JP4451680B2 - Air conditioner - Google Patents

Description

  The present invention is a split type air conditioner in which an outdoor unit and an indoor unit that use a non-chlorine refrigerant that does not destroy the ozone layer as a working refrigerant are separated from the refrigerant HCFC22 used as a working fluid. Furthermore, the present invention relates to a replacement use in which a connection pipe between an outdoor unit and an indoor unit that uses HCFC 22 as a refrigerant is used.

  Air conditioners that use non-chlorine refrigerants such as HFC410A that have been subject to production restrictions and have not been destroyed by the ozone layer, because refrigerants such as HCFC22 that have been generally used in air conditioners in recent years due to global environmental problems such as ozone layer protection The conversion to is done.

  In Japan, air conditioners are mainly split type, with indoor and outdoor units separated, and there are connecting pipes connecting the indoor and outdoor units. In commercial air conditioners, etc., the distance between the outdoor unit and the indoor unit is long, and connection pipes embedded in the ceiling, pipe shaft, etc. are often used. In many cases, pipes are reused as they are.

  However, HFC410A, which is the main alternative refrigerant of HCFC22 refrigerant, has a pressure at the same condensation temperature of about 1.6 times that of HCFC, so let's divert the connection piping used in the conventional air conditioner using HCFC22. Then, a case where the pressure resistance of the connection pipe does not occur occurs.

When using HFC410A, which is a low-boiling point refrigerant, a pressure sensing device is installed so that the connection piping used in the conventional refrigerant HCFC22 etc. can be diverted without any pressure problems, and the pressure limit is reached when the set pressure is reached. There are some which use the means to operate the discharge pressure below an arbitrary limit pressure (for example, see Patent Document 1).
JP 2003-2044 A JP 2002-162126 A

  However, in the thing of the said patent document 1, since the delay to the refrigerating cycle system by the actuator control after pressure sensing, etc. are not considered, there exists a possibility of exceeding the pressure which connection piping accept | permits.

  In addition, if the sensing pressure of the pressure sensing device is reduced in consideration of overshoot, the range of use of the condensation temperature is narrowed, causing an extreme decline in capacity during operation such as cooling overload conditions. Therefore, when diverting the low allowable pressure connection pipe used in HCFC22, it is necessary to control the pressure to be controlled as close as possible to the pressure allowed by the connection pipe and not to exceed the allowable pressure. There is.

  As a specific problem, since outdoor units are generally installed outdoors that are affected by outside winds, for example, during cooling operation, they are affected by outside winds that are stronger than the blowing direction of the outdoor blower. In such a case, the air flow rate of the blower decreases, the condensation capacity of the outdoor heat exchange air decreases, the pressure increases rapidly, and even if pressure limiting means is applied, there may be frequent cases of operation exceeding the allowable pressure. . In the case of an air conditioner having a pressure circuit breaker, the pressure circuit breaker may operate and become inoperable.

  The present invention was made to solve the above-described problems, and in an unstable environment such as an outdoor wind where an outdoor unit is placed, the operating pressure is suppressed as much as possible in a strong wind, and an abnormal increase in discharge pressure is caused. Capability to avoid problems such as compressor shutdown due to pressure circuit breaker operation and to expand the pressure range that can be operated as much as possible in a state where relatively stable operation such as no wind or light wind is possible. An object of the present invention is to provide an air conditioner capable of ensuring the above.

