JP3338229B2 - Operating method of air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating an air conditioner.

[0002]

2. Description of the Related Art As shown in FIG.
In a refrigeration apparatus or an air conditioner in which a condenser 83, a decompressor 85, and a 92 evaporator 87 are sequentially connected to form a refrigerant circuit,
A technique for varying the capacity of a compressor according to a load is known.

[0003] In the prior art, there is an air conditioner using a so-called inverter compressor 91 that changes the frequency of electric power used as a refrigerant control device to change its capacity.

[0004]

However, in the above-mentioned prior art, when an inverter compressor is used as the compressor, the amount of refrigerant (refrigeration capacity) discharged from the compressor is continuously and finely controlled over a wide range. It can be operated but is expensive, and when an inverter compressor is used, the frequency component of the electric power gives noise to a nearby computer or the like, or adversely affects the puncturing of a capacitor (electric component). There is a point.

On the other hand, multistage control is performed by the rated compressor using only the refrigerant return mechanism that returns a part of the refrigerant discharged from the rated compressor to the suction side without using the inverter compressor. However, in this case, since smooth control cannot be performed, hunting is caused and the control range is limited to a very narrow range. When such hunting occurs, there is a problem that the fluctuation of the room temperature becomes large and a comfortable air-conditioning state cannot be obtained.

[0006] Further, there is a demand for simplification of the structure and reduction of the number of parts in the air conditioner.

It is an object of the present invention to provide a method of operating an air conditioner that does not adversely affect the surroundings and can prevent hunting.

[0008]

SUMMARY OF THE INVENTION The present invention comprises a refrigerating apparatus comprising a plurality of indoor units having an indoor heat exchanger and an outdoor unit having an outdoor heat exchanger and a plurality of compressors. In the method of operating an air conditioner, which controls the capacity of the compressor, each indoor heat exchanger includes a control valve that controls a flow rate of refrigerant, and the compressor has a constant frequency of electric power used for driving the compressor. Only the rated compressor is provided, and at least one of the rated compressors has a power saving mechanism for returning a part of the refrigerant being compressed in the container of the rated compressor to the container of the compressor, and is discharged from each rated compressor. A refrigerant return mechanism for returning a part of the cooled refrigerant to the refrigerant suction side of each rated compressor. And controlling the opening of the valve of the control valve for, and is characterized in that the stepwise control capability by the refrigerant return mechanism and the power save mechanism only if it can not addressed by the control valve.

[0009]

According to the present invention, the refrigeration capacity is made variable only by the rated compressor. In this case, a part of the refrigerant in the middle of the compression in the compressor container is returned to the compressor container by the power saving mechanism, and the refrigerant is returned. A part of the refrigerant discharged from the compressor is returned to the suction side of the compressor by a mechanism. As described above, by controlling the refrigerating capacity by combining the two mechanisms of the power saving mechanism and the refrigerant return mechanism, even if only the rated compressor is used,
Since fine control can be performed over a wide range, hunting can be prevented, and control similar to that of an inverter compressor can be performed. In addition, since an inverter compressor that changes the frequency of supplied power is not used, there is no adverse effect on the surroundings.

Moreover, by using the present invention, an inverter (frequency converter) is not required unlike a conventional inverter compressor, and the amount of circulating refrigerant in the refrigeration system is adjusted by a control valve in an indoor unit. Therefore, the outdoor unit does not need a valve for controlling such a refrigerant circulation amount. Therefore, the outdoor unit does not require a liquid receiver (receiver) or the above-described control valve, which is conventionally used, so that the configuration is simplified and the number of components can be reduced.

In addition, since the amount of refrigerant flowing into the indoor heat exchanger is adjusted by the control valve of the indoor unit before the power saving mechanism (capacity control) operates, the refrigeration system can be operated according to the load. Stable and comfortable air conditioning becomes possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, this is an air conditioner of a separation type according to an embodiment of the present invention. The air conditioner 1 has a plurality of indoor units A1, A2, an outdoor unit B, and both units A1, A2, A2. And B between the units B. Each of the indoor units A1 and A2 has a built-in indoor heat exchanger 3 which functions as an evaporator during cooling operation and functions as a condenser during heating operation, and an indoor fan (not shown).

Each of the indoor units A1 and A2 has a temperature detector T1 and a temperature detector T1 on the inlet side and the outlet side of the indoor heat exchanger 3, respectively.
T2 is provided, and each detection signal is sent to the control device 5a, and the load on each indoor heat exchanger 3 is measured. In each of the indoor units A1 and A2, a control valve (mechanical valve) 17 is provided in the indoor heat exchanger 3. The control valve 17 is connected to each of the indoor units A1, A
In addition to shutting down when the operation of 2 stops, stopping the inflow of refrigerant,
By adjusting the opening of the valve, the amount of refrigerant flowing in accordance with the load is controlled.

