JP2014119154A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner which can vary the amount of a refrigerant circulating in a refrigerant circuit so as to increase operation efficiency and has high safety even if stopping operating owing to a sudden power failure during operation.SOLUTION: There is provided an air conditioner in which a refrigerant amount control part 10 provided in parallel with a throttle device 5 constituting a refrigerant circuit includes a receiver 13 which reserves a refrigerant, a first connection pipe 14 connecting the receiver 13 to piping 11 and a second connection pipe 15 connecting the receiver 13 to piping 12, and a first flow rate control device 16 and a second flow rate control device 17 interposed in the first connection pipe 14 and a second connection pipe 15 and adjusting flow rates of the refrigerant. At least one of the first flow rate control device 16 and second flow rate control device 17 has a structure which is not fully opened.

Description

  The present invention relates to an air conditioner capable of adjusting the amount of refrigerant circulating in a refrigerant circuit.

  Most current air conditioners have a refrigerant circuit configured to switch between cooling and heating. Also, the amount of refrigerant required for the refrigerant circuit varies greatly depending on the size of the condenser. In a general air conditioner, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger that constitute the refrigerant circuit The volume of is different. Therefore, the amount of refrigerant required for the refrigerant circuit varies greatly between the cooling operation and the heating operation. Even in the same operation mode, the amount of refrigerant required for the refrigerant circuit varies depending on whether the rotation speed of the compressor is high or low.

  In response to the above problem, Patent Document 1 includes a refrigerant storage device connected in flow communication with the refrigerant circuit by at least one refrigerant line, and a refrigerant flow control device arranged in at least one refrigerant line. The refrigerant flow control device is described as a refrigerant vapor compression system having an open position where the refrigerant flows through the refrigerant line and a closed position where the flow of the refrigerant passing through the refrigerant line is blocked.

JP 2011-521194 A

  However, in Patent Document 1, since the refrigerant flow control device is controlled to be in the open position only when the required refrigerant amount is adjusted, air conditioning is performed due to a power failure or the like during air conditioner operations such as cooling operation or heating operation. When supply of power to the machine stops, the refrigerant may be sealed in the refrigerant storage device. Therefore, when the refrigerant storage device is sealed in a state where the refrigerant is filled and the state continues for a long time under the hot sun, the refrigerant in the refrigerant storage device expands (liquid expansion or liquid refrigerant gasification). Very high pressure will be applied. There is a possibility that the refrigerant flow control device is overloaded and breaks down, or the refrigerant leaks out of the refrigerant circuit from the receiver, and the reliability of the air conditioner deteriorates.

  Therefore, in the present invention, in view of the above, it is possible to change the amount of refrigerant circulating in the refrigerant circuit in order to improve the operation efficiency, and a power failure or the like suddenly occurs during the operation of the air conditioner, An object of the present invention is to provide a highly reliable air conditioner even when the operation of the air conditioner is stopped due to supply interruption.

  In order to achieve the above object, in the present invention, a compressor, a condenser, a throttling device, and an evaporator are sequentially connected by a pipe to form a refrigerant circuit through which refrigerant flows, and the amount of refrigerant flowing through the refrigerant circuit is adjusted. A refrigerant amount adjustment unit is provided in parallel with the expansion device, and the refrigerant amount adjustment unit stores a refrigerant using a pressure of the refrigerant flowing from the high-pressure side pipe before and after the expansion device to the low-pressure side pipe, and the receiver And a high-pressure side connecting pipe that connects the high-pressure side pipe, a low-pressure side connecting pipe that connects the receiver and the low-pressure side pipe, and a refrigerant that is interposed in the high-pressure side connecting pipe and the low-pressure side connecting pipe, respectively. An air conditioner including a high pressure side flow rate adjustment device and a low pressure side flow rate adjustment device for adjusting a flow rate, and a control device for controlling the opening degree of the high pressure side flow rate adjustment device and the low pressure side flow rate adjustment device is provided, Previous Controller, characterized by the opening adjustment so as not to fully close at least one of the high-pressure side flow control device and the low-flow control device.

  According to the above configuration, the controller adjusts the opening degree so that at least one of the high pressure side flow rate adjustment device and the low pressure side flow rate adjustment device is not fully closed during the air conditioner operation. Even if the supply of power to the air conditioner is interrupted due to a power failure while the receiver is full of refrigerant while the air conditioner is in operation, such as heating operation, The accumulated refrigerant returns to the refrigerant circuit through a flow rate adjustment device that does not fully close, that is, an open flow rate adjustment device. Therefore, a highly safe air conditioner can be obtained without increasing the capacity of the receiver more than necessary.

