JP3213662B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art An air conditioner is provided with an outside air temperature sensor for detecting an outside air temperature, and performs, for example, speed control of an outdoor fan, current release control of an inverter, and correction control of a set indoor temperature in accordance with the detected temperature. is there.

[0003] The outside air temperature sensor is generally mounted on the outdoor unit, but in this mounting, it is necessary to take care that the outside air temperature sensor is not affected by solar radiation or radiant heat of the outdoor heat exchanger.

[0004]

However, whether or not the outside air temperature sensor is affected by solar radiation is often determined by the installation condition of the outdoor unit, and it is actually difficult to select a mounting location. Eventually, there is a concern that the influence of solar radiation cannot be avoided, and that it is not possible to properly detect the outside air temperature, thereby impairing driving control.

[0005] It is conceivable that an operator selects an installation location of the outside air temperature sensor in the outdoor unit at the time of installation. However, this is troublesome for the operator, and there is a concern that the installation may be performed incorrectly. is there.

[0006] The present invention has been made in view of the above circumstances,
Its purpose is to capture the outside air temperature without the need for an outside air temperature sensor, which eliminates the need for consideration of mounting locations as when using an outside air temperature sensor, and also has the adverse effect of solar radiation etc. Another object of the present invention is to provide an air conditioner capable of detecting the outside air temperature with high reliability while reducing the work load at the time of installation and reducing the cost.

[0007]

[0008]

[0009]

Means for Solving the Problems The air conditioner of the first invention, a variable capacity compressor, an outdoor heat exchanger, a pressure reducer, to connect the indoor heat exchanger constitutes a refrigeration cycle, and the compressor An air conditioner that controls the output frequency of the inverter according to the air-conditioning load, and a temperature sensor that detects the temperature of the outdoor heat exchanger. Means for taking the detected temperature of the temperature sensor as the outside air temperature, means for estimating the outside air temperature by correction according to the output frequency of the inverter with respect to the detected temperature of the temperature sensor after a predetermined time from the start of operation, A means for obtaining a difference from the temperature detected by the temperature sensor at the start of operation, a means for taking the detected temperature of the temperature sensor at the start of operation as the outside temperature when the difference is equal to or greater than a set value, and And means for the becomes a value less Only then the estimated value taking as outside air temperature, and control means for controlling the operation using the outside air temperature the taken.

An air conditioner according to a second aspect of the present invention is an inverter that connects a variable capacity compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger to form a refrigeration cycle and supplies driving power to the compressor. And an outdoor fan that blows air to the outdoor heat exchanger.In an air conditioner that controls the output frequency of the inverter according to the air conditioning load, a temperature sensor that detects the temperature of the outdoor heat exchanger and a driving current of the compressor are provided. It comprises a current sensor for detecting, and a means for correcting the temperature detected by the temperature sensor according to the output frequency and the drive current to estimate the outside air temperature.

[0011]

[0012]

In the air conditioner according to the first aspect of the present invention, the temperature of the outdoor heat exchanger at the start of operation is taken as the outside air temperature for a predetermined time from the start of operation, and the temperature of the outdoor heat exchanger is converted to the inverter temperature after a predetermined time from the start of operation. Estimates the outside air temperature by correcting according to the output frequency of the outdoor heat exchanger, and calculates the difference between this estimated value and the temperature of the outdoor heat exchanger at the start of operation. Is detected as the outside temperature, and when the difference becomes equal to or less than the set value, the above estimated value is first taken as the outside temperature, and the taken outside temperature is used for operation control. In the air conditioner of the second invention, the temperature of the outdoor heat exchanger is corrected according to the output frequency of the inverter and the drive current to estimate the outside air temperature.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the outdoor unit A
The indoor unit B is equipped with a heat pump refrigeration cycle.

Reference numeral 1 denotes a variable capacity compressor. An outdoor heat exchanger 3 is connected to a discharge port of the compressor 1 via a four-way valve 2.
An indoor heat exchanger 5 is connected to the outdoor heat exchanger 3 via an expansion valve 4 which is a decompressor.
Is connected to the suction port of the compressor 1 via the four-way valve 2.

An outdoor fan 6 is provided near the outdoor heat exchanger 3 and an indoor fan 7 is provided near the indoor heat exchanger 5. The heat exchanger temperature sensor 11 is attached to the outdoor heat exchanger 3.
An indoor temperature sensor 12 is provided in a suction air passage formed by the indoor fan 7.

