JPH0727436A - Air conditioner - Google Patents

Abstract

PURPOSE:To provide an air conditioner in which indoor units of all capacities can be connected to an outdoor unit and a connecting variation can be increased. CONSTITUTION:A plurality of indoor units B are connected to an outdoor unit A. The units B have intrinsic capacities, and the unit A has an intrinsic capacity. The unit A has necessary minimum refrigerant circulation amount, normally operates when a sum of the capacities of the indoor units to be required is a set value or more based on the necessary minimum circulation amount, and opens a flow control valve 32 corresponding to the indoor unit B of a stop mode and the indoor unit B of a thermostat-off based on indoor temperature control by a predetermined opening when the value becomes a set value or less, and feeds a small amount of refrigerant to the non-operated unit B, thereby obtaining the refrigerant circulation amount of necessary minimum limit for the operation of the outdoor unit A.

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 In a building having a large number of rooms, a multi-type air conditioner having a plurality of indoor units is used. The air conditioner includes an outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units each having a flow rate adjusting valve and an indoor heat exchanger, and a compressor, an outdoor heat exchanger, each flow rate adjusting valve, The indoor heat exchangers are connected to form a refrigeration cycle.

A plurality of types of indoor units are prepared according to the place where they are installed and their uses, and each unit has its own capacity (horsepower). The outdoor unit also has its own capacity (horsepower), which corresponds to the maximum capacity that can be exhibited, and the connection variation of the indoor units is selected so that the total value of the capacity of each indoor unit falls within that capacity. It For example, if the capacity of the outdoor unit is 10 hp, the total capacity of the connected indoor units is 10
Choices are made to stay within horsepower.

[0004]

There is a minimum amount of refrigerant circulation required for the operation of the outdoor unit, and only an indoor unit having a capacity that can satisfy the required minimum amount of refrigerant circulation can be connected. In other words, there are restrictions on connection variations.

However, recently, the use of personal air conditioning units for individuals has become popular. This is a small-capacity indoor unit that can be attached to a desk, etc., and is small as 0.15 horsepower, so it will be disconnected from the connection target.

The present invention takes the above circumstances into consideration,
An object of the invention is to provide an air conditioner capable of connecting an indoor unit of any capacity to an outdoor unit and expanding connection variations.

[0007]

An air conditioner according to a first aspect of the invention includes an outdoor unit having a compressor and an outdoor heat exchanger, and a plurality of indoor units each having a flow rate adjusting valve and an indoor heat exchanger, A refrigeration cycle in which a compressor, an outdoor heat exchanger, each flow rate adjusting valve, and each indoor heat exchanger are connected, a means for controlling the capacity of the compressor according to the required capacity of each indoor unit, and the opening of each flow rate adjusting valve. Control unit according to the required capacity of each indoor unit, and when the total value of the capacity of the indoor units that require operation is less than or equal to the set value, set the flow rate control valve corresponding to the indoor unit that does not require operation to the specified opening. And means for opening only.

In the air conditioner of the second aspect of the invention, in the configuration of the first aspect of the invention, the indoor unit that does not require operation is an indoor unit in a stop mode. In the air conditioner of a third aspect of the invention, in the configuration of the first aspect of the invention, the indoor unit that does not require operation is a thermo-off indoor unit based on indoor temperature control.

[0009]

In the air conditioner according to the first aspect of the invention, when the total value of the capacities of the indoor units that require operation is less than or equal to the set value, the flow control valves corresponding to the indoor units that do not require operation are opened by a predetermined opening, By flowing a small amount of refrigerant through the non-operating indoor unit, a minimum amount of refrigerant circulation necessary for operating the outdoor unit is secured.

In the air conditioner of the second invention, when the total value of the capacities of the indoor units requiring operation is less than or equal to the set value,
The minimum flow rate of refrigerant required for operation of the outdoor unit is ensured by opening the flow control valve corresponding to the indoor unit in the stop mode that does not require operation by a predetermined opening and flowing a small amount of refrigerant to the non-operation indoor unit. To do.

