JPH07174416A - Freezing cycle apparatus - Google Patents

Abstract

PURPOSE:To make optimum temperature of a refrigerant discharged from a compressor without causing severe variations in an operation frequency by controlling the operation frequency of the compressor with first and second control means when detected temperature by a second temperature sensor is lower than a first set value or higher than that. CONSTITUTION:A first temperature sensor 51 for detecting the temperature of a load is provided on an indoor controller 50, and a second temperature sensor 9 for detecting the temperature of a discharged refrigerant from a compressor is provided on an outdoor control part 40. These indoor control part 50 and outdoor control part 40 are connected through a power supply line and a serial signal line. When detected temperature by the second temperature sensor 9 is lower than a first set value, a target value for operation frequency of the compressor is set in response to the total sum of air conditioning loads informed from the indoor control part 50 for matching it with actual operation frequency. In contrast, when a value of the second temperature sensor 9 exceeds the first set value, a second target value is determined in response to a difference with the second set value matching it with the actual operation frequency for stabilized optimum state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle device used in an air conditioner or the like.

[0002]

2. Description of the Related Art In a refrigeration cycle apparatus having a variable capacity compressor, an optimum capacity corresponding to a load is obtained by controlling an operating frequency F of the compressor according to a difference between a load temperature and a target temperature. There is something to gain.

In such a refrigeration cycle apparatus, the temperature of refrigerant discharged from the compressor may rise abnormally due to the influence of overload operation. If the operation continues with this abnormal increase, the lubricating oil filled in the compressor will be decomposed or deteriorated, and the life of the compressor will be adversely affected.

In order to prevent such a problem, the temperature Td of the refrigerant discharged from the compressor is detected and the detected temperature Td is detected.
There is a method in which the control pattern of the operating frequency F is switched according to. An example is shown in FIG.

That is, a plurality of zones are defined for the discharge refrigerant temperature Td. When Td is in the A zone below 113 ° C, the operating frequency F is controlled according to the difference between the load temperature and the target temperature. That is, the normal operation frequency control is executed.

When Td rises and enters the B zone equal to or higher than 113 ° C., the operating frequency F is first lowered by 30 Hz. After that, the operating frequency F is lowered by 5 Hz every 3 minutes.
This control is continued until it returns to the A zone where Td is less than 110 ° C. In addition, with respect to the decrease of the operating frequency F, the minimum allowable operating frequency Fmin (for example, 28 Hz) is limited.

After the control of the B zone, when returning to the A zone where Td is less than 110 ° C., 5 Hz is subtracted from the operating frequency F immediately before entering the control of the B zone, and the value obtained by this subtraction is the maximum allowable operating frequency. It is set as Fmax, and the normal operation frequency control is resumed. If Td drops below 100 ° C,
Remove the maximum allowable operating frequency Fmax.

By repeating this operation, Td is stabilized in the A zone. However, in some cases, the rise in Td cannot be suppressed and Td may exceed 122 ° C. In this case, immediately stop the operation of the compressor.

[0009]

In the above control pattern, when Td is in the A zone, the operation frequency control is only performed to bring the temperature of the load to the target temperature.
The operating frequency control for suppressing the increase of d is not performed.

For this reason, Td may suddenly rise from A zone to B zone with a slight overshoot.
Moreover, when Td enters the B zone, the operating frequency F is suddenly lowered.

Such a sudden increase in Td and a sudden decrease in operating frequency F eventually result in a large change in operating frequency F, which causes a large change rather than stabilizing Td. The present invention takes the above circumstances into consideration, and the purpose thereof is to determine the temperature of the refrigerant discharged from the compressor,
(EN) A refrigeration cycle device capable of stabilizing an optimal state without causing a large change in operating frequency, preventing decomposition and deterioration of lubricating oil in a compressor, and improving the life of the compressor.

[0012]

A refrigeration cycle apparatus of a first invention is a refrigeration cycle in which a compressor, a condenser, a pressure reducer, and an evaporator are connected by piping, and a first temperature for detecting a temperature of a load. A sensor, a second temperature sensor for detecting the temperature of the refrigerant discharged from the compressor, and a detection temperature of the first temperature sensor and a target temperature when the detection temperature of the second temperature sensor is less than a first set value. The first control means for controlling the operating frequency of the compressor according to the difference and the detected temperature of the second temperature sensor are the first
Second control means for controlling the operating frequency of the compressor according to the difference between the detected temperature of the second temperature sensor and the second set value (> the first set value) and the amount of change in the difference when the set value or more; Equipped with.

