JP2012247182A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner, capable of eliminating any human-induced determination from the power activation to the start of the compressor to reduce the possibility of failure of a compressor, and capable of shortening the time thereof to ensure the operational degree of freedom.SOLUTION: In the multi-type air conditioner 1, a plurality of indoor units 11A, 11B are connected in parallel with at least one outdoor unit 3. A control unit 51 for controlling the operation has a compressor protection control mode 53, for determining the possibility of failure of a compressor 13 accompanying start upon the power activation to inhibit the start of the compressor 13 if the possibility is high and permit the start of the compressor 13 if the possibility is low. The compressor protection control mode determines that the possibility of the failure of the compressor 13 is low if the outside air temperature is equal to or higher than the predetermined temperature, and the predetermined temperature is set to be lower in the heating operation than in the cooling operation.

Description

  The present invention relates to an air conditioner.

The multi-type air conditioner is configured by connecting a plurality of indoor units in parallel to one outdoor unit (see Patent Document 1).
Such a multi-type air conditioner is used, for example, in a place having a large number of rooms (indoor unit installation locations) such as a building, so that the distance between the outdoor unit and the indoor unit becomes long. Together with this, the length of the pipe connecting each indoor unit and the outdoor unit becomes long, so that the amount of refrigerant to be sealed increases.
For this reason, since the amount of liquid refrigerant returning to the compressor side inevitably increases, the possibility that it will return to the compressor increases.
When this liquid refrigerant returns to the compressor, the compressor performs liquid compression. Such liquid compression may overload the compressor and lead to failure such as seizure.

Therefore, various devices have been proposed and used in order to prevent the liquid refrigerant from returning to the compressor.
For example, it has been avoided by installing a large-capacity accumulator that separates gas and liquid and stores liquid refrigerant on the suction side of the compressor.
For this reason, it is necessary to secure a space for installing a large accumulator in the outdoor unit, which has become a bottleneck in reducing the size and size of the outdoor unit. In addition, it has been difficult to reduce or eliminate the accumulator and reduce the cost.

JP 2007-40563 A

By the way, it is easy to occur that the compressor is liquid-compressed especially at the start-up at a low outside temperature. Therefore, before starting the compressor, the compressor main body is heated by a heater for a certain time, for example, 6 hours with a margin. It is recommended to keep warm.
Thus, if the power is turned on 6 hours before the start of the compressor, the compressor cannot be operated during that time.
The interior work of a building is carried out near the completion of the building, and is often performed in a situation where there is not enough time, and the installation work and trial operation of the multi-type air conditioner installed there are also performed without time. Often. For this reason, there is a possibility that the schedule may be hindered if 6 hours, which is a start-up preparation time with a margin, is secured.

In such a case, the time to start up the compressor may be consciously shortened, or it may be unavoidably shortened in order to forget to turn on the power and keep the test run schedule.
In this way, if the start-up preparation time is shortened due to human factors, the compressor may break down. On the other hand, if the recommended start-up preparation time is secured, the installation work and commissioning work schedules will be hindered. There is a risk of coming.

  In view of such circumstances, the present invention eliminates human judgment from power-on to compressor start-up, reduces the possibility of compressor failure, and shortens the time between them, thereby increasing operational flexibility. An object is to provide an air conditioner that can be secured.

In order to solve the above problems, the present invention employs the following means.
That is, the air conditioner according to the present invention is an air conditioner in which one or a plurality of indoor units are connected in parallel to at least one outdoor unit, and the controller controls the operation. Determines the possibility of a compressor failure at startup when the power is turned on, prohibits the start of the compressor if the possibility is high, and allows the start of the compressor if the possibility is low A protection control mode is provided, and the compressor protection control mode determines that if the outside air temperature is equal to or higher than a predetermined temperature, it is determined that the compressor is less likely to fail. It is characterized by being set lower than driving.

According to the present invention, when the power of the air conditioner is turned on, the compressor protection control mode functions. Further, for example, a heater for heating the compressor is energized. Compressor protection control mode determines the possibility of compressor failure at startup, prohibits startup of the compressor when the possibility is high, and allows startup of the compressor when the possibility is low become. In other words, the compressor cannot be started unless the compressor protection control mode is allowed.
In this way, the compressor protection control mode determines whether or not the compressor can be started, and unless it allows it, the compressor will not be started. It is not possible to prevent the compressor from being broken.

