JPWO2019082242A1 - Environmental monitoring device - Google Patents

Abstract

Provided is an environmental monitoring device that can determine the deterioration of the semiconductor gas sensor for detecting refrigerant leakage and can prompt measures such as replacement of the semiconductor gas sensor before the detection accuracy of refrigerant leakage is significantly reduced. To do. Therefore, in the environmental monitoring device according to the present invention, the semiconductor sensor (100) that outputs a detection signal according to the concentration of the refrigerant in the atmosphere and the first detection signal of the semiconductor sensor (100) are set in advance. A determination unit (61) for determining that the refrigerant is leaking when the value is equal to or higher than the reference value is provided. When the detection signal of the semiconductor sensor (100) is equal to or greater than the second reference value smaller than the first reference value and less than the first reference value, the determination unit (61) determines the semiconductor sensor (100). Is determined to be deteriorated.

Description

The present invention relates to an environmental monitoring device.

A casing, a heat exchanger in which flammable refrigerant flows, a detection sensor attached to the casing to detect refrigerant leakage, and an inclination of the output value output from the detection sensor over a certain period of time in advance. An indoor unit of an air conditioner including a determination unit for determining that a refrigerant leak has occurred when it is determined to be larger than a set value is known (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2015-094524

When a semiconductor gas sensor is used as a gas sensor in an apparatus as shown in Patent Document 1, it is necessary to preheat a metal oxide (gas sensitive material) in order to make the refrigerant detectable. Therefore, if the sensor continues to be able to detect the refrigerant for a long period of time, the gas-sensitive material that has been continuously heated to a high temperature is altered by oxidation or miscellaneous gas such as silicon, and the sensitivity of the semiconductor gas sensor is lowered. In a semiconductor gas sensor whose sensitivity has decreased due to deterioration, the slope of the output value in a certain period of time becomes small even if the same amount of refrigerant leaks. Since the device of Patent Document 1 cannot detect the deterioration of the semiconductor gas sensor itself, if the deterioration of the semiconductor gas sensor progresses, the accuracy of detecting the refrigerant leakage is greatly reduced.

The present invention has been made to solve such a problem. The purpose is to determine the deterioration of the semiconductor gas sensor for detecting refrigerant leakage, and to promote measures such as replacement of the semiconductor gas sensor before the accuracy of detecting refrigerant leakage is significantly reduced. To get a monitoring device.

The environmental monitoring device according to the present invention is a semiconductor sensor that outputs a detection signal according to the concentration of the refrigerant in the atmosphere, and a refrigerant when the detection signal of the semiconductor sensor is equal to or higher than a preset first reference value. The determination unit includes a determination unit for determining that the semiconductor sensor is leaking, and the determination unit has a detection signal of the semiconductor sensor equal to or greater than a second reference value smaller than the first reference value and the first reference. If it is less than the value, it is determined that the semiconductor sensor is deteriorated.

According to the environmental monitoring device according to the present invention, deterioration of the semiconductor gas sensor for detecting the refrigerant leakage can be determined, and measures such as replacement of the semiconductor gas sensor can be taken before the detection accuracy of the refrigerant leakage is significantly lowered. It has the effect of being able to encourage.

It is sectional drawing which shows typically the structure of the room to which the environmental monitoring apparatus which concerns on Embodiment 1 of this invention is applied. It is a block diagram which shows the structure of the environment monitoring apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the determination standard of the environmental monitoring apparatus which concerns on Embodiment 1 of this invention.

A mode for carrying out the present invention will be described with reference to the accompanying drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be appropriately simplified or omitted. The present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit of the present invention.

Embodiment 1.
1 to 3 relate to the first embodiment of the present invention, FIG. 1 is a cross-sectional view schematically showing the configuration of a room to which the environmental monitoring device is applied, and FIG. 2 shows the configuration of the environmental monitoring device. The block diagram and FIG. 3 are diagrams for explaining the determination criteria of the environment monitoring device.

As shown in FIG. 1, an outdoor unit 20 and an indoor unit 30 of an air conditioner are installed in a room 10 to which the environmental monitoring device according to the first embodiment of the present invention is applied. The outdoor unit 20 is installed outside the outer wall 11 of the room 10. The indoor unit 30 is fixed at a position closer to the upper side of, for example, the inner wall 12 of the room 10. In this way, the indoor unit 30 is installed inside the room 10 to be air-conditioned, and the outdoor unit 20 is installed outside the room.

