JPH08145483A - Air conditioner - Google Patents

Abstract

PURPOSE: To provide an air conditioner in which no inconvenience occurs even if a non-azeotrope refrigerant in which sealing composition substantially coincides with circulating composition is used. CONSTITUTION: This air conditioner comprises an outdoor unit 8 having a compressor 1, an outdoor heat exchanger 3, an outdoor expansion valve 6, an outdoor fan 4, etc., a plurality of indoor units 12 each having an indoor heat exchanger 9, an indoor expansion valve 10, an indoor fan 11, etc., to be connected by a pipe, and a refrigerant reservoir 5 provided between the valves 6 and 10, wherein a tube from the valve 6 and a tube from the valve 10 protrude to the vicinity of the bottom in the reservoir 5 to seal a non-azeotrope refrigerant.

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 an air conditioner using a non-azeotropic mixed refrigerant as a refrigerant.

[0002]

2. Description of the Related Art Conventionally, there is an air conditioner having a plurality of indoor units as shown in FIG. In FIG. 2, 1 is a compressor, 2 is a four-way valve for switching between cooling operation and heating operation, 3 is an outdoor heat exchanger, 4 is an outdoor fan, 5 is a refrigerant reservoir, 6 is an outdoor expansion valve, and 7 is an accumulator. And
These constitute the outdoor unit 8. Further, 9a and 9b are indoor heat exchangers, 10a and 10b are indoor expansion valves, and 11a and 1b.
1b is an indoor fan, and these are indoor units 12a, 12
b. When performing cooling with the indoor units 12a and 12b, the four-way valve 2 is switched as shown by the solid line in FIG. 2 and the outdoor heat exchanger 3 is used as a condenser, and the indoor heat exchangers 9a and 9b are used.
b acts as an evaporator. In addition, the indoor units 12a, 12
When heating is performed in b, the four-way valve 2 is switched as shown by the broken line in FIG. 2 to cause the outdoor heat exchanger 3 to act as an evaporator and the indoor heat exchangers 9a and 9b to act as condensers. As the refrigerant, HCFC22 which is a single refrigerant is generally used.

Here, in the cooling operation in which only the outdoor heat exchanger 3 acts as a condenser, in comparison with the heating operation in which a plurality of indoor heat exchangers (two units 9a and 9b in this embodiment) act as condensers. As a result, the refrigerant is overfilled, causing a problem such as an abnormal increase in discharge pressure. In order to avoid such a problem, the refrigerant liquefied in the outdoor heat exchanger 3 acting as a condenser during the cooling operation is liquefied in the refrigerant reservoir 5. In order to be able to store the refrigerant in the state, the refrigerant reservoir 5 has a two-phase state in which the liquid refrigerant enters from the bottom and exits from the top during the cooling operation, and is decompressed by the outdoor expansion valve 6 during the heating operation. Refrigerant is configured to enter at the top and exit at the bottom.

[0004]

However, from the viewpoint of protecting the global environment, it is considered that the ozone layer of the stratosphere is destroyed and HC
It has been decided that the FC22 will be completely abolished, and non-azeotropic mixed refrigerants are regarded as promising alternative refrigerants. With this non-azeotropic mixed refrigerant,
Since the liquid phase and the gas phase in the two-phase state have different compositions, there are the following problems when the non-azeotropic mixed refrigerant is applied to the above-described conventional air conditioner.

First, during the cooling operation, when it becomes difficult to ensure supercooling of the refrigerant in the outdoor heat exchanger 3 such as when the outside air temperature is high, the two-phase refrigerant flows into the refrigerant reservoir 5 from the bottom, Only the vapor phase refrigerant flows out from the top.
Therefore, a distillation action occurs in the refrigerant reservoir 5, the non-azeotropic mixed refrigerant containing a large amount of high boiling point components is stored in the refrigerant reservoir 5, and the refrigerant containing a large amount of low boiling point components is stored in the refrigeration cycle. Circulate. Since the refrigerant composition circulating in the refrigeration cycle is different from the preset encapsulation composition, the refrigerant superheat degree or supercooling degree at each heat exchanger outlet or the refrigerant superheat degree at the compressor 1 suction portion is detected. Becomes difficult,
There are also problems such as a decrease in efficiency due to a change in the refrigerant composition, a problem such as an increase in discharge temperature, a decrease in efficiency due to operation in an excessive refrigerant condition, and an abnormal increase in compressor load due to an increase in discharge pressure.

