JP6576468B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner, and more particularly to control of a temperature blown out from an indoor unit.

  In a conventional air conditioner, for example, the temperature of the indoor space is adjusted using a refrigeration cycle including a compressor, a condenser, an expansion valve, an evaporator, and a blower. For example, in the cooling operation, the air in the indoor space is cooled by heat exchange between the refrigerant flowing through the evaporator and the air taken in by the blower.

In such an air conditioner, when it is desired to set the temperature of the indoor space to a predetermined temperature, the target value of the blowing temperature blown out from the indoor unit is set by the user, and the actual blowing temperature from the indoor unit is set. The target temperature is controlled.
Specifically, for example, attention is paid to the difference between the blow-out temperature from the indoor unit and the set temperature that is the target temperature. When the difference between the blowing temperature and the set temperature becomes small, the compressor frequency is lowered, and when the difference between the blowing temperature and the set temperature becomes large, the compressor frequency is increased. And the blowing temperature is adjusted.

  As another method for adjusting the blowout temperature, Patent Document 1 discloses that the blowout temperature is adjusted by adjusting the air volume of the fan of the outdoor unit according to the outside air temperature or by limiting the speed of increase of the compressor frequency. A method for suppressing a significant deviation from the set temperature is described.

Japanese Patent No. 5487171

  However, when the air conditioner is controlled by paying attention only to the difference between the blowing temperature and the set temperature as in the prior art, the responsiveness to temperature changes is poor. For example, if the cooling operation is performed when the suction temperature in the indoor unit is low, the blowout temperature is significantly lower than the set temperature, and so-called overshoot occurs, which impairs user comfort. was there.

  Moreover, in the method of patent document 1, it only adjusts the capability change speed of an apparatus, for example, when starting an air conditioner, time is required for blowing temperature to reach preset temperature. End up. For this reason, there is a risk of giving the user an impression that the cooling effect is low.

  The present invention has been made in view of the above problems in the prior art, and suppresses overshooting until the blowing temperature reaches the set temperature, and shortens the time until the blowing temperature reaches the set temperature. An object of the present invention is to provide an air conditioner that can be used.

The air conditioner of the present invention includes a refrigerant circuit that sequentially connects a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger with refrigerant piping to circulate the refrigerant, and heat exchange with the refrigerant by the indoor heat exchanger. An air conditioner including an air blower that takes in air , an outdoor heat exchanger pressure sensor that detects an outdoor heat exchanger pressure that is a pressure of a refrigerant flowing into the outdoor heat exchanger, and the outdoor heat exchanger An outdoor heat exchanger outlet temperature sensor that detects an outdoor heat exchanger outlet temperature that is the temperature of the refrigerant flowing out of the indoor heat exchanger, and an indoor heat exchanger that detects an indoor heat exchanger temperature that is the temperature of the refrigerant flowing into the indoor heat exchanger Temperature sensor, an indoor heat exchanger outlet temperature sensor that detects an indoor heat exchanger outlet temperature that is a temperature of the refrigerant flowing out of the indoor heat exchanger, and an intake temperature of air flowing into the indoor heat exchanger Sucking air Sensor and the calculated refrigerant circulation amount necessary in order to set the set temperature by a user the outlet temperature of the air in the indoor heat exchanger, said at compressor frequency that satisfies the calculated the amount of circulated refrigerant and a control unit for controlling to operate the compressor, the control device is determined based on the air volume of the blower, the amount of air passing through without touching the outdoor heat exchanger to the air volume And a storage unit for storing the refrigerant physical property information of the refrigerant, and a target evaporation temperature based on the suction temperature, the set temperature, and the bypass factor during cooling operation. Calculated based on the air flow rate, the intake air enthalpy, the saturated air enthalpy, and the bypass factor. And calculating the refrigerant circulation amount necessary to make the suction temperature the target outlet temperature based on the calculated evaporation capacity, the evaporator inlet enthalpy, and the evaporator outlet enthalpy, The compression frequency of the compressor that satisfies the calculated refrigerant circulation amount is calculated .

