JPH11101522A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the reliability of a device by lowering the rise of high pressure upon transition such as upon start of heating. SOLUTION: An air conditioner has a refrigerant circuit comprising a compressor 1, a four-way valve 2, an outdoor heat exchanger 3 serving as a condenser upon cooling and as an evaporator upon heating and having an indoor fan 7, an electronic expansion valve 5 and an indoor heat exchanger 6 serving as an evaporator upon cooling and as a condenser upon heating and having an indoor fan 8. In the air conditioner, the four-way valve 2 is switched to reversibly supply the refrigerant in the refrigerant circuit so that a cooling or heating operation can be performed. The air conditioner is provided with a first control means for controlling to increase speed so that the air volume of the indoor fan 8 is raised to that not lower than a prescribed air volume when room air temperature Tr upon start of heating is higher than a prescribed temperature Trs and the air volume of the indoor fan 8 is set to very low value. Thus, the sudden rise of high pressure is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to an air conditioner having a high pressure reduction control function during a heating overload operation.

[0002]

2. Description of the Related Art Generally, during a heating operation of an air conditioner, such as when a temperature set by a remote controller is high,
If the heating overload operation in which the indoor air temperature becomes high is continued, the temperature of the indoor heat exchanger becomes too high, and as a result, the discharge-side refrigerant pressure of the compressor (that is, the high-pressure refrigerant pressure) increases. In order to prevent the high pressure from rising, the air flow of the indoor fan is shifted according to the temperature of the indoor heat exchanger (for example, the air flow is switched from a weak air flow to a strong air flow or from a weak air flow to a weak air flow). I have to.

[0003]

However, in a transient state such as when the heating is started (for example, when the thermostat is turned on or when the defrosting operation is switched to the heating operation, etc.), the time for detecting the temperature of the heat exchanger is reduced. Due to the displacement or the like, the high pressure may increase before the air flow of the indoor fan is shifted, and a problem may occur in that a protection device such as a high pressure switch is activated. In particular, when the air volume of the indoor fan is set to “weak air volume” (hereinafter, referred to as “L”) when heating is started, as shown in FIG. 3, when the indoor intake air temperature is high (for example, 25 ° C. or more). In some cases), the temperature of the indoor heat exchanger may rise rapidly, and the high pressure may rise above the operating pressure (30K) of the protection device before performing the air volume control described above.

[0004] The present invention has been made in view of the above points, and increases the high-pressure pressure during a transition such as when heating is started (for example, when the thermo-ON or defrosting operation is switched to the heating operation). It is an object of the present invention to suppress the above and to secure the reliability of the device.

[0005]

In the basic configuration of the present invention (the first aspect of the present invention), as means for solving the above-mentioned problems, the compressor 1, the four-way switching valve 2, and the function as a condenser during cooling operation. The outdoor heat exchanger 3 having an outdoor fan 7 and an electronic expansion valve 5 provided with an outdoor fan 7 at the time of heating operation, an evaporator at the time of cooling operation and a condenser at the time of heating operation, and an indoor fan 8 provided at the same time. Air having a refrigerant circuit A having an indoor heat exchanger 6 and allowing the refrigerant in the refrigerant circuit A to reversibly circulate by switching the four-way switching valve 2 to perform a cooling operation or a heating operation. In the harmony device, when the indoor air temperature Tr at the time of starting the heating operation is higher than the predetermined temperature Trs and the air volume of the indoor fan 8 is set to a weak air volume, The inner fan 8 is attached a first control means for the speed increasing operation control as air volume above the set air amount is obtained.

With the above configuration, when the indoor air temperature Tr is high and the heating operation is started in a state where the indoor fan 8 is set to a weak air flow, the condensation capacity in the indoor heat exchanger 6 is reduced. May become insufficient and the temperature of the indoor heat exchanger 6 may rise sharply. However, in the present invention, when the indoor air temperature Tr is higher than a predetermined temperature at the time of starting the heating operation, When the air volume is set to a low air volume, the indoor fan 8
Is controlled so as to obtain an air volume equal to or larger than the set air volume, so that the condensing capacity of the indoor heat exchanger 6 is improved. Therefore, the indoor heat exchanger 6
Is suppressed, and the operation of the protection device due to the rapid increase in high pressure can be prevented.

