JP2842020B2 - Operation control device for 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 operation control device for an air conditioner, and more particularly to a measure for controlling the capacity of a compressor.

[0002]

2. Description of the Related Art Conventionally, air conditioners have been disclosed in
As disclosed in JP-147270A, a compressor whose capacity is controlled by an inverter, a four-way switching valve, an outdoor heat exchanger, an electric expansion valve, and an indoor heat exchanger are connected in order, In some cases, the operating frequency of the inverter is controlled based on the evaporation temperature of the compressor to increase or decrease the capacity of the compressor.

Further, the air conditioner detects a condensing pressure equivalent saturation temperature, for example, detects a condensing temperature of an outdoor heat exchanger during a cooling cycle, and when the condensing temperature rises, a predetermined temperature is reached. In some cases, the operating frequency of the inverter is reduced by a predetermined amount to reduce the compressor capacity, thereby suppressing an increase in the high-pressure refrigerant pressure.

[0004]

In the above-described air conditioner, when the high pressure rises, only one predetermined temperature is set to lower the compressor capacity.
At the time of starting or the like, there is a problem that the high-pressure refrigerant pressure on the discharge side of the compressor rises to an abnormal pressure value and the high-pressure switch is activated.

That is, the condensing temperature may suddenly increase in an overload state such as at the time of starting. In this case, even if the compressor capacity is reduced while the condensing temperature exceeds a predetermined temperature,
There is a problem that the droop of the operating frequency cannot catch up, the high-pressure refrigerant pressure overshoots the abnormal pressure value and the high-pressure pressure switch is activated, and the air-conditioning operation is stopped.

The present invention has been made in view of the above points, and is intended to surely suppress the increase in the pressure of the high-pressure refrigerant even when the saturation temperature corresponding to the condensing pressure suddenly rises during an overload or the like. .

[0007]

Means for Solving the Problems In order to achieve the above-mentioned object, a measure taken by the present invention is to judge a sudden rise in the saturation temperature corresponding to the condensing pressure and to increase the decrease in the compressor capacity during the sudden rise. It was done.

More specifically, as shown in FIG. 1, means taken by the invention according to claim 1 firstly includes a variable capacity compressor (1).
, A heat source side heat exchanger (3), an expansion mechanism (5), and a use side heat exchanger (6) are sequentially connected to an air conditioner provided with a refrigerant circuit (9).

A saturation temperature detecting means (Thc, The) for detecting a saturation temperature corresponding to the condensing pressure in the refrigerant circuit (9).
When the saturation temperature corresponding to the condensation pressure detected by the saturation temperature detecting means (Thc, The) rises to the first set temperature, the compressor (1)
To reduce the capacity of the first by a first predetermined amount set in advance.
Capacity reduction means (11) is provided. Further, when the condensation temperature equivalent saturation temperature detected by the saturation temperature detection means (Thc, The) rises to a second set temperature lower than the first set temperature, a rate of increase of the condensation pressure equivalent saturation temperature is determined. If the rate of increase is equal to or higher than a predetermined value, a rate-of-increase determining means (12) for outputting a sudden increase signal is provided. In addition, when the rate-of-increase determination means (12) outputs a sudden rise signal, the second capacity reduction means (14) for reducing the capacity of the compressor (1) by a second predetermined amount larger than the first predetermined amount is provided. The configuration is provided.

The means according to the second aspect of the present invention is different from the first aspect of the invention in that the cooling rate detected by the saturation temperature detecting means (Thc, The) is replaced with the rising rate determining means (12). When the condensing pressure equivalent saturation temperature rises to the second set temperature lower than the first set temperature, the rise rate of the condensing pressure equivalent saturation temperature is determined, and if the rise rate is equal to or more than a predetermined value, a sudden rise signal is generated. Output first climb rate determination means (12)
A rate of increase in the condensing pressure equivalent saturation temperature when the condensing pressure equivalent saturation temperature during the heating cycle detected by the saturation temperature detecting means (Thc, The) rises to a third set temperature lower than the second set temperature. And if the rate of increase is equal to or greater than a predetermined value, a second rate-of-increase determining means (13) for outputting a sudden increase signal
Are provided. When the first rate-of-increase determining means (12) or the second rate-of-incidence determining means (13) outputs a steep rise signal, the second capacity reducing means (14) outputs the compressor.
The capacity of (1) is reduced by a second predetermined amount larger than the first predetermined amount.

