JPH09287856A - Defrosting method for air-conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generations of noise and vibration when an air- conditioner is switched from heating operation to defrosting operation and to perform defrosting in a short time. SOLUTION: In this defronsting method for an air-conditioner comprising a plurality of outdoor machines, provided the outdoor machine of a plurality of the outdoor machines satisfies a condition to effect defrosting, by starting defrosting operation, in order, of all the outdoor machines at intervals of a given time, noise and vibration of the outdoor machine generated when an air-conditioner is switched to defrosting operation are divided at time intervals and not centralized at one time, whereby an effect to prevent the generation of high noise and vibration is produced. Further, since defrosting operation of all the outdoor machines is collectively effected, there is no need to perform frequent defrosting operation owing to defrosting of each outdoor machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrosting method for an air conditioner including a plurality of outdoor units.

[0002]

2. Description of the Related Art Generally, in an air-cooled heat pump heating system, the outdoor heat exchanger may be frosted depending on the outside air and the operating state. Defrosts.

Conventionally, in the defrosting method for an air conditioner composed of a plurality of outdoor units, if there is one that satisfies the defrosting conditions, the outdoor units are individually defrosted and the outdoor units are not related to each other. Was the main.

In recent years, with the improvement of control technology, there has been a method of collectively defrosting all of a plurality of outdoor units if a certain condition is satisfied. For example, JP-A-6-31
As disclosed in Japanese Patent No. 3653, if there is at least one outdoor unit to be defrosted among a plurality of outdoor units, the defrosting operation of all the outdoor units is started at the same time. There is a frost method.

A defrosting method for an air conditioner including a plurality of conventional outdoor units will be described below with reference to the drawings.

FIG. 4 is a flowchart of a conventional defrosting method for an air conditioner including a plurality of outdoor units.

When the heating operation switch is input, the heating operation is started in the first step 101, and then the process proceeds to the second step 103, in which there is only one outdoor unit to be defrosted. To determine. If there is an outdoor unit to be defrosted, the process proceeds to the third step 105. On the other hand, when there is no outdoor unit to be defrosted, the process returns to the first step 101.

In the third step 105, the variable compressor is set to the full operation, and then in the fourth step 107, all the outdoor units are switched to the defrosting operation. Fifth step 10
In 9, the defrosting is sequentially ended from the outdoor unit that satisfies the defrosting condition, and the heating operation is switched to.

In the sixth step 111, it is judged whether or not all the outdoor units have completed the defrosting operation. If all the outdoor units have completed the defrosting operation, the process proceeds to the seventh step 113,
After releasing the full operation of the variable compressor, the first step 10
Return to 1 and perform normal heating operation. On the other hand, when the defrosting operation of all the outdoor units is not completed, the process returns to the third step 105.

By using such a defrosting method,
When at least one of the plurality of outdoor units is in the defrosting state, the defrosting operation of all the outdoor units is started at the same time. Therefore, since it is only necessary to switch the ventilation of the indoor unit once with the defrosting operation, this switching noise does not become a noise.

[0011]

Generally, as a defrosting method, a reverse cycle system in which a four-way valve is switched to change from a heating cycle to a cooling cycle, and a bypass circuit is used without switching the four-way valve to discharge gas from a compressor. The hot gas defrosting method with the forward cycle of sending directly to the outdoor heat exchanger is often used, but in either method, the four-way valve or the hot gas bypass valve is operated when the operation is switched from heating to defrosting. Since the flow of the refrigerant changes rapidly, refrigerant noise and pipe vibration occur during switching.

However, in the above-described conventional configuration, since the defrosting operation of all the outdoor units is started at the same time, the refrigerant noise and the pipe vibration generated from the plurality of outdoor units are concentrated at the same time when the defrosting is started. In addition, there is a drawback that the overall noise and pipe vibration increase.

The present invention is to solve the above-mentioned conventional problems, and to remove an air conditioner capable of defrosting a plurality of outdoor units without increasing noise and pipe vibration at the start of defrosting operation. The purpose is to provide a frost method.

[0014]

In order to achieve this object, the present invention provides a plurality of outdoor units that meet the defrosting conditions at predetermined time intervals for all the outdoor units. The feature is that the defrosting operation is started sequentially.

As a result, when the defrosting operation starts, the defrosting of the plurality of outdoor units is performed without the noise and the pipe vibration at the start of the defrosting of the plurality of outdoor units being concentrated and generated at one time. be able to.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is a defrosting method for an air conditioner comprising a plurality of outdoor units, wherein one of the plurality of outdoor units that satisfies the defrosting condition is satisfied. If there is, it is characterized by sequentially starting defrosting operation for all outdoor units at a predetermined time interval, which occurs due to switching of the four-way valve at the start of defrosting and operation of the hot gas bypass valve. Since noise and pipe vibration can be dispersed for each outdoor unit within a predetermined time, there is an effect that noise and pipe vibration at the start of defrosting of a plurality of outdoor units are not concentrated and generated at one time.

