JP3424868B2 - Multi-system 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-system air conditioner comprising an outdoor unit having a plurality of compressors including a variable capacity compressor and a plurality of indoor units each having a refrigerant flow rate adjusting valve.

[0002]

2. Description of the Related Art In a multi-system air conditioner having the above structure, when an outdoor unit is in a heating operation and there is an indoor unit that is suspended because a detected room temperature approaches a set temperature, There is a phenomenon (also referred to as "liquid stagnation") that refrigerant accumulates in a heat exchanger of an indoor unit that has been stopped. Refrigerant stagnation in the heat exchanger of the indoor unit that is not operating is due to system operation.
In some cases, this causes a shortage of the refrigerant, resulting in a lack of capacity in the operating indoor unit, and in the worst case, the low pressure abnormality of the refrigerant causes the protection device to operate and stop the entire system. In order to avoid such an undesired situation, the refrigerant flow rate adjusting valve of the stopped indoor unit is opened and closed for a certain period of time for a certain period of time, so that the heat exchanger of the indoor unit in which the operation is stopped is stopped. A refrigerant recovery operation is performed to recover the refrigerant that has accumulated in the.

[0003]

In the case where the refrigerant stays in the indoor unit when the operation is stopped, that is, when the refrigerant recovery operation is performed to avoid liquid stagnation, the operation is stopped without increasing the rotation speed of the compressor. When the refrigerant recovery operation is performed by opening and closing the refrigerant adjustment valve of the indoor unit, it becomes difficult for the refrigerant to flow to the operating indoor unit. In particular, "heat exchanger capacity of stop unit" ≥ "heat exchange during operation" Capacity, "the capacity of the operating unit tends to decrease each time the refrigerant recovery operation is performed. Further, when the refrigerant flow rate control valve is not controlled by intermittent opening / closing control but only by controlling the operating time, the refrigerant may not be collected in time depending on the operating conditions, causing a situation of insufficient refrigerant, that is, insufficient capacity for the system, i.e., the operating unit. in the case of,
It has already been described that the protection device is activated and the system is stopped due to the decrease in the refrigerant pressure.

The present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide a multi-system air conditioner capable of efficiently recovering a refrigerant from a stopped unit without lowering the capacity of the operating unit. To aim.

[0005]

In order to achieve the above object, the invention of claim 1 includes: an outdoor unit having a plurality of compressors including a variable capacity compressor; and a plurality of units each having a refrigerant flow rate adjusting valve. Ri Do from the indoor unit, when it is paused by a portion of the indoor unit during operation in the heating operation mode is an operation stop or room thermostat-off, a first detecting means for detecting it, outdoor When the machine continues to perform the heating operation for the first set time, the second detecting means for detecting the heating operation and the first and second detecting means for collecting the refrigerant accumulated in the stopped indoor unit. together in response to the output detection signal to open the refrigerant flow control valve of the indoor unit stopped, increase the operating capacity of the variable capacity compressor for a preset capacity according to the number and capacity of the indoor unit stopped In a multi-system air conditioner and a control means for causing the tufts refrigerant recovery run, the compression
Discharge temperature sensor for detecting the discharge pipe temperature of the machine, and the discharge
If the temperature detected by the temperature sensor is above the first set temperature
Continued a second set time shorter than the first set time
And a third detection means for outputting a detection signal when
In response to the output detection signal of the third detecting means,
The control means performs the heating refrigerant recovery operation .

According to a second aspect of the present invention, in the multi-system air conditioner according to the first aspect, the compressor has a low capacity range.
During operation, the temperature value detected by the discharge temperature sensor is equal to the first temperature value.
The state of the second set temperature lower than the set temperature or more is the first
Detected when the fourth set time, which is shorter than the set time of, is continued
A fifth detecting means for outputting a signal is further provided, and the fifth detecting means is provided.
Of the control means in response to the output detection signal of the detection means of
The present invention is characterized by performing a bunch refrigerant recovery operation .

The invention of claim 3 relates to claim 1 and claim 1.
In the multi-system air conditioner according to 2 , the compressor
Suction pressure sensor that detects the suction side pressure of the
The suction temperature sensor that detects the temperature of the suction pipe and the suction pressure sensor
The pressure detected by the sensor is less than or equal to the first pressure setting value, and
Before the state of the detected temperature value is more than the set temperature of the suction temperature sensor
Note that the third set time, which is shorter than the first set time, has continued
A fourth detection means for outputting a detection signal,
The control is performed in response to the output detection signal of the fourth detection means.
The means performs a heating refrigerant recovery operation .

The invention of claim 4 is the invention of claims 1 to 3.
Defrosting completed in the multi-system air conditioner described in
Detects switching to heating operation afterwards and outputs detection signal
Further provided with a sixth detection means,
In response to the output detection signal, the control means causes the heating refrigerant recovery operation.
It is characterized by performing a roll .

