JP5460692B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner that performs a cooling operation or a heating operation using a refrigeration cycle, and in particular, appropriately controls a throttling mechanism that is one of the components of the refrigeration cycle so that an appropriate refrigeration cycle can be maintained. The present invention relates to an air conditioner.

  Conventionally, there is an air conditioner provided in the event of a power failure. As such, “at least one variable capacity compressor, heat source side heat exchanger, expansion valve, and use side heat exchanger are sequentially connected in an annular manner by pipe connection in an annular fashion. In the apparatus, an operation state detection unit that detects an operation state of a predetermined device including at least a compressor and an expansion valve held by the refrigerant circuit, and an operation state storage unit that stores the operation state detected by the operation state detection unit And a power failure detection means for detecting power supply and power failure of the power supplied to the refrigerant circuit, and when the occurrence of a power failure and subsequent resumption of power supply is detected by the power failure detection means, the operation state storage means stores the power failure. An air conditioner provided with predetermined device control means for controlling the predetermined device by setting the operation state before the power failure as a control target value has been proposed (for example, see Patent Document 1). .

  In such an air conditioner, when a power failure occurs, the command amount to the throttle mechanism and the actual control amount of the throttle mechanism often differ. Therefore, in the conventional technique, after the air conditioner is restored, the control amount of the throttle mechanism is initialized so that the command amount and the control amount of all the throttle mechanisms are matched. Therefore, during the operation of initializing the throttle mechanism, the operation of the air conditioner cannot be resumed and has been stopped. However, if it is required to perform quickly after the air conditioner is restored, the initialization of some or all of the throttle mechanisms can be omitted, and the command amount and control amount can be left unmatched. Continued driving.

JP 2007-255759 A (4th, 5th page, FIG. 1, FIG. 2 etc.)

  In a conventional control method for a throttle mechanism such as an air conditioner, the difference between the command amount and the control amount of the throttle mechanism increases each time the air conditioner fails, and the refrigeration cycle after power recovery is optimized for refrigeration. It could take a lot of time to reach the cycle. Therefore, the refrigeration cycle after power recovery cannot quickly exhibit a predetermined capacity. In addition, if the operation is continued without matching the command amount and the control amount of the aperture mechanism, there is a possibility that the device may break down.

  The present invention has been made to solve the above problems, and provides an air conditioner that can be started in a short time after power recovery and that can maintain an optimum refrigeration cycle in a short time. The purpose is that.

An air conditioner according to the present invention includes a compressor, a heat source side heat exchanger, a high pressure side of a supercooling heat exchanger, a first throttle mechanism, and a main refrigerant circuit in which a use side heat exchanger is connected in series, A bypass circuit branched between the supercooling heat exchanger and the first throttle mechanism, and connected to the suction side of the compressor via the second throttle mechanism and the low pressure side of the supercooling heat exchanger; A time ΔT from when a power failure occurs in the air conditioner and when an opening command is given to the first throttle mechanism and the second throttle mechanism until the power failure occurs And comparing the required time T1 until the command amount of the opening degree with respect to the first throttle mechanism and the second throttle mechanism and the actual control amount of the opening degree coincide with each other after the power recovery, A controller for correcting a command amount of the opening degree for the second throttle mechanism; Control unit, opening to said first diaphragm mechanism and the allowable range of the control amount of the actual opening relative to the second diaphragm mechanism, and, once that the generated power outage the first throttle mechanism and the second throttle mechanism From the difference between the command amount and the control amount of the actual opening, the number of power outages that can be permitted without initializing the first throttle mechanism and the second throttle mechanism is stored in advance as a specified number of times. If less than the prescribed number of times is previously stored, when the one of the first throttle mechanism and the second throttle mechanism is initialized, the number of power outages is the prescribed number of times or more which is stored in advance The other of the first diaphragm mechanism and the second diaphragm mechanism is initialized to correct the command amount of the opening for the first diaphragm mechanism and the second diaphragm mechanism .

  The air conditioner according to the present invention can be started in a short time after power recovery, and an optimum refrigeration cycle can be maintained in a short time.

