JPH03236555A - Multi air-conditioner - Google Patents

Abstract

PURPOSE:To enable high pressure cut of a refrigerant without repeating drive and stop of a compressor by providing a control device to open the on-off valve of an indoor unit under a stop when a detecting value from a pressure sensor is inputted and the detecting value exceeds a set pressure. CONSTITUTION:When heating operation is started, a compressor 6 is started to run by means of a signal from a control device 5, a refrigerant is started to flow to only an indoor unit 3a, and the delivery pressure of a refrigerant with the aid of the compressor 6 is increased. The delivery pressure is detected by a pressure sensor 11, and when the delivery pressure exceeds a set upper limit value, a signal is inputted from the pressure sensor 11 to the control device 5. The control device 5 causes refrigerant to flow to on-off valves 12b and 12c located in refrigerant pipings 4b and 4c of indoor units 3b and 3c the operation of which is stopped and the indoor units 3b and 3c operation of which is stopped with flow rate regulating valves 13b and 13c opened. This constitution prevents a delivery refrigerant pressure from exceeding an upper limit delivery pressure.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) The present invention relates to a multi-air conditioner, and in particular, the present invention relates to a multi-air conditioner, and in particular, by adjusting the discharge pressure of refrigerant sent to each indoor unit during heating operation. Regarding a multi-air conditioner with improved compressor durability.

(Prior Art) Fig. 2 is an In diagram of a conventional multi-air conditioner. , or configured to operate independently.

This outdoor unit b is installed outdoors, and includes a compressor d and an outdoor heat exchanger e for configuring a refrigeration cycle.
, an expansion valve f, a four-way valve g, a liquid receiving tank h, etc. are accommodated therein. This pressure add compresses the gasified refrigerant to a high temperature and high pressure, so that sufficient discharge pressure can be exerted even if the units CI+C2+C3 are operated simultaneously in each room.

Moreover, the outdoor heat exchanger e also has a sufficient heat exchange function.

On the other hand, the indoor units C+ + C2+ C3, which are installed in parallel with the outdoor unit b, are installed at various locations indoors as necessary, and are used to condition the indoor air using an indoor heat exchanger (not shown) installed inside. is going on.

Then, outdoor unit b and each indoor unit CI + C
2+ C3 means three refrigerant pipes It, '2+
It is connected by 13. Also, each refrigerant pipe f, li, f
3 includes an on-off valve Jl+'2+J3 that opens and closes the refrigerant flow path, and a flow rate adjustment valve that adjusts the flow rate of the refrigerant. ks
are provided respectively, and each refrigerant pipe it, f
2+! 3 is an expansion valve for cooling operation, 1), , J! 2
．． J? , and check valves m 1 + m 21 m s are provided in parallel. Therefore, indoor unit C1
+ C21Cs individually stops or starts operation or finely adjusts the temperature by opening and closing these various valves or adjusting the flow rate of the refrigerant by the control unit n.

(Problem to be Solved by the Invention) In the multi-air conditioner described above, for example, if two of the three indoor units are stopped and only one indoor unit is operated for heating. The discharge pressure of the compressor will be concentrated in one indoor unit, and there is a possibility that the discharge pressure of the refrigerant will increase and the compressor will be damaged. Therefore, an upper limit of the discharge pressure has been set, and when the discharge pressure exceeds the set pressure, the operation of the compressor is stopped to prevent the pressure from increasing and protect the compressor. Then, when the pressure decreases, the compressor starts operating again, and this process is repeated thereafter. Pressure like this! By stopping fmR, high pressure cut operation was performed to prevent the refrigerant discharge pressure from becoming higher than necessary.

However, in such high-pressure cut operation, the compressor is repeatedly driven and stopped, which reduces the durability of the compressor and causes breakdowns.

Therefore, the present invention has been made to effectively solve these problems, and provides a multi-air conditioner that makes it possible to perform high-pressure cutting of refrigerant without repeatedly driving and stopping the pressure and AVL. It is.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention connects a plurality of indoor units to an outdoor unit in parallel, and provides a multi-unit system in which an on-off valve is provided at the refrigerant inlet/outlet. In an air conditioner, a pressure sensor is provided in the outdoor unit to detect the discharge refrigerant pressure, and the on-off valve of the indoor unit that is in operation is opened, the on-off valve of the indoor unit that is out of operation is closed, and the pressure sensor detects the pressure sensor. The control device is configured to include a control device that opens the on-off valve of the stopped indoor unit when a value is input and the detected value exceeds a set pressure.