During the heating operation, the indoor heat exchanger 9a,
Although 9b acts as a condenser, the amount of refrigerant in the refrigeration cycle may become excessive due to the number of operating indoor units and the heating load, and the amount of refrigerant stored in the refrigerant reservoir 5 cannot be controlled with the conventional configuration. The excess refrigerant is stored in the accumulator 7. However, since the accumulator 7 has a configuration in which only the vapor phase refrigerant in the upper part of the accumulator 7 flows out so that the liquid refrigerant is not sucked into the compressor 1, a distillation action occurs like the refrigerant reservoir 5 during the cooling operation, and the accumulator 7 is generated. 7
The non-azeotropic mixed refrigerant containing a large amount of high boiling point components is stored therein, and the refrigerant containing a large amount of low boiling point components circulates in the refrigeration cycle. In this way, the refrigerant composition circulating in the refrigeration cycle is different from the preset enclosure composition,
It becomes difficult to detect the degree of refrigerant superheat or the degree of supercool at the outlet of each heat exchanger, or the degree of refrigerant superheat at the suction part of the compressor 1, and the saturation temperature changes in the indoor heat exchangers 9a and 9b that act as condensers. There are also problems such as insufficient capacity, reduced efficiency, and increased discharge temperature.

The present invention, in consideration of such problems of the conventional air conditioner, prevents the non-azeotropic mixed refrigerant composition circulating in the refrigeration cycle from being different from the enclosed composition even when the excess refrigerant exists. An object of the present invention is to provide an air conditioner using a non-azeotropic mixed refrigerant that does not destroy the ozone layer by optimizing the amount of refrigerant circulating in the refrigeration cycle.

[0008]

In order to achieve the above object, the present invention has an outdoor unit including a compressor, an outdoor heat exchanger, an outdoor expansion valve, an outdoor fan, etc., an indoor heat exchanger, an indoor expansion valve, and an indoor fan. Plural indoor units consisting of etc. are connected by piping, a refrigerant reservoir is provided between the outdoor expansion valve and the indoor expansion valve, and the piping from the outdoor expansion valve and the piping from the indoor expansion valve are respectively located at the bottom of the refrigerant reservoir. It is characterized in that it is connected so as to protrude to the vicinity and a non-azeotropic mixed refrigerant is enclosed.

The present invention further provides a superheat detector for detecting the degree of superheat of the refrigerant in the suction portion of the compressor, and the degree of supercooling of the refrigerant at the outlet of the outdoor heat exchanger during cooling or at the outlet of the indoor heat exchanger during heating. A supercooling degree detector that detects the temperature, a superheat degree controller that operates the indoor expansion valve during cooling or the outdoor expansion valve during heating so that the degree of superheat detected by the superheater detector falls within an appropriate range, and It is characterized by including a subcooling degree controller that operates an outdoor expansion valve during cooling or an indoor expansion valve during heating so that the degree of subcooling detected by the cooling degree detector falls within an appropriate range. is there.

[0010]

In the air conditioner having the above-mentioned structure, the pipe from the outdoor expansion valve and the pipe from the indoor expansion valve are connected to the bottom of the refrigerant reservoir so as to project to the vicinity of the bottom of the refrigerant reservoir. In most cases, both the refrigerant flowing into the reservoir and the refrigerant flowing out are in a two-phase state or a liquid refrigerant, so that no distillation action occurs, and the composition of the enclosed non-azeotropic mixed refrigerant and the non-azeotropic refrigerant actually circulating in the refrigeration cycle. It is possible to prevent the difference in the composition of the boiling mixed refrigerant, making it easy to detect the degree of refrigerant superheat or supercooling at the outlet of each heat exchanger or the degree of refrigerant superheat at the compressor suction part. Problems such as insufficient capacity, reduced efficiency, and increased discharge temperature due to changes in the saturation temperature in the vessel can be resolved.

Further, by operating the indoor expansion valve and the outdoor expansion valve so that the degree of superheat of suction by the compressor and the degree of supercooling at the outlet of the heat exchanger acting as a condenser are within proper ranges,
Change the amount of refrigerant flowing in or out of the refrigerant reservoir,
Refrigerant storage amount can be adjusted, and even in air conditioners that use non-azeotropic mixed refrigerant, the circulating refrigerant composition does not differ from the enclosed composition, and excess refrigerant is stored, resulting in reduced efficiency due to operation in an excessive refrigerant state. Also, problems such as abnormal increase in compressor load due to increase in discharge pressure can be solved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments.