FIG. 1 shows a control circuit. The indoor control unit 20 of the indoor unit B is connected to the commercial AC power supply 30. Then, the outdoor control unit 4 of the outdoor unit A is connected to the indoor control unit 20 via the power line ACL and the serial signal line SL.
0 is connected.

The indoor control unit 20 comprises a microcomputer and its peripheral circuits. In this indoor control unit 20,
The light receiving unit 21, the indoor fan motor 6M, and the indoor temperature sensor 12 are connected. The light receiving unit 21 receives infrared light transmitted from a remote control type operation device (hereinafter, abbreviated as a remote controller) 22.

The outdoor controller 50 comprises a microcomputer and its peripheral circuits. The outdoor control unit 50 includes a four-way valve 2, an outdoor fan motor 6M, a heat exchanger temperature sensor 1
1 and the inverter circuit 41 are connected. The inverter circuit 41 rectifies the voltage of the power supply line ACL, converts the rectified voltage into a voltage of a predetermined frequency (and level) according to a command from the outdoor control unit 40, and outputs the voltage. This output is the driving power of the compressor motor 1M.

Here, the indoor control unit 20 and the outdoor control unit 40 perform data transfer synchronized with the power supply voltage through the serial signal line SL to control the air conditioner, and have the following functional units.

[1] The refrigerant discharged from the compressor 1 flows in the direction of the solid arrow shown in FIG. 2 to form a cooling cycle, and the outdoor heat exchanger 3 is used as a condenser and the indoor heat exchanger 5 is used as an evaporator. Means for functioning and performing a cooling operation or a dry operation (= weak cooling operation).

[2] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the dashed arrow shown in FIG. 2 by switching the four-way valve 2, thereby forming a heating cycle and causing the indoor heat exchanger 5 to operate as a condenser and outdoor heat exchanger. Means for causing the heater 3 to function as an evaporator and performing a heating operation.

[3] Means for switching the four-way valve 2 and performing the defrosting operation on the outdoor heat exchanger 3 when the temperature detected by the heat exchanger temperature sensor 11 becomes lower than a predetermined value, for example, 0 ° C. or lower during heating.

[4] During cooling and heating, the difference ΔT between the detected temperature Ta of the indoor temperature sensor 12 and the set temperature Ts of the remote controller.
Means for determining the output frequency (the operating frequency of the compressor 1) F of the inverter circuit 41 in accordance with the difference ΔT.

[5] At a predetermined time t ₁ (for example, 60 seconds) from the start of operation, the heat exchanger temperature sensor 1 at the start of operation
Means for taking in the detected temperature Te as the outside air temperature To. [6] After a predetermined time t ₁ (for example, 60 seconds) from the start of operation,
The detected temperature Te of the heat exchanger temperature sensor 11 is output frequency F
Means for estimating the outside air temperature To.

[7] Control means for controlling operation using the taken-in or estimated outside air temperature To. Next, the operation of the above configuration will be described with reference to FIG.
When the start operation of the cooling operation is performed by the remote controller 22, the detected temperature Te of the heat exchanger temperature sensor 11 is read and stored in the memory in the control unit as the outside air temperature To. At the same time, a time count t is started.

Then, the compressor 1 is started, and the refrigerant discharged from the compressor 1 passes through the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, the indoor heat exchanger 5, and the four-way valve 2, and Returning to 1, a cooling cycle is formed. Thereby, the outdoor heat exchanger 3 functions as a condenser and the indoor heat exchanger 5 functions as an evaporator, and the room is cooled.

At the time of cooling, the detected temperature Ta of the room temperature sensor 12 is read, and the difference ΔT (= Ta−Ts) between the detected temperature Ta and the temperature Ts set by the remote controller 22 is obtained as the air conditioning load. Inverter circuit 4 has a value corresponding to this temperature difference ΔT.
An output frequency F (operation frequency of the compressor 1) F is set, and the capacity of the compressor 1 is controlled.

During operation, various controls are executed according to the outside air temperature To stored in the memory. For example, the speed tap of outdoor fan motor 6M is switched according to outside air temperature To. When the outside air temperature To is higher than a predetermined value, a current release control is performed to avoid an abnormal rise in the temperature of the inverter circuit 41. In order to obtain indoor comfort, the set temperature Ts is corrected according to the outside air temperature To.

