Air conditioner

Abstract

This air conditioner using a flammable refrigerant is provided with: a detection unit (12) that detects within a space to be air-conditioned, which is a space to be air-conditioned; a calculation unit (14) that calculates the volume within the space to be air-conditioned on the basis of the detection result obtained by the detection unit (12); a comparison unit (15) that compares a calculated volume within the space to be air-conditioned, which is the volume calculated by the calculation unit (14), with a set volume, which is a volume preset for the space to be air-conditioned; and a countermeasure processing unit (16) that performs a predetermined countermeasure process when, as a result of the comparison by the comparison unit (15), the calculated volume is smaller than the set volume.

Description

Air conditioner

[0001] The present invention relates to an air conditioner.

[0002] As a background art in this technical field, there is Japanese Patent No. 6121075 (Patent Document 1). This publication describes, "A load-side heat exchanger constituting a refrigeration cycle in which a refrigerant circulates, refrigerant detection means for detecting the refrigerant, a blower fan, an indoor unit installed indoors, a control unit for controlling the indoor unit, notification means for notifying information regarding the refrigerant, and a timer for measuring time, and when the refrigerant is detected by the refrigerant detection means, the control unit causes the notification means to notify the elapsed time measured by the timer as countermeasure information for determining countermeasure procedures for refrigerant leakage." (See claims).

[0003] Japanese Patent No. 6121075

[0004] However, the technology of Patent Document 1 had room for improvement in terms of measures against the possibility of ignition of flammable refrigerant leaking from the air conditioner. Therefore, an object of the present invention is to provide an air conditioner capable of reducing the possibility of ignition even if flammable refrigerant leaks.

[0005] In order to solve the above problems, the present invention is an air conditioner using a flammable refrigerant, comprising: a calculation unit for calculating the volume of an air-conditioned space which is a space to be air-conditioned; a comparison unit for comparing the calculated volume in the air-conditioned space, which is the volume calculated by the calculation unit, with a set volume which is a preset volume for the air-conditioned space; and a countermeasure processing unit for performing a predetermined countermeasure process when the calculated volume is smaller than the set volume as a result of the comparison by the comparison unit.

[0006] According to the present invention, it is possible to provide an air conditioner capable of reducing the possibility of ignition even if flammable refrigerant leaks. Problems, configurations, and effects other than those described above will be clarified by the description of the following embodiments.

[0007] This is a schematic diagram of the air conditioner of this embodiment. This is a conceptual diagram of the control system of the air conditioner. This is a block diagram of the computer that constitutes the control system of Figure 2A. This is a perspective view of the air-conditioned space, which is the space to be air-conditioned. This is a flowchart explaining the process performed by the control device. This is a flowchart explaining the process performed by the control device. This is a perspective view of the air-conditioned space, which is the space to be air-conditioned.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a schematic diagram of the air conditioner of this embodiment. The air conditioner 100 of this embodiment comprises an outdoor unit 1 and an indoor unit 2. The outdoor unit 1 comprises a compressor 3 for compressing the refrigerant, a four-way valve 4 for switching the direction of the refrigerant flow, an outdoor heat exchanger 5 for exchanging heat between the outdoor air and the refrigerant, a propeller fan 6 for taking in outdoor air into the outdoor unit 1, and an expansion valve 7 for expanding the refrigerant.

[0009] The indoor unit 2 is equipped with an indoor heat exchanger 8 that exchanges heat between indoor air and refrigerant, and a once-through fan 9 that acts as a blower fan to draw indoor air into the indoor unit 2. In the outdoor unit 1, the compressor 3, four-way valve 4, outdoor heat exchanger 5, expansion valve 7, and indoor heat exchanger 8 are connected by piping 10, allowing the refrigerant to circulate through each component via piping 10. The refrigerant used is a flammable refrigerant (such as the A3 refrigerants described later, propane (R290), isobutane (R-600a), propylene (R-1270), or the A2L refrigerants R1234yf, R3). During cooling operation of the air conditioner 100, the four-way valve 4 is connected as shown by the solid line in Figure 1. In this case, the refrigerant discharged from the compressor 3 flows in the order of outdoor heat exchanger 5, expansion valve 7, and indoor heat exchanger 8, and then circulates back to the compressor 3 (see the solid arrow in Figure 1). On the other hand, during heating operation of the air conditioner 100, the four-way valve 4 is connected as shown by the dashed line in Figure 1. In this case, the refrigerant discharged from the compressor 3 flows in the order of indoor heat exchanger 8, expansion valve 7, and outdoor heat exchanger 5, and then circulates back to the compressor 3 (see the dashed arrow in Figure 1).

