JP3330194B2 - Air conditioner - Google Patents

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 comprising 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. This air conditioner has an outdoor unit having a compressor and an outdoor heat exchanger, each including a plurality of indoor units having a flow control valve and an indoor heat exchanger, a compressor, an outdoor heat exchanger, each flow control valve, Each indoor heat exchanger is connected to form a refrigeration cycle.

[0003] Each indoor unit is provided with a plurality of types according to a place where it is installed and a use, and each unit has a specific capacity (horsepower). The outdoor unit also has a specific capacity (horsepower), which corresponds to the maximum capacity that can be exhibited, and the connection variation of the indoor unit is selected so that the total value of the capacity of each indoor unit falls within that capacity You. For example, if the capacity of the outdoor unit is 10 horsepower, the total value of the capacity of the connected indoor units is 10
A choice is made to fit within the horsepower.

[0004]

The operation of the outdoor unit has a required minimum amount of circulating refrigerant, and only an indoor unit having a capacity capable of satisfying the required minimum amount of circulating refrigerant can be connected. That is, there are restrictions on connection variations.

However, recently, use of personal air conditioning units for individuals has been increasing. This is a small-capacity indoor unit that can be mounted on a desk or the like.

[0006] The present invention has been made in view of the above circumstances,
An object of the present invention is to provide an air conditioner in which indoor units of any capacity can be connected to outdoor units and connection variations can be expanded.

[0007]

An air conditioner according to the present invention comprises an outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units each having a flow control valve and an indoor heat exchanger, and a compressor. Refrigeration cycle to which the outdoor heat exchanger, each flow control valve, each indoor heat exchanger is connected, means for controlling the capacity of the compressor according to the required capacity of each indoor unit, and the opening degree of each flow control valve Means for controlling according to the required capacity of each indoor unit, and when the total value of the capacity of the indoor unit requiring operation is equal to or less than the set value corresponding to the minimum refrigerant circulation amount required for operation of the outdoor unit, Open the flow control valve corresponding to the indoor unit that requires the operation to the opening degree corresponding to the required capacity, and do not request the operation
Based on indoor unit or indoor temperature control in stop mode
The flow control valve corresponding to the indoor unit of the Ku thermo-off and a means for opening a predetermined opening degree, its operating indoor unit
In addition to supplying refrigerant according to the required capacity,
By flowing a small amount of refrigerant through the
Ensure the required minimum amount of refrigerant circulation .

[0008]

[0009]

In the air conditioner of the present invention, when the total value of the capacity of the indoor unit requiring the operation is equal to or less than the set value corresponding to the minimum refrigerant circulation amount required for the operation of the outdoor unit, the operation is requested. Opening the flow control valve corresponding to the indoor unit to the opening corresponding to the required capacity and controlling the indoor unit or indoor temperature in the stop mode that does not require operation
By opening the flow control valve corresponding to the indoor unit of the thermo-off based on the predetermined opening degree, and flowing the refrigerant according to the required capacity to the operating indoor unit and flowing a small amount of the refrigerant to the non-operating indoor unit, Ensure the minimum refrigerant circulation required for operation.

[0010]

[0011]

[0012]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, A denotes one outdoor unit, and a plurality of indoor units B are connected to the outdoor unit A 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 fixed power compressor driven by a commercial power supply.

A high pressure side pipe 4 is connected to a discharge port of the compressor 1. A high pressure side pipe 4 is connected to a discharge port of the compressor 1 via a 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. Heating expansion valve 1 for check valve 9
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 lubricating oil contained in the refrigerant discharged from the compressors 1 and 2. An oil return pipe 16 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 pipe of a gas line between the check valve 9 and the liquid tank 10. The other end of the cooling bypass 17 is connected to a pipe of a low pressure line between the four-way valve 7 and the accumulator 14. Then, the opening degree variable valve 18 is connected to the cooling bypass 17.
Is provided.

A high pressure switch 21 and a refrigerant temperature sensor 25 are connected to a pipe extending from the discharge port of the compressor 1 to the high pressure 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 operate when the pressure of the refrigerant abnormally increases and reaches a predetermined value.