3 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus according to Embodiment 1. FIG. It is a graph which shows the relationship between the control amount of a 2nd aperture mechanism, and the change of a refrigerating cycle. It is a graph which shows the relationship between the control amount of the 2nd aperture mechanism at the time of a power failure, and time. It is a flowchart which shows the flow of a process about initialization of the aperture mechanism at the time of a power failure occurrence. 6 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of an air-conditioning apparatus according to Embodiment 2. FIG. It is a flowchart which shows the flow of a process about correction | amendment of the instruction | command amount of the aperture mechanism at the time of a power failure generation | occurrence | production. 6 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of an air-conditioning apparatus according to Embodiment 3. FIG. It is a graph which shows the relationship between the control amount of an aperture mechanism, and a superheat degree. It is a flowchart which shows the flow of a process about correction | amendment of the instruction | command amount of the aperture mechanism at the time of a power failure occurrence.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Heat source side heat exchanger, 4 Supercooling heat exchanger, 5 1st throttle mechanism, 6 Use side heat exchanger, 7 Accumulator, 8 2nd throttle mechanism, 9 Power part, 50 Control unit, 51 power supply detection means, 52 storage device, 52a storage device, 52b storage device, 61 high pressure sensor, 62 low pressure sensor, 65 first temperature sensor, 66 second temperature sensor, 100 air conditioner, 200 air conditioner, 300 Air conditioner.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of an air-conditioning apparatus 100 according to Embodiment 1 of the present invention. Based on FIG. 1, the refrigerant circuit structure and operation | movement of the air conditioning apparatus 100 are demonstrated. The air conditioner 100 performs a cooling operation or a heating operation using a refrigeration cycle (heat pump cycle) for circulating a refrigerant. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

  The air conditioner 100 includes a compressor 1, a four-way valve 2, a heat source side heat exchanger 3, a high pressure side flow path of the supercooling heat exchanger 4, a first throttle mechanism 5, a use side heat exchanger 6, and an accumulator. The main refrigerant circuit which connected 7 in series with refrigerant piping is provided. Further, the air conditioner 100 branches the refrigerant pipe on the downstream side of the supercooling heat exchanger 4 (downstream side in the refrigerant flow direction during the cooling operation), and the second throttle mechanism 8 and the supercooling heat exchanger 4 A bypass circuit is provided for joining the refrigerant pipe connecting the four-way valve 2 and the accumulator 7 via the low-pressure channel.

  The compressor 1 compresses the sucked low-temperature / low-pressure refrigerant, discharges it as a high-temperature / high-pressure refrigerant, and enables the air-conditioning operation by circulating the refrigerant in the system. The compressor 1 is generally configured as a type capable of frequency control by an inverter, but may be a type having a constant rotation speed. The four-way valve 2 switches the refrigerant flow path between the cooling operation and the heating operation. That is, by controlling the four-way valve 2, the flow direction of the refrigerant flowing through the refrigerant circuit is reversed in the cooling operation and the heating operation.

  The heat source side heat exchanger 3 functions as a condenser (radiator) during cooling operation, and as an evaporator during heating operation, and heat-exchanges with surrounding air to condense or liquefy the refrigerant. is there. The heat source side heat exchanger 3 is generally configured together with a fan (not shown), and the condensation capacity or the evaporation capacity is controlled by the rotational speed of the fan. The supercooling heat exchanger 4 exchanges heat between the refrigerant flowing through the main refrigerant circuit (high pressure side) and the refrigerant flowing through the bypass circuit (low pressure side), and subcools the refrigerant flowing through the main refrigerant circuit, It has a function of stabilizing the control of the one diaphragm mechanism 5. The supercooling heat exchanger 4 is typically a double pipe structure, but is not limited to this, and may be a plate heat exchanger.

