JPH0719568A - Air conditioner - Google Patents

Abstract

PURPOSE:To improve a heating capacity in defrosting operation. CONSTITUTION:An air conditioner 1 capable of carrying out a hot gas defrosting operation is operated such that during a hot gas defrosting operation, an indoor blower 50 is operated in response to a temperature of an indoor heat exchanger 10 and/or a refrigerant pressure. In the case that at least one of outdoor devices is recovered to a heating operation during defrosting operation of a plurality of outdoor devices 7 and 8, an indoor blower 10 stored in the indoor devices 5 and 6 is operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner capable of performing hot gas defrosting.

[0002]

2. Description of the Related Art Generally, in an air conditioner having a heat pump type refrigeration cycle, frost may form on the outdoor heat exchanger during heating operation. Such frost reduces the operating efficiency of the air conditioner, so defrosting is performed as necessary. As such a defrosting method, conventionally, a so-called reverse cycle method of reversing a four-way valve to switch from a heating cycle to a cooling cycle to defrost has been general, but according to this method, an indoor heat exchanger is cooled. It becomes a state (evaporator). Therefore, since the operation of the indoor blower is stopped, the heating operation is temporarily interrupted and comfortable heating cannot be obtained.

On the other hand, the refrigerant discharged from the compressor is directly guided to the outdoor heat exchanger and also to the indoor heat exchanger so that the indoor heat exchanger acts as a condenser. Is known. As an example, the applicant has proposed Japanese Patent Application No. 5-103002. According to this defrosting method, since the indoor heat exchanger functions as a condenser even during defrosting, a feeling of cool air is less likely to be given as compared with the above-described reverse cycle defrosting method.

[0004]

However, in this hot gas defrosting, since the heating capacity is lowered, the temperature drop of the indoor heat exchanger is inevitable. Here, in the multi-type air conditioner of Japanese Patent Application No. 5-103002 previously proposed by the applicant, there is a defrosting operation state in which the condensation capacity is larger than the evaporation capacity, and in this case the indoor heat It was found that the temperature drop of the exchanger was small.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an air conditioner which suppresses a decrease in indoor heating capacity during hot gas defrosting or when at least one of a plurality of outdoor units returns to a heating state. is there.

[0006]

To achieve this object, the present invention relates to an air conditioner capable of performing hot gas defrosting, in which the indoor blower is set to the temperature of the indoor heat exchanger and / or The operation is performed according to the refrigerant pressure. Further, when at least one outdoor unit returns to the heating operation during the defrosting operation of the plurality of outdoor units, the indoor blower built in the indoor unit is operated.

[0007]

When the temperature of the indoor heat exchanger is high during hot gas defrosting, the indoor blower is operated and the room is heated. Further, when at least one of the plurality of outdoor units is switched from defrosting to heating, the indoor blower is operated.

[0008]

Embodiments of the air conditioner according to the present invention will now be described in detail with reference to the accompanying drawings. In FIG.
The air conditioner 1 is composed of a plurality of outdoor units 7 and 8 and a plurality of indoor units 5 and 6, and in these outdoor units 7 and 8, inter-unit piping including a gas pipe 2 and a liquid pipe 3 is provided. 4 are connected, and indoor units 5 and 6 are connected in parallel to the inter-unit pipe 4.

Each of the indoor units 5 and 6 has an indoor electric expansion valve (pressure reducer) 9, an indoor heat exchanger 10, an indoor heat exchanger 10 and indoor air for exchanging heat between the indoor air and the indoor air. The fan 50 and an indoor controller 51 that controls the number of revolutions of the fan 50 are provided. Outdoor unit 7,8
Is a compressor 12, 13, an oil separator 14, and a four-way valve 15
, Outdoor heat exchanger 16, outdoor electric expansion valve (pressure reducer)
17 and 17.