  An air conditioner according to the present invention includes a compressor, a four-way valve, an outdoor heat exchanger, an electronic expansion valve, a pressure breaker connected to the discharge side of the compressor, an outdoor unit having an outdoor blower, an indoor heat exchanger, An indoor unit having an indoor blower, an existing connection pipe that connects the outdoor unit and the indoor unit, a compressor of the outdoor unit, a four-way valve, an outdoor heat exchanger, an electronic expansion valve, an indoor heat exchanger of the indoor unit, connection A refrigeration cycle having a piping and using a non-chlorine refrigerant as a refrigerant and a low-boiling point refrigerant, and a high-pressure side pressure detecting means for detecting a high-pressure side pressure during cooling operation of the refrigeration cycle. The high pressure side that is set lower than the allowable pressure of the existing connection piping and the high pressure side pressure detected by the high pressure side pressure detection means is set to be lower than the cutoff pressure of the pressure circuit breaker. If the pressure becomes higher than the pressure, the compressor or the outdoor fan Alternatively, control the electronic expansion valve to lower the high-pressure side pressure until it reaches the target value, and if the limited high-pressure side pressure is not exceeded for a certain period of time, the high-pressure side pressure is adjusted within the range that does not exceed the cutoff pressure of the pressure circuit breaker. It is controlled to raise.

  The air conditioner according to the present invention suppresses the operating pressure as much as possible in an unstable environment such as an outside wind where the outdoor unit is placed, and avoids problems such as an abnormal increase in discharge pressure and a compressor stop due to pressure interruption. In addition, in a state where a relatively stable operation can be performed such as a windless state or a light wind state, it is possible to secure the capability by operating with a pressure range that can be operated as much as possible.

Embodiment 1 FIG.
1 to 9 are diagrams showing Embodiment 1, FIG. 1 is a simplified diagram showing a configuration of an air conditioner to be controlled, and FIG. 2 is a perspective view showing a state in which an indoor unit and an outdoor unit are connected by a connection pipe. 3 is a diagram showing a refrigerant circuit and a control circuit of an air conditioner, FIG. 4 is a conceptual diagram of a control unit, FIG. 5 is a block diagram showing an inverter driving device, FIG. 6 is a diagram showing characteristics of an alternative refrigerant, FIG. FIG. 8 is a view showing a state where a back wind blows to the outdoor unit, FIG. 8 is a view showing a pressure (condensation temperature) in the cooling operation, and FIG. 9 is a flowchart showing the operation.

  In the present embodiment, in an unstable environment such as an outdoor wind where the outdoor unit is placed, the operating pressure is suppressed as much as possible in the case of strong winds, and problems such as abnormal rise in discharge pressure and compressor shutdown due to pressure interruption are avoided. Or, in a state where a relatively stable operation such as a light wind can be performed, an example will be described in which the ability can be ensured by operating with a pressure range that can be operated as wide as possible.

  As shown in FIG. 1, an indoor unit 20 and an outdoor unit 30 of an air conditioner that uses an HFC refrigerant that is an alternative refrigerant are connected by diverting existing connection pipes 5 and 7 that have been used for an HCFC 22 refrigerant. Often.

  As shown in FIG. 2, in a commercial air conditioner or the like, the distance between the outdoor unit 30 and the indoor unit 20 is long, and connection pipes 5 and 7 embedded in the ceiling, pipe shaft, etc. are often used. When the indoor unit and / or the outdoor unit is replaced, the connection pipes 5 and 7 are often reused as they are.

  Part of the refrigerant circuit and the control circuit of the air conditioner is configured as shown in FIG. The refrigerant circuit of the outdoor unit 30 compresses the refrigerant and discharges the high-temperature and high-pressure gas refrigerant, the four-way valve 2 that switches the refrigerant flow direction between the cooling operation and the heating operation, and performs heat exchange with the outdoor air. Outdoor heat exchanger 3, electronic expansion valve 4 that decompresses and expands the high-pressure liquid refrigerant into a two-phase refrigerant, accumulator 8 that stores the liquid refrigerant so that the liquid refrigerant does not return to the compressor 1, and detects the pressure for electricity It is composed of refrigerant circuit components of the pressure circuit breaker 11 that shuts down the circuit and stops the operation of the air conditioner. In addition, the temperature of the outdoor fan 10 that blows air to the outdoor heat exchanger 3 and the temperature of the outdoor heat exchanger 3 are detected. An outdoor heat exchanger temperature detecting means 12 (an example of a high pressure side pressure detecting means) is provided.

  A part of the control circuit of the outdoor unit 30 controls the outdoor blower 10 via the phase control unit 16 by the output of the outdoor heat exchanger temperature detection means 12 and also controls the compressor 1 via the inverter circuit 15. The control part 14 comprised with a computer is provided.

