JP2011075120A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner free from frosting by improving the flow division of a refrigerant flowing in a flow divider tube of an indoor heat exchanger, and suppressing the degradation in a cooling capacity. <P>SOLUTION: This air conditioner has the indoor heat exchanger with the plurality of flow divider tubes in which the refrigerant flows, in parallel with each other, an indoor blower distributing the air to the indoor heat exchanger, and a movable panel controlling the flow rate of the indoor air flowing in the plurality of flow divider tubes. In a case when poor flow division occurs in part of the plurality of flow divider tubes, the opening of the movable panel is adjusted to change the balance of air volume of suction air exchanging heat with the indoor heat exchanger, so that the flow division of the refrigerant in the flow divider tube having poor flow division is improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air conditioner, and more particularly, to an air conditioner that improves the deterioration of the refrigerant diversion generated in an evaporator.

  Conventionally, an air conditioner is provided with an indoor heat exchanger in which a plurality of refrigerant branch pipes are provided in parallel in an indoor unit, and during cooling, the indoor air is exchanged with the indoor heat exchanger serving as an evaporator, Air is cooled to cool the air.

  During such cooling operation, the refrigerant flows into the diversion pipe unevenly depending on the operating conditions such as outside air temperature, compressor rotation speed, air filter clogging, etc. As a result, there is a problem in that the heat exchange temperature is reduced due to pressure loss in the shunt pipe, and condensation occurs near the air outlet or the cooling capacity is reduced.

  Therefore, in order to improve the non-uniform flow of the refrigerant generated in the shunt pipe, an inlet of the shunt pipe in the flow direction of the refrigerant during cooling operation is arranged on the windward side of the heat exchanger into which the air that has passed through the air filter flows. An air conditioner has been proposed (see, for example, Patent Document 1).

  Further, when the rotational speed of the indoor blower in the cooling operation is reduced, dew is generated near the cold air outlet of the indoor unit. Therefore, an air conditioner that controls the rotational speed of the fan of the indoor blower to a rotational speed at which dew does not occur is provided. It has been proposed (see, for example, Patent Document 2).

JP 2000-213764 A JP-A-3-207954

  However, the thing of patent document 1 is what improved the number and assembly method of a shunt pipe, and when the variable speed operation | movement is carried out according to a load using an inverter apparatus according to a load, and air-conditioning capability is made variable. Even if the shunt pipe and pressure reducing means are adjusted according to the rated operation, the shunting of the refrigerant flowing in the shunt pipe deteriorates during the maximum capacity operation and the minimum capacity operation under load conditions other than the rated operation, and the cooling capacity decreases. There is a problem to do.

  Moreover, since the thing of patent document 2 performs control of prevention of dew condensation, there exists a possibility that a cooling capability may fall.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide an air conditioner that improves the flow of refrigerant flowing in the flow dividing pipe, does not decrease the cooling capacity, and has no dew.

  In order to achieve the above-described object, an air conditioner according to the present invention includes an indoor heat exchanger in which a plurality of flow-dividing pipes through which a refrigerant flows are provided in parallel in an indoor unit, and an indoor blower that blows air to the indoor heat exchanger And a movable panel for controlling the flow rate of the indoor air flowing through the plurality of branch pipes, and when the refrigerant branch flow deterioration occurs in a part of the plurality of branch pipes, the movable panel is opened. And a control means for improving the diversion of the refrigerant in the diversion pipe whose diversion deteriorates by adjusting the degree of air flow and changing the air volume balance of the intake air that exchanges heat with the indoor heat exchanger.

  According to the air conditioner according to the present invention, it is possible to improve the diversion of the refrigerant flowing in the diversion pipe, suppress the decrease in cooling capacity, and provide an air conditioner without dew.

The refrigerating cycle figure used for the air conditioner of this invention. The longitudinal cross-sectional view in the branch flow favorable state of the indoor unit used for the air conditioner of this invention. The longitudinal cross-sectional view in the branch flow deterioration state of the downstream branch pipe of the indoor unit used for the air conditioner of this invention. The longitudinal cross-sectional view in the branch flow deterioration state of the upper branch pipe of the indoor unit used for the air conditioner of this invention. The control block diagram used for the air conditioner of this invention. The flowchart figure of the opening degree adjustment of the movable panel used for the air conditioner of this invention.