Also, when the compressor is unlikely to break down, the compressor can be started even if a certain amount of time has not elapsed, so the time can be shortened compared to waiting for the passage of a certain amount of time. . Thereby, the freedom degree of operation | use of an air conditioner, especially a multi-type air conditioner is securable.
Note that the possibility that the compressor will fail is determined by whether or not the temperature inside the compressor is high. That is, when the temperature inside the compressor is high, it can be estimated that the liquid refrigerant is evaporated and discharged to the outside of the compressor, and it can be determined that the possibility that the compressor will fail is low. In this case, directly measuring the internal temperature requires installing a new expensive measuring instrument, which is costly. Therefore, it is preferable to use an existing measuring instrument.

  Further, in the compressor protection control mode, if the outside air temperature is equal to or higher than a predetermined temperature, it is determined that the possibility that the compressor will fail is low.

Since the compressor has a temperature substantially equal to the outside air temperature, when the outside air temperature is high, the temperature inside the compressor, that is, the compressor, is also high. If the temperature of the compressor is high, it can be estimated that the liquid refrigerant is evaporated and discharged out of the compressor, or the liquid refrigerant easily evaporates and has little adverse effect on the compressor, so the compressor breaks down It can be determined that the possibility is low.
The predetermined temperature is 5 to 15 ° C in the cooling operation, and preferably 20 to 30 ° C. In the case of heating operation, the temperature is set to -5 to 5 ° C, preferably 10 to 20 ° C. The heating operation is set lower than the cooling operation. This is because in the heating operation, the pipes after the evaporator are shorter than in the cooling operation, and the amount of refrigerant that accumulates in the piping is small.

  In the above invention, the compressor protection control mode is such that the temperature obtained by subtracting the saturation temperature of the refrigerant at the low pressure of the refrigerant sucked into the compressor from the external temperature at the refrigerant suction position of the compressor is equal to or higher than a predetermined temperature. In this case, it may be determined that the compressor is unlikely to break down.

  In the above invention, the compressor protection control mode may determine that the compressor is less likely to fail if the external temperature of the compressor is maintained at a predetermined temperature or higher for a predetermined time. Good.

When the external temperature of the compressor increases, the amount of heat is transferred to the inside of the compressor, so that the temperature inside the compressor also increases over time. Therefore, when the state where the external temperature of the compressor is equal to or higher than the predetermined temperature continues for a predetermined time, the temperature inside the compressor also becomes equal to or higher than the predetermined temperature.
If the temperature inside the compressor rises, it can be estimated that the liquid refrigerant is evaporated and discharged outside the compressor, or the liquid refrigerant evaporates easily and has little adverse effect on the compressor, causing the compressor to malfunction. It is possible to determine that there is a low possibility of doing this.
The predetermined temperature is 5 to 15 ° C in the cooling operation, and preferably 20 to 30 ° C. In the case of heating operation, the temperature is set to -5 to 5 ° C, preferably 10 to 20 ° C. The heating operation is set lower than the cooling operation. This is because in the heating operation, the pipes after the evaporator are shorter than in the cooling operation, and the amount of refrigerant that accumulates in the piping is small.
The predetermined time varies depending on the size of the compressor, but is 3 to 6 hours in consideration of the time until the temperature outside the compressor is transmitted to the inside.

  Moreover, in the said invention, the said compressor protection control mode is good also as determining with the possibility that the said compressor will be low if the energization time of the heater which heats the said compressor continues for the predetermined time.

  When the compressor is heated by the heater, the amount of heat is transmitted to the inside of the compressor, so that the temperature inside the compressor gradually increases as time elapses. Therefore, if the heating by the heater continues for a predetermined time, it can be estimated that the liquid refrigerant evaporates inside the compressor and is discharged to the outside of the compressor, or the liquid refrigerant evaporates easily and has a low adverse effect on the compressor. Therefore, it can be determined that the compressor is unlikely to fail.

  Moreover, in the said invention, the said control part may be provided with the cancellation | release means which cancels | releases the said compressor protection control mode and enables the said compressor to start.

According to the present invention, when the release means is operated, the compressor protection control mode is released and the compressor can be arbitrarily started. For example, during the trial operation, the compressor is started at the operator's discretion. be able to.
As a result, it is possible to further secure a degree of freedom in operation such as shortening the startup preparation time of the compressor.

According to the present invention, the controller that controls the operation determines the possibility that the compressor will break down when the power is turned on, and if the possibility is high, the start of the compressor is prohibited and the possibility is low. In this case, since the compressor protection control mode that allows the start of the compressor is provided, the start of the compressor cannot be arbitrarily started by human judgment, and the risk of the compressor being damaged can be suppressed. it can.
In addition, since it is possible to shorten the start-up preparation time as compared to waiting for the passage of a certain time, it is possible to ensure the freedom of operation of the air conditioner, particularly the multi-type air conditioner.

It is a refrigerating cycle figure of the multi type air harmony machine concerning one embodiment of the present invention. It is a flowchart of the compressor protection control mode in the multi-type air conditioner concerning one Embodiment of this invention. It is a flowchart which shows another embodiment of the compressor protection control mode in the multi-type air conditioner concerning one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a refrigerant cycle diagram of a multi-type air conditioner (air conditioner) 1 according to the present embodiment.
The multi-type air conditioner 1 includes a single outdoor unit 3, a gas side pipe 5 and a liquid side pipe 7 led out from the outdoor unit 3, and a branching device between the gas side pipe 5 and the liquid side pipe 7. 9, a plurality of indoor units 11 </ b> A and 11 </ b> B connected in parallel via 9.

  The outdoor unit 3 includes an inverter-driven compressor 13 that compresses refrigerant, an oil separator 15 that separates lubricating oil from refrigerant gas, a four-way switching valve 17 that switches a circulation direction of the refrigerant, and refrigerant and outside air. An outdoor heat exchanger 19 for heat exchange, a supercooling coil 21 integrally formed with the outdoor heat exchanger 19, an outdoor electric expansion valve (EEVH) 23 for heating, a receiver 25 for storing liquid refrigerant, A supercooling heat exchanger 27 that supercools the liquid refrigerant, a supercooling electric expansion valve (EEVSC) 29 that controls the amount of refrigerant that is diverted to the supercooling heat exchanger 27, and a refrigerant gas that is drawn into the compressor 13 A small-capacity accumulator 31 that separates the liquid component from the inside and stores the liquid refrigerant, a gas side operation valve 33, and a liquid side operation valve 35 are provided.

  Below the compressor 13, a ring-shaped heater 14 is installed in the vicinity of the compressor 13. The heater 14 is configured to be energized when the multi-type air conditioner 1 is turned on, and is energized or de-energized as necessary after energization.

As known, these are connected via refrigerant pipes such as a discharge pipe 37A, a gas pipe 37B, a liquid pipe 37C, a gas pipe 37D, a suction pipe 37E, and a branch pipe 37F for supercooling to constitute an outdoor refrigerant circuit 39. doing.
The outdoor unit 3 is provided with an outdoor fan 41 that blows outside air to the outdoor heat exchanger 19.

The gas side pipe 5 and the liquid side pipe 7 are refrigerant pipes connected to the gas side operation valve 33 and the liquid side operation valve 35 of the outdoor unit 3.
The lengths of the gas side pipe 5 and the liquid side pipe 7 are appropriately determined according to the distance between the outdoor unit 3 and the indoor units 11A and 11B connected to the outdoor unit 3 at the time of installation on site.
An appropriate number of branching devices 9 are provided in the middle of the gas side piping 5 and the liquid side piping 7, and an appropriate number of indoor units 11 </ b> A and 11 </ b> B are connected via the branching devices 9.
Thereby, one sealed refrigeration cycle 43 is formed.

The indoor units 11A and 11B include an indoor heat exchanger 45 that exchanges heat between the refrigerant and room air for indoor air conditioning, an indoor electric expansion valve (EEVC) 47 for cooling, and an indoor heat exchanger 45 through the indoor heat exchanger 45. And an indoor fan 49 for circulating air.
The indoor units 11A and 11B are connected to the branching device 9 via a branch gas pipe 5A and a branch liquid pipe 7A on the indoor side.

The multi-type air conditioner 1 is provided with a control unit 51 that controls its operation. The control unit 51 is provided with a compressor protection control mode 53 that restricts activation of the compressor 13 when the multi-type air conditioner 1 is turned on and protects the compressor 13.
Further, the control unit 51 is provided with a release means 55 that releases the compressor protection control mode 53 and enables the compressor 13 to be started.