  As shown in the conceptual diagram of FIG. 4, the control unit 14 is phased by the output of a compressor control unit (inverter circuit control unit) that controls the compressor 1 via an inverter circuit, for example, the outdoor heat exchanger temperature detection means 12. A fan control unit that controls the outdoor blower 10 via the control unit 16, an electronic expansion valve control unit that controls the opening degree of the electronic expansion valve 4 when controlling the pressure of the refrigerant circuit, and a cooling operation and a heating operation It has a four-way valve control unit for controlling the four-way valve 2 for switching the flow direction, a protection control unit for protecting the compressor 1 and the like.

  As shown in FIG. 5, the converter circuit 18 connected to the power source 21 is controlled by a converter control unit 19 based on a DC voltage command. While the DC voltage that is the output of the converter circuit 18 is controlled by the inverter circuit 15 based on the rotor position information and AC output voltage information of the motor of the compressor 1 of the control unit 14, It is converted into a sine wave AC voltage to drive the motor of the compressor 1.

  The indoor unit 20 includes an indoor heat exchanger 6 that exchanges heat with indoor air, an indoor fan 9 that blows air to the indoor heat exchanger 6, and an indoor heat exchanger temperature detection unit 13 that detects the temperature of the indoor heat exchanger 6. And is connected to the outdoor unit 30 by connection pipes 5 and 7 to constitute a refrigerant circuit.

  The refrigerant flow during the cooling operation is as follows: compressor 1, four-way valve 2, outdoor heat exchanger 3, electronic expansion valve 4, connection pipe 5, indoor heat exchanger 6, connection pipe 7, four-way valve 2, accumulator 8, compression It becomes machine 1 order. Since the connecting pipes 5 and 7 are on the low-pressure side, there is no problem with pressure resistance even if existing pipes are used.

  The refrigerant flow during the heating operation is as follows: compressor 1, four-way valve 2, connection pipe 7, indoor heat exchanger 6, connection pipe 5, electronic expansion valve 4, outdoor heat exchanger 3, four-way valve 2, accumulator 8, compression It becomes machine 1 order. The connection pipes 5 and 7 are on the high pressure side, and when using existing pipes, a problem of pressure resistance occurs. Therefore, as shown in FIG. 3, a pressure circuit breaker 11 is provided to stop the operation when a discharge pressure is detected on the discharge side of the compressor 1 and a cut-off pressure equal to or lower than an allowable pressure of the existing piping is detected.

  The design pressure when the HCFC22 refrigerant is used for air conditioning is usually designed around 2.8 MPa (condensation temperature of about 65 ° C.), and generally 0.8 mm and φ19 for piping up to φ15.88 mm. If it is 0.05 to 22.2 mm, a pipe thickness of 1.0 mm is used. If the pipe thickness of the refrigerant pipe is the same, the greater the pipe diameter, the lower the pressure resistance. The pressure resistance of piping up to φ15.88 mm (pipe thickness 0.8 mm) varies depending on the pipe diameter, but the pressure resistance of piping (pipe thickness 1.0 mm) of 4.2 MPa or more and φ19.05 to 22.2 mm is as follows: It is around 3.6 MPa.

The working fluid used in the present embodiment is, for example, HFC410A often used as an alternative refrigerant for HCFC22.
The refrigerant characteristics of the alternative refrigerant are shown in FIG. As shown in the figure, HFC410A has a pressure at the same condensation temperature about 1.6 times that of HCFC22. The HFC410A refrigerant has a lower boiling point than the HCFC22 refrigerant, and the pressure is about 4.17 MPa at the same condensation temperature of 65 ° C. as that of the HCFC22 refrigerant. , Φ19.05 to 22.2 mm pipe (pipe wall thickness 1.0 mm) is around 3.6 MPa, so that a connection pipe that cannot maintain sufficient strength in terms of pressure is generated.

