JPS5952345B2 - air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a multi-type air conditioner comprising an outdoor unit and a plurality of indoor units.

[Technical background of the invention]

Generally, this type of air conditioner includes one equipped with a heat pump type refrigeration cycle as shown in FIG.

In FIG. 1, A is an outdoor unit and B is an outdoor unit. C is an indoor unit.

Thus, the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the capillary tube 4.5, the pressure reducing device such as the expansion valve 6, the capillary tubes 11 and 21 for flow control, the liquid line opening/closing valve 12 and 22, and the indoor heat exchanger. The heat pump type refrigeration cycle is constructed by sequentially communicating the gas line opening/closing valve 14, 24, etc. with the heat pump refrigeration cycle.

That is, the indoor heat exchangers 13 and 23 are configured in parallel.

During cooling operation, the refrigerant flows in the direction of the solid arrow shown in the figure, and during heating operation, the four-way valve 2 is switched, so that the refrigerant flows in the direction of the broken line arrow.

A liquid injection cycle 30 is provided between the refrigerant outlet pipe of the expansion valve 6 and the compression chamber of the compressor 1 via a capillary tube 31.

This liquid injection cycle 30 injects refrigerant into the compression chamber of the compressor 1.

Further, one end of a liquid return cycle 40 is connected to the refrigerant pipe between the liquid line on-off valve 12 and the indoor heat exchanger 13, and the other end of this liquid return cycle is connected to the capillary tube 4.5 through a capillary tube 41. and the expansion valve 6 .

Furthermore, one end of the liquid return cycle 50 is connected to the refrigerant pipe between the liquid line on-off valve 22 and the indoor heat exchanger 23,
The other end of this liquid return cycle 50 is a capillary tube 5
1 to the refrigerant pipe between the capillary tubes 4 and 5 and the expansion valve 6.

These liquid return cycles 40 and 50 have the following functions.

That is, when indoor units) B and C are in heating operation, for example, when the operation of indoor unit C is stopped, the gas line on-off valve 24 and the liquid line on-off valve 22 are closed, and the indoor heat exchange is started. The discharge gas refrigerant is prohibited from flowing into the vessel 23.

At this time, the discharged gas refrigerant that has already flowed into the indoor heat exchanger 23 accumulates there, and since the collected discharged gas refrigerant has a high temperature, it exchanges heat with the outside and is gradually cooled and becomes liquid.

However, if the liquid refrigerant accumulates in the indoor heat exchanger 23,
When the operation of the indoor unit C is restarted, the gas balance of the refrigeration cycle will be disrupted, and furthermore, there is a risk that the liquid refrigerant will return to the compressor 1 and cause liquid compression, causing damage to the compressor 1.

Therefore, the liquid refrigerant generated in the indoor heat exchanger 23 is returned to the liquid line side by the liquid return cycle 50 to prevent the above-mentioned problems from occurring.

[Problems with background technology]

By the way, in such an air conditioner, when the operation of the indoor unit C is stopped, the refrigerant pressure on the gas line on-off valve 24 side is higher than the refrigerant pressure on the liquid line on-off valve 22 side.
If the operation of the indoor unit C is restarted in this state, the discharged gas refrigerant will suddenly flow into the indoor heat exchanger 23, causing a loud refrigerant noise and causing discomfort or distrust to the people in the room, which could be a problem. was there.

[Purpose of the invention]

This invention was made in view of the above circumstances,
The purpose is to provide an excellent air conditioner that can reduce refrigerant noise when the idle unit starts operating, thereby improving reliability.

[Summary of the Invention] The present invention provides the following methods: when starting the operation of at least one of the indoor heat exchangers, all on-off valves are temporarily closed to prohibit the flow of refrigerant into each indoor heat exchanger; , the four-way valve is reversed, thereby measuring the gas balance in the refrigeration cycle, and then the four-way valve is restored and the on-off valves corresponding to the indoor heat exchangers that need to be operated are opened.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In this case, it is assumed that a heat pump type refrigeration cycle similar to that shown in FIG. 1 is provided.

In Figure 2, between terminals 61 and 62 there is a compressor operation signal (AC power supply voltage) ■1, between terminals 61 and 63 there is an indoor unit) B operation signal (AC power supply voltage) V2, and terminals 61 and 64.
Between the indoor unit C operation signal (AC power supply voltage)■3,
Heating operation signal (AC power supply voltage) V is connected between terminals 61 and 65.
4 is applied.