The outdoor unit B is provided with a refrigerant control device 5 including a compressor (described later) and the like.
The capacity of the compressor and the like is controlled in response to a control signal from the control device 5a. The outdoor unit B further includes a four-way valve 6, an outdoor heat exchanger 7 that functions as a condenser during the cooling operation and an evaporator during the heating operation, and an accumulator 8.
And built-in.

In the present embodiment, the pipe diameter of the indoor heat exchanger 3 and the outdoor heat exchanger 7 of the outdoor unit B is about 7 mm smaller than that of a normal pipe (about 9 mm). Inexpensive and small in capacity. Such a small pipe diameter is used. As a result, the capacity of the refrigerant circuit on the indoor units A1 and A2 side can be reduced, and the amount of the refrigerant to be charged can be reduced.

In the overall refrigerant circuit of the air conditioner 1, a so-called depressurizer is only the control valve 17 of the indoor units A1 and A2, and a conventionally required receiver tank (see FIG. 8) and the like. Is not located.

The refrigerant control device 5 is provided with two compressors 11 and 12, each of which has an accumulator 8 connected to its suction side and an oil separator 9 connected to its discharge side. In this embodiment, one compressor 11 has 4 horsepower, and the other compressor 12 has 6 horsepower.
Uses horsepower.

The two compressors 11 and 12 are so-called rated compressors in which the frequency of power consumption is constant. One of the compressors (compressor with smaller horsepower) 11 includes a power saving mechanism 13 described later. The output is saved and the discharge amount is made variable. Further, the control device 5 is provided with a refrigerant return mechanism 15 for returning a part of the refrigerant from the discharge pipes discharged from both the compressors 11 and 12 to the suction pipe 45 on the refrigerant suction side of the compressor.

As shown in FIGS. 2 and 3, the power saving mechanism 13 includes a rotary compression element housed in a closed container 18 of the compressor 11, and the rotary compression element includes an intermediate partition plate 27 and an intermediate partition plate 27. 27 is provided with a pair of cylinders 21 and 22 respectively provided on both sides. First holes 23, 24 provided in the inner side walls of both cylinders 21, 22
And second holes 25, 26 provided in both cylinders 21, 22 so as to communicate with the first holes 23, 24;
A third hole 28 provided in an intermediate partition wall 27 communicating the holes 25 and 26 is formed. In addition, both cylinders 21,
Pistons 29 and 30 are housed in the second holes 25 and 26 of the coil 22. A coil spring (which may be a leaf spring or a bellows if it is an elastic body) extends across the pistons 29 and 30.
Are arranged. The recesses 31 formed in the cylinders 21 and 22 make the second holes 2 of the cylinders 21 and 22 respectively.
The fourth holes 33 and 34 communicating with the fifth holes 26 and the fourth holes 3
A passage 35 is formed for selectively communicating between 3, 3 and the low pressure side or high pressure side of the external refrigerant circuit with a switching valve or the like.

Then, the power saving mechanism 1 having the above-described configuration is used.
3 controls the passage 35, the fourth holes 33 and 34, the recess 3
By applying the low pressure side pressure as back pressure to the second holes 25, 26 via 1, the pistons 29, 30 are moved to the top dead center, and the first holes 23, 24 are opened as shown in FIG. This allows the gas in the compression process in one cylinder 21 to pass through the first hole 23, the second hole 25, the third hole 28, and the second hole 2.
6, while flowing through the first hole 24 into the other cylinder 22 in the suction process, during normal operation, as shown in FIG. 3, through the passage 35, the fourth holes 35 and 34, and the recess 31. Then, by applying the high pressure side pressure to the second holes 25, 26 as a back pressure chamber, the pistons 29, 30 are moved to the bottom dead center, and both the first holes 23, 24 are closed. Eliminate gas transfer between the 22.

According to the power saving mechanism 13 of the present embodiment, about 50% of the output can be saved, and the output of 2 hp can be saved for a 4 hp compressor. ON / OFF of this power save mechanism 13
Is performed by opening and closing the valve 41 (see FIG. 1) in response to a command from the control device 5a.

[0023] The refrigerant return mechanism 15 is connected to the discharge side pipes of both rated compressors 11 and 12 to connect the two compressors 1 and 1 to each other.
A part of the discharged refrigerant is returned to the suction side pipes 1 and 12, and in this embodiment, the discharge pipe 43 between the oil separator 9 and the four-way valve 6 is connected to the suction pipe between the accumulator 8 and the four-way valve 6. A return pipe 47 communicating with the pipe 45 is provided, and a part of the discharged refrigerant is returned to the accumulator 8 by opening and closing a return valve 49 provided in the return pipe. Note that the refrigerant return mechanism 15 of this embodiment saves one horsepower output.

