JPS6042852B2 - 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 apply high pressure gas from the gas side pipe without intervening a solenoid valve in the bypass circuit for draining liquid from the liquid side branch pipe, the third
At the same time, it was proposed that a bypass circuit be installed to deal with this problem, but in the case where a capillary tube is installed in this bypass circuit and the pressure is lowered to a predetermined level, capillary tubes due to the difference in pressure between multi-room heating and small-room heating may be used. It is very easy to select the tube, and if a solenoid valve is installed to apply gas pressure when heating multiple rooms, it is difficult to select the tube when heating a small number of rooms.
Since the solenoid valve closes, the liquid drainage pressure on the unit side is high when it is in operation, and the liquid drainage pressure on the unit side is low when it is not operating.
There was a drawback that the liquid could not be sufficiently drained from the unit when it was not in use. Therefore, in order to eliminate the above-mentioned drawbacks, the present invention provides a novel heating and cooling system that does not require the provision of individual solenoid valves in the bypass circuit for draining liquid, and can perform optimal control corresponding to the operating state with a single solenoid valve. One embodiment of the invention 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, which are connected in a ring to form a heat pump 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. Further, reference numeral 11 denotes a large number of capillary tubes arranged in parallel in order to evenly distribute the refrigerant to the outdoor coil 5;
Reference numeral 2 denotes 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 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 is connected to a gas side branch pipe 20a from a branch point 17 through a parallel circuit of electromagnetic valves 18a, 18b and check valves 19a, 19b, respectively.
, 20b, and these branch pipes 20a, 20b connect the indoor coils 21a, 21 of the indoor units 2a, 2b, respectively.
connected to b.

The coils 21a, 21b of the indoor units 2a, 2b are connected to the liquid side reversible flow type open/close solenoid valves 24a, 24b in the branch unit 3, which are connected to the liquid side branch pipes 23a, 23b via the indoor side capillary tubes 22a, 22b. Connected. 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. 2
7 is a bypass solenoid valve when operating a single cooling room; It is installed between the liquid pipe 26, which becomes high-pressure liquid during cooling, and the gas pipe 16, which becomes low-pressure gas.

In other words, this bypass circuit prevents the capillary tubes 22a and 22b, which are properly set during two-room cooling operation, from being over-throttled as a whole system during single-room operation due to their characteristics, and the discharge temperature of the compressor 4 increases. This is a liquid bypass circuit that prevents Reference numeral 29 is a bypass solenoid valve that opens during heating operation, and liquid refrigerant is drawn from the liquid pipe 26, which becomes a high-pressure liquid during heating operation, according to the pressure through the pressure adjustment valve 2' and guided to the refrigerant adjustment tank 30 for storage. Capillary tubes 31 and 32 are provided at 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.
The first bypass circuit is connected to the service valve 15 connected to the first bypass circuit.

In addition, in this first bypass circuit, since the pipe line 12 becomes high pressure during cooling, the capillary tube 3 male check valve 35 that drains liquid from the tank 30 during cooling operation 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 a single heating room, the solenoid valves 18a and 18b
, 24a, and 24b, but since all valves are under high pressure, refrigerant leaks and unnecessary refrigerant accumulates in the indoor unit on the idle side, interfering with the operation of the refrigeration cycle. Therefore, each unit 2a, 2b is connected to a second bypass circuit consisting of check valves 36a, 36b, capillary tubes 37a, 37b between the liquid side branch pipes 23a, 23b and the upper part of the refrigerant adjustment tank 30. has been established. This second bypass circuit further includes check valves 36a, 36b and capillary tubes 37a, 3.
A third bypass circuit 38 is provided to apply pressure from the gas pipe 16, which becomes high-pressure gas during heating, between the gas pipe 16 and the gas pipe 7b. This third bypass circuit 38 is connected to the check valves 36a, 36b and the capillary tubes 37a, 37 during single room heating operation.
A capillary tube 39 that reduces the pressure to such an extent that unnecessarily high pressure is not applied between the capillary tube 39 and the capillary tube 39, and a solenoid valve 40 that opens only during two-room heating operation. and is provided. That is, by opening this solenoid valve 40, pressure from the gas pipe 16 is applied to the second bypass circuit, and the liquid side branch pipe 23a is
, 23b to prevent liquid refrigerant from flowing out. Next, the operation and effects of the above configuration will be explained.

