JP2008164181A - Heat pump system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem caused by remaining frost in an outdoor heat exchanger of an air conditioner. <P>SOLUTION: An operation is switched to a heating operation when a defrosting operation is continued by a defrosting operation guard time, and a heating operation guard time is shortened to 0 in the heating operation after the defrosting operation where an outdoor heat exchange temperature is not more than a target heat exchange temperature during the lapse of the defrosting operation guard time. Accordingly, the operation is switched to the defrosting operation when the outdoor heat exchange temperature becomes lower than a defrosting operation starting temperature even before the heating operation guard time has not passed from the start of the heating operation in the heating operation after the defrosting operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air conditioner including an outdoor heat exchanger that serves as an evaporator during heating operation.

In an air conditioner, a phenomenon (frosting phenomenon) occurs in which moisture in the air becomes frost and adheres to an outdoor heat exchanger serving as an evaporator during heating operation. And if the amount of frost formation which adheres to an outdoor heat exchanger increases during heating operation, the ventilation resistance of an outdoor heat exchanger will increase and it will become difficult to maintain predetermined heating capacity. Therefore, when the amount of frost formation in the outdoor heat exchanger increases to a predetermined amount, a defrosting operation for removing frost attached to the outdoor heat exchanger is performed. Here, it is desirable that the defrosting operation is continued until the frost adhered to the outdoor heat exchanger is completely removed, but it may take a very long time under a condition where the outside air temperature is low. In such a case, in order to prevent the defrosting operation from continuing for a long time and not easily switching to the heating operation, in the air conditioner, the defrosting operation removes the frost attached to the outdoor heat exchanger to some extent. It is common to end the operation for a predetermined time and forcibly switch to the heating operation (see, for example, Patent Document 1).
JP-A-11-83117

  However, when the defrosting operation is forcibly switched to the heating operation, the frost attached to the outdoor heat exchanger is not completely removed, and residual frost is generated in the outdoor heat exchanger. Therefore, the heating operation after the defrosting operation is started in a state where residual frost is generated in the outdoor heat exchanger. Therefore, if heating operation is continued as it is, frost adheres to the outdoor heat exchanger, so that the frost attached to the outdoor heat exchanger cannot be completely removed in the normal defrosting operation. As a result, the heating operation capacity is significantly reduced, and in some cases, frost adhering to the outdoor heat exchanger freezes, and the outdoor heat exchanger cannot be used at all, or gas leakage due to pipe rupture occurs. There is.

  Then, the main objective of this invention is to provide the air conditioner which can eliminate the problem resulting from the residual frost in an outdoor heat exchanger.

  An air conditioner according to a first aspect of the present invention is an air conditioner including an indoor heat exchanger, an outdoor heat exchanger, a compressor, and a pressure reducing mechanism, and a predetermined lower limit time from the start of heating operation. When the temperature detected by the temperature sensor disposed in the outdoor heat exchanger during the heating operation becomes equal to or lower than the defrosting operation start temperature, the defrosting operation is switched to, and the temperature during the defrosting operation is switched to When the temperature detected by the sensor is equal to or higher than the defrosting operation release temperature or when the defrosting operation is continued for a predetermined upper limit time, the operation is switched to the heating operation, and the defrosting operation is continued for the predetermined upper limit time. Thus, when switching to heating operation, the predetermined lower limit time is shortened.

  In this air conditioner, when the defrosting operation is switched to the heating operation by continuing for a predetermined upper limit time, the defrosting in the outdoor heat exchanger is not completely completed (or insufficient). In the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened. Therefore, in the heating operation after the defrosting operation, the operation is easily switched to the defrosting operation, and the operation is switched to the defrosting operation with a relatively small amount of frost formation in the outdoor heat exchanger. Therefore, it is possible to prevent the heating operation capacity from being significantly reduced, and the frost attached to the outdoor heat exchanger is frozen, so that the outdoor heat exchanger cannot be used at all or gas leakage due to pipe rupture occurs. Can be prevented.

  An air conditioner according to a second aspect of the present invention is the air conditioner according to the first aspect of the present invention, wherein when the defrosting operation is continued for the predetermined upper limit time and switched to the heating operation, the predetermined lower limit time is reached. Is shortened to zero.

  In this air conditioner, during the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened to 0, regardless of the duration of the heating operation. The heating operation is switched to the defrosting operation only when the temperature detected by the temperature sensor arranged in the outdoor heat exchanger is equal to or lower than the defrosting operation start temperature. Therefore, in the heating operation after the defrosting operation, it becomes easier to switch to the defrosting operation, and the operation is switched to the defrosting operation with a small amount of frost on the outdoor heat exchanger.

  An air conditioner according to a third invention is the air conditioner according to the first or second invention, wherein the defrosting state in the outdoor heat exchanger when the defrosting operation is continued for the predetermined upper limit time is predetermined. In the defrosting state, the predetermined lower limit time is not shortened.

  Here, the “predetermined defrosting state” indicates a state in which the defrosting in the outdoor heat exchanger is not completely completed but the defrosting in the outdoor heat exchanger is almost completed. Therefore, when the defrosting state in the outdoor heat exchanger is the predetermined defrosting state, it is considered that the residual frost in the outdoor heat exchanger hardly affects the heating operation.

  In this air conditioner, even when the defrosting operation is continued for a predetermined upper limit time and switched to the heating operation, if it can be determined that the defrosting in the outdoor heat exchanger is almost completed, During the heating operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is not shortened. Therefore, since it becomes easy to switch to the defrosting operation in the heating operation after the defrosting operation, it is possible to suppress the time during which the heating operation is continued from being shortened.

  An air conditioner according to a fourth aspect of the present invention is the air conditioner according to the third aspect of the present invention, wherein the predetermined defrosting state is a target in which the temperature detected by the temperature sensor is lower than the defrosting operation release temperature. It is the state which becomes more than heat exchange temperature.

  In this air conditioner, the state in which the defrosting in the outdoor heat exchanger is almost completed can be easily determined based on the temperature detected by the temperature sensor arranged in the outdoor heat exchanger.

  The air conditioner according to the fifth invention is the air conditioner according to any one of the first to fourth inventions, and does not switch to the defrosting operation until a predetermined minimum time has elapsed from the start of the heating operation. It is characterized by.

  In this air conditioner, since it does not switch to the defrosting operation until the predetermined minimum time has elapsed since the start of the heating operation, the heating operation is continued by switching to the defrosting operation in a short time after the heating operation starts. It is possible to suppress the time from being shortened.

  An air conditioner according to a sixth invention is the air conditioner according to any one of the first to fourth inventions, wherein the defrosting operation start temperature until a predetermined time elapses from the start of the heating operation is It is characterized by being set lower than the defrosting operation start temperature after a predetermined time has elapsed.

  In this air conditioner, it is difficult to switch to the defrosting operation until a predetermined time elapses from the start of the heating operation. Therefore, the heating operation is continued by switching to the defrosting operation in a short time after the heating operation starts. It is possible to suppress the time from being shortened.

  As described above, according to the present invention, the following effects can be obtained.

  In the first invention, when the defrosting operation is switched to the heating operation by continuing for the predetermined upper limit time, the defrosting in the outdoor heat exchanger is not completely completed (or insufficient). In the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened. Therefore, in the heating operation after the defrosting operation, the operation is easily switched to the defrosting operation, and the operation is switched to the defrosting operation with a relatively small amount of frost formation in the outdoor heat exchanger. Therefore, it is possible to prevent the heating operation capacity from being significantly reduced, and the frost attached to the outdoor heat exchanger is frozen, so that the outdoor heat exchanger cannot be used at all or gas leakage due to pipe rupture occurs. Can be prevented.

  In the second invention, during the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened to 0, regardless of the duration of the heating operation. The heating operation is switched to the defrosting operation only when the temperature detected by the temperature sensor arranged in the outdoor heat exchanger is equal to or lower than the defrosting operation start temperature. Therefore, in the heating operation after the defrosting operation, it becomes easier to switch to the defrosting operation, and the operation is switched to the defrosting operation with a small amount of frost formation on the outdoor heat exchanger.

  In 3rd invention, even when it switches to heating operation because defrost operation continues only for predetermined upper limit time, when it can be judged that defrost in an outdoor heat exchanger is almost completed, after defrost operation During the heating operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is not shortened. Therefore, since it becomes easy to switch to the defrosting operation in the heating operation after the defrosting operation, it is possible to suppress the time during which the heating operation is continued from being shortened.