After the time count t reaches the predetermined time t ₁ , the detected temperature Te of the heat exchanger temperature sensor 11 is sequentially read, and the correction value f (F (F) corresponding to the output frequency F of the inverter circuit 41 is obtained. ) Are sequentially read.

The correction value f (F) is a function of the output frequency F, and is stored in advance in the ROM in the control unit as the correction value setting condition shown in FIG. Further, the number of rotations of the outdoor blower 6 is stepwise (for example, three steps) according to the output frequency F.
Therefore, it is considered that the change in the number of revolutions of the blower 6 is added to this f (F). For example, when the output frequency F is 10 Hz, the correction value f (F) is set to a numerical value “−”.
1.0 "is read out. If the output frequency F is 36 Hz, a numerical value" -7.0 "is read out as the correction value f (F).
The correction value setting condition shown in FIG. 4 is for cooling, and although not shown, it is of course also prepared for heating.

The detected temperature Te is read, and the correction value f
When (F) is read, by the operation of the following equation using both the estimated value To ₁ of the outside air temperature is determined. To ₁ = Te + f (F) That is, between the heat exchanger temperature Te and the outside air temperature To,
As shown in FIG. 5, there is a proportional relationship with the output frequency F as a parameter.
There is always a 9.0 ° C difference between the heat exchanger temperature Te and the outside air temperature To. This temperature difference is defined as a correction value f (F).

When the estimated value To ₁ is obtained, it is calculated based on the outside air temperature T.
It is updated and stored in the memory in the control unit as o. Thereafter, the above-described tap switching, current release control, and set temperature correction are performed based on the estimated and updated outside air temperature To.

FIG. 6 shows the relationship between the heat exchanger temperature Te and the estimated value To _{1. Since the} operation is unstable at startup, the proportional relationship shown in FIG. _{Although 1} greatly deviates from the actual outside temperature, when the operation becomes stable some time after the start, the proportional relationship in FIG. 5 is established, and it is understood that the estimated value To ₁ approaches the actual outside temperature.

Therefore, for a predetermined time t ₁ from the start, the heat exchanger temperature Te at the start of the operation, which is substantially equal to the outside air temperature, is used as the outside air temperature To as it is. Then, after a predetermined time t _1, is an estimate To ₁ taken as the outside air temperature To. The outside air temperature To thus obtained is a stable value substantially equal to the actual outside air temperature, as shown in FIG.

As described above, by capturing the outside air temperature To from the heat exchanger temperature Te, an outside air temperature sensor is not required. Therefore, there is no need to consider the installation location, such as when using an outside air temperature sensor, and there is no adverse effect such as solar radiation, making it possible to detect the outside air temperature with high reliability while reducing the work load during installation. Become.

Moreover, the heat exchanger temperature sensor 11 is originally provided for detecting frost formation during heating, and is also used for detecting the outside air temperature. The cost can be reduced in addition to the fact that it becomes unnecessary.

Next, a second embodiment of the present invention will be described. Here, the indoor control unit 20 and the outdoor control unit 40
Has the following functional means. For other configurations, refer to
This is the same as the embodiment.

Here, the indoor control unit 20 and the outdoor control unit 40 perform data transfer synchronized with the power supply voltage through the serial signal line SL to control the air conditioner, and have the following functional units.

[1] The refrigerant discharged from the compressor 1 flows in the direction of the solid line arrow shown in FIG. 2 to form a cooling cycle, and the outdoor heat exchanger 3 is used as a condenser and the indoor heat exchanger 5 is used as an evaporator. Means for functioning and performing a cooling operation or a dry operation (= weak cooling operation).

[2] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the dashed arrow shown in FIG. 2 by switching the four-way valve 2, thereby forming a heating cycle and allowing the indoor heat exchanger 5 to operate as a condenser and an outdoor heat exchanger. Means for causing the heater 3 to function as an evaporator and performing a heating operation.

[3] Means for switching the four-way valve 2 and performing the defrosting operation on the outdoor heat exchanger 3 when the temperature detected by the heat exchanger temperature sensor 11 becomes lower than a predetermined value, for example, 0 ° C. or lower during heating.

[4] During cooling and heating, the difference ΔT between the detected temperature Ta of the indoor temperature sensor 12 and the set temperature Ts of the remote controller.
Means for determining the output frequency (the operating frequency of the compressor 1) F of the inverter circuit 41 in accordance with the difference ΔT.

