JPH0642831A - Air conditioner - Google Patents

Abstract

PURPOSE:To enable refrigerant to be recovered without generating any cooled air feeling in a room by a method wherein an operation of a refrigerant heater is stopped while an operation of a compressor is continued during a heating operation and then refrigerant stored at an outdoor heat exchanger is recovered with suction pressure of the compressor. CONSTITUTION:If a sensed temperature of an indoor temperature sensor is lower than a set indoor temperature, a compressor 1 is excited to start while a two-way valve 8 is being opened, a four-way valve 2 is changed over and a refrigerant heater 9 is turned on (a gas burner 10 is ignited). Then, refrigerant flows to form a heating cycle, an indoor heat exchanger 6 is operated as a condensor, a refrigerant heater 9 is operated as an evaporator and then hot air is blown into a room. Refrigerant is recovered in such a manner that the operation of the refrigerant heater 9 is stopped while the operation of the compressor 1 is being continued and then a two-way valve 8 is closed for a predetermined period of time and refrigerant stored in the outdoor heat exchanger 3 is recovered with suction pressure of the compressor 1. With such an arrangement refrigerant can be recovered without giving any cooled air feeling within the room.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner equipped with a refrigerant heater.

[0002]

2. Description of the Related Art In some air conditioners, a heat pump type refrigeration cycle is provided with a refrigerant heater and the combustion heat of the refrigerant heater is used to heat a room.

That is, when heating the room, the refrigerant discharged from the compressor is caused to flow through the four-way valve, the indoor heat exchanger, the pressure reducer and the refrigerant heater, and the refrigerant heater is turned on to turn on the indoor heat exchanger. Use the condenser and refrigerant heater as an evaporator.

However, at the start of the heating operation, the refrigerant flow to the refrigerant heater is shut off for a predetermined time, the refrigerant heater is kept off, and the refrigerant accumulated in the outdoor heat exchanger (compressor lubrication). (Including oil) is collected on the compressor side by the suction pressure of the compressor. This prevents the refrigerant circulation amount in the refrigeration cycle from becoming insufficient. This is because the shortage of the circulation amount of the refrigerant causes an abnormal increase in the pressure on the high-pressure side, and eventually causes an unnecessary operation stop due to the function of the high-pressure protection.

In such an air conditioner, the check valve blocks the inflow of the refrigerant into the outdoor heat exchanger during operation, but the outdoor heat exchanger is passed through the check valve and the four-way valve. The refrigerant may leak to the side. In this case, as the operation progresses, the refrigerant accumulates in the outdoor heat exchanger, and eventually the refrigerant circulation amount becomes insufficient. Therefore,
Some refrigerants are collected not only at the start of heating operation but also during operation as needed.

Refrigerant recovery during this operation is performed by turning off the operation of the refrigerant heater and turning off the operation of the compressor while maintaining the switching state of the four-way valve and the refrigerant flow to the refrigerant heater. The pressure balance is ensured, the compressor is thereafter turned on, the refrigerant flow to the refrigerant heater is shut off, and the refrigerant accumulated in the outdoor heat exchanger is taken in by the suction pressure of the compressor. On the other hand, as an air conditioner equipped with a refrigerant heater, there is a multi-type that has a plurality of indoor units and the indoor heat exchangers of the indoor units are connected in parallel with each other.

In this multi-type air conditioner, when at least one of the indoor units is stopped during heating operation, the refrigerant is continuously circulated to the stopped indoor unit for a certain period of time, and the refrigerant is accumulated in the stopped indoor unit. The refrigerant is taken into the suction side of the compressor by so-called refrigerant blow.

Further, in the multi-type air conditioner, the required operation mode of each indoor unit may be different between cooling and heating. In that case, heating operation is preferentially executed and a request other than heating is requested. For indoor units, it is common to stop the operation and blow only air.

[0009]

By the way, in an air conditioner that secures a pressure balance before the recovery of the refrigerant, the pressure balance takes about 2 to 3 minutes, so that the room temperature decreases during that time. There is the problem of giving a cold sensation to the room.

On the other hand, in the multi-type air conditioner, the capacity of the compressor is usually determined so that a sufficient amount of blown refrigerant can be obtained even when the temperature of the indoor heat exchanger on the operating side is low during refrigerant recovery. However, conversely, in the condition that the temperature of the indoor heat exchanger on the operating side is high, the refrigerant circulation amount in the entire refrigeration cycle tends to be excessive, the high-pressure side pressure rises abnormally, and the high-pressure protection function causes the operation to stop. Sometimes.

Further, in the multi-type air conditioner, when the required operation mode of the indoor unit is changed to cooling during the heating operation, the heating operation is stopped in the indoor unit and air blowing is started. At this time, the refrigerant for refrigerant recovery circulates through the indoor unit in the air-blowing state, but the circulating refrigerant condenses due to the air-blowing action, which not only makes it difficult to recover the refrigerant, but also promotes the shortage of the refrigerant. .

Further, in the multi-type air conditioner,
Although the circulation of the refrigerant for the refrigerant recovery is performed for a certain period of time, the maximum time that seems to be necessary for the refrigerant recovery is set for the certain period of time, so even if the refrigerant recovery has already been completed in some cases. Regardless, the circulation of the refrigerant continues, which may lead to deterioration of operating efficiency. The present invention takes the above circumstances into consideration, and an object of the air conditioner of claim 1 is to make it possible to recover the refrigerant without giving a cold air feeling to the room.

An air conditioner according to a second aspect of the present invention has an object of enabling reliable refrigerant recovery without causing an abnormal increase in the pressure on the high-pressure side and without causing an unnecessary operation stop of the compressor. An air conditioner according to a third aspect of the present invention is intended to enable reliable refrigerant recovery without causing a shortage of refrigerant. An air conditioner according to a fourth aspect of the present invention is capable of setting the time for circulating the refrigerant in an appropriate state and improving the operating efficiency.

[0014]

An air conditioner according to claim 1 is a heat pump type refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducer, and an indoor heat exchanger communicate with each other, and the outdoor. A refrigerant heater provided so as to communicate from the communication part of the heat exchanger and the pressure reducer to the suction port of the compressor, and a four-way valve for discharging the refrigerant discharged from the compressor, an indoor heat exchanger, a pressure reducer, and a refrigerant heater. And a means for performing a heating operation by turning on the refrigerant heater and turning on the refrigerant heater, and during the heating operation, the operation of the refrigerant heater is stopped while the operation of the compressor is continued, and the refrigerant is collected in the outdoor heat exchanger. Means for recovering the refrigerant by the suction pressure of the compressor.

An air conditioner according to a second aspect of the present invention includes an outdoor unit having a compressor and an outdoor heat exchanger, and a plurality of indoor units each having an indoor heat exchanger, and enables air cooling and heating operations. In the harmony machine, during heating operation,
When at least one of the indoor units is shut down, a means for carrying out the refrigerant recovery by continuing the circulation of the refrigerant to the stopped indoor unit for a certain time, and the indoor heat of the driving indoor unit at the time of the refrigerant recovery. And a means for controlling the capacity of the compressor according to the temperature of the exchanger, the temperature of the refrigerant flowing out of the indoor heat exchanger, or the temperature of the refrigerant flowing out of the indoor heat exchangers and joining. .