  An embodiment of an air conditioner according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, an air conditioner 1 according to this embodiment includes an outdoor unit 2 and an indoor unit 3.

  In the outdoor unit 2, a compressor 4, a four-way valve 5, an outdoor blower 6, an outdoor heat exchanger 7, and an expansion valve 8 are accommodated by pipe connection. Although not shown, the compressor is operated at a variable speed according to the air conditioning load by the inverter device.

  The indoor unit 3 houses an indoor blower 9 and an indoor heat exchanger 10.

  The high-temperature and high-pressure gas refrigerant compressed by the compressor 4 is sent to an outdoor heat exchanger 7 as a condenser via a four-way valve 5, where it is condensed and liquefied by heat exchange with the outside air. The refrigerant is a liquid phase refrigerant and is decompressed by the expansion valve 8.

  Further, the refrigerant decompressed by the expansion valve 8 is vaporized by exchanging heat with indoor air in the indoor heat exchanger 10 that functions as an evaporator during cooling, and becomes a low-temperature and low-pressure gas-phase refrigerant.

  The room air is deprived of heat by heat exchange with the liquid phase refrigerant at this time, and the room temperature decreases.

  The gas-phase refrigerant from the indoor heat exchanger 10 is sent again to the suction side of the compressor 4 through the four-way valve 5, and is compressed by the compressor 4, and the same process is repeated.

  The indoor heat exchanger 10 is provided with a plurality of, for example, a first branch pipe 10A and a second branch pipe 10B in parallel, through which a refrigerant flows.

A first temperature sensor S ₁ for detecting a refrigerant temperature T _c-1 flowing in the first branch pipe 10A is attached to the first branch pipe 10A, and a second branch pipe 10B includes a second temperature sensor S ₂ for detecting the refrigerant temperature T _c-2 flowing in the second distribution pipe 10B is attached.

Room air intake side in front of the indoor heat exchanger 10, the suction air temperature sensor S _a as a third temperature sensor for detecting the intake air temperature T _a is provided.

  As shown in FIG. 2, the indoor unit 3 accommodates an indoor heat exchanger 10 facing the suction port 11, the heat exchanger 10 is divided into two, and the first shunt pipe 10 </ b> A is in the lower heat exchange. The second shunt pipe 10B constitutes the upper heat exchanger.

  A movable panel 12 is provided to face the suction port 11.

  The upper end 12b of the movable panel 12 is advanced and retracted by the upward / backward moving mechanism 13, and the lower end 12a is advanced / retracted by the downward moving / retracting mechanism 14 independently of the upper end 12b.

The upward / backward moving mechanism 13 is composed of, for example, a rack and pinion that converts a rotational force into a linear motion, and is attached to a side surface of the indoor unit 3 and rotated by a stepping motor (pulse motor) M ₁ (not shown). ), And an upper rack 13r attached to the upper end 12b of the movable panel 12 at one end.

Similarly, the lower forward and reverse mechanism 14 includes a pinion which is rotated by the stepping motor M _2, the forward and backward by the pinion, one end consisting of the lower rack 14r attached to the lower end 12a of the movable panel 12.

  Generally, when a non-uniform flow occurs in the shunt pipe of the indoor heat exchanger of an air conditioner, a dry-out phenomenon occurs in which the refrigerant gasifies at an early stage, and pressure loss occurs in the shunt pipe. As the temperature drops, condensation occurs and the cooling capacity decreases.

  Therefore, the air conditioner 1 adjusts the opening degree of the movable panel 12 to balance the flow rate of air flowing through the indoor heat exchanger 10 (the plurality of branch pipes 10A and 10B), that is, a dry-out phenomenon occurs. The flow rate of air flowing through the shunt pipe is reduced to improve the shunt flow.