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

Between the dryer 11 and the strainer 15,
Strainer 31 and flow regulating valve 32 of indoor unit B
Is connected to the indoor heat exchanger 33 via the. Indoor heat exchanger 3
3, an indoor fan 34 is provided. And PMV3
The refrigerant pressure sensor 35 and the refrigerant temperature sensor 37 are attached to the pipe of the liquid line between the second heat exchanger 33 and the indoor heat exchanger 33. A refrigerant pressure sensor 36 and a refrigerant temperature sensor 38 are attached to a pipe of a 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 a pipe connection, the outdoor unit A and each indoor unit B constitute a heat pump refrigeration cycle. At the time of cooling, the four-way valve 7 is set to the neutral state, whereby the refrigerant discharged from the compressors 1 and 2 is caused to flow in the direction of the solid 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. At the time of 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 dashed arrow in the drawing to form a heating cycle, and the indoor heat exchangers 33 are used as condensers and outdoor heat exchangers. The vessel 8 functions as an evaporator.

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

FIG. 2 shows the control circuit. The outdoor unit A includes an outdoor control unit 50. The indoor control unit 60 of each indoor unit B is connected to the outdoor control unit 50 by wiring.

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, PMV18, 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
And the switch 53 are connected.

The inverter 52 rectifies the voltage of the AC power supply line in the outdoor control unit 50, converts the rectified voltage into a voltage of a predetermined frequency by switching according to a command from the outdoor control unit 50, and outputs the voltage. This output is the driving 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 an AC power supply line in the outdoor control unit 50 via a switch 53. The indoor control unit 60 comprises 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 a remote control) 61.
Connect.

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

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

[3] Means for controlling the opening of the PMV 32 according to the required capacity of the indoor unit. [4] 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 detection pressure (evaporation pressure) P _{c2 of the} refrigerant pressure sensor 36
Means for detecting the degree of superheating of the refrigerant in the indoor heat exchanger 33 from.

[6] During heating, the detected temperature (condenser outlet temperature) T _{c1 of the} refrigerant temperature sensor 37 attached to the liquid line and the detected pressure (condensation pressure) P _{c1 of the} refrigerant pressure sensor 35 are used to calculate the heat exchanger in the cold room. Means for detecting the degree of supercooling of the refrigerant in 33.

[7] 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 units.

[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 in accordance with the total required capacity of the indoor units 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 supplied to the four-way valve 7, the outdoor heat exchanger 8, each flow regulating valve 32, each indoor heat exchanger 33, and the four-way valve. 7
Means for returning to the compressors 1 and 2 to perform a 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 regulating valve 32, the outdoor heat exchanger 8, and the four-way valve 7. Compressor 1,
Means for returning to 2 and performing a heating operation.

[4] Means for executing a defrosting operation on the outdoor heat exchanger 8 in accordance with the detected temperature Te of the heat exchanger temperature sensor 28 during heating. [5] Detected pressure Pd of refrigerant pressure sensor 23 abnormally rises and set value (lower than operating point of high pressure switches 21 and 22)
, A 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 operates, and stopping the operation of the compressor 2 when the high-pressure switch 22 operates. [7] Detection temperature of refrigerant temperature sensor 25 (discharge refrigerant temperature)
When one of T _d1 and the detection temperature (discharge refrigerant temperature) T _d2 of the refrigerant temperature sensor 26 rises to the set value Tdx,
Means for opening the PMV 18 of the cooling bypass 17 and controlling the opening degree according to the higher one of T _d1 and T _d2 .

[8] When the total value of the capacity of the indoor unit issuing the operation request is equal to or less than the set value, the PMV 32 corresponding to the indoor unit issuing the operation request is opened to an opening corresponding to the required capacity. In addition, for indoor units or indoor temperature control in stop mode where no operation request is issued
PMV32 corresponding to the thermo-off indoor unit based
Means to open by a predetermined opening. The set value corresponds to the minimum refrigerant circulation amount necessary for operation of the outdoor unit A.

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

In an arbitrary indoor unit B, a user sets a desired operation mode and a desired indoor temperature (hereinafter, referred to as a set temperature) Ts by using the remote controller 61. Further, a driving start 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 to the neutral state, and the refrigerant flows in the direction of the solid arrow in FIG. 1 to form a cooling cycle. 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 a 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 detected temperature (intake air temperature) Ta of the indoor temperature sensor 39 and the temperature Ts set by the remote controller 61, and sends the required capacity corresponding to the temperature difference ΔT to the outdoor unit A. Inform. Furthermore, PMV
The opening 32 is set to an opening corresponding to the temperature difference ΔT.

