JPH02171568A - Multi-room air conditioner - Google Patents

Abstract

PURPOSE:To allow the cooling, heating and defrosting operations concurrently by controlling the switching of the four-way valve and the opening and closing of the first bypass valve and the second bypass valve depending on the number of the indoor units in operation for cooling or heating at the time of defrosting. CONSTITUTION:A bypass lie having a first bypass valve BV1 and a defrosting bypass line having a decompressor EXP and a second bypass valve BV2 which connects the suction side of a compressor 2 to an outdoor heat exchanger 4 and the delivery side of the compressor 2 to a four-way valve 3 are formed between the outdoor expansion valve 5 and the header 20. When the outdoor heat exchanger needs to be defrosted during the heating operation, the heating and defrosting mode is selected. The operation is continued as the switching of the four-way valve 3 or the opening and closing or the degree of the opening of the outdoor expansion valve 5, first indoor two-way valves V1a - V1c, second indoor two-way valves V2a - V2c, first indoor expansion valves EV1a - EV1c, second indoor expansion valves EV2a - EV2c, first bypass valve BV1 and second bypass valve BV2 are controlled depending on the operation mode of the outdoor unit.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides refrigeration cycle control and defrosting for simultaneously performing cooling operation and heating operation for each room in a multi-room air conditioner that uses air as a heat source. This invention relates to a heat pump air conditioner equipped with a control.

Prior art A conventional multi-room air conditioner having multiple indoor units has a fourth
As shown in the figure, a compressor 2.
Four-way valve 3. Outdoor heat exchanger4. and an indoor expansion valve 7 in the indoor unit 6 installed in parallel with the outdoor expansion valve 5. In addition, the indoor heat exchangers 8 are connected in parallel and sequentially connected in an annular manner to form a heat pump type refrigeration cycle. The compressor 2 has a variable capacity, and its capacity can be changed by changing the frequency of the supplied power. In addition, cooling operation and heating operation are switched by the four-way valve 3. During cooling operation, the refrigerant flows in the direction of the solid line arrow in the figure to form a cooling cycle, and during heating operation, the refrigerant flows in the direction of the broken line in the figure. A heating cycle is formed. In addition, the outdoor heat exchanger 4
．． An outdoor fan 9 and an indoor fan 10 are installed adjacent to the indoor heat exchanger 8, respectively.

In such a multi-room air conditioner, a plurality of, for example, three, indoor units 6a, 6b+6c can be operated individually, and when only the indoor unit 6a is operated,
In the other indoor units 6b and 6c, the indoor expansion valves 7b and 7c are fully opened, and the indoor blowers 10b and 10c are also stopped. At this time, the capacity of the compressor 2 is controlled by an inverter or the like, and it is possible to operate the compressor 2 at a capacity corresponding to the number of indoor units in operation.

Problems to be Solved by the Invention However, in the conventional example described above, the operation mode of the indoor units 6 is set to the same mode in all three rooms.
For example, even in the winter, two rooms need to be heated and one room needs to be cooled, which has the disadvantage of not being able to meet the need for simultaneous heating and cooling operations.

Therefore, an object of the present invention is to realize simultaneous operation of cooling, heating, and defrosting.

Means for Solving the Problems Technical means of the present invention for solving the above problems include a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor blower.

an outdoor unit consisting of an outdoor expansion valve; an indoor first two-way valve;
A circuit is formed by connecting multiple indoor units in parallel, each consisting of an indoor heat exchanger, an indoor blower, a second indoor two-way valve, a #1 indoor tension valve, and a #2 indoor tension valve. Equipped with a refrigeration cycle, the outdoor unit and each indoor unit are connected by a first two-way valve on the indoor side and a second two-way valve on the indoor side, and the first two-way valve on the indoor side and the indoor heat exchanger are connected. A circuit is formed between the indoor second two-way valve and the indoor heat exchanger by the indoor first expansion valve, the header, and the indoor 21M1 expansion valve, and the outdoor expansion valve and the header. a bypass circuit via a first bypass valve between the Forms a defrosting bypass circuit to cool the indoor unit during defrosting operation.

and a control means for controlling switching of the four-way valve and opening/closing of the first bypass valve and the second bypass valve depending on the number of heating units in operation.