The return valve 49 is opened / closed in response to a control signal from the control device 5a, and the indoor units A1, A2
To control the amount of refrigerant (pumping output) supplied to the pump.

Next, the operation of this embodiment will be described.

In the refrigerant circuit of the air conditioner shown in FIG. 1, when the four-way valve 6 is switched to change the flow of the refrigerant, a cooling operation or a heating operation is performed. In FIG. 1, the flow of the refrigerant during cooling is indicated by a solid line, and the flow of the refrigerant during heating is indicated by a broken line.

During operation, the temperature sensors T1 and T2 of each indoor unit detect the refrigerant inlet and outlet temperatures of the indoor heat exchanger 3, respectively, and transmit the detection signals to the control unit 5.
Send to a. The control device 5a calculates an air-conditioning load required for each indoor heat exchanger 3 based on, for example, a set temperature signal from the remote controller 52 and temperature signals from the temperature sensors T1 and T2. Indoor units A1, A
Adjusting the opening of the control valve 17 of the second or the refrigerant control device 5
To control the refrigerant.

Next, the refrigerant control method will be described. As shown in FIG. 5, the control device 5a first controls the opening of the control valve (mechanical valve) 17 based on the load detected in step S1. Next, in step S2, it is determined whether the load is within a certain range. In other words, it is determined whether or not the difference | T0−T3 | between the room temperature T0 and the set temperature (the temperature set by the user using the remote controller 52) T3 is smaller than the predetermined value F. | T0-T3 |
Is smaller than the predetermined value F, the process returns to step S1, and
When | T0−T3 | is larger than the predetermined value F, the process proceeds to step S3, and the capacity control by the refrigerant control device 5 is performed.

That is, in this embodiment, first, the valve opening of the control valve 17 is controlled. If the control of the control valve 17 alone cannot control the air conditioning (refrigeration) capacity, the refrigerant control device 5 This is to control the ability.

Here, the control method by the control valve 17 will be described in more detail with reference to FIG. In step S11, the initial load | T required for the indoor heat exchanger is first detected by detecting the temperature based on the room temperature T0 and the set temperature T3.
0−T3 | is detected, and the process proceeds to step S12.

In step S12, the valve opening of the control valve 17 is set in response to the initial load detected in step S11, and the process proceeds to step S13.

In step S13, a calculation is performed based on the inlet and outlet temperatures T1 and T2 of the heat exchanger 3, and | T1-T2
| = ΔT is detected, and the process proceeds to step S14.

In step S14, it is determined whether or not ΔT is equal to a predetermined value K.
The process returns to step S15 if the values are not equal.

In step S15, it is determined whether or not ΔT is larger than a predetermined value K. If ΔT is larger, step S1 is performed.
6, the control valve 17 is opened, and the process proceeds to step S17. After the refrigerant control device 5 controls the capacity of the compressor, the process returns to step S13. On the other hand, ΔT is a predetermined value K
If it is not larger, the process proceeds to step S18, where the control valve 17 is closed by a predetermined amount to control the opening degree to be smaller, and then returns to step S13.

Next, the control of the capacity of the compressor by the refrigerant control device 5 in step S17 will be described.

In the refrigerant control device 5, as shown in FIG. 4, the refrigerant pumping output is variously controlled by the power save mechanism 13 and the refrigerant return mechanism 15 for each horsepower.

That is, the two rated compressors 11 and 12
Output is 4 hp and 6 hp, so power save mechanism 1
In a state where the third valve 41 and the return valve 49 are turned off (a state where the two valves are closed), a discharge output of 10 horsepower can be obtained. When the required output (horsepower) is 10 hp, only the magnet switches of the two rated compressors 11 and 12 are turned on. Here, the inside of the rated compressor 11 is in the state of FIG.

When the required horsepower is 9 horsepower, the respective magnet switches of the two rated compressors 11 and 12 are turned on, and the return valve 49 is opened (ON).
In this case, the discharge amount for one horsepower is returned to the accumulator 8 from the return pipe 47.

When the required horsepower is 8 hp, the magnet switches of the two rated compressors 11 and 12 are turned on, the return valve 49 is kept closed (-), and the valve 41 of the power save mechanism 13 is turned off. Open (O
N). In this case, as shown in FIG. 2, due to the action of the power saving mechanism 13, the output discharged from one compressor 11 becomes 2 horsepower (the output of 4 horsepower is halved), and the output of the other compressor 12 becomes Since it is six horsepower, the total is eight horsepower.

When the required horsepower is 7 hp, the respective magnet switches of the two rated compressors 11 and 12 are turned ON, and the return valve 49 is opened (ON);
The valve 41 of the power save mechanism 13 is opened (ON). In this case, due to the action of the power saving mechanism 13, the output discharged from the one compressor 11 becomes 2 horsepower (the output of 4 horsepower is halved) (see FIG. 2), and further 1 horsepower from the return pipe 47. Minutes of refrigerant is returned, for a total of 7 horsepower.

Similarly, as shown in the table of FIG. 4, by combining the opening and closing (ON or-) of the valve 41 of the power saving mechanism 13 and the return valve 49, it is possible to finely determine the horsepower by 1 to 10 hp by 1 hp. Control becomes possible.

By controlling the operating horsepower in this way, a required variable output can be obtained only with a rated compressor without using an inverter compressor. Therefore, an adverse effect such as noise due to the inverter compressor can be prevented, and an inexpensive device can be provided.

Further, since the control of the compressor capacity in step S17 according to the present embodiment is performed after the control by the control valve 17, smooth control can be performed as shown by the dashed line in the graph of FIG.

Further, in this embodiment, the pipe diameter of the indoor heat exchanger is 7 mm, which is smaller than the pipe diameter of the outdoor heat exchanger of 9 mm. A control valve 17 acting as a refrigerant decompressor is disposed only in the indoor units A1 and A2 so that the refrigerant flowing in the piping between the units becomes liquid during both the cooling and heating operations. With these two configurations, the amount of refrigerant sealed in the refrigerant circuit can be minimized, and the receiver tank and the on-off valve 92 (see FIG. 8)
Becomes unnecessary.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

For example, as shown in FIG. 7, the refrigerant control device 5 may have a configuration in which the compressor has only the power save mechanism 13. Output control in this case is, for example,
It is controlled every two horsepower.

The indoor unit A is not limited to a multi-type air conditioner having a plurality of indoor units, and the same effect can be obtained even with a single indoor unit A.

[0048]

According to the present invention, since the refrigerant control device having the compressor includes the power save mechanism and the refrigerant return mechanism, the two mechanisms of the power save mechanism and the refrigerant liquid return mechanism are combined to control the refrigerant. By controlling the pumping output, even if only the rated compressor is used, fine control can be performed in a wide range, so that hunting can be prevented, the same control as the inverter compressor can be performed, and the frequency of the supplied power changes Since no inverter compressor is used, there is no adverse effect on the surroundings.

Also, since the amount of refrigerant supplied to the indoor unit can be controlled by the capacity of the compressor and the control valve in the indoor unit, other equipment for controlling the amount of refrigerant in the outdoor unit does not require a receiver tank or the like. The configuration is simplified, and the number of parts can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a power save mechanism built in the compressor.

FIG. 3 is a cross-sectional view illustrating the operation of the power save mechanism shown in FIG.

FIG. 4 is a diagram showing a relationship between a change in operating horsepower in a refrigerant control device and an operation of a compressor.

FIG. 5 is a flowchart showing a schematic control of the air conditioner according to the embodiment.

FIG. 6 is a flowchart showing the control contents shown in FIG. 5 in more detail.

FIG. 7 is a circuit diagram of an air conditioner according to another embodiment.

FIG. 8 is a circuit diagram of a conventional air conditioner.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 air conditioner 2 unit piping 3 indoor heat exchanger 5 refrigerant control device 11 rated compressor 12 rated compressor 13 power save mechanism 15 refrigerant return mechanism 17 on-off valve

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-297784 (JP, A) JP-A-3-79946 (JP, A) JP-A-4-369350 (JP, A) 5567 (JP, Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 1/00

Claims (1)

(57) [Claims] 1. A refrigeration system comprising a plurality of indoor units having an indoor heat exchanger and an outdoor unit having an outdoor heat exchanger and a plurality of compressors, and controls the capacity of the compressors according to the air conditioning load. In the operation method of the air conditioner, each indoor heat exchanger includes a control valve that controls an inflow amount of the refrigerant, and the compressor includes only a rated compressor in which a frequency of electric power used for driving the indoor heat exchanger is constant. At least one of the rated compressors has a power saving mechanism for returning a part of the refrigerant in the course of compression in the container of the rated compressor to the container of the compressor, and a part of the refrigerant discharged from each rated compressor. A refrigerant return mechanism for returning the refrigerant to the refrigerant suction side of the rated compressor; A method of operating an air conditioner, comprising controlling the temperature and controlling the capacity stepwise by the refrigerant return mechanism and the power save mechanism only when the control valve cannot cope with the degree.