JP2006138580A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner capable of preventing rapid frosting on an outdoor heat exchanger during a heating operation when an outdoor air temperature is low, and keeping comfortable indoor dwelling environment. <P>SOLUTION: This air conditioner comprises indoor-side and outdoor-side heat exchangers, an operational frequency variable-compressor 2, an outdoor heat exchanger temperature detecting portion 3, an outdoor unit operational current detecting portion 11 and an electric current setting means, a frost formation state of the outdoor heat exchanger after continuation of operation is estimated from a temperature of the outdoor heat exchanger temperature in the heating operation on the basis of a predetermined data table 4 (not displayed), and the operation for changing a rotational frequency of an indoor air blower is implemented before frosting by an indoor air blower rotational frequency setting means, so that the rotational frequency of the indoor air blower can be lowered before the start of frost formation on the outdoor heat exchanger, and the frosting on the outdoor heat exchanger can be inhibited. As a result, the heat exchanging efficiency of the outdoor heat exchanger can be secured, and the amenity of indoor dwelling environment can be secured. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air conditioner having a variable compressor operating frequency, and more particularly to a heating operation.

  Conventionally, in the heating operation of a compressor operating frequency variable type air conditioner, particularly when the outdoor air temperature is low, the operating frequency of the compressor is maximized to ensure a high heating capacity. In this case, since the operating frequency of the compressor is high, the compressor suction pressure decreases, and the refrigerant evaporation temperature in the outdoor heat exchanger decreases. Furthermore, since the outdoor air temperature is low, the temperature of the outdoor heat exchanger decreases synergistically, and when it becomes below freezing, frost adheres to the outdoor heat exchanger and grows. At this time, the efficiency of the action of taking heat from the outdoor air is reduced, and the heating capacity is greatly reduced. Therefore, when a certain condition is satisfied, a method of defrosting the outdoor heat exchanger by temporarily interrupting the heating operation and switching the refrigeration cycle in reverse is widely used (see, for example, Patent Documents 1 and 2). .

FIG. 5 is a flowchart of a conventional air conditioner and shows an example of conventional defrosting operation control. First, the compressor integration timer is started (ST1), and when the integration time is not less than a predetermined value (here, 40 minutes) (ST2) and the heat exchange temperature is not more than a predetermined value (here, −6 ° C.) (ST3), If the heat exchange temperature is equal to or lower than a predetermined value (here, −10 ° C.) (ST4) or the outside air temperature is equal to or lower than a predetermined value (here, −3 ° C.), the process proceeds to a long defrosting operation (ST5). If the heat exchange temperature is higher than a predetermined value (here, −10 ° C.) (ST4) and the outside air temperature is higher than a predetermined value (here, −3 ° C.), the process proceeds to a process (ST7) for a short defrosting operation.
JP-A-8-338673 JP-A-5-106945

  However, in the conventional technique, during the defrosting operation, the heating operation is temporarily interrupted, and the refrigeration cycle is switched in reverse, that is, the cooling operation is performed. Despite being instructed, the heating operation stops and the cold wind blows out, which may cause a misunderstanding that it is a malfunction or impair comfort. In addition, in order not to apply cold air directly to the user, it is possible to perform cooling operation by closing the outlet, etc., but in that case, from the user's side, although instructing heating operation, Since the heating operation stops, the air outlet closes and the wind does not come out, there is a possibility that it may be misunderstood as a failure.

  Furthermore, even before the start of the defrosting operation, once the outdoor heat exchanger is frosted and the growth of frost begins, the frost inhibits the ventilation of the outdoor unit, and the heat exchange efficiency of the outdoor heat exchanger decreases at an accelerated rate. There was a problem that the heating capacity was greatly reduced.

  In view of these problems, the present invention suppresses frost formation on the outdoor heat exchanger during heating operation, avoids a significant decrease in heating capacity, and further reduces the frequency of defrosting operation.

  In order to solve the conventional problems, the air conditioner of the present invention fixes the outdoor unit operating current upper limit value, detects the outdoor heat exchanger temperature during heating operation, and according to a preset data table, The rotational speed of the indoor blower is changed so as to adjust the outdoor heat exchanger temperature within a predetermined range.

