JP5366768B2 - Air conditioner outdoor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an outdoor unit of an air conditioner, which elongates a heating operation time while suppressing blast noise by an outdoor fan. <P>SOLUTION: The outdoor fan 5 generates the airflow passing through an outdoor heat exchanger 4. A temperature sensor 6 measures the temperature of the outdoor heat exchanger 4. A control section 7 controls the rotational frequency of the outdoor fan 5 based on the outdoor heat exchanger temperature and a defrosting entry temperature (DIN) for starting a defrosting operation, and in a heating operation, it controls the rotational frequency of the outdoor fan 5 to an initial rotational frequency in starting the heating operation, and then reduces the rotational frequency in stages to a rotational frequency obtained by subtracting a prescribed rotational frequency (X) from the initial rotational frequency based on the outdoor heat exchanger temperature and the defrosting entry temperature. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an outdoor unit of an air conditioner, and more particularly to an outdoor unit that controls the rotational speed of an outdoor fan during heating operation.

  An outdoor unit of an air conditioner includes an outdoor heat exchanger and an outdoor fan. If frost formation on the outdoor heat exchanger progresses during heating, the frost becomes ventilation resistance and the performance of the air conditioner decreases. In order to prevent a decrease in performance, control is performed to keep the rotational speed of the outdoor fan constant or to increase the rotational speed, but if the outdoor fan is maintained at a constant rotational speed with a large ventilation resistance, The blowing sound of the outdoor fan may increase and give the user discomfort.

  As a countermeasure against such a problem, during the heating operation, when frost formation on the outdoor heat exchanger is detected or estimated, frost fan control for reducing the rotation speed of the outdoor fan is performed before the defrost operation. When the fan operation during frost formation is executed and the defrost operation start condition is satisfied, the outdoor fan can be blown without reducing the operation efficiency by starting the defrost operation when the defrost operation start condition is satisfied. An outdoor unit that suppresses sound is disclosed (for example, see Patent Document 1).

JP 2009-58222 A

  In patent document 1, when the fan control at the time of frost formation is performed, if the amount of decrease in the rotational speed of the outdoor fan is large, the temperature of the outdoor heat exchanger decreases rapidly, so that the frost formation may be accelerated. . If the progress of frosting is accelerated, the start of the defrosting operation is accelerated, so that the heating operation time is shortened and the efficiency of the heating operation is lowered.

  Then, this invention aims at providing the outdoor unit of the air conditioner which can lengthen heating operation time, suppressing the ventilation sound of an outdoor fan by reducing the rotation speed of an outdoor fan in steps. To do.

A first aspect of an outdoor unit of an air conditioner according to the present invention includes an outdoor heat exchanger (4), an outdoor fan (5) that generates a flow of air passing through the outdoor heat exchanger (4), The outdoor fan includes a temperature sensor (6) for measuring an outdoor heat exchanger temperature of the outdoor heat exchanger (4), the outdoor heat exchanger temperature, and a defrosting entry temperature (DIN) for starting a defrosting operation. A controller (7) for controlling the rotational speed of (5), and before the defrosting operation during heating, the controller (7) determines the rotational speed of the outdoor fan (5) and starts the heating operation. Sometimes after setting the initial rotation speed, the rotation speed is decreased stepwise based on the outdoor heat exchanger temperature and the defrost entry temperature until the rotation speed is obtained by subtracting the predetermined rotation speed (X) from the initial rotation speed. Control is performed.

And in the said rotation speed control, the said control part (7) is triggered by the said outdoor heat exchanger temperature falling below the value which added the positive 1st predetermined value ((alpha)) to the said defrost entry temperature. The rotational speed of the outdoor fan (5) was lowered , and the outdoor heat exchanger temperature was further added with a positive second predetermined value (β) smaller than the first predetermined value to the defrost entry temperature. triggered by a decrease to a value below also characterized Rukoto reduce the rotational speed of the outdoor fan (5).

The 2nd aspect of the outdoor unit of the air conditioner which concerns on this invention is an outdoor unit of the air conditioner which concerns on a 1st aspect, Comprising: In the said rotation speed control, the said control part (7) is the said outdoor heat exchange. The outdoor fan (in response to a further decrease in the chamber temperature to a value obtained by adding a positive third predetermined value (γ) smaller than the second predetermined value (β) to the defrost entry temperature, 5) lowering the rotational speed, characterized in Rukoto.
The 3rd aspect of the outdoor unit of the air conditioner which concerns on this invention is an outdoor unit of the air conditioner which concerns on a 1st aspect or a 2nd aspect, Comprising: The said outdoor heat exchanger temperature is the said defrost entry temperature. The defrosting operation is started after waiting for the following.

