is a diagram showing a method of calculating compressor efficiency of the refrigerating and air-conditioning apparatus 100 according to the first embodiment. The vertical axis in FIG. 2 indicates the pressure [MPaG], and the horizontal axis indicates the specific enthalpy [kJ/kg].

FIG. 2 shows the states of the suction side and the discharge side of the compressor 11 on the ph diagram, respectively, and illustrates the method of calculating the efficiency of the compressor. In FIG. 2, the point ps indicates the state of the suction side of the compressor 11, the point p0(P, T) indicates the state of the discharge side of the compressor 11, and the line s1 indicates the isentropic line. At this time, the adiabatic efficiency η of the compressor 11 can be expressed by the following formula.

η=Δh(s=const)/Δh(REF) (1)
Δh (s = const): enthalpy difference [kJ/kg] when isentropic changes
Δh (REF): Actual enthalpy difference between the suction side and the discharge side of the compressor 11 [kJ/kg]

The enthalpy differences Δh (s=const) and Δh(REF) can be calculated by inputting the pressure and temperature detected by each sensor into a function with pressure and temperature as parameters. Specifically, the enthalpy difference Δh (s=const) is obtained by inputting the pressure and temperature on the suction side of the compressor 11, that is, the detection values of the low-pressure sensor 17 and the compressor suction temperature sensor 55 into the function. Calculated by In addition, the enthalpy difference Δh (REF) is a function of the pressure and temperature on the suction side of the compressor 11 and the pressure and temperature on the discharge side of the compressor 11, that is, the high pressure sensor 16, the low pressure sensor 17, the compression It is calculated by inputting detection values of the machine discharge temperature sensor 51 and the compressor suction temperature sensor 55 . Note that the functions of the enthalpy differences Δh (s=const) and Δh(REF) are pre-stored in the storage unit 31 .

The adiabatic efficiency η varies depending on the specifications, operating conditions, environmental conditions, etc. of the compressor 11, but the compressor 11 is designed so that the adiabatic efficiency η is within a certain range. That is, the compressor 11 is designed so that the adiabatic efficiency η is equal to or greater than the minimum adiabatic efficiency ηmin and less than or equal to the maximum adiabatic efficiency ηmax (ηmin≦η≦ηmax), and this range is the normal range. Note that the minimum adiabatic efficiency ηmin is, for example, 0.5, and the maximum adiabatic efficiency ηmax is, for example, 0.9. Also, it is possible to estimate the approximate value of the adiabatic efficiency η depending on the suction state of the compressor 11 and the pressure difference between the suction side and the discharge side of the compressor 11 . Note that the value of the adiabatic efficiency η is smaller than 1 in the actual compressor 11 at best.

FIG. 3 is a diagram showing ranges of pressure and temperature on the discharge side of the compressor 11 of the refrigerating and air-conditioning apparatus 100 according to the first embodiment. The vertical axis in FIG. 3 indicates pressure [MPaG], and the horizontal axis indicates specific enthalpy [kJ/kg].

FIG. 3 shows the highest adiabatic efficiency ηmax and the lowest adiabatic efficiency ηmin on the ph diagram. The adiabatic efficiency η has a range depending on the specifications of the compressor 11, the operating state, and the environmental conditions. ηmax or less. Similarly, the pressure and temperature also have a range, and under normal conditions, the pressure is a value between the minimum pressure P (ηmin) and the maximum pressure P (ηmax), and the temperature is the minimum temperature T (ηmax). The value is equal to or lower than the maximum temperature T(ηmin).

Therefore, p0(P, T) with the pressure P and the temperature T as parameters is, under normal conditions, as shown in FIG. 3, the minimum adiabatic efficiency ηmin, the maximum adiabatic efficiency It exists in a range surrounded by pressure P(ηmax), minimum temperature T(ηmax), and maximum temperature T(ηmin).

FIG. 4 is a diagram showing normal values and abnormal values of the compressor discharge temperature sensor 51 of the refrigerating and air-conditioning apparatus 100 according to the first embodiment. The vertical axis in FIG. 4 indicates pressure [MPaG], and the horizontal axis indicates specific enthalpy [kJ/kg].