  The first throttle mechanism 5 has a function as a pressure reducing valve or an expansion valve, and decompresses the refrigerant to expand it. The first throttle mechanism 5 is configured with a valve whose opening degree can be variably controlled, for example, a typical electronic expansion valve. The use-side heat exchanger 6 functions as an evaporator during cooling operation and as a condenser (heat radiator) during heating operation, and exchanges heat between refrigerant and air (air supplied from a fan not shown). The refrigerant is evaporated and gasified or condensed.

  The accumulator 7 is installed on the suction side of the compressor 1 and is for storing surplus refrigerant generated depending on the operation state. In the first embodiment, the case where the accumulator 7 is provided will be described as an example. However, the present invention is not limited to this. For example, the accumulator 7 may not be provided, and a liquid receiver (receiver) may be provided between the heat source side heat exchanger 3 and the supercooling heat exchanger 4. Moreover, you may make it provide both the accumulator 7 and a liquid receiver. The second throttle mechanism 8 functions as a pressure reducing valve or an expansion valve, and expands the refrigerant by reducing the pressure. The second throttle mechanism 8 is configured by a valve whose opening degree can be variably controlled, for example, a typical electronic expansion valve.

  The air conditioner 100 includes a control unit 50 that performs overall control of the air conditioner 100. The control unit 50 commands the first throttle mechanism 5 and the second throttle mechanism 8 to a specific throttle opening, and initializes the throttle openings of the first throttle mechanism 5 and the second throttle mechanism 8. It has. Moreover, the control part 50 is also performing the control of the drive frequency of the compressor 1, and the switching control of the four-way valve 2 according to a driving | running state or every mode. That is, the control unit 50 controls each actuator (the compressor 1, a fan (not shown), the first throttle mechanism 5, the second throttle mechanism 8, and the four-way valve 2) based on an operation instruction from the user. It has become.

  In addition, the air conditioner 100 includes power detection means 51 that can detect the power supply voltage of the power unit 9 to detect a power failure / recovery. The power source detection means 51 may be any device that can detect a power failure / recovery by detecting the power source voltage of the power unit 8 connecting the compressor 1 and the local power source. The detection means 51 may be attached to an electrical component other than the power unit 9 of the compressor 1. The air conditioner 100 further includes a storage device 52 that can store information on the number of times of power failure / recovery detected by the power source detection means 51. The storage device 52 may be composed of a nonvolatile memory such as a flash memory. Note that the storage device 52 may be built in the control unit 50.

  Examples of the refrigerant used in the air conditioner 100 include a non-azeotropic refrigerant mixture, a pseudo-azeotropic refrigerant mixture, and a single refrigerant. Non-azeotropic refrigerant mixture includes R407C (R32 / R125 / R134a) which is an HFC (hydrofluorocarbon) refrigerant. Since this non-azeotropic refrigerant mixture is a mixture of refrigerants having different boiling points, it has a characteristic that the composition ratio of the liquid-phase refrigerant and the gas-phase refrigerant is different. The pseudo azeotropic refrigerant mixture includes R410A (R32 / R125) and R404A (R125 / R143a / R134a) which are HFC refrigerants. This pseudo azeotrope refrigerant has the same characteristic as that of the non-azeotrope refrigerant and has an operating pressure of about 1.6 times that of R22.

  The single refrigerant includes R22, which is an HCFC (hydrochlorofluorocarbon) refrigerant, R134a, which is an HFC refrigerant, and the like. Since this single refrigerant is not a mixture, it has the property of being easy to handle. In particular, it has been pointed out that HCFC refrigerants such as refrigerant R22, which have been used in conventional air conditioners, have a higher ozone depletion coefficient than the HFC refrigerant and have a large adverse environmental impact. From such a background, the transition to refrigerants having a small ozone depletion coefficient such as HFC refrigerants and natural refrigerants is progressing.

  The refrigerant flow in the cooling mode will be described. The air conditioner 100 can perform a cooling operation or a heating operation based on an instruction from a user. When the air conditioning apparatus 100 performs the cooling operation, the control unit 50 switches the four-way valve 2 so that the high-temperature / high-pressure refrigerant discharged from the compressor 1 flows into the heat source side heat exchanger 3. In this state, the operation of the compressor 1 is started. The control unit 50 controls the opening degree of the first diaphragm mechanism 5 and the second diaphragm mechanism 8, and the control amount will be described with reference to FIG.