An air conditioner according to a third aspect of the invention includes an outdoor unit having a compressor and an outdoor heat exchanger, and a plurality of indoor units each having an indoor heat exchanger, and enables air cooling and heating operations. In the harmony machine, when the required operation mode of each indoor unit is different, the heating operation is preferentially executed, and for the indoor unit requesting other than heating, means for stopping operation and performing only blowing, and during heating operation, When at least one of the indoor units is shut down, a means for carrying out the refrigerant recovery by continuing the circulation of the refrigerant to the stopped indoor unit for a certain period of time, and a ventilation of the stopped indoor unit at the time of this refrigerant recovery. And means for prohibiting.

An air conditioner according to a fourth aspect of the present invention comprises an outdoor unit having a compressor and an outdoor heat exchanger, and a plurality of indoor units each having an indoor heat exchanger, and enables air cooling and heating operations. In the harmony machine, during heating operation,
When the number of operating each of the indoor units is changed, a means for carrying out refrigerant recovery by continuing the circulation of the refrigerant to the indoor unit whose operation is stopped or the indoor unit on the low capacity side for a predetermined time, and the predetermined time during which the indoor operation is stopped. The unit or the low capacity side indoor unit is provided with means for varying the temperature of the indoor heat exchanger and the temperature of the refrigerant flowing out from the indoor heat exchanger.

[0018]

In the air conditioner of claim 1, during the heating operation, the operation of the refrigerant heater is stopped while the operation of the compressor is continued, and the refrigerant accumulated in the outdoor heat exchanger by the suction pressure of the compressor is removed. to recover.

In the air conditioner of claim 2, during heating operation,
When the operation of at least one of the indoor units is stopped, the flow of the refrigerant to the stopped indoor unit is continued for a certain period of time to perform the refrigerant recovery. At the time of this refrigerant recovery, compression is performed according to the temperature of the indoor heat exchanger of the indoor unit, the temperature of the refrigerant flowing out of the indoor heat exchanger, or the temperature of the refrigerant flowing out of the indoor heat exchangers and joining. Control the capacity of the machine.

In the air conditioner of claim 3, during heating operation,
When the operation of at least one of the indoor units is stopped, the flow of the refrigerant to the stopped indoor unit is continued for a certain period of time to perform the refrigerant recovery. At the time of this refrigerant recovery, the ventilation of the stopped indoor unit is prohibited.

In the air conditioner of claim 4, during heating operation,
When the number of operating indoor units changes, the flow of the refrigerant to the indoor units whose operation has stopped or to the indoor units on the low capacity side is continued for a predetermined time to execute the refrigerant recovery. The predetermined time for this refrigerant recovery is varied according to the difference between the temperature of the indoor heat exchanger of the stopped indoor unit or the low capacity side indoor unit and the temperature of the refrigerant flowing out from the indoor heat exchanger.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. The first embodiment corresponds to the air conditioner of claim 1.

As shown in FIG. 2, a variable capacity compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a check valve 4 (forward direction), a pressure reducer such as an electric expansion valve 5, an indoor heat exchanger 6, The four-way valve 2 and the check valve 7 (forward direction) are sequentially connected to form a heat pump type refrigeration cycle. The two-way valve 8 and the refrigerant heater 9 are sequentially connected from the communication portion between the check valve 4 and the expansion valve 5 to the suction port of the compressor 1. The refrigerant heater 9 is equipped with a gas burner 10 as an accessory.
Is connected to a fuel supply source (not shown) via a proportional valve 11. An outdoor fan 12 is provided near the outdoor heat exchanger 3, and an indoor fan 13 is provided near the indoor heat exchanger 6.
In the refrigerant pipe between the check valve 4 and the electric expansion valve 5,
The first refrigerant temperature sensor 14 is attached to the electric expansion valve 5 side of the connection portion of the electromagnetic opening / closing valve 8. The second refrigerant temperature sensor 15 is attached to the refrigerant pipe on the outlet side of the refrigerant heater 9.

The variable capacity compressor 1, four-way valve 2, outdoor heat exchanger 3, check valve 4, electric expansion valve 5, check valve 7, two-way valve 8, refrigerant heater 9 (burner 10 and The outdoor unit A includes the proportional valve 11, the outdoor fan 12, the first refrigerant temperature sensor 14, the second refrigerant temperature sensor 15, and the like. Further, at least the indoor heat exchanger 6 and the indoor fan 13 form an indoor unit B. The control circuit is shown in FIG. The outdoor control unit 20 of the outdoor unit A is connected to the commercial AC power supply 21.

The outdoor controller 20 comprises a microcomputer and its peripheral circuits. In this outdoor control unit 20,
The four-way valve 2, the electronic expansion valve 5, the two-way valve 8, the proportional valve 11, the indoor fan motor 12M, the refrigerant temperature sensors 14 and 15, and the inverter circuit 22 are connected.

The inverter circuit 22 rectifies the voltage of the power supply 21 and converts it into an AC voltage of a predetermined frequency by switching according to a command from the outdoor control unit 20. This output is supplied to the compressor motor 1M as drive power.

The indoor control unit 23 of the indoor unit B is connected to the outdoor control unit 20 via the power supply line ACL and the serial signal line SL. The serial signal line SL is
This is for performing data transfer between the control units in synchronization with the power supply voltage.

The indoor controller 23 comprises a microcomputer and its peripheral circuits. In this indoor control unit 23,
An indoor fan motor 13M, an indoor temperature sensor 24, and a remote control type operation device (hereinafter, abbreviated as a remote controller) 25 are connected. And the outdoor control part 20 and the indoor control part 23 are provided with the following functional means.

(1) The compressor 1 is turned on, the four-way valve 2 is not switched, the two-way valve 8 is closed, and the refrigerant heater 9 is turned off to set the refrigerant discharged from the compressor 1 in four directions. The refrigerant flows through the valve 2, the outdoor heat exchanger 3, the check valve 4, and the electric expansion valve 5 to the indoor heat exchanger 6, and the refrigerant passing through the indoor heat exchanger 6 passes through the four-way valve 2 and the check valve 7 to the compressor 1 The means for performing the cooling operation.

(2) During the cooling operation, the difference between the detected temperature of the indoor temperature sensor 41 and the set temperature of the remote controller 43 is obtained, and the operating frequency of the compressor 1 (the inverter circuit 5
Output frequency of 1).

(3) The compressor 1 is turned on, the four-way valve 2 is switched, the two-way valve 8 is opened, and the refrigerant heater 9 is turned on (combustion of the gas burner 10). The refrigerant flowing through the four-way valve 2, the indoor heat exchanger 6, the outside heat exchanger 3, the check valve 4, the electrically driven expansion valve 5, and the two-way valve 8 to the refrigerant heater 9, and the refrigerant passing through the refrigerant heater 9 Is returned to the compressor 1 through the four-way valve 2 to perform heating operation.