The outdoor unit 20 includes an outdoor unit heat exchanger 21, an outdoor unit fan 22, and a compressor 23. The indoor unit 30 includes an indoor unit heat exchanger 31 and an indoor unit fan 32. The indoor unit 30 and the outdoor unit 20 are connected by a refrigerant pipe 40. The refrigerant pipe 40 is provided so as to circulate between the indoor unit heat exchanger 31 and the outdoor unit heat exchanger 21. Refrigerant is sealed in the refrigerant pipe 40.

From the viewpoint of protecting the global environment, it is desirable to use a refrigerant having a small global warming potential (GWP) as the refrigerant sealed in the refrigerant pipe 40. The refrigerant sealed in the refrigerant pipe 40 is a flammable gas. This refrigerant has a larger average molecular weight than air (has a specific gravity to air greater than 1), and has the property of sinking downward in the direction of gravity in air.

Specific examples of such a refrigerant include difluoromethane (CH2F2: R32), tetrafluoropropane (CF3CF = CH2: HFO-1234yf), propane (R290), propylene (R1270), ethane (R170), and butane (R600). ), Isobutane (R600a), 1.1.1.2-Tetrafluoroethane (C2H2F4: R134a), Pentafluoroethane (C2HF5: R125), 1.3.3.3-Tetrafluoro-1-propen (CF3-). A (mixed) refrigerant composed of one or more refrigerants selected from CH = CHF: HFO-1234ze) and the like can be used.

The compressor 23 is provided on one side of the refrigerant circulation path between the indoor unit heat exchanger 31 and the outdoor unit heat exchanger 21. The compressor 23 is a device that compresses the supplied refrigerant to increase the pressure and temperature of the refrigerant. Although not shown here, an expansion valve is provided on the other side of the circulation path. The expansion valve expands the inflowing refrigerant and reduces the pressure of the refrigerant. Then, the refrigerant circulation path formed by the refrigerant pipe 40 and the indoor unit heat exchanger 31, the outdoor unit heat exchanger 21, the four-way valve, the compressor 23 and the expansion connected by the refrigerant pipe 40 on the circulation path. A refrigeration cycle (refrigerant circuit) is configured by the valves.

The refrigeration cycle configured in this way is between the indoor unit 30 and the outdoor unit 20 by exchanging heat between the refrigerant and the air in each of the indoor unit heat exchanger 31 and the outdoor unit heat exchanger 21. Works as a heat pump to transfer heat. At this time, by switching the four-way valve, the circulation direction of the refrigerant in the refrigeration cycle can be reversed to switch between the cooling operation and the heating operation.

The air conditioner is provided with a remote controller 50. A display unit 51 is provided on the front surface of the remote controller 50. The display unit 51 includes, for example, a touch panel. By operating the buttons and the like displayed on the touch panel of the display unit 51 of the remote controller 50, the user can set the power ON / OFF, the wind direction, the air volume, and the like of the air conditioner. Further, various information such as the operating status of the air conditioner is displayed to the user on the display unit 51 of the remote controller 50. The display unit 51 may be a liquid crystal display instead of the touch panel. In that case, the remote controller 50 is provided with buttons and switches for setting the power ON / OFF of the air conditioner, the wind direction, the air volume, and the like.

A semiconductor sensor 100 is provided in the housing of the indoor unit 30 of the air conditioner and at least one of the remote controller 50 of the air conditioner. FIG. 1 shows an example in which the semiconductor sensor 100 is provided in the housing of the indoor unit 30. The semiconductor sensor 100 is for detecting the refrigerant. That is, the semiconductor sensor 100 outputs a detection signal according to the concentration in the atmosphere of the same type of refrigerant as that enclosed in the refrigerant pipe 40. Specifically, for example, the semiconductor sensor 100 outputs a detection signal of a voltage proportional to the concentration of the refrigerant in the atmosphere.

The semiconductor sensor 100 includes a gas-sensitive material such as tin oxide provided on an insulating substrate such as alumina. Further, the semiconductor sensor 100 further includes a heater provided on the lower surface of the insulating substrate. These gas-sensitive materials and heaters are housed in the sensor case of the semiconductor sensor 100. In order for the semiconductor sensor 100 to be able to detect the refrigerant, it is necessary to energize the heater to heat the gas-sensitive material to 300 ° C. to 450 ° C.

