Air Conditioning Equipment

Abstract

This air-conditioning device comprises a refrigerant circuit in which a compressor, a heat-source-side heat exchanger, a throttling device, and a load-side heat exchanger are connected in the stated order by piping, a non-azeotropic mixed refrigerant being sealed inside the refrigerant circuit as a refrigerant, wherein the air-conditioning device also comprises: a first pressure detection device for detecting the pressure of the refrigerant on the discharge side of the compressor, or detecting the pressure of the refrigerant on the intake side of the compressor; an outside air temperature detection device for detecting the temperature of outside air; and a control device having a refrigerant leak detection function for assessing whether a refrigerant leak has occurred, when the air-conditioning device stops, on the basis of the pressure detected by the first pressure detection device and the outside air temperature detected by the outside air temperature detection device.

Description

[Technical field]

[0001] The present disclosure relates to an air conditioning apparatus applied to a multi-air conditioner for a building or the like. [Background technology]

[0002] Conventionally, in air conditioners such as multi-air conditioners for buildings, a refrigerant circuit is formed by connecting an outdoor unit, which is a heat source unit placed outside a building, to multiple indoor units placed inside the building with refrigerant piping, and refrigerant is circulated through the refrigerant. The total length of the refrigerant piping connecting the outdoor unit and multiple indoor units can be several hundred meters, and therefore the amount of refrigerant used is very large. For this reason, in order to prevent a large amount of refrigerant from being released into the atmosphere when a refrigerant leak occurs from an air conditioner, a technology has been proposed that estimates the presence or absence of a refrigerant leak from the operating state of the air conditioner (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2009 / 157200 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology disclosed in Patent Document 1 requires that the operating mode be set to cooling operation mode, and there is an issue that it is not possible to determine whether a refrigerant leak has occurred during intermediate periods when the air conditioning system is not in operation, or in winter when the system is in heating operation.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an air conditioning apparatus that can detect the occurrence of a refrigerant leak from the air conditioning apparatus regardless of the operating status of the air conditioning apparatus. [Means for solving the problem]

[0006] The air conditioner according to the present disclosure is an air conditioner including a refrigerant circuit in which a compressor, a heat source side heat exchanger, a throttling device, and a load side heat exchanger are connected in this order by piping, and in which a non-azeotropic refrigerant mixture is sealed as the refrigerant in the refrigerant circuit, and includes a first pressure detection device that detects the pressure of the refrigerant on the discharge side of the compressor or the pressure of the refrigerant on the suction side of the compressor, an outdoor air temperature detection device that detects the outdoor air temperature, and a control device having a refrigerant leakage detection function that determines the presence or absence of a refrigerant leak based on the pressure detected by the first pressure detection device and the outdoor air temperature detected by the outdoor air temperature detection device when the air conditioner is stopped. Regarding the refrigerant leakage detection function, the control device determines whether or not there is a refrigerant leakage if the outdoor air temperature detected by the outdoor air temperature detection device is stable after a preset first time has elapsed since the air conditioning device was stopped. It is something. Effect of the Invention

[0007] According to the air conditioner of the present disclosure, when the air conditioner is stopped, the presence or absence of a refrigerant leak is determined based on the pressure detected by the first pressure detection device and the outdoor air temperature detected by the outdoor air temperature detection device. Therefore, refrigerant leaks can be detected throughout the year regardless of the time of year, and the occurrence of a refrigerant leak from the air conditioner can be detected regardless of the operating status of the air conditioner. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing an example of the configuration of an air conditioning device according to an embodiment. [Diagram 2] 1 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioning device according to an embodiment. [Diagram 3] FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of the air conditioning apparatus according to the embodiment. [Figure 4] FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the air conditioner according to the embodiment. [Diagram 5] 5 is a flowchart showing the operation of a refrigerant leakage detection function of the air conditioning apparatus according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 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.

[0010] Embodiment 1 FIG. 1 is a schematic diagram showing an example of the configuration of an air conditioning apparatus 100 according to an embodiment. The configuration of the air conditioning apparatus 100 according to the first embodiment will be described below with reference to FIG.

[0011] The air conditioner 100 according to the embodiment performs air conditioning using a refrigeration cycle by circulating a non-azeotropic mixed refrigerant consisting of multiple refrigerants with different boiling points, for example, R454B refrigerant, which is a mixture of R32 refrigerant and R1234yf refrigerant at a mass ratio of 68.9 [wt%] and 31.1 [wt%], in a refrigerant circuit (see FIG. 2 described later). In addition, the air conditioner 100 can select an all-cooling operation mode in which all indoor units operating perform cooling or an all-heating operation mode in which all indoor units perform heating, as in a multi-air conditioner for a building, for example. As shown in FIG. 1, the air conditioner 100 includes one outdoor unit 1 and two indoor units 2a and 2b, and the outdoor unit 1 and the indoor units 2a and 2b are connected by a refrigerant main pipe 3 and refrigerant branch pipes 4a and 4b arranged in a ceiling space 61. In addition, the indoor units 2a and 2b are installed in air-conditioned spaces 60a and 60b, respectively. In the embodiment, as shown in FIG. 1, there is one outdoor unit 1 and two indoor units 2a, 2b, but this is not limited to this, and there may be two or more outdoor units 1, and one or three or more indoor units 2a, 2b.

