JPH10110996A - Method and apparatus for controlling air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge clogging of a vent passage of a condenser by detecting refrigerant discharging, condensing and atmospheric temperatures, and rotational speed of a blower, and comparing a difference of calculated discharging and condensing temperatures with discharging and condensing temperature difference allowable value of the refrigerant previously obtained for the atmospheric temperature and rotational speed of the blower in the clogging state of the passage. SOLUTION: When a rotational speed of an outdoor blower 4 is accelerated, a heat exchange amount is increased, and hence a temperature difference of refrigerant from its discharging and condensing temperatures is increased. In the case of a cooling operation, when the atmospheric temperature rises, heat exchange of an outdoor heat exchanger 13 is not sufficiently conducted, and hence a compressor 7 becomes an overload operating state. Thus, temperature of discharge pressure is raised, and a temperature difference from the discharging and condensing temperatures is increased. Accordingly, set values of the atmospheric temperatures of respective levels in the clogging state of a vent passage of a condenser and the temperature difference from the discharging and condensing temperatures responsive to rotational speed of an outdoor blower of the respective levels are previously provided, the set value is compared with a temperature difference obtained from the detected discharging and condensing temperatures, and hence clogging of the operating state is judged. When the clogging is judged, a clogging display lamp is lit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an air conditioner, and more particularly to a method for detecting clogging in a ventilation path of a heat exchanger constituting a condenser for condensing refrigerant, and a method for dealing with the clogging. Control method and apparatus suitable for the above.

[0002]

2. Description of the Related Art As a prior art, Japanese Patent Application Laid-Open No. 61-4423
No. 9 discloses that the temperature of air in a heat exchanger or after passing through a heat exchanger and the temperature of air before passing through a heat exchanger are detected and supplied to the heat exchanger when the temperature difference between the two is larger than a certain value. It is disclosed that it is determined that the filter for purifying air to be cleaned is clogged. Although the above publication describes clogging of a filter for air supplied to a heat exchanger, it does not mention a method of determining clogging of the heat exchanger itself.

[0003]

Generally, when an outdoor heat exchanger as a condenser for condensing refrigerant is clogged with dust during a cooling operation of an air conditioner, the discharge pressure of the refrigerant discharged from the compressor is reduced. Or, the discharge temperature) increases, and there is a problem that the protection device operates even under the overload operation condition.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for judging clogging of a ventilation path of an outdoor heat exchanger in an air conditioner, and stabilizing the clogging before the protection device is activated due to the clogging. It is an object of the present invention to provide a control method and a device capable of performing a controlled refrigeration cycle.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, an air conditioner control method according to the present invention is directed to an air conditioner comprising a refrigeration cycle comprising a compressor, a condenser, an expansion mechanism and an evaporator. Detecting the discharge temperature of the refrigerant discharged from the compressor, the condensation temperature of the refrigerant condensed in the condenser, the outside air temperature around the condenser, and the rotation speed of the blower that blows outside air to the condenser, When the temperature difference between the discharge temperature and the condensation temperature is calculated, and the calculated temperature difference exceeds the allowable value obtained in advance for the outside air temperature and the number of rotations of the blower in a state where the ventilation passage of the condenser is clogged. Further, it is characterized in that it is determined that the condenser is clogged, and a clogging indication is displayed.

[0006] When clogging is determined as described above, it is preferable to perform stable refrigeration cycle control by increasing the rotation speed of the blower or operating the expansion mechanism in the opening direction. . Alternatively, the blower may be provided with a reversible electric motor, and if it is determined that the blower is clogged, the blower may be controlled to rotate in the reverse direction to remove the cause of the clogging.

According to another aspect of the present invention, there is provided a control apparatus for an air conditioner, comprising a compressor, a condenser, an expansion mechanism, and an evaporator. A first temperature detector for detecting a surrounding outside air temperature, a second temperature detector for detecting a discharge temperature of the refrigerant discharged from the compressor, and a third temperature for detecting a condensation temperature of the refrigerant condensed in the condenser A detector, a rotation speed detector for detecting the rotation speed of a blower that blows outside air to the condenser,
A temperature difference between the discharge temperature detected by the temperature detector and the condensing temperature detected by the third temperature detector is calculated, and the calculated temperature difference is calculated based on the outside air temperature and the air blower in a state where the ventilation passage of the condenser is clogged. Is compared with the allowable value of the difference between the discharge temperature of the refrigerant and the condensing temperature, which is obtained in advance for the rotation speed, and when the calculated temperature difference exceeds the allowable value, the display of the clogging and the rotation of the blower are performed. And a computer for outputting a clogging signal to increase the number.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a control circuit diagram of an air conditioner for realizing the control method of the present invention, FIG. 2 is a refrigeration cycle system diagram of the air conditioner, and FIG. 3 shows an operation state of the air conditioner due to clogging of an outdoor heat exchanger. It is a figure showing change of the shown factor.

