JP2001272084A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner with excellent reliability capable of satisfactory dehumidification performance in an outdoor machine on a dehumidification side even when cooling operation and dehumidification operation are mixed in each indoor machine. SOLUTION: In the case where cooling operation and dehumidification operation are mixed in indoor machines B1, B2, capacity of a compressor 1 and capacity of an indoor fan 16 (or 26) of the cooling side indoor machine are controlled such that temperature T1 of a dehumidification heat exchanger 13 (or 23) in the indoor machine on the dehumidification side becomes a dehumidification level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-type air conditioner having an outdoor unit and a plurality of indoor units.

[0002]

2. Description of the Related Art In an outdoor unit having a compressor and an outdoor heat exchanger, and a multi-type air conditioner having a plurality of indoor units each having an indoor heat exchanger, an air conditioning load of a room where each indoor unit is installed is known. Is detected, and the operating frequency of the compressor is controlled according to the sum of these air conditioning loads. As a result, an optimal cooling capacity or heating capacity corresponding to the total air conditioning load can be obtained.

As an example of such a multi-type air conditioner, each outdoor unit is provided with a plurality of indoor heat exchangers for dehumidification, and the amount of refrigerant flowing into each indoor unit is adjusted by a flow control valve. In some cases, by controlling the temperature of each indoor heat exchanger, a cooling operation and a dehumidifying operation can be selectively executed in each indoor unit. The temperature (evaporation temperature) of the indoor heat exchanger during cooling is 10 to 13 ° C, and the temperature (evaporation temperature) of the indoor heat exchanger during dehumidification is about 5 to 8 ° C.

[0004]

As described above, in the air conditioner capable of selectively performing the cooling operation and the dehumidifying operation in each indoor unit, when the cooling operation and the dehumidifying operation are mixed in each indoor unit, each of Since the pipes on the downstream side of the indoor units are in communication with each other, the refrigerant pressures in the indoor heat exchangers of each indoor unit become almost equal, and the temperatures (evaporation temperatures) of the respective indoor heat exchangers are also balanced at almost the same value. Would.

Therefore, in the indoor unit on the dehumidification side, the temperature of the indoor heat exchanger for dehumidification rises to a cooling level (10 to 13 ° C.) higher than the original dehumidification level (5 to 8 ° C.). In such a case, sufficient dehumidifying performance cannot be obtained in the indoor unit on the dehumidifying side, which gives a feeling of discomfort to a person indoors.

[0006] The present invention has been made in view of the above circumstances,
The purpose is to provide a highly reliable air conditioner that can obtain sufficient dehumidifying performance in the indoor unit on the dehumidifying side even when cooling operation and dehumidifying operation are mixed in each indoor unit. is there.

[0007]

An air conditioner according to a first aspect of the present invention includes an outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units each having a plurality of indoor heat exchangers, and each indoor unit. Control means for selectively performing a cooling operation and a dehumidifying operation in each indoor unit by controlling each flow control valve, comprising a plurality of flow control valves for adjusting the amount of refrigerant flowing to the unit, When the cooling operation and the dehumidifying operation are mixed in each indoor unit, the control unit controls the capacity of the compressor so that the temperature of the indoor heat exchanger in the indoor unit on the dehumidifying side is at the dehumidifying level.

According to a second aspect of the present invention, in the air conditioner according to the first aspect, the indoor unit has first and second indoor heat exchangers.

According to a third aspect of the present invention, in the air conditioner according to the second aspect, the control means controls the compression so that the temperature of the first indoor heat exchanger of the indoor unit on the dehumidifying side becomes the dehumidifying level. Increase the capacity of the machine.

An air conditioner according to a fourth aspect of the present invention provides an outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units each having a plurality of indoor heat exchangers, and an amount of refrigerant flowing through each indoor unit. Control means for selectively performing a cooling operation and a dehumidifying operation in each indoor unit by controlling each flow control valve, comprising a plurality of flow control valves for adjusting the
When the cooling operation and the dehumidifying operation are mixed in each indoor unit, control means for controlling the air volume of the indoor blower in the indoor unit on the cooling side such that the temperature of the indoor heat exchanger in the indoor unit on the dehumidifying side becomes the dehumidification level. Have.