  In 4th invention, the state which the defrosting in an outdoor heat exchanger has completed substantially can be judged easily based on the detected temperature with the temperature sensor arrange | positioned at the outdoor heat exchanger.

  In 5th invention, since it does not switch to defrost operation until predetermined minimum time passes since the heating operation start, heating operation is continued by switching to defrost operation for a short time after heating operation start. It is possible to suppress the time from being shortened.

  In 6th invention, since it becomes difficult to switch to defrosting operation until predetermined time passes since heating operation start, heating operation is continued by switching to defrosting operation for a short time after heating operation start. It is possible to suppress the time from being shortened.

  Hereinafter, embodiments of an air conditioner according to the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of an air conditioner according to an embodiment of the present invention.

  In the refrigerant circuit diagram of the air conditioner 10 of FIG. 1, the primary port of the four-way switching valve 5 is connected between the discharge side and the suction side of the compressor 3 that is controlled to be variable in compression capacity by an inverter. . And between the secondary ports of the four-way switching valve 5, the first gas pipe 6, the outdoor heat exchanger 2, the first liquid pipe 7, the electric expansion valve 4, the second liquid pipe 8, the indoor heat exchanger 1, The second gas pipe 9 is connected in order.

  Here, by switching the four-way switching valve 5 in the direction of the solid line, the cooling operation can be performed by causing the outdoor heat exchanger 2 to function as a condenser and the indoor heat exchanger 1 to function as an evaporator. On the other hand, by switching the four-way switching valve 5 in the direction of the broken line, the outdoor heat exchanger 2 can function as an evaporator and the indoor heat exchanger 1 can function as a condenser. In the air conditioner 10, the four-way switching valve 5 can be switched from the heating operation to the defrosting operation by switching the four-way switching valve 5 from the broken line direction to the solid line direction during the heating operation. Can be switched from the defrosting operation to the heating operation by switching from the solid line direction to the broken line direction.

  Next, the configuration of the control unit of the air conditioner 10 of the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing a configuration of a control unit of the air conditioner of FIG.

  The control unit 30 includes an operation setting storage unit 31, a heating operation timer 32, a defrosting operation timer 33, and a control unit 34. The control unit 30 is connected to an outdoor heat exchanger temperature sensor 41 disposed in the outdoor heat exchanger 2 and the four-way switching valve 5. In the present embodiment, the outdoor heat exchange temperature sensor 41 is arranged at an intermediate position of the outdoor heat exchanger 2, but the arrangement can be changed.

  The operation setting storage unit 31 stores various operation settings related to the air conditioner 10. The operation setting stored in the operation setting storage unit 31 includes the minimum guard time (for example, 6 minutes) that is the minimum duration of the heating operation and until it becomes possible to switch to the defrosting operation during the normal heating operation. Heating operation guard time (for example, 30 minutes), defrosting operation guard time (for example, 10 minutes) until the defrosting operation is forcibly switched to heating operation, and heating operation to defrosting operation When defrosting operation start temperature (for example, temperature represented by a relational expression including variables relating to the outside air temperature and the operating frequency of the compressor), which is the outdoor heat exchange temperature when switching to, and when switching from defrosting operation to heating operation The defrosting operation cancellation temperature (for example, the temperature represented by a relational expression including a variable related to the outside air temperature) that is the temperature of the outdoor heat exchanger and the target that is the outdoor heat exchange temperature when the defrosting in the outdoor heat exchanger 2 is almost completed Exchanger temperature (e.g. than the defrosting operation canceling temperature 2 to 3 ° C. lower temperature) are included and are.

  The heating operation timer 32 measures the time during which the heating operation is performed, and is returned to 0 each time the heating operation is completed (every time the operation is switched to the defrosting operation or the cooling operation). The defrosting operation timer 33 measures the time during which the defrosting operation is performed, and is reset to 0 each time the defrosting operation is completed (every time the operation is switched to the heating operation).

  The control unit 34 controls the operating state of the air conditioner 10 by switching the refrigerant path of the four-way switching valve 5. Specifically, the control unit 34 switches the operation state of the air conditioner 10 from, for example, the heating operation to the defrosting operation and the switching from the defrosting operation to the heating operation.

  In the normal heating operation, the control unit 34 performs the defrosting operation when the outdoor heat exchange temperature becomes equal to or lower than the defrosting operation start temperature after the heating operation guard time has elapsed from the start of the heating operation. Switch to. Here, the normal heating operation refers to a heating operation after the start of the heating operation and before switching to the defrosting operation, and heating when the outdoor heat exchange temperature becomes equal to or higher than the defrosting operation release temperature during the defrosting operation. Heating operation after defrosting operation when switched to operation, and defrosting operation continues for defrosting operation guard time, switching to heating operation, and outdoor heat exchange temperature when defrosting operation guard time elapses is the target The heating operation after the defrosting operation when the temperature is equal to or higher than the heat exchange temperature is shown.

  Further, the control unit 34 defrosts when the defrosting operation is switched to the heating operation by continuing the defrosting operation guard time and the outdoor heat exchange temperature when the defrosting operation guard time elapses is not equal to or higher than the target heat exchange temperature. When the outdoor heat exchange temperature becomes equal to or lower than the defrosting operation start temperature during the heating operation after the operation, the heating operation is switched to the defrosting operation.

  Further, the control unit 34 changes from the defrosting operation to the heating operation when the outdoor heat exchange temperature becomes equal to or higher than the defrosting operation release temperature during the defrosting operation and when the defrosting operation is continued for the defrosting operation guard time. Switch.

  In the present embodiment, the control unit 34 does not switch from the heating operation to the defrosting operation until the minimum guard time has elapsed from the start of the heating operation.

  Next, the operation | movement procedure at the time of the heating operation of the air conditioner 10 of this Embodiment is demonstrated with reference to FIG. FIG. 3 is a flowchart showing an operation procedure during the heating operation of the air conditioner of the present embodiment.

  First, when the operation for starting the heating operation is performed by the user, the heating operation is started, and at the same time, measurement by the heating operation timer 32 is started (step S1). Then, it is repeatedly determined whether or not the minimum guard time has elapsed since the start of the heating operation (whether or not the measurement time in the heating operation timer 32 has passed the minimum guard time) (step S2). Here, when the minimum guard time has elapsed since the start of the heating operation (S2: YES), whether the heating operation guard time has elapsed since the start of the heating operation (the time measured by the heating operation timer 32 is the heating time). Whether or not the driving guard time has passed is repeatedly determined (step S3).

  When the heating operation guard time has elapsed since the start of the heating operation (S3: YES), the outdoor heat exchange temperature detected by the outdoor heat exchange temperature sensor 41 is equal to or lower than the defrosting operation start temperature during the heating operation. Is repeatedly determined (step S4). Here, when the outdoor heat exchange temperature is equal to or lower than the defrosting operation start temperature (S4: YES), the measurement by the defrosting operation timer 33 is started simultaneously with switching from the heating operation to the defrosting operation (step) S5). Then, during the defrosting operation, it is repeatedly determined whether or not the outdoor heat exchange temperature is equal to or higher than the defrosting operation release temperature (step S6). When the outdoor heat exchange temperature is equal to or higher than the defrosting operation release temperature (S6: YES), the defrosting operation is switched to the heating operation, and then the process returns to step S2 and the same processing as described above is repeated. That is, in the heating operation after the defrosting operation in this case, it is possible to switch to the defrosting operation after the heating operation guard time has elapsed from the start of the heating operation, and the heating operation guard time from the start of the heating operation. It will not be switched to the defrosting operation until has passed.

  In step S6, if the outdoor heat exchange temperature is not equal to or higher than the defrosting operation release temperature (S6: NO), whether or not the defrosting operation guard time has elapsed since the start of the defrosting operation (in the defrosting operation timer 33). Whether or not the measurement time of the defrosting operation guard time has elapsed is repeatedly determined (step S8). If the defrosting operation guard time has elapsed since the start of the defrosting operation (S8: YES), it is repeatedly determined whether or not the outdoor heat exchange temperature is equal to or higher than the target heat exchange temperature during the defrosting operation. (Step S9).

