JPH0694956B2 - Multi-room air conditioner - Google Patents

Description

TECHNICAL FIELD The present invention relates to a multi-room air conditioner that optimally controls the refrigerant flow rate for each of a plurality of indoor heat exchangers.

[Conventional technology]

FIG. 3 is a refrigerant system diagram of a conventional multi-chamber air conditioner disclosed in, for example, Japanese Patent Laid-Open No. 62-87767, in which 1 is a refrigerant compressor, 2 is an outdoor heat exchanger, and 3 is an outdoor heat exchanger. Four-way valve,
4 is an accumulator, 5a and 5b are temperature type expansion valves provided for each indoor unit, 6a and 6b are indoor heat exchangers also provided for each indoor unit, and 7a and 7b are temperature type expansion valves, respectively. Temperature sensitive tubes 5a and 5b, and pressure equalizing tubes 8a and 8b of expansion valves 5a and 5b, respectively.

Next, the operation will be described.

During the cooling operation, the high-temperature and high-pressure refrigerant gas discharged from the refrigerant compressor 1 is condensed in the outdoor heat exchanger 2 to become the high-temperature and high-pressure refrigerant liquid, which is supercooled through the accumulator 4 and is then supplied to each indoor unit. Distributed and supplied. The refrigerant liquid supplied to each room is expanded by the expansion valves 5a and 5b to become a low-pressure liquid refrigerant, further evaporated in the indoor heat exchangers 6a and 6b, and then becomes superheated gas via the accumulator 4. The cycle of being sucked into the refrigerant compressor 1 is repeated.

The expansion valves 5a and 5b of the indoor unit are indoor heat exchangers 6a obtained from respective temperature sensitive tubes 7a and 7b and pressure equalizing tubes 8a and 8b.
According to the superheat signals at the outlets of 6 and 6b, the flow rates of the refrigerant supplied to the indoor heat exchangers 6a and 6b are individually adjusted. That is, if the superheat signal is larger than a set value, the supply refrigerant amount is increased, and if the superheat signal is lower than the set value, the opening amounts of the expansion valves 5a and 5b are individually adjusted so as to reduce the supply refrigerant amount. It

[Problems to be solved by the invention]

Since the conventional multi-room air conditioner is configured as described above, when the refrigerant flow rate on one indoor unit side is changed, the overall refrigerant flow rate also changes, so the refrigerant on the other indoor unit side The flow rate will also be greatly affected by this.Therefore, if the refrigerant flow rate of one indoor unit is adjusted to the target, the refrigerant flow rate of the other indoor unit will deviate from the target, and if this is readjusted, the above one will There was a problem that a hunting phenomenon of being out of the target occurred and a stable cycle operation of the refrigerant flow rate was not possible.

The present invention has been made to solve the above problems, and it is possible to prevent changes in the refrigerant flow rate of each indoor unit from affecting each other, and to perform stable cycle operation. The object is to obtain a multi-room air conditioner that can be used.

[Means for solving problems]

The multi-room air conditioner according to the present invention is provided with a controller for driving the expansion valve, and during the cooling operation, the opening direction control of the expansion valve of each indoor unit is performed based on the superheat on the indoor heat exchanger side, and then closed. The direction control is performed based on the intake gas superheat of the refrigerant compressor.

[Action]

The drive controller in the present invention individually adjusts the opening of each expansion valve in the opening direction until the superheat on the indoor heat exchanger side becomes equal to or less than a fixed value, and then fixes the intake gas superheat of the refrigerant compressor. If there is a certain value or less, the opening of the expansion valves of all the indoor units are corrected and adjusted all at once.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1 is a refrigerant compressor, 2 is an outdoor heat exchanger, 3 is a four-way valve, 4 is an accumulator, 5c and 5d are electronically controlled expansion valves, 6a and 6b are indoor heat exchangers, and 7c and 7d are indoors. Temperature sensors for detecting the outlet temperatures of the heat exchangers 6a and 6b, 8c and 8d
Is a pressure sensor for detecting the outlet pressure of the indoor heat exchangers 6a and 6b, 9a and 9b are controllers for driving the expansion valves 5c and 5d,
10 is a temperature sensor that detects the temperature of the suction gas to the refrigerant compressor 1, 11 is a pressure sensor that detects the pressure of the suction gas to the refrigerant compressor 1, 12 is a signal from the temperature sensor 10 and the pressure sensor 11, The superheat monitor controller sends a monitor signal of the intake gas superheat to the refrigerant compressor 1 to the expansion valve drive controllers 9a and 9b.

FIG. 2 shows controllers 9a and 9b for driving expansion valves 5c and 5d.
It is a flow chart which shows the outline of the procedure controlled by.

Next, the operation will be described.

The changing process and cycle of the refrigerant until the high temperature and high pressure refrigerant gas discharged from the refrigerant compressor 1 is sucked into the refrigerant compressor 1 again during the cooling operation are the same as those in the conventional example, and therefore the description thereof is omitted.

Here, the operation of the expansion valves 5c and 5d of each indoor unit will be described together with the flowchart of FIG.