FIG. 4 shows on the ph diagram how the detected value of the compressor discharge temperature sensor 51 diverges from the normal p0, passes through the boundary p1 between normal and abnormal, and changes to an abnormal value pTab. It is a diagram showing. Although the detected value of the compressor discharge temperature sensor 51 changes depending on the operating state, environmental conditions, individual differences of sensors, etc., it stays within the normal range in normal times. However, when an abnormality occurs in the compressor discharge temperature sensor 51 as described above, the detected value of the compressor discharge temperature sensor 51 decreases from p0 to p1 and then to pTab, deviating from the normal range. Therefore, when p0 deviates from the normal range, abnormality of the compressor discharge temperature sensor 51 can be determined.

FIG. 5 is a diagram showing normal values and abnormal values of the high-pressure sensor 16 of the refrigerating and air-conditioning apparatus 100 according to Embodiment 1. FIG. The vertical axis in FIG. 5 indicates pressure [MPaG], and the horizontal axis indicates specific enthalpy [kJ/kg].

FIG. 5 shows, on the ph diagram, how the detected value of the high-pressure sensor 16 deviates from the normal p0, passes through the boundary p3 between normal and abnormal, and changes to the abnormal value pPab. It is a diagram. The detection value of the high-pressure sensor 16 changes depending on the operating state, environmental conditions, individual differences of the sensors, etc., but it stays within the normal range under normal conditions. However, when an abnormality occurs in the high pressure sensor 16 as described above, the detection value of the high pressure sensor 16 drops from p0 to p3 and then to pPab, deviating from the normal range. Therefore, when p0 deviates from the normal range, abnormality of the high pressure sensor 16 can be determined.

Next, the flow of control during the sensor abnormality determination process of the refrigerating and air-conditioning apparatus 100 according to Embodiment 1 will be described.

FIG. 6 is a flow chart showing the control flow of the refrigerating and air-conditioning apparatus 100 according to Embodiment 1 in the sensor abnormality determination mode.
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 receiving a user's operation to switch to the abnormality detection mode from the operation mode switching unit 37, the control device 30 switches from the normal operation mode to the sensor abnormality determination mode, and performs the abnormality determination process described below.

(Step S101)
Control device 30 determines whether 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. Thus, the reason why the sensor abnormality determination process ends when the compressor 11 is not in operation is that the sensor abnormality detection is correctly performed even if the sensor abnormality determination process is executed when the compressor 11 is not in operation. This is because it is not possible to

(Step S102)
Control device 30 determines whether or not there is a transient state. Here, the transient state is, for example, when the compressor 11 is started, or when the opening degree of the expansion device 21 fluctuates greatly and the amount of liquid refrigerant stored on the high pressure side fluctuates. It is in a state of not doing so. When the control device 30 determines that the state is not in a transient state (YES), the process proceeds to step S103. On the other hand, when the control device 30 determines that the state is in a transient state (NO), the sensor abnormality determination process ends. The reason why the sensor abnormality determination process is terminated in the transient state is that even if the sensor abnormality determination process is executed in the transient state, the sensor abnormality detection cannot be performed correctly.

(Step S103)
Control device 30 acquires detection values from high pressure sensor 16, low pressure sensor 17, compressor discharge temperature sensor 51, and compressor suction temperature sensor 55, respectively. After that, the process proceeds to step S104A. Note that the process of step S103 is not limited to after step S102, and may be performed before step S101 or before step S102.

(Step S104A)
Controller 30 calculates adiabatic efficiency η based on the values detected by high pressure sensor 16 , low pressure sensor 17 , compressor discharge temperature sensor 51 , and compressor suction temperature sensor 55 . Note that the calculation of the adiabatic efficiency η is performed using the above equation (1). After that, the process proceeds to step S105A.

(Step S105A)
The control device 30 determines whether or not the adiabatic efficiency η is higher than a preset maximum adiabatic efficiency ηmax. When the control device 30 determines that the adiabatic efficiency η is higher than the maximum adiabatic efficiency ηmax (YES), the process proceeds to step S106. On the other hand, when control device 30 determines that adiabatic efficiency η is not higher than maximum adiabatic efficiency ηmax (NO), the process proceeds to step S107A.

(Step S106)
The controller 30 determines that the compressor discharge temperature sensor 51 is abnormal, and notifies that the compressor discharge temperature sensor 51 is abnormal by the notification unit 36 . After that, the sensor abnormality determination process ends.