[0012] FIG. 2 is a refrigerant circuit diagram showing an example of an air conditioning apparatus 100 according to an embodiment. The air-conditioning apparatus 100 includes a refrigerant circuit through which a refrigerant flows, as shown in Fig. 2. The refrigerant circuit includes a compressor 10, a refrigerant flow switching device 11, a heat source side heat exchanger 12, expansion devices 41a, 41b, load side heat exchangers 40a, 40b, and an accumulator 13, which are connected in this order by piping including a main refrigerant pipe 3, refrigerant branch pipes 4a, 4b, and a refrigerant pipe 5.

[0013] [Outdoor unit 1] The outdoor unit 1 includes a compressor 10, a refrigerant flow switching device 11, a heat source side heat exchanger 12, and an accumulator 13. A heat source side blower 14 constituted by, for example, a fan is provided near the heat source side heat exchanger 12, and the heat source side blower 14 blows air to the heat source side heat exchanger 12. The compressor 10, the refrigerant flow switching device 11, the heat source side heat exchanger 12, and the accumulator 13 are connected by refrigerant piping 5.

[0014] The compressor 10 sucks in a low-temperature, low-pressure refrigerant and compresses it to a high-temperature, high-pressure state, and may be, for example, a capacity-controllable inverter compressor, etc. The refrigerant flow switching device 11 is, for example, a four-way valve, and switches the refrigerant flow between a cooling operation mode and a heating operation mode.

[0015] The heat source side heat exchanger 12 functions as a condenser in the cooling operation mode and as an evaporator in the heating operation mode, and exchanges heat between the air supplied from the heat source side blower 14 and the refrigerant.

[0016] The accumulator 13 is provided on the suction side of the compressor 10, and is intended to store excess refrigerant that occurs due to differences in operating conditions between the cooling operation mode and the heating operation mode, or excess refrigerant due to transient changes in operation.

[0017] The outdoor unit 1 also includes a discharge pressure detection device 20 and a suction pressure detection device 21. The discharge pressure detection device 20 is provided in the refrigerant piping 5 connecting the discharge side of the compressor 10 and the refrigerant flow path switching device 11, and detects the pressure of the high-temperature, high-pressure refrigerant on the discharge side of the compressor 10. The suction pressure detection device 21 is provided in the refrigerant piping 5 connecting the refrigerant flow path switching device 11 and the suction side of the compressor 10, and detects the pressure of the low-temperature, low-pressure refrigerant on the suction side of the compressor 10. The discharge pressure detection device 20 and the suction pressure detection device 21 are, for example, pressure sensors.

[0018] The outdoor unit 1 also includes an outdoor air temperature detection device 22 and a first temperature detection device 23. The outdoor air temperature detection device 22 is provided in an air intake section (not shown) of the outdoor unit 1, and detects the air temperature (hereinafter referred to as the outdoor air temperature) at the location where the outdoor unit 1 is installed. The first temperature detection device 23 is provided in the refrigerant piping 5 connecting the discharge side of the compressor 10 and the refrigerant flow switching device 11, and detects the temperature of the high-temperature, high-pressure refrigerant on the discharge side of the compressor 10 (hereinafter referred to as the discharge temperature). The outdoor air temperature detection device 22 and the first temperature detection device 23 are, for example, thermistors.

[0019] [Indoor units 2a, 2b] The indoor units 2a and 2b are respectively equipped with load-side heat exchangers 40a and 40b and throttling devices 41a and 41b. In addition, load-side blowers 42a and 42b, which are composed of, for example, fans, are provided near the load-side heat exchangers 40a and 40b, and the load-side blowers 42a and 42b blow air to the load-side heat exchangers 40a and 40b. The indoor units 2a and 2b are connected to the outdoor unit 1 via the refrigerant main pipe 3, so that the refrigerant flows in and out. The load-side heat exchangers 40a and 40b exchange heat between the air supplied from the load-side blowers 42a and 42b and the refrigerant, and generate heating air or cooling air to be supplied to the indoor space. In addition, the throttling devices 41a and 41b have the function of a pressure reducing valve or an expansion valve, and reduce the pressure of the refrigerant to expand it, and may be configured as a valve whose opening degree can be variably controlled, such as an electronic expansion valve.

[0020] The indoor units 2a and 2b are respectively provided with second temperature detectors 50a and 50b, third temperature detectors 51a and 51b, and fourth temperature detectors 52a and 52b. The second temperature detectors 50a and 50b are provided in the refrigerant branch pipes 4a and 4b connecting the throttling devices 41a and 41b and the load side heat exchangers 40a and 40b, and detect the temperature of the refrigerant flowing into the load side heat exchangers 40a and 40b in the cooling operation mode. The third temperature detectors 51a and 51b are provided in the refrigerant branch pipes 4a and 4b on the opposite side of the throttling devices 41a and 41b with respect to the load side heat exchangers 40a and 40b, and detect the temperature of the refrigerant flowing out of the load side heat exchangers 40a and 40b in the cooling operation mode. The fourth temperature detectors 52a, 52b are provided in the air intakes (not shown) of the load-side heat exchangers 40a, 40b to detect the indoor air temperature. The second temperature detectors 50a, 50b, the third temperature detectors 51a, 51b, and the fourth temperature detectors 52a, 52b are, for example, thermistors.