  The high-temperature and high-pressure refrigerant gas discharged from the compressor 1 flows into the heat source side heat exchanger 3 via the four-way valve 2. The refrigerant gas flowing into the heat source side heat exchanger 3 is condensed and liquefied by air supplied from a fan (not shown). The condensed and liquefied high-pressure refrigerant flows through the high-pressure side flow path of the supercooling heat exchanger 4. A part of the refrigerant flowing out from the supercooling heat exchanger 4 flows into the bypass circuit side. The refrigerant that has flowed into the bypass circuit is decompressed and expanded by the second throttle mechanism 8 and becomes a low-pressure refrigerant. This refrigerant flows through the low-pressure side flow path of the supercooling heat exchanger 4. At this time, in the supercooling heat exchanger 4, the high-pressure refrigerant flowing through the high-pressure side passage and the low-pressure refrigerant flowing through the low-pressure side passage exchange heat.

  Therefore, the high-pressure refrigerant flowing through the high-pressure channel is further cooled by the low-pressure refrigerant flowing through the low-pressure channel, and the degree of supercooling increases. The high-pressure refrigerant cooled by the supercooling heat exchanger 4 is decompressed by the first throttle mechanism 5 and expands to become a low-pressure refrigerant and flows into the use side heat exchanger 6. The low-pressure refrigerant flowing into the use side heat exchanger 6 is evaporated and gasified with air supplied from a fan (not shown). The low-pressure refrigerant that has been evaporated and gasified passes through the four-way valve 2 and joins the low-pressure refrigerant that has flowed through the bypass circuit and the accumulator 7 upstream, and flows into the accumulator 7. Then, it is sucked again into the compressor 1.

  FIG. 2 is a graph showing the relationship between the control amount (throttle opening) of the second throttle mechanism 8 and the change of the refrigeration cycle (refrigerant state transition). A change in the refrigeration cycle based on the control amount of the second throttle mechanism 8 will be described with reference to FIG. In FIG. 2, the horizontal axis represents the control amount of the second throttle mechanism 8, and the vertical axis represents the change in the refrigeration cycle (refrigerant state). In FIG. 2, the control amount of the second diaphragm device 8 is shown as an example, but the control amount of the first diaphragm device 5 can be described in the same manner.

  In the cooling mode executed by the air conditioner 100, as described above, the refrigerant that has flowed into the bypass circuit is decompressed and expanded by the second throttle mechanism 8, becomes a low-pressure refrigerant, and the low-pressure of the supercooling heat exchanger 4. It flows into the side channel. When the throttle opening of the second throttle mechanism 8 is smaller than the optimum value (the appropriate range shown in FIG. 2) (the excessive range shown in FIG. 2), the heat quantity with the high-pressure refrigerant is insufficient in the supercooling heat exchanger 4. However, the degree of supercooling is small, the degree of supercooling is insufficient, and the capacity of the air conditioner 100 is reduced. In addition, when the throttle opening of the second throttle mechanism 8 is further reduced, the high pressure of the refrigerant may increase excessively and reach an abnormally high pressure.

  On the contrary, when the throttle opening of the second throttle mechanism 8 is larger than the optimum value (excessive range shown in FIG. 2), the refrigerant condensed and liquefied by the heat source side heat exchanger 3 is passed through the bypass circuit to the accumulator. 7 will flow excessively. If it does so, the capability of the air conditioning apparatus 100 will fall again because the liquid back amount to the compressor 1 becomes excessive or the degree of supercooling becomes insufficient.

  FIG. 3 is a graph showing the relationship between the control amount of the second aperture mechanism 8 and time during a power failure. A time-dependent difference between the command amount of the second aperture mechanism 8 and the control amount that occurs at the time of a power failure will be described with reference to FIG. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the opening degree of the second expansion device 8. In FIG. 3, the control amount of the second aperture mechanism 8 at the time of a power failure is shown as an example, but the control amount of the first aperture device 5 at the time of a power failure can be described in the same manner.

