JP2009030839A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner capable of detecting clogging of an use-side heat exchanger while preventing a constitution from being complicated. <P>SOLUTION: This air conditioner comprising a refrigerant circuit constituted by successively connecting a compressor 8, a heat source-side heat exchanger 10, an expansion valve 14 and the use-side heat exchanger 22, further comprises a pressure sensor 26 for detecting a pressure of a refrigerant at a suction side of the compressor 8 in a cooling operation, and a control portion 18 for detecting the clogging of the use-side heat exchanger 22 on the basis of the pressure detected by the pressure sensor 26. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air conditioner.

  Conventionally, various air conditioners that perform air conditioning of a predetermined space are known. Such an air conditioner includes a refrigerant circuit in which a compressor, a heat source side heat exchanger, an expansion mechanism, and a use side heat exchanger are connected in order, and in the use side heat exchanger, Cooling air is generated by generating cold air by heat exchange with the surrounding air and blowing the cold air into the predetermined space.

Patent Literature 1 below shows an example of such an air conditioner. The air conditioner of Patent Document 1 is configured to detect clogging and display a clogging display on a display unit when a filter of an indoor unit including a use side heat exchanger is clogged. Specifically, the odor sensor detects the difference in the odor of the air before and after the filter of the indoor unit, and if the odor difference exceeds a predetermined value, it is determined that the blockage is clogged, and the fluctuation rate of the operating current of the compressor is Japanese Patent Application Laid-Open No. 2004-151561 discloses a configuration for determining clogging when the value exceeds a predetermined value, a configuration for determining clogging when the vibration state of the fan motor of the indoor unit or the load state of the fan motor exceeds a specified value, and the like.
Japanese Patent Application Laid-Open No. 5-223212

  However, in the configuration disclosed in Patent Document 1, it is necessary to provide various detection means for detecting clogging, a control means for detecting clogging, and the like, and there is a problem that the configuration of the air conditioner is complicated. .

  The present invention has been made to solve the above-described problems, and the object thereof is to detect clogging of the use-side heat exchanger while suppressing the configuration from becoming complicated. It is to provide an air conditioner.

  In order to achieve the above object, an air conditioner according to the present invention includes an air conditioner including a refrigerant circuit in which a compressor, a heat source side heat exchanger, an expansion mechanism, and a use side heat exchanger are sequentially connected. A pressure sensor for detecting the refrigerant pressure on the suction side of the compressor during cooling operation, and detecting clogging of the use side heat exchanger during cooling operation based on the detected pressure of the pressure sensor And a control unit.

  In this air conditioner, when the use-side heat exchanger is clogged, the detected pressure of the pressure sensor changes. That is, when the use side heat exchanger is clogged, heat exchange in the use side heat exchanger is not sufficiently performed, and the evaporation rate of the refrigerant in the use side heat exchanger during cooling operation is reduced. The pressure of the refrigerant gas on the suction side of the compressor at the time decreases. Thereby, the detection pressure of the said pressure sensor falls and it can detect clogging of the utilization side heat exchanger based on it.

  And the structure which monitors the pressure of the refrigerant | coolant in the suction side of the compressor at the time of such cooling operation using a pressure sensor is generally provided in the air conditioner in order to ensure the safe driving | operation of a compressor. . That is, the compressor compresses the refrigerant gas, and may become inoperable when a large amount of liquid refrigerant enters. For this reason, always monitor whether the pressure of the refrigerant on the suction side of the compressor during cooling operation has decreased, and monitor whether refrigerant containing a predetermined percentage or more of the liquid is sucked into the compressor. Is usually done. In the air conditioner according to the present invention, it is possible to detect the clogging of the use side heat exchanger by utilizing the pressure detection of the refrigerant by the pressure sensor normally provided as described above. The clogging of the use side heat exchanger can be detected without particularly increasing the number of control means. Therefore, in this air conditioner, it is possible to detect clogging of the use side heat exchanger while suppressing the complication of the configuration. The “clogging of the use side heat exchanger” in the present invention is a concept including clogging of heat exchange fins of the use side heat exchanger and clogging of an air filter attached to the use side heat exchanger. is there.

  In the air conditioner, it is preferable that the control unit detects clogging of the use side heat exchanger based on a decrease in pressure detected by the pressure sensor below a predetermined threshold value. With this configuration, it is possible to determine clogging of the use side heat exchanger based on the determination criteria that the pressure detected by the pressure sensor has fallen below a predetermined threshold value, and thus more accurately use side heat exchange. Clogging of the vessel can be detected.

