JPH1047797A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a freezing cycle that is stable and has a good response against pressure variations and ensure reliability of a compressor at all times by detecting pressure on a discharge side of the compressor, and controlling opening/closing of a sealing valve provided between a branch point of a plurality of outdoor side heat exchangers and the outdoor side heat exchangers with the aid of the detected pressure. SOLUTION: A freezing cycle is constructed with discharged pressure detection means 4 from a compressor 2, a first outdoor heat exchanger 13, a second outdoor heat exchanger 14 provided parallely to the first outdoor heat exchanger 13, a sealing valve 15 provided on the side of a four-way valve of the first outdoor heat exchanger 13, and sealing valve control means 18, etc. Herein, upon cooling operation for example discharge pressure detected by discharge pressure detection means 4 is compared with previously determined control conditions (for example, closing operation if the discharge pressure < 0.9MPa, and closing operation if a compression ratio < 3.0, and closing operation if the compression ratio < 3.0, and if indoor load < 20 deg.C, and if outdoor load < 20 deg.C)) to determine opening/closing of the sealing valve 15 for control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner and, more particularly, to a low-temperature outdoor air conditioner.

[0002]

2. Description of the Related Art Conventionally, as this kind of multi-room type air conditioner, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 8-5184.

Hereinafter, a conventional multi-room air conditioner will be described with reference to FIG. FIG. 10 shows a refrigeration cycle diagram of a conventional multi-room air conditioner. In FIG. 10, reference numeral 1 denotes an outdoor unit of a multi-room air conditioner,
It comprises a four-way valve 3, an outdoor heat exchanger 11, and an outdoor expansion valve 12. Numeral 8 denotes an indoor unit, which comprises an indoor expansion valve 9 and an indoor heat exchanger 10, respectively.
The pipes are connected in parallel by a gas pipe 7. Reference numeral 4 denotes discharge pressure detecting means provided on the high pressure side of the compressor 2;
Is an outdoor electric expansion valve controller for controlling the outdoor expansion valve 12.

The operation of the multi-room air conditioner configured as described above will be described below.

[0005] First, the cooling operation will be described. In this case, the flow of the refrigerant is indicated by a solid line arrow, and each indoor expansion valve has an opening corresponding to each indoor load.

The refrigerant discharged from the compressor 2 is supplied to the four-way valve 3
The refrigerant which flows into the outdoor heat exchanger 11 through the, and is condensed and liquefied in the outdoor heat exchanger 11 is guided to the liquid pipe 6 through the outdoor expansion valve 12. Then, the pressure is reduced by the indoor expansion valve 9, flows into each indoor heat exchanger 10, evaporates and then passes through the gas pipe 7, through the four-way valve 3, and through the compressor 2.
And perform the cooling operation.

Next, control of the outdoor expansion valve 12 will be described. The outdoor expansion valve controller 5 inputs the discharge pressure detected by the discharge pressure sensor 4, determines the opening degree of the outdoor expansion valve 12 by calculating the discharge pressure target value, and controls the outdoor expansion valve. ing.

For example, when the load on the outdoor side increases due to an increase in the outdoor air temperature or the like, the opening degree of the outdoor expansion valve 12 is increased because the discharge pressure increases to a target value or more. Conversely, when the load on the outdoor side is reduced due to a decrease in the outdoor temperature, the opening degree of the outdoor expansion valve 12 is reduced because the discharge pressure decreases to a target value or less.

[0009]

However, in the above-mentioned conventional configuration, the capacity variable width is small because the condensing capacity is controlled by changing the liquid refrigerant amount in the heat exchanger, and the cooling operation at a low outside unit temperature is required. However, there has been a problem that the compressor is not sufficiently reliable because the condensing capacity is excessive, the discharge pressure is abnormally reduced, and the compression ratio is excessively low.

[0010] The present invention solves the above-mentioned problems, and forms a stable refrigeration cycle with good response to pressure fluctuations such as when the discharge pressure drops sharply, and always ensures the reliability of the compressor. It is another object of the present invention to provide an air conditioner that can realize a cooling operation corresponding to a wide range of loads with inexpensive specifications.

Another object of the present invention is to secure an appropriate compression ratio with good response when the compression ratio becomes excessively small and to prevent poor oiling of the compressor beforehand, thereby ensuring higher reliability. It is.