  In order to divert the connection pipes that have been used in the past, it is necessary to reduce the pressure to a level where there is no problem in terms of pressure by increasing the heat exchanger capacity of the condenser and to operate at a low condensation temperature. appear. In such a situation, it would be desirable to operate to the limit of allowable pressure.

  If the pressure circuit breaker 11 is used to protect the existing connection piping during the heating operation, if for some reason the discharge pressure of the compressor 1 rises rapidly, the pressure circuit breaker 11 is activated and the operation is stopped. For example, as shown in FIG. 7, when the back wind blows to the outdoor unit 30 during the cooling operation, the rotational speed of the outdoor blower 10 is drastically reduced, and the pressure of the outdoor heat exchanger 3 serving as a condenser is reduced. To rise. When the pressure exceeds the breaking pressure of the pressure breaker 11, the pressure breaker 11 is activated and the operation is stopped. Since the cutoff pressure is set according to the pressure resistance of the existing connection pipe, the existing connection pipe is low pressure during cooling operation. I want to continue driving.

  Therefore, in order to suppress the operation of the pressure circuit breaker 11 during the cooling operation as much as possible, the discharge pressure of the compressor 1 is lowered so that the pressure circuit breaker 11 does not operate even under adverse conditions in which the back wind blows to the outdoor unit 30. An example of performing control so that the vehicle is operated will be described below.

  FIG. 8 shows the pressure in the cooling operation (synonymous with the condensation temperature). The capacity of the compressor 1 is controlled with the normal operation condensing temperature (pressure) as a target. The condensation temperature is detected from the outdoor heat exchanger temperature detection means 12, but a pressure sensor (another example of the high pressure side pressure detection means) may be used.

In the normal cooling operation, the condenser that affects the discharge pressure becomes the outdoor heat exchanger 3, and, for example, when a back wind blows to the outdoor fan 10, a condensation failure occurs and the pressure temporarily rises, and the limited condensation temperature B ( Lower than the cutoff pressure of the pressure circuit breaker 11). In this case, it is determined that there is a possibility that the pressure may exceed the shut-off pressure due to the back wind, and the capacity control of the compressor 1 or the rotational speed control of the outdoor blower 10 or the electronic expansion valve is performed so that the operation pressure becomes the operation condensation temperature B. Operation is performed with the opening degree control of 4.
The restricted high pressure side pressure corresponds to the restricted condensation temperature.

  When the stronger back wind exceeds the blowing restricted condensation temperature A (lower than the breaking pressure of the pressure circuit breaker 11 but higher than the restricted condensation temperature B), the operation pressure is further lowered to operate at the operation condensation temperature A. If the pressure limit is no longer exceeded for a certain period of time, increase the operation condensing temperature from A to B to normal, and operate at a discharge pressure as high as possible so long as the pressure does not exceed the shut-off pressure of the pressure breaker 11 Can be performed.

  On the other hand, when there is no wind outside or when normal wind is blowing against the outdoor blower 10, the discharge pressure does not rise transiently, so that it is possible to operate at normal operating pressure.

The operation of the present embodiment will be summarized with the flowchart of FIG.
First, in step S1, the air conditioner is performing a cooling operation.
In step S2, the temperature of the outdoor heat exchanger 3 is stabilized and is operated at the normal operation condensing temperature.
In step S3, the temperature of the outdoor heat exchanger 3 is compared with the limited condensation temperature B.
When the temperature of the outdoor heat exchanger 3 becomes higher than the limited condensation temperature B due to the influence of the back wind or the like, the temperature of the outdoor heat exchanger 3 is compared with the limited condensation temperature A in step S4 (the limited condensation temperature A). > Limited condensation temperature B).

When the temperature of the outdoor heat exchanger 3 is lower than the limited condensation temperature A, in step S12, control is performed to increase the rotational speed of the outdoor fan 10, decrease the rotational speed of the compressor 1, or increase the opening of the electronic expansion valve 4.
In step S13, operation is performed at the operation condensing temperature B.
In step S14, the continuous operation time at the operation condensing temperature B is determined (compared with a predetermined time Δτb). When the continuous operation time at the operation condensing temperature B exceeds the predetermined time Δτb, the process returns to step S2 to operate at the normal operation condensing temperature. When the continuous operation time at the operation condensing temperature B does not exceed the predetermined time Δτb, the process returns to step S4.