  An air conditioner according to the present invention is an air conditioner provided with a refrigerant circuit in which a compressor, a heat source side heat exchanger, an expansion mechanism, and a use side heat exchanger are connected in order. A first refrigerant temperature sensor that detects the temperature of the refrigerant before being introduced into the use-side heat exchanger during operation, and a second refrigerant that detects the temperature of the refrigerant after being discharged from the use-side heat exchanger during cooling operation The difference between the temperature sensor and the detected temperature of the first refrigerant temperature sensor with respect to the temperature detected by the second refrigerant temperature sensor is calculated, and the use-side heat exchanger is clogged based on the calculated detected temperature difference. And a control unit for detection.

  In this air conditioner, when the use-side heat exchanger is clogged, a change occurs in the difference in the detected temperature of the first refrigerant temperature sensor with respect to the detected temperature of the second refrigerant temperature sensor. Specifically, when the use side heat exchanger is clogged, the heat exchange in the use side heat exchanger is not sufficiently performed, and the temperature of the refrigerant after coming out of the use side heat exchanger during cooling operation is too low. It will not rise. For this reason, the difference in the temperature of the refrigerant before being introduced into the use side heat exchanger during the cooling operation with respect to the temperature of the refrigerant after leaving the use side heat exchanger during the cooling operation, that is, before and after the use side heat exchanger. The temperature difference of the refrigerant is reduced. Thereby, the difference of the detected temperature of the 1st refrigerant | coolant temperature sensor with respect to the detected temperature of a 2nd refrigerant | coolant temperature sensor becomes small, and the clogging of the utilization side heat exchanger can be detected based on it.

  And the structure which monitors the temperature difference of the refrigerant | coolant before and behind a utilization side heat exchanger using such a 1st refrigerant | coolant temperature sensor and a 2nd refrigerant | coolant temperature sensor is the refrigerant | coolant of a utilization side heat exchanger at the time of air_conditionaing | cooling operation. It is generally provided in an air conditioner in order to monitor whether evaporation is normally performed. In the air conditioner of the present invention, the use side heat exchange is diverted using the detection of the refrigerant temperature difference before and after the use side heat exchanger using the first refrigerant temperature sensor and the second refrigerant temperature sensor normally provided as described above. The clogging of the use-side heat exchanger can be detected without particularly increasing the number of detection means and control means for clogging detection. Therefore, in this air conditioner, it is possible to detect clogging of the use side heat exchanger while suppressing the complication of the configuration.

  In the above air conditioner, it is preferable that the control unit detects clogging of the use side heat exchanger based on the difference between the calculated detected temperatures being smaller than a predetermined threshold value. According to this configuration, the use-side heat exchanger is clogged based on the determination that the difference between the detected temperature of the first refrigerant temperature sensor and the detected temperature of the second refrigerant temperature sensor is smaller than a predetermined threshold value. Therefore, the clogging of the use side heat exchanger can be detected more accurately.

  The air conditioner includes a use side heat exchanger temperature sensor that detects a use side heat exchanger temperature, the use side heat exchanger includes a plurality of heat exchange fins, and the control unit includes the use side heat exchanger. After detecting the clogging of the heat exchanger, when the temperature detected by the use side heat exchanger temperature sensor is equal to or higher than a predetermined determination temperature, it is determined that the clogging of the use side heat exchanger is due to dust, When the temperature detected by the use side heat exchanger temperature sensor is lower than the predetermined discrimination temperature, it is preferable to determine that the clogging of the use side heat exchanger is due to frost formation of the plurality of heat exchange fins. . If comprised in this way, it can be judged reliably whether the cause of the detected clogging of the use side heat exchanger is due to dust or frost formation on the heat exchange fins.

  In this case, when the control unit determines that the clogging of the use side heat exchanger is caused by dust, the display unit includes a display device capable of displaying the clogging of the use side heat exchanger. Is preferred. If comprised in this way, when clogging with dust arises in the utilization side heat exchanger, a user can be made to recognize clogging of the utilization side heat exchanger by the clogging display of a display apparatus.

  In the configuration including the use side heat exchanger temperature sensor, when the control unit determines that the clogging of the use side heat exchanger is caused by frost formation of the plurality of heat exchange fins, the defrost operation is performed. Is preferably performed. If comprised in this way, even when the clogging of the heat exchange fin by frost formation is detected, the defrosting of the heat exchange fin can be performed by the defrost operation, and the clogging of the heat exchange fin can be eliminated.

  As described above, according to the present invention, it is possible to detect clogging of the use side heat exchanger while suppressing the configuration from becoming complicated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a refrigerant system diagram showing a state during cooling operation of an air conditioner according to an embodiment of the present invention, and FIG. 2 schematically shows a structure of a use side heat exchanger 22 in FIG. It is a figure. FIG. 3 is a refrigerant system diagram illustrating a state during heating operation and defrost operation of the air conditioner illustrated in FIG. 1. First, with reference to FIGS. 1-3, the structure of the air conditioner by one Embodiment of this invention is demonstrated.