[0021] In the following description, the indoor units 2a and 2b, the load-side heat exchangers 40a and 40b, the throttling devices 41a and 41b, and the load-side blowers 42a and 42b are collectively referred to as the indoor unit 2, the load-side heat exchanger 40, the throttling device 41, and the load-side blower 42, respectively. The second temperature detection devices 50a and 50b, the third temperature detection devices 51a and 51b, and the fourth temperature detection devices 52a and 52b are collectively referred to as the second temperature detection device 50, the third temperature detection device 51, and the fourth temperature detection device 52, respectively. Either the discharge pressure detection device 20 or the suction pressure detection device 21 is also referred to as the first pressure detection device. The discharge pressure detection device 20 and the suction pressure detection device 21 are collectively referred to as the pressure detection device.

[0022] The air conditioner 100 also includes a control device 30 configured with a microcomputer and the like. The control device 30 controls the frequency of the compressor 10, the rotation speed of the heat source side blower 14 of the heat source side heat exchanger 12 (including ON / OFF of the heat source side blower 14), the switching of the refrigerant flow switching device 11, the opening degree of the throttling device 41, and the like based on the detection values ​​of the various detection devices and instructions from a remote control, and executes each operation mode described below. Note that in the embodiment, as shown in FIG. 2, an example in which the control device 30 is provided in the outdoor unit 1 is shown, but this is not limiting. The control device 30 may be provided in the indoor unit 2, or in both the outdoor unit 1 and the indoor unit 2.

[0023] [Cooling operation mode] Fig. 3 is a refrigerant circuit diagram showing the flow of refrigerant in a cooling operation mode of the air conditioner 100 according to the embodiment. Note that in Fig. 3, the direction of refrigerant flow is indicated by solid arrows. Hereinafter, with reference to FIG. 3, the cooling operation mode of the air conditioner 100 according to the embodiment will be described taking as an example a case in which a cooling load is generated in the load-side heat exchangers 40a, 40b.

[0024] In the cooling operation mode, the refrigerant flow switching device 11 is switched so that the refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12. Then, the low temperature, low pressure refrigerant is compressed by the compressor 10 and discharged as a high temperature, high pressure gas refrigerant. The high temperature, high pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 via the refrigerant flow switching device 11. The high temperature, high pressure gas refrigerant that flows into the heat source side heat exchanger 12 condenses while releasing heat to the outdoor air, becoming a high pressure liquid refrigerant. Then, the high pressure liquid refrigerant that flows out of the heat source side heat exchanger 12 flows out of the outdoor unit 1, passes through the refrigerant main pipe 3 and the refrigerant branch pipes 4a, 4b, and flows into the indoor units 2a, 2b.

[0025] The high-pressure liquid refrigerant flowing into the indoor units 2a, 2b is decompressed to a low-temperature, low-pressure two-phase refrigerant by the throttling devices 41a, 41b, and then flows into the load-side heat exchangers 40a, 40b acting as evaporators, where it absorbs heat from the indoor air to cool it and become a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant flowing out of the load-side heat exchangers 40a, 40b passes through the refrigerant branch pipes 4a, 4b and the main refrigerant pipe 3, and flows into the outdoor unit 1. The refrigerant flowing into the outdoor unit 1 passes through the refrigerant flow switching device 11 and the accumulator 13, and is sucked into the compressor 10.

[0026] Here, the opening degree of the expansion devices 41a, 41b is controlled by the control device 30 so that the superheat (degree of superheat) obtained as the difference between the temperature detected by the second temperature detection devices 50a, 50b and the temperature detected by the third temperature detection devices 51a, 51b is kept constant. This allows the device to exert its capacity according to the thermal load in the room, and allows efficient operation.

[0027] [Heating operation mode] Fig. 4 is a refrigerant circuit diagram showing the flow of refrigerant in the heating operation mode of the air conditioner 100, with the direction of refrigerant flow indicated by solid arrows. Note that in Fig. 4, the direction of refrigerant flow is indicated by solid arrows. Hereinafter, with reference to FIG. 4, the heating operation of the air conditioner 100 according to the embodiment will be described taking as an example a case in which a heating load is generated in the load-side heat exchangers 40a, 40b.

[0028] In the heating operation mode, the refrigerant flow switching device 11 is switched so that the refrigerant discharged from the compressor 10 flows into the load side heat exchangers 40a, 40b. Then, the low-temperature, low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 passes through the refrigerant main pipe 3 and the refrigerant branch pipes 4a, 4b via the refrigerant flow switching device 11 and flows into the indoor units 2a, 2b. The high-temperature, high-pressure gas refrigerant that flows into the indoor units 2a, 2b dissipates heat to the indoor air in the load side heat exchangers 40a, 40b, becomes a high-pressure liquid refrigerant, and flows into the throttling devices 41a, 41b. Then, after being decompressed into a low-temperature, low-pressure two-phase refrigerant by the throttling devices 41a, 41b, it flows out of the indoor units 2a, 2b, passes through the refrigerant branch pipes 4a, 4b and the refrigerant main pipe 3, and flows into the outdoor unit 1.