Further, when the compression ratio changes excessively,
It is an object of the present invention to prevent a malfunction of a sealing valve and always form an efficient and stable refrigeration cycle.

[0013]

In the air conditioner according to the present invention, a branch point of the plurality of outdoor heat exchangers between the compressor and the plurality of outdoor heat exchangers and a branch point of the outdoor heat exchanger are provided. A sealing valve between the compressor, a discharge pressure detecting means for detecting the pressure on the discharge side of the compressor, a sealing valve control means for controlling the opening and closing of the sealing valve with a detection value of the discharge pressure detecting means as an input It is provided with.

According to the present invention, a stable refrigeration cycle with good response to pressure fluctuations is formed, the reliability of the compressor is always ensured, and the cooling operation corresponding to a wide range of loads with low-cost specifications is realized. An air conditioner that can be operated is obtained.

Further, there are provided suction pressure detecting means for detecting the pressure on the suction side of the compressor, and sealing valve control means for controlling the opening and closing of the sealing valve by using a detection value of the suction pressure detecting means as an input. It is a thing.

According to the present invention, an appropriate compression ratio is ensured with good response, and poor refueling of the compressor is prevented beforehand.
An air conditioner that can ensure higher reliability can be obtained.

Further, suction pressure detecting means for detecting the pressure on the suction side of the compressor, indoor load detecting means for detecting the load on the indoor unit, outdoor load detecting means for detecting the load on the outdoor unit, and the suction pressure A sealing valve control unit that controls opening and closing of the sealing valve by inputting a detection value of a detection unit, a detection value of the indoor load detection unit, and a detection value of the outdoor load detection unit.

According to the present invention, it is possible to obtain an air conditioner capable of preventing a malfunction of the sealing valve due to an excessive decrease in the compression ratio and always forming an efficient and stable refrigeration cycle.

[0019]

DETAILED DESCRIPTION OF THE INVENTION The invention as set forth in claim 1 of the present invention comprises a compressor, a plurality of outdoor heat exchangers, an outdoor expansion valve, and the plurality of outdoor heat exchangers between the compressor and the outdoor heat exchanger. An outdoor unit having a sealing valve between a branch point of the outdoor heat exchanger and the outdoor heat exchanger, a discharge pressure detecting means for detecting a pressure on a discharge side of the compressor, and the discharge pressure detecting means And a sealing valve control means for controlling the opening and closing of the sealing valve by using the detected value as an input, and grasping the necessary condensation capacity by detecting the pressure on the discharge side of the compressor. By opening and closing the sealing valve against pressure fluctuations, a stable refrigeration cycle with good response is formed, the reliability of the compressor is always ensured, and the cooling operation corresponding to a wide range of loads is realized. It has the action of:

According to a second aspect of the present invention, in addition to the first aspect, a suction pressure detecting means for detecting a pressure on the suction side of the compressor, a detection value of the discharge pressure detecting means, and the suction pressure detection With the detection value of the means as input, it is provided with sealing valve control means for controlling the opening and closing of the sealing valve, by detecting the pressure on the discharge side and the pressure on the suction side of the compressor,
By ensuring an appropriate compression ratio with good response and preventing defective oiling of the compressor beforehand, it has the effect of ensuring higher reliability.

According to a third aspect of the present invention, in addition to the first aspect, a suction pressure detecting means for detecting a pressure on a suction side of the compressor and an indoor load detecting means for detecting a load of the indoor unit. And an outdoor load detecting means for detecting a load on the outdoor unit,
Sealing for controlling the opening and closing of the sealing valve by inputting a detection value of a discharge pressure detection unit, a detection value of the suction pressure detection unit, a detection value of the indoor load detection unit, and a detection value of the outdoor load detection unit. Valve control means for preventing malfunction of the sealing valve due to an excessive decrease in compression ratio, and has an effect that an efficient and stable refrigeration cycle can always be formed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. The same components as those of the conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted.

