JP3480205B2 - 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 an air conditioner using a non-azeotropic mixed refrigerant, and in particular, a part of the high temperature high pressure liquid refrigerant condensed in a condenser is branched and the branched refrigerant is expanded. It is suitable for an air conditioner provided with a supercooler for exchanging heat between the low-temperature refrigerant and the high-temperature high-pressure liquid refrigerant in the main refrigeration cycle.

[0002]

2. Description of the Related Art Conventionally, as an example of supercooling a high-temperature high-pressure liquid refrigerant in a main refrigeration cycle to improve the cooling capacity, for example, the one disclosed in Japanese Patent Laid-Open No. 287059/1990 is known.

In the refrigerating cycle according to the present prior art, the refrigerant heat-exchanged by the condenser is branched into two directions, one of which is passed through the subcooler to the evaporator which is the main cycle side. The other is expanded by the expansion valve for the subcooler and sent to the subcooler.

[0004]

The above-mentioned prior art is not designed in consideration of the fact that the respective component refrigerants have different boiling points, which is a characteristic of the non-azeotropic mixed refrigerant considered as an alternative refrigerant. Therefore, when using a non-azeotropic mixed refrigerant,
The composition ratio of each component refrigerant in the refrigerant differs depending on the pressure and temperature of the non-azeotropic mixed refrigerant even during the refrigeration cycle, and the capacity on the evaporator side is not sufficient.Pressure loss when the piping between the indoor and outdoor units is long distance piping. Causes a problem that

An object of the present invention is to improve the capacity of a refrigeration cycle using a non-azeotropic mixed refrigerant, and even if the piping between the indoor unit and the outdoor unit is a long distance piping, the capacity loss due to pressure loss is small. Is provided.

[0006]

SUMMARY OF THE INVENTION The present invention is a compressor, condenser.
Cooling system in which the reactor, decompression device, and evaporator are sequentially connected by piping.
Has a freeze cycle and uses a non-azeotropic mixed refrigerant as the working refrigerant
In the installed air conditioner, it is connected to the downstream side of the condenser.
Excess refrigerant is stored and the concentration of high boiling point refrigerant from the working refrigerant is
Refrigerant quantity regulator that branches high refrigerant, condenser and refrigerant quantity regulator
It is provided between the outlet and the outlet of the condenser and the outlet of the compressor.
Condensing pressure control valve installed in each pipe
And the concentration of high boiling point refrigerant branched by the refrigerant amount controller is high
Excessive heat exchange between the refrigerant and the refrigerant of the other main refrigeration cycle
The refrigerant of the main refrigeration cycle from the cooler and the refrigerant amount controller
A main decompressor leading to the evaporator after expansion,
It is a thing.

Since the excess refrigerant is stored in the mixed refrigerant state in the refrigerant amount controller connected to the downstream side of the condenser,
Regardless of the length of the pipe between the indoor unit and the outdoor unit, the working refrigerant flowing through the refrigeration cycle can be adjusted, and the refrigerant having a high boiling point refrigerant concentration can be branched. Furthermore, the refrigerant having the highest concentration of the refrigerant having the highest boiling point in composition ratio is sent to the subcooler, and conversely, the refrigerant having the highest concentration of the refrigerant having the lowest boiling point is sent to the main refrigeration cycle side.

For example, among the component refrigerants of the mixed refrigerant, R32 has a low boiling point and R134a has a high boiling point, but R32 is physically more energy efficient than R134a. Therefore, the mixed refrigerant having a high efficient refrigerant concentration flows in the main refrigeration cycle, and the capacity of the evaporator is increased by heat exchange by the subcooler, and the high boiling refrigerant concentration is high in the subcooler. Therefore, the evaporation temperature does not become low, resulting in a small loss. Further, the refrigerant having a high R32 refrigerant concentration, which has a low boiling point, has a specific volume smaller by about several percent in a low-pressure gas state than a mixed refrigerant of a normal composition, and when the piping between the indoor and outdoor units becomes a long-distance piping. The pressure loss in the low-pressure gas pipe, which is a problem, is reduced.

[0009]

[0010]

[0011]

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
This will be described with reference to Nos. 3 to 3. FIG. 1 is a block diagram showing a basic configuration of a refrigeration cycle of an air conditioner according to an embodiment, FIG. 2 is an enthalpy vs. pressure diagram of a mixed refrigerant R407c, and FIG. 3 is an isobaric gas of R32 in a mixed refrigerant R407c. It is an equilibrium curve diagram.

