JP5109971B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner, and more particularly to a technique for adjusting a high pressure value of a refrigerant in an air conditioner according to a pipe length of a connecting pipe connecting a heat source side unit and a use side unit.

  Conventionally, when an air conditioner is installed, the connecting pipe connecting the indoor unit and the outdoor unit is set to a length (local pipe length) according to the situation of the site where the air conditioner is installed. At this time, since the pressure loss differs according to the set on-site pipe length, a technique for correcting the control target value of the capacity control by an amount corresponding to the pressure loss according to the on-site pipe length has been proposed (Patent Document 1).

A use-side unit including a compression mechanism, a use-side heat exchanger, an expansion mechanism, and a high-pressure side pressure sensor that detects a pressure of a refrigerant on a high-pressure side of the compression mechanism; a water-cooling heat source-side heat exchanger; and the heat source There has been proposed an air conditioner in which a heat source side unit including a refrigerant amount adjusting mechanism that adjusts a refrigerant amount flowing through a side heat exchanger is connected by a communication pipe.
Japanese Patent Laid-Open No. 5-288413

  According to the technique described in Patent Document 1, the reliability and control performance of the air conditioner are improved by appropriately changing the control target value of the compressor according to the pressure loss that varies depending on the pipe length. However, it is further desired to be able to operate efficiently according to the performance of the air conditioner and the local piping length.

  In addition, the water-cooled air conditioner is often not provided with a supercooler. In this case, if the local piping length is long, the pressure loss increases. For this reason, when the refrigerant flowing in the connecting pipe is a liquid refrigerant, the liquid refrigerant may be flushed in the middle of the connecting pipe. That is, the refrigerant pressure gradually decreases while flowing in the communication pipe. For this reason, when the refrigerant pressure falls below the saturation pressure corresponding to the refrigerant temperature at that time, a part of the liquid refrigerant evaporates in the pipe. When the liquid refrigerant is flushed in this manner, the refrigerant flow rate in the communication pipe is increased, and the flow resistance of the refrigerant becomes excessive. At this time, the electronic expansion valve of the use side unit attempts to secure the necessary refrigerant circulation amount by increasing the opening, but if the electronic expansion valve is fully opened, the electronic expansion valve cannot be controlled. This situation can be reduced by increasing the refrigerant pressure on the high-pressure side of the compressor, but efficient operation cannot be performed simply by maintaining the refrigerant pressure at a high value.

  The present invention was made to solve the above problems, and according to the performance of the air conditioner and the local piping length of the connecting piping connecting the heat source side unit and the usage side unit, the high pressure value of the refrigerant is It aims at setting to the value which can perform an efficient driving | operation, avoiding that an electronic expansion valve will be in an uncontrollable state.

The invention according to claim 1 of the present invention includes a use side unit (2) including a use side heat exchanger (23) and an expansion mechanism (24), a heat source side heat exchanger (32), and a refrigerant amount adjusting mechanism ( 31), the refrigerant amount adjustment mechanism (31) is an electric valve (311) and an electromagnetic valve (312) that change the amount of refrigerant passing through the heat source side heat exchanger (32), and the heat source side heat exchange. A bypass valve (313) that varies the amount of refrigerant that bypasses the vessel (32), and the opening degree of the motor-operated valve (311), electromagnetic valve (312), and bypass valve (313) is variable. the heat source-side heat exchanger heat source side unit you adjust the amount of coolant flowing through the (32) (3) and are connected by communication pipes (6, 7), the compression mechanism (21, 22) and the compression mechanism (21 , 22) is a high-pressure side pressure sensor (202) for detecting the pressure of the refrigerant on the high-pressure side is an air conditioner (1) provided in either the use side unit (2) or the heat source side unit (3). And
A pipe length input section (208) into which the local pipe length of the communication pipe (6, 7) is input by an operator;
A target for calculating a target high pressure value according to the drive frequency of the compression mechanism (21, 22) held in advance and the value of the local pipe length input to the pipe length input unit (208) by an operator. High pressure value calculation unit (2051),
Based on the difference between the target high pressure value calculated by the target high pressure value calculation unit (2051) and the high pressure value detected by the high pressure side pressure sensor (202), the bypass valve of the refrigerant quantity adjusting mechanism (31) An opening calculation unit (2052) for calculating the opening of (313) ;
A mode storage unit (2053) for storing a plurality of modes consisting of combinations of respective opening degrees of the electric valve (311), the electromagnetic valve (312) and the bypass valve (313);
A selection unit that selects a mode corresponding to the detected high pressure value from a plurality of modes stored in the mode storage unit (2053) based on the high pressure value detected by the high pressure side pressure sensor (202). (2054) and
The motor-operated valve (311), the solenoid valve according to the respective opening degrees of the motor-operated valve (311), the solenoid valve (312) and the bypass valve (313) indicated by the mode selected by the selector (2054) (312) and a control unit (301) for controlling the respective opening degrees of the bypass valve (313) ,
The control unit (301) performs control to change the mode when the high pressure value detected by the high pressure side pressure sensor (202) is not within a predetermined range, while the high pressure value is within the predetermined range. When it is, without changing the mode, to control the opening of the bypass valve (313) using the opening calculated by the opening calculation unit (2052),
It is characterized by this .