  As described above, according to the present invention, the refrigerant circulation amount for setting the suction temperature to the target blowing temperature is calculated, and the compressor frequency of the compressor is adjusted so as to satisfy the calculated refrigerant circulation amount. Thus, it is possible to suppress overshoot until the blowing temperature reaches the set temperature, and to shorten the time until the blowing temperature reaches the set temperature.

It is the schematic which shows an example of the circuit structure of the air conditioner which concerns on embodiment of this invention. It is a ph diagram which shows the refrigerating cycle in the air conditioner of FIG. It is a flowchart which shows an example of the flow of the compressor frequency control process of the compressor in the air conditioner of FIG. It is an air line figure which shows the state of the air in the evaporator in the air conditioner of FIG. It is the schematic explaining an example of the relationship between the compressor frequency by the compressor frequency control in the conventional air conditioner, and the blowing temperature. It is the schematic explaining the other example of the relationship between the compressor frequency by the compressor frequency control in the conventional air conditioner, and the blowing temperature. It is the schematic explaining an example of the relationship between the compressor frequency by the compressor frequency control in the air conditioner of FIG. 1, and blowing temperature. It is an air line figure which shows the state of the air in the indoor heat exchanger in the air conditioner of FIG. It is a ph diagram which shows the refrigerating cycle in the air conditioner of FIG.

  Hereinafter, an air conditioner according to an embodiment of the present invention will be described.

[Circuit configuration of air conditioner]
FIG. 1 is a schematic diagram illustrating an example of a circuit configuration of an air conditioner according to an embodiment of the present invention.
As shown in FIG. 1, an air conditioner 1 includes a compressor 2, an outdoor heat exchanger 3, an expansion valve 4, an indoor heat exchanger 5, a fan 6 as a blower, a motor 7, a control device 10, and an outdoor heat exchanger. A pressure sensor 11, an outdoor heat exchanger outlet temperature sensor 12, an indoor heat exchanger temperature sensor 13, an indoor heat exchanger outlet temperature sensor 14, and an intake air state sensor 15 are provided. The compressor 2, the outdoor heat exchanger 3, the expansion valve 4, and the indoor heat exchanger 5 are connected in an annular shape by a refrigerant pipe to form a refrigerant circuit in which the refrigerant circulates.
As the refrigerant circulating in the refrigerant circuit, for example, a single refrigerant such as R-22, a mixed refrigerant such as R-410A, or a natural refrigerant such as CO ₂ can be used.
In the following description, a circuit configuration in the case of performing the cooling operation for cooling the air in the indoor space will be described as an example.

The compressor 2 sucks a low-temperature and low-pressure refrigerant, compresses the refrigerant, and discharges it in a high-temperature and high-pressure gas refrigerant state.
As the compressor 2, for example, an inverter compressor or the like capable of controlling a displacement volume that is a refrigerant delivery amount per unit time by arbitrarily changing a compressor frequency that is a driving frequency can be used. .

  The compressor 2 is not limited to this, and for example, a compressor having a constant driving frequency may be used. In the case of using such a compressor, for example, the refrigerant delivery amount is adjusted by changing the suction pressure of the refrigerant or by providing a bypass circuit (not shown) in the refrigerant circuit, as in the case of changing the drive frequency. be able to.

The outdoor heat exchanger 3 performs heat exchange between the high-temperature and high-pressure gas refrigerant and the external fluid. Specifically, the outdoor heat exchanger 3 functions as a condenser that radiates the heat of the refrigerant to the fluid during the cooling operation and condenses the refrigerant into a high-pressure liquid refrigerant. The external fluid at this time may be, for example, a gas such as air or a liquid such as water.
Note that, here, the case where the cooling operation is performed is described as an example, and in the following, the “outdoor heat exchanger 3” will be referred to as “condenser 3” as appropriate.