The invention according to claim 5 is any one of claims 1 to 4.
In a multi-system air conditioner according to an indoor Sir
Outputs a detection signal by detecting the heating operation start by MOON
Further provided with a seventh detection means,
In response to the output detection signal, the control means causes the heating refrigerant recovery operation.
It is characterized by performing a roll .

[0010]

According to the invention of claim 1, the outdoor unit is operated for a predetermined time,
For example, when the heating operation is continuously performed for 60 minutes, it is estimated that the refrigerant has accumulated in the stopped indoor unit, the refrigerant flow rate adjusting valve of the indoor unit is opened, and the operation capacity of the variable capacity compressor is stopped in the stopped indoor unit. By increasing only the preset capacity according to the number and capacity of the units, it is possible to more rationally determine the capacity increase amount of the compressor and perform more efficient refrigerant recovery. Also, for each compressor
One of the discharge pipe temperatures is a predetermined value (for example, 120 ° C)
When the above state is continued for a predetermined time (for example, 5 minutes)
In addition, it is estimated that there is a possibility that refrigerant may accumulate,
Make a roll. By doing this, relatively simple detection means
It is possible to reliably estimate the situation in which the
A bunch refrigerant recovery operation can be performed.

According to the invention of claim 2, the compressor has a low capacity.
Operating in frequency, the discharge pipe temperature exceeds a predetermined value than the (e.g. 110
When the temperature is kept above ° C for a predetermined time (for example, 5 minutes)
Also, since it is estimated that there is a possibility of refrigerant retention,
More reliably than the invention of
It is possible to estimate and perform the heating refrigerant recovery operation.

According to the invention of claim 3, the suction side of the compressor
When the pressure is below the specified value and the suction pipe temperature is above the specified value
State for a predetermined time (for example, pressure 2 kg / cm2 or less, temperature
Degree 0 ° C or more, time 5 minutes, or pressure 3 kg / cm2 or less
When the temperature is lower than 15 ° C and the time is 5 minutes),
It is estimated that there is a possibility of refrigerant retention, and a heating refrigerant recovery operation is performed.
U This makes it possible to use a relatively simple detection means.
Claim 1 and Claim 2 in which a situation in which a refrigerant shortage is expected to occur
More reliable estimation than the invention of
It can be performed.

According to the fourth aspect of the present invention, the warm-up after defrosting is completed.
Estimated that there is a possibility that refrigerant will accumulate even when switching to cell operation.
Then, the heating refrigerant recovery operation is performed. By doing this, the ratio
A situation where a refrigerant shortage is expected by a relatively simple detection means
More reliably than the inventions of claims 1 to 3.
After that, the heating refrigerant recovery operation can be performed.

According to the invention of claim 5, the heating thermo-on
Even when the heating operation is started by, the heating refrigerant recovery operation is performed.
As a result, the refrigerant shortage and
The situation to be imagined is better than that of the inventions of claims 1 to 4.
It is possible to perform the heating refrigerant recovery operation by accurately estimating
It

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 shows an example of the configuration of a heat pump type refrigeration cycle to which the present invention is applied, and FIG. 3 is a block diagram showing the device configuration of a control system for an air conditioner according to the present invention.

As shown in FIG. 2, the outdoor unit SG is provided with two compressors 1A and 1B. One compressor 1A is operated at a constant speed by a commercial power source, and the other compressor 1B is shown. Variable speed operation with no inverter. Both compressors 1A and 1B constitute a variable capacity compressor capable of continuously adjusting the compression function force from zero output to an output corresponding to the sum of the individual outputs. What is necessary is that it can be configured as a variable capacity type as a whole. For example, two or more constant speed compressors are provided, or two or more variable speed compressors are provided. A variable compression device can be constructed. The discharge side of the constant speed compressor 1A is connected via a check valve 2 to the variable speed compressor 1A.
It is connected to the discharge side of B and is connected to the first input end of the four-way valve 3. Both compressors 1 are connected to the second input end of the four-way valve 3.
The suction sides of A and 1B are connected via an accumulator 4. A start compensation valve 5A is connected to the compressor 1A so that it can be bypassed via the accumulator 4, and both compressors 1A and 1B are high pressure so that they can be bypassed at the output side of the check valve 2 via the accumulator 4. Release valve 5B
Are connected. The four-way valve 3 switches the refrigerant circulation direction of the indoor heat exchanger and the outdoor heat exchanger by deactivating or energizing the operation solenoid according to the cooling operation or the heating operation.