In the refrigeration cycle apparatus of the second invention, the second control means in the first invention is such that when the temperature detected by the second temperature sensor is equal to or higher than the first set value, the temperature detected by the first temperature sensor and the target temperature. The first target value of the operating frequency is set according to the difference between the temperature and the second temperature sensor, and the operation is performed according to the difference between the detected temperature of the second temperature sensor and the second set value (> the first set value) and the change amount of the difference. A second target value of the frequency is set, and the operating frequency of the compressor is adjusted to the smaller one of the first target value and the second target value.

In the refrigeration cycle apparatus of the third invention, the second control means in the first or second invention changes the control execution interval in accordance with the operating frequency of the compressor. Fourth
In addition to the first or second invention, the refrigeration cycle apparatus of the invention of claim 2 is such that the temperature detected by the second temperature sensor is the third set value (> second
A third control means is provided for stopping the operation of the compressor when the value is equal to or more than the set value.

[0015]

In the refrigeration cycle apparatus of the first invention, when the temperature of the refrigerant discharged from the compressor is less than the first set value, the operating frequency of the compressor is controlled according to the difference between the temperature of the load and the target temperature. When the discharged refrigerant temperature is equal to or higher than the first set value, the operating frequency of the compressor is controlled according to the difference between the discharged refrigerant temperature and the second set value (> the first set value) and the change amount of the difference.

In the refrigeration cycle apparatus of the second invention, when the refrigerant discharge temperature of the compressor is less than the first set value, the operating frequency of the compressor is controlled according to the difference between the load temperature and the target temperature. When the discharge refrigerant temperature is equal to or higher than the first set value, the first target value of the operating frequency is set according to the difference between the load temperature and the target temperature, and the discharge refrigerant temperature and the second set value (>
The second target value of the operating frequency is set according to the difference from the first set value) and the amount of change in the difference, and the operating frequency of the compressor is adjusted to the smaller one of the first target value and the second target value. To be

In the refrigeration cycle apparatus of the third invention, the control execution interval when the discharged refrigerant temperature is equal to or higher than the first set value changes depending on the operating frequency of the compressor. A refrigeration cycle apparatus of a fourth invention is, in addition to the first or second invention,
When the temperature detected by the second temperature sensor is equal to or higher than the third set value (> the second set value), the operation of the compressor is stopped.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, A is an outdoor unit and B is
₁ and B ₂ are indoor units. The following refrigeration cycle is configured in these units.

An outdoor heat exchanger 3 is connected to a discharge port of a variable capacity compressor 1 through a four-way valve 2. The liquid side main pipe W is connected to the outdoor heat exchanger 3. The liquid side main pipe W is branched into liquid side branch pipes W ₁ and W ₂ . The indoor heat exchanger _{1 is} attached to the liquid side branch pipes W ₁ and W _2.
2, 22 are connected. The liquid-side branch pipes W ₁ and W ₂ are provided with electric expansion valves 11 and 21 as pressure reducers. The electric expansion valves 11 and 21 are pulse motor valves whose opening continuously changes according to the number of drive pulses supplied. Hereinafter, the electric expansion valve will be referred to as PMV.

A gas side branch pipe G is attached to the indoor heat exchangers 12 and 22.
₁ , G ₂ are connected. The gas side branch pipes G ₁ and G ₂ are gathered together in the gas side main pipe G, and the gas side main pipe G is connected to the suction port of the compressor 1 via the four-way valve 2.

An outdoor fan 4 is provided near the outdoor heat exchanger 3. In the pipe between the discharge port of the compressor 1 and the four-way valve 2,
One end of the defrosting bypass pipe 5 is connected, and the other end of the bypass pipe 5 is connected to the liquid side main pipe W. A two-way valve 6 is provided in the bypass pipe 5. A temperature sensor 7 is attached to the outdoor heat exchanger 3.
Is installed. A temperature sensor 8 is attached to a pipe between the four-way valve 2 and the suction port of the compressor 1. A temperature sensor 9 (second temperature sensor that detects the temperature of the refrigerant discharged from the compressor 1) is attached to a pipe connected to the discharge port of the compressor 1.