(4) During heating operation, the difference between the temperature detected by the remote controller 43 and the temperature detected by the indoor temperature sensor 41 is obtained as a heating load, and the operating frequency of the compressor 1 (output of the inverter circuit 51 is determined according to the heating load. Frequency) control means.

(5) During heating operation, the second refrigerant temperature sensor 1
Calculation means for calculating a difference ΔT (= T ₂ −T ₁ ) between the detected temperature T _{2 of} No. 5 and the detected temperature T 1 of the first refrigerant temperature sensor 14. (6) Means for controlling the opening degree of the electrically driven expansion valve 5 during the heating operation so that the calculated temperature difference ΔT, that is, the refrigerant superheat degree becomes constant at the set value ΔTsa (5 to 8 deg).

(7) Second heating temperature sensor 1 during heating operation
A means for reducing the opening amount of the proportional valve 11 and decreasing the heating amount of the refrigerant heater 9 (combustion amount of the gas burner 10) when the detected temperature T _{2 of} 5 exceeds the set value Teo for preventing overheating.

(8) During heating operation, the temperature difference ΔT is set in advance in the zone A (ΔTs ₂ ) of the heating amount control condition (FIG. 4).
Below), means for adjusting the opening of the proportional valve 11 (corresponding to the heating amount of the refrigerant heater 9) according to the heating load. (9) When the temperature difference ΔT rises to the B zone (ΔTs ₂ or more) of the heating amount control condition during the heating operation, the proportional valve 11
Means to reduce the opening degree of.

(10) During heating operation, the temperature difference ΔT is C zone (ΔTs ₂ or less, ΔTs ₁ or more) under the above heating amount control condition.
A means for holding the opening of the proportional valve 11 as it is when it is lowered to. (12) Counting means for counting the number of times the temperature difference ΔT exceeds the set value ΔTs ₂ during the heating operation. (13) A means for recovering the refrigerant accumulated on the outdoor heat exchanger 3 side when the count value N of the counting means reaches a predetermined value Ns (for example, "10") during the heating operation.

(14) During heating operation, the temperature difference ΔT is the set value Δ
The time t exceeding Ts ₂ is integrated, and the integrated time ta
Means for recovering the refrigerant accumulated on the outdoor heat exchanger 3 side when reaches a predetermined value ts.

(15) During the heating operation, the operation of the refrigerant heater 9 is stopped while the operation of the compressor 1 is continued (the gas burner 10
(Combustion stop), the refrigerant collected in the outdoor heat exchanger 3 is recovered by the suction pressure of the compressor 1. Next, the operation will be described with reference to FIGS. When the desired room temperature is set by the remote controller 25 and the heating operation is started, first the room temperature sensor 2
The detected temperature of 4 and the set room temperature are compared.

If the temperature detected by the room temperature sensor 24 is lower than the set room temperature, the compressor 1 is opened with the two-way valve 8 open.
Is started, the four-way valve 2 is switched, and the refrigerant heater 9 is turned on (the gas burner 10 is burned).

Then, the refrigerant flows in the direction of the broken line arrow in FIG. 2 to form a heating cycle, the indoor heat exchanger 6 functions as a condenser and the refrigerant heater 9 functions as an evaporator, and hot air is blown out into the room. .

During this heating operation, the difference between the set room temperature based on the operation of the remote controller 25 and the temperature detected by the room temperature sensor 24 is obtained as a heating load, and the operating frequency F of the compressor 1 is controlled according to the heating load. .

During the heating operation, the temperature T ₁ detected by the temperature sensor 14 (the temperature of the refrigerant flowing into the refrigerant heater 9 through the expansion valve 5) is taken in, and the temperature T detected by the temperature sensor 15 is taken in.
₂ (the temperature of the refrigerant flowing out of the refrigerant heater 9) is taken in,
The difference ΔT (= T ₂ −T ₁ ) between the two detected temperatures is calculated. This temperature difference ΔT corresponds to the degree of refrigerant superheat in the refrigerant heater 9.

Then, the opening degree of the electric expansion valve 5 is controlled so that the temperature difference ΔT becomes constant at the set value Tsa. With this constant control, the operation of the refrigeration cycle is stabilized, and the effect that the heating capacity rises quickly can be obtained.

Further, the temperature difference ΔT is compared with the heating amount control condition of FIG. 4, and the temperature difference ΔT is set to the set value Ts ₂ (for example, 26
If the temperature is in the zone A below (° C), the opening of the proportional valve 11 is adjusted according to the heating load, and the heating amount of the refrigerant heater 9 (combustion amount of the gas burner 10) is controlled. By the way, during operation, the refrigerant may leak to the outdoor heat exchanger 3 side through the four-way valve 2 and the check valves 4 and 7. If the refrigerant leaks to the outdoor heat exchanger 3 side, the circulation amount of the refrigerant passing through the refrigerant heater 9 decreases,
The temperature difference ΔT increases. .

When the temperature difference ΔT increases, the opening degree of the electric expansion valve 5 increases accordingly. However, when the refrigerant circulation amount exceeds the reduction limit, the electric expansion valve 5 is fully opened, and if it exceeds the limit. The increase in the temperature difference ΔT cannot be suppressed. When the temperature difference ΔT enters the B zone where the temperature difference ΔT is equal to or larger than the set value Ts ₂ without suppressing the increase, the opening degree of the proportional valve 11 is decreased. When the opening degree of the proportional valve 11 decreases, the heating amount of the refrigerant heater 9 decreases and the temperature difference ΔT decreases.

When the temperature difference ΔT is equal to or less than ΔTs ₂ and enters the C zone of ΔTs ₁ (for example, 24 ° C.) or more, the opening degree of the proportional valve 11, that is, the heating amount of the refrigerant heater 9 is maintained as it is.

Here, when the temperature difference ΔT enters the B zone, the control units 20 and 23 set the internal flag f to "1". Further, the control units 20 and 23 start the time count t by the internal timer, and the time count t
Is integrated as ta.

When the temperature difference ΔT enters the A zone, it is determined whether or not the flag f is "1". If it is "1", that is, after the heating amount is reduced by the B zone, the control unit 20. , 23 increments the count N by the internal counter by "1" and returns the flag f to "0".

Thus, the count value N is the predetermined value Ns.
(For example, "10") or the total time t
When a reaches a predetermined value ts, the refrigerant accumulated on the outdoor heat exchanger 3 side is recovered.

In this refrigerant recovery, the operation of the refrigerant heater 9 is first stopped (the combustion of the gas burner 10 is stopped) while the operation of the compressor 1 is continued, and then the two-way valve 8 is closed for a predetermined time. The refrigerant (including the lubricating oil of the compressor 1) accumulated in the outdoor heat exchanger 3 is recovered to the compressor 1 side by the suction pressure of the compressor 1.

By recovering the refrigerant accumulated on the outdoor heat exchanger 3 side in this manner, the shortage of the refrigerant circulation amount can be immediately solved, and the abnormal increase in the high-pressure side pressure, and thus the unnecessary operation stop due to the high-pressure protection. Can be prevented.