(Embodiment 1) As shown in FIG. 2, an air conditioner comprises a compressor 7 for discharging a high-temperature and high-pressure refrigerant, and an outdoor heat exchange as a condenser for cooling and condensing the high-temperature and high-pressure refrigerant. An indoor expansion valve 10 for evaporating the expanded refrigerant and exchanging heat with the indoor air to cool the indoor air, and an accumulator 16 Are formed in order to form a refrigeration cycle, and an outdoor blower 4 for promoting heat exchange of the outdoor unit 17 and an indoor blower 15 for promoting heat exchange of the indoor unit 18 are provided. Further, an outside air thermistor 1 for detecting the outside air temperature, a discharged refrigerant thermistor 2 for detecting the temperature of the refrigerant discharged from the compressor 7, and a condensed refrigerant thermistor 3 for detecting the condensation temperature of the refrigerant in the outdoor heat exchanger 13 , A pressure sensor 6 for detecting a discharge pressure of the compressor 7, an outdoor blower 4
The refrigeration cycle control is performed using the wind speed sensor 9 that detects the wind speed of the refrigeration cycle.

Next, the control operation of the present invention will be described with reference to FIGS. The microcomputer 11 that is provided on the control board 12 and controls the refrigeration cycle of the air conditioner includes an outside air thermistor 1, a discharged refrigerant thermistor 2, a condensed refrigerant thermistor 3, a pressure sensor 6, a wind speed sensor 9, and a compressor 7. The outdoor blower 4 and the indoor electronic expansion valve 10 are controlled based on the information of the current sensor 8 for detecting the operating current of the air conditioner. Further, the microcomputer 11 controls the rotation speed of the outdoor blower 4 via the thyristor 5. The microcomputer 11 sets a temperature difference between the refrigerant discharge temperature and the condensing temperature that is allowed according to each outside air temperature and each rotation speed of the outdoor blower 4. The set value of the temperature difference is obtained in advance by a clogging test or a simulation calculation.

Here, the clogging of the outdoor heat exchanger 13 will be described with reference to FIG. As shown in the figure, the outdoor heat exchangers 13 are arranged in parallel with a narrow gap, a plurality of pipes are arranged in multiple stages so as to penetrate a large number of thin fins 20, and these pipes are connected at ends. So as to form one continuous refrigerant coil 21,
It is configured. In the outdoor heat exchanger 13, the refrigerant flowing through the coil 21 is cooled and condensed and liquefied by air supplied from the outside. During the operation of the outdoor heat exchanger 4, air passes through the gap between the fins 20, and the dust and the like 22 contained in the air adhere to the fins 20 and the pipe (21) and gradually accumulate. Fin 2
The gap of 0 is clogged.

As shown in FIG. 3, when the outdoor heat exchanger 13 is clogged, heat exchange in the outdoor heat exchanger 13 cannot be sufficiently performed, and the discharge temperature rises as the discharge pressure increases. Further, the condensation temperature also rises with the rise of the discharge temperature. However, since the rise A1 in the discharge temperature is larger than the rise A2 in the condensing temperature, the temperature difference between the discharge temperature and the condensing temperature increases from B1 to B2. When the temperature difference B2 exceeds the set value of the microcomputer 11, the outdoor heat exchanger 13 is determined to be clogged, and the clogging indicator lamp 19 is turned on. At this time, by setting the set value of the temperature difference between the discharge temperature and the condensation temperature (hereinafter referred to as the discharge / condensation temperature difference) according to the outside air temperature of each level and the rotation speed of each level of the outdoor blower 4, respectively. Clogging can be determined in an operation state at a proper outside air temperature and the rotation speed of the outdoor blower.

The setting of the set value for the discharge / condensation temperature difference according to the outside air temperature and the rotation speed of the outdoor blower 4 will be described with reference to FIG. The rotation speed of the outdoor blower 4 increases in the order of light wind → strong wind → rapid wind. When the rotational speed of the outdoor blower 4 increases, the amount of heat exchange in the outdoor heat exchanger 13 increases, and the discharge / condensation temperature difference also increases. In other words, by changing the set value of the discharge / condensation temperature difference depending on the rotation speed of the outdoor blower 4, clogging determination with higher reliability can be performed. In the case of the cooling operation, when the outside air temperature becomes high, the heat exchange in the outdoor heat exchanger cannot be sufficiently performed, and the compressor 7 enters an overload operation state.
The temperature of the discharge pressure increases. Accordingly, the discharge / condensation temperature difference also increases. In other words, the discharge /
If the set value of the condensation temperature difference is changed, clogging can be determined with higher reliability. Therefore, by setting the set value of the discharge / condensation temperature difference according to the outside air temperature at each level and the number of rotations of the outdoor blower at each level, clogging in various operating states can be determined.