In this invention, the target high pressure value calculation unit calculates the target high pressure value according to the driving frequency of the compression mechanism and the value of the local pipe length input to the pipe length input unit by the operator, and the opening degree calculation unit And calculating the opening degree of the bypass valve of the refrigerant quantity adjusting mechanism based on the difference between the calculated target high pressure value and the high pressure value detected by the high pressure side pressure sensor, and the controller opens the calculated opening. Since the bypass valve of the refrigerant quantity adjusting mechanism is controlled to open and close at a high degree, the high pressure value of the refrigerant is actually distributed to the site while avoiding that the expansion mechanism (for example, the electronic expansion valve) of the use side unit becomes uncontrollable. It is a value corresponding to the installed local pipe length, and can be a value corresponding to the performance of the air conditioner caused by the drive frequency of the compression mechanism. For this reason, it becomes possible to operate the air conditioner efficiently corresponding to the local pipe length while ensuring the performance of the air conditioner. For example, even if the local piping length is long and the pressure loss is large for a water-cooled air conditioner that does not have a supercooler, according to the present invention, the electronic expansion valve of the usage-side unit can be It is possible to avoid being out of control and to set the value so that the air conditioner can be operated efficiently.
In the present invention, the selection unit selects a mode corresponding to the high pressure value detected by the high pressure side pressure sensor from the plurality of modes stored in the mode storage unit, and the opening indicated by the selected mode. Therefore, the control unit controls the opening degree of the motor-operated valve, the solenoid valve, and the bypass valve, so that the motor-operated valve, the solenoid valve, and the bypass valve exhibit a certain performance by the air conditioner according to the current high pressure value. The opening can be adjusted to an opening that provides a high pressure value that allows efficient operation.
In particular, when the high pressure value detected by the high pressure side pressure sensor is not within a predetermined range, the control unit performs control to change the mode, so that the electronic expansion valve of the use side unit is flushed with the liquid refrigerant. Can be prevented from going out of control, and the air conditioner can be set to a value that can be operated efficiently.
On the other hand, when the high-pressure value is within a predetermined range, the control unit does not change the mode, and uses the opening calculated by the opening calculation unit (2052) of the bypass valve (313). By controlling the opening, it becomes possible to control the opening of the bypass valve in accordance with the fluctuation of the high pressure value without changing the mode. Accordingly, it is possible to adjust the opening degree so that a certain performance of the air conditioner is exhibited, and the opening degree can obtain a high pressure value capable of performing an efficient operation.

The invention according to claim 2 is the air conditioner according to claim 1 , wherein the target high pressure value calculation unit (2051) has already set the mode selected by the selection unit (2054). The target high pressure value is calculated when the same as the previous mode being performed, and the opening degree calculation unit (2052) calculates the opening degree of the bypass valve (313) using the calculated target high pressure value. The control unit (301) controls the opening and closing of the bypass valve (313) using the calculated opening degree.

  According to this invention, when the mode selected by the selection unit is the same as the previous mode that has already been set, the target high pressure value calculation unit calculates the target high pressure value, and the calculated target high pressure value Is used to calculate the opening of the bypass valve, and the control unit controls the opening and closing of the bypass valve using the calculated opening, so that the air conditioner is constant according to the current high pressure value. It is possible to adjust the bypass valve to an opening at which a high pressure value capable of performing an efficient operation is obtained while maintaining the state of the electric valve, the electromagnetic valve, and the bypass valve at the opening at which the above performance is exhibited.

The invention according to claim 3 is the air conditioner according to claim 2 , wherein the mode selected by the selection unit (2054) is the same as the previous mode that has already been set, The opening degree calculation unit (2052) calculates the opening degree of the refrigerant amount adjustment mechanism (31), and the control unit (301) uses the calculated opening degree to change the refrigerant amount adjustment mechanism (31). In the case of opening / closing control, when the opening degree of the bypass valve (313) reaches the upper limit or the lower limit, the selection unit (2054) determines that the opening degree of the bypass valve (313) is in the range from the lower limit value to the upper limit value. Another mode is newly selected, and the control unit (301) sets the motor-operated valve (311), the electromagnetic valve (312), and the bypass valve (313) indicated by the newly selected mode. According to each opening, the opening of each of the motor-operated valve (311), the solenoid valve (312) and the bypass valve (313) is controlled. is there.

  In this invention, when the opening degree of the bypass valve reaches the lower limit value or the upper limit value in the mode by the opening degree control of the bypass valve in the mode, the bypass valve opening degree in the mode for improving the operation efficiency. By changing not only the adjustment but also the opening of the refrigerant quantity adjusting mechanism itself by changing the mode, a state where a certain performance is exhibited by the air conditioner is ensured.

The invention described in Claim 4 is the air conditioner according to any one of claims 1 to 3, wherein the target pressure value calculated by the target high pressure value calculating section (2051) pressure When the absolute value of the difference from the high pressure value detected by the side pressure sensor (202) is larger than a predetermined value, the opening degree of the bypass valve (313) is increased by a predetermined amount. It is something to be made.

Further, an invention according to claim 5, an air conditioner according to any one of claims 1 to 4, wherein the control unit (301), the mode selected by the selection unit (2054) Is changed from the previous mode that has already been set, the opening of the bypass valve (313) until then, the opening of the bypass valve (313) indicated by the new mode after the change When the opening of the bypass valve (313) is changed to the opening of the upper limit or lower limit indicated by the new mode after the change. Thus, the refrigerant amount adjusting mechanism (31) including the bypass valve (313) is controlled to open and close.

  According to these inventions, when the fluctuation of the high pressure value is large, the amount of change of the bypass valve opening is increased accordingly, so the opening degree of the refrigerant amount adjusting mechanism is more accurately set to the current high pressure value. Accordingly, it is possible to adjust the opening so that a certain performance of the air conditioner is exhibited and a high pressure value capable of performing an efficient operation can be obtained.

According to a sixth aspect of the present invention, in the air conditioner according to any of the second to fifth aspects, the expansion mechanism (24) of the use side unit (2) is configured. It further includes an expansion mechanism control unit (2055) for controlling the opening of the valve,
The target high pressure value calculation unit (2051) is configured such that the opening degree of the valve constituting the expansion mechanism (24) obtained from the expansion mechanism control unit (2055) ensures the normal operation of the expansion mechanism (24). If it is determined that the state of the upper limit value continues for a predetermined time, the target high pressure value is calculated by increasing the predetermined high pressure value, and the calculated target high pressure value The opening calculation unit (2052) calculates the opening of the refrigerant amount adjustment mechanism (31) using the control unit (301), the control unit (301) using the calculated opening, the refrigerant amount adjustment mechanism ( 31) is controlled to open and close.

  If the opening of a valve (for example, an electronic expansion valve) that constitutes the expansion mechanism of the usage-side unit remains at the upper limit value for ensuring the normal operation of the expansion mechanism, it continues at that time. In such a case, the present invention further increases the target high pressure value by a certain value and restarts the adjustment by changing the opening of the refrigerant amount adjusting mechanism corresponding to the high pressure value. By setting, it is ensured that the electronic expansion valve of the usage-side unit is uncontrollable due to the flashing of the liquid refrigerant, and the operation efficiency is improved.

  According to the present invention, according to the performance of the air conditioner and the local piping length of the connecting piping connecting the heat source side unit and the usage side unit, the high pressure value of the refrigerant is controlled to be in an uncontrollable state. It is possible to set to a value that allows efficient operation while avoiding.

