JP2008128608A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent frost formation on an indoor unit without degrading cooling comfort in starting an operation. <P>SOLUTION: An outdoor control portion 13 sets a frequency of a compressor 1 to be higher for a specific time after starting a cooling operation, then sets a maximum frequency of the compressor high when a humidity is low, and sets the maximum frequency of the compressor low when the humidity is high. Here, an indoor control portion 12 transmits the temperature difference between an indoor temperature from an indoor temperature sensor 8 and a set temperature from a remote controller 18 to the outdoor control portion 13, and the outdoor control portion 13 decides a compressor operation rotational frequency on the basis of the temperature difference, and controls the rotational frequency of the compressor 1 through an invertor circuit 17. Further the indoor control portion 12 determines a humidity zone from a high humidity zone, an intermediate humidity zone and a low humidity zone on the basis of the indoor humidity from the indoor humidity sensor 9 and the lapse time, and transmits the same to the outdoor control portion 13, and the outdoor control portion 13 decides the compressor maximum rotational frequency on the basis of the humidity zone, and controls the rotational frequency of the compressor 1 through the invertor circuit 17. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air conditioner, and more particularly to an air conditioner that performs a cooling operation.

  In conventional air conditioners, dew prevention control is disclosed in which the maximum number of rotations of the compressor is set lower than the step-shaped limit curve that does not always cause condensation with respect to room humidity or room enthalpy. (For example, refer to Patent Document 1).

JP-A-64-33457 (Claim 2, page 310, lower right column, lines 8 to 14, page 311, lower left column, line 1 to page, lower right column, line 11, line 2)

  In the conventional dew control in an air conditioner, the maximum number of revolutions of the compressor may be set low depending on the humidity from the start of operation, and cooling comfort at the start of operation has not been considered.

  The present invention has been made to solve the above-described problems, and a first object thereof is to obtain an air conditioner that does not impair the cooling comfort at the start of operation.

  Moreover, the 2nd objective is to obtain the air conditioner which can prevent that dew adheres to the indoor unit of an air conditioner.

  During cooling operation, when the blow-out temperature is low, there is a risk that the indoor unit will be dewed and dripping if time passes. The dew adhering to the indoor unit grows with the passage of time, and the amount of the dew increases. However, it often takes a considerable amount of time to grow after the dew begins to attach. Therefore, priority is given to cooling comfort until a certain time after the start of cooling, and even if the frequency of the compressor is set higher, the influence of the exposure is small. However, if the dew is left for a long time, it will grow and drop. Therefore, it is necessary to regulate the maximum rotation speed of the compressor. FIG. 7 shows the relationship between room humidity and dew point temperature. For example, if the indoor temperature is 27 ° C., and the indoor relative humidity is 80%, the air will condense when it falls below 23.5 ° C. Further, when the indoor temperature is 27 ° C. and the indoor relative humidity is 40%, dew condensation occurs when the temperature drops below 12.7 ° C. In this way, condensation is less likely at lower humidity.

  Therefore, the compressor frequency is set higher for a predetermined time after the start of cooling, and the compressor frequency is set higher, and when the humidity is low, the maximum frequency of the compressor is set higher when the humidity is low. Sometimes, by setting the maximum frequency of the compressor lower, it is possible to prevent dew condensation without impairing the cooling comfort until a certain time after the start of cooling.

  An air conditioner according to the present invention includes at least a compressor, a four-way switching valve, an outdoor heat exchanger, a refrigerant decompression device, a refrigerant circuit in which indoor heat exchangers are sequentially connected by refrigerant piping, and an inverter. An outdoor unit having an outdoor control unit that controls the rotation speed of the compressor, and the outdoor control unit sets the maximum rotation speed of the compressor to a predetermined frequency or more to prevent dew condensation within a predetermined time after the start of the cooling operation. It is characterized by not performing control.