(Step S107A)
The control device 30 determines whether or not the adiabatic efficiency η is lower than a preset minimum adiabatic efficiency ηmin. When the control device 30 determines that the adiabatic efficiency η is lower than the minimum adiabatic efficiency ηmin (YES), the process proceeds to step S108. On the other hand, when the control device 30 determines that the adiabatic efficiency η is not lower than the minimum adiabatic efficiency ηmin (NO), the process proceeds to step S109.

(Step S108)
The control device 30 determines that the high pressure sensor 16 is abnormal, and notifies the high pressure sensor 16 of the abnormality by the notification unit 36 . After that, the sensor abnormality determination process ends.

(Step S109)
Control device 30 determines that each sensor is normal, and terminates the sensor abnormality determination process.

Next, processing after sensor abnormality detection of the refrigerating and air-conditioning apparatus 100 according to Embodiment 1 will be described.
Conventionally, when an abnormality occurs in the compressor discharge temperature sensor 51 and the detection value becomes low, the refrigerating and air-conditioning system 100 may malfunction. The compressor 11 is stopped even when there is an abnormality. However, in Embodiment 1, the abnormal sensor can be specified, and when the compressor discharge temperature sensor 51 is abnormal, the discharge state of the compressor 11 can be estimated without using the abnormal sensor. Therefore, in Embodiment 1, it is possible to operate the compressor 11 without stopping it even after the sensor abnormality is detected.

However, if the speed of the compressor 11 is increased when a sensor abnormality occurs, the refrigerant will accumulate on the high pressure side and the high pressure will increase, which may cause the refrigerating and air-conditioning apparatus 100 to malfunction. is detected, the compressor frequency is not increased. Further, if the expansion device 21 is closed too much when a sensor abnormality occurs, the refrigerant is stored on the high pressure side and the high pressure increases, which may cause the refrigerating and air-conditioning apparatus 100 to malfunction. When it is detected, the diaphragm device 21 is not closed.

Next, a modification of the refrigerating and air-conditioning apparatus 100 according to Embodiment 1 will be described.

In the refrigerating and air-conditioning apparatus 100 according to Embodiment 1, the sensor abnormality determination process is performed using the adiabatic efficiency η in the sensor abnormality determination mode. Sensor abnormality determination processing is performed using the temperature threshold value Td_s_th and the high pressure threshold value Pd_s_th.

Here, the discharge temperature Td can be expressed as a function fTd with Pd, Ps, Ts, and η as arguments, as in Equation (2) below. Also, the high pressure Pd can be expressed as a function fPd with Ps, Td, Ts, and η as arguments, as in the following equation (3).

Td=fTd (Pd, Ps, Ts, η) (2)
Pd: Discharge pressure [MPaG]
Ps: suction pressure [MPaG]
Ts: Suction temperature [°C]
η: Thermal insulation efficiency [-]

Pd=fPd (Ps, Td, Ts, η) (3)
Ps: suction pressure [MPaG]
Td: discharge temperature [°C]
Ts: Suction temperature [°C]
η: Thermal insulation efficiency [-]

Then, the discharge temperature threshold Td_s_th can be expressed by a function fTd in which ηmax, which is a value preset to η in equation (2), is input, and the high pressure threshold Pd_s_th is preset to η in equation (3). It is possible to express the value ηmin as the input function fPd. In other words, the ejection temperature threshold Td_s_th can be expressed as a function fTd with Pd, Ps, Ts, and ηmax as arguments, as in Equation (2)' below. Also, the high-pressure threshold Pd_s_th can be expressed as a function fPd with Ps, Td, Ts, and ηmin as arguments, as in Equation (3)' below.

　Td_s_th = fTd (Pd, Ps, Ts, ηmax) (2)'

　Pd_s_th=fPd (Ps, Td, Ts, ηmin) (3)'

FIG. 7 is a flow chart showing the flow of control in the sensor abnormality determination mode according to the modified example of the refrigerating and air-conditioning apparatus 100 according to the first embodiment.

Note that steps S101 to S103, S106, and S108 to S109 in FIG. 7 are the same processes as those already explained, so explanations thereof will be omitted. However, in step S103 of FIG. 7, "the process proceeds to step S104A" in the above description of step S103 should be read as "the process proceeds to step S104B."

(Step S104B)
Controller 30 calculates discharge temperature threshold Td_s_th and high pressure threshold Pd_s_th based on the values detected by high pressure sensor 16 , low pressure sensor 17 , compressor discharge temperature sensor 51 , and compressor suction temperature sensor 55 . The discharge temperature threshold value Td_s_th and the high pressure threshold value Pd_s_th are calculated using the above equations (2)′ and (3)′. After that, the process proceeds to step S105B.