The air conditioner shown in FIG.
The condenser 2, the decompression device 7, and the evaporator 5 are sequentially connected to form a refrigeration cycle, which includes a condensation pressure adjusting valve 8, a refrigerant amount adjuster 3, and a supercooler 4. This air conditioner uses a non-azeotropic mixed refrigerant, and the non-azeotropic mixed refrigerant used is one produced by mixing several kinds of refrigerants having different physical properties such as boiling point and specific volume. R407c can be used. R407c is R as a component refrigerant
32 is 23%, R125 is 25%, R134a is 52%
It is a three-component mixed refrigerant having a weight composition ratio of.

In FIG. 1, the condensing pressure adjusting valve 8 is installed in the pipes provided at the outlet of the condenser 2 and the outlet of the compressor 1, respectively, and the refrigerant amount adjusting device 3 is provided with the condensing pressure adjusting valve 8.
Is connected to the downstream side of. The subcooler 4 is connected to the pipes from the lower outlet a and the upper outlet b of the refrigerant amount regulator 3. A pressure reducing device 6 is provided between the lower outlet a of the refrigerant amount adjuster 3 and the supercooler 4.

The liquid refrigerant branched from the lower outlet a of the refrigerant amount adjuster 3 is expanded by the pressure reducing device 6 to a low pressure and low temperature, and then sent to the subcooler 4. On the other hand, the gas-liquid mixed refrigerant of the main refrigeration cycle flowing out from the upper outlet b of the refrigerant amount adjuster 3 is supercooled in the subcooler 4 by the liquid refrigerant having a low pressure and low temperature, and further, the main decompression device 7 and the evaporation device. It is returned to the compressor 1 via the container 5.

In the refrigerant amount controller 3, the refrigerant is separated into a lower liquid portion and an upper gas portion, and the liquid portion has the highest boiling point among the component refrigerants of the mixed refrigerant and the other component refrigerants. Many are included because they are more easily condensed. Therefore, the pipe leading to the decompression device 6 in the branch circuit to the subcooler 4 is taken out from the lower portion or the bottom portion of the refrigerant amount regulator 3, so that the high-temperature high-pressure liquid refrigerant is branched.

The refrigerant branched as a liquid refrigerant from the lower outlet a of the refrigerant amount adjuster 3 exchanges heat with the gas-liquid mixed refrigerant of the main refrigeration cycle in the subcooler 4 and is then connected to the compressor 1 side. It returns to the compressor 1 through the bypass pipe c. Therefore, the branched refrigerant does not participate in heat exchange in the evaporator 5. Next, the characteristics of the refrigeration cycle of this embodiment will be described with reference to FIGS. 2 and 3. In FIG. 3, the horizontal axis represents the weight composition ratio of R32 in R407c, and the vertical axis represents the temperature.
When the weight composition ratio of R32 is X0, the temperature lowers to T3.
Then, liquefaction of R32 starts, and R407c becomes a two-phase state of liquid and gas, and when temperature becomes T0, it is completely liquefied, and R407c indicates that only liquid phase is obtained.

Refrigerant discharged from the compressor 1 (2 in FIG. 2)
Is condensed into high pressure liquid refrigerant in the condenser 2. Here, assuming that the temperature of the refrigerant amount controller is T1 (3 in FIG. 2), the weight composition ratio of R32 in the liquid of R407c is X1 from FIG. 3, which is smaller than X0 at the standard composition,
Therefore, conversely, the weight composition ratio of R134a in the liquid of R407c becomes large. A part of this liquid is branched as a liquid refrigerant from the lower outlet a of the refrigerant amount controller 3.

Then, a liquid refrigerant having a high concentration of R134a is sent to the branch circuit side and a refrigerant having a high concentration of R32 is sent to the main circuit side, and the subcooler 4 exchanges heat with each other. As a result, the refrigerant on the main circuit side is supercooled by the supercooler 4 to the state of 6 in FIG. 2, expanded by the decompression device 7, and then evaporated by the evaporator 5 from 8 to 9 in FIG. ,
The low-pressure gas pipe changes from 9 to 10 in FIG. 2 and returns to the outdoor unit. Further, the refrigerant on the side of the branch circuit is depressurized to 4 to 5 in FIG. 2 by the pressure reducing device 6 and brought to the state of 5 to 1 in FIG. 2 by the supercooler 4, and is mixed with the refrigerant in the main circuit again.