In step S4, when the temperature of the outdoor heat exchanger 3 is higher than the limit condensation temperature A, in step S5, the rotational speed of the outdoor fan 10 is decreased, the rotational speed of the compressor 1 is decreased, or the opening degree of the electronic expansion valve 4 is increased. Take control.
In step S6, operation is performed at the operation condensing temperature A (operation condensing temperature A <operation condensing temperature B).

In step S7, it is determined whether or not the predetermined time Δτa has elapsed since the operation condensation temperature A was detected. If the predetermined time Δτa has not elapsed, the process returns to step S6. When the predetermined time Δτa has elapsed, in step S8, control is performed to reduce the rotational speed of the outdoor fan 10, increase the rotational speed of the compressor 1, or decrease the opening of the electronic expansion valve 4.
In step S9, operation is performed at the operation condensing temperature B (operation condensing temperature B> operation condensing temperature A).

  In step S10, the temperature of the outdoor heat exchanger 3 is compared with the limited condensation temperature A (limited condensation temperature A> limited condensation temperature B). When the temperature of the outdoor heat exchanger 3 is higher than the limit condensation temperature A, the operation returns to step S6 and operates at the operation condensation temperature A. When the temperature of the outdoor heat exchanger 3 is lower than the limit condensation temperature A, the continuous operation time at the operation condensation temperature B is determined in step S11 (compared with a predetermined time Δτb). When the continuous operation time at the operation condensing temperature B exceeds the predetermined time Δτb, the process returns to step S2 to operate at the normal operation condensing temperature. If the continuous operation time at the operation condensing temperature B does not exceed the predetermined time Δτb, the process returns to step S9.

  According to the above-described embodiment, in an unstable environment such as an outdoor wind where the outdoor unit 30 is placed, the use pressure is suppressed as much as possible in a strong wind, the discharge pressure is abnormally increased, and the compressor is stopped by the pressure breaker 11. In a state where a relatively stable operation such as no wind or light wind can be performed, the capability can be ensured by widening the operable pressure range as much as possible.

Embodiment 2. FIG.
FIG. 10 is a diagram illustrating the second embodiment, and is a diagram illustrating an example in which a plurality of outdoor units are installed close to each other.
As shown in the figure, when a plurality of outdoor units 30 are installed close to each other, high-temperature air exchanged with the outdoor heat exchanger 3 is blown out from the outdoor unit 30 during the cooling operation. When this hot blown air hits another nearby outdoor unit 30, the temperature of the outdoor unit 30 rises, the temperature of the outdoor heat exchanger 3 also rises, and the operating condensing temperature is raised.

  Therefore, also in this case, the pressure circuit breaker 11 is activated, and the operation of the compressor 1 may be stopped. As in the first embodiment, control for reducing the discharge pressure of the compressor 1 is effective.

Embodiment 3 FIG.
FIGS. 11 to 14 are diagrams showing Embodiment 3, FIG. 11 is a refrigerant circuit diagram of an air conditioner, FIG. 12 is a diagram showing a change in discharge pressure during cooling operation, and FIG. 13 is a flowchart of control during fan block. FIG. 14 is a flowchart of the control during headwind.

  The configuration of the refrigerant circuit is the same as that in FIG. 3 of the first embodiment. The point in which the control part 14 (microcomputer) of the control circuit is provided with a timer 17 is different from FIG. 3 of the first embodiment.

  The present embodiment does not control the pressure circuit breaker 11 not to operate during the cooling operation as in the first embodiment, but rather controls the pressure circuit breaker during the cooling operation in order to suppress a decrease in the operating capacity of the air conditioner. 11 is allowed to work. However, if the operation of the pressure circuit breaker 11 is an erroneous detection due to a back wind, and if the erroneous detection is repeated, the pressure breaker 11 is controlled not to operate even in the case of a reverse wind by reducing the operating pressure.