Moreover, whether or not to carry out the refrigerant recovery is determined on the basis of the number N of times when the degree of refrigerant superheat exceeds the set value or the time ta when the degree of refrigerant superheat exceeds the set value, so that the shortage of the refrigerant circulation amount can be accurately grasped. Therefore, the refrigerant recovery can always be executed at the optimum timing. In particular, since the refrigerant recovery is started while the compressor 1 is continuously operated and the conventional pressure balance is removed, a cold air feeling is not given to the room.

When the temperature detected by the room temperature sensor 24 reaches the set room temperature, the compressor 1 and the refrigerant heater 9 are turned off and the heating operation is interrupted. At this time, the flag F, the number of times count N, and the integration time ta are each cleared. When the operation is stopped by operating the remote control 25, the flag F, the number of times count N, and the integrated time ta are similarly cleared. Next, a second embodiment of the present invention will be described. The second embodiment corresponds to the air conditioner of claims 2 and 3. In FIG. 7, A is an outdoor unit, B ₁ and B ₂ are indoor units, and the next refrigeration cycle is configured between these units.

An outdoor heat exchanger 33 is connected to the discharge port of the compressor 31 via a four-way valve 32, and a forward check valve 34 and a pair of liquid pipes W ₁ , W ₂ are connected to the outdoor heat exchanger 33. The indoor heat exchangers 42 and 52 are connected via the.

Gas pipes G ₁ and G are attached to the indoor heat exchangers 42 and 52.
₂ , the accumulator 36 is connected through the four-way valve 32 and the check valve 35 in the forward direction, and the accumulator
The suction port of the compressor 31 is connected to the compressor 36. Electronic expansion valves 41 and 51 are provided in the liquid pipes W ₁ and W ₂ , respectively.
An electronic flow rate adjusting valve 37 is provided in communication between the gas pipes G ₁ and G ₂ . In the gas pipes G ₁ and G ₂ , two-way valves 43 and 53 are provided at positions closer to the four-way valve 32 than the communicating position of the flow rate adjusting valve 37.

From the communicating portion between the check valve 34 connected to the outdoor heat exchanger 33 and the electronic expansion valves 41, 51 to the accumulator 36 on the suction side of the compressor 31, the two-way valve 38 is used. The refrigerant heater 60 is provided so as to communicate with each other.

The refrigerant heater 60 includes a gas burner 61,
The gas burner 6 is equipped with a combustion fan 62, a proportional valve 63, an igniter 64 and a flame detector 65 which will be described later, and the like.
The refrigerant is heated by the combustion flame No. 1. An outdoor fan 39 is provided near the outdoor heat exchanger 33, and indoor fans 44 and 54 are provided near the indoor heat exchangers 42 and 52, respectively.
To provide. The heat exchanger temperature sensors 45 and 55 are attached to the indoor heat exchangers 42 and 52, respectively. Gas pipes G ₁ and G ₂
Refrigerant temperature sensors 46 and 56 are attached to the respective.

In the communication portion between the check valve 34 and the electronic expansion valves 41, 51, the refrigerant temperature sensor 71 is attached at a position slightly closer to the electronic expansion valves 41, 51 than the connecting portion of the system of the refrigerant heater 60. A refrigerant temperature sensor 72 is attached to the communication portion from the refrigerant heater 60 to the accumulator 36. The control circuit is shown in FIG. The outdoor control unit 80 of the outdoor unit A is connected to the commercial AC power supply 81.

The outdoor controller 80 comprises a microcomputer and its peripheral circuits. In this outdoor control unit 80,
Electronic expansion valves 41, 51, electronic flow rate adjusting valve 37, proportional valve 6
3, igniter 64, flame detector 65, combustion fan motor 62M, four-way valve 32, outdoor fan motor 39M, refrigerant temperature sensor 46, 56, 71, 72, two-way valve 43, 53,
38 and the inverter circuit 82 are connected.

The inverter circuit 82 rectifies the voltage of the power supply 81 and converts it into an AC voltage of a predetermined frequency by switching according to a command from the outdoor control unit 80. This output is supplied to the compressor motor 31M as drive power. The indoor units B ₁ and B ₂ each include an indoor control unit 90.

The indoor control unit 90 comprises a microcomputer and its peripheral circuits. In this indoor control unit 90,
Indoor temperature sensor 91, heat exchanger temperature sensor 45 (and 55), remote control type operation device (hereinafter abbreviated as remote controller) 92, and indoor fan motor 44M.
(And 54M) are connected. Then, each indoor control unit 9
0 is connected to the outdoor control unit 80 by the power supply line ACL and the serial signal line SL, respectively. Indoor control unit 90
Has the following functional means. (1) A means for sending an operation mode command or set room temperature data by operating the remote controller 92 to the outdoor control section 80 by a serial signal synchronized with the power supply voltage.

(2) The difference between the detected temperature of the indoor temperature sensor 91 and the set indoor temperature of the remote controller 92 (that is, the air-conditioning load) is detected, and the outdoor control section 80 uses the serial signal in synchronization with the power supply voltage as the required capacity. Means to send to. (3) A means for sending the temperature data detected by the heat exchanger temperature sensors 45, 55 to the outdoor controller 80 by a serial signal synchronized with the power supply voltage. The outdoor control unit 80 includes the following functional means.

(1) Based on the cooling operation mode command from the indoor units B ₁ and B ₂ , the refrigerant discharged from the compressor 31 is supplied with the four-way valve 32, the outdoor heat exchanger 33, the check valve 34, and the electronic expansion valve 41. , 51, indoor heat exchangers 42, 52, two-way valve 4
3, 53, a four-way valve 32, a check valve 35, an accumulator 36, and a means for performing a cooling operation. (2) During this cooling operation, the capacity of the compressor 31 (= the output frequency F of the inverter circuit 82) is set to the indoor units B ₁ , B ₂
A means for controlling according to the total sum of required capabilities of.

(3) During the cooling operation, of the two-way valves 43 and 53, the two-way valve corresponding to the one having the larger required capacity of the indoor units B ₁ and B ₂ is opened, and the two-way valve corresponding to the smaller one is opened. Means of closing.

(4) Indoor units B ₁ and B during cooling operation
Refrigerant evaporation temperature at ₂ (= heat exchanger temperature sensors 45, 55
Flow rate adjustment so that the difference (or ratio) between the detection temperatures Tc ₁ and Tc ₂ of the indoor units B ₁ and B ₂ has a predetermined relationship based on the required capacity of the indoor units B ₁ and B ₂ (= value corresponding to the ratio or difference of required capacity). A means for controlling the opening degree of the valve 37.

(5) During the cooling operation, the indoor heat exchangers 42, 5
A means for detecting the degree of refrigerant superheat at 2 (= difference between the temperature detected by the heat exchanger temperature sensors 45, 55 and the temperature detected by the refrigerant temperature sensors 46, 56). (6) A means for controlling the opening degree of the electronic expansion valves 41, 51 so that the detected refrigerant superheats have constant values.

(7) Based on the heating operation mode command from the indoor units B ₁ and B ₂ , the refrigerant discharged from the compressor 31 is supplied with the four-way valve 32, the two-way valves 43 and 53, and the indoor heat exchanger 4.
2, 52, electronic expansion valves 41, 51, two-way valve 38, refrigerant heater 60, accumulator 36, and means for causing heating operation.