  When a command for the throttle opening degree is transmitted from the command unit of the control unit 50 to the second throttle device 8, the actual control amount of the second throttle device 8 becomes the transmitted command amount. However, a predetermined time T1 is required until the actual control amount reaches the command amount. If a power failure occurs during this time T1, power will not be supplied to the second diaphragm device 8, and a difference between the actual control amount and the command amount will occur. In FIG. 3, the difference between the actual control amount and the command amount generated by one power failure is shown as Sj.

A method of calculating the difference Sj between the command amount and the control amount of the aperture mechanism (the first aperture mechanism 5 and the second aperture mechanism 8) will be described with reference to FIG.
The throttle opening width per unit time of the throttle mechanism is ΔSj, the required time until the command amount and the control amount coincide with each other, T1, the power failure occurs, and from the time when the command is issued from the command section until the power failure occurs The difference Sj between the command amount and the control amount can be calculated by the following equation.

  FIG. 4 is a flowchart showing the flow of processing for initializing the aperture mechanism (the first aperture device 5 and the second aperture device 8) when a power failure occurs. Based on FIG. 4, initialization of the throttle mechanism when a power failure occurs, which is a characteristic matter of the air-conditioning apparatus 100 according to Embodiment 1, will be described. From the allowable range of the control amount of the aperture mechanism, the command amount generated by a single power failure, and the difference Sj between the control amounts, the number of power failures that can be permitted without initializing the aperture mechanism is stored in advance in the storage device 52 as the specified number of times. Keep it.

  When a power failure / recovery occurs (step S1), the control unit 50 reads the number of power failures from the storage device 52, counts +1, writes the number of power failures counted +1 to the storage device 52, and counts up the number of power failures. Execute (Step S2). Then, the control unit 50 compares the number of power outages with a predetermined number stored in advance (step S3). When the number of power failures is less than the specified number (step S3; Yes), the control unit 50 initializes only the first aperture mechanism 5 (step S4). On the other hand, when the number of power failures is equal to or greater than the prescribed number (step S3; No), the control unit 50 initializes only the second aperture mechanism 8 (step S5). Thus, since the throttle mechanism is initialized, the initialization time can be maintained in a short time, and an optimum refrigeration cycle can be maintained. The initialization of the first aperture mechanism 5 and the second aperture mechanism 8 may be reversed.

  As described above, the air conditioner 100 includes at least the compressor 1, the heat source side heat exchanger 3, the plurality of throttle mechanisms (the first throttle mechanism 5 and the second throttle mechanism 8), and the use side heat exchanger 6. The controller 50 includes a controller 50 that compares the number of times of power failure with a predetermined predetermined number of times, and determines whether or not to initialize a plurality of aperture mechanisms after power recovery. Specifically, in the air conditioner 100, the compressor 1, the heat source side heat exchanger 3, the high pressure side of the supercooling heat exchanger 4, the first throttle mechanism 5, and the use side heat exchanger 6 are connected in series. Branching between the main refrigerant circuit, the supercooling heat exchanger 4 and the first throttle mechanism 5, and the suction side of the compressor 1 through the second throttle mechanism 8 and the low pressure side of the supercooling heat exchanger 4 And a bypass circuit connected to.

  The control unit 50 initializes the first diaphragm mechanism 5 or the second diaphragm mechanism 8 when the number of power outages is less than the specified number of times, and the first diaphragm mechanism 5 and the second diaphragm mechanism when the number of power outages is equal to or greater than the specified number of times. The one that was not initialized among 8 is initialized.

Embodiment 2. FIG.
FIG. 5 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus 200 according to Embodiment 2 of the present invention. Based on FIG. 5, the refrigerant circuit structure and operation | movement of the air conditioning apparatus 200 are demonstrated. The air conditioner 200 performs a cooling operation or a heating operation using a refrigeration cycle in which a refrigerant is circulated. In the second embodiment, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment are denoted by the same reference numerals.