In the air conditioner of the third invention, when the total value of the capacities of the indoor units required to operate is less than or equal to the set value,
The minimum flow rate of refrigerant required to operate the outdoor unit is secured by opening the flow control valve corresponding to the thermo-off indoor unit that does not require operation by a predetermined degree and flowing a small amount of refrigerant to the non-operating indoor unit. .

[0012]

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 to which a plurality of indoor units B are connected by piping and wiring.

The outdoor unit A includes compressors 1 and 2 housed in a common closed case. The compressor 1 is an inverter-driven variable capacity compressor. The compressor 2 is a commercial power source driven fixed capacity compressor.

The high pressure side pipe 4 is connected to the discharge port of the compressor 1. The high pressure side pipe 4 is connected to the discharge port of the compressor 1 via the check valve 3. The low-pressure side pipe 5 is connected to the suction ports of the compressors 1 and 2.

An outdoor heat exchanger 8 is connected to the high pressure side pipe 4 via an oil separator 6 and a four-way valve 7. A dryer 11 is connected to the outdoor heat exchanger 8 via a check valve 9 and a liquid tank 10. Check valve 9 and heating expansion valve 1
Connect 2 in parallel. An outdoor fan 13 is provided near the outdoor heat exchanger 8.

A strainer 15 is connected to the low-pressure side pipe 5 via an accumulator 14 and a four-way valve 7. The oil separator 6 extracts the lubricating oil contained in the refrigerant discharged from the compressors 1 and 2. A pipe 16 for returning oil is connected from the oil separator 6 to the low-pressure side pipe 5.

One end of a cooling bypass 17 is connected to a gas line pipe between the check valve 9 and the liquid tank 10. The other end of this cooling bypass 17 is connected to the pipe of the low pressure line between the four-way valve 7 and the accumulator 14. Then, the opening variable valve 18 is attached to the cooling bypass 17.
To provide.

A high pressure switch 21 and a refrigerant temperature sensor 25 are provided in a pipe extending from the discharge port of the compressor 1 to the high pressure side pipe 4.
Install. A high pressure switch 22 and a refrigerant temperature sensor 26 are attached to a pipe extending from the discharge port of the compressor 2 to the check valve 3. The high pressure switches 21 and 22 are activated when the pressure of the refrigerant rises abnormally and reaches a predetermined value.

A refrigerant pressure sensor 23 is attached to the high pressure side pipe 4. A refrigerant pressure sensor 24 and a refrigerant temperature sensor 27 are attached to the low pressure side pipe 5. The heat exchanger temperature sensor 28 is attached to the outdoor heat exchanger 8. An outdoor air temperature sensor 29 is attached to a predetermined portion of the outdoor unit A.

Between the dryer 11 and the strainer 15,
Strainer 31 and flow rate adjustment valve 32 of indoor unit B
The indoor heat exchanger 33 is connected via. Indoor heat exchanger 3
An indoor fan 34 is provided in the vicinity of 3. And PMV3
The refrigerant pressure sensor 35 and the refrigerant temperature sensor 37 are attached to the pipe of the liquid line between the 2 and the indoor heat exchanger 33. The refrigerant pressure sensor 36 and the refrigerant temperature sensor 38 are attached to the pipe of the gas line connected to the indoor heat exchanger 33. An indoor temperature sensor 39 is provided in the passage of the intake air of the indoor fan 34. The other indoor units B have the same configuration and the same connection.

With such pipe connections, the outdoor unit A and each indoor unit B constitute a heat pump type refrigeration cycle. During cooling, the four-way valve 7 is set to a neutral state, whereby the refrigerant discharged from the compressors 1 and 2 is caused to flow in the direction of the solid line arrow in the drawing to form a cooling cycle, and the outdoor heat exchanger 8 is connected to the condenser, Each indoor heat exchanger 33
Function as an evaporator. During heating, the four-way valve 7 is switched, whereby the refrigerant discharged from the compressors 1 and 2 is caused to flow in the direction of the broken line arrow in the drawing to form a heating cycle, and each indoor heat exchanger 33 is replaced with a condenser and outdoor heat exchange. The container 8 functions as an evaporator.

