JPS6128985Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a control circuit for an air conditioner, and is particularly intended to reduce noise generated when switching from cooling operation to dehumidification operation.

There is a trend toward improved comfort in the performance of air conditioners, and as part of this, there is a need to reduce noise and reduce the range of changes in room temperature. In order to reduce the range of change in room temperature, it is necessary to reduce the hysteresis range of temperature control.
FIG. 1 is a characteristic diagram of a temperature control circuit for explaining temperature hysteresis, in which the horizontal axis shows temperature and the vertical axis shows the output level of the temperature control circuit. FIG. 2 is a circuit diagram of a temperature control circuit, in which the voltage of a lead wire 8 divided by a temperature sensor 1 consisting of a temperature sensing element and a resistor 2 is divided by a resistor 3, a variable resistor 4, a resistor 5, and a resistor 2. A comparator 6 compares the voltage with a reference voltage of a lead wire 9 provided by a feedback resistor 7 to perform control. For example, when the voltage of the lead wire 8 is higher than the voltage of the lead wire 9, the output level of the output lead wire 10 becomes a low level L, and at this time, the cooling device 11 connected to the lead wire 10 operates. When the voltage of the lead wire 8 is higher than the voltage of the lead wire 9, the output level of the output lead wire 10 becomes high level H, and the cooling device 1
The air conditioner 1 is configured to stop the cooling operation. In addition, in the circuit of FIG. 2, the lead wire 8
The voltage increases and decreases depending on the change in the resistance value of the temperature sensor 1, and as the temperature of the indoor air increases, the resistance value decreases and the voltage increases, and as the temperature decreases, the resistance value increases and the voltage decreases. In addition, the lead wire 9
Because of the feedback resistor 7, the voltage increases and decreases depending on the output level of the output lead wire 10, and increases when the output level is high level H and decreases when the output level is low level L.

Now, suppose that the temperature gradually rises from state A shown in FIG. When T ₂ is exceeded, the voltage on lead 8 becomes higher than the voltage on lead 9, and the level on lead 10 becomes low level L.
become. If the temperature further rises, the state B will be reached, but when the level of the lead wire 10 reaches the low level L, the air conditioner 11 will operate, so the temperature will normally drop. Next, when the temperature decreases from state B, at this time the output level of the lead wire 10 is low level L, so the voltage of the lead wire 9 decreases, and the temperature increases.
Even at _T2 , the voltage of the lead wire 8 is higher, and the temperature decreases while the output level is maintained at the low level L, passing through state C and decreasing to temperature _T1 . When the voltage of the lead wire 8 becomes equal to the voltage of the lead wire 9 at temperature _T1 , the output level of the lead wire 10 returns to the high level H again. When the temperature further decreases, the state becomes D, but when the output level reaches the high level H, the operation of the air conditioner 11 is stopped, so the room temperature rises again. When the temperature rises from state D,
At this time, since the lead wire 9 is rising, the output level passes through the temperature _T1 while being held at the high level H, and returns to the state A again.

Temperature control by an air conditioner is performed by repeating the above-mentioned cycle, but reducing the temperature hysteresis width reduces the temperature difference between temperatures T ₁ and T ₂ and keeps the indoor air temperature as constant as possible. The aim is to improve comfort by maintaining

In addition to the cooling mode described above, the air conditioner may operate in a dehumidifying mode. In the dehumidifying mode, the operation of the air conditioner 11 is normally switched between cooling operation and dehumidifying operation. For example, when the output level of the lead wire 10 of the comparator 6 is H, the dehumidifying operation is performed, and when the level is In the case of L, cooling operation is performed. Switching between dehumidifying operation and cooling operation in the dehumidification mode is performed by a three-way valve installed in the indoor unit, and when switching this three-way valve, especially when switching from cooling operation to dehumidifying operation, a loud noise is generated. ,
When the temperature hysteresis width of an air conditioner is made small, switching from cooling operation to dehumidification operation is frequently performed in the dehumidification mode, and accordingly, a loud noise is generated from the three-way valve, causing discomfort to the user.

A further supplementary explanation will be added regarding the generation of noise due to 3-way valve switching.

Fig. 3 shows a principle diagram of the operation of the air conditioner during cooling operation and dehumidification operation. In the figure, the left side of the dashed line shows the outdoor unit 12, and the right side shows the indoor unit 13.

During cooling operation, the check valve 19 is closed and the three-way valve 20 is open between Y and Z. The high-temperature, high-pressure gaseous refrigerant 22 (the path of the refrigerant during cooling operation is shown by a solid arrow) compressed by the compressor 14 is cooled by the outdoor heat exchanger 15, condensed and liquefied, and then used for cooling. The pressure is reduced through the capillary 16 and becomes low temperature and low pressure, which is then sent to the cooler 17 of the indoor heat exchanger.
and reheater (acts as a cooler in cooling operation)
18, the refrigerant cools and evaporates the air around the cooler 17 and reheater 18, and returns to the compression line 14 again to complete one cycle.