  The air conditioner 200 differs from the air conditioner 100 according to Embodiment 1 in the function of the storage device (hereinafter referred to as the storage device 52a) and the method of correcting the command amount of the throttle mechanism. The storage device 52a stores the command amount from the command unit immediately before the occurrence of the power failure and the time from when the command is issued until the power failure occurs when the power failure occurs. The storage device 52a may be composed of a nonvolatile memory such as a flash memory. The storage device 52a may be built in the control unit 50. In addition, the refrigerant flow in the cooling mode of the air-conditioning apparatus 200 according to Embodiment 2 and the relationship between the opening of the throttle mechanism and the change in the refrigeration cycle are the same as those of the air-conditioning apparatus 100 according to Embodiment 1. is there.

  FIG. 6 is a flowchart showing the flow of processing for correcting the command amount of the aperture mechanism (the first aperture device 5 and the second aperture device 8) when a power failure occurs. Based on FIG. 6, correction of the command amount of the throttle mechanism when a power failure occurs, which is a feature of the air-conditioning apparatus 200 according to Embodiment 2, will be described. As described with reference to FIG. 3, the time required for the command amount and the control amount to coincide with each other is T1, and the time from when the power failure occurs to when the command is issued until the power failure occurs is ΔT. As shown in FIG.

  When a power failure / recovery occurs (step S11), the control unit 50 detects a time ΔT from when the command is transmitted from the command unit to when the power failure occurs when a power failure occurs (step S12). Then, the control unit 50 compares the time T1 until ΔT matches the command amount and the control amount (step S13). When ΔT is equal to or greater than T1 (step S13; No), the control unit 50 leaves the throttle opening of the throttle mechanism as it is (step S14). On the other hand, when ΔT is shorter than T1 (step S13; Yes), the control unit 50 calculates the difference between ΔT and T1, and calculates the difference amount between the command amount and the control amount stored in the storage device 52a. The command amount of the aperture mechanism is corrected by adding to the command amount (step S15).

  Thus, since the control amount of the throttle mechanism is corrected, the time required for correcting the control amount can be maintained in a short time, and an optimum refrigeration cycle can be maintained. In order to correct the command amount of the diaphragm mechanism in step S15, not only the control amounts of both the first diaphragm mechanism 5 and the second diaphragm mechanism 8 are modified, but also the first diaphragm mechanism 5 or the second diaphragm mechanism 8 is corrected. It is assumed that correction of one control amount is included.

Embodiment 3 FIG.
FIG. 7 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus 300 according to Embodiment 3 of the present invention. Based on FIG. 7, the refrigerant circuit structure and operation | movement of the air conditioning apparatus 300 are demonstrated. The air conditioner 300 performs a cooling operation or a heating operation using a refrigeration cycle in which a refrigerant is circulated. In the third embodiment, differences from the first and second embodiments will be mainly described, and the same parts as those in the first and second embodiments are denoted by the same reference numerals.

  The air conditioner 300 is different from the air conditioner 100 according to the first embodiment and the air conditioner 200 according to the second embodiment in the installation of various sensors and the initialization process of the throttle mechanism. Further, the function of the storage device (hereinafter referred to as the storage device 52b) is different from the air conditioner 100 according to the first embodiment and the air conditioner 200 according to the second embodiment. The storage device 52b stores the control amount and superheat degree SH1 of the first throttle mechanism 5 and the control amount and superheat degree SH2 of the second throttle mechanism 8 immediately before the power failure when a power failure occurs. The control amount and the degree of superheat to be stored may be data such as those used in advance during a test study instead of immediately before a power failure. The storage device 52b may be composed of a nonvolatile memory such as a flash memory. The storage device 52b may be built in the control unit 50.