  According to the present invention, the compressor comfort is prioritized for a predetermined time after the start of cooling, and the compressor frequency is set higher than a predetermined value. After the predetermined time has elapsed, when the humidity is low after dehumidification by a known technique. By setting the maximum frequency of the compressor higher and setting the maximum frequency of the compressor lower when the humidity is high, it is possible to prevent dew condensation without impairing the cooling comfort until a certain time after the start of cooling. It becomes.

Embodiment 1 FIG.
FIG. 1 shows a configuration diagram of a heat pump type air conditioner according to Embodiment 1 of the present invention. The air conditioner 20 sequentially connects the compressor 1, the four-way switching valve 2, the outdoor heat exchanger 3, the refrigerant decompression device 4, and the indoor heat exchanger 5 with refrigerant piping, and the blower 6 of the outdoor heat exchanger and the indoor heat exchange. A refrigeration cycle is configured with a blower 7. Further, an indoor temperature sensor 8 for detecting the indoor temperature and an indoor humidity sensor 9 for detecting the relative humidity in the room are provided. Further, a filter 10 for preventing dust in the air from entering the indoor heat exchanger 5 and an automatic filter cleaning mechanism 11 capable of automatically cleaning the filter periodically are provided. The four-way switching valve 2 can be switched between a cooling operation and a heating operation, and forms a heating cycle by switching in the direction of the solid arrow, and forms a cooling cycle by switching in the direction of the broken arrow.

FIG. 2 is a block diagram showing a control system of the air conditioner shown in FIG.
As shown in FIG. 2, the air conditioner 20 includes an indoor control unit 12 configured by a microcomputer mounted on an indoor unit, and an outdoor control unit 13 configured by a microcomputer mounted on the outdoor unit. . The indoor control unit 12 and the outdoor control unit 13 are connected by a connection line 14 and exchange data and control signals with each other. The indoor blower 7 is controlled by the indoor control unit 12 via the rotation speed control circuit 15. The outdoor sending machine 8 is controlled by the outdoor control unit 13 via the rotation speed control circuit 16. The four-way switching valve 2 and the refrigerant pressure reducing device 4 are controlled by the outdoor control unit 13.
The room controller 12 calculates the room temperature from the signal input from the room temperature sensor 8, and the set temperature data sent from the remote controller 18 and the room temperature when the user performs a desired setting using the remote controller. The temperature difference is calculated and data is sent to the outdoor control unit 13. The outdoor control unit 13 determines the rotational speed of the compressor from the temperature difference data sent from the indoor 12, and controls the rotational speed of the compressor 1 through the inverter circuit 17.
The indoor control unit 12 calculates the indoor humidity from the signal input from the indoor humidity sensor 9. In addition, the indoor control unit 12 starts the built-in timer from the time when the operation is started by the remote controller 18 and causes the elapsed time to be counted. Therefore, the indoor control unit 12 determines one of the high humidity zone, the middle humidity zone, and the low humidity zone based on the value of the indoor humidity and the elapsed time counted by the timer, and uses the outdoor humidity as humidity zone information. Data is sent to the control unit 13.
The outdoor control unit 13 determines the maximum compressor rotational speed based on the humidity band sent from the indoor control unit 12. When the compressor operating rotational speed exceeds the maximum compressor rotational speed, the outdoor control unit 13 corrects the compressor operating rotational speed to a value that does not exceed the compressor maximum rotational speed, and the inverter circuit 17 The number of rotations of the compressor 1 is controlled via This makes it possible to always ensure an accurate maximum compressor speed.