(Step S105B)
The control device 30 determines whether or not the discharge temperature Td, which is the value detected by the compressor discharge temperature sensor 51, is lower than the discharge temperature threshold value Td_s_th. When the control device 30 determines that the ejection temperature Td is lower than the ejection temperature threshold value Td_s_th (YES), the process proceeds to step S106. On the other hand, when the control device 30 determines that the ejection temperature Td is not lower than the ejection temperature threshold value Td_s_th (NO), the process proceeds to step S107B.

(Step S107B)
The control device 30 determines whether the high pressure Pd, which is the value detected by the high pressure sensor 16, is lower than the high pressure threshold value Pd_s_th. When the control device 30 determines that the high pressure Pd is lower than the high pressure threshold value Pd_s_th (YES), the process proceeds to step S108. On the other hand, when the control device 30 determines that the high pressure Pd is not lower than the high pressure threshold value Pd_s_th (NO), the process proceeds to step S109.

As described above, the refrigerating and air-conditioning apparatus 100 according to Embodiment 1 includes the refrigerant circuit 1 in which the compressor 11, the condenser 12, the expansion device 21, and the evaporator 22 are connected by pipes and the refrigerant circulates. The refrigerating and air-conditioning apparatus 100 also includes a first sensor for detecting the discharge pressure of the compressor 11 or for detecting the temperature for calculating the discharge pressure, and a first sensor for detecting the suction pressure of the compressor 11 or for calculating the suction pressure. a second sensor that detects the temperature of the compressor 11; a third sensor that detects the discharge temperature of the compressor 11; and a fourth sensor that detects the suction temperature of the compressor 11. Further, the refrigerating and air-conditioning apparatus 100 operates when the adiabatic efficiency of the compressor 11 calculated based on the discharge pressure, the suction pressure, the discharge temperature, and the suction temperature is higher than a preset upper limit value, or when the discharge temperature exceeds the discharge pressure , and a control device 30 that determines that the third sensor is abnormal when the temperature is lower than a discharge temperature threshold calculated based on the suction pressure and the suction temperature.

According to the refrigerating and air-conditioning apparatus 100 according to Embodiment 1, it is determined that the third sensor is abnormal when the adiabatic efficiency is greater than the preset upper limit value or when the discharge temperature is lower than the discharge temperature threshold. do. Therefore, it is possible to identify the sensor in which the abnormality has occurred, and particularly to identify the abnormality of the third sensor. Moreover, since the sensor in which the abnormality has occurred can be identified, the cause of the abnormality can be identified, and the location of the abnormality can be quickly restored. As a result, the abnormal period of the refrigerating and air-conditioning apparatus 100 can be shortened, and the time during which it is operated in the abnormal state can be shortened.

It should be noted that when the pressure sensor is abnormal, the detected value is lower than in normal times, and as a result, the refrigerating and air-conditioning apparatus 100 is controlled at a higher pressure than in normal times. If the refrigerating and air-conditioning apparatus 100 is controlled at a higher pressure, the power consumption of the compressor 11 will increase, resulting in poor energy efficiency and an environmentally unfriendly operation. Therefore, by performing the sensor abnormality determination described in Embodiment 1, it is possible to shorten the time during which the refrigerating and air-conditioning apparatus 100 is operated in an abnormal state. Cost can be reduced.

Further, in the refrigerating and air-conditioning apparatus 100 according to Embodiment 1, the control device 30 detects that the first sensor is Judged as abnormal.

According to the refrigerating and air-conditioning apparatus 100 according to Embodiment 1, it is possible to identify an abnormality in the first sensor.

Also, in the refrigerating and air-conditioning apparatus 100 according to Embodiment 1, the control device 30 does not increase the compressor frequency when any sensor is abnormal.

According to the refrigerating and air-conditioning apparatus 100 according to Embodiment 1, it is possible to prevent the refrigerating and air-conditioning apparatus 100 from breaking down.

Embodiment 2.
Embodiment 2 will be described below, but descriptions of parts that overlap with those of Embodiment 1 will be omitted, and parts that are the same as or correspond to those of Embodiment 1 will be given the same reference numerals.