Therefore, the excitation coil 71C of the indoor unit B operation detection relay 71 is connected between the terminals 61 and 63.
．． 64, an excitation coil 72C of the indoor unit C operation detection relay 72 is connected.

An excitation coil 73C of the indoor unit I-B, C operation detection relay 73 is connected between the terminals 61 and 62 through the contact 71a of the relay 71 and the contact 72a of the relay 72 in series.

Further, a timer motor 74M of a timer 74 is connected between the terminals 61 and 62 with contacts 71a and 72a connected in series.

Furthermore, a contact 73 of a relay 73 is connected between terminals 61 and 63.
A parallel body of the excitation coil 14C of the gas line on-off valve 14 and the excitation coil 12C of the liquid line on-off valve 12 is connected via the normally closed side of a.

A parallel body of the excitation coil 24C of the gas line on-off valve 24 and the excitation coil 22C of the liquid line on-off valve 22 is connected between the terminals 61 and 64 via the normally closed side of the contact 73a.

The excitation coil 2C of the four-way valve 2 is connected between the terminals 61 and 65 via the normally closed side of the contact 73a.

A series circuit consisting of the normally open side of the contact 73a and the normally open side of the time limit contact 74a of the timer 74 is connected in parallel to the normally closed side of the contact 73a.

The timer 74 switches the time limit contact 74a to the normally open side after a certain period of time after being energized by the operation of the timer motor 74M, and maintains this state while being energized.

Next, the operation in the above configuration will be explained.

Now, when heating operation is set for both indoor units l-B and C, compressor 1 starts operating, and compressor operation signal v1, indoor unit B operation signal v2, indoor unit C operation signal ■3, and heating Operation signal V4 is generated.

Then, relays 71 and 72 are activated and contacts 71a and 72 are activated.
a closes, which activates the relay 73 and closes the contact 73.
When the normally open side of a is closed, the operation of the timer motor 74M of the timer motor 74 is started.

Therefore, when the timer motor 74 measures a certain period of time,
The normally open side of the time limit contact 74a is closed, and the on-off valves 14,1
2.24 and 22 open respectively, and the four-way valve 2
is switched.

In this way, a heating cycle is formed through the indoor heat exchangers 13 and 23, and heating operation is performed in the indoor units) B and C.

By the way, when the heating operation is terminated in the indoor unit C, or the temperature of the room where the indoor unit C is installed exceeds the set value, the indoor unit C operation signal V3 is activated.
is blocked.

Then, the on-off valves 24 and 22 close and the indoor heat exchanger 23
The discharge gas refrigerant is prohibited from flowing into the unit B, and the heating operation in the indoor unit B is terminated (interrupted).

At this time, the operation of the relay 72 is stopped by the interruption of the indoor unit C operation signal v3, and the operation of the relay 73 and the timer 74 are respectively stopped by the opening of the contact 72a.

In other words, the contacts 73a and 74a each return to the normally closed state.

At this time, the opening operation of the on-off valves 14 and 22 and the four-way valve 2
The operation continues through the energizing path formed by the normally closed side of contact 73a.

In addition, at this time, the discharged gas refrigerant is accumulated in the indoor heat exchanger 23, and it gradually becomes liquefied by heat exchange with the outside, but the liquid refrigerant is passed through the liquid return cycle 5.
0 returns to the liquid line.

After that, when the heating operation is started in the indoor unit C or the temperature of the room where the indoor unit C is installed falls below the set value, the indoor unit C operation signal V3 is activated.
occurs.

Then, first, the relay 72 is activated and its contact 72a is closed, whereby the relay 73 and the timer 74 start to operate.

That is, the normally open side of the contact 73a closes and the time limit contact 74a returns.

In this way, the energizing path to the on-off valves 14, 12, 24, 22 is cut off, all of the on-off valves are closed, and the indoor heat exchanger 1
3. Refrigerant flow into 23 is prohibited.

Further, the current supply path to the four-way valve 2 is also cut off, and the four-way valve 2 is reversed (stops operating), thereby ensuring gas balance in the refrigeration cycle.

In other words, the refrigerant pressure on the liquid line on/off valves 12, 22 side is not significantly different from the refrigerant pressure on the gas line on/off valves 14, 24 side.

When the timer 74 measures a certain period of time, the normally open side of the time limit contact 74a closes, and the on-off valve 14. 12. 24, 22 and the four-way valve 2 are formed.