The first output end of the four-way valve 3 has two sets of outdoor heat exchangers 6A and 6B connected in parallel, a heating operation expansion valve 7, a check valve 8 for bypassing the heating operation expansion valve 7, and a liquid tank. 9 to the indoor unit group.
Here, the number of outdoor heat exchangers being two is just an example, and other numbers may be used. In this embodiment, the indoor unit group is composed of three indoor units U1, U2,
It consists of U3. The first indoor unit U1 includes a refrigerant flow rate adjusting valve 10A and a capillary 21 which are connected in series with each other.
A and an indoor heat exchanger 11A. Similarly, the second and third indoor units U2 and U3 are connected to each other in series, and the refrigerant flow rate adjusting valves 10B and 10C and the capillary 21 are connected.
B and 21C and indoor heat exchangers 11B and 11C. The other end of the indoor heat exchangers 11A to 11C has a four-way valve 3
Are commonly connected to the second output terminals of the. The connection state shown corresponds to the cooling operation mode, and when the heating operation mode is switched by exciting the solenoid (not shown) of the four-way valve 3, the refrigerant from the compressors 1A and 1B first heats the indoor heat. Expansion valve 7 after passing through the vessels 11A to 11C
And circulates in the direction to reach the outdoor heat exchangers 6A and 6B.

The outdoor heat exchangers 6A and 6B have outdoor blowers 12A and 1A, respectively, in order to promote heat exchange with the atmosphere.
2B are provided, and indoor heat exchangers 11A to 11 are similarly provided.
Indoor blowers 13A, 13B, and 13C are provided in 1C to blow the cooling air or the heating air toward the room. Each indoor blower is included in the indoor unit of the corresponding indoor heat exchanger.

In the system of FIG. 2, the indoor unit U
Equipment other than 1 to U3, that is, both compressors 1A, 1B, check valve 2, four-way valve 3, accumulator 4, valves 5A, 5B,
The outdoor heat exchangers 6A and 6B, the expansion valve 7, the check valve 8, the liquid tank 9, and the outdoor blowers 12A and 12B constitute an outdoor unit SG. The outdoor unit SG is installed outdoors.

Common suction side pressure PS of the compressors 1A, 1B
Is measured by the pressure sensor 14, and the suction pipe temperature TS is measured by the temperature sensor 15. The discharge side pressure PD of both compressors is measured by the pressure sensor 16 at the outlet side of the check valve 2, and the discharge pipe temperatures TD1 and TD2 of the compressors 1A and 1B are measured by the temperature sensors 17A and 17B, respectively. Further indoor heat exchangers 11A to 11C
Liquid side temperature (expansion valve 7 side temperature) TE1A, TE1B, T
E1C is measured by the temperature sensors 20A, 20B, 20C, respectively, and the gas side temperature (four-way valve 3 side temperature) TE2 is measured.
A, TE2B and TE2C are temperature sensors 18A and 18A, respectively.
18B, 18C. Further, the room temperature TA1, TA2, TA3 of the room in which the indoor unit is installed is the temperature sensor 19A near the air inlet of each indoor unit,
19B, 19C. Each of these measurement signals is sent to each controller described later.

FIG. 3 shows an example of the configuration of a control system for controlling the refrigeration cycle shown in FIG.

Indoor controllers 30A, 30 including a microprocessor for each indoor unit U1, U2, U3
It is equipped with B and 30C. Indoor controllers 30A-3
A remote controller (hereinafter, referred to as “remote control”) 31A, 31B, 31C for giving an ON / OFF command for unit operation to 0C and setting a set temperature
Is included. These indoor controllers 30A-3
0C corresponds to the room temperature T from the temperature sensors 19A to 19C.
Signals representing A1 to TA3 are input, and signals representing the temperatures TE1A to TE1C and TE2A to TE2C of the corresponding indoor heat exchangers 11A to 11C are also input from the temperature sensors 20A to 20C and 18A to 18C, which will be described later. In accordance with the above, the indoor air blowers 13A to 13C in the unit are controlled and the openings of the refrigerant flow rate adjusting valves 10A to 10C are controlled after performing necessary arithmetic processing.

The outdoor unit SG is provided with an outdoor controller 32 including a microprocessor. The outdoor controller 32 includes the indoor controllers 30A, 30B, 30.
Along with the command signal from C, the suction side pressure PS and the discharge side pressure PD of the compressors 1A and 1B from the pressure sensors 14 and 16 and the suction pipe temperature T from the temperature sensors 15, 17A and 17B.
Signals indicating S and the discharge pipe temperatures TD1 and TD2 are input. On the other hand, the outdoor controller 32 is connected to each indoor controller 30A, 30B, 30C,
After performing necessary arithmetic processing in accordance with commands from each indoor controller and each measurement signal, the compressor 1A is controlled to be turned on and off, its speed is adjusted to adjust the capacity of the compressor 1B, and an outdoor blower is used. 12A, 12B (generally referred to as outdoor blower 12), four-way valve 3, compressor start compensation valve 5A,
The high pressure release valve 5B is controlled to be turned on and off, and the four-way valve 3 is turned on and off (to switch between cooling operation and heating operation).

Before entering the description of the refrigerant recovery control of the present invention,
The basic operation of the apparatus shown in FIGS. 2 and 3 will be described.