  For example, when the outdoor blower 10 is in a fan block state where the temperature of the motor rises and stops due to the operation of the pressure breaker 11 and the outdoor heat exchanger 3 suddenly rises in temperature, , Control that stops abnormally and does not return automatically.

  In FIG. 12, the upper part shows the change in the discharge pressure during the back wind in the cooling operation, and the lower part shows a case where the discharge pressure is abnormally increased by the fan block of the outdoor blower 10.

  First, a mechanism that causes an abnormal stop during the fan block of the outdoor blower 10 will be described. The control unit 14 (microcomputer) that detects pressure interruption is provided with a plurality of timers that detect a certain time Δτ. In the present embodiment, when the pressure circuit breaker 11 detects the breaking pressure three times during a certain time Δτ, it is abnormally stopped and is not automatically returned.

  When the outdoor blower 10 is stopped by the fan block during the cooling operation, the discharge pressure rapidly rises due to the condensation failure of the outdoor heat exchanger 3, reaches the cutoff pressure of the pressure breaker 11, and temporarily stops the compressor 1. . When the pressure rises to the pressure shut-off value once, the second operation tries to lower the operating pressure by increasing the rotational speed of the outdoor fan, decreasing the frequency of the compressor, or increasing the opening of the electronic expansion valve by an actuator command from the microcomputer. Since the outdoor blower 10 is stopped, the pressure rapidly rises due to the condensation failure as in the first time, reaches the cutoff pressure of the pressure circuit breaker 11, and stops. The same phenomenon occurs at the third start-up, reaching the shut-off pressure of the pressure circuit breaker 11, and the air conditioner stops abnormally.

The operation will be described with reference to the flowchart of FIG.
First, a cooling operation is performed in step S21. During the operation, when the outdoor fan 10 is stopped by the fan block (step S22), the discharge pressure of the compressor 1 is increased (step S23). When the discharge pressure rises and the pressure circuit breaker 11 detects the cutoff pressure (step S24), the compressor 1 is temporarily stopped (step S25), and an actuator command for lowering the operating pressure is issued from the control unit 14 (microcomputer). A second operation is performed (step S26).

  However, since the outdoor blower 10 is stopped by the fan block, the discharge pressure of the compressor 1 increases (step S27). When the discharge pressure rises and the pressure circuit breaker 11 detects the shut-off pressure again (step S28), the compressor 1 is temporarily stopped (step S29), and an actuator command for lowering the operating pressure is issued from the control unit 14 (microcomputer). The third operation is performed (step S30). However, since the outdoor blower 10 is stopped by the fan block, when the discharge pressure of the compressor 1 rises and the pressure breaker 11 detects the breaking pressure again (step S31), the air conditioner is abnormally stopped. It is assumed that automatic restoration is not performed (step S32).

  As described above, when the outdoor blower 10 is stopped by the fan block, when the pressure breaker 11 detects the cutoff pressure three times, the fan block is determined to be an abnormal stop and the automatic recovery is not performed. In the case of transient shut-off pressure detection such as headwind, the air conditioner is not abnormally stopped.

  On the other hand, the operation in the case of receiving back wind from the blowing direction of the outdoor blower 10 will be described. During the cooling operation, the wind blows from the outdoor blowing direction, the pressure rises, exceeds the cutoff pressure of the pressure circuit breaker 11, and temporarily stops (T1). In the second operation exceeding the cut-off pressure once, the actuator control of the outdoor blower 10 or the compressor 1 or the electronic expansion valve 4 is performed so that the operation is performed at the operation pressure B lower than the normal operation pressure.

  When a stronger back wind is received from this state, the pressure circuit breaker 11 detects the breaking pressure again and enters the second operation stop (T2). In the third operation, operation is further reduced to the operating pressure A (operating pressure A <operating pressure B), and even if a reverse wind blows at the same level as the previous pressure increase (T3), the pressure breaker 11 is shut off. It is possible to operate without increasing the pressure.

