JP3117321B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a dry operation function.

[0002]

2. Description of the Related Art An air conditioner is provided with two indoor heat exchangers to perform a cooling operation by functioning both indoor heat exchangers as an evaporator, and to reduce the pressure between both indoor heat exchangers. In some cases, a dry operation is performed by allowing one indoor heat exchanger to function as an evaporator and the other indoor heat exchanger to function as a reheater (condenser) with a heater interposed. That is,
In the dry operation, the air that has been cooled and dehumidified by the evaporator is reheated by the reheater, reaches a normal temperature, and is blown into the room.

In such an air conditioner, the amount of sensible heat and the amount of latent heat (= dehumidification amount) can be changed by controlling the operating frequency F (Hz) of the compressor, as shown in FIG. The amount of sensible heat can be changed by controlling the rotation speed N (rpm) of the fan. In other words, by controlling the number of revolutions N of the outdoor fan, the heat radiation amount of the refrigerant in the outdoor heat exchanger is changed, and the cool dry, the isothermal dry, and the warm dry with different dry air temperatures are selectively executed. Can be.

[0004]

Among the temperature and humidity controls by the dry operation as described above, the humidity (latent heat) is controlled by the operating frequency F of the compressor, and the temperature (sensible heat) is controlled by the rotation of an outdoor fan. This control is based on the number N, and is basically a humidity-priority control method.

[0005] Therefore, for example, when the amount of dehumidification is reduced, the operating frequency F of the compressor is lowered. In this case, since the amount of sensible heat is originally small, only the adjustment of the rotation speed N of the outdoor fan naturally limits the control of the room temperature.

[0006] The present invention has been made in view of the above circumstances,
The air conditioner according to any one of claims 1 and 2 has an object to enable sufficient control of not only humidity but also temperature during a dry operation to improve comfort.

[0007]

According to a first aspect of the present invention, an air conditioner includes a compressor, an outdoor heat exchanger, a first decompressor, a first indoor heat exchanger, a second decompressor, and a second indoor heat exchanger. A connected refrigeration cycle, an outdoor fan for circulating outdoor air to the outdoor heat exchanger, and a refrigerant discharged from the compressor to the outdoor heat exchanger, the first decompressor, the first indoor heat exchanger, and the second indoor heat exchanger. Means for performing a cooling operation by returning the refrigerant to the compressor through an outdoor heat exchanger, a first indoor heat exchanger, a second decompressor,
Means for passing through the indoor heat exchanger and returning to the compressor to perform a dry operation, an indoor temperature sensor for detecting the indoor temperature, an indoor humidity sensor for detecting the indoor humidity, and according to the detected humidity of the indoor humidity sensor during the dry operation. Means for obtaining a correction amount for the current capacity of the compressor by controlling the capacity by the correction amount, and obtaining a correction amount for the current rotational speed of the outdoor fan in accordance with the temperature detected by the indoor temperature sensor during the dry operation. Means for controlling only the rotation speed, and when the correction amount for the rotation speed of the outdoor fan during the dry operation is a change in the increasing direction, if the rotation speed of the outdoor fan is at a predetermined maximum value, the rotation speed is directly changed to the compressor speed. Means for increasing the operating frequency by a predetermined value.

[0008] The air conditioner according to claim 2 is a compressor, an outdoor heat exchanger, a first decompressor, a first indoor heat exchanger, a second decompressor,
A refrigeration cycle to which the second indoor heat exchanger is connected, an outdoor fan that circulates outdoor air through the outdoor heat exchanger, and an outdoor heat exchanger that discharges refrigerant from the compressor, a first decompressor, a first indoor heat exchanger, Means for returning to the compressor through the second indoor heat exchanger to perform a cooling operation, and for discharging refrigerant discharged from the compressor to an outdoor heat exchanger, a first indoor heat exchanger, a second decompressor, and a second indoor heat exchanger Means for performing a dry operation by returning to the compressor, an indoor temperature sensor for detecting the indoor temperature, an indoor humidity sensor for detecting the indoor humidity, and a compressor for the dry operation in accordance with the detected humidity of the indoor humidity sensor. Means for obtaining a correction amount for the current capability and controlling the capability by the correction amount; and obtaining a correction amount for the current rotational speed of the outdoor fan according to the temperature detected by the indoor temperature sensor during the dry operation, and calculating the rotational speed by the correction amount. Control means and A means for increasing the operating frequency of the compressor by a predetermined value if the rotational speed of the outdoor fan is at a predetermined minimum value when the correction amount for the rotational speed of the outdoor fan is a change in the decreasing direction during the operation. Prepare.

