JPH0781752B2 - Refrigeration equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a refrigerating apparatus using a mixed refrigerant.

2. Description of the Related Art A refrigeration system using a mixed refrigerant can perform capacity control and performance improvement by varying the composition ratio of the refrigerant circulating inside the cycle.

Conventionally, a rectification separation method utilizing a difference in boiling point has been used as a method for varying the composition of the refrigerant circulating in the cycle of a refrigeration system using a non-azeotropic mixed refrigerant (for example, Japanese Patent Laid-Open No. 61- No. 101757).

An example of the refrigerating apparatus using the rectification separation system will be described below with reference to FIGS. 3 and 4.

FIG. 3 is a refrigeration cycle diagram showing a conventional example, and FIG. 4 is a sectional view of a rectification column for changing the composition ratio of the non-azeotropic mixed refrigerant.

In FIG. 3, 1 is a compressor, 2 is a condenser, 3 is a main expansion device, and 4 is an evaporator, which are annularly connected to each other to form a main circuit. On the other hand, the outlet of the condenser 2 and the inlet of the rectification tower 6 are piped.
The heater 5 is connected to the pipe 10 by heat exchange. Further, the lower outlet of the rectification column 6 and the inlet of the evaporator 4 of the main circuit are connected via the auxiliary expansion device 7 by the pipes 11 and 12. Further, a cooler 8 and a reservoir 9 are provided above the rectification column 6, and the reservoir 9 is connected to the rectification column 6 in an annular shape by pipes 13 and 14. Also, cooler 8 and piping
13 and 13 are connected by heat exchange. Here, as the heat source of the heater 5 and the cooler 8, the discharge gas and the suction gas of the compressor 1 are used. As the refrigerant, a non-azeotropic mixed refrigerant composed of two kinds of refrigerants having different boiling points is used.

In FIG. 4, 601 is the main body of the rectification tower 6, 602 is a packing material,
603 and 604 are filler holders.

The operation of the refrigerating apparatus configured as described above will be described below.

First, the case where rectification separation is not performed will be described.

A part of the high-pressure liquid refrigerant discharged from the condenser 2 is branched by the pipe 10. At this time, if the valve opening of the sub-throttle device 7 is increased, the flow rate of the branch refrigerant branched to the pipe 10 is increased, and the heating of the heater 5 is insufficient, so that steam is not generated and liquid is discharged from the lower inlet of the rectification column 6. Refrigerant flows in. As a result, the rectification action does not proceed, and the liquid refrigerant rises inside the rectification tower 6, enters the reservoir 9 through the pipe 13, and returns to the rectification tower 6 through the pipe 14. Then, the pressure is reduced by the sub expansion device 7 and merges with the main circuit side refrigerant.

In this way, the composition ratio of the low boiling point component inside the reservoir 9 does not rise, so that the composition ratio of the main circuit becomes equal to the refrigerant charging ratio.

Next, the case of performing rectification separation will be described.

When the valve opening of the sub-throttle device 7 is reduced from the above state, the flow rate of the branched refrigerant decreases, and the liquid refrigerant branched from the condenser 2 is heated by the heater 5 and partially vaporized. It flows in from the lower entrance of the distillation column 6. This gas component rises in the clearance of the packing material 602 in the rectification tower 6, enters the cooler 8 through the pipe 13 from the upper outlet, and is liquefied as a refrigerant to enter the reservoir 9.
The drop A between the reservoir 9 and the return pipe 14 of the rectification tower 6 is preset.
A part of the liquid refrigerant from the reservoir 9 is returned to the rectification column 6 again through the pipe 14 due to the drop A, and the packing material 602 is provided.
The rectifying column stores the refrigerant having a large amount of low boiling point components in the reservoir 9 by making a rectifying action by heat exchange and mass transfer by making a vapor-liquid contact with the vapor that rises halfway through the gap. From the lower part of 6, the refrigerant with a low low boiling point component is pipe 11,
It flows into the main circuit through the auxiliary expansion device 7 and the pipe 12.

Therefore, the low boiling point component ratio of the main circuit decreases and the high boiling point component ratio increases.

As described above, by controlling the valve opening of the auxiliary expansion device 7, the amount of steam generated is adjusted to perform rectification separation, and the composition ratio of the refrigerant stored in the reservoir 9 is changed,
The composition ratio of the main circuit refrigerant can be made variable.

Problems to be Solved by the Invention However, the above configuration has the following problems.

First of all, if the rectification tower is installed tilted, the refrigerant vapor and the liquid refrigerant go up and down the wall surface of the tower, making it difficult for gas-liquid contact to occur, heat exchange and mass transfer are reduced, and rectification separation performance is also reduced. To do. Therefore, it is necessary to install the rectification column vertically.