  The flow rate adjusting device that is not fully closed may be a low pressure side flow rate adjusting device. That is, when the air conditioner is configured to be capable of cooling and heating, the opening degree may be adjusted so as not to fully close the low-pressure flow rate adjusting device in each operation mode. Thereby, when the compressor is suddenly stopped due to a power failure, the refrigerant accumulated in the receiver due to the refrigerant pressure difference can be discharged more smoothly into the refrigerant circuit.

  The control device is configured to input the set temperature, the room temperature detected by the room temperature sensor, and the outside air temperature detected by the outside air temperature sensor, based on the operation condition data stored in advance, the compressor rotation speed, the throttle device , The opening of the high pressure side flow control device and the opening of the low pressure flow control device may be controlled.

  Specifically, first, the optimum rotation speed of the compressor and the opening of the expansion device are determined according to the set temperature, room temperature, and outside air temperature. Then, the opening degrees of the high-pressure side flow control device and the low-pressure side flow control device are obtained so that the optimum refrigerant amount is obtained under the condition that at least one of the flow control devices is not fully closed. The operating condition data obtained in this way is stored in the memory of the control device, and according to the input set temperature, room temperature and outside air temperature, based on the operating condition data, the rotational speed of the compressor, the opening degree of the expansion device, The opening degree of both flow rate adjusting devices is controlled.

  Here, the optimum refrigerant amount is the “air conditioning” of the refrigerant amount (circulating refrigerant amount) that actually circulates in the refrigerant circuit obtained by subtracting the refrigerant amount stored in the receiver from the refrigerant amount enclosed in the refrigerant circuit. It means the amount of refrigerant that maximizes the COP (coefficient of performance) represented by “capacity” / “power consumption”.

  There may be a difference between the refrigerant amount adjusted by the control device controlling the opening degree of the high-pressure side flow rate adjustment device and the low-pressure side flow rate adjustment device and the refrigerant amount actually circulating in the refrigerant circuit. . Therefore, it may be checked whether the refrigerant amount adjusted by the control device is deviated from the optimum refrigerant amount.

  Specifically, when the control device determines that the operation state is stable, the opening degree of the high-pressure side flow control device and the low-pressure side flow control device according to the outlet temperature of the condenser and the outlet temperature of the evaporator. Adjust the opening. That is, the value of the degree of supercooling and the degree of superheat is determined in a refrigerant circuit in which the amount of refrigerant circulating is constant at the optimum amount of refrigerant and the environmental conditions, the rotation speed of the compressor, and the opening of the expansion device are constant. These values serve as a reference value for the degree of supercooling (reference degree of supercooling) and a reference value for the degree of superheating (reference degree of superheat) in the optimum refrigerant amount. On the other hand, the actual degree of supercooling can be determined by measuring the temperature at the outlet of the condenser, and the actual degree of superheat can be determined by measuring the temperature at the outlet of the evaporator.

  Therefore, the difference between the reference value of the supercooling degree and the actual measurement value, the difference between the reference value of the superheat degree and the actual measurement value, and the opening degree of the high pressure side flow rate adjustment device necessary to eliminate these temperature differences. The adjustment value and the adjustment value of the opening degree of the low pressure side flow rate adjustment device are obtained in advance by experiments, and the data is stored in the control device. In this way, the control device determines the opening degree and the low-pressure side flow rate of the high-pressure side flow control device based on the data obtained by the control device in the experiment according to the actual temperature at the condenser outlet and the actual temperature at the evaporator outlet. By adjusting the opening of the adjusting device, it is possible to accurately adjust to the optimum refrigerant amount.

  It is good also as a flow control device of the structure which does not fully close at least one among a high pressure side flow control device and a low pressure side flow control device. Thereby, the opening degree can be adjusted so that at least one of the high-pressure side flow rate adjusting device and the low-pressure side flow rate adjusting device is not fully closed.

  As described above, the air conditioner of the present invention includes a high-pressure side flow control device and a low-pressure device connected to the high-pressure side connecting tube and the low-pressure side connecting tube connected to the receiver, respectively, in the refrigerant amount adjusting unit provided in parallel with the expansion device. A control device for controlling the opening degree of the high pressure side flow rate adjustment device and the low pressure side flow rate adjustment device is provided, and at least one of the high pressure side flow rate adjustment device and the low pressure side flow rate adjustment device is provided by the control device. Since the opening is adjusted so as not to be fully closed, it is possible to return the refrigerant from the receiver to the refrigerant circuit even if the operation of the air conditioner stops suddenly due to the interruption of the power supply to the air conditioner due to a power failure etc. .