When starting the compressors 1 and 2, the outdoor unit A determines its operating capacity (the number of operating compressors 1 and 2 and the operating frequency F of the compressor 1) by the sum of the required capacity from each indoor unit B. Set the operation capacity according to.

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

In the indoor unit B, the indoor heat exchange is performed based on the detected temperature (evaporator outlet temperature) T _c2 of the refrigerant temperature sensor 38 and the detected pressure (evaporation pressure) P _{c2 of the} refrigerant pressure sensor 36 in the gas line during cooling. The degree of superheat of the refrigerant in the heater 33 is detected. At the time of heating, the degree of supercooling of the refrigerant in the heat exchanger 33 in the cold room is determined from the detected temperature (condenser outlet temperature) T _c1 of the refrigerant temperature sensor 37 and the detected pressure (condensation pressure) P _{c1 of the} refrigerant pressure sensor 35 in the liquid line. Is detected.
Then, the opening 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 rises abnormally, and the set value (the high-pressure switch 21,
22 (lower than the operating point of 22), the capacity of the compressor 1 (operating frequency F) is reduced by a predetermined value. This capacity reduction prevents the high pressure side pressure Pd from abnormally rising, and the compressor 1
2 and other refrigeration cycle equipment.

However, despite the capacity reduction, if the high pressure switch 21 is operated after the abnormal increase of the high pressure, the operation of the compressor 1 is stopped. When the high-pressure switch 22 operates, the operation of the compressor 2 is stopped. By stopping the operation, the refrigeration cycle equipment is reliably protected.

As for the low pressure side, the low pressure side pressure Ps is detected by the refrigerant pressure sensor 24. When the low pressure side pressure Ps abnormally rises and becomes a predetermined value or more, the capacity (operating frequency F) of the compressor 1 is reduced. Reduce by a predetermined value.

In the outdoor unit A, the refrigerant temperature sensor 25 detects the discharge refrigerant temperature T _d1 of the compressor 1, and the refrigerant temperature sensor 26 detects the discharge 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 of the detected temperatures T _d1 and T _d2 .

When the PMV 18 is opened in this way, a part of the liquid refrigerant flowing through the liquid line is partially cooled.
Through the compressors 1 and 2 into the suction side. The temperature of the flowing liquid refrigerant is low, so that a cooling action for the compressors 1 and 2 works, and an abnormal rise in the discharge refrigerant temperature or the suction refrigerant temperature is suppressed. Therefore, the control of the cooling bypass also protects the refrigeration cycle equipment.

During heating, frost gradually forms on the outdoor heat exchanger 8 as the operation proceeds, and the amount of heat exchange is reduced as it is, resulting in insufficient heating capacity. Therefore, the outdoor heat exchanger 8 is detected by the heat exchanger temperature sensor 28.
Is detected, and when the detected temperature Te falls below a set value, for example, 0 ° C. or less, 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 discharged from the compressors 1 and 2 (high-temperature refrigerant) is supplied to the outdoor heat exchanger 8. . By the supply of the high-temperature refrigerant, the frost adhering to the outdoor heat exchanger 8 is melted.

When the defrosting progresses and the detected temperature Te of 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 hp, the minimum amount of refrigerant circulating required for the operation of the outdoor unit A is 2.0 hp (= set value), and the capacity of each indoor unit B is as shown in the example of FIG.
1.0 horsepower and 0.15 horsepower are mixed.

In this case, two of the indoor units B of 1.0 hp
Assuming that the unit has issued an operation request, its total capacity is
Since it is 2.0 hp, which satisfies the set value of 2.0 hp based on the required minimum refrigerant circulation amount of the outdoor unit A, normal operation is performed.

