JP2009174757A - Air conditioner and its operation control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability of a compressor in activation after recovery, and to shorten time of build up of air conditioning capacity. <P>SOLUTION: The compressor 3, a condenser 4, an expansion valve 5, and an evaporator 6 are sequentially connected by coolant piping to form a refrigerating cycle. The air conditioner is equipped with a control means 7 for controlling a valve opening of the expansion valve 5, and an electric power supplying means 8 for supplying auxiliary electric power to the control means 7 during power failure. In the control means 7, when it is detected that supply of driving electric power to the compressor 3 has stopped, the auxiliary electric power is obtained from the electric power supplying means 8 and a close signal of fully closing the valve opening of the expansion valve 5 is outputted. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air conditioner and an operation method thereof.

  In the conventional air conditioner, when the operation of the refrigeration cycle is stopped due to a power failure or the like, the operation is automatically restarted after the power recovery according to the storage of the operation state before the stop. For example, an air conditioner is disclosed in which the drive frequency of a compressor driven by an inverter is recorded during operation before a power failure, and when the power is restored and the operation is resumed, the drive frequency before the power failure is a target frequency. (See Patent Document 1). According to this, it is possible to return the air conditioning capability to the state before the power failure in a short time, and it is possible to adapt to changes in the air conditioning load.

  Further, in the technique of Patent Document 1, only when the compressor surface temperature at the time of power recovery is higher than the set temperature, the compressor drive frequency stored during operation is set to the target frequency and the operation is resumed. The air conditioner which did is disclosed (refer patent document 2). According to this, for example, the target frequency after power recovery can be appropriately set according to the stop time due to a power failure.

JP-A-7-332774 JP-A-10-9687

  By the way, for example, in the air conditioner of Patent Document 1, when an electronic expansion valve is provided in the refrigeration cycle, if a power failure occurs during operation of the air conditioner, the electronic expansion valve stops in an open state with the opening during operation. To do. For this reason, depending on the indoor and outdoor temperature conditions (temperature difference, etc.), a phenomenon occurs in which the refrigerant moves in the refrigeration cycle during a power failure. That is, since the refrigerant has a characteristic of moving to the low temperature side, it moves to the indoor side when the room is cooler than the outdoor side, and conversely, moves to the outdoor side when the outdoor temperature is lower than the indoor side. .

  Here, in an air conditioner in which a compressor and an evaporator are mounted on an indoor unit, if a power failure occurs during cooling operation, for example, if the indoor temperature is lower than the outdoor temperature, the refrigerant moves to the indoor side. When the compressor is started by power recovery, the liquid refrigerant accumulated in the evaporator is not directly evaporated and is directly sucked into the compressor. As a result, liquid compression occurs, and the compressor may be defective. Also, when the temperature outside the room is lower than the room temperature, when the compressor is started, for example, the refrigerant accumulated outside the room moves via the expansion valve and the evaporator and is supplied to the compressor. If the supply of refrigerant to the machine is delayed, the compressor that cannot obtain the cooling effect of the refrigerant may cause overheating damage, or even if the compressor is not damaged, the rise of the cooling capacity at the start-up may be delayed. is there.

  This invention makes it a subject to improve the reliability of the compressor at the time of starting after a power recovery, and shorten the rise time of an air-conditioning capability.

  In order to solve the above problems, the present invention controls a valve opening degree of an expansion valve in an air conditioner in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe to form a refrigeration cycle. And a power supply means for supplying reserve power to the control means in the event of a power failure. The control means obtains reserve power from the power supply means and expands when the supply stop of the compressor drive power is detected. A closing signal that outputs the valve opening degree of the valve to a fully closed state is output.

  According to this structure, even if supply of the drive power of a compressor stops temporarily by a power failure etc., the valve opening degree of an expansion valve can be made into a fully closed state. Then, by closing the expansion valve and blocking the refrigerant flow path in this way, the movement of the refrigerant in the refrigeration cycle can be restricted and the balance of the refrigerant amount can be maintained. As a result, the space on the suction side of the compressor, for example, the inside of the evaporator, can maintain the refrigerant amount within a predetermined range even in the event of a power failure. The compressor can be prevented from being damaged by sucking and liquid-compressing, and the reliability of the compressor can be improved. Moreover, since the time until the refrigerant is sucked into the compressor after the power recovery can be shortened, the rise time of the air conditioning capability can be shortened.

  In this case, the control means has storage means for storing the valve opening degree of the expansion valve before the power failure, and when the drive power supply recovers, reads the valve opening degree of the expansion valve before the power failure from the storage means, An open signal with the read valve opening is output to the expansion valve.

  According to this, since it can be restarted in the operating state before the power failure, it can be returned to the normal refrigeration capacity state in a short time, and the transient control change after the restart can be suppressed. it can.

  Further, according to the present invention, in the operation control method for an air conditioner in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe to form a refrigeration cycle, the supply of compressor drive power is stopped. At this time, the refrigerant flow path between the condenser and the evaporator is shut off until the drive power is restored.

