JP2011158121A - Air conditioner - Google Patents

Abstract

An air conditioner capable of appropriately determining an abnormality in a refrigeration cycle is provided.
An air conditioner according to the present invention is formed by connecting a compressor 8, a four-way valve 9, an outdoor heat exchanger 10, a variable flow rate expansion valve 15, and an indoor heat exchanger 3 in this order. Refrigeration cycle, discharge temperature detection means 14 for detecting the discharge temperature of the refrigeration cycle, storage means 13 for storing the throttle opening and discharge temperature of the variable flow rate expansion valve, and the operating current value of the air conditioner And an operating current value storage means 13 for storing the expansion valve, wherein the expansion valve throttle opening is equal to or greater than a set value, and the discharge temperature detected by the discharge temperature detection means is equal to or greater than the discharge temperature set value. When the operating current value of the air conditioner is less than or equal to the operating current set value, the operation of the compressor is stopped.
[Selection] Figure 2

Description

  The present invention relates to an air conditioner, and more particularly to protection control of a compressor in a refrigeration cycle.

  In a conventional air conditioner, the compressor temperature is controlled as a compressor protection control in a state where the refrigerant in the refrigeration cycle is low, the refrigerant is exhausted, or is clogged somewhere in the refrigeration cycle. It is common to provide a compressor temperature sensor or discharge temperature sensor to protect against overheating and control the operation of the compressor based on those temperatures, or to incorporate an inner thermal protector inside the compressor. there were.

  However, the attachment of the sensor or the built-in protector has a problem that the manufacturing cost for attaching the sensor increases.

  On the other hand, in the conventional heat pump type air conditioner, the indoor piping temperature detecting means for detecting the condensation temperature of the refrigerant in the refrigeration cycle, the outdoor total operating current detecting means and the outdoor total operating current setting memory for controlling the refrigeration cycle. And a control device having an indoor pipe temperature setting storage means and a determination means, the control device is configured such that the outdoor total operating current is lower than the set value and the indoor pipe temperature exceeds the set temperature for a predetermined time during cooling operation. Alternatively, during the heating operation, the compressor is stopped when the indoor piping temperature falls below the set temperature for a predetermined time (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2003-329312

However, in the air conditioner having the above-described refrigeration cycle protection control, malfunctions or erroneous determinations may occur depending on the air conditioning conditions or operating conditions of the air conditioner installed with the refrigerant removed to some extent. Had problems.

  An object of this invention is to provide the air conditioner which can perform abnormality determination of a refrigerating cycle appropriately.

  In order to solve the above-described conventional problems, the air conditioner of the present invention is formed by annularly connecting a compressor, a four-way valve, an outdoor heat exchanger, a variable flow rate expansion valve, and an indoor heat exchanger in this order. Refrigeration cycle, discharge temperature detection means for detecting the discharge temperature of the refrigeration cycle, storage means for storing the throttle opening and discharge temperature of the variable flow rate expansion valve, and the operating current value of the air conditioner An air conditioner having an operating current value storage means for storing, wherein a throttle opening degree of the expansion valve is not less than a set value, and a discharge temperature detected by the discharge temperature detecting means is not less than a discharge temperature set value, and When the operating current value of the air conditioner is less than or equal to the operating current set value, the compressor operation is stopped to judge the refrigeration cycle abnormality, and the compressor operation is stopped to protect the compressor. Can be planned.

  The air conditioner of this invention can provide the air conditioner which can perform abnormality determination of a refrigerating cycle appropriately.