  Hereinafter, an air conditioner according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an air conditioner according to an embodiment of the present invention.

  The air conditioner 1 according to the present embodiment is a device used for cooling an IT device, for example. The air conditioner 1 includes a use side unit 2 and a heat source side unit 3. The use side unit 2 and the heat source side unit 3 are connected by connecting pipes 6 and 7. That is, the refrigerant circuit 10 of the air conditioner 1 is configured by connecting the use side unit 2 and the heat source side unit 3 via the connection pipes 6 and 7. In the refrigerant circuit 10, for example, chlorofluorocarbon R410A is sealed as a refrigerant. In the air conditioner 1, the cooling operation is performed by compressing the CFC gas R410A as the refrigerant until the pressure becomes equal to or higher than the critical pressure.

  The user side unit 2 will be described. The usage-side unit 2 has a usage-side refrigerant circuit 101 that constitutes a part of the refrigerant circuit 10. The use-side refrigerant circuit 101 includes a plurality (two in this embodiment) of compressors (compression mechanisms) 21 and 22, a use-side heat exchanger 23, an expansion mechanism 24 as an expansion mechanism that depressurizes the refrigerant, and a closure And valves 25 and 26.

  The use side heat exchanger 23 functions as an evaporator for cooling the object to be cooled (IT apparatus in the present embodiment). The use side heat exchanger 23 has one end connected to the expansion mechanism 24 and the other end connected to the suction side of the compressors 21 and 22.

  One end of the expansion mechanism 24 is divided by the flow divider 28 and connected to the use-side heat exchanger 23, and the other end is connected to the closing valve 25. The expansion mechanism 24 includes an electronic expansion valve 241, an electromagnetic valve 242, and a bypass valve 243.

  The electronic expansion valve 241 expands the refrigerant by changing the opening, and changes the amount of the refrigerant passing through the refrigerant circuit and reaching the use-side heat exchanger 23 and the compressors 21 and 22. In the present embodiment, two electronic expansion valves 241 are provided in the use side refrigerant circuit 101, and the two electronic expansion valves 241 are connected in parallel to each other.

  The electromagnetic valve 242 is a valve that controls whether or not the refrigerant passes through the electronic expansion valve 241 by switching between an open state and a closed state. The bypass valve 243 is provided in the bypass circuit 101 a that bypasses the electronic expansion valve 241 and the electromagnetic valve 242, and bypasses the electronic expansion valve 241 and the electromagnetic valve 242 to reach the use side heat exchanger 23 and the compressors 21 and 22. The amount of the refrigerant is adjusted.

In the present embodiment, the usage-side unit 2 includes a fan 270 for sucking outside air into the unit, exchanging heat, and then discharging it outside the unit. Heat exchange with flowing refrigerant. The fan 270 is rotationally driven by a fan motor 271 .

  The shut-off valves 25 and 26 are valves provided at connection ports with external devices and pipes (specifically, connection pipes 6 and 7). The closing valve 25 is connected to the expansion mechanism 24. The closing valve 26 is connected to the discharge side of the compressors 21 and 22.

  The compressors 21 and 22 compress the low-pressure gas refrigerant until the pressure becomes equal to or higher than the critical pressure. The compressors 21 and 22 are connected to each other in parallel in the refrigerant circuit. The compressor 21 is an inverter control type compressor that is driven so that the capacity can be adjusted by changing the drive frequency in accordance with the required air conditioning capacity (the capacity variable control will be described later). The compressor 22 is a compressor that is driven at a constant speed with a constant capacity. The refrigerant that has passed through the use-side heat exchanger 23 is divided and supplied to the compressors 21 and 22.

  A pressure switch 27 and an oil separator 29 are provided on the discharge side of each of the compressors 21 and 22. A circuit is connected so that a part of the refrigerant that has passed through the oil separator 29 is returned to the other compressor. Further, the use side refrigerant circuit 101 is connected so that the refrigerant after passing through the oil separator 29 is joined and reaches the closing valve 26.

  Furthermore, a low-pressure sensor 201 that detects a refrigerant pressure in a low-pressure state before compression by the compressors 21 and 22 is provided on the suction side of the compressors 21 and 22 and before the diversion by the flow divider 28. A high pressure sensor (high pressure side pressure sensor) 202 for detecting a refrigerant pressure in a high pressure state after being compressed by the compressors 21 and 22 is provided in a circuit portion on the discharge side of the compressors 21 and 22 after the refrigerant is merged. Is provided.

  It should be noted that a filter 203 and a check valve 204 are disposed at the main points of the usage side refrigerant circuit 101 of the usage side unit 2.

  Next, the heat source side unit 3 will be described. The heat source side unit 3 includes a heat source side refrigerant circuit 102 that constitutes a part of the refrigerant circuit 10. The heat source side refrigerant circuit 102 includes a refrigerant amount adjusting mechanism 31 that depressurizes the refrigerant and a heat source side heat exchanger 32.

  The refrigerant amount adjusting mechanism 31 includes an electric valve 311, an electromagnetic valve 312, and a bypass valve 313. The electric valve 311 and the electromagnetic valve 312 are provided in the heat source side refrigerant circuit 102 in parallel with each other, and are connected to the heat source side heat exchanger 32. The electric valve 311 adjusts the flow rate of the refrigerant flowing through the heat source side refrigerant circuit 102 via the heat source side heat exchanger 32 by adjusting the opening / closing amount of the valve. The electromagnetic valve 312 is configured to adjust the flow rate of the refrigerant flowing through the heat source side refrigerant circuit 102 via the heat source side heat exchanger 32 by switching between an open state and a closed state. The bypass valve 313 is provided in the bypass circuit 102 a that bypasses the heat source side heat exchanger 32, and adjusts the amount of refrigerant that bypasses the heat source side heat exchanger 32.

  The heat source side heat exchanger 32 is a water-cooled heat exchanger in the present embodiment. One end of the heat source side heat exchanger 32 is connected to the use side unit 2 via the connection pipe 7, and the other end is connected to the motor-operated valve 311 and the electromagnetic valve 312. Cooling water pipes 321 and 322 are connected to the heat source side heat exchanger 32. The heat source side heat exchanger 32 passes the cooling water supplied from the cooling water pipe 321 into the heat exchanger, cools the refrigerant in the heat exchanger with the cooling water, and the cooling water that has finished cooling the refrigerant is It is discharged from the cooling water pipe 322 to the outside of the heat source side heat exchanger 32.