On the other hand, in the dehumidifying operation, the check valve 19 is opened, and the three-way valve changes its valve position so that the X-Y gap is open. The gaseous refrigerant 23 compressed by the compressor 14 (the path of the refrigerant during dehumidification operation is indicated by a broken line arrow) is cooled and condensed by the outdoor heat exchanger 15, and then passed through the check valves 19 and 3. It is sent to the reheater 18 through the diverter valve 20. Here, the refrigerant condenses and liquefies while dissipating further heat, and while this refrigerant passes through the dehumidification capillary 21, it is depressurized and enters the cooler 17, where it cools the air around the cooler 17 and evaporates, and the refrigerant is evaporated again. Returning to the compressor 14, one cycle is completed. When the air is cooled by the cooler 17,
The moisture contained in the air turns into dew and cools the cooler 1.
7 and moisture is removed. When this cooled and dehumidified air then passes around the reheater 18, it is heated by the heat radiated from the reheater 18, and after being warmed up again to the original temperature, it becomes dry air. He is sent indoors. Therefore, in the case of dehumidifying operation, the temperature of the air hardly decreases, only the humidity decreases.

As mentioned above, in the dehumidification mode, the dehumidification operation and the cooling operation are alternately performed, so the reheater 18 operates as a cooler during the cooling operation,
During dehumidification operation, it operates as a reheater. Reheater 1
8 is operating as a cooler, the pressure of the refrigerant in this cooler is decreasing, and when switching from cooling operation to dehumidification operation, check valve 19 and three-way valve 20
High-pressure refrigerant enters the reheater 18 through the refrigerant, and due to the pressure difference of the refrigerant, the refrigerant expands rapidly and generates loud noise. Therefore, if the temperature hysteresis width is made smaller, switching from cooling operation to dehumidification operation often occurs during dehumidification mode.
Noise will be generated each time.

The purpose of this invention is to provide an air conditioner that performs comfortable control with a small range of change in indoor temperature when in cooling mode, and generates less noise from the reheater when in dehumidification mode. The objective is to be achieved by switching the temperature hysteresis in the mode using a changeover switch, particularly by reducing the temperature hysteresis width in the cooling mode and increasing the temperature hysteresis width in the dehumidification mode.

The present invention will be explained below based on the drawings. Fourth
The figure is a circuit diagram of the temperature control circuit of the present invention. 24 is a changeover switch for the user to select between cooling and dehumidification mode; when terminal a is connected to terminal b, it is connected to dehumidification mode and terminal c is connected. and operation in cooling mode is performed. Reference numeral 25 denotes a sub-changeover switch that is operated by movement of the changeover switch 24. When the terminal a of the changeover switch 24 is connected to the terminal b, the terminal d of the sub-changeover switch 25 is connected to the terminal e, and the changeover switch is When the terminal a is connected to the terminal c, the terminal d of the sub changeover switch 25 is connected to the terminal. A feedback resistor 26 is connected in parallel to the feedback resistor 7 when the terminal d of the sub-changeover switch 25 is connected to the terminal e.

In this invention, when the feedback resistor 26 is connected, the lead wire 9
The temperature hysteresis is switched by paying attention to the change in voltage.

In the case of the cooling mode in which the terminal a of the changeover switch 24 is connected to the terminal c and therefore the terminal d of the sub changeover switch 25 is connected to the terminal, the voltage of the lead wire 9 is equal to the power supply voltage Vcc and the output voltage. The voltage of the lead wire 10 is controlled by resistors 3 and 5, and variable resistor 4.
Furthermore, the voltage is divided by feedback resistor 7,
This circuit is the same as the circuit shown in FIG. 2, and provides comfortable temperature control with small temperature hysteresis.

In the dehumidification mode in which terminal a of the changeover switch 24 is connected to terminal b and therefore terminal d of the sub changeover switch 25 is connected to terminal e,
The voltage of the lead wire 9 is a voltage obtained by dividing the power supply voltage Vcc and the voltage of the output lead wire 10 by the resistors 3 and 5, the variable resistor 4, the feedback resistor 7, and the feedback resistor 26. In this case, since the feedback resistor 26 is connected in parallel to the feedback resistor 7, the lead wire 1
The amount of feedback from 0 to the lead wire increases, and lead wire 1
The change in the voltage of the lead wire 9 increases as the voltage of the lead wire 9 changes.

FIG. 5 is a characteristic diagram of the temperature control circuit in the dehumidification mode. Now, suppose that the output level of the lead wire 10 is a high level H and the temperature gradually rises from the state A in which the cooling device 11 is performing dehumidification operation. In this case, the voltage of the lead wire 9 is is higher than when it is not connected, and at temperature _T2 , the voltage of lead wire 8 is lower than the voltage of lead wire 9, so no change occurs in the level of lead wire 10, and dehumidification operation continues. be done. At temperature T ₃ , lead wire 8 and lead wire 9
When the voltages become equal, the level of the lead wire 10 becomes a low level L. When the level of the lead wire 10 reaches the low level L, the cooling device 11 switches from the dehumidifying operation to the cooling operation as described above. When the cooling operation is performed, the indoor temperature decreases. temperature at this time
At T ₃ , the output level of lead wire 10 is low level L, so the voltage of lead wire 9 is decreasing, and the voltage of lead wire 8 is higher, so the output level remains at low level L. Temperature decreases.
Even when the temperature further decreases and reaches temperature T ₁ , the amount of feedback increases because the resistor 26 is connected, and the voltage on the lead wire 9 is lower than when the resistor 26 is not connected. The voltage of the lead wire 8 is higher, and no change occurs in the level of the lead wire 10, and the cooling operation is continued. When the temperature further decreases and reaches the temperature _T4 , the voltages of the lead wires 8 and 9 become equal, and the level of the lead wire 10 becomes a high level H. When the level of the lead wire 10 becomes high level, the cooling device 11 switches to dehumidifying operation again. In this state, if there is no change in the temperature of the indoor air, the dehumidifying operation is continued, but if the temperature of the indoor air rises, the state returns to state A.

As described above, the noise generated in the dehumidification mode is generated when the operating state of the cooling device 11 is switched from the cooling operation to the dehumidification operation. When the width of the temperature hysteresis is increased, the frequency of switching from dehumidifying operation to cooling operation is reduced, so the frequency of switching from cooling operation to dehumidifying operation is also reduced, and the generation of noise can be reduced.

In addition, in the above description, it was explained that the output level of the lead wire 10 changes when the voltages of the lead wire 8 and the lead wire 9 become equal.
It is also possible to configure the circuit so that the output level of the lead wire 10 changes when the difference between the voltages of the lead wire 9 and the lead wire 9 becomes constant.

As explained above, in the control circuit of the present invention, comfortable control with small temperature hysteresis is performed in the cooling mode, and temperature hysteresis is suppressed in the dehumidification mode by connecting a resistor in parallel to the feedback resistor. Since it can be made larger, the frequency of switching from cooling operation to dehumidification operation can be reduced, and control can be performed to reduce the generation of noise when switching from cooling operation to dehumidification operation.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram to explain temperature hysteresis, Fig. 2 is a circuit diagram of a conventional temperature control circuit, Fig. 3 is a principle diagram to explain the operation of air conditioner cooling operation and dehumidification operation, and Fig. 4 The figure is a circuit diagram showing an embodiment of the temperature control circuit according to the present invention, and FIG. 5 is a characteristic diagram of temperature hysteresis during dehumidification operation according to the present invention. 1... Temperature detector, 2, 3, 5... Low resistance, 4...
...Variable resistor, 6...Comparator, 7, 26...Feedback resistor, 8, 9, 10...Lead wire, 24...Main changeover switch, 25...Sub changeover switch.

Claims (1)

[Scope of utility model registration request] It is equipped with a compressor, a heat exchanger, a cooler, a reheater, a three-way valve, and first, second, and third capillary tubes, and when operating in cooling mode, the refrigerant compressed by the compressor is is the heat exchanger first capillary tube,
The water is circulated sequentially through the cooler, and is also circulated through a second capillary tube connected in parallel to the first capillary tube and the cooler, a reheater, and a three-way valve, during dehumidification mode operation. The system includes a cooling system in which refrigerant compressed by a compressor sequentially circulates through a heat exchanger, a three-way valve, a reheater, a third capillary tube, and a cooler, and a cooling mode operation and a dehumidification mode operation. a changeover switch for switching, a temperature detector for detecting room temperature and deriving a detected voltage, a reference voltage generation means for deriving a predetermined reference voltage;
The control circuit includes a comparator that derives an output signal to the output lead wire when the detection voltage and the reference voltage are introduced and the difference between the detection voltage and the reference voltage reaches a predetermined value. , an air conditioner in which a cooling device is operated by an output signal of a control circuit, comprising: a sub-switch switch that operates in conjunction with the switch; and a plurality of sub-switches for feeding back the output signal to the reference voltage generating means. A control circuit for an air conditioner, characterized in that the temperature hysteresis in the dehumidification mode is selected to be larger than the temperature hysteresis in the cooling mode by the sub-switch. .