By the above refrigeration cycle, the refrigerant having a high concentration of R32 and having a high energy efficiency is sent to the evaporator 5, so that the evaporator 5 is different from the standard composition R407c.
Side cooling capacity increases. In the low pressure gas pipe,
Since the specific volume of the refrigerant having a higher R32 concentration is smaller, the pressure loss is smaller, and it is possible to reduce the deterioration of the performance even if the piping between the indoor unit and the outdoor unit has a long distance.

Another embodiment will be described with reference to FIG. FIG. 4 is a block diagram showing the basic configuration of the refrigeration cycle, and is the same as that of FIG. 1 except that the installation method of the refrigerant amount adjuster (liquid refrigerant separator) 3 is different. In FIG. 4, the liquid-refrigerant separator 3 is installed at the end of a pipe 3a branched from an intermediate pipe between the inlet and the outlet of the condenser 2, and the refrigerant taken out from the outlet 3a is a gas-liquid mixed refrigerant / liquid. The gas-liquid mixed refrigerant separated into the refrigerant is returned to the condenser 2 through the pipe 3b.

One of the liquid refrigerants is heat-exchanged through the pipe 3c, the pressure reducing device 6 and the supercooler 4, and is returned to the compressor 1 by the bypass pipe 3e connected to the compressor 1 side. Further, the refrigerant flowing out from the regular outlet 3d of the condenser 2 is heat-exchanged in the supercooler 4 to be cooled, and then returned to the compressor 1 via the evaporator 5.

In the present embodiment, the liquid-refrigerant separator 3 separates the liquid-refrigerant from the liquid-gas refrigerant in the condenser 2 during the condensation process. That is, since the liquid refrigerant can be separated at a temperature higher than the temperature T1 as compared with the liquid refrigerant separation in the refrigerant amount adjuster 3 described above, the weight composition ratio of R32 in the liquid of R407c is equal to that of the above-described embodiment. The composition ratio is lower than that of X1 in the above-mentioned form, and conversely, the weight composition ratio of R134a is high.

From the above, it is possible to further increase the capacity of the evaporator 5 side and reduce the pressure loss in the piping between the indoor and outdoor units.

[0025]

According to the present invention, in a refrigeration cycle using a non-azeotropic mixed refrigerant, a mixed refrigerant having a high efficient refrigerant concentration flows into the main refrigeration cycle, and a refrigerant having a high high boiling point refrigerant concentration is overheated. Since heat is exchanged by the cooler, the capacity on the evaporator side rises, and the loss in the subcooler is small, so the capacity is improved, and even if the piping between the indoor and outdoor units becomes a long distance piping, the capacity due to pressure loss An air conditioner with less deterioration can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a refrigeration cycle of an air conditioner according to an embodiment.

FIG. 2 is an enthalpy versus pressure diagram of a mixed refrigerant R407c.

FIG. 3 is an isobaric vapor-liquid equilibrium curve diagram of R32 in a mixed refrigerant R407c.

FIG. 4 is a block diagram showing a basic configuration of a refrigeration cycle of an air conditioner according to another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Condenser, 3 ... Refrigerant amount regulator (liquid refrigerant separator), 4 ... Supercooler, 5 ... Evaporator, 6 ... Decompression device, 7
Decompression device 2, 8 ... Condensing pressure adjusting valve, a ... Refrigerant amount controller lower outlet, b ... Refrigerant controller upper outlet, c ... Bypass pipe, 3e ... Bypass pipe.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-136069 (JP, A) JP-A-7-103588 (JP, A) JP-A-8-327181 (JP, A) Actual development 63- 125753 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 1/00 395 F25B 1/00 385

Claims (2)

(57) [Claims] 1. An air conditioner having a refrigeration cycle in which a compressor, a condenser, a pressure reducing device, and an evaporator are sequentially connected by piping, and a non-azeotropic mixed refrigerant is used as a working refrigerant. Is connected to the downstream side to store excess refrigerant, a refrigerant amount controller for branching the refrigerant having a high concentration of high boiling point refrigerant from the working refrigerant , and provided between the condenser and the refrigerant amount controller,
It is provided at the outlet of the condenser and the outlet of the compressor, respectively.
A condensing pressure adjusting valve installed in the pipe, a supercooler for exchanging heat between the refrigerant having a high concentration of the high boiling point refrigerant branched by the refrigerant amount controller and the refrigerant of the other main refrigeration cycle, and the refrigerant. An air conditioner comprising: a main decompression device that expands the refrigerant of the main refrigeration cycle from the quantity regulator and then guides it to the evaporator. 2. The air conditioner according to claim 1, wherein a pipe is provided below the refrigerant amount controller to branch the working refrigerant.