  The expansion valve 4 has a function of decompressing and expanding the high-pressure liquid refrigerant flowing in the refrigerant circuit into a low-pressure gas-liquid two-phase refrigerant. The expansion valve 4 may be, for example, a valve capable of controlling the opening degree, such as an electronic expansion valve, or a capillary tube.

The indoor heat exchanger 5 exchanges heat between the low-pressure gas-liquid two-phase refrigerant and the air in the indoor space (hereinafter referred to as “indoor air” as appropriate). Specifically, the indoor heat exchanger 5 functions as an evaporator that evaporates the refrigerant into a low-pressure gas refrigerant during the cooling operation and cools the indoor air by the heat of vaporization at that time.
Note that, here, the case where the cooling operation is performed is described as an example, and in the following, the “indoor heat exchanger 5” will be referred to as “evaporator 5” as appropriate.

The fan 6 is provided in the vicinity of the evaporator 5. The fan 6 is driven by a motor 7 to supply air for exchanging heat with the evaporator 5 to the evaporator 5. Further, the fan 6 supplies information indicating the amount of air blown to the evaporator 5 to the control device 10 described later.
As the fan 6, for example, various fans such as a sirocco fan and a plug fan can be used. In addition, as a method for taking in air, for example, a pushing method or a pulling method may be used.

The outdoor heat exchanger pressure sensor 11 is provided in the refrigerant pipe on the refrigerant inflow side of the outdoor heat exchanger 3 and detects an outdoor heat exchanger pressure that is the pressure of the refrigerant flowing into the outdoor heat exchanger 3. Information indicating the detected outdoor heat exchanger pressure is supplied to the control device 10 described later.
Here, since the case where the cooling operation is performed is described as an example, the “outdoor heat exchanger pressure sensor 11” will be referred to as the “condenser pressure sensor 11” and the “outdoor heat exchanger pressure” will be referred to below. This will be described as “condenser pressure”.

The outdoor heat exchanger outlet temperature sensor 12 is provided in the refrigerant pipe on the refrigerant outflow side of the outdoor heat exchanger 3 and detects an outdoor heat exchanger outlet temperature that is the temperature of the refrigerant flowing out of the outdoor heat exchanger 3. Information indicating the detected outdoor heat exchanger outlet temperature is supplied to the control device 10.
Here, since the case where the cooling operation is performed is described as an example, the “outdoor heat exchanger outlet temperature sensor 12” is hereinafter referred to as “condenser outlet temperature sensor 12” and “outdoor heat exchanger outlet”. “Temperature” will be referred to as “condenser outlet temperature”.

The indoor heat exchanger temperature sensor 13 is provided in the refrigerant pipe on the refrigerant inflow side of the indoor heat exchanger 5 and detects the indoor heat exchanger temperature that is the temperature of the refrigerant flowing into the indoor heat exchanger 5. Information indicating the detected indoor heat exchanger temperature is supplied to the control device 10.
Here, since the case where the cooling operation is performed is described as an example, hereinafter, “indoor heat exchanger temperature sensor 13” is referred to as “evaporator temperature sensor 13”, and “indoor heat exchanger temperature” is referred to as “indoor heat exchanger temperature”. This will be described as “evaporator temperature”.

The indoor heat exchanger outlet temperature sensor 14 is provided in the refrigerant pipe on the refrigerant outflow side of the indoor heat exchanger 5, and detects the indoor heat exchanger outlet temperature that is the temperature of the refrigerant flowing out of the indoor heat exchanger 5. Information indicating the detected evaporator outlet temperature is supplied to the control device 10.
In addition, since the case where the cooling operation is performed is described as an example here, the “indoor heat exchanger outlet temperature sensor 14” is hereinafter referred to as “evaporator outlet temperature sensor 14” and “indoor heat exchanger outlet”. “Temperature” will be referred to as “evaporator outlet temperature”.

The intake air state sensor 15 is provided in the vicinity of the indoor heat exchanger 5 and detects the dry bulb temperature and wet bulb temperature of the air flowing into the indoor heat exchanger 5. Information indicating the detected dry bulb temperature and wet bulb temperature is supplied to the control device 10.
When the wet bulb temperature cannot be measured, the relative humidity can be detected, and the wet bulb temperature may be calculated by the control device 10 based on the air physical properties described later stored in the control device 10.