[0011]

According to the first aspect of the present invention,
First, in the refrigerant circuit (9), for example, the liquid refrigerant condensed and liquefied in the heat source side heat exchanger (3) is decompressed by the expansion mechanism (5), and then evaporated in the use side heat exchanger (6). And return to the compressor (1).

During the air-conditioning operation, the saturation temperature detecting means (Thc, The) detects the saturation temperature corresponding to the condensing pressure,
For example, during the cooling cycle, the heat source side heat exchanger (3)
The external heat exchange temperature Tc from the external heat exchange sensor (Thc) provided in the controller is read.

Thereafter, the rise rate determining means (12) determines whether the external heat exchange temperature Tc, which is the saturation temperature corresponding to the condensing pressure, has exceeded a second predetermined temperature, for example, 56 ° C., and determines the temperature rise rate. Then, for example, it is determined whether the temperature has risen by 2 ° C. or more in 15 seconds. And whether the external heat exchange temperature Tc is 56 ° C. or less,
Alternatively, if the temperature does not increase by 2 ° C. or more in 15 seconds even when the temperature exceeds 56 ° C., the first capacity lowering means (11) sets the external heat exchange temperature Tc
When the temperature exceeds a first predetermined temperature, for example, 62 ° C., the capacity of the compressor (1) is reduced by a first predetermined amount.

On the other hand, when the rise rate determining means (12) determines that the external heat exchange temperature Tc has exceeded 56 ° C. and has risen by 2 ° C. or more in 15 seconds, it outputs a rapid rise signal, and the second capacity lowering means. (14) increases the capacity of the compressor (1) to the second
Reduce by a predetermined amount. As a result, when the external heat exchange temperature Tc rises rapidly, the capacity of the compressor (1) is greatly reduced.

According to the second aspect of the present invention, during the cooling cycle, the rate-of-increase determining means (12) according to the first aspect of the present invention becomes the first rate-of-increase determining means (12). Control the capacity of (1).

On the other hand, during the heating cycle, the second rate-of-increase determining means (13) detects the saturation temperature corresponding to the condensing pressure detected by the internal heat exchange sensor (The) provided in the use side heat exchanger (6). It is determined whether the internal heat exchange temperature Te has exceeded a third set temperature, for example, 54 ° C., and the rate of temperature rise is determined, for example,
It is determined whether the temperature has risen by 2 ° C. or more in 15 seconds. And the above internal heat exchange temperature Te is 54 ° C or less, or 54 ° C
If the temperature does not rise by more than 2 ° C. in 15 seconds even after exceeding the temperature, the first capacity reducing means (11) controls the compressor (1) as described above.
Will be controlled.

When the second rate-of-increase determining means (13) determines that the internal heat exchange temperature Te has exceeded 54 ° C. and has increased by 2 ° C. or more in 15 seconds, it outputs a rapid rise signal and outputs the second capacity. The reduction means (14) reduces the capacity of the compressor (1) by a second predetermined amount.

[0018]

Therefore, according to the first aspect of the present invention,
When the rise rate of the saturation temperature equivalent to the condensing pressure is large, the compressor
Since the reduced capacity of (1) is increased, it is possible to reliably suppress an increase in the high-pressure refrigerant pressure in an overload state such as at startup. As a result, the operation of the high pressure switch can be suppressed, so that the air conditioning operation can be continued and the comfort can be improved.