[0010] Inside the outdoor unit 1, outdoor air is drawn in by the propeller fan 6 and passes through the outdoor heat exchanger 5, where heat exchange takes place between the outdoor air and the refrigerant. Inside the indoor unit 2, indoor air is drawn in by the through-flow fan 9 and passes through the indoor heat exchanger 8, where heat exchange takes place between the indoor air and the refrigerant. The air conditioner 100 then blows out conditioned air, which is indoor air that has been heated or cooled by heat exchange with the refrigerant, to provide air conditioning for the room.

[0011] Incidentally, in recent years, the complete elimination of CFCs has been called for in order to realize a decarbonized society, and there is a need to develop air conditioners that use refrigerants with significantly lower GWP (Global Warming Potential) than before. Among the candidates for alternative refrigerants, R290 is a natural refrigerant with a very low GWP of 3, making it one of the most promising candidates. However, R290 is a highly flammable refrigerant, and in order to use it in air conditioners, measures must be taken to prevent it from igniting in the event of a leak.

[0012] As a countermeasure, an international standard (IEC 60335-2-40) has been established. This standard specifies that the amount of refrigerant to be sealed should be limited according to the installation location, and that a sensor should be installed to detect leaked refrigerant. After detecting a refrigerant leak, a blower should be operated to agitate the leaked refrigerant and prevent the formation of a flammable area of ​​the refrigerant. In contrast, Patent Document 1 discloses that in a refrigeration cycle device, when refrigerant is detected by a refrigerant detection means, a notification means is used to notify the user of the occurrence of a refrigerant leak, and the user is also notified of countermeasures to help them determine the procedure for dealing with a refrigerant leak.

[0013] However, while the technology described in Patent Document 1 allows the user to know the amount of refrigerant leaking and the rate of leakage, this information is based on the assumption that the refrigerant has already leaked. In other words, even if the conditioned space is sufficiently safe from the complete leakage of refrigerant and the subsequent agitation of the air after the air conditioner has been installed in the building, if the volume of the conditioned space changes due to changes in room partitions or redecorating by the user after installation, the possibility of unexpected ignition of the refrigerant may increase. The technology described in Patent Document 1 does not envision any countermeasures to address the increased possibility of unexpected ignition of the refrigerant when the volume of the conditioned space changes due to changes in room partitions or redecorating by the user after the air conditioner has been installed.

[0014] Therefore, the following will describe the means for dealing with the aforementioned malfunctions of the air conditioner 100. Figure 2A is a conceptual diagram of the control system of the air conditioner. This air conditioner 100 is equipped with a control device 11 which is composed of a microcomputer or the like. A detection unit 12 is connected to this control device 11 to detect the air-conditioned space S, which is the space to be air-conditioned. Various types of sensors can be used as the detection unit 12, such as a camera such as a CMOS image sensor (detection by image), an ultrasonic sensor (detection by ultrasound), or a LiDAR (detection by laser light).

[0015] The control device 11 executes the functions of the calculation unit 14, comparison unit 15, countermeasure processing unit 16, and determination unit 17 through processing based on a predetermined program. Details of the functions of each of these units will be explained below, but the control system (control device 11) is composed of a computer, for example, as shown in the block diagram of Figure 2B.

[0016] In the block diagram of Figure 2B, the computer 980 comprises a CPU 981, a storage unit 982, a communication port 983, an input / output port 984, and a media port 985. Here, the storage unit 982 comprises a RAM 982a, a ROM 982b, and an SSD (Solid State Drive) 982c.

[0017] The communication port 983 is connected to the communication circuit 986. The input / output port 984 is connected to the input / output device 987. The media port 985 reads and writes data to the recording medium 988. The ROM 982b stores the IPL (Initial Program Loader) and other programs executed by the CPU. The SSD 982c stores application programs and various data. The CPU 981 executes application programs and other data read from the SSD 982c into the RAM 982a, thereby realizing various functions as shown in Figure 2A.

[0018] Figure 3 is a perspective view of the conditioned space, which is the space to be air-conditioned. In this example, the conditioned space S is a roughly rectangular space (room). An indoor unit 2 is installed on one wall 21 of the conditioned space S. In this example, the detection unit 12 may be located on the indoor unit 2 or elsewhere within the conditioned space S. When viewed from the indoor unit 2 side, the conditioned space S has a depth of I, a width of W, and a height of h. ０ That is the case.