(Embodiment 2) As described above, the outside air temperature,
Instead of providing a set value for the discharge / condensation temperature difference according to the rotation speed of the outdoor blower 4, the microcomputer 11 is provided with a set value for the discharge temperature according to the outside air temperature. Outdoor heat exchanger 1
In the case where 3 is clogged, the heat exchange in the outdoor heat exchanger 13 cannot be sufficiently performed, and as shown in FIG. 3, the discharge temperature rises as the discharge pressure rises. When the discharge temperature exceeds the set value of the microcomputer 11, the outdoor heat exchanger 13 is determined to be clogged, and the clogging indicator lamp 19 is turned on. At this time, by setting the set value of the discharge temperature in accordance with the outside air temperature of each level, it is possible to reliably determine clogging in various operation states.

(Embodiment 3) Instead of providing set values for the outside air temperature and the discharge / condensation temperature difference according to the rotation speed of the outdoor blower 4 as in the first embodiment, the microcomputer 11 controls the outside air temperature according to the outside air temperature. Set the set value of the discharge pressure. When the outdoor heat exchanger 13 is clogged, heat exchange in the outdoor heat exchanger 13 cannot be sufficiently performed, and the discharge pressure increases as shown in FIG. When the discharge pressure exceeds the set value of the microcomputer 11, the outdoor heat exchanger 13 is determined to be clogged, and the clogging indicator lamp 19 is turned on. At this time, by providing a plurality of set values of the discharge pressure according to the outside air temperature, it is possible to reliably determine clogging in various operation states.

(Embodiment 4) Instead of providing set values for the outside air temperature and the discharge / condensation temperature difference according to the rotation speed of the outdoor blower 4 as in the first embodiment, the microcomputer 11 Set a set value for the operating current of the compressor. When the outdoor heat exchanger 13 is clogged, heat exchange in the outdoor heat exchanger 13 cannot be performed sufficiently, and the discharge pressure increases. As a result, the compressor 7 is overloaded, and the operating current of the compressor increases as shown in FIG. When the operation current exceeds the set value of the microcomputer 11, the outdoor heat exchanger 13 is determined to be clogged, and the clogging indicator lamp 19 is turned on. At this time, clogging can be reliably determined in various operating states by providing a plurality of set values for the operating current of the compressor in accordance with the outside air temperature at each level.

(Embodiment 5) Instead of providing set values for the outside air temperature and the discharge / condensation temperature difference according to the rotation speed of the outdoor blower 4 as in the first embodiment, the microcomputer 11 controls the microcomputer 11 according to the outside air temperature. Set a value for the wind speed of the outdoor blower. When the outdoor heat exchanger 13 is clogged,
The resistance of the outdoor heat exchanger 13 increases, and as shown in FIG. 3, the wind speed of the outdoor blower 4 decreases. When the wind speed is lower than the set value of the microcomputer 11, the outdoor heat exchanger 13 is determined to be clogged, and the clogging indicator lamp 19 is turned on.
At this time, by providing a plurality of set values of the outdoor blower wind speed according to the outside air temperature at each level, it is possible to reliably determine clogging in various operation states.

(Embodiment 6) As described in the above embodiments, when it is determined that the outdoor heat exchanger 13 is clogged, the rotation speed of the outdoor blower 4 is increased,
Heat exchange in the outdoor heat exchanger 13 is promoted, and stable refrigeration cycle control can be performed.

(Embodiment 7) As described in each of the above embodiments, when it is determined that the outdoor heat exchanger 13 is clogged, the refrigerant is circulated by operating the indoor expansion valve 10 in the opening direction. By increasing the amount, stable refrigeration cycle control can be performed.

(Embodiment 8) A motor capable of rotating in the reverse direction is provided as a motor for driving the outdoor blower 4. As described in each of the above embodiments, when the outdoor heat exchanger 13 is determined to be clogged, the outdoor blower 4 is rotated in the reverse direction to remove the cause of the heat exchanger clogging, and a stable refrigeration cycle Control can be performed.

