JPS6042853B2 - Heat pump type multi-room air conditioning system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump type multi-room air conditioning and heating system that performs air conditioning and heating by connecting a plurality of indoor units with refrigerant piping to one outdoor unit.

Generally, when performing heating operation in this type of air-conditioning equipment, the on-off valves of the liquid side branch pipe and gas side branch pipe connected to the indoor unit are connected to the high pressure side, so even if the on-off valve installed on the indoor unit that is not in use is closed, there will be a slight However, if there is a leak, refrigerant will accumulate inside this indoor unit, reducing the overall amount of refrigerant and causing an imbalance. It is designed to suck out the liquid that enters it.

On the other hand, in the case of air conditioners with poor air flow, such as ceiling-hanging air conditioners, refrigerant cannot be stored all over the unit when it is not in use, so when a small number of units are in operation, there may be an excess of refrigerant, which may hinder operation. Therefore, a refrigerant adjustment tank is provided between the high-pressure liquid pipe and the low-pressure suction side to store surplus refrigerant when operating a small number of units. In this way, in a system that has the former liquid draining bypass circuit and the latter refrigerant adjustment tank, when both are connected to the compressor suction side, the liquid can be returned smoothly from the refrigerant adjustment tank due to the pressure balance between the two. Therefore, it was necessary to take measures such as interposing a solenoid valve in each bypass circuit and opening the solenoid valve only when necessary to drain the liquid. However, providing individual solenoid valves in the bypass circuit complicates the electrical circuit due to the need for individual control, and as the number of indoor units increases, this disadvantage becomes even greater, and it can easily become a cause of failure. There were some negative effects.
Therefore, in order to solve the above-mentioned drawbacks, the present invention does not use a solenoid valve in the bypass circuit for draining liquid even in a system having a refrigerant adjustment tank, but provides a single solenoid valve in another bypass circuit that acts on this bypass circuit. The invention was developed with the aim of providing a new air-conditioning and heating system that allows liquid to be drained, and one embodiment thereof will be described below with reference to the accompanying drawings.

In the figure, 1 is an outdoor unit, 2a and 2b are indoor units, and 3 is a piping branch unit connected in a ring to form a heat pump type air-conditioning device.

In other words, the outdoor unit 1 includes a compressor 4 and an outdoor coil 5.
, a four-way valve 6, an accumulator 7, a heating capillary tube 8, a check valve 9, and a receiver tank 10 are connected as shown in the figure. In addition, 11 is a capillary tube provided in large numbers in parallel in order to evenly distribute the refrigerant to the outdoor coil 5;
12 is a check joint pipe that communicates with a pipe section that has high pressure during cooling operation and low pressure during heating operation, and is normally used to check operating pressure, but here it is used for draining liquid. . Further, 13, 14, and 15 are service valves connected to the piping branch unit 3.
Next, the piping branch unit 3 and indoor units 2a and 2b will be explained. Reference numeral 16 denotes a gas pipe connected to the service valve 14, which connects to the gas side branch pipe 2 from the branch point 17 through a parallel circuit of electromagnetic valves 18a, 18b and check valves 19a, 19b, respectively.
0a, 20b, and these branch pipes 20a, 20b are connected to the indoor coils 21a, 21a, 21a, 20b of the indoor units 2a, 2b, respectively.
21b. An indoor capillary tube 22 is connected to each coil 21a, 21b of the indoor units 2a, 2b.
A liquid side reversible flow type open/close solenoid valve 24a in the branch unit 3 connected to the liquid side branch pipes 23a and 23b via a and 22b,
24b. The electromagnetic valves 24a and 24b merge at a branch point 25 to form a liquid pipe 26, which is connected to the service valve 13. Reference numeral 27 denotes a bypass electromagnetic valve during single-room cooling operation, which is installed via a capillary tube 28 between the liquid pipe 26, which turns into high-pressure liquid during cooling, and the gas pipe 16, which turns into low-pressure gas.

In other words, this bypass circuit is properly set when operating in two cooling rooms, but when operating in one room, the two capillary tubes 22a and 22b are set too tightly as a whole system due to their characteristics, and the discharge temperature of the compressor 4 increases. This is a liquid bypass circuit that prevents 29 is a bypass solenoid valve that opens during heating operation, and high pressure during heating operation! The liquid refrigerant is extracted from the liquid pipe 26 according to the pressure via the pressure adjustment valve 29'' and guided to the refrigerant adjustment tank 30 for storage. Capillar 3 merges at the 3rd floor and drains the liquid refrigerant when the solenoid valve 29 is closed.
A first bypass circuit is connected to the service valve 15 connected to the conduit 12 via the flow tubes 31 and 32 and the check valve 33.