The outdoor heat exchanger 16 and the outdoor electric expansion valve 17
A hot gas valve 18 is provided between the hot air valve 18 and the hot gas bypass pipe 52 to directly introduce a part of the refrigerant discharged by the compressors 12 and 13 into the outdoor heat exchanger 16 during the defrosting operation. It is supposed to do. Return pipes 19 are connected to the oil separators 14 of the outdoor units 7 and 8, respectively, and the return pipes 19 are connected to a common oil return pipe 20 and the respective compressors 12 and 13.

One compressor 13 is a rated compressor that constantly outputs a constant capacity, and the other compressor 12 is a variable compressor (inverter compressor) whose capacity is variable. The outdoor heat exchanger 16 has an inlet temperature detector 21
a, an intermediate temperature detector 21b, and an outlet temperature detector 21c are arranged, and a detection signal of the detected temperature is sent to the control device 23.
It is designed to be sent to. Further, the control device 23 determines the defrosting start state based on the temperature detection signal, and controls the hot gas valve 18 to open during defrosting.

The controller 23 is also connected to the indoor controller 51 of the indoor units 5 and 6. This indoor controller 5
1 includes a temperature detector 53 arranged in the indoor heat exchanger 10.
The signal from is also input. Control device 2
When the defrost signal is input to the indoor controller 51 from No. 3, the rotation speed of the indoor blower 50 is controlled as shown in FIG. When a heating signal is input to the indoor controller 51, the rotation speed of the indoor blower 50 is controlled as shown in FIG.

Next, the operation of this embodiment will be described.
According to the air conditioner 1 of the present embodiment, during heating operation,
The four-way valve 15 in FIG. 1 is in a solid line state, and as shown by the solid line, in each of the outdoor units 7 and 8, the refrigerant flows into the gas pipe 2 via the compressors 12 and 13, the oil separator 14, and the four-way valve 15. It is introduced and passes through the indoor heat exchanger 10 of the outdoor unit 5, and through the indoor electric expansion valve 9, the liquid pipe 3, the outdoor electric expansion valve 17, the outdoor heat exchanger 16, the four-way valve 15, and the compressor 1.
Returned to 2, 13.

The compressor 13 is a rated compressor and always operates with a constant capacity, but since it is a variable compressor of the compressor 12, it operates while the capacity varies according to the required load. Normally, the vehicle is operating in a condition lower than the full condition. During the cooling cycle, the four-way valve is in a broken line state, and conversely, the refrigerant is circulated.

When the temperature of the outdoor heat exchanger 16 decreases during the heating operation and frost forms, the efficiency of the outdoor heat exchanger 16 decreases, so defrosting is necessary. That is, when the temperature detector 21a that detects the temperature of the outdoor heat exchanger 16 detects a predetermined temperature, the controller 23 issues a defrost signal.
In such a case, when either of the temperature detectors 21a of the outdoor units 7 and 8 detects a predetermined temperature, the control device 23 determines that it is in the defrosting state and commands all the outdoor units 7 and 8 to start the defrosting operation. To do.

Here, this defrosting operation control will be mainly described with reference to FIG. When the heating operation switch is input, the heating operation is started in the first step 101. During this heating operation, the rotation speed of the indoor blower 50 is set according to the temperature of the indoor heat exchanger 10. Specifically, as shown in FIG. 3, when the temperature is 30 ° C. or lower, the operation of the blower is stopped, and when the temperature is 30 ° C. to 35 ° C., a slight breeze of 300 rpm is used, and when the temperature is 35 ° C. to 40 ° C. Is 45
With a low wind of 0 rpm, 720 rpm at 40 ° C to 43 ° C
When the temperature is 43 ° C. or higher, it is rotated with a rapid wind of 900 rpm.

