JPH06323673A - Multi-room type air-conditioner - Google Patents

Abstract

PURPOSE:To prevent an abrupt rise of a high pressure side pressure of a refrigerating cycle by making the valve travel of a motor-driven expansion valve corresponding to a stopped room unit larger than that of the valve immediately before it is stopped when any of a plurality of room units which are driven to heat is stopped. CONSTITUTION:When two room units are operated to heat, high pressure gas refrigerant from a compressor 1 is fed from a four-way valve 2 to room side heat exchangers 6, 7 via a tube 8 to motor-driven expansion valves 4, 5 to be reduced under pressure. When the operation of one of the two room units 9 is stopped, a load to the compressor 1 is instantaneously increased, and the high pressure side pressure of a refrigerating cycle is abruptly raised. Then, the valve 4 to the stopped room unit 9 is opened for a predetermined time with its valve travel made larger than that of the valve immediately before stopping. Thus, more refrigerant flows to reduce the load to the compressor 1, thereby preventing abrupt rise of the high pressure side pressure of the cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit, and in particular, the high pressure of a refrigeration cycle when the number of operating indoor units is changed during heating operation. It relates to what prevents a sudden rise in side pressure.

[0002]

2. Description of the Related Art As an example of a method for preventing the pressure on the high-pressure side of a multi-room air conditioner from rising, there is a method described in Japanese Utility Model Laid-Open No. 174954/1982. The cost increased due to the use of valves.

[0003]

However, there is a problem that the high-pressure side pressure of the refrigeration cycle rises sharply when some of the indoor units operating in heating mode are stopped. It had a bad influence on the reliability such as the life of the. An object of the present invention is to prevent a sudden increase in the high-pressure side pressure of the refrigeration cycle when some of the indoor units operating in the heating operation are stopped.

[0004]

The object of the present invention is to provide, immediately before stopping the electric expansion valve corresponding to the stopped indoor unit, when one of the indoor units operating in heating operation is stopped, for example. It is achieved by opening for a certain time larger than the opening degree of the electric expansion valve.

[0005]

When, for example, one of the indoor units operating in heating operation is stopped in the heating operation, the compressor continues the compression operation of the refrigerant. Therefore, the load on the compressor is reduced by the amount of the stop of one indoor unit. It becomes instantaneously large and the pressure on the high pressure side of the refrigeration cycle rises sharply. Therefore, the electric expansion valve corresponding to the stopped indoor unit is opened for a certain period of time larger than the opening degree of the electric expansion valve immediately before the stop. As a result, a large amount of refrigerant flows, the load on the compressor is reduced, and a rapid increase in the pressure on the high-pressure side of the refrigeration cycle can be prevented.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a refrigeration cycle circuit diagram showing an embodiment of the present invention, and FIG. 2 is an operation chart diagram to which the present invention is applied.
1 is a compressor, 2 is a four-way valve for switching between cooling operation and heating operation, 3 is an outdoor heat exchanger, 4, 5 are electric expansion valves, 6, 7
Is a heat exchanger on the indoor side, 8 is a pipe having a low pressure during cooling and a high pressure during heating, and 9 and 10 are indoor units.

In the refrigeration cycle having such a structure,
Well-known cooling and heating operations are performed by switching the four-way valve 2. In the case of operating two heating units, the high-pressure gas refrigerant from the compressor 1 passes from the four-way valve 2 through the pipe 8 to the indoor heat exchanger 6,
From the indoor heat exchanger 7, the electric expansion valve 4 and the electric expansion valve 5 are introduced to reduce the pressure. When the indoor unit 9 is stopped from such operation of two heating units, the compressor 1 continues the compression operation of the refrigerant.
The load on the high pressure side increases momentarily and the high-pressure side pressure of the refrigeration cycle rises rapidly. Therefore, the electric expansion valve 4 corresponding to the stopped indoor unit 9 is opened for a certain period of time larger than the electric expansion valve opening immediately before the stop. As a result, a large amount of refrigerant flows, the load on the compressor 1 is reduced, and a rapid increase in the high-pressure side pressure of the refrigeration cycle is prevented. Further, the installation location of the electric expansion valve can obtain the same effect both in the outdoor unit and in the indoor unit.

Explaining with the operation chart of FIG. 2, when the indoor unit 9 is stopped from the operation of the two heating units, the electric expansion valve 4 is changed from the opening degree of the electric expansion valve immediately before stopping at the same time as the stop command. Open for a certain period of time. The opening degree of the electric expansion valve to be opened at this time may be larger than the opening degree of the electric expansion valve immediately before the stop, or may be opened to the maximum opening degree of the electric expansion valve 4. Further, it is appropriate that the electric expansion valve 4 is widely opened and placed for 15 seconds to 5 minutes after the indoor unit 9 is stopped.

According to the present invention, when some of the indoor units operating in the heating operation are stopped,
Compressor 1 to prevent sudden increase in pressure on the high pressure side of the refrigeration cycle
Improve the reliability such as life of the. In addition, since the electric expansion valve 4 and the electric expansion valve 5 are controlled to be performed, there is an effect that the cost can be increased without increasing the cost. Even if three or more indoor units are connected to the outdoor unit, the same effect can be obtained by performing the same control as in the present invention.

[0011]

According to the present invention, it is possible to prevent a sudden increase in the pressure on the high pressure side of the refrigeration cycle when a plurality of indoor units operating in the heating operation are stopped and to prevent the compressor from increasing. Improves reliability such as life. In addition, since the electric expansion valve is controlled to be performed, there is an effect that the operation can be performed without increasing the cost.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle circuit diagram showing an embodiment of the present invention.

FIG. 2 is an operation chart diagram to which the present invention is applied.

[Explanation of Codes] 1 ... Compressor, 2 ... Four-way valve, 3 ... Outdoor heat exchanger, 4,5
… Electric expansion valves, 6, 7… Indoor heat exchanger, 8… Piping,
9, 10 ... Indoor unit.

Claims (1)

[Claims] 1. An electric expansion valve for adjusting the flow rate of a refrigerant, wherein a plurality of indoor units can be connected to one outdoor unit,
Install the same number or more for the number of connectable indoor units,
In a multi-room air conditioner in which an indoor unit and an electric expansion valve can correspond one-to-one, when a plurality of indoor units are operated for heating and some of them are stopped, the stopped indoor unit The multi-room air conditioner characterized in that the electric expansion valve corresponding to is opened for a fixed time larger than the opening degree of the electric expansion valve immediately before being stopped.