According to a first state like the outdoor unit of an air conditioner according to the present invention, the control unit by lowering the rotational speed of the outdoor fan in stages, lengthening the heating operation time while suppressing the blowing noise of outdoor fan It becomes possible to do.

According to a second aspect of the outdoor unit of an air conditioner according to the present invention, the control unit by lowering the rotational speed of the outdoor fan in stages, lengthening the heating operation time while suppressing the blowing noise of outdoor fan It becomes possible.

According to the 3rd aspect of the outdoor unit of the air conditioner which concerns on this invention, it becomes possible to start a defrost operation, when the outdoor heat exchanger temperature becomes below a defrost entry temperature.

It is the figure which showed an example of the notional structure of an air conditioner. It is the figure which showed an example of the notional structure of a control part. It is a flowchart which shows an example of the control in a control part.

<Embodiment>
FIG. 1 is a diagram illustrating an example of a conceptual configuration of the air conditioner 1. As shown in FIG. 1, the air conditioner 1 includes an outdoor unit 2 and an indoor unit 3. The outdoor unit 2 includes an outdoor heat exchanger 4, an outdoor fan 5, a temperature sensor 6, and a control unit 7. The outdoor fan 5 generates a flow of air passing through the outdoor heat exchanger 4, and the temperature sensor 6 is also referred to as an outdoor heat exchanger temperature (hereinafter referred to as “external heat exchange temperature”) that is the temperature of the outdoor heat exchanger 4. Measuring).

  The outdoor unit 2 includes a compressor 8 and an expansion valve 9, and the indoor unit 3 includes an indoor heat exchanger 10. The outdoor unit 2 and the indoor unit 3 have a refrigerant circuit, and the refrigerant in the refrigerant circuit circulates via the outdoor heat exchanger 4, the compressor 8, the indoor heat exchanger 10, and the expansion valve 9.

  FIG. 2 is a diagram illustrating an example of a conceptual configuration of the control unit 7. As shown in FIG. 2, the control unit 7 is electrically connected between the outdoor fan 5 and the temperature sensor 6, and removes the external heat exchange temperature of the outdoor heat exchanger 4 and the defrosting operation. The rotational speed of the outdoor fan 5 is controlled by the frost entry temperature.

  FIG. 3 is a flowchart illustrating an example of control in the control unit 7. The controller 7 according to the embodiment of the present invention sets the rotation speed of the outdoor fan 5 to the initial rotation speed at the start of the heating operation, and then based on the external heat exchange temperature and the defrost entry temperature (DIN) The present invention is characterized in that the rotational speed control is performed in a stepwise manner until the rotational speed is obtained by subtracting the predetermined rotational speed (X) from the initial rotational speed.

  As shown in FIG. 3, when the heating operation starts, the process waits until the compressor 8 starts operating in step S <b> 1. When the compressor 8 starts operating, the outdoor fan 5 is operated in step S2. At this time, the rotational speed of the outdoor fan 5 is an initial value (initial rotational speed).

  Thereafter, the timer (T1) is set and started in step S3, and the process waits until the timer (T1) is timed up in step S4. The predetermined time (T1) after the start of the heating operation does not cause frost formation on the outdoor heat exchanger 4, and is set to prevent erroneous detection of frost formation.

  When the timer (T1) expires, the external heat exchange temperature of the outdoor heat exchanger 4 measured by the temperature sensor 6 is read in step S5. In addition, since the possibility of frost formation is low if the difference between the outside air temperature and the outside heat exchange temperature is equal to or less than a predetermined value, the present flowchart may be omitted.

  After measuring the external heat exchange temperature, in step S6, it is determined whether or not the measured external heat exchange temperature is equal to or less than a value (temperature) obtained by adding a positive predetermined value (α) to the defrost entry temperature (DIN). . That is, it is determined whether or not a value obtained by subtracting the defrost entry temperature from the external heat exchange temperature (first temperature difference value) is equal to or less than a predetermined positive value (α). Here, the defrost entry temperature (DIN) is expressed as a function of the operating frequency (Hz) of the compressor 8 and the outside air temperature (° C.), and varies depending on each parameter value.