[0029] The low-temperature, low-pressure two-phase refrigerant that has flowed into the outdoor unit 1 flows into the heat source-side heat exchanger 12, and becomes a low-temperature, low-pressure gas refrigerant by absorbing heat from the outdoor air. The low-temperature, low-pressure gas refrigerant that has flowed out of the heat source-side heat exchanger 12 passes through the refrigerant flow switching device 11 and the accumulator 13, and is sucked into the compressor 10.

[0030] Here, the opening degree of the throttling devices 41a and 41b is controlled by the control device 30 so that the subcooling (degree of supercooling) obtained as the difference between the saturated liquid temperature of the refrigerant calculated from the pressure detected by the discharge pressure detection device 20 and the temperature detected by the second temperature detection devices 50a and 50b is kept constant. This allows the device to demonstrate its capacity according to the thermal load in the room, and allows efficient operation.

[0031] [Refrigerant leak detection function] Next, the refrigerant leakage detection function will be described. The refrigerant leakage detection function is one of the functions of the control device 30, and is a function that detects the presence or absence of a refrigerant leakage based on the detection value of the pressure detection device mounted on the outdoor unit 1 and the detection value of the outdoor air temperature detection device 22 when the air conditioning apparatus 100 is in a stopped state.

[0032] FIG. 5 is a flowchart showing the operation of the refrigerant leakage detection function of the air conditioning apparatus 100 according to the embodiment. Hereinafter, the operation of the refrigerant leakage detection function of the air conditioning apparatus 100 according to the embodiment will be described with reference to FIG.

[0033] (Step S1) The control device 30 determines whether the air conditioning device 100 is in a stopped state. Here, the air conditioning device 100 being in a stopped state means a state in which the compressor 10 is stopped. If the control device 30 determines that the air conditioning device 100 is in a stopped state (YES), the process proceeds to step S2. On the other hand, if the control device 30 determines that the air conditioning device 100 is not in a stopped state (NO), the process repeats step S1.

[0034] (Step S2) The control device 30 judges whether a predetermined time or more (hereinafter also referred to as the preset first time) has elapsed since the air conditioning device 100 was in a stopped state. Here, the control device 30 has a timer function for measuring time. If the control device 30 judges that a predetermined time or more has elapsed since the air conditioning device 100 was in a stopped state (YES), the process proceeds to step S3. On the other hand, if the control device 30 judges that the predetermined time or more has not elapsed since the air conditioning device 100 was in a stopped state (NO), the process returns to step S1. Note that, in the embodiment, the control device 30 has a timer function, but is not limited to this, and for example, a real-time clock or the like may be provided outside the control device 30.

[0035] (Step S3) The control device 30 determines whether the outside air temperature detected by the outside air temperature detection device 22 is stable. Here, the determination of whether the outside air temperature detected by the outside air temperature detection device 22 is stable is made, for example, based on whether the outside air temperature detected by the outside air temperature detection device 22 falls within a predetermined range for a predetermined time. If the control device 30 determines that the outside air temperature detected by the outside air temperature detection device 22 is stable (YES), the process proceeds to step S4. On the other hand, if the control device 30 determines that the outside air temperature detected by the outside air temperature detection device 22 is not stable (NO), the process returns to step S1.

[0036] (Step S4) The control device 30 calculates the saturation temperature of the refrigerant from the detection value of the discharge pressure detection device 20. In a non-azeotropic refrigerant mixture, the saturated vapor temperature and the saturated liquid temperature at the same pressure are different, so it is necessary to clearly define which saturation temperature to use, or whether to use the average value of these two saturation temperatures. In the stop-time refrigerant leakage function according to the embodiment, any of the saturated vapor temperature, the saturated liquid temperature, and the average value of these two saturation temperatures may be used. In the above, the discharge pressure detection device 20 is used to calculate the saturation temperature of the refrigerant, but the suction pressure detection device 21 may be used instead of the discharge pressure detection device 20 to calculate the saturation temperature of the refrigerant.

[0037] (Step S5) The control device 30 determines whether the difference between the saturation temperature of the refrigerant calculated in step S4 and the outside air temperature detected by the outside air temperature detection device 22 is equal to or greater than a predetermined value. If the control device 30 determines that the difference between the saturation temperature of the refrigerant and the outside air temperature is equal to or greater than the predetermined value (YES), the process proceeds to step S6. On the other hand, if the control device 30 determines that the difference between the saturation temperature of the refrigerant and the outside air temperature is not equal to or greater than the predetermined value (NO), the process returns to step S1.

[0038] (Step S6) The control device 30 determines that a refrigerant leak has occurred in the air conditioning device 100, and the process ends. After that, the control device 30 executes, for example, a refrigerant leak notification function, which will be described later.