Next, the configuration of the environment monitoring device will be described with reference to FIG. The environment monitoring device includes a power supply unit (not shown) for supplying electric power to energize the heater of the semiconductor sensor 100. The electric power supplied from the power supply unit to the semiconductor sensor 100 is energized to the heater of the semiconductor sensor 100. When the heater is energized, the gas-sensitive material of the semiconductor sensor 100 is heated, and the semiconductor sensor 100 is in a state where it can detect the refrigerant. In this way, the power supply unit supplies the semiconductor sensor 100 with sensor drive power for making the semiconductor sensor 100 in a state in which the refrigerant can be detected.

The environment monitoring device includes a determination unit 61. The determination unit 61 determines whether or not the refrigerant is leaking based on the detection signal of the semiconductor sensor 100. More specifically, the determination unit 61 determines that the refrigerant is leaking when the detection signal of the semiconductor sensor 100 is equal to or greater than the first reference value. The first reference value is set in advance, for example, at the time of shipment of the indoor unit 30. A specific value of the first reference value set in advance is stored in the storage unit 62 in advance. The determination unit 61 determines whether or not the refrigerant is leaking by comparing the detection signal of the semiconductor sensor 100 with the first reference value stored in the storage unit 62.

Further, the determination unit 61 also determines whether or not the semiconductor sensor 100 has deteriorated based on the detection signal of the semiconductor sensor 100. In order to determine the deterioration of the sensor, the environmental monitoring device according to the first embodiment of the present invention has another reference value, that is, a second reference, in addition to the first reference value for determining the refrigerant leakage described above. Use the value. This second reference value is set to a value smaller than the above-mentioned first reference value. Then, the determination unit 61 determines that the semiconductor sensor 100 has deteriorated when the detection signal of the semiconductor sensor 100 is equal to or more than the second reference value and less than the above-mentioned first reference value. ..

The refrigerant leakage determination and the sensor deterioration determination using the first reference value and the second reference value will be described with reference to FIG. FIG. 3 shows the relationship between the actual refrigerant concentration in the atmosphere (atmosphere concentration) and the refrigerant concentration calculated from the detection signal output from the semiconductor sensor 100 (this is referred to as “output concentration”). The unit of atmospheric concentration and output concentration is ppm. As a specific numerical example, FIG. 3 shows the relationship between the atmospheric concentration and the output concentration when the exposure time of the semiconductor sensor 100 is 0 hours, 1000 hours, 2000 hours, 3000 hours, 5000 hours, and 10000 hours, respectively. Is shown.

First, as described above, the semiconductor sensor 100 needs to preheat the metal oxide (gas-sensitive material) in order to make the refrigerant detectable. Therefore, if the semiconductor sensor 100 continues to be in a state where the refrigerant can be detected, the gas-sensitive material that has been continuously heated to a high temperature is altered by oxidation or miscellaneous gas such as silicon, and the sensitivity is lowered. Therefore, the longer the exposure time, the lower the sensitivity of the semiconductor sensor 100.

As shown in the figure, at 0 hours of exposure, the atmospheric concentration and the output concentration are in agreement. However, the longer the exposure time, the higher the output concentration when the atmospheric concentration is low. Specifically, in the example of the figure, the output concentration when the atmospheric concentration is 1000 ppm is 1000 ppm at 0 hours of exposure, 1500 ppm at 1000 hours of exposure, 2000 ppm at 2000 hours of exposure, and so on. The longer the exposure time, the higher the output concentration of the semiconductor sensor 100 even if the atmospheric concentration is the same 1000 ppm.

On the other hand, the output concentration when the atmospheric concentration is high becomes lower as the exposure time becomes longer. Specifically, in the example of the figure, the output concentration when the atmospheric concentration is 10000 ppm is 10000 ppm at 0 hours of exposure, 9500 ppm at 1000 hours of exposure, 9000 ppm at 2000 hours of exposure, and so on. As the exposure time becomes longer, the output concentration of the semiconductor sensor 100 becomes lower even if the atmospheric concentration is the same 10000 ppm. Therefore, the longer the exposure time, the smaller the rate of change in the output concentration when the atmospheric concentration changes. That is, the longer the exposure time, the lower the sensitivity of the semiconductor sensor 100.