In this first bypass circuit, since the pipe line 12 is at high pressure during cooling, the capillary tube 34 and check valve 35 are connected to the bottom of the tank 30 and the low pressure gas during cooling. It is provided between the gas pipe 16 and the gas pipe 16. In addition, during single room heating operation, the solenoid valve 18a,
One of the valves 18b, 24a, and 24b is closed, but since all valves are under high pressure, refrigerant leaks, causing unnecessary accumulation of refrigerant in the indoor unit on the inactive side, which interferes with the operation of the refrigeration cycle. Although this may cause trouble, check valves 36a, 36b are installed between the liquid side branch pipes 23a, 23b of each unit 2a, 2b and the upper part of the refrigerant adjustment tank 30.
, a second bypass circuit consisting of capillary tubes 37a and 37b. This second bypass circuit further includes check valves 36a, 36b and a capillary tube 37.
A and 37b are provided with a third bypass circuit 38 that applies pressure from the gas pipe 16 that becomes high-pressure gas during heating. A solenoid valve 39 is interposed in the third bypass circuit 38, which is closed during single-room and double-room cooling operations and during single-room heating operation, and is opened only during two-room heating operations. That is, the operation and effects of the above configuration will be explained as follows.

i During cooling two-room operation...The four-way valve 6 is switched so that the outdoor coil 5 becomes a condenser and the indoor coils 21a and 21b serve as evaporators, and the solenoid valves 24 and 18 are respectively opened.

11 When operating a single cooling room...For example, indoor unit 2
In the operation a, the solenoid valves 24b and 18b are closed, and the bypass solenoid valve 17 is opened to prevent the discharge pressure from increasing.

Note that in both of the above cooling operations 1 and i, the pressure in the pipe line 12 is high, so the first and second bypass circuits do not operate. Furthermore, I, l
In both cases, the liquid side branch pipes 23a, 23b and the gas pipe 16 are connected through the check valves 36a, 36b of the second bypass circuit, and the third bypass circuit 38, but since the solenoid valve 39 is closed, the refrigerant does not flow. There is no flow and ability decline is prevented. 111 During two-room heating operation...The four-way valve 6 is switched so that the outdoor coil 5 becomes the evaporator and the indoor coils 21a and 21b become the condensers. The valves 29 open and close, respectively. On the other hand, the pipe line 12 has a low pressure suction rule, and the liquid side branch pipes 23a and 23b are connected to the low pressure through the second bypass circuit and the first bypass circuit.
At this time, the solenoid valve 39 is opened, so the third bypass circuit 3
The flow of liquid refrigerant is obstructed by the gas pressure applied by 8, and there is almost no reduction in capacity. Also at this time tank 30
The refrigerant is supplied to the pressure regulating valve 29'', capillary tube 31,
With 32 adjustments, no more than necessary will be stored.

When operating a single room with Iv heating...For example, indoor unit 2
In operation a, the solenoid valves 24b and 18b are closed, and the first
The solenoid valve 29 of the bypass circuit opens.

In other words, the pressure regulating valve 29'' senses the increase in high pressure due to a relative decrease in the capacity of the indoor coil 21a that acts as a condenser (compared to the two-chamber operation), and measures the inflow of refrigerant to reduce the refrigerant from the tank 30. It is controlled by storage.On the other hand, inside the indoor unit 2b on the stop side (coil 2
The liquid side branch pipe 2 is installed to prevent refrigerant from accumulating unnecessarily in the inside of the 1b1 pipe 20b, etc. and causing problems in the operation of the refrigeration cycle.
3b communicates with the tank 30 via a second bypass circuit. This second bypass circuit is connected to the inactive unit 2.
Not only unit b but also the unit 2a during operation will be connected to the tank 30, but by setting the capacity of the tank 30 in advance to the capacity of surplus refrigerant during single-room operation, the liquid can be drained to an extreme extent and the capacity can be increased. Never bring down.

In this way, a solenoid valve is provided in each of the second bypass circuits, and the solenoid valve 39 of the third bypass circuit 38 is controlled to open only during two-room heating operation without having to control opening and closing according to the operating state. As a result, many solenoid valves can be omitted, simplifying the electric circuit, preventing a drop in performance when operating two heating rooms, preventing a drop in performance when operating one or two cooling rooms, and draining liquid from the idle unit when operating one heating room. Furthermore, it is possible to prevent the liquid from being impossible to drain due to the presence of the tank 30.

As is clear from the above description, in the air conditioning system of the present invention, the refrigerant adjustment tank in the first bypass circuit does not become impossible to drain even due to the presence of the second bypass circuit. By connecting the second bypass circuit to the tank, the refrigerant is introduced into the tank and then drained, so the flow of the refrigerant is unified and the liquid is reliably drained. Since no solenoid valve is used, the electric circuit is simplified and failures are reduced.

[Brief explanation of drawings]

The drawing is a refrigeration cycle diagram of a heat pump type multi-room air conditioning system according to an embodiment of the present invention. 1...Outdoor unit, 2a, 2b...
Indoor unit, 12...Low pressure suction pipe, 26...
...High pressure liquid pipe, 30 ... Refrigerant adjustment tank,
29, 30, 31, 32, 33...first bypass circuit, 23a, 23b...liquid side branch pipe, 36
a, 36b...Check valve, 37a, 37b...
... Capillary tube, 36a, 36b, 37a,
37b...Second bypass circuit, 38...
...Third bypass circuit, 39... Solenoid valve.

Claims (1)

[Claims] 1. In systems that perform heating and cooling by connecting multiple indoor units with refrigerant piping to one outdoor unit, a first bypass circuit having a refrigerant adjustment tank between the high-pressure liquid pipe and the low-pressure suction pipe during heating operation is provided. A second bypass circuit consisting of a check valve and a capillary tube is provided between the branched liquid side branch pipe of each indoor unit and the refrigerant adjustment tank, and a high pressure A heat pump type multi-room air conditioning/heating device connected to a gas pipe through a second bypass circuit having a single solenoid valve that is opened only during multi-room heating operation.