JPS6331713B2 - - Google Patents

Description

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

In general, in this type of air-conditioning equipment, when a small number of units are operated during heating, the capacity of the indoor unit that serves as the condenser is relatively reduced, resulting in a surplus of refrigerant and a rise in high pressure, causing operation by activation of the high-pressure pressure switch. Sometimes it can lead to incapacitation. In other words, when operating a small number of units, surplus refrigerant is stored in a tank that communicates with the low pressure side, such as a refrigerant adjustment tank, or a portion of the high pressure gas is bypassed through the indoor unit, and these liquid bypasses or gas bypasses are installed within the system. This is controlled by a pressure regulating valve that operates according to the pressure of However, this pressure regulating valve has a slight delay in its operation due to its structure, and cannot sufficiently follow sudden fluctuations such as when changing from two-chamber operation to one-chamber operation, for example. Immediately after transitioning from multi-room operation to small-room operation,
During the period until stabilization (usually several tens of seconds, depending on the length of the piping), the high pressure rose rapidly, sometimes causing the high pressure switch to operate.

In order to solve this problem, the present invention is designed to bypass the pressure regulating valve for a predetermined period of time after transition from multi-chamber operation to small-chamber operation, 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 3, and pipe branching units 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 indicates a large number of capillary tubes arranged in parallel to evenly distribute refrigerant to the outdoor coil 5, and reference numeral 12 indicates a check joint conduit that communicates with a pipe section that is at high pressure during cooling operation and low pressure during heating operation. It is used for pressure checking, 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. Reference numeral 16 indicates a gas pipe connected to the service valve 14, and a branch point 17 leads to solenoid valves 18a, 18b and check valves 19a, 19, respectively.
The gas side branch pipes 20a, 20b are connected via parallel circuits b.
These branch pipes 20a and 20b connect to the indoor coils 21a and 21a of the indoor units 2a and 2b, respectively.
21b. A liquid side branch pipe 23 is connected from each coil 21a, 21b of the indoor units 2a, 2b via an indoor capillary tube 22a, 22b.
a, 23b, and connected to liquid side reversible flow type on-off solenoid valves 24a, 24b in the branch unit 3. From these solenoid valves 24a and 24b, there is a branch point 25.
The liquid pipes join together to form a liquid pipe 26 and are connected to the service valve 13. Reference numeral 27 is a bypass solenoid valve when operating a single cooling room, which connects a liquid pipe 26 which becomes high-pressure liquid during cooling and a gas pipe 1 which becomes low-pressure gas through a capillary tube 28.
It will be installed between 6 and 6. In other words, in this bypass circuit, the capillary tubes 22a and 22b, which are properly set when operating in two cooling rooms, become too constricted as a whole system when operating in one room due to their characteristics.
This is a liquid bypass circuit that prevents the discharge temperature of the compressor 4 from rising. 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 service valve 1 is connected to the liquid pipe 26, and the other end is connected to the pipe line 12, which becomes the low-pressure suction side.
5 to constitute a first bypass circuit. That is, by opening the valve 29, the pressure regulating valve 30 senses the pressure from the liquid pipe 26 and adjusts its opening while drawing the liquid refrigerant through the liquid pipe 26 and guiding it to the tank 31 for storage. 3
The amount of refrigerant in the tank 31 is adjusted by the gas side capillary tube 32 for removing gas in the tank 31, that is, the amount of liquid refrigerant stored is controlled. The refrigerant is gradually returned to the low pressure side via the valve 15. Furthermore, a solenoid valve 3 is connected in parallel with the pressure regulating valve 30.
5, and this solenoid valve 35 is used to switch the indoor units 2a, 2b from two-room operation to one-room operation (for example, when the indoor thermostat of one unit is turned off, the one-room side is switched off). For example, it is opened for several tens of seconds by a timer (not shown) only when the system is at rest. In other words, the pressure regulating valve 30 when transitioning from two-chamber operation to one-chamber operation
The refrigerant is introduced into the tank 31 for a predetermined period of time regardless of the timing.

The first bypass circuit includes a capillary tube 37 and a check valve 3, which drain liquid from the tank 31 during cooling operation, since the pressure in the pipe line 12 is high during cooling.
8 is provided between the bottom of the tank 31 and the gas pipe 16 which becomes the low pressure side during cooling.