  If "YES" is determined in the step S6, the rotational speed of the outdoor fan 5 is decreased in the step S7 (first control). The rotational speed of the outdoor fan 5 set in step S7 is a value (rotational speed) obtained by subtracting one third of the predetermined rotational speed (X) from the initial rotational speed.

  After the rotational speed of the outdoor fan 5 is decreased in step S7, whether or not the newly measured external heat exchange temperature is equal to or less than a value obtained by adding a positive predetermined value (β) to the new defrost entry temperature in step S8. Judge whether or not. That is, it is determined whether or not a value (second temperature difference value) obtained by subtracting the new defrost entry temperature from the newly measured external heat exchange temperature is equal to or less than a predetermined positive value (β). Here, the positive predetermined value (β) is a value smaller than the positive predetermined value (α).

  If "YES" is determined in the step S8, the rotational speed of the outdoor fan 5 is decreased in the step S9 (second control). The rotational speed of the outdoor fan 5 set in step S9 is a value obtained by subtracting two-thirds of the predetermined rotational speed (X) from the initial rotational speed.

  After reducing the rotational speed of the outdoor fan 5 in step S9, in step S10, the newly measured external heat exchange temperature is not more than a value obtained by adding a positive predetermined value (γ) to the new defrost entry temperature. Judge whether there is. That is, it is determined whether or not a value (third temperature difference value) obtained by subtracting a new defrost entry temperature from the newly measured external heat exchange temperature is equal to or less than a predetermined positive value (γ). Here, the positive predetermined value (γ) is a value smaller than the positive predetermined value (β).

  If "YES" is determined in the step S10, the rotational speed of the outdoor fan 5 is decreased in the step S11 (third control). The rotational speed of the outdoor fan 5 set in step S11 is a value obtained by subtracting the predetermined rotational speed (X) from the initial rotational speed.

  After reducing the rotation speed of the outdoor fan 5 in step S11, in step S12, it waits for the newly measured outside heat exchange temperature to become lower than the new defrosting entry temperature. When the external heat exchange temperature becomes equal to or lower than the defrosting entry temperature in step S12, the defrosting operation is started in step S13.

  From the above, by controlling the rotational speed of the control unit 7, the rotational speed of the outdoor fan 5 can be lowered stepwise to increase the heating operation time while suppressing the blowing sound of the outdoor fan 5. Further, when the external heat exchange temperature becomes equal to or lower than the defrost entry temperature, the defrost operation can be started.

4 Outdoor heat exchanger 5 Outdoor fan 6 Temperature sensor 7 Control unit

Claims (3)

Outdoor heat exchanger (4),
An outdoor fan (5) for generating a flow of air passing through the outdoor heat exchanger (4);
A temperature sensor (6) for measuring an outdoor heat exchanger temperature of the outdoor heat exchanger (4);
A control unit (7) for controlling the rotational speed of the outdoor fan (5) by the outdoor heat exchanger temperature and the defrosting entry temperature (DIN) for starting the defrosting operation;
With
Before the defrosting operation during heating, the control unit (7) sets the rotation speed of the outdoor fan (5) to the initial rotation speed at the start of the heating operation, and then the outdoor heat exchanger temperature and the defrosting operation. Based on the rush temperature, the rotational speed control is performed in a stepwise manner until reaching the rotational speed obtained by subtracting the predetermined rotational speed (X) from the initial rotational speed,
In the rotational speed control, the control unit (7) is triggered by the fact that the outdoor heat exchanger temperature falls below a value obtained by adding a positive first predetermined value (α) to the defrost entry temperature. The rotational speed of the outdoor fan (5) is decreased , and the outdoor heat exchanger temperature is further equal to or less than a value obtained by adding a positive second predetermined value (β) smaller than the first predetermined value to the defrost entry temperature. triggered by a decrease in the Ru lowers the rotational speed of the outdoor fan (5), the outdoor unit of the air conditioner. In the rotational speed control, the control unit (7) is further configured such that the outdoor heat exchanger temperature is further a positive third predetermined value (γ) smaller than the second predetermined value (β) at the defrosting entry temperature. triggered by lowering the value below the addition, the outdoor fan (5) of Ru lowers the rotational speed, the outdoor unit of an air conditioner according to claim 1.   The outdoor unit for an air conditioner according to claim 1 or 2, wherein the defrosting operation is started after the outdoor heat exchanger temperature becomes equal to or lower than the defrosting entry temperature.

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