  The air conditioner by this embodiment is provided with the outdoor unit 2, the indoor unit 4, and the remote controller 6, as shown in FIG.

  The indoor unit 4 is installed in a predetermined indoor space, and the outdoor unit 2 is installed outside the space.

  In the air conditioner, the indoor unit 4 generates cool air using the refrigerant cooled by the outdoor unit 2, and cools the indoor space by supplying the cool air to the indoor space. The indoor unit 4 generates warm air using the refrigerant heated by the outdoor unit 2 and supplies the warm air to the indoor space to heat the indoor space.

  The outdoor unit 2 includes a compressor 8, a heat source side heat exchanger 10 (outdoor heat exchange), an intake fan 12, an expansion valve 14, a four-way switching valve 16, and a control unit 18. The indoor unit 4 includes a use side heat exchanger 22 (indoor heat exchange) and a blower fan 24. And the refrigerant circuit is comprised by connecting the said compressor 8, the said heat source side heat exchanger 10, the expansion valve 14, and the utilization side heat exchanger 22 in order with piping.

  The compressor 8 sucks the low-pressure refrigerant gas coming out through the use-side heat exchanger 22 during the cooling operation, and discharges the refrigerant gas at a high pressure. On the other hand, the compressor 8 heats the heat source-side heat exchanger 10 during the heating operation. The low-pressure refrigerant gas coming out through the refrigerant is sucked, and the refrigerant gas is discharged at a high pressure.

  The heat source side heat exchanger 10 cools and condenses the high-temperature and high-pressure refrigerant gas discharged from the compressor 8 during the cooling operation, while the low-temperature and low-pressure liquid flowing through the expansion valve 14 during the heating operation. The refrigerant is heated to evaporate. The intake fan 12 is provided adjacent to the heat source side heat exchanger 10. During the cooling operation, the intake fan 12 is driven to take in air from the outside of the outdoor unit 2, and the heat source side heat exchanger 10 performs heat exchange between the refrigerant gas and the taken-in air, thereby causing the high temperature and high pressure. The refrigerant gas condenses. On the other hand, during the heating operation, air is taken in from the outside of the outdoor unit 2 by driving the intake fan 12, and the heat source side heat exchanger 10 performs heat exchange between the liquid refrigerant and the taken-in air, thereby reducing the low temperature. The low-pressure liquid refrigerant evaporates.

  While the expansion valve 14 is in a state in which the high-temperature and high-pressure liquid refrigerant formed by condensing the refrigerant gas in the heat source side heat exchanger 10 during the cooling operation can be easily evaporated at a low temperature and low pressure, The high-temperature and high-pressure liquid refrigerant produced by condensing the refrigerant gas in the use-side heat exchanger 22 is set to a low temperature and low pressure so that it can be easily evaporated. The expansion valve 14 is included in the concept of the expansion mechanism in the present invention.

  The use-side heat exchanger 22 generates cold air by heat exchange between the liquid refrigerant that has become low-temperature and low-pressure by the expansion valve 14 and air around the use-side heat exchanger 22 during the cooling operation, and the low-temperature and low-pressure. While the liquid refrigerant is evaporated, warm air is generated by heat exchange between the high-temperature and high-pressure refrigerant gas discharged from the compressor 8 and the air around the use-side heat exchanger 22 during the heating operation, and the high-temperature and high-pressure refrigerant is used. Condenses the gas. The blower fan 24 is provided adjacent to the use side heat exchanger 22. During the cooling operation, the blower fan 24 is driven to blow the cool air generated by the use side heat exchanger 22 into the indoor space, while during the heating operation, the blower fan 24 is driven to drive the use side heat exchanger 22. The warm air generated in is blown into the indoor space. And the use side heat exchanger 22 has the heat exchanger tube 22a and the several heat exchange fin 22b, as shown in FIG.

  The heat transfer tube 22a is composed of a metal tube bent a plurality of times, and the low-temperature and low-pressure liquid refrigerant flowing from the expansion valve 14 circulates inside during the cooling operation, and is discharged from the compressor 8 during the heating operation. High-temperature and high-pressure refrigerant gas circulates inside. A pipe connected to the expansion valve 14 is connected to one end 22c of the heat transfer tube 22a, while a pipe connected to the compressor 8 is connected to the other end 22d. And the heat exchanger tube 22a has the some linear part 22e extended linearly, and the some bending part 22f.

  The straight portions 22e are substantially parallel to each other and arranged at a predetermined interval. And each bending part 22f has connected the edge parts of adjacent linear part 22e and 22e. That is, the heat transfer tube 22a bent a plurality of times is configured by alternately arranging the straight portions 22e and the bent portions 22f.

