WO2020040471A1

WO2020040471A1 - Freezer

Info

Publication number: WO2020040471A1
Application number: PCT/KR2019/010284
Authority: WO
Inventors: 윤상국
Original assignee: 한국해양대학교 산학협력단
Priority date: 2018-08-22
Filing date: 2019-08-13
Publication date: 2020-02-27
Also published as: KR20200022116A

Abstract

A freezer is disclosed. A freezer according to an embodiment comprises: a compressor configured to discharge a refrigerant in the gas state; a condenser configured to cool and liquefy the refrigerant discharged from the compressor; a liquid-gas separator configured to primarily expand the refrigerant liquefied in the condenser to an intermediate pressure to collect the refrigerant in the liquid state and the gas state; and an evaporator which cools a predetermined space as the refrigerant in the liquid state flows from the liquid-gas separator into the evaporator and then is secondarily expanded to a final pressure and thus absorbs heat and is gasified, and which guides the refrigerant in the gas state in the liquid-gas separator to the compressor.

Description

Freezer

The following embodiments relate to a refrigerator, and more particularly, to a refrigerator in which the expansion of the refrigerant is performed in two stages.

The refrigerator refers to a device that reduces the temperature of one side by taking heat from one side and transferring it to the other side.

Hereinafter, a refrigerator will be described as a representative example of a refrigerator. The refrigerator described below may be used to mean a refrigerator.

1 is a view schematically showing the structure of a conventional refrigerator.

Referring to FIG. 1, the conventional refrigerator 10 may include a compressor 11, a condenser 12, a precooling pipe 13, an expansion device 14, and an evaporator 15, according to an embodiment. It may further include a receiver.

The compressor 11 compresses the low-temperature, low-pressure gaseous refrigerant provided by the evaporator 15 to a high temperature and high pressure, and delivers the refrigerant to the condenser 12, and the condenser 12 compresses the high-temperature, high-pressure gas in the compressor 11. The refrigerant is condensed to be a liquid refrigerant by heat exchange with external air or water, and transferred to the receiver, and the receiver temporarily stores the liquid refrigerant condensed at high temperature and high pressure in the condenser 12. The expansion device 14 rapidly expands the high-temperature, high-pressure liquid refrigerant supplied from the receiver to transfer the low-temperature low-pressure refrigerant to the evaporator 15, and the evaporator 15 is the low-temperature low pressure supplied from the expansion device 14. The refrigerant of the gas is evaporated by heat exchange with the heat exchange medium such as external air and water to evaporate to generate a gaseous refrigerant having a low temperature and low pressure, and then transferred to the compressor 11.

The conventional refrigerator 10 is a mixture of liquid and gas while the condensed high pressure liquid refrigerant of the condenser 12 drops to a low pressure, at which time gas is generated about 30%. As the refrigerant liquid (ie, the liquid refrigerant in the liquid state) increases after expansion, the freezing capacity of the evaporator 15 increases, and the generated gas does not play a role of freezing. Both the liquid and gas expanded at low pressure are vaporized in the evaporator 15 and then recompressed to high pressure using power in the compressor 11.

Korean Laid-Open Patent Publication No. 2003-0080535 describes a technology related to such an intermediate heat exchange refrigeration apparatus.

Embodiments describe a refrigerator having two stages of expansion of a refrigerant, and more particularly, provides a technique in which the medium pressure gas inside the medium expansion liquid separator flows directly into the compressor without flowing to the evaporator.

Embodiments of the present invention collect liquid and gaseous refrigerant generated in a liquid separator by expanding the high-pressure liquid refrigerant in a condenser at an intermediate pressure, and the liquid refrigerant, which functions as a freezer, expands to a final pressure and then flows into an evaporator. In the present invention, a medium-pressure gaseous refrigerant in a liquid separator that is independent of the refrigeration function is sent directly to the compressor without being introduced into the evaporator, thereby providing a refrigerator that compresses the medium pressure to a high pressure.

In one embodiment, a refrigerator includes: a compressor configured to discharge a refrigerant in a gaseous state; A condenser for cooling and liquefying the refrigerant discharged from the compressor; A first expansion device for expanding the refrigerant liquefied in the condenser; A liquid separator for collecting the refrigerant in a liquid state and a gas state passing through the first expansion device; A second expansion device for expanding and guiding the refrigerant in a liquid state discharged from the liquid separator to the evaporator; And an evaporator that cools a predetermined space as the refrigerant in a liquid state passing through the second expansion device sucks heat and vaporizes, and guides the refrigerant in a gas state to the compressor.

Here, the liquid separator may guide the refrigerant in a liquid state performing a freezing function to the evaporator, and guide the refrigerant in a gaseous state irrelevant to the freezing function to the compressor.