The opening variable valve 18 and each flow rate adjusting valve 3
Reference numeral 2 is a pulse motor valve whose opening continuously changes according to the number of input drive pulses. Hereinafter, the variable opening valve and the flow rate adjusting valve are abbreviated as PMV.

The control circuit is shown in FIG. The outdoor unit A includes an outdoor controller 50. The indoor control unit 60 of each indoor unit B is wire-connected to the outdoor control unit 50.

The outdoor controller 50 comprises a microcomputer and its peripheral circuits. In this outdoor control unit 50,
Four-way valve 7, outdoor fan motor 13M, PMV 18, high pressure switches 21, 22, refrigerant pressure sensors 23, 24, refrigerant temperature sensors 25, 26, 27, heat exchanger temperature sensor 2
8, outside air temperature sensor 29, commercial AC power supply 51, inverter
Switch 52 and switch 53 are connected.

The inverter 52 rectifies the voltage of the AC power supply line in the outdoor control unit 50, converts it into a voltage of a predetermined frequency by switching according to a command from the outdoor control unit 50, and outputs it. This output becomes the drive power for the compressor motor 1M.

The switch 53 is, for example, a contact of an electromagnetic contactor. The compressor motor 2M is connected to the AC power supply line in the outdoor control unit 50 via the switch 53. The indoor control unit 60 is composed of a microcomputer and its peripheral circuits. The indoor control unit 60 includes a PMV 32, an indoor fan motor 34M, refrigerant pressure sensors 35 and 36, refrigerant temperature sensors 37 and 38, an indoor temperature sensor 39, and a remote control type operation device (hereinafter, abbreviated as remote controller) 61.
Connect.

The indoor control unit 60 has the following functional means. [1] A means for sending an operation mode command, an operation start command, and an operation stop command to the outdoor unit A based on the operation of the remote controller 61.

[2] Means for informing the outdoor unit A of the required capacity corresponding to the temperature difference ΔT between the temperature Ta (intake air temperature) Ta detected by the indoor temperature sensor 39 and the set temperature Ts set by the remote controller 61. .

[3] A means for controlling the opening of the PMV 32 according to the required capacity of the indoor unit. [4] A means for notifying the outdoor unit A of the capacity (horsepower) of the indoor unit.

[5] During cooling, the temperature detected by the refrigerant temperature sensor 38 attached to the gas line (evaporator outlet temperature) T _c2
And the pressure detected by the refrigerant pressure sensor 36 (evaporation pressure) P _c2
To means for detecting the degree of superheat of the refrigerant in the indoor heat exchanger 33.

[6] During heating, from the temperature detected by the refrigerant temperature sensor 37 (condenser outlet temperature) T _c1 attached to the liquid line and the pressure detected by the refrigerant pressure sensor 35 (condensation pressure) P _c1 to the cold room heat exchanger. 33 means for detecting the degree of supercooling of the refrigerant.

[7] A means for correcting the opening of the PMV 32 so that the detected degree of superheat or degree of supercooling becomes a constant value. The outdoor control unit 50 includes the following functional means.

[1] When the compressors 1 and 2 are started, their operating capacities (the number of operating compressors 1 and 2 and the operating frequency F of the compressor 1) are determined according to the total required capacity from each indoor unit B. Means to control.

[2] The four-way valve 7 is set to the neutral state, and the refrigerant discharged from the compressors 1 and 2 is transferred to the four-way valve 7, the outdoor heat exchanger 8, each flow rate adjusting valve 32, each indoor heat exchanger 33, and the four-way valve. 7
Means for returning to the compressors 1 and 2 through the air conditioner to execute the cooling operation.

[3] The four-way valve 7 is switched, and the refrigerant discharged from the compressors 1 and 2 is passed through the four-way valve 7, each indoor heat exchanger 33, each flow rate adjusting valve 32, the outdoor heat exchanger 8, and the four-way valve 7. Compressor 1,
A means for returning to 2 and performing heating operation.