[5] At a predetermined time t ₁ (for example, 60 seconds) from the start of operation, the heat exchanger temperature sensor 1 at the start of operation
Means for taking in the detected temperature Te as the outside air temperature To. [6] After a predetermined time t ₁ (for example, 60 seconds) from the start of operation,
The detected temperature Te of the heat exchanger temperature sensor 11 is output frequency F
Means for estimating the outside air temperature To.

[7] Control means for controlling operation using the taken-in or estimated outside air temperature To. [8] After a predetermined time t ₁ from the start of operation, means for calculating a difference between the detected temperature Te of the heat exchanger temperature sensor 11 estimates To ₁ and start of operation obtained by the functional means of [6] above.

[9] The obtained difference is equal to the set value α (for example, 2
℃) or more, the heat exchanger temperature sensor 11 at the start of operation
Means for taking in the detected temperature Te of FIG. [10] obtained difference is below the set value α when So taking the first estimate To ₁ as the outside air temperature To means.

Next, the operation of the above configuration will be described with reference to FIG. At the start of operation, first, a flag "flag" in the control unit is set to "0". And the heat exchanger temperature sensor 1
The first detected temperature Te is stored in the memory in the control unit as the outside air temperature To. This is at least the start of operation until a predetermined time t ₁ has elapsed, is continued.

When a predetermined time t ₁ has elapsed since the start of operation,
The detected temperature Te of the heat exchanger temperature sensor 11 is sequentially read, and the correction value f (F) corresponding to the output frequency F of the inverter circuit 41 is sequentially read.

Then, for the detected temperature Te read,
Read the correction value f (F) is added, the estimated value To ₁ of the outside air temperature is determined. To ₁ = Te + f (F) When the estimated value To ₁ is obtained, the estimated value To ₁ and the stored outside air temperature To (ie, the heat exchanger temperature sensor 1 at the start of operation)
1 (= To ₁ −To).

If this difference (absolute value) is equal to or greater than the set value α,
Based on the determination that the operation has not been stabilized yet, the already stored outside air temperature To is continuously valid as it is. When the difference is below the set value alpha, under the determination that the operation is stabilized, the estimate To ₁ is where it is first updated and stored as the outside air temperature To. Thereafter, the flag flag is set to “1”, and the estimated and updated outside air temperature To becomes effective.

The effect is the same as that of the first embodiment. In particular, the determination as to whether or not to take in the estimated value To ₁ as the outside temperature To is made based on two stages of the passage of time and the magnitude of the estimated value To _1. Therefore, the effect of improving the reliability as the outside air temperature To is added.

Next, a third embodiment of the present invention will be described. In this embodiment, in addition to the first and second embodiments, the outside air temperature To is estimated by taking into account the amount of refrigerant gas in the refrigeration cycle.

Here, as shown in FIG. 9, the outdoor unit A is provided with a current sensor 42, and the current sensor 42 supplies a current to the power supply line ACL between the outdoor control unit 40 and the inverter circuit 41. The value is detected, and the detection result (detection current Iin) is sent to the outdoor control unit 40.

The indoor control section 20 and the outdoor control section 40 have the following functional means. [1] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the solid arrow shown in FIG. 2, thereby forming a cooling cycle, and causing the outdoor heat exchanger 3 to function as a condenser and the indoor heat exchanger 5 to function as an evaporator. Means for performing a cooling operation or a dry operation (= weak cooling operation).

[2] The refrigerant discharged from the compressor 1 is caused to flow in the direction of the dashed arrow shown in FIG. 2 by switching the four-way valve 2, thereby forming a heating cycle and allowing the indoor heat exchanger 5 to operate as a condenser and outdoor heat exchanger. Means for causing the heater 3 to function as an evaporator and performing a heating operation.

[3] A means for switching the four-way valve 2 and performing a defrosting operation on the outdoor heat exchanger 3 when the temperature detected by the heat exchanger temperature sensor 11 becomes lower than a predetermined value, for example, 0 ° C. or lower during heating.

[4] During cooling and heating, the difference ΔT between the detected temperature Ta of the indoor temperature sensor 12 and the set temperature Ts of the remote controller.
Means for determining the output frequency (the operating frequency of the compressor 1) F of the inverter circuit 41 in accordance with the difference ΔT.