According to the second aspect of the present invention, the capacity of the compressor (1) is reduced in a state where the saturation temperature corresponding to the condensing pressure is lower in the heating cycle than in the cooling cycle. Even in a state where the responsiveness is poor, an increase in the high-pressure refrigerant pressure can be reliably suppressed, and the operation of the high-pressure pressure switch can be suppressed, so that comfort can be improved.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 shows a refrigerant piping system of an air conditioner to which the present invention is applied, which is a so-called separate type in which one outdoor unit (A) is connected to one indoor unit (B). It is.

The outdoor unit (A) includes a scroll type compressor (1) whose operating frequency is variably adjusted by an inverter, and a cutoff as shown by a solid line in the cooling operation and a broken line in the heating operation. Replacement four-way switching valve (2)
And an outdoor heat exchanger that is a heat source side heat exchanger that functions as a condenser during cooling operation and as an evaporator during heating operation.
(3), a decompression unit (20) for decompressing the refrigerant, and a compressor
An accumulator (7) interposed in the suction pipe of (1) for removing the liquid refrigerant in the suction refrigerant is disposed as main equipment. The indoor unit (B) is provided with an indoor heat exchanger (6), which is a use-side heat exchanger that functions as an evaporator during a cooling operation and as a condenser during a heating operation. The compressor (1), the four-way switching valve (2), the outdoor heat exchanger (3), the pressure reducing section (20), the indoor heat exchanger (6), and the accumulator (7) are connected to a pipe ( 8) connected by
A refrigerant circuit (9) is configured to generate heat transfer by circulation of the refrigerant.

Here, the pressure reducing section (20) includes a bridge-shaped rectifier circuit (8a) and a pair of connection points in the rectifier circuit (8a).
(P, Q) connected to a common path (8a), said common path (8a)
There is a receiver (4) for storing the liquid refrigerant, an auxiliary heat exchanger (3a) for the outdoor heat exchanger (3), and an electric expansion which is an expansion mechanism having a function of reducing the pressure of the liquid refrigerant and a function of adjusting the flow rate. Valve (5)
And are arranged in series. And the rectifier circuit (8a)
The other pair of connection points (R, S) in
The pipe (8) on the (3) side and the pipe (8) on the indoor heat exchanger (6) side are connected. Further, the rectifier circuit (8a) connects the upstream connection point (P) of the common path (8a) and the connection point (S) on the outdoor heat exchanger (3) side, and connects the rectifier circuit (8a) from the outdoor heat exchanger (3). Indoor heat exchange between a first inflow path (8b1) having a first check valve (D1) allowing only refrigerant flow to the receiver (4) and an upstream connection point (P) of the common path (8a); Indoor heat exchanger (6) by connecting to the connection point (R) on the side of the heat exchanger (6)
A second inflow path (8b2) provided with a second check valve (D2) that allows only refrigerant flow from the receiver to the receiver (4); a downstream connection point (Q) of the common path (8a); A first check valve (D3) having a third check valve (D3) connecting the connection point (R) on the side of the exchanger (6) and allowing only refrigerant to flow from the electric expansion valve (5) to the indoor heat exchanger (6); Outflow channel (8
c1), the downstream connection point (Q) of the common path (8a) and the connection point (S) on the outdoor heat exchanger (3) side, and the electric expansion valve (5) is connected to the outdoor heat exchanger (3 And a second outflow path (8c2) provided with a fourth check valve (D4) that allows only the flow of the refrigerant to (c).

The common path (8) in the rectifier circuit (8a)
a) Capillary tube (C) between both connection points (P, Q)
A liquid ring prevention bypass path (8f) is provided,
The liquid ring prevention bypass path (8f) prevents liquid ringing when the compressor (1) is stopped, while opening and closing the upper part of the receiver (4) and the downstream side of the common path (8a). A gas vent path (4a) provided with a valve (SV) is connected. The degree of pressure reduction of the capillary tube (C) is set to be sufficiently larger than that of the electric expansion valve (5), so that the refrigerant flow control function of the electric expansion valve (5) during normal operation is maintained well. It has been made possible.