As a result, frost formation on the outdoor heat exchanger can be reduced in the heating operation at a low outdoor temperature, and a decrease in heat exchange efficiency due to frost formation can be avoided.

  Moreover, the air conditioner of this invention WHEREIN: The air conditioner of Claim 1 has a lower limit in the rotation speed of an indoor air blower.

  As a result, the heating operation continuation time can be extended and a significant reduction in heating capacity can be avoided.

  Moreover, the air conditioner of this invention has an upper limit in the rotation speed of an indoor air blower in the air conditioner of Claim 1.

  As a result, it is possible to extend the heating operation continuation time while avoiding a feeling of cold wind due to the strong wind hitting the human body and avoid a significant decrease in heating capacity.

  An air conditioner according to the present invention is the air conditioner according to claim 1, wherein the air conditioner detects the room air temperature and has two current control values determined by the room air temperature in accordance with a preset data table. This is what is provided.

This makes it possible to avoid a decrease in heating capacity in accordance with the load condition in the room and improve comfort.
Furthermore, the air conditioner of the present invention is configured such that the rotation speed control of the indoor unit can be interrupted by operating a predetermined switch.

  As a result, it is possible to perform the same rotational speed control of the indoor fan as in the conventional case without depending on the above control as necessary.

  The air conditioner of the present invention suppresses frost formation on the outdoor heat exchanger during the heating operation, thereby reducing the frequency of the defrosting operation without causing a significant decrease in the heating capacity. It will improve the comfort of the living environment.

  1st invention sets the operating current value of an outdoor unit so that it may become constant, detects the outdoor heat exchanger temperature at the time of heating operation, and according to the preset data table, the outdoor heat exchanger temperature of the predetermined range By changing the rotation speed of the indoor blower to adjust to, frost formation on the outdoor heat exchanger is reduced during heating operation at low outside air temperature, avoiding a decrease in heat exchange efficiency due to frost formation, and heating capacity In addition, the frequency of the defrosting operation can be reduced and the comfort of the indoor living environment can be improved.

  In the second aspect of the invention, in particular, by providing a lower limit value for the rotational speed of the indoor fan of the first aspect of the invention, it is possible to avoid a significant decrease in heating capacity while extending the heating operation continuation time.

  The third aspect of the invention extends the heating operation continuation time while reducing the feeling of cold wind due to the strong wind hitting the human body, particularly by providing an upper limit for the rotational speed of the indoor blower of the first or second aspect of the invention. A significant decrease in heating capacity can be avoided.

  In particular, the fourth invention detects the indoor air temperature of any one of the first to third inventions, and provides two or more current control values determined by the indoor air temperature according to a preset data table. As a result, it is possible to avoid a decrease in the heating capacity in accordance with the load condition in the room and to improve comfort.

  The fifth aspect of the invention is not limited to the above control as necessary, particularly by enabling the indoor fan rotation speed control of any one of the first to fourth aspects of the invention to be interrupted by a predetermined switch operation. The number of revolutions of the indoor fan is controlled similarly to the conventional one.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a block diagram of an air conditioner according to a first embodiment of the present invention.

  In FIG. 1, the microcomputer 1, the compressor 2 with variable operating frequency, the means 3 for detecting the outdoor unit current value and determining the current upper limit value, the outdoor heat exchanger temperature Tcond are detected, and the value is calculated by the microcomputer. The outdoor heat exchanger temperature detection part 4 sent out to the computer 1 is provided. The microcomputer 1 includes a data table 5 in which an upper limit value and a lower limit value of the outdoor heat exchanger temperature are set in advance, and a data comparison unit 7 for comparing and analogizing the data table 5 and the outdoor heat exchanger temperature data Tcond. There is a calculation unit 8 that predicts the frosting state of the outdoor heat exchanger after the operation is continued based on the data obtained from the data comparison unit 7. In accordance with the predicted frosting state of the calculation unit 8, the indoor fan rotation speed determination means 9 performs an operation of changing the rotation speed of the indoor fan.