(8) During this heating operation, the capacity of the compressor 31 (= output frequency F of the inverter circuit 82) and the heating amount of the refrigerant heater 60 (= combustion amount of the gas burner 61) are set to the indoor units B ₁ and B _2. A means for controlling according to the total sum of required capabilities of.

(9) During the heating operation, of the two-way valves 43 and 53, the two-way valve corresponding to the one having a larger required capacity of the indoor units B ₁ and B ₂ is opened, and the two-way valve corresponding to the smaller one is opened. Means of closing.

(10) Indoor heating exchangers 42, 5 during heating operation
The temperature of the refrigerant flowing into 2 (= refrigerant temperature sensors 46, 56
Flow rate adjustment so that the difference (or ratio) between the detection temperatures Tg ₁ and Tg ₂ of the indoor units B ₁ and B ₂ has a predetermined relationship (= value corresponding to the ratio or difference of required capacities). A means for controlling the opening degree of the valve 37. (11) Refrigerant superheat degree in the refrigerant heater 60 (=
A means for detecting the difference between the temperature detected by the refrigerant temperature sensor 71 and the temperature detected by the refrigerant temperature sensor 72. (12) Means for simultaneously controlling the opening amounts of the electronic expansion valves 41 and 51 by the same amount so that the detected refrigerant superheat degree becomes a constant value.

(13) During heating operation, the indoor units B ₁ , B
Upon at least one shutdown of the _two, means for performing a refrigerant recovery to continue the flow of refrigerant to the stop the indoor unit by a predetermined time. (14) A means for controlling the capacity of the compressor 31 in accordance with the temperature of the indoor heat exchanger of the driver's indoor unit during the recovery of the refrigerant. (15) A means for prohibiting ventilation of the stopped indoor unit at the time of refrigerant recovery. Next, the operation of the above configuration will be described. First, the overall operation will be described with reference to FIGS. 9 and 10.

It is assumed that the cooling operation mode and the desired indoor temperature are set by the remote controller 92 of the indoor unit B ₁ and the operation start operation is performed. The operation of the indoor unit B ₂ is stopped. In this case, the two-way valve 43 on the driving side
Open and close the two-way valve 53 on the stop side. Further, the flow rate adjusting valve 37 is fully closed.

Then, the compressor 31 is started, and the compressor 31
The refrigerant discharged from the four-way valve 3 as shown by the solid line arrow in FIG.
2, outdoor heat exchanger 33, electronic expansion valve 41, indoor heat exchanger 52, two-way valve 43, four-way valve 32, check valve 35, accu
It flows through the mullet 36 to start the independent cooling operation of the indoor unit B ₁ .

In this cooling alone operation, the capacity of the compressor 31 (= output frequency F of the inverter circuit 82) is controlled according to the required capacity of the indoor unit B ₁ . Further, the degree of refrigerant superheat in the indoor heat exchanger 42 (= the difference between the temperature detected by the heat exchanger temperature sensor 45 and the temperature detected by the refrigerant temperature sensor 46) is detected so that the detected degree of refrigerant superheat becomes a constant value. The opening degree of the electronic expansion valve 41 is controlled.

It is also assumed that the heating operation mode and the desired indoor temperature are set by the remote controller 92 of the indoor unit B ₁ and the operation start operation is performed. The indoor unit B
_{No. 2} will be stopped. In this case, the two-way valve 43 on the driving side is opened and the two-way valve 53 on the stop side is closed. further,
The flow rate adjusting valve 37 is fully closed.

Then, the compressor 31 is started, and the compressor 31
The refrigerant discharged from the four-way valve 3 as shown by the broken line arrow in FIG.
2, two-way valve 43, indoor heat exchanger 42, electronic expansion valve 41,
It flows through the two-way valve 38, the refrigerant heater 60, and the accumulator 36 to start the independent heating operation of the indoor unit B ₁ .

During this heating only operation, the capacity of the compressor 31 (= output frequency F of the inverter circuit 82) and the heating amount of the refrigerant heater 60 (= combustion amount of the gas burner 61) are set according to the required capacity of the indoor unit B _1. Control. Further, the degree of refrigerant superheat in the refrigerant heater 60 (= the difference between the temperature detected by the refrigerant temperature sensor 71 and the temperature detected by the refrigerant temperature sensor 72) is detected, and the electronic expansion valve is set so that the detected degree of refrigerant superheat becomes a constant value. The opening degree of 41 is controlled. On the other hand, the indoor units B ₁ , B
It is assumed that the cooling operation mode and the desired room temperature are set by the remote controllers 92 of ₂ and the operation start operation is performed.

In this case, if the required capacities of the indoor units B ₁ and B ₂ are different, the two-way valve 43 on the side with the larger required capacity, for example, the indoor unit B ₁ side is opened, and the side with the smaller required capacity, for example, the indoor unit B ₂ side. The two-way valve 53 is closed.

Then, the compressor 31 is started and the compressor 31
The refrigerant discharged from the four-way valve 3 as shown by the solid line arrow in FIG.
2, through the outdoor heat exchanger 33, the electronic expansion valves 41, 51, the indoor heat exchangers 42, 52, the flow rate adjusting valve 37, the two-way valve 43, the four-way valve 32, the check valve 35, the accumulator 36. The indoor units B ₁ and B ₂ start cooling parallel operation. During this cooling parallel operation, the capacity of the compressor 31 (= output frequency F of the inverter circuit 82) is set to the indoor units B ₁ , B.
Control according to the sum of the required capabilities of ₂ .

[0080] Further, the indoor unit B _1, B refrigerant evaporation temperature (= the temperature detected by the heat exchanger temperature sensor 45, 45) Tc _1, the absolute value ΔTc indoor unit of the difference between Tc ₂ B ₁ in _2, B ₂ To a predetermined value according to the ratio of required capacity of
The opening degree of the flow rate adjusting valve 37 is controlled.

By controlling the opening degree of the flow rate adjusting valve 37, the amount of the refrigerant flowing through the indoor unit B ₂ having the smaller required capacity is set to an appropriate state corresponding to the required capacity. Consequently, the amount of the refrigerant flowing to the indoor unit B ₁ is set to the proper state corresponding to the required capacity of the indoor unit B _1.

The degree of refrigerant superheat in the indoor heat exchangers 42 and 52 (= the difference between the temperature detected by the heat exchanger temperature sensors 45 and 55 and the temperature detected by the refrigerant temperature sensors 46 and 56) is detected,
The opening degrees of the electronic expansion valves 41 and 51 are controlled so that the detected refrigerant superheat degrees become constant values.

In this case, since a sufficient amount of the refrigerant is flowing in the indoor unit B ₁ on the side having a large required capacity,
The refrigerant superheat degree control by the electronic expansion valve 41 works effectively, and the refrigerant superheat degree in the indoor heat exchanger 42 can be always maintained constant.