An air conditioner according to a fifth aspect of the present invention is the air conditioner according to the fourth aspect, wherein the indoor unit has first and second indoor heat exchangers.

According to a sixth aspect of the present invention, in the air conditioner according to the fifth aspect, the control means controls the cooling side so that the temperature of the first indoor heat exchanger in the indoor unit on the dehumidifying side is at the dehumidifying level. The air volume of the indoor blower in the indoor unit is reduced.

According to a seventh aspect of the present invention, in the air conditioner according to the first or second aspect, the indoor unit has first and second indoor heat exchangers, and these indoor heat exchangers are provided. A variable opening throttle valve is provided between both indoor units so that one of the units functions as an evaporator and the other functions as a condenser.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a plurality of indoor units B1 and B2 are connected by piping to an outdoor unit A to form a multi-type refrigeration cycle. The outdoor unit A has a compressor 1 and an outdoor heat exchanger 3. The indoor unit B1 has a plurality of indoor heat exchangers 13 and 14, of which the indoor heat exchanger 13 is used for dehumidification. The indoor unit B2 has a plurality of indoor heat exchangers 23 and 24, of which the indoor heat exchanger 23 is used for dehumidification. Hereinafter, the indoor heat exchangers 13 and 23 are referred to as dehumidifying heat exchangers 13 and 23.

The outdoor heat exchanger 3 is connected to a discharge port of the compressor 1 via a four-way valve 2, and a packed valve 12 is connected to the outdoor heat exchanger 3 via a flow control valve 11. The packed valve 12 is sequentially connected to the dehumidifying heat exchanger 13 and the indoor heat exchanger 14 of the indoor unit B1,
A packed valve 15 is connected to the indoor heat exchanger 14. The suction port of the compressor 1 is connected to the packed valve 15 via the four-way valve 2.

A packed valve 22 is connected to the outdoor heat exchanger 3 via a flow control valve 21. The packed valve 22 is sequentially connected to the dehumidifying heat exchanger 23 and the indoor heat exchanger 24 of the indoor unit B2, and the indoor heat exchanger 24 is connected to the packed valve 25. And
The suction port of the compressor 1 is connected to the packed valve 25 via the four-way valve 2.

The flow control valves 11 and 21 are pulse motor valves (PMV) whose opening degree continuously changes in accordance with the number of supplied driving pulses, and open and close the amount of refrigerant flowing through the indoor units B1 and B2. It has a function to adjust according to the degree change.

An outdoor fan 4 is provided near the outdoor heat exchanger 3. An outdoor blower 16 is provided near the dehumidifying heat exchanger 13 and the indoor heat exchanger 14. An outdoor blower 26 is provided near the dehumidifying heat exchanger 23 and the indoor heat exchanger 24.

A temperature sensor 31 is attached to the dehumidifying heat exchanger 13, and a temperature sensor 32 is attached to the indoor heat exchanger 14. A temperature sensor 33 is attached to a pipe between the packed valve 15 and the four-way valve 2.

A temperature sensor 41 is mounted on the dehumidifying heat exchanger 23, and a temperature sensor 42 is mounted on the indoor heat exchanger 24. A temperature sensor 43 is attached to a pipe between the packed valve 25 and the four-way valve 2.

FIG. 2 shows the control circuit.

The outdoor control unit 50 of the outdoor unit A is connected to the commercial AC power supply 51. The outdoor control unit 50 is connected to the flow control valves 11 and 21, the four-way valve 2, the outdoor blower motor 4M, the temperature sensors 33 and 43, and the inverter circuit 52. The inverter circuit 52 rectifies the voltage of the power supply 51,
It is converted into a voltage of a frequency (and level) according to the command of the outdoor control unit 50 and output. This output is the driving power of the compressor motor 1M.

The indoor units B1 and B2 are respectively
0 is provided. The indoor temperature sensor 3
0 (and 40), temperature sensors 31 and 32 (and 4
1, 42), the indoor blower motor 16M (and 26
M), the light receiving unit 61 is connected. The light receiving unit 61 receives infrared light emitted from a remote control type operation device (hereinafter, abbreviated as a remote control) 62.