In the apparatus of FIG. 2, on / off commands for operating the indoor unit and the outdoor unit are issued through remote controls 31A to 31C attached to each indoor unit. When the operation command is issued from the remote controller, the room temperatures TA1 to TA3 and the set room temperatures TB1 to TB3 are set in the indoor controllers 30A, 30B, and 30C for each indoor unit.
(A standard value preset inside or a value corrected by a remote controller) is compared, and the step signal F (X) selected corresponding to the deviation, that is, the temperature deviation ΔT (= room temperature TA−set room temperature TB). Is transmitted to the outdoor controller 32, the opening degree of the refrigerant flow rate adjusting valves 10A to 10C is adjusted, and the indoor blowers 13A to 13C of the indoor unit whose operation is turned on are drive-controlled.

The step signal F (X) is preset corresponding to the temperature deviation ΔT during the cooling operation and the heating operation, and is set to 1 according to the sign and absolute value of the temperature deviation ΔT.
It is classified and associated with step signals S0 to SF (the second code in the two characters is the hexadecimal representation of 0 to F) consisting of 6 steps, and the temperature deviation ΔT is less than or equal to a predetermined value during cooling operation or predetermined during heating operation. When the value is equal to or more than the value, S0 is set, so-called "thermo off" occurs, and operation is stopped. When the temperature deviation ΔT is equal to or higher than a predetermined value during the cooling operation or equal to or lower than the predetermined value during the heating operation, the so-called “thermo on” is performed, and the cooling operation or the heating operation is performed, and the step signal F (X ) (Signals S1 to SF
Are sent to the outdoor controller 32 from the indoor controllers 30A to 30C. X in the step signal F (X) is a variable for specifying the indoor unit, and X = 1 in the controller 30A, X = 2 in the controller 30B, and X in the controller 30C.
= 3. The outdoor controller 32 uses the step signal F transmitted from the indoor controllers 30A to 30C.
(X) is referred to and converted into a required frequency basic value G (X) corresponding to the rotation speed corresponding to the capacity of the compressor. FIG. 4 shows an example of a comparison table showing the relationship between the step signal F (X) and the required frequency basic value G (X). In the example of FIG. 4, the required frequency basic value G (X) in the step signal F (X) = S0 to S2 is zero (= 0.0). The outdoor controller 32 refers to this comparison table to determine the step signal F (X).
To a required frequency basic value G (X), and further multiplied by a weight H (X) according to the capacities of the indoor units U1, U2, U3 of the transmission source, and the sum Σ {G (X) · H (X )} And use it as the required compression function. In this embodiment, since it is premised that three indoor units are provided, the sum of the three values will be obtained. When the indoor units have the same capacity, the weights H (X) have the same value, and with respect to the indoor units that are not operating, F (X) = S0 is unconditionally set, and thus G (X) = 0.
And The outdoor controller 32 operates only the compressor 1B or both of the compressors 1A and 1B according to the required compression function force thus obtained. In that case, of the required compression functional force, the compressor 1A bears the fixed capacity portion corresponding to the constant speed rotation, and the variable speed drive compressor 1B bears the lacking portion (variable capacity portion).

An object of the present invention is to solve the refrigerant retention problem during heating operation. In order to solve this problem, the refrigerant recovery operation is performed according to the present invention. Hereinafter, a series of flows will be described with reference to the flowcharts of FIG. 1 and FIG.

In FIG. 1, first, it is checked whether or not the heating operation is being performed (step 101), whether or not the defrosting operation is being performed (step 102), and whether or not all indoor units are in the heating thermo-on state (step 103). As a result of these checks, it is checked whether or not the refrigerant recovery control condition is satisfied under the condition that the heating operation is performed, the defrosting operation is not performed, and all indoor units are not in the heating thermo-on (step 104). Details of the refrigerant recovery control conditions in this step will be described later with reference to FIGS.

As for the check in step 102, if frost adheres to the outdoor heat exchanger during the heating operation, the efficiency will decrease. Therefore, when viewed from the indoor side, the defrosting operation corresponding to the cooling operation is temporarily performed. This operation mode corresponds to the cooling operation when viewed from the indoor side, and when the heating operation is performed immediately after the end, it cannot be handled in the same manner as when it is not. Therefore, it is checked whether or not the heating operation is performed immediately after the defrosting operation is completed. In the case of the heating operation after the defrosting operation is completed, the refrigerant recovery operation is performed because it is highly likely that the refrigerant remains. Also, regarding the check in step 103,
If all are thermo-on, the problem of refrigerant recovery operation does not occur.

First, the operating time T1 of the outdoor unit, which is common to all indoor units, is checked (step 10).
4 ). When the time T1 exceeds 60 minutes, the refrigerant recovery operation (step 105 to step 107 ) is performed.

When the refrigerant recovery control conditions are satisfied in step 104, the adjustment valve 10 (general term for the adjustment valves 10A to 10C) of the stopped indoor unit is set to the indoor controller 30.
It is opened through (inclusive of the indoor controllers 30A to 30C) (step 105), and the required frequency basic value G (X) for the compressor 1B is set to the G (X) value corresponding to the correction 1 in the following Table 1. Command the corresponding G (X) = 17. Table 1 Correction 1 = + 17, Correction 2 = + 9, Correction 3 = + 0

Thereafter, the refrigerant recovery control according to the present invention is started (step 107).