[5] At a predetermined time t ₁ (for example, 5 minutes) from the start of operation, the heat exchanger temperature sensor 1 at the start of operation
Means for taking in the detected temperature Te as To. [6] After a predetermined time t ₁ (for example, 5 minutes) from the start of operation,
Means for reading a first correction value f (F) corresponding to the output frequency F (and the outdoor fan rotation speed rps).

[7] After a predetermined time t ₁ (for example, 5 minutes) from the start of operation, based on the detection current Iin of the current sensor 42,
Means for reading the amount of refrigerant gas according to the output frequency F. [8] Means for reading the second correction value f (I) based on the refrigerant gas amount.

[9] The estimated value To ₁ of the outside air temperature is obtained based on the first correction value f (F), the second correction value f (I), and the detected temperature Te of the heat exchanger temperature sensor 11. means. [10] Means for updating and storing the estimated value To ₁ as To.

[11] Control means for controlling operation using the updated outside air temperature To. Next, the operation of the above configuration will be described with reference to FIG. When the start operation of the cooling operation is performed by the remote controller 22,
The detected temperature Te of the heat exchanger temperature sensor 11 is read and stored in the memory in the control unit as the outside air temperature To.
At the same time, a time count t is started.

Then, the compressor 1 is started, and the refrigerant discharged from the compressor 1 passes through the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, the indoor heat exchanger 5, and the four-way valve 2, and Returning to 1, a cooling cycle is formed. Thereby, the outdoor heat exchanger 3 functions as a condenser and the indoor heat exchanger 5 functions as an evaporator, and the room is cooled.

At the time of cooling, the detected temperature Ta of the indoor temperature sensor 12 is read, and the difference ΔT (= | Ta−Ts |) between the detected temperature Ta and the temperature Ts set by the remote controller 22 is obtained as the air conditioning load. The output frequency (the operating frequency of the compressor 1) F of the inverter circuit 41 is set to a value corresponding to the temperature difference ΔT, and the capacity of the compressor is controlled.

During operation, various controls are executed in accordance with the outside air temperature To stored in the memory, as in the first embodiment. After the time count t has reached the predetermined time t ₁ is
As the detection temperature Te of the heat exchanger temperature sensor 11 and the detection current Iin of the current sensor 42 are sequentially read, a correction value f corresponding to the output frequency F of the inverter circuit 41 is obtained.
(F) and f (I) are sequentially read.

The correction value f (F) is a function of the output frequency F as shown in FIG. 11, and is stored in advance in the ROM in the control unit as the correction value setting condition, as in the first embodiment.

The correction value f (I) is a function of the refrigerant gas amount as shown in FIG. 13, and the refrigerant gas amount has a correlation with the detection current Iin of the current sensor 42 as shown in FIG. . As shown in FIG. 12, when the refrigerant gas amount changes, the load acting on the compressor 1 changes, and the current value required for driving the compressor 1 (the detection current Iin of the current sensor 42) also changes.
The relationship between the refrigerant gas amount and the current Iin is based on the output frequency F
It varies depending on (F ₁ ~F _3). Then, as shown in FIG. 13, if f (I) is known, the refrigerant gas amount is determined. That is, if the refrigerant gas amount decreases, f (I) decreases. These correlations are stored in the ROM in the control unit in advance.

In order to avoid complication of the diagram, the relationship between the refrigerant gas amount and the current Iin is determined in three stages (F ₁ to F _1).
3 only), the relationship between the refrigerant gas amount and the current Iin is stored for all frequencies that may actually be operated. The correction value setting conditions shown in FIG. 12 and FIG. 13 are for cooling, and although not shown, they are of course prepared for heating.

[0067] sensed temperature Te is read, also, the correction value f (F), if f (I) is read out, the calculation of the following equation using both the estimated value To ₁ of the outside air temperature is determined. To ₁ = Te + f (F) + f (I) FIG. 14 shows this relationship. To ₁ is in a proportional relationship with Te. As the amount of refrigerant decreases, f (I) increases.

As described above, in this embodiment,
The temperature of the outdoor heat exchanger 3, the output frequency of the compressor 1, and
Since the outside air temperature is set based on the amount of the refrigerant gas, the outside air temperature can be detected while preventing the effect of the amount of the refrigerant gas besides having the same effect as in the first embodiment. Therefore,
Regardless of the amount of refrigerant charged in the refrigeration cycle at the time of installation, the accuracy of the estimation of the outside air temperature can be further improved. The present invention is not limited to the above embodiment, and various modifications can be made without changing the gist.