Further, (F1 to F4) are filters for removing dust in the refrigerant, and (ER) is a silencer for reducing the operation noise of the compressor (1).

Further, sensors are provided in the air conditioner, and (Thd) is a discharge pipe sensor that is disposed on the discharge pipe of the compressor (1) to detect the discharge pipe temperature Td, (Tha) Is
An outdoor suction sensor that is disposed at the air suction port of the outdoor unit (A) and detects the suction air temperature Ta, which is the outside air temperature, (Thc)
Is disposed in the outdoor heat exchanger (3), and detects an external heat exchange temperature Tc which is a condensing temperature corresponding to a condensing pressure during a cooling operation and is an evaporating temperature during a heating operation (saturation temperature). Detection means), (Thr) is the indoor unit (B)
Suction air temperature, which is located at the air suction port and is the room temperature
An indoor suction sensor that detects Tr, (The) is an indoor heat exchanger
(6), an internal heat exchange sensor (saturation temperature detecting means) for detecting an internal heat exchange temperature Te which becomes an evaporation temperature during a cooling operation and becomes a condensing temperature which is a saturation temperature corresponding to a condensing pressure during a heating operation, ) Is a high-pressure pressure switch which is a high-pressure detection means that detects a high-pressure refrigerant pressure and turns on due to an excessive rise of the high-pressure refrigerant pressure and outputs a high-pressure signal. (LPS) detects a low-pressure refrigerant pressure. This is a low-pressure switch that is turned on when a low-pressure refrigerant pressure is excessively low to output a low-pressure signal.

The output signals of the sensors (Thd,..., The) and the switches (HPS, LPS) are sent to the controller (10).
The controller (10) is configured to control the air-conditioning operation based on the input signal.

In the above-described refrigerant circuit (9), during cooling operation, liquid refrigerant condensed and liquefied in the outdoor heat exchanger (3) flows in from the first inflow passage (8b1), and flows through the first check valve (D1). ), Is stored in the receiver (4), is decompressed by the electric expansion valve (5), and then evaporates in the indoor heat exchanger (6) through the first outflow passage (8c1) and returns to the compressor (1). On the other hand, during heating operation,
The liquid refrigerant condensed and liquefied in the indoor heat exchanger (6) flows in from the second inflow path (8b2) and passes through the second check valve (D2) to the receiver.
After being stored in (4) and depressurized by the electric expansion valve (5),
After evaporating in the outdoor heat exchanger (3) via the outflow channel (8c2), the compressor
The cycle returns to (1).

On the other hand, as a feature of the present invention, the controller (10) includes a first capacity reduction means (11) and a first rate-of-increase determination means () for controlling the capacity of the compressor (1) to decrease. 12)
And a second rate-of-increase determining means (13) and a second capacity decreasing means (14)
Are provided.

In the compressor (1), the operating frequency of the inverter is divided into 20 steps N from zero to the maximum frequency, and each step N is set based on the discharge pipe temperature Td. It is configured to control the capacity of

On the other hand, the first capacity lowering means (11) is adapted to detect the external heat exchange temperature Tc and the internal heat exchange temperature Te which are the condensation temperatures detected by the external heat exchange sensor (Thc) and the internal heat exchange sensor (The). When the temperature rises to the first set temperature, specifically, it rises to 62 ° C. for the cooling cycle, and 56 ° C. and 5 ° C. for the heating cycle.
When the temperature rises to 7.5 ° C., the capacity of each of the compressors (1) is reduced by a first predetermined amount, that is, the operating frequency by one step N.

The first capacity lowering means (11) sets the external heat exchange temperature Tc, which is the condensation temperature during the cooling cycle detected by the external heat exchange sensor (Thc), to a second set temperature lower than the first set temperature. When the temperature rises, specifically, when the temperature rises from 56 ° C. in the cooling cycle, the rate of increase in the external heat exchange temperature Tc is determined. When the rate of rise is equal to or higher than a predetermined value, that is, 2 ° C. in 15 seconds, a sudden rise signal Is configured to be output.

The second capacity lowering means (14) sets the internal heat exchange temperature Te, which is the condensing temperature during the heating cycle detected by the internal heat exchange sensor (The), to a third set temperature lower than the second set temperature. When the temperature rises, specifically, when the temperature rises from 54 ° C. in the heating cycle, the rate of increase in the internal heat exchange temperature Te is determined. When the rate of rise is equal to or higher than a predetermined value, that is, 2 ° C. in 15 seconds, a sudden rise signal Is configured to be output. The reason why the set temperature during the heating cycle was set lower than during the cooling cycle is that the pipe length from the compressor (1) to the indoor heat exchanger (6) is longer than the pipe length from the outdoor heat exchanger (3). This is because the response is poor.

When the first rate-of-increase determining means (12) or the second rate-of-incidence determining means (13) outputs a sudden increase signal, the second capacity reducing means (14) reduces the capacity of the compressor (1). The capacity is reduced by a second predetermined amount larger than the first predetermined amount, that is, by two steps N.

Next, the capacity control operation of the compressor (1) will be described with reference to the control flow of FIG.

First, in the air-conditioning operation during the cooling cycle, first, in step ST1, it is determined whether or not the sampling timer T has exceeded 5 seconds or is 0 seconds, that is, sampling is performed every 5 seconds. It is determined whether or not the time has elapsed. Until the sampling time, the process proceeds from step ST1 to step ST2, where the non-change area of the compressor (1) is released, and the capacity of the compressor (1) can be changed. And return. When the sampling time comes, the process proceeds from step ST1 to step ST3 to read the external heat exchange temperature Tc from the external heat exchange sensor (Thc) and set the sampling timer T to zero.

After that, the steps ST3 to ST
The first rise rate determination means (12) determines whether or not the external heat exchange temperature Tc, which is the condensing temperature, has exceeded 56 ° C. It is determined whether or not the temperature difference from the intersection temperature Tc is 2 ° C. or more. That is, since the sampling time is 5 seconds, it is determined whether or not the temperature has increased by 2 ° C. or more in 15 seconds. And the above external heat exchange temperature Tc
Is 56 ° C or less, or exceeds 56 ° C for 2 seconds in 15 seconds.
If the temperature has not risen by more than ° C., the determination in step ST4 is NO, and the routine proceeds to step ST2, where normal capacity control is performed. Specifically, the capacity step N of the compressor (1) is set based on the discharge pipe temperature Td,
The capacity reducing means (11) reduces the capacity of the compressor (1) by one step N when the external heat exchange temperature Tc exceeds 62 ° C.

On the other hand, in the above-mentioned step ST4, the first heat-up rate determining means (12) determines that the external heat exchange temperature Tc, which is the condensation temperature, is 56.
If the temperature is determined to exceed 2 ° C. and increase by 2 ° C. or more in 15 seconds, a rapid rise signal is output, and the determination in step ST4 is YES.
Then, the process proceeds to step ST5. The step
In ST5, it is determined whether or not the capacity step N of the compressor (1) is 4 or more. If the capacity is 4 or more, the process proceeds from step ST5 to step ST6, and the step change amount dN is set to -2. I do. That is, the first rising rate determination means (12)
The second capacity reduction means (14) is set to reduce the capacity of the compressor (1) by two steps N based on the judgment of (1).

Subsequently, the operation proceeds to step ST7, where the sampling timer T is started, and thereafter, the operation proceeds to step ST8, where it is determined whether or not the capacity step N of the compressor (1) is 2; When step N is 0, the operating frequency is 0, and the compressor (1) is stopped. When the capacity step N is 2, the capacity of the compressor (1) is If the capacity is not the minimum capacity, the determination in step ST8 is N.
It becomes O.

Thereafter, in step ST9, the compressor
(1) is performed, and the capacity of the compressor (1) is fixed for a predetermined time to prevent hunting of the capacity change. In step ST10, the capacity step N is linked with the electric expansion valve (5). In step ST11, the operation frequency of the compressor (1) is controlled, that is, the second displacement reducing means (14) controls the operating frequency of the compressor (1). , The capacity step N of the compressor (1) is 2 steps N
Will only be reduced. After that, the above step ST2
And the above operation is repeated. As a result,
When the external heat exchange temperature Tc suddenly rises, the capacity of the compressor (1) is increased by 2
It will be reduced by step N.

In step ST5, the compressor
If the capacity step N of (1) is smaller than 4, the determination is NO
Then, the process proceeds to step ST13. Since the capacity of the compressor (1) is low, the step change amount dN is set to −1, and the process proceeds to step ST7.
Will be moved to. Then, the above operation is performed.

In step ST8, the compressor
If the capacity step N of (1) is 2, the determination is YES, the process moves to step ST14, and the frequency OFF circuit is executed. That is, if the capacity step N is 2, the compressor
Since the capacity of (1) is the minimum, the operation of the compressor (1) is stopped. Thereafter, the process proceeds to step ST15, where the thermostat is turned off and the process returns to the main flow.

In the heating cycle, in step ST4, the second rate-of-increase determining means (13) determines whether the internal heat exchange temperature Te, which is the condensing temperature, has exceeded 54 ° C., and for 15 seconds. It is determined whether the temperature has risen by 2 ° C. or more. If the internal heat exchange temperature Te is equal to or lower than 54 ° C. or does not increase by 2 ° C. or more in 15 seconds even if the internal heat exchange temperature exceeds 54 ° C., the process proceeds to step ST2, and normal capacity control is performed. Specifically, the capacity step N of the compressor (1)
Is set based on the discharge pipe temperature Td, and the first capacity reducing means (11) reduces the capacity of the compressor (1) by one step N when the internal heat exchange temperature Te exceeds 56 ° C. When the internal heat exchange temperature Te exceeds 57.5 ° C., the capacity of the compressor (1) is reduced by one step N.

On the other hand, in the step ST4, the second rate-of-increase determining means (13) determines that the internal heat exchange temperature Te, which is the condensation temperature, is 54
If it is determined that the temperature has exceeded ℃ and the temperature has risen by 2 ° C. or more in 15 seconds, a rapid rise signal is output, and the process proceeds to step ST5. Thereafter, as in the cooling cycle, the second capacity reducing means (14) reduces the capacity of the compressor (1) by two steps N based on the determination by the second increasing rate determining means (13). Will be. As a result, the capacity of the compressor (1) is reduced by two steps N when the internal heat exchange temperature Te rises sharply.

Therefore, according to the present embodiment, when the increase rate of the external heat exchange temperature Tc or the internal heat exchange temperature Te, which is the condensing temperature, is large, the reduction capacity of the compressor (1) is increased. In an overload state such as at the time of start-up, an increase in high-pressure refrigerant pressure can be reliably suppressed. As a result, the operation of the high pressure switch (HPS) can be suppressed, so that the air conditioning operation can be continued and the comfort can be improved.

In addition, since the capacity of the compressor (1) is reduced in the heating cycle at a lower condensing temperature than in the cooling cycle, the high-pressure refrigerant pressure can be reliably reduced even in the poor response due to the length of the pipe. Since the rise can be suppressed and the operation of the high pressure switch (HPS) can be suppressed, the comfort can be improved.

Further, as an embodiment of the invention according to claim 1, the condensing temperature, which is the second set temperature, is set to the same temperature in the cooling cycle and the heating cycle in step ST4. The first rate-of-increase determining means (12) of the previous embodiment constitutes one rate-of-increase determining means (12) for determining a rapid rise in the condensing temperature. Other configurations and operations are the same as those in the cooling cycle of the previous embodiment. As a result, similarly to the previous embodiment, it is possible to reliably suppress an increase in the high-pressure refrigerant pressure in an overload state such as during startup.

