Condensing equipment and carbon dioxide compression refrigeration system

Abstract

The utility model discloses condensing equipment for a carbon dioxide compression refrigeration system and the carbon dioxide compression refrigeration system comprising the condensing equipment. The condensing equipment comprises a generator for receiving gas carbon dioxide at a first temperature and cooling the gas carbon dioxide at the first temperature into gas carbon dioxide at a second temperature; the intermediate heat exchanger is used for receiving the gas carbon dioxide at the second temperature, so that the gas carbon dioxide at the second temperature is converted into the gas carbon dioxide at the critical temperature; the evaporator enables the gas carbon dioxide at the critical temperature to be cooled by the refrigerant liquid to realize condensation phase change, and the gas carbon dioxide is changed into liquid carbon dioxide to be discharged; a condenser; and an absorber.

Description

Technical Field

[0001] The present application relates to a condensing device for a carbon dioxide compression refrigeration system and a carbon dioxide compression refrigeration system comprising the condensing device. Background Art

[0002] The existing zero-carbon refrigeration systems (CO2 systems) on the market generally use transcritical CO2 compression refrigeration systems in areas where the ambient temperature exceeds 31.1°C. Exhaust cooling devices also generally use finned coil air-cooled coolers. When the temperature of such equipment is higher than 25°C, the system operates under supercritical conditions. At this time, the COP value of the refrigeration system is smaller than that of the subcritical state, making it extremely difficult to promote zero-carbon refrigeration systems in subtropical and tropical areas.

[0003] As the "greenhouse effect" problem becomes increasingly serious, the high GWP refrigerants such as CFCs, HCFCS, and HFCS, which are widely used in the refrigeration field, are first listed in the elimination plan, and the excellent properties of CO2 are considered to be the most promising long-term substitute. Utility Model Content

[0004] The utility model aims to realize the subcritical operation of a CO2 compression refrigeration system in a high temperature environment without the aid of other energy sources.

[0005] The present application provides a condensing device for a carbon dioxide compression refrigeration system, comprising:

[0006] a generator containing an absorbent solution, a first heat exchanger disposed in the generator, an inlet fluid of the first heat exchanger being connected to a discharge port of a compressor of a carbon dioxide compression refrigeration system to receive gaseous carbon dioxide at a first temperature, so that the gaseous carbon dioxide at the first temperature heats the absorbent solution to increase its concentration, and simultaneously the gaseous carbon dioxide at the first temperature is converted into gaseous carbon dioxide at a second temperature, the second temperature being lower than the first temperature;

[0007] an intermediate heat exchanger fluidly connected to an outlet of the first heat exchanger, receiving the gaseous carbon dioxide at the second temperature from the first heat exchanger so that the gaseous carbon dioxide at the second temperature is converted into gaseous carbon dioxide at the critical temperature;

[0008] The evaporator contains the refrigerant liquid. The second heat exchanger is disposed in the evaporator. The inlet of the second heat exchanger can receive the gaseous carbon dioxide at the critical temperature from the intermediate heat exchanger, so that the gaseous carbon dioxide at the critical temperature is cooled by the refrigerant liquid to realize condensation phase change and become liquid carbon dioxide for discharge, and at the same time, a part of the refrigerant liquid is converted into refrigerant vapor;

[0009] A condenser, a third heat exchanger is disposed in the condenser, the condenser is in fluid communication with the generator, and receives the refrigerant vapor generated by heating the absorbent solution, an inlet of the third heat exchanger receives cooling water from the outside, so as to condense the refrigerant vapor into a refrigerant liquid, and the condenser is also in fluid communication with the evaporator to discharge the refrigerant liquid to the evaporator;

[0010] The absorber, the fourth heat exchanger is arranged in the absorber, the absorber is fluidly connected with the evaporator, and receives the refrigerant vapor from the evaporator. The absorber is also fluidly connected with the generator, and receives the absorbent solution with increased concentration. The inlet of the fourth heat exchanger receives cooling water from the outside to cool the refrigerant vapor and convert it into refrigerant liquid. The refrigerant liquid is mixed with the absorbent solution with increased solution to reduce the concentration of the absorbent solution. The absorbent solution with reduced concentration is transported to the generator.

[0011] Advantageously, the intermediate heat exchanger comprises:

[0012] The fifth heat exchanger is arranged between the first heat exchanger and the second heat exchanger, and is used for receiving the gaseous carbon dioxide at the second temperature from the outlet of the first heat exchanger. When the absorbent solution with reduced concentration is transported from the absorber to the generator, it will pass through the fifth heat exchanger and exchange heat with the gaseous carbon dioxide at the second temperature, so that the gaseous carbon dioxide at the second temperature is converted into gaseous carbon dioxide at a third temperature, and the third temperature is lower than the second temperature. The inlet of the second heat exchanger receives the gaseous carbon dioxide at the third temperature from the outlet of the fifth heat exchanger.

[0013] Advantageously, the intermediate heat exchanger further comprises:

[0014] The sixth heat exchanger is arranged between the fifth heat exchanger and the second heat exchanger. The inlet of the sixth heat exchanger receives cooling water from the outside. The gaseous carbon dioxide at the third temperature passes through the sixth heat exchanger and exchanges heat with the cooling water, so that the gaseous carbon dioxide at the third temperature is converted into gaseous carbon dioxide at a critical temperature. The gaseous carbon dioxide at the critical temperature is transported to the inlet of the second heat exchanger.

[0015] Advantageously, the evaporator further comprises a refrigerant pump configured to pump the remaining portion of the refrigerant liquid from the bottom of the evaporator to the top of the evaporator again.