  The control device 10 is configured by, for example, hardware such as a microcomputer, software executed on an arithmetic device such as a CPU (Central Processing Unit), a circuit device that realizes a control function described later, and the like. To control. For example, the control device 10 sets the driving frequency of the compressor 2 and the ON / OFF of the fan 6 based on the operation information of the air conditioner 1 based on information received from various detection means and the operation content instructed by the user. The rotational speed to be included, the opening degree of the expansion valve 4 and the like are controlled.

The control device 10 has a ROM (Read Only Memory) (not shown) as a storage unit, and information for performing various processes in the present embodiment is stored in advance in the ROM.
Various types of information stored in the ROM are, for example, air physical property information, refrigerant physical property information, capacity calculation formulas, and bypass factor information.

The air physical property information is information indicating the physical properties of the air that exchanges heat with the refrigerant in the evaporator 5. The air physical property information is, for example, a table in which air temperature, humidity, density, enthalpy, and the like are associated with each other, and the density and enthalpy are determined according to temperature and humidity.
If values of density and enthalpy corresponding to air temperature and humidity that are not listed in the air physical property information table are required, these values can be obtained by interpolation using values in the table, for example. it can.

The refrigerant physical property information is information indicating the physical properties of the refrigerant flowing in the refrigerant circuit. The refrigerant physical property information is, for example, a table in which the temperature, pressure, density, enthalpy, and the like of the refrigerant are associated with each other, and the density and enthalpy are determined according to the temperature and pressure.
If values of density and enthalpy corresponding to the temperature and pressure of the refrigerant not listed in the refrigerant property information table are required, these values can be obtained by interpolating using the values in the table, for example. it can.

The capability calculation formula is a calculation formula for calculating a value necessary for performing various processes in the present embodiment. A specific stored arithmetic expression will be described later.
The bypass factor information is information indicating the ratio of the amount of air that has passed through the evaporator 5 without touching the evaporator 5 with respect to the amount of air supplied by the fan 6 when the air passes through the evaporator 5. The bypass factor BF is determined according to the amount of air blown into the evaporator 5 by the fan 6. For example, the bypass factor BF becomes a larger value as the air flow rate is larger.

  Based on the pressure information and temperature information supplied from the various sensors 11 to 15 and various information such as the above-described refrigerant physical property information, the control device 10 requires the refrigerant circulation amount Gr to reach the set temperature. The compressor frequency that satisfies the above is calculated. Then, the control device 10 controls the compressor 2 based on the calculated compressor frequency.

FIG. 2 is a ph diagram showing a refrigeration cycle in the air conditioner of FIG. 1.
The refrigerant state at point a shown in FIG. 2 indicates the refrigerant state at point a shown in FIG. Similarly, the refrigerant states at points b to d shown in FIG. 2 indicate the refrigerant states at points b to d shown in FIG. 1, respectively.

The condenser pressure Pcm, which is the pressure of the refrigerant at the point b, is detected by the condenser pressure sensor 11.
The control device 10 can obtain the temperature associated with the condenser pressure Pcm as the condenser temperature by referring to the refrigerant physical property information table stored in the ROM based on the condenser pressure Pcm.

The condenser outlet temperature, which is the refrigerant temperature at point c, is detected by the condenser outlet temperature sensor 12.
The control device 10 can calculate the degree of supercooling SCm based on the condenser outlet temperature and the condenser temperature obtained as described above.

The evaporator temperature Te, which is the temperature of the refrigerant at the point d, is detected by the evaporator temperature sensor 13.
The control device 10 can obtain the pressure associated with the evaporator temperature Te as the evaporator pressure Pe by referring to the refrigerant property information table based on the evaporator temperature Te.