  For example, when the dry-out phenomenon due to the deterioration of the diversion does not occur (normal) in the first diversion pipe (lower heat exchanger) 10A and the second diversion pipe (upper heat exchanger) 10B, the movable panel 12 Is controlled such that the upper end 12b of the movable panel 12 is in the forward state and the lower end 12a is also in the forward state so that the amount of air flowing through the heat exchanger is increased and the highly efficient operation is performed.

  As shown in FIG. 3, when the dry-out phenomenon due to the deterioration of the diversion occurs in the first diversion pipe 10A, the upper end 12b is moved forward to reduce the air flow rate to exchange heat with the first diversion pipe 10A. Control is performed so that 12a is in the reverse state. As a result, the efficiency is slightly reduced, but the dry-out phenomenon in the first branch pipe 10A can be solved.

  As shown in FIG. 4, when the dry-out phenomenon due to the worsening of the diversion occurs in the second diversion pipe 10B, the upper end 12b is in the retracted state and the lower end in order to reduce the air flow rate to exchange heat with the second diversion pipe 10B. Control is performed to bring 12a into a forward state. In this case, the dry-out phenomenon in the second branch pipe 10B can be eliminated.

  In this way, the balance of the amount of indoor air flowing through the first branch pipe 10A and the second branch pipe 10B is adjusted according to the dryout phenomenon that occurs in the first branch pipe 10A and the second branch pipe 10B. The dry-out phenomenon can be eliminated.

  As shown in FIG. 5, the indoor unit 3 is provided with an indoor control board 21. The indoor control board 21 includes, for example, an MCU (micro control unit) of the indoor unit 3 which is a control unit for controlling the indoor unit 3. ) 22 and various other circuits are attached, and the MCU 22 of the indoor unit 3 is connected to a power source through a power circuit having a rectifier and the like.

  The MCU 22 of the indoor unit 3 includes a CPU, a memory, and the like, and the CPU executes a control program stored in the ROM while exchanging data with the ROM and the RAM.

  Further, the MCU 22 of the indoor unit 3 is connected to a serial circuit, and signals from an outdoor unit control circuit (not shown) that controls the operation of the compressor 4 and the outdoor fan 6 shown in FIG. Make a transmission. The MCU 22 of the indoor unit 3 detects the room temperature and the like, calculates the air conditioning load, determines the rotational speed of the compressor 4 and the outdoor blower 6, and transmits this data signal to the outdoor unit control circuit via the serial circuit. . The outdoor unit control circuit including the inverter device performs PWM control of the DC voltage of the rectifier circuit to convert DC into AC, and the compressor motor built in the compressor is set to a rotation speed designated by the MCU 22 of the indoor unit 3. Variable speed drive so that

Further, an indoor fan drive circuit 23 that drives and controls the indoor blower 9 is connected to the MCU 22, and a first motor drive circuit 24 that drives and controls the stepping motor M ₁ of the upward and backward movement mechanism 13, and a downward and backward movement mechanism 14. the second motor drive circuit 25 for driving and controlling the stepping motor M ₂ are connected.

In addition, the MCU 22, the first temperature sensor _{S 1,} temperature information signal a second temperature sensor _{S 2} and the suction air temperature sensor _{S a} has been detected is input.

  Further, a driving operation signal is sent to the MCU 22 from the remote controller 30, and the driving is controlled based on this content.

  Next, the processing of the MCU 22 and the operation of the present air conditioner will be described along the operation flow diagram of the movable panel shown in FIG.

  Here, the cooling operation mode will be described as an example.

  The user operates the temperature setting button of the remote controller 30 to set a desired desired temperature, and presses the cooling operation button to instruct the air conditioner to operate in the cooling operation mode. The temperature and cooling operation command signals are transmitted to the MCU 22 of the indoor unit 3.

  The set temperature is stored in the memory by the MCU 22. An indoor temperature sensor installed in the indoor unit 3 detects the temperature of the air sucked into the indoor unit 3, and determines the rotational speed of the compressor 4 and the outdoor blower 6 based on the difference from the set temperature and the amount of change over time. Control the cooling operation.