Indoor fans 13, 23 are provided near the indoor heat exchangers 12, 22. A temperature sensor 14 is attached to the indoor heat exchanger 12. A temperature sensor 24 is attached to the indoor heat exchanger 22. Temperature sensor on the gas side branch pipe G ₁ 1
5 is attached. A temperature sensor 25 is attached to the gas side branch pipe G ₂ .

The control circuit is shown in FIG. Commercial AC power supply 30
The outdoor control unit 40 of the outdoor unit A is connected to the. The outdoor control unit 40 includes a microcomputer and its peripheral circuits. PMV1 is added to the outdoor control unit 40.
1, 21, two-way valve 6, four-way valve 2, outdoor fan motor 4
M, temperature sensors 7, 8, 9, 15, 25, and the inverter circuit 41 are connected.

The inverter circuit 41 rectifies the voltage of the power supply 30, converts it into a voltage of a frequency and level according to a command from the outdoor control section 40, and outputs it. This output becomes drive power for the compressor motor 1M.

The indoor units B ₁ and B ₂ each include an indoor control section 50. The indoor control unit 50 includes a microcomputer and its peripheral circuits. This indoor control unit 5
0, the indoor temperature sensor (first temperature sensor for detecting the temperature of the load) 51, the temperature sensor 14 (and 24), the remote control type operation device 52, the indoor fan motor 13
M (and 23M) are connected.

The indoor control unit 50 and the outdoor control unit 40 are connected by a power supply line ACL and a serial signal line SL, respectively. The indoor control unit 50 and the outdoor control unit 40 perform overall control of the air conditioner by mutually performing power supply voltage-synchronized data transfer using the serial signal line SL.

Each indoor control section 50 mainly includes the following functional means. [1] A means for notifying the outdoor control unit 40 of the operating conditions (including the cooling mode command, the heating mode command, the target value Ts of the indoor temperature, etc.) set by the operation unit 52.

[2] Temperature Ta detected by the room temperature sensor 51
And means for detecting the difference ΔT (= Ta−Ts) between the indoor temperature target value Ts set by the operating device 52 as an air conditioning load and notifying the outdoor controller 40 of the air conditioning load ΔT.

[3] A means for notifying the outdoor control section 40 of the detected temperature Tc of the temperature sensor 14 (and 24) and the detected temperature Ta of the indoor temperature sensor 51. The outdoor control unit 40 mainly includes the following functional means.

[1] Based on the cooling mode command informed from each outdoor control unit 50, the refrigerant discharged from the compressor 1 is supplied with the four-way valve 2, the outdoor heat exchanger 3, the PMVs 11 and 21, the indoor heat exchangers 12 and 22, A means for returning to the compressor 1 through the four-way valve 2 to execute a cooling operation.

[2] The four-way valve 2 is switched based on the heating mode command informed from each outdoor control section 50, and the refrigerant discharged from the compressor 1 is transferred to the four-way valve 2, the indoor heat exchangers 12, 22 and the PMV.
11 and 21, the outdoor heat exchanger 3, the four-way valve 2 to return to the compressor 1 to perform heating operation.

[3] Temperature T detected by the temperature sensor 9 during operation
When d is less than the first set value (105 ° C.) (A zone), the operating frequency F of the compressor 1 (= the output frequency of the inverter circuit 41 is determined according to the total air conditioning load ΔT notified from each indoor control unit 50). first sets a target value F ₁ for), means to adjust the actual operating frequency F to the first target value F ₁ (first control means).

[4] The temperature Td detected by the temperature sensor 9 is the first
When it is equal to or higher than the set value (105 ° C.) (zone B), the first target value F ₁ for the operating frequency F is set according to the total of the air conditioning load ΔT notified from each indoor control unit 50, and
Temperature Td detected by temperature sensor 9 and second set value (110 ° C) T
The operating frequency F according to the difference Tdd (= Tds-Td) from ds and the change amount ΔTdd (= Tdd-previous Tdd) of the difference Tdd.
The second target value F ₂ for the
Means for adjusting the actual operating frequency F to the smaller one of ₁ and the second target value F ₂ (second control means).