  Here, when the outdoor heat exchange temperature is equal to or higher than the target heat exchange temperature (S9: YES), the process proceeds to step S7, the defrosting operation is switched to the heating operation, and then the process returns to step S2 and is the same as described above. The process is repeated. That is, in the heating operation after the defrosting operation in this case, it is possible to switch to the defrosting operation after the heating operation guard time has elapsed from the start of the heating operation, and the heating operation guard time from the start of the heating operation. It will not be switched to the defrosting operation until has passed.

  On the other hand, when the outdoor heat exchange temperature is not equal to or higher than the target heat exchange temperature (S9: NO), the process proceeds to step S10, and the defrosting operation is switched to the heating operation. Thereafter, whether or not the minimum guard time has elapsed since the start of the heating operation after the defrosting operation (whether or not the measurement time in the heating operation timer 32 has passed the minimum guard time) is repeatedly determined (step S11). . Here, when the minimum guard time has elapsed from the start of the heating operation after the defrosting operation (S11: YES), the process returns to step S4 and the same processing as described above is repeated. That is, in the heating operation after the defrosting operation in this case, if the heating operation time has passed the minimum guard time, the heating operation is switched to the defrosting operation even after the heating operation guard time has elapsed from the start of the heating operation. It is possible to change.

  In step S8, when the defrosting operation guard time has not elapsed since the start of the defrosting operation (S8: NO), the process returns to step S6 and the same processing as described above is repeated.

  As described above, in the air conditioner 10 of the present embodiment, the defrosting operation is switched to the heating operation by continuing the defrosting operation guard time, and the outdoor heat exchange temperature when the defrosting operation guard time elapses is set. In the heating operation after the defrosting operation when the temperature is not equal to or higher than the target heat exchange temperature, the defrosting in the outdoor heat exchanger 2 in the defrosting operation is not completely completed (or insufficient), so the heating operation guard time Is reduced to zero. Therefore, in the heating operation after the defrosting operation, even if it is before the heating operation guard time elapses from the start of the heating operation, the outdoor heat exchange temperature is switched to the defrosting operation only at or below the defrosting operation start temperature. Since it becomes possible and it becomes easy to switch to a defrosting operation, it switches to a defrosting operation in the state where there is little frost formation amount to an outdoor heat exchanger. Therefore, it is possible to prevent the heating operation capacity from being significantly reduced, and the frost attached to the outdoor heat exchanger is frozen, so that the outdoor heat exchanger cannot be used at all or gas leakage due to pipe rupture occurs. Can be prevented.

  Even if the defrosting operation is switched to the heating operation by continuing the defrosting operation guard time, if the outdoor heat exchange temperature after the defrosting operation guard time has exceeded the target heat exchange temperature, the outdoor It is determined that the defrosting in the heat exchanger is almost completed, and the heating operation guard time is not shortened. Therefore, since it becomes easy to switch to the defrosting operation in the heating operation after the defrosting operation, it is possible to suppress the time during which the heating operation is continued from being shortened.

  In addition, since the defrosting operation is not switched until the minimum guard time has elapsed since the start of the heating operation, the time for which the heating operation is continued is shortened by switching to the defrosting operation in a short time after the heating operation is started. Can be suppressed.

  As mentioned above, although embodiment of this invention was described based on drawing, specific structure is not restricted to these embodiment, It can change in the range which does not deviate from the summary of invention.

  In the above-described embodiment, the defrosting operation is switched to the heating operation by continuing the defrosting operation for the defrosting operation guard time, and the outdoor heat exchange temperature when the defrosting operation guard time elapses is not equal to or higher than the target heat exchange temperature. In the heating operation after the operation, the heating operation guard time is shortened to 0, but the heating operation guard time may be shortened from the original time to a time other than 0. Further, the heating operation guard time may be shortened to 0 regardless of whether the outdoor heat exchange temperature when the defrost operation guard time elapses is equal to or higher than the target heat exchange temperature.

  In the above-described embodiment, after the minimum guard time has elapsed from the start of the heating operation, it is possible to switch from the heating operation to the defrosting operation, but a predetermined time has elapsed from the start of the heating operation. The defrosting operation start temperature until may be set lower than the subsequent defrosting operation start temperature. In this case, since it becomes difficult to switch to the defrosting operation until a predetermined time has elapsed from the start of the heating operation, the time for which the heating operation is continued by switching to the defrosting operation in a short time after the heating operation starts. Shortening can be suppressed.

  In the above-described embodiment, it is determined that the defrosting in the outdoor heat exchanger is almost completed when the outdoor heat exchange temperature when the defrosting operation guard time elapses is equal to or higher than the target heat exchange temperature. By this method, it may be determined that the defrosting in the outdoor heat exchanger is almost completed.

  By using the present invention, it is possible to suppress a significant decrease in heating operation capacity, and the frost adhering to the outdoor heat exchanger freezes, so that the outdoor heat exchanger cannot be used at all, or a gas leak due to a pipe rupture. Can be prevented.

It is a refrigerant circuit figure of the air conditioner concerning an embodiment of the invention. It is a block diagram which shows the structure of the control unit of the air conditioner of FIG. It is a flowchart which shows the operation | movement procedure at the time of the heating operation of the air conditioner of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Indoor heat exchanger 2 Outdoor heat exchanger 3 Compressor 4 Electric expansion valve 10 Air conditioner 30 Control unit 31 Operation setting memory | storage part 32 Heating operation timer 33 Defrosting operation timer 34 Control part 41 Outdoor heat exchanger temperature sensor

The present invention relates to a heat pump system including an outdoor heat exchanger that serves as an evaporator during heating operation.

In an air conditioner (heat pump system) , a phenomenon (frosting phenomenon) occurs in which moisture in the air becomes frost and adheres to an outdoor heat exchanger serving as an evaporator during heating operation. And if the amount of frost formation which adheres to an outdoor heat exchanger increases during heating operation, the ventilation resistance of an outdoor heat exchanger will increase and it will become difficult to maintain predetermined heating capacity. Therefore, when the amount of frost formation in the outdoor heat exchanger increases to a predetermined amount, a defrosting operation for removing frost attached to the outdoor heat exchanger is performed. Here, it is desirable that the defrosting operation is continued until the frost adhered to the outdoor heat exchanger is completely removed, but it may take a very long time under a condition where the outside air temperature is low. In such a case, in order to prevent the defrosting operation from continuing for a long time and not easily switching to the heating operation, in the air conditioner, the defrosting operation removes the frost attached to the outdoor heat exchanger to some extent. It is common to end the operation for a predetermined time and forcibly switch to the heating operation (see, for example, Patent Document 1).
JP-A-11-83117

  However, when the defrosting operation is forcibly switched to the heating operation, the frost attached to the outdoor heat exchanger is not completely removed, and residual frost is generated in the outdoor heat exchanger. Therefore, the heating operation after the defrosting operation is started in a state where residual frost is generated in the outdoor heat exchanger. Therefore, if heating operation is continued as it is, frost adheres to the outdoor heat exchanger, so that the frost attached to the outdoor heat exchanger cannot be completely removed in the normal defrosting operation. As a result, the heating operation capacity is significantly reduced, and in some cases, frost adhering to the outdoor heat exchanger freezes, and the outdoor heat exchanger cannot be used at all, or gas leakage due to pipe rupture occurs. There is.

Then, the main objective of this invention is to provide the heat pump system which can eliminate the problem resulting from the residual frost in an outdoor heat exchanger.

The heat pump system according to the first invention, an indoor heat exchanger, an outdoor heat exchanger, a compressor, a heat pump system and a vacuum mechanism, the predetermined lower limit time has elapsed from the start of the heating operation In addition, when the temperature detected by the temperature sensor disposed in the outdoor heat exchanger during the heating operation becomes equal to or lower than the defrosting operation start temperature, the defrosting operation is switched, and during the defrosting operation, the temperature sensor When the detected temperature is equal to or higher than the defrosting operation release temperature or when the defrosting operation is continued for a predetermined upper limit time, the operation is switched to the heating operation, and the defrosting operation is continued for the predetermined upper limit time. The predetermined lower limit time is shortened when switching to heating operation.

In this heat pump system , when the defrosting operation is continued for a predetermined upper limit time and switched to the heating operation, it is determined that the defrosting in the outdoor heat exchanger is not completely completed (or insufficient). In the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened. Therefore, in the heating operation after the defrosting operation, the operation is easily switched to the defrosting operation, and the operation is switched to the defrosting operation with a relatively small amount of frost formation in the outdoor heat exchanger. Therefore, it is possible to prevent the heating operation capacity from being significantly reduced, and the frost attached to the outdoor heat exchanger is frozen, so that the outdoor heat exchanger cannot be used at all or gas leakage due to pipe rupture occurs. Can be prevented.