  The plurality of heat exchange fins 22b are made of a flat metal plate and increase the heat transfer area. The plurality of heat exchange fins 22b are attached to the plurality of straight portions 22e of the heat transfer tube 22a. The heat exchange fins 22b are disposed so as to be orthogonal to the linear portion 22e, and are disposed at substantially equal intervals in the longitudinal direction of the linear portion 22e. The heat exchange fins 22b have through holes corresponding to the respective straight portions 22e, and the heat exchange fins 22b and the heat transfer tubes 22a are integrally formed with the respective straight portions 22e being inserted into the respective through holes. It has become.

  In the use-side heat exchanger 22, a low-temperature liquid refrigerant flowing in the heat transfer tube 22a through the heat transfer tubes 22a and the heat exchange fins 22b and air around the heat transfer tubes 22a and the heat exchange fins 22b during the cooling operation The heat exchange is performed. As a result, during the cooling operation, the surrounding air is cooled to generate cool air, the temperature of the liquid refrigerant in the heat transfer tube 22a rises, and the liquid refrigerant evaporates. On the other hand, during the heating operation, heat exchange is performed between the high-temperature refrigerant gas flowing through the heat transfer tubes 22a and the air around the heat transfer tubes 22a and the heat exchange fins 22b via the heat transfer tubes 22a and the heat exchange fins 22b. As a result, during the heating operation, the surrounding air is cooled to generate cold air, and the temperature of the refrigerant gas in the heat transfer tube 22a is reduced, and the refrigerant gas is condensed.

  Although not shown, an air filter may be attached to the use-side heat exchanger 22 in the indoor unit 4 so that air that has passed through the air filter flows between the heat exchange fins 22b. In this case, it is possible to prevent dust from adhering to the heat transfer tubes 22a and the heat exchange fins 22b.

  The four-way switching valve 16 is for switching the refrigerant circulation direction in the refrigerant circuit. With this four-way switching valve 16, a cooling operation is performed in which refrigerant is circulated from the compressor 8 through the heat source side heat exchanger 10, the expansion valve 14, and the use side heat exchanger 22 in this order to return to the compressor 8. (State of FIG. 1), heating operation and defrost for circulating refrigerant from the compressor 8 through the use side heat exchanger 22, the expansion valve 14, and the heat source side heat exchanger 10 in this order to return to the compressor 8 The operation (state shown in FIG. 3) can be switched.

  Specifically, the four-way switching valve 16 is connected to the discharge part 8 a of the compressor 8, the suction part 8 b of the compressor 8, the heat source side heat exchanger 10, and the use side heat exchanger 22. The four-way switching valve 16 allows the refrigerant discharged from the discharge portion 8a of the compressor 8 to flow to the heat source side heat exchanger 10 and the refrigerant from the use side heat exchanger 22 during the cooling operation of the air conditioner. While flowing into the suction portion 8b of the compressor 8, during the heating operation and defrost operation of the air conditioner, the refrigerant discharged from the discharge portion 8a of the compressor 8 flows to the use side heat exchanger 22 and the heat source side heat. The refrigerant flow path is switched so that the refrigerant from the exchanger 10 flows into the suction portion 8b of the compressor 8.

  A pressure sensor 26 is provided in a pipe connecting the use side heat exchanger 22 and the compressor 8. The pressure sensor 26 detects the refrigerant pressure Lp on the suction side of the compressor 8 during the cooling operation, and outputs an electric signal corresponding to the detected pressure to the control unit 18.

  In addition, a first refrigerant temperature sensor 28 is provided in a pipe connecting the expansion valve 14 and the use side heat exchanger 22. The first refrigerant temperature sensor 28 detects the temperature of the refrigerant before being introduced into the heat transfer tube 22a of the use side heat exchanger 22 during the cooling operation, and outputs an electric signal corresponding to the detected temperature to the control unit 18. Output to.

  A second refrigerant temperature sensor 30 is provided in a pipe connecting the use side heat exchanger 22 and the compressor 8. The second refrigerant temperature sensor 30 detects the temperature of the refrigerant after exiting the use side heat exchanger 22 during the cooling operation, and outputs an electric signal corresponding to the detected temperature to the control unit 18.

  The use side heat exchanger 22 is provided with a use side heat exchanger temperature sensor 32. The use side heat exchanger temperature sensor 32 detects the temperature of the heat transfer tube 22 a of the use side heat exchanger 22 and outputs an electric signal corresponding to the detected temperature to the control unit 18.

  The controller 18 controls each part of the outdoor unit 2 and the indoor unit 4 and has a function of detecting clogging of the use side heat exchanger 22.

