JPH06249528A - Air conditioning apparatus - Google Patents

Abstract

PURPOSE:To prevent the lowering of the temperature of air diffused from a room unit during a heating operation when a part of the room unit of a heating operation mode is turned OFF thermally during the simultaneous operation of cooling and heating. CONSTITUTION:Pressure adjusting valves 20A, 20B and 20C are so arranged on branch discharge pipes 10A, 10B and 10C for connecting a discharge pipe 10 to the gas side of outdoor heat exchangers 7A, 7B and 7C to open when a pressure of a gas refrigerant as detected is above a set value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a plurality of indoor units and capable of cooling operation, heating operation and simultaneous cooling / heating operation.

[0002]

2. Description of the Related Art An example of a conventional air conditioner of this type is shown in FIG. In FIG. 2, 1 is a compressor and 10 is a discharge pipe, which is connected to the discharge side of the compressor 1. A suction pipe 11 is connected to the suction side of the compressor 1. 3 is an outdoor heat exchanger, the gas side of which is selectively connected to the discharge pipe 10 or the suction pipe 11 by opening and closing the indoor switching valves 18 and 2. 7A, 7B and 7C are indoor heat exchangers, and their gas sides are the outdoor switching valves 13A, 13B and 13C and the branch suction pipes 11A, 11B and 11 which are respectively installed in the branch discharge pipes 10A, 10B and 10C.
It is selectively connected to the discharge pipe 10 or the suction pipe 11 by opening / closing the outdoor switching valves 8A, 8B, 8C interposed in C.
An outdoor throttling mechanism 4 is arranged on the liquid side of the outdoor heat exchanger 3. Reference numerals 6A, 6B, and 6C denote indoor throttle mechanisms, which are provided on the liquid sides of the indoor heat exchangers 7A, 7B, and 7C, respectively. 12
Is a liquid refrigerant pipe, which connects the liquid side of the outdoor expansion mechanism 4 and the liquid sides of the plurality of indoor expansion mechanisms 6A, 6B, 6C. Reference numeral 15 denotes an outdoor air blower, which allows outdoor air to flow through the outdoor heat exchanger 3.
9A, 9B, 9C are indoor blowers, indoor heat exchangers 7A, 7B,
Allow room air to flow through 7C. A receiver 5 is provided in the liquid refrigerant pipe 12. An accumulator 14 is provided on the suction side of the compressor 1.

Reference numeral O is an outdoor unit, in which a compressor 1, an outdoor switching valve 18, 2, an outdoor heat exchanger 3, an outdoor blower 15, an outdoor throttle mechanism 4, a receiver 5, an accumulator.
Data 14 etc. are built in. A, B, and C are indoor units, respectively. The indoor unit A includes an indoor heat exchanger 7A, an indoor throttle mechanism 6A, and an indoor blower 9A, and an indoor unit B has an indoor heat exchanger 7B and a room. The inner expansion mechanism 6B and the indoor blower 9B are built in, and the indoor unit C contains the indoor heat exchanger 7C, the indoor expansion mechanism 6C, and the indoor blower 9C. Reference numeral 17 is a branch unit, in which the branch discharge pipes 10A, 10B and 10C, the branch suction pipes 11A, 11B and 11C, and the indoor switching valves 13A, 13B and 13C and 8A, 8B and 8C are incorporated.

During cooling operation, for example, indoor units A and B
When the cooling operation is performed and the indoor unit C is stopped, the outdoor expansion mechanism 4 is fully opened, the indoor expansion mechanisms 6A and 6B are set to predetermined opening amounts, and the indoor expansion mechanism 6C is fully closed. It is said that Then, the outdoor switching valve 18 is opened to open the outdoor switching valve 2
The outdoor heat exchanger 3 is communicated with the discharge pipe 10 by closing. Open the indoor switching valves 8A, 8B, and switch the indoor switching valves 13A,
By closing 13B, the indoor heat exchangers 7A and 7B communicate with the suction pipe 11. Then, the indoor switching valves 13C and 8C are closed. Then, the refrigerant gas compressed by the compressor 1 enters the outdoor heat exchanger 3 through the discharge pipe 10 and the outdoor switching valve 18, and radiates heat to the outside air blown by the outdoor blower 15 to condense and liquefy. And becomes a liquid refrigerant. Then
The liquid refrigerant passes through the fully opened outdoor side expansion mechanism 4 and enters the receiver 5, where the gas components are separated. The liquid refrigerant flowing out of the receiver 5 enters the indoor throttle mechanisms 6A and 6B through the liquid refrigerant pipe 12 and is adiabatically expanded by being throttled there to become a gas-liquid two phase. The gas-liquid two-phase refrigerant enters the indoor heat exchangers 7A and 7B, where the indoor air blown by the indoor blowers 9A and 9B is cooled and evaporated and vaporized. This gas refrigerant is sucked into the compressor 1 through the indoor switching valves 8A, 8B, the branch suction pipes 11A, 11B, the suction pipe 11, and the accumulator 14.

