JPS635653B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump type multi-room air-conditioning/heating system in which a plurality of indoor units are connected by refrigerant piping to one outdoor unit to perform air-conditioning and heating.

In general, in this type of air conditioning system, the amount of refrigerant required for multi-room operation and small-room operation is different, so surplus refrigerant is bypassed during small-room operation, or
Measures are being taken, such as storing the refrigerant in a designated refrigerant storage tank. In other words, during cooling operation, the liquid pipes and gas pipes that connect outdoor and indoor units are at high and low pressure, so by providing a bypass between them, the transition from multi-room operation to small-room operation is performed smoothly. . On the other hand, during heating operation, both the liquid pipe and the gas pipe before and after the indoor coil of the indoor unit are at high pressure because there is little pressure difference, and the bypass for changing the operating state cannot be used. Therefore, it was necessary to use a pressure regulating valve to control the amount of refrigerant to be returned to the low pressure side while storing surplus refrigerant in the tank. Then,
Due to the delay in the operation of the pressure regulating valve in response to a change in the pressure within the system during a change in operation, a rise in high pressure occurred, which sometimes resulted in the inability to operate due to the operation of the high pressure switch.

The present invention has been made to overcome these drawbacks, 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, which are connected in a ring to form a heat pump air-conditioning system.
That is, a compressor 4, 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 to the outdoor unit 1 as shown in the figure. Reference numeral 11 denotes a large number of capillary tubes arranged in parallel to evenly distribute the refrigerant to the outdoor coil 5. Reference numeral 12 denotes a check joint conduit that communicates with a pipe section that is at high pressure during cooling operation and at low pressure during heating operation. It is used for checking operating pressure, but here it is used for draining liquid. 13, 14, 15 more
is a service valve connected to the piping branch unit 3. Next, the piping branch unit 3 and indoor units 2a and 2b will be explained. 16 is a gas pipe connected to the service valve 14, and from the branch point 17 are connected electromagnetic valves 18a, 18b and check valves 19a, 1, respectively.
Gas side branch pipes 20a, 2 through parallel circuit 9b
0b, these gas side branch pipes 20a, 20
b is connected to the indoor coils 21a and 21b of the indoor units 2a and 2b, respectively. The coils 21a, 21b of the indoor units 2a, 2b are connected to the liquid side branch pipes 23a, 23b via the indoor capillary tubes 22a, 22b, and the liquid side reversible flow type open/close solenoid valves 24a, 24b in the branch unit 3
connected to. 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 through which high-pressure liquid passes during cooling and the gas pipe 16 through which low-pressure gas passes. That is,
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, and the discharge temperature of the compressor 4 from rising. This is a liquid bypass circuit. Reference numeral 29 denotes a bypass solenoid valve that is opened during heating operation, and includes a pressure regulating valve 30 that adjusts the degree of opening, that is, the amount of refrigerant to be bypassed, according to the pressure, a refrigerant regulating tank 31 that stores refrigerant, and an air layer in this tank 31. A parallel circuit of the gas side capillary tube 32 communicating with the liquid layer section and a liquid side capillary tube 33 communicating with the liquid layer section, and a series circuit with the check valve 34 are formed, and one end of this circuit is connected to the high pressure liquid during heating operation. The first bypass circuit is connected to the liquid pipe 26 through which the pump passes, and the other end is connected to the service valve 15 connected to the pipe line 12 on the low-pressure suction side, thereby forming a first bypass circuit. That is, when the valve 29 is opened, the pressure regulating valve 30 senses the pressure from the liquid pipe 26 and adjusts its opening while drawing the liquid refrigerant from the liquid pipe 26 and guiding it to the tank 31 for storage. The amount of refrigerant in the tank 31 is adjusted by the gas side capillary tube 32 for removing the gas in the tank 31, that is, the amount of stored liquid refrigerant is controlled. The refrigerant is gradually returned to the low pressure side via 15. The first bypass circuit has a capillary tube 35 that drains liquid from the tank 31 during cooling operation because the pressure in the pipe line 12 becomes high during cooling, and a check valve 36 that connects the bottom of the tank 31 to the low pressure side during cooling. It is provided between the gas pipe 16 and the gas pipe 16.

Also, when operating a single heating room, the solenoid valve 18
One of a, 18b, 24a, and 24b is closed, but since all of the valves are under high pressure, refrigerant leaks, causing unnecessary accumulation of refrigerant in the indoor unit on the idle side, causing damage to the refrigeration cycle. This may interfere with operation, but for this reason each unit 2
Check valves 37a, 37b are installed between the liquid side branch pipes 23a, 23b of a, 2b and the upper part of the refrigerant adjustment tank 31.
A second tube consisting of capillary tubes 38a and 38b
A bypass circuit is provided. This second bypass circuit is further provided with a third bypass circuit that applies pressure from the gas pipe 16, which becomes high-pressure gas during heating, between the check valves 37a, 37b and the capillary tubes 38a, 38b.
A bypass circuit 39 is provided. This third
A capillary tube 40 is interposed in the bypass circuit 39 to reduce the pressure between the check valve 37 and the capillary tube 38 to such an extent that excessive pressure is not applied between the check valve 37 and the capillary tube 38 and completely prevents liquid drainage.