In the example of the figure, the first reference value is set to 8000 ppm, and the second reference value is set to 2500 ppm. As described above, as the exposure time becomes longer, the output concentration when the atmospheric concentration is low becomes higher, and the output concentration when the atmospheric concentration is high becomes lower. Therefore, when the exposure time becomes long, the output concentration gradually increases even if the refrigerant leakage does not occur, and exceeds the second reference value of 2500 ppm. Further, when the exposure time becomes long, even if the refrigerant leaks, the output concentration decreases to less than the first reference value of 8000 ppm.

Therefore, in the environmental monitoring device according to the first embodiment of the present invention, the determination unit 61 has the detection signal of the semiconductor sensor 100 less than the first reference value for determining the refrigerant leakage, and the determination unit 61 is the first. When it is equal to or more than the reference value of 2, it is determined that the semiconductor sensor 100 is deteriorated. By doing so, it is possible to determine the deterioration of the semiconductor gas sensor for detecting the refrigerant leakage, and it is possible to promote measures such as replacement of the semiconductor gas sensor before the detection accuracy of the refrigerant leakage is significantly reduced. Is.

Before the detection signal of the semiconductor sensor 100 becomes the first reference value, the detection signal must be in a state of being equal to or more than the second reference value and less than the first reference value. Therefore, if the detection signal exceeds the first reference value after the detection signal reaches the second reference value or more and before the preset fixed time elapses, the determination unit 61 uses the semiconductor sensor. It may be determined that the refrigerant leaks instead of the deterioration of 100. Then, when the detection signal does not exceed the first reference value even after the above-mentioned fixed time elapses after the detection signal reaches the second reference value or more, the determination unit 61 of the semiconductor sensor 100 It may be determined that the deterioration has occurred.

The second reference value is also stored in the storage unit 62 in the same manner as the first reference value. The specific value of the second reference value may be set in advance at the time of shipment of the indoor unit 30, for example, or the output signal from the semiconductor sensor 100 at the time of the first operation after the installation of the air conditioner is used. It may be set using. In the latter case, the second reference value is obtained by adding a predetermined constant value to the output concentration of the output signal from the semiconductor sensor 100 when the air conditioner is first operated after installation. At this time, when the output concentration of the semiconductor sensor 100 is the first reference value, the difference between the actual atmosphere concentration and the output concentration is within a certain range, for example, within ± 25% of the atmosphere concentration. It is desirable to set the reference value of.

It is desirable that the determination unit 61 automatically determine whether or not the semiconductor sensor 100 has deteriorated at least once a year. Further, it is desirable that the determination result is obtained within 30 seconds after the determination is started.

In addition to periodically determining whether or not the semiconductor sensor 100 has deteriorated at a frequency of once or more a year, the determination unit 61 may perform the determination in the following cases. .. That is, first, the determination unit 61 may determine whether or not the semiconductor sensor 100 has deteriorated each time the remote controller 50 is operated. By doing so, it is possible to confirm the deterioration of the semiconductor sensor 100 every time the user tries to use the air conditioner.

Further, the determination unit 61 may determine whether or not the semiconductor sensor 100 has deteriorated when the inspection button 63 is operated. The inspection button 63 is provided on at least one of the indoor unit 30, the remote controller 50, and the outdoor unit 20. By doing so, the user or the maintenance worker can confirm the deterioration of the semiconductor sensor 100 at a desired time.

When the air conditioner is connected to the Internet via HEMS (Home Energy Management System) or the like, for example, whether or not the semiconductor sensor 100 is deteriorated from a smartphone, a PC, or the like via the Internet. It may be possible to make a judgment. In this way, the convenience can be further improved by making it possible to determine whether or not the semiconductor sensor 100 has deteriorated by remote control.

The operation of the air conditioner is controlled according to the determination result of the determination unit 61. For example, if the determination result of the determination unit 61 is that the refrigerant has leaked, the operation of the air conditioner is stopped in an emergency. Further, when the determination result of the determination unit 61 is that the semiconductor sensor 100 has deteriorated, the operation of the air conditioner stops abnormally.

In the configuration example of the first embodiment, the determination result of the determination unit 61 is transmitted to the remote controller 50. The remote controller 50 that has received the determination result of the determination unit 61 displays on the display unit 51 the operating status of the air conditioner according to the determination result of the determination unit 61, for example, in character information.

