JPH0451319Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to a multi-type air conditioner in which multiple indoor units are connected to one outdoor unit, and in particular, This invention relates to an improvement in a refrigerant flow control structure to an indoor heat exchanger.

(Prior art) An air conditioner is constructed from one outdoor unit and a plurality of indoor units, and the indoor heat exchangers provided in each of the above-mentioned indoor units are provided in each air-conditioned room, and these are operated simultaneously or independently. There is a tendency for multi-type air conditioners that can be operated to condition air to be used frequently.

Conventionally, this type of air conditioner has a refrigeration cycle configured as shown in FIG. That is,
In the figure, 1 is a compressor, 2 is a four-way switching valve, 3 is an outdoor heat exchanger, 4 is a parallel circuit of a heating expansion valve 5 and a check valve 6, 7a and 7b are reversible solenoid valves, and 8a and 8b are first and second capillary tubes that are pressure reducing devices;
9a and 9b are first and second indoor heat exchangers; 10
a and 10b are reversible solenoid valves, and 11 is an accumulator. Note that from the reversible solenoid valve 7a to the first capillary tube 8a and the first indoor heat exchanger 9
a, connected in series to the branch refrigerant pipe Pa up to the reversible solenoid valve 10a, from the reversible solenoid valve 7b to the second capillary tube 8b, and the second indoor heat exchanger 9;
b, connected in series to the branch refrigerant pipe Pb up to the reversible solenoid valve 10b. The above-mentioned branch refrigerant pipes Pa and Pb are branched from a refrigerant pipe P that communicates with other refrigeration cycle components and are arranged in parallel.

Also, as shown in the figure, a compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3, a parallel circuit 4, and an accumulator 11 are housed in an outdoor unit, and first and second capillary tubes 8a and 8b are connected to each other. The first and second indoor heat exchangers 9a and 9b are each accommodated in a plurality of indoor units, and each reversible solenoid valve 7
a, 7b and 10a, 10b are accommodated in branch units, respectively.

Thus, by driving the compressor 1 and switching the four-way switching valve 2 in a predetermined direction, cooling operation or heating operation can be performed. In the figure, cooling operation is performed by conducting the refrigerant in the direction of the solid line arrow, and heating operation is performed by conducting the refrigerant in the direction of the broken line arrow. Furthermore, when both the reversible solenoid valves 7a, 10a or 7b, 10b are controlled to open and close, the first
Each air-conditioned room equipped with the second indoor heat exchangers 9a and 9b can be heated and cooled simultaneously or independently.

(Problems to be solved by the invention) In this way, for the air conditioning operation control, which is the heating and cooling operation control of each indoor unit, each reversible solenoid valve 7a,
7b, 10a, and 10b are selected and the opening/closing operation is performed. In other words, in this type of system, since the control is on whether or not the refrigerant is allowed to flow through the indoor units, the air conditioning function of each indoor unit is completely turned on and off, leading to extreme temperature changes. Therefore, there is a problem that detailed and comfortable air conditioning cannot be achieved.

The present invention was developed in view of the above-mentioned circumstances, and its purpose is to provide a multi-type air conditioner that can provide air conditioning while ensuring comfort in each indoor unit. It is something.

[Structure of the idea]

(Means for Solving the Problems) In other words, the present invention connects the indoor heat exchangers of a plurality of indoor units in parallel to the compressor and outdoor heat exchanger provided in the outdoor unit through branch refrigerant pipes. In those connected to form a refrigeration cycle, the compressor is of a variable capacity type that controls the operating frequency according to the total required capacity from each indoor unit, and the compressor is of a variable capacity type that controls the operating frequency according to the total required capacity from each indoor unit. The branch refrigerant pipe is equipped with a flow control valve that opens only the required capacity of each indoor heat exchanger according to a command from the indoor unit, and a
A cooling expansion valve whose throttling amount is controlled according to the outlet refrigerant temperature of each indoor heat exchanger for reducing the pressure of the liquid refrigerant whose flow rate is controlled by the flow rate control valve is connected in series. It is a multi-type air conditioner.

(Function) By configuring the refrigeration cycle in this way, the capacity can be changed in each indoor unit, allowing comfortable air conditioning.

(Example) Hereinafter, an example of the present invention will be described based on FIG. 1. In the figure, 15 is a so-called inverter type compressor, which is a variable capacity type that controls the rotation frequency.
2 is a four-way switching valve, 3 is an outdoor heat exchanger, 4 is a parallel circuit of a heating expansion valve 5 and a check valve 6, 16a, 1
Reference numeral 6b denotes first and second flow control valves, which are controlled by a pulse motor or the like having linear flow characteristics. 17a and 17b are parallel circuits of first and second cooling expansion valves 18a and 18b and check valves 19a and 19b, 9a and 9b are first and second indoor heat exchangers, and 10a and 10b are reversible circuits. The electromagnetic valve 11 is an accumulator. Note that there is a branch refrigerant pipe from the first flow control valve 16a to the parallel circuit 17a, the first indoor heat exchanger 9a, and the reversible solenoid valve 10a.
The second flow control valve 1 is connected in series to Pa.
6b to the parallel circuit 17b, the second indoor heat exchanger 9b, and the reversible solenoid valve 10b are connected in series to the branch refrigerant pipe Pb. The above-mentioned branch refrigerant pipes Pa and Pb are branched from a refrigerant pipe P communicating with other refrigeration cycle components and are arranged in parallel. The heat sensitive parts 20a, 20b of the first and second cooling expansion valves 18a, 18b are as follows:
The above reversible solenoid valve 1 for branch refrigerant pipes Pa and Pb, respectively
It is attached near 0a and 10b. As shown in the figure, the compressor 1, the four-way switching valve 2, the outdoor heat exchanger 3, the parallel circuit 4, and the accumulator 11 are housed in the outdoor unit, and the first and second indoor heat exchangers 9a, 9b are housed in a plurality of indoor units, respectively, and are connected to the first and second flow control valves 16a and 16.
b, parallel circuits 17a, 17b and reversible solenoid valve 1
0a and 10b are each housed in a branch unit.