The indoor control unit 60 and the outdoor control unit 50 are connected by a power supply line ACL and a data transmission serial signal line SL, respectively.

Each indoor control unit 60 has the following means [1] to [3] as main functions.

[1] Means for informing the outdoor unit A of operating conditions (including the set temperature Ts) by operating the remote controller 62 by a serial signal synchronized with the power supply voltage.

[2] Indoor temperature sensor 30 (and 40)
Detected temperature Ta and set temperature T set by remote controller 62
means for detecting a difference from the air conditioning load as the air conditioning load and informing the outdoor unit A of a required capacity corresponding to the air conditioning load.

[3] Temperature sensors 31, 32 (and 4)
1, 42) means for informing the outdoor unit A of the detected temperatures T1, T2.

The outdoor control section 50 has the following means [11] to [16] as main functions.

[11] When a cooling operation is requested from the indoor unit B1, the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the flow control valve 11, the dehumidifying heat exchanger 13, The flow is returned to the compressor 1 through the indoor heat exchanger 14 and the four-way valve 2, and the flow rate adjusting valve 11 is adjusted so that the difference between the detected temperature T2 of the temperature sensor 32 and the detected temperature T3 of the temperature sensor 33 becomes a set value. Means for controlling the opening.

[12] When a cooling operation is requested from the indoor unit B2, the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the flow control valve 21, the dehumidifying heat exchanger 23, The flow is returned to the compressor 1 through the indoor heat exchanger 24 and the four-way valve 2, and the flow rate regulating valve 21 is controlled so that the difference between the detected temperature T2 of the temperature sensor 42 and the detected temperature T3 of the temperature sensor 43 becomes a set value. Means for controlling the opening.

[13] When the dehumidifying operation is requested from the indoor unit B1, the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the flow regulating valve 11, the dehumidifying heat exchanger 13, The flow is returned to the compressor 1 through the indoor heat exchanger 14 and the four-way valve 2, and the flow rate adjusting valve 11 is adjusted so that the difference between the detected temperature T1 of the temperature sensor 31 and the detected temperature T2 of the temperature sensor 32 becomes a set value. Means for controlling the opening.

[14] When the indoor unit B2 requests the dehumidifying operation, the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the flow regulating valve 21, the dehumidifying heat exchanger 23, The flow is returned to the compressor 1 through the indoor heat exchanger 24 and the four-way valve 2, and the flow rate adjusting valve 21 is adjusted so that the difference between the detected temperature T1 of the temperature sensor 41 and the detected temperature T2 of the temperature sensor 42 becomes a set value. Means for controlling the opening.

[15] Means for controlling the capacity of the compressor 1 (output frequency F of the inverter circuit 52) in accordance with the sum of the required capacity from each indoor unit.

[16] When the cooling operation and the dehumidifying operation are mixed in the indoor units B1 and B2, the capacity of the compressor 1 is set so that the temperature (T1) of the dehumidifying heat exchanger 13 in the dehumidifying-side indoor unit is at the dehumidifying level. Control means for controlling the

Next, the operation of the above configuration will be described with reference to the flowchart of FIG.

It is assumed that the dehumidifying operation is requested by the indoor unit B1, and the cooling operation is requested by the indoor unit B2.

In this case, in the indoor unit B1 on the dehumidifying side, the temperature (evaporation temperature) T1 of the dehumidifying heat exchanger 13 detected by the temperature sensor 31 and the temperature T2 of the indoor heat exchanger 14 detected by the temperature sensor 32. The opening of the flow control valve 11 is controlled so that the difference between the flow rate adjustment value and the set value becomes the set value. By this opening degree control, a dehumidifying operation is performed in the indoor unit B1.

In the indoor unit B2 on the dehumidifying side, the temperature sensor 32
Of the indoor heat exchanger 14 (evaporation temperature) T2
The opening of the flow control valve 21 is controlled such that the difference between the temperature and the gas-side refrigerant temperature T3 detected by the temperature sensor 33 becomes a set value. By this opening control, the cooling operation is performed in the indoor unit B2.