[0009]

In the air conditioner of the first aspect, during dry operation, a correction amount for the current capacity of the compressor is obtained in accordance with the humidity detected by the indoor humidity sensor, and the capacity is controlled by the correction amount. At the same time, a correction amount for the current rotational speed of the outdoor fan is obtained in accordance with the temperature detected by the indoor temperature sensor, and the rotational speed is controlled by the corrected amount, so that the temperature of the dry air is different between a cool dry, an isothermal dry, and a warm dry. Is selectively executed. When the correction amount with respect to the rotation speed of the outdoor fan is a change in the increasing direction, if the rotation speed of the outdoor fan is at a predetermined maximum value, the rotation frequency directly increases the operating frequency of the compressor.

In the air conditioner of the second aspect, during dry operation, a correction amount for the current capacity of the compressor is obtained in accordance with the humidity detected by the indoor humidity sensor, and the capacity is controlled by the correction amount. At the same time, a correction amount for the current rotational speed of the outdoor fan is obtained in accordance with the temperature detected by the indoor temperature sensor, and the rotational speed is controlled by the corrected amount, so that the temperature of the dry air is different between a cool dry, an isothermal dry, and a warm dry. Is selectively executed. Then, when the correction amount with respect to the rotation speed of the outdoor fan is a change in the decreasing direction, if the rotation speed of the outdoor fan is at a predetermined minimum value, the rotation frequency directly increases the operating frequency of the compressor.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, an outdoor heat exchanger 3 is connected to a discharge port of a compressor 1 via a four-way valve 2. This outdoor heat exchanger 3 is connected to a first pressure reducer, for example, an electric expansion valve 4.
The first indoor heat exchanger 5 is connected via the. The first indoor heat exchanger 5 is provided with a second decompressor, for example, a capillary tube 6.
, A second indoor heat exchanger 7 is connected, and a two-way valve 8 is connected in parallel with the capillary tube 6. And
The second indoor heat exchanger 7 is connected to the suction port of the compressor 1 via the four-way valve 2.

The electric expansion valve 4 is a pulse motor valve (PMV) whose opening continuously changes in accordance with the number of input drive pulses. The compressor 1 is a variable capacity compressor, and a drive motor is connected to the inverter circuit 21. The inverter circuit 21 rectifies the voltage of the commercial AC power supply 20, converts the rectified voltage into a voltage having a frequency corresponding to a command from the outdoor control unit 30, and outputs the voltage. This output is the driving power of the compressor motor.

An outdoor fan 11 is provided near the outdoor heat exchanger 3. The outdoor fan 11 circulates outside air to the outdoor heat exchanger 3, and the motor 11M is connected to the phase control circuit 2
2 is connected. The phase control circuit 22 controls the phase of energization from the commercial AC power supply 20 to the motor 11M according to a command from the outdoor control unit 30. By this phase control, the rotation speed N of the outdoor fan 11 can be changed.

The indoor fan 1 is located near the indoor heat exchangers 5 and 7.
2 are provided. The indoor fan 12 circulates indoor air through the indoor heat exchangers 5 and 7, and the motor 12M is connected to the commercial AC power supply 20 via the tap switching circuit 23. The tap switching circuit 23 includes speed switching taps H (high speed), M (medium speed), L (low speed), L- (very low speed), UL
(Ultra low speed), and performs tap switching according to a command from the indoor control unit 40.

The outdoor control unit 30 and the indoor control unit 40
Each is composed of a microcomputer and its peripheral circuits, and is interconnected by a serial signal line to control the entire air conditioner.