  Specifically, the control unit 18 performs drive control of the compressor 8, drive control of the intake fan 12, opening / closing control of the expansion valve 14, drive control of the blower fan 24, switch control of the four-way switching valve 16, and the like. Further, the control unit 18 monitors the refrigerant pressure Lp on the suction side of the compressor 8 during the cooling operation in order to ensure the safe operation of the compressor 8. That is, the compressor 8 compresses the refrigerant gas, and may become inoperable when a large amount of liquid refrigerant enters. For this reason, the control unit 18 always monitors whether the refrigerant pressure Lp on the suction side of the compressor 8 during the cooling operation is decreasing or not by the detected pressure of the pressure sensor 26, and includes the refrigerant containing a predetermined ratio or more of the liquid droplets. Is monitored by the compressor 8.

  In addition, the control unit 18 confirms whether the refrigerant is normally evaporated in the use-side heat exchanger 22 during the cooling operation, and the first refrigerant temperature sensor 28 with respect to the temperature detected by the second refrigerant temperature sensor 30. The temperature difference SH of the refrigerant before and after the use-side heat exchanger 22 during the cooling operation is calculated, and the temperature difference SH of the refrigerant is constantly monitored. That is, when the temperature difference SH of the refrigerant before and after the use side heat exchanger 22 becomes small during the cooling operation, the heat exchange in the use side heat exchanger 22 is not sufficiently performed, and the refrigerant evaporates. May not be done properly. Therefore, the control unit 18 calculates the refrigerant temperature difference SH before and after the use side heat exchanger 22 based on the detected temperature of the first refrigerant temperature sensor 28 and the detected temperature of the second refrigerant temperature sensor 30. By monitoring the temperature difference SH, it is confirmed whether the refrigerant is normally evaporated in the use side heat exchanger 22 during the cooling operation.

  If clogging occurs in the use-side heat exchanger 22, the heat exchange efficiency decreases, or if the clogging is caused by dust adhering to the heat exchange fins 22b and the heat transfer tubes 22a, it is included in the dust. The heat exchange fins 22b and the heat transfer tubes 22a may be corroded by acid and moisture. For this reason, the control part 18 detects clogging of the use side heat exchanger 22, displays it on the display part 6a of the remote controller 6 mentioned later, and eliminates clogging of the use side heat exchanger 22 to a user. Prompt.

  Specifically, the detection of the clogging of the use side heat exchanger 22 by the control unit 18 is performed by detecting the pressure detected by the pressure sensor 26, that is, the refrigerant pressure Lp on the suction side of the compressor 8 during the cooling operation, This is performed based on the difference between the detected temperature of the first refrigerant temperature sensor 28 and the detected temperature of the refrigerant temperature sensor 30, that is, the refrigerant temperature difference SH before and after the use side heat exchanger 22 during the cooling operation.

  That is, when the use side heat exchanger 22 is clogged, heat exchange in the use side heat exchanger 22 is not sufficiently performed, and the evaporation rate of the liquid refrigerant in the use side heat exchanger 22 is lowered during the cooling operation. Therefore, the refrigerant gas pressure Lp on the suction side of the compressor 8 during the cooling operation decreases. Further, when the use side heat exchanger 22 is clogged, the heat exchange in the use side heat exchanger 22 is not sufficiently performed, and the temperature of the refrigerant after leaving the use side heat exchanger 22 during the cooling operation is too low. It will not rise. For this reason, the temperature difference SH of the refrigerant before and after the use side heat exchanger 22 is reduced. Therefore, the control unit 18 is used based on the fact that the pressure Lp has dropped below a preset threshold value or the refrigerant temperature difference SH has become smaller than a preset threshold value. The side heat exchanger 22 is configured to detect clogging.

  The clogging of the use side heat exchanger 22 includes clogging due to dust and clogging due to frost formation on the heat exchange fins 22b. Therefore, based on the temperature detected by the use side heat exchanger temperature sensor 32, the control unit 18 determines whether the detected cause of the clogging of the use side heat exchanger 22 is due to dust or frost formation on the heat exchange fins 22b. Judge whether or not. That is, the control unit 18 indicates that the clogging is due to frost formation on the heat exchange fins 22b when the temperature detected by the use side heat exchanger temperature sensor 32 is lower than a predetermined determination temperature. On the other hand, if the detected temperature of the use side heat exchanger temperature sensor 32 is equal to or higher than the determination temperature, it is determined that the clogging is caused by dust.

  When the control unit 18 determines that the clogging is caused by dust, the control unit 18 displays the occurrence of clogging of the use side heat exchanger 22 on the display unit 6a of the remote controller 6 described later, while the clogging is a heat exchange fin. When it is determined that the frost formation is caused by 22b, the four-way switching valve 16 is controlled to perform the defrost operation.

  The remote controller 6 performs various settings and operations of the air conditioner, and includes a display unit 6a for displaying various states of the air conditioner. The remote controller 6 is configured to receive a signal from the control unit 18 and display a display indicating clogging of the use side heat exchanger 22 on the display unit 6a. The remote controller 6 is included in the concept of the display device in the present invention.

  FIG. 4 is a flowchart for explaining an operation when detecting clogging of the use side heat exchanger 22 in the air conditioner according to the present embodiment. Next, with reference to FIGS. 1-4, the operation | movement at the time of detecting clogging of the utilization side heat exchanger 22 in this embodiment is demonstrated.

  First, the air conditioner is in a cooling operation, and the refrigerant discharged from the compressor 8 passes through the heat source side heat exchanger 10, the expansion valve 14, and the use side heat exchanger 22 in order as shown in FIG. Circulating to return to 8. At this time, the detected pressure of the pressure sensor 26, that is, the refrigerant pressure Lp on the suction side of the compressor 8 is constantly input to the control unit 18. In parallel, the controller 18 detects the temperature detected by the first refrigerant temperature sensor 28, that is, the temperature of the refrigerant before being introduced into the use-side heat exchanger 22, and the temperature detected by the second refrigerant temperature sensor 30; That is, the temperature of the refrigerant after leaving the use side heat exchanger 22 is constantly input. Further, the temperature detected by the use side heat exchanger temperature sensor 32, that is, the temperature of the use side heat exchanger 22 is constantly input to the control unit 18.

  The control unit 18 constantly monitors the refrigerant pressure Lp on the suction side of the compressor 8 during the cooling operation in order to ensure the safe operation of the compressor 8 and uses the heat exchanger 22 on the use side during the cooling operation. In order to confirm whether or not the refrigerant evaporates normally, the refrigerant temperature difference SH before and after the use side heat exchanger 22 is calculated, and the refrigerant temperature difference SH is constantly monitored.

  In such a state, the control unit 18 diverts the detection of the refrigerant pressure Lp on the suction side of the compressor 8 and the detection of the refrigerant temperature difference SH before and after the use side heat exchanger 22. Clogging of the heat exchanger 22 is detected. Specifically, the control unit 18 determines that the pressure Lp is lower than a predetermined threshold value, or the refrigerant temperature difference SH is lower than a predetermined threshold value. It is determined whether it is smaller (step S1).

  When the control unit 18 determines that the pressure Lp is lower than the threshold value or the temperature difference SH of the refrigerant is smaller than the threshold value, the use side heat exchange is next performed. It is determined whether or not the temperature of the vessel 22 is equal to or higher than a predetermined determination temperature set in advance (step S2). On the other hand, when the control unit 18 determines that the pressure Lp is equal to or greater than a threshold value and the refrigerant temperature difference SH is equal to or greater than the threshold value, the control unit 18 determines the pressure difference Lp and the refrigerant temperature difference. The judgment regarding SH is repeatedly performed.

  When the control unit 18 determines that the temperature of the use side heat exchanger 22 is equal to or higher than the determination temperature, the control unit 18 determines that clogging due to dust has occurred in the use side heat exchanger 22, and the remote controller 6. A predetermined signal is transmitted to display on the display unit 6a of the remote controller 6 a display indicating clogging of the use side heat exchanger 22 (step S3). As a result, the user can recognize the clogging of the use side heat exchanger 22 and prompt the user to clean the heat transfer tubes 22a and the heat exchange fins 22b of the use side heat exchanger 22 and the air filter.

  On the other hand, when the control unit 18 determines that the temperature of the use side heat exchanger 22 is lower than the determination temperature, the clogging due to frost formation of the heat exchange fins 22b occurs in the use side heat exchanger 22. Judgment is made and defrost operation is executed (step S4).

  Specifically, in this defrosting operation, the control unit 18 performs switching control of the four-way switching valve 16, and the refrigerant circulation direction in the refrigerant circuit is switched in the reverse direction. As a result, as shown in FIG. 3, the refrigerant discharged from the discharge portion 8 a of the compressor 8 is introduced into the use side heat exchanger 22 through the four-way switching valve 16, and the use side heat exchanger 22. Then, the refrigerant flows so as to return to the suction portion 8b of the compressor 8 through the expansion valve 14 and the heat source side heat exchanger 10 in order. Thereby, the use side heat exchanger 22 is warmed by the high-temperature refrigerant, and the heat exchange fins 22b and the heat transfer tubes 22a are defrosted. Then, when the defrosting is completed, the control unit 18 repeatedly performs the above-described series of flows.

  As described above, in the present embodiment, when the use side heat exchanger 22 is clogged, the evaporation rate of the refrigerant in the use side heat exchanger 22 is lowered during the cooling operation, and the evaporation rate of the refrigerant is reduced. As a result, the refrigerant pressure on the suction side of the compressor 8 during the cooling operation decreases. In the present embodiment, the pressure drop of the refrigerant is detected by the pressure sensor 26, and based on this, the use side heat exchanger 22 is clogged, that is, the heat exchange fins 22b are clogged or attached to the use side heat exchanger 22. It is possible to detect clogging of the air filter.

  Further, in the present embodiment, the use-side heat exchanger 22 is clogged by diverting the pressure detection by the pressure sensor 26 that is performed to monitor whether or not the refrigerant containing droplets of a predetermined ratio or more is sucked into the compressor 8. Since it can be detected, clogging of the use side heat exchanger 22 can be detected without particularly increasing the number of detection means and control means for clogging detection. Therefore, in the air conditioner according to the present embodiment, it is possible to detect clogging of the use side heat exchanger 22 while suppressing the configuration from becoming complicated.

  Moreover, in this embodiment, since the control part 18 detects clogging of the utilization side heat exchanger 22 based on the detection pressure of the pressure sensor 26 falling below the predetermined threshold value, Clogging of the use-side heat exchanger 22 can be determined based on the determination criterion that the detected pressure is lower than a predetermined threshold value. For this reason, the clogging of the use side heat exchanger 22 can be detected more accurately.

  Further, in the present embodiment, when the use side heat exchanger 22 is clogged, the temperature of the refrigerant after leaving the use side heat exchanger 22 does not increase so much during the cooling operation. Sometimes the difference in refrigerant temperature before being introduced into the use side heat exchanger 22 during the cooling operation with respect to the temperature of the refrigerant after leaving the use side heat exchanger 22, that is, the refrigerant before and after the use side heat exchanger 22 The temperature difference becomes smaller. Thereby, since the difference of the detected temperature of the 1st refrigerant | coolant temperature sensor 28 with respect to the detected temperature of the 2nd refrigerant | coolant temperature sensor 30 becomes small, based on that the detected temperature difference became small in this embodiment, a utilization side heat exchanger It is possible to detect clogging 22, that is, clogging of the heat exchange fins 22 b or clogging of the air filter attached to the use side heat exchanger 22.

  Furthermore, in the present embodiment, the first refrigerant temperature sensor 28 and the second refrigerant temperature sensor 30 that are used to monitor whether or not the evaporation of the refrigerant in the use side heat exchanger 22 is normally performed during the cooling operation are used. Since the detection of the temperature difference of the refrigerant before and after the use-side heat exchanger 22 can be diverted to detect clogging of the use-side heat exchanger 22, detection means and control means are particularly used for clogging detection. Clogging of the use-side heat exchanger 22 can be detected without increasing it. Therefore, in the air conditioner according to the present embodiment, it is possible to detect clogging of the use side heat exchanger 22 while suppressing the configuration from becoming complicated.

  In the present embodiment, the control unit 18 uses the user side based on the difference between the detected temperature of the first refrigerant temperature sensor 28 and the detected temperature of the second refrigerant temperature sensor 30 being smaller than a predetermined threshold value. Since the clogging of the heat exchanger 22 is detected, the fact that the difference between the detected temperature of the first refrigerant temperature sensor 28 and the detected temperature of the second refrigerant temperature sensor 30 has become smaller than a predetermined threshold is used as a criterion. The clogging of the side heat exchanger 22 can be determined. For this reason, the clogging of the use side heat exchanger 22 can be detected more accurately.

  Moreover, in this embodiment, after the control part 18 detects clogging of the utilization side heat exchanger 22, when the temperature detected by the utilization side heat exchanger temperature sensor 32 is equal to or higher than a predetermined determination temperature, the utilization side heat is increased. While it is determined that the clogging of the exchanger 22 is due to dust, when the temperature detected by the use side heat exchanger temperature sensor 32 is lower than the predetermined determination temperature, there are a plurality of clogs of the use side heat exchanger 22. It is determined that the heat exchange fin 22b is frosted. For this reason, it is possible to reliably determine whether the cause of the clogging of the use side heat exchanger 22 detected by the control unit 18 is due to dust or frost formation on the heat exchange fins 22b.

  In the present embodiment, when the control unit 18 determines that the clogging of the use side heat exchanger 22 is caused by dust, a remote controller capable of displaying the clogging of the use side heat exchanger 22 is possible. 6, when the user side heat exchanger 22 is clogged with dust, the clogging display of the remote controller 6 can cause the user to recognize the clogging of the user side heat exchanger 22. .

  Moreover, in this embodiment, when the control part 18 judges that clogging of the use side heat exchanger 22 is due to frost formation of the plurality of heat exchange fins 22b, the defrost operation is executed. For this reason, even when the clogging of the heat exchange fins 22b due to frost formation is detected, the heat exchange fins 22b can be defrosted by the defrosting operation to eliminate the clogging of the heat exchange fins 22b.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

  In the above embodiment, the detected pressure of the pressure sensor 26 has dropped below a predetermined threshold value, or the difference between the detected temperature of the first refrigerant temperature sensor 28 and the detected temperature of the second refrigerant temperature sensor 30. Although the clogging of the use side heat exchanger 22 is detected based on the fact that is smaller than a predetermined threshold value set in advance, the present invention is not limited to this configuration.

  For example, the detected pressure of the pressure sensor 26 monitored by the control unit 18 has decreased by a certain fluctuation rate or the first detected temperature of the second refrigerant temperature sensor 30 monitored by the control unit 18. The clogging of the use-side heat exchanger 22 may be detected based on the difference in the detected temperature of the refrigerant temperature sensor 28 being reduced at a certain fluctuation rate.

  Further, the control unit 18 uses only one of the detected pressure Lp of the pressure sensor 26 and the difference SH of the detected temperature of the first refrigerant temperature sensor 28 with respect to the detected temperature of the second refrigerant temperature sensor 30 as a determination criterion. The clogging of the exchanger 22 is detected, and the other may not be used for detecting the clogging of the use side heat exchanger 22.

  Further, when the control unit 18 detects clogging due to dust in the use side heat exchanger 22, the clogging is displayed not only in the display unit 6a of the remote controller 6 as in the above embodiment, but also in the indoor unit. The occurrence of clogging may be displayed on the display device provided in 4 or other various display devices.

It is the fluid circuit diagram which showed the structure of the air conditioner by one Embodiment of this invention. It is the figure which showed schematically the structure of the utilization side heat exchanger in FIG. It is the fluid circuit diagram which showed the state at the time of the defrost driving | operation of the air conditioner shown in FIG. It is a flowchart for demonstrating the operation | movement at the time of detecting clogging of a utilization side heat exchanger in the air conditioner by one Embodiment of this invention.

Explanation of symbols

6 Remote controller (display device)
8 Compressor 10 Heat source side heat exchanger 14 Expansion valve (expansion mechanism)
18 Control unit 22 Use side heat exchanger 22b Heat exchange fin 26 Pressure sensor 28 First refrigerant temperature sensor 30 Second refrigerant temperature sensor 32 Use side heat exchanger temperature sensor

Claims (7)

In an air conditioner including a refrigerant circuit in which a compressor, a heat source side heat exchanger, an expansion mechanism, and a use side heat exchanger are sequentially connected,
A pressure sensor for detecting the pressure of the refrigerant on the suction side of the compressor during cooling operation;
An air conditioner comprising: a control unit that detects clogging of the use side heat exchanger during cooling operation based on a pressure detected by the pressure sensor.   The air conditioner according to claim 1, wherein the control unit detects clogging of the use-side heat exchanger based on a detection pressure of the pressure sensor being lower than a predetermined threshold value. In an air conditioner including a refrigerant circuit in which a compressor, a heat source side heat exchanger, an expansion mechanism, and a use side heat exchanger are sequentially connected,
A first refrigerant temperature sensor for detecting a temperature of the refrigerant before being introduced into the use side heat exchanger during cooling operation;
A second refrigerant temperature sensor for detecting the temperature of the refrigerant after it has exited from the use side heat exchanger during cooling operation;
A control unit that calculates a difference between the detected temperature of the first refrigerant temperature sensor with respect to the detected temperature of the second refrigerant temperature sensor, and detects clogging of the use side heat exchanger based on the calculated difference of the detected temperature. And an air conditioner.   The air conditioner according to claim 3, wherein the control unit detects clogging of the use side heat exchanger based on the difference between the calculated detected temperatures being smaller than a predetermined threshold value. A user-side heat exchanger temperature sensor that detects the user-side heat exchanger temperature is provided.
The utilization side heat exchanger has a plurality of heat exchange fins,
After detecting the clogging of the use side heat exchanger, the control unit clogs the use side heat exchanger when the temperature detected by the use side heat exchanger temperature sensor is equal to or higher than a predetermined determination temperature. On the other hand, when the temperature detected by the usage-side heat exchanger temperature sensor is lower than the predetermined determination temperature, clogging of the usage-side heat exchanger is caused by frosting of the plurality of heat exchange fins. The air conditioner according to any one of claims 1 to 4, wherein the air conditioner is determined to be.   When the control unit determines that the clogging of the use side heat exchanger is caused by dust, the control unit includes a display device capable of displaying the clogging of the use side heat exchanger. The air conditioner described.   The air according to claim 5 or 6, wherein the control unit performs a defrost operation when it is determined that the clogging of the use side heat exchanger is due to frost formation of the plurality of heat exchange fins. Harmony machine.

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