The heat pump system according to a second invention is a heat pump system according to the first invention, the predetermined lower limit time when the defrosting operation is switched to the heating operation by continuing for the predetermined upper limit time 0 It is characterized by being shortened.

In this heat pump system , during the heating operation after the defrosting operation, since the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is reduced to 0, regardless of the duration of the heating operation, The heating operation is switched to the defrosting operation only when the temperature detected by the temperature sensor arranged in the outdoor heat exchanger is equal to or lower than the defrosting operation start temperature. Therefore, in the heating operation after the defrosting operation, it becomes easier to switch to the defrosting operation, and the operation is switched to the defrosting operation with a small amount of frost on the outdoor heat exchanger.

The heat pump system according to the third invention is a heat pump system according to the first or second invention, defrost predetermined defrosting in the outdoor heat exchanger when the defrosting operation is continued for the predetermined upper limit time In the state, the predetermined lower limit time is not shortened.

  Here, the “predetermined defrosting state” indicates a state in which the defrosting in the outdoor heat exchanger is not completely completed but the defrosting in the outdoor heat exchanger is almost completed. Therefore, when the defrosting state in the outdoor heat exchanger is the predetermined defrosting state, it is considered that the residual frost in the outdoor heat exchanger hardly affects the heating operation.

In this heat pump system , even when the defrosting operation is continued for a predetermined upper limit time and switched to the heating operation, when it can be determined that the defrosting in the outdoor heat exchanger is almost completed, During the heating operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is not shortened. Therefore, since it becomes easy to switch to the defrosting operation in the heating operation after the defrosting operation, it is possible to suppress the time during which the heating operation is continued from being shortened.

The heat pump system according to the fourth invention is a heat pump system according to the third invention, the predetermined defrost condition is low the target heat exchange even temperature than the defrosting operation canceling temperature detected by the temperature sensor It is characterized by being in a temperature higher than the temperature.

In this heat pump system , the state where the defrosting in the outdoor heat exchanger is almost completed can be easily determined based on the temperature detected by the temperature sensor arranged in the outdoor heat exchanger.

A heat pump system according to a fifth invention is the heat pump system according to any one of the first to fourth inventions, wherein the heat pump system does not switch to the defrosting operation until a predetermined minimum time has elapsed from the start of the heating operation. It is said.

In this heat pump system , since it does not switch to the defrosting operation until the predetermined minimum time has elapsed since the start of the heating operation, the time for which the heating operation is continued by switching to the defrosting operation in a short time after starting the heating operation. Can be suppressed.

Heat pump system according to a sixth aspect of the present invention, a heat pump system according to the first to fourth invention of any one of the defrosting operation starting temperature until a predetermined time has elapsed from the start of heating operation, the predetermined time Is set to be lower than the defrosting operation start temperature after elapse of time.

In this heat pump system , since it becomes difficult to switch to the defrosting operation until a predetermined time has elapsed from the start of the heating operation, the time for which the heating operation is continued by switching to the defrosting operation in a short time after the heating operation starts. Can be suppressed.

  As described above, according to the present invention, the following effects can be obtained.

  In the first invention, when the defrosting operation is switched to the heating operation by continuing for the predetermined upper limit time, the defrosting in the outdoor heat exchanger is not completely completed (or insufficient). In the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened. Therefore, in the heating operation after the defrosting operation, the operation is easily switched to the defrosting operation, and the operation is switched to the defrosting operation with a relatively small amount of frost formation in the outdoor heat exchanger. Therefore, it is possible to prevent the heating operation capacity from being significantly reduced, and the frost attached to the outdoor heat exchanger is frozen, so that the outdoor heat exchanger cannot be used at all or gas leakage due to pipe rupture occurs. Can be prevented.

  In the second invention, during the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened to 0, regardless of the duration of the heating operation. The heating operation is switched to the defrosting operation only when the temperature detected by the temperature sensor arranged in the outdoor heat exchanger is equal to or lower than the defrosting operation start temperature. Therefore, in the heating operation after the defrosting operation, it becomes easier to switch to the defrosting operation, and the operation is switched to the defrosting operation with a small amount of frost formation on the outdoor heat exchanger.

  In 3rd invention, even when it switches to heating operation because defrost operation continues only for predetermined upper limit time, when it can be judged that defrost in an outdoor heat exchanger is almost completed, after defrost operation During the heating operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is not shortened. Therefore, since it becomes easy to switch to the defrosting operation in the heating operation after the defrosting operation, it is possible to suppress the time during which the heating operation is continued from being shortened.

  In 4th invention, the state which the defrosting in an outdoor heat exchanger has completed substantially can be judged easily based on the detected temperature with the temperature sensor arrange | positioned at the outdoor heat exchanger.

  In 5th invention, since it does not switch to defrost operation until predetermined minimum time passes since the heating operation start, heating operation is continued by switching to defrost operation for a short time after heating operation start. It is possible to suppress the time from being shortened.

  In 6th invention, since it becomes difficult to switch to defrosting operation until predetermined time passes since heating operation start, heating operation is continued by switching to defrosting operation for a short time after heating operation start. It is possible to suppress the time from being shortened.

Hereinafter, embodiments of an air conditioner (heat pump system) according to the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of an air conditioner according to an embodiment of the present invention.

  In the refrigerant circuit diagram of the air conditioner 10 of FIG. 1, the primary port of the four-way switching valve 5 is connected between the discharge side and the suction side of the compressor 3 that is controlled to be variable in compression capacity by an inverter. . And between the secondary ports of the four-way switching valve 5, the first gas pipe 6, the outdoor heat exchanger 2, the first liquid pipe 7, the electric expansion valve 4, the second liquid pipe 8, the indoor heat exchanger 1, The second gas pipe 9 is connected in order.

  Here, by switching the four-way switching valve 5 in the direction of the solid line, the cooling operation can be performed by causing the outdoor heat exchanger 2 to function as a condenser and the indoor heat exchanger 1 to function as an evaporator. On the other hand, by switching the four-way switching valve 5 in the direction of the broken line, the outdoor heat exchanger 2 can function as an evaporator and the indoor heat exchanger 1 can function as a condenser. In the air conditioner 10, the four-way switching valve 5 can be switched from the heating operation to the defrosting operation by switching the four-way switching valve 5 from the broken line direction to the solid line direction during the heating operation. Can be switched from the defrosting operation to the heating operation by switching from the solid line direction to the broken line direction.

  Next, the configuration of the control unit of the air conditioner 10 of the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing a configuration of a control unit of the air conditioner of FIG.

  The control unit 30 includes an operation setting storage unit 31, a heating operation timer 32, a defrosting operation timer 33, and a control unit 34. The control unit 30 is connected to an outdoor heat exchanger temperature sensor 41 disposed in the outdoor heat exchanger 2 and the four-way switching valve 5. In the present embodiment, the outdoor heat exchange temperature sensor 41 is arranged at an intermediate position of the outdoor heat exchanger 2, but the arrangement can be changed.

  The operation setting storage unit 31 stores various operation settings related to the air conditioner 10. The operation setting stored in the operation setting storage unit 31 includes the minimum guard time (for example, 6 minutes) that is the minimum duration of the heating operation and until it becomes possible to switch to the defrosting operation during the normal heating operation. Heating operation guard time (for example, 30 minutes), defrosting operation guard time (for example, 10 minutes) until the defrosting operation is forcibly switched to heating operation, and heating operation to defrosting operation When defrosting operation start temperature (for example, temperature represented by a relational expression including variables relating to the outside air temperature and the operating frequency of the compressor), which is the outdoor heat exchange temperature when switching to, and when switching from defrosting operation to heating operation The defrosting operation cancellation temperature (for example, the temperature represented by a relational expression including a variable related to the outside air temperature) that is the temperature of the outdoor heat exchanger and the target that is the outdoor heat exchange temperature when the defrosting in the outdoor heat exchanger 2 is almost completed Exchanger temperature (e.g. than the defrosting operation canceling temperature 2 to 3 ° C. lower temperature) are included and are.