As in the second aspect of the present invention, the first
The speed increase operation of the indoor fan 8 by the control means is performed after a lapse of a predetermined time and the heat exchange temperature Tc of the indoor heat exchanger 6 is changed.
When the temperature is lower than the first set temperature Tcs ₁ , the temperature Tc of the indoor heat exchanger 6 is stabilized by the speed-up operation of the indoor fan 8 after the heating operation is started (in other words, , When the high pressure is stable)
The speed increase operation of the indoor fan 8 is terminated, and the airflow is returned to the set airflow, ie, the weak airflow. Therefore, the operation returns to the heating operation at the set air volume requested by the user, and the sense of discomfort that the air volume is increasing without knowing it is eliminated.

[0008] As in the third aspect of the invention, the first
After the speed increasing operation of the indoor fan 8 by the control means is completed, when the temperature Tc of the indoor heat exchanger 6 has exceeded a higher second predetermined temperature Tcs ₂ than the set temperature Tcs ₁ wherein the first Controls the speed increase operation of the indoor fan 8 so as to obtain an air volume equal to or greater than the set air volume, and the temperature Tc of the indoor heat exchanger 6 is lower than the third set temperature Tcs ₃ lower than the first set temperature Tcs _1. In the case where the second control means for returning the indoor fan 8 to the set air volume is provided when the indoor air temperature Tr is high during the normal operation after the heating operation is started, the indoor fan 8 is accelerated. Although the temperature Tc of the indoor heat exchanger 6 does not rapidly decrease even when the operation is performed, when the temperature Tc of the indoor heat exchanger 6 increases (that is,
A second set temperature T higher than the first set temperature Tcs ₁
When a control of lowering the temperature Tc of the indoor heat exchanger 6 is driving accelerating the indoor fan 8 when exceeded cs _2), the temperature Tc of the indoor heat exchanger 6 is lowered by a predetermined temperature (i.e., the first Third set temperature Tcs ₃ lower than _first set temperature Tcs ₁
(When it becomes less than), the control to return the indoor fan 8 to the set airflow is performed, so that the airflow of the indoor fan 8 can be switched smoothly without hunting.

According to a fourth aspect of the present invention, the indoor-inlet air temperature Tr at the time of starting the heating operation is the predetermined temperature Tr.
s, and when the air volume of the indoor fan 8 is set to a weak air volume, the second set temperature at which the temperature Tc of the indoor heat exchanger 6 is higher than the first set temperature Tcs ₁ When Tcs ₂ is exceeded, the indoor fan 8 is speed-controlled so as to obtain an air volume equal to or greater than the set air volume, and the temperature Tc of the indoor heat exchanger 6 is set to the second set temperature T.
In the case where the third control means for returning the indoor fan 8 to the set air volume is provided when the temperature becomes less than cs _2, and when the indoor air temperature Tr is low at the time of starting the heating operation, the speed of the indoor fan 8 is increased. At least in the indoor heat exchanger 6
Is not rapidly increased, the indoor fan 8 is not accelerated, and the temperature Tc of the indoor heat exchanger 6 is reduced to the second set temperature T.
If the air flow exceeds cs ₂ , the indoor fan 8 is operated at an increased speed so that an air volume equal to or greater than a set air volume is obtained, and the indoor heat exchanger 6 is operated.
And the temperature Tc of the indoor heat exchanger 6.
Although but when it becomes the second set temperature Tcs than ₂ is to perform a control of returning the set air volume of the indoor fan 8, when the room air temperature Tr is low, increasing the indoor fan 8 Since the temperature Tc of the indoor heat exchanger 6 is greatly reduced by the high-speed operation, there is no possibility that the air volume switching of the indoor fan 8 causes hunting, and the operation can be promptly shifted to the operation at the set air volume required by the user.