FIG. 8 is a diagram showing the configuration of a refrigerating and air-conditioning apparatus 100 according to Embodiment 2. As shown in FIG.
The outdoor unit 10 according to Embodiment 2 includes a compressor input sensor 56 and a compressor frequency sensor 57 in addition to the configuration of Embodiment 1. Note that, hereinafter, the compressor input sensor 56 is also referred to as a fifth sensor, and the compressor frequency sensor 57 is also referred to as frequency acquisition means.

A compressor input sensor 56 is provided in the compressor 11 to detect a compressor input value and output a detection signal to the control device 30 . Compressor input sensor 56 is, for example, a watt meter. The compressor frequency sensor 57 is provided in the compressor 11 , detects the compressor frequency for calculating the refrigerant circulation amount of the refrigerant circuit 1 , and outputs a detection signal to the control device 30 . Compressor frequency sensor 57 is, for example, a vibration sensor or an acceleration sensor. Note that instead of the value detected by the compressor frequency sensor 57, the indicated frequency to the compressor 11 may be used to calculate the refrigerant circulation amount.

FIG. 9 is a diagram showing the enthalpy difference between the suction side and the discharge side of the compressor 11 when the refrigerating and air-conditioning apparatus 100 according to Embodiment 2 is normal and abnormal. The vertical axis in FIG. 9 indicates pressure [MPaG], and the horizontal axis indicates specific enthalpy [kJ/kg].

9 shows, on the ph diagram, the normal value p0 of the high pressure sensor 16 and the compressor discharge temperature sensor 51, the abnormal value pPab of the high pressure sensor 16, the abnormal value pTab of the compressor discharge temperature sensor 51, and The enthalpy differences Δh(REF), Δh(Pab), and Δh(Tab) between the suction side and the discharge side of the compressor 11 at that time are shown, respectively.

As described above, the enthalpy difference Δh between the suction side and the discharge side of the compressor 11 can be obtained from the ph diagram shown in FIG. 9, but it can also be calculated by the following formula.

Δh(w)=W(w)/Gr (4)
W (w): compressor input value [W]
Gr: Refrigerant circulation amount [kg/s]

Also, the refrigerant circulation amount Gr can be calculated by the following formula.

Gr=F×v×ηv×ρs (5)
F: Compressor frequency [Hz]
v: Compressor displacement [m ³ ]
ηv: Compressor volumetric efficiency [-]
ρs: Compressor suction density [kg/m ³ ]
Note that v and ηv are constant values determined from the design specifications of the compressor 11 used in the refrigerating and air-conditioning system 100 , and ρs is a refrigerant physical property value determined from the suction temperature and suction pressure of the compressor 11 .

Further, the compressor input estimated value W (REF) is calculated by adding the refrigerant circulation amount Gr to the enthalpy difference Δh (REF) between the suction side and the discharge side of the compressor 11 obtained from the ph diagram. You can also That is, the compressor input estimated value W(REF) can also be calculated by the following formula.

W(REF)=Δh(REF)×Gr (6)
Δh (REF): Actual enthalpy difference between suction side and discharge side of compressor 11 Gr: Refrigerant circulation amount [kg/s]

Then, by comparing the estimated compressor input value W(REF) and the compressor input value W(w) detected by the compressor input sensor 56, the high pressure sensor 16 and the compressor discharge Abnormality detection of the temperature sensor 51 can be performed.

W(REF)=W(w): Normal W(REF)<W(w): Compressor discharge temperature sensor 51 malfunction or compressor input sensor 56 malfunction W(w)<W(REF): High pressure sensor 16 Abnormality, or compressor input sensor 56 abnormality

Also, it is calculated by dividing the actual enthalpy difference Δh (REF) between the suction side and the discharge side of the compressor 11 and the compressor input value W (w), which is the detection value of the compressor input sensor 56, by the refrigerant circulation amount Gr. Then, the enthalpy difference Δh(w) between the suction side and the discharge side of the compressor 11 is compared. By doing so, abnormality detection of the high pressure sensor 16 and the compressor discharge temperature sensor 51 can be performed as described below.

Δh(REF)=Δh(w): Normal Δh(REF)<Δh(w): Compressor discharge temperature sensor 51 malfunction or compressor input sensor 56 malfunction Δh(w)<Δh(REF): High pressure sensor 16 Abnormality, or compressor input sensor 56 abnormality

Next, the flow of control during the sensor abnormality determination process of the refrigerating and air-conditioning apparatus 100 according to Embodiment 2 will be described.