A lower dome temperature sensor 57 that measures an external temperature of the main body (dome) of the compressor 13 is provided at a lower central portion of the compressor 13.
The discharge pipe 37 </ b> A is provided with a high-pressure sensor 59 that measures the pressure of the high-pressure refrigerant gas discharged from the compressor 13.
The suction pipe 37E is provided with a low-pressure sensor 61 that measures the pressure of the low-pressure refrigerant gas sucked into the compressor 13.

On the outside air intake side of the outdoor heat exchanger 19, an outside air temperature sensor 63 for measuring the temperature of the outside air taken in is provided.
On the indoor air intake side of the indoor heat exchanger 45, an indoor air temperature sensor 65 that measures the temperature of the indoor air taken in is provided.
The indoor heat exchanger 45 is provided with a heat exchange temperature sensor 67 for measuring the temperature of the heat exchange member.

In the multi-type air conditioner 1 described above, the cooling operation is performed as follows.
The high-temperature and high-pressure refrigerant gas compressed by the compressor 13 is discharged to the discharge pipe 37A. The refrigerant gas is circulated to the gas pipe 37 </ b> B side by the four-way switching valve 17 after the lubricating oil contained in the refrigerant is separated by the oil separator 15.
The refrigerant gas passing through the gas pipe 37B is heat-exchanged with the outside air blown by the outdoor fan 41 in the outdoor heat exchanger 19 to be condensed and liquefied to be a liquid refrigerant.
The liquid refrigerant is cooled by the supercooling coil 21, passes through the outdoor electric expansion valve 23, and is temporarily stored in the receiver 25 to adjust the circulation amount.

The liquid refrigerant from the receiver 25 partially flows into the subcooling branch pipe 37F in the process of passing through the supercooling heat exchanger 27 via the liquid pipe 37C and is adiabatically expanded by the supercooling electric expansion valve (EEVSC) 29. Heat exchange with the refrigerant is performed to cool to a predetermined degree of supercooling.
The liquid refrigerant to which a predetermined degree of supercooling is given is led out from the outdoor unit 3 to the liquid side pipe 7 via the liquid side operation valve 35. The liquid refrigerant led out to the liquid side pipe 7 is diverted to the branch liquid pipes 7A and 7B of the indoor units 11A and 11B by the branching unit 9.

The liquid refrigerant branched into the branch liquid pipes 7A and 7B is adiabatically expanded by the indoor electric expansion valve (EEVC) 47 and flows into the indoor heat exchanger 45 as a gas-liquid two-phase flow.
In the indoor heat exchanger 45, heat is exchanged between the indoor air circulated by the indoor fan 49 and the refrigerant, and the indoor air is cooled and provided for indoor cooling.
On the other hand, the refrigerant is gasified, reaches the branching device 9 through the branch gas pipes 5A and 5B, and merges with the refrigerant gas from the other indoor units in the gas side pipe 5.

The refrigerant gas merged in the gas side pipe 5 returns to the outdoor unit 3 again, and reaches the suction pipe 37E through the gas side operation valve 33, the gas pipe 37D, and the four-way switching valve 17. The refrigerant gas merges with the refrigerant gas from the branch pipe 37 </ b> F and is introduced into the accumulator 31.
In the accumulator 31, the liquid component contained in the refrigerant gas is separated, only the gas component is sucked into the compressor 13, and the refrigerant is compressed again in the compressor 13.
The cooling operation is performed by repeating the above cycle.

On the other hand, the heating operation is performed as follows.
The high-temperature and high-pressure refrigerant gas compressed by the compressor 13 is discharged to the discharge pipe 37A. This refrigerant gas is circulated to the gas pipe 37 </ b> D side by the four-way switching valve 17 after the lubricating oil contained in the refrigerant is separated by the oil separator 15.
The refrigerant is led out from the outdoor unit 3 through the gas side operation valve 33 and the gas side pipe 5, and is further introduced into the indoor units 11A and 11B through the branching unit 9 and the indoor side branch gas pipes 5A and 5B.
The high-temperature and high-pressure refrigerant gas introduced into the indoor units 11A and 11B is heat-exchanged with the indoor air circulated by the indoor fan 49 in the indoor heat exchanger 45, and the indoor air is heated and used for indoor heating.

On the other hand, the liquid refrigerant cooled and condensed and liquefied by the indoor air reaches the branching device 9 via the indoor electric expansion valve (EEVC) 47 and the branch liquid pipes 7A and 7B, and is merged with the refrigerant from other indoor units. Then, it returns to the outdoor unit 3 through the liquid side pipe 7.
During heating, in the indoor units 11A and 11B, the opening degree of the indoor electric expansion valve (EEVC) 47 is controlled so that the degree of subcooling of the refrigerant at the outlet of the indoor heat exchanger 45 functioning as a condenser becomes a constant value. Is done.