[0010]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

As shown in FIG. 1, this air conditioner has a compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3 which functions as a condenser during a cooling operation and as an evaporator during a heating operation, and a receiver 4. An electronic expansion valve 5 acting as a pressure reducing mechanism, and a refrigerant circuit A in which an indoor heat exchanger 6 acting as an evaporator during cooling operation and acting as a condenser during heating operation is sequentially connected via a refrigerant pipe. By the switching operation of the four-way switching valve 2, the refrigerant can be reversibly circulated in the direction indicated by the solid arrow during the cooling operation and in the direction indicated by the dotted arrow during the heating operation. Reference numeral 7 denotes an outdoor fan that blows air to the outdoor heat exchanger 3, and 8 denotes an indoor fan that blows air to the indoor heat exchanger 6.

The refrigerant circuit A has four check valves 9A to 9A.
9D, a refrigerant flow control mechanism 9 comprising a receiver 4 and the electronic expansion valve 5 is connected to the liquid refrigerant from the outdoor heat exchanger 3 during cooling operation.
And the refrigerant flow direction is controlled such that the liquid refrigerant from the indoor heat exchanger 6 flows to the outdoor heat exchanger 3 via the receiver 4 and the electronic expansion valve 5 during the heating operation. Has become. The upper part of the receiver 4 and the downstream side of the electronic expansion valve 5 are communicated by a gas vent passage 19 provided with a capillary tube 20. By extracting gas from the receiver 4 through the gas release passage 19, the amount of liquid refrigerant accumulated in the receiver 4 can be maximized.

A low-pressure switch 1 that operates when the suction pressure of the compressor 1 falls below a predetermined value is provided in the refrigerant circuit A.
0, a high pressure switch 11 that operates when the discharge pressure of the compressor 1 becomes equal to or higher than a predetermined value, a discharge pipe temperature sensor 12 that detects the discharge pipe temperature of the compressor 1, and an outside air temperature sensor 13 that detects the outside air temperature. An external heat exchange temperature sensor 14 for detecting the refrigerant temperature of the outdoor heat exchanger 3, an internal heat exchange temperature sensor 15 for detecting the refrigerant temperature Tc of the indoor heat exchanger 6, and a room temperature sensor for detecting the indoor air temperature Tr 16 and a suction pipe temperature sensor 25 for detecting the suction pipe temperature of the compressor 1.

The compressor 1, the four-way switching valve 2, the outdoor heat exchanger 3, the receiver 4, the electronic expansion valve 5, and the outdoor fan 7 constitute an outdoor unit X, and the indoor heat exchanger 6 And the indoor fan 8 is an indoor unit Y
Is to be configured. Reference numeral 17 denotes a liquid-side stop valve,
Reference numeral 18 is a gas side shut-off valve.

Signals from the low pressure switch 10, the high pressure switch 11, the discharge pipe temperature sensor 12, the outside air temperature sensor 13, the outside heat exchange temperature sensor 14, and the suction pipe and the sensor 25 are provided to the outdoor unit X. An outdoor control unit 21 that performs various arithmetic processing by input and outputs control signals to the compressor 1, the four-way switching valve 2, the outdoor fan 7, and the electronic expansion valve 5 is provided. The outdoor control unit 21 receives a signal from a pump down switch 22 that is turned on at the start of the pump down operation.

On the other hand, the indoor unit Y performs various arithmetic processings based on signal inputs from the internal heat exchange temperature sensor 15 and the room temperature sensor 16 and outputs a control signal to the indoor fan 8. Is provided. Note that the indoor control unit 23 exchanges signals with the remote controller 24.

Signals are exchanged between the outdoor control unit 21 and the indoor control unit 23.