  The heating operation timer 32 measures the time during which the heating operation is performed, and is returned to 0 each time the heating operation is completed (every time the operation is switched to the defrosting operation or the cooling operation). The defrosting operation timer 33 measures the time during which the defrosting operation is performed, and is reset to 0 each time the defrosting operation is completed (every time the operation is switched to the heating operation).

  The control unit 34 controls the operating state of the air conditioner 10 by switching the refrigerant path of the four-way switching valve 5. Specifically, the control unit 34 switches the operation state of the air conditioner 10 from, for example, the heating operation to the defrosting operation and the switching from the defrosting operation to the heating operation.

  In the normal heating operation, the control unit 34 performs the defrosting operation when the outdoor heat exchange temperature becomes equal to or lower than the defrosting operation start temperature after the heating operation guard time has elapsed from the start of the heating operation. Switch to. Here, the normal heating operation refers to a heating operation after the start of the heating operation and before switching to the defrosting operation, and heating when the outdoor heat exchange temperature becomes equal to or higher than the defrosting operation release temperature during the defrosting operation. Heating operation after defrosting operation when switched to operation, and defrosting operation continues for defrosting operation guard time, switching to heating operation, and outdoor heat exchange temperature when defrosting operation guard time elapses is the target The heating operation after the defrosting operation when the temperature is equal to or higher than the heat exchange temperature is shown.

  Further, the control unit 34 defrosts when the defrosting operation is switched to the heating operation by continuing the defrosting operation guard time and the outdoor heat exchange temperature when the defrosting operation guard time elapses is not equal to or higher than the target heat exchange temperature. When the outdoor heat exchange temperature becomes equal to or lower than the defrosting operation start temperature during the heating operation after the operation, the heating operation is switched to the defrosting operation.

  Further, the control unit 34 changes from the defrosting operation to the heating operation when the outdoor heat exchange temperature becomes equal to or higher than the defrosting operation release temperature during the defrosting operation and when the defrosting operation is continued for the defrosting operation guard time. Switch.

  In the present embodiment, the control unit 34 does not switch from the heating operation to the defrosting operation until the minimum guard time has elapsed from the start of the heating operation.

  Next, the operation | movement procedure at the time of the heating operation of the air conditioner 10 of this Embodiment is demonstrated with reference to FIG. FIG. 3 is a flowchart showing an operation procedure during the heating operation of the air conditioner of the present embodiment.

  First, when the operation for starting the heating operation is performed by the user, the heating operation is started, and at the same time, measurement by the heating operation timer 32 is started (step S1). Then, it is repeatedly determined whether or not the minimum guard time has elapsed since the start of the heating operation (whether or not the measurement time in the heating operation timer 32 has passed the minimum guard time) (step S2). Here, when the minimum guard time has elapsed since the start of the heating operation (S2: YES), whether the heating operation guard time has elapsed since the start of the heating operation (the time measured by the heating operation timer 32 is the heating time). Whether or not the driving guard time has passed is repeatedly determined (step S3).

  When the heating operation guard time has elapsed since the start of the heating operation (S3: YES), the outdoor heat exchange temperature detected by the outdoor heat exchange temperature sensor 41 is equal to or lower than the defrosting operation start temperature during the heating operation. Is repeatedly determined (step S4). Here, when the outdoor heat exchange temperature is equal to or lower than the defrosting operation start temperature (S4: YES), the measurement by the defrosting operation timer 33 is started simultaneously with switching from the heating operation to the defrosting operation (step) S5). Then, during the defrosting operation, it is repeatedly determined whether or not the outdoor heat exchange temperature is equal to or higher than the defrosting operation release temperature (step S6). When the outdoor heat exchange temperature is equal to or higher than the defrosting operation release temperature (S6: YES), the defrosting operation is switched to the heating operation, and then the process returns to step S2 and the same processing as described above is repeated. That is, in the heating operation after the defrosting operation in this case, it is possible to switch to the defrosting operation after the heating operation guard time has elapsed from the start of the heating operation, and the heating operation guard time from the start of the heating operation. It will not be switched to the defrosting operation until has passed.

  In step S6, if the outdoor heat exchange temperature is not equal to or higher than the defrosting operation release temperature (S6: NO), whether or not the defrosting operation guard time has elapsed since the start of the defrosting operation (in the defrosting operation timer 33). Whether or not the measurement time of the defrosting operation guard time has elapsed is repeatedly determined (step S8). If the defrosting operation guard time has elapsed since the start of the defrosting operation (S8: YES), it is repeatedly determined whether or not the outdoor heat exchange temperature is equal to or higher than the target heat exchange temperature during the defrosting operation. (Step S9).

  Here, when the outdoor heat exchange temperature is equal to or higher than the target heat exchange temperature (S9: YES), the process proceeds to step S7, the defrosting operation is switched to the heating operation, and then the process returns to step S2 and is the same as described above. The process is repeated. That is, in the heating operation after the defrosting operation in this case, it is possible to switch to the defrosting operation after the heating operation guard time has elapsed from the start of the heating operation, and the heating operation guard time from the start of the heating operation. It will not be switched to the defrosting operation until has passed.

  On the other hand, when the outdoor heat exchange temperature is not equal to or higher than the target heat exchange temperature (S9: NO), the process proceeds to step S10, and the defrosting operation is switched to the heating operation. Thereafter, whether or not the minimum guard time has elapsed since the start of the heating operation after the defrosting operation (whether or not the measurement time in the heating operation timer 32 has passed the minimum guard time) is repeatedly determined (step S11). . Here, when the minimum guard time has elapsed from the start of the heating operation after the defrosting operation (S11: YES), the process returns to step S4 and the same processing as described above is repeated. That is, in the heating operation after the defrosting operation in this case, if the heating operation time has passed the minimum guard time, the heating operation is switched to the defrosting operation even after the heating operation guard time has elapsed from the start of the heating operation. It is possible to change.

  In step S8, when the defrosting operation guard time has not elapsed since the start of the defrosting operation (S8: NO), the process returns to step S6 and the same processing as described above is repeated.

  As described above, in the air conditioner 10 of the present embodiment, the defrosting operation is switched to the heating operation by continuing the defrosting operation guard time, and the outdoor heat exchange temperature when the defrosting operation guard time elapses is set. In the heating operation after the defrosting operation when the temperature is not equal to or higher than the target heat exchange temperature, the defrosting in the outdoor heat exchanger 2 in the defrosting operation is not completely completed (or insufficient), so the heating operation guard time Is reduced to zero. Therefore, in the heating operation after the defrosting operation, even if it is before the heating operation guard time elapses from the start of the heating operation, the outdoor heat exchange temperature is switched to the defrosting operation only at or below the defrosting operation start temperature. Since it becomes possible and it becomes easy to switch to a defrosting operation, it switches to a defrosting operation in the state where there is little frost formation amount to an outdoor heat exchanger. Therefore, it is possible to prevent the heating operation capacity from being significantly reduced, and the frost attached to the outdoor heat exchanger is frozen, so that the outdoor heat exchanger cannot be used at all or gas leakage due to pipe rupture occurs. Can be prevented.

  Even if the defrosting operation is switched to the heating operation by continuing the defrosting operation guard time, if the outdoor heat exchange temperature after the defrosting operation guard time has exceeded the target heat exchange temperature, the outdoor It is determined that the defrosting in the heat exchanger is almost completed, and the heating operation guard time is not shortened. Therefore, since it becomes easy to switch to the defrosting operation in the heating operation after the defrosting operation, it is possible to suppress the time during which the heating operation is continued from being shortened.

  In addition, since the defrosting operation is not switched until the minimum guard time has elapsed since the start of the heating operation, the time for which the heating operation is continued is shortened by switching to the defrosting operation in a short time after the heating operation is started. Can be suppressed.

  As mentioned above, although embodiment of this invention was described based on drawing, specific structure is not restricted to these embodiment, It can change in the range which does not deviate from the summary of invention.

  In the above-described embodiment, the defrosting operation is switched to the heating operation by continuing the defrosting operation for the defrosting operation guard time, and the outdoor heat exchange temperature when the defrosting operation guard time elapses is not equal to or higher than the target heat exchange temperature. In the heating operation after the operation, the heating operation guard time is shortened to 0, but the heating operation guard time may be shortened from the original time to a time other than 0. Further, the heating operation guard time may be shortened to 0 regardless of whether the outdoor heat exchange temperature when the defrost operation guard time elapses is equal to or higher than the target heat exchange temperature.