Also, when operating a single heating room, the solenoid valve 18
One of the valves a, 18b, 24a, and 24b is closed, but since all valves are under high pressure, refrigerant leaks and unnecessarily accumulates in the indoor unit on the idle side, causing damage to the refrigeration cycle. This may interfere with the operation of the unit 2.
A second bypass circuit consisting of check valves 39a, 39b and capillary tubes 40a, 40b is provided between the liquid side branch pipes 23a, 23b of a, 2b and the upper part of the refrigerant adjustment tank 31. This second bypass is further provided with a third bypass circuit 41 that applies pressure from the gas pipe 16, which becomes high-pressure gas during heating, between the check valves 39a, 39b and the capillary tubes 40a, 40b. There is. This third bypass circuit 41 has a capillary tube 42 interposed between the check valve 39 and the capillary tube 40 to reduce the pressure to such an extent that excessive pressure is not applied between the check valve 39 and the capillary tube 40 and completely prevents liquid drainage. ing.

Next, the operation and effects of the above configuration will be explained.

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,
24b, 18a, and 18b are opened, respectively.

When operating one air conditioner...for example, indoor unit 2a
In the operation, the solenoid valves 24b and 18b are closed, and the bypass solenoid valve 27 is opened to prevent the discharge pressure from increasing. In addition, in the above-mentioned cooling operation, the pressure in the pipe line 12 becomes high, so the first,
The second bypass circuit is inactive.

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 gas pressure applied by the third bypass circuit 41. There is almost no reduction in performance.

When operating a heating room...for example, indoor unit 2a
In the operation, the solenoid valves 24b and 18b are closed, and the solenoid valve 29 of the first bypass circuit is opened. In other words, the indoor coil 21a acts as a condenser.
The pressure regulating valve 30 suppresses the increase in high pressure due to a relative decrease in the capacity of the chamber (compared to two-chamber operation).
The inflow of the refrigerant is sensed by the refrigerant and controlled by the refrigerant liquid stored in the tank 31. On the other hand, inside the indoor unit 2b on the stop side (coil 21
The liquid side branch pipe 23b is communicated with the tank 31 through a second bypass circuit so that refrigerant does not accumulate unnecessarily in the inside of the pipe 20b, etc.) and impede the operation of the refrigerant cycle. Although a predetermined pressure is applied to this bypass circuit by the third bypass circuit 41, as the operation continues, the liquid in the unit 2b is gradually drained and accumulation of liquid refrigerant is prevented.

At the time of transition from heating two-room operation to single-room heating operation...at this time, the solenoid valve 35 is opened for a predetermined period of time (several tens of seconds) immediately after the transition. Therefore, the reduction in load that cannot be followed by the pressure regulating valve 30 alone is controlled by the valve 3 from the liquid pipe 26.
To cope with this, the refrigerant is introduced into the tank 31 regardless of the zero value. This prevents the pressure switch from operating due to a temporary high pressure increase during transition.

In the above embodiment, the pressure regulating valve 30 is connected to the first valve between the high pressure liquid pipe 26 and the low pressure pipe 12 during heating.
Although an example is shown in which a bypass circuit is provided in a bypass circuit, the present invention is not limited to this, and a bypass path (not shown) formed to bypass between a high-pressure gas pipe 16 and a high-pressure liquid pipe 26 for adjusting the amount of refrigerant circulation in the system is shown. A similar effect can be expected even if this valve is provided in the second chamber and is bypassed for a predetermined period of time when transitioning from two-chamber operation to one-chamber operation to cope with load fluctuations during the transition.

As is clear from the above description, according to the present invention, the pressure regulating valve that adjusts the amount of refrigerant to be bypassed is configured to bypass the refrigerant for a predetermined time regardless of the valve when transitioning from multi-chamber operation to small-chamber operation. This makes it possible to prevent a rise in high pressure due to a delay in valve operation, and to prevent an operation failure caused by a pressure switch.

[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...Pressure regulating valve, 36...Bypass circuit.

Claims (1)

[Claims] 1. In systems that connect multiple indoor units to one outdoor unit for heating and cooling, a predetermined high pressure in the system during heating operation is detected and liquid refrigerant is inserted between the high-pressure liquid pipe and the low-pressure suction pipe. A pressure regulating valve is provided to bypass the pressure regulating valve, and a bypass circuit is provided in parallel with this pressure regulating valve to bypass the pressure regulating valve, and a valve is provided in this bypass circuit that is opened for a predetermined period of time in conjunction with the control to reduce the number of operating indoor units. A heat pump type multi-room air conditioning system.