Specifically, for example, when the determination result of the determination unit 61 is that the refrigerant has leaked and the operation of the air conditioner is emergency stopped, the display unit 51 displays "emergency stop". Further, the determination result of the determination unit 61 is that the semiconductor sensor 100 has deteriorated, and when the operation of the air conditioner stops abnormally, the display unit 51 displays "abnormal stop". When the operating state of the air conditioner is a normal stop, for example, "stop" is simply displayed on the display unit 51. Further, in the case of operation of the air conditioner, for example, "cooling", "heating", "dehumidification", "blower" and the like are displayed on the display unit 51 according to the operation type.

The display unit 51 of the remote controller 50 configured as described above is an example of the notification means for notifying the operating status of the air conditioner according to the determination result of the determination unit 61 in the first embodiment of the present invention. The configuration of the notification means is not limited to this example. For example, the notification means may be provided on at least one of the indoor unit 30 and the remote controller 50. Further, the notification form by the notification means is not limited to the display of character information. In addition, for example, sound may be produced by a speaker, LED may be emitted, graphic information may be displayed, or a combination thereof may be used. Further, the notification means may notify the determination result itself of the determination unit 61.

By providing such a notification means, the user can easily know the cause of the stoppage of the operation of the air conditioner. In addition, when the semiconductor sensor 100 deteriorates, it is possible to prompt the sensor to be replaced. Further, even when a refrigerant leak is detected, prompt response can be promoted.

The present invention can be used in an environmental monitoring device that detects that a refrigerant is leaking based on a detection signal of a semiconductor sensor. It can also be used for air conditioners, water heaters, showcases, refrigerators, etc. equipped with such an environmental monitoring device.

10 Room 11 Outer wall 12 Inner wall 20 Outdoor unit 21 Outdoor unit heat exchanger 22 Outdoor unit fan 23 Compressor 30 Indoor unit 31 Indoor unit heat exchanger 32 Indoor unit fan 40 Refrigerant piping 50 Remote control 51 Display unit 61 Judgment unit 62 Storage unit 63 Inspection button 100 Semiconductor type sensor

The environmental monitoring device according to the present invention is a semiconductor sensor that outputs a detection signal according to the concentration of the refrigerant in the atmosphere, and a refrigerant when the detection signal of the semiconductor sensor is equal to or higher than a preset first reference value. The determination unit is provided with a determination unit for determining that the sensor is leaking, and the determination unit is preset after the detection signal of the semiconductor sensor becomes equal to or greater than the second reference value smaller than the first reference value . If the value exceeds the first reference value before a certain period of time elapses, it is determined that the refrigerant is leaking, and after the detection signal of the semiconductor sensor reaches the second reference value or more, the above. If it is less than the first reference value even after a certain period of time has elapsed, it is determined that the semiconductor sensor has deteriorated.

Claims (6)

A semiconductor sensor that outputs a detection signal according to the concentration of refrigerant in the atmosphere,
A determination unit for determining that the refrigerant is leaking when the detection signal of the semiconductor sensor is equal to or higher than a preset first reference value is provided.
When the detection signal of the semiconductor sensor is equal to or greater than the second reference value smaller than the first reference value and less than the first reference value, the determination unit deteriorates the semiconductor sensor. Environmental monitoring device that determines that there is. The environmental monitoring device according to claim 1, wherein the semiconductor sensor is provided in at least one of the housing of the indoor unit of the air conditioner and the remote controller of the air conditioner. The environmental monitoring device according to claim 2, wherein the second reference value is set by using an output signal from the semiconductor sensor when the air conditioner is first operated after installation. The environmental monitoring device according to claim 2 or 3, wherein the determination unit determines whether or not the semiconductor sensor is deteriorated each time the remote controller is operated. Any one of claims 2 to 4, further provided with a notification means provided on at least one of the indoor unit and the remote controller to notify the operating status of the air conditioner according to the determination result of the determination unit. The environmental monitoring device described in. The determination unit determines whether or not the semiconductor sensor is deteriorated when an inspection button provided on at least one of the indoor unit, the remote controller, and the outdoor unit of the air conditioner is operated. The environmental monitoring device according to any one of claims 2 to 5.

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