5 to 8 show a flow of judging the refrigerant recovery control condition. The first refrigerant recovery control condition is shown in FIG.
, The discharge pipe temperature TD1 or TD2 is 120
The state in which the temperature is higher than ° C has continued for T 2 = 5 minutes (steps 111 and 112 and steps 113 and 1).
14). As shown in FIG. 6, the second refrigerant recovery control condition is commanded to the compressor 1B with a low step signal F (X) = S3 or S4, and the discharge pipe temperature T
The condition that D2 is 110 ° C. or higher has continued for T 4 = 5 minutes (steps 115, 116 and 1).
17). As shown in FIG. 7, the third refrigerant recovery control condition is that the suction side pressure PS is 2 (kg / cm 2) or less,
Moreover, the state in which the suction pipe temperature TS exceeds 0 ° C continues for T3 = 5 minutes (steps 118 to 120), or the suction side pressure PS is 3 (kg / cm2) or less, and the suction pipe temperature TS is 15 This means that the state of exceeding ° C continues for 5 minutes (steps 121 to 123). As shown in FIG. 8, the fourth refrigerant recovery control condition checks whether the heating thermostat is switched from the heating thermostat to the heating thermostat (step 124) or the heating operation immediately after the defrosting operation is completed (step 12).
5). This check causes a decrease in efficiency if frost adheres to the outdoor heat exchanger during heating operation, so when viewed from the indoor side, defrosting operation equivalent to cooling operation is temporarily performed, but this operation mode is from the indoor side. Looking at it, it corresponds to the cooling operation, and if the heating operation is performed immediately after the end, the same handling cannot be performed unless it is done. Therefore, it is necessary to check whether or not it is the heating operation after the defrosting operation is completed. In the case of the heating operation after the defrosting operation is completed, the refrigerant recovery operation is performed because it is highly likely that the refrigerant remains. This is when the heating thermo-on is continued for 60 minutes as the refrigerant recovery control condition (step 127).

The control contents when the refrigerant recovery control (step 107) is performed by the above flow will be described below.

Refrigerant recovery control is performed by slightly increasing the rotation speed of the compressor in order to shorten the time required to start blowing hot air indoors. Then, this control is performed by distinguishing between three patterns of "heating activation pattern" control, "during heating operation" control, and "at the time of defrosting end" control.

First, the "heating activation pattern control" will be described. For the system operation at the time of starting the heating operation, the mode is divided according to the operation of the two compressors 1A and 1B, and the control is performed accordingly. α mode: operating both compressors 1A, 1B β mode: operating only variable speed compressor 1B

The first control mode is applied to both α and β modes. When the heating start command is issued, the variable N for checking the number of times the thermostat is turned on / off is first cleared (N = 0) according to FIG. 9 (step 201), and it is checked whether or not the heating thermostat is turned on (step 202). ). If the thermostat is off, it will be in a standby state. When the thermostat is turned on, N is incremented (N = N + 1) (step 203),
At this stage, N = 1. In addition, the value of N is + every time "thermo off" → "thermo on" is repeated as described later.
1 is incremented. Therefore, the number N of times of thermo-on is checked here (step 204), and N =
If 1, then it is checked whether the required frequency basic value G (X) in the chart of FIG. 4 has become 0.1 or more (step 2).
05). Here, G (X) does not become 0.1 or more, that is, G (X) = 0 remains, and the compressor is not operated, and the heating start operation is stopped. , Return to step 201 and wait for the thermoon again. When it is determined that the G (X) value has increased from 0 to 0.1 or more, a correction 1 (= + 17) is added to the required frequency basic value G (X) according to Table 1 for refrigerant recovery according to the present invention. . That is, the calculation process of G (X) = G (X) +17 is performed (step 206).

If N = 2 in step 204, correction 2 (= + 9) is added. That is, G (X) =
G (X) +9 is calculated (step 207). Similarly, when N = 3, correction 3 (= + 0) is added.
That is, G (X) = G (X) +0 is calculated (step 208). When N ≧ 4, the normal control corresponding to the above-mentioned basic control based on the temperature deviation ΔT (= TA-TB) is performed under the condition of the normal operation, that is, the heating thermo-ON without performing any further correction ( Step 21
4).

In steps 206 to 208, G (X)
After the value is corrected, the maximum value of this G (X) value (corresponding to the maximum speed of the compressor) is set to 29.0, and G after each correction is set.
G (X) ≦ 29.0 so that the (X) value does not exceed it
Check whether or not (step 209), and if G
If (X)> 29.0, G (X) = 29.0 is corrected (step 210). The heating start-up operation is performed under the above conditions (step 211). When this start-up operation is started, the operation time is measured and it is checked whether 20 minutes have elapsed (step 212). If the thermostat is turned off within 20 minutes (step 213), the process returns to step 202 to wait for the next thermostat. When it turns on the thermo,
As described above, the increment process of N = N + 1 (step 203) is performed, and the G (X) value is corrected by adding the correction value one step higher (that is, a smaller G (X) value). When 20 minutes have elapsed in step 212, the process proceeds to step 206, and the correction of the correction 1 is made to the G (X) value, that is, G (X) = G, as in the case of the initial activation.
Perform (X) +17 processing. N in step 204
When ≧ 4, it is considered that the heating start operation and the refrigerant recovery operation have ended, and the heating normal operation according to the required frequency basic value G (X) determined based on the thermo-on / off and the temperature deviation ΔT is started (step 214).

After the heating is started in FIG. 10, after 20 minutes have passed with the same starting operation condition, the process returns to step 201 (step 212). If the thermostat is turned off within 20 minutes under the same start-up operating condition, step 20
Return to step 2 (step 213). When the thermostat is not turned off within 20 minutes, the pressure PS on the suction side of the compressor is monitored (step 221) and PS <0.3 (kg / cm2).
When the correction value of the G (X) value is the correction value 3, the process returns to step 211 (step 222), and during the thermo-ON of the correction value 3 for 20 minutes, it is not stopped even if PS <0.3. . In step 222, other than correction 3 (that is, when the heating start operation is not performed and the thermostat is not turned off within 20 minutes and the suction side pressure PS is less than 0.3, stop control is performed (step 223) to prevent restart. The timer is started (step 224), the correction is increased by one step (+ the numerical value is decreased) (step 225), and the process returns to step 201 (FIG. 9).

The second control mode is applied to the α mode and the β mode of the compressor 1A off condition.

In this case, as shown in FIG. 11, when the operation is started, the step signal command S5 in FIG. 4 is sent to the variable speed compressor 1B under the condition of thermo-on (step 231) (step 232). The time is counted from the transmission of this command (step 233), and after 2 minutes, the normal heating operation according to the required frequency basic value G (X) determined based on the temperature deviation ΔT is started (steps 233, 214).

The third control mode is the compressor 1
This is a heating start pattern under the A-on condition, and only the β mode is applied.

As shown in FIG. 12, when the operation is started, the step signal S5 command in FIG. 4 is sent to the compressor 1B under the condition of thermo-on (step 241), and the compressor start compensation valve 5A is issued an on (open) command. (Step 2
42). The time is counted from this command transmission, and after 1 minute has passed (step 243), the compressor 1A is turned on and the high pressure release valve 5B is turned on (open) (step 244). When 5 seconds have passed after this ON command (step 245), the start compensation valve 5A is turned off (closed) (step 246). Further, after 2 minutes have passed after the ON command to the compressor 1A (step 247), the high pressure release valve 5B is turned off (closed) (step 248). After this, the required frequency basic value G (X) determined based on the temperature deviation ΔT.
Then, the normal operation is performed according to (step 214).

The three modes have been described above. Next, the heating activation pattern cancellation control will be described with reference to FIG. The first release condition is that the discharge side pressure PD of the compressor has become 20 (kg / cm2) or more (step 261). The second release condition is that at least one of the discharge pipe temperatures TD1 and TD2 of the compressors 1A and 1B exceeds 115 ° C (step 262). The third cancellation condition is that there is no heating operation command from the indoor side (step 263). The fourth cancellation condition is that the cooling operation mode is selected on the indoor side (step 264).
Finally, for the fifth release condition, the correction value 3 is selected in Table 1,
In addition, the room temperature TA has reached the set value TB and the heating thermostat is off (step 265). 6 mentioned above
When any one of the two conditions is satisfied, the heating activation pattern control is released (step 266).

Next, the refrigerant recovery control during the "heating operation" will be described. In this case, as shown in FIG. 14, the constant speed compressor 1A is turned off, and the variable speed compressor 1B is independently operated by the S3 command (minimum rotation speed command) in FIG. 4 (step 301). After doing that for 2 minutes (step 3
02), the start compensation valve 5A is turned on (opened) (step 303). When this state is continued for 30 seconds (step 304), an ON command is issued to the compressor 1A and the high pressure release valve 5B (step 305), and the ON command
After 5 seconds, the start compensation valve 5A is turned off (steps 306 and 30).
7), and 2 minutes after the compressor 1A is turned on in step 305, the high pressure release valve 5B is turned off (step 30).
8, 309). During this period, the S3 command issued in step 301 continues. After the valve 5B is turned off, the normal operation is started (step 214).

Next, the refrigerant recovery control at the "end of defrosting" will be described. In this case, as shown in FIG. 15, instead of immediately shifting to the normal heating operation after defrosting is completed (the four-way valve 3 is switched from OFF to ON), the compressor 1A is turned on and the S3 command to the compressor 1B is issued. (FIG. 4) is continued for 2 minutes (steps 311 and 312), the refrigerant recovery control is performed, and then the normal operation (step 214) is performed. The refrigerant recovery control is also related to the control of the indoor unit, and when the refrigerant recovery control is started due to the completion of defrosting, the refrigerant recovery command is issued to the outdoor controller 3.
The controller 30 of the indoor unit whose operation is stopped from 2
It is transmitted to (the generic name of the controllers 30A to 30C) (step 315). This command continues for at least 5 minutes (step 316). After that, when the heating refrigerant recovery control ending condition described later is satisfied, the transmission of the refrigerant recovery control command is stopped at that time (steps 317 and 318).
Even when the heating refrigerant recovery control termination condition is not satisfied in step 317, the transmission of the refrigerant recovery control command is stopped after a further 5 minutes (10 minutes have elapsed) from the time point of 5 minutes in step 316 (step 3).
18, 319).

Next, the conditions for ending the heating refrigerant recovery control will be described. As shown in FIG. 16, the heating refrigerant recovery control ends when one of the following conditions is satisfied. The first case is when the heating activation pattern control release condition described with reference to FIG. 13 is satisfied (step 321). Second
In this case, 10 minutes have passed since the heating refrigerant recovery control was started (step 322). The third case is when the system is stopped, the thermostat is turned off, or the cooling operation is performed (step 323). When either of these conditions is satisfied, the heating refrigerant recovery control is ended (step 324).
15 minutes after the end of this refrigerant recovery control (even if the system is stopped or the thermostat is off or the cooling operation is continued)
Prohibits the refrigerant recovery control so that the next refrigerant recovery control is not performed even if the refrigerant recovery control condition is satisfied (steps 325 and 326). When 15 minutes have passed after the end of the refrigerant recovery control, the compression function force correction value is cleared (step 3
27) When the prohibition of the refrigerant recovery control is released and the control start condition is satisfied, the refrigerant recovery control can be restarted (step 328).

According to the above-mentioned embodiment, the state in which the outdoor unit SG is estimated to be insufficient refrigerant is detected from the information from each sensor, and the operating rotational speed of the compressor during the recovery control is determined according to the conditions. By changing the amount, it is possible to improve the refrigerant recovery capability from the indoor unit that is not operating and to perform efficient refrigerant recovery.

[0051]

According to the invention of claim 1, the outdoor unit has a predetermined size.
If the heating operation is continued for 60 minutes, for example,
It is estimated that the refrigerant stayed in the indoor unit when it was stopped, and
Capacity of opening the refrigerant flow control valve of the indoor unit of
The number of indoor units whose operating capacity of the variable compressor is stopped
And increase only the preset ability according to the capacity.
With, the ratio of compressor capacity increase can be determined more rationally,
More efficient refrigerant recovery can be performed. Also, each pressure
One of the discharge pipe temperatures of the compressor is a predetermined value (for example, 120
(° C) or higher for a predetermined time (for example, 5 minutes)
It is estimated that there is a possibility of refrigerant retention even when
Since recovery operation is performed, relatively simple detection means
More reliable estimation of the situation in which a refrigerant shortage is expected due to
Then, the heating refrigerant recovery operation can be performed.

According to the invention of claim 2, the compressor has a low capacity.
During operation in the range, the discharge pipe temperature is higher than a predetermined value (for example, 110
When the temperature is kept above ° C for a predetermined time (for example, 5 minutes)
Even so, I decided to assume that there is a possibility that refrigerant may accumulate.
Therefore, more reliably than the invention of claim 1
It is possible to perform the heating refrigerant recovery operation by estimating the conceivable situation.
Wear.

According to the invention of claim 3, the suction side of the compressor
When the pressure is below the specified value and the suction pipe temperature is above the specified value
State for a predetermined time (for example, pressure 2 kg / cm2 or less, temperature
Degree 0 ° C or more, time 5 minutes, or pressure 3 kg / cm2 or less
When the temperature is lower than 15 ° C and the time is 5 minutes),
It is estimated that there is a possibility of refrigerant retention, and a heating refrigerant recovery operation is performed.
As a result, the refrigerant can be detected by a relatively simple detection means.
The situation that is expected to be insufficient will be generated by claim 1 and claim 2.
More reliable estimation than heating
I can.

According to the invention of claim 4, the warming after the completion of defrosting
Estimated that there is a possibility that refrigerant will accumulate even when switching to cell operation.
However, since the heating refrigerant recovery operation is performed, it is relatively easy.
If there is a shortage of refrigerant due to a single detection method,
More reliable estimation than the inventions of claim 1 to claim 3
The heating refrigerant recovery operation can be performed.

According to the invention of claim 5, the heating thermo-on
The heating refrigerant recovery operation is performed even when the heating operation is started by
As a result, there is insufficient refrigerant due to the relatively simple detection means.
According to the inventions of claims 1 to 4,
Even more accurately, estimate the heating refrigerant recovery operation.
You can

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of a control flow of an air conditioner according to the present invention.