The outdoor control unit 30 is connected with the four-way valve 2, the electric expansion valve 4, the inverter circuit 21, and the phase control circuit 22. Two-way valve 8, tap switching circuit 2
3. An indoor temperature sensor 41, an indoor humidity sensor 42, and a remote control type operation device (hereinafter, abbreviated as a remote control) 43 are connected.

The outdoor control unit 30 and the indoor control unit 40
Has the following functional means. [1] The compressor 1 is operated, and the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the electric expansion valve 4, the first indoor heat exchanger 5, the two-way valve 8 (open), The second indoor heat exchanger 7,
Means for returning to the compressor 1 through the four-way valve 2 and performing a cooling operation.

[2] During the cooling operation, the room temperature Ta detected by the room temperature sensor 41 and the set temperature T by the remote controller 43
means for controlling the operating frequency F of the compressor 1 (the output frequency of the inverter circuit 11) in accordance with the difference T (= Ta−Ts) from s.

[3] The compressor 1 is operated, and the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the outdoor heat exchanger 3, the electric expansion valve 4, the first indoor heat exchanger 5, the capillary tube 6 (two Means for performing a dry operation by returning to the compressor 1 through the second indoor heat exchanger 7 and the four-way valve 2 and fully opening the electric expansion valve 4.

[4] During dry operation, indoor humidity sensor 42
The difference H (= Ha−Hs) between the indoor humidity Ha detected by the remote controller 43 and the set humidity Hs at the remote controller 43 and the variation ΔH of the difference H are obtained, and the compressor is obtained by fuzzy inference using both as antecedents. 1 correction amount Δ to current operating frequency F
A means for obtaining F and controlling the operating frequency F by the correction amount ΔF.

[5] Indoor temperature sensor 41 during dry operation
The difference T (= Ta−Ts) between the indoor temperature Ta detected by the remote controller 43 and the set temperature Ts on the remote controller 43 and the variation ΔT of the difference T are obtained, and the outdoor fan is determined by fuzzy inference using both as antecedents. A correction amount ΔN for the current 11 rotation speed N (based on the phase control of the phase control circuit 22) is obtained,
A means for controlling the number of revolutions N by the correction amount ΔN, thereby adjusting the amount of sensible heat and changing the temperature of the dry air.

[6] During the dry operation, when the correction amount ΔN with respect to the rotation speed N of the outdoor fan 11 is a change in the increasing direction, if the rotation speed N of the outdoor fan 11 is at a predetermined maximum value Nmax, the rotation is performed. The number N (= Nmax) is a means for increasing the operating frequency F of the compressor 1 by a predetermined value ΔFn.

[7] During the dry operation, when the correction amount ΔN with respect to the rotation speed N of the outdoor fan 11 is a change in a decreasing direction, the rotation speed N of the outdoor fan 11 is reduced to a predetermined minimum value Nmin (including stop). , The rotation speed N (= Nmin
) Indicates that the operating frequency F of the compressor 1 is changed to a predetermined value ΔFn.
Means to enhance.

[8] The compressor 1 is operated by switching the four-way valve 2, and the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2, the second indoor heat exchanger 7, the two-way valve 8 (open), the first Indoor heat exchanger 5,
Means for returning to the compressor 1 through the electric expansion valve 4, the outdoor heat exchanger 3, and the four-way valve 2, and performing a heating operation.

[9] During the heating operation, the set temperature Ts by the remote controller 43 and the room temperature T detected by the room temperature sensor 41
means for controlling the operating frequency F of the compressor 1 in accordance with the difference T (= Ts−Ta) from “a”.

[10] Means for selecting one of the cooling operation, the dry operation, and the heating operation according to the setting mode of the remote controller 43. [11] When the dry operation is set by the remote controller 43, execution of the cooling operation is performed based on the room temperature Ta and the room humidity Ha and the operation mode setting conditions previously determined in the internal memory.
Means for selecting execution of a dry operation or execution of a ventilation operation.

