JP2001235211A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption of an air conditioner, when a condensation prevention function and a heating turn-on timer are used in combination. SOLUTION: The air conditioner is provided with a condensation prevention function to operate in a condensation prevention mode in order to prevent occurrence of condensation on walls and windows after a heating operation is stopped, and the prevention operation is automatically stopped. In the air conditioner, when a heating turn-on timer are set, a waiting time until the next heating operation is started by the heating turn-on timer after the suspension of the present heating operation is compared with a predetermined value for judgement. If the waiting time is equal to or larger than the value, an operation is performed in the condensation prevention mode, and if the waiting time is smaller than the value, the heating operation is continued, instead of the operation in the condensation prevention mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to an air conditioner having a dew condensation preventing function for preventing dew formation on a wall or a window after a heating operation is stopped.

[0002]

2. Description of the Related Art Separate type air conditioners composed of an indoor unit and an outdoor unit are widely used because they can produce cool air and warm air with relatively simple construction and can operate independently for each unit. I have. This separate type air conditioner includes a refrigerant circuit including a compressor, a four-way switching valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, and an accumulator. The indoor heat exchanger is arranged in the indoor unit, and performs cooling or heating by exchanging heat between the refrigerant and the indoor air. The outdoor heat exchanger is arranged in the outdoor unit, and evaporates or condenses the refrigerant by exchanging heat between the refrigerant and outdoor air. The compressor, the four-way switching valve, and the expansion valve compress / condense the refrigerant and perform cooling / heating.

[0003] In order to keep the indoor temperature comfortable in the winter, after the heating operation is performed by such an air conditioner, the indoor temperature gradually decreases. Especially in the middle of winter, since the outside air temperature is very low, the room temperature drops rapidly after the heating operation is stopped. When the indoor temperature decreases rapidly, the amount of saturated water vapor in the indoor air decreases, and particularly when the indoor humidity is high, there is a possibility that dew may be formed on walls and windows. Conventionally, after operating in a dew condensation prevention mode for a certain period of time after a heating operation, the operation is automatically stopped to prevent dew condensation on walls and windows. In many cases, a cooling mode in which dehumidification can be quickly performed is used as the dew condensation prevention mode.

Hereinafter, the term "prevention of dew condensation" refers to prevention of dew condensation on walls and windows after the heating operation is stopped.

[0005]

The function of preventing dew condensation is used, for example, after a heating operation is performed to keep the living room comfortable at night, for a certain period of time after the operation is stopped so that dew does not form on walls and windows. Often done. In general, the air conditioner is provided with a heating-on timer for starting a heating operation after a certain period of time so that a living room or the like is comfortable when the user wakes up the next morning. Consider a case in which both the heating-on timer and the dew condensation prevention function are set. If the dew condensation prevention function is set after performing the heating operation at night, the operation in the dew condensation prevention mode is performed for a fixed time after the heating operation is stopped, and thereafter, the operation is stopped. Then, the heating operation is started by the heating-on timer in the next morning, and the indoor temperature is brought close to the preset temperature.

However, if the time from the stoppage of the heating operation at night to the start of the heating operation in the next morning is very short, if the dew condensation prevention mode is performed in the cooling operation, the indoor temperature is reduced by the cooling operation and then the heating is performed again. The operation will increase the room temperature. In this case, a large power consumption is required to return the room temperature once lowered to an appropriate temperature again. In order to suppress a decrease in the indoor temperature, the operation in the reheat dry mode in which a part of the indoor heat exchanger functions as a condenser may be considered as a dew condensation prevention mode. The power consumption of the operation in the mode becomes very large.

An object of the present invention is to reduce the power consumption of an air conditioner when a condensation prevention function and a heating-on timer are used together.

[0008]

An air conditioner according to a first aspect of the present invention includes an indoor unit and an outdoor unit, and heats or cools indoor air by an indoor heat exchanger disposed in the indoor unit.
2. Description of the Related Art An air conditioner that performs a cooling operation or a heating operation by supplying heated or cooled air into a room by an indoor fan and has a dew condensation preventing function. The dew condensation prevention function is a function of automatically stopping after performing the operation in the dew condensation prevention mode in order to prevent dew formation on a wall or a window after the heating operation is stopped. When both the dew condensation prevention function and the heating-on timer are set, a selection is made between operation in the dew condensation prevention mode and operation in the heating mode based on a fixed reference. Here, the dew condensation prevention mode can be selected from any of a cooling mode in which dehumidification can be performed, a dry mode, and a reheating dry mode, and is usually performed by operating in a cooling mode in which dehumidification can be performed quickly.