The indoor control unit 23 has a function of controlling the compressor 1, the four-way switching valve 2, the electronic expansion valve 5, the outdoor fan 7, and the indoor fan 8 (ie, a normal operation control function). When the indoor air temperature Tr at the time of starting the heating operation is higher than a predetermined temperature Trs (for example, 25 ° C.) and the airflow of the indoor fan 8 is set to a weak airflow, the indoor fan 8 The speed-up operation is controlled so that the air volume equal to or greater than the set air volume is obtained, and the speed-up operation of the indoor fan 8 is performed for a predetermined time t ₁ (for example, 5
Min) after the lapse of the heat exchange temperature Tc of the indoor heat exchanger 6.
A function as a first control means for terminating when the temperature falls below a _first set temperature Tcs ₁ (for example, 55 ° C.),
After the speed increase operation of the indoor fan 8 by the first control means is completed, the temperature Tc of the indoor heat exchanger 6 is changed.
Exceeds a _second set temperature Tcs ₂ (for example, 60 ° C.) higher than the first set temperature Tcs _{1, the} indoor fan 8 is controlled to perform a speed-up operation so that an air volume equal to or greater than the set air volume is obtained. And the temperature Tc of the indoor heat exchanger 6 is equal to the first temperature.
If the temperature is lower than a third set temperature Tcs ₃ (for example, 50 ° C.) lower than the set temperature Tcs _{1, the} indoor fan 8
As the second control means for returning the set air volume to the set air volume, and the air volume of the indoor fan 8 is set to the weak air volume when the indoor air temperature Tr at the time of starting the heating operation is lower than the predetermined temperature Trs. In such a case, the indoor heat exchanger 6
When the temperature Tc of the indoor heat exchanger 6 exceeds the _second set temperature Tcs2, the indoor fan 8 is controlled to perform the speed-up operation so as to obtain an air flow larger than the set air flow, and the temperature T of the indoor heat exchanger 6 is controlled.
When c becomes lower than the second set temperature Tcs ₂ , it has a function as third control means for returning the indoor fan 8 to the set air volume.

Next, with reference to a flowchart shown in FIG. 2, a description will be given of the high-pressure reduction control during the heating overload operation in the air conditioner according to the present embodiment.

When it is confirmed in step S ₁ that the heating operation has started (that is, the thermo-ON, the heating operation has started after the defrosting operation has been completed, etc.), in step S ₂ , the room temperature sensor 16 and the internal heat exchange temperature sensor 15 output the signals. Temperature information (that is, indoor air temperature Tr and indoor heat exchange temperature Tc) is input.

[0021] Then, the room air temperature Tr and the predetermined temperature Trs (for example, 25 ° C.) in step S ₃ are made compared with, wherein when it is determined that Tr ≧ 25 ° C. (i.e.,
In the case where the indoor air temperature Tr is determined to be higher overloaded), the process proceeds to step S _4, the set air volume is weak air volume by the user (i.e., the determination of whether the air volume "L") is made You. Here, when a negative determination is made (that is, when it is determined that the set air volume = strong: “H”), there is no shortage of the condensation capacity in the indoor heat exchanger 6 and there is no possibility that the high pressure will rise rapidly. returns to step S ₁ is omitted subsequent control.

[0022] If an affirmative determination is made in step S _4, condensation capacity is insufficient in the indoor heat exchanger 6, there is a possibility that the high pressure rises rapidly, the indoor fan 8 in step S ₅ is, M taps from the L taps (That is, speed-up operation is performed). Here, the M tap is a tap that cannot be selected by the user's remote control setting, and is a tap that is selected only by a command from the indoor control unit 23.

[0023] By the speed-up operation of the indoor fan 8 described above,
The condensation capacity of the indoor heat exchanger 6 increases, and the temperature T
c come impaired, the predetermined time in step S ₆ t ₁
Until it is determined that (for example, 5 minutes) has elapsed, the speed increasing operation of the indoor fan 8 is continued.