FIG. 3 is a diagram showing a set value of the maximum rotation speed of the compressor. FIG. 4 shows a flowchart for setting the maximum rotational speed of the compressor by the control means 13. In this example, a case where the maximum number of rotations of the compressor is set to three values of a maximum value (comp_Hi) Hz, an intermediate value (comp_Me) Hz, and a minimum value (comp_Lo) Hz will be described.
The control means 13 sets the maximum rotation speed of the compressor to the maximum value (comp_Hi) Hz regardless of the relative humidity value until (tuyu1) time after the start of the cooling operation (steps S41 and S42). Thereby, since the compressor 1 is operated at the maximum capacity, it is possible to prevent dew condensation without impairing the cooling comfort until a certain time after the start of cooling. The above (tuyu1) time sets the time for the room temperature to reach the set temperature in an average house. In an average house, since it is possible to reach the set temperature in about 1 hour, it is preferable to set it to about 1 hour. However, it may be set shorter if there is a risk of dew dropping.
In addition, the control means 13 maximizes the maximum rotational speed of the compressor in the low humidity zone when the relative humidity is less than (Lositu)% during (tuyu1) time and less than (tuyu2) time after the start of the cooling operation. The value (comp_Hi) Hz is set (steps S43, S45, S46). If the relative humidity is (Lositu)% or more, the compressor maximum rotation speed in the medium humidity range is set to the intermediate value (comp_Me) Hz (steps). S43, S44, S46).
In addition, when the relative humidity is less than (Lositu)%, the control means 13 sets the maximum rotation speed of the compressor in the low humidity zone to the maximum value (comp_Hi) Hz after the time of starting the cooling operation (tuyu2) or more. (Steps S47, S50) If the relative humidity is (Lositu)% or more and less than (Hisitu)%, the maximum rotational speed of the compressor in the intermediate humidity zone is set to an intermediate value (comp_Me) Hz (Steps S47, S49). ) When the relative humidity is (Hisitu) or higher, the maximum rotational speed of the high humidity compressor is set to the minimum value (comp_Lo) Hz (steps S47 and S48).
As described above, even when the humidity is high, by regulating the maximum frequency of the compressor over time, it becomes possible to prevent deterioration of cooling comfort while preventing dew condensation.
3 and 4, the humidity zone is divided into three humidity zones and the time zone is divided into three. However, the present invention is not limited to this, and three or more may be used. In this case, the same effect is obtained.

The maximum value (comp_Hi) Hz is the maximum number of revolutions that can be used in the compressor used in the air conditioner (the maximum value in the range where normal continuous operation is possible without the protective device in the main unit control being activated). Although it depends on the type, it is desirable to set (about 100 Hz in a 4.0 kw air conditioner). By doing in this way, it is possible to exhibit the maximum capability of the air conditioner, and to contribute to the cooling comfort to the maximum extent.
The intermediate value (comp_Me) Hz is desirably set to a rotational speed that is equal to or higher than the cooling capacity of the applicable multiplier of the air conditioner. By doing in this way, the cooling rated capacity can be exhibited, and the necessary cooling comfort of the air conditioner can be ensured. (Depending on the type of compressor, about 70 Hz is set in a 4.0 kW air conditioner.)
The minimum value (comp_Lo) Hz is desirably set to a rotational speed that is 2/3 or more of the cooling capacity of the applied multiplier of the air conditioner. By doing in this way, it becomes possible to satisfy cooling comfort substantially in the environment where an air conditioner is normally used. (Depending on the type of compressor, about 50 Hz is set in a 4.0 kw air conditioner.)
Usually, the amount of dew on the indoor unit increases after about 4 hours, and is combined with surrounding dewed water and dropped from the indoor unit. Therefore, it is desirable to set the (tuyu2) time to about 3 hours with a margin of about 1 hour. However, it is better to set a shorter value in the case of dripping earlier by prior evaluation.
(Hisitu)% is set to a value that was found in the pre-evaluation that no dew condensation occurs even if it is operated for a long time at (comp_Lo) Hz, but the relative humidity is 60 in the environment used in a normal air conditioner. If it is less than or equal to%, almost no condensation occurs, so it is set to about 60%.
(Lositu)% is set to a value determined in the pre-evaluation that no dew condensation occurs even if it is operated for a long time at (comp_Hi) Hz.