In each of the embodiments, a separate type air conditioner has been described, but the present invention can be applied to various types of air conditioners.

In each of the embodiments, the external heat exchange sensor (Thc) and the internal heat exchange sensor (Thc) are used as the saturation temperature detecting means.
Although e) is provided, it goes without saying that a pressure sensor or the like may be used.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a refrigerant circuit diagram illustrating a refrigerant piping system of the air conditioner.

FIG. 3 is a control flow chart showing control for reducing compressor capacity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 3 Outdoor heat exchanger (heat source side heat exchanger) 5 Electric expansion valve (expansion mechanism) 6 Indoor heat exchanger (use side heat exchanger) 9 Refrigerant circuit 10 Controller 11 First capacity reduction means 12 Ascent rate judgment Means (first rise rate determination means) 13 Second rise rate determination means 14 Second capacity reduction means Thc External heat exchange sensor (saturation temperature detection means) The internal heat exchange sensor (saturation temperature detection means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F25B 1/00 371 F24F 11/02 102

Claims (2)

(57) [Claims] A refrigerant circuit in which a variable capacity compressor (1), a heat source side heat exchanger (3), an expansion mechanism (5), and a use side heat exchanger (6) are connected in order. 9) a saturation temperature detecting means (Thc, The) for detecting a saturation temperature corresponding to the condensing pressure in the refrigerant circuit (9), and a condensation temperature detected by the saturation temperature detecting means (Thc, The). When the pressure-equivalent saturation temperature rises to the first set temperature, first capacity reduction means (11) for reducing the capacity of the compressor (1) by a first predetermined amount set in advance, and the saturation temperature detection means (Thc, Thc, When the condensing pressure equivalent saturation temperature detected by The) rises to a second set temperature lower than the first set temperature, the rate of increase of the condensing pressure equivalent saturated temperature is determined, and if the increase rate is not less than a predetermined value. A rising rate determining means (12) for outputting a steep rising signal, and when the rising rate determining means (12) outputs a steep rising signal, the compressor ( 1) a second capacity reduction means (14) for reducing the capacity of (1) by a second predetermined amount larger than the first predetermined amount. 2. A variable capacity compressor (1), a heat source side heat exchanger (3), an expansion mechanism (5), and a use side heat exchanger (6) are connected in order to provide a cooling cycle and a heating cycle. In an air conditioner provided with a refrigerant circuit (9) capable of reversible operation with a cycle, a saturation temperature detecting means (Thc, The) for detecting a saturation temperature corresponding to a condensing pressure in the refrigerant circuit (9); When the condensing pressure equivalent saturation temperature detected by the means (Thc, The) rises to the first set temperature, the first capacity reducing means (11) for reducing the capacity of the compressor (1) by a first predetermined amount set in advance. When the condensing pressure equivalent saturation temperature during the cooling cycle detected by the saturation temperature detecting means (Thc, The) rises to a second set temperature lower than the first set temperature, the rate of increase of the condensing pressure equivalent saturation temperature And if the rate of increase is greater than or equal to a predetermined value, a first rate of increase determination that outputs a sudden increase signal Step (12), when the condensing pressure equivalent saturation temperature during the heating cycle detected by the saturation temperature detecting means (Thc, The) rises to a third set temperature lower than the second set temperature, Determining a rate of temperature rise, and if the rate of rise is greater than or equal to a predetermined value, a second rise rate determination means (13) for outputting a rapid rise signal; and the first rise rate determination means (12) or the second rise rate. Judgment means (1
And 3) a second capacity reduction means (14) for reducing the capacity of the compressor (1) by a second predetermined amount larger than the first predetermined amount when the 3) outputs a steep rise signal. Operation control device for air conditioner.