The figure which shows the refrigerant circuit of the air conditioner of this invention Control block diagram of the air conditioner of the present invention Flow chart of air conditioning operation when the thermo is off Control flow chart of flow rate adjusting device when thermo is off The schematic diagram which shows another aspect of a refrigerant | coolant adjustment part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram showing an embodiment of an air conditioner according to the present invention. As illustrated, the air conditioner of the present embodiment is a single-type air conditioner in which one indoor unit 2 is connected to one outdoor unit 1, and includes a compressor 3 housed in the outdoor unit 1, an outdoor unit The heat exchanger 4 and the expansion device 5 are connected in series in this order by refrigerant piping, and further, the indoor heat exchanger 7 accommodated in the indoor unit 2 is connected by piping from the expansion device 5 through the two-way valve 6, The refrigerant circuit is configured by connecting the pipe from the heat exchanger 7 to the outdoor compressor 3 through the three-way valve 8 again.

  The compressor 3 is connected to the refrigerant circuit via a four-way valve 9 that is a switching valve. By switching the four-way valve 9, either direction of the outdoor heat exchanger 4 side or the indoor heat exchanger 7 side is selected. The compressed refrigerant can be sent out. By switching the four-way valve 9, the outdoor heat exchanger 4 and the indoor heat exchanger 7 are used as a condenser or an evaporator.

  Specifically, in FIG. 1, the high-temperature refrigerant discharged from the compressor 3 is circulated in the direction indicated by the solid line in the figure, and passes through the outdoor heat exchanger 4 as a condenser and the expansion device 5 and the indoor heat as an evaporator. Cooling operation is realized by flowing into the exchanger 7. In addition, the refrigerant discharged from the compressor 3 is circulated in the direction of the broken arrow shown in the figure, and flows into the outdoor heat exchanger 4 as an evaporator via the indoor heat exchanger 7 as a condenser and the expansion device 5. By this, heating operation is realized.

  In the present invention, the refrigerant amount adjusting unit 10 that adjusts the amount of refrigerant flowing through the refrigerant circuit is connected in parallel with the expansion device 5. The refrigerant amount adjusting unit 10 includes a receiver 13 that accumulates refrigerant using the pressure of the refrigerant flowing through the pipes 11 and 12 before and after the expansion device 5, a first connection pipe 14 that connects the receiver 13 and the pipe 11, and the receiver 13. A second connecting pipe 15 that connects the pipe 12, a first flow rate adjusting device 16 that is interposed in the first connecting pipe 14, and a second flow rate adjusting device 17 that is interposed in the second connecting pipe 15 are provided. ing.

  As the size of the receiver 13, the volume difference between the maximum amount and the minimum amount of the optimum refrigerant amount that can fluctuate depending on the air conditioning operation may be used as the internal volume of the receiver as it is. When the liquid refrigerant stored in 13 is expanded or gasified, there is a space for pressure to escape, so the reliability is improved. Therefore, in order to improve the operation efficiency by changing the optimum refrigerant amount according to the operation conditions, it is better to set the volume to at least one time based on the volume difference between the maximum amount and the minimum amount of the optimum refrigerant amount. .

  In the refrigerant circuit, the upstream side in the refrigerant flow direction of the expansion device 5 has a high pressure, and the downstream side in the refrigerant flow direction of the expansion device 5 has a low pressure. That is, during the cooling operation, the pipe 11 is a high-pressure side pipe, the pipe 12 is a low-pressure side pipe, the first connection pipe 14 is a high-pressure side connection pipe, the second connection pipe 15 is a low-pressure side connection pipe, and the first flow rate adjustment device 16. Is the high pressure side flow control device, and the second flow control device 17 is the low pressure side flow control device. On the other hand, during the heating operation, the pipe 12 is the high pressure side pipe, the pipe 11 is the low pressure side pipe, the second connecting pipe 15 is the high pressure side connecting pipe, the first connecting pipe 14 is the low pressure side connecting pipe, and the second flow rate adjusting device. Reference numeral 17 denotes a high-pressure side flow control device, and the first flow control device 16 serves as a low-pressure side flow control device.

  As shown in FIG. 2, the air conditioner includes a control device 20 that controls the operation of the refrigeration circuit and controls the air conditioning operation. In the air conditioner, a temperature sensor 21 that detects an outlet temperature of the outdoor heat exchanger 4, a temperature sensor 22 that detects an outlet temperature of the indoor heat exchanger 7, and a discharge temperature of the refrigerant discharged from the compressor 3 are detected. A discharge temperature sensor 23, a room temperature sensor 24, and an outside air temperature sensor 25 are provided.

