CN113758039B - Natural working medium CO2Compression-supersonic speed two-phase expansion composite refrigerating system and refrigerator - Google Patents

Abstract

The invention provides a natural working medium CO₂A compression-supersonic speed two-phase expansion composite refrigerating system and a refrigerating machine comprise a supersonic speed two-phase expander and a circulating loop, wherein the supersonic speed two-phase expander comprises an inlet side, a gas outlet side and a liquid outlet side; the circulating loop comprises a first circulating pipeline communicated with the air outlet side, a second circulating pipeline communicated with the liquid outlet side and a third circulating pipeline formed by converging the first circulating pipeline and the second circulating pipeline, and the third circulating pipeline is communicated with the inlet side; an evaporator is arranged on either the second circulation pipeline or the third circulation pipeline, the outlet end of the evaporator is communicated with the third circulation pipeline, and a gas cooler is arranged on the third circulation pipeline to cool the gaseous refrigeration working medium flowing out of the first circulation pipeline and the second circulation pipeline. By the mode, the refrigeration system disclosed by the invention can achieve the beneficial effects of high refrigeration efficiency, environment-friendly and safe working medium.

Description

Natural working medium CO2 compression-supersonic two-phase expansion composite refrigeration system and refrigerator

technical field

The invention relates to the technical field of refrigeration, in particular to a natural working fluid _CO2 compression-supersonic two-phase expansion composite refrigeration system and a refrigerator.

Background technique

The sustainable development of energy and environment has become the focus of common attention all over the world. With the rapid development of my country's economy and society, there are more and more applications of low temperature, refrigeration and heat pump products. Low temperature and refrigeration technology has improved people's quality of life, but the environmental problems caused by leakage of various refrigerants are also becoming more and more serious. Popularization and application Environmentally friendly refrigerants are of great significance for energy saving and emission reduction and promoting sustainable social development. At present, the development history of refrigerants is mainly divided into four stages: the first-generation refrigerants are represented by natural working fluids such as CO ₂ and ethers; as the second-generation synthetic refrigerants chlorofluorocarbons (CFCs) and hydrogen With the development of chlorofluorocarbons (HCFCs), natural working fluids have been gradually eliminated because the system efficiency cannot be compared with artificial synthetic working fluids, but the second-generation refrigerants have higher Ozone Depletion Potential (ODP) It has also withdrawn from the stage of history; for the protection of the ozone layer, the refrigerant has been transformed into hydrofluorocarbons (HFCs) that do not contain chlorine and bromine, and the third-generation refrigerant represented by R134a has begun to be mass-produced and used , but its global warming potential (Global Warming Potential, GWP) is high, which brings the problem of greenhouse effect; considering the destruction of the ozone layer and the greenhouse effect, natural working medium is proposed again as the fourth generation refrigerant, among which It mainly includes CO ₂ , NH ₃ , H ₂ O, hydrocarbons and CH ₄ , N ₂ and He used for low-temperature refrigeration. G. Lorentzen, former president of the International Society of Refrigeration, called natural working fluids the ultimate solution to environmental problems.

The ODP and GWP of refrigerants in traditional vapor compression refrigeration systems are relatively high, and some refrigerants are also toxic and flammable to a certain extent. Leakage of refrigerants can easily cause certain safety hazards and environmental pollution problems, such as the destruction of the ozone layer and the greenhouse effect; In addition, traditional cooling devices in vapor compression refrigeration systems, such as throttle valves, have problems such as low efficiency, large pressure drop, and large throttling loss; It is difficult to process, has the disadvantages of reduced safety and reliability of moving parts, and cannot work with liquid.

Contents of the invention

The embodiment of the present invention provides a natural working medium CO ₂ compression-supersonic two-phase expansion composite refrigeration system and a refrigerator, which are used to solve the technical problems of low refrigeration efficiency and unsafe working medium in the prior art.

An embodiment of the present invention provides a natural working medium _CO2 compression-supersonic two-phase expansion composite refrigeration system, including:

Supersonic two-phase expander, including inlet side, gas outlet side and liquid outlet side;

A circulation circuit, including a first circulation pipeline connected to the gas outlet side, a second circulation pipeline connected to the liquid outlet side, and a confluence of the first circulation pipeline and the second circulation pipeline A third flow line is formed, and the third flow line communicates with the inlet side;

Either one of the second circulation pipeline or the third circulation pipeline is provided with an evaporator, the outlet end of the evaporator communicates with the third circulation pipeline, and the third circulation pipeline is provided with a gas The cooler is used to lower the temperature of the gaseous refrigerant flowing out of the first flow line and the second flow line.

