JP2005016946A - Multi-chamber type air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent splashing of dew or lowering in ability caused by uneven temperature distribution of an indoor heat exchanger. <P>SOLUTION: A multi-chamber type air conditioner comprises: a suction temperature detection means detecting a suction temperature of a compressor; an evaporating temperature detection means detecting an evaporating temperature of an evaporating temperature generating circuit; gas pipe temperature detection means detecting gas pipe temperatures at outlets of each indoor heat exchanger; and a suction SH calculation means calculating suction SH (superheat) from output values of the suction temperature detection means and the evaporating temperature detection means. The multi-chamber type air conditioner further comprises: a gas pipe temperature tolerance calculation means for determining the minimum gas pipe temperature from the gas pipe temperatures detected by the gas pipe temperature detection means; a suction SH calculation means; and an electronic expansion valve opening control means calculating and controlling correction opening of an electronic expansion valve so that a value calculated by the gas pipe temperature tolerance calculation means is within a range of a target value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multi-type air conditioner that can perform a cooling operation and a heating operation by operating a plurality of indoor units with one outdoor unit.

(Conventional example 1)
FIG. 14 is a refrigerant circuit diagram of a conventional multi-type air conditioner, in which 1 is a compressor that compresses refrigerant, 2 is a four-way valve that is connected to the compressor 1 and switches the refrigerant flow to a cooling or heating cycle. 3 is an outdoor heat exchanger, one of which is connected to the four-way valve 2, 4a to 4c are a plurality of electronic expansion valves branched in parallel from the main circuit, and 5a to 5c are connected to the electronic expansion valves 4a to 4c. And the other is an indoor heat exchanger connected to the four-way valve 2 of the main circuit, 6 is an accumulator provided between the four-way valve 2 and the compressor 1, and 7 is an evaporation temperature provided for measuring the evaporation temperature. It is a capillary of the generation circuit. A bypass circuit is formed between the discharge pipe of the compressor 1 and the inlet pipe of the accumulator 6 and includes the capillary tubes 8 and 10 and the electromagnetic valve 9 sandwiched between them.

Next, the operation will be described. In the conventional multi-type air conditioner shown in FIG. 14, when the operation of the compressor 1 is stopped, the solenoid valve 9 of the bypass circuit is opened, and the electronic expansion valves 4a to 4c are opened to the maximum opening, whereby the refrigerant is rapidly discharged. To make the pressure in the refrigerant circuit uniform by balancing the high and low pressures more quickly, thereby facilitating the next start-up.
However, since the bypass circuit is connected to the inlet side of the accumulator 6, when the solenoid valve 9 is opened when the compressor 1 is stopped, the high-pressure refrigerant flows through the bypass circuit, and the refrigerant liquid accumulated in the accumulator 6 flows into the compressor. The refrigerant liquid is accumulated in the compressor 1 by being pushed out by 1.
Further, when the electronic expansion valves 4a to 4c are opened to the maximum opening degree when the compressor 1 is stopped, the refrigerant in the indoor heat exchangers 5a to 5c operating as an evaporator during cooling operation rapidly moves to the accumulator 6, The accumulator 6 overflows and the refrigerant accumulates in the compressor 1.

(Conventional example 2)
FIG. 15 is a refrigerant circuit diagram showing another conventional multi-type air conditioner, and reference numerals 1 to 3, 4 a to 4 c, and 5 a to 5 c are the same as those in the first conventional example, and the description thereof is omitted. Reference numerals 13a to 13c denote two-way valves provided on the side opposite to the electronic expansion valves of the indoor heat exchangers 5a to 5c, reference numeral 14 denotes an intake refrigerant temperature sensor provided on the intake pipe of the compressor 1 for detecting the intake refrigerant temperature, and 15a to 15c. 15c is an evaporating temperature sensor for cooling operation, 18 is an evaporating temperature sensor for heating operation, 20 is a multi-controller, and the electronic expansion valves 4a to 4c and the two-way valves 13a to 13c are arranged in the multi-controller 20 part. ing.

