JPH07294048A - Multi-room split type air conditioner - Google Patents

Abstract

PURPOSE:To eliminate a solenoid valve, etc., for preventing refrigerant liquid reservoir in an indoor unit by providing a plurality of motor operated expansion valves for switching the flows of the refrigerants to a plurality of indoor units in a switching valve unit having a plurality of joints connected to connectors in the plurality of the indoor units and a connector to a service valve. CONSTITUTION:The multi-room split type air conditioner comprises a switching valve unit 13 having motor operated expansion valves 11, 12 and connected to joints 16, 17 of service valves 9, 10 of an outdoor unit 1 to control the flows of the refrigerants to an indoor heat exchanger 7 by the valve 11 and to control the flow of the refrigerants to an indoor heat exchanger 8 by the valve 12. At the time of heating, since the exchangers 7, 8 sides are higher pressure than the valves 11, 12, when an indoor unit 3 is, for example, stopped and the valve 12 is fully closed, liquid refrigerant is stored in the exchanger 8, and insufficient refrigerant occurs, but in order to prevent it, the valve 12 is opened in a predetermined opening to supply a small amount of the refrigerant to the exchanger 3, thereby eliminating the storage of the liquid refrigerant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-chamber separation type air conditioner, and relates to a system suitable for reducing the number of connecting pipes between an indoor unit, an outdoor unit and a switching valve unit and reducing the number of components of the switching valve unit. It is a thing.

[0002]

2. Description of the Related Art A conventional multi-chamber separation type air conditioner uses a solenoid valve or a pressure equalizer for preventing refrigerant from accumulating in a stopped indoor unit, as described in JP-A-61-228273. I used a capillary and a check valve. Also, in connection of piping, it was necessary to connect three systems between the high pressure side, the low pressure side, the pressure equalizing side, the outdoor unit, and the switching valve unit.

[0003]

In the above prior art, a large number of solenoid valves are used in order to prevent refrigerant liquid pooling in the indoor unit, and capillaries for pressure equalization and check valves are used. It was a complicated refrigeration cycle, such as the need for connecting piping between the switching valve units. An object of the present invention is to reduce the size of the switching valve unit by increasing the number of constituent parts of the switching valve unit, to improve the reliability, and to reduce the connecting pipes to improve the work efficiency during installation.

[0004]

The above object is to use an electric expansion valve that is operated by electronic control, and the electric expansion valve for the indoor unit on the stop side is closed during cooling and has a predetermined opening during heating. It can be achieved by

[0005]