(Function) During heating operation, the pressure of the refrigerant discharged from the compressor is measured by the pressure sensor installed on the discharge side of the pressure Wi machine, and if the pressure exceeds the set pressure, the signal is input from the pressure sensor to the control device. . When the signal is input, the control device opens the on-off valve of the stopped indoor unit 7 to release the discharged gas to the stopped indoor unit, thereby lowering the discharge refrigerant pressure. Further, if this state continues for a while, the discharge pressure will further decrease and the heating capacity will also decrease, so a lower limit pressure setting value is provided. When the pressure falls below the set lower limit pressure, the opened on-off valve is closed again, causing the pressure to rise again. Thereafter, by repeating this, the discharge pressure can be maintained within a certain range without stopping the pressure WJ#1g.

<Example> Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of a multi-air conditioner according to the present invention. As shown in the figure, this multi air conditioner 1 includes one outdoor unit 2 and three indoor units 3a, 3b, 3c.
are installed in parallel.

The indoor units 3a, 3b, 3c and the outdoor unit 2 are connected by three refrigerant pipes 4a, 4b, 4c to form a refrigeration cycle, which is controlled by a control device 5. Note that this multi-air conditioner 1 has a four-way valve provided in the outdoor unit 2, and employs a shi-tobong method in which the four-way valve is reversed to change the flow of refrigerant.

These indoor units 3a, 3b, and 3c are each installed at various locations indoors, and each unit includes an indoor heat exchanger (not shown) that cools and heats the room by circulating indoor air and exchanging heat with the indoor air. ) are accommodated. On the other hand, the outdoor unit 2 is installed outdoors, and includes a compressor 6 that compresses the refrigerant to high temperature and high pressure and has sufficient discharge capacity even when the three indoor units 1a, 3b, and 3c are operated simultaneously. ,
Outdoor heat exchanger t1 for condensing or evaporating refrigerant! ! !
It mainly houses an expansion valve 8 for adjusting the refrigerant pressure, a four-way valve for switching the flow of the refrigerant, a refrigerant tank IO for temporarily storing the refrigerant, and a pressure sensor 11 for measuring the discharge refrigerant pressure. has been done. This pressure sensor 11 has a compression fi
7 discharge (provided in the RIJ to measure the discharge pressure of the compressed fi6 discharge gas, and also detect the pressure range of the upper limit refrigerant pressure when the discharge pressure becomes high pressure and the lower limit refrigerant pressure when the discharge pressure becomes low pressure. , the detected value is input to the control device 5.

Also, an outdoor unit 2 and an indoor unit 3a.

3b and 3c are provided with refrigerant pipes 4a, 4b, and 4c that connect them in parallel, respectively. A refrigerant pipe 4a connects the indoor units 3a, 3b, 3c and the compressor 6 in the outdoor unit 2.

4b, 4c have on-off valves 12a, 1 that regulate the flow of refrigerant.
2b and 12c are provided, respectively. This on-off valve 1
2a, 12b, and 12c are composed of electromagnetic valves, etc., and are opened and closed to regulate the flow of refrigerant, respectively, in response to a signal from the control device 5. In addition, during heating operation, the flow rate of liquid refrigerant flowing from the indoor units 3a, 3b, 3c is adjusted in the refrigerant pipes 4a, 4b, 4c that connect the indoor units 3a, 3b, 3c and the refrigerant tank 10 in the outdoor unit 2. Flow rate adjustment valves 13a, 13b,
13c is provided. This original adjustment valve 13a, 13
b 13c is composed of a pulse motor valve, etc., and is a 3L valve which is controlled by the control device 5 and the flow rate of the refrigerant is individually adjusted as described above. Furthermore, the indoor unit)-3a31), 3C and the flow rate adjustment valves 13a, 13b
, 13c is the expansion of refrigerant for cooling operation (F 15
a.

15b and 15c are provided, and each of the force expansion valves 14a, 14b, and 14'c for cooling operation has check valves 15a and 15b that serve as a bypass flow path for refrigerant during heating operation.
, 15c are provided in parallel.

Next, the operation of the present invention will be explained.

For example, when performing a heating operation using only the indoor unit 3a, when the operation mode of the indoor unit 3a is set to heating operation and the heating operation is started, a signal from the control device 5 causes other indoor units that are not operating to 111) Close: #12b, 12c and flow regulating valve 13b to stop the flow of refrigerant to 3b, 3c.

13c is closed, the compressor 6 begins to drive, and the refrigerant begins to flow only to the indoor unit 3a.

To explain this in detail, the refrigerant compressed to high temperature and high pressure by the compressor 6 is equally distributed to the refrigerant pipes 4a + 4b and 4c, but when the on-off valves 12b and 12c of the refrigerant pipes 4b and 4c are closed. In this state, the refrigerant is not purified to the indoor units 3b and 3c, but is sent to the indoor unit 3a through only the refrigerant pipe 4a. The refrigerant sent to the indoor unit 3a emits heat indoors and condenses in the indoor heat exchanger provided in the indoor unit 3a, and is then transferred to the other refrigerant pipe 4a.
The liquid then passes through the check valve 15a and the flow rate adjustment valve 13a and is temporarily stored in the liquid receiving tank 10 in the outdoor unit 2. The stored high-pressure liquid refrigerant then passes through an expansion valve, becomes low-pressure, is sent to the outdoor heat exchanger 7, absorbs outdoor heat, becomes gasified, is sucked into the pressure ta machine 6, and is circulated again to the indoor unit 3a. will be done.

If this operation continues for a while, the heating load on the indoor unit 3a will decrease, and the discharge pressure of the refrigerant from the compressor 6 will increase. This discharge pressure is the discharge of compression R6 (III!
A control device 5 into which the detected value from the pressure sensor 11 is inputted is detected by the pressure sensor 11 provided in the pressure sensor 11, and when the set upper limit discharge pressure is exceeded, a signal is inputted from the pressure sensor 11 to the control device 5. The on-off valves 12b and 12c and the flow rate adjustment valve 13b are provided in the refrigerant pipes 4b and 4c of the indoor units 3b and 3c whose operation is stopped.

Indoor unit 3b which has stopped operation with 13c open;
3c, the discharge refrigerant pressure gradually decreases without exceeding the upper limit discharge pressure, and when this discharge pressure gradually decreases to below the set lower limit discharge pressure. A detected value is input from the pressure sensor 11 to the control device 5. The 11J911 device 5 inputting this detected value from the pressure sensor 11 again closes the on-off valves 12b, 12.
By closing the flow control valves 13b and 13c, the flow of refrigerant to the indoor units 3b and 3c is stopped.

In this way, the detected values from the pressure and force sensor 11 are transmitted to the control device 5.
This is because the control device 5 adjusts the discharge refrigerant pressure to always be within the set pressure range by repeatedly opening and closing the on-off valve and flow rate adjustment valve of the indoor unit that is stopped according to the input. , The frequency of driving and stopping the compressor is significantly reduced, resulting in fewer failures.

[Effect of the invention] As described above, the present invention has the following excellent effects.

(1) Since the frequency of driving and stopping the pressure iaR is greatly reduced, failures are reduced and the reliability of the compressor is improved.

(2) Since high-temperature, high-pressure refrigerant is flowing through the stopped indoor unit, when heating the stopped indoor unit, the heating operation starts quickly, improving comfort.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a multi-air conditioner showing an embodiment of the present invention, and FIG. 2 is a schematic diagram of a conventional multi-air conditioner air conditioner. In the figure, 1 is a multi air conditioner, 2 is an outdoor unit, 3a,
3b, 3c are indoor units, 5 is a control device, 11 is a pressure sensor, 12a, 12b. 12c is an on-off valve. Fountain Gin @ Figure 1

Claims (1)

[Claims] 1. In a multi-air conditioner in which multiple indoor units are connected in parallel to an outdoor unit and an on-off valve is provided at the refrigerant inlet/outlet, a pressure sensor installed in the outdoor unit to detect the discharge refrigerant pressure and a When the on-off valve of the indoor unit is opened and the on-off valve of the stopped indoor unit is closed, and the detected value of the pressure sensor is input, and the detected value exceeds the set pressure, the stopped indoor unit A multi-air conditioner characterized by being equipped with a control device that opens an on-off valve.