JPS6042854B2 - 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 system that performs heating and cooling by connecting a plurality of indoor units with refrigerant piping to one outdoor unit. Generally, heating operation is performed in this type of air conditioning system. In this case, the on-off valves of the liquid side branch pipe and the gas side branch pipe connected to the indoor unit are connected to the high pressure side, so even if the on-off valves installed in the indoor unit are closed, even if there is a slight leak, refrigerant may leak into this indoor unit. This has the disadvantage that the refrigerant accumulates and reduces the total amount of refrigerant, causing an imbalance, so the branch pipe of the indoor unit that is inactive is connected to the suction side of the compressor to suck out the accumulated liquid.

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 installed between the high-pressure liquid pipe and the low-pressure suction side to store excess 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 the 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, and as the number of indoor units increases, this disadvantage becomes even more serious and becomes a cause of failure. Therefore, in order to solve the above-mentioned drawbacks, the present invention has been made to provide a new air-conditioning and heating system that enables liquid removal without using a solenoid valve even in a system having a refrigerant adjustment tank. An example will be explained 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, which are 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. Numeral 11 is a capillary tube installed in parallel in order to evenly distribute the refrigerant to the outdoor coil 5, and 12 is a check joint pipe connected to a pipe section that is at high pressure during cooling operation and low pressure during heating operation. It is used for checking 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 that becomes high-pressure liquid during cooling and the gas pipe 16 that becomes low-pressure gas.

In other words, this bypass circuit prevents the capillary tubes 22a and 22b, which are properly set during operation of two cooling rooms, from becoming too constricted as a whole system during operation of one room due to their characteristics, and the discharge temperature of the compressor 4 increases. This is a liquid bypass circuit that prevents Reference numeral 29 designates a bypass solenoid valve that opens during heating operation, and extracts liquid refrigerant from the liquid pipe 26, which becomes high-pressure liquid during heating operation, according to the pressure via a pressure adjustment valve 29'' and guides it to the refrigerant adjustment tank 30, where it is stored. Capillary tubes 31 and 32 are provided in the upper and lower parts of the tank 30, respectively, and converge below the bottom of the tank 30 to drain the liquid refrigerant when the solenoid valve 29 is closed.
A first bypass circuit connected to the service valve 15 connected to the second bypass circuit is configured. There is.

In this first bypass circuit, since the pipe line 12 becomes high pressure during cooling, the capillary tube 34 drains liquid from the tank 30 during cooling operation, and the check valve 35 connects the bottom of the tank 30 with the gas that becomes low pressure gas during cooling. It is provided between the pipe 16 and the pipe 16. In addition, when operating one heating room, the solenoid valves 18a, 1
One of the valves 8b, 24a, and 24b is closed, but since all valves are under high pressure, refrigerant leaks and the refrigerant accumulates unnecessarily in the indoor unit on the inactive side, preventing the operation of the refrigeration cycle. Therefore, check valves 36a, 36b,
A second bypass circuit consisting of capillary tubes 37a and 37b is provided. This second bypass circuit further includes check valves 36a, 36b and a capillary tube 37a.
, 37b is provided with a third bypass circuit 38 for applying pressure from the gas pipe 16 which becomes high pressure gas during heating. This third bypass circuit 38 is connected to the check valve 36a.
, 36b and the capillary tubes 37a, 37b. A capillary tube 39 is interposed between the capillary tubes 37a and 37b to reduce the pressure to such an extent that an excessive pressure is not applied and completely prevents liquid removal. Next, the operation and effects of the above configuration will be explained.

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

11 When operating one cooling room...For example, indoor unit 2
In the operation a, the solenoid valves 24b and 18b are closed, and the bypass solenoid valve 27 is opened to prevent the discharge pressure from increasing.

In both of the cooling operations 1 and ii above, the pressure in the pipe line 12 is high, so the first and second bypass circuits do not operate. ■ 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, and the solenoid valves 24a, 24b, 18a, 18b and The valves 29 are each opened.

On the other hand, the pipe line 12 is on the low pressure suction side and serves as a second bypass circuit.
Liquid side branch pipes 23a, 23b through the first bypass circuit
However, the pressure applied by the third bypass circuit 38 prevents the flow, so that there is almost no reduction in capacity. Also, at this time, the refrigerant in the tank 30 is
By adjusting the capillary tubes 31 and 32, no more than necessary is stored. Iv When heating one room...For example, when operating the indoor unit 2a, the solenoid valves 24b and 18b
is closed, and the solenoid valve 29 of the first bypass circuit is opened.

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 bypass circuit includes a third bypass circuit 38.
As the unit 2b continues to operate even though a predetermined pressure is applied thereto, the liquid in the unit 2b is gradually drained, and accumulation of liquid refrigerant is prevented. Further, since this second bypass circuit does not communicate directly with the pipe line 12 but via the tank 30, there is no possibility that the refrigerant in the tank 30 cannot be returned due to the pressure balance. In this way, even if a solenoid valve is not provided in the second bypass circuit to open and close according to the operation, the presence of the third bypass circuit 38 will reduce the capacity during two-chamber operation and prevent the fluid in the stop unit during one-chamber operation. Furthermore, the presence of the refrigerant adjustment tank 30 prevents the liquid from being impossible to drain.

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.Moreover, the second bypass circuit is equipped with a solenoid valve. Since the electric circuit does not use the electric circuit, the electric circuit is simplified and the number of failures is reduced.

[Brief explanation of the drawing]

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, 36a,
36b...Check valve, 37a, 37b...
・Capillary tube, 36a, 36b, 37a, 37
b...Second bypass circuit, 38...
Third bypass circuit.

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 predetermined pressure is applied to the second bypass circuit. A heat pump type multi-room air conditioning/heating device provided with a third bypass circuit connected to a high-pressure gas pipe for applying voltage.