On the other hand, the gas side branch pipes 20a and 20b are connected to the solenoid valve 4.
1, and this solenoid valve 41 is opened for a predetermined time (several tens of seconds) when switching from two-room heating operation to one-room heating operation. That is, when the pressure and refrigerant amount in the system are working in a normal state in two-chamber operation, a sudden change in load occurs when the system shifts to single-chamber operation, and the pressure regulating valve 30 is unable to follow this immediately. Immediately after the transition, the solenoid valve 41 opens, and the refrigerant circulates not only to the unit that should be operated, but also to the unit that should be stopped, and after the amount of refrigerant decreases, the solenoid valve 41 opens.
1 is closed, thus alleviating sudden fluctuations and allowing the pressure regulating valve 30 to follow suit, preventing a rise in high pressure due to transition.

Next, the operation of the above configuration will be explained according to the operating state.

(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 become an evaporator, and the solenoid valves 24a and 2
4b, 18a, and 18b are opened respectively.

(ii) When operating a single cooling room... For example, when operating the indoor unit 2a, the solenoid valves 24a and 18b are closed, and the bypass solenoid valve 27 is opened to prevent the discharge pressure from increasing. In both of the above cooling operations (i) and (ii), the pressure in the pipe line 12 is high, so the first and second bypass circuits do not operate.

(iii) 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 and 2
4b, 18a, 18b and the solenoid valve 29 are opened and closed, respectively. On the other hand, the pipe line 12 is on the low pressure suction side, 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, but the flow is obstructed by the pressure applied by the third bypass circuit 39. Almost no decrease occurs.

(iv) When operating a heating room... For example, when the indoor unit 2a is operating, the solenoid valves 24b and 18b are closed, and the solenoid valve 29 of the first bypass circuit is opened. That is, the pressure regulating valve 30 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 and controls the flow of refrigerant into the tank 31. It's something you get. On the other hand, unit 2b on the stopped side
The liquid side branch pipe 23b is communicated with the tank 31 through a second bypass circuit to prevent refrigerant from unnecessarily accumulating inside (inside the coil 21b, piping 20b, etc.) and causing trouble in operation. Although a predetermined pressure is applied to this bypass circuit by the third bypass circuit 39, as the operation continues, the liquid in the unit 2b is gradually drained and accumulation of liquid refrigerant is prevented.

(v) When transitioning from two-room heating operation to one-room heating operation...For example, the load on the indoor unit 2a side decreases and the indoor thermostat (not shown) turns off the solenoid valve 18.
When the valves 24a and 24a are closed, the valve 41 is simultaneously opened for a predetermined period of time (several tens of seconds), and the refrigerant is allowed to flow from the gas side branch pipe 20b through the bypass circuit 42 into the unit 2a to be stopped.
In other words, if the normal valve 18a is closed, the pressure regulating valve 30 can prevent the increase in high pressure due to sudden load fluctuations.
However, in this case, by sending refrigerant to the unit 2a for a predetermined period of time during which the pressure regulating valve 30 can react, a sudden pressure increase is prevented and operation failure due to the activation of the pressure switch is prevented. be.

As is clear from the above description, according to the present invention, when transitioning from multi-room operation to small-room operation, high pressure increases due to sudden load changes can be avoided by allowing refrigerant to flow for a predetermined period of time to the indoor unit that should be stopped. Therefore, it is possible to prevent operation failure due to activation of the high pressure switch due to a delay in activation of the pressure regulating valve.
Furthermore, since the amount of refrigerant in the system can be adjusted to match the operating conditions, stable and efficient operation can be achieved.

[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, 16...Gas pipe, 20...Gas side branch pipe,
23... Liquid side branch pipe, 26... Sink pipe, 18a, 1
8b, 24a, 24b...Solenoid valve, 41...Solenoid valve, 42...Bypass circuit.

Claims (1)

[Claims] 1. When performing air conditioning and heating by connecting multiple indoor units to one outdoor unit with refrigerant piping, adjust the amount of refrigerant that should be bypassed between the liquid pipe through which high-pressure liquid passes and the low-pressure suction pipe during heating operation. A first bypass circuit having a refrigerant adjustment tank is provided via a pressure adjustment valve, and a first bypass circuit including a check valve and a capillary tube is provided between the liquid side branch pipe of each indoor unit and the refrigerant adjustment tank. In addition to providing a second bypass circuit, a third bypass circuit connected to a high pressure gas pipe is provided to apply a predetermined pressure to the second bypass circuit, and a liquid pipe and a gas pipe connecting the two units are provided. Each liquid side branch pipe and gas side branch pipe is provided with a solenoid valve that opens and closes in response to the operation of the indoor unit, and a bypass circuit is provided to connect the gas side branch pipes of each indoor unit via the solenoid valve. A heat pump type multi-room air-conditioning/heating device comprising: a heat pump type multi-room heating and cooling device; and the solenoid valve is configured to open for a predetermined period of time when transitioning from heating multi-room operation to small-room heating operation.