The invention described in claim 2 is, in addition to the invention described in claim 1, that when the defrosting operation is started, the defrosting operation is sequentially started in the order of priorities set in the control device in advance. If the priority is set in the control device in advance so that the outdoor unit that takes a long time to defrost starts the defrosting operation first, an outdoor unit that takes a lot of frost and takes a long time to defrost Since the defrosting of the machine can be completed earlier, there is an effect that the entire defrosting time can be further shortened in the control device that does not use a complicated arithmetic device.

According to a third aspect of the present invention, in addition to the first aspect, the temperatures of the heat exchangers of the plurality of outdoor units are detected at the start of the defrosting operation, and the outdoor units having the lowest temperatures are sequentially selected. By starting the defrosting, the defrosting of the outdoor unit, which has a large amount of frosting and takes a long time to defrost, can be ended earlier, so that the entire defrosting time can be further shortened.

An embodiment of a defrosting method for an air conditioner according to the present invention will be described below with reference to the drawings.
It should be noted that the same configurations as those of the related art are denoted by the same reference numerals and detailed description thereof will be omitted.

(Embodiment 1) FIG. 1 is a flowchart showing a defrosting method for an air conditioner according to Embodiment 1 of the present invention. FIG. 2 is a refrigerant circuit diagram of the air conditioner of the first embodiment.

In FIG. 2, 11 is an air conditioner, and 1
2, 13 are outdoor units, 14 and 15 are indoor units, 16 is a liquid pipe, 17 is a gas pipe, and a plurality of outdoor units 12, 13
Is connected to a plurality of indoor units 14 and 15 with a liquid pipe 16 and a gas pipe 17 of one system, and constitutes an air conditioner 11.

Reference numerals 18 and 19 denote compressors, 20 denotes compressors 18,
Accumulators 21, 22 connected to 19 are oil separators, respectively connected to compressors 18, 19, 23 is a four-way valve, 24 is an outdoor heat exchanger, 25 is an expansion valve, 26 is a temperature detector. Yes, it is stored in the outdoor units 12 and 13.

27 is an indoor heat exchanger, 28 is a blower, and 29 is
Is an indoor expansion valve and is housed in the indoor units 14 and 15.

Reference numeral 30 denotes a control device for the air conditioner 11, which is connected to the outdoor units 12 and 13 and the indoor units 14 and 15, and the defrosting priority is preset.
Set the priority of outdoor units in order of high expected frost. Here, the outdoor unit 12 is set to the first priority, and the outdoor unit 13 is set to the second priority.

The operation of the air conditioner configured as above will be described below. Four-way valve 2 during heating operation
3 is on the dotted line side, and the high-temperature and high-pressure refrigerant discharged from the compressor 18 and the compressor 19 of the plurality of outdoor units 12 and 13 passes through the oil separators 21 and 22, respectively, and is separated after the lubricating oil is collected. Through the four-way valve 23 to flow from the gas pipe 17 to the indoor units 14 and 15. Furthermore, the indoor units 14, 1
The air radiated and warmed by the indoor heat exchanger 27 of No. 5 is sent to the room by the blower 28. On the other hand, the heat-exchanged refrigerant is decompressed by the indoor expansion valve 29, passes through the liquid pipe 16 and the outdoor unit 1
It flows to 2, 13. The refrigerant flowing to the outdoor units 12 and 13 is
After the flow rate is adjusted by the outdoor expansion valve 25 and the temperature is detected by the temperature detector 26, the outdoor heat exchanger 24 absorbs heat on the air side by heat exchange and evaporates. Then, the liquid refrigerant is separated through the accumulator 20, and only the gas refrigerant is compressed by the compressor 18,
It returns to 19 and is circulated by being discharged again.

During the heating operation as described above, the outdoor heat exchanger may be frosted depending on the outside air and the operating state.
When frost forms, the efficiency of heating deteriorates. Therefore, when frost forms to some extent, defrosting is performed. Here, using the characteristic that the temperature detected by the temperature detector 26 decreases when frost forms,
When the detected temperature becomes equal to or lower than a predetermined temperature (for example, −10 ° C.), the defrosting start condition is satisfied and defrosting is started.