[5] The temperature Td detected by the temperature sensor 9 is the third
A means (third control means) for stopping the operation of the compressor 1 when the value is higher than the set value (122 ° C.) (C zone). [6] During cooling operation, the difference (= Tg−Tc) between the temperature Tg detected by the temperature sensor 15 and the temperature Tc detected by the temperature sensor 14 is detected as the superheat degree SH of the refrigerant in the indoor heat exchanger (evaporator) 12. , The difference between the temperature Tg detected by the temperature sensor 25 and the temperature Tc detected by the temperature sensor 24 is calculated as the indoor heat exchanger (evaporator).
A means for detecting the superheat degree SH of the refrigerant at 22.

[7] Each superheat degree SH detected during cooling operation
Is a first control unit for cooling, which controls the opening of each of the PMVs 11 and 21 so that the set value SHs becomes a preset value SHs.

[8] During heating operation, the difference between the temperature Te detected by the temperature sensor 7 and the temperature Ts detected by the temperature sensor 8 (= Ts-
Te) is the superheat degree SH of the refrigerant in the outdoor heat exchanger (evaporator) 3.
Means to detect as.

[9] Means for controlling the opening degree of each of the PMVs 11 and 21 during heating operation so that the detected superheat degree SH becomes a preset value SHs predetermined for heating. [10] A means for periodically performing the defrosting operation on the outdoor heat exchanger 3 by opening the two-way valve 6 during the heating operation. When the two-way valve 6 is opened, the high temperature refrigerant discharged from the compressor 1 is injected into the outdoor heat exchanger 3.

Next, the operation of the above configuration will be described. When the cooling mode is set in each operation device 52, the refrigerant discharged from the compressor 1 flows in the direction of the solid arrow in FIG. 1, the outdoor heat exchanger 3 functions as a condenser, and the indoor heat exchangers 12 and 22 function as evaporators. Function. As a result, the cooling operation is executed.

When the heating mode is set by each operating device 52, the four-way valve 2 is switched and the refrigerant discharged from the compressor 1 is discharged as shown in FIG.
, The indoor heat exchangers 12 and 22 function as condensers, and the outdoor heat exchanger 3 functions as an evaporator. As a result, the heating operation is executed.

During the cooling and heating operations, the operation frequency control shown in FIGS. 3 to 6 is executed. Indoor unit B
_The room temperature Ta is detected by ₁ and B ₂ , and the room temperature T is detected.
difference Δ between a and the target temperature Ts set by each remote controller 52
T is detected as the air conditioning load. The first target value F ₁ for the operating frequency F is determined according to the total value of these air conditioning loads ΔT. Then, the first target value F ₁ is the target value F ₀
Is replaced by

The temperature Td of the refrigerant discharged from the compressor 1 is detected by the temperature sensor 9, and the detected temperature Td is compared with the zone control condition shown in FIG. When Td is less than 113 ° C, the flag FLAG is set to "0". This flag
FLAG is for storing whether Td entered the C zone of 122 ° C or higher, which is an abnormal temperature range. "0"
Indicates that it is not in the C zone yet.

When Td is in the A zone below 105 ° C.,
The actual operating frequency F is controlled so as to match the above target value F ₀ . That is, it is a normal operation frequency control. In addition,
Zone A is set to a lower temperature side than the conventional zone A shown in FIG.

When Td rises and enters the zone B above 105 ° C., the time count t is started, and the time count t is compared with the set time t ₁ . The set time t ₁ is
It is determined by the t ₁ determination routine shown in FIG. That is, when the target value F ₀ (= F ₁ ) is 50 Hz or more and less than 100 Hz, t ₁ = 30 seconds, and when it is 100 Hz or more and less than 150 Hz, t ₁ = 2.
When 0 seconds or 150 Hz or more, t ₁ = 10 seconds is determined. The B zone is wider on the low temperature side than the conventional B zone shown in FIG. 7, and has a wide area including the conventional A zone.

When the time count t reaches the set time t ₁ , the difference between Td and Tds (110 ° C.) Tdd (= Tds-Td)
Is calculated, and the amount of change in the difference Tdd is ΔTdd (= Tdd
-Previous time Tdd) is calculated. The correction value Δ for the actual operating frequency F is calculated by the following formula using these calculation results.
F ₀ is calculated. Note that G ₁ = 1.0 and G ₂ = 1.0.