The liquid refrigerant returned to the outdoor unit 3 reaches the supercooling heat exchanger 27 via the liquid side operation valve 35. Thereafter, the liquid refrigerant flows into the receiver 25 and is temporarily stored, and the circulation amount is adjusted.
This liquid refrigerant reaches the outdoor electric expansion valve (EEVH) 23 through the liquid pipe 37C, where it is adiabatically expanded and flows into the outdoor heat exchanger 19 through the supercooling coil 21.
In the outdoor heat exchanger 19, heat is exchanged between the outside air blown by the outdoor fan 41 and the refrigerant, and the refrigerant absorbs heat from the outside air and is evaporated.

This gas refrigerant is introduced from the outdoor heat exchanger 19 into the accumulator 31 through the gas pipe 37B, the four-way switching valve 17, and the suction pipe 37E.
In the accumulator 31, the liquid component contained in the refrigerant gas is separated and only the gas component is sucked into the compressor 13, and the refrigerant is compressed again by the compressor 13.
A heating operation is performed by repeating the above cycle.

Next, the operation of the compressor protection control mode 53 will be described. FIG. 2 shows a flow of the cooling operation compressor protection control mode 53 used, for example, at the time of the cooling operation test operation after installing the multi-type air conditioner or at the start of the first cooling operation in the cooling season.
When the power is turned on (step S1), the heater 14 is energized, and the compressor 13 is heated by the amount of heat.
Further, it is determined whether or not the release means 55 is turned on (step S2).

If the release means 55 is ON (YES), the start of the compressor 13 is permitted (step S3). The activation permission is notified to the worker by, for example, displaying on the display of the operation table that the activation is permitted and / or notifying by voice.
When the compressor 13 is started in this state, the compressor protection control mode 53 is ended (step S4).

In this way, when the release means 55 is turned on, the compressor 13 can be activated arbitrarily, so that, for example, the compressor 13 can be activated based on the judgment of the operator during the trial operation.
Thereby, the freedom degree in operation | use of the multi-type air conditioner 1 can be expanded, such as shortening the starting preparation time of the compressor 13. FIG.

If the release means 55 is not turned on (NO), it is determined whether or not the outside air temperature measured by the outside air temperature sensor 63 is 10 ° C. or higher (step S5).
When the outside air temperature is 10 ° C. or higher (YES), the process proceeds to step S3, and the start of the compressor 13 is permitted.
That is, if the outdoor unit 3 is left for a certain period of time, the outdoor unit 3 is in an equilibrium state, and the internal temperature of the compressor 13 is estimated to be substantially the same as the outside air temperature. It will be 10 ° C or higher.
If the internal temperature of the compressor 13 is 10 ° C. or higher, it can be estimated that the liquid refrigerant is evaporated and discharged to the outside of the compressor 13, or the liquid refrigerant is easily evaporated and has little adverse effect on the compressor 13. Therefore, it can be determined that the compressor 13 is unlikely to fail.

In addition, this 10 degreeC shows a preferable example, and this temperature is suitably selected in the range of 5-15 degreeC in the case of a cooling operation, for example. Moreover, it is preferable to select in the range of 20-30 degreeC since the possibility of a failure can be suppressed more reliably.
Further, in the heating operation, the piping after the evaporator is shorter than the cooling operation, and the amount of refrigerant accumulated therein is small, so the amount of liquid refrigerant flowing into the compressor 13 is small. For this reason, since the bad influence of a liquid refrigerant becomes small, the temperature used for determination in Step S5 can be made low. This temperature is selected, for example, in the range of −5 to 5 ° C., and preferably appropriately selected in the range of 10 to 20 ° C.

If the outside air temperature is less than 10 ° C. in step S5 (NO), it is determined whether the degree of superheat under the dome is 15 ° C. or more (step S6).
The degree of superheat under the dome is the refrigerant at the low pressure of the refrigerant sucked into the compressor 13 measured by the low pressure sensor 61 from the external temperature of the compressor 13 measured by the dome temperature sensor 57, that is, the lower temperature of the compressor 13. The saturation temperature of is subtracted.