FIG. 10 is a flow chart showing the flow of control in the sensor abnormality determination mode of the refrigerating and air-conditioning apparatus 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 receiving a user's operation to switch to the abnormality detection mode from the operation mode switching unit 37, the control device 30 switches from the normal operation mode to the sensor abnormality determination mode, and performs the abnormality determination process described below.

(Step S201)
Control device 30 determines whether 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. Thus, the reason why the sensor abnormality determination process ends when the compressor 11 is not in operation is that the sensor abnormality detection is correctly performed even if the sensor abnormality determination process is executed when the compressor 11 is not in operation. This is because it is not possible to

(Step S202)
Control device 30 determines whether or not there is a transient state. Here, the transient state is, for example, when the compressor 11 is started, or when the opening degree of the expansion device 21 fluctuates greatly and the amount of liquid refrigerant stored on the high pressure side fluctuates. It is in a state of not doing so. When the control device 30 determines that it is not in a transient state (YES), the process proceeds to step S203. On the other hand, when the control device 30 determines that the state is in a transient state (NO), the sensor abnormality determination process ends. The reason why the sensor abnormality determination process is terminated in the transient state is that even if the sensor abnormality determination process is executed in the transient state, the sensor abnormality detection cannot be performed correctly.

(Step S203)
Control device 30 acquires detection values from high pressure sensor 16, low pressure sensor 17, compressor discharge temperature sensor 51, compressor intake temperature sensor 55, compressor input sensor 56, and compressor frequency sensor 57, respectively. After that, the process proceeds to step S204. Note that the process of step S203 is not limited to after step S202, and may be performed before step S201 or before step S202.

(Step S204)
The controller 30 calculates the estimated compressor input value W ( REF) is calculated. Note that the compressor input estimated value W(REF) is calculated using the above equation (6). After that, the process proceeds to step S205.

(Step S205)
The controller 30 determines whether the estimated compressor input value W(REF) is smaller than the compressor input value W(w) detected by the compressor input sensor 56 . If controller 30 determines that estimated compressor input value W(REF) is smaller than compressor input value W(w) (YES), the process proceeds to step S206. On the other hand, when controller 30 determines that compressor input estimated value W(REF) is not smaller than compressor input value W(w) (NO), the process proceeds to step S207.

(Step S206)
The controller 30 determines that the compressor discharge temperature sensor 51 or the compressor input sensor 56 is abnormal, and notifies that the compressor discharge temperature sensor 51 or the compressor input sensor 56 is abnormal by the notification unit 36. . After that, the sensor abnormality determination process ends.

(Step S207)
The controller 30 determines whether the estimated compressor input value W(REF) is greater than the compressor input value W(w). If controller 30 determines that estimated compressor input value W(REF) is greater than compressor input value W(w) (YES), the process proceeds to step S208. On the other hand, when controller 30 determines that estimated compressor input value W(REF) is not greater than compressor input value W(w) (NO), the process proceeds to step S209.

(Step S208)
The control device 30 determines that the high pressure sensor 16 or the compressor input sensor 56 is abnormal, and notifies that the high pressure sensor 16 or the compressor input sensor 56 is abnormal by the notification unit 36 . After that, the sensor abnormality determination process ends.

(Step S209)
Control device 30 determines that each sensor is normal, and terminates the sensor abnormality determination process.

Regarding the sensor abnormality determination process described above, the abnormal sensor cannot be identified in the processes of steps S206 and S208, but the abnormal sensor can be identified by performing the sensor abnormality determination process described in the first embodiment. It can be carried out. For example, after performing the process of step S206, the sensor abnormality determination process described in the first embodiment is performed. If the process proceeds to step S106, the compressor discharge temperature sensor 51 is abnormal. It can be determined that the input sensor 56 is abnormal.

Next, processing after sensor abnormality detection of the refrigerating and air-conditioning apparatus 100 according to Embodiment 2 will be described.
Conventionally, when an abnormality occurs in the compressor discharge temperature sensor 51 and the detection value becomes low, the refrigerating and air-conditioning system 100 may malfunction. The compressor 11 is stopped even when there is an abnormality. However, in the second embodiment, the abnormal sensor can be specified, and when the compressor discharge temperature sensor 51 is abnormal, the discharge state of the compressor 11 can be estimated without using the abnormal sensor. Therefore, in Embodiment 2, it is possible to operate the compressor 11 without stopping it even after the sensor abnormality is detected.