In such an air conditioner, after the current heating operation is stopped, the waiting time until the next heating operation is started by the heating-on timer is compared with a predetermined determination value. If the waiting time is longer than the determination value, the operation is automatically stopped after a certain period of operation in the dew condensation prevention mode. If the waiting time is smaller than the determination value, the power consumption can be reduced by preventing the dew condensation by continuing the heating operation rather than by reducing the indoor temperature by the dew condensation prevention mode.
Continue heating operation to prevent condensation. The determination value is set by previously calculating a time in which the magnitude relationship between the power consumption when heating is continued during the waiting time and the power consumption when operating in the dew condensation prevention mode is reversed. . That is,
If the waiting time is longer than the determination value, the case where the heating operation is continued for a long time is disadvantageous in terms of power consumption,
Select the operation in the dew condensation prevention mode. Conversely, if the waiting time is shorter than the judgment value, the heating operation is continued rather than lowering the room temperature in operation in the dew condensation prevention mode and returning to the appropriate temperature again or operating in the reheat dry mode with large power consumption. This is advantageous in terms of power consumption.

According to such an air conditioner, both the dew condensation prevention function and the heating-on timer are set, and if the waiting time from the current stoppage of heating to the start of the next heating operation is short, By continuing the heating operation, it is possible to prevent dew condensation and reduce power consumption. An air conditioner according to a second aspect of the present invention is the air conditioner of the first aspect, wherein the determination value is changed according to the outdoor temperature. The magnitude of the power consumption when the dew condensation prevention operation is performed after the current heating operation and the power consumption when the heating operation is continued also change depending on the outdoor temperature. When the outdoor temperature is low, a large heating capacity is required to continue the heating operation and prevent condensation,
Continuing heating for a long time is disadvantageous in terms of power consumption. Therefore, the lower the outdoor temperature is, the smaller the determination value needs to be. Conversely, when the outdoor temperature is high, the determination value may be increased. As described above, by setting an appropriate determination value according to the outdoor temperature, it is possible to reliably select an operation mode in which power consumption is reduced.

In the air conditioner according to a third aspect, in the air conditioner according to the first or second aspect, the time during which the dew condensation operation is performed can be set by a user. In such an air conditioner, the user can select and set the time for operating in the dew condensation prevention mode after the heating operation. Since the likelihood of dew condensation varies depending on the size of the room in which the air conditioner is used, the arrangement of windows, and the like, it is desirable that the user can set the time for operating in the dew condensation prevention mode. If the operation time can be set in this way, the user can find and set the time necessary for appropriate dew condensation prevention from daily experience.

The air conditioner according to a fourth aspect of the present invention is the air conditioner according to any one of the first to third aspects, wherein the set temperature when operating in the heating mode instead of the dew condensation prevention mode is calculated from the room temperature and the room humidity. Is set to a temperature that is equal to or higher than the dew point temperature and is as low as possible. In such an air conditioner, the room temperature and the room humidity are detected, the dew point temperature is calculated from the detected values, and the set temperature is set to a temperature as low as possible or higher than the dew point temperature. Since the set temperature is equal to or higher than the dew point temperature, dew condensation can be prevented, and since the temperature is set as low as possible, power consumption can be minimized.

An air conditioner according to a fifth aspect of the present invention includes the first to fourth aspects.
In any of the air conditioners, the dew condensation prevention mode is a cooling mode. In such an air conditioner, when the operation is performed in the dew condensation prevention mode, the operation is performed in the cooling mode. In such an air conditioner, indoor air can be dehumidified in a short time in the cooling mode, thereby preventing dew condensation.

[0014] The air conditioner according to the sixth aspect of the present invention includes the first to fourth aspects.
In any of the above air conditioners, the dew condensation prevention mode is a dry mode. In the dry operation, the indoor heat exchanger functions as an evaporator for the refrigerant to cool and dehumidify the air and reduce the air flow of the indoor fan from that in the cooling operation. In such an air conditioner, since the air volume of the indoor fan is small, it is difficult for the cool air to reach the entire room, and it is possible to suppress a decrease in room temperature as compared with the case of the cooling mode.