  Further, the heat source side unit 3 is provided with closing valves 34 and 35. The closing valves 34 and 35 are valves that close the end of the heat source side refrigerant circuit 102. The closing valves 34 and 35 are opened when the heat source side unit 3 is installed on site, and the connecting pipes 6 and 7 are connected to the closing valves 34 and 35. The connection pipes 6 and 7 connect the shut-off valves 34 and 35 of the heat source side unit 3 and the shut-off valves 25 and 26 of the use-side unit 2 so that the use-side unit 2 side having the compressors 21 and 22 is connected. The use side refrigerant circuit 101 and the heat source side refrigerant circuit 102 are connected to form the refrigerant circuit 10.

  When the air conditioner 1 is installed at the installation location, the connecting pipes 6 and 7 are arranged with their length adjusted in accordance with the distance between the use side unit 2 and the heat source side unit 3 at the site. Refrigerant piping.

  In addition, the heat source side refrigerant circuit 102 is provided with a refrigerant regulator 36 that adjusts the amount of refrigerant circulating in the refrigerant circuit 10, a check valve 37, a pressure adjustment valve 38, and a filter 39 at appropriate positions. The pressure regulating valve 38 is a valve that varies the pressure of the refrigerant flowing through the refrigerant circuit 10 (heat source side refrigerant circuit 102).

  A schematic configuration of a control system and main mechanisms of the air conditioner 1 will be described. FIG. 2 is a block diagram showing a schematic configuration of a control system and main mechanisms of the air conditioner 1. FIG. 3 is a diagram showing a plurality of stages composed of combinations of driving frequencies and driving states for driving the compressor.

  The use side unit 2 includes a use side control unit 205, a drive control circuit 206, an inverter control circuit 207, a pipe length input unit 208, the high pressure sensor 202, the low pressure sensor 201, the fan motor 271, and the expansion mechanism 24 described above. And.

  The use side control unit 205 includes a microcomputer, a memory, and the like, and performs operation control of each unit constituting the use side unit 2. For example, the use side control unit 205 transmits and receives control signals and the like to and from the heat source side control unit 301 of the heat source side unit 3 via the transmission line 8.

  The drive control circuit 206 performs drive control of the compressor 22 driven at a constant speed (a predetermined drive frequency Hz). The inverter control circuit 207 is a control circuit that drives and controls the compressor 21 of the inverter control system, and drives the compressor 21 by changing its operating capacity by appropriately changing the driving frequency (Hz) of the compressor 21. .

  Here, in order to vary the capacity of the compressors 21 and 22 in accordance with the required air conditioning capacity, the use side control unit 205 has a plurality of stages as shown in FIG. 3, for example (in this embodiment, when commercial power is 50 Hz) 23Steps (stages) are stored in advance, and the drive frequency of the compressor 21 and the drive ON / OFF switching values of the compressor 22 are stored. The inverter control circuit 207 changes the drive frequency of the compressor 21 according to the value indicated by one step selected from the plurality of stages by the use side control unit 205 according to the required air conditioning capacity. The control for changing the capacity is performed, and the drive control circuit 206 performs control for switching whether the compressor 22 is driven or stopped.

The high pressure sensor 202 detects the refrigerant pressure after being compressed by the compressors 21 and 22, and outputs the detected high pressure value (the value of the refrigerant pressure after being compressed by the compressors 21 and 22) to the use side control unit 205 .

The low-pressure sensor 201 is a sensor that detects the refrigerant pressure before being compressed by the compressors 21 and 22, and outputs the detected low-pressure value (the value of the refrigerant pressure before being compressed by the compressors 21 and 22) to the usage-side control unit 205 . To do.

  As described above, the expansion mechanism 24 includes the electronic expansion valve 241, the electromagnetic valve 242, and the bypass valve 243, and the opening / closing or opening degree of each valve is controlled by the use-side control unit 205.

  The operation of the fan motor 271 that is a drive source of the fan 270 (FIG. 1) that sends air to the usage-side heat exchanger 23 is controlled by the usage-side control unit 205.

  The pipe length input unit 208 is used to input the local pipe lengths of the communication pipes 6 and 7 by an operator (such as an operator who performs installation or maintenance work of the air conditioner 1). For example, the pipe length input unit 208 includes a part of an operation panel or the like provided on the side surface portion on the front side of the outer casing that covers the usage-side unit 2, and includes operation buttons and numeric keys provided as the operation panel. The value of the local piping length is input by the operation by the operator.

  Since the connecting pipes 6 and 7 have different installation positions of the use side unit 2 and the heat source side unit 3 depending on the installation place and installation environment of the air conditioner 1, the actual use of the use side unit 2 and the heat source side unit 3 is different. Depending on the installation position, the length of the connecting pipe that connects the use side unit 2 and the heat source side unit 3 varies. For this reason, the lengths of the communication pipes 6 and 7 that are necessary at the time of actual installation are input as the local pipe length. In the present embodiment, the on-site piping length is the length of the connecting piping 6 and 7 from the closing valves 25 and 26 of the use side unit 2 to the closing valves 34 and 35 of the heat source side unit 3. Here, it is assumed that the same one value is input as the local pipe length of both the communication pipe 6 and the communication pipe 7.

  In addition, the heat source side unit 3 includes a heat source side control unit 301 that controls the operation of each unit constituting the heat source side unit 3 and the refrigerant amount adjusting mechanism 31 described above. The heat source side control unit (control unit) 301 includes a microcomputer, a memory, and the like provided to control the heat source side unit 3, and is controlled with the usage side control unit 205 of the usage side unit 2. Transmit and receive signals. The heat source side control unit 301 is configured to adjust the refrigerant amount based on the opening degree information and the selected mode information sent from the usage side control unit 205 (the opening degree calculation unit 2052 and the selection unit 2054) of the usage side unit 2. The opening degree of the motor-operated valve 311, the electromagnetic valve 312, and the bypass valve 313 that constitute the engine 31 is controlled.

  As described above, the air conditioner 1 controls each device of the use side unit 2 and the heat source side unit 3 by the use side control unit 205 and the heat source side control unit 301 connected by the transmission line 8. A cooling operation is performed, the usage-side heat exchanger 23 is caused to function as an evaporator, and the IT device that is the object to be cooled is cooled. Here, the use side control unit 205 and the heat source side control unit 301 connected by the transmission line 8 function as the overall control unit 500 of the air conditioner 1.