FIG. 5 shows an example of changes in the maximum rotational speed of the compressor during the cooling operation. The compressor is operated at (comp_Hi) Hz until the time (tuyu1) after the start of operation. (Tuyu1) When the time has passed, determine which humidity range the room humidity is in. Since the room humidity is (Lositu)% or more and is in the middle humidity range, the maximum rotation speed of the compressor is set to (comp_Me) Hz. (Tuyu2) When the time has passed, determine which humidity range the room humidity is in. Since the indoor humidity is (Lositu)% or more and less than (Hisitu)%, the maximum rotation speed of the compressor is set to (comp_Me) Hz as it is. Thereafter, when the indoor humidity becomes less than (Lositu)%, the maximum rotational speed of the compressor is set to comp_Hi) Hz.
In FIG. 5, the humidity zone is divided into three humidity zones and the time zone is divided into three, but three or more may be used.

FIG. 6 is an explanatory view showing the operation of the automatic filter cleaning mechanism 11.
As shown in FIG. 6, the automatic filter cleaning mechanism 11 scrapes off dust adhering to the filter 10 with a brush while moving the filter 10 and collects it in a dust box. When the automatic filter cleaning mechanism 11 fails, dust gradually accumulates in the filter 10. When dust accumulates in the filter 10, the amount of air passing through the indoor heat exchanger 5 is reduced, so that the temperature of the indoor heat exchanger 5 is reduced during the cooling operation. When the temperature of the indoor heat exchanger 5 is lowered, the blowing temperature is lowered, and there is a possibility that dew is generated. Therefore, when the automatic filter cleaning mechanism 10 breaks down, the indoor control unit 12 reduces the rotational speed so that there is no risk of dew condensation even if the air volume that passes through the maximum frequency of the compressor decreases.
The indoor control unit 12 detects a failure of the automatic filter cleaning mechanism 11 as follows.
The filter 10 is configured to be rotationally movable within a predetermined range by driving a motor (hereinafter referred to as “movable”). The filter movable end is closed at the time of non-operation or when the operation is completed to generate an ON signal. A limit switch that opens and emits an OFF signal is installed. The indoor control unit 12 determines whether or not the filter 10 is operating based on time by a limit switch and a timer (not shown). That is, the indoor control unit 12 issues a movement command to the filter 10 to start the movement of the filter 10, and immediately monitors whether or not a change signal from ON to OFF is received from the limit switch. When the change signal from ON to OFF is not received even after a predetermined time (several seconds) has passed, it is determined that the cleaning did not operate normally, and the motor of the filter cleaning mechanism is stopped. An alarm indicating a failure is output in the form of a display or ringing. Furthermore, when the automatic filter cleaning mechanism 10 breaks down, the indoor control unit 12 reduces the rotational speed so that there is no risk of dew condensation even if the air volume that passes through the maximum frequency of the compressor decreases.
Further, after receiving a normal change signal from ON to OFF from the limit switch, it is monitored whether the cleaning is completed and the filter returns to the position of the limit switch. In this case, the normal time required until the filter 10 returns to the original position, the limit switch is closed, and the change signal from OFF to ON is generated is learned in advance. A time with a margin is set as a timeout time in a built-in storage unit. Thus, when the automatic filter cleaning mechanism 11 is actually operated, the indoor control unit 12 starts to move the filter 10, and the filter 10 returns to the original position within the time-out period and the limit switch is turned off. If a change signal to ON is received, it is determined that the cleaning has been completed normally. On the other hand, if the change signal from the above-mentioned OFF to ON is not received from the limit switch even after the time-out period has elapsed, it is determined that the cleaning did not operate normally due to a failure or the like, and the motor of the filter cleaning mechanism is stopped. An alarm indicating a failure is output in the form of a display or ringing. Furthermore, when the automatic filter cleaning mechanism 10 breaks down, the indoor control unit 12 reduces the rotational speed so that there is no risk of dew condensation even if the air volume that passes through the maximum frequency of the compressor decreases.
Thereby, dew can be prevented.