The first temperature sensor S _1, the first distribution pipe (lower heat exchanger) refrigerant temperature T _c-1 10A is detected by the second temperature sensor S _2, the second distribution pipe (upper heat exchanger) refrigerant temperature _{T c-2} and 10B is detected by the suction air temperature sensor _{S a,} the indoor air inlet temperature _{T a} is _detected, the temperature information signal _{T c-1, T c-} 2, T a is It is transmitted to the MCU 22.

T _c-1, it receives the temperature information signal _{T c-2, T a} MCU22 is whether the first refrigerant temperature _{T c-1} is or lower than the first predetermined temperature (first threshold) a Judgment is made (S1).

The first predetermined temperature a, where is a value corresponding to the indoor temperature T _a, is obtained in advance by a test.

When the refrigerant temperature T _c-1 is lower than the first predetermined temperature value a (YES in S1), the average temperature T _{c-ave of} the plurality (n) refrigerant temperatures T _cn (where T _c-ave = T _c−n / n), for example, the absolute value of the difference between the average temperature T _c−ave = (T _c−1 + T _c−2 ) / 2 and the refrigerant temperature T _c−1 of the first branch pipe 10A is the second value. It is determined whether the temperature is higher than a predetermined temperature (second threshold value) b (S2).

When the absolute value of the difference between the average temperature T _c-ave and the refrigerant temperature T _c-2 is higher than the second predetermined temperature b (YES in S2), the refrigerant temperature T _c-2 is lower than the first predetermined temperature a. Whether or not (S3).

When the refrigerant temperature _Tc-2 is not lower than the first predetermined temperature a (NO in S3), it is determined that a dry-out phenomenon has occurred in the middle of the first branch pipe 10A, and as shown in FIG. The lower end 12a of the movable panel 12 is set in the retracted state, and the upper end 12b is set in the advanced state (S4).

  As a result, the amount of air flowing into the first branch pipe 10A is reduced, the flow rate of the refrigerant flowing through the first branch pipe 10A is adjusted, and the dry-out phenomenon in the middle of the first branch pipe 10A is eliminated. The cooling operation is performed and the room temperature is adjusted to a desired value.

  The amount of air flowing into the first branch pipe 10A is reduced, the flow rate of the refrigerant flowing through the first branch pipe 10A is adjusted, the dry-out phenomenon in the middle of the first branch pipe 10A is eliminated, and the branch flow is improved. Do.

  Similar steps are repeated in this state.

In step S3, when the refrigerant temperature T _c-2 is lower than the first predetermined temperature a (YES in S3), the absolute difference between the average temperature T _c-ave and the refrigerant temperature T _c-2 of the second shunt pipe 10B. It is determined whether or not the value is higher than a second predetermined temperature b (S5).

When the refrigerant temperature _Tc-2 is higher than the second predetermined temperature b (YES in S5), it is determined that a dryout phenomenon has occurred between the first branch pipe 10A and the second branch pipe 10B. Such a phenomenon occurs infrequently, and the current state is maintained, and finally the refrigeration cycle balances and waits for the dryout phenomenon to be resolved.

When the absolute value of the difference between the average temperature T _c-ave and the refrigerant temperature T _c-2 of the second branch pipe 10B is not greater than the second predetermined temperature b (NO in S5), the second branch pipe 10B It is determined that there is no dryout phenomenon in the middle, and the operation in step S4 is continued.

In step S1, when the refrigerant temperature T _c-1 is not lower than the first predetermined temperature a (NO in S1), the absolute value of the difference between the average temperature T _c-ave and the refrigerant temperature T _c-1 is the second value. When it is not higher than the predetermined temperature b (NO in S2), it is determined whether or not the refrigerant temperature _Tc-2 is lower than the first predetermined temperature a (S6).

When the refrigerant temperature T _c-2 is lower than the first predetermined temperature value a (YES in S6), the absolute value of the difference between the average temperature T _c-ave and the refrigerant temperature T _c-2 of the second shunt pipe 10B is It is determined whether the temperature is higher than the second predetermined temperature b (S7).

When the absolute value of the difference between the average temperature T _c-ave and the refrigerant temperature T _c-2 is higher than the second predetermined temperature b (YES in S7), a dryout phenomenon occurs in the middle of the second shunt pipe 10B. As shown in FIG. 4, the lower end 12a of the movable panel 12 is moved forward and the upper end 12b is moved backward (S8).

  As a result, the amount of air flowing into the second branch pipe 10B is reduced, the flow rate of the refrigerant flowing through the second branch pipe 10B is adjusted, and the dry-out phenomenon in the middle of the second branch pipe 10B is eliminated. The cooling operation is performed and the room temperature is adjusted to a desired value.

In step S6, when the refrigerant temperature T _c-2 is not lower than the second predetermined temperature b (NO in S6), and in step S7, the absolute value of the difference between the refrigerant temperatures T _c-2 of the second branch pipe 10B However, when the temperature is not higher than the second predetermined temperature b (NO in S7), it is determined that the dryout phenomenon does not occur between the first branch pipe 10A and the second branch pipe 10B, and is shown in FIG. Thus, the movable panel 12 keeps the upper end 12b of the movable panel 12 in the forward state and the lower end 12a in the forward state (S9).

  As described above, in the indoor heat exchanger, this air conditioner detects the branch pipe where the refrigerant branch flow deteriorates and the dry-out phenomenon occurs by detecting the refrigerant temperature by the refrigerant temperature sensor at an early stage. By adjusting the opening, the air volume balance of the air flowing into the indoor heat exchanger is changed to improve the diversion to a plurality of diversion pipes.

  Thereby, the pressure loss due to the dry-out phenomenon of the shunt pipe can be prevented, the occurrence of condensation due to the decrease in the heat exchange temperature can be eliminated, and the cooling capacity can be prevented from decreasing.

  According to the air conditioner of the present embodiment, the flow of the refrigerant flowing in the branch pipe of the indoor heat exchanger is improved, the cooling capacity is prevented from being lowered, and an air conditioner without dew is realized.

  In the above embodiment, an example in which an indoor heat exchanger composed of two shunt pipes and one movable panel is used has been described. However, the air conditioner includes an indoor heat exchanger composed of three or more shunt pipes, One or more movable panels may be used.

DESCRIPTION OF SYMBOLS 1 ... Air conditioner, 2 ... Outdoor unit, 3 ... Indoor unit, 4 ... Compressor, 5 ... Four-way valve, 6 ... Outdoor fan, 7 ... Outdoor heat exchanger, 8 ... Expansion valve, 9 ... Indoor fan, 10 ... Indoor heat exchanger, 10A ... first shunt tube, 10B ... second shunt tube, 11 ... suction port, 12 ... movable panel, 12a ... lower end, 12b ... upper end, 13 ... up-and-down mechanism, 13r ... upper rack, DESCRIPTION OF SYMBOLS 14 ... Downward movement mechanism, 14r ... Lower rack, 21 ... Indoor control board, 22 ... MCU, 23 ... Indoor fan drive circuit, 24 ... 1st motor drive circuit, 25 ... 2nd motor drive circuit, 30 ... Remote control, M ₁ ... stepping motor, M ₂ ... stepping motor, S ₁ ... first temperature sensor, S ₂ ... second temperature sensor, S _a ... suction air temperature sensor.

Claims (2)

In the indoor unit, an air conditioner including an indoor heat exchanger in which a plurality of shunt pipes through which refrigerant flows is provided in parallel, and an indoor fan that blows air to the indoor heat exchanger,
A movable panel for controlling the flow rate of the indoor air flowing through the plurality of shunt pipes;
When the refrigerant diversion worsens in some of the plurality of diversion pipes, the opening of the movable panel is adjusted to change the air volume balance of the intake air that exchanges heat with the indoor heat exchanger, and the diversion deteriorates. And an air conditioner characterized by comprising control means for improving the flow of the refrigerant in the flow dividing pipe.   The control means detects a refrigerant temperature with a temperature sensor provided for each of the plurality of flow dividing pipes, detects a flow dividing pipe that has deteriorated flow, and executes control for adjusting the opening of the movable panel. The air conditioner according to claim 1, wherein

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