Next, the operation will be described. The detection signals of the suction temperature sensor 14 and the evaporation temperature sensors 15a to 15c, 18 are sent to the arithmetic unit of the multi-controller 10, and the multi-controller 10 determines the cooling air based on the difference between the intake refrigerant temperature of the compressor 1 and the evaporation temperature of the evaporator. The degree of superheat of the suction gas at the time of heating and heating is detected, and the degree of superheat is controlled by determining the opening degree of the electronic expansion valves 4a to 4c based on the result.
Especially in the case of cooling operation, the indoor heat exchangers 5a to 5c operate as evaporators, but the refrigerant temperatures differ in the respective circuits near the outlets of the indoor heat exchangers 5a to 5c, but in the superheat control, this portion There is no control.
Utility Kaihei 4-113860 JP-A-62-252862 JP-A-3-59351

Since the conventional multi-type air conditioner is configured as described above, it has the following problems.
1. Problems of Conventional Example 1 (1) When the compressor 1 is stopped, the bypass circuit is opened and the refrigerant liquid in the accumulator 6 is accumulated in the compressor 1. When restarting in this state, the lubricating oil in the compressor 1 is taken out to the outside. Since the lubricating oil is insufficient, the life of the compressor 1 is reduced.
(2) Since the electronic expansion valve 4 is opened to the maximum when the compressor 1 is stopped, the refrigerant in the evaporator rapidly moves to the accumulator 6, and the refrigerant overflows from the accumulator 6 and accumulates in the compressor 1. At the same time, the refrigerant noise caused by the rapid movement of the refrigerant becomes noise.
(3) Since the restart is performed after the pressure difference between the discharge side and the suction side of the compressor 1 becomes sufficiently small, it takes a long time to reach a stable state after the restart.
2. Problems of Conventional Example 2 (1) Superheat control is performed at the temperatures of the inlet side of the indoor heat exchangers 5a to 5c and the suction pipe of the compressor 1 during the cooling operation, so the indoor heat exchangers 5a to 5c (evaporation) The temperature of the refrigerant in each of the branch circuits is different for each branch circuit, and when the extension pipe is used or the indoor load fluctuates, even if the superheat degree of the suction pipe of the compressor 1 after merging is appropriate, Some refrigerants are too superheated before merging, in which case the temperature distribution of the indoor heat exchanger is not uniform and a temperature gradient occurs, and the temperature of the blown air also varies. Problems such as reduced capacity are likely to occur.

The present invention has been made to solve the above-described problems, and its object is as follows.
(1) The refrigerant liquid is prevented from accumulating in the compressor when the compressor is stopped, and a shortage of lubricating oil at the start-up is prevented, thereby aiming to extend the life of the compressor.
(2) Refrigerant noise generated by refrigerant movement when the compressor is stopped is prevented.
(3) When the compressor is stopped, liquid refrigerant flows from the outdoor heat exchanger through the evaporation temperature generation circuit and flows into the accumulator and is prevented from overflowing.
(4) Prevent dew owing to uneven temperature distribution of the indoor heat exchanger and decrease in capacity.

  The multi-room air conditioner according to the present invention is capable of switching between heating and cooling, in which a compressor, a four-way valve, an outdoor heat exchanger, an accumulator, and an evaporation temperature generation circuit are sequentially connected to constitute a refrigerant circuit including a double pipe heat exchanger. For detecting the intake temperature of a compressor in a multi-room air conditioner having an outdoor unit and an indoor unit having an electronic expansion valve and an indoor heat exchanger connected between branch pipes branched in parallel from the main circuit A temperature detecting means, an evaporating temperature detecting means for detecting the evaporating temperature of the evaporating temperature generating circuit, a gas pipe temperature detecting means for detecting an outlet gas pipe temperature of each indoor heat exchanger, an intake temperature detecting means and an evaporating temperature detecting means. An intake SH calculation means for calculating the intake SH (superheat degree) of the compressor from the output value, a minimum one of the gas pipe temperatures detected by the gas pipe temperature detection means is determined, and the minimum value and each gas pipe temperature are determined. Gas pipe to calculate the difference between An electronic expansion valve opening that calculates and controls the correction opening degree of the electronic expansion valve so that the values calculated by the degree tolerance calculation means, the suction SH calculation means, and the gas pipe temperature tolerance calculation means fall within the target value range. And a degree control means.

  The multi-room air conditioner according to the present invention can prevent the indoor heat exchanger from being exposed and the ability from being lowered due to the above configuration.