Next, the operation of the above configuration will be described. When the dry operation is set by the remote controller 43, the indoor temperature Ta
The execution of the cooling operation, the execution of the dry operation, or the execution of the air blowing operation is selected based on the indoor humidity Ha detected by the indoor humidity sensor 23 and the operation mode selection condition predetermined in the internal memory of the control unit 20 in advance. .

That is, if the room temperature Ta is sufficiently higher than the set temperature Ts on the remote controller 43, the cooling operation is executed, and if the room temperature Ta falls within a predetermined range centered on the set temperature Ts, the dry operation is performed. Is executed and the room temperature T
When a falls below the set temperature Ts and deviates from the predetermined range, the air blowing operation is executed.

In the cooling operation, the operation of the compressor 1 and the four-way valve 2
Inactive (neutral state), throttle of the electric expansion valve 4,
Opening of the two-way valve 8, operation of the outdoor fan 11, indoor fan 1
Operation 2 is set.

In this case, the refrigerant is discharged from the compressor 1,
It enters the outdoor heat exchanger 3 through the four-way valve 2. In the outdoor heat exchanger 3, the refrigerant releases heat to the outside air and liquefies. The refrigerant that has passed through the outdoor heat exchanger 3 is decompressed by the electric expansion valve 4 so as to be easily vaporized, and enters the first indoor heat exchanger 5. The refrigerant that has entered the first indoor heat exchanger 5 also flows into the second indoor heat exchanger 7 through the two-way valve 8. Indoor heat exchanger 5,
In 7, the refrigerant takes heat from the room air and evaporates. The refrigerant having passed through the indoor heat exchangers 5 and 7 returns to the compressor 1 through the four-way valve 2.

In this manner, the refrigerant flows in the direction indicated by the solid line arrows in FIG. 1 to form a cooling cycle, and the outdoor heat exchanger 3 functions as a condenser and the indoor heat exchangers 5 and 7 both function as evaporators. Is cooled.

In the dry operation, the operation of the compressor 1, the non-operation of the four-way valve 2, the full opening of the electric expansion valve 4, the closing of the two-way valve 8, the operation of the outdoor fan 11, and the operation of the indoor fan 12 are set. You.

In this case, the refrigerant is discharged from the compressor 1,
It passes through the four-way valve 2 and the outdoor heat exchanger 3 and from there through the fully open electric expansion valve 4 into the first indoor heat exchanger 5. In the first indoor heat exchanger 5, the refrigerant releases heat to the indoor air and liquefies. The refrigerant that has passed through the first indoor heat exchanger 5 is decompressed by the capillary tube 6 so as to be easily vaporized, and enters the second indoor heat exchanger 7. In the second indoor heat exchanger 7, the refrigerant takes heat from indoor air and evaporates.
The refrigerant that has passed through the second indoor heat exchanger 7 returns to the compressor 1 through the four-way valve 2.

In this way, the refrigerant flows in the direction indicated by the solid line arrows as in the cooling to form a dry cycle, the outdoor heat exchanger 3 is a condenser, the indoor heat exchanger 5 is also a condenser (reheater), and the indoor heat The exchanger 7 acts as an evaporator.

Therefore, the indoor air is cooled by the indoor heat exchanger 7, and the moisture contained in the indoor air becomes a drain and adheres to the indoor heat exchanger 7. The dry air cooled and dehumidified by the indoor heat exchanger 7 is heated by the indoor heat exchanger 5, which is a reheater, and is blown into the room.

During the dry operation, the indoor humidity Ha detected by the indoor humidity sensor 42 and the set humidity H
The difference H (= Ha−Hs) with respect to s and the change amount ΔH of the difference H are obtained, and the correction amount Δ to the current operating frequency F of the compressor 1 is obtained by fuzzy inference with both of them as antecedents.
F is required. Then, the operating frequency F is actually controlled by the obtained correction amount ΔF.

For example, when the indoor humidity Ha is high, the operating frequency F of the compressor 1 is set high, and the indoor humidity Ha
Is decreased, the operating frequency F of the compressor 1 is gradually reduced.