The compressor may include a refrigerant in a first gas state vaporized by flowing into the evaporator after the liquid refrigerant expands to a final pressure from the liquid separator, and a refrigerant in a second gas state moving from the liquid separator to the compressor. Inlet can be recompressed.

The refrigerant in the second gas state may be a relatively high pressure than the refrigerant in the first gas state, and may be in an intermediate pressure state having a relatively low pressure than when recompressed in the compressor.

The apparatus may further include a precooling pipe configured to subcool the liquid refrigerant discharged from the condenser using the refrigerant in a gas state discharged from the evaporator.

After first expanding the refrigerant liquefied in the condenser to guide the liquid separator, and secondly expands the refrigerant in the liquid state discharged from the liquid separator to guide the evaporator to expand the refrigerant in two stages. .

According to the embodiments, the liquid refrigerant of the high pressure liquid state of the condenser is expanded to an intermediate pressure, and the liquid and gaseous refrigerants generated by the liquid separator are collected in the liquid separator. And the gaseous refrigerant in the medium pressure of the liquid separator, which is not related to the refrigeration function, is sent directly to the compressor without entering the evaporator, thereby providing a refrigerator which can compress the medium pressure to a high pressure and greatly reduce the amount of compression power. have.

In addition, it provides the effect of increasing the low-temperature heat, that is, the freezing capacity provided by the liquid entering the evaporator.

According to the embodiments, only 100% of the liquid in the liquid separator of the liquid separator may be expanded to a low pressure, which is the final pressure, and then introduced into the evaporator, thereby providing a refrigerator having an effect of increasing evaporator efficiency and reducing specifications.

1 is a view schematically showing the structure of a conventional refrigerator.

2 is a view schematically showing the structure of a refrigerator according to one embodiment.

3 is a view for explaining a change in efficiency according to the intermediate pressure according to an embodiment.

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings. However, the described embodiments may be modified in many different forms, and the scope of the present invention is not limited to the embodiments described below. In addition, various embodiments are provided to more fully describe the present invention to those skilled in the art. Shapes and sizes of elements in the drawings may be exaggerated for clarity.

All freezers, including refrigerators, produce about 30% of their gas during expansion. At this time, the more gas after expansion, the lower the freezing capacity of the evaporator and the generated gas has no freezing function. Liquid and gas are introduced into the evaporator so that only the liquid is converted into gas, which absorbs external heat to provide a low temperature. The liquid and gas expanded at low pressure are both vaporized in the evaporator and then recompressed by both consuming power at high pressure in the compressor.

Refrigerator efficiency, ie, COP (Coefficient Of Performance), is the amount of heat absorbed by the evaporator divided by the power required for the compressor. Therefore, there is a need for a method that can increase efficiency by increasing evaporator suction heat or lowering compressor power.

The following embodiments are directed to a refrigerator having two stages of expansion of a refrigerant, and provides a refrigerator in which the medium pressure gas inside the liquid separator of the intermediate expansion flows directly into the compressor without flowing to the evaporator. More specifically, embodiments of the present invention collect liquid and gaseous refrigerant generated in a liquid separator by expanding the high pressure liquid refrigerant in a condenser at an intermediate pressure, and the liquid refrigerant having a refrigerating function at a final pressure at low pressure. After expansion, it is introduced into the evaporator, and the gaseous refrigerant in the medium pressure of the liquid separator, which is not related to the freezing function, is sent directly to the compressor without being introduced into the evaporator, thereby providing a freezer which increases the evaporator suction calories and compresses the medium pressure to a high pressure. can do.

Referring to FIG. 2, the refrigerator 100 according to an embodiment includes a compressor 110, a condenser 120, a first expansion device 140, a liquid separator 150, a second expansion device 160, and an evaporator ( 170). According to an embodiment, the refrigerator 100 may further include a precooling pipe 130. It is also possible to further include a receiver according to the embodiment.

The compressor 110 sucks the refrigerant as a working fluid, compresses the refrigerant, and discharges the compressed refrigerant. The compressor 110 may discharge the refrigerant in a gaseous state.

The condenser 120 may cool and liquefy the refrigerant by condensing the refrigerant discharged from the compressor 110.

The first expansion device 140 may expand the liquid liquefied in the condenser 120 to lower the pressure, and guide the liquid expansion separator 150 after expansion. At this time, the refrigerant may be first expanded at an intermediate pressure by the first expansion device 140. The first expansion device 140 may be made of an expansion valve.

The liquid separator 150 may expand the refrigerant liquefied in the condenser 120 to collect the refrigerant in a liquid state and a gas state. In particular, the liquid separator 150 guides the refrigerant in the liquid state performing the refrigerating function to the evaporator 170 after further expansion, and immediately passes the refrigerant in the gas state irrelevant to the refrigeration function without passing through the evaporator 170. Can be guided.