  Next, the configuration of the use side control unit 205 will be further described. FIG. 4 is a block diagram showing a configuration of the use side control unit 205. FIG. 5 is a diagram showing each mode indicating the opening degree of each valve provided as the refrigerant amount adjusting mechanism 31.

  The use side control unit 205 includes a target high pressure value calculation unit 2051, an opening degree calculation unit 2052, a mode storage unit 2053, a selection unit 2054, and each mechanism control unit 2055.

  The target high pressure value calculation unit 2051 determines the drive frequency of the compressor 21 and the compressor 22 indicated by one step selected from the above-described plurality of steps (FIG. 3) by the use side control unit 205 according to the required air conditioning capacity. A target high pressure value corresponding to the drive state and the value of the local pipe length input to the pipe length input unit 208 by the operator is calculated. Note that the target high pressure value calculation unit 2051 obtains the drive frequencies of the compressors 21 and 22 from the drive control circuit 206 and the inverter control circuit 207 or the use side control unit 205 and stores them.

When the operator inputs the value of the local piping length m to the piping length input unit 208, the target high pressure value calculation unit 2051 calculates the high pressure value P that matches the local piping length m. For example, the target high pressure value calculation unit 2051 calculates the high pressure value P commensurate with the local piping length by substituting the local piping length m into the following formula (1).
P = 0.138462 * m ＋ 15.307692… (1)
Subsequently, the target high pressure value calculation unit 2051 uses the calculated high pressure value P to calculate a target high pressure value A that matches the driving frequency of the compressor 21 and the driving state of the compressor 22 based on the following equation (2). calculate.
A = f (Hz, m) = a * Compressor Step + b, a = (P-16) / 19, b = (320-P) / 19… (2)
However, in the case of the compressors Step 21 to 23, the calculation is performed as the compressor Step 20 in the equation (2).

  In addition, the said Formula (2) is set according to the step content and step number which the said several step about the compressors 21 and 22 shows.

For example, when the compressors 21 and 22 are driven at the driving frequency or driving state shown in Step 20 shown in FIG. 3 (compressor Step = 20) and the local piping length m = 25, the target The high pressure value calculation unit 2051
High pressure P = 0.138462 * 25 + 15.307692 = 18.769242
a = (P-16) / 19 = (18.769242-16) /19=0.145749578
b = (320-P) / 19 = (320-18.769242) /19=15.85425044
Target high pressure value A = f (Hz, m) = a * Compressor Step + b = 0.145749578 * 20 + 15.85425044 = 18.76kg is calculated.

  The opening degree calculation unit 2052 is based on the difference between the target high pressure value calculated by the target high pressure value calculation unit 2051 and the high pressure value detected by the high pressure sensor 202, and the opening degree (unit) of the bypass valve 313 of the refrigerant quantity adjustment mechanism 31. pls). The opening calculation unit 2052 uses the target high pressure value A calculated by the target high pressure value calculation unit 2051 to calculate the amount of change in the opening of the bypass valve 313 by the following equations (3) and (4), thereby bypassing The opening degree of the valve 313 is calculated.

If the current high pressure value-target high pressure value A> 0.5, or the current high pressure value-target high pressure value A <-0.5,
Bypass valve 313 opening change amount = −2 × (current high pressure value−high pressure value A)
However, opening change amount is rounded off, upper limit is +10, lower limit is -10… (3)
-0.5 ≦ current high pressure value−target high pressure value A ≦ 0.5 Bypass valve 313 opening change amount Bypass valve opening change amount = − (current high pressure value−target high pressure value A)
However, opening change amount is rounded off, upper limit is +10, lower limit is -10… (4)
The target high pressure value calculation unit 2051 and the opening degree calculation unit 2052 calculate the target high pressure value and the bypass valve opening degree when the mode is not changed by mode selection by the selection unit 2054 described later.

  The mode storage unit 2053 stores a plurality of modes including combinations of respective opening degrees of the motor operated valve 311, the electromagnetic valve 312, and the bypass valve 313 provided as the refrigerant amount adjusting mechanism 31. The plurality of modes include, for example, 19 levels of modes as shown in FIG. 5, and the mode storage unit 2053 stores the 19 levels of modes.

  The selection unit 2054 selects a mode corresponding to the detected high pressure value from a plurality of modes stored in the mode storage unit 2053 based on the high pressure value detected by the high pressure sensor 202. The selection unit 2054 changes the already set mode depending on whether the high pressure value detected by the high pressure sensor 202 is larger or smaller than a predetermined value (details will be described later).

  Each mechanism control unit (expansion mechanism control unit) 2055 is in charge of operation control of each unit constituting the use-side unit 2.

  Further, the opening degree calculation unit 2052 and the selection unit 2054 transmit the calculated opening degree information and the selected mode information to the heat source side control unit 301 of the heat source side unit 3.

  Next, operation | movement of the air conditioner 1 of this embodiment is demonstrated. When the air conditioner 1 is installed on site by the operator, the closing valves 25, 26, 34, and 35 are fully opened. When an operation start command is input by the operation of the operation panel by the operator, the usage-side control unit 205 (each mechanism control unit 2055) passes through the drive control circuit 206 and the inverter control circuit 207, and the compressors 21, 22, The fan motor 271 of the fan 270 is activated. As a result, the low-pressure gas refrigerant is sucked into the compressors 21 and 22 and is compressed until the pressure becomes equal to or higher than the critical pressure to become a high-pressure gas refrigerant.

Thereafter, the high-pressure gas refrigerant discharged from each of the compressors 21 and 22 is merged and then sent to the heat source side unit 3 via the connection pipe 7, and heat exchange is performed by the cooling water in the heat source side heat exchanger 32. Then it is cooled. At this time, the amount of the refrigerant that bypasses the heat source side heat exchanger 32 is appropriately adjusted by the bypass valve 313 of the refrigerant quantity adjusting mechanism 31. Further, the high-pressure liquid refrigerant cooled through the heat source side heat exchanger 32 is used via the connection pipe 6 after the flow rate is adjusted by the electric valve 311 and the electromagnetic valve 312 of the refrigerant amount adjusting mechanism 31. Sent to the side unit 2.