For production The effect of this technical means is as follows.

First, the cooling and heating operation capacities of each indoor unit are compared, and the operation mode of the outdoor unit is determined.

In other words, if (total cooling capacity of the indoor unit) ≧ (total heating capacity of the indoor unit), the outdoor unit will enter cooling operation mode, and if (total cooling capacity of the indoor unit) < (total heating capacity of the indoor unit), the outdoor unit will switch to cooling operation mode. is set to heating operation mode. The respective operation modes of the indoor and outdoor units will be explained below. However, when the four-way valve is ON, the refrigerant flows from the compressor discharge side to the outdoor heat exchanger and from the indoor heat exchanger to the compressor suction side, and when it is OFF, the refrigerant flows from the compressor discharge side to the indoor side. It is assumed that the water flows to the heat exchanger, from the outdoor heat exchanger to the compressor suction side.

Outdoor unit: In case of cooling operation mode> Fully open the outdoor expansion valve, and open the indoor unit No. 1 of the indoor unit in heating mode.
Open the two-way valve, close the second indoor two-way valve, fully open the first indoor expansion valve, fully open the second indoor expansion valve, and close the first indoor two-way valve of the indoor unit in cooling mode. , the second two-way valve on the indoor side,
The first indoor expansion valve is opened to a predetermined degree, the second indoor expansion valve is fully closed, and the first bypass valve of the bypass circuit and the second bypass circuit of the defrosting bypass circuit are closed. At this time, the high-temperature, high-pressure refrigerant sent from the outdoor heat exchanger passes through the indoor first two-way valve of the indoor unit in the heating mode, flows into the indoor heat exchanger, and radiates heat into the room. (Heating operation) After that, the refrigerant passes through the second expansion valve on the indoor side, passes through the header, is depressurized by the first expansion valve on the indoor side of the indoor unit in cooling mode, and becomes liquid or two-phase condensed. After absorbing heat from the indoor heat exchanger (cooling operation), the heat is returned to the outdoor unit via the indoor second two-way valve.

However, when the indoor unit is in the all-room cooling mode, the first bypass valve of the bypass circuit is opened and the high-temperature, high-pressure refrigerant is sent to the header, and the pressure is reduced by the 11th tension valve on the indoor side of the indoor unit and it becomes a liquid or two-phase state. The resulting refrigerant returns to the outdoor unit via the indoor second two-way valve after the indoor heat exchanger absorbs heat from the room (cooling operation).

Outdoor unit: In case of heating operation mode> Open the outdoor expansion valve to the specified degree, close the indoor first two-way valve of the indoor unit in heating mode, open the indoor second two-way valve, and open the indoor first
Fully open the expansion valve, fully close the second indoor expansion valve, open the first indoor two-way valve of the indoor unit in cooling mode, close the second indoor two-way valve, and fully open the first indoor expansion valve. , the indoor second expansion valve is opened to a predetermined degree, and the first bypass valve of the bypass circuit and the second bypass circuit of the defrosting bypass circuit are closed.

At this time, the high-temperature, high-pressure refrigerant sent from the outdoor heat exchanger passes through the indoor second two-way valve of the indoor unit in heating mode, flows into the indoor heat exchanger, and radiates heat into the room (heating operation). After that, it passes through the first Ill tension valve on the indoor side, and then passes through the header.
The refrigerant, which has been depressurized by the second indoor expansion valve of the indoor unit in cooling mode and becomes a liquid or two-phase state, is transferred to the indoor side first two-way valve after cooling operation to absorb heat from the room in the indoor heat exchanger. Return to the outdoor unit via.

Next, during winter heating operation, frost forms on the outdoor heat exchanger,
A case in which defrosting operation is required will be explained.