  After that, since there are no three abnormal stops during Δτ1 after the first abnormal stop at T4, even if the pressure rises again to the shut-off pressure of the pressure circuit breaker 11, it does not stop abnormally. When T4 is reached, the operating pressure is returned to B. After that, if the reverse wind stops blowing and the pressure circuit breaker 11 does not detect the cut-off pressure during Δτ2, the operation is returned to the normal operation pressure (T5).

The flow of control is summarized by the flowchart of FIG.
A cooling operation is performed (step S41), and operation is performed at a normal operation pressure (step S42). When the back wind blows on the outdoor unit 30 during the cooling operation (step S43), it is determined whether the pressure circuit breaker 11 has detected the shutoff pressure (step S44). The outdoor blower rotation speed is increased, the compressor rotation speed is decreased, or the electronic expansion valve opening is increased (step S45), and operation is performed at the operating pressure B (step S46).

  Next, it is determined whether Δτ2 hours have elapsed since the previous break of the pressure circuit breaker 11 (step S47). If Δτ2 hours have elapsed, the outdoor fan speed is reduced, the compressor speed is increased, or the electronic expansion valve opening is decreased. (Step S55), the process returns to step S42.

  If Δτ2 hours have not elapsed in step S47, it is determined whether the pressure circuit breaker 11 has detected the breaking pressure again (step S48). If not detected, the process returns to step S46. If detected, once the operation is stopped, the outdoor fan speed is increased, the compressor speed is decreased, or the electronic expansion valve opening is increased (step S49), and the operating pressure A (operating pressure A <operating pressure B) is controlled. ) (Step S50).

  It is determined whether Δτ1 hour has elapsed since the last interruption of the pressure circuit breaker 11 (step S51). If Δτ1 hour has elapsed, the control of the outdoor fan speed reduction, the compressor speed increase, or the electronic expansion valve opening degree control is performed. Perform (step S52) Return to step S46.

  If Δτ1 hour has not elapsed in step S51, it is determined whether the pressure circuit breaker 11 has detected the breaking pressure again (step S53). If not detected, the process returns to step S50. If detected, the air conditioner is abnormally stopped (step S54).

  In this way, by changing the operating pressure according to the shutoff frequency of the pressure breaker 11, the degree of influence of condensation inhibition by the backwind on the outdoor blower 10 under the condition where the outdoor unit 30 is installed is indirectly detected, and the backwind As a result, it is possible to suppress the possibility of erroneous detection of abnormal stop due to the above, and to suppress the deterioration of the noise value due to the increase in the rotational speed of the outdoor blower 10 and the decrease in capacity due to the decrease in the frequency of the compressor 1.

  Although the description has been given of the occurrence of an abnormality in the fan block, the above control can also be applied when the pressure rapidly increases due to clogging of the refrigerant circuit.

Embodiment 4 FIG.
FIG. 15 shows the fourth embodiment and is a control flowchart.
In the third embodiment, if the operation of the pressure circuit breaker 11 is a false detection due to a back wind, and the erroneous detection is repeated, the pressure breaker 11 is controlled not to operate even in the case of a back wind by reducing the operating pressure. However, in the present embodiment, a plurality of outdoor units 30 are installed close to each other, and during the cooling operation, high-temperature air exchanged with the outdoor heat exchanger 3 is blown out from the outdoor unit 30. The high-temperature blown air hits another nearby outdoor unit 30, the temperature of the outdoor unit 30 rises, the temperature of the outdoor heat exchanger 3 rises, and the control for raising the operation condensing temperature. It is.

  The control flow in this case is as shown in FIG. 15, but FIG. 15 is different only in step S <b> 56 (the influence of the blowout of the nearby outdoor unit 30), and the description is omitted.