[0039] [Principle of refrigerant leak detection function] Next, the principle of the refrigerant leakage detection function will be described. First, the refrigerant filled in the refrigerant circuit of the air conditioner 100 according to the embodiment is a non-azeotropic refrigerant mixture. A non-azeotropic refrigerant mixture is composed of multiple types of refrigerants with different boiling points. For example, the non-azeotropic refrigerant mixture R454B refrigerant is a mixture of R32 refrigerant and R1234yf refrigerant. The boiling point of R32 refrigerant at atmospheric pressure is -57.1 [°C], and the boiling point of R1234yf refrigerant at atmospheric pressure is -29.4 [°C]. If there is a difference in the boiling points of the refrigerants that make up the non-azeotropic refrigerant mixture, when a refrigerant leak occurs from the air conditioner 100, more R32 refrigerant with a lower boiling point tends to be released outside the system.

[0040] For this reason, the ratio of refrigerant that makes up the non-azeotropic refrigerant mixture sealed in the refrigerant circuit of the air conditioning device 100 will differ between when there is a refrigerant leak and when there is no refrigerant leak, and the physical property values ​​of the non-azeotropic refrigerant mixture present in the air conditioning device 100 will change depending on whether there is a refrigerant leak. The refrigerant leak detection function utilizes this change in the physical property values ​​of the non-azeotropic refrigerant mixture caused by a refrigerant leak.

[0041] The principle of the refrigerant leakage detection function will be described in more detail below. Generally, when the air conditioning apparatus 100 is stopped, a thermal balance is achieved between the refrigerant in the refrigerant circuit and the outside air where the outdoor unit 1 is installed, so the saturation temperature calculated from the refrigerant pressure in the refrigerant circuit is equal to the outside air temperature.

[0042] However, if a refrigerant leak occurs, the physical properties of the non-azeotropic refrigerant mixture change as described above, and so the pressure in the refrigerant circuit when the air conditioning device 100 is stopped at a certain outside temperature changes depending on whether or not there is a refrigerant leak. Therefore, the principle of the refrigerant leak detection function is to detect the presence or absence of a refrigerant leak by detecting the difference in pressure in the refrigerant circuit when the air conditioning device 100 is stopped.

[0043] Taking the case of R454B refrigerant as an example, when no refrigerant leakage occurs, R32 refrigerant and R1234yf refrigerant are present in the refrigerant circuit of the air conditioner 100 in mass ratios of 68.9 [wt%] and 31.1 [wt%]. On the other hand, when a refrigerant leakage occurs, if the composition change due to the refrigerant leakage is α (>0), R32 refrigerant and R1234yf refrigerant are present in the refrigerant circuit of the air conditioner 100 in mass ratios of (68.9-α) [wt%] and (31.1+α) [wt%]. In other words, when a refrigerant leakage occurs, the composition of R32 refrigerant, which has a low boiling point, becomes less.

[0044] When the composition of the refrigerant changes due to a refrigerant leak, the physical properties of the non-azeotropic refrigerant mixture also change, for example, the saturation pressure at a certain temperature also changes.

[0045] For example, when the outdoor air temperature is 35°C, if there is no refrigerant leakage, and the air conditioner 100 is stopped, the outdoor air and the outdoor unit 1 are in thermal balance, so the pressure in the refrigerant circuit is 2.0 MPaA, which is the saturation pressure of R454B refrigerant at 35°C. On the other hand, when there is a refrigerant leakage, the outdoor air and the outdoor unit 1 at the same temperature (35°C) are in thermal balance, but the R32 refrigerant is less by the composition change α and the R1234yf refrigerant is more by the composition change α from the composition of the R454B refrigerant, so the pressure in the refrigerant circuit is different even at the same outdoor air temperature of 35°C. In this example, the composition of the R32 refrigerant is less, so the pressure is lower than 2.0 MPaA when there is no refrigerant leakage.

[0046] The control device 30 has the relationship between the pressure and saturation temperature for the filling composition of the non-azeotropic refrigerant in the form of a table or an approximate formula, and can determine that a refrigerant leak has occurred if the saturation temperature calculated from the pressure detected by the discharge pressure detection device 20 or the suction pressure detection device 21 does not match the outside air temperature.

[0047] That is, in steps S1 to S3 shown in FIG. 5, it is determined whether the outdoor air and the outdoor unit 1 are thermally balanced, and in steps S4 to S6, the difference between the saturation temperature caused by the above-mentioned refrigerant leak and the outdoor air temperature is calculated to detect the occurrence of a refrigerant leak.

[0048] In addition, since the amount of drop in saturation pressure when a refrigerant leak occurs varies depending on factors such as the type of non-azeotropic refrigerant used in air conditioning device 100, the size of the refrigerant circuit of air conditioning device 100, and how much refrigerant has leaked outside the system, it is difficult to determine the specified value for step S5 shown in Figure 5 as a constant value.