Here, the operation of the defrosting operation will be described with reference to FIG. First, in step 1, the heating operation is performed in the cycle described above. Next, in step 2, if the temperature detected by the temperature detector 26 is equal to or lower than a predetermined temperature (for example, -10 ° C) and at least one outdoor unit satisfies the defrosting start condition, the process proceeds to step 3, and if there is no outdoor unit, the step proceeds to step 3. Return to 1.

In step 3, the defrosting operation is sequentially started from the outdoor unit having the highest priority at predetermined time intervals. The priority order is preset in the control device 30, and here, for example, if the predetermined time is 5 seconds, the outdoor unit 12 first starts defrosting. The outdoor unit 12 switches the four-way valve 23 to set a cooling cycle. As a result, the refrigerant discharged from the compressor is
The outdoor heat exchanger radiates heat so defrosting can be performed. Next, at intervals of 5 seconds, the outdoor unit 13 similarly switches the four-way valve 23 to start defrosting. When switching the four-way valve 23,
Because the flow of the refrigerant changes, refrigerant noise and pipe vibration occur for 2 to 3 seconds after the switching, but since there is a 5-second time interval between the four-way valve switching of the outdoor unit 12 and the outdoor unit 13, this refrigerant noise and vibration occur. There is no overlap. In addition, the indoor units 14 and 15
The blower 28 is stopped when the first outdoor unit starts defrosting in order to prevent cold air from being blown out during the defrosting operation.

Next, at step 4, the outdoor unit that satisfies the defrosting termination condition switches the four-way valve 23 to terminate the defrosting and starts the heating operation. Here, the defrosting is ended when the temperature detected by the temperature detector 26 becomes equal to or higher than a predetermined temperature (for example, 10 ° C.).

At step 5, it is judged whether or not all the outdoor units have finished defrosting. If not, the procedure returns to step 4,
If completed, the process returns to step 1 to restart the heating operation, and the blowers 28 of the indoor units 14 and 15 also restart the blowing.

As described above, according to the defrosting method for the air conditioner according to the first embodiment, if any of the plurality of outdoor units 12 and 13 satisfies the defrosting condition, all the outdoor units are Since the defrosting operation is sequentially started at a predetermined time interval, noise and pipe vibration generated by switching the four-way valve at the start of defrosting can be dispersed for each outdoor unit within a predetermined time. Noise and piping vibration at the start of defrosting of the outdoor unit will not be concentrated and increased at once.

Further, since the defrosting operation of all the outdoor units is performed collectively, it is not necessary to frequently defrost each outdoor unit.

Furthermore, when the defrosting operation is started, the outdoor units sequentially start the defrosting operation in the order of priorities set in the control device in advance. If the priority order is set in advance in the control device so that the defrosting operation starts, the defrosting of the outdoor unit, which has a large amount of frost and takes a long time to defrost, can be completed earlier, so a complicated computing device is used. The overall defrosting time can be further shortened in a control device that does not have the same.

In the present embodiment, the defrosting method is the reverse cycle method in which the four-way valve 23 is switched, but defrosting by hot gas bypass may be used. When defrosting the hot gas bypass, the indoor unit 14,
The effect that it is not necessary to stop the blower 28 of 15 is acquired.

(Second Embodiment) FIG. 3 is a flowchart showing a defrosting method for an air conditioner according to a second embodiment of the present invention.

The operation of the heating operation and the defrosting start condition are the same as those of the first embodiment, and the description thereof will be omitted here, and the operation of the defrosting operation will be described with reference to FIG.

First, in step 1, heating operation is performed in the cycle described above. Next, if at least one outdoor unit satisfies the defrosting start condition, the temperature detected by the temperature detector 26 becomes equal to or lower than a predetermined temperature (for example, −10 ° C.) in step 2, step 3
Go to step 1 if there is not one.

In step 3, the temperature detector 26 gives a higher priority to one having a lower detected temperature. This utilizes the characteristic that the temperature detected by the temperature detector 26 decreases as the amount of frost increases. Here, the detected temperature of the outdoor unit 12 is -10.
When the outdoor unit 13 is -8 ° C at ℃, the priority is the outdoor unit 1
2 is number 1 and outdoor unit 13 is number 2.

In step 4, the defrosting operation is sequentially started at predetermined time intervals from the outdoor unit having a high priority, that is, the outdoor unit having a large amount of frost. Here, for example, if the predetermined time is set to 5 seconds, the outdoor unit 12 first starts defrosting. The outdoor unit 12 switches the four-way valve 23 to set a cooling cycle. As a result, the refrigerant discharged from the compressor radiates heat in the outdoor heat exchanger, so defrosting can be performed. Next, at intervals of 5 seconds, the outdoor unit 13 similarly switches the four-way valve 23 to start defrosting.
When the four-way valve 23 is switched, the refrigerant noise and the pipe vibration are generated for 2 to 3 seconds after the switching because the flow of the refrigerant is changed, but the four-way valve switching between the outdoor unit 12 and the outdoor unit 13 is five.
Due to the time interval of seconds, this refrigerant noise and vibration do not overlap. Further, the blowers 28 of the indoor units 14 and 15 are stopped when the first outdoor unit starts defrosting in order to prevent blowout of cold air during the defrosting operation.