  On the discharge side of the compressor 1, a high pressure sensor 61 that detects the pressure (high pressure) of the refrigerant discharged from the compressor 1 is provided. A low pressure sensor 62 that detects the pressure (low pressure) of the refrigerant sucked into the compressor 1 is provided on the suction side of the compressor 1. A first temperature sensor 65 that detects the temperature of the refrigerant is provided on the outlet side of the usage-side heat exchanger 6 (the outlet side in the refrigerant flow during the cooling operation). A second temperature sensor 66 that detects the temperature of the refrigerant is provided in a path that joins the path between the accumulator 7 and the four-way valve 2 from the outlet of the supercooling heat exchanger 4 on the bypass circuit.

  Information detected by various sensors (the high pressure sensor 61, the low pressure sensor 62, the first temperature sensor 65, and the second temperature sensor 66) is sent to the control unit 50. And the control part 50 controls the 1st aperture mechanism 5 and the 2nd aperture mechanism 8 to the target aperture opening based on the information from various sensors. Note that the refrigerant flow in the cooling mode of the air-conditioning apparatus 300 and the relationship between the opening of the throttle mechanism and the change in the refrigeration cycle are the same as those of the air-conditioning apparatus 100 according to Embodiment 1.

The calculation of the superheat degree (superheat degree SH1 and superheat degree SH2) of the refrigerant | coolant on the refrigerating cycle of the air conditioning apparatus 300 is demonstrated.
Using the pressure value detected by the low-pressure sensor 62, the saturation temperature is calculated from the pressure-saturation temperature relational expression determined for each refrigerant. Then, the degree of superheat can be calculated by subtracting the saturation temperature from the temperatures detected by the first temperature sensor 65 and the second temperature sensor 66. The calculation formula is as follows.

  FIG. 8 is a graph showing the relationship between the control amount of the throttle mechanism and the degree of superheat. Based on FIG. 8, the relationship between the control amount of the throttle mechanism and the degree of superheat will be described. FIG. 2 (a) shows the relationship between the control amount of the first throttle mechanism 5 and the superheat degree SH1, and FIG. 2 (b) shows the relationship between the control amount of the second throttle mechanism 8 and the superheat degree SH2. . In FIG. 2, the horizontal axis represents the control amount of the throttle mechanism, and the vertical axis represents the degree of superheat.

  As shown in FIG. 8, it can be seen that there is a one-to-one relationship between the control amount of the throttle mechanism and the degree of superheat. That is, if one control amount of the throttle mechanism is determined from FIGS. 2A and 2B, one degree of superheat corresponding to this one control amount is determined. Therefore, if the control amount of the throttle mechanism is known, the degree of superheat can be predicted. In other words, if the degree of superheat is known, the control amount of the throttle mechanism can be predicted.

  FIG. 9 is a flowchart showing the flow of processing for correcting the command amount of the aperture mechanism (the first aperture device 5 and the second aperture device 8) when a power failure occurs. Based on FIG. 9, correction of the command amount of the throttle mechanism when a power failure occurs, which is a feature of the air-conditioning apparatus 300 according to Embodiment 3, will be described.

  When a power failure / recovery occurs (step S21), the control unit 50 stores the control amount and superheat degree of the power failure straight line throttle mechanism in the storage device 52b (step S22). Then, the control unit 50 commands the control amount of the throttle mechanism immediately before the power failure stored in advance in the storage device 52b as the command amount. And the control part 50 compares and collates the present superheat degree and the superheat degree just before a power failure (step S24). When the current superheat degree and the superheat degree immediately before the power failure are the same (step S24; No), the control unit 50 leaves the throttle opening of the throttle mechanism as it is (step S25). On the other hand, when the current superheat degree and the superheat degree immediately before the power failure are not the same (step S24; Yes), the control unit 50 calculates a corresponding control amount difference from the difference between the superheat degrees, and the correction amount. (Step S26).

  In step S26, the calculated correction amount is added to the current command amount and commanded to obtain the control amount of the aperture mechanism. Thus, since the control amount of the throttle mechanism is corrected, the time required for correcting the command amount can be maintained in a short time, and an optimum refrigeration cycle can be maintained. In order to correct the command amount of the aperture mechanism in step S26, not only the control amounts of both the first aperture mechanism 5 and the second aperture mechanism 8 are corrected, but also the first aperture mechanism 5 or the second aperture mechanism 8 is corrected. It is assumed that correction of one control amount is included.