  The control device 20 is composed of a microcomputer equipped with a CPU, a memory, and the like. Based on outputs of these temperature sensors, remote controllers, operation signals of operation switches of the main body, and the like according to a desired air conditioning operation, the compressor 3, The operation of the refrigerant circuit is controlled by controlling the operations of the blower 26, the expansion device 5, the first flow rate adjusting device 16, and the second flow rate adjusting device 17.

  The control device 20 includes an indoor control unit provided in the indoor unit 2 and an outdoor control unit provided in the outdoor unit 1. The indoor control unit and the outdoor control unit are connected so as to be communicable with each other, and both cooperate to control operations of the indoor unit 2 and the outdoor unit 1.

  When the air conditioning operation starts, the control device 20 sets a target rotational speed of the compressor 3 based on the set temperature and room temperature, and determines the opening degree of the expansion device 5 according to the target rotational speed. The control device 20 controls the compressor 3, the expansion device 5, the blower 26, and the like so that the room temperature becomes the set temperature in accordance with the determined operating conditions.

  And the control apparatus 20 will perform refrigerant | coolant amount adjustment control so that it may become the optimal refrigerant | coolant amount, if an air-conditioning driving | operation is started and the driving | operation of the compressor 3 is started. A part of the refrigerant filled in the refrigerant circuit is accumulated in the receiver 13, and the remaining refrigerant circulates in the refrigerant circuit. In the refrigerant amount adjustment control, the first flow rate adjusting device 16 and the first flow rate adjusting device 16 are controlled according to the operation conditions such as the type of air conditioning operation (cooling operation, heating operation), discharge temperature, compressor rotation speed, room temperature, outside air temperature, and set temperature. The opening degree of the two flow rate adjusting device 17 is set.

  Generally, the capacity of the outdoor heat exchanger 4 is larger than the capacity of the indoor heat exchanger 7. Therefore, more refrigerant is required during the cooling operation. Also in the present embodiment, the optimum refrigerant amount during the cooling rated operation is set to be larger than the optimum refrigerant amount during the heating rated operation. Here, the rated operation means an operation in which the rotation speed of the compressor is driven at a preset constant value. As the rotation speed of the compressor, a standard rotation speed is set with high operation efficiency between the minimum rotation speed and the maximum rotation speed. That is, the cooling operation and the dehumidifying operation are the air conditioning operation with a large amount of the optimum refrigerant, and the heating operation is the air conditioning operation with a small amount of the optimum refrigerant.

  When performing the refrigerant amount adjustment control, the control device 20 determines the opening amounts of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 on the basis of the current operation state, and the first opening amount is set so as to be the determined opening amount. The flow rate adjusting device 16 and the second flow rate adjusting device 17 are controlled. In addition, the opening degree of the first flow rate adjusting device 16 and the second flow rate adjusting device 17 according to the operation state is determined in advance by experiments or the like and stored in the memory. During the air conditioning operation, the control device 20 reads the opening amounts of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 according to the current operation status from the memory, and the first flow rate adjustment device 16 according to the read opening degree. And the second flow rate adjusting device 17 is operated.

  The expansion device 5 is a device that adjusts the flow rate of the refrigerant. In this embodiment, an expansion valve is used. However, the expansion device 5 is not limited thereto, and a plurality of capillary tubes may be arranged to switch the flow path. The first flow rate adjusting device 16 and the second flow rate adjusting device 17 control the flow of the refrigerant in the first connecting pipe 14 and the second connecting pipe 15 by opening and closing.

  That is, the first flow rate adjusting device 16 and the second flow rate adjusting device 17 adjust the pressure of the refrigerant in the receiver 13, and use an expansion valve, a flow rate adjustment valve, a stop valve, and the like. In the present embodiment, the first flow rate adjusting device 16 and the second flow rate adjusting device 17 are configured to use the same type of needle valve and to accurately control the opening degree by the stepping motor with the fully open position as a reference.

  The refrigerant amount adjustment control is executed from the time when the operation of the compressor 3 is started. That is, when an operation instruction is input such as when an operation signal is received from the remote controller or when a reservation time is reached due to timer reservation, the control device 20 starts the air conditioning operation and operates the compressor 3. At this time, the control device 20 determines the opening degrees of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 based on the operation state. At the start of this operation, the type of air conditioning operation is confirmed as the operation status. The control device 20 determines the type of air conditioning operation to be started based on the operation signal from the remote controller or timer reservation information.