The evaporator outlet temperature, which is the refrigerant temperature at point a, is detected by the evaporator outlet temperature sensor 14.
The control device 10 can calculate the superheat degree SHm based on the evaporator outlet temperature and the evaporator temperature Te calculated as described above.

[Air conditioner operation]
Next, operation | movement of the air conditioner 1 which has the said structure is demonstrated. In this example, the flow of the refrigerant in the cooling operation mode will be described.

First, the low-temperature and low-pressure refrigerant is compressed by the compressor 2 and is discharged from the compressor 2 as a high-temperature and high-pressure gas refrigerant.
The high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the condenser 3, condenses while dissipating heat by exchanging heat with outdoor air, and flows out from the condenser 3 as a high-pressure liquid refrigerant in a supercooled state. To do.

The high-pressure liquid refrigerant flowing out of the condenser 3 is expanded and depressurized by the expansion valve 4 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant and flows into the evaporator 5.
The low-temperature and low-pressure gas-liquid two-phase refrigerant that has flowed into the evaporator 5 exchanges heat with the room air, absorbs heat and evaporates, thereby cooling the room air and flows out of the evaporator 5 as a low-temperature and low-pressure gas refrigerant.
The low-temperature and low-pressure gas refrigerant flowing out of the evaporator 5 is sucked into the compressor 2.

[Compressor frequency control]
Next, the compressor frequency control of the compressor 2 in the air conditioner 1 will be described.
In the air conditioner 1 according to the present embodiment, when a set temperature, which is a target value of the temperature of air blown from the indoor unit, is set by the user, the blowing temperature from the evaporator 5 provided in the indoor unit is set. The refrigerant circulation amount necessary to quickly reach the set temperature is calculated. Then, the compressor frequency satisfying the obtained refrigerant circulation amount is calculated, and the compressor frequency of the compressor 2 is adjusted to the obtained compressor frequency.

FIG. 3 is a flowchart showing an example of the flow of the compressor frequency control process of the compressor 2 in the air conditioner 1 of FIG.
FIG. 4 is an air diagram showing the state of air in the evaporator 5 in the air conditioner 1 of FIG.
Here, it is assumed that the compressor frequency control of the compressor 2 is continuously performed, and the process of the flowchart of FIG. 3 is cyclically repeated. For example, the process shown in FIG. 3 is repeated every predetermined time.

First, in step S <b> 1, the control device 10 calculates a target evaporation temperature (hereinafter, appropriately referred to as “target evaporation temperature”) Tem in the evaporator 5. This target evaporation temperature Tem is a suction temperature at point A shown in FIG. 4 and a target blowing temperature that is a set temperature set by the user at point B (hereinafter referred to as “target blowing temperature” as appropriate). The temperature at point C on the saturation curve on extension is shown.
The target evaporation temperature Tem can be calculated based on the equation (1), which is an arithmetic expression stored in the ROM, using the bypass factor BF determined from the suction temperature Ti, the set temperature To, and the air flow rate Ga.
[Equation 1]
Tem = (To-Ti × BF) / (1-BF) (1)

The suction temperature Ti is the temperature of air exchanged with the refrigerant in the evaporator 5, and can be obtained based on information indicating the dry bulb temperature supplied from the suction air state sensor 15.
The set temperature To is a target blowing temperature set by the user.
The bypass factor BF is a value determined based on the air flow rate Ga of the fan 6, and is obtained by referring to the bypass factor information stored in the ROM based on the information indicating the air flow rate Ga supplied from the fan 6. Can do.

Next, in step S <b> 2, the control device 10 calculates the evaporation capacity Qe necessary for setting the suction temperature to the target blowing temperature.
The evaporation capacity Qe can be calculated based on Expression (2), which is an arithmetic expression stored in the ROM, using the blowing amount Ga, the suction air enthalpy hai, the saturated air enthalpy hae, and the bypass factor BF.
[Equation 2]
Qe = Ga * (hae-hai) * (1-BF) (2)

The suction air enthalpy hai indicates the enthalpy of the air sucked by the evaporator 5 and can be obtained by referring to a table of air property information stored in the ROM based on the suction temperature Ti.
The saturated air enthalpy hae indicates the enthalpy of saturated air in the evaporator 5 and can be obtained by referring to a table of air property information based on the target evaporation temperature Tem calculated in step S1.