FIG. 1 is a block diagram of an air conditioner according to an embodiment of the present invention. In FIG. 1, 1 is a compressor, 2 is a four-way valve for switching between cooling operation and heating operation, 3 is an outdoor heat exchanger, 4 is an outdoor fan, 5 is a refrigerant reservoir, 6 is an outdoor expansion valve, and 7 is an accumulator. And these constitute the outdoor unit 8. Further, 9a and 9b are indoor heat exchangers, 10a,
Reference numeral 10b is an indoor expansion valve, 11a and 11b are indoor fans, and these constitute indoor units 12a and 12b. Here, in the refrigerant reservoir 5, the piping from the outdoor expansion valve 6 and the piping from the indoor expansion valves 10a and 10b are respectively the refrigerant reservoir 5
It is connected so as to protrude to the vicinity of the bottom inside.

Reference numeral 13 is a superheat detector for detecting the degree of superheat of the refrigerant at the suction portion of the compressor.
The pressure is measured, the saturated gas temperature is calculated by the saturated gas temperature correlation equation with the preset composition of the non-azeotropic mixed refrigerant, and the superheat degree is determined by the difference between the measured temperature and the saturated gas temperature. Further, 14 is a supercooling degree detector during cooling, and 1
Reference numerals 5a and 15b denote supercooling degree detectors during heating. For example, like the superheat degree detector 13, the temperature and pressure of the refrigerant are measured and the pressure and preset composition of the non-azeotropic mixed refrigerant are measured. The saturated liquid temperature is calculated by the saturated liquid temperature correlation formula, and the difference between the measured temperature and the saturated liquid temperature indicates the degree of supercooling by the cooling supercooling degree detector 14 during cooling or the heating supercooling degree detectors 15a and 15b during heating. To decide. Again 16
Is a superheat controller, which operates the indoor expansion valves 10a and 10b during cooling and operates the outdoor expansion valve 6 during heating so that the superheat determined by the superheat detector 13 falls within an appropriate range. Further, reference numeral 17 denotes a supercooling degree controller, which is a cooling supercooling degree detector 14 or a heating supercooling degree detector 15a,
The outdoor expansion valve 6 is operated during cooling or the indoor expansion valves 10a and 10b during heating so that the degree of supercooling determined by 15b falls within an appropriate range.

Next, the operation during the cooling operation will be described.

During the cooling operation, the four-way valve 2 is set so that the outdoor heat exchanger 3 acts as a condenser and the indoor heat exchangers 9a and 9b both act as evaporators. At this time, the gas refrigerant compressed in the compressor 1 and having a high temperature and high pressure is introduced into the outdoor heat exchanger 3 via the four-way valve 2 and exchanges heat with the outdoor air to become a liquid refrigerant. Then, after passing through the outdoor expansion valve 6 and the refrigerant reservoir 5, the indoor expansion valves 10a and 10b decompress to become a low-temperature low-pressure two-phase refrigerant, and the indoor heat exchangers 9a and 9b exchange heat with the indoor air to cool the gas refrigerant. Then, it is compressed by the compressor 1 again via the four-way valve 2 and the accumulator 7.

Further, since only the outdoor heat exchanger 3 acts as a condenser during the cooling operation, a plurality of indoor heat exchangers (two units 9a and 9b in this embodiment) act as a condenser during heating operation. In comparison, the refrigerant becomes excessive and the degree of subcooling at the outlet of the outdoor heat exchanger 3 acting as a condenser increases, but the degree of subcooling during cooling is detected by the degree of supercooling detector 14 to control the degree of supercooling. The outdoor expansion valve 6 is operated in the opening direction so that the degree of supercooling of the device 17 is within an appropriate range.

At the same time, when the refrigerant becomes excessive, the refrigerant is not fully evaporated in the indoor heat exchangers 9a and 9b and the superheat degree at the suction portion of the compressor 1 or the inlet side of the accumulator 7 decreases, but the superheat detector 13 Detecting the degree of superheat, the superheat controller 16 operates the indoor expansion valves 10a, 10b in the closing direction so that the degree of superheat falls within an appropriate range. That is, the outdoor expansion valve 6 connected to the inlet side of the refrigerant reservoir 5 is opened,
By operating the indoor expansion valves 10a, 10b connected to the outlet side in the closing direction, the amount of refrigerant flowing into the refrigerant reservoir 5 increases and the amount of refrigerant flowing out of the refrigerant reservoir 5 decreases. A part is stored in the refrigerant reservoir 5.