When the electric expansion valve for the indoor unit that is stopped is closed during cooling, the refrigerant circuit of this indoor unit becomes substantially the same as the pressure on the suction side of the compressor, and liquid refrigerant does not accumulate. .
Further, during heating, the electric expansion valve on the side of the stopped indoor unit can be set to a predetermined opening degree to prevent a small amount of refrigerant from flowing into the stopped indoor unit to prevent the liquid refrigerant from accumulating.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described. In FIG. 1, 1 is an outdoor unit of a separation type air conditioner, 2 and 3 are indoor units. Further, 4 is a compressor, 5 is a four-way valve, 6 is an outdoor heat exchanger, 9 is a first service valve which is a low pressure side during cooling, and 10 is a second service valve which is a high pressure side during cooling. It is built in. Reference numerals 7 and 8 denote indoor heat exchangers, which are incorporated in the indoor units 2 and 3, respectively. To use it for multiple rooms as shown in FIG.
The switching valve unit 13 composed of 12 electric expansion valves
Joint 16 of service valve 9, second service valve 1
No. 0 joint part 17, and further the switching valve unit 13
And the indoor heat exchangers 7 and 8 are connected by the joint portions 14 and 15,
It is used for air conditioning operation in multiple rooms. In this case, the electric expansion valve 11 controls the flow of the refrigerant to the indoor heat exchanger 7,
The electric expansion valve 12 controls the flow of the refrigerant to the indoor heat exchanger 8. First, if the electric expansion valve 11 or 12 for closing the first service valve 9 to a low pressure during the cooling operation is closed, there is no refrigerant accumulation in the indoor heat exchangers 7 and 8, but during the heating operation, the electric expansion is performed. Since the indoor heat exchanger 7 or 8 side from the valve side 11, 12 is also high in pressure, for example, the indoor unit 3 stops and the electric expansion valve 12
When is completely closed, the liquid refrigerant accumulates in the indoor heat exchanger 8, causing a refrigerant shortage. In order to prevent this, the electric expansion valve 12
Is a predetermined opening degree (it is desirable to set the range from 5% to 30% when fully opened depending on the combination of the indoor unit and the outdoor unit.)
It is opened to open a small amount of refrigerant to the indoor heat exchanger 8 so that liquid refrigerant is not accumulated. The setting of this opening is preferably determined by experiment, that is, the refrigerant flowing to the stop unit side is cooled by natural heat dissipation of the stop unit side refrigerant circuit,
It is best for the electric expansion valve 12 to be in a saturated gas state just corresponding to the pressure at that portion. According to experiments, the opening is preferably 5% to 30% when fully opened. If the opening is smaller than this, the liquid is likely to accumulate in the refrigerant circuit on the stop unit side, and the opening is 30%. With the above, the amount of gas refrigerant flowing to the stop unit side increases, and the heating capacity on the operation unit side decreases to a nonnegligible level. In addition, as a method that can follow ambient conditions, outside temperature, indoor temperature, or
There is a method of detecting the refrigerant pipe temperature of the electric expansion valves 11 and 12 and setting the opening degree according to the temperature. Figure 2
Is a block diagram of the control unit. The switching valve unit control unit is located between the indoor unit control units A and B and the outdoor unit control unit, and respective signals are transmitted from the indoor unit control unit A or B to the outdoor unit control unit. or,
It is sent from the outdoor unit controller to the indoor unit controller A or B. Here, the indoor unit controller A is built in the indoor unit 2, and the indoor unit controller B is built in the indoor unit 3. FIG. 3 is a flowchart showing the operation of the switching valve unit controller. First, when a signal is received from the indoor unit control section A (step 101), it is judged whether cooling or heating (step 10).
2) If it is cooling, fully open the electric expansion valve 11 (step 1
03) Fully close the electric expansion valve 12 (step 104),
If it is heating, fully open the electric expansion valve 11 (step 10
5) Set the electric expansion valve 12 to a predetermined opening. When a signal is received from the indoor unit controller B, the movements of the electric expansion valves 7 and 8 are reversed and the same operation is performed. By performing the refrigeration cycle and control as described above, connection piping for pressure equalization can be eliminated, and at the same time, the refrigeration cycle of the switching valve unit can be simplified to improve reliability and reduce the size of the switching valve unit. You can Further, there is an effect that the work efficiency at the time of installation can be improved. Figure 4
The same effect can be obtained by using two-way valves 18 and 19 in place of the electric expansion valves 11 and 12 of the embodiment of FIG.

[0007]

According to the present invention, an electric expansion valve is used as a switching valve unit, and the electric expansion valve on the indoor unit side that is stopped during cooling is closed to stop the compressor from the suction side. The refrigerant accumulated in the indoor unit inside is collected, and at the time of heating, a small amount of refrigerant is made to flow into the stopped indoor unit by keeping the electric expansion valve on the stopped indoor unit side at a constant opening degree, so that the refrigerant accumulates. The large number of solenoid valves used to prevent refrigerant from accumulating in the indoor unit and the pressure equalizing capillaries and check valves can be eliminated to reduce costs and reduce the number of installation man-hours. There is.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of the present invention.

FIG. 2 is a control block diagram of the present invention.

FIG. 3 is a flowchart showing the operation of the present invention.

FIG. 4 is a refrigeration cycle diagram of the present invention.

[Explanation of symbols]

1 ... Outdoor unit, 2,3 ... Indoor unit, 4 ... Compressor, 5 ... Four way valve, 6 ... Outdoor heat exchanger, 7,8 ... Indoor heat exchanger, 9,10 ... Service valve, 11,12 ... Electric Expansion valve, 13 ... Switching valve unit, 14, 15 ... Joint portion between indoor heat exchanger and switching valve unit, 16, 17 ... Joint portion between service valve and switching valve unit, 18, 19 ... Two-way valve, 20, 21 … Capillary.

Claims (1)

[Claims] 1. A first and second service valve provided in one outdoor unit, a connection part provided in a plurality of indoor units, and a plurality of joint parts respectively connected to the service valve and the connection part. In a multi-chamber separation type air conditioner composed of a switching valve unit, the switching valve unit controls a plurality of electric expansion valves for switching between opening and closing the flow of refrigerant to the plurality of indoor units, and the electric expansion valves. A multi-room separation type air conditioner having an electronic control unit.