The second expansion device 160 may lower the pressure by expanding the liquid refrigerant discharged from the liquid separator 150 and may guide the evaporator 170 after expansion. Here, the second expansion device 160 may be formed of an expansion valve.

The evaporator 170 cools a predetermined space as the liquid refrigerant flows in from the liquid separator 150, sucks heat, and vaporizes the gas, and guides the refrigerant in the gas state to the compressor 110.

Here, the compressor 110 moves from the liquid separator 150 to the compressor 110 in the first gas state vaporized with the refrigerant a in a vaporized state by flowing into the evaporator 170 and from the liquid separator 150 to the compressor 110. The refrigerant b in the second gas state may be introduced and recompressed. At this time, the refrigerant (b) in the second gas state may be in a relatively high pressure than the refrigerant (a) in the first gas state, and may be in an intermediate pressure state which is relatively low pressure than when recompressed in the compressor (110).

As such, the medium pressure gas refrigerant of the liquid separator 150 irrelevant to the freezing function is directly sent to the compressor 110 without being introduced into the evaporator 170, thereby compressing the medium pressure to a high pressure.

Meanwhile, the liquid refrigerant in the condenser 120 may be subcooled with the cool gas refrigerant exiting the evaporator 150. This may be referred to as a precooling pipe 130 or a precooling pipe function, and the amount of liquid generated during expansion may be increased through the precooling pipe 130 or the precooling pipe function.

In other words, the refrigerator 100 according to an embodiment may further include a pre-cooling pipe 130, the pre-cooling pipe 130 from the condenser 120 by using the refrigerant in the gas state discharged from the evaporator 170. The discharged liquid refrigerant can be subcooled.

Accordingly, the low pressure first gaseous state a and the medium pressure second gaseous state b may be mixed and introduced into the compressor 110. As such, the refrigerator 100 according to an embodiment first expands the liquefied refrigerant in the condenser 120 to guide the liquid separator 150, and then stores the refrigerant in the liquid state discharged from the liquid separator 150. The expansion may be guided to the evaporator 170 to expand the refrigerant in two stages.

According to embodiments, the efficiency of various refrigerators such as a refrigerator and an air conditioner may be greatly improved. Interpreting the process according to these embodiments is as follows.

In the following, as an example of a refrigerator, a process of a refrigerator will be compared.

As described with reference to FIG. 1, the conventional refrigerator 10 becomes a mixture of liquid and gas while the condensed high pressure liquid refrigerant of the condenser 12 drops to a low pressure, and the more refrigerant in the liquid state after expansion, the evaporator ( The freezing capacity of 15) is increased, and the gas produced at this time does not play a freezing role. The liquid and gaseous refrigerant expanded at low pressure are both vaporized in the evaporator 15 and then recompressed to high pressure using power in the compressor 11.

Process analysis and COP of the refrigerator to which the conventional refrigerant R134a is applied may be expressed as follows.

TABLE 1

COP = Qe / W = m (h4-h3) / m (h6- h5)

= (383.45-248.99) / (440.18-390.87)

= 134.46 / 49.31

= 2.7268

Thus, it can be seen that the COP of the conventional refrigerator is approximately 2.7268. Where m is the mass flow of refrigerant per hour (kg / h) and the same mass flows through the evaporator and the compressor.

As described above with reference to FIG. 2, the refrigerator 100 according to the exemplary embodiment has a high-pressure liquid refrigerant of the condenser 120 pre-cooled in the precooling pipe 130, and then, at the first expansion device 140, a medium pressure. It may be expanded and collected in the liquid separator 150. At this time, the gaseous refrigerant (b) of the intermediate pressure of the liquid separator 150 may flow directly into the compressor 110 without going to the evaporator 170.

Only the liquid refrigerant in the liquid and gaseous refrigerants of the liquid separator 150 may be introduced into the evaporator 170 at low temperature while being finally expanded by the second expansion device 160 to be vaporized. The vaporized low pressure cool gas coolant may partially increase the temperature of the liquid coolant while lowering the temperature of the liquid coolant condensed by heat exchange in the precooling pipe 130.

Thereafter, the low-pressure gaseous refrigerant a may be mixed with the medium-pressure gaseous refrigerant b and then introduced into the compressor 110.

Process analysis and COP under the same conditions of the refrigerator according to this embodiment can be expressed as follows.

TABLE 2

COP = Qe / W = m4 (h6-h5) / (m3 + m4) (h10- h9)

= (0.85219) (383.45-221.51) / (1) (433.53-394.42)

= 138.0 / 39.1096

= 3.528

As an example the median pressure is 5 bar with a COP of approximately 3.528.

Comparing the efficiency of the conventional refrigerator and the refrigerator according to the present embodiment, the freezing capacity of the evaporator is improved by 2.6% to 138 / 134.46, and the compression work is about 20.7% to 39.1 / 49.31.

The efficiency increase rate of the refrigerator according to the present embodiment is 3.5386 / 2.7268, it can be seen that the efficiency is improved by about 30%.

As such, the refrigerator according to the present exemplary embodiment may expand the high pressure refrigerant liquid in two stages. At this time, the medium-pressure gas inside the medium-expanded liquid separator does not flow to the evaporator and flows into the compressor, whereby the amount of compression power is greatly reduced.

That is, in the case of the conventional refrigerator, both the liquid and the gas generated after expansion to the low pressure, which is the pressure of the evaporator, are evaporated while flowing to the evaporator, and then recompressed in the compressor, thereby increasing the power demand of the compressor.

In addition, the refrigerator according to the present embodiment may be introduced into the evaporator after only 100% of the liquid of the liquid separator of the liquid separator is expanded to the final pressure low pressure.

The refrigerator according to the present embodiment is different from the conventional refrigerator in that the expansion device and the liquid separator are added, but there is an effect of increasing the evaporator efficiency and reducing the size.

Referring to FIG. 3, the efficiency change according to the middle pressure of the refrigerator refrigerant R134a is shown, and the COP according to the expansion middle pressure is illustrated.

When expanding at a high pressure of 10.166 bar, the COP increases with an increase in the intermediate pressure, up to 30% at about 5 bar. That is, at about 5 bar, the COP has a maximum value.

It decreases again after the maximum value of COP, and becomes the same as the conventional efficiency when the conventional single expansion pressure of 1.066 bar is reached.

As such, it can be seen that the COP of the refrigerator is increased by two stage expansion. At this time, the value of COP may vary depending on the type of refrigerant.

As described above, according to the embodiments, the liquid refrigerant in the high pressure liquid state of the condenser is expanded to an intermediate pressure, and the liquid and gaseous refrigerants collected in the liquid separator are collected, and the liquid refrigerant having a freezing function flows into the evaporator. The medium pressure gas refrigerant of the liquid separator, which is not related to the refrigeration function, is sent directly to the compressor without entering the evaporator, thereby compressing the medium pressure to a high pressure, which greatly reduces the amount of compression power and increases the evaporator's evaporation capacity. Can be. That is, the low-temperature heat provided by the liquid flowing into the evaporator is increased to improve the freezing capacity.

When a component is referred to as being "connected" or "connected" to another component, the component may be directly connected to or connected to the other component, but another component may be present in between. It should be understood that. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

In addition, the terms “… unit”, “… module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software.

In addition, the components of the embodiments described with reference to the drawings are not limited to the corresponding embodiments, and may be implemented to be included in other embodiments within the scope of the technical idea of the present invention. Although the description is omitted, it is obvious that a plurality of embodiments may be reimplemented into one integrated embodiment.

In addition, in the description with reference to the accompanying drawings, the same components regardless of reference numerals will be given the same or related reference numerals and redundant description thereof will be omitted. In the following description of the present invention, when it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Although the embodiments have been described by the limited embodiments and the drawings as described above, various modifications and variations are possible to those skilled in the art from the above description. For example, the described techniques may be performed in a different order than the described method, and / or components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different form than the described method, or other components. Or, even if replaced or substituted by equivalents, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims

A compressor for discharging a gaseous refrigerant;

A condenser for cooling and liquefying the refrigerant discharged from the compressor;

A first expansion device for expanding the refrigerant liquefied in the condenser;

A liquid separator for collecting the refrigerant in a liquid state and a gas state passing through the first expansion device;

A second expansion device for expanding and guiding the refrigerant in a liquid state discharged from the liquid separator to the evaporator; And

The evaporator which cools a predetermined space as the refrigerant in the liquid state passing through the second expansion device sucks heat and vaporizes, and guides the refrigerant in the gas state to the compressor.

Including, a freezer.
The method of claim 1,

The compressor,

Recompressing and introducing a refrigerant in a first gas state vaporized by flowing into the evaporator from the liquid separator and a refrigerant in a second gas state moving from the liquid separator to the compressor

Characterized in that, the freezer.
The method of claim 2,

The refrigerant in the second gas state,

Relatively high pressure than the refrigerant in the first gas state, a relatively low pressure medium pressure state than when recompression in the compressor

Characterized in that, the freezer.
The method of claim 1,

Primary expansion of the refrigerant liquefied in the condenser to guide the liquid separator; second expansion of the refrigerant in a liquid state discharged from the liquid separator to guide the evaporator to expand the refrigerant in two stages;

Including, a freezer.