Embodiment 1 FIG.
(Outline of Embodiment 1)
While the air conditioner is stopped, the air conditioner generally opens the electronic expansion valve to equilibrate the high and low pressures in preparation for the next start-up. However, in order to accelerate the rise of the cooling (heating) operation after restarting, it is better not to move the refrigerant in the condenser or the evaporator by closing the electronic expansion valve or setting it to the minimum opening degree when stopping. In that case, since the high and low pressures are not balanced, the compressor is difficult to start at the time of restart, but if it is possible to start differential pressure, such as a scroll compressor, it can be started even when high and low pressure are not balanced Become. However, in a severe state in midsummer, the high / low pressure difference is large, and even a compressor capable of starting differential pressure may not be started. For this reason, a Vaspy circuit for balancing high and low pressures is provided, but if a bypass circuit is connected upstream of the accumulator as in the past, the liquid refrigerant in the accumulator is pushed out by the compressor and accumulates in the compressor, causing various adverse effects. give. Therefore, in this embodiment, the bypass circuit is connected to the downstream side of the accumulator to prevent the liquid refrigerant in the accumulator from being pushed out to the compressor when the bypass circuit operates to balance high and low pressures. .

Embodiment 1 of the present invention will be described below. FIG. 1 is a refrigerant circuit diagram of an air conditioner according to Embodiment 1 of the present invention. In the figure, reference numerals 1 to 7 are the same as those of a conventional apparatus, and the description thereof is omitted. Reference numeral 12 denotes a double pipe heat exchanger for exchanging heat between the liquefied high-pressure refrigerant and the gas pipe side refrigerant to obtain a large subcool. An important point different from the conventional apparatus is that a bypass circuit composed of the capillaries 8 and 10 and the electromagnetic valve 9 is connected to the outlet side of the accumulator 6.
The compressor 1, the four-way valve 2, the electronic expansion valves 4a to 4c, and the electromagnetic valve 9 are controlled by signals from a control board 20 (microcomputer) as shown in FIG.

Next, the operation will be described. During operation of the compressor 1, the solenoid valve 9 of the bypass circuit is closed and the bypass circuit does not operate. In the flowchart of FIG. 3, when the switch is turned off in step 30, the compressor 1 is stopped (step 31). Subsequently, in step 32, the electronic expansion valves 4a to 4c are closed to the minimum opening, and each heat exchanger is closed. Prevent the refrigerant from moving. Then, for the purpose of facilitating restart, the solenoid valve 9 of the bypass circuit is opened, and the high-pressure refrigerant gas is caused to flow to the suction side of the compressor 1 to balance the discharge side and suction side of the compressor 1 (step 33). At this time, since the refrigerant that has passed through the bypass circuit does not pass through the accumulator 6, the refrigerant liquid in the accumulator 6 does not flow into the compressor 1.
As described above, in this embodiment, the electronic expansion valves 4a to 4c are closed to the minimum opening degree when the compressor 1 is stopped in order to speed up the start-up of the operation after the start-up. Although a compressor of the type is suitable, since a high-low pressure balance is forcibly performed by a bypass circuit in order to ensure start-up, for example, a rotary compressor that is not suitable for differential pressure start-up can be used.
In addition, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are not fully closed, and the minimum opening is set to the minimum opening degree when the air conditioner is not used and the state is fully closed for a long time. It is because it may become defective.

  According to this embodiment, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are closed to the minimum opening, and the bypass circuit provided for facilitating start-up to balance high and low pressures is used as the compressor. 1 is connected from the discharge side of the accumulator 6 to the outlet side of the accumulator 6, so that the liquid refrigerant in the accumulator 6 is not pushed out to the compressor 1 when the bypass circuit is operated, and the lack of lubricating oil when the compressor 1 is restarted is prevented. Can do.

  A multi-room air conditioner according to the present invention includes a compressor, a four-way valve, an outdoor heat exchanger, an accumulator, an outdoor unit capable of switching between heating and cooling, which constitutes a refrigerant circuit by sequentially connecting an evaporation temperature generation circuit, and a main circuit. In a multi-chamber air conditioner having an electronic expansion valve and an indoor unit to which an indoor heat exchanger is connected between the branch pipes branched in parallel, provided between the compressor and the four-way valve and between the compressor and the accumulator. A bypass circuit having a solenoid valve that is closed during the operation of the compressor, and a control means that closes the electronic expansion valve to a minimum opening and stops the solenoid valve of the bypass circuit when the compressor is stopped.