(1) During cooling two-room 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 24 and 18 are respectively opened. .

(11) During single-room cooling operation... For example, when operating the indoor unit 2a, the solenoid valves 24b and 18b are closed, and the bypass solenoid valve 27 is opened to prevent the discharge pressure from increasing. .

Note that in both of the above cooling operations (1) and (Ii), the pressure in the pipe line 12 is high, so the first and second bypass circuits do not operate. Similarly, during operation (1) and (Ii), the solenoid valve 40 is closed, and the J liquid side branch pipes 23a, 23b and the gas pipe 16 are communicated through the check valves 36a, 36b1 and the third bypass circuit. However, the presence of the capillary tube 39 obstructs the flow of the refrigerant, so that no significant reduction in capacity occurs.
1 (Iii) Two-room heating operation/
...The outdoor coil 5 becomes the evaporator, and the indoor coil 2
The four-way valve 6 is switched so that 1a and 21b become condensers, and the solenoid valves 24a, 24b, 18a, 18b and the solenoid valve 29 are opened and closed, respectively. On the other hand, the pipe line 12 becomes the low pressure suction side, and the liquid side branch points 23a and 23b are connected to the low pressure through the second bypass circuit and the first bypass circuit, but at this time, the solenoid valve 40 is opened, so the third bypass circuit The pressure applied by 38 substantially obstructs the flow and does not cause any reduction in capacity. Also! At this time, the refrigerant in the tank 30 is not stored more than necessary by adjusting the pressure regulating valve 29'' and the capillary tubes 31 and 32. (Iv) During temporary heating operation...
...For example, when operating the indoor unit 2a, the solenoid valve 24
b, 18b is closed, and one 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. On the other hand, a branch pipe on the liquid side is installed to prevent refrigerant from accumulating unnecessarily in the indoor unit 2b on the stop side (inside the coil 21b1 piping 20b, etc.) and hindering the operation of the refrigeration cycle. 23b communicates with the tank 30 through a second bypass circuit.When the solenoid valve 40 of the third bypass circuit opens, a predetermined pressure reduced by the capillary tube 39 is applied to this bypass circuit. If this applied pressure is set in advance to a level that allows liquid to be drained in the second bypass circuit, as the operation continues, the liquid in the unit 2b will be gradually drained and the accumulation of liquid refrigerant will be prevented. Furthermore, 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 a difference in pressure balance. In addition, this second bypass circuit is connected to the tank 30 not only to the inactive unit 2b but also to the operating unit 2a.
By setting the zero capacity in advance to the capacity of surplus refrigerant during single-room operation, excessive liquid removal will not occur and result in a reduction in capacity. Although a separate solenoid valve is provided in each of the second bypass circuits to control the operation according to the operating state, cooling operation can be performed by opening the solenoid valve 40 of the third bypass circuit 38 only during two-room heating operation. At the same time, the capillary tube 39 is selected to increase the applied pressure during operation in a single heating room, to substantially perform the role of a single solenoid valve 40 corresponding to each conventional solenoid valve, and to control liquid drainage. It is also possible to simplify the electrical circuit and perform optimal control corresponding to each operating state.

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 is not used, the electrical circuit is simplified and failures are reduced.Furthermore, gas pressure can be applied to the liquid draining bypass circuit by the third bypass circuit in two ways: high pressure and low pressure.
Optimal control can be performed depending on the number of operating vehicles and their conditions.

[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, 38...Third
bypass circuit, 39... capillary tube, 40... 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 second bypass circuit consisting of a check valve and a capillary tube is provided between the check valve and the capillary tube. A heat pump type multi-room air-conditioning/heating system that is connected to a high-pressure gas pipe by a third bypass circuit in which a solenoid valve that is opened only when multiple heating units are in operation and a capillary tube are connected in parallel.