  Since the correlation between the frost formation state on the outdoor heat exchanger and the arbitrary outdoor heat exchanger temperature is contrasted in the data table 5, the measured temperature of the outdoor heat exchanger is adjusted to the temperature of the outdoor heat exchanger. The frost state can be inferred.

FIG. 3 is a flowchart of the air conditioner according to the first embodiment of the present invention. After detecting the outdoor unit operating current value (ST11) and fixing the current value upper limit value (ST12), the outdoor heat exchanger temperature detector 4 detects the outdoor heat exchanger temperature Tcond (ST13), and the outdoor heat exchanger The data table 5 and Tcond in which the correlation between the temperature and the frosting state on the outdoor heat exchanger is set in advance are compared by the data comparison unit 7 (ST14), and the frosting after the operation is continued by the calculation unit 8 If the state is predicted (ST15) and frost formation is expected when the state is continued, an operation of changing the rotational speed of the indoor blower 14 is performed (ST16).

  As described above, in the present embodiment, the measured outdoor heat exchanger temperature Tcond is compared with the data table 5, and the outdoor heat exchanger temperature is determined from the upper limit value of the outdoor heat exchanger temperature set in the data table 5 in advance. By reducing the rotational speed of the indoor blower 14 before starting to frost on the exchanger, the condenser temperature tends to rise, but since the current upper limit value of the outdoor unit is constant, the operating frequency of the compressor is It falls, evaporator temperature rises and it can suppress frost formation to an outdoor heat exchanger.

  As a result, the heat exchange efficiency of the outdoor heat exchanger is ensured, and the comfort of the indoor living environment is ensured.

(Embodiment 2)
FIG. 2 is an operation conceptual diagram of the air conditioner according to the second embodiment of the present invention.

  In FIG. 2, when the outdoor heat exchanger temperature Tcond reaches the upper limit temperature T1 of the outdoor heat exchanger set in advance in the data table 4, the indoor fan rotational speed N is decreased by a predetermined rotational speed ΔN every predetermined time Δt. . At this time, since the outdoor operation current I is constant, the compressor frequency f decreases following substantially the indoor fan rotation speed N. When the indoor fan rotation speed N reaches the lower limit value N2, this is set as the lower limit.

As a result, it is possible to accurately predict the frosting state on the outdoor heat exchanger while preventing a large decrease in capacity due to the excessive decrease in the rotational speed N of the indoor fan, and suppress frosting on the outdoor heat exchanger. As a result, the heat exchange efficiency of the outdoor heat exchanger is ensured, and the comfort of the indoor living environment is ensured.

  Further, in FIG. 2, when the lower limit temperature T2 of the outdoor heat exchanger set in advance in the data table 4 is reached, the indoor fan rotational speed N is increased at a predetermined rotational speed ΔN every certain time Δt. At this time, since the outdoor operation current I is constant, the compressor frequency f increases substantially following the indoor fan rotation speed N. When the indoor fan rotation speed N reaches the upper limit value N1, this is set as the upper limit.

  This makes it possible to accurately predict the frost formation state on the outdoor heat exchanger while preventing the feeling of cold air due to excessive increase in the number of revolutions of the indoor fan, and can suppress frost formation on the outdoor heat exchanger. As a result, the heat exchange efficiency of the outdoor heat exchanger is ensured, and the comfort of the indoor living environment is ensured.

FIG. 4 is a flowchart of the air conditioner according to the second embodiment of the present invention. After detecting the outdoor unit operating current value (ST21) and fixing the current value upper limit value (ST22), the outdoor heat exchanger temperature detection unit 4 detects the outdoor heat exchanger temperature Tcond (ST23), and the outdoor heat exchanger The data table 5 and Tcond in which the correlation between the temperature and the frosting state on the outdoor heat exchanger is set in advance are compared by the data comparison unit 7 (ST24), and Tcond and the data table 5 are set in advance. The T13 is compared with a certain upper limit value T1 (ST25), and if Tcond is equal to or greater than T1, the timer 13 is reset (ST26) and starts counting. After a certain time Δt has elapsed (ST27), the indoor fan rotation speed N is set to a predetermined value. The rotational speed ΔN is lowered (ST28). If the indoor fan rotation speed N obtained here is equal to or less than a predetermined value N1 (ST29), the lower limit value is fixed to N1 (ST30).