[0069]

As described above, according to the first and second aspects of the present invention, the outside air temperature is estimated from the temperature of the outdoor heat exchanger, so that the outside air temperature can be detected without requiring an outside air temperature sensor. This eliminates the need for consideration of mounting locations, such as when using an outside air temperature sensor, and eliminates adverse effects such as solar radiation, reducing the work load during installation and reducing costs while maintaining reliability. It is possible to provide an air conditioner capable of highly sensitive outside air temperature detection.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control circuit according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a refrigeration cycle of the embodiment.

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

FIG. 4 is a view showing a format of a correction value setting condition of the embodiment.

FIG. 5 is a diagram showing a proportional relationship between the heat exchanger temperature and the outside air temperature in the embodiment.

FIG. 6 is a diagram showing a relationship between a heat exchanger temperature and an estimated value according to the embodiment.

FIG. 7 is a diagram showing a change in outside air temperature obtained in the embodiment.

FIG. 8 is a flowchart for explaining the operation of the second embodiment of the present invention.

FIG. 9 is a block diagram of a control circuit according to a third embodiment of the present invention.

FIG. 10 is a flowchart for explaining the operation of the embodiment.

FIG. 11 is a diagram showing a proportional relationship between the heat exchanger temperature and an estimated value in which only the output frequency is considered in the embodiment.

FIG. 12 is a view showing the relationship between the drive current and the amount of refrigerant in the embodiment.

FIG. 13 is a view showing a relationship between the refrigerant gas amount and a second correction value in the embodiment.

FIG. 14 is a diagram showing a proportional relationship between a heat exchanger temperature and an estimated value in consideration of an output frequency and a refrigerant gas amount in the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Variable capacity compressor, 3 ... Outdoor heat exchanger, 5 ... Indoor heat exchanger, 11 ... Heat exchanger temperature sensor, 12 ... Indoor temperature sensor, 20 ... Indoor control part, 40 ... Outdoor control part, 41 ... Inverter Circuit, 42 ... Current sensor.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junsuke Shirakawa 336 Tatehara, Fuji-shi, Shizuoka Prefecture Inside the Toshiba Fuji Plant, Ltd. (72) Inventor Atsushi Nagasawa 336 Tatehara, Fuji City, Shizuoka Prefecture Higashi-Shiba Fuji Plant, Ltd. (72) Inventor Naoki Omura 336 Tatehara, Fuji-shi, Shizuoka Prefecture Inside the Toshiba Fuji Plant, Ltd. (72) Inventor Toshiyuki Uemura 336 Tatehara, Fuji City, Shizuoka Prefecture Inside the Toshiba Fuji Plant, Ltd. (72) Inventor Konemura 336 Tatehara, Fuji City, Shizuoka Prefecture Inside the Toshiba Fuji Plant (56) References JP-A-62-125244 (JP, A) JP-A-60-62543 (JP, A) JP-A-56-59152 (JP) , A) JP-A-54-129738 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24F 11/02 103 F24F 11/02 102 F24F 11/02

Claims (2)

(57) [Claims] 1. A refrigeration cycle comprising a variable capacity compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger, and an inverter for supplying drive power to the compressor.
In an air conditioner that controls the output frequency of the inverter according to the air conditioning load, a temperature sensor that detects the temperature of the outdoor heat exchanger and a temperature sensor that detects the temperature of the temperature sensor at the start of operation for a predetermined time from the start of operation. Means for taking in as air temperature, means for estimating the outside air temperature by correcting the detected temperature of the temperature sensor according to the output frequency after a predetermined time from the start of operation, and the estimated value and the temperature sensor at the start of operation. Means for obtaining a difference from the detected temperature, means for taking the detected temperature of the temperature sensor at the start of operation when the difference is equal to or more than a set value as an outside air temperature, An air conditioner comprising: means for taking a value as an outside air temperature; and control means for controlling operation using the taken outside air temperature. 2. A refrigeration cycle comprising a variable capacity compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger, and an inverter for supplying drive power to the compressor.
In an air conditioner that controls an output frequency of the inverter according to an air conditioning load, a temperature sensor that detects a temperature of the outdoor heat exchanger, a current detection unit that detects a drive current of the compressor, Means for correcting the detected temperature in accordance with the output frequency and the drive current to estimate an outside air temperature.