[4] Means for executing the defrosting operation on the outdoor heat exchanger 8 according to the temperature Te detected by the heat exchanger temperature sensor 28 during heating. [5] The detected pressure Pd of the refrigerant pressure sensor 23 abnormally rises to a set value (lower than the operating points of the high pressure switches 21 and 22).
First high pressure protection means for reducing the capacity (operating frequency F) of the compressor 1 by a predetermined value.

[6] Second high pressure protection means for stopping the operation of the compressor 1 when the high pressure switch 21 is activated and stopping the operation of the compressor 2 when the high pressure switch 22 is activated. [7] Temperature detected by refrigerant temperature sensor 25 (discharged refrigerant temperature)
When either one of T _d1 and the temperature detected by the refrigerant temperature sensor 26 (discharged refrigerant temperature) T _d2 rises to the set value T dx,
A means for opening the PMV 18 of the cooling bypass 17 and controlling the opening of the PMV 18 according to the higher one of T _d1 and T _d2 .

[8] A means for opening the PMV 32 corresponding to the indoor unit not issuing the operation request by a predetermined opening when the total value of the capacities of the indoor units issuing the operation request is less than the set value. The set value corresponds to the minimum amount of refrigerant circulation required to operate the outdoor unit A.

Here, examples of connection variations of the outdoor unit A and each indoor unit B are shown in FIGS. 3 and 4. Next, the operation of the above configuration will be described with reference to the flowchart of FIG.

The user sets a desired operation mode and an indoor temperature (hereinafter referred to as a set temperature) Ts in the arbitrary indoor unit B by using the remote controller 61. Further, the operation for starting the operation is performed.

Then, at least the compressor 1 of the compressors 1 and 2 is started and the operation is started. In the cooling operation mode, the four-way valve 7 is set in the neutral state, the refrigerant flows in the direction of the solid arrow in FIG. 1, and the cooling cycle is formed. Thereby, the outdoor heat exchanger 8 functions as a condenser, and the indoor heat exchanger 33 functions as an evaporator. In the heating operation mode, the four-way valve 7 is switched and the refrigerant flows in the direction of the dashed arrow in FIG. 1 to form the heating cycle. Thereby, the indoor heat exchanger 33 functions as a condenser, and the outdoor heat exchanger 8 functions as an evaporator.

The indoor unit B obtains a difference ΔT between the temperature Ta (intake air temperature) Ta detected by the indoor temperature sensor 39 and the set temperature Ts set by the remote controller 61, and the outdoor unit A is given a required capacity corresponding to the temperature difference ΔT. Inform. Furthermore, PMV
The opening degree of 32 is set to an opening degree according to the temperature difference ΔT.

When the outdoor units A start up the compressors 1 and 2, the operating capacity (the number of operating compressors 1 and 2 and the operating frequency F of the compressor 1) is the sum of the required capacity from each indoor unit B. Set the operating capacity according to.

For example, when the total required capacity is small, the output frequency F of the inverter 52 is controlled to control the compressor 1
The single variable capacity operation of is executed. When the total required capacity increases, the output frequency F of the inverter 52 is controlled, the switch 53 is turned on, and the variable capacity operation of the compressor 1 and the fixed capacity operation of the compressor 2 are executed.

In the indoor unit B, during cooling, the indoor heat exchange is performed from the temperature (evaporator outlet temperature) T _c2 detected by the refrigerant temperature sensor 38 and the pressure (evaporation pressure) P _c2 detected by the refrigerant pressure sensor 36 in the gas line. The degree of superheat of the refrigerant in the container 33 is detected. During heating, from the temperature detected by the refrigerant temperature sensor 37 (condenser outlet temperature) T _c1 in the liquid line and the pressure detected by the refrigerant pressure sensor 35 (condensation pressure) P _c1 to the degree of supercooling of the refrigerant in the cold room heat exchanger 33. To detect.
Then, the opening degree of the PMV 32 is corrected so that the detected degree of superheat or degree of supercooling becomes a constant value.