  After the flow rate of the high-pressure liquid refrigerant returned to the usage-side unit 2 is adjusted by the electromagnetic valve 242 and the bypass valve 243, the suction pressures of the compressors 21 and 22 (the pressure of the low-pressure gas refrigerant are adjusted by the two electronic expansion valves 241) ) The pressure is reduced to near and becomes a low-pressure gas-liquid two-phase refrigerant, and then the refrigerant is diverted by the diverter 28 and sent to the use side heat exchanger 23. The use-side heat exchanger 23 functions as an evaporator, and the use-side heat exchanger 23 absorbs heat by heat exchange with the surrounding air to cool the surrounding air, thereby the IT device that is the object to be cooled. Cool down. The low-pressure gas refrigerant that has passed through the use-side heat exchanger 23 is again sucked into the compressors 21 and 22 and circulates through the refrigerant circuit 10.

  Next, each valve opening / closing control of the refrigerant quantity adjusting mechanism 31 in the use side unit 2 of the air conditioner 1 will be described. FIG. 6 is a flowchart showing a flow of processing at the time of each valve opening / closing control of the refrigerant amount adjusting mechanism 31 in the usage-side unit 2 of the air conditioner 1. FIG. 7 is a graph showing the relationship between the compressor performance, the target high pressure value, and the local pipe length.

  By the operation of the operation panel of the use side unit 2 by the operator, the operation start instruction of the air conditioner 1 and the local pipe length value m are input (YES in S1), and the operation start instruction is received by the heat source side control unit 301. When received by each mechanism control unit 2055, the use side control unit 205, the drive control circuit 206, and the inverter control circuit 207 compress at the drive frequency and drive state indicated by the predetermined step for initial operation (FIG. 3). The selection unit 2054 selects a predetermined initial operation mode from the modes stored in the mode storage unit 2053 (in this embodiment, the mode shown in FIG. 5). 0 is selected as the mode for the initial operation), the control unit 2055 sets each of the electronic expansion valve 241, the electromagnetic valve 242, and the bypass valve 243 indicated by the selected mode. According opening, electronic expansion valve 241, and setting the respective opening of the solenoid valve 242 and the bypass valve 243. The input value of the local pipe length is stored in the target high pressure value calculation unit 2051.

Subsequently, under the control of the use side control unit 205, the high pressure sensor 202 and the low pressure sensor 201 detect the high pressure value and the low pressure value (unit: kg / cm ² ) of the refrigerant before and after the compressors 21 and 22 (S2). .

When the high pressure value and the low pressure value are detected, the selection unit 2054 selects a mode corresponding to the high pressure value and the low pressure value from the modes stored in the mode storage unit 2053 based on the high pressure value. To do. First, the selection unit 2054 determines whether or not the detected high pressure value is greater than a predetermined value P1 (S3). For example, the selection unit 2054 performs the determination with the predetermined value P1 as 32.0 kg / cm ² .

  When the detected high pressure value is greater than the predetermined value P1 (YES in S3), the selection unit 2054 determines the mode set at this time (the above-mentioned predetermined time when starting the air conditioner 1 is started). A mode that is one step higher than the previously set mode is selected during operation after the start of activation of the air conditioner 1 (S20). In the example shown in FIG. 5, the mode indicates that the level is higher as the mode number is smaller.

  The heat source side control unit 301 sets the degree of opening of each of the electric valve 311, the electromagnetic valve 312, and the bypass valve 313 at the opening indicated by the selected new mode (S 21). When the opening degree of the bypass valve 313 up to that time exceeds the upper limit value of the opening degree of the bypass valve 313 indicated by the new mode after the change, the heat source side control unit 301 opens the bypass valve 313. The degree of opening is changed to the opening degree of the new upper limit value indicated by the mode after the change, and the bypass valve 313 is controlled to open and close. Thereafter, the process proceeds to S12.

On the other hand, when the detected high pressure value is equal to or smaller than the predetermined value P1 (NO in S3), the selection unit 2054 determines whether or not the detected high pressure value is smaller than the predetermined value P2 (P1> P2). (S4). For example, the selection unit 2054 performs the determination with the predetermined value P1 as 15.0 kg / cm ² .

  When the detected high pressure value is smaller than the predetermined value P2 (YES in S4), the selection unit 2054 selects a mode one level lower than the mode set at this time (S22).

  The heat source side control unit 301 sets the degree of opening of each of the electric valve 311, the electromagnetic valve 312, and the bypass valve 313 at the opening indicated by the selected new mode (S <b> 23). When the opening degree of the bypass valve 313 up to that time is less than the lower limit value of the opening degree of the bypass valve 313 indicated by the new mode after the change, the heat source side control unit 301 opens the bypass valve 313. After the degree is changed to the opening of the new lower limit value indicated by the changed mode, the bypass valve 313 is controlled to open and close. Thereby, for example, when the necessary high pressure is not sufficient particularly in low outside air (only when the high pressure is low), the high-temperature high-pressure gas compressed by the compressors 20 and 21 is converted into the heat source side heat exchanger 32 by the bypass valve 313. The high pressure value is increased by bypassing.

  When the detected high pressure value is equal to or greater than the predetermined value P2 (NO in S4), the selection unit 2054 selects the ratio between the detected high pressure value and low pressure value, that is, the high pressure value / low pressure value (compressor 21, It is determined whether or not the compression ratio indicated by 22 (discharge pressure / suction pressure) is smaller than a predetermined value r (S5). For example, the selection unit 2054 makes the determination by setting the predetermined value r to 0.1.

  If the selection unit 2054 determines that the compression ratio is smaller than the predetermined value r (YES in S5), the process proceeds to S22 and S23.

  When the compression ratio is equal to or greater than the predetermined value r (NO in S5), the selection unit 2054 does not select a new mode and maintains the previously set mode. As described above, when the mode is not changed, the target high pressure value calculation unit 2051 calculates the high pressure value P commensurate with the input local pipe length m (S6). As described above, for example, the target high-pressure value calculation unit 2051 determines that the user side unit 2 and the heat source of the air conditioner 1 actually installed based on the input local pipe length m and the above-described equation (1). The high pressure value P commensurate with the local piping length m between the side unit 3 is calculated.

  Subsequently, the target high pressure value calculation unit 2051 uses the calculated high pressure value P to calculate a target high pressure value A corresponding to the driving frequency or driving state of the compressors 21 and 22 by the above-described equation (2) ( S7).