As described above, the refrigerating and air-conditioning apparatus 100 according to Embodiment 2 includes the fifth sensor that detects the compressor input value and the frequency acquisition means that acquires the compressor frequency. Then, when the estimated compressor input value calculated based on the discharge pressure, the suction pressure, the discharge temperature, the suction temperature, and the compressor frequency is different from the compressor input value, the control device 30 performs the first It is determined that one of the sensor, the third sensor, and the fifth sensor is abnormal.

Also, the control device 30 determines that the third sensor or the fifth sensor is abnormal when the compressor input estimated value is smaller than the compressor input value.

Also, the control device 30 determines that the first sensor or the fifth sensor is abnormal when the compressor input estimated value is greater than the compressor input value.

According to the refrigerating and air-conditioning apparatus 100 according to Embodiment 2, the same effect as Embodiment 1 can be obtained.

1 refrigerant circuit, 10 outdoor unit, 11 compressor, 12 condenser, 16 high pressure sensor, 17 low pressure sensor, 20 indoor unit, 21 expansion device, 22 evaporator, 30 control device, 31 storage unit, 32 extraction unit, 33 Computing section, 34 Comparing section, 35 Judging section, 36 Reporting section, 37 Operation mode switching section, 41 Liquid pipe, 42 Gas pipe, 51 Compressor discharge temperature sensor, 54 Condenser ambient temperature sensor, 55 Compressor suction temperature sensor , 56 Compressor input sensor, 57 Compressor frequency sensor, 100 Refrigerating air conditioner.

Claims

a refrigerant circuit in which a compressor, a condenser, a throttle device, and an evaporator are connected by pipes and in which the refrigerant circulates;
a first sensor that detects the discharge pressure of the compressor or detects a temperature for calculating the discharge pressure;
a second sensor that detects the suction pressure of the compressor or detects a temperature for calculating the suction pressure;
a third sensor that detects the discharge temperature of the compressor;
a fourth sensor that detects the suction temperature of the compressor;
When the adiabatic efficiency of the compressor calculated based on the discharge pressure, the suction pressure, the discharge temperature, and the suction temperature is higher than a preset upper limit value, or the discharge temperature is higher than the discharge pressure, the A refrigerating and air-conditioning apparatus, comprising: a control device that determines that the third sensor is abnormal when the intake pressure and the discharge temperature are lower than a discharge temperature threshold calculated based on the intake temperature.
The control device is
When the adiabatic efficiency is lower than a preset lower limit value, or when the discharge pressure is lower than a high pressure threshold calculated based on the suction pressure, the discharge temperature, and the suction temperature, the first The refrigerating and air-conditioning apparatus according to claim 1, wherein the sensor is determined to be abnormal.
a fifth sensor for detecting compressor input;
a frequency acquisition means for acquiring the compressor frequency,
The control device is
When the estimated compressor input value calculated based on the discharge pressure, the suction pressure, the discharge temperature, the suction temperature, and the compressor frequency and the compressor input value are different values, the first 3. The refrigerating and air-conditioning apparatus according to claim 1, wherein it is determined that one of the sensor, the third sensor, and the fifth sensor is abnormal.
The control device is
The refrigerating and air-conditioning apparatus according to claim 3, wherein when the estimated compressor input value is smaller than the compressor input value, it is determined that the third sensor or the fifth sensor is abnormal.
The control device is
5. The refrigerating and air-conditioning apparatus according to claim 3, wherein when the estimated compressor input value is greater than the compressor input value, it is determined that the first sensor or the fifth sensor is abnormal.
The first sensor is
The refrigerating and air-conditioning system according to any one of claims 1 to 5, wherein the pressure sensor is provided on the discharge side of the compressor, or the temperature sensor is provided on a heat transfer tube that constitutes the condenser.
The second sensor is
The refrigerating and air-conditioning system according to any one of claims 1 to 6, wherein the pressure sensor is provided on the suction side of the compressor, or the temperature sensor is provided on a heat transfer tube that constitutes the evaporator.
The fourth sensor is
The refrigerating and air-conditioning system according to any one of claims 1 to 7, wherein the temperature sensor is provided on the suction side of the compressor or the temperature sensor is provided on the outlet side of the evaporator.
The control device is
If any sensor is abnormal,
The refrigerating and air-conditioning system according to any one of claims 1 to 8, wherein the compressor frequency is not increased.