  In the multi-chamber air conditioner according to the present invention, when the compressor is stopped, the electronic expansion valve is closed to the minimum degree of opening so that the refrigerant in each heat exchanger is hardly moved, and the bypass valve is opened by opening the solenoid valve. The low pressure is balanced and the liquid refrigerant in the accumulator is not pushed out to the compressor.

  In the multi-chamber air conditioner according to the present invention, the above configuration prevents the liquid refrigerant of the accumulator from being pushed out and collected in the compressor when the compressor is stopped, and prevents the lack of lubricating oil at the time of starting. Long life can be achieved.

Embodiment 2. FIG.
(Outline of Embodiment 2)
In the first embodiment, the electronic expansion valve of the main circuit is closed to the minimum opening degree when the compressor is stopped, but there is a problem of refrigerant noise because there is some movement of the refrigerant in the evaporator (indoor heat exchanger). Remain. Therefore, in this embodiment, the refrigerant sound of the evaporator is eliminated by closing the electronic expansion valve of the main circuit when the compressor is stopped.

  A second embodiment of the present invention will be described below with reference to the drawings. Since the configuration of the refrigerant circuit is exactly the same as that of the first embodiment, the description thereof is omitted.

  Next, the operation will be described with reference to the flowchart of FIG. When the switch is turned off in step 40, the compressor 1 is stopped in step 41, and then in step 42, the electronic expansion valves 4a to 4c are completely closed in order to prevent the refrigerant from moving in each heat exchanger. . Since the refrigerant does not move in the evaporator (indoor heat exchanger) by closing the electronic expansion valves 4a to 4c, no refrigerant noise is generated. In step 43, the solenoid valve 9 of the bypass circuit is opened in order to balance the high and low pressures to facilitate restarting. These are the same as in the first embodiment.

  According to this embodiment, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are completely closed, and further, the solenoid valve 9 of the bypass circuit connected from the discharge side of the compressor 1 to the outlet side of the accumulator 6 is opened. Since it did in this way, while having the same effect as Embodiment 1, the refrigerant | coolant sound in the evaporator (indoor heat exchanger 5a-5c) at the time of the stop of the compressor 1 can be prevented.

  A multi-room air conditioner according to the present invention includes a compressor, a four-way valve, an outdoor heat exchanger, an accumulator, an outdoor unit capable of switching between heating and cooling, which constitutes a refrigerant circuit by sequentially connecting an evaporation temperature generation circuit, and a main circuit. In a multi-chamber air conditioner having an electronic expansion valve and an indoor unit to which an indoor heat exchanger is connected between the branch pipes branched in parallel, provided between the compressor and the four-way valve and between the compressor and the accumulator. A bypass circuit having a solenoid valve closed during operation of the compressor and a control means for closing the electronic expansion valve and stopping the solenoid valve of the bypass circuit when the compressor is stopped.

  In the multi-chamber air conditioner of the present invention, the refrigerant of each heat exchanger does not move by closing the electronic expansion valve when the compressor is stopped, and the high and low pressures are balanced by opening the electromagnetic valve of the bypass circuit, And the liquid refrigerant of an accumulator is not pushed out to a compressor.

  In the multi-chamber air conditioner according to the present invention, the above configuration prevents the liquid refrigerant of the accumulator from being pushed out and collected in the compressor when the compressor is stopped, and prevents the lack of lubricating oil at the time of starting. The service life can be extended and refrigerant noise in the indoor heat exchanger can be prevented.

Embodiment 3 FIG.
In the second embodiment, the electronic expansion valves 4a to 4c are completely closed when the compressor 1 is stopped. However, when the air conditioner is not used for a long time, the electronic expansion valves 4a to 4c remain closed. Therefore, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are closed, and then the solenoid valve 9 is opened to balance the high and low pressures. May be opened at a predetermined opening. A flowchart in this case is shown in FIG. A step 44 for opening the electronic expansion valves 4a to 4c to a predetermined opening is added to the flowchart of FIG.

  The multi-chamber air conditioner according to the present invention is characterized in that the control means opens the electronic expansion valve to a predetermined opening after the solenoid valve of the bypass circuit is opened and the high and low pressures are balanced.

  In the multi-chamber air conditioner according to the present invention, the electronic expansion valve is opened to a predetermined opening after high-low pressure equilibrium, so the electronic expansion valve does not remain closed when it is not used for a long time.

  In the multi-chamber air conditioner according to the present invention, the control means is configured to open the electronic expansion valve to a predetermined opening after the solenoid valve of the bypass circuit is opened and the high and low pressures are balanced, so the air conditioner is not used for a long time. In this case, the mechanical malfunction of the electronic expansion valve can be eliminated.

Embodiment 4 FIG.
(Outline of Embodiment 4)
In the first and second embodiments, a capillary tube is used for the evaporation temperature generation circuit. However, in the case of a multi-type air conditioner, for example, if there is an indoor unit that is not used, the remaining refrigerant accumulates in the accumulator and is at the liquid level. Thus, the influence of the liquid refrigerant flowing from the outdoor heat exchanger to the accumulator when the compressor is stopped through the evaporation temperature generation circuit cannot be ignored. In this embodiment, an electronic expansion valve is used in place of the capillary tube of the evaporation temperature generation circuit to prevent this, and liquid refrigerant is prevented from flowing from the outdoor heat exchanger to the accumulator through the evaporation temperature generation circuit when the compressor is stopped. To do.

  Embodiment 4 of the present invention will be described below with reference to the drawings. 6 is a refrigerant circuit diagram of an air conditioner according to Embodiment 4 of the present invention. In the figure, parts other than the reference numeral 11 are the same as those in FIG. 1 of the first embodiment, and the description thereof is omitted. Reference numeral 11 denotes an electronic expansion valve provided in an evaporation temperature generating circuit having one end connected between the outdoor heat exchanger 3 and the electronic expansion valves 4a to 4c and the other end connected to the inlet side of the accumulator.

Next, the operation will be described with reference to the flowchart of FIG. When the switch is turned off in step 50, the compressor 1 is stopped in step 51. Subsequently, for the same purpose as in the first or second embodiment, the electronic expansion valves 4a to 4c are turned to the minimum opening in step 52. Close or close. Further, by closing the evaporation temperature generating electronic expansion valve 11 to the minimum opening in step 53, the liquid refrigerant is prevented from flowing from the outdoor heat exchanger 3 through the evaporation temperature generating circuit into the accumulator 6 as much as possible. Prevent the refrigerant from overflowing. In step 54, the solenoid valve 9 of the bypass circuit is opened to balance the high and low pressures.
The reason why the evaporating temperature generating electronic expansion valve 11 is not fully closed is the same as in the case of the electronic expansion valves 4a to 4c of the first embodiment.

  According to this embodiment, when the compressor 1 is stopped, the electronic expansion valves 4a to 4c are closed to the minimum opening degree or closed to suppress the movement of the refrigerant in each heat exchanger, and the evaporation temperature generation circuit Since the evaporating temperature generating electronic expansion valve 11 is closed to the minimum opening, even if there is an indoor unit that is not used and the liquid level of the accumulator 6 becomes high, the overflow of the refrigerant liquid from the accumulator 6 is suppressed. .

  A multi-room air conditioner according to the present invention includes a compressor, a four-way valve, an outdoor heat exchanger, an accumulator, an outdoor unit capable of switching between heating and cooling, which constitutes a refrigerant circuit by sequentially connecting an evaporation temperature generation circuit, and a main circuit. In a multi-chamber air conditioner having an electronic expansion valve and an indoor unit with an indoor heat exchanger connected between branch pipes branched in parallel, the evaporation temperature generation circuit has an electronic expansion valve for generating an evaporation temperature, and is compressed. Between the compressor and the four-way valve and between the compressor and the accumulator, and closes or closes the electronic expansion valve to the minimum opening when the compressor is stopped, and a bypass circuit having a closed solenoid valve during compressor operation In addition, the electronic expansion valve for generating the evaporation temperature is closed to the minimum opening, and further includes a control means for opening the electromagnetic valve of the bypass circuit.

  In the multi-room air conditioner according to the present invention, the liquid refrigerant moving from the outdoor heat exchanger to the accumulator through the evaporation temperature generation circuit is substantially eliminated by closing the evaporation temperature generation electronic expansion valve to the minimum opening.

  In the multi-chamber air conditioner according to the present invention, with the above configuration, there is no fear that the refrigerant liquid overflows from the accumulator even when excess refrigerant is accumulated in the accumulator, and it is possible to prevent a reduction in the lubricating performance of the compressor.

Embodiment 5 FIG.
In the fourth embodiment, the evaporating temperature generating electronic expansion valve 11 is closed to the minimum opening, but may be completely closed. FIG. 8 shows a flowchart in that case. If it does in this way, the liquid refrigerant which flows into the accumulator 6 through the evaporation temperature production | generation circuit from the outdoor heat exchanger 3 at the time of the stop of the compressor 1 can be eliminated.

  A multi-room air conditioner according to the present invention includes a compressor, a four-way valve, an outdoor heat exchanger, an accumulator, an outdoor unit capable of switching between heating and cooling, which constitutes a refrigerant circuit by sequentially connecting an evaporation temperature generation circuit, and a main circuit. In a multi-chamber air conditioner having an electronic expansion valve and an indoor unit with an indoor heat exchanger connected between branch pipes branched in parallel, the evaporation temperature generation circuit has an electronic expansion valve for generating an evaporation temperature, and is compressed. Between the compressor and the four-way valve and between the compressor and the accumulator, and closes or closes the electronic expansion valve to the minimum opening when the compressor is stopped, and a bypass circuit having a closed solenoid valve during compressor operation A control means for closing the electronic expansion valve for generating the evaporation temperature and further opening the electromagnetic valve of the bypass circuit is provided.

  In the multi-room air conditioner according to the present invention, the liquid refrigerant moving from the outdoor heat exchanger to the accumulator through the evaporation temperature generation circuit is eliminated by closing the evaporation expansion temperature generating electronic expansion valve.

  In the multi-chamber air conditioner according to the present invention, with the above-described configuration, the refrigerant liquid does not overflow from the accumulator even when surplus refrigerant is accumulated in the accumulator, and the lubrication performance of the compressor can be prevented from being lowered.

Embodiment 6 FIG.
Further, after opening the electromagnetic valve 9 of the bypass circuit in the fifth embodiment, as shown in the flowchart of FIG. 9, the high-low pressure balanced post-evaporation temperature generation electronic expansion valve 11 is opened to a predetermined opening in step 65. Accordingly, it is possible to prevent mechanical malfunction of the evaporating temperature generating electronic expansion valve 11 when the air conditioner is not used for a long period of time.

  The multi-room air conditioner according to the present invention is characterized in that the control means opens the solenoid valve of the bypass circuit and opens the evaporating temperature generating electronic expansion valve to a predetermined opening after the high and low pressures are balanced.

  In the multi-chamber air conditioner according to the present invention, the evaporating temperature generating electronic expansion valve is opened to a predetermined opening after high-low pressure equilibration, so that the evaporating temperature generating electronic expansion valve does not remain closed when not used for a long time. .

  The multi-room air conditioner according to the present invention can eliminate the mechanical malfunction of the evaporating temperature generating electronic expansion valve when the air conditioner is not used for a long period of time due to the above configuration.

Embodiment 7 FIG.
(Overview of Embodiment 7)
In this embodiment, a temperature sensor is provided on the gas piping side of each indoor unit to detect each gas pipe temperature, and each indoor outlet SH (superheat degree) is obtained by comparing with the evaporation temperature by the evaporation temperature sensor. A tolerance with respect to the reference value of the other indoor outlets SH is obtained using the minimum value among them as a reference value. And the correction | amendment of the electronic expansion valve of each indoor unit is repeated until each indoor exit SH tolerance enters into the target range also including suction | inhalation SH and discharge temperature. In this way, even when there is a difference in indoor load fluctuation / extension piping, each indoor unit outlet SH is kept within a certain range to prevent the occurrence of dew jumping, capacity reduction, etc. occurring in the indoor unit.

  Embodiment 7 of the present invention will be described below with reference to the drawings. FIG. 10 is a refrigerant circuit diagram of an air conditioner according to Embodiment 7 of the present invention. In the figure, reference numerals 1 to 7 and 14 are the same as those of the conventional apparatus, and the description thereof is omitted. 15 is an evaporation temperature sensor that branches from between the outdoor heat exchanger 3 and the electronic expansion valves 4a to 4c, is connected to the suction side of the compressor 1, and detects the evaporation temperature of the evaporation temperature generation circuit provided with the capillary tube 7. 16a to 16c are gas pipe temperature sensors for detecting the outlet temperatures of the indoor heat exchangers 5a to 5c, 21 is a discharge temperature sensor for detecting the discharge temperature of the compressor 1, and 30 is a controller for controlling the electronic expansion valve.

Next, the operation will be described.
Output values of the suction temperature sensor 14, the evaporation temperature sensor 15, the gas pipe temperature sensors 16a to 16c, and the discharge temperature sensor 21 are input to the controller 30 for controlling the electronic expansion valve, and the electronic expansion valves 4a to 4c are performed according to the procedure described below. The valve opening is controlled.
The contents of the valve opening control will be described. The calculation formulas of the intake SH, each indoor outlet SH (a, b, c), and each indoor outlet SH tolerance (a, b, c) used for the description are (1) to (3) It defines with a formula.

  The contents of the valve opening control will be described with reference to the flowchart of FIG. In step 100, the operation of the indoor unit is started. Next, in step 101, the controller 30 sets the opening degree of the electronic expansion valves 4a to 4c and the initial value of the operation frequency of the compressor 1. In this case, the opening ratio of the electronic expansion valves 4a to 4c is changed by the capacity of the indoor unit. In step 102, it is checked whether the suction SH defined by the equation (1) is within the target value range, and in step 103, the opening correction of the electronic expansion valves 4a to 4c is performed uniformly according to FIG. 13 (a). . Next, in step 104, it is checked whether the discharge temperature is within the target value range, and in step 105, the opening degrees of the electronic expansion valves 4a to 4c are each uniformly corrected according to FIG. 13 (b). After the process of step 105 is finished, each indoor outlet SH (a, b, c) defined by equation (2) and each indoor outlet SH tolerance (a, b, c) defined by equation (3) are calculated. In step 106a, it is determined whether each indoor outlet SH tolerance (a, b, c) is within the target range. If it is not within the target range, the opening of the electronic expansion valves 4a to 4c other than the minimum value is corrected in step 107a according to FIG. 13 (c). If it is within the target range, it is determined at step 108 whether the intake SH and the discharge temperature are within the target values. If they are within the target values, the openings of the electronic expansion valves 4a-4c are fixed at step 109. If the target value is not reached, the process returns to step 102, and the above process is repeated until all of the suction SH, the discharge temperature, and the indoor outlet SH tolerances reach the target value.

  This is because the control is performed so that the outlet SH of the other indoor units is brought close to this with the minimum value of the indoor outlet SH as a reference value. The minimum value of the indoor outlet SH is the degree of superheat of the intake temperature of the compressor 1 (intake SH). Therefore, if the tolerance with the minimum value falls within the target range, each indoor outlet SH becomes an appropriate value, and the temperature distribution of each indoor heat exchanger There is no unevenness, and it is possible to prevent dew jumping and capacity reduction.

Embodiment 8 FIG.
In Embodiment 7, the indoor outlet SH tolerance is used to correct the electronic expansion valves 4a to 4c, but a gas pipe temperature tolerance may be used instead of the indoor outlet SH tolerance.
The refrigerant circuit diagram is the same as FIG.
The gas pipe temperature tolerance used to explain the contents of the control is defined by equation (4).

  The contents of the valve opening degree control will be described based on the flowchart of FIG. Except for steps 106b and 107b, it is exactly the same as the flowchart of FIG. 11. In step 106b, it is determined whether each gas pipe temperature (a, b, c) defined by equation (4) is within the target range. If it is not within the range, the opening of the electronic expansion valves (4a, 4b, 4c) except for the minimum value is corrected in step 107b according to FIG. 13 (d). If each gas pipe temperature (a, b, c) is not within the target range, go to step 8. Since other processes are the same as those in FIG.

  The basic effect of this embodiment using the gas pipe temperature tolerance instead of the indoor outlet SH tolerance, that is, the temperature distribution of the indoor heat exchanger is made uniform to prevent exposure and decrease in capacity. Although it is the same as the seventh embodiment, in the eighth embodiment, since the gas pipe temperature tolerance is used instead of the indoor outlet SH, the detected temperature of the gas pipe temperature sensors (16a to 16c) and the detected temperature of the evaporation temperature sensor 15 are compared. There is no need to perform the calculation, and the calculation process is simplified.

1 is a refrigerant circuit diagram of a multi-room air conditioner according to Embodiment 1 of the present invention. It is a control block diagram of the multi-room air conditioner according to Embodiment 1 of the present invention. It is a flowchart figure which shows the control content of the multi-room air conditioner by Embodiment 1 of this invention. It is a flowchart figure which shows the control content of the multi-room air conditioner by Embodiment 2 of this invention. It is a flowchart figure which shows the control content of the multi-room air conditioner by Embodiment 3 of this invention. It is a refrigerant circuit diagram of the multi-room air conditioner by Embodiment 4 of this invention. It is a flowchart figure which shows the control content of the multi-room air conditioner by Embodiment 4 of this invention. It is a flowchart figure which shows the control content of the multi-room air conditioner by Embodiment 5 of this invention. It is a flowchart figure which shows the control content of the multi-room air conditioner by Embodiment 6 of this invention. It is a refrigerant circuit diagram of the multi-room air conditioner by Embodiment 7 of this invention. It is a flowchart figure which shows the control content of the multi-room air conditioner by Embodiment 7 of this invention. It is a flowchart figure which shows the control content of the multi-room air conditioner by Embodiment 8 of this invention. It is a figure which shows the specific operation | movement of the control of the multi-room air conditioner by Embodiment 7 and 8 of this invention. It is a refrigerant circuit figure of the conventional multi-chamber type air conditioner (conventional example 1). It is a refrigerant circuit figure of the conventional multi-chamber type air conditioner (conventional example 2).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Outdoor heat exchanger, 4a-4c Electronic expansion valve, 5a-5c Indoor heat exchanger, 6 Accumulator, 9 Solenoid valve, 11 Electronic expansion valve for evaporating temperature generation, 14 Inhalation temperature sensor, 15 Evaporation temperature sensor, 16a-16c Gas pipe temperature sensor, 21 Discharge temperature sensor.

Claims (4)

  A compressor, a four-way valve, an outdoor heat exchanger, an accumulator, and an evaporating temperature generation circuit are connected in sequence to form a refrigerant circuit including a double-pipe heat exchanger. In a multi-room air conditioner having an electronic expansion valve and an indoor unit to which an indoor heat exchanger is connected between the branch pipes, suction temperature detection means for detecting the suction temperature of the compressor, and the evaporation temperature generation circuit Evaporation temperature detection means for detecting the evaporation temperature, gas pipe temperature detection means for detecting the temperature of each indoor heat exchanger outlet gas pipe, and suction of the compressor based on output values of the suction temperature detection means and the evaporation temperature detection means Inhalation SH calculating means for calculating SH (superheat degree), and gas for determining the minimum of the gas pipe temperatures detected by the gas pipe temperature detecting means and calculating the difference between the minimum value and each gas pipe temperature Tube temperature tolerance calculation An electronic expansion valve opening for calculating and controlling the correction opening of the electronic expansion valve so that the values calculated by the means, the intake SH calculating means, and the gas pipe temperature tolerance calculating means fall within a target value range. A multi-room air conditioner comprising a control means.   Discharge temperature detection means for detecting the discharge temperature of the compressor is provided, and the electronic expansion valve opening degree control means opens the electronic expansion valve so that the value calculated by the discharge temperature detection means also falls within the target value range. The multi-room air conditioner according to claim 1, wherein the degree is calculated and controlled.   A compressor, a four-way valve, an outdoor heat exchanger, an accumulator, and an evaporating temperature generation circuit are connected in sequence to form a refrigerant circuit including a double-pipe heat exchanger. In a multi-room air conditioner having an electronic expansion valve and an indoor unit to which an indoor heat exchanger is connected between the branch pipes, suction temperature detection means for detecting the suction temperature of the compressor, and the evaporation temperature generation circuit Evaporation temperature detection means for detecting the evaporation temperature, gas pipe temperature detection means for detecting the temperature of each indoor heat exchanger outlet gas pipe, and suction of the compressor based on output values of the suction temperature detection means and the evaporation temperature detection means Inhalation SH calculating means for calculating SH, indoor outlet SH calculating means for calculating each indoor outlet SH from output values of the gas pipe temperature detecting means and the evaporation temperature detecting means, and this indoor outlet SH calculating means Calculated by the indoor outlet SH tolerance calculating means for determining the smallest one of the indoor outlets SH and calculating the difference between the minimum value and each indoor outlet SH, and the intake SH calculating means and the indoor outlet SH tolerance calculating means. And an electronic expansion valve opening control means for calculating and controlling the corrected opening of the electronic expansion valve so that the measured value falls within the range of the target value.   Discharge temperature detection means for detecting the discharge temperature of the compressor is provided, and the electronic expansion valve opening degree control means opens the electronic expansion valve so that the value calculated by the discharge temperature detection means also falls within the target value range. The multi-room air conditioner according to claim 3, wherein the degree is calculated and controlled.

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