JPH0526531A - Air-conditioner - Google Patents

Abstract

PURPOSE:To provide an air-conditioner which shortens a time required for defrosting operation. CONSTITUTION:During defrosting operation, flow rate regulating valves 13 and 23 located in respective pipes on the gas side between indoor heat- exchangers 12 and 22 and a four-way valve 2 are brought into a full closed state or a microopening state. Electronic expansion valves 11 and 21 in respective pipes on the liquid side between an outdoor heat-exchanger 3 and the indoor heat-exchangers 12 and 22 are brought into a full opening state or a set opening state, and a part of a refrigerant delivered from a compressor 1 is caused to flow to the outdoor heat-exchanger 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-type air conditioner including an outdoor unit and a plurality of indoor units.

[0002]

2. Description of the Related Art Generally, in a multi-type air conditioner including an outdoor unit and a plurality of indoor units, the capacity of the compressor is controlled according to the total required capacity of each indoor unit.

Furthermore, a flow rate adjusting valve and an expansion valve are provided in the liquid pipes connected to the respective indoor units, and the opening of each flow rate adjusting valve is individually controlled according to the required capacity of the corresponding indoor unit. Further, during cooling operation, the degree of refrigerant superheat in each indoor unit is controlled to be constant by adjusting the opening degree of each expansion valve based on its own temperature sensing. If the outside air temperature is low during the heating operation, frost easily forms on the outdoor heat exchanger. Therefore, the defrosting operation is performed regularly or as needed.

For example, in an air conditioner of the type having a refrigeration cycle as shown in FIG. 1, in the defrosting operation, the two-way valve 6 is operated when the temperature detected by the indoor heat exchanger 33 (= evaporator temperature) falls below a set value. Is opened and a part of the high temperature refrigerant discharged from the compressor 1 is injected into the outdoor heat exchanger 3.

[0005]

However, during the defrosting operation, the flow rate adjusting valves 13 and 23 were fully opened, and the electronic expansion valves 11 and 21 were set to the predetermined openings, so that the refrigerant was used as the indoor heat exchanger 12, However, there is a problem that the defrosting time becomes longer due to insufficient defrosting ability. The present invention has been made in view of the above points, and an object thereof is to provide an air conditioner that can shorten the time for defrosting operation.

[0006]

The present invention provides an air conditioner comprising a compressor, a four-way valve, an outdoor unit having an outdoor heat exchanger, and a plurality of indoor units each having an indoor heat exchanger. Four-way valve, outdoor heat exchanger,
A heat pump type refrigeration cycle in which a parallel circuit of each indoor heat exchanger is connected, an electronic expansion valve provided in each liquid side pipe between the outdoor heat exchanger and each indoor heat exchanger, each indoor heat exchanger and four-way Flow control valve provided on each gas side pipe between the valve and the four-way valve for each refrigerant discharged from the compressor, each flow control valve, each indoor heat exchanger, each electronic expansion valve, outdoor heat exchanger A means for performing a sink heating operation through the
Means for controlling the opening of each flow rate adjusting valve according to the total required capacity of each indoor unit, and performing defrosting operation by flowing a part of the refrigerant discharged from the compressor to the outdoor heat exchanger during heating operation The air conditioner is provided with a means for performing the defrosting operation, and a means for fully closing or slightly opening the flow rate adjusting valve and fully opening or setting the electronic expansion valve during the defrosting operation.

[0007]

[Operation] During the defrosting operation, the flow rate adjusting valves provided in communication between the gas pipes between the indoor heat exchangers and the four-way valve are fully closed or have a small opening, and the outdoor heat exchangers The electronic expansion valves provided in the liquid pipes between the indoor heat exchanger and the indoor heat exchanger are fully opened or set to have a set opening degree so that the high-temperature refrigerant discharged from the compressor flows to the outdoor heat exchanger.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, A is an outdoor unit, B
1 and B2 are indoor units on which the next refrigeration cycle is constructed.

An outdoor heat exchanger 3 is connected to the discharge port of the compressor 1 via a four-way valve 2, and the outdoor heat exchanger 3 is connected to the liquid side main pipe W.
Connect. The liquid side main pipe W is branched into liquid side branch pipes W1 and W2, and the liquid side branch pipes W1 and W2 are connected to the indoor heat exchanger 1.
Connect to 2, 22. Then, the liquid side branch pipes W1 and W2 are provided with electronic expansion valves (pulse motor valves; PMV) 11 and 21 which are pressure reducing means.