That is, in the normal operation, the opening of the PMV 32 corresponding to the indoor unit B issuing the operation request is set to an opening corresponding to the required capacity of each indoor unit B. For the indoor unit B that has not issued an operation request, the corresponding PMV 32 is fully closed. Also, the indoor unit B that has issued the operation request and is actually in the operation mode, closes the corresponding PMV 32 completely when the intake air temperature Ta reaches the set temperature Ts and the required capacity becomes zero, and performs indoor heat exchange. The flow of the refrigerant into the heater 33 is stopped, and the operation is interrupted. That is, the thermo-off is performed based on the indoor temperature control.

The indoor unit B in the operation mode responds to the user's operation to stop the operation of the
Is fully closed to enter the stop mode. It is also assumed that one indoor unit B has issued 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 capacity is 1.0 horsepower or 0.15 horsepower and does not satisfy the set value of 2.0 horsepower, the PMVs 32 corresponding to the indoor unit B in the stop mode and the indoor unit B in the thermo-off mode are respectively opened by a predetermined opening.

In this way, when the PMV 32 is opened by a predetermined opening, a small amount of refrigerant flows through the indoor unit B in the stop mode and the indoor unit B in the thermo-off mode, and the minimum amount of refrigerant circulating 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 amount of refrigerant circulating in the outdoor unit A, such as a personal air conditioning unit for individuals, can be connected. Variations can be expanded.

In the above-described embodiment, the PMV 32 corresponding to the indoor unit B in the stop mode and the thermo-off is opened by a predetermined opening. However, 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. FIG.
As shown in the flowchart, the PMV 32 corresponding to only the thermo-off indoor unit B may be opened by a predetermined opening.

[0060]

As described above, the air conditioner of the present invention
When the total value of the capacity of the indoor unit requiring the operation is equal to or less than the set value corresponding to the minimum refrigerant circulation amount required for the operation of the outdoor unit, the flow control valve corresponding to the indoor unit requiring the operation is provided. The opening of the indoor unit in the stop mode that does not require operation
Open the flow control valve corresponding to the thermo-off indoor unit based on the temperature control or the indoor temperature control by a predetermined opening, and flow the refrigerant according to the required capacity to the operating indoor unit and flow a small amount of refrigerant to the non-operating indoor unit. Since the minimum amount of refrigerant circulating required for the operation of the outdoor unit is ensured, the indoor unit of any capacity can be connected to the outdoor unit, and the connection variation can be expanded. In addition, the driver cabin unit
Flow the amount of refrigerant in accordance with the
Operate the outdoor unit by flowing a small amount of refrigerant through the knit
The minimum required amount of refrigerant circulation for
The forced operation of the non-operating cabin unit
Compared to those that secure the required amount of refrigerant circulation for the outer unit
To operate outdoor units without compromising comfort
Without increasing the required amount of refrigerant circulation more than necessary,
It will save energy.

[Brief description of the drawings]

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

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

FIG. 3 is a view showing an example of a connection variation according to the embodiment.

FIG. 4 is a view showing an example of a connection variation according to the embodiment.

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

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

FIG. 7 is a flowchart for explaining the operation of a modification of the 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 control valve), 33: indoor heat exchanger, 50: outdoor control unit, 60: indoor control unit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 13/00 F24F 11/02 102 F25B 5/02 510

Claims (1)

(57) [Claims] An outdoor unit having a compressor and an outdoor heat exchanger; a plurality of indoor units each having a flow control valve and an indoor heat exchanger; the compressor, the outdoor heat exchanger, each flow control valve; A refrigeration cycle to which each indoor heat exchanger is connected; a means for controlling the capacity of the compressor in accordance with the required capacity of each indoor unit; and an opening degree of each flow regulating valve in accordance with the required capacity of each indoor unit. Control means, and when the total value of the capacity of the indoor unit requiring the operation is equal to or less than the set value corresponding to the minimum refrigerant circulation amount required for the operation of the outdoor unit, the flow rate corresponding to the indoor unit requiring the operation There is a stop mode indoor unit that opens the regulating valve to the opening corresponding to the required capacity and does not require operation.
Or means for opening a flow control valve corresponding to a thermo-off indoor unit based on indoor temperature control by a predetermined opening degree ,
When the refrigerant according to the required capacity flows into the cab unit,
In both cases, a small amount of refrigerant flows through the non-cabin unit
The minimum amount of refrigerant circulating required for the operation of the outdoor unit.
An air conditioner characterized by securing .