Outdoor unit: Heating operation & defrosting operation mode / Indoor unit: All heating operation mode> Fully open the outdoor expansion valve, open the indoor unit's first two-way valve on the indoor side, and the second indoor two-way valve, and open the indoor unit's Inner first expansion valve.

The indoor first expansion valve is fully closed, and the first bypass valve of the bypass circuit and the second bypass circuit of the defrosting bypass circuit are closed. At this time, a part of the high-temperature, high-pressure refrigerant discharged from the compressor passes through the indoor first two-way valve of the indoor unit, flows into the indoor heat exchanger, and radiates heat into the room to perform heating operation. However, the indoor fan should have a low air volume. After that, the indoor first two-way valve,
The air returns to the outdoor heat exchanger via the outdoor expansion valve, and the outdoor heat exchanger acts as a condenser to defrost the air. However, the outdoor fan is stopped (at this time, the refrigerant is in a gas-liquid two-phase state). On the other hand, the remainder of the high-temperature, high-pressure refrigerant discharged from the compressor passes through the second bypass circuit of the defrosting bypass circuit and the pressure reducer, becomes high-temperature, low-pressure refrigerant, and flows into the outdoor heat exchanger outlet side, where it is exchanged for outdoor heat exchange. It mixes with the low-dryness refrigerant that exits the container, increases the dryness, and returns to the compressor suction side. That is, it is possible to defrost the outdoor heat exchanger while continuing the heating operation in the indoor unit.

Outdoor unit: Heating operation & defrosting operation mode / Indoor unit: Mixed cooling and heating operation mode> Fully open the outdoor expansion valve, and open the indoor unit 1 in heating mode.
Close the two-way valve, the second indoor two-way valve, fully open the first indoor expansion valve, and the second indoor WI expansion valve, close the first indoor two-way valve of the indoor unit in cooling mode, and close the indoor second WI expansion valve. 2 Open the two-way valve, and set the indoor side No. 1 Ill tension valve to the specified opening.

The second indoor expansion valve is fully opened, the first bypass valve of the bypass circuit is opened, and the second bypass circuit of the defrosting bypass circuit is closed. At this time, the high-temperature refrigerant discharged from the compressor flows into the outdoor heat exchanger, and the outdoor heat exchanger acts as a condenser to defrost. However, the outdoor fan will be stopped. and a first bypass valve of the bypass circuit;
The refrigerant, which has been depressurized through the header and turned into a liquid or two-phase state by the first indoor expansion valve of the indoor unit in cooling mode, is
It flows into the indoor heat exchanger and absorbs heat from the room (cooling operation). Thereafter, it returns to the outdoor unit via the second two-way valve on the indoor side.

As described above, the outdoor unit and each indoor unit are connected by the indoor first two-way valve and the indoor second two-way valve, and the indoor first two-way valve and the indoor heat exchanger are connected to each other. A circuit is formed between the indoor second two-way valve and the indoor heat exchanger by a first indoor expansion valve, a header, and a second indoor expansion valve, and
a bypass circuit via a first bypass valve between the outdoor expansion valve and the header, and a second bypass circuit connecting between the compressor suction side and the outdoor heat exchanger and between the compressor discharge side and the four-way valve; A defrosting bypass circuit is formed via a pressure reducer, and control controls switching of the four-way valve and opening/closing of the first bypass valve and the second bypass valve depending on the number of indoor units in operation for cooling and heating during defrosting operation. By providing the means, it becomes possible to realize simultaneous operation of cooling, heating, and defrosting.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the accompanying drawings, and the same components as those in the conventional art will be denoted by the same reference numerals, and detailed explanation thereof will be omitted.

FIG. 1 is a refrigeration cycle diagram of a heat pump type air conditioner according to an embodiment of the present invention. The heat pump type air conditioner of this embodiment has a compressor 2. Four-way valve 8, outdoor heat exchanger 4
．． Outdoor blower9. Outdoor unit 1 consisting of an outdoor expansion valve 5
and the indoor first two-way valve V 1 + the indoor heat exchanger 8. Indoor blower 10° Indoor second two-way valve V2. Indoor side first expansion valve EVI.

and a refrigeration cycle that connects three indoor units 6 in parallel to form a main circuit, including a second indoor side tension valve EV2,
An outdoor unit 1 and each indoor unit 5a, 6b.