Thus, by driving the compressor 15 and switching the four-way switching valve 2 in a predetermined direction, cooling operation or heating operation can be performed. In the figure, cooling operation is performed by conducting the refrigerant in the direction of the solid line arrow, and heating operation is performed by conducting the refrigerant in the direction of the broken line arrow.

To explain, during cooling operation, the refrigerant liquefied in the outdoor unit is sent to the branch unit. Here, the first and second flow control valves 16a, 16b
is controlled in accordance with a command from the indoor unit to supply refrigerant in an amount corresponding to the required capacity of the first and second indoor heat exchangers 9a and 9b, and is set in advance according to the required capacity. Each flow control valve 16a, 16
Since b is a valve driven by a pulse motor or the like, the flow rate characteristics can be varied linearly. Furthermore, the refrigerant is guided to first and second expansion valves 18a and 18b. Here, the flow rate control valves 16a, 16
The liquid refrigerant whose flow rate is controlled in step b is depressurized, and therefore the amount of throttling is controlled according to the outlet refrigerant temperature of each indoor heat exchanger 9a, 9b. Therefore, the indoor heat exchangers 9a, each acting as an evaporator,
The degree of superheating of 9b is controlled. Furthermore, the capacity of the compressor 15 is controlled by an inverter in accordance with the total capacity required of the indoor unit.

In this way, the flow control valves 16a, 16b
The opening degree is set in advance according to the request from the indoor unit, and if the required capacity from the indoor unit changes, the opening degree can be controlled according to that change. Therefore, it is possible to construct a multi-type air conditioner by freely selecting and combining indoor units with different capacities. Further, the pressure reduction control of the refrigerant is performed by each expansion valve 8a, 18b, and the flow rate control valve 16a, 1
Since 6b only controls the flow rate, these controls (software) are simple.

The same holds true during heating operation, where refrigerant is sent from the outdoor unit to the indoor unit. Furthermore, in the branch unit, each flow rate control valve 16a, 16b is set to an opening degree corresponding to the required capacity of the first and second indoor heat exchangers 9a, 9b to return the refrigerant to the outdoor unit, thereby achieving comfortable heating operation. .

[Effect of idea]

As explained above, the present invention has a variable capacity compressor that controls the operating frequency according to the total required capacity from multiple indoor units, and a variable capacity compressor that controls the operating frequency according to the total required capacity from multiple indoor units. The air conditioner has a flow control valve that opens according to its capacity, and during cooling operation, the amount of throttling is controlled according to the outlet refrigerant temperature of each indoor heat exchanger to reduce the pressure of the liquid refrigerant whose flow rate is controlled by this flow control valve. Since it is equipped with an expansion valve, air conditioning capacity can be controlled in each indoor unit.
In addition to providing comfortable air conditioning, the capacity of the indoor unit can be freely set, resulting in the effect of providing optimal air conditioning for each room.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a refrigeration cycle of a multi-type air conditioner showing an embodiment of the present invention, and FIG. 2 is a block diagram of a refrigeration cycle of a multi-type air conditioner showing a conventional example of the present invention. 15...Compressor, 3...Outdoor heat exchanger, 9
a, 9b...(first, second) indoor heat exchanger,
Pa, Pb... Branch refrigerant pipe, 16a, 16b...
(first, second) flow control valves, 18a, 18b...
...(For first and second cooling) expansion valve.

Claims (1)

[Scope of utility model registration request] In the compressor and outdoor heat exchanger provided in the outdoor unit, the indoor heat exchangers of a plurality of indoor units are connected in parallel through branch refrigerant pipes to form a refrigeration cycle, and the compressor is connected to the outdoor heat exchanger. It is a variable capacity type that controls the operating frequency according to the total required capacity from each indoor unit, and the liquid side branch refrigerant pipe of the indoor heat exchanger in each indoor unit has a A flow control valve that opens only the required capacity of the heat exchanger, and a throttle amount that is adjusted according to the outlet refrigerant temperature of each indoor heat exchanger to reduce the pressure of the liquid refrigerant whose flow rate is controlled by this flow control valve during cooling operation. A multi-type air conditioner characterized in that a cooling expansion valve and a cooling expansion valve that are controlled are connected in series.