[0019] Figure 4 is a flowchart illustrating the process performed by the control device. First, the detection unit 12 determines the depth I, width W, and height h of the installation space (air-conditioned space S) of the indoor unit 2. ０ The calculation unit 14 detects this and, based on the detection result of the detection unit 12, calculates the volume within the air-conditioned space S (step S1). This is calculated as "I × W × h". ０ This can be determined by ". The detection unit 12 detects the air-conditioned space S using images, ultrasound, laser light, etc., as described above, and the depth I, left and right width W, and height h can be determined by images, ultrasound, laser light. ０ Since the methods for detecting these are publicly known, we will omit the details here. Incidentally, well-known and widely used methods include depth sensing cameras using images (cameras), ultrasonic sensors using ultrasound, and laser scanners and LiDAR (Light Detection And Ranging) using laser light.

[0020] The volume of the air-conditioned space S obtained as described above will be called the calculated volume V. The comparison unit 15 then compares the calculated volume V with the set volume VS (step S2). The set volume VS is a preset threshold applied to the volume of the air-conditioned space S. For example, the set volume VS can be determined as follows, based on the IEC-60335-2-40 (2022) standard. That is, when the amount of refrigerant sealed in the air conditioner 100 is m, and the lower flammability limit volume concentration, which is a physical property specific to the type of refrigerant, is LFL (Lower Flammability Limit), then "VS = m / ((1 / 2) × LFL)". In other words, the set volume VS is set to a value at which, if the volume of the air-conditioned space S falls below the set volume VS, there is a risk that if flammable refrigerant leaks into the air-conditioned space S, the volume of the air-conditioned space S will be too small, the concentration of refrigerant in the air will become too high, and there will be a risk of ignition.

[0021] If the comparison in step S2 shows that the calculated volume V ≥ the set volume VS, the countermeasure processing unit 16 performs normal processing (step S3). In other words, in this case, the user can operate the air conditioner 100 as usual. On the other hand, if the comparison in step S2 shows that the calculated volume V < the set volume VS, the countermeasure processing unit 16 displays an error (step S4). In other words, if refrigerant leaks, a warning message indicating the possibility of ignition of the refrigerant is displayed on the remote controller (not shown) of the air conditioner 100 or on the user's smartphone or other device. In addition, the processing in step S4 can be carried out by various means as long as it is a means of notifying the user of the abnormality.

[0022] In this case, the countermeasure processing unit 16 also performs abnormality processing (step S5). In other words, in this case, since there is a possibility that the refrigerant may leak, the unit takes measures such as stopping the operation of the air conditioner 100. This is because stopping the operation of the air conditioner 100 is expected to reduce the amount of refrigerant leakage even if a refrigerant leak occurs. In addition, in step S5, the air conditioner 100 can perform various other processes that can reduce the possibility of refrigerant ignition even if a refrigerant leak occurs.

[0023] The process shown in Figure 4 may be performed periodically or irregularly. For example, it is desirable to perform it at the time of the first start of operation of the air conditioner 100 for the day, prior to the start of said operation. Figure 5 is a flowchart illustrating the process performed by the control device. The process in Figure 5 can be performed at the same timing as when the process in Figure 4 is performed. First, the detection unit 12 detects the state directly below the indoor unit 2 (step S11). Then, the determination unit 17 determines whether what is detected directly below the indoor unit 2 is the floor surface of the air-conditioned space S (step S12). Specifically, if what is detected is a uniformly flat horizontal surface, it is usually the floor surface. On the other hand, if what is detected is an uneven or inclined surface, it is usually an object other than the floor surface. Since such determination methods are well known regardless of whether the detection unit 12 is a camera, ultrasonic sensor, or LiDAR, a detailed explanation is omitted. This determination indicates that if an obstacle other than the floor surface is detected directly below the indoor unit 2 (No. in step S12), there is a possibility that an ignition source is placed there. In that case, there is a risk of refrigerant leakage causing the refrigerant to ignite, so an error display (step S13) and abnormality processing (step S14) are executed. The processing in steps S13 and S14 is the same as the processing in steps S4 and S5.