The circuit diagram of the air conditioner in Embodiment 1 of this invention Flowchart of the air conditioner in the first embodiment Flow chart of the air conditioner in the second embodiment Relationship diagram between outside temperature and operating current set value in the second embodiment Flow chart of the air conditioner in the third embodiment

  The air conditioner of the first invention includes a refrigeration cycle formed by annularly connecting a compressor, a four-way valve, an outdoor heat exchanger, a variable flow rate expansion valve, and an indoor heat exchanger in this order, and a refrigeration cycle Discharge temperature detecting means for detecting the discharge temperature, storage means for storing the throttle opening and discharge temperature of the variable flow rate expansion valve, and operating current value storage means for detecting and storing the operating current value of the air conditioner The expansion valve throttle opening is equal to or greater than a set value, the discharge temperature detected by the discharge temperature detecting means is equal to or greater than the discharge temperature set value, and the operating current value of the air conditioner is When the operating current is less than the set value, it is possible to protect the compressor by stopping the operation of the compressor by determining the abnormality of the refrigeration cycle and stopping the operation of the compressor.

  The air conditioner of the second invention comprises frequency detection means for detecting and storing the frequency of the compressor, and the frequency is controlled by performing the control of the first invention only when the frequency of the compressor is equal to or higher than a predetermined frequency. Even if the refrigeration cycle is normal when the temperature is low, malfunction is prevented by stopping the compressor by satisfying the conditions.

  In the air conditioner of the third invention, particularly in the first or second invention, the operating current set value is provided with two or more stages of operating current set values according to the outside air temperature, so that more accurate refrigeration is possible. The state of the cycle can be detected.

  The air conditioner according to a fourth aspect of the present invention is the air conditioner according to the first to third aspects of the present invention, in which the throttle opening degree of the expansion valve is not less than a set value and the discharge temperature detected by the discharge temperature detecting means is discharged for a predetermined time. When the temperature is over the set value and the operating current value of the air conditioner is below the operating current set value, the malfunction is prevented by delaying detection until the compressor operation is stabilized by stopping the compressor. be able to.

  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 is a circuit diagram of the air conditioner according to the first embodiment. As shown in FIG. 1, the air conditioner according to Embodiment 1 includes a compressor 8 that compresses refrigerant, a four-way valve 9 that switches a refrigerant flow path during cooling and heating, and heat exchange between the refrigerant and outside air. The refrigeration cycle is configured by connecting the outdoor heat exchanger 10 that performs the heat, the electric expansion valve 15 that decompresses the refrigerant, and the indoor heat exchanger 3 that performs heat exchange between the indoor air and the refrigerant in a ring shape through a refrigerant pipe. ing.

An indoor fan 4 is provided in the vicinity of the indoor heat exchanger 3 in order to promote heat exchange between the indoor air and the refrigerant in the indoor heat exchanger 3, and an outdoor air is provided in the vicinity of the outdoor heat exchanger 10. An outdoor fan 12, a fan motor 5 for driving the outdoor fan 12, a temperature sensor 6 for detecting the room temperature, an outdoor temperature sensor 11 for detecting the outdoor air temperature, and a compression A discharge temperature sensor 14 serving as a discharge temperature detecting means for detecting a discharge temperature from the machine, an indoor control device 7 for controlling the indoor unit 1 constituting the air conditioner, and an outdoor control device 13 for controlling the outdoor unit 2. And.

  In addition, it has storage means for storing the throttle opening and discharge temperature of the variable flow rate expansion valve, and operating current value storage means for detecting and storing the operating current value of the air conditioner. The outdoor control device 13 is provided. The air conditioner is controlled by the indoor control device 7 and the outdoor control device 13.

  Next, control of the air conditioner in the present embodiment will be described with reference to the flowchart of FIG.

  First, when the operation of the air conditioner starts in step 1, it is determined in step 2 whether or not the compressor 8 is operating. When the compressor 8 is operating in step 2, the current opening degree EXP of the expansion valve 15, the discharge temperature Td from the compressor 8, and the operating current value A of the air conditioner are supplied to the outdoor control device 13 in step 3. Remember.

  In step 4, when the current expansion valve opening EXP is larger than the preset set value exp1, and the refrigerant discharge temperature Td detected by the discharge temperature sensor 14 is the preset discharge temperature setting. If the value is larger than the value t1 and if the operating current value A is smaller than the operating current set value a1, the operation of the compressor is stopped in step 5.