[0049] If the predetermined value in step S5 in FIG. 5, which determines whether or not a refrigerant leak has occurred, is set to a small value, even a small amount of refrigerant leakage can be detected, but if the thermal balance between the outdoor air and the outdoor unit 1 is insufficient, or if there is a measurement error in the pressure detection device or the outdoor air temperature detection device 22, the refrigerant leakage determination may be erroneous. On the other hand, if the predetermined value in step S5 is set to a large value, the risk of erroneous refrigerant leakage determination is reduced, but there is also a disadvantage that the presence of a refrigerant leakage cannot be determined unless the amount of refrigerant leakage from the air conditioning device 100 becomes large. For this reason, the predetermined value in step S5 needs to be changed depending on the type of refrigerant used, the size of the refrigerant circuit of the air conditioning device 100, and how much refrigerant has leaked outside the system. In addition, since the predetermined value in step S5 is also affected by the installation state of the air conditioning device 100, it is recommended that it be adjusted on-site at the stage when the installation work is completed.

[0050] Here, the predetermined value in step S5 will be supplemented by taking the case of R454B refrigerant as an example. There is R454C refrigerant, which has the same composition as R454B refrigerant, and R454C refrigerant is a mixture of R32 refrigerant and R1234yf refrigerant in a mass ratio of 21.5 [wt%] and 78.5 [wt%]. For example, when the outside air temperature is 7 [°C], the saturated vapor pressure of R454B refrigerant is 0.91 [MPaA], but the saturated vapor pressure of R454C refrigerant at the same outside air temperature of 7 [°C] is 0.57 [MPaA]. This pressure of 0.57 [MPaA] corresponds to a saturation temperature of -8.1 [°C] for R454B refrigerant.

[0051] That is, for R454B refrigerant, when the air conditioning apparatus 100 is stopped with an outside air temperature of 7°C, if there is no refrigerant leakage, the saturation temperature of the refrigerant will be 7°C from the detection value of the discharge pressure detection device 20. On the other hand, if a refrigerant leakage occurs, R32 refrigerant is released into the atmosphere before R1234yf refrigerant, and the refrigerant composition is equivalent to that of R454C refrigerant, the saturation temperature of the refrigerant will be -8.1°C from the detection value of the discharge pressure detection device 20. Therefore, in this embodiment, a refrigerant leakage can be sufficiently detected even if the predetermined value in step S5 is set to 1°C.

[0052] To improve the accuracy of the refrigerant leak detection function, it is preferable to use an outside air temperature detection device 22 with higher detection accuracy than the other temperature detection devices. Similarly, it is preferable to use at least one of the discharge pressure detection device 20 and the suction pressure detection device 21 with higher detection accuracy as the pressure detection device, and use the detection value to determine whether there is a refrigerant leak.

[0053] 5, which is a necessary condition for the refrigerant leak detection function, the predetermined time in step S2 should be the time until the detection value of the discharge pressure detection device 20 and the detection value of the suction pressure detection device 21 mounted on the outdoor unit 1 become the same. Also, since the accuracy of refrigerant leak detection is improved if the detection value of the outdoor air temperature detection device 22 in step S3 is stable, it is preferable to determine whether the outdoor air temperature detected by the outdoor air temperature detection device 22 is stable when the change in outdoor air temperature per hour is 1°C or less, for example.

[0054] Even if a single-component refrigerant is sealed in the refrigerant circuit of the air conditioner 100, the pressure in the refrigerant circuit will drop if a refrigerant leak occurs, and it may be possible to determine the refrigerant leak from the detection value of the pressure detection device, but in large-scale air conditioners such as a multi-system for buildings equipped with an accumulator 13, excess refrigerant exists in the refrigerant circuit in liquid phase, and when the pressure in the refrigerant circuit is about to drop due to a refrigerant leak, the excess refrigerant evaporates to become gas refrigerant, suppressing the pressure drop in the refrigerant circuit. Therefore, the pressure in the refrigerant circuit is unlikely to change until all of the excess refrigerant in liquid phase has evaporated, so it is difficult to detect a refrigerant leak using the refrigerant pressure when a single-component refrigerant is used in an air conditioner equipped with an accumulator 13.

[0055] In contrast, when a non-azeotropic refrigerant mixture is sealed in the refrigerant circuit of the air conditioning device 100, when the accumulator 13 is installed, the pressure in the refrigerant circuit is less likely to decrease due to evaporation of excess liquid phase refrigerant, as in the case of a single component refrigerant. However, since the non-azeotropic refrigerant mixture has the characteristic that refrigerant with a low boiling point leaks out of the system in greater amounts, fluctuations in the refrigerant composition (changes in physical properties) occur, and refrigerant leaks can be detected even in small amounts.

[0056] The refrigerant leakage detection function in this embodiment is based on the principle of utilizing the boiling point difference of non-azeotropic refrigerants. Therefore, if the air conditioning device 100 uses a non-azeotropic mixed refrigerant, the accumulator 13 is not an essential component. Even if the accumulator 13 is not present, a refrigerant leakage can be detected by the operation shown in FIG. 5.

[0057] The control device 30 also has a daily inspection function that executes the refrigerant leak detection function at predetermined times (hereinafter also referred to as the preset second time). This daily inspection function makes it possible to perform a refrigerant leak determination during intermediate periods such as spring or fall, or at night, when the air conditioning device 100 is not in operation. This makes it possible to check for refrigerant leaks every day or every few days, enabling early detection of refrigerant leaks. Furthermore, refrigerant leaks can be detected no matter where they occur.

