JPS5838361Y2 - air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an air conditioner that includes a compressor and an outdoor fan, and is configured to switch the fan to high or low speed according to the outside temperature using an outdoor temperature controller.

Generally, in this type of air conditioner, when the outside air temperature rises during cooling, the high pressure of the refrigerant discharged from the compressor also rises, and the refrigerant temperature also rises, so the outdoor fan attached to the outdoor coil that exchanges heat with the outdoor air is set to high speed. The amount of heat exchange is increased by switching to operation, but as the high pressure of the refrigerant increases, the amount of heat released by the outdoor coil (Kcal/kg)
Therefore, the capacity of the outdoor fan when operating at high speed needs to increase by more than the capacity increase commensurate with the temperature difference between the refrigerant temperature and the outside air temperature. It was necessary to increase the speed ratio during operation, which resulted in noise problems during high-speed operation.

On the other hand, as the outside air temperature rises, the temperature of the motor coil of the compressor also rises, and it is necessary to prevent the motor coil from overheating.

In other words, the compressor motor coil temperature is determined by the compressor's high-pressure side pressure H, P and low-pressure side (pressure, P) as shown in Figure 3.
The high pressure side pressure H, P
increases with the outside temperature, whereas the low pressure side pressure,
Since there is almost no variation in P, the motor coil temperature is determined mostly by the high-pressure side pressures H and P, that is, it increases almost in proportion to the outside temperature, as shown by the dotted line a in FIG.

Therefore, conventionally, in order to prevent the motor coil from overheating,
Liquid is injected into the compressor.

However, this liquid injection is performed when the motor coil temperature reaches a predetermined temperature, and is performed completely independently of the above-mentioned switching of the outdoor fan.

For this reason, even when the outside air temperature becomes low and the high pressure of the refrigerant decreases and the amount of heat dissipated in the outdoor coil becomes small, liquid injection may occur, resulting in a decrease in cooling capacity and compressed wet gas. There was a problem with the air being inhaled into the aircraft.

Therefore, the present invention was devised in view of the above problems, and when the outside air temperature rises and the outdoor fan is switched to high-speed operation, the solenoid valve of the liquid injection circuit is opened to perform liquid injection. The liquid injection suppresses the increase in the heat radiation amount Kcal/kg in the outdoor coil due to the increase in the high pressures H and P of the refrigerant as the outside air temperature rises, and increases the capacity of the outdoor fan during high-speed operation. This eliminates the problem of noise by making it smaller, and at the same time lowers the compressor motor coil temperature to prevent overheating. Furthermore, when the outside temperature becomes low, the liquid injection is stopped and the liquid injection is continued. This also solves the problems of reduced cooling capacity and moisture compression due to continued use.

More specifically, a liquid injection circuit branched from a high-pressure liquid pipe is provided in the suction pipe of the compressor, and
A solenoid valve is connected to the liquid injection circuit, and the solenoid valve is opened in conjunction with the outdoor fan when the outdoor fan is operated at high speed by the outdoor temperature regulator.

Next, embodiments of the present invention shown in the drawings will be described.

First, FIG. 1 shows a refrigerant circuit of a generally known air conditioner, in which 1 is a compressor, and a compression element 2,
The compression element 2 is composed of a motor 4 equipped with a motor coil 3 for operating the compression element 2.

A condenser 6 is provided on the refrigerant discharge side of the compressor 1 via a high-pressure gas pipe 5, and a fan 7 is provided in the condenser 6. The compressor 6 and the fan 7 are housed in the same space and indoors. It is installed on the outside.

A liquid receiver 8 and an expansion valve 9 are connected to the refrigerant outlet side of the condenser 6 via a high-pressure liquid pipe 11, and a liquid receiver 8 and an expansion valve 9 are connected to the outlet side of the expansion valve 9 via a low-pressure liquid pipe 12. The evaporator 10 provided inside is connected, and the evaporator 10 is connected to the compressor 1.
The refrigerant discharged from the compressor 1 is condensed in the condenser 6, sent to the evaporator 10, where it is evaporated, and then circulated to the compressor 1. Configure.

Therefore, in the refrigerant circuit as described above, the present invention provides a high-pressure liquid pipe 12 between the liquid receiver 8 and the expansion valve 9, and a compressor 1.
A liquid injection circuit 20 is formed between the liquid injection circuit 20 and the suction pipe 13, and a solenoid valve 21 is interposed in the circuit 20, and this solenoid valve 21 is controlled by a control circuit as shown in FIG.

That is, a double-pole double-throw temperature regulator 17 having two switching pieces 15 and 16 is incorporated into the circuit of the condenser motor 14 that drives the outdoor fan 7 described above, and one switching piece 15 of the regulator 17 is used to control the above-mentioned temperature. The condenser motor 14 is designed to be switched from high speed to low speed, and a coil S of a energized closed solenoid valve 21 is inserted in the circuit in parallel with the condenser motor 14, and this solenoid valve coil Sv is connected to the temperature controller 17. The opening/closing operation is performed by the other switching piece 16.

The temperature regulator 17 is installed near the condenser 6 as shown in FIG.
Further, the other switching piece 16 is switched to turn on the solenoid valve coil Sv, and the motor 14, that is, the fan 7 is operated at high speed, and the solenoid valve coil SV is energized to turn on the solenoid valve 2.
On the other hand, if the outside temperature is below the set temperature, the switching piece 15 is switched to the low speed side of the motor 14 to operate the motor 14, that is, the fan 7 at low speed, and the switching valve 21 is turned off. Therefore, the solenoid valve 21 is closed.

Incidentally, it is possible to use an energized closed type as the solenoid valve 21, and in this case, a solenoid valve coil is installed at a position where the switching piece 16 is switched when the temperature controller 17 becomes lower than the set temperature. A contact point of S■ is provided.

Furthermore, instead of the temperature regulator 17, a single-pole, single-throw type may be used.

The above air conditioner operates as follows.

First, the refrigerant discharged from the compressor 1 reaches the condenser 6 where it is condensed, and then flows from the liquid receiver 8 through the expansion valve 9 to the evaporator 10, where the refrigerant is evaporated and vaporized to the compressor 1.
The refrigerant is circulated through this route.

At this time, if the outside temperature is below the set temperature of the temperature regulator 17, one switching piece 15 in the regulator 17 is switched to the low speed side of the condenser motor 14, and the motor 14, that is, the fan 7 is operated at a low speed. , and the other switching piece 16
is switched to turn off the solenoid valve coil SV, thereby closing the solenoid valve 21 and closing the aforementioned liquid injection circuit 20.

Further, when the outside temperature exceeds the set temperature, the temperature regulator 1
One switching piece 15 of 7 is switched to the high speed side of the condenser motor 14 to rotate the motor 14, that is, the fan 7 at high speed, and the other switching piece 16 is switched to turn on the solenoid valve coil S, so that the electromagnetic The valve 21 is opened to open the liquid injection circuit 20.

Then, the liquefied refrigerant, that is, Liquirad, passing through the high-pressure liquid pipe 12,
It is injected into the compressor 1 from the circuit 20 through the suction pipe 13, and lowers the temperature of the coil 3 of the motor 4 in the compressor 1.

That is, for example, if the set temperature of the temperature regulator 17 is set to 30°C, the liquid injection described above will be performed when the outside temperature reaches 30°C, and the motor coil 3 of the compressor 1 shown by the straight line a in FIG. As shown in the straight line shown by the dashed line in FIG. 3, the temperature has a gentle gradient with the 30° C. as a reference.

As explained above, the present invention switches the outdoor fan to high-speed operation when the outside temperature rises, opens the liquid injection circuit at the same time, and injects liquid from the high-pressure liquid pipe into the suction pipe of the compressor. As a result, the temperature of the motor coil in the compressor can be lowered, and an increase in the heat radiation amount Kcal/kg in the outdoor coil acting as a condenser can be suppressed, and the capacity of the outdoor fan during high-speed operation can be reduced. That way, you can lower the rotation speed.

Therefore, it has been possible to minimize the noise caused by the fan during high-speed operation.

In addition, this invention is configured to open and close the solenoid valve, that is, the liquid injection circuit, in conjunction with the temperature controller, so if the outside temperature becomes low and the required amount of heat dissipation from the outdoor coil becomes small, liquid injection will be stopped. Therefore, the cooling capacity of the air conditioner is not unnecessarily reduced, and moisture compression does not occur.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a refrigerant circuit of an air conditioner according to the present invention;
FIG. 2 is a diagram showing the control circuit of the liquid injection circuit, and FIG. 3 is a graph showing the relationship between the high and low pressures of the refrigerant and the compressor motor coil temperature with respect to the outside air temperature. 1...Compressor, 5...High pressure liquid pipe, 7.
...Fan, 11...Suction pipe, 12...
...Liquid injection circuit, 13...
...Solenoid valve, 17...Temperature controller.

Claims (1)

[Scope of utility model registration request] An air conditioner comprising a compressor and an outdoor fan, and in which the fan can be operated at high or low speed by an outdoor temperature controller, wherein a liquid injection circuit is branched from a high-pressure liquid pipe to a suction pipe of the compressor. In addition to providing
Connect a solenoid valve to the liquid injection circuit,
An air conditioner characterized in that the solenoid valve is opened in conjunction with the outdoor fan when the outdoor fan is operated at high speed by the outdoor temperature regulator.