On the other hand, in the outdoor unit A, the high pressure side pressure Pd is detected by the refrigerant pressure sensor 23, and the high pressure side pressure Pd is abnormally increased, and the set value (high pressure switch 21,
22 (lower than the operating point of 22), the capacity (operating frequency F) of the compressor 1 is reduced by a predetermined value. By this capacity reduction, the abnormal increase of the high pressure side pressure Pd is prevented, and the compressor 1,
Protect the refrigeration cycle equipment including 2.

However, in spite of this capacity reduction, when the high-pressure side pressure continues to rise abnormally and the high-pressure switch 21 operates, the operation of the compressor 1 is stopped. Further, when the high pressure switch 22 operates, the operation of the compressor 2 is stopped. This stoppage of operation reliably protects the refrigeration cycle equipment.

Also on the low pressure side, the low pressure side pressure Ps is detected by the refrigerant pressure sensor 24, and when the low pressure side pressure Ps abnormally rises to a predetermined value or more, the capacity (operating frequency F) of the compressor 1 is changed. Reduce by a predetermined value.

In the outdoor unit A, the refrigerant temperature sensor 25 detects the discharged refrigerant temperature T _d1 of the compressor 1, and the refrigerant temperature sensor 26 detects the discharged refrigerant temperature T _d2 of the compressor 2. When one of the detected temperatures rises to the set value Tdx, the PMV 18 of the cooling bypass 17 is opened. Then, the opening degree of the PMV 18 is controlled in proportion to the higher one of the detected temperatures T _d1 and T _d2 .

By thus opening the PMV 18, a part of the liquid refrigerant flowing through the liquid line is cooled.
Through to the suction side of the compressors 1, 2. Since the temperature of the liquid refrigerant flowing in is low, a cooling action is exerted on the compressors 1 and 2, and an abnormal increase in the discharge refrigerant temperature or the suction refrigerant temperature is suppressed. Therefore, the refrigeration cycle equipment is also protected by the control of this cooling bypass.

During heating, the outdoor heat exchanger 8 gradually becomes frosted as the operation proceeds, and the heat exchange amount decreases and the heating capacity becomes insufficient as it is. Therefore, the outdoor heat exchanger 8 is set by the heat exchanger temperature sensor 28.
When the detected temperature Te falls below a set value, for example, 0 ° C. or below, the defrosting operation for the outdoor heat exchanger 8 is executed.

In this defrosting operation, the four-way valve 7 is returned to the neutral state to form the same defrosting cycle as the cooling cycle, and the refrigerant (high temperature refrigerant) discharged from the compressors 1 and 2 is supplied to the outdoor heat exchanger 8. . By supplying this high-temperature refrigerant, the frost adhering to the outdoor heat exchanger 8 can be thawed.

When defrosting progresses and the temperature Te detected by the heat exchanger temperature sensor 28 becomes higher than 0 ° C., for example, 2 ° C. or more,
The four-way valve 7 is switched to return to the heating operation. By the way, the capacity of the outdoor unit A is 10 horsepower, the minimum amount of refrigerant circulation required for the operation of the outdoor unit A is equivalent to 2.0 horsepower (= set value), and the capacity of each indoor unit B is as shown in the example of FIG.
It is assumed that 1.0 horsepower and 0.15 horsepower are mixed.

In this case, 2 of 1.0 horsepower indoor unit B
Assuming that the vehicle makes an operation request, the total value of its capacity is
Since it is 2.0 horsepower and satisfies 2.0 horsepower, which is the set value based on the minimum required refrigerant circulation amount of the outdoor unit A, normal operation is performed.

That is, in the normal operation, the opening degree of the PMV 32 corresponding to the indoor unit B which issues the operation request is set to the opening degree corresponding to the required capacity of each indoor unit B. For the indoor unit B that has not issued the operation request, the corresponding PMV 32 is fully closed. Further, when the indoor unit B that has issued the operation request and is actually in the operation mode reaches the set temperature Ts and the required capacity becomes zero, the indoor unit B fully closes the corresponding PMV 32 to perform indoor heat exchange. The flow of the refrigerant into the container 33 is stopped and the operation is interrupted. That is, it is a thermo-off based on the indoor temperature control.