  As described above, in this embodiment, even when the refrigerant is normally removed to some extent, the operation is performed to lower the discharge temperature by opening the expansion valve, and the refrigeration cycle such as the compressor does not become abnormal. When the outdoor load is high, the expansion valve opening becomes equal to or greater than the set opening, and the temperature of the refrigeration cycle cannot be controlled by the expansion valve, so the discharge temperature from the compressor cannot be lowered.

  Therefore, it is possible to determine the abnormality of the refrigeration cycle based on the expansion valve opening degree, the discharge temperature, and the operating current value, and to protect the motor coil and the compression mechanism from excessive temperature rise.

(Embodiment 2)
Since the circuit diagram of the air conditioner in the second embodiment is the same as that in the first embodiment, the same reference numerals as those in the first embodiment are given and description thereof is omitted. Next, control of the air conditioner in the present embodiment will be described with reference to the flowchart of FIG.

  First, when the operation of the air conditioner starts in step 1, it is determined in step 2 whether or not the compressor 8 is operating. If the compressor 8 is operating in step 2, the process proceeds to step 3.

  In step 3, the outdoor controller 13 as a frequency detecting means detects and stores the frequency CompHz of the compressor 8. In step 4, if the detected frequency CompHz is smaller than the set value Hz2, it is determined that the refrigerant state is normal, and the process returns to step 3. On the other hand, when the frequency CompHz detected in step 3 is larger than the set value Hz2, the process proceeds to step 5 where the current opening EXP of the expansion valve 15, the discharge temperature Td from the compressor 8, the operating current value of the air conditioner A is stored in the outdoor control device 13.

  When the current expansion valve opening EXP is larger than the preset set value exp2 in step 6, and the refrigerant discharge temperature Td detected by the discharge temperature sensor 14 is a preset discharge temperature setting. If the value is larger than the value t2 and if the operating current value A is smaller than the operating current set value a2, the operation of the compressor is stopped in step 7.

  As described above, in this embodiment, even when the refrigerant is normally removed to some extent, the operation is performed to lower the discharge temperature by opening the expansion valve, and the refrigeration cycle such as the compressor does not become abnormal. When the outdoor load is high, the expansion valve opening becomes equal to or greater than the set opening, and the temperature of the refrigeration cycle cannot be controlled by the expansion valve, so the discharge temperature from the compressor cannot be lowered.

  Furthermore, when the compressor frequency is low, even if the refrigeration cycle is normal, the expansion valve opening, discharge temperature, and operating current values all meet the conditions, causing malfunctions and stopping the compressor operation. End up.

  Therefore, since the malfunction condition is first excluded based on the frequency of the compressor, and the refrigeration cycle abnormality is judged based on the expansion valve opening, the discharge temperature, and the operating current value, the abnormality is more reliably detected. Thus, the motor coil and the compression mechanism can be protected from excessive temperature rise.

  In the present embodiment, the operating current set value a2 is set differently when the outside air temperature is lower than Ga and when the outside air temperature is higher than Ga. FIG. 4 shows the operating current set value a2 in the present embodiment. When a2 when the outside air temperature is lower than Ga is A21 and a2 when the outside air temperature is higher than Ga is A22, the relationship of A21 <A22 is established between A21 and A22.

  This is because when the outside air temperature is low, the outdoor heat exchanger 10 can secure a temperature difference between the refrigerant temperature and the outside air temperature, so that the air conditioner can be operated with a smaller operating current value. By determining the operating current set value a2 to be determined in accordance with the outside air temperature, it is possible to detect an accurate refrigeration cycle state.

  In the present embodiment, the operation current set value a2 is controlled in two stages. However, the present invention is not limited to this, and the control may be performed in two or more stages. In that case, a more accurate determination of abnormality in the refrigeration cycle can be performed.