During heating operation, for example, indoor units A and B
When the heating operation is performed and the indoor unit C is stopped, the outdoor expansion mechanism 4 and the indoor expansion mechanisms 6A and 6B have predetermined opening degrees. Then, the outdoor switching valve 18 and the indoor switching valves 8A, 8B, 8C and 13C are closed, and the outdoor switching valve 2 and the indoor switching valves 13A and 13B are opened. Thus, the refrigerant discharged from the compressor 1 is condensed and liquefied by the indoor heat exchangers 7A and 7B through the discharge pipe 10, the branch discharge pipes 10A and 10B, the indoor switching valves 13A and 13A, and the indoor throttle mechanism 6A, After being throttled by 6B, it is adiabatically expanded by the outdoor side throttle mechanism 4 via the liquid refrigerant pipe 12 and the receiver 5. Next, after evaporating and evaporating in the outdoor heat exchanger 3, the outdoor switching valve 2, the suction pipe 11, and the accumulator 14 are returned in this order to the compressor 1.

In the simultaneous cooling / heating operation, for example, when the indoor units B and C are in the cooling operation and the indoor unit A is in the heating operation, the outdoor side expansion mechanism 4 and the indoor side expansion mechanism.
6A, 6B, and 6C have predetermined openings. Then, the outdoor switching valve 18 and the indoor switching valves 13A, 8B, 8C are opened, and the outdoor switching valve 2 and the indoor switching valves 8A, 13B, 13C are closed. Thus, a part of the refrigerant discharged from the compressor 1 enters the liquid refrigerant pipe 12 through the discharge pipe 10, the outdoor switching valve 18, the outdoor heat exchanger 3, the outdoor throttle mechanism 4, and the receiver 5. The remaining part enters the liquid refrigerant pipe 12 through the discharge pipe 10, the branch discharge pipe 10A, the indoor side switching valve 13A, the indoor heat exchanger 7A, and the indoor throttle mechanism 6A, and joins with the previously branched refrigerant. Next, this refrigerant is compressed through the indoor expansion mechanisms 6B, 6C, indoor heat exchangers 7B, 7C, indoor switching valves 8B, 8C, branch suction pipes 11B, 11C, suction pipe 11, accumulator 14 in this order. Return to machine 1.

[0007]

In the conventional air conditioner described above, during the simultaneous cooling / heating operation, a part of the indoor units during the heating operation is thermo-off (the indoor unit during the heating operation is installed. When the temperature inside the room rises and reaches the set temperature, the indoor blower of the indoor unit is stopped and the opening degree of the indoor throttling mechanism is set to the minimum opening degree.) Then, the outdoor heat exchanger 3 Since the amount of the refrigerant flowing through the refrigerant increases, the high pressure in the refrigerant circuit decreases, and the condensing pressure in the indoor unit during the heating operation decreases accordingly, and the temperature of the air blown out from this indoor unit decreases. There was a problem.

[0008]

SUMMARY OF THE INVENTION The present invention has been invented to solve the above problems, and its gist is to provide a compressor and a discharge pipe connected to the discharge side of the compressor. And an intake pipe connected to the suction side of the compressor, an outdoor heat exchanger, and an outdoor switching valve that selectively communicates the gas side of the outdoor heat exchanger with the discharge pipe or the intake pipe. The outdoor side throttle mechanism arranged on the liquid side of the outdoor side heat exchanger, the plurality of indoor side heat exchangers, and the gas side of the plurality of indoor side heat exchangers respectively on the discharge pipe or the suction side. An indoor-side switching valve that selectively communicates with the pipe, an indoor-side throttling mechanism that is respectively disposed on the liquid side of the plurality of indoor-side heat exchangers, a liquid side of the outdoor-side throttling mechanism and the plurality of indoor sides It is equipped with liquid refrigerant piping that connects to the liquid side of the throttling mechanism. In an air conditioner that can be operated simultaneously, a pressure regulating valve that detects the pressure of the gas refrigerant in each branch discharge pipe that connects the discharge pipe and the gas side of each indoor heat exchanger and opens when this is above a set value. An air conditioner characterized by being provided with.

[0009]

In the present invention, because of the above configuration, when the pressure of the gas refrigerant flowing into the indoor unit during the heating operation is equal to or higher than the set value, the pressure regulating valve detects this and opens. When it is less than the set value, it is closed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENT One embodiment of the present invention is shown in FIG. The branch discharge pipes 10A, 10B, 10C of the branch unit 17 are equipped with pressure regulating valves 20A, 20B, 20C between the outdoor switching valves 13A, 13B, 13C and the indoor heat exchangers 7A, 7B, 7C, respectively. Has been done. These pressure control valves 20A, 20B, 20C detect the pressure of the refrigerant gas flowing in the branch discharge pipes 10A, 10B, 10C and automatically open when it is above the set value, but close when it is below the set value. Has become.