[0021]

According to the present invention, a method for controlling an air conditioner is provided by detecting a refrigerant discharge temperature, a refrigerant condensing temperature, an outside air temperature, and a rotation speed of a blower, and determining a temperature difference between the refrigerant discharge temperature and the refrigerant condensing temperature. If the calculated temperature difference exceeds an allowable value, that is, the allowable value of the temperature difference obtained in advance with respect to the outside air temperature and the number of rotations of the blower in a state where the ventilation passage of the condenser is clogged, the condenser is clogged. Thus, it is configured to display the clogging, so that it is possible to take a measure to continue the operation before the protection device of the air conditioner operates. As this measure, the refrigeration cycle can be stabilized by increasing the rotation speed of the blower or operating the expansion mechanism in the opening direction.

Also, instead of judging clogging based on the above-described outside air temperature and the difference between the discharge / condensation temperature with respect to the blower,
Even if the control method of the air conditioner is configured to determine the clogging by providing an allowable value for the refrigerant discharge temperature, the refrigerant discharge pressure, or the operating current of the compressor with respect to the outside air temperature with respect to the outside air temperature, protection of the air conditioner It is possible to take measures to continue the operation before the device is operated, and to stabilize the refrigeration cycle by operating the blower or the expansion mechanism as described above.

Also, instead of judging clogging based on the above-mentioned outside air temperature and the discharge / condensation temperature difference with respect to the blower,
The control method of the air conditioner is configured to determine the clogging by providing an allowable value for the wind speed with respect to the fan rotation speed,
By reversing the blower at the time of clogging and removing dust accumulated on the condenser, the refrigeration cycle can be stabilized.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram for realizing a control method of an air conditioner of the present invention.

FIG. 2 is a refrigeration cycle system diagram of the air conditioner.

FIG. 3 is a diagram showing changes in refrigerant discharge temperature, refrigerant condensation, discharge pressure, and the like under a constant outside air temperature due to clogging of an outdoor heat exchanger.

FIG. 4 is a diagram showing set values of a refrigerant discharge / condensation temperature difference according to an outside air temperature and a rotation speed of a blower due to clogging of an outdoor heat exchanger.

FIG. 5 is a diagram illustrating clogging of an outdoor heat exchanger.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 outdoor air thermistor 2 discharge refrigerant thermistor 3 condensed refrigerant thermistor 4 outdoor blower 5 thyristor 6 pressure sensor 7 compressor 8 current sensor 9 wind speed sensor 10 indoor expansion valve 11 microcomputer 12 control board 13 outdoor heat exchanger 14 indoor heat exchanger 15 Indoor blower 16 Accumulator 17 Outdoor unit 18 Indoor unit 19 Indicator lamp 20 Fin 21 Refrigerant coil 22 Dust / dust

Claims (5)

[Claims] 1. A control method for an air conditioner comprising a compressor, a condenser, an expansion mechanism, and an evaporator, which constitutes a refrigeration cycle, comprising: a discharge temperature of a refrigerant discharged from the compressor, a refrigerant condensed in the condenser. The condensing temperature, the outside air temperature around the condenser, and the rotation speed of a blower that blows outside air to the condenser are detected, and the temperature difference between the discharge temperature and the condensing temperature is calculated. When the outside air temperature in the clogged state of the ventilation passage of the condenser exceeds a permissible value obtained in advance with respect to the rotation speed of the blower, it is determined that the condenser is clogged, and a clogging display is displayed. A method for controlling an air conditioner, comprising: 2. The control method for an air conditioner according to claim 1, wherein when the clogging is determined, the rotation speed of the blower is increased to perform stable refrigeration cycle control. 3. The control method for an air conditioner according to claim 1, wherein when the clogging is determined, the expansion mechanism is operated in an opening direction to perform stable refrigeration cycle control. 4. The blower can rotate forward and backward,
The control method for an air conditioner according to claim 1, wherein when the clogging is determined, the blower is rotated in the reverse direction to remove a clogging factor. 5. A control device for an air conditioner constituting a refrigeration cycle comprising a compressor, a condenser, an expansion mechanism and an evaporator, a first temperature detector for detecting an outside air temperature around the condenser, and the compressor. A second temperature detector for detecting a discharge temperature of the refrigerant discharged from the condenser, a third temperature detector for detecting a condensation temperature of the refrigerant condensed in the condenser, and rotation of a blower for blowing outside air to the condenser. A rotation speed detector for detecting the number, a temperature difference between a discharge temperature detected by the second temperature detector and a condensation temperature detected by the third temperature detector, and calculating the calculated temperature difference. In the clogged state of the ventilation passage of the condenser, the outside air temperature, which was previously obtained with respect to the rotation speed of the blower, was compared with an allowable value of a temperature difference between a refrigerant discharge temperature and a condensation temperature, and was calculated. When the temperature difference exceeds the tolerance, A control device for an air conditioner, comprising: a computer that outputs a clogging signal so as to display clogging and increase the rotation speed of the blower.