6C is the indoor first two-way valve V 1 a HV l b I
V l c and indoor second two-way valves V2a, V2b, V2
c, and the indoor first two-way valve Via~
Darkness between V1c and indoor heat exchangers 8a to 8C and indoor second
The two-way valves V2a to V2c and the indoor heat exchangers 8a to 8c are connected by a first indoor expansion valve EV1a to EVlc, a header 20° common to each indoor unit, and a second indoor expansion valve EV2a. A circuit connected by EV2c, a bypass circuit between the outdoor expansion valve 5 and the header 20 via the first bypass valve BVI, and a circuit between the compressor 2 suction side and the outdoor heat exchanger 4 and the compressor 2 discharge side. A defrosting bypass circuit is formed via the second bypass valve BV2 connecting between the four-way valves 3 and the pressure reducer EXP.However, the four-way valve 8 is turned ON.
In this case, the refrigerant is transferred from the compressor discharge side to the outdoor heat exchanger 4,
It is assumed that the refrigerant flows from the indoor unit side to the compressor suction side, and when it is OFF, the refrigerant flows from the compressor discharge side to the indoor unit side and from the outdoor heat exchanger to the compressor suction side. As shown in the input/output signal system diagram of the control device in Fig. 2, the signals from the remote controllers 30a, 30b, 30c for each indoor unit are transmitted from the A/D converter, CPU, D/A converter, etc. control device 31
After the necessary calculations, the output signal is sent to the west valve 3.
It is designed to be output to each expansion valve, each two-way valve, each bypass valve, and each blower.

Next, the operation of the configuration of this embodiment will be explained.

FIG. 8 is a flowchart illustrating the control operation of this embodiment. First, the capacity of cooling and heating operations is compared based on the operation mode set with the remote control of each indoor unit, and the operation mode of the outdoor unit is determined. In other words, when (total cooling capacity of the indoor unit) ≧ (total heating capacity M of the indoor unit), the outdoor unit goes into cooling operation mode, and when (total cooling capacity of the indoor unit) < (total heating capacity of the indoor unit), the outdoor unit goes into the cooling operation mode. The machine is set to heating operation mode by the control device 31. Further, during heating operation, if defrosting operation of the outdoor heat exchanger is required, the heating & defrosting operation mode is set. Then, depending on the operation mode of the outdoor unit, the west valve 3 or the outdoor expansion valve 5 is switched. Indoor side first two-way valve Via~V
l c, indoor side second two-way valve ■2a to ■2c, indoor side 18th expansion valve EV1a-E■1c, indoor side second expansion valve E■2
a~EV2Q+ and the first bypass valve BV1. The following operation is performed by controlling the opening/closing or opening degree of the second bypass valve BV2. The table below shows the open/close states of the two-way valve, expansion valve, and bypass valve in each case in this example. This will be explained below with reference to the table below.

Outdoor unit: cooling operation mode> For example, indoor unit 6a is in heating mode, indoor unit 6b+5c
The case where is in cooling mode will be explained.

Fully open the outdoor expansion valve 5, open the indoor first two-way valve Vla of the indoor unit 6a in heating mode, and open the indoor second two-way valve V2 at.
! : Closed, first indoor expansion valve EV1a fully open, second indoor expansion valve
The expansion valve EV2a is fully opened, and the indoor unit 6b is in cooling mode.
Close the indoor first two-way valve ■lb and Vlc of 6c, and close the indoor second two-way valve V2b, V2c1/! : Open, indoor first expansion valve EV1b, EVlc to predetermined opening degree, indoor second expansion valve E
V2b and EV2c are fully closed, and the first bypass valve BVI and second bypass valve BV2 of the bypass circuit are also closed. At this time, the high temperature and high pressure refrigerant sent from the outdoor heat exchanger 4 is transferred to the indoor first two-way valve Vl of the indoor unit 6a in the heating mode.
a, flows into the indoor heat exchanger 8a, and radiates heat indoors (heating operation). After that, it passes through the second indoor expansion valve V2a, and via the header 20, the indoor unit 6b in the cooling mode,
The refrigerant, which has been depressurized by the indoor first expansion valves Vlb and Vlc of 6c and becomes a liquid or two-phase state, is transferred to the indoor heat exchanger 8b.
.