(Embodiment 1) FIG. 1 shows a refrigeration cycle diagram. In FIG. 1, reference numeral 4 denotes a discharge pressure detecting means for detecting a discharge pressure of the compressor 2, 13 denotes a first outdoor heat exchanger,
14 is a second outdoor heat exchanger provided in parallel with the first outdoor heat exchanger 13, and 15 is the first outdoor heat exchanger 13
A sealing valve 18 provided in series on the side of the four-way valve 3 is a sealing valve control means for controlling the opening and closing of the sealing valve 15 according to the output of the discharge pressure detecting means 4. The discharge pressure detecting means 4 is preferably a pressure sensor, and the sealing valve 15 has a function of sealing the flow of the refrigerant, and is preferably constituted by an electromagnetic valve or a reversible valve.

The operation of the air conditioner configured as described above will be described. First, the cooling operation will be described. The flow of the refrigerant in this case is indicated by a solid line arrow, and each indoor expansion valve 9 has an opening corresponding to each indoor load.

The refrigerant discharged from the compressor 2 is supplied to the four-way valve 3
The refrigerant is divided into the first outdoor heat exchanger 13 and the second outdoor heat exchanger 14 and flows therethrough, and the condensed and liquefied refrigerant joins at the entrance of the outdoor expansion valve 12 and passes through the outdoor expansion valve 12. To the liquid pipe 11. Then, the pressure is reduced by the indoor expansion valve 9,
After flowing into each indoor side heat exchanger 10 and evaporating and evaporating respectively, it returns to the compressor 2 through the gas pipe 7 via the four-way valve 3 to perform the cooling operation.

FIG. 2 is a control block diagram of the sealing valve 15, and FIG.

Next, control of the sealing valve 15 during the cooling operation will be described with reference to FIG. First, the cooling or heating operation is selected (step 1). During the cooling operation, the discharge pressure detected by the discharge pressure detecting means 4 (step 2).
Is compared with a previously determined control condition such as condition 1 (step 3), and the opening and closing of the sealing valve 15 is determined and controlled (step 4).

(Condition 1) Close operation if discharge pressure is <0.98 MPa. For example, in the case of a cooling operation in which the outside air temperature is low or a cooling load in which the number of indoor units operated is small, the condensing capacity becomes excessive, so that the discharging operation is performed. The pressure drops abnormally, for example, to 0.75 MPa. In such a case, the sealing valve 15 is closed, the refrigerant is prevented from flowing into the first outdoor heat exchanger 13, the condensation capacity can be instantaneously reduced, and the discharge pressure rises responsively. That is, for example, the first and second outdoor heat exchangers 13 and 14 have the same capacity, and the outdoor expansion valve 12
When the control of the condensing capacity from 100% to 100% is possible, the control range of the condensing capacity is 25% by closing the sealing valve 15.
From 100% to 100%, and the pressure state can always be kept stable regardless of the magnitude of the load.
Reliability can be ensured.

(Embodiment 2) FIG. 4 shows a refrigeration cycle diagram, and the same components as those in Embodiment 1 are denoted by the same reference numerals and detailed description thereof will be omitted. 21 is a sealing valve control means, 20
Is a suction pressure detecting means for detecting the suction pressure of the compressor 2, and the suction pressure detecting means 20 is preferably a pressure sensor.

The operation of the air conditioner configured as described above is the same as that of the first embodiment, and therefore the description is omitted here and only the control will be described.

FIG. 5 is a control block diagram of the sealing valve 15, and FIG.
Is a control flowchart of the sealing valve 15.

Next, control of the sealing valve 15 during the cooling operation will be described with reference to FIG. First, a cooling or heating operation is selected (step 11). During the cooling operation, the compression ratio is determined from the discharge pressure detected by the discharge pressure detecting means 4 and the suction pressure detected by the suction pressure detecting means 20 (step 12). Is calculated (step 13), and the compression ratio is compared with a predetermined control condition such as condition 2 (step 14), and the opening and closing of the sealing valve 15 is determined and controlled (step 15). ).

(Condition 2) Close operation if the compression ratio is less than 3.0 For example, in the case of a cooling operation in which the outside air temperature is low or a cooling load in which the number of indoor units is small, the condensing capacity becomes excessive, so that the compression ratio Is abnormally reduced, for example, to 2.0.
In such a case, the sealing valve 15 is closed, the refrigerant is prevented from flowing into the first outdoor heat exchanger 13, the condensing capacity can be instantaneously reduced, and the compression ratio increases responsively.