In the conventional air conditioner, if the fan speed set by the remote controller etc. is different, such as strong, medium, or weak, the maximum rotation speed of the compressor is changed according to this speed, but in this case, Depending on the fan speed, operation of the above compressor at (comp_Hi) Hz or (comp_Me) Hz may be suppressed, resulting in reduced cooling comfort or dew operation. There was a fear.
In order to solve such a problem, the indoor control unit 12 and the outdoor control unit 13 maintain the operation of the first embodiment as it is regardless of whether the fan speed is strong, medium, or weak.
Thereby, as described above, the cooling comfort can be maintained as it is, and the operation with dew can be prevented.

The block diagram of the heat pump type air conditioner in embodiment of this invention is shown. It is a block diagram showing the control system of the air conditioner shown in FIG. It is a figure which shows the setting value of the compressor maximum rotation speed in embodiment of this invention. It is a figure which shows the flowchart of compressor maximum rotation speed setting in embodiment of this invention. It is a figure which shows one example of the compressor maximum rotation speed change at the time of air_conditionaing | cooling operation in embodiment of this invention. It is explanatory drawing which shows operation | movement of the automatic filter cleaning mechanism. It is a figure which shows the relationship between indoor relative humidity and dew point temperature.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 way switching valve, 3 Outdoor heat exchanger, 4 Refrigerant decompression device, 5 Indoor heat exchanger, 6 Outdoor blower, 7 Indoor blower, 8 Indoor temperature sensor, 9 Indoor humidity sensor, 10 Filter, 11 Automatic filter Cleaning mechanism, 12 indoor control unit, 13 outdoor control unit, 14 connection line, 15 rotation speed control circuit, 16 rotation speed control circuit, 17 inverter circuit, 18 remote control, 20 air conditioner.

Claims (6)

At least a compressor having a variable speed, a four-way switching valve, an outdoor heat exchanger, a refrigerant pressure reducing device, a refrigerant circuit in which indoor heat exchangers are sequentially connected by a refrigerant pipe, and the speed of the compressor are controlled via an inverter. In an air conditioner including an outdoor unit having an outdoor control unit,
The outdoor control unit does not perform dew prevention control by setting the maximum rotational speed of the compressor to a certain frequency or more within a predetermined time after the start of the cooling operation. An indoor humidity sensor for detecting indoor humidity;
An indoor control unit that determines whether the humidity zone is a high humidity zone, a middle humidity zone, or a low humidity zone based on the indoor humidity and the elapsed time from the indoor humidity sensor, and outputs the humidity zone information; and
The air conditioner according to claim 1, wherein the outdoor control unit determines a maximum compressor rotation speed based on humidity band information from the indoor control unit after the predetermined time has elapsed.   The outdoor control unit determines the maximum compressor rotation speed to be equal to or less than a first value when the humidity band information from the indoor control unit is a high humidity band, and the maximum compressor rotation speed when the humidity control is in the middle humidity band. The air conditioner according to claim 2, wherein the air conditioner is determined to be not less than the first value and not more than the second value, and when the humidity is low, the maximum rotational speed of the compressor is determined to be not less than the second value.   The outdoor control unit 13 corrects the compressor operation rotational speed to a value that does not exceed the maximum compressor rotational speed when the compressor operational rotational speed exceeds the maximum compressor rotational speed. The air conditioner according to any one of claims 1 to 3.   The air conditioner according to any one of claims 1 to 4, wherein the outdoor control unit determines the maximum number of rotations of the compressor for each rotation speed of the indoor blower. A filter that is provided in the indoor unit and that filters indoor air dust, a limit switch that is provided at a stable position of the filter, and a filter drive mechanism that moves the filter within a predetermined range; An automatic filter cleaning mechanism that scrapes dust adhering to the filter by a brush fixed at a predetermined position when the filter is moved by the drive mechanism coming into contact with the filter;
The indoor control unit regulates the maximum rotation speed of the compressor when a signal from the limit switch does not change even after a predetermined time has elapsed after starting the filter drive mechanism of the automatic filter cleaning mechanism. The air conditioner according to any one of claims 1 to 5.

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