During such heating operation, the second step 10
Proceeding to 3, it is determined whether there is at least one outdoor unit to be defrosted among the plurality of outdoor units 7 and 8. In the second step 103, the heat exchanger 1 of each outdoor unit 7, 8 is based on the detection signal from the temperature detector 21a.
The inlet temperature of 6 is measured, and it is determined whether the inlet temperature is lower than a predetermined temperature. If the inlet temperature is lower than the predetermined temperature,
Judge that it should be defrosted. If it is not determined in the second step 103 that defrosting should be performed, the process returns to the first step 101.

If it is determined that defrosting should be performed, the third step 10 is performed on the outdoor units 7, 8 (see FIG. 1) side.
The control based on the fifth to fifth steps 109 is performed, and the control based on the sixth step 111 to the eighth step 115 is performed on the indoor unit 5, 6 (see FIG. 1) side. That is, on the outdoor unit 7, 8 side, first, in the third step 105, the variable compressor 12 is set to full operation. Then, it progresses to 4th step 107, and switches all the outdoor units 7 and 8 to a defrosting operation state, and starts a defrosting operation. Specifically, the hot gas valves 18 of all the outdoor units 7 and 8 are opened, and a part of the refrigerant fully discharged by the compressors 12 and 13 is directly introduced into the outdoor heat exchanger 16. As a result, in the outdoor heat exchanger 16, the high-temperature refrigerant is directly introduced, so that the thermal energy of the refrigerant causes
The outdoor heat exchanger 16 will be defrosted. The compressor 1
The rest of the refrigerant discharged from Nos. 2 and 13 flows into the indoor heat exchanger 16 via the gas pipe 2, so that the indoor heating is continued.

After the fourth step 107, the fifth step 1
Go to 09. In the fifth step 109, defrosting is sequentially ended from the outdoor unit that satisfies the defrosting ending condition, and heating operation is switched to. The determination of the end of defrosting is performed by the temperature detector 21.
The temperatures from a, 21b, and 21c are detected, and it is determined whether or not all the detected temperatures are higher than 6 ° C. If the temperature is higher than 6 ° C, the defrosting operation of the outdoor unit is terminated. When another outdoor unit does not satisfy this condition, the outdoor unit continues the defrosting operation. In this way, since the defrosting is sequentially ended from the outdoor unit that satisfies the defrosting ending condition, the defrosting operation of the outdoor unit with a small amount of frosting ends early, and the high pressure refrigerant pressure during the refrigeration cycle increases. The defrosting time of the remaining outdoor units can be shortened.

On the other hand, during such a defrosting operation, in each of the indoor units 5 and 6, the temperature of the indoor heat exchanger 10 (see FIG. 1) is detected by the detector 53 as shown in the sixth step 111. Then, in the seventh step 113, the operation of the indoor blower 50 is controlled based on the detected temperature as shown in FIG. That is, when the detected temperature is 50 ° C. or lower, the operation of the blower 50 is stopped, when the temperature is 50 ° C. to 55 ° C., a slight breeze of 300 rpm is used, and when the temperature is 55 ° C. to 58 ° C., 450 is blown.
When the temperature is 58 ° C. to 60 ° C., it is a strong wind of 720 rpm, and when it is 60 ° C. or higher, it is a rapid wind of 900 rpm. Then, as shown in the eighth step 115, the temperature of the indoor heat exchanger 10 is constantly detected, and if there is a change in this temperature, the number of revolutions is changed to a value based on the changed value. In this defrosting, all the outdoor units 7 and 8 start the defrosting operation at the same time, but the defrosting operation in each of the outdoor units is sequentially ended from the unit where each unit satisfies the defrosting ending condition. There is. Therefore, at the start of the defrosting operation, a part of the refrigerant discharged from the compressors 12 and 13 flows into the respective outdoor heat exchangers 16, so that the pressure in the gas pipe 2, that is, the high pressure refrigerant pressure (refrigerant temperature) in the refrigeration cycle. Although it does not rise so much, when the defrosted outdoor unit occurs, the above-mentioned high-pressure refrigerant pressure (refrigerant temperature) rises considerably, and with this, the indoor heat exchanger 1
The temperature of 6 also rises. Therefore, the rotation speed of the indoor blower 50 is increased and the heating capacity is increased.

In the ninth step 117, it is judged whether or not all the outdoor units have been defrosted. If all the outdoor units have been defrosted, the tenth step 1
After proceeding to 19 and canceling the full operation of the variable compressor 12,
Returning to the first step 101, the normal heating operation is performed.
When the defrosting operation of all the outdoor units 7 and 8 has not ended, the third step 105 and the sixth step 1
Return to 11.

As described above, according to this embodiment, when at least one of the plurality of outdoor units 7 and 8 is in the defrosting state, the defrosting operation of all the outdoor units 7 and 8 is performed. Start at the same time. Then, by rotating the indoor blower 50 based on the temperature of the indoor heat exchanger 10 during the defrosting operation, the heating capacity is increased as much as possible during the defrosting operation.

In this way, the indoor heat exchanger 10 is operated during the defrosting operation.
The temperature of 50 ° C. or higher is when the capacity of the outdoor units 7 and 8 becomes larger than the capacity of the indoor units 5 and 6 from a different viewpoint. Therefore, when at least one outdoor unit among the plurality of outdoor units 7 and 8 in the defrosting operation returns to the heating operation, the indoor heat exchanger 10 may rise to a temperature at which heating can be sufficiently performed. The operation of the indoor blower may be started at such a time.

The present invention is not limited to the above-described embodiments, but can be variously modified without departing from the gist of the present invention. For example, the outdoor unit may be one, and the air conditioner in which the capacity of the outdoor unit is set to be larger than the capacity of the indoor unit may be used. Furthermore, the temperature of the indoor heat exchanger is detected, and the defrosting operation is started and ended based on the detected value.The detected value is the refrigerant pressure in the indoor heat exchanger, and this pressure and temperature. You may make it judge by a total value.

[0025]

As described above, according to the present invention, in the air conditioner capable of performing hot gas defrosting, the indoor blower is operated according to the temperature of the indoor heat exchanger and / or the refrigerant pressure during the hot gas defrosting. Since this is done, the heating operation can be performed during this defrosting.

Further, when at least one outdoor unit returns to the heating operation during the defrosting operation of the plurality of outdoor units, the indoor blower built in the indoor unit is operated so that the operation returns to the heating operation. The heating operation can be performed using the outdoor unit.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a control state of the indoor blower during defrosting of the air conditioner shown in FIG.

FIG. 3 is an explanatory diagram showing a control state of the indoor blower during heating of the device.

FIG. 4 is a flowchart showing an operation of a defrosting operation of the device.

[Explanation of symbols]

 1 Air conditioner 9,17 Decompressor 10 Indoor heat exchanger 12,13 Compressor 15 Four-way valve 16 Outdoor heat exchanger 50 Indoor blower 52 Hot gas bypass pipe

Claims (2)

[Claims] 1. A compressor, a four-way valve, an outdoor heat exchanger, a pressure reducer, and an indoor heat exchanger are sequentially connected by a refrigerant pipe, and a refrigeration cycle capable of cooling and heating is constructed by switching the four-way valve. In an air conditioner equipped with a hot gas bypass pipe for flowing a part of the refrigerant discharged from the compressor directly to the outdoor heat exchanger during defrosting to melt frost attached to the outdoor heat exchanger by heating, An air conditioner characterized in that an indoor blower for exchanging heat between the indoor heat exchanger and the indoor air at the time of defrosting is operated according to the temperature and / or the refrigerant pressure of the indoor heat exchanger. 2. In an air conditioner in which a plurality of outdoor units and indoor units are connected by a refrigerant pipe, when at least one outdoor unit returns to heating operation during defrosting operation of these plurality of outdoor units, An air conditioner that operates an indoor blower built in the indoor unit.