Next, in step 5, the outdoor unit that satisfies the defrosting termination condition switches the four-way valve 23 to terminate the defrosting and starts the heating operation. Here, the defrosting is ended when the temperature detected by the temperature detector 26 becomes equal to or higher than a predetermined temperature (for example, 10 ° C.).

In step 6, it is judged whether or not all the outdoor units have finished defrosting. If not, the process returns to step 5,
If completed, the process returns to step 1 to restart the heating operation, and the blowers 28 of the indoor units 14 and 15 also restart the blowing.

As described above, according to the defrosting method for the air conditioner according to the second embodiment, if there is one of the plurality of outdoor units 12 and 13 that satisfies the defrosting condition, all the outdoor units are Since the defrosting operation is sequentially started at a predetermined time interval, noise and pipe vibration generated by switching the four-way valve at the start of defrosting can be dispersed for each outdoor unit within a predetermined time, Noise and piping vibration at the start of defrosting of the outdoor unit will not be concentrated and increased at once.

Further, since the defrosting operation of all the outdoor units is collectively performed, it is not necessary to frequently defrost each outdoor unit.

Further, the temperature of the heat exchangers of the outdoor units 12 and 13 is detected by the temperature detector 26, and the defrosting is sequentially started from the outdoor unit having the lower temperature. Since the defrosting of such an outdoor unit can be completed earlier, the entire defrosting time can be further shortened.

[0045]

As described above, according to the present invention, in a defrosting method for an air conditioner including a plurality of outdoor units, if there is a defrosting condition among the plurality of outdoor units,
Since all outdoor units are characterized by starting defrosting operation sequentially at a predetermined time interval, noise and pipe vibration generated by switching the four-way valve at the start of defrosting and the operation of the hot gas bypass valve Since it can be distributed to each outdoor unit in a predetermined time, noise and piping vibration at the start of defrosting of multiple outdoor units do not concentrate and increase at the same time, and the defrosting operation of all outdoor units can be summarized. Therefore, it is not necessary to frequently defrost each outdoor unit.

Further, since the defrosting operation is sequentially started in the order of the priorities set in the control device at the start of the defrosting operation, the outdoor unit which takes time to defrost is removed first. If the priority order is set in advance in the control device so as to start the frost operation, the defrosting of the outdoor unit, which has a large amount of frost formation and takes a long time to defrost, can be completed earlier, so a control device that does not use a complicated arithmetic unit In, it is possible to further shorten the entire defrosting time.

Further, by detecting the temperatures of the heat exchangers of a plurality of outdoor units at the time of starting the defrosting operation and sequentially starting the defrosting from the outdoor units having a low temperature, a large amount of frost is formed and it takes time to defrost. Since the defrosting of the outdoor unit that requires a lot of time can be completed earlier, the entire defrosting time can be further shortened.

[Brief description of drawings]

FIG. 1 is a flowchart of a first embodiment of a defrosting method for an air conditioner according to the present invention.

FIG. 2 is a refrigerant circuit diagram of Embodiment 1 of the air conditioner according to the present invention.

FIG. 3 is a flowchart of Embodiment 2 of a defrosting method for an air conditioner according to the present invention.

FIG. 4 is a flowchart of a conventional defrosting method for an air conditioner including a plurality of outdoor units.

[Explanation of symbols]

 11 Air Conditioner 12 Outdoor Unit 13 Outdoor Unit 26 Temperature Detector 30 Control Device

Claims (3)

[Claims] 1. In a defrosting method for an air conditioner comprising a plurality of outdoor units, if one of the plurality of outdoor units that satisfies the defrosting condition is satisfied, a predetermined time interval is set for all the outdoor units. A defrosting method for an air conditioner, which comprises sequentially starting a defrosting operation. 2. The defrosting method for an air conditioner according to claim 1, wherein the defrosting operation is sequentially started in the order of priorities set in the control device at the start of the defrosting operation. 3. The air conditioner according to claim 1, wherein the temperatures of the heat exchangers of the plurality of outdoor units are detected at the time of starting the defrosting operation, and the defrosting operation is sequentially started from the outdoor unit having the lower temperature. How to defrost machine.