A gas side branch pipe G1 is attached to the indoor heat exchangers 12 and 22.
, G2 are connected to the gas side branch pipes G1, G2 of the electric flow rate adjusting valve (pulse motor valve; PMV) 13, 23.
To provide. The gas side branch pipes G1 and G2 are concentrated on the gas side main pipe G, and the gas side main pipe G is connected to the suction port of the compressor 1 via the four-way valve 2 and the accumulator 4.

Connect one end of the bypass 5 to the liquid side main pipe W,
The other end of the bypass 5 is connected to the pipe between the discharge port of the compressor 1 and the four-way valve 2. Then, the two-way valve 6 is provided in the bypass 5. The bypass 5 and the two-way valve 6 are for defrosting the outdoor heat exchanger 3.

Liquid side branch pipe W immediately after branching from the liquid side main pipe W
One end of the bypass 14 is connected to 1, and the other end of the bypass 14 is connected to the gas side branch pipe G1 between the indoor heat exchanger 12 and the flow rate adjusting valve 13. Then, the capillary tube 15 is provided in the bypass 14.

Liquid side branch pipe W immediately after branching from the liquid side main pipe W
2 is connected to one end of a bypass 24, and the other end of the bypass 24 is connected to a gas side branch pipe G2 between the indoor heat exchanger 22 and the flow rate adjusting valve 23. Then, the capillary tube 25 is provided in the bypass 24. The outdoor fan 7 is provided near the outdoor heat exchanger 3, and the indoor fans 16 and 26 are provided near the indoor heat exchangers 12 and 22, respectively. A refrigerant temperature sensor 31 for detecting the temperature of the refrigerant discharged from the compressor 1 is attached to the high pressure side pipe between the discharge port of the compressor 1 and the four-way valve 2. A refrigerant temperature sensor 32 for detecting the temperature of the refrigerant sucked into the compressor 1 is attached to the low-pressure side pipe between the accumulator 4 and the suction port of the compressor 1. The heat exchanger temperature sensor 33 is attached to the outdoor heat exchanger 3. A refrigerant temperature sensor 34 for detecting the temperature of the refrigerant flowing into the indoor heat exchanger 3 is attached to the liquid side main pipe W.
A refrigerant temperature sensor 35 for detecting a refrigerant saturation temperature corresponding to a low pressure when the indoor unit B1 is cooled is attached to the other end of the bypass 14. A refrigerant temperature sensor 36 for detecting the refrigerant saturation temperature corresponding to the low pressure when the indoor unit B2 is cooled is attached to the other end of the bypass 24. Gas side pipe G1
In the indoor heat exchanger 1 than in the connection part of the bypass 14
A refrigerant temperature sensor 37 that detects the outlet temperature of the indoor heat exchanger 12 is attached to the second side. In the gas side pipe G2,
A refrigerant temperature sensor 3 for detecting the outlet temperature of the indoor heat exchanger 22 on the indoor heat exchanger 22 side of the connection portion of the bypass 24.
Attach 8. The control circuit is shown in FIG. A refrigerant pressure sensor 39 for detecting the discharged refrigerant pressure is attached to the high pressure side pipe between the discharge port of the compressor 1 and the four-way valve 2. Reference numeral 40 is a commercial AC power source, and the outdoor control unit 50 of the outdoor unit A is connected to the power source 40. The outdoor control unit 50 includes a microcomputer and its peripheral circuits, and controls the entire outdoor unit A.

The outdoor control unit 50 is provided with an electronic expansion valve 11,
Flow rate adjusting valve 13, electronic expansion valve 21, flow rate adjusting valve 23, two-way valve 6, four-way valve 2, outdoor fan motor 7M, refrigerant temperature sensor 31, 32, 34, 35, 36, 37, 38, heat exchanger temperature The sensor 33, the refrigerant pressure sensor 39, and the inverter circuit 51 are connected.

The inverter circuit 51 is a commercial AC power source 40.
Is rectified, converted into a voltage of a predetermined frequency (and level) according to a command from the outdoor control unit 50, and output. This output is supplied to the compressor motor 1M as drive power. The indoor unit B1 includes an indoor controller 60. The indoor control unit 60 is composed of a microcomputer and its peripheral circuits, and controls the entire indoor unit B1. This indoor control unit 6
An indoor temperature sensor 61, a remote control type operation unit (hereinafter abbreviated as a remote controller) 62, and an indoor fan motor 16M are connected to 0. The indoor unit B2 includes an indoor controller 60. The indoor control section 60 is composed of a microcomputer and its peripheral circuits and controls the overall indoor unit B2. The indoor control unit 60 includes an indoor temperature sensor 61, a remote controller 62,
And the indoor fan motor 26M is connected. Then, the indoor control units 60, 60 are connected to the outdoor control unit 50 by the power supply line ACL and the serial signal line SL, respectively. The indoor control units 60, 60 include the following functional means. (1) A means for sending an operation mode command or set room temperature data by operating the remote controller 62 to the outdoor control unit 50 by a serial signal synchronized with the power supply voltage.

(2) The difference between the detected temperature of the room temperature sensor 61 and the set room temperature of the remote controller 62 (that is, the air conditioning load) is detected, and this is used as the required capacity and replaced with the frequency command code S to synchronize the power supply voltage. A means for sending a serial signal to the outdoor control unit 50. The outdoor control unit 50 includes the following functional means.

(1) Based on the cooling operation mode command from the indoor units B1 and B2, the refrigerant discharged from the compressor 1 is supplied with the four-way valve 2, the outdoor heat exchanger 3, the electronic expansion valves 11 and 21,
Means for performing cooling operation by flowing through the indoor heat exchangers 12, 22, the flow rate adjusting valves 13, 23, the four-way valve 2, and the accumulator 4. (2) A means for controlling the capacity of the compressor 1 (= the output frequency F of the inverter circuit 51) during the cooling operation in accordance with the sum of the required capacities of the indoor units B1 and B2. (3) A means for controlling the opening of the flow rate adjusting valves 13 and 23 according to the required capacity of the indoor units B1 and B2 during the cooling operation.

(4) Indoor heat exchangers 12 and 1 during cooling operation
A means for obtaining the degree of refrigerant superheat (= difference between the temperature detected by the refrigerant temperature sensors 36, 36 and the temperature detected by the refrigerant temperature sensors 37, 38) in 3. (5) Means for controlling the openings of the electronic expansion valves 11 and 21 so that the detected refrigerant superheats have constant values.

(6) During the cooling operation, the liquid-side electronic expansion valve corresponding to the indoor unit that is stopped (including interruption based on indoor temperature control) is fully closed, and the gas-side flow rate adjustment valve is opened to a predetermined opening. A means for opening up to (for example, 250 pulses). The purpose of this means is to collect the refrigerant and prevent freezing and dew condensation.

(7) Based on the heating operation mode command from the indoor units B1 and B2, the refrigerant discharged from the compressor 1 is supplied with the four-way valve 2, the flow rate adjusting valves 13 and 23, and the indoor heat exchanger 1.
2, 22, electronic expansion valves 11, 21, flow through the outdoor heat exchanger 3, the four-way valve 2, and the accumulator 4 to perform heating operation. (8) A means for controlling the capacity of the compressor 1 (= output frequency F of the inverter circuit 51) during the heating operation in accordance with the sum of the required capacities of the indoor units B1 and B2. (9) Means for controlling the opening of the flow rate adjusting valves 13 and 23 according to the required capacity of the indoor units B1 and B2 during heating operation. (10) During heating operation, the degree of refrigerant superheat in the outdoor heat exchanger 3 (= the temperature detected by the refrigerant temperature sensor 34 and the refrigerant temperature sensor 3)
(Difference from the detected temperature of 2). (11) A means for simultaneously controlling the opening amounts of the electronic expansion valves 11 and 21 by the same amount so that the detected refrigerant superheats have constant values.

(12) During the heating operation, when the detected pressure Pd of the pressure sensor 39 becomes equal to or higher than the set value Pds, the opening degree of the liquid side electronic expansion valve and the gas side flow rate adjusting valve corresponding to the stopped indoor unit is changed. Means to open each to a predetermined opening. The purpose of this means is to increase the total capacity of the indoor heat exchanger to lower the condensation temperature and suppress the rise of the high pressure side pressure.

(13) During the heating operation, when the temperature detected by the heat exchanger temperature sensor 33 (= evaporator temperature) becomes less than the set value, the two-way valve 6 is opened and the flow rate adjusting valves 13, 23 are fully closed (or A means for executing the defrosting operation by causing the high temperature refrigerant to flow through the outdoor heat exchanger 3 with the electronic opening valves 11 and 21 fully opened (or the set opening degree). Next, the operation will be described. First, it is assumed that the cooling operation mode and the desired indoor temperature are set by the remote controllers 62 of the indoor units B1 and B2, respectively, and the operation start operation is performed.

In this case, the compressor 1 is started, and the refrigerant discharged from the compressor 1 is transferred to the four-way valve 2 as shown by the solid line arrow in FIG.
Flow through the outdoor heat exchanger 3, the electronic expansion valves 11 and 21, the indoor heat exchangers 12 and 22, the flow rate adjusting valves 13 and 23, the four-way valve 2 and the accumulator 4 to cool the indoor units B1 and B2. Start driving.

Then, the capacity of the compressor 1 (= output frequency F of the inverter circuit 51) is summed up of the required capacities (corresponding to the difference between the set indoor temperature and the detected temperature of the indoor temperature sensor 61) of the indoor units B1 and B2. Control according to. At the same time, the opening degree of the flow rate adjusting valve 13 is controlled according to the required capacity of the indoor unit B1, and the opening degree of the flow rate adjusting valve 23 is controlled according to the required capacity of the indoor unit B2.

Further, the difference between the temperature detected by the refrigerant temperature sensor 35 (= refrigerant saturation temperature) and the temperature detected by the refrigerant temperature sensor 37 is detected as the degree of refrigerant superheat in the indoor heat exchanger 12,
The electronic expansion valve 11 so that the detected refrigerant superheat degree becomes a constant value
Control the opening. At the same time, the difference between the temperature detected by the refrigerant temperature sensor 36 (= refrigerant saturation temperature) and the temperature detected by the refrigerant temperature sensor 38 is detected as the degree of refrigerant superheat in the indoor heat exchanger 22, and the detected degree of refrigerant superheat has a constant value. The opening degree of the electronic expansion valve 21 is controlled so that This ensures stable operation of the refrigeration cycle.

Next, it is assumed that the cooling operation mode and the desired indoor temperature are set by the remote controller 62 of the indoor unit B1 and the operation start operation is performed. The indoor unit B
No. 2 will be stopped.

In this case, the compressor 1 is started, and the refrigerant discharged from the compressor 1 is transferred to the four-way valve 2 as shown by the solid line arrow in FIG.
The outdoor heat exchanger 3, the electronic expansion valve 11, the indoor heat exchanger 12,
Flow through the flow rate control valve 13, the four-way valve 2, and the accumulator 4 to start the independent cooling operation of the indoor unit B1.

Then, the capacity of the compressor 1 (= the output frequency F of the inverter circuit 51) is controlled according to the required capacity of the indoor unit B1 (corresponding to the difference between the set room temperature and the temperature detected by the room temperature sensor 61). .. At the same time, the opening degree of the flow rate adjusting valve 13 corresponding to the indoor unit B1 is controlled according to the required capacity of the indoor unit B1.

Further, the difference between the temperature detected by the refrigerant temperature sensor 35 (= refrigerant saturation temperature) and the temperature detected by the refrigerant temperature sensor 37 is detected as the degree of refrigerant superheat in the indoor heat exchanger 12,
The electronic expansion valve 11 so that the detected refrigerant superheat degree becomes a constant value
Control the opening. This ensures stable operation of the refrigeration cycle.

Further, the electronic expansion valve 21 corresponding to the stopped indoor unit B2 is fully closed, and the flow rate adjusting valve 23 is opened to a predetermined opening (equivalent to 250 pulses). By this opening, the refrigerant in the indoor heat exchanger 22 is recovered and the indoor heat exchanger 22 is prevented from freezing and dew. On the other hand, it is assumed that the heating operation mode and the desired indoor temperature are set by the remote controllers 62 of the indoor units B1 and B2, respectively, and the operation start operation is performed.

In this case, the compressor 1 is started, and the refrigerant discharged from the compressor 1 is transferred to the four-way valve 2 as shown by the broken line arrow in FIG.
Flow through the flow rate adjusting valves 13 and 23, the indoor heat exchangers 12 and 22, the electronic expansion valves 11 and 21, the outdoor heat exchanger 3, the four-way valve 2 and the accumulator 4 to heat the indoor units B1 and B2. Start driving.

Then, the capacity of the compressor 1 (= the output frequency F of the inverter circuit 51) is controlled in accordance with the total required capacity of the indoor units B1 and B2. At the same time, the flow control valve 1
3 is controlled according to the total required capacity of the indoor unit B1, and the opening of the flow rate adjusting valve 23 is controlled to the indoor unit B2.
Control according to the total required capacity of.

Further, the degree of refrigerant superheat in the outdoor heat exchanger 3 (= the temperature detected by the refrigerant temperature sensor 34 and the refrigerant temperature sensor 3).
The difference between the detected temperature and the detected temperature of 2) is detected, and the opening degrees of the electronic expansion valves 11 and 21 are simultaneously controlled by the same amount so that the detected refrigerant superheat degree becomes a constant value. This ensures stable operation of the refrigeration cycle.

Next, it is assumed that the heating operation mode and the desired room temperature are set by the remote controller 62 of the indoor unit B1 and the operation start operation is performed. The indoor unit B
No. 2 will be stopped.