At this time, the pipes from the outdoor expansion valve 6 and the pipes from the indoor expansion valves 10a and 10b, which serve as the inlet and the outlet of the refrigerant reservoir 5, are connected so as to project to the bottom of the refrigerant reservoir 5, respectively. Since most of the inflowing and outflowing refrigerants are in a liquid state in most cases, no distillation action occurs, and the refrigerant circulating in the refrigeration cycle and the refrigerant reservoir 5
Since the refrigerant stored therein has the same composition, that is, substantially matches the enclosed composition, it is easy to detect the degree of superheat or the degree of supercooling, and it is possible to eliminate problems such as a decrease in efficiency and an increase in discharge temperature due to a change in refrigerant composition. Furthermore, the superheat detector 13
Superheat control until both the degree of superheat detected by and the degree of supercool detected by the supercooling degree detector during cooling 14 are within proper ranges (that is, the amount of refrigerant circulating in the refrigeration cycle is proper). Since the indoor expansion valve 10a, 10b or the outdoor expansion valve 6 is continuously operated by the cooler 16 or the supercooling degree controller 17, all the excess refrigerant can be stored in the refrigerant reservoir 5, and the efficiency decrease due to the excessive refrigerant state and Also, the problem of abnormal increase of compressor load due to increase of discharge pressure can be solved.

Next, the operation during heating will be described.

During the heating operation, the four-way valve 2 is set so that the outdoor heat exchanger 3 acts as an evaporator and the indoor heat exchangers 9a and 9b both act as condensers. At this time, the gas refrigerant that has been compressed by the compressor 1 and has a high temperature and high pressure is introduced into the indoor heat exchangers 9a and 9b through the four-way valve 2 and exchanges heat with the indoor air to become a liquid refrigerant. And the indoor expansion valves 10a, 10b,
After being decompressed by the outdoor expansion valve 6 via the refrigerant reservoir 5, it becomes a low-temperature low-pressure two-phase refrigerant, and by the outdoor heat exchanger 3 exchanging heat with the outdoor air to become a low-temperature gas refrigerant, passing through the four-way valve 2 and the accumulator 7. It is compressed by the compressor 1 again.

Further, during the heating operation, the amount of refrigerant in the refrigeration cycle may become excessive due to the number of operating indoor units and the heating load, and the indoor heat exchangers 9a and 9a functioning as condensers.
Although the degree of supercooling at the b outlet increases, the degree of supercooling during heating is detected by the degree of supercooling detectors 15a and 15b, and the degree of supercooling is controlled by the degree of supercooling controller 17 to be within an appropriate range. The indoor expansion valves 10a and 10b are operated in the opening direction.

At the same time, when the refrigerant becomes overheated, the refrigerant cannot be fully evaporated in the outdoor heat exchanger 3 and the superheat degree at the suction part of the compressor 1 or the inlet side of the accumulator 7 decreases, but the superheat detector 13 shows the superheat degree. To detect the superheat degree controller 16
Then, the outdoor expansion valve 6 is operated in the closing direction so that the degree of superheat falls within an appropriate range. That is, the refrigerant flowing into the refrigerant reservoir 5 is operated by operating the indoor expansion valves 10a and 10b connected to the inlet side of the refrigerant reservoir 5 in the opening direction and operating the outdoor expansion valve 6 connected to the outlet side in the closing direction. Is increased and the refrigerant flowing out of the refrigerant reservoir 5 is decreased, so that a part of the refrigerant is stored in the refrigerant reservoir 5.

At this time, the piping from the outdoor expansion valve 6 and the piping from the indoor expansion valves 10a and 10b are connected to both the inlet and the outlet of the refrigerant reservoir 5 so as to project to the vicinity of the bottom of the refrigerant reservoir 5, respectively. Therefore, since the inflowing and outflowing refrigerants are in a liquid state or a two-phase state in most cases, the distillation action does not occur, and the refrigerant circulating in the refrigeration cycle and the refrigerant stored in the refrigerant reservoir 5 have the same composition. That is, since it substantially matches the enclosed composition, it is easy to detect the degree of superheat or supercooling, and the capacity is insufficient or the efficiency is reduced due to a change in the saturation temperature in the condenser (indoor heat exchanger 9a, 9b) due to a change in the refrigerant composition. It is also possible to eliminate problems such as increase in discharge temperature. Furthermore, the superheat detected by the superheat detector 13,
Until the supercooling degree detected by the heating supercooling degree detectors 15a and 15b is both within a proper range (that is, the amount of refrigerant circulating in the refrigeration cycle is proper), the superheat degree controller 16 or the supercooling degree Since the controller 17 continues to operate the outdoor expansion valve 6 or the indoor expansion valves 10a, 10b, all the surplus refrigerant can be stored in the refrigerant reservoir 5, resulting in a decrease in efficiency due to an excessive refrigerant state and an increase in discharge pressure. Problems such as abnormal increase of compressor load can be solved.