Secondly, in the height relationship between the upper return port of the rectification column and the reservoir, a certain constant drop A shown in FIG. 4 is set so that the liquid stored in the reservoir returns to the rectification column due to potential energy. is necessary.

Thirdly, in order to carry out rectification separation, it is necessary to carry out heating and the like and to inject the refrigerant vapor from the lower part of the rectification column.

Fourthly, in order to improve the rectification separation performance, it is necessary to put a packing material inside the column to increase the height and the number of theoretical plates.

Fifth, the flow rate of the branched refrigerant during the rectification separation depends on the capabilities of the heater and the cooler. If the flow rate is too large, the rectification action does not proceed as described above, so the flow rate must be reduced.
Therefore, rectification separation requires time.

Sixth, since the rectification separation utilizes the difference in boiling points, it cannot be used for azeotropic mixed refrigerants having similar boiling points.

Seventh, in the conventional example, the case where the low boiling point refrigerant is stored to reduce the low boiling point component ratio of the main circuit has been described. However, the high boiling point refrigerant is also stored to increase the refrigerant composition ratio of the main circuit in a wide range. In order to make it variable, a reservoir and a heater are needed under the separator.

As described above, there are many restrictions on mounting and installation, and there are problems that the device is large and complicated.

In view of the above problems, it is an object of the present invention to expand the variable width of the refrigerant composition ratio, eliminate restrictions on mounting and installation of components of a separation circuit, and reduce the size and simplification of the separation circuit.

Means for Solving the Problems In order to solve the above problems, the present invention encapsulates a plurality of types of refrigerants, and the permeation rate of a specific refrigerant among the plurality of types of refrigerants is higher than the permeation rate of other refrigerants. In addition to having an inlet pipe connected between the condenser and the main expansion device, it has a refrigerant separator with an outlet pipe and a permeated refrigerant outlet pipe, and one end is connected between the main expansion device and the evaporator. And a first connecting pipe having a first auxiliary expansion device on the evaporator side of the reservoir and the storage device, one end connected between the main expansion device and the evaporator, and a second auxiliary expansion device. A second connection pipe is provided, and a four-way valve for switchably connecting the outlet pipe and one of the first and second connection pipes and the permeated refrigerant outlet pipe and the other of the first and second connection pipes are provided. Is.

Effect The present invention can separate refrigerants not only for non-azeotropic mixed refrigerants but also for azeotropic mixed refrigerants, thereby eliminating restrictions on mounting and installation of components of the separation circuit, and achieving miniaturization and simplification of the separation circuit. In addition, either the permeating refrigerant or the non-permeating refrigerant of the functional film can be selected and stored by only one reservoir.

Example First, an experimental result that clarifies that a functional film can be used for refrigerant separation will be described.

FIG. 2 shows an embodiment of a refrigerant separator (hereinafter referred to as a separator) using a functional film.

In the figure, the separator main body 102 is partitioned into a high pressure side space a and a low pressure side space b by a mesh-shaped holder 104, and the functional film 103 is installed on the high pressure side of the holder 104. Further, the separator main body 102 includes a high pressure refrigerant inlet pipe 105, an outlet pipe 106, and a permeated refrigerant outlet pipe 10.
7 is provided.

In the separator with the above structure, a benzene solution of dimethyl silicone was spread on water as a functional film to make it an ultra-thin film, and then a thin film formed by transfer film formation on a porous polypropylene film (Ceraneys Co., Ltd .: Jura Guard) was prepared. The case of separating a mixed refrigerant of R-22 and R-13B1 used as a molecular composite film will be described.

The mixed refrigerant pressurized by the compressor or the like is sent from the inlet pipe 105 to the high pressure side space a in the separator body 102. Here, due to the pressure difference between the high pressure side space a and the low pressure side space b, a part of the refrigerant permeates into the low pressure side space b and is discharged from the permeated refrigerant outlet pipe 107. At this time, R-22 is more likely to permeate than R-13B1, and the ratio of R-22 in the refrigerant discharged from the permeated refrigerant outlet pipe 107 is higher than that in the inlet pipe 105. On the other hand, the high pressure refrigerant outlet pipe 106 without passing through the functional film 103.
The more discharged refrigerant composition has a lower R-22 ratio.

Table 1 shows an example of the experimental results.

In Table 1 above, the case where the refrigerant vapor is introduced from the artificial pipe of the separator 101 is shown, but the refrigerant liquid or the mixture of the vapor and the liquid can be introduced to separate the refrigerant vapor.

As described above, it has been clarified that the refrigerant can be separated by using the functional film.

