JP2006138579A - 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, and a compressor operational frequency determining means 8, 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 an upper limit value of the compressor operational frequency is implemented before frosting by the compressor operational frequency determining means 8, so that the compressor operational frequency 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 above-described conventional problems, the air conditioner of the present invention detects the outdoor heat exchanger temperature during heating operation, and sets the outdoor heat exchanger temperature within a predetermined range according to a preset data table. The upper limit value fa of the compressor operating frequency is changed so as to be adjusted.

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

  An air conditioner according to the present invention is the air conditioner according to claim 1, wherein the compressor operating frequency fa has a lower limit value.

  As a result, the heating operation state can be set according to the state of the outdoor heat exchanger, and a significant decrease in heating capacity can be avoided.

  Furthermore, the air conditioner of the present invention is configured such that the control for changing the compressor operating frequency fa can be interrupted by operating a predetermined switch.

  This makes it possible to perform the same compressor frequency control as before without relying 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 detects the outdoor heat exchanger temperature at the time of heating operation, and changes the upper limit fa of the compressor operating frequency so as to adjust the outdoor heat exchanger temperature within a predetermined range according to a preset data table This reduces frost formation on the outdoor heat exchanger during heating operation at low outdoor temperatures, avoids a decrease in heat exchange efficiency due to frost formation, and does not cause a significant decrease in heating capacity. The frequency of frost operation can also be reduced and the comfort of the indoor living environment can be improved.

  In the second aspect of the invention, in particular, by setting a lower limit value for the compressor operating frequency fa of the first aspect of the invention, the heating operation state can be set according to the state of the outdoor heat exchanger.

  In the third aspect of the invention, in particular, the compressor operating frequency control of the first or second aspect of the invention can be interrupted by operating a predetermined switch. Compressor frequency control is performed.

  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, a microcomputer 1, a compressor 2 having a variable operating frequency, and an outdoor heat exchanger temperature detector 3 that detects an outdoor heat exchanger temperature Tcond and sends the value to the microcomputer 1 are provided. Yes. The microcomputer 1 includes a data table 4 in which an upper limit value and a lower limit value of the outdoor heat exchanger outdoor temperature are set in advance, and a data comparison unit 6 for comparing and analogizing the data table 4 and the outdoor heat exchanger temperature data Tcond. And there exists the calculating part 7 which estimates the frost formation state of the outdoor heat exchanger after a driving | operation continuation based on the data obtained from the data comparison part 6. FIG. The compressor operating frequency determining means 8 performs an operation of changing the compressor operating frequency in accordance with the predicted idea state of the calculation unit 7.

Since the correlation between the frost formation state on the outdoor heat exchanger with respect to any outdoor heat exchanger temperature is contrasted in the data table 4, the measured temperature of the outdoor heat exchanger is applied to 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. The outdoor heat exchanger temperature detection unit 3 detects the outdoor heat exchanger temperature Tcond (ST11), and a data table 4 in which the correlation between the outdoor heat exchanger temperature and the frosting state on the outdoor heat exchanger is set in advance. And Tcond are compared and estimated by the data comparison unit 6 (ST12), and the frosting state after the operation is continued is predicted by the calculation unit 7 (ST13). The operation of changing the frequency is performed (ST14).

  As described above, in the present embodiment, the measured outdoor heat exchanger temperature Tcond is compared with the data table 4, and the outdoor heat exchanger temperature is determined from the upper limit value of the outdoor heat exchanger temperature set in the data table 4 in advance. By reducing the compressor operating frequency before the exchanger begins to form frost, frost formation on the outdoor heat exchanger can be suppressed. 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, if 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 compressor operating frequency upper limit value fa is multiplied by the current frequency upper limit value f and the constant k1. If the value reaches the lower limit value T2, the compressor operating frequency upper limit value is set to a value obtained by multiplying the current frequency upper limit value k1 × f by a constant k2. This calculation is repeated, and when the compressor operating frequency upper limit value fa reaches the lower limit value f0, this is set as the lower limit.

FIG. 4 is a flowchart of the air conditioner according to the second embodiment of the present invention. The outdoor heat exchanger temperature detection unit 3 detects the outdoor heat exchanger temperature Tcond (ST21), and a data table 4 in which the correlation between the outdoor heat exchanger temperature and the frost formation state on the outdoor heat exchanger is set in advance. And Tcond are compared by analogy in the data comparison unit 6 (ST22), Tcond is compared with the upper limit value T1 preset in the data table 4, and if Tcond is equal to or greater than T1 (ST23), the compressor operating frequency If the upper limit fa is a value obtained by multiplying the current compressor operating frequency f by a constant k1 (ST24), and Tcond is lower than T1 (ST23) and lower than the lower limit T2 (ST25), the compressor operating frequency upper limit fa Is a value obtained by multiplying the current compressor operating frequency k1 × f by a constant k2 (ST26), and if Tcond is lower than T1 (ST23) and higher than the lower limit value T2 (ST25), the compressor operating frequency The number upper limit fa are those which do not change. Further, if the lower limit value of the obtained compressor operating frequency upper limit value fa is equal to or less than the predetermined value f0 (ST27), the lower limit value of the compressor operating frequency upper limit value fa is fixed to f0 (ST28).

This makes it possible to accurately predict the frost formation state on the outdoor heat exchanger while preventing a large decrease in capacity due to excessive reduction in the compressor operating frequency, and to suppress frost formation on the outdoor heat exchanger. Can do.
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)
Furthermore, the air conditioner of the present invention is configured such that the control for changing the compressor operating frequency upper limit value can be interrupted by the operation of the remote controller 9 or the main body operation switch 10 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.

The block diagram of the air conditioner in Embodiment 1 of this invention Operation | movement conceptual diagram of the air conditioner in Embodiment 2 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 Outdoor heat exchanger temperature detection part 4 Data table 6 Data comparison part 7 Calculation part 8 Compressor operating frequency determination means 9 Remote controller 10 Main body operation switch

Claims (3)

Indoor and outdoor heat exchangers, a compressor with variable operating frequency, an outdoor heat exchanger temperature detecting unit for detecting the temperature Tcond of the outdoor heat exchanger, the compressor operating frequency determining means, and its output An air conditioner having means for detecting an outdoor heat exchanger temperature during heating operation and changing an upper limit value fa of a compressor operating frequency according to a preset data table Machine. The air conditioner according to claim 1, wherein the compressor operating frequency fa has a lower limit. The air conditioner according to claim 1 or 2, wherein when the predetermined switch of the air conditioner is pressed, the control to change the upper limit value fa of the compressor operating frequency is canceled.

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