In step S6, when the degree of superheat below the dome is 15 ° C. or more (YES), the process proceeds to step S3 and the start of the compressor 13 is permitted.
When the external temperature of the compressor 13 increases, the amount of heat is transmitted to the inside of the compressor 13, so that the temperature inside the compressor 13 also increases with time. On the other hand, when the internal temperature is high, the external temperature is also high. From this, it can be estimated that the external temperature of the compressor 13 is substantially equal to the internal temperature of the compressor 13.

Accordingly, the fact that the degree of superheat under the dome is large has a sufficient amount of heat for the refrigerant sucked into the compressor 13 (for example, it can be evaporated even if it flows in liquid). Can be estimated. For this reason, for example, if the degree of superheat under the dome is 15 degrees or more, it can be determined that the possibility that the compressor will fail is low.
Note that the degree of superheat under the dome, which is determined that the compressor is unlikely to break down, is appropriately selected, for example, in the range of 10 to 15 ° C, preferably in the range of 10 to 40 ° C.

In this embodiment, it is determined whether or not the compressor 13 has a low possibility of failure due to the degree of superheat under the dome. However, in the same meaning, the external temperature of the compressor 13 measured by the under-dome temperature sensor 57 ( It may be determined using the temperature under the dome.
As described above, since the external temperature of the compressor 13 can be estimated to be substantially equal to the temperature inside the compressor 13, the amount of heat inside the compressor 13 can be estimated. Thus, when the external temperature becomes equal to or higher than a predetermined temperature, the start of the compressor 13 is permitted. As this temperature, for example, an appropriate temperature is appropriately selected in the range of 0 to 10 ° C, preferably in the range of 20 to 30 ° C.

In addition, since it takes time for the external heat amount to reach the inside, it is preferable to include that the predetermined temperature is continued for an appropriately selected time as a determination condition. This time is, for example, 3 to 6 hours.
Further, the suction superheat degree of the compressor 13 is determined by dividing the refrigerant saturation temperature at the low pressure of the refrigerant sucked into the compressor 13 measured by the low pressure sensor 61 from the suction pipe temperature of the compressor 13. Also good.

If the degree of superheat under the dome is less than 15 ° C. in step S6 (NO), it is determined whether or not a predetermined time, for example, 6 hours has elapsed after the power is turned on (step S7).
Therefore, in step S7, when 6 hours have passed (YES), the process proceeds to step S3 and the start of the compressor 13 is permitted.

Since the compressor 13 is heated by the heater 14, the external temperature thereof is raised sequentially. When the external temperature rises, the amount of heat is transmitted to the inside of the compressor, so that the temperature inside the compressor gradually increases as time elapses.
Therefore, if heating by the heater 14 continues for a predetermined time, it can be estimated that the liquid refrigerant evaporates inside the compressor 13 and is discharged outside the compressor, or the liquid refrigerant evaporates easily and adversely affects the compressor 13. Therefore, it can be determined that the compressor 13 is unlikely to fail.
This 6 hours is an example, and the predetermined time is appropriately selected as the time required for the compressor 13 to be heated by the heater 14 and to have a sufficient amount of heat.

  On the other hand, if 6 hours have not elapsed (NO) in step S7, the start of the compressor 13 is prohibited (step S8). Thereafter, returning to step S5, the above-described procedure is repeated. Further, it may be notified to the worker by displaying on the display of the operation table that the start of the compressor 13 is prohibited and / or notifying by voice. Further, the time until activation is permitted may be estimated and displayed on the display.

  This prohibition prevents the compressor 13 from starting even if the start of the compressor 13 is instructed. Therefore, when starting of the compressor 13 is prohibited in the compressor protection control mode 53, the compressor 13 cannot be started unless the release means 55 is turned ON, for example.

Thus, since the compressor protection control mode 53 determines whether or not the compressor 13 can be started and does not allow it, the compressor 13 is not started. Startup is not possible.
Therefore, since the compressor 13 is not started in a state where there is a high possibility of failure, the risk of the compressor 13 being broken can be suppressed.

Further, in the present embodiment, the compressor 13 is satisfied if any one of the conditions that the outside air temperature is 10 ° C. or higher, the degree of superheat under the dome is 15 ° C. or higher, and 6 hours have elapsed after the power is turned on is satisfied. Will be allowed to start.
When the compressor has a low possibility of failure, that is, when the outside air temperature is 10 ° C. or higher, or when the superheat degree under the dome is 15 ° C. or higher, the compressor 13 can be started even if a certain time has not elapsed. Compared to waiting for a certain amount of time, the time can be shortened.
Thereby, the freedom degree of operation | use of the multi-type air conditioner 1 is securable.