After cooling operation to absorb heat from the room at 8C, the air returns to the four-way valve 3 in the outdoor unit 1 via the second two-way valves V2b and V2c on the indoor side.

However, when the indoor units 6a to 6C are in the all-room cooling mode, the two-way valve BV of the bypass circuit is opened to send high-temperature, high-pressure refrigerant to the header 20, and the indoor temperature 1m high valves Vla to Vlc of the indoor units 6a to 6c are The refrigerant, which has been depressurized and becomes a liquid or two-phase state, is cooled to absorb heat from the room in the indoor heat exchangers 8a to 8c (cooling operation), and then cooled to the indoor second two-way valves V2a to V2c.
It returns to the four-way valve 3 in the outdoor unit 1 via.

For example, when indoor unit 6a is in cooling mode, indoor unit 6b, (3
A case where c is in heating mode will be explained.

The outdoor expansion valve 5 is opened to a predetermined degree, and the indoor unit 6b is in heating mode.
Close the first two-way valves Vlb and VIC on the indoor side of +6c, and open the second two-way valves V2b and V2c on the indoor side.

The indoor first expansion valves EVI b and EVI c are set to predetermined values, the indoor second expansion valves EV2 b and EV2 c are fully closed, the indoor first two-way valve V1a of the indoor unit 6a in cooling mode is opened, and the indoor second Two-way valve V2 a'f: closed, indoor first expansion valve EV1
a is fully closed, the second indoor expansion valve EV2af is set to a predetermined value, and the first bypass valve BVI and second bypass valve BV2 of the bypass circuit are closed. At this time, the high temperature and high pressure refrigerant sent from the outdoor heat exchanger 4 is sent to the indoor unit 6b in the heating mode.
It passes through the indoor second two-way valves V2b and V2c of 6c, flows into the indoor heat exchangers 8b and 8c, and radiates heat into the room (heating operation). After that, the indoor side 1st WIj tension valve v1b, vIcl
g: Through the header 20, the refrigerant that has been depressurized and turned into a liquid or two-phase state by the indoor first expansion valve EV2a of the indoor unit 6a in the cooling mode absorbs heat from the room in the indoor heat exchanger 8a. (cooling operation), the indoor first two-way valve Vl
It returns to the outdoor expansion valve 5 in the outdoor unit 1 via a.

Next, a case will be described in which frost is formed on the outdoor heat exchanger 4 during the winter heating operation and a defrosting operation is required. That is, when the evaporation temperature detected by the evaporation temperature detector 32 installed in the outdoor heat exchanger 4 falls below a predetermined temperature, the control device 31 outputs a signal for defrosting operation, and the outdoor unit (described later) starts heating. Mode & defrost mode 2.

Outdoor unit: Heating operation & defrosting operation mode 1/Indoor unit: All in heating operation mode> For example, a case where indoor units 6a, 5b, (3c) are all in heating mode will be described.

The outdoor expansion valve 5 is fully opened, and the indoor first two-way valves Vla, Vl b, and Vl c of the indoor units 6a+6b and 6C are opened.

Open the second two-way valves V2a, V2b, and V2c on the indoor side.

Indoor side 1st WIj Zhang valve E■1a, E■1b, EVIC.

The indoor second # tension valves EV2a, EV2b, and EV2c are fully closed, and the first bypass valve BV1 and second bypass valve BV2 of the bypass circuit are closed. At this time, a portion of the high-temperature, high-pressure refrigerant discharged from the compressor 2 is supplied to the indoor first two-way valve Vla of the indoor units 6a, 6b, and 6c.