  A command amount is commanded to the throttle mechanism when the degree of superheat stored in advance in step S23 is set. In step S24, the command amount in step S23 and the control amount of the throttle mechanism stored in advance are stored. The same applies to the control flow in which the difference between the command amount and the control amount is the correction amount. Moreover, it is good also as control which combined the characteristic matter of each embodiment.

  As described above, in the air conditioning apparatus 300, the compressor 1, the heat source side heat exchanger 5, the high pressure side of the supercooling heat exchanger 4, the first throttle mechanism 5, and the use side heat exchanger 6 are connected in series. Branching between the main refrigerant circuit, the supercooling heat exchanger 4 and the first throttle mechanism 5, and the suction side of the compressor 1 through the second throttle mechanism 8 and the low pressure side of the supercooling heat exchanger 4 And the degree of superheat at the outlet of the use side heat exchanger 6 before and after the power failure and the degree of superheat at the outlet on the bypass path side of the supercooling heat exchanger 4 before and after the power failure. A control unit 50 is provided for correcting the opening command amount for the first throttle mechanism 5 and the second throttle mechanism 8 after power recovery by comparing each of them.

  And when the superheat degree before and after a power failure is not the same, the control part 50 calculates the difference of the corresponding control amount from the difference of the compared superheat degree, and corrects the opening degree with respect to the 1st aperture mechanism 5 and the 2nd aperture mechanism 8. The amount is supposed to be.

Claims (4)

A main refrigerant circuit in which a compressor, a heat source side heat exchanger, a high pressure side of a supercooling heat exchanger, a first throttle mechanism, and a use side heat exchanger are connected in series;
A bypass circuit branched between the supercooling heat exchanger and the first throttle mechanism, and connected to the suction side of the compressor via the second throttle mechanism and the low pressure side of the supercooling heat exchanger; An air conditioner having
When a power failure occurs in the air conditioner and an opening degree command is given to the first throttle mechanism and the second throttle mechanism, a time ΔT from when the power failure occurs to the first throttle mechanism and the second throttle mechanism. Comparing the required time T1 until the command amount of the opening degree with respect to the throttle mechanism and the control amount of the actual opening coincide with each other, the command of the opening degree with respect to the first throttle mechanism and the second throttle mechanism after power recovery With a control unit to correct the quantity,
The controller is
The allowable range of the actual opening control amount for the first throttle mechanism and the second throttle mechanism, and the command amount of the opening degree for the first throttle mechanism and the second throttle mechanism generated by one power failure, From the difference from the actual control amount of the opening, the number of power failures that can be permitted without initializing the first throttle mechanism and the second throttle mechanism is stored in advance as a specified number of times,
If a power failure count is less than said predetermined number of times which is stored in advance, while the initializing of the first throttle mechanism and the second throttle mechanism,
If a power failure count is the prescribed number of times or more which is stored in advance, said other of the first throttle mechanism and the second throttle mechanism is initialized, the first throttle mechanism and the second throttle mechanism The air conditioning apparatus characterized by correcting the command amount of the opening with respect to . When ΔT is equal to or greater than T1, the command amount of the opening degree for the first throttle mechanism and the second throttle mechanism is not corrected,
When ΔT is shorter than T1, an amount of difference between the command amount and the actual control amount of the opening is added to the opening command amounts stored in advance for the first and second throttle mechanisms. The air conditioning apparatus according to claim 1 , wherein the command amount of the opening degree for at least one of the first throttle mechanism and the second throttle mechanism is corrected. The number of power outages, the reference variable and the actual control amount of the opening with respect to the first throttle mechanism and the second throttle mechanism, or, according to claim 1 or 2, characterized in that a storage device for storing the degree of superheat The air conditioning apparatus described in 1. The air conditioner according to any one of claims 1 to 3 , further comprising a power source detection unit capable of detecting power supply and detecting power failure / recovery.

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