Next, in step S <b> 3, the control device 10 calculates the refrigerant circulation amount Gr when the suction temperature is set as the target outlet temperature.
The refrigerant circulation amount Gr can be calculated based on the equation (3), which is an arithmetic expression stored in the ROM, using the evaporation capacity Qe, the evaporator inlet enthalpy hr, and the evaporator outlet enthalpy hro calculated in step S2. .
[Equation 3]
Gr = Qe / (hro-hri) (3)

Note that the evaporator inlet enthalpy hr indicates the enthalpy of the refrigerant flowing into the evaporator 5. The evaporator inlet enthalpy hr is a table of refrigerant physical property information stored in the ROM based on the condenser pressure Pcm detected by the condenser pressure sensor 11 and the condenser outlet temperature detected by the condenser outlet temperature sensor 12. Can be calculated with reference to FIG.
The evaporator outlet enthalpy hro indicates the enthalpy of the refrigerant flowing out of the evaporator 5. The evaporator outlet enthalpy hro is calculated based on the evaporator temperature Pe detected by the evaporator temperature sensor 13 and the refrigerant physical property information table, and the evaporator outlet detected by the evaporator outlet temperature sensor 14. Based on the temperature, it can be calculated with reference to the refrigerant property information table.

Here, the refrigerant circulation amount Gr can also be calculated based on the design specifications of the compressor 2.
The refrigerant circulation amount Gr based on the design specifications of the compressor 2 is an equation (4) that is an arithmetic expression stored in the ROM using the displacement volume V of the compressor 2 and the density ρ of the refrigerant compressed by the compressor 2. Can be calculated based on
[Equation 4]
Gr = V × ρ (4)

The density ρ of the refrigerant can be acquired by referring to a table of refrigerant physical property information, and specifically, is a density associated with the evaporator pressure Pe.
The displacement volume V is the amount of refrigerant discharged from the compressor 2 per unit time. For example, when the compressor 2 is a reciprocating compressor, the number of cylinders, the cylinder volume, and the rotational speed, which are design specifications, are determined. Determined by product. Information indicating the displacement volume V is stored in advance in the ROM of the control device 10.

  Further, since the displacement volume V of the compressor 2 is determined according to the rotational speed, it can be changed by changing the compressor frequency proportional to the rotational speed. Therefore, the refrigerant circulation amount Gr can be adjusted to a predetermined amount by adjusting the compressor frequency of the compressor 2.

Therefore, in step S4, the control device 10 calculates and adjusts the compressor frequency of the compressor 2 so that the refrigerant circulation amount Gr becomes the refrigerant circulation amount Gr calculated in step S3.
Thereby, in the air conditioner 1 by this Embodiment, the blowing temperature from the evaporator 5 can be brought close to preset temperature, without overshooting.

  As described above, in the present embodiment, the refrigerant circulation amount Gr for setting the air suction temperature in the evaporator 5 to be the target outlet temperature is calculated, and the compressor 2 is configured so as to satisfy the calculated refrigerant circulation amount Gr. Adjust the compressor frequency. Therefore, it is possible to suppress overshoot until the blowing temperature reaches the set temperature.

[About arrival time]
Here, the arrival time until the blowing temperature reaches the set temperature will be considered.
FIG. 5 is a schematic diagram for explaining an example of the relationship between the compressor frequency and the blowing temperature by the compressor frequency control in the conventional air conditioner. FIG. 6 is a schematic diagram for explaining another example of the relationship between the compressor frequency and the blowing temperature by the compressor frequency control in the conventional air conditioner.
FIG. 7 is a schematic diagram illustrating an example of the relationship between the compressor frequency and the blowing temperature by the compressor frequency control in the air conditioner of FIG.