  If Tcond is lower than T1 (ST25) and less than or equal to lower limit value T2 (ST31), the upper limit value of the current upper limit value is set to a value obtained by multiplying current current value I by constant k2 (ST26), and Tcond is lower than T1 ( If ST23) is higher than the lower limit value T2 (ST25), the timer 13 is reset (ST32) to start counting, and after a predetermined time Δt has elapsed (ST33), the indoor fan rotational speed N is increased by a predetermined rotational speed ΔN (ST34). ). If the indoor fan rotation speed N obtained here is equal to or greater than a predetermined value N2 (ST35), the upper limit value is fixed to N2 (ST36).

  If Tcond is lower than T1 (ST25) and greater than or equal to the lower limit value T2 (ST31), and if the lower limit value of the obtained current upper limit value is less than or equal to the predetermined value I3 (ST27), the lower limit value of the current upper limit value is set. It is fixed to I3 (ST28).

  As described above, it becomes possible to accurately predict the frost formation state on the outdoor heat exchanger while preventing a large decrease in capacity due to excessively low indoor fan rotation speed N or a feeling of cold air due to excessive increase, and outdoor heat exchange. As a result, the heat exchange efficiency of the outdoor heat exchanger is ensured, and the comfort of the indoor living environment is ensured.

(Embodiment 3)
By changing the outdoor current upper limit value according to the temperature detected by the indoor air temperature detection unit 10 in FIG. 1, it is possible to avoid a decrease in the heating capacity according to the indoor load condition and improve comfort.

(Embodiment 4)
Furthermore, the air conditioner of the present invention is configured such that the indoor blower rotation speed control can be interrupted by operating a remote controller 11 or a main body operation switch 12 provided in the main body.

  This makes it possible to perform the same compressor frequency control as before without relying on the above control as necessary.

  As described above, the air conditioner according to the present invention avoids a state in which ventilation is hindered by frost, the heat exchange efficiency of the outdoor heat exchanger is accelerated, and the heating capacity is greatly reduced. By suppressing frost formation on the outdoor heat exchanger during heating operation, the heating capacity is not significantly reduced, and the frequency of defrosting operation is also reduced, thereby improving the comfort of the indoor living environment. Is. .

Block diagram of an air conditioner according to Embodiments 1 and 4 of the present invention Operation | movement conceptual diagram of the air conditioner in Embodiment 2, 3 of this invention The flowchart of the air conditioner in the 1st Embodiment of this invention The flowchart of the air conditioner in the 2nd Embodiment of this invention Conventional air conditioner flowchart

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microcomputer 2 Compressor 3 Upper limit value determination means of outdoor current value 4 Outdoor heat exchanger temperature detection part 5 Data table 7 Data comparison part 8 Calculation part 9 Indoor fan rotation speed determination means 10 Indoor air temperature detection part 11 Remote controller 12 Main body operation switch 13 Timer 14 Indoor blower 15 Indoor blower rotation speed detection means

Claims (5)

Indoor and outdoor heat exchangers, compressors with variable operating frequency, outdoor unit operating current value detector and determining means, and outdoor heat exchanger temperature detector for detecting the temperature Tcond of the outdoor heat exchanger And an air conditioner having a rotation speed detection unit and a rotation speed setting means for the indoor fan, detecting the outdoor heat exchanger temperature during heating operation, and rotating the indoor fan according to a preset data table An air conditioner characterized by changing the number. The air conditioner according to claim 1, wherein the air blower has a lower limit value for the rotational speed of the indoor fan. 2. The air conditioner according to claim 1, wherein the air conditioner has an upper limit value for the number of rotations of the indoor blower. The air conditioner according to any one of claims 1 to 3, wherein the air conditioner has two or more current control values determined by the room air temperature in accordance with a room air temperature detection unit for detecting the room air temperature and a preset data table. Machine. The air conditioner in any one of Claims 1-4 which performs control which cancels | releases rotation speed control of an indoor air blower when the predetermined switch of an air conditioner is pressed down.

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