That is, since the compression ratio is constantly monitored, an abnormal decrease in the compression ratio can be prevented from occurring, the higher reliability of the compressor 2 can be always secured, and a stable refrigeration cycle can be realized. .

It should be noted that the present invention can be similarly implemented by using a pressure difference between the discharge pressure and the suction pressure. (Embodiment 3) FIG. 7 shows a refrigeration cycle, and the same components as those in Embodiment 1 are denoted by the same reference numerals and detailed description thereof will be omitted. 23 is an indoor load detecting means, 24 is an outdoor load detecting means, 25 is a sealing valve control means, and the indoor load detecting means 23 can use the indoor unit operating capacity in a thermistor or a multi-room air conditioner. The outdoor load detecting means 24 is preferably a thermistor.

The operation of the air conditioner configured as described above is the same as that of the first embodiment, and therefore the description is omitted here and only the control will be described.

FIG. 8 is a control block diagram of the sealing valve 15, and FIG. 9 is a control flowchart of the sealing valve 15. Next, control of the sealing valve 15 during the cooling operation will be described with reference to FIG. First, the cooling or heating operation is selected (step 21). During the cooling operation, on the one hand, the discharge pressure detected by the discharge pressure detecting means 4 and the suction pressure detected by the suction pressure detecting means 20 (step 22) are used. The compression ratio is calculated (step 23). On the other hand, the indoor load is detected by the indoor load detecting means 23, and the outdoor load detecting means 2 is detected.
4 detects an outdoor load (step 24). Next, the compression ratio, the indoor load, and the outdoor load are compared with control conditions determined in advance, for example, as condition 3 (step 25), and the opening and closing of the sealing valve 15 are determined and controlled.
(Step 26) (Condition 3) Closing operation if the compression ratio is <3.0, the indoor load is less than 20 ° C., and the outdoor load is less than 20 ° C. For example, when the compressor 2 is started or when there is a sudden change in the indoor load. May temporarily reduce the compression ratio of the compressor 2, but in such a case, the outside air temperature, the indoor temperature,
By constantly monitoring the operating capacity of the indoor unit, it is possible to prevent an erroneous operation in which the sealing valve closes due to an excessive decrease in the compression ratio and the discharge pressure rises abnormally.

That is, the necessity of the sealing valve 15 can be more reliably recognized, and a stable refrigeration cycle can always be realized, and the reliability of the compressor 2 can be ensured.

In this embodiment, the case where the number of outdoor heat exchangers is two and the number of outdoor expansion valves is one has been described. By doing so, it can be implemented similarly.

[0040]

As described above, according to the present invention, a seal is provided between a branch point of the plurality of outdoor heat exchangers between the compressor and the plurality of outdoor heat exchangers and the outdoor heat exchanger. With a stop valve, discharge pressure detection means for detecting the pressure on the discharge side of the compressor, and a detection value of the discharge pressure detection means as an input,
Sealing valve control means for controlling the opening and closing of the sealing valve.

Therefore, even in the case of a cooling operation in which the outside air temperature is low or the number of indoor units operating is small and the cooling load is too small, the discharge pressure is constantly monitored.
Even if the pressure drops abnormally as in 5 MPa, the sealing valve is closed, the refrigerant is prevented from flowing into one of the outdoor heat exchangers, and the condensing cerebral power can be instantaneously reduced, and the discharge pressure rises responsively. .

That is, always ensure the reliability of the compressor,
An advantageous effect is obtained in that a stable refrigeration cycle with good response can be formed and cooling operation corresponding to a wide range of loads can be realized.

Further, a sealing valve is provided between a branch point of the plurality of outdoor heat exchangers between the compressor and the plurality of outdoor heat exchangers and the outdoor heat exchanger, and a discharge valve of the compressor is provided. Pressure detection means for detecting pressure on the suction side, suction pressure detection means for detecting pressure on the suction side of the compressor, and a detection value of the discharge pressure detection means and a detection value of the suction pressure detection means as inputs. Sealing valve control means for controlling the opening and closing of the sealing valve.