According to an embodiment of the present invention, in the natural working medium _CO2 compression-supersonic two-phase expansion composite refrigeration system, the first flow line is provided with a first compressor, and the inlet end of the first compressor is connected to the outlet gas The side is connected, and the outlet end of the first compressor is connected with the third flow pipeline.

According to an embodiment of the present invention, the natural working medium _CO Compression-supersonic two-phase expansion composite refrigeration system,

A pump and a first evaporator are arranged on the second circulation pipeline;

The inlet end of the pump communicates with the outlet side, the outlet end of the pump communicates with the inlet end of the first evaporator, and the outlet end of the first evaporator communicates with the third flow pipe The roads are connected.

According to an embodiment of the present invention, in the natural working medium CO ₂ compression-supersonic two-phase expansion compound refrigeration system, the pressure value at the outlet end of the first compressor is the same as the pressure value at the inlet side.

According to an embodiment of the present invention, in the natural working medium _CO2 compression-supersonic two-phase expansion compound refrigeration system, a throttling valve is arranged on the first circulation pipeline, and the inlet end of the throttling valve is connected to the gas outlet side The outlet end of the throttle valve communicates with the third flow pipeline.

According to an embodiment of the present invention, the natural working medium _CO Compression-supersonic two-phase expansion composite refrigeration system,

A second evaporator and a second compressor are arranged on the third circulation pipeline;

The inlet end of the second evaporator communicates with the outlet end of the first circulation pipeline and the second circulation pipeline respectively, and the outlet end of the second evaporator communicates with the inlet of the second compressor The ports are connected, and the outlet port of the second compressor is connected with the inlet port of the gas cooler.

According to an embodiment of the present invention, in the natural working fluid CO ₂ compression-supersonic two-phase expansion compound refrigeration system, the pressure value at the outlet end of the second compressor is the same as the pressure value at the inlet side.

According to an embodiment of the present invention, the natural working medium _CO Compression-supersonic two-phase expansion composite refrigeration system,

The supersonic two-phase expander includes a swirl mechanism, a nozzle, a swirl separation pipe, a liquid discharge mechanism and a diffuser connected in sequence;

The inlet side communicates with the swirl mechanism, and the swirl mechanism generates centrifugal force to form a low-temperature effect in the nozzle tube for the working fluid entering through the inlet side, and passes through the swirl separation tube through the The liquid discharge mechanism flows the generated liquid refrigerant to the second flow line and flows the gaseous refrigerant to the first flow through the diffuser.

According to an embodiment of the natural working medium CO ₂ compression-supersonic two-phase expansion composite refrigeration system, the refrigerant in the supersonic two-phase expander is carbon dioxide.

An embodiment of the present invention also provides a refrigerator, including the above-mentioned natural working fluid CO ₂ compression-supersonic two-phase expansion composite refrigeration system.

The natural working medium CO ₂ compression-supersonic two-phase expansion composite refrigeration system and refrigerator provided in the embodiments of the present invention, the natural working medium CO ₂ compression-supersonic two-phase expansion composite refrigeration system includes a supersonic two-phase expander and a supersonic two-phase expansion composite refrigeration system Circulation circuit, and any one of the second flow line or the third flow line is equipped with an evaporator, through which the evaporator can make the refrigerant flowing to the gas cooler be a gaseous refrigerant, and refrigerate through supersonic expansion, and the refrigeration efficiency is high , small pressure drop, low energy consumption, simple and compact structure, low processing difficulty, no moving parts, safe and reliable, and the system can be a liquid refrigerant in the second circulation pipeline or part of the third circulation pipeline, that is, at supersonic speed The two-phase expander can expand to the two-phase region.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the structural representation of an embodiment of the natural working fluid CO2compression-supersonic _two -phase expansion compound refrigeration system of the present invention;

Fig. 2 is the structural representation of another embodiment of the natural working medium CO2compression-supersonic _two -phase expansion compound refrigeration system of the present invention;

Fig. 3 is a schematic structural view of the supersonic two-phase expander in Fig. 1;

Reference signs:

10. Supersonic two-phase expander; 110. Inlet side; 120. Gas outlet side; 130. Liquid outlet side; 140. Swirl flow mechanism; 150. Nozzle; 160. Swirl flow separation pipe; 170. Liquid discharge mechanism; , diffuser;

20. Circulation loop; 210. First circulation pipeline; 2110. First compressor; 2120. Throttle valve; 220. Second circulation pipeline; 2210. Pump; 2220. First evaporator; 230. Third circulation pipeline; 2310, gas cooler; 2320, second evaporator; 2330, second compressor.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments.

Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right" , "vertical", "horizontal", "top", "bottom", "inner", "outer" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing this The embodiments and simplified descriptions of the invention do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

Referring to Fig. 1 to Fig. 3 below, the present invention provides a refrigerator, which can be used as an industrial refrigerator or a domestic refrigeration device, such as a refrigeration system of a supermarket or a cold store, and is not limited here. The refrigerator includes a natural working medium CO ₂ compression-supersonic two-phase expansion composite refrigeration system, which can extract cold energy to cool and cool the external environment.

Please continue to refer to Fig. 1 and Fig. 2, the natural working medium CO ₂ compression-supersonic two-phase expansion composite refrigeration system includes a supersonic two-phase expander 10 and a circulation loop 20, and the supersonic two-phase expander 10 includes an inlet side 110, a gas outlet side 120 and the liquid outlet side 130; the circulation circuit 20 includes a first flow line 210 communicated with the gas outlet side 120, a second flow line 220 communicated with the liquid output side 130, and the first flow line 210 and the second flow line The third circulation pipeline 230 formed by the confluence of the two circulation pipelines 220, the third circulation pipeline 230 communicates with the inlet side 110; any one of the second circulation pipeline 220 or the third circulation pipeline 230 is provided with an evaporator, The outlet end of the evaporator communicates with the third circulation pipeline 230, and the third circulation pipeline 230 is provided with a gas cooler 2310 to cool the gaseous refrigerant flowing out of the first circulation pipeline 210 and the second circulation pipeline 220. Cool down.

That is, both the gas outlet side 120 and the liquid outlet side 130 of the supersonic two-phase expander 10 are provided with communicating pipelines connected thereto, that is, the first circulation pipeline 210 is used to receive the gaseous refrigerant flowing out through the gas outlet side 120 , The second flow line 220 is used to receive the liquid refrigerant flowing out through the liquid outlet side 130, and the gaseous refrigerant can flow through the first flow line 210 to the gas cooler 2310 in the third flow line 230, and the liquid refrigerant The working medium can be converted into a gaseous refrigerant through the evaporator provided in the second flow line 220 or the third flow line 230 and then flow to the gas cooler 2310 in the third flow line 230 . The gas cooler 2310 is used to lower the temperature of the working fluid flowing out of the first flow line 210 and the second flow line 220 , and reduce the temperature to the same temperature as that set at the inlet side 110 of the supersonic two-phase expander 10 . The setting of the evaporator is used for isothermal and isobaric evaporation of the liquid refrigerant into a gaseous refrigerant to produce refrigeration, so as to extract the cooling capacity of the system.

Please continue to refer to FIG. 1 , in one embodiment of the present invention, a first compressor 2110 is provided on the first circulation pipeline 210, the inlet end of the first compressor 2110 communicates with the gas outlet side 120, and the first compressor 2110 The outlet end communicates with the third flow line 230 . The second circulation pipeline 220 is provided with a pump 2210 and a first evaporator 2220, the inlet end of the pump 2210 communicates with the liquid outlet side 130, the outlet end of the pump 2210 communicates with the inlet end of the first evaporator 2220, and the first The outlet end of the evaporator 2220 communicates with the third flow line 230 . The natural refrigerant refrigerant is condensed and separated in the supersonic two-phase expander 10, and a part of the refrigerant refrigerant is condensed into a liquid phase and flows to the second flow line 220 through the liquid outlet side 130, and the pressure is raised by the pump 2210 before flowing to the evaporation The evaporator performs isothermal and isobaric evaporation of the liquid refrigerant to produce refrigeration. The remaining gaseous refrigerant flows through the outlet side 120 to the first circulation pipeline 210 , is compressed and heated by the first compressor 2110 and then mixed with the gaseous refrigerant flowing out of the first evaporator 2220 and enters the third circulation pipeline 230 , and then enter the supersonic two-phase expander 10 again after being cooled by the gas cooler 2310 in the third circulation pipeline 230 to form a closed refrigeration cycle.