[0058] Furthermore, the control device 30 has a refrigerant leak notification function that notifies the occurrence of a refrigerant leak when it executes the refrigerant leak detection function and determines that there is a refrigerant leak. As a means for notifying the occurrence of a refrigerant leak, for example, a buzzer or the like is sounded, or, if a centralized management device or the like is connected to the air conditioning device 100, an alert is issued to the centralized management device that a refrigerant leak has been detected, prompting an inspection of the air conditioning device 100. In this way, the facility manager can be notified of the occurrence of a refrigerant leak at an early stage, and appropriate measures such as equipment repair can be taken promptly.

[0059] Furthermore, in conventional air conditioning systems that use flammable refrigerants, a refrigerant leak detection device is typically installed inside the indoor unit or in the air-conditioned space in which the indoor unit is installed to ensure safety within the room in the event of a refrigerant leak. However, there is an issue that refrigerant leaks cannot be detected in spaces where a refrigerant leak detection device is not installed, such as above the ceiling or in rooms with a large floor area.

[0060] To address this issue, the refrigerant used must be a non-azeotropic refrigerant mixture, but by using the refrigerant leak detection function of this embodiment, it is possible to detect refrigerant leaks from locations where there is no refrigerant leak detection device, thereby improving safety inside the room.

[0061] Furthermore, if the air conditioning apparatus 100 is equipped with safety devices such as an alarm device, a ventilation device, and a shutoff device that are specified in international standards such as ISO5149 or IEC60335-2-40, safety inside the room can be further improved by configuring the system to activate the above-mentioned safety devices when the refrigerant leak detection function of this embodiment determines that there is a refrigerant leak.

[0062] In the air conditioning apparatus 100 according to this embodiment, all of the indoor units 2a, 2b are in the same operation, i.e., in only one of the cooling operation mode and the heating operation mode, as an example. However, this is not limited to this, and each of the indoor units 2a, 2b may be in a different operation, i.e., the cooling operation mode and the heating operation mode may be performed simultaneously.

[0063] Also, although the present embodiment has been described taking the example of a case where there is one outdoor unit 1, the number of outdoor units 1 is not limited to one. The operation of the refrigerant leakage detection function shown in Fig. 5 requires two detection devices, the pressure detection device and the outdoor air temperature detection device 22, as necessary components of the outdoor unit 1, and there are no restrictions on the other components of the air conditioner 100, so in the case of a large air conditioning system made up of multiple outdoor units 1, the operation of the refrigerant leakage detection function may be performed for each outdoor unit 1, or one of the multiple outdoor units 1 may be set as a representative, and the representative outdoor unit 1 may perform the operation of the refrigerant leakage detection function.

[0064] Further, in the air conditioning apparatus 100 according to this embodiment, an example has been described in which one compressor 10 is provided in the outdoor unit 1, but this is not limited thereto, and two or more compressors 10 may be provided in the outdoor unit 1.

[0065] As described above, the air conditioning apparatus 100 according to the embodiment is equipped with a refrigerant circuit in which the compressor 10, the heat source side heat exchanger 12, the throttling device 41, and the load side heat exchanger 40 are connected in order by piping, and a non-azeotropic refrigerant mixture is sealed in the refrigerant circuit. The air conditioning apparatus 100 is equipped with a first pressure detection device that detects the pressure of the refrigerant on the discharge side of the compressor 10 or detects the pressure of the refrigerant on the suction side of the compressor 10, an outdoor air temperature detection device 22 that detects the outdoor air temperature, and a control device 30 having a refrigerant leak detection function that determines whether or not there is a refrigerant leak based on the pressure detected by the first pressure detection device and the outdoor air temperature detected by the outdoor air temperature detection device 22 when the air conditioning apparatus 100 is stopped.

[0066] According to the air conditioning apparatus 100 according to the embodiment, when the air conditioning apparatus 100 is stopped, a determination is made as to whether or not there is a refrigerant leak based on the pressure detected by the first pressure detection device and the outdoor air temperature detected by the outdoor air temperature detection device 22. As a result, refrigerant leaks can be detected throughout the year regardless of the time of year, and the occurrence of a refrigerant leak from the air conditioning apparatus can be detected regardless of the operating status of the air conditioning apparatus.

[0067] Furthermore, some conventional technologies aim to ensure the safety of the air-conditioned space in which the indoor unit is installed, and do not target refrigerant leaks in large spaces where the refrigerant concentration in the air-conditioned space is not high even if a refrigerant leak occurs, or refrigerant leaks from refrigerant piping in non-air-conditioned spaces such as above the ceiling. However, the air conditioning device 100 according to the embodiment is able to detect a refrigerant leak no matter where the leak occurs.

[0068] In addition, in the prior art, there is an air conditioning device that has multiple shutoff valves and identifies the location of the refrigerant leak by detecting a pressure drop in the section closed by the shutoff valves. However, the air conditioning device 100 according to the embodiment does not require multiple shutoff valves, and therefore manufacturing costs can be reduced.