In this case, the compressor 1 is started and the refrigerant discharged from the compressor 1 is supplied with the four-way valve 2 as shown by the broken line arrow in FIG.
Flow rate adjusting valve 13, indoor heat exchanger 12, electronic expansion valve 11,
It flows through the outdoor heat exchanger 3, the four-way valve 2, and the accumulator 4 to start the independent heating operation of the indoor unit B1.

Then, the capacity of the compressor 1 (= the output frequency F of the inverter circuit 51) is controlled according to the required capacity of the indoor unit B1. At the same time, the opening degree of the flow rate adjusting valve 13 corresponding to the indoor unit B1 is controlled according to the required capacity of the indoor unit B1.

Further, the degree of refrigerant superheat in the outdoor heat exchanger 3 (= the temperature detected by the refrigerant temperature sensor 34 and the refrigerant temperature sensor 3).
The difference between the detected temperature and the detected temperature of 2) is detected, and the opening degree of the electronic expansion valve 11 is controlled so that the detected refrigerant superheat degree becomes a constant value. This ensures stable operation of the refrigeration cycle.

When the pressure Pd detected by the pressure sensor 39 becomes equal to or higher than the set value Pds, the opening degree of the electronic expansion valve 21 and the flow rate adjusting valve 23 corresponding to the stopped indoor unit B2 is opened to a predetermined opening degree. Electronic expansion valve 21 and flow rate adjustment valve 2
When 3 opens to a predetermined opening, the refrigerant flows into the indoor heat exchanger 22 and the high-pressure side pressure decreases.

By the way, when the temperature detected by the heat exchanger temperature sensor 33 (= evaporator temperature) falls below the set value while the above-described heating operation mode is being executed, the two-way valve as shown in FIG. 6 is opened, the flow rate adjusting valves 13 and 23 are fully closed (or a small opening degree), the electronic expansion valves 11 and 21 are fully opened (or a set opening degree), and the high temperature refrigerant is flown into the outdoor heat exchanger 3 to perform the defrosting operation. To execute.

Thus, during the defrosting operation, the flow rate adjusting valve 13,
Since 23 is fully closed (or has a very small opening), the refrigerant hardly flows into the indoor heat exchangers 12 and 22, and the flow rate of the refrigerant flowing into the outdoor heat exchanger 3 via the bypass 5 increases.

Further, since the electronic expansion valves 11 and 21 are fully opened (or set opening degree), the refrigerant accumulated in the indoor heat exchangers 12 and 22 during the heating operation before the start of the defrosting operation is exchanged with the outdoor heat. The amount of the refrigerant that can be collected in the outdoor heat exchanger 3 can be further increased.

Thus, during the defrosting operation, the indoor heat exchanger 1
Since it is possible to increase the amount of the refrigerant flowing to the outdoor heat exchanger 3 without causing the refrigerant to stay in Nos. 2 and 22, the defrosting time can be shortened.

[0043]

As described in detail above, according to the present invention, it is possible to provide an air conditioner capable of shortening the time for defrosting operation.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a refrigeration cycle according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a control circuit of the same embodiment.

FIG. 3 is a flowchart for explaining the operation of the same embodiment.

[Explanation of symbols]

A ... Outdoor unit, B1, B2 ... Indoor unit, 1 ... Compressor, 3 ... Outdoor heat exchanger, 11, 12 ... Electronic expansion valve, 1
2, 22 ... Indoor heat exchanger, 13, 23 ... Flow rate adjusting valve, 5
0 ... outdoor control unit, 51 ... inverter circuit, 60 ... indoor control unit.

Claims (1)

Claim: What is claimed is: 1. An air conditioner comprising a compressor, a four-way valve, an outdoor unit having an outdoor heat exchanger, and a plurality of indoor units each having an indoor heat exchanger. A heat pump type refrigeration cycle in which a four-way valve, an outdoor heat exchanger, and a parallel circuit of each indoor heat exchanger are connected, and an electronic expansion valve provided on each liquid side pipe between the outdoor heat exchanger and each indoor heat exchanger. And flow control valves provided on the gas side pipes between the indoor heat exchangers and the four-way valves, four-way valves for refrigerant discharged from the compressor, each flow control valve, each indoor heat exchanger. , Means for performing a heating operation by flowing through each of the electronic expansion valves and the outdoor heat exchanger, and means for controlling the opening degree of each of the flow rate adjusting valves according to the total required capacity of each indoor unit during the heating operation And the discharge of the compressor during heating operation Means for performing a defrosting operation by flowing a part of the medium into the outdoor heat exchanger, and during this defrosting operation, the flow rate adjusting valve is fully closed or a small opening, respectively, and the electronic expansion valve is fully opened or set open, respectively. An air conditioner characterized by comprising: