JPH08136069A - Refrigerator using non-azeotrope refrigerant mixture - Google Patents

Abstract

PURPOSE: To control the cooling characteristics by cooling refrigerant mixture, separating and storing the component having high critical temperature, and forming a refrigerating cycle with the mixture refrigerant in which the component of low critical temperature is increased. CONSTITUTION: Non-azeotrope refrigerant mixture to be fed is separated into a vapor-phase component containing a component A having low critical temperature of an upper part in a vapor-liquid separator 6 and a liquid-phase component containing a component B having high critical temperature of a lower part. The component B is stored in the separator 6, the vapor-phase component containing the component A of the low critical temperature of the upper part is introduced into a main condenser 2b, condensed to be liquefied, pressure- reduced by a capillary tube 3, a low temperature is generated by an evaporator 4, and then sucked into a compressor 1 via an accumulator 5. The component B stored in the separator 6 can be returned to a refrigerant circuit via a pipeline (broken line) 9 or a pipeline (chain single-dashed line) 19 for connecting the separator 6 to the outlet of the evaporator 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus using a non-azeotropic refrigerant mixture, and more particularly to a refrigeration circuit using an HFC-based non-azeotropic refrigerant mixture which does not have a risk of depleting the ozone layer. The present invention relates to a refrigeration system capable of controlling the refrigeration characteristics by changing the composition ratio of the mixed refrigerant.

[0002]

2. Description of the Related Art Refrigeration systems using non-azeotropic refrigerant mixtures are
By changing the composition ratio of the refrigerant circulating in the refrigeration circuit, it is possible to control the refrigeration capacity and improve the performance. Conventionally, a refrigerating machine having a refrigerating circuit as shown in FIG. 2 has been proposed as a refrigerating machine which obtains a low temperature by one-stage compression using a non-azeotropic refrigerant mixture (refrigerator, Shunichi Tezuka, Kyoritsu Shuppan, 1965). ). The arrow indicates the flow of the refrigerant.

In FIG. 2, 1 is a compressor, 2 is a condenser, and 6
Is a gas-liquid separator connected to the outlet of the condenser, and the inflowing non-azeotropic refrigerant mixture contains, in the gas-liquid separator 6, a gas component containing a large amount of low boiling point components in the upper part and a large amount of high boiling point components in the lower part. Separated into liquid components. The liquid component in the lower portion is decompressed by the expansion device 7 to generate cold, and also passes through the heat exchanger 8 and the compressor 1
Inhaled. On the other hand, the gas components in the upper part of the gas-liquid separator 6 are condensed and liquefied in the heat exchanger 8, decompressed in the capillary tube 3 to generate a low temperature in the evaporator 4, and then sucked into the compressor 1 via the accumulator 5. It Compared with the refrigerant mixture circulating in the compressor 1, the low boiling point component flows more in the evaporator 4, so that a lower temperature can be obtained by one-stage compression, but the gas component separated in the gas-liquid separator 6 Since the liquid component and the liquid component can be separated only in the range of the concentration uniquely expressed in the one-stage equilibrium state of the saturated gas line and the saturated liquid line at the constant temperature shown in the temperature-concentration diagram of the non-azeotropic refrigerant mixture, The gas component above the gas-liquid separator 6 contains a large amount of high-boiling components, and as a result, the temperature level at which the temperature can be lowered is limited and limited.

In order to improve this drawback, a low temperature device (Japanese Unexamined Patent Publication (Kokai) No. 61-101757) in which a rectifying device is provided in place of the gas-liquid separator 6 to separate a low boiling point component and a high boiling point component, In place of the gas-liquid separator 6, a refrigerating apparatus in which a low boiling point component and a high boiling point component are separated by providing a functional film for facilitating the permeation of a specific refrigerant among a plurality of refrigerants (Japanese Patent Application Laid-Open No. Sho-6
No. 3-243662) has been proposed, but all of them have a drawback that the refrigeration circuit becomes complicated and the cost increases.

[0005]

The object of the present invention is to use a non-azeotropic refrigerant mixture, preferably an HFC-based non-azeotropic refrigerant mixture which does not pose a risk of depleting the ozone layer, depending on the purpose. It is an object of the present invention to provide a refrigeration system capable of controlling the cooling characteristics by changing the composition ratio of the refrigerant inside.

[0006]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in view of the above problems, a non-azeotropic refrigerant mixture containing a component having a higher critical temperature and a component having a lower critical temperature than that is used.
Cooling the refrigerant mixture to a specific temperature range, liquefying and separating a component having a high critical temperature and storing a predetermined amount, and configuring a refrigeration circuit as a mixed refrigerant in which a component ratio of a component having a low critical temperature is increased. The inventors have found that the above-mentioned problems can be solved by the above and have completed the present invention.

That is, the present invention comprises a main condenser for condensing and liquefying the refrigerant, a capillary tube, an evaporator for evaporating the liquefied refrigerant, an accumulator, and a compressor for compressing the evaporated and vaporized refrigerant and discharging it to the condenser. In a refrigeration system using a non-azeotropic refrigerant mixture containing a component having a higher critical temperature and a component having a lower critical temperature as a refrigerant compressed by a compressor, a sub-condenser and a gas are provided between the compressor and the main condenser. A liquid separator is provided, and in the sub-condenser, the refrigerant mixture is cooled to a temperature range lower than the critical temperature of the high critical temperature component and higher than the critical temperature of the low critical temperature component to liquefy the high critical temperature component. Then, the gas-liquid separator controlled in the temperature range is used to separate the gas-phase component and the liquid-phase component, and a predetermined amount of the liquid-phase component is stored in the gas-liquid separator. Over the ingredients and Condensing component relates refrigerating apparatus using a non-azeotropic refrigerant mixture, characterized in that it is designed to condensed and introduced into the main condenser.

[0008]

The gas pressure-volume curve is shown in FIG. At a temperature below the critical temperature Tc (T <Tc), the gas condenses due to compression to become a liquid, but at a temperature above the Tc (T> T).
In c) condensation does not occur when compressed. In order to liquefy the gas, it is necessary to cool it to Tc or lower. C indicates a critical point.

FIG. 4 shows the pressure-volume curves of the gas of component B having a high critical temperature and component A having a low critical temperature. (Tc) _B
Indicates the critical temperature of component B having a high critical temperature, (Tc) _B
The pressure-volume curve (dashed-dotted line) of the B component in FIG. 3 is shown, and C _B shows the critical point. The temperature T is (Tc) _A <
The pressure-volume curve (dashed line) of the B component for T <(Tc) _B is also shown. (Tc) _A shows the critical temperature of the component A having a low critical temperature, the pressure-volume curve (solid line) of the A component in (Tc) _A is shown, and C _A shows the critical point. A pressure-volume curve (solid line) of the A component when the temperature T ′ is T ′ <(Tc) _A is also shown.

In the present invention, a sub-condenser and a gas-liquid separator are provided between the compressor and the main condenser, and in the sub-condenser, the temperature is lower than the critical temperature (Tc) _{B of the} component B having a high critical temperature, and The refrigerant mixture is cooled to a temperature range (Tc) _A <T <(Tc) _B higher than the critical temperature (Tc) _A of the low critical temperature component. For example, when the refrigerant mixture in the state of point a in FIG. 4 is cooled to reach point b under the pressure-volume curve at (Tc) _B of component B, condensation and liquefaction of component B starts, and then to point c. Condensation liquefaction proceeds. On the other hand, the component _A does not condense and liquefy in a state where the temperature is (Tc) _A <T <(Tc) _B , and maintains the state of the gas phase.

After separating the gas-phase component A and the liquid-phase component B by a gas-liquid separator controlled in the temperature range (Tc) _A <T <(Tc) _B , the desired composition ratio is The component B is stored in a gas-liquid separator so as to obtain, and the component B and the component A in the gas phase, which exceed the storage amount, are introduced into the main condenser and the temperature T '<(T
c) _A refrigeration circuit is constructed so that it is cooled to _A and condensed and liquefied. As a result, the composition ratio of the non-azeotropic refrigerant mixture can be changed, and the cooling characteristics can be controlled by changing the storage amount. According to the present invention, a low temperature can be obtained efficiently and economically by one-stage compression using a non-azeotropic refrigerant mixture.

If the HFC-based non-azeotropic refrigerant mixture is used as the non-azeotropic refrigerant mixture, there is no danger of destroying the ozone layer.

The liquid phase components separated in the gas-liquid separator may be returned to the refrigeration circuit. Specifically, for example, a pipeline for returning from the gas-liquid separator to the outlet of the evaporator can be provided to return to the refrigeration circuit. Further, it is possible to provide a pipeline for returning the components of the liquid phase separated in the gas-liquid separator to the outlet of the evaporator after cooling the main condenser via the capillary tube and to return it to the refrigeration circuit.

In the present invention, the refrigerating machine oil is not particularly limited. Mineral oil-based lubricating oil, alkylbenzene-based lubricating oil, ester-based lubricating oil, ether-based lubricating oil, or a mixture thereof can be preferably used.

[0015]

EXAMPLES The contents of the present invention will be described more specifically below with reference to examples, but the present invention is not limited to these contents. FIG. 1 shows an example of a refrigerating circuit of the refrigerating apparatus of the present invention. In FIG. 1, 1 is a compressor, 2a is a sub-condenser, 6
Is a gas-liquid separator connected to the outlet of the sub-condenser 2a, and the inflowing non-azeotropic refrigerant mixture in the gas-liquid separator 6 has a gas phase component including a component A having a low critical temperature in the upper part and a critical component in the lower part. It is separated into a liquid phase component containing a high temperature component B. The lower liquid phase component B is stored in the gas-liquid separator 6, and the upper gas phase component including the component A having a low critical temperature is introduced into the main condenser 2b to be condensed and liquefied, and is decompressed and evaporated in the capillary tube 3. After a low temperature is generated in the container 4, it is sucked into the compressor 1 through the accumulator 5. The arrow indicates the flow of the refrigerant. The liquid phase component B stored in the gas-liquid separator 6 can be returned to the refrigeration circuit via a pipe line (shown by a broken line) 9 connecting the gas-liquid separator 6 and the outlet of the evaporator 4. Further, the liquid phase component B stored in the gas-liquid separator 6 cools the main condenser 2b from the gas-liquid separator 6 via the capillary tube 3 ', and then flows into the pipeline from the outlet of the evaporator 4. It can be returned to the refrigeration circuit via a connecting line (indicated by a chain line) 10.

As a component A having a low critical temperature, difluoromethane (HFC-32, R-32, boiling point -51.7 ° C., T
c = 78.4 ° C., critical pressure 5.83 MPa), 1,1,1,2-tetrafluoroethane (HFC-134a, R-134a. Component B having high critical temperature, boiling point −26.
5 ° C, Tc = 101.1 ° C, critical pressure 4.06 MPa)
Fig. 1 shows a non-azeotropic refrigerant mixture made by mixing the two using
Used as a refrigerant for the refrigeration circuit of No. 2, and the non-azeotropic refrigerant mixture was cooled in the sub-condenser 2a to 78.4 ° C. to 101.1 ° C. As a result, HFC-134a was liquefied and HFC-134a
32 was in a vapor phase. A predetermined amount of liquefied HFC-134a separated in the gas-liquid separator 6 is stored in the gas-liquid separator 6, and HFC-134a and gas-phase HFC-32 that exceed the storage amount are stored in the main condenser 2b. As a result of introducing the gas into a condensate and liquefying it and constructing a refrigeration circuit, the refrigeration capacity could be improved.

[0017]

In the refrigerating apparatus using the non-azeotropic refrigerant mixture of the present invention, the refrigerating capacity can be easily controlled and the performance can be improved by changing the composition ratio of the refrigerant circulating in the refrigerating circuit. it can. If an HFC-based non-azeotropic refrigerant mixture is used as the non-azeotropic refrigerant mixture, there is no danger of destroying the ozone layer. The refrigerating apparatus of the present invention is economical because it has a simple structure, and is highly effective and has high industrial utility value.

[Brief description of drawings]

FIG. 1 is an example of a refrigeration circuit of a refrigeration apparatus of the present invention.

FIG. 2 is an example of a refrigeration circuit of a conventional refrigeration system.

FIG. 3 is a gas pressure-volume curve.

FIG. 4 is a pressure-volume curve of another gas.

[Explanation of symbols]

 1 Compressor 2 Condenser 2a Sub-condenser 2b Main condenser 3, 3'Capillary tube 4 Evaporator 5 Accumulator 6 Gas-liquid separator 7 Throttling device 8 Heat exchanger 9, 10 Pipe line

Claims (4)

[Claims] 1. A main condenser for condensing and liquefying a refrigerant, a capillary tube, an evaporator for evaporating a liquefied refrigerant, an accumulator, a compressor for compressing the evaporated vaporized refrigerant and discharging it to a condenser, and the like. In a refrigerating apparatus using a non-azeotropic refrigerant mixture containing a component having a high critical temperature and a component having a lower critical temperature as the refrigerant to be used, a sub-condenser and a gas-liquid separator are provided between the compressor and the main condenser. Provided,
In the sub-condenser, the refrigerant mixture is cooled to a temperature range below the critical temperature of the high critical temperature component and above the critical temperature of the low critical temperature component to liquefy the high critical temperature component and then to the temperature range. The gas-liquid separator controlled to separate the gas-phase component and the liquid-phase component, and the predetermined amount of the liquid-phase component is stored in the gas-liquid separator. A refrigeration system using a non-azeotropic refrigerant mixture, characterized in that the condensed component is designed to be introduced into a main condenser and condensed and liquefied. 2. The refrigerating apparatus according to claim 1, wherein the refrigerant is an HFC-based non-azeotropic refrigerant mixture. 3. A pipe for returning the liquid phase component separated in the gas-liquid separator to the outlet of the evaporator, or a capillary tube for the liquid phase component separated in the gas-liquid separator. The refrigerating apparatus according to claim 1 or 2, further comprising a pipe line that returns the outlet of the evaporator after cooling the main condenser via the evaporator. 4. The refrigerating apparatus according to claim 1, wherein the refrigerating machine oil is a mineral oil type lubricating oil, an alkylbenzene type lubricating oil, an ester type lubricating oil, an ether type lubricating oil or a mixture thereof.