In the previous experiment, a benzene solution of dimethyl silicone was spread on water to form an ultra-thin film, and then a polypropylene porous film (Ceraney's: Juraguard)
Although the polymer composite film formed by transfer film formation is used, natural rubber, polyethylene, polyvinyl acetate or the like may be used as the non-porous polymer film material other than dimethyl silicone.

Further, even if a porous polymer membrane, a biological membrane or the like is used and the refrigerant is separated by utilizing the ratio of permeation amounts, it does not depart from the gist of the present invention.

An embodiment of the refrigeration cycle using the functional film will be described below with reference to FIG.

FIG. 1 shows an embodiment in which a non-azeotropic mixed refrigerant of R-22 and R-13B1 is used as the refrigerant.

In the figure, 21 is a compressor, 22 is a condenser, 23 is a main expansion device, and 24 is an evaporator, which are sequentially connected in an annular fashion to form a main circuit. On the other hand, the inlet pipe 105 of the separator 101 having the above structure is connected to the high pressure side before the main expansion device 23, and the outlet pipe 106 and the permeated refrigerant outlet pipe 107 are connected to the four-way valve 26. Further, from the four-way valve 25 as a selection means for selecting the refrigerant to be stored, it is connected to the low pressure side after the main expansion device 23 via the connection pipe 108, the reservoir 26, the auxiliary expansion device 27, and the other is connected. It is connected to the low-pressure side after the main expansion device 23 via the pipe 109 and the sub expansion device 28, and the communication from the outlet pipe 106 and the permeated refrigerant outlet pipe 107 is established by energizing the four-way valve coil (not shown). It can be switched.

Here, the connection pipe 108 is connected to the cooler 29 in a heat exchange manner.

The operation of the refrigeration cycle configured as above will be described below.

First, the case where the refrigerant is not separated will be described.

The refrigerant vapor compressed by the compressor 21 is cooled and liquefied by the condenser 22 and reduced in pressure by the main expansion device 23, and then the evaporator.
Evaporate at 24 and return to compressor 21. Here, the sub diaphragm device 27,
When 28 are opened appropriately according to the opening degree of the main expansion device 23, the liquid refrigerant branched from the front of the main expansion device 23 is separated by the separator.
While flowing into 101, part is returned to the inlet of the evaporator 24 through the four-way valve 25, the connecting pipe 108, the reservoir 26, the sub-throttle device 27 from the outlet pipe 106 without passing through the functional film 103.
The rest permeates the functional film 103, and the four-way valve 25 from the outlet pipe 107,
It is returned to the inlet of the evaporator 24 via the connection pipe 109 and the sub expansion device 28. Therefore, it becomes equal to the charging ratio of the refrigerant circulating in the cycle.

Next, a case where the refrigerant is separated will be described.

First, when the non-permeable refrigerant is stored, the sub-throttle device 28 is appropriately opened from the above state according to the opening degree of the main throttle device 23, and when the sub-throttle device 27 is fully closed, the branched liquid refrigerant is separated.
R-22, which flows into 1 and easily permeates the functional film 103, exits the permeated refrigerant outlet pipe 107, and is returned to the inlet of the evaporator 24 via the four-way valve 25, the connection pipe 109, and the sub expansion device 28.

On the other hand, the R-13B1 which is difficult to permeate the functional film 103 has an outlet pipe 106.
Through the four-way valve 25 and the connecting pipe 108, and is cooled by the cooler 29 and stored in the reservoir 26. Therefore, the R-13B1 ratio of the main circuit decreases and the R-22 ratio increases.

When storing the permeated refrigerant, the auxiliary expansion device 28 is similarly used.
Is opened appropriately according to the opening degree of the main expansion device 23, the sub expansion device 27 is fully closed, and the flow path of the four-way valve 25 is switched by energizing the four-way valve coil. As a result, the branched liquid refrigerant flows into the separator 101 and does not easily pass through the functional film 103.
13B1 exits the outlet pipe 106 and is returned to the inlet of the evaporator 24 via the four-way valve 25, the connection pipe 109, and the auxiliary expansion device 28. On the other hand, R-22, which easily permeates the functional film 103, exits the outlet pipe 107, is cooled by the cooler 29 via the four-way valve 25 and the connection pipe 108, and is stored in the reservoir 26 as a liquid refrigerant. Therefore, the R-22 ratio of the main circuit decreases and the R-13B1 ratio increases.

As described above, according to the present embodiment, R-13B1 which hardly permeates the functional membrane or R-22 which easily permeates the functional membrane is arbitrarily selected and stored in one reservoir to store the refrigerant composition in the main circuit. The ratio can be varied over a wide range, and the refrigerant composition of the main circuit can be varied according to the purpose of high efficiency, high capacity, etc. without the need for a heater or the like. Further, since there is no restriction on the mounting of the components of the separation circuit, the separation circuit can be downsized and simplified.