[0024] The bulking speed operation, reduces the temperature Tc of the indoor heat exchanger 6, set in step S ₇ temperature Tc of the indoor heat exchanger 6 is the first temperature Tcs ₁ (e.g., 55 ° C.)
If it is determined that dropped below, because in a state in which high pressure is stable, the indoor fan 8 in step S ₈
Is returned to the L tap (that is, returned to the set airflow, ie, the weak airflow). Incidentally, Tc ≧ Tc in step S ₇
If it is determined that s ₁ (i.e., if even after a predetermined time t ₁ continues the speed increasing operation does not decrease the temperature Tc of the indoor heat exchanger 6 is less), the process proceeds to step S _10, the indoor fan 8 M It is driven with the tap.

By doing so, the indoor air temperature Tr becomes 2
When the heating operation is started in a state higher than 5 ° C. (that is, in a heating overload state), if the indoor fan 8 is set to a small air flow, the condensation capacity in the indoor heat exchanger 6 becomes insufficient. Although the temperature of the indoor heat exchanger 6 may rise sharply, in the present embodiment, as described above,
When the indoor air temperature Tr is higher than 25 ° C. when the heating operation is started and the airflow of the indoor fan 8 is set to a low airflow, the indoor fan 8 can obtain an airflow that is equal to or more than the set airflow. Since the speed-up operation is controlled as described above, the condensing capacity in the indoor heat exchanger 6 is improved. Therefore, the rapid rise of the temperature Tc of the indoor heat exchanger 6 is suppressed, and the operation of the protection device due to the rapid rise of the high pressure can be prevented.

When the temperature Tc of the indoor heat exchanger 6 becomes stable (in other words, a state in which the high pressure is stabilized) by the speed-up operation of the indoor fan 8, the speed-up operation of the indoor fan 8 is terminated. Therefore, since the air flow is to be returned to the set air flow, which is a weak air flow, the operation returns to the heating operation at the set air flow which is the user's request, and the uncomfortable feeling that the air flow is increasing without knowing is also eliminated. .

[0027] after the speed increasing operation of the indoor fan 8 as described above is completed also, monitoring of the temperature Tc of the indoor heat exchanger 6 is continued, the temperature T of the indoor heat exchanger 6 in step S ₉
wherein the c first set temperature Tcs higher than ₁ second set temperature Tcs ₂ (e.g., 60 ° C.) made a comparison between, when the decision is Tc> 60 ° C. and an indoor fan 8 at step S ₁₀ Is switched from the L tap to the M tap (that is, speed-up operation is performed). Since the temperature Tc of the indoor heat exchanger 6 decreases due to the speed-up operation, step S
_{At 11} , the temperature Tc of the indoor heat exchanger 6 and a third set temperature Tcs ₃ lower than the first set temperature Tcs ₁ (for example,
50 ° C.), and the speed-up operation is continued until it is determined that Tc <50 ° C. Step S ₁₁
If it is determined that Tc <50 ° C. in, the process returns to step S _8, the indoor fan 8 is returned from the M taps L taps (i.e., returned to the weak wind quantity is set air volume), hereinafter the same control line Will be

In this manner, when the indoor air temperature Tr is high during normal operation after the heating operation is started (ie, in the case of a heating overload state), the indoor heat exchange is performed even if the indoor fan 8 is accelerated. Although the temperature Tc of the heat exchanger 6 does not decrease quickly, when the temperature Tc of the indoor heat exchanger 6 rises (that is, when the temperature exceeds 60 ° C.), the speed of the indoor fan 8 is increased and the indoor heat exchanger is operated. 6 when the temperature Tc of the indoor heat exchanger 6 has decreased by a predetermined temperature (that is, when the temperature Tc of the indoor heat exchanger 6 has decreased by a predetermined temperature).
(When the temperature is lower than 50 ° C.), the control to return the indoor fan 8 to the set air volume is performed, so that the set temperature difference at the time of air volume switching becomes large, and the air volume switching of the indoor fan 8 causes hunting. It can be done smoothly without.

[0029] If it is determined that Tr <25 ° C. in step S ₃ (ie, heating when it is determined not to be overloaded), the process proceeds to step S _12, the set air volume is weak air volume by the user (i.e., It is determined whether or not the air volume is “L”). Here, if a negative determination (i.e., the set air volume = Strength: If it is determined as "H"), the process returns to step S ₁ is omitted subsequent control. Note that, in this case, since the heating is not in the overload state, a rapid rise in high pressure does not occur. Therefore, the speed increasing operation of the indoor fan 8 at the time of the heating start described above is not performed.