[0015] The air conditioner according to the invention 7 comprises inventions 1 to 4
In any one of the air conditioners, the dew condensation prevention mode is a reheat dry mode. In the reheating dry mode, a part of the indoor heat exchanger functions as a condenser and the other functions as an evaporator. The condenser heats the room air, and the evaporator cools and dehumidifies the room air. Since the indoor air is heated in a part of the indoor heat exchanger, a decrease in room temperature can be further suppressed.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Overall Configuration] FIG. 1 is a block diagram showing a schematic configuration of an air conditioner to which an embodiment of the present invention is applied.
Shown in This air conditioner includes a refrigerant circuit 1 configured by connecting a compressor, a four-way switching valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, an accumulator, and the like in a ring shape, and a drive circuit for driving the refrigerant circuit 1. A drive circuit 2; frequency control means 3 for controlling the operating frequency of the compressor of the refrigerant circuit 1 via the drive circuit 2; and operation of the frequency control means 3 in a dew condensation preventing mode such as a cooling mode or a dry mode. And dew prevention means 4 for instructing the operation.

FIG. 2 shows the configuration of the refrigerant circuit 2. The refrigerant circuit 2 is connected to the compressor 11, a four-way switching valve 12 connected to the discharge side of the compressor 11, an outdoor heat exchanger 13 connected to the four-way switching valve 12, and an outdoor heat exchanger 13. Expansion valve 14, which is an electric expansion valve, an indoor heat exchanger 15 connected to expansion valve 14, and an accumulator connected to the suction side of compressor 11 for preventing liquid refrigerant from entering compressor 11. 16 are provided. Compressor 11, four-way switching valve 1
2, accumulator 16, outdoor heat exchanger 13, expansion valve 1
4 are provided in the outdoor unit, and the indoor heat exchanger 15 is provided in the indoor unit.

FIG. 3 shows a drive circuit 2 for driving the refrigerant circuit 1. The drive circuit 2 mainly includes an A / D converter 22 and an inverter 23. A / D converter 22
Converts a voltage supplied from a commercial AC power supply 21 into a DC voltage. The inverter 23 converts a DC voltage into an AC voltage according to a signal from the frequency control means 3. The output voltage from the inverter 23 causes the compressor 11
Is driven to form a refrigerant flow.

The frequency control means 3 and the dew condensation preventing means 4
Control unit 31 including a microprocessor as shown in FIG.
It is composed of The refrigerant circuit 1 and the drive circuit 2 are connected to the control unit 31. Further, a fan motor 32 for driving fans provided in the indoor unit and the outdoor unit is connected to the control unit 31. Further, a receiving unit 33 for receiving an instruction transmitted from the remote controller is connected to the control unit 31. The control unit 31 includes the receiving unit 3
A target temperature setting unit 34 for setting a target temperature based on the instruction received in 3 is connected. This target temperature setting unit 3
4 can be set as a predetermined area of the memory connected to the control unit 31. The control unit 31 includes an indoor temperature detecting unit 35 that is a temperature sensor that detects an indoor temperature, an outdoor temperature detecting unit 36 that is a temperature sensor that detects an outdoor temperature, and a humidity sensor that detects indoor humidity. Indoor humidity detector 37
And are connected.

In such an air conditioner, during the cooling operation, the four-way switching valve 12 is set to the position indicated by the solid line in FIG. 2, the expansion valve 14 is throttled to a predetermined opening, and the compressor 11 is started. The high-pressure refrigerant discharged from the compressor 11 is condensed in the outdoor heat exchanger 13 and then decompressed by the expansion valve 14. The decompressed low-pressure refrigerant evaporates in the indoor heat exchanger 15 and then passes through the four-way switching valve 12 and the accumulator 16 to the compressor 11.
Return to When the refrigerant evaporates in the indoor heat exchanger 15, the indoor air deprives the refrigerant of heat, and the deprived indoor air acts as cool air.

During the heating operation, the four-way switching valve 12 is set to the position indicated by the dotted line, and the expansion valve 14 is throttled to a predetermined opening.
Start The high-pressure refrigerant discharged from the compressor 11 is condensed in the indoor heat exchanger 15 and then decompressed by the expansion valve 14. The decompressed low-pressure refrigerant evaporates in the outdoor heat exchanger 13 and returns to the discharge side of the compressor 11 via the four-way switching valve 12 and the accumulator 13. When the refrigerant is condensed in the indoor heat exchanger 15, heat is released to the room air, and the room air that has absorbed this heat acts as warm air.

[Operation Control] Next, the control by the dew condensation preventing means after the heating operation in this embodiment will be described with reference to the flowcharts shown in FIGS. Step S1
Then, it is determined whether or not to start driving. In particular,
When a signal of a driving instruction from the remote controller is received or when the time set by the driving-on timer has elapsed, it is determined that driving is to be started, and the process proceeds to step S12. When the instruction signal from the remote controller is received by the receiving unit 33, the target temperature included in the instruction signal or a preset standard target temperature is stored in the target temperature setting unit 34, and the process proceeds to step S2. If it is determined that the time set by the operation-on timer has elapsed, the process proceeds to step S2 in order to operate at the target temperature stored in the target temperature setting unit 34 in the set operation mode.

In step S2, it is determined whether or not the instruction signal indicates a dry operation. When it is determined that the instruction signal indicates the dry operation, the process proceeds to step S3. In step S3, a normal dry operation is performed, and the humidity is controlled by the frequency control means 3 in FIG. If it is determined in step S2 that the instruction signal does not instruct the dry operation, the process proceeds to step S4. In step S4, it is determined whether or not the instruction signal is for instructing the cooling operation. If it is determined that the instruction signal indicates the cooling operation, the process proceeds to step S5. In step S5, normal cooling operation is performed, and the room temperature is controlled by the frequency control means 3 in FIG.

If it is determined in step S4 that the instruction signal does not indicate the cooling operation, the process proceeds to step S6. In step S6, it is determined whether or not the instruction signal indicates a heating operation. If it is determined that the instruction signal indicates a heating operation, the process proceeds to step S7. In step S7, a normal heating operation is performed, and the room temperature is controlled by the frequency control means 3 in FIG.

In step S8, it is determined whether or not to end the operation. Specifically, when the operation stop signal is received from the remote controller or when the time set by the operation off timer elapses, it is determined that the operation is to be stopped, and the process proceeds to step S9. If it is determined in step S8 that there is no operation stop signal from the remote controller and that the time set by the operation stop timer has not elapsed, the process proceeds to step S10.

In step S9, it is determined whether or not the heating operation in step S7 has been stopped and the condensation prevention function has been set. After the stop of the heating operation in step S7, if the dew condensation prevention operation is set, the process of FIG. 6 described later is performed. If the heating operation has not been stopped in step S7 or if the dew condensation prevention function has not been set, the process proceeds to step S10.

In step S10, another process is executed.
Move to step S1. [Condensation prevention operation] Next, FIG. 6 shows a process when the condensation prevention operation is set in step S9. Step S1
At 1, it is determined whether or not the heating-on timer is set. If the heating-on timer has not been set, the process proceeds to step S14. In step S14, the cooling operation as the dew condensation prevention mode is performed for a set time, and the process proceeds to step S15. In step S15, the operation in the dew condensation prevention mode is stopped, and the process proceeds to step S1.

If the heating-on timer has been set in step S11, the process proceeds to step S12. In step S12, the waiting time ts until the next heating operation is started by the heating-on timer after the current heating operation is represented by:
A comparison is made with a determination value td, which is a reference for selecting an operation mode with low power consumption. As the determination value td, the waiting time ts
The time during which the magnitude relationship between the power consumption when the heating is continued during the period and the power consumption when the operation is performed in the dew condensation prevention mode is reversed is calculated and set in advance. That is, the waiting time ts
Is larger than the determination value td, the operation in the dew condensation prevention mode is selected because the case where the heating operation is continued for a long time is disadvantageous in terms of power consumption. Conversely, when the waiting time ts is shorter than the determination value td, it is more advantageous in terms of power consumption to continue the heating operation than to lower the room temperature and return to an appropriate temperature in the operation in the dew condensation prevention mode.

Therefore, in step S12, ts
Is larger than td, the process proceeds to step S14, and the cooling operation as the dew condensation prevention mode is performed for the set time, similarly to the case where the heating-on timer is not set, and the process proceeds to step S15. In step S15,
The operation in the dew condensation prevention mode is stopped, and the process proceeds to step S1.

If ts is equal to or smaller than td in step S12, the process proceeds to step S13. In step S13, the operation in the heating mode is continued instead of the operation in the dew condensation prevention mode. The set temperature in the operation in the heating mode is set to be equal to or higher than the room temperature detected by the room temperature detection unit 35 and the room humidity detection unit 37 in FIG. 4 and the dew point temperature calculated from the room humidity. When the time set by the heating-on timer elapses, the process proceeds to step 1.

In step S1, the operation waits until a signal of an operation instruction from the remote controller is received or the time set by the operation-on timer elapses. If the heating-on timer has been set, the next heating operation is started after the set time has elapsed. [Other Embodiments] (a) In the above embodiment, a fixed value is used as the determination value td, but this value is changed according to the fluctuation of the outdoor temperature detected by the outdoor temperature detection unit 36 in FIG. It may be.
The magnitude of the power consumption when the dew condensation prevention operation is performed after the heating operation and the power consumption when the heating operation is continued also vary depending on the outdoor temperature. When the outdoor temperature is low, a large heating capacity is required to continue the heating operation and prevent dew condensation, so that continuing to heat for a long time is disadvantageous in terms of power consumption. Therefore, it is necessary to reduce the determination value td as the outdoor temperature is lower. Conversely, when the outdoor temperature is high, the determination value td may be increased. By setting an appropriate determination value td according to the outdoor temperature in this way, it is possible to reliably select an operation mode in which power consumption is reduced. (B) In the above embodiment, the waiting time ts is compared with the determination value td after the heating operation is stopped. However, when the heating operation is started after both the dew condensation prevention function and the heating ON timer are set by the remote controller, the heating operation is performed Ts may be compared with td. Alternatively, when both the condensation prevention function and the heating-on timer are set during the heating operation, the comparison may be performed at that time. (C) In the above embodiment, the operation time in the dew condensation prevention mode is set by the user, but the control unit automatically selects the time in consideration of the indoor temperature, the indoor humidity, the outdoor temperature, etc. immediately after the heating operation is stopped. You may make it. This eliminates the need for the user to select and set the time for the dehumidifying operation.
It is convenient for the user. (D) In the above embodiment, the operation in the cooling mode is selected as the dew condensation prevention mode, but a dry mode or a reheating dry mode may be selected. In such a case, the decrease in the room temperature does not become large as compared with the cooling mode. This is effective when there is no need to lower the room temperature during the dew condensation prevention operation.

[0032]

According to the present invention, when the dew condensation preventing function and the heating-on timer are set, and the heating operation is being performed, the next heating operation is started by the heating-on timer after the current heating operation is stopped. If the waiting time is shorter than the predetermined time, the heating operation is continued after the current heating operation is stopped until the next heating operation is started by the heating-on timer.
This prevents condensation without lowering the indoor temperature,
When the heating operation is started by the heating-on timer, it is easy to return the room temperature to an appropriate temperature, and the power consumption of the air conditioner can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an air conditioner to which an embodiment of the present invention is applied.

FIG. 2 is a configuration diagram of the refrigerant circuit.

FIG. 3 is a configuration diagram of the drive circuit.

FIG. 4 is a control block diagram thereof.

FIG. 5 is a flowchart thereof.

FIG. 6 is a flowchart thereof.

[Explanation of symbols]

 4 Condensation prevention means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3L060 AA03 CC02 CC03 CC08 DD07 EE01 3L061 BB04 BE03 BF08

Claims (7)

[Claims] An air conditioner comprising an indoor unit and an outdoor unit, wherein the indoor air is heated or cooled by an indoor heat exchanger disposed in the indoor unit, and the heated or cooled air is supplied indoors by an indoor fan to perform a cooling operation. Or, in the air conditioner equipped with the function of performing the heating operation and automatically stopping after performing the operation in the dew condensation prevention mode to prevent dew condensation on the walls and windows after the heating operation is stopped, the preset value is set in advance. If a heating-on timer that starts the heating operation after the elapse of the time is set, the waiting time until the next heating operation is started by the heating-on timer after the current heating operation is stopped is a predetermined determination value. If the waiting time is equal to or longer than the determination value, the operation is stopped after performing the operation in the dew condensation prevention mode for a certain period of time. An air conditioner provided with a dew condensation preventing means (4) for continuously operating in a heating mode instead of the air conditioner. 2. The air conditioner according to claim 1, wherein the determination value is changed based on an outdoor temperature. 3. The operation time in the dew condensation prevention mode is as follows.
The air conditioner according to claim 1, wherein the air conditioner can be set by a user. 4. A set temperature when operating in a heating mode instead of the dew condensation prevention mode is set to a temperature not lower than the dew point temperature calculated from the room temperature and the room humidity and as low as possible. The air conditioner according to claim 1. 5. The air conditioner according to claim 1, wherein the operation in the dew condensation prevention mode is a cooling operation. 6. An operation in the dew condensation prevention mode is a dry operation in which the indoor heat exchanger functions as a refrigerant evaporator to cool and dehumidify air and to reduce the airflow of the indoor fan from that in the cooling operation. The air conditioner according to any one of claims 1 to 4, wherein 7. The operation in the dew condensation prevention mode is such that a part of the indoor heat exchanger functions as a condenser and the other part functions as an evaporator, the indoor air is heated in the condenser, and the indoor air is heated in the evaporator. The air conditioner according to any one of claims 1 to 4, wherein the air conditioner is a reheating dry operation for cooling and dehumidifying.