The relationship between the evaporating temperature and the cooling capacity when the dehumidifying operation and the cooling operation coexist is shown by using the heat exchanger performance (heat exchange amount) and the compressor performance (= compressor rotation speed) as parameters. 4. The broken line indicates the heat exchanger capacity, and the solid line indicates the compressor speed.

That is, first, in the dehumidifying operation in the indoor unit B1, the operating frequency F is set low, and the compressor 1 is operated at a low rotation speed (low capacity). The opening of the flow control valve 11 is controlled in accordance with the difference between the detected temperatures T1 and T2 so that the compressor 1 and the dehumidifying heat exchanger 13 exhibit the maximum capacity. Match at point a.

When the cooling operation of the indoor unit B2 is started from this state, the operating frequency F is increased based on the sum of the required capacity of the indoor units B1 and B2, and the compressor 1 is rotated at a medium speed (medium capacity). Driven by As a result, the dehumidifying heat exchanger 13 of the indoor unit B1 and the heat exchangers 23, 2 of the indoor unit B2.
The matching point between the performance of the heat exchanger as a whole and the performance of the compressor together with b is b.

However, since the pipes downstream of the indoor units B1 and B2 are in communication with each other, the refrigerant pressure in the dehumidifying heat exchanger 13 of the indoor unit B1 and the heat exchanger 2 of the indoor unit B2
The refrigerant pressure in the heat exchangers 3 and 24 is almost equal, and the temperature (evaporation temperature) of the dehumidifying heat exchanger 13 and the heat exchangers 23 and
The temperature 24 (evaporation temperature) is balanced at a cooling level (10 to 13 ° C.) having substantially the same value.

Therefore, when viewed from the indoor unit B1 on the dehumidifying side,
The matching point between the heat exchanger performance of only the dehumidifying heat exchanger 13 and the compressor performance is bx, and the dehumidifying ability is reduced as shown by the broken line in FIG.

When the temperature T1 of the dehumidifying heat exchanger 13 is higher than the dehumidifying level (5 to 8 ° C.) Tx,
The operating frequency F is corrected in the increasing direction so that 1 falls to Tx. As the capacity of the compressor 1 is increased in this way, the matching point between the heat exchanger performance of only the dehumidifying heat exchanger 13 and the compressor performance shifts to cx, and the dehumidifying capacity substantially equal to the above matching point a. Can be obtained.

Since the total cooling capacity has increased from point b to point c, the capacity becomes excessive in the indoor unit B2 on the cooling side, and the detected temperature Ta of the indoor temperature sensor 40 drops to the set indoor temperature Ts, thereby turning off the thermostat. And the flow control valve 21 is fully closed. At this time, the operating frequency F is lowered, and the heat exchanger performance and the compressor performance match again at the point a.

Thus, air conditioning is performed in the indoor unit B2 on the cooling side so that the indoor temperature Ta becomes the set indoor temperature Ts, and the indoor unit B1 on the dehumidifying side can exhibit sufficient dehumidifying performance.

In the above embodiment, the dehumidifying performance is ensured by controlling the capacity of the compressor 1. However, instead of controlling the capacity of the compressor 1, the air volume of the indoor blower is controlled. Can obtain the same effect.

That is, as shown in the flowchart of FIG. 6, the temperature T1 of the dehumidifying heat exchanger 13 is changed to the dehumidifying level (5
-8 ° C.), the indoor blower 16 of the indoor unit B1 on the cooling side is set so that T1 drops to Tx.
Is reduced.

With the reduction of the air volume, as shown by the arrow in FIG. 7, the performance of the entire heat exchanger decreases, and the matching point between the performance of the entire heat exchanger and the compressor performance shifts from b to c. As a result, the evaporation temperature is reduced, and sufficient dehumidification performance can be obtained.

In this case, since the matching point shifts from b to c and the cooling capacity is also reduced, there is a concern that the indoor unit B2 on the cooling side may be uncomfortable, but this point is compensated for by increasing the capacity of the compressor 1. be able to.

As shown in FIG. 8, a refrigeration cycle is provided with a variable-opening throttle valve (PMV) 16 between the dehumidifying heat exchanger 13 and the indoor heat exchanger 14, and A throttle valve (PM) between the heat exchanger 23 and the indoor heat exchanger 24
V) 26 can be similarly implemented. The throttle valve 16 (and 26) is connected to the heat exchangers 13, 14 (2
3, 24) to function as an evaporator and the other to function as a condenser.