[0024] If the floor surface is detected directly below the indoor unit 2 (Yes in step S12), the calculation unit 14 determines the distance between the detection unit 12 and the floor surface (step S15) and calculates the installation height of the indoor unit 2 (step S16). This installation height will be called the calculated height H (see Figure 6). The method for calculating this calculated height H is well known regardless of whether the detection unit 12 is a camera, ultrasonic sensor, or LiDAR, so a detailed explanation will be omitted. Next, the comparison unit 15 compares the calculated height H with the set height hs, which is a preset height of the indoor unit 2 (step S17). For example, if the indoor unit 2 is a wall-mounted type as in this embodiment, the set height hs is specified as 1.8m. The set height hs is set to a height that makes it easier for the refrigerant to ignite (a height at which ignition is possible) in the event of a refrigerant leak if the indoor unit 2 is installed at a height lower than that height.

[0025] If the result of this comparison is that "calculated height H ≥ set height hs", the countermeasure processing unit 16 performs normal processing (step S18). This processing is the same as in step S3. On the other hand, if "calculated height H < set height hs", the countermeasure processing unit 16 performs the processing in steps S13 and S14 described above.

[0026] The air conditioner 100 described above has the following advantageous effects. The effects of the process shown in Figure 4 will now be explained. First, after the indoor unit 2 is installed, the volume of the air-conditioned space S may be reduced due to changes in room partitions or rearrangements made by the user within the air-conditioned space S. If a refrigerant leak occurs in this situation, the concentration of refrigerant in the air within the air-conditioned space S will increase, increasing the likelihood of the leaked refrigerant igniting. The air conditioner 100 can reduce the likelihood of refrigerant ignition by judging the increased likelihood of ignition (step S2) and executing the error display (step S4) and abnormal processing (step S5) described above if there is a high possibility of ignition.

[0027] The effects of the process shown in Figure 4 will now be explained. First, after the indoor unit 2 is installed, it is determined whether the object detected directly below the indoor unit 2 is the floor surface (step S12). If it is not the floor surface but some kind of obstacle (No in step S12), there is a possibility that an ignition source is placed there, so the possibility of refrigerant ignition can be reduced by executing the error display (step S13) and abnormal processing (step S14) described above. Next, it is determined whether the calculated height H from the indoor unit 2 to the floor surface is the appropriate height (step S17). Normally, the indoor unit 2 is installed at the appropriate height by the installer during the installation work of the air conditioner 100, but there is a possibility that the installer may mistakenly install the indoor unit 2 lower than specified. In that case (H < hs in step S17), the possibility of refrigerant ignition can be reduced by executing the error display (step S13) and abnormal processing (step S14) described above.

[0028] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are explained in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described.

[0029] 12 Detection unit 14 Calculation unit 15 Comparison unit 16 Countermeasure processing unit 17 Judgment unit 100 Air conditioner

Claims

1. An air conditioner using a flammable refrigerant, comprising: a calculation unit for calculating the volume of a space to be air-conditioned, which is a space to be air-conditioned; a comparison unit for comparing the calculated volume of the space to be air-conditioned, which is the volume calculated by the calculation unit, with a set volume, which is a volume set in advance for the space to be air-conditioned; and a countermeasure processing unit for performing a predetermined countermeasure when, as a result of the comparison by the comparison unit, the calculated volume is smaller than the set volume.

2. An air conditioner having an indoor unit and using a flammable refrigerant, comprising: a calculation unit that determines the height of the indoor unit in the air-conditioned space, which is the space to be air-conditioned; a comparison unit that compares the calculated height, which is the height of the indoor unit calculated by the calculation unit, with a preset height, which is the height of the indoor unit; and a countermeasure processing unit that performs a predetermined countermeasure when, as a result of the comparison by the comparison unit, the calculated height is lower than the preset height.

3. An air conditioner that uses a flammable refrigerant and has an indoor unit, comprising: a determination unit that determines whether the area directly below the indoor unit, which is installed in a space to be air-conditioned, is the floor surface of the space to be air-conditioned; and a countermeasure processing unit that performs a predetermined countermeasure when the determination unit determines that the area directly below the indoor unit is not the floor of the space to be air-conditioned.

4. The air conditioner according to any one of claims 1 to 3, wherein the countermeasure processing unit notifies the user of the occurrence of an air conditioning problem as the countermeasure processing.

5. The air conditioner according to any one of claims 1 to 3, wherein the countermeasure processing unit stops the operation of the air conditioner as the countermeasure processing.

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