  Thereafter, the opening degree calculation unit 2052 calculates the amount of change of the opening degree of the bypass valve 313 by the above-described equations (3) and (4) using the calculated target high pressure value A, and opens the bypass valve 313. The degree is calculated (S8, S9, S16, S18).

  That is, when the current high pressure value−target high pressure value A> 0.5 or the current high pressure value−target high pressure value A <−0.5 (YES in S8), the opening degree calculation unit 2052 opens the opening degree of the bypass valve 313. The amount of change is -2 x (current high pressure value-target high pressure value A) (unit: pls) (S16; However, the amount of opening change is rounded off, the upper limit is +10, the lower limit is -10 ). The heat source side control unit 301 sets the state of the conventional bypass valve 313 to a state where the opening degree (unit: pls) is changed by the calculated change amount (S17).

  On the other hand, when -0.5 ≦ current high pressure value−high pressure value A ≦ 0.5 (NO in S8, YES in S9), the opening calculation unit 2052 sets the opening change amount of the bypass valve 313 as − (current high pressure value). -The value (unit: pls) calculated by the high pressure value A) (S18; where the amount of change in opening is rounded off, the upper limit is +10, and the lower limit is -10). The heat source side control unit 301 sets the state of the conventional bypass valve 313 to a state where the opening degree (unit: pls) is changed by the calculated change amount (S19).

  After S17, S19 or S9, when the calculated opening degree of the bypass valve 313 reaches the upper limit or lower limit set in the currently set mode (YES in S10), the selection unit 2054 changes the mode to a one-step upper or lower mode including the calculated bypass opening after the change from the lower limit to the upper limit, and the heat source side control unit 301 changes each opening indicated by the changed mode. Thus, the opening degree of each of the electric valve 311, the electromagnetic valve 312 and the bypass valve 313 is set (S11). That is, when the opening degree of the bypass valve 313 after the change reaches the upper limit set in the currently set mode, the selection unit 2054 changes the calculated opening degree from the lower limit to the upper limit. Change the mode to the mode one level below. On the other hand, when the calculated opening degree of the bypass valve 313 reaches the lower limit set in the currently set mode, the selection unit 2054 sets the calculated opening degree after the change. Change the mode to a higher mode including the lower limit to the upper limit.

  Further, the target high pressure value calculation unit 2051 acquires information on the opening degree of the electronic expansion valve 241 set by each mechanism control unit 2055 of the use-side control unit 205 at this time, and opens the opening degree of the electronic expansion valve 241. Is a maximum upper limit value (for example, 800 pls; a value lower than the opening degree indicating the fully opened state of the electronic expansion valve 241, and an upper limit value for ensuring the normal operation of the electronic expansion valve 241. Two electronic expansion valves 241 with an opening of 480 pls are provided in parallel, and can be opened up to 480 × 2 = maximum 960 pls according to the required opening. A timer incorporated in the target high pressure value calculation unit 2051 indicates whether or not the state of 800 pls satisfies the condition that the state of being continued for a predetermined time (for example, 3 hours). (S12) and the electronic expansion valve 241 When the state in which the degree is the maximum value continues for a predetermined time (YES in S12), the target high pressure value calculation unit 2051 calculates A = f (Hz, m in the above equation (2). ) = a * Compressor Step + b is changed to A = f (Hz, m) = a * Compressor Step + b + aa (S13). That is, the target high pressure value calculation unit 2051 increases the target high pressure value A by the value of aa when the above conditions of S12 are satisfied, for example, as shown in FIG. To be calculated. The target high pressure value calculation unit 2051 adds aa by 0.5 each time the above condition of S12 is satisfied (changes to aa = aa + 0.5, where aa is 4.0 at the maximum). That is, every time the above condition of S12 is satisfied, the target high pressure value A and the opening degree of the bypass valve 313 are changed by a new calculation formula, and the heat source side control unit 301 changes the state of the bypass valve 313. The opening calculated with the new calculation formula.

  If the target high pressure value calculation unit 2051 determines that a predetermined time (for example, 24 seconds) has elapsed after S13 (YES in S14), the process returns to S2. The process shown in the flowchart is continued until an operation stop instruction for the air conditioner 1 is input to the operation panel by the operator.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, in the above-described embodiment, an example in which two compressors 21 and 22 are provided in the usage-side unit 2 is shown, but the number of compressors is not limited. For example, even in the usage-side unit 2 provided with one inverter type compressor, the respective opening degrees of the motor-operated valve 311, the electromagnetic valve 312 and the bypass valve 313 shown in FIG. It is possible to apply this invention by changing suitably to the value according to the drive frequency of a machine, and the local piping length.

  Moreover, in the said embodiment, although each valve opening degree of the refrigerant | coolant amount adjustment mechanism 31 of the heat-source side unit 3 is calculated by the utilization side control part 205 which makes a part of the whole control part 500, the said refrigerant | coolant amount adjustment | control is carried out. The calculation of each valve opening of the mechanism 31 may be performed by transmitting information necessary for the calculation from the use side control unit 205 to the heat source side control unit 301 and using the heat source side control unit 301. One control mechanism that functions as both the side control unit 205 and the heat source side control unit 301 (whether the control mechanism is disposed in the use side unit 2 or the heat source side unit 3 or in a separate device) The valve opening degree of the refrigerant amount adjusting mechanism 31 may be calculated.

  Moreover, in the said embodiment, although the example of the air conditioner 1 in which the compression mechanisms 21 and 22 and the high pressure side pressure sensor 202 were provided in the utilization side unit 2 side was shown, the said compression mechanisms 21 and 22 and the high pressure side pressure are shown. The unit in which the sensor 202 is disposed is not limited, and the compression mechanisms 21 and 22 and the high pressure side pressure sensor 202 may be provided on the heat source side unit 3 side.