FIG. 2 is a system configuration diagram showing a refrigeration cycle to which the present invention is applied together with various sensors.

FIG. 3 is a block diagram of a control device for an air conditioner according to the present invention.

FIG. 4 is a chart showing a relationship between a step signal transmitted from an indoor unit and a required frequency basic value.

5 is a flowchart showing details of part of step 104 in FIG.

FIG. 6 is a flowchart showing details of part of step 104 in FIG.

FIG. 7 is a flowchart showing details of part of step 104 in FIG.

FIG. 8 is a flowchart showing details of part of step 104 in FIG.

FIG. 9 is a flowchart showing a part of a control flow applied to the first operation mode during heating start-up operation.

FIG. 10 is a flowchart showing another part of the control flow applied to the first operation mode during the heating start-up operation.

FIG. 11 is a flowchart showing a control flow applied to a second operation mode during heating startup operation.

FIG. 12 is a flowchart showing a control flow applied to a third operation mode during heating start-up operation.

FIG. 13 is a flowchart showing a heating start pattern release control flow.

FIG. 14 is a flowchart showing a flow of refrigerant recovery control during heating operation.

FIG. 15 is a flowchart showing a flow of refrigerant recovery control at the end of defrosting.

FIG. 16 is a flowchart showing the control content of refrigerant recovery control.

[Explanation of symbols] SG outdoor unit 1A constant speed compressor 1B variable speed compressor 3 four-way valve 6A, 6B outdoor heat exchanger 7 expansion valve 8 check valves 10A, 10B, 10C refrigerant flow rate control valve 11A, 11B, 11C indoor Heat exchanger 12A, 12B Outdoor blower 13A, 13B, 13C Indoor blower U1, U2, U3 Indoor unit 14 Suction pressure sensor 15 Suction temperature sensor 16 Discharge pressure sensor 17A, 17B Discharge temperature sensor 18A, 18B, 18C Indoor heat exchange gas side temperature sensors 19A, 19B, 19C room temperature sensor 20A, 20B, 20C indoor heat exchange liquid-side temperature sensor

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F25B 13/00 F24F 11/02

Claims (5)

(57) [Claims] An outdoor unit having a plurality of compressors including 1. A variable capacity compressor, Ri Do and a plurality of indoor units having a refrigerant flow control valve respectively, a portion during operation in the heating operation mode When the indoor unit is stopped or temporarily stopped by the indoor thermostat, it detects the first detecting means, and when the outdoor unit continues the heating operation for the first set time, detects it. Second detection means for recovering the refrigerant accumulated in the stopped indoor unit, and in response to the output detection signals of the first and second detection means, the refrigerant flow rate adjusting valve for the stopped indoor unit. And a control means for performing a heating refrigerant recovery operation that increases the operating capacity of the variable capacity compressor by a preset capacity according to the number and capacity of the indoor units that are stopped .
In a multi-system air conditioner, a discharge temperature sensor that detects a discharge pipe temperature of each compressor , and a temperature value detected by the discharge temperature sensor is equal to or higher than a first set temperature.
State of the second set time shorter than the first set time
And a third detection means that outputs a detection signal when continued.
In preparation for the above, in response to the output detection signal of the third detection means, the control
A multi-system air conditioner, wherein means performs the heating refrigerant recovery operation . 2. The multi-system air conditioner according to claim 1 , wherein the discharge temperature sensor is detected while the compressor is operating in a low capacity region.
Second set temperature whose output temperature value is lower than the first set temperature
The above state is set to the fourth setting which is shorter than the first setting time.
A fifth detection means for outputting a detection signal when the time continues
Further, the control is provided in response to the output detection signal of the fifth detection means.
It means a multi-system air conditioner, wherein a perform heating refrigerant recovery operation. 3. The multi-system air conditioner according to claim 1 , wherein a suction pressure sensor for detecting a suction side pressure of the compressor, and a suction temperature sensor for detecting a suction pipe temperature of the compressor. The pressure value detected by the suction pressure sensor is less than or equal to the first pressure setting value.
Below, and the detected temperature value of the suction temperature sensor is the set temperature.
The above state is set to the third setting shorter than the first setting time.
A fourth detection means for outputting a detection signal when the time continues
Further comprising: responsive to the output detection signal of the fourth detection means, the control
A multi-system air conditioner characterized in that the means performs heating refrigerant recovery operation . 4. The multi-system air conditioner according to claim 1 , wherein a switching to heating operation after defrosting is detected and a detection signal is detected.
Is further provided, and the control is performed in response to an output detection signal of the sixth detection means.
A multi-system air conditioner characterized in that the means performs heating refrigerant recovery operation . 5. The multi-system air conditioner according to any one of claims 1 to 4 , wherein a heating operation start by indoor thermo-on is detected and a detection signal is detected.
Is further provided, and the control is performed in response to an output detection signal of the seventh detection means.
A multi-system air conditioner characterized in that the means performs heating refrigerant recovery operation .