  That is, as long as the refrigerant flow path between the condenser and the evaporator is cut off, the method is not limited to the method of fully closing the valve opening of the expansion valve. For example, a valve other than the expansion valve is provided in the refrigerant flow path. The effect of the present invention can also be obtained by providing and controlling the valve to be closed from the outside.

  ADVANTAGE OF THE INVENTION According to this invention, while improving the reliability of the compressor at the time of starting after a power recovery, the rise time of air-conditioning capability can be shortened.

  Hereinafter, a first embodiment of an air conditioner to which the present invention is applied will be described with reference to the drawings.

  FIG. 1 is a configuration diagram showing the overall configuration of an air conditioner to which the present invention is applied. The air conditioner of this embodiment comprises a refrigerating cycle by connecting the indoor unit 1 and the outdoor unit 2 with the refrigerant | coolant piping 9. FIG. The indoor unit 1 is equipped with a compressor 3, an electronic expansion valve 5, an evaporator 6, a control device 7, and a power supply device 8, and the outdoor unit 2 is equipped with a condenser 4. The refrigeration cycle is provided with a four-way valve (not shown) that switches the flow of the refrigerant in accordance with switching of the cooling / heating operation. A backflow prevention valve is provided at the suction port of the compressor 3.

  The control device 7 is electrically connected to the compressor 3 and the electronic expansion valve 5, respectively, and outputs various signals to the compressor 3 and the electronic expansion valve 5, for example, based on the operating frequency determined by the cooling load. These operations are controlled. A power supply device 8 is electrically connected to the control device 7 so that predetermined power is supplied to the control device 7 in the event of a power failure. Here, the electronic expansion valve 5 is a valve whose opening can be freely controlled by an external electric signal. For example, the electronic expansion valve 5 can be controlled by any signal such as a start signal for the compressor 3. Can do.

  In such a configuration of the air conditioner, an operation during cooling operation will be described as an example. The high-temperature and high-pressure gas refrigerant discharged from the compressor 3 is guided to the condenser 4 and exchanges heat with the outside air to become a liquid refrigerant. The liquid refrigerant that has passed through the condenser 4 is guided to the electronic expansion valve 5 and expanded, and then sent to the evaporator 6 to evaporate by exchanging heat with room air to become a gas refrigerant. The gas refrigerant that has passed through the evaporator 6 is sucked into the compressor 3 and compressed again, and circulates in the refrigeration cycle described above. The room air cooled by exchanging heat with the refrigerant in the evaporator 6 is blown out into the room for cooling.

  In the present embodiment, for example, when a power failure occurs and supply of electric power for operating the refrigeration cycle is suddenly stopped, reserve power is obtained from the power supply device 8 and the control device 7 sends a predetermined control signal to the electronic expansion valve 5. By outputting, the valve opening degree of the electronic expansion valve 5 is controlled.

  Here, in order to explain the operation of the present embodiment in an easy-to-understand manner, a conventional refrigeration cycle that does not have the power supply device 8 and does not control the valve opening degree of the electronic expansion valve 5 at the time of a power failure will be described. The operation will be described.

  In the conventional air conditioner, when a power failure occurs during the operation of the refrigeration cycle, the compressor 3 stops driving, and the electronic expansion valve 5 stops with the valve open at the opening just before the power failure occurs. During this power failure, for example, when the room is in a high temperature state (for example, 30 ° C., the same applies hereinafter) and the outdoor is in a low temperature state (for example, 10 ° C., the same applies hereinafter), the electronic expansion valve 5 is open, so The refrigerant in the vessel 6 passes through the electronic expansion valve 5 and moves to the low-temperature condenser 4 side.

  In this way, when the refrigerant is biased toward the outdoor side, that is, the condenser side 4, when the compressor 3 is activated by power recovery, the refrigerant passes through the condenser 4, the electronic expansion valve 5, and the evaporator 6. Since the refrigerant is supplied into the compressor 3, the cooling capacity is not exhibited until the refrigerant is supplied into the compressor 3, and the cooling effect by the refrigerant of the compressor 3 does not occur. The reliability of the machine 3 may be impaired.

  On the other hand, during a power outage, when the temperature deviation between the room and the room is opposite to the above, that is, when the room is at a low temperature and the room is at a high temperature, the refrigerant moves to the evaporator 6 side. In this way, when the compressor 3 is activated by power recovery in a state where a large amount of refrigerant exists in the evaporator 6, liquid refrigerant that could not be evaporated in the evaporator 6 is supplied into the compressor 3. Therefore, the cooling ability is not exhibited, and the reliability of the compressor 3 may be impaired due to liquid compression.

  In contrast, in the air conditioner of the present embodiment, when a power failure occurs during the cooling operation, first, the control device 7 detects the supply stop of the driving power of the compressor 3 and has been in a standby state until then. Power is supplied from the power supply device 8 to the control device 7. The control device 7 consumes the electric power obtained from the power supply device 8 and performs control to output a closing signal for fully closing the valve to the electronic expansion valve 5. As a result, the electronic expansion valve 5 is fully closed, the refrigerant pipe connecting the condenser 4 and the evaporator 6 through the electronic expansion valve 5 is blocked, and the movement of the refrigerant is restricted. .