  The control device 20 performs control so that at least one of the high pressure side flow rate adjustment device and the low pressure side flow rate adjustment device is not fully closed during the air conditioning operation. In the present embodiment, control is performed so that at least the first flow rate adjusting device 16 is not fully closed. That is, since the optimum refrigerant amount is set to be larger in the cooling rated operation than in the heating rated operation, the receiver 13 is filled with the refrigerant in the heating operation mode. In this state, even if the supply of power to the air conditioner suddenly stops due to a power failure or the like, even if the air conditioner stops, the first flow rate adjustment device 16 that is the low pressure side flow rate adjustment device is not fully closed, The refrigerant in the receiver 13 can be smoothly returned to the refrigerant circuit by the pressure difference.

Of course, the second flow rate adjusting device 17 may be controlled not to be fully closed. Further, when the optimum refrigerant amount is set to be larger during the heating rated operation than during the cooling rated operation, the second flow rate adjusting device 17 may be controlled not to be fully closed.
With the above control, the refrigerant cannot be sealed in the receiver 13 during the air conditioning operation. Therefore, when the compressor 3 is driven, it is necessary to adjust the refrigerant amount in the receiver 13 by adjusting the opening degree of the first flow rate adjusting device 16 and the second flow rate adjusting device 17.

  Specifically, the control device 20 determines the optimum rotation speed of the compressor and the opening degree of the expansion device in accordance with the set temperature, the room temperature, and the outside air temperature. Then, the opening amounts of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 are obtained by experiments or the like so that the optimum refrigerant amount is obtained under the condition that at least one flow rate adjustment device is not fully closed.

  The operating condition data obtained in this way is stored in the memory of the control device 20. During the air conditioning operation, the control device 20 reads the opening amounts of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 according to the current operation status from the memory, and the first flow rate adjustment device 16 according to the read opening degree. And the second flow rate adjusting device 17 is operated.

  When the heating operation mode is executed, the pipe 12 is a high-pressure side pipe, the second connection pipe 15 is a high-pressure side connection pipe, and the second flow rate adjustment device 17 is a high-pressure side flow rate adjustment apparatus. The pipe 11 becomes a low-pressure side pipe, the first connecting pipe 14 becomes a low-pressure side connecting pipe, and the first flow rate adjusting device 16 becomes a low-pressure side flow rate adjusting apparatus.

  At this time, the opening degree of the second flow rate adjusting device 17 that is the high pressure side flow rate adjusting device is made larger than the opening degree of the first flow rate adjusting device 16 that is the low pressure side flow rate adjusting device, or the second flow rate adjusting device 17. Is opened and the first flow rate adjusting device 16 is closed, whereby the refrigerant accumulates in the receiver 13. The control device 20 maintains the relationship between the opening amounts of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 and sets the predetermined amount of opening obtained by experiments to allow surplus refrigerant to enter the receiver 13. It is possible to obtain the optimum refrigerant amount at the time of reservoir and heating rated operation.

  On the other hand, when the cooling operation mode is executed, the pipe 11 becomes a high-pressure side pipe, the first connection pipe 14 becomes a high-pressure side connection pipe, and the first flow rate adjustment device 16 becomes a high-pressure side flow rate adjustment apparatus. Then, the pipe 12 becomes a low pressure side pipe, the second connecting pipe 15 becomes a low pressure side connecting pipe, and the second flow rate adjusting device 17 becomes a low pressure side flow rate adjusting apparatus.

  At this time, the opening degree of the first flow rate adjustment device 16 that is the high pressure side flow rate adjustment device is made smaller than the opening degree of the second flow rate adjustment device 17 that is the low pressure side flow rate adjustment device, or the second flow rate adjustment device 17 is opened. The first flow rate adjusting device 16 is closed. The control device 20 maintains the relationship between the opening amounts of the first flow rate adjusting device 16 and the second flow rate adjusting device 17 and sets the required opening amount obtained by experiment to a necessary amount of refrigerant in the refrigerant circuit. The amount of circulating refrigerant can be increased by that amount, and the optimum amount of refrigerant in the cooling rated operation can be obtained.

  As described above, the air conditioning capacity is increased by controlling the first flow rate adjusting device 16 and the second flow rate adjusting device 17 so that the refrigerant circulating in the refrigerant circuit has the optimum refrigerant amount from the start of the air conditioning operation. Can do. Therefore, driving efficiency is improved and energy-saving driving can be realized.

  As another method for determining the type of air-conditioning operation, the type of air-conditioning operation started based on room temperature is determined. The control device 20 acquires room temperature information from the room temperature sensor 24 when an operation instruction from a remote controller or the like is input. The control device 20 determines the type of air conditioning operation based on the current room temperature. The timing for discriminating the type of the air-conditioning operation based on the room temperature is set before the start of the operation after the operation instruction is input or immediately after the start of the operation.

  The current room temperature T is compared with the first specified temperature Tw and the second specified temperature Tc (Tw <Tc). When the current room temperature T is equal to or lower than the first specified temperature Tw (T ≦ Tw), the control device 20 determines that the heating operation is being performed. When the current room temperature T is equal to or higher than the second specified temperature Tc (T ≧ Tc), the control device 20 determines that the cooling operation is being performed.

  In the case of Tw <T <Tc, the control device 20 determines that it is a blowing operation. In the case of the air blowing operation, the control device 20 operates the air blower 26 of the indoor unit 2. Since the control of the refrigeration cycle is not performed, the refrigerant amount adjustment control is not performed. Note that the first flow rate adjusting device 16 and the second flow rate adjusting device 17 are opened. Thus, the method of discriminating the type of the air-conditioning operation based on the room temperature is useful when the automatic operation for automatically selecting the cooling operation or the heating operation according to the room temperature is performed.

  When performing the air conditioning operation for cooling or heating, when the operation of the compressor 3 is started, the temperature of the refrigerant discharged from the compressor 3 gradually increases. When the discharge temperature becomes substantially constant, the operation of the refrigerant circuit, that is, the air conditioning operation is stabilized. After the air conditioning operation is stabilized, the control device 20 continues the refrigerant amount adjustment control.

  When the circulating refrigerant amount is the optimum refrigerant amount, the environmental conditions, the compressor speed and the opening of the throttle device are constant, and the air conditioning operation is stable, the refrigerant condensing temperature / evaporating temperature, the degree of supercooling (standard overcooling) The value of the degree of cooling) and the degree of superheat (reference superheat degree) are determined. In the cooling operation, the outdoor heat exchanger 4 serves as a condenser, and the indoor heat exchanger 7 serves as an evaporator. During the heating operation, the indoor heat exchanger 7 serves as a condenser, and the outdoor heat exchanger 4 serves as an evaporator.

  After the air-conditioning operation is stabilized, the control device 20 calculates the actual value of the degree of supercooling and the actual value of the degree of superheat by measuring the outlet temperature of the condenser and the outlet temperature of the evaporator. And when there is a difference between these measured values and the reference supercooling degree and the reference superheat degree, the opening degree of the first flow rate adjusting device 16 and the second flow rate adjusting device 17 is set so that the temperature difference is eliminated. adjust.

  Specifically, the difference between the outlet temperature of the condenser and the reference supercooling degree, the difference between the outlet temperature of the evaporator and the reference superheat degree, and the first flow rate adjustment device necessary to eliminate these temperature differences 16 and the adjustment value of the opening degree of the second flow rate adjusting device 17 are obtained in advance by experiments, and the data is stored in the control device 20. As a result, the control device 20 determines the first flow rate adjusting device 16 and the second flow rate based on the data obtained by the control device 20 in the experiment according to the actual temperature at the condenser outlet and the actual temperature at the evaporator outlet. By adjusting the opening degree of the adjusting device 17, it is possible to accurately adjust the optimum refrigerant amount.

  If there is a temperature difference between the room temperature and the set temperature during the air conditioning operation, the control device 20 changes the rotation speed of the compressor 3 and the opening degree of the expansion device 5 so that the temperature difference becomes small. At this time, the control device 20 adjusts the opening degree of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 according to the rotation speed of the compressor 3, the outside air temperature, and the like. For example, when the rotation speed of the compressor 3 increases, the control device 20 decreases the opening of the high-pressure flow rate adjustment device 6 or increases the opening of the low-pressure flow adjustment device 7 so that the optimum refrigerant amount increases. Enlarge.

  As shown in FIG. 3, the room temperature reaches the set temperature after a certain amount of time has elapsed after the start of the air conditioning operation. The control device 20 stops the compressor 3 and operates only the blower 26. And if a temperature difference arises between room temperature and preset temperature, the control apparatus 20 will start the driving | operation of the compressor 3 again. In this way, during the air conditioning operation, the thermo-off that repeats the on / off operation of the compressor 3 is performed.

  The refrigerant amount adjustment control is also performed when the thermostat is off. The control device 20 adjusts the opening degree of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 when the compressor 3 starts operation when the thermostat is off. The opening degree of the first flow rate adjusting device 16 and the second flow rate adjusting device 17 is adjusted according to the rotational speed of the compressor 3.

  That is, when the compressor 3 is stopped due to thermo-off, the control device 20 stores the rotational speed of the compressor 3 and the opening degrees of the first flow rate adjusting device 16 and the second flow rate adjusting device 17 before the stop in the memory. Then, when starting the operation of the compressor 3, the control device 20 determines the number of rotations of the compressor 3 based on the current room temperature, and the first flow rate adjustment device 16 and the second flow rate adjustment device according to this rotation number. An opening of 17 is set.

  As shown in FIG. 4, the air conditioning operation is performed with the rotation speed of the compressor 3 being A, and the opening amounts of the first flow rate adjusting device 16 and the second flow rate adjusting device 17 being a1 and a2. When the room temperature reaches the set temperature, the control device 20 stops the compressor 3 and performs the air blowing operation. When the room temperature changes and a temperature difference occurs between the room temperature and the set temperature, the control device 20 starts the operation of the compressor 3. The control device 20 determines the rotation speed B of the compressor 3 according to the temperature difference between the room temperature and the set temperature, and determines the opening degrees of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 according to this rotation speed. . The control device 20 may also stop the air blowing operation when the compressor 3 is stopped. In this case, when the room temperature changes and a temperature difference occurs between the room temperature and the set temperature, the control device 20 resumes the air conditioning operation (the operation of the compressor 3 and the air blowing operation).

  When the rotation speed A before the stop of the compressor 3 and the rotation speed B at the start of operation are the same, the opening degree of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 is the same as the opening degree before the operation stop. Is done. The opening degree of each first flow rate adjusting device 16 and second flow rate adjusting device 17 is fixed to a1 and a2, respectively. In this case, the operation of the compressor 3 is restarted with the opening as it is, without fully opening the throttle device 5, the first flow rate adjusting device 16, and the second flow rate adjusting device 17.

  Thus, since it is not necessary to adjust the opening degree of the expansion device 5 or the like, the operation of the compressor 3 can be started immediately, and the time until the room temperature is set to the set temperature can be shortened. In addition, since the operating conditions do not change, the optimum refrigerant amount can be obtained immediately, efficient operation can be performed, and energy can be saved.

  When the rotation speed A before the stop of the compressor 3 and the rotation speed B at the start of operation are different, the opening degree of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 is changed from the opening degree before the operation stop. The opening amounts are b1 and b2, respectively. The control device 20 opens the first flow rate adjustment device 16 and the second flow rate adjustment device 17 once to balance the pressure in the refrigerant circuit, and then operates the compressor 3 with the determined opening degree. Thereafter, the air conditioning operation is performed until the room temperature reaches the set temperature. For example, when the rotation speed of the compressor 3 increases, the control device 20 decreases the opening of the high-pressure side flow control device and increases the opening of the low-pressure flow control device so that the optimum refrigerant amount increases.

Thus, the room temperature can be quickly set to the set temperature by adjusting the opening of the first flow rate adjusting device 16 and the second flow rate adjusting device 17 according to the rotation speed of the compressor 3 at the start of operation of the compressor 3. Can improve user comfort. Moreover, the time for which the compressor 3 is stopped becomes longer, and an energy saving operation can be realized.

  By the way, when there is a change in the operating status during the air conditioning operation, the control device 20 controls the first flow rate adjusting device 16 and the second flow rate adjusting device 17 in accordance with the change in the operating status. In particular, the opening amounts of the first flow rate adjusting device 16 and the second flow rate adjusting device 17 are adjusted according to the outside air temperature detected by the outside air temperature sensor 25.

  When the outside air temperature at the start of operation of the compressor 3 changes from the outside air temperature when the compressor 3 is stopped, the control device 20 determines the rotation speed of the compressor 3 based on the outside air temperature and the room temperature. For example, during the cooling operation, when the outside air temperature rises, the rotational speed of the compressor 3 is increased more than the rotational speed before stopping. According to this rotational speed, the opening degree of the first flow rate adjustment device 16 that is the high-pressure side flow rate adjustment device is reduced so that the optimum refrigerant amount of the refrigerant circulating in the refrigerant circuit is increased, and thus the low-pressure side flow rate adjustment device. The opening degree of the second flow rate adjusting device 17 is increased.

  Similarly, when the outside air temperature decreases, the opening amounts of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 are adjusted so that the optimum refrigerant amount decreases. Similarly, in the heating operation, the opening amounts of the first flow rate adjustment device 16 and the second flow rate adjustment device 17 are adjusted so that the optimum refrigerant amount increases or decreases according to the change in the outside air temperature.