During the dry operation, the indoor temperature sensor 4
The difference T (= Ta−Ts) between the room temperature Ta detected at 1 and the set temperature Ts at the remote controller 43 and the variation ΔT of the difference T are obtained, and the two are antecedent parts by fuzzy inference. A correction amount ΔN for the current rotational speed N of the outdoor fan 11 (based on the phase control of the phase control circuit 22) is obtained. Then, the rotational speed N is actually controlled by the obtained correction amount ΔN. By this control, the outdoor heat exchanger 3
The amount of heat radiation of the refrigerant in the air is adjusted, that is, the amount of sensible heat is adjusted, and the temperature of the dry air is selected according to the difference T between the room temperature Ta and the set temperature Ts. Is executed.

Specifically, when the room temperature Ta is felt to be relatively high, a cool dry is selected. In this cool dry mode, the outdoor fan 11 is set at a higher speed, and the amount of refrigerant radiated by the outdoor heat exchanger 3 increases. The amount of heat released increases the amount of heat applied to the reheater (indoor heat exchanger 5), and the dry air is blown into the room in a cold state without being heated much.

When the room temperature Ta is close to the set temperature Ts, the isothermal drying is selected. In this isothermal drying,
The outdoor fan 11 is set at a medium speed, and the amount of refrigerant radiated by the outdoor heat exchanger 3 does not increase so much. Therefore,
The dry air is blown into the room to such an extent that it is warmed to the same temperature as the room temperature Ta.

When the room temperature Ta is felt to be low, the warm dry is selected. In this warm dry mode, the outdoor fan 11 is set at a low speed, and the amount of refrigerant radiated by the outdoor heat exchanger 3 is reduced. The amount of heat applied to the reheater (the indoor heat exchanger 5) is increased by an amount corresponding to the reduced amount of heat release, and the dry air is sufficiently warmed and blown into the room.

As described above, by controlling the number of revolutions N of the outdoor fan 11 to adjust the temperature of the dry air, it is possible to moderate the fluctuation of the indoor temperature, which is comfortable. The control values of the operating frequency F and the number of revolutions N are set by the indoor control unit 40, and the serial signal codes S ₀ and S ₀ , based on the set values and the predetermined code setting conditions shown in FIG. S ₁ ,..., S ₁₅ are selected, and the codes are sent to the outdoor control unit 30 to actually execute the control.

By the way, in the dry operation, as shown in FIG. 2, the correction amount ΔN with respect to the rotation speed N of the outdoor fan 11 is sequentially monitored. When the correction amount ΔN is a change in the increasing direction (ΔN> 0), if the rotation speed N has reached a predetermined maximum value Nmax (N ≧ Nmax), the further decrease in the indoor temperature is only by the rotation speed control. The operation frequency F of the compressor 1 is increased by a predetermined value ΔFn while maintaining the rotation speed N (= Nmax) as it is determined that the operation is impossible. ΔFn
Corresponds to one step of the normal operation frequency control.

The increase in the operating frequency F of the compressor 1 compensates for the shortage of the sensible heat and makes it possible to lower the room temperature Ta. That is, let alone humidity control,
Sufficient control is possible for the temperature that has the greatest effect on comfort, and comfort can be improved.

When the correction amount ΔN is a change in a decreasing direction (ΔN <0), the rotation speed N is reduced to a predetermined minimum value Nmi.
n (including stop) (N ≦ Nmin)
The operating frequency F of the compressor 1 is increased by a predetermined value ΔFn while the rotation speed N (= Nmin) is kept unchanged, based on the judgment that the further increase in the room temperature is impossible only by the rotation speed control. ΔFn corresponds to one step of the normal operation frequency control.

As the operating frequency F of the compressor 1 is increased in this manner, the shortfall in the amount of sensible heat is compensated for, and the room temperature Ta can be increased. That is, it is possible to sufficiently control not only the humidity control but also the temperature that has the greatest effect on the comfort, and the comfort can be improved. In addition,
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

[0047]

As described above, according to the present invention, in the air conditioner of the first aspect, when the correction amount with respect to the rotation speed of the outdoor fan is increasing in the dry operation, the air conditioner of the outdoor fan is controlled. If the rotation speed is at the predetermined maximum value,
Since the operating frequency of the compressor is increased by a predetermined value without changing the number of revolutions, sufficient control can be performed not only for the humidity but also for the temperature during the dry operation to improve the comfort.