  Also in this case, by changing the operating pressure according to the shutoff frequency of the pressure breaker 11, the influence of condensation inhibition due to the blowout of the nearby outdoor unit 30 on the outdoor blower 10 under the conditions where the outdoor unit 30 is installed. Indirectly detecting the degree to suppress the possibility of abnormal stop false detection due to the influence of the blowout of the nearby outdoor unit 30 as much as possible, the deterioration of the noise value due to the increase in the rotational speed of the outdoor blower 10, the frequency of the compressor 1 It is possible to suppress a decrease in capacity due to a decrease.

  The present invention relates to a split type air conditioner in which an indoor unit and an outdoor unit such as a home or commercial air conditioner using an HFC410A refrigerant are separated, and a connection used in an air conditioner using an HCFC22 refrigerant It can be used when diverting piping.

It is a figure which shows Embodiment 1, and is a simplified diagram which shows the structure of the air conditioner of control object. It is a figure which shows Embodiment 1, and is a perspective view which shows the state by which the indoor unit and the outdoor unit were connected by connection piping. It is a figure which shows Embodiment 1, and is a figure which shows the refrigerant circuit and control circuit of an air conditioner. It is a figure which shows Embodiment 1 and is a conceptual diagram of a control part. FIG. 5 is a diagram illustrating the first embodiment and is a block diagram illustrating an inverter driving device. It is a figure which shows Embodiment 1, and is a figure which shows the characteristic of an alternative refrigerant | coolant. It is a figure which shows Embodiment 1, and is a figure which shows the state which a back wind blows in an outdoor unit. It is a figure which shows Embodiment 1, and is a figure which shows the pressure (condensation temperature) in air_conditionaing | cooling operation. It is a figure which shows Embodiment 1, and is a flowchart figure which shows operation | movement. It is a figure which shows Embodiment 2, and is a figure which shows the example with which multiple outdoor units are installed in proximity. It is a figure which shows Embodiment 3, and is a refrigerant circuit figure of an air conditioner. It is a figure which shows Embodiment 3, and is a figure which shows the change of the discharge pressure at the time of air_conditionaing | cooling operation. It is a figure which shows Embodiment 3, and is a flowchart figure of the control at the time of a fan block. It is a figure which shows Embodiment 3, and is a flowchart figure of the control at the time of a headwind. It is a figure which shows Embodiment 4, and is a flowchart of control.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Outdoor heat exchanger, 4 Electronic expansion valve, 5 Connection piping, 6 Indoor heat exchanger, 7 Connection piping, 8 Accumulator, 9 Indoor blower, 10 Outdoor blower, 11 Pressure circuit breaker, 12 Outdoor heat exchanger temperature detection means, 13 indoor heat exchanger temperature detection means, 14 control unit, 15 inverter circuit, 16 phase control unit, 18 converter circuit, 19 converter control unit, 17 timer, 20 indoor unit, 21 power supply, 30 Outdoor unit.

Claims (1)

A compressor, a four-way valve, an outdoor heat exchanger, an electronic expansion valve, a pressure breaker connected to the discharge side of the compressor, an outdoor unit having an outdoor blower, and
An indoor heat exchanger, an indoor unit having an indoor blower, and
An existing connection pipe connecting the outdoor unit and the indoor unit;
Refrigeration cycle having a compressor, a four-way valve, an outdoor heat exchanger, an electronic expansion valve, an indoor heat exchanger of the indoor unit, and the connecting pipe, and using a low-boiling refrigerant as a refrigerant and a non-chlorine refrigerant. When,
A high pressure side pressure detecting means for detecting a high pressure side pressure during cooling operation of the refrigeration cycle,
The pressure breaker, the breaking pressure for stopping the operation of the air conditioner is set to be less than the allowable pressure of the existing connection pipe,
When the high pressure side pressure detected by the high pressure side pressure detection means is higher than the limited high pressure side pressure set lower than the cutoff pressure of the pressure circuit breaker, the compressor or the outdoor blower or the electronic expansion valve is turned on. Control, lower the high-pressure side pressure until it reaches the target value,
An air conditioner that is controlled to increase the high-pressure side pressure within a range that does not exceed the restricted high-pressure side pressure unless the restricted high-pressure side pressure is exceeded for a certain time.

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