Specifically, the function of the first compressor 2110 is to supplement the pressure value lost at the outlet side 120 of the supersonic two-phase expander 10, so that the pressure value of the working medium after passing through the first compressor 2110 is equal to the pressure at the inlet side 110 same value.

Please refer to FIG. 2 , in other embodiments, a throttling valve 2120 is provided on the first flow line 210 , the inlet end of the throttle valve 2120 communicates with the air outlet side 120 , and the outlet end of the throttle valve 2120 communicates with the third flow path. The pipeline 230 is connected. The third circulation pipeline 230 is provided with a second evaporator 2320 and a second compressor 2330; the inlet end of the second evaporator 2320 communicates with the outlet ends of the first circulation pipeline 210 and the second circulation pipeline 220 respectively, The outlet port of the second evaporator 2320 is connected with the inlet port of the second compressor 2330 , and the outlet port of the second compressor 2330 is connected with the inlet port of the gas cooler 2310 . In this embodiment, the natural refrigerant is condensed and separated in the supersonic two-phase expander 10, a part of the refrigerant is condensed into a liquid phase and discharged through the liquid outlet 130, and the other part of the refrigerant is discharged through the gas outlet 120 to The throttling valve 2120 in the first flow line 210 , through the throttle valve 2120 throttling and lowering the temperature, mixed with the liquid refrigerant flowing out of the liquid outlet side 130 and flowing to the second evaporator 2320 in the third flow line 230 The second evaporator 2320 performs isothermal and isobaric evaporation of the refrigerant to produce refrigeration, and the gaseous refrigerant is cooled by the gas cooler 2310 and returned to the supersonic two-phase expander 10 to form a closed refrigeration cycle.

Specifically, the second compressor 2330 is to supplement the pressure values of the gas outlet side 120, the liquid outlet side 130, and the throttling loss of the supersonic two-phase expander 10, so that the pressure value of the working fluid after passing through the second compressor 2330 Same pressure value as the inlet side 110 .

Referring to Fig. 3, in one embodiment of the present invention, the supersonic two-phase expander 10 includes a swirl mechanism 140, a nozzle 150, a swirl separation pipe 160, a liquid discharge mechanism 170 and a diffuser 180 connected in sequence; The side 110 is connected with the swirl mechanism 140, and the swirl mechanism 140 generates a centrifugal force to form a low-temperature effect in the nozzle 150 of the working fluid entering through the inlet side 110, and in the swirl separation pipe 160, the liquid refrigerated by the liquid discharge mechanism 170 The working medium flows to the second flow line 220 and the gaseous refrigerant flows to the first flow line 210 through the diffuser 180 .

Specifically, the refrigerant generates centrifugal force through the swirl mechanism 140, and the isentropic expansion and temperature reduction in the nozzle 150 produces a low-temperature effect. After the temperature drops, a part of the refrigerant will condense and nucleate, generate droplets and further grow, and the liquid phase Due to the tangential velocity and centrifugal action generated by the rotation, it is discharged through the liquid discharge mechanism 170 under the action of the cyclone separation pipe 160 to realize gas-liquid separation, and the remaining gaseous refrigerant is discharged after being decelerated by the diffuser 180 to increase its temperature and pressure. Therefore, most of the pressure can be restored, and the pressure loss at the inlet and outlet of the supersonic two-phase expander 10 is greatly reduced.

In an embodiment of the present invention, the refrigerant used in the supersonic two-phase expander 10 is carbon dioxide. It should be noted that in other embodiments, other environment-friendly, safe and reliable natural working fluids such as nitrogen, argon, neon and helium can be used according to application needs, and different working medium combinations and ratios can also be used as cycle working fluid for efficient cooling.

In summary, the natural working medium _CO2 compression-supersonic two-phase expansion compound refrigeration system provided by the present invention includes a supersonic two-phase expander 10 and a circulation circuit 20, and the second flow line 220 or the third flow line 230 Any of them is equipped with an evaporator, through which the refrigerant flowing to the gas cooler 2310 is a gaseous refrigerant, and through supersonic expansion refrigeration, the refrigeration efficiency is high, the pressure drop is small, the energy consumption is low, the structure is simple and compact, and the processing Low difficulty, no moving parts, safe and reliable, and the system can be a liquid refrigerant in the second flow line 220 or part of the third flow line 230, that is, it can expand to the two-phase region in the supersonic two-phase expander 10 .