[0048] The air conditioner according to the second aspect is characterized in that at the time of dry operation,
When the correction amount for the rotation speed of the outdoor fan is a change in the decreasing direction, if the rotation speed of the outdoor fan is at a predetermined minimum value, the rotation speed is directly increased by a predetermined value to increase the operating frequency of the compressor. In addition, it is possible to sufficiently control not only the humidity during the dry operation but also the temperature, thereby improving comfort.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle and a control circuit according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining rotation speed control of the embodiment.

FIG. 3 is a flowchart for explaining operating frequency control of the embodiment.

FIG. 4 is a view showing code setting conditions for a serial signal in the embodiment.

FIG. 5 is a graph showing a relationship among an operation frequency, a sensible heat amount, and a latent heat amount in a general air conditioner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 3 ... Outdoor heat exchanger, 5 ... First indoor heat exchanger, 7 ... Second indoor heat exchanger, 11 ... Outdoor fan, 12 ...
Indoor fan, 30: outdoor control unit, 40: indoor control unit.

Claims (2)

(57) [Claims] 1. A refrigeration cycle to which a compressor, an outdoor heat exchanger, a first decompressor, a first indoor heat exchanger, a second decompressor, and a second indoor heat exchanger are connected, and an outdoor heat exchanger is connected to the outdoor heat exchanger. An outdoor fan for circulating air, and a refrigerant discharged from the compressor passing through an outdoor heat exchanger, a first decompressor, a first indoor heat exchanger, and a second indoor heat exchanger, and returning to the compressor to perform a cooling operation. Means for passing the refrigerant discharged from the compressor through an outdoor heat exchanger, a first indoor heat exchanger, a second decompressor, and a second indoor heat exchanger to return the compressor to a dry operation; An indoor temperature sensor for detecting the indoor humidity, an indoor humidity sensor for detecting the indoor humidity, and during a dry operation, a correction amount for the current capacity of the compressor is obtained according to the detected humidity of the indoor humidity sensor, and the capacity is determined by the correction amount. Means for controlling the room temperature during dry operation. Means for obtaining a correction amount for the current rotational speed of the outdoor fan in accordance with the detected temperature of the outdoor fan, and controlling the rotational speed by the correction amount; and in a dry operation, the correction amount for the rotational speed of the outdoor fan increases. The air conditioner further comprises means for increasing the operating frequency of the compressor by a predetermined value if the rotation speed of the outdoor fan is at a predetermined maximum value when the rotation speed of the outdoor fan is at a predetermined maximum value. 2. A refrigeration cycle to which a compressor, an outdoor heat exchanger, a first decompressor, a first indoor heat exchanger, a second decompressor, and a second indoor heat exchanger are connected, and an outdoor heat exchanger is connected to the outdoor heat exchanger. An outdoor fan for circulating air, and a refrigerant discharged from the compressor passing through an outdoor heat exchanger, a first decompressor, a first indoor heat exchanger, and a second indoor heat exchanger, and returning to the compressor to perform a cooling operation. Means for passing the refrigerant discharged from the compressor through an outdoor heat exchanger, a first indoor heat exchanger, a second decompressor, and a second indoor heat exchanger to return the compressor to a dry operation; An indoor humidity sensor for detecting indoor humidity, and an indoor humidity sensor for detecting indoor humidity. During a dry operation, a correction amount for the current capacity of the compressor is obtained in accordance with the detected humidity of the indoor humidity sensor, and the capacity is determined by the correction amount. Means for controlling the room temperature during dry operation. Means for determining a correction amount for the current rotational speed of the outdoor fan according to the detected temperature of the outdoor fan, and controlling the rotational speed by the correction amount; and in a dry operation, the correction amount for the rotational speed of the outdoor fan decreases. The air conditioner further comprises means for increasing the operating frequency of the compressor by a predetermined value if the rotation speed of the outdoor fan is at a predetermined minimum value when the rotation speed of the outdoor fan is at a predetermined minimum value.