When the dehumidifying operation is performed in the indoor unit B1, the opening of the throttle valve 16 is controlled so that the flow regulating valve 11 is fully opened and the difference between the detected temperatures T2 and T3 becomes a set value. The heat exchanger 13 functions as an evaporator, and the indoor heat exchanger 14 functions as a condenser.

The present invention is not limited to the steam embodiment, but can be variously modified without changing the gist.

[0056]

As described above, according to the present invention, when the cooling operation and the dehumidifying operation are mixed in each indoor unit, the compression is performed so that the temperature of the indoor heat exchanger in the indoor unit on the dehumidifying side becomes the dehumidifying level. Since the capacity of the unit or the air flow rate of the indoor blower of the cooling-side indoor unit is controlled, even when the cooling operation and the dehumidifying operation are mixed in each indoor unit, sufficient dehumidifying performance can be obtained in the indoor unit on the dehumidifying side. An air conditioner with excellent reliability can be provided.

[Brief description of the 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 of a control circuit according to the embodiment;

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

FIG. 4 is a view showing a relationship between an evaporating temperature and a cooling capacity in the embodiment, using heat exchanger performance and compressor performance as parameters.

FIG. 5 is a view showing a change in dehumidification performance in the embodiment.

FIG. 6 is a flowchart for explaining the operation of a modification of the embodiment.

FIG. 7 is a diagram showing a relationship between an evaporating temperature and a cooling capacity in the modification with heat exchanger performance and compressor performance as parameters.

FIG. 8 is a diagram showing a configuration of a refrigeration cycle according to another modification of the embodiment.

[Explanation of symbols]

A: outdoor unit, B1, B2: indoor unit, 1 ... compressor, 2 ... four-way valve, 3 ... outdoor heat exchanger, 11, 21 ... flow control valve, 1
3, 23: heat exchanger for dehumidification, 14, 24: indoor heat exchanger, 31, 32, 33: temperature sensor, 50: outdoor controller, 60: indoor controller

Claims (7)

[Claims] 1. An outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units each having a plurality of indoor heat exchangers, and a plurality of flow control valves for adjusting the amount of refrigerant flowing through each indoor unit. In an air conditioner provided with: a control unit that selectively executes a cooling operation and a dehumidifying operation in each of the indoor units by controlling the flow rate control valves, and a cooling operation and a dehumidifying operation are mixed in each of the indoor units. Control means for controlling the capacity of the compressor so that the temperature of the indoor heat exchanger in the indoor unit on the dehumidifying side is at the dehumidifying level. 2. The air conditioner according to claim 1, wherein the indoor unit has first and second indoor heat exchangers. 3. The air conditioner according to claim 2, wherein the control unit increases the capacity of the compressor so that the temperature of the first indoor heat exchanger in the dehumidification-side indoor unit is at the dehumidification level. . 4. An outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units each having a plurality of indoor heat exchangers, and a plurality of flow control valves for adjusting an amount of refrigerant flowing through each indoor unit. In an air conditioner provided with: a control unit that selectively executes a cooling operation and a dehumidifying operation in each of the indoor units by controlling the flow rate control valves, and a cooling operation and a dehumidifying operation are mixed in each of the indoor units. Control means for controlling the air volume of the indoor blower in the indoor unit on the cooling side so that the temperature of the indoor heat exchanger in the indoor unit on the dehumidifying side becomes the dehumidification level. 5. The air conditioner according to claim 4, wherein the indoor unit has first and second indoor heat exchangers. 6. The air conditioner according to claim 5, wherein the control unit is configured to control the temperature of the first indoor heat exchanger of the indoor unit on the dehumidifying side to be at the dehumidifying level. To reduce the air volume. 7. The air conditioner according to claim 1, wherein the indoor unit has first and second indoor heat exchangers,
In addition, a throttle valve with a variable opening degree is provided between both indoor units so that one of the indoor heat exchangers functions as an evaporator and the other functions as a condenser.