First, the drive controller 9a, 9b is an indoor heat exchanger 6a obtained from the signals from the temperature sensor 7c.7d and the pressure sensor 8c, 8d,
It is determined whether or not the outlet superheat of 6b is larger than the set value αs (step ST1), and if it is larger, the expansion valves 5c and 5d of each indoor unit are respectively connected to the indoor heat exchanger 6a.
Continue to increase the valve opening individually until the outlet superheat of 6b and 6b becomes less than the set value αs. While the superheat is larger than the set value αs, the valve opening is adjusted only in the direction of increasing it (step ST2). Next, if it is determined in step ST1 that the outlet superheat is less than or equal to the set value αs, then the intake gas superheat of the refrigerant compressor 1 obtained from the signals from the temperature sensor 10 and the pressure sensor 11 is less than the set value βs. It is determined whether or not it is small (step ST3), and if it is determined to be small, the superheat monitor controller 12 causes the drive controller to drive until the suction gas superheat to the refrigerant compressor 1 becomes equal to or greater than the set value βs. 9
A signal is sent to a and 9b, and the valve opening degrees of the expansion valves 5c and 5d are adjusted to be reduced by the same amount (step ST4).

However, the indoor heat exchanger 6a controlled by the expansion valve 5c or 5d
Alternatively, when the outlet superheat of 6b becomes equal to or more than the set value αs in step ST4, only the indoor unit stops the operation of step ST4 and returns to the operation of step ST1.

Next, the indoor heat exchangers 6a and 6b of the respective indoor units
When the outlet superheat of is less than the set value αs and the intake gas superheat to the refrigerant compressor 1 is more than the set value βs, the opening degree of the expansion valves 5c and 5d does not change and the opening degree is kept constant. Yes (step ST5).

By controlling the expansion valves 5c and 5d of each indoor unit by the above method, it is possible to prevent the hunting phenomenon, which has been a serious problem in the past.

That is, first, in the expansion valves 5c and 5d of each indoor unit, the effect of one operating in the opening direction increases the total refrigerant circulation amount and also increases the refrigerant flow rate supplied to the other indoor unit. However, as long as the outlet superheat of the indoor heat exchangers 6a and 6b of the indoor unit is less than or equal to the set value αs and the intake gas superheat to the refrigerant compressor 1 is greater than or equal to the set value βs, the expansion valve 5c and 5d
Since the opening degree of is kept constant in step ST5, it does not trigger hunting.

Next, when the expansion valves 5c and 5d of each indoor unit operate in the closing direction, the suction gas superheat to the refrigerant compressor 1 causes all the indoor units to change at the same opening all at once. Therefore, imbalance of the refrigerant supply amount to each indoor unit is unlikely to occur, which is extremely effective in preventing hunting.

Furthermore, by increasing the outlet superheat setting value αs of the indoor heat exchangers 6a and 6b and decreasing the intake gas superheat setting value βs to the refrigerant compressor 1, as much as possible,
Stability is much higher.

In the above embodiment, the outlet superheats of the indoor heat exchangers 6a and 6b are detected by the temperature sensor and the pressure sensor, but the temperature sensors are attached to the inlets and the outlets of the indoor heat exchangers 6a and 6b, Even if the inlet / outlet temperature difference is detected, the same effect as that of the above-described embodiment can be obtained.

Further, in the above-described embodiment, the case where the number of indoor units is two has been shown, but the number of indoor units may be three or more, and the same effect as that of the above-described embodiment is obtained.

〔The invention's effect〕

As described above, according to the present invention, in the valve opening adjustment of the electronic expansion valve, the detection signal for the opening direction operation and the detection signal for the closing direction operation are obtained from different locations on the indoor heat exchanger side and the refrigerant compressor side. Furthermore, since the opening operation is performed individually in each indoor unit and all indoor units are performed simultaneously in the closing operation, the imbalance of the refrigerant supply amount to each indoor unit is reduced, and stable air without hunting is generated. There is an effect that one that can perform the cycle operation of the harmony device can be obtained.

[Brief description of drawings]

FIG. 1 is a refrigerant system diagram showing a multi-room air conditioner according to an embodiment of the present invention, FIG. 2 is a flow chart showing a control procedure of an expansion valve in an embodiment of the present invention, and FIG. It is a refrigerant system diagram showing a room type air conditioner. 1 is a refrigerant compressor, 2 is an outdoor heat exchanger, 3 is a four-way valve, 4 is an accumulator, 5c and 5d are expansion valves, 6a and 6b are indoor heat exchangers, and 9a and 9b are drive controllers. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A multi-chamber air conditioner comprising a single outdoor unit consisting of a refrigerant compressor, an outdoor heat exchanger and an accumulator, and a plurality of indoor units consisting of an expansion valve and an indoor heat exchanger, Drive for controlling the opening direction of the expansion valve of each indoor unit during cooling operation based on the outlet superheat of each indoor heat exchanger, and also for controlling the closing direction of the expansion valve based on the intake gas superheat of the refrigerant compressor A multi-room air conditioner characterized by having a controller for the air conditioner.