Moreover, since an appropriate and sufficient amount of the refrigerant is flowing also to the indoor unit B ₂ on the side having a small required capacity, the refrigerant superheat degree control by the electronic expansion valve 51 works effectively, and the indoor heat exchanger 52 is operated. The degree of superheat of the refrigerant can be always maintained constant. Therefore, the refrigeration cycle becomes stable and an appropriate cooling capacity can be obtained. By the way, in this cooling parallel operation, the required capacities of the indoor units B ₁ and B ₂ may be almost the same.

[0085] In this case, (the temperature detected by the = heat exchanger temperature sensor 45, 55) refrigerant evaporation temperature in the indoor unit B _1, B ₂ monitors Tc _1, Tc _2, the larger side for example indoor unit among the two The two-way valve 43 on the B ₁ side is closed, and the two-way valve 53 on the smaller side, for example, the indoor unit B ₂ side is opened. The relationship of opening / closing of the two-way valves 43, 53 here is opposite to the case of different required capacities.

Further, the opening of the flow rate adjusting valve 37 is controlled so that the absolute value ΔTc of the difference between the refrigerant evaporation temperatures Tc ₁ and Tc ₂ becomes substantially zero. By controlling the opening of the flow rate adjusting valve 37, an appropriate amount of refrigerant is distributed to the indoor units B ₁ and B ₂ . Next, it is assumed that the heating operation mode and the desired indoor temperature are set by the remote controllers 92 of the indoor units B ₁ and B ₂ , respectively, and the operation start operation is performed.

In this case, if the required capacities of the indoor units B ₁ and B ₂ are different, the two-way valve 43 on the side with the larger required capacity, for example, the indoor unit B ₁ side is opened, and the side with the smaller required capacity, such as the indoor unit B ₂ side The two-way valve 53 is closed.

Then, the compressor 31 is started and the compressor 31
The refrigerant discharged from the four-way valve 3 as shown by the broken line arrow in FIG.
2, two-way valve 43, flow control valve 37, indoor heat exchanger 42,
52, the electronic expansion valves 41 and 51, the two-way valve 38, the refrigerant heater 60, and the accumulator 36, and the parallel heating operation of the indoor units B ₁ and B ₂ is started.

During this heating parallel operation, the capacity of the compressor 31 (= output frequency F of the inverter circuit 82) and the heating amount of the refrigerant heater 60 (= combustion amount of the gas burner 61) are required by the indoor units B ₁ and B ₂ . Control according to the total capacity.

Further, the absolute value ΔTg of the difference between the temperatures (= the temperatures detected by the refrigerant temperature sensors 46 and 56) Tg ₁ and Tg ₂ of the refrigerant flowing into the indoor heat exchangers 42 and 52 is equal to that of the indoor units B ₁ and B ₂ . In order to make it a predetermined value according to the ratio of required capacity,
The opening degree of the flow rate adjusting valve 37 is controlled.

By controlling the opening of the flow rate adjusting valve 37, the amount of the refrigerant flowing into the indoor unit B ₂ having the smaller required capacity is set to an appropriate state corresponding to the required capacity. Consequently, the amount of the refrigerant flowing to the indoor unit B ₁ is set to the proper state corresponding to the required capacity of the indoor unit B _1.

The degree of superheat of the refrigerant in the refrigerant heater 60 (=
The difference between the temperature detected by the refrigerant temperature sensor 71 and the temperature detected by the refrigerant temperature sensor 72 is detected, and the opening amounts of the electronic expansion valves 41 and 51 are simultaneously controlled by the same amount so that the detected refrigerant superheat degree becomes a constant value. To do.

As described above, since an appropriate amount of the refrigerant is always supplied to the indoor units B ₁ and B ₂ , it is possible to solve the problem that a large amount of the liquid refrigerant is accumulated in the indoor unit having the smaller required capacity. The refrigerant circulation amount does not become insufficient in the entire refrigeration cycle. Therefore, it is possible to prevent a decrease in the refrigerant temperature during the refrigeration cycle and obtain a sufficient heating capacity.

Moreover, since the circulating amount of the refrigerant is not insufficient, it is not necessary to increase the amount of the refrigerant enclosed in advance, and therefore, the large capacity liquid receiver (liquid tank) is not required. This prevents an increase in the size of the entire device and an increase in cost. Further, since the refrigerant circulation amount is not insufficient, it is not necessary to increase the rotation speed of the compressor motor 31M, and it is possible to prevent an increase in power consumption. By the way, in this heating parallel operation, the required capacities of the indoor units B ₁ and B ₂ may be almost the same.

In this case, the temperature of the refrigerant flowing into the indoor heat exchangers 42 and 52 (= the temperature detected by the refrigerant temperature sensors 46 and 56) Tg ₁ and Tg ₂ is monitored, and the larger one of them, for example, the indoor unit B. _{The one-} way two-way valve 43 is closed, and the smaller one, for example, the two-way valve 53 on the indoor unit B ₂ side is opened. The relationship of opening / closing of the two-way valves 43, 53 here is opposite to the case of different required capacities.

Further, the opening of the flow rate adjusting valve 37 is controlled so that the absolute value ΔTg of the difference between the refrigerant temperatures Tg ₁ and Tg ₂ becomes substantially zero. By controlling the opening of the flow rate adjusting valve 37,
An appropriate amount of refrigerant is distributed to each of the indoor units B ₁ and B ₂ . On the other hand, in the heating parallel operation, if any _one of the indoor units B ₁ and B ₂ is stopped,
The refrigerant recovery shown in is executed.

For example, when the indoor unit B ₁ is stopped, the two-way valve 43 is closed, the flow rate adjusting valve 37 and the expansion valve 4 are closed.
1 is maintained at the set opening degree. In this case, the refrigerant passing through the two-way valve 53 on the operating side flows into the indoor heat exchanger 42 through the flow rate adjusting valve 37, and the refrigerant accumulated in the indoor heat exchanger 42 blows to the low pressure side through the expansion valve 41. To be done.
The set openings of the flow rate adjusting valve 37 and the expansion valve 41 are
It is set to an optimum value so that no unpleasant refrigerant noise is generated when the refrigerant passes through.

At the time of this refrigerant recovery, the time count t is started and the operating frequency F of the compressor 31 is set to the set value F ₂
Set to. This operating frequency F ₂ is for ensuring a sufficient amount of refrigerant blow even when the temperature of the indoor heat exchanger 52 on the operating side is low. Then, the temperature Tc detected by the heat exchanger temperature sensor 55, that is, the temperature of the indoor unit B ₂ on the operating side is taken in, and the detected temperature Tc is compared with the set value T ₂ . If the detected temperature Tc is lower than the set value T ₂ (Tc ≦ T ₂ ), the refrigerant recovery at the operating frequency F ₂ is continued.

When the detected temperature Tc exceeds the set value T ₂ , (T
c> T ₂ ), the operating frequency F is reduced from F ₂ to F ₁ , and this time the detected temperature Tc and the set value T ₁ (<T ₂ )
Compare with.

If the detected temperature Tc is higher than the set value T ₁ (T ₁ ≤Tc ≤T ₂ ), the refrigerant recovery at the operating frequency F ₂ is continued. However, the detected temperature Tc is the set value T ₁
When it is less than (Tc <T ₁ ), the operating frequency F is increased from F ₁ to the original F ₂ .

If the stop of the indoor unit B ₁ is based on a different request, that is, the request of the cooling operation mode or the blowing operation mode, only the operation of the indoor fan 44 is turned on and the indoor unit B ₁ blows air.

If the stop of the indoor unit B ₁ is based on an air-conditioning load or a stop operation instead of an abnormal request, the indoor fan 4
Prohibit the operation of 4. This ban has a blast effect,
This is to deal with the problem that the refrigerant that has flowed into the indoor heat exchanger 42 for recovering the refrigerant is heat-exchanged and condensed, which makes it difficult to recover the refrigerant or promotes the shortage of the refrigerant. Is prevented in advance.

When the time count t reaches a certain time ts (t ≧ ts), the flow control valve 37 and the expansion valve 41 are fully closed based on the fact that the stopped indoor unit is B ₁ . That is, the refrigerant recovery is completed.

As described above, by performing the refrigerant recovery when the operation of the indoor unit is stopped, it is possible to eliminate the shortage of the circulation amount of the refrigerant together with the function of distributing the refrigerant by the flow rate adjusting valve 37, and it is always necessary and sufficient. The heating capacity can be secured.

In particular, when the temperature of the indoor unit on the operating side is high during the recovery of the refrigerant, the amount of refrigerant circulating in the entire refrigeration cycle becomes excessive, the pressure on the high-pressure side rises abnormally, and the operation stops due to the function of high-pressure protection. Although there is a concern, since the capacity of the compressor 31 is reduced under such conditions, a reliable refrigerant does not occur without causing an abnormal increase in the high-pressure side pressure, and thus without causing an unnecessary shutdown of the compressor 31. It can be recovered. Moreover, regarding the opening degree of the flow rate adjusting valve 37 and the opening degree of the expansion valve 41 (or 51) at the time of refrigerant recovery,

In the above embodiment, the operating frequency F of the compressor 31 is changed in accordance with the temperature of the indoor heat exchanger of the driver's indoor unit during the recovery of the refrigerant, but the indoor heat exchanger of the driver's indoor unit is changed. A configuration in which the temperature is changed according to the temperature of the refrigerant flowing out of the indoor heat exchangers B ₁ and B ₂ (the temperature detected by the temperature sensor 46 or 56) (the temperature detected by the temperature sensor 71). May be A third embodiment of the present invention will be described. This example
It corresponds to the air conditioner of claim 4. Here, not only when the operation of the indoor units is stopped, but also when the number of operating indoor units is increased, the refrigerant recovery is executed.

First, as shown by broken lines in FIG. 7, refrigerant temperature sensors 47 and 57 are attached to the liquid side pipes W ₁ and W ₂ between the indoor heat exchangers 42 and 52 and the expansion valves 41 and 51, respectively. The function of the outdoor control unit 80 is different as described below for (13) and (14) in the second embodiment.
It does not have the function of (15).

(13) During heating operation, indoor units B ₁ and B
₍₂₎ A means for carrying out the refrigerant recovery by continuing the flow of the refrigerant to the indoor unit whose operation is stopped or the indoor unit on the low capacity side for a predetermined time when the number of operating vehicles changes.

(14) The temperature of the indoor heat exchanger of the stopped indoor unit or the low capacity indoor unit (sensed temperature of the heat exchanger temperature sensor 45 or 55) and the refrigerant flowing out of the indoor heat exchanger during the above predetermined time Temperature (refrigerant temperature sensor 47
Or a detected temperature of 57). Other configurations are the same as those in the second embodiment. The operation will be described with reference to the flowchart of FIG.

During the heating operation, the indoor units B ₁ and B ₂ 2
When the unit operation is changed to the single unit operation, the refrigerant recovery is executed for the stopped indoor unit. In addition, when the indoor units B ₁ and B ₂ are changed from one unit operation to two units operation and the required capacity of the indoor unit for starting operation is larger than the required capacity of the already operated indoor unit, the low capacity side, that is, Refrigerant recovery is performed for indoor units that are already in operation.

For example, when the operation of the indoor unit B ₁ is stopped from the operation of the two indoor units B ₁ and B ₂ , the refrigerant recovery is executed for the indoor unit B ₁ . Further, when the indoor unit B ₂ is activated from the operation of one indoor unit B ₁ to become _{two and} the required capacity of the activated indoor unit B ₂ is larger than the required capacity of the indoor unit B ₁ , Refrigerant recovery is executed for the indoor unit B ₁ .

That is, in the refrigerant recovery for the indoor unit B ₁ , the two-way valve 43 is closed and the flow rate adjusting valve 37 and the expansion valve 41 are maintained at the set opening degrees. In this case, the refrigerant passing through the two-way valve 53 on the operating side flows into the indoor heat exchanger 42 through the flow rate adjusting valve 37, and the refrigerant accumulated in the indoor heat exchanger 42 blows to the low pressure side through the expansion valve 41. To be done.

At the time of this refrigerant recovery, the time count t ₁ is started and the temperature T detected by the heat exchanger temperature sensor 45 is detected.
difference between the temperature c and the temperature Tg detected by the refrigerant temperature sensor 46, ΔTcg
(= Tc-Tg) is calculated. Then, the temperature difference ΔTcg is compared with a set value (for example, 2 degrees C). If the temperature difference ΔTcg is equal to or greater than the set value (ΔTcg ≧ 2), it is judged that the refrigerant to be recovered still remains, and the refrigerant recovery is continued as it is.

When the temperature difference ΔTcg falls below the set value (ΔTcg
<2) Under the judgment that the amount of the refrigerant to be recovered has decreased, the refrigerant recovery is terminated after 10 seconds of the time count t ₂ has elapsed. Even if the temperature difference ΔTcg does not fall below the set value, the refrigerant recovery is ended there after 80 seconds based on the time count t ₁ .

As described above, by performing the refrigerant recovery when the operation of the indoor unit is stopped, the shortage of the refrigerant circulation amount can be eliminated together with the refrigerant distributing action of the flow rate adjusting valve 37, and it is always necessary and sufficient. The heating capacity can be secured.

In particular, since the execution time of the refrigerant recovery is changed according to the difference between the temperature of the heat exchanger and the temperature of the refrigerant flowing out of the heat exchanger, it is unnecessary even though the refrigerant recovery has already been completed. It is possible to solve the problem that the circulation of the refrigerant continues, and improve the operation efficiency.

In each of the above embodiments, the indoor unit B
_Although the distribution of the refrigerant to ₁ and B ₂ is covered by the change in the opening degree of the electronic flow rate adjusting valve 37, as shown in FIG. 13, instead of the electronic flow rate adjusting valve 37 and the two-way valves 43 and 53, a plurality of The electronic flow rate adjusting valves 101 and 102 may be adopted, and the refrigerant may be distributed to the indoor units B ₁ and B ₂ by changing the respective opening degrees of the electronic flow rate adjusting valves 101 and 102. Also in this case, similar refrigerant recovery can be performed.

[0118]

As described above, according to the present invention,

In the air conditioner of claim 1, during the heating operation,
Stopping the operation of the refrigerant heater while continuing the operation of the compressor, because it is configured to recover the refrigerant accumulated in the outdoor heat exchanger by the suction pressure of the compressor, without giving a cold air feeling in the room, Refrigerant can be recovered.

In the air conditioner of claim 2, during heating operation,
When the operation of at least one of the indoor units is stopped, the refrigerant is continuously circulated to the stopped indoor unit for a certain time to perform the refrigerant recovery, and at the time of the refrigerant recovery, the indoor heat exchanger of the operating indoor unit. The temperature of the compressor, the temperature of the refrigerant flowing out of the indoor heat exchanger, or the temperature of the refrigerant flowing out of the indoor heat exchanger and the temperature of the refrigerant merged, so that the capacity of the compressor is controlled. It is possible to reliably collect the refrigerant without causing an abnormal increase in pressure and, in turn, without causing an unnecessary operation stop of the compressor.

In the air conditioner of claim 3, during heating operation,
When the operation of at least one of the indoor units is stopped, the refrigerant is continuously distributed to the stopped indoor unit for a certain period of time to perform the refrigerant recovery, and at the time of the refrigerant recovery, the blowing of the stopped indoor unit is prohibited. Since the configuration is adopted, it is possible to surely collect the refrigerant without promoting the shortage of the refrigerant.

In the air conditioner of claim 4, during heating operation,
When the number of operating indoor units changes, the refrigerant is continuously flowed to the stopped indoor unit or the indoor unit on the low capacity side for a predetermined time to perform the refrigerant recovery, and the predetermined time for the refrigerant recovery is stopped. Since it is configured to vary according to the difference between the temperature of the indoor heat exchanger of the indoor unit or the low-capacity indoor unit and the temperature of the refrigerant flowing out of the indoor heat exchanger, the time for circulating the refrigerant is set to an appropriate state. It can be set and the operation efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a control circuit according to a first embodiment of the present invention.

FIG. 1 is a diagram showing a configuration of a refrigeration cycle according to a first embodiment.

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

FIG. 4 is a diagram showing a heating amount control condition of the first embodiment.

FIG. 5 is a diagram showing an example of changes in temperature difference ΔT in the first embodiment.

FIG. 6 is a flowchart for explaining refrigerant recovery control according to the first embodiment.

FIG. 7 is a diagram showing a configuration of a refrigeration cycle according to second and third embodiments of the present invention.

FIG. 8 is a block diagram showing a configuration of control circuits according to second and third embodiments.

FIG. 9 is a flowchart for explaining the overall operation of the second and third embodiments.

FIG. 10 is a flowchart for explaining the overall operation of the second and third embodiments.

FIG. 11 is a flowchart for explaining refrigerant recovery control according to the second embodiment.

FIG. 12 is a flowchart for explaining refrigerant recovery control according to the third embodiment.

FIG. 13 is a diagram showing a configuration of a main part of a modified example of the refrigeration cycle of the second and third embodiments.

[Explanation of symbols]

1 ... Variable capacity compressor, 2 ... Four-way valve, 3 ... Outdoor heat exchanger,
6 ... Indoor heat exchanger, 9 ... Refrigerant heater, A ... Outdoor unit, B ... Indoor unit, 20 ... Outdoor controller, 23 Indoor controller.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 25, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a control circuit according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a refrigeration cycle of the first embodiment.

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

FIG. 4 is a diagram showing a heating amount control condition of the first embodiment.

FIG. 5 is a diagram showing an example of changes in temperature difference ΔT in the first embodiment.

FIG. 6 is a flowchart for explaining refrigerant recovery control according to the first embodiment.

FIG. 7 is a diagram showing a configuration of a refrigeration cycle according to second and third embodiments of the present invention.

FIG. 8 is a block diagram showing a configuration of control circuits according to second and third embodiments.

FIG. 9 is a flowchart for explaining the overall operation of the second and third embodiments.

FIG. 10 is a flowchart for explaining the overall operation of the second and third embodiments.

FIG. 11 is a flowchart for explaining refrigerant recovery control according to the second embodiment.

FIG. 12 is a flowchart for explaining refrigerant recovery control according to the third embodiment.

FIG. 13 is a diagram showing a configuration of a main part of a modified example of the refrigeration cycle of the second and third embodiments.

[Explanation of Codes] 1 ... Variable capacity compressor, 2 ... Four-way valve, 3 ... Outdoor heat exchanger,
6 ... Indoor heat exchanger, 9 ... Refrigerant heater, A ... Outdoor unit, B ... Indoor unit, 20 ... Outdoor controller, 23 Indoor controller.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsumi Furui 336 Tatehara, Fuji City, Shizuoka Prefecture Toshiba Corporation Fuji Factory

Claims (4)

[Claims] 1. A heat pump type refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger are communicated with each other, and a compressor is provided from a communication portion of the outdoor heat exchanger and the decompressor. The refrigerant heater provided in communication with the suction port of the compressor and the refrigerant discharged from the compressor are caused to flow through the four-way valve, the indoor heat exchanger, the pressure reducer, and the refrigerant heater, and the refrigerant heater is turned on to perform the heating operation. And a means for recovering the refrigerant accumulated in the outdoor heat exchanger by suction pressure of the compressor during heating operation, stopping the operation of the refrigerant heater while continuing the operation of the compressor. An air conditioner characterized by being equipped. 2. An air conditioner, comprising an outdoor unit having a compressor and an outdoor heat exchanger, and a plurality of indoor units each having an indoor heat exchanger, and capable of cooling and heating operations, during heating operation. A means for carrying out the refrigerant recovery by continuing the circulation of the refrigerant to the stopped indoor unit for a certain time when the operation of at least one of the indoor units is stopped; A means for controlling the capacity of the compressor according to the temperature of the heat exchanger, the temperature of the refrigerant flowing out from the indoor heat exchanger, or the temperature of the refrigerant flowing out of the indoor heat exchangers and joined. An air conditioner characterized by being equipped. 3. An air conditioner comprising a compressor, an outdoor unit having an outdoor heat exchanger, and a plurality of indoor units each having an indoor heat exchanger, wherein each of the indoor units is capable of cooling and heating operations. When the required operation mode of the unit is different, the heating operation is preferentially executed and the indoor units requesting other than heating are stopped and only the air is blown. When at least one of the stopped indoor units is stopped, the means for continuing the circulation of the refrigerant to the stopped indoor unit for a fixed time to perform the refrigerant recovery, and the means for prohibiting the ventilation of the stopped indoor unit at the time of this refrigerant recovery are provided. An air conditioner characterized by that. 4. An air conditioner, comprising an outdoor unit having a compressor and an outdoor heat exchanger, and a plurality of indoor units each having an indoor heat exchanger, capable of cooling and heating operations, during heating operation. When the number of operating indoor units changes, a means for carrying out the refrigerant recovery by continuing the circulation of the refrigerant to the indoor unit whose operation is stopped or the indoor unit on the low capacity side for a predetermined time, and stopping the predetermined time An air conditioner comprising: means for varying the temperature of the indoor heat exchanger of the indoor unit or the low-capacity indoor unit and the temperature of the refrigerant flowing out from the indoor heat exchanger.