The compressor protection control mode 53 is not limited to the flow shown in FIG. For example, it may be configured as shown in FIG.
FIG. 3 shows the flow of another embodiment of the compressor protection control mode 53.
In the flow shown in FIG. 3, if the outside air temperature is higher than the predetermined temperature (YES) in step S5, the process proceeds to step S6 instead of proceeding to step S3. If step S5 is NO, the process proceeds to step S7 instead of proceeding to step S6.

That is, in FIG. 3, about step S5 and step S6, unless both conditions are satisfy | filled, starting of the compressor 13 is not permitted.
Thus, since it is on the safer side, the individual conditions in steps S5 and S6 are slightly relaxed accordingly.

  In the present embodiment, the parallel air condition is that the outside air temperature is 10 ° C. or higher, the degree of superheat under the dome is 15 ° C. or higher, and 6 hours have elapsed after the power is turned on. One may be used as a condition, or any two of them may be used as a condition.

In the present embodiment, the start of the compressor 13 tends to be determined based on whether or not the amount of heat inside the compressor 13 is sufficient. In addition to this, the refrigerant distribution is considered in the determination. Also good.
That is, the refrigerant tends to accumulate at a low temperature. For example, by comparing the temperatures measured by the outside air temperature sensor 63 and the inside air temperature sensor 65, it can be determined whether there is a large amount of refrigerant on the outdoor unit 3 side or a large amount on the indoor units 11A and 11B side.

Further, by comparing the temperature of the outdoor heat exchanger 19 with the temperature of the indoor heat exchanger 45 measured by the heat exchange temperature sensor 67, there is a large amount of refrigerant on the outdoor unit 3 side, or the indoor units 11A and 11B side. You can see how many.
Further, the refrigerant amount on the outdoor unit 3 side can be estimated from the magnitude of the refrigerant saturation temperature at the refrigerant pressure measured by the high pressure sensor 59 and the low pressure sensor 61.

The present invention is not limited to the invention according to the above-described embodiment, and can be appropriately modified without departing from the gist thereof.
For example, although the multi-type air conditioner 1 is used in the above embodiment, the present invention can be applied to other types of air conditioners.
Further, the number of indoor units 11A and 11B may be any number as long as it is one or more, and is not particularly limited. The number of outdoor units 3 is not particularly limited as long as it is one or more.
Furthermore, it is needless to say that specific numerical values such as time and temperature exemplified in the above embodiment are merely examples, and are not limited thereto.

DESCRIPTION OF SYMBOLS 1 Multi type air conditioner 3 Outdoor unit 11A, 11B Indoor unit 13 Compressor 14 Heater 51 Control part 53 Compressor protection control mode 55 Release means

Claims (5)

An air conditioner in which one or a plurality of indoor units are connected in parallel to at least one outdoor unit,
The control unit that controls the operation determines the possibility that the compressor will break down upon startup when the power is turned on.If the possibility is high, the start of the compressor is prohibited, and if the possibility is low, the compressor Compressor protection control mode that allows starting of the compressor is provided,
The compressor protection control mode determines that if the outside air temperature is equal to or higher than a predetermined temperature, the compressor is unlikely to fail,
The air conditioner is characterized in that the predetermined temperature is set lower in the heating operation than in the cooling operation.   In the compressor protection control mode, when the temperature obtained by subtracting the saturation temperature of the refrigerant at the low pressure of the refrigerant sucked into the compressor from the external temperature at the refrigerant suction position of the compressor is equal to or higher than a predetermined temperature, the compression protection control mode is performed. The air conditioner according to claim 1, wherein the air conditioner is determined to have a low possibility of failure.   The compressor protection control mode determines that the compressor is unlikely to fail if a state where the external temperature of the compressor is equal to or higher than a predetermined temperature continues for a predetermined time. Item 3. An air conditioner according to Item 2.   4. The compressor protection control mode according to claim 1, wherein when the energization time of a heater for heating the compressor continues for a predetermined time, it is determined that the possibility of failure of the compressor is low. The air conditioner of any one of Claims.   The air according to any one of claims 1 to 4, wherein the control unit includes release means for releasing the compressor protection control mode and enabling the compressor to be started. Harmony machine.

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