Therefore, even in the case of a cooling operation in which the outside air temperature is low or the number of indoor units in operation is small and the cooling load is too small, since the compressor is constantly monitored, the compression ratio is abnormally lowered to, for example, 2.0. This is prevented beforehand by closing the sealing valve, and the advantageous effects of always ensuring the reliability of the compressor and realizing a stable refrigeration cycle can be obtained.

A sealing valve is provided between a branch point of the plurality of outdoor heat exchangers between the compressor and the plurality of outdoor heat exchangers and the outdoor heat exchanger, and a discharge valve of the compressor is provided. Pressure detecting means for detecting the pressure on the suction side, suction pressure detecting means for detecting the pressure on the suction side of the compressor, indoor load detecting means for detecting the load on the indoor unit, and outdoor detecting the load on the outdoor unit Opening and closing the sealing valve by inputting a load detection unit, a detection value of the discharge pressure detection unit, a detection value of the suction pressure detection unit, a detection value of the indoor load detection unit, and a detection value of the outdoor load detection unit. And sealing valve control means for controlling the pressure.

Therefore, when the compressor is started or when the compression ratio temporarily drops due to a sudden change in the indoor load, the external unit temperature, the indoor temperature, and the indoor unit operating capacity are constantly monitored. In addition, it is possible to prevent an erroneous operation in which the sealing valve is closed due to an excessive decrease in the compression ratio and the discharge pressure is abnormally increased.

That is, it is possible to more reliably recognize the necessity of the sealing valve, and it is possible to obtain an advantageous effect that a stable refrigeration cycle is always realized and a higher reliability of the compressor can be secured.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram showing an air conditioner according to Embodiment 1 of the present invention.

FIG. 2 is a control block diagram of a sealing valve showing the air conditioner according to the embodiment.

FIG. 3 is a control flowchart of a sealing valve showing the air conditioner according to the embodiment.

FIG. 4 is a refrigeration cycle diagram showing an air conditioner according to Embodiment 2 of the present invention.

FIG. 5 is a control block diagram of a sealing valve showing the air conditioner according to the embodiment.

FIG. 6 is a control flowchart of a sealing valve showing the air conditioner according to the embodiment.

FIG. 7 is a refrigeration cycle diagram showing an air conditioner according to Embodiment 3 of the present invention.

FIG. 8 is a control block diagram of a sealing valve showing the air conditioner according to the embodiment.

FIG. 9 is a control flowchart of a sealing valve showing the air conditioner according to the embodiment.

FIG. 10 is a refrigeration cycle diagram showing a conventional air conditioner.

[Explanation of symbols]

 2 Compressor 3 Four-way valve 4 Discharge pressure detection means 12 Outdoor expansion valve 13, 14 Outdoor heat exchanger 15 Sealing valve 18, 21, 25 Sealing valve control means 19, 22, 26 Outdoor unit 20 Suction pressure detecting means 23 Indoor load detecting means 24 Outdoor load detecting means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Hayashi 4-5-2-5 Takaidahondori, Higashiosaka-shi, Osaka Matsushita Refrigeration Co., Ltd.

Claims (3)

[Claims] 1. A compressor, a plurality of outdoor heat exchangers, an outdoor expansion valve, a branch point of the plurality of outdoor heat exchangers between the compressor and the plurality of outdoor heat exchangers, and the chamber. An outdoor unit having a sealing valve provided between outer heat exchangers, a discharge pressure detecting means for detecting a pressure on a discharge side of the compressor, and the sealing valve having a detection value of the discharge pressure detecting means as an input. An air conditioner comprising: a sealing valve control unit that controls opening and closing of the air conditioner. 2. An opening / closing of the sealing valve is controlled by inputting a detection value of a suction pressure detecting means for detecting a pressure on a suction side of a compressor, a detection value of a discharge pressure detecting means, and a detection value of the suction pressure detecting means. The air conditioner according to claim 1, further comprising a sealing valve control unit. 3. A suction pressure detecting means for detecting a pressure on a suction side of a compressor, an indoor load detecting means for detecting a load on an indoor unit, an outdoor load detecting means for detecting a load on an outdoor unit, and a discharge pressure detecting. Sealing valve control means for controlling the opening and closing of the sealing valve by inputting the detected value of the means, the detected value of the suction pressure detecting means, the detected value of the indoor load detecting means, and the detected value of the outdoor load detecting means; The air conditioner according to claim 1, further comprising: