JPH04332352A - air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner that prevents overloading of a compressor during heating operation by stopping an outdoor fan.

0002

2. Description of the Related Art Hitherto, as this type of air conditioner, one shown in FIG. 3, for example, has been known. This air conditioner sequentially connects a compressor 11, a four-way switching valve 12, an indoor heat exchanger 13, a capillary tube 14 as a pressure reducing device, and an outdoor heat exchanger 15 through pipes 16a to 16f.
The outdoor heat exchanger 15 is equipped with an outdoor temperature sensor 17 and an outdoor fan 18 that detect the temperature of intake air, while the indoor heat exchanger 13 is equipped with an indoor temperature sensor 19 and an indoor fan 20 that detect the temperature. In addition, a pressure switch 21 is provided in the pipe line 16b between the four-way switching valve 12 and the indoor heat exchanger 13, and is turned off when the pressure of the refrigerant exceeds a certain value. , outdoor fan 18
A control section 22 is provided to stop the operation.

[0003] Now, when the outside air temperature rises during heating operation when the four-way switching valve 12 is switched to the path shown by the solid line in FIG. The temperature and pressure of the refrigerant gas increases, and the compressor 11 is overloaded, and the pipes 16a and 16b
The pressure of the refrigerant gas discharged also increases. When the pressure of this refrigerant gas exceeds a certain value, the pressure switch 2
1 is turned off, and upon receiving the off signal, the control section 22 stops the outdoor fan 18. Then, the amount of heat absorbed by the refrigerant from the outside air in the outdoor heat exchanger 15 decreases, and the compressor 11
The pressure of the refrigerant gas sucked into the compressor 11 decreases.
overload is prevented. Further, the control unit 22 determines that the pressure switch 21 has failed and operates as follows. That is, immediately after the compressor 11 is started, the pressure switch 21 is normally turned on because the pressure in the conduit 16b has not increased significantly, but it is turned off if there is a failure. Therefore, when the control unit 22 receives an off signal from the pressure switch 21 immediately after startup, it determines that there is a failure and the outdoor fan 18
completely stop.

0004

[Problems to be Solved by the Invention] However, in the conventional air conditioner described above, when the control section 22 determines that the pressure switch 21 is malfunctioning, the outdoor fan 18 is completely stopped. outdoor fan 18
The disadvantage is that the system does not work and heating operation cannot be performed after that point. In other words, if the pressure switch 21 malfunctions, there is no alternative means to detect overload on the compressor 11, so it is impossible to resolve the overload by starting or stopping the outdoor fan 18, and the outdoor fan 18 has to be completely stopped. You don't get it.

[0005] Therefore, an object of the present invention is to devise a simple overload detection means in place of a pressure switch.
To provide an air conditioner capable of continuing heating operation while preventing overload of a compressor even if a pressure switch breaks down.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the air conditioner of the present invention includes a compressor 11, a four-way switching valve 12, an indoor heat exchanger 13, a pressure reducing device, as illustrated in FIG. 14 and the outdoor heat exchanger 15 are sequentially connected to the pipes 16a to 16.
f, and includes an outdoor fan 18, an outdoor temperature sensor 17 that detects the intake air temperature of the outdoor heat exchanger 15, an indoor fan 20, and an indoor temperature sensor 19 that detects the temperature of the indoor heat exchanger 13. , detects whether the pressure of the refrigerant in the pipe line 16b between the four-way switching valve 12 and the indoor heat exchanger 13 is above a certain value, and when the pressure is above the certain value, the outdoor fan 1 is turned on.
Immediately after starting the compressor, the pressure switch 21 outputs a stop signal to stop the compressor.
a first determining means for determining whether the temperature Ta indicated by the detection signal of the outdoor temperature sensor 17 is equal to or higher than a certain temperature T1 when a stop signal is output from the outdoor temperature sensor 17; The present invention is characterized in that the controller 1 is provided with a first control means for stopping the outdoor fan 18 for a predetermined period of time or driving it at a low speed. Further, the control unit 1 is configured to determine whether or not the temperature Ti indicated by the detection signal of the indoor temperature sensor 19 is less than the constant temperature T2 when the first control means stops the outdoor fan 18 or drives the outdoor fan 18 at a low speed. 2 discriminating means, and a second controlling means for driving the outdoor fan 18 at high speed when the second discriminating means makes a positive determination.

[0007]

[Operation] If the pressure switch 21 provided in the pipe line 16b between the four-way switching valve 12 and the indoor heat exchanger 13 is out of order, it will not respond to the pressure in the pipe line 16b and the compressor Outputs a stop signal immediately after startup. The first determining means of the control unit 1 is
When the stop signal is received from the pressure switch 21 immediately after the compressor is started, it is determined that there is a failure, and the temperature Ta of the intake air indicated by the detection signal of the outdoor temperature sensor 17 is set to a constant temperature T1 that causes an overload on the compressor 11. Determine whether or not the value is greater than or equal to the value. If the first determining means determines that the temperature is equal to or higher than the constant temperature T1, the first controlling means of the control unit 1 stops the outdoor fan 18 for a predetermined period of time or drives it at a low speed. As a result, the amount of heat absorbed by the refrigerant from the outside air in the outdoor heat exchanger 15 is reduced, the pressure of the suction refrigerant is reduced to a constant value, and overload of the compressor 11 is prevented.

Further, the control section 1 operates as follows when a second determination means and a second control means are added. The first determining means of the control unit 1 is that the pressure switch 2 is detected immediately after the compressor is started.
When a stop signal is received from 1, as described above, it is determined that there is a failure, and it is determined whether the temperature Ta of the intake air detected by the outdoor temperature sensor 17 is equal to or higher than the constant temperature T1, and if it is determined to be positive, the first control means , the outdoor fan 18 is stopped for a predetermined period of time or is driven at a low speed. This prevents the compressor 11 from being overloaded, as described above. At this time, the second determining means of the control unit 1 determines that the temperature Ti of the indoor heat exchanger 13 measured by the indoor temperature sensor 19 is a constant temperature T2 with a surplus of heating the room further.
Determine whether it is less than or not. If the second determining means determines that the temperature is lower than the constant temperature T2, the second controlling means of the control section 1 drives the outdoor fan 18 at high speed. As a result, the amount of heat absorbed by the refrigerant from the outside air increases, the compressor 11 operates under a higher load, and the room is further heated.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to illustrated embodiments. FIG. 1 shows an example of an air conditioner according to the present invention, and this air conditioner differs only in that a new control section 1 is provided in place of the refrigerant circuit control section 22 described in FIG. . Therefore, the same members as in FIG. 3 are given the same numbers and their explanations will be omitted. The control unit 1 plays the roles of first determining means, first controlling means, second determining means, and second controlling means during heating operation. That is, the control unit 1 uses the pressure switch 2 as the first determining means immediately after starting the compressor 11.
1, when an off signal representing a high pressure higher than a certain value is input, it is determined that the pressure switch 21 is malfunctioning (see S1 in FIG. 2), and an error is displayed on the remote controller (not shown) (S2 in the same figure). reference). Next, it is determined whether the temperature Ta indicated by the detection signal of the outdoor temperature sensor 17 is equal to or higher than a certain temperature T1 that causes an overload on the compressor 11 (see S3), and when it is determined that the temperature Ta is equal to or higher than the constant temperature T1, the 1 control means outputs a control signal to the outdoor fan 18, stops it for a predetermined time (t0 minutes) (see S4), and then drives it at a low speed (see S5). Further, when the outdoor fan 18 is driven at a low speed, the second determination means determines whether the temperature Ti represented by the detection signal of the indoor temperature sensor 19 is a constant temperature T2 that has a surplus of heating the room further.
(see S6), and when it is determined that the temperature is below the constant temperature T2, the second control means outputs a control signal to the outdoor fan 18 to drive it at high speed (see S7). ). Note that the constant temperature T2 is considerably higher than the constant temperature T1. On the other hand, if the off signal is not input from the pressure switch 21 immediately after startup, it is determined that the pressure switch 21 is normal, and as already described in FIG.
While the ON signal is output, the outdoor fan 18 is driven at high speed (see S8 and S7 in FIG. 2), and when the OFF signal is output, the outdoor fan 18 is stopped (see S9 in the same figure).

The control section 1 having the above configuration operates as follows according to the flowchart of FIG. When the control unit 1 receives an off signal from the pressure switch 21 immediately after starting the compressor 11 during heating operation, the control unit 1 turns off the pressure switch 2 in step S1.
1 is determined to be malfunctioning, and after displaying an error message on the remote control in step S2, it is determined in step S3 whether or not the temperature Ta of the intake air measured by the outdoor temperature sensor 17 is equal to or higher than a certain temperature T1. If yes, that is, if it is determined that the compressor 11 is overloaded, the process proceeds to step S4, where the outdoor fan 18
After stopping for a certain period of time (t0 minutes), this is performed in step S.
5 to drive at low speed. Then, the amount of heat absorbed by the refrigerant from the outside air in the outdoor heat exchanger 15 is reduced, the pressure of the suction refrigerant is reduced to a certain value, and overload of the compressor 11 is prevented.
By driving the outdoor fan 18 at low speed, the amount of heat absorbed by the refrigerant from the outside air increases again. Next, in step S6, the control unit 1 uses the indoor temperature sensor 19 to determine whether the temperature Ti of the indoor heat exchanger 13 is less than a constant temperature T2. and,
Yes, in other words, if it is determined that there is surplus power to further heat the room,
Proceeding to step S7, the outdoor fan 18 is driven at high speed. As a result, the amount of heat absorbed by the refrigerant from the outside air increases even more.
The compressor 11 operates at a higher load to further heat the room. Note that if the determination in step S6 is negative, there is no remaining heating power, so the outdoor fan 18 continues to be driven at low speed. On the other hand, if the determination in step S3 is negative, the temperature Ta of the intake air is low and there is no risk of overload, so step S7
Then, the outdoor fan 18 is driven at high speed.

As described above, in the present invention, the pressure switch 2
1 fails, the outdoor temperature sensor 17 instead detects the overload of the compressor, and the control section 1 starts and stops the outdoor fan 18 based on the detection result.
Even if the pressure switch 21 fails, the heating operation can be continued while preventing the compressor 11 from being overloaded, which is very convenient. Further, in the above embodiment, when the control unit 1 drives the outdoor fan 18 at low speed when the pressure switch 21 fails, the control unit 1 further determines whether there is room for heating based on the detection signal of the indoor temperature sensor 19. If there is surplus power, the outdoor fan 18 is driven at high speed, which has the advantage that the full capacity of the compressor 11 can be used for heating.

0012

[Effects of the Invention] As is clear from the above explanation, the air conditioner of the present invention includes a compressor, a four-way switching valve, an indoor heat exchanger,
The pressure reducing device and the outdoor heat exchanger are connected in sequence through a pipe line, and the pipe line between the four-way switching valve and the indoor heat exchanger is equipped with an outdoor fan, an outdoor temperature sensor, an indoor fan, and an indoor temperature sensor.
In devices equipped with a pressure switch that outputs a stop signal to the outdoor fan when the refrigerant pressure is above a certain value, when the stop signal is output from the pressure switch immediately after the compressor starts, the outdoor temperature sensor detects the a first determining means for determining whether the temperature of the intake air represented by the signal is equal to or higher than a certain temperature; and a first determining means for stopping the outdoor fan for a predetermined period of time or driving the outdoor fan at a low speed when the first determining means determines in the affirmative. Since a control section having a control means is provided, even if the pressure switch breaks down, heating operation can be continued while preventing overload of the compressor with a simple configuration. Further, when the first control means stops or drives the outdoor fan at low speed, the second determination means determines whether the temperature detected by the indoor temperature sensor is less than a certain temperature, and when it is determined in the affirmative, the second control means By driving the outdoor fan at high speed, the full capacity of the compressor can be used for indoor heating.

[Brief explanation of drawings]

FIG. 1 is a refrigerant circuit diagram showing an example of an air conditioner according to the present invention.

FIG. 2 is a flowchart showing the flow of control by the control unit in FIG. 1;

FIG. 3 is a refrigerant circuit diagram of a conventional air conditioner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Control part, 11...Compressor, 12...Four-way switching valve, 13...
Indoor heat exchanger, 14... Capillary tube, 15... Outdoor heat exchanger, 16a to 16f... Pipe line, 17... Outdoor temperature sensor, 18... Outdoor fan, 19... Indoor temperature sensor, 20...
Indoor fan, 21...pressure switch.

Claims (2)

[Claims] [Claim 1] Compressor (11), four-way switching valve (12)
, the indoor heat exchanger (13), the pressure reducer (14), and the outdoor heat exchanger (15) are connected in sequence through pipes (16a to 16f), and the outdoor fan (18) and the outdoor heat exchanger (15) are The four-way switching valve (12) is equipped with an outdoor temperature sensor (17) that detects the intake air temperature, an indoor fan (20), and an indoor temperature sensor (19) that detects the temperature of the indoor heat exchanger (13). ) and the indoor heat exchanger (13) (16b)
In an air conditioner equipped with a pressure switch (21) that detects whether the pressure of the refrigerant is above a certain value and outputs a stop signal to stop the outdoor fan (18) when the pressure of the refrigerant is above the certain value. , the pressure switch (21) immediately after the compressor starts.
When a stop signal is output from the outdoor temperature sensor (
17) The temperature (Ta) represented by the detection signal is a constant temperature (T
1) A first determining means for determining whether or not the above is true; and a first controlling means for stopping the outdoor fan (18) for a predetermined time (t0 minutes) or driving it at a low speed when the first determining means determines that the above is true. An air conditioner comprising: a control section (1) comprising: 2. The control unit (1) is configured to control the temperature (Ti) represented by the detection signal of the indoor temperature sensor (19) when the first control means stops or drives the outdoor fan (18) at a low speed. a second determining means for determining whether the temperature is lower than a certain temperature (T2); and when the second determining means determines that the temperature is lower than a certain temperature (T2);
The air conditioner according to claim 1, further comprising second control means for driving said outdoor fan (18) at high speed.