The indoor unit B in the operation mode responds to the operation stop operation by the user with the remote controller 61, and the PMV 32
Is fully closed and the stop mode is entered. It is also assumed that there is one indoor unit B that is issuing an operation request and the capacity of the indoor unit B is 1.0 horsepower or 0.15 horsepower. in this case,
Since the total value of the capacity is 1.0 horsepower or 0.15 horsepower and does not satisfy the set value of 2.0 horsepower, the PMVs 32 respectively corresponding to the indoor unit B in the stop mode and the indoor unit B in the thermo-off are opened by a predetermined opening degree.

In this way, by opening the PMV 32 by a predetermined opening degree, a small amount of refrigerant flows into the indoor unit B in the stop mode and the indoor unit B in the thermo-off mode, and the minimum amount of refrigerant circulation required for the operation of the outdoor unit A is reduced. Secured.

Therefore, even a small-capacity indoor unit B that cannot satisfy the required minimum refrigerant circulation amount of the outdoor unit A, such as a personal air conditioning unit for individuals, can be connected and connected. The variation can be expanded.

In the above embodiment, the PMV 32 corresponding to the indoor unit B in the stop mode and the thermo-off has a predetermined opening, but as shown in the flowchart of FIG. 6, only the indoor unit B in the stop mode is supported. P
The MV 32 may be configured to open by a predetermined opening. Also, FIG.
As shown in the flowchart of FIG. 5, the PMV 32 corresponding to only the indoor unit B that is in the thermo-off state may be opened by a predetermined opening degree.

[0060]

As described above, in any of the air conditioners of the first, second and third aspects of the present invention, when the total value of the capacity of the indoor units requiring the operation is less than or equal to the set value, the operation is required. Not open the flow control valve corresponding to the indoor unit by a predetermined opening degree, so that the minimum amount of refrigerant circulation necessary for the operation of the outdoor unit is ensured by flowing a small amount of refrigerant to the non-operating indoor unit. An indoor unit of any capacity can be connected to the outdoor unit, and the connection variation can be expanded.

[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 a configuration of a control circuit of the same embodiment.

FIG. 3 is a diagram showing an example of connection variations according to the embodiment.

FIG. 4 is a diagram showing an example of connection variations according to the embodiment.

FIG. 5 is a flowchart for explaining the operation of the embodiment.

FIG. 6 is a flowchart for explaining an operation of a modified example of the same embodiment.

FIG. 7 is a flowchart for explaining an operation of a modified example of the same embodiment.

[Explanation of symbols]

A ... Outdoor unit, B ... Indoor unit, 1 ... Variable capacity compressor, 2 ... Fixed capacity compressor, 8 ... Outdoor heat exchanger, 32 ...
PMV (flow rate adjusting valve), 33 ... Indoor heat exchanger, 50 ... Outdoor control unit, 60 ... Indoor control unit.

Claims (3)

[Claims] 1. An outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units each having a flow rate adjusting valve and an indoor heat exchanger, the compressor, the outdoor heat exchanger, each flow rate adjusting valve, A refrigeration cycle to which each indoor heat exchanger is connected, a means for controlling the capacity of the compressor according to the required capacity of each indoor unit, and the opening degree of each flow rate adjusting valve according to the required capacity of each indoor unit. A means for controlling and a means for opening a flow control valve corresponding to an indoor unit that does not require operation by a predetermined opening when the total value of the capacities of the indoor units that require operation is less than or equal to a set value. An air conditioner. 2. The air conditioner according to claim 1, wherein the indoor unit that does not require operation is an indoor unit in a stop mode. 3. The air conditioner according to claim 1, wherein the indoor unit that does not require operation is a thermo-off indoor unit based on indoor temperature control.