[0069] Moreover, the air conditioner 100 according to the embodiment is provided with an accumulator 13 on the suction side of the compressor 10.

[0070] According to the air conditioning device 100 of this embodiment, an accumulator 13 is provided on the suction side of the compressor 10, so that fluctuations in the refrigerant composition (changes in physical properties) occur, making it possible to detect refrigerant leaks even in small amounts.

[0071] Moreover, the air conditioning apparatus 100 according to the embodiment is provided with a temperature detection device in addition to the outdoor air temperature detection device 22, and the outdoor air temperature detection device 22 has higher detection accuracy than the temperature detection device.

[0072] According to the air conditioning apparatus 100 according to the embodiment, it is possible to improve the detection accuracy of the refrigerant leakage detection function.

[0073] Moreover, the air conditioning apparatus 100 according to the embodiment is provided with a pressure detection device in addition to the first pressure detection device, and the first pressure detection device has higher detection accuracy than the pressure detection device.

[0074] According to the air conditioning apparatus 100 according to the embodiment, it is possible to improve the detection accuracy of the refrigerant leakage detection function.

[0075] Furthermore, in the air conditioning apparatus 100 according to the embodiment, the control device 30 has a daily inspection function that executes a refrigerant leakage detection function at preset second time intervals.

[0076] According to the air conditioning apparatus 100 of the embodiment, this daily inspection function makes it possible to judge for refrigerant leaks even during intermediate periods such as spring or autumn when the air conditioning apparatus 100 is not operated, or at night. This makes it possible to check for refrigerant leaks every day or every few days, enabling early detection of refrigerant leaks. Furthermore, refrigerant leaks can be detected no matter where they occur.

[0077] Furthermore, in the air conditioning apparatus 100 according to the embodiment, the control device 30 executes a refrigerant leakage detection function, and when it determines that a refrigerant leak has occurred, reports the occurrence of a refrigerant leak.

[0078] According to the air conditioning device 100 of the embodiment, when it is determined that a refrigerant leak has occurred, the occurrence of the refrigerant leak is reported, making it possible to notify the facility manager of the refrigerant leak at an early stage and enabling appropriate measures, such as repairing the equipment, to be taken promptly. [Explanation of symbols]

[0079] 1 outdoor unit, 2, 2a, 2b indoor unit, 3 refrigerant main pipe, 4a, 4b refrigerant branch pipe, 5 refrigerant piping, 10 compressor, 11 refrigerant flow switching device, 12 heat source side heat exchanger, 13 accumulator, 14 heat source side blower, 20 discharge pressure detection device, 21 suction pressure detection device, 22 outdoor air temperature detection device, 23 first temperature detection device, 30 control device, 40, 40a, 40b load side heat exchanger, 41, 41a, 41b throttling device, 42, 42a, 42b load side blower, 50, 50a, 50b second temperature detection device, 51, 51a, 51b third temperature detection device, 52, 52a, 52b fourth temperature detection device, 60a, 60b air-conditioned space, 61 attic space, 100 air conditioning device.

Claims

1. An air-conditioning apparatus comprising a refrigerant circuit in which a compressor, a heat source-side heat exchanger, a throttling device, and a load-side heat exchanger are connected in sequence by piping, and a non-azeotropic refrigerant mixture is sealed in the refrigerant circuit, a first pressure detection device that detects a pressure of a refrigerant on a discharge side of the compressor or detects a pressure of a refrigerant on a suction side of the compressor; An outside air temperature detection device for detecting an outside air temperature; a control device having a refrigerant leakage detection function that determines whether or not a refrigerant leakage exists based on the pressure detected by the first pressure detection device and the outside air temperature detected by the outside air temperature detection device when the air conditioning device is stopped; Regarding the refrigerant leakage detection function, The control device includes: When a preset first time has elapsed since the air conditioner was stopped and the outdoor air temperature detected by the outdoor air temperature detection device is stable, a determination is made as to whether or not there is a refrigerant leak. Air conditioning units.

2. Regarding the refrigerant leakage detection function, The control device includes: The saturation temperature of the refrigerant calculated from the pressure detected by the first pressure detection device is compared with the outside air temperature detected by the outside air temperature detection device to determine whether or not there is a refrigerant leak. The air conditioning apparatus according to claim 1.

3. An accumulator is provided on the intake side of the compressor.

3. An air conditioning apparatus according to claim 1 or 2.

4. In addition to the outside air temperature detection device, a temperature detection device is provided, The outside air temperature detection device has higher detection accuracy than the temperature detection device. The air conditioning apparatus according to any one of claims 1 to 3.

5. A pressure detection device is provided in addition to the first pressure detection device, The first pressure detection device has a higher detection accuracy than the second pressure detection device. The air conditioning apparatus according to any one of claims 1 to 4.

6. The control device includes: A daily inspection function is provided for executing the refrigerant leakage detection function at preset second time intervals. The air conditioning apparatus according to any one of claims 1 to 5.

7. The control device includes: The refrigerant leakage detection function is executed, and when it is determined that a refrigerant leakage exists, the occurrence of the refrigerant leakage is notified. The air conditioner according to any one of claims 1 to 6.

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