In this way, by adjusting the opening degree of the first flow rate adjusting device 16 and the second flow rate adjusting device 17 in accordance with the change in the outside air temperature, the refrigerant is circulated in the refrigerant circuit with an optimal amount of refrigerant even if the operating state changes. Circulate. Therefore, efficient operation can be performed and energy saving can be achieved.

  In the present embodiment, the first flow rate adjusting device 16 is controlled so as not to be fully closed. Accordingly, if a flow rate adjusting device having a structure that is not fully closed is used as the first flow rate adjusting device 16, it is possible to reliably prevent the first flow rate adjusting device 16 from being fully closed. As a flow control device with a structure that does not fully close, specifically, a valve body that is physically stopped before the fully closed position to secure a gap between the valve body and the valve seat, or a valve body By providing a notch or the like in itself, a structure that ensures the circulation of the refrigerant in the fully closed position can be used. It goes without saying that the second flow rate adjusting device 17 is controlled not to be fully closed, and the second flow rate adjusting device 17 may be a flow rate adjusting device having a structure that is not fully closed.

  The present invention is not limited to the above embodiment, and many modifications and changes can be made to the above embodiment within the scope of the present invention. Specifically, in the above embodiment, one end side of the first connecting pipe 14 and the second connecting pipe 15 is connected to the pipes 11 and 12 of the refrigerant circuit, respectively, and the other end side is individually connected to the receiver 13. Not limited to this, for example, as shown in FIG. 5, after the other end sides of the first connecting pipe 14 and the second connecting pipe 15 are assembled, it is possible to connect to the receiver 13 as a single connecting pipe. It is.

  Further, to determine whether the air-conditioning operation is stable, the compressor 3 and the discharge temperature are detected, and it is determined that the change is stable when the detected temperature change is within a certain range within a predetermined time. Not limited to this, for example, it may be determined that the temperature is stable when the temperature change of the outlet temperature of the condenser or the evaporator is within a certain range within a predetermined time.

DESCRIPTION OF SYMBOLS 1 Outdoor unit 2 Indoor unit 3 Compressor 4 Outdoor heat exchanger 5 Throttle device 6 Two-way valve 7 Indoor heat exchanger 8 Three-way valve 9 Four-way valve 10 Refrigerant amount adjustment part 11 Pipe 12 Pipe 13 Receiver 14 First connection pipe 15 1st Two connection pipes 16 First flow rate adjusting device 17 Second flow rate adjusting device 20 Control device 21 Temperature sensor 22 Temperature sensor 23 Discharge temperature sensor 24 Room temperature sensor 25 Outside air temperature sensor 26 Blower

Claims (4)

  A compressor, a condenser, a throttling device, and an evaporator are sequentially connected by a pipe to form a refrigerant circuit through which refrigerant flows, and a refrigerant amount adjusting unit that adjusts the amount of refrigerant flowing through the refrigerant circuit is provided in parallel with the throttling device. The refrigerant amount adjusting unit is configured to connect a receiver that collects refrigerant by using a pressure of refrigerant flowing from a high-pressure side pipe before and after the expansion device to a low-pressure side pipe, and a high-pressure side connection that connects the receiver and the high-pressure side pipe. A low-pressure side connecting pipe that connects the pipe and the receiver and the low-pressure side pipe, and a high-pressure side flow adjusting device and a low-pressure side that are interposed in the high-pressure side connecting pipe and the low-pressure side connecting pipe, respectively. An air conditioner including a flow rate adjusting device, wherein a controller for controlling the opening degree of the high pressure side flow rate adjusting device and the low pressure side flow rate adjusting device is provided, and the control device includes a high pressure side flow rate adjusting device and a low flow rate adjusting device. An air conditioner characterized by the opening adjustment so as not to fully close at least one of the side flow rate adjusting device.   The controller is configured to input the set temperature, the room temperature detected by the room temperature sensor, and the outside air temperature detected by the outside air temperature sensor, based on the operation condition data stored in advance, the rotation speed of the compressor, The air conditioner according to claim 1, wherein the opening degree of the throttle device, the opening degree of the high pressure side flow rate adjustment device, and the opening degree of the low pressure side flow rate adjustment device are controlled.   When it is determined that the operation state is stable, the control device opens the high-pressure side flow control device and opens the low-pressure side flow control device according to the outlet temperature of the condenser and the outlet temperature of the evaporator. The air conditioner according to claim 2, wherein the degree is adjusted.   The air conditioner according to any one of claims 1 to 3, wherein at least one of the high-pressure side flow rate adjustment device and the low-pressure side flow rate adjustment device is a flow rate adjustment device that is not fully closed.

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