[0030] When a positive determination is made in step S _12, the predetermined time in step S ₁₃ (e.g., 2 minutes)
After but confirmed to have elapsed, monitors the temperature Tc of the indoor heat exchanger 6 in step S _14, the temperature Tc and the second set temperature Tc of the indoor heat exchanger 6 in step S ₁₄
s ₂ (eg, 60 ° C.) where Tc
> If it is determined that 60 ° C., the indoor fan 8 at step S ₁₅ is switched from the L taps M taps (i.e., are operated accelerated). Incidentally, T in step S ₁₄
If it is determined that c ≦ 60 ° C., the process returns to step S _13, waits for a lapse of a predetermined time t _2.

[0031] Since the temperature Tc of the indoor heat exchanger 6 by the speed increasing operation is lowered, in step S ₁₆ a predetermined time (e.g., 2 minutes) after it is confirmed that has passed, the indoor heat in step S ₁₇ A temperature lower by 1 ° C. than the temperature Tc of the exchanger 6 and the second set temperature Tcs ₂ (for example, 59
C), and the speed-up operation is continued until it is determined that Tc <59 ° C. If in step S ₁₇ it is determined that Tc <59 ° C., the process proceeds to step S _18, the indoor fan 8 is returned from the M taps L taps (i.e., returned to the weak wind quantity is set air volume), a subsequent similar Control is performed. If it is determined that Tc ≧ 59 ° C. In step S _17, the process returns to step S _15, waits for a lapse of a predetermined time t ₂ while continuing the accelerating operation of the indoor fan 8.
The temperature Tc of the indoor heat exchanger 6 in step S ₁₇
Is compared to a second set temperature Tcs ₂ (for example, 6
0 ° C.).

In this way, when the indoor air temperature Tr is low at the time of starting the heating operation (that is, when the indoor air temperature is less than 25 ° C.), the indoor fan 8 can be placed in the indoor heat exchanger 6 without increasing the speed. Since Tc does not rise sharply, the indoor fan 8 is not accelerated and the temperature Tc of the indoor heat exchanger 6 is not increased.
When the temperature exceeds 60 ° C., the indoor fan 8 is controlled to reduce the temperature Tc of the indoor heat exchanger 6 by increasing the speed of the indoor fan 8 so that the air volume is equal to or greater than the set air volume.
When c is less than 59 ° C., control is performed to return the indoor fan 8 to the set air volume. as a result,
When the indoor air temperature Tr is low, the temperature Tc of the indoor heat exchanger 6 is greatly reduced by the speed-up operation of the indoor fan 8, so that even if the set temperature difference at the time of air volume switching is almost eliminated,
There is no danger of hunting being caused by switching the air flow of the indoor fan 8, and the operation can be promptly shifted to the operation at the set air flow requested by the user.

[0033]

According to the invention of the present application (the invention of claim 1),
A compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3 having an outdoor fan 7 and an electronic expansion valve 5, which functions as a condenser during a cooling operation and as an evaporator during a heating operation, and as an evaporator during a cooling operation. It has a refrigerant circuit A having an indoor heat exchanger 6 provided with an indoor fan 8 and acting as a condenser during a heating operation, and switching the four-way switching valve 2 to operate the refrigerant in the refrigerant circuit A. In which the indoor air temperature Tr at the time of starting the heating operation is higher than the predetermined temperature Trs, and the air volume of the indoor fan 8 becomes a weak air volume. If it is set, a first control means for controlling the indoor fan 8 to perform a speed-up operation so as to obtain an air volume equal to or higher than the set air volume is provided, and the heating operation is started. In the case where the indoor air temperature Tr is higher than the predetermined temperature and the air volume of the indoor fan 8 is set to a low air volume, the indoor fan 8 is accelerated so that the air volume equal to or higher than the set air volume is obtained. Since the operation control is performed, if the indoor fan 8 is set to a weak air flow when the heating operation is started in a state where the indoor air temperature Tr is high, the condensation capacity in the indoor heat exchanger 6 is insufficient. As a result, the temperature of the indoor heat exchanger 6 may rise sharply, but the speed-up operation of the indoor fan 8 improves the condensation capacity of the indoor heat exchanger 6 and the indoor heat exchanger 6
Is suppressed, and there is an excellent effect that the protection device can be prevented from operating due to the rapid increase in high pressure.

As in the second aspect of the present invention, the first
If the speed increasing operation of the indoor fan 8 by the control means, the temperature Tc of the indoor heat exchanger 6 even after the predetermined time has elapsed is to be terminated at the time when a first predetermined temperature Tcs than ₁ When the temperature Tc of the indoor heat exchanger 6 becomes stable (in other words, a state where the high pressure is stabilized) by the speed-up operation of the indoor fan 8 after the heating operation is started, the speed-up operation of the indoor fan 8 is terminated. As a result, the set airflow is returned to the weak airflow. Therefore, the operation returns to the heating operation at the set air volume requested by the user, and the sense of discomfort that the air volume is increasing without knowing it is eliminated.

As in the third aspect of the present invention, the first
After the speed increasing operation of the indoor fan 8 by the control means is completed, when the temperature Tc of the indoor heat exchanger 6 has exceeded a higher second predetermined temperature Tcs ₂ than the set temperature Tcs ₁ wherein the first Controls the speed increase operation of the indoor fan 8 so as to obtain an air volume equal to or greater than the set air volume, and the temperature Tc of the indoor heat exchanger 6 is lower than the third set temperature Tcs ₃ lower than the first set temperature Tcs _1. In the case where the second control means for returning the indoor fan 8 to the set air volume is provided when the indoor air temperature Tr is high during the normal operation after the heating operation is started, the indoor fan 8 is accelerated. Although the temperature Tc of the indoor heat exchanger 6 does not rapidly decrease even when the operation is performed, when the temperature Tc of the indoor heat exchanger 6 increases (that is,
A second set temperature T higher than the first set temperature Tcs ₁
When a control of lowering the temperature Tc of the indoor heat exchanger 6 is driving accelerating the indoor fan 8 when exceeded cs _2), the temperature Tc of the indoor heat exchanger 6 is lowered by a predetermined temperature (i.e., the first Third set temperature Tcs ₃ lower than _first set temperature Tcs ₁
(When it becomes less than), the control to return the indoor fan 8 to the set airflow is performed, so that the airflow of the indoor fan 8 can be switched smoothly without hunting.

According to the fourth aspect of the present invention, the indoor air temperature Tr at the time of starting the heating operation is equal to the predetermined temperature Tr.
s, and when the air volume of the indoor fan 8 is set to a weak air volume, the second set temperature at which the temperature Tc of the indoor heat exchanger 6 is higher than the first set temperature Tcs ₁ When Tcs ₂ is exceeded, the indoor fan 8 is speed-controlled so as to obtain an air volume equal to or greater than the set air volume, and the temperature Tc of the indoor heat exchanger 6 is set to the second set temperature T.
In the case where the third control means for returning the indoor fan 8 to the set air volume is provided when the temperature becomes less than cs _2, and when the indoor air temperature Tr is low at the time of starting the heating operation, the speed of the indoor fan 8 is increased. At least in the indoor heat exchanger 6
Is not rapidly increased, the indoor fan 8 is not accelerated, and the temperature Tc of the indoor heat exchanger 6 is reduced to the second set temperature T.
If the air flow exceeds cs ₂ , the indoor fan 8 is operated at an increased speed so that an air volume equal to or greater than a set air volume is obtained, and the indoor heat exchanger 6 is operated.
And the temperature Tc of the indoor heat exchanger 6.
Although but when it becomes the second set temperature Tcs than ₂ is to perform a control of returning the set air volume of the indoor fan 8, when the room air temperature Tr is low, increasing the indoor fan 8 Since the temperature Tc of the indoor heat exchanger 6 is greatly reduced by the high-speed operation, there is no possibility that the air volume switching of the indoor fan 8 causes hunting, and the operation can be promptly shifted to the operation at the set air volume required by the user.

[Brief description of the drawings]

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

FIG. 2 is a flowchart illustrating high-pressure reduction control when the air conditioner according to the embodiment of the present invention is overloaded with heating.

FIG. 3 is a characteristic diagram showing behaviors of an indoor air temperature, an indoor heat exchanger temperature, and a high pressure when starting heating in a conventional air conditioner.

[Explanation of symbols]

1 is a compressor, 2 is a four-way switching valve, 3 is an outdoor heat exchanger, 5 is a pressure reducing mechanism (electronic expansion valve), 6 is an indoor heat exchanger, 7 is an outdoor fan, 8 is an indoor fan, and 15 is internal heat. Interchange temperature sensor,
16 is a room temperature sensor, 21 is an outdoor control unit, 23 is an indoor control unit, A is a refrigerant circuit, X is an outdoor unit,
Y is the indoor unit, Tc is the indoor heat exchanger temperature, Tcs ₁
Is the first set temperature, Tcs ₂ is the second set temperature, Tcs ₃
Is a third set temperature, Tr is a room air temperature, and Trs is a predetermined temperature.

Claims (4)

[Claims] An outdoor heat exchanger (3) provided with a compressor (1), a four-way switching valve (2), a condenser during a cooling operation, an evaporator during a heating operation, and an outdoor fan (7). ), An electronic expansion valve (5), a refrigerant circuit (A) having an indoor heat exchanger (6) having an indoor fan (8) and acting as a condenser during a cooling operation and acting as a condenser during a heating operation. An air conditioner having a cooling operation or a heating operation by reversibly circulating the refrigerant in the refrigerant circuit (A) by switching the four-way switching valve (2) to perform a cooling operation or a heating operation. When the indoor air temperature (Tr) at the time of startup is higher than the predetermined temperature (Trs) and the airflow of the indoor fan (8) is set to a low airflow, the indoor fan (8) is set to the above-mentioned setting. The air volume more than the air volume An air conditioner, further comprising first control means for performing speed-up operation control so as to be obtained. 2. The method according to claim 1, wherein the step of increasing the speed of the indoor fan by the first control means is performed after a lapse of a predetermined time, and the temperature (Tc) of the indoor heat exchanger is set to a first set temperature. (T
2. The air conditioner according to claim 1, wherein the air conditioner is terminated at a time when cs ₁ ) is less than cs ₁ ). 3. The temperature (Tc) of the indoor heat exchanger (6) is changed to the first preset temperature (Tc) after the speed increase operation of the indoor fan (8) by the first control means is completed.
When the temperature exceeds the _second set temperature (Tcs ₂ ) higher than cs ₁ ), the indoor fan (8) is controlled to perform the speed-up operation so that the air volume equal to or larger than the set air volume is obtained, and the indoor heat exchanger (6) is controlled. ) Is the first set temperature (Tc).
s ₁₎ lower than the third set temperature (in the case of a Tcs ₃₎ less than the claim 2, wherein the annexed a second control means for returning the set air volume of the indoor fan (8) Air conditioner. 4. When the indoor air temperature (Tr) at the time of starting the heating operation is lower than the predetermined temperature (Trs) and the air flow of the indoor fan (8) is set to a weak air flow, The heat exchange temperature of the indoor heat exchanger (6) (T
If c) exceeds a _second set temperature (Tcs ₂ ) higher than the first set temperature (Tcs ₁ ), the indoor fan (8) is accelerated so that an air flow larger than the set air flow is obtained. Third control means for controlling and returning the indoor fan (8) to the set airflow when the temperature (Tc) of the indoor heat exchanger (6) becomes lower than the second set temperature (Tcs ₂ ). 2. The method according to claim 1, further comprising:
An air conditioner according to any one of the preceding claims.