1 is a schematic configuration diagram of an air conditioner according to an embodiment of the present invention. It is a block diagram which shows schematic structure of the control system and main mechanism of an air conditioner. It is a figure which shows the several step which consists of the combination of the drive frequency and drive state for driving a compressor. It is a block diagram which shows the structure of a heat-source side control part. It is a figure which shows each mode which shows the opening degree of an expansion mechanism. It is a flowchart which shows the flow of the process at the time of the opening-and-closing drive control of the expansion mechanism in the heat source side unit of an air conditioner. It is a figure which shows the relationship between compressor performance, a target high pressure value, and local piping length with a graph.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioner 10 Refrigerant circuit 101 Use side refrigerant circuit 101a Bypass circuit 102 Heat source side refrigerant circuit 2 Use side unit 21,22 Compressor 23 Use side heat exchanger 24 Expansion mechanism 241 Electronic expansion valve 242 Electromagnetic valve 243 Bypass valve 201 Low pressure Sensor 202 High pressure sensor 205 User side control unit 2051 Target high pressure value calculation unit 2052 Opening degree calculation unit 2053 Mode storage unit 2054 Selection unit 2055 Control unit 206 Drive control circuit 207 Inverter control circuit 208 Pipe length input unit 3 Heat source side unit 31 Refrigerant amount Adjustment mechanism 311 Electric valve 312 Solenoid valve 313 Bypass valve 32 Heat source side heat exchanger 301 Heat source side control units 6 and 7 Connecting piping

Claims (6)

A use side unit (2) including a use side heat exchanger (23) and an expansion mechanism (24), a heat source side heat exchanger (32), and a refrigerant amount adjustment mechanism (31), and the refrigerant amount adjustment mechanism (31 ) Varies the amount of refrigerant that bypasses the motor-operated valve (311), the electromagnetic valve (312), and the heat source side heat exchanger (32) that changes the amount of refrigerant that passes through the heat source side heat exchanger (32). Refrigerant having a bypass valve (313 ) and flowing through the heat source side heat exchanger (32) by varying the opening degree of the motor-operated valve (311), electromagnetic valve (312) and bypass valve (313) It is connected by the heat-source side unit you adjust the amount (3) are communication pipes (6, 7), detecting the pressure of the refrigerant in the high pressure side of the compression mechanism (21, 22) and the compression mechanism (21, 22) A high pressure side pressure sensor (202) is an air conditioner (1) provided in either the use side unit (2) or the heat source side unit (3),
A pipe length input section (208) into which the local pipe length of the communication pipe (6, 7) is input by an operator;
A target for calculating a target high pressure value according to the drive frequency of the compression mechanism (21, 22) held in advance and the value of the local pipe length input to the pipe length input unit (208) by an operator. High pressure value calculation unit (2051),
Based on the difference between the target high pressure value calculated by the target high pressure value calculation unit (2051) and the high pressure value detected by the high pressure side pressure sensor (202), the bypass valve of the refrigerant quantity adjusting mechanism (31) An opening calculation unit (2052) for calculating the opening of (313) ;
A mode storage unit (2053) for storing a plurality of modes consisting of combinations of respective opening degrees of the electric valve (311), the electromagnetic valve (312) and the bypass valve (313);
A selection unit that selects a mode corresponding to the detected high pressure value from a plurality of modes stored in the mode storage unit (2053) based on the high pressure value detected by the high pressure side pressure sensor (202). (2054) and
The motor-operated valve (311), the solenoid valve according to the respective opening degrees of the motor-operated valve (311), the solenoid valve (312) and the bypass valve (313) indicated by the mode selected by the selector (2054) (312) and a control unit (301) for controlling the respective opening degrees of the bypass valve (313) ,
The control unit (301) performs control to change the mode when the high pressure value detected by the high pressure side pressure sensor (202) is not within a predetermined range, while the high pressure value is within the predetermined range. When it is, without changing the mode, to control the opening of the bypass valve (313) using the opening calculated by the opening calculation unit (2052),
An air conditioner characterized by that . The target high pressure value calculation unit (2051) calculates the target high pressure value when the mode selected by the selection unit (2054) is the same as the previous mode that has already been set, and the calculated The opening calculation unit (2052) calculates the opening of the bypass valve (313) using the target high pressure value, and the control unit (301) uses the calculated opening to calculate the bypass valve (313 The air conditioner according to claim 1 , wherein the air conditioner is controlled to be opened and closed. The mode selected by the selection unit (2054) is the same as the previous mode that has already been set, and the opening degree of the refrigerant amount adjusting mechanism (31) is calculated by the opening degree calculation unit (2052), When the controller (301) controls opening and closing of the refrigerant amount adjusting mechanism (31) using the calculated opening, when the opening of the bypass valve (313) reaches an upper limit or a lower limit The selection unit (2054) newly selects another mode in which the opening degree of the bypass valve (313) is within the range from the lower limit value to the upper limit value, and the control unit (301) newly selects the new mode. The motor operated valve (311), the electromagnetic valve (312), and the bypass valve (312) according to the respective opening degrees of the motor operated valve (311), the electromagnetic valve (312) and the bypass valve (313) indicated by The air conditioner according to claim 2 , wherein the opening degree of each of (313) is controlled. When the absolute value of the difference between the target high pressure value calculated by the target high pressure value calculation unit (2051) and the high pressure value detected by the high pressure side pressure sensor (202) is larger than a predetermined value. the air conditioner as claimed in any one of claims 1 to 3 wherein the bypass valve opening degree of the (313), is increased by the amount determined in advance. The control unit (301) is a case where the mode selected by the selection unit (2054) is changed from a previously set mode, and the opening degree of the bypass valve (313) up to that time Is a value that exceeds the upper limit or lower limit of the opening of the bypass valve (313) indicated by the new mode after the change, the opening of the bypass valve (313) is changed to the value after the change. on the new mode is changed to the opening of the upper or lower limit shown in any of claims 1 to 4 for opening and closing controls the refrigerant amount adjusting mechanism (31) including the bypass valve (313) The air conditioner described in Crab. An expansion mechanism control unit (2055) for controlling the opening degree of the valve constituting the expansion mechanism (24) of the utilization side unit (2),
The target high pressure value calculation unit (2051) is configured such that the opening degree of the valve constituting the expansion mechanism (24) obtained from the expansion mechanism control unit (2055) ensures the normal operation of the expansion mechanism (24). If it is determined that the state of the upper limit value continues for a predetermined time, the target high pressure value is calculated by increasing the predetermined high pressure value, and the calculated target high pressure value The opening calculation unit (2052) calculates the opening of the refrigerant amount adjustment mechanism (31) using the control unit (301), the control unit (301) using the calculated opening, the refrigerant amount adjustment mechanism ( The air conditioner according to any one of claims 2 to 5 , which controls opening and closing of 31).

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