Although the air conditioner in which two indoor units are connected has been described in this embodiment, the number of indoor units does not matter, and the outdoor unit is connected with the indoor unit, such as a water heater. The present invention also includes such devices.

Further, in this embodiment, the indoor expansion valve or the outdoor expansion valve is operated so that the superheat degree of the refrigerant in the compressor suction part is within an appropriate range, but the heat exchanger outlet acting as an evaporator It is clear that the same result can be obtained by using the superheat degree of, and it is included in the present invention.

[0027]

As is apparent from the above description, the present invention provides the refrigerant reservoir between the outdoor expansion valve and the indoor expansion valve, and the piping from the outdoor expansion valve and the piping from the indoor expansion valve are refrigerants. By connecting to the vicinity of the bottom of the reservoir and enclosing a non-azeotropic mixed refrigerant, the occurrence of a distillation action in the refrigerant reservoir is prevented, and a refrigerant circulating in the refrigeration cycle is used. Since the refrigerant stored in the refrigerant reservoir has the same composition, that is, it almost matches the enclosed composition, it is easy to detect the degree of superheat or supercooling, and due to changes in the saturation temperature in the heat exchanger due to changes in the refrigerant composition, etc. Problems such as insufficient capacity, reduced efficiency, and increased discharge temperature can be resolved.

Further, according to the present invention, the degree of superheat of the refrigerant at the suction portion of the compressor and the degree of supercooling of the refrigerant at the outlet of the outdoor heat exchanger during cooling or at the outlet of the indoor heat exchanger during heating are within appropriate ranges. As described above, the superheat degree controller that operates the indoor expansion valve during cooling or the outdoor expansion valve during heating and the outdoor expansion valve or the outdoor expansion valve during cooling so that the degree of supercooling detected by the supercooling degree detector is within an appropriate range. By having a supercooling degree controller that operates the indoor expansion valve during heating,
Even when surplus refrigerant is generated, the surplus refrigerant is stored in the refrigerant reservoir, so that problems such as a decrease in efficiency due to an excessive refrigerant state and an abnormal increase in compressor load due to an increase in discharge pressure can be solved.

That is, an air conditioner using a non-azeotropic mixed refrigerant that does not destroy the ozone layer can be realized.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of a conventional air conditioner.

[Explanation of symbols]

 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Outdoor fan 5 Refrigerant reservoir 6 Outdoor expansion valve 7 Accumulator 8 Outdoor unit 9a, 9b Indoor heat exchanger 10a, 10b Indoor expansion valve 11a, 11b Indoor fan 12a, 12b Indoor unit 13 Superheat Detector 14 Cooling Supercooling Detector 15a, 15b Heating Supercooling Detector 16 Superheat Controller 17 Supercooling Detector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Yoshida 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A pipe connection between an outdoor unit including a compressor, an outdoor heat exchanger, an outdoor expansion valve, an outdoor fan, and a plurality of indoor units including an indoor heat exchanger, an indoor expansion valve, an indoor fan, etc. Then, a refrigerant reservoir is provided between the outdoor expansion valve and the indoor expansion valve, and the pipe from the outdoor expansion valve and the pipe from the indoor expansion valve are respectively projected to the vicinity of the bottom of the refrigerant reservoir. An air conditioner that is connected and filled with a non-azeotropic mixed refrigerant. 2. A superheat detector for detecting the degree of superheat of the refrigerant at the suction part of the compressor, and a supercool degree of the refrigerant at the outlet of the outdoor heat exchanger during cooling or at the outlet of the indoor heat exchanger during heating. A supercooling degree detector for detecting, and a superheat degree controller for operating the indoor expansion valve during cooling or the outdoor expansion valve during heating so that the degree of superheat detected by the superheater detector is within an appropriate range. A subcooling degree controller that operates the outdoor expansion valve during cooling or the indoor expansion valve during heating so that the degree of subcooling detected by the subcooling degree detector is within an appropriate range. The air conditioner according to claim 1, which is characterized in that.