Passing through Vlb and Vlc, the indoor heat exchangers 8a, 8b, 3
c, and radiates heat into the room to perform heating operation. however,
The indoor side blowers 10a, 10b, and 10C have a low air volume.

After that, the indoor side first two-way valve ■1 a + V 1 b
+V 1 c + Returns to the outdoor heat exchanger 4 via the outdoor expansion valve 5, and the outdoor heat exchanger 4 acts as a condenser to defrost. However, the outdoor fan 9 is in a stopped state (at this time, the refrigerant is in a gas-liquid two-phase state). On the other hand, the remainder of the high-temperature, high-pressure refrigerant discharged from the compressor 2 is transferred to the second bypass valve BV2.
The high-temperature, low-pressure refrigerant flows through the pressure reducer EXP to the outlet side of the outdoor heat exchanger, mixes with the low-dryness refrigerant exiting the outdoor heat exchanger 4, increases the dryness, and then flows into the compressor 2. Return to the suction side. That is, it is possible to defrost the outdoor heat exchanger 4 while continuing the heating operation in the indoor units 6a, 6b, and 6C.

<Outdoor unit: heating operation & defrosting operation mode 2/indoor unit: cold,
For heating operation mixed mode> For example, indoor unit 6a is in cooling mode, indoor unit 6b+6c
The case where is in heating mode will be explained.

The outdoor expansion valve 5 is fully opened, and the indoor units 6b and 6c are in heating mode.
Close indoor first two-way valve Vlb, VIC + indoor second two-way valve V2b, V2c, indoor first expansion valve EV1b, EV
IC, indoor second expansion valve EV 2 b J E V 2
c is fully closed, and the indoor side No. 1 of the indoor unit 6a in the cooling mode is fully closed.
The two-way valve Vla is closed, the second indoor two-way valve V2a is opened, the first indoor expansion valve EVla is set to a predetermined opening degree, the second indoor expansion valve EV2a is fully closed, and the second indoor expansion valve EV2a is fully closed. The first bypass valve BV1 is opened and the second bypass valve BV2 is closed. At this time, the high-temperature refrigerant discharged from the compressor 2 flows into the outdoor heat exchanger 4, and the outdoor heat exchanger 4 acts as a condenser to defrost. However, the outdoor fan 9 is in a stopped state. And the first bypass valve BV1. of the bypass circuit. The refrigerant, which is reduced in pressure through the header 20 and turned into a liquid or two-phase state by the indoor first expansion valve EVla of the indoor unit 6a in the cooling mode, flows into the indoor heat exchanger 8a and absorbs heat from the room ( cooling operation). After that, the second two-way valve EV on the indoor side
It returns to the outdoor unit 1 via 2a.

As described above, headers are installed in multiple indoor units, two two-way valves and two expansion valves are installed in each indoor unit, a header is installed, and the outdoor expansion valve and header are installed. A bypass circuit via a two-way valve in between, a second bypass valve connecting between the compressor suction side and the outdoor heat exchanger, and between the compressor discharge side and the four-way valve, and a defrosting via a pressure reducer. forming a bypass circuit for cooling the indoor units during operation, and switching a four-way valve depending on the number of indoor units in heating operation, and a first bypass valve;
By providing a control means for controlling opening and closing of the second bypass valve, it becomes possible to realize simultaneous operation of cooling, heating, and defrosting.

In the above embodiment, the header 20 is connected to each indoor unit 6a, 6.
b, 6c have the same diameter specifications, but each indoor unit 6
The same effect can be obtained by installing dedicated headers for each of a, 6b, and 6c and connecting these headers with pipes of different diameters.