  In the above-described embodiment, after the minimum guard time has elapsed from the start of the heating operation, it is possible to switch from the heating operation to the defrosting operation, but a predetermined time has elapsed from the start of the heating operation. The defrosting operation start temperature until may be set lower than the subsequent defrosting operation start temperature. In this case, since it becomes difficult to switch to the defrosting operation until a predetermined time has elapsed from the start of the heating operation, the time for which the heating operation is continued by switching to the defrosting operation in a short time after the heating operation starts. Shortening can be suppressed.

  In the above-described embodiment, it is determined that the defrosting in the outdoor heat exchanger is almost completed when the outdoor heat exchange temperature when the defrosting operation guard time elapses is equal to or higher than the target heat exchange temperature. By this method, it may be determined that the defrosting in the outdoor heat exchanger is almost completed.

  By using the present invention, it is possible to suppress a significant decrease in heating operation capacity, and the frost adhering to the outdoor heat exchanger freezes, so that the outdoor heat exchanger cannot be used at all, or a gas leak due to a pipe rupture. Can be prevented.

It is a refrigerant circuit figure of the air conditioner concerning an embodiment of the invention. It is a block diagram which shows the structure of the control unit of the air conditioner of FIG. It is a flowchart which shows the operation | movement procedure at the time of the heating operation of the air conditioner of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Indoor heat exchanger 2 Outdoor heat exchanger 3 Compressor 4 Electric expansion valve 10 Air conditioner 30 Control unit 31 Operation setting memory | storage part 32 Heating operation timer 33 Defrosting operation timer 34 Control part 41 Outdoor heat exchanger temperature sensor

  The present invention relates to a heat pump system including an outdoor heat exchanger that serves as an evaporator during heating operation.

In an air conditioner (heat pump system), a phenomenon (frosting phenomenon) occurs in which moisture in the air becomes frost and adheres to an outdoor heat exchanger serving as an evaporator during heating operation. And if the amount of frost formation which adheres to an outdoor heat exchanger increases during heating operation, the ventilation resistance of an outdoor heat exchanger will increase and it will become difficult to maintain predetermined heating capacity. Therefore, when the amount of frost formation in the outdoor heat exchanger increases to a predetermined amount, a defrosting operation for removing frost attached to the outdoor heat exchanger is performed. Here, it is desirable that the defrosting operation is continued until the frost adhered to the outdoor heat exchanger is completely removed, but it may take a very long time under a condition where the outside air temperature is low. In such a case, in order to prevent the defrosting operation from continuing for a long time and not easily switching to the heating operation, in the air conditioner, the defrosting operation removes the frost attached to the outdoor heat exchanger to some extent. It is common to end the operation for a predetermined time and forcibly switch to the heating operation (see, for example, Patent Document 1).
JP-A-11-83117

  However, when the defrosting operation is forcibly switched to the heating operation, the frost attached to the outdoor heat exchanger is not completely removed, and residual frost is generated in the outdoor heat exchanger. Therefore, the heating operation after the defrosting operation is started in a state where residual frost is generated in the outdoor heat exchanger. Therefore, if heating operation is continued as it is, frost adheres to the outdoor heat exchanger, so that the frost attached to the outdoor heat exchanger cannot be completely removed in the normal defrosting operation. As a result, the heating operation capacity is significantly reduced, and in some cases, frost adhering to the outdoor heat exchanger freezes, and the outdoor heat exchanger cannot be used at all, or gas leakage due to pipe rupture occurs. There is.

  Then, the main objective of this invention is to provide the heat pump system which can eliminate the problem resulting from the residual frost in an outdoor heat exchanger.

A heat pump system according to a first aspect of the present invention is a heat pump system including an indoor heat exchanger, an outdoor heat exchanger, a compressor, and a pressure reducing mechanism, and a predetermined lower limit time has elapsed since the start of heating operation. In addition, when the temperature detected by the temperature sensor disposed in the outdoor heat exchanger during the heating operation becomes equal to or lower than the defrosting operation start temperature, the defrosting operation is switched, and during the defrosting operation, the temperature sensor When the detected temperature is equal to or higher than the defrosting operation release temperature or when the defrosting operation is continued for a predetermined upper limit time, the operation is switched to the heating operation, and the defrosting operation is continued for the predetermined upper limit time. heating operation is when switched, and, when defrost of the outdoor heat exchanger (2) when the defrosting operation is continued for the predetermined upper limit time is not a predetermined defrost condition, Is characterized in that serial predetermined lower limit time is shortened.
Here, the “predetermined defrosting state” indicates a state in which the defrosting in the outdoor heat exchanger is not completely completed but the defrosting in the outdoor heat exchanger is almost completed. Therefore, when the defrosting state in the outdoor heat exchanger is the predetermined defrosting state, it is considered that the residual frost in the outdoor heat exchanger hardly affects the heating operation.

In this heat pump system, when the defrosting operation is continued for a predetermined upper limit time and switched to the heating operation, it is determined that the defrosting in the outdoor heat exchanger is not completely completed (or insufficient). In the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened. Therefore, in the heating operation after the defrosting operation, the operation is easily switched to the defrosting operation, and the operation is switched to the defrosting operation with a relatively small amount of frost formation in the outdoor heat exchanger. Therefore, it is possible to prevent the heating operation capacity from being significantly reduced, and the frost attached to the outdoor heat exchanger is frozen, so that the outdoor heat exchanger cannot be used at all or gas leakage due to pipe rupture occurs. Can be prevented.
In addition, even when the defrosting operation is continued for the predetermined upper limit time and switched to the heating operation, if it can be determined that the defrosting in the outdoor heat exchanger is almost completed, the heating operation after the defrosting operation is in progress. In this case, the predetermined lower limit time until the switching to the defrosting operation becomes possible is not shortened. Therefore, since it becomes easy to switch to the defrosting operation in the heating operation after the defrosting operation, it is possible to suppress the time during which the heating operation is continued from being shortened.

The heat pump system according to the second invention is the heat pump system according to the first invention, wherein the defrosting operation is switched to the heating operation by continuing for the predetermined upper limit time , and the defrosting operation. When the defrosting state in the outdoor heat exchanger (2) when it continues for the predetermined upper limit time is not the predetermined defrosting state, the predetermined lower limit time is shortened to zero.

  In this heat pump system, during the heating operation after the defrosting operation, since the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is reduced to 0, regardless of the duration of the heating operation, The heating operation is switched to the defrosting operation only when the temperature detected by the temperature sensor arranged in the outdoor heat exchanger is equal to or lower than the defrosting operation start temperature. Therefore, in the heating operation after the defrosting operation, it becomes easier to switch to the defrosting operation, and the operation is switched to the defrosting operation with a small amount of frost on the outdoor heat exchanger.

A heat pump system according to a third aspect of the present invention is the heat pump system according to the first or second aspect of the present invention, wherein the predetermined defrosting state is a target in which the temperature detected by the temperature sensor is lower than the defrosting operation release temperature. It is the state which becomes more than heat exchange temperature.

  In this heat pump system, the state where the defrosting in the outdoor heat exchanger is almost completed can be easily determined based on the temperature detected by the temperature sensor arranged in the outdoor heat exchanger.

A heat pump system according to a fourth invention is the heat pump system according to any one of the first to third inventions, wherein the heat pump system does not switch to the defrosting operation until a predetermined minimum time has elapsed from the start of the heating operation. It is said.

  In this heat pump system, since it does not switch to the defrosting operation until the predetermined minimum time has elapsed since the start of the heating operation, the time for which the heating operation is continued by switching to the defrosting operation in a short time after starting the heating operation. Can be suppressed.

A heat pump system according to a fifth invention is the heat pump system according to any one of the first to fourth inventions, wherein the defrosting operation start temperature until a predetermined time elapses from the start of the heating operation is the predetermined time. Is set to be lower than the defrosting operation start temperature after elapse of time.

  In this heat pump system, since it becomes difficult to switch to the defrosting operation until a predetermined time has elapsed from the start of the heating operation, the time for which the heating operation is continued by switching to the defrosting operation in a short time after the heating operation starts. Can be suppressed.

  As described above, according to the present invention, the following effects can be obtained.