As shown in FIG. 5, conventionally, attention is paid to the temperature difference between the blowing temperature and the set temperature, and when the time during which this temperature difference occurs exceeds a preset temperature difference time t, the compressor frequency is set. Change. For example, when the time when the blowing temperature is lower than the set temperature exceeds the temperature difference time t, the compressor frequency is decreased. Further, when the time during which the blowing temperature is higher than the set temperature exceeds the temperature difference time t, the compressor frequency is increased.
By repeatedly changing the compressor frequency in this way, the blowout temperature gradually approaches the set temperature while the overshoot amount is reduced. And finally, after the start of the operation time T ₁ of the compressor, outlet temperature stabilizes reaches the set temperature.

By the way, in the case where the compressor frequency is repeatedly changed, if the increase speed of the compressor frequency is increased, the speed at which the blowing temperature is brought close to the set temperature can be increased. However, in this case, since the blowing temperature rapidly rises or falls in a short time, the amount of overshoot that occurs when the blowing temperature exceeds or falls below the set temperature increases.
Therefore, in order to solve such a problem, as shown in FIG. 6, a method has been proposed in which the increase rate of the compressor frequency is made slower than that in the past to reduce the amount of overshoot of the blowing temperature.
In this case, the speed at which the blowing temperature is brought close to the set temperature is slower than the conventional one, but the temperature difference between the blowing temperature and the set temperature at the temperature difference time t can be reduced. Therefore, the amount of overshoot can be suppressed, and the time until the blowing temperature reaches the set temperature and stabilizes can be shortened to a time T ₂ that is shorter than the time T ₁ described above.
However, even in this case, it is difficult to make the blowing temperature reach the set temperature without overshooting.

On the other hand, in this embodiment, as shown in FIG. 7, by setting the compressor frequency by the above-described method, the blowout temperature can reach the set temperature and be stabilized without overshooting. . At this time, the time from the start of operation of the compressor 2 until the blowing temperature reaches the set temperature and stabilizes can be shortened to a time T ₃ shorter than the above-described times T ₁ and T ₂ .
Thus, in this Embodiment, time until blowing temperature reaches | attains setting time can be shortened more, without restrict | limiting the increase speed of a compressor frequency.

  In the above example, the compressor frequency adjustment process for the air conditioner 1 capable of performing the cooling operation has been described. However, the same process is performed for the air conditioner capable of performing the heating operation. Applicable.

FIG. 8 is an air diagram showing the state of air in the indoor heat exchanger 5 in the air conditioner 1 of FIG.
FIG. 9 is a ph diagram showing a refrigeration cycle in the air conditioner 1 of FIG. 1.
When performing the heating operation, the refrigerant suction side and the discharge side of the compressor 2 in the air conditioner 1 shown in FIG. 1 are switched, the indoor heat exchanger 5 functions as a condenser, and the outdoor heat exchanger 3 A refrigerant circuit is formed to function as an evaporator.

The control apparatus 10 calculates the target condensation temperature Tcm in the indoor heat exchanger 5 functioning as a condenser based on the equation (5), similarly to the above-described target evaporation temperature.
[Equation 5]
Tcm = (To-Ti × BF) / (1-BF) (5)

Next, the control device 10 calculates the condensing capacity Qc necessary for setting the suction temperature to the target blowing temperature To based on the equation (6).
[Equation 6]
Qc = Ga * Cp * (Tc-Ti) * (1-BF)
≒ Ga * (Tc-Ti) * (1-BF) (6)
Here, Cp is the air low pressure specific heat and can be omitted because it does not affect the calculation result in the use environment of the air conditioner 1.