In this way, all of the on-off valves 14, 12, 24, and 22 are opened, and the four-way valve 2 returns to its original state, forming a heating cycle through the indoor heat exchangers 13 and 23.

That is, the heating operation of the indoor unit )H continues, and the heating operation of the indoor unit C is resumed.

At this time, when the on-off valves 14, 12, 24, 22 are opened, the four-way valve 2 is once reversed to ensure gas balance, so that the discharged gas refrigerant is transferred to the indoor heat exchanger 13.
．． The refrigerant flows slowly into the refrigerant 23 and does not flow in suddenly as in the conventional case, thereby reducing refrigerant noise.

In particular, since the gas balance is measured without stopping the operation of compressor 1, the heating start-up is quick and the 5EE
R (annual energy consumption efficiency) also improves.

In addition, there is a concern that the temperature of the air blown into the room may drop when heating operation resumes, but the indoor heat exchanger 13.23
There is no need to worry about this because the high-temperature refrigerant was held in the tank.

Furthermore, during gas balance, all on-off valves are closed and the flow of refrigerant is stopped, so there is a concern that the high pressure may rise abnormally, but the discharged gas refrigerant enters the outdoor heat exchanger 3 and there In order to condense and liquefy, and outdoor heat exchanger 3
Since the capacity is large, and considering that the gas balance time (measured by the timer 74) is about 1 to 2 seconds, there is no abnormal rise in high pressure.

However, depending on the situation, the risk of an abnormal rise in high pressure cannot be ignored, so it may be possible to improve safety by providing a high pressure release cycle as shown in FIG.

That is, in FIG. 3, a high pressure release cycle 80 is provided between the refrigerant inflow side piping of the expansion valve 6 and the refrigerant suction side piping of the compressor 1 via an on-off valve 81 and a capillary tube 82.

As shown in FIG. 4, the excitation coil 81C of the on-off valve 81 is connected between the terminals 61 and 62 via the normally open side of the relay contact 73a and the normally closed side of the time limit contact 74a in series, and the gas balance At the same time, the high pressure release cycle 80 is turned on.

According to such a configuration, it is possible to reliably prevent an abnormal rise in high pressure, and it is also possible to reduce refrigerant noise in the outdoor heat exchanger 3 that may occur when switching from normal operation to gas balance.

Incidentally, in the above embodiment, the description has been made regarding the start of operation of the indoor unit)C, but it goes without saying that the same effect can be obtained when the operation of the indoor unit)B is started.

Furthermore, if the compressor 1 has a variable capacity function, more significant effects can be obtained by controlling the compressor 1 at the start of operation with the capacity reduced to the minimum capacity.

Further, although control is performed using a combination of a relay and a timer, it is also possible to perform software control using a microcomputer, which eliminates the need for a timer and is advantageous in terms of cost.

Furthermore, although I mentioned the case where there are two indoor units,
The same method can be applied even when there are a larger number of indoor units.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reduce the refrigerant noise at the time of starting the operation of the idle unit, thereby providing an excellent air conditioner that can improve reliability.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional refrigeration cycle and an embodiment of the present invention, FIG. 2 is a block diagram of the main part of the control circuit in the same embodiment, and FIG. 3 is a block diagram of another embodiment of the present invention. FIG. 4 is a block diagram of a heat pump type refrigeration cycle in an embodiment, and FIG. 4 is a block diagram of a main part of a control circuit in another embodiment. A... Outdoor unit, B, C... Indoor unit, 1... Compressor, 2... Four-way valve, 12, 14° 22.24. ...Opening/closing valve, 1
3,23... Indoor heat exchanger, 71...
Indoor unit) B operation detection relay, 72... Indoor unit C operation detection relay, 73... Indoor unit 1-B-C operation detection relay, 74... Timer.

Claims (1)

[Claims] 1 A heat pump refrigeration cycle consisting of a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducing device, a parallel body of a plurality of indoor heat exchangers, etc. connected in sequence, and refrigerant piping to each of the indoor heat exchangers. and an on-off valve that controls the inflow of refrigerant into each indoor heat exchanger, and when starting the operation of at least one of the indoor heat exchangers, all of the on-off valves are temporarily closed, and Once the four-way valve is reversed,
An air conditioner characterized by comprising a control circuit that subsequently restores a four-way valve and opens an on-off valve corresponding to an indoor heat exchanger that needs to be operated.