ΔF ₀ = G ₁ Tdd + G ₂ ΔTdd For example, when the time count t reaches the set time t ₁ , the Td is 109 ° C., and the previous T ₁ hour before that is t _1.
It is assumed that d is 106 ° C. In this case, the current Tdd =
110 ° C-109 ° C = 1 ° C, the previous Tdd = 110 ° C-106 ° C =
Since it is 4 ° C., ΔTdd = 1 ° C.−4 ° C. = − 3 ° C. is obtained.

Therefore, ΔF ₀ = G ₁ · (1 ° C) + G ₂ ·
(−3 ° C.) = − 2 Hz is obtained. It is also assumed that the Td at the time when the time count t reaches the set time t ₁ is 113 ° C., and the previous Td before the time t ₁ is 109 ° C. In this case, Tdd = 110 ° C-113 ° C = -3 ° C at the present time and Tdd = 110 ° C-109 ° C = 1 ° C in the previous time, so ΔTdd =
(−3 ° C.) − (− 1 ° C.) = − 2 ° C. is obtained.

Therefore, ΔF ₀ = G ₁ · (−3 ° C.) + G ₂
・ (−2 ℃) = − 5Hz is obtained. The actual operating frequency F is stored as the actual operating frequency value Ff, and the above-mentioned ΔF ₀ is added to the Ff to obtain the second target value F ₂ (= Ff + ΔF
₀ ) is set.

A first target value F ₁ set on the basis of the total of the air conditioning loads ΔT and a second target value F including a correction value ΔF _0
2 is compared, and the smaller one is set as the target value F ₀ . For example, if F ₂ > F ₁ , then F ₁
Is set as the target value F ₀ . If F ₂ ≦ F ₁ , then
F ₂ is set as the target value F ₀ .

The set target value F ₀ is the actual operating frequency value F
It is updated and stored as f. Then, the operating frequency F is controlled so as to match the target value F ₀ . In this way, the B zone is expanded to a lower temperature side than the conventional B zone and set to a wide area including the conventional A zone, and as soon as Td enters the B zone, the size of Td in the B zone is Is determined based on Tds (that is, Tdd), and the slope of the change in Td is A
Judgment including the history from the zone (that is, ΔTdd), and the correction value ΔF for the operating frequency F according to these judgment results
_{Since 0} is determined, it is possible to correct the operating frequency F to a necessary minimum while avoiding an increase in Td overshoot. Therefore, Td can be smoothly lowered to the optimum state, that is, the A zone, and stabilized without the operating frequency F drastically decreasing. With this, it is possible to prevent decomposition and deterioration of the lubricating oil in the compressor 1,
The life of the compressor 1 can be improved.

Particularly, since the execution interval t of the control for obtaining the correction value ΔF ₀ changes according to the target value F ₀ (that is, the operating frequency F), the control followability with respect to the change of Td becomes good, and the stability of Td becomes stable. Can greatly contribute to

After the control of the B zone, when returning to the A zone where Td is less than 105 ° C., the normal operation frequency control is resumed. However, despite control of the B zone, Td is 122 ° C.
When the temperature rises to the above C zone, the flag FLAG is set to "1", the target value F ₀ is set to ₀ Hz, and the operation of the compressor 1 is stopped. After this stop, flag FL
Since AG is “1”, the boundary point between the B zone and the C zone is 113 ° C.

By forcibly stopping the operation of the compressor 1 as described above, it is possible to prevent the decomposition and deterioration of the lubricating oil in the compressor 1 as well as to prevent the temperature rise of the compressor motor 1M, which in turn can prevent it. Insulation deterioration of the winding of the compressor motor 1M is prevented.

After that, when returning to the B zone where Td is less than 113 ° C., the compressor 1 is started and the control of the B zone is restarted. On the other hand, during the heating operation, the two-way valve 6 is periodically opened to perform the defrosting operation on the outdoor heat exchanger 3. That is, when the two-way valve 6 is opened, the high temperature refrigerant discharged from the compressor 1 is injected into the outdoor heat exchanger 3, and the heat of the high temperature refrigerant removes the frost adhering to the outdoor heat exchanger 3. .