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (7)

1. a kind of natural working medium _CO Compression-supersonic two-phase expansion composite refrigeration system, it is characterized in that, comprising: Supersonic two-phase expander, including inlet side, gas outlet side and liquid outlet side; A circulation circuit, including a first circulation pipeline connected to the gas outlet side, a second circulation pipeline connected to the liquid outlet side, and a confluence of the first circulation pipeline and the second circulation pipeline A third flow line is formed, and the third flow line communicates with the inlet side; Either one of the second circulation pipeline or the third circulation pipeline is provided with an evaporator, the outlet end of the evaporator communicates with the third circulation pipeline, and the third circulation pipeline is provided with a gas a cooler, to cool down the gaseous refrigerant flowing out of the first flow line and the second flow line; A first compressor is provided on the first circulation pipeline, the inlet end of the first compressor communicates with the gas outlet side, and the outlet end of the first compressor communicates with the third circulation pipeline ; A pump and a first evaporator are arranged on the second circulation pipeline; The inlet end of the pump communicates with the outlet side, the outlet end of the pump communicates with the inlet end of the first evaporator, and the outlet end of the first evaporator communicates with the third flow pipe The roads are connected. 2. The natural working medium CO ₂ compression-supersonic two-phase expansion compound refrigeration system according to claim 1, characterized in that the pressure value at the outlet end of the first compressor is the same as the pressure value at the inlet side. 3. natural working medium CO according to claim ₁ Compression-supersonic two-phase expansion compound refrigeration system, it is characterized in that, described supersonic two-phase expander comprises the swirl flow mechanism, spray pipe, swirl flow mechanism that are connected successively separation pipe, liquid discharge mechanism and diffuser; The inlet side communicates with the swirl mechanism, and the swirl mechanism generates centrifugal force to form a low-temperature effect in the nozzle tube for the working fluid entering through the inlet side, and passes through the swirl separation tube through the The liquid discharge mechanism flows the generated liquid refrigerant to the second flow line and flows the gaseous refrigerant to the first flow through the diffuser. 4. The natural working medium CO ₂ compression-supersonic two-phase expansion composite refrigeration system according to claim 1, characterized in that the refrigerant in the supersonic two-phase expander is carbon dioxide. 5. A natural working medium _CO Compression-supersonic two-phase expansion composite refrigeration system, characterized in that, comprising: Supersonic two-phase expander, including inlet side, gas outlet side and liquid outlet side; A circulation circuit, including a first circulation pipeline connected to the gas outlet side, a second circulation pipeline connected to the liquid outlet side, and a confluence of the first circulation pipeline and the second circulation pipeline A third flow line is formed, and the third flow line communicates with the inlet side; Either one of the second circulation pipeline or the third circulation pipeline is provided with an evaporator, the outlet end of the evaporator communicates with the third circulation pipeline, and the third circulation pipeline is provided with a gas a cooler, to cool down the gaseous refrigerant flowing out of the first flow line and the second flow line; A throttling valve is provided on the first circulation pipeline, the inlet end of the throttle valve communicates with the gas outlet side, and the outlet end of the throttle valve communicates with the third circulation pipeline; A second evaporator and a second compressor are arranged on the third circulation pipeline; The inlet end of the second evaporator communicates with the outlet end of the first circulation pipeline and the second circulation pipeline respectively, and the outlet end of the second evaporator communicates with the inlet of the second compressor The ports are connected, and the outlet port of the second compressor is connected with the inlet port of the gas cooler. 6. The natural working medium CO ₂ compression-supersonic two-phase expansion compound refrigeration system according to claim 5, characterized in that the pressure value at the outlet end of the second compressor is the same as the pressure value at the inlet side. 7. A refrigerator, characterized in that it comprises the natural working medium CO2compression-supersonic _two -phase expansion composite refrigeration system according to any one of claims 1 to 4; or, any one of claims 5-6 The natural working medium CO ₂ compression-supersonic two-phase expansion composite refrigeration system.

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