The point that the refrigerant liquid or the mixture of vapor and liquid can be separated even when flowing in will be described.

First, the transmission speed and the separation coefficient α are defined as follows.

R = Q / t = q / (A ・ ΔP) (cc / (sec ・ cm ²・ cmHg)) α = Ry / Rz y: Refrigerant on the permeating side z: Refrigerant on the non-permeating side Q: Permeability coefficient t: Thickness q : Permeation flow rate A: Membrane area ΔP: Transmembrane differential pressure In this definition, the single gas is as shown in Fig. 5 (a), and the gas-liquid mixed gas is as in Fig. 5 (b). Here, α = 1 is a state in which separation is impossible. As the differential pressure increases, the separation performance improves as shown in FIG. 5 (a) for the simple substance gas, but has the opposite tendency for the gas-liquid mixed gas as shown in FIG. 5 (b). Here, when the horizontal axis is the gas ratio of the gas-liquid mixed gas (dryness x), it becomes as shown in FIG. 5 (c).

Next, the material of the functional film will be described.

Although dimethyl corn was used in the above examples, natural rubber, polyethylene, polyvinyl acetate, etc. may be used as the non-porous polymer membrane material other than dimethyl corn.
Further, a porous polymer membrane, a biological membrane or the like may be used to perform the refrigerant separation by utilizing the ratio of permeation amounts.

Further, the separation ability due to the pressure difference different from that in Table 1 will be described.

In the case of the gas-liquid mixed gas as shown in FIG. 5 (b), the separation performance is reduced due to the differential pressure, but as shown in FIG. 1, the sub expansion device 28 is on the outlet side of the separator and its opening Since the opening degree is appropriately opened according to the opening degree of the main expansion device 23 at the time of separation, the differential pressure across the membrane should rise to the differential pressure between the high pressure side (condenser outlet pressure) and the low pressure side (evaporator inlet pressure). Actually, it is about 4 to 5 kg / cm ² G depending on the permeation flow rate and the membrane resistance. Therefore, since the pressure becomes equal to or lower than the differential pressure in Table 1, the separation performance does not significantly decrease.

EFFECTS OF THE INVENTION As described above, according to the present invention, one of a refrigerant that hardly permeates a functional film and a refrigerant that easily permeates is selected to
By storing in one reservoir, it is possible to change the composition of a plurality of types of refrigerant in the main circuit without the need for a heater or the like. And when you want to make the best use of the characteristics of the refrigerant that easily permeates the functional film, store the refrigerant that is difficult to permeate and circulate the easily permeable refrigerant in the main circuit. Sometimes it stores a refrigerant that is easy to permeate,
It is possible to circulate a refrigerant that is difficult to permeate in the main circuit. Moreover, there are no restrictions on the mounting and installation of the components of the separation circuit. Therefore, there is an effect that the separation circuit can be downsized and simplified.

[Brief description of drawings]

FIG. 1 is a refrigerating cycle diagram of a refrigerating apparatus in one embodiment of the present invention, FIG. 2 is a detailed sectional view of a separator used in the refrigerating cycle, FIG. 3 is a refrigerating cycle diagram in a conventional example, and FIG. Detailed sectional views of the rectification column, and FIGS. 5A to 5C are characteristic diagrams of the separation coefficient α. 21 ... Compressor, 22 ... Condenser, 23 ... Main throttle device, 24 ...
… Evaporator, 26 …… Reservoir, 101 …… Separator, 103 …… Functional membrane.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koji Murozono 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Akira Fujitaka, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 56) References JP-A-63-238367 (JP, A)

Claims (1)

[Claims] 1. A main circuit in which a compressor, a condenser, a main expansion device, and an evaporator are sequentially connected in an annular shape, and a plurality of types of refrigerants are enclosed in the main circuit. A refrigerant separator having a functional film higher than the permeation ratio of the refrigerant, and having an outlet pipe and a permeated refrigerant outlet pipe in addition to the inlet pipe connected between the condenser and the main throttle device, the main throttle One end is connected between the device and the evaporator,
A reservoir and a first connecting pipe having a first auxiliary expansion device on the evaporator side of the reservoir, and one end connected between the main expansion device and the evaporator, and a second auxiliary expansion device. Second
Connection pipe is provided, the outlet pipe and one of the first and second connection pipes, the permeated refrigerant outlet pipe and the first
And a refrigeration system provided with a four-way valve that connects the other of the second connection pipes in a switchable manner.