(Embodiment 3)
Since the circuit diagram of the air conditioner in the third embodiment is the same as that in the first embodiment, the same reference numerals as those in the first embodiment are given and description thereof is omitted. Next, the control of the air conditioner according to the present embodiment will be described with reference to the flowchart of FIG. 5. First, when the operation of the air conditioner starts in step 1, it is determined in step 2 whether the compressor 8 is operating. To do. If the compressor 8 is operating in step 2, the process proceeds to step 3.

  In step 3, the timer counter that measures time is reset by the outdoor control device 13, and the operation time T <b> 1 from step 3 is measured.

  Then, the process proceeds to step 4 where the current opening degree EXP of the expansion valve 15, the discharge temperature Td from the compressor 8, and the operating current value A of the air conditioner are stored in the outdoor control device 13.

  In step 5, when the current expansion valve opening EXP is larger than the preset set value exp3, and the refrigerant discharge temperature Td detected by the discharge temperature sensor 14 is a preset discharge temperature setting. When the value is larger than the value t3 and when the operating current value A is smaller than the operating current set value a3, the process proceeds to Step 6, and when the condition is not satisfied, the process returns to Step 3.

  Then, in step 6, it is determined whether or not the operation time T1 from step 3 has exceeded a predetermined time Ts3 that has been set in advance. If not, the process returns to step 4. Stop driving. This is because the predetermined time Ts3 at which the discharge temperature of the compressor will be stabilized is obtained by experiment or the like, and the discharge temperature at the time of stability can be reliably used as the discharge temperature used for the determination of the abnormality of the refrigeration cycle. A more accurate refrigerant state can be detected.

  As described above, in the present embodiment, it is possible to more accurately determine the abnormality of the refrigeration cycle, and to protect the motor coil and the compression mechanism from excessive temperature rise.

  Note that the predetermined values exp1, exp2, exp3, t1, t2, t3, a1, a2, a3, Hz2, and Ts3 in the first to third embodiments are values determined from experiments or the like, and are uniquely determined. It is not a thing. That is, there is no problem in changing each predetermined value according to the configuration of the air conditioner.

  The air conditioner according to the present invention is optimal for controlling a separation type air conditioner separated into an indoor unit and an outdoor unit.

DESCRIPTION OF SYMBOLS 1 Indoor unit 2 Outdoor unit 3 Indoor heat exchanger 4 Indoor fan 5 Indoor fan motor 6 Indoor temperature sensor 7 Indoor controller 8 Compressor 9 Four-way valve 10 Outdoor heat exchanger 11 Outdoor temperature sensor 12 Outdoor fan 13 Outdoor controller 14 Discharge Temperature sensor 15 Electric expansion valve

Claims (4)

A refrigeration cycle formed by connecting a compressor, a four-way valve, an outdoor heat exchanger, a variable flow rate expansion valve, and an indoor heat exchanger in this order, and a discharge temperature detection for detecting the discharge temperature of the refrigeration cycle And an operating current value storage means for detecting and storing the operating current value of the air conditioner. The throttle opening of the expansion valve is not less than a set value, the discharge temperature detected by the discharge temperature detecting means is not less than the discharge temperature set value, and the operating current value of the air conditioner is not more than the operating current set value. In the case, the air conditioner is characterized in that the operation of the compressor is stopped. The air conditioner which has a frequency detection means which detects and memorize | stores the frequency of the said compressor, and performs the control of Claim 1 only when the frequency of the said compressor is more than predetermined frequency. The air conditioner according to claim 1 or 2, wherein the operating current set value is provided in two or more stages according to an outside air temperature. The throttle opening of the expansion valve is equal to or greater than a set value, and the discharge temperature detected by the discharge temperature detecting means is equal to or greater than the discharge temperature set value for a predetermined time, and the operating current value of the air conditioner is set to the operating current setting. The air conditioner according to any one of claims 1 to 3, wherein the compressor is stopped when the value is equal to or less than the value.

Images