As described above, the outdoor unit and each indoor unit are connected by the indoor first two-way valve and the indoor second two-way valve, and the indoor first two-way valve and the indoor heat exchanger are connected to each other. A circuit is formed between the second indoor two-way valve and the indoor heat exchanger by a first indoor expansion valve, a header, and a second indoor expansion valve, and the outdoor expansion valve and the header. a bypass circuit via a first bypass valve between the Cooling is achieved by forming a defrosting bypass circuit and providing control means for cooling indoor units during defrosting operation, switching the four-way valve depending on the number of heating units in operation, and controlling the opening and closing of the first bypass valve and the second bypass valve. It becomes possible to realize simultaneous operation of , heating, and defrosting.

Effects of the Invention As described above, the present invention provides an outdoor unit comprising a compressor, a four-way valve, an outdoor heat exchanger, an outdoor blower, and an outdoor expansion valve;
Connect multiple indoor units in parallel, each consisting of a first indoor two-way valve, an indoor heat exchanger, an indoor blower, a second indoor two-way valve, a first indoor expansion valve, and a second indoor expansion valve. The outdoor unit and each indoor unit are connected by a first two-way valve on the indoor side and a second two-way valve on the indoor side. Forming a circuit connecting the inner heat exchanger, the indoor second two-way valve, and the indoor heat exchanger with the indoor first expansion valve, the header, and the indoor second expansion valve, and a bypass circuit via a first bypass valve between the outdoor expansion valve and the header, and a second bypass connecting between the compressor suction side and the outdoor heat exchanger and between the compressor discharge side and the four-way valve. valve.

A defrosting bypass circuit is formed via a pressure reducer, and control controls switching of the four-way valve and opening/closing of the first bypass valve and the second bypass valve depending on the number of indoor units in operation for cooling and heating during defrosting operation. By providing means for cooling, heating,
It becomes possible to realize simultaneous operation of defrosting and defrosting.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration system diagram of a heat pump air conditioner according to an embodiment of the present invention, Fig. 2 is a system diagram of input/output signals of the control device of the embodiment, and Fig. 3 explains the control operation of the embodiment. The flowchart, FIG. 4, is a refrigeration system diagram of a heat pump type air conditioner showing a conventional example. 1... Outdoor unit, 2... Compressor, 3... Four-way valve, 4
...Outdoor side heat exchanger, 5...Outdoor side expansion valve, 6a~
6c...Indoor unit, 8a-8C...Indoor heat exchanger,
9...Outdoor side blower, 10a-10c...Indoor side blower, Vla~■1c...Indoor side first two-way valve, V2a
~■2c"'Indoor side 2nd two-way valve, EVla"EVlc"
'Indoor side first expansion valve, EV 2 a = EV 2
C... Indoor side second expansion valve, 20... Header BVI
...first bypass valve, BV2...second bypass valve,
EXP... pressure reducer. Name of agent: Patent attorney Shigetaka Awano Haka 1 person Wi 2
rA Figure Figure

Claims (1)

[Claims] An outdoor unit consisting of a compressor, a four-way valve, an outdoor heat exchanger, an outdoor blower, and an outdoor expansion valve, a first indoor two-way valve, an indoor heat exchanger, an indoor blower, and a second indoor fan. A refrigeration cycle is provided in which a main circuit is formed by connecting a plurality of indoor units in parallel, each consisting of a double-sided valve, a first indoor expansion valve, and a second indoor expansion valve, and the outdoor unit and each indoor unit are connected to the indoor unit. The first two-way valve is connected to the indoor second two-way valve, and the first indoor two-way valve and the indoor heat exchanger are connected, and the indoor second two-way valve and the indoor heat exchanger are connected to each other. a circuit connecting the first expansion valve on the indoor side, the header, and the second expansion valve on the indoor side; a bypass circuit via the first bypass valve between the outdoor expansion valve and the header; and a bypass circuit connecting the compressor suction side with the header. A defrosting bypass circuit is formed via a second bypass valve that connects the outdoor heat exchanger, the compressor discharge side, and the four-way valve, and a pressure reducer, and cools the indoor unit during defrosting operation.
and a multi-room air conditioner equipped with a control means for controlling the switching of a four-way valve and the opening and closing of a first bypass valve and a second bypass valve depending on the number of units in heating operation.