In the first invention, when the defrosting operation is switched to the heating operation by continuing for the predetermined upper limit time, the defrosting in the outdoor heat exchanger is not completely completed (or insufficient). In the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened. Therefore, in the heating operation after the defrosting operation, the operation is easily switched to the defrosting operation, and the operation is switched to the defrosting operation with a relatively small amount of frost formation in the outdoor heat exchanger. Therefore, it is possible to prevent the heating operation capacity from being significantly reduced, and the frost attached to the outdoor heat exchanger is frozen, so that the outdoor heat exchanger cannot be used at all or gas leakage due to pipe rupture occurs. Can be prevented.
In addition, even when the defrosting operation is continued for the predetermined upper limit time and switched to the heating operation, if it can be determined that the defrosting in the outdoor heat exchanger is almost completed, the heating operation after the defrosting operation is in progress. In this case, the predetermined lower limit time until the switching to the defrosting operation becomes possible is not shortened. Therefore, since it becomes easy to switch to the defrosting operation in the heating operation after the defrosting operation, it is possible to suppress the time during which the heating operation is continued from being shortened.

  In the second invention, during the heating operation after the defrosting operation, the predetermined lower limit time until it becomes possible to switch to the defrosting operation again is shortened to 0, regardless of the duration of the heating operation. The heating operation is switched to the defrosting operation only when the temperature detected by the temperature sensor arranged in the outdoor heat exchanger is equal to or lower than the defrosting operation start temperature. Therefore, in the heating operation after the defrosting operation, it becomes easier to switch to the defrosting operation, and the operation is switched to the defrosting operation with a small amount of frost formation on the outdoor heat exchanger.

In the third aspect, the state in which the defrosting in the outdoor heat exchanger is almost completed can be easily determined based on the temperature detected by the temperature sensor arranged in the outdoor heat exchanger.

In 4th invention, since it does not switch to defrost operation until predetermined minimum time passes from the time of heating operation start, heating operation is continued by switching to defrost operation for a short time after heating operation start. It is possible to suppress the time from being shortened.

In 5th invention, since it becomes difficult to switch to defrosting operation until predetermined time passes since heating operation start, heating operation is continued by switching to defrosting operation for a short time after heating operation start. It is possible to suppress the time from being shortened.

  Hereinafter, embodiments of an air conditioner (heat pump system) according to the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of an air conditioner according to an embodiment of the present invention.

  In the refrigerant circuit diagram of the air conditioner 10 of FIG. 1, the primary port of the four-way switching valve 5 is connected between the discharge side and the suction side of the compressor 3 that is controlled to be variable in compression capacity by an inverter. . And between the secondary ports of the four-way switching valve 5, the first gas pipe 6, the outdoor heat exchanger 2, the first liquid pipe 7, the electric expansion valve 4, the second liquid pipe 8, the indoor heat exchanger 1, The second gas pipe 9 is connected in order.

  Here, by switching the four-way switching valve 5 in the direction of the solid line, the cooling operation can be performed by causing the outdoor heat exchanger 2 to function as a condenser and the indoor heat exchanger 1 to function as an evaporator. On the other hand, by switching the four-way switching valve 5 in the direction of the broken line, the outdoor heat exchanger 2 can function as an evaporator and the indoor heat exchanger 1 can function as a condenser. In the air conditioner 10, the four-way switching valve 5 can be switched from the heating operation to the defrosting operation by switching the four-way switching valve 5 from the broken line direction to the solid line direction during the heating operation. Can be switched from the defrosting operation to the heating operation by switching from the solid line direction to the broken line direction.

  Next, the configuration of the control unit of the air conditioner 10 of the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing a configuration of a control unit of the air conditioner of FIG.

  The control unit 30 includes an operation setting storage unit 31, a heating operation timer 32, a defrosting operation timer 33, and a control unit 34. The control unit 30 is connected to an outdoor heat exchanger temperature sensor 41 disposed in the outdoor heat exchanger 2 and the four-way switching valve 5. In the present embodiment, the outdoor heat exchange temperature sensor 41 is arranged at an intermediate position of the outdoor heat exchanger 2, but the arrangement can be changed.

  The operation setting storage unit 31 stores various operation settings related to the air conditioner 10. The operation setting stored in the operation setting storage unit 31 includes the minimum guard time (for example, 6 minutes) that is the minimum duration of the heating operation and until it becomes possible to switch to the defrosting operation during the normal heating operation. Heating operation guard time (for example, 30 minutes), defrosting operation guard time (for example, 10 minutes) until the defrosting operation is forcibly switched to heating operation, and heating operation to defrosting operation When defrosting operation start temperature (for example, temperature represented by a relational expression including variables relating to the outside air temperature and the operating frequency of the compressor), which is the outdoor heat exchange temperature when switching to, and when switching from defrosting operation to heating operation The defrosting operation cancellation temperature (for example, the temperature represented by a relational expression including a variable related to the outside air temperature) that is the temperature of the outdoor heat exchanger and the target that is the outdoor heat exchange temperature when the defrosting in the outdoor heat exchanger 2 is almost completed Exchanger temperature (e.g. than the defrosting operation canceling temperature 2 to 3 ° C. lower temperature) are included and are.

  The heating operation timer 32 measures the time during which the heating operation is performed, and is returned to 0 each time the heating operation is completed (every time the operation is switched to the defrosting operation or the cooling operation). The defrosting operation timer 33 measures the time during which the defrosting operation is performed, and is reset to 0 each time the defrosting operation is completed (every time the operation is switched to the heating operation).

  The control unit 34 controls the operating state of the air conditioner 10 by switching the refrigerant path of the four-way switching valve 5. Specifically, the control unit 34 switches the operation state of the air conditioner 10 from, for example, the heating operation to the defrosting operation and the switching from the defrosting operation to the heating operation.

  In the normal heating operation, the control unit 34 performs the defrosting operation when the outdoor heat exchange temperature becomes equal to or lower than the defrosting operation start temperature after the heating operation guard time has elapsed from the start of the heating operation. Switch to. Here, the normal heating operation refers to a heating operation after the start of the heating operation and before switching to the defrosting operation, and heating when the outdoor heat exchange temperature becomes equal to or higher than the defrosting operation release temperature during the defrosting operation. Heating operation after defrosting operation when switched to operation, and defrosting operation continues for defrosting operation guard time, switching to heating operation, and outdoor heat exchange temperature when defrosting operation guard time elapses is the target The heating operation after the defrosting operation when the temperature is equal to or higher than the heat exchange temperature is shown.

  Further, the control unit 34 defrosts when the defrosting operation is switched to the heating operation by continuing the defrosting operation guard time and the outdoor heat exchange temperature when the defrosting operation guard time elapses is not equal to or higher than the target heat exchange temperature. When the outdoor heat exchange temperature becomes equal to or lower than the defrosting operation start temperature during the heating operation after the operation, the heating operation is switched to the defrosting operation.

  Further, the control unit 34 changes from the defrosting operation to the heating operation when the outdoor heat exchange temperature becomes equal to or higher than the defrosting operation release temperature during the defrosting operation and when the defrosting operation is continued for the defrosting operation guard time. Switch.

  In the present embodiment, the control unit 34 does not switch from the heating operation to the defrosting operation until the minimum guard time has elapsed from the start of the heating operation.

  Next, the operation | movement procedure at the time of the heating operation of the air conditioner 10 of this Embodiment is demonstrated with reference to FIG. FIG. 3 is a flowchart showing an operation procedure during the heating operation of the air conditioner of the present embodiment.

  First, when the operation for starting the heating operation is performed by the user, the heating operation is started, and at the same time, measurement by the heating operation timer 32 is started (step S1). Then, it is repeatedly determined whether or not the minimum guard time has elapsed since the start of the heating operation (whether or not the measurement time in the heating operation timer 32 has passed the minimum guard time) (step S2). Here, when the minimum guard time has elapsed since the start of the heating operation (S2: YES), whether the heating operation guard time has elapsed since the start of the heating operation (the time measured by the heating operation timer 32 is the heating time). Whether or not the driving guard time has passed is repeatedly determined (step S3).

  When the heating operation guard time has elapsed since the start of the heating operation (S3: YES), the outdoor heat exchange temperature detected by the outdoor heat exchange temperature sensor 41 is equal to or lower than the defrosting operation start temperature during the heating operation. Is repeatedly determined (step S4). Here, when the outdoor heat exchange temperature is equal to or lower than the defrosting operation start temperature (S4: YES), the measurement by the defrosting operation timer 33 is started simultaneously with switching from the heating operation to the defrosting operation (step) S5). Then, during the defrosting operation, it is repeatedly determined whether or not the outdoor heat exchange temperature is equal to or higher than the defrosting operation release temperature (step S6). When the outdoor heat exchange temperature is equal to or higher than the defrosting operation release temperature (S6: YES), the defrosting operation is switched to the heating operation, and then the process returns to step S2 and the same processing as described above is repeated. That is, in the heating operation after the defrosting operation in this case, it is possible to switch to the defrosting operation after the heating operation guard time has elapsed from the start of the heating operation, and the heating operation guard time from the start of the heating operation. It will not be switched to the defrosting operation until has passed.

  In step S6, if the outdoor heat exchange temperature is not equal to or higher than the defrosting operation release temperature (S6: NO), whether or not the defrosting operation guard time has elapsed since the start of the defrosting operation (in the defrosting operation timer 33). Whether or not the measurement time of the defrosting operation guard time has elapsed is repeatedly determined (step S8). If the defrosting operation guard time has elapsed since the start of the defrosting operation (S8: YES), it is repeatedly determined whether or not the outdoor heat exchange temperature is equal to or higher than the target heat exchange temperature during the defrosting operation. (Step S9).

  Here, when the outdoor heat exchange temperature is equal to or higher than the target heat exchange temperature (S9: YES), the process proceeds to step S7, the defrosting operation is switched to the heating operation, and then the process returns to step S2 and is the same as described above. The process is repeated. That is, in the heating operation after the defrosting operation in this case, it is possible to switch to the defrosting operation after the heating operation guard time has elapsed from the start of the heating operation, and the heating operation guard time from the start of the heating operation. It will not be switched to the defrosting operation until has passed.

  On the other hand, when the outdoor heat exchange temperature is not equal to or higher than the target heat exchange temperature (S9: NO), the process proceeds to step S10, and the defrosting operation is switched to the heating operation. Thereafter, whether or not the minimum guard time has elapsed since the start of the heating operation after the defrosting operation (whether or not the measurement time in the heating operation timer 32 has passed the minimum guard time) is repeatedly determined (step S11). . Here, when the minimum guard time has elapsed from the start of the heating operation after the defrosting operation (S11: YES), the process returns to step S4 and the same processing as described above is repeated. That is, in the heating operation after the defrosting operation in this case, if the heating operation time has passed the minimum guard time, the heating operation is switched to the defrosting operation even after the heating operation guard time has elapsed from the start of the heating operation. It is possible to change.

  In step S8, when the defrosting operation guard time has not elapsed since the start of the defrosting operation (S8: NO), the process returns to step S6 and the same processing as described above is repeated.

  As described above, in the air conditioner 10 of the present embodiment, the defrosting operation is switched to the heating operation by continuing the defrosting operation guard time, and the outdoor heat exchange temperature when the defrosting operation guard time elapses is set. In the heating operation after the defrosting operation when the temperature is not equal to or higher than the target heat exchange temperature, the defrosting in the outdoor heat exchanger 2 in the defrosting operation is not completely completed (or insufficient), so the heating operation guard time Is reduced to zero. Therefore, in the heating operation after the defrosting operation, even if it is before the heating operation guard time elapses from the start of the heating operation, the outdoor heat exchange temperature is switched to the defrosting operation only at or below the defrosting operation start temperature. Since it becomes possible and it becomes easy to switch to a defrosting operation, it switches to a defrosting operation in the state where there is little frost formation amount to an outdoor heat exchanger. Therefore, it is possible to prevent the heating operation capacity from being significantly reduced, and the frost attached to the outdoor heat exchanger is frozen, so that the outdoor heat exchanger cannot be used at all or gas leakage due to pipe rupture occurs. Can be prevented.

  Even if the defrosting operation is switched to the heating operation by continuing the defrosting operation guard time, if the outdoor heat exchange temperature after the defrosting operation guard time has exceeded the target heat exchange temperature, the outdoor It is determined that the defrosting in the heat exchanger is almost completed, and the heating operation guard time is not shortened. Therefore, since it becomes easy to switch to the defrosting operation in the heating operation after the defrosting operation, it is possible to suppress the time during which the heating operation is continued from being shortened.

  In addition, since the defrosting operation is not switched until the minimum guard time has elapsed since the start of the heating operation, the time for which the heating operation is continued is shortened by switching to the defrosting operation in a short time after the heating operation is started. Can be suppressed.

  As mentioned above, although embodiment of this invention was described based on drawing, specific structure is not restricted to these embodiment, It can change in the range which does not deviate from the summary of invention.

In the above-described embodiment, the defrosting operation is switched to the heating operation by continuing the defrosting operation for the defrosting operation guard time, and the outdoor heat exchange temperature when the defrosting operation guard time elapses is not equal to or higher than the target heat exchange temperature. In the heating operation after the operation, the heating operation guard time is shortened to 0, but the heating operation guard time may be shortened from the original time to a time other than 0 .

  In the above-described embodiment, after the minimum guard time has elapsed from the start of the heating operation, it is possible to switch from the heating operation to the defrosting operation, but a predetermined time has elapsed from the start of the heating operation. The defrosting operation start temperature until may be set lower than the subsequent defrosting operation start temperature. In this case, since it becomes difficult to switch to the defrosting operation until a predetermined time has elapsed from the start of the heating operation, the time for which the heating operation is continued by switching to the defrosting operation in a short time after the heating operation starts. Shortening can be suppressed.

  In the above-described embodiment, it is determined that the defrosting in the outdoor heat exchanger is almost completed when the outdoor heat exchange temperature when the defrosting operation guard time elapses is equal to or higher than the target heat exchange temperature. By this method, it may be determined that the defrosting in the outdoor heat exchanger is almost completed.

  By using the present invention, it is possible to suppress a significant decrease in heating operation capacity, and the frost adhering to the outdoor heat exchanger freezes, so that the outdoor heat exchanger cannot be used at all, or a gas leak due to a pipe rupture. Can be prevented.

It is a refrigerant circuit figure of the air conditioner concerning an embodiment of the invention. It is a block diagram which shows the structure of the control unit of the air conditioner of FIG. It is a flowchart which shows the operation | movement procedure at the time of the heating operation of the air conditioner of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Indoor heat exchanger 2 Outdoor heat exchanger 3 Compressor 4 Electric expansion valve 10 Air conditioner 30 Control unit 31 Operation setting memory | storage part 32 Heating operation timer 33 Defrosting operation timer 34 Control part 41 Outdoor heat exchanger temperature sensor

Claims (6)

An air conditioner (10) comprising an indoor heat exchanger (1), an outdoor heat exchanger (2), a compressor (3), and a pressure reducing mechanism (4),
When the predetermined lower limit time has elapsed from the start of the heating operation and the temperature detected by the temperature sensor (41) disposed in the outdoor heat exchanger (2) during the heating operation is equal to or lower than the defrosting operation start temperature. When switching to the defrosting operation and the temperature detected by the temperature sensor (41) is equal to or higher than the defrosting operation release temperature during the defrosting operation or when the defrosting operation is continued for a predetermined upper limit time, the heating operation is performed. Is switched to
The air conditioner (10), wherein the predetermined lower limit time is shortened when the defrosting operation is continued for the predetermined upper limit time to switch to the heating operation.   The air conditioner (10) according to claim 1, wherein the predetermined lower limit time is shortened to 0 when the defrosting operation is continued for the predetermined upper limit time to switch to the heating operation.   The predetermined lower limit time is not shortened when the defrosting state in the outdoor heat exchanger (2) when the defrosting operation is continued for the predetermined upper limit time is a predetermined defrosting state. The air conditioner (10) according to 1 or 2.   The air according to claim 3, wherein the predetermined defrosting state is a state in which a temperature detected by the temperature sensor (41) is equal to or higher than a target heat exchange temperature lower than the defrosting operation release temperature. Harmonic machine (10).   The air conditioner (10) according to any one of claims 1 to 4, wherein the air conditioner (10) is not switched to a defrosting operation until a predetermined minimum time has elapsed from the start of the heating operation.   The defrosting operation start temperature from when the heating operation starts until a predetermined time elapses is set lower than the defrosting operation start temperature after the predetermined time elapses. The air conditioner (10) according to any one of the above.

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