  By closing the electronic expansion valve 5 in this way, the distribution (balance) of the refrigerant amount is maintained in a normal operation state even during a power failure in the refrigeration cycle. Accordingly, when the room is in a high temperature state and the outdoor is in a low temperature state at the time of a power failure, for example, the refrigerant in the evaporator 6 does not move to the condenser 4 side through the electronic expansion valve 5. After restarting with electricity, the refrigerant is supplied to the compressor 3 in a short time. Therefore, the cooling capacity can be reached to the level of the normal operation state in a short time. In addition, since an appropriate amount of refrigerant is supplied to the compressor 3 in a short time after restarting, the cooling effect of the refrigerant can be obtained in a short time, and heat damage to the compressor 3 can be prevented to improve reliability. Can do.

  On the other hand, when the room is at a low temperature and the outside is at a high temperature, the refrigerant does not pass through the electronic expansion valve 5 and move to the evaporator 6 side. Therefore, after the restart, the refrigerant is evaporated in the evaporator 6. Since the gas state is supplied to the compressor 3, the cooling capacity can be exhibited in a short time. Moreover, since the damage of the compressor 3 by liquid compression can be prevented, the reliability of the compressor 3 can be improved.

  FIG. 2 is a time chart showing the transition of cooling capacity recovery after power recovery in the air conditioner of the present embodiment and the prior art air conditioner, with the horizontal axis representing time and the vertical axis representing cooling capacity. . According to the present embodiment (first example), it is possible to shorten the time required to return to the cooling capacity in the operating state before the power failure as compared with the prior art.

  In this embodiment, since the operation of the control device 7 at the time of a power failure is covered by the power supply device 8, the power supply device 8 only needs to store power for fully closing the electronic expansion valve 5. In the present embodiment, an example is shown in which the power supply device 8 is disposed outside the control device 7. However, the present invention is not limited to this. It may be.

  Next, a second embodiment of an air conditioner to which the present invention is applied will be described.

  In the present embodiment, in addition to the configuration of the first embodiment, the control device 7 includes the following control. That is, in the present embodiment, a function for storing the valve opening degree of the electronic expansion valve 5 before the power failure in a memory in the microcomputer is built in, for example, the control device 7, and power is restored to resume the operation of the refrigeration cycle. Sometimes, the valve opening memorized before the power failure is read from the memory, and the opening signal is controlled to be output from the control device 7 to the electronic expansion valve 5 so that the electronic expansion valve 5 becomes the read valve opening. .

  In this way, by returning the valve opening of the electronic expansion valve 5 to the same state as before the power failure, in addition to the effect of the first embodiment, as shown in the second example of FIG. It becomes possible to return the freezing capacity later to the state before the power failure in a shorter time. Moreover, since it can start in the state before a power failure, the transitional control change after restart can be suppressed.

  In the embodiment described above, the operation at the time of power recovery during the cooling operation has been described as an example, but the same effect can be obtained also during the heating operation. In the refrigeration cycle, the compressor 3 and the electronic expansion valve 5 are both mounted in the indoor unit 1. However, the present invention is not limited to this, and these are mounted in the indoor unit 2. However, the same effect can be obtained.

  Furthermore, the present invention is not limited to a one-to-one refrigeration cycle in which a condenser or an evaporator is used. For example, a plurality of indoor units are connected to one outdoor unit by a refrigerant pipe. A multi-type air conditioner that constitutes a refrigeration cycle can also be applied.

It is a block diagram which shows the whole structure of the air conditioner to which this invention is applied. It is a time chart which shows transition of the recovery | restoration of the cooling capacity after a power recovery in the air conditioner of this embodiment and the air conditioner of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Indoor unit 2 Outdoor unit 3 Compressor 4 Condenser 5 Electronic expansion valve 6 Evaporator 7 Control apparatus 8 Electric power supply apparatus 9 Refrigerant piping

Claims (3)

In an air conditioner that forms a refrigeration cycle by sequentially connecting a compressor, a condenser, an expansion valve, and an evaporator with refrigerant piping,
Control means for controlling the valve opening of the expansion valve, and power supply means for supplying reserve power in the event of a power failure to the control means,
When the supply of the drive power of the compressor is detected, the control means obtains reserve power from the power supply means and outputs a closing signal for fully opening the valve opening of the expansion valve. A featured air conditioner. In the air conditioner according to claim 1,
The control means has storage means for storing a valve opening degree of the expansion valve before the power failure, and reads the valve opening degree of the expansion valve before the power failure from the storage means when the drive power supply is restored. An air conditioner that outputs an open signal with the read valve opening to the expansion valve. In the operation control method of an air conditioner in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe to form a refrigeration cycle.
An air conditioner that shuts off a refrigerant flow path between the condenser and the evaporator until the drive power is restored when supply of the drive power to the compressor is stopped. Operation control method.

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