JPS635652B2 - - 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 pressure and low pressure, respectively, so by providing a bypass between them, the transition from multi-room operation to small-room operation can be carried out smoothly. It can be done. 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 in changing the operating state cannot be used. Therefore, it was necessary to control the amount of refrigerant to be returned to the low pressure side while storing excess refrigerant in the tank using a pressure regulating valve. Therefore, the high pressure increases due to the delay in the operation of the pressure regulating valve in response to a change in the pressure in the system when the operation is changed, and this sometimes results 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 that is 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, in this bypass circuit, although the capillary tubes 22a and 22b are properly set when operating in two cooling rooms, when operating in a single room, the entire system becomes too constricted due to its characteristics, and the discharge temperature of the compressor 4 increases. This is a liquid bypass circuit that prevents 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. The first bypass circuit is connected to the liquid pipe 26 passing therethrough, and the other end is connected to the service valve 15 connected to the pipe line 12 on the low-pressure suction side. 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 gas stored in the tank 31 is adjusted by the gas side capillary tube 32 for removing gas from the tank 31, that is, the amount of liquid refrigerant stored is controlled.
The refrigerant is gradually returned to the low pressure side through the 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 provided 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, bypass circuits 41a and 41b are provided in the parallel circuits of the electromagnetic valve 18 and the check valve 19 interposed in the gas side branch pipes 20a and 20b, respectively. These bypass circuits 41a and 41b are connected to solenoid valves 42a and 42b that are opened by the unit side that should be stopped for a certain period of time (for example, several tens of seconds) only when the heating operation shifts from two-room operation to one-room operation, and solenoid valve 18a. , 18b to be smaller than the flow rate of refrigerant flowing through the capillary tubes 43a, 43b.
It is formed by a series circuit of. In other words, although the circuit is not shown, when the unit to be stopped is the indoor unit 2a, the solenoid valve 42a is connected via a timer to the reverse contact side of the relay to close the solenoid valve 18a, and the solenoid valve 18a is closed. When the solenoid valve 42a is closed, the solenoid valve 42a is opened for a predetermined period of time set by a timer.

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 the indoor unit 2a is operating, 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 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,
24b, 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 blocked by the low pressure applied by the third bypass circuit 39. There is almost no reduction in performance.

(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 a and 24a are closed, the valve 42a is simultaneously opened for a predetermined period of time (several tens of seconds), thereby allowing the refrigerant to flow from the gas pipe 16 through the valve 42a and the capillary tube 43a into the unit 2a to be stopped. . In other words, normally when the valve 18a is closed, the pressure regulating valve 30 cannot immediately follow the rise in high pressure due to sudden load fluctuations, but here, the refrigerant is supplied to the unit 2a for a predetermined period of time during which the pressure regulating valve 30 can react. By sending a smaller amount of water than normal, a sudden rise in pressure is prevented, and operation failure due to activation of the pressure switch is prevented.

As is clear from the above explanation, according to the present invention, when transitioning from multi-room operation to small-room operation, the high pressure rise due to sudden load changes is applied to the indoor unit to be stopped less than to the operating indoor unit. Since this is prevented by flowing the refrigerant for a predetermined period of time, the stabilization time of the system is shortened, and it is also possible to prevent operation failure due to activation of the high pressure switch due to delay in activation of the pressure regulating valve. In addition, surplus refrigerant that matches the operating conditions is stored in the refrigerant storage tank by the pressure regulating valve, so the amount of refrigerant in the system can be adjusted to match the operating conditions, allowing stable and efficient operation.

[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, 26...Liquid pipe, 18a,
18b, 24a, 24b...Solenoid valve, 20...Gas side branch pipe, 41...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. A second bypass circuit is provided, and a third bypass circuit is provided that is connected to a gas pipe through which high-pressure gas passes during heating operation in order to apply a predetermined pressure to the second bypass circuit, and both of the units are connected. A solenoid valve that opens and closes in response to the operation of the indoor unit is installed in the liquid side branch pipe and gas side branch pipe of each liquid pipe and gas pipe, and among these solenoid valves, a solenoid valve is installed in the gas side branch pipe. A bypass circuit is provided in each of the solenoid valves to allow a refrigerant flow rate lower than that passing through the solenoid valve to pass therethrough, and this bypass circuit includes a bypass circuit to the indoor unit on the stopping side only when transitioning from heating multi-room operation to small-room heating operation. A heat pump type multi-room air conditioning system equipped with a solenoid valve that opens the air for a predetermined period of time.