During the defrosting operation, the temperature Te of the outdoor heat exchanger 3 is detected by the temperature sensor 7, and when the detected temperature Te reaches, for example, 2 ° C. or more, it is determined that the defrosting is completed. The defrosting operation is ended and the heating operation is resumed.

At the end of this defrosting operation, as shown in FIG. 6, it is determined whether Td is lower than a predetermined value Td ₁ at a constant time tas based on the time count ta. If Td is lower than the predetermined value Td ₁ , the operating frequency F is set to the predetermined low frequency Fa for the constant time tbs based on the time count tb.

After the elapse of the constant time tbs, even if Td is still lower than the predetermined value Td ₁ , the normal operation frequency control is resumed when the constant time tas elapses. Immediately after the defrosting operation is completed, the degree of dilution of the lubricating oil in the compressor 1 is high, and if the operating frequency F rises as it is, the lubricating oil will be decomposed or deteriorated. Therefore, at the end of defrosting,
The operating frequency F is set to the low frequency Fa while Td is still low, and the above-mentioned problem is solved. In addition, in the said Example, although the application to an air conditioner was demonstrated, it is applicable similarly to other apparatuses, such as a refrigerator.

[0057]

As described above, according to the present invention, when the discharge refrigerant temperature of the compressor is less than the first set value, the operating frequency of the compressor is controlled according to the difference between the load temperature and the target temperature. When the discharge refrigerant temperature is equal to or higher than the first set value,
Since the operating frequency of the compressor is controlled according to the difference between the discharged refrigerant temperature and the second set value (> the first set value) and the amount of change in the difference, the temperature of the refrigerant discharged from the compressor is controlled. It is possible to provide a refrigeration cycle device capable of stabilizing the engine in an optimum state without causing a large fluctuation in the operating frequency, preventing decomposition and deterioration of the lubricating oil in the compressor, and improving the life of the compressor.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a control circuit of the embodiment.

FIG. 3 is a flowchart for explaining the operation of the embodiment.

FIG. 4 is a diagram showing zone control conditions in the embodiment.

FIG. 5 is a flowchart of a t ₁ determination routine in the same embodiment.

FIG. 6 is a flowchart of a defrosting control routine in the embodiment.

FIG. 7 is a diagram showing a conventional zone control condition.

[Explanation of symbols]

A ... outdoor unit, B _1, B ₂ ... indoor unit, 1 ... variable capacity type compressor, 3 ... outdoor heat exchanger, 11 and 21 ... P
MV, 12, 22 ... Indoor heat exchanger, 9 ... Temperature sensor, 4
0 ... Indoor control unit, 41 ... Inverter circuit, 50 ... Outdoor control unit, 51 ... Indoor temperature sensor.

Claims (4)

[Claims] 1. A refrigeration cycle in which a compressor, a condenser, a pressure reducer, and an evaporator are connected by piping, a first temperature sensor for detecting a temperature of a load, and a temperature of a refrigerant discharged from the compressor. A second temperature sensor for detecting, and when the temperature detected by the second temperature sensor is less than a first set value, the operating frequency of the compressor is controlled according to the difference between the temperature detected by the first temperature sensor and the target temperature. And a difference between the detected temperature of the second temperature sensor and the second set value (> the first set value) and the difference thereof when the detected temperature of the second temperature sensor is equal to or higher than the first set value. A refrigeration cycle apparatus comprising: a second control unit that controls an operating frequency of the compressor according to a change amount. 2. The refrigeration cycle apparatus according to claim 1, wherein the second control unit has a first temperature detected by the second temperature sensor.
When the value is equal to or more than the set value, the first target value of the operating frequency is set according to the difference between the detected temperature of the first temperature sensor and the target temperature, and the detected temperature of the second temperature sensor and the second set value (>
The second target value of the operating frequency is set according to the difference from the first set value) and the amount of change in the difference, and the operating frequency of the compressor is adjusted to the smaller one of the first target value and the second target value. . 3. The refrigeration cycle apparatus according to claim 1 or 2, wherein the second control means changes a control execution interval according to an operating frequency of the compressor. 4. The refrigeration cycle apparatus according to claim 1, wherein the operation of the compressor is stopped when the temperature detected by the second temperature sensor is equal to or higher than a third set value (> second set value). A third control means is provided.