Next, the control device 10 uses the calculated condensing capacity Qc, the condenser inlet enthalpy hri ', and the condenser outlet enthalpy hro' to calculate the refrigerant circulation amount Gr when the suction temperature Ti is set to the target outlet temperature To. Calculate based on (7).
[Equation 7]
Gr = Qc / (hro'-hri ') (7)

Then, similarly to the cooling operation, the control device 10 controls the compressor so that the refrigerant circulation amount Gr calculated based on the above-described equation (4) becomes the refrigerant circulation amount Gr calculated based on the equation (7). 2 compression frequency is calculated and adjusted.
Thereby, also in the air conditioner capable of performing the heating operation, it is possible to suppress overshoot until the blowing temperature from the indoor heat exchanger 5 reaches the set temperature.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments of the present invention, and various modifications and applications are possible without departing from the scope of the present invention. It is.
For example, the configuration of the air conditioner 1 is not limited to the configuration illustrated in FIG. 1, and may include an accumulator for protecting the compressor 2 or an oil separator for recovering refrigeration oil. . Further, for example, a refrigerant flow switching device that switches between a cooling operation and a heating operation by switching the direction in which the refrigerant flows may be provided in the air conditioner.

  DESCRIPTION OF SYMBOLS 1 Air conditioner, 2 Compressor, 3 Outdoor heat exchanger, 4 Expansion valve, 5 Indoor heat exchanger, 6 Fan, 7 Motor, 10 Control apparatus, 11 Outdoor heat exchanger pressure sensor, 12 Outdoor heat exchanger exit temperature Sensor, 13 indoor heat exchanger temperature sensor, 14 indoor heat exchanger outlet temperature sensor, 15 intake air condition sensor.

Claims (2)

A refrigerant circuit for circulating a refrigerant by sequentially connecting a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger with a refrigerant pipe;
An air conditioner comprising a blower that takes in air to exchange heat with the refrigerant in the indoor heat exchanger,
An outdoor heat exchanger pressure sensor that detects an outdoor heat exchanger pressure that is a pressure of a refrigerant flowing into the outdoor heat exchanger;
An outdoor heat exchanger outlet temperature sensor for detecting an outdoor heat exchanger outlet temperature which is a temperature of a refrigerant flowing out of the outdoor heat exchanger;
An indoor heat exchanger temperature sensor that detects an indoor heat exchanger temperature that is a temperature of a refrigerant flowing into the indoor heat exchanger;
An indoor heat exchanger outlet temperature sensor for detecting an indoor heat exchanger outlet temperature which is a temperature of a refrigerant flowing out of the indoor heat exchanger;
A suction air condition sensor for detecting a suction temperature of air flowing into the indoor heat exchanger;
A refrigerant circulation amount necessary for setting the air blowing temperature in the indoor heat exchanger to a set temperature set by a user is calculated, and the compressor is operated at a compressor frequency satisfying the calculated refrigerant circulation amount. comprising a <br/> a control device for controlling to operate,
The controller is
A storage unit that stores a bypass factor that is determined based on the amount of air blown from the blower and that passes through the outdoor air heat exchanger without touching the outdoor heat exchanger, and refrigerant physical property information of the refrigerant Have
During cooling operation, a target evaporation temperature is calculated based on the suction temperature, the set temperature, and the bypass factor,
Based on the blast volume, suction air enthalpy, saturated air enthalpy, and the bypass factor, calculate the evaporation capacity necessary to make the suction temperature a target blow temperature,
Based on the calculated evaporation capacity, the evaporator inlet enthalpy, and the evaporator outlet enthalpy, the refrigerant circulation amount required to make the suction temperature the target outlet temperature is calculated,
An air conditioner that calculates a compression frequency of the compressor that satisfies the calculated refrigerant circulation amount . The control device includes:
Based on the suction temperature, calculate the suction air enthalpy,
Calculate the saturated air enthalpy based on the evaporation temperature,
Based on the condenser pressure which is the outdoor heat exchanger pressure, the condenser outlet temperature which is the outdoor heat exchanger outlet temperature, and the refrigerant physical property information, the evaporator inlet enthalpy is calculated,
Based on the evaporator pressure that is the indoor heat exchanger temperature and the evaporator pressure obtained from the refrigerant physical property information, the evaporator outlet temperature that is the indoor heat exchanger outlet temperature, and the refrigerant physical property information, the evaporator the air conditioner according to claim 1 for calculating the outlet enthalpy.

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