Thus, when the air conditioner is simultaneously operated for cooling and heating, for example, when the indoor unit A is in cooling operation and the indoor units B and C are in heating operation, part of the gas refrigerant discharged from the compressor 1 Enters the outdoor heat exchanger 3 through the discharge pipe 10 and the outdoor switching valve 18, where it is condensed and liquefied, and then enters the liquid refrigerant pipe 12 through the outdoor throttle mechanism 4. The remaining gas refrigerant enters the indoor heat exchangers 7B, 7C via the discharge pipe 10, the discharge branch pipes 10B, 10C and the indoor side switching valves 13B, 13C and pressure control valves 20B, 20C interposed therein, and here The room air is heated to condense and liquefy. After being squeezed by the indoor expansion mechanisms 6B and 6C, this liquid refrigerant enters the liquid refrigerant pipe 12 and joins with the liquid refrigerant condensed and liquefied in the outdoor heat exchanger 3. The combined liquid refrigerant enters the indoor expansion mechanism 6A, undergoes adiabatic expansion there, and then enters the outdoor heat exchanger 7A, where it evaporates by cooling the indoor air. This gas refrigerant is supplied to the suction branch pipe 11A, the indoor switching valve 8A interposed therein, and the suction pipe 1
First, it is sucked into the compressor 1 through the accumulator 14.

A part of the indoor units B and C during the heating operation during the simultaneous cooling and heating operation, for example, the indoor unit C
When the thermostat is turned off, the indoor blower 9C is stopped, and the indoor throttle mechanism 6C has the minimum opening. Then, the amount of the refrigerant flowing through the indoor unit C decreases, so that the amount of the refrigerant flowing through the indoor heat exchanger 3 increases, and the high pressure in the refrigerant circuit decreases accordingly.

However, the gas refrigerant flowing into the indoor unit B during the heating operation passes through the pressure adjusting valve 20B, and this pressure adjusting valve 20B detects the pressure of the gas refrigerant passing therethrough, and when it is above the set value, it is automatically However, the pressure of the gas refrigerant flowing into the indoor heat exchanger 7B drops below the set value because it automatically closes when the set value is below the set value. Can be blocked. Therefore, since the condensation pressure of the refrigerant in the indoor heat exchanger 7B and the corresponding condensation temperature can be maintained at a predetermined value or higher, the temperature of the indoor air blown out from the indoor unit B can be maintained at a predetermined value or higher.

[001 4]

According to the present invention, the pressure control valve which detects the pressure of the gas refrigerant in the branch discharge pipe connecting the discharge pipe and the gas side of each indoor heat exchanger and opens when the pressure is equal to or higher than the set value. Since the pressure adjusting valve is provided, the pressure of the gas refrigerant flowing into the indoor unit during the heating operation is detected, and the pressure adjusting valve is automatically opened when the pressure is equal to or higher than the set value. As a result, during simultaneous cooling and heating operation of the air conditioner, even if part of the indoor unit during heating operation is thermo-off, the condensation pressure in the indoor heat exchanger of the indoor unit during heating operation will decrease. Since this can be prevented, it is possible to prevent the temperature of the indoor air blown from the indoor heat exchanger from decreasing. Further, since the pressure regulating valve detects the pressure of the gas refrigerant passing therethrough and automatically opens and closes it, there is no need for a signal, a control device, a signal line or the like for controlling this, and therefore the structure is simple and inexpensive. Becomes

[Brief description of drawings]

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

FIG. 2 is a refrigerant circuit diagram of a conventional air conditioner.

[Explanation of symbols]

 1 compressor 10 discharge pipe 11 suction pipe 12 liquid refrigerant pipe O outdoor unit 3 outdoor heat exchanger 2, 18 outdoor switching valve 4 outdoor expansion mechanism A, B, C indoor unit 7A, 7B, 7C indoor heat exchange 6A, 6B, 6C Indoor side throttle mechanism 17 Branch units 20A, 20B, 20C Pressure adjusting valves 8A, 8B, 8C, 13A, 13B, 13C Indoor side switching valves 10A, 10B, 10C Branch discharge pipes 11A, 11B, 11C Branch Suction pipe

Front page continuation (72) Inventor Kazumi Honma 1 Takadaka, Iwazuka-cho, Nakamura-ku, Nagoya-shi, Nagoya Research Laboratory, Mitsubishi Heavy Industries, Ltd. Nagoya Research Institute Co., Ltd.

Claims (1)

[Claims] 1. A compressor, a discharge pipe connected to a discharge side of the compressor, a suction pipe connected to a suction side of the compressor, an outdoor heat exchanger, and the outdoor heat exchanger. Outdoor switching valve for selectively communicating the gas side of the outdoor pipe with the discharge pipe or the intake pipe, an outdoor expansion mechanism arranged on the liquid side of the outdoor heat exchanger, and a plurality of indoor heat exchangers An indoor-side switching valve for selectively communicating the gas side of the plurality of indoor-side heat exchangers with the discharge pipe or the suction pipe, and the liquid-side of the plurality of indoor-side heat exchangers, respectively. And a liquid refrigerant pipe connecting the liquid side of the outdoor side throttling mechanism and the liquid side of the plurality of indoor side throttling mechanisms, and cooling operation, heating operation, and cooling / heating simultaneous operation can be performed. In the air conditioner, the branch discharge pipe connecting the discharge pipe with the gas side of each indoor heat exchanger An air conditioner comprising a pressure adjusting valve that detects the pressure of each gas refrigerant and opens when the pressure exceeds a set value.