[0016] Advantageously, the condensing device further comprises:

[0017] a seventh heat exchanger disposed between the generator and the absorber, the inlet of the seventh heat exchanger receiving the absorbent solution with increased concentration from the generator, and the outlet of the seventh heat exchanger being located at the top of the absorber,

[0018] The absorbent solution with reduced concentration passes through the seventh heat exchanger from the bottom of the absorber, and the absorbent solution with reduced concentration exchanges heat with the absorbent solution with increased concentration, so that the absorbent solution with reduced concentration is heated, and further passes through the fifth heat exchanger.

[0019] Advantageously, the condensing device further comprises:

[0020] a first fan, which is disposed between the generator and the condenser and is used to transport the refrigerant vapor generated by heating the absorbent solution to the condenser;

[0021] The second fan is arranged between the evaporator and the absorber, and is used for conveying the refrigerant vapor in the evaporator to the absorber.

[0022] Advantageously, the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, the fifth heat exchanger, and the seventh heat exchanger are any one of plate type, shell and tube type, and double-tube type.

[0023] Advantageously, the sixth heat exchanger is a water-cooled condenser or an air cooler.

[0024] Advantageously, the cryogen is water and the absorbent is lithium bromide.

[0025] The present application also provides a carbon dioxide compression refrigeration system, comprising: a compressor; and a condensing device as described above, the condensing device being used to condense gaseous carbon dioxide discharged from the compressor into liquid carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other features and advantages of the exemplary embodiments of the present invention will become more apparent from the following detailed description in conjunction with the accompanying drawings, and the description and drawings are only for illustrative purposes and are not intended to limit the scope of the present invention in any way, wherein:

[0027] Figure 1 A schematic diagram showing a condensation device according to the present application is shown.

[0028] Figure 2 A schematic diagram showing a carbon dioxide compression refrigeration system according to the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the technical solution of the present disclosure clearer, the technical solution of the embodiment of the present disclosure will be clearly and completely described in conjunction with the drawings of the specific embodiments of the present disclosure. The same figure marks in the drawings represent the same parts. It should be noted that the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0030] Compared to the embodiments shown in the drawings, feasible implementations within the scope of the present disclosure may have fewer components, other components not shown in the drawings, different components, differently arranged components, or differently connected components, etc. In addition, two or more components in the drawings may be implemented in a single component, or a single component shown in the drawings may be implemented as multiple separate components.

[0031] Unless otherwise defined, the technical or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present disclosure belongs. The words "first", "second" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. When the number of components is not specified, the number of components may be one or more; similarly, words such as "one", "the", "said" and the like do not necessarily indicate a quantitative limitation. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Up", "down", "left", "right" and the like are only used to indicate the relative orientation relationship when the device is in use or the orientation relationship shown in the drawings. When the absolute position of the described object changes, the relative position relationship may also change accordingly.

[0032] See also Figure 1 A schematic diagram of a condensing device for a carbon dioxide compression refrigeration system according to the present application is described.

[0033] The condensing device comprises a generator 1, in which an absorbent solution can be contained, and a first heat exchanger is arranged in the generator, for example, in the form of a heating coil of the first heat exchanger. The gaseous carbon dioxide at a first temperature (greater than 100° C.) discharged from the discharge port of the compressor of the carbon dioxide compression refrigeration system enters the first heat exchanger, thereby exchanging heat with the absorbent solution, so that the gaseous carbon dioxide at the first temperature is cooled (first cooling) to a gaseous carbon dioxide at a second temperature, and at the same time, the absorbent solution evaporates to generate refrigerant vapor, and at the same time, the concentration of the absorbent solution increases (i.e., a concentrated solution).

[0034] The gaseous carbon dioxide at the second temperature is converted into gaseous carbon dioxide at the critical temperature through the intermediate heat exchanger, and the gaseous carbon dioxide at the critical temperature is transported to the evaporator 4. The evaporator 4 can accommodate the refrigerant liquid, and the second heat exchanger is arranged in the evaporator 4. The gaseous carbon dioxide at the critical temperature enters the second heat exchanger and undergoes heat exchange with the refrigerant liquid in the evaporator, so that the gaseous carbon dioxide at the critical temperature is converted into liquid carbon dioxide, and at the same time, a part of the refrigerant liquid evaporates and becomes refrigerant vapor. The remaining part of the refrigerant liquid is located at the bottom of the evaporator and can be pumped to the top of the evaporator via the refrigerant pump 4-1 to realize the circulation of the refrigerant liquid.

[0035] The refrigerant vapor can be delivered to the top of the absorber 5 through the second fan 4-2. In addition, the absorbent solution with increased concentration discharged from the generator 1 enters the absorber 5. The fourth heat exchanger is arranged in the absorber 5, receives cooling water from the outside, and thus converts the refrigerant vapor into a refrigerant liquid, which is mixed with the absorbent solution with increased concentration, so that the concentration of the absorbent solution is reduced (i.e., a dilute solution). The absorbent solution with reduced concentration can be delivered back to the generator again, as described below.

[0036] The intermediate heat exchanger includes a fifth heat exchanger 2 and a sixth heat exchanger 3. The fifth heat exchanger 2 can receive the gaseous carbon dioxide at the second temperature from the first heat exchanger, and the absorbent solution with reduced concentration passes through the fifth heat exchanger and exchanges heat with the gaseous carbon dioxide at the second temperature, so that the gaseous carbon dioxide at the second temperature is cooled (second cooling) to the gaseous carbon dioxide at the third temperature, and the temperature of the absorbent solution with reduced concentration is increased.

[0037] The sixth heat exchanger 3 is arranged downstream of the fifth heat exchanger 2. The inlet of the sixth heat exchanger 3 receives cooling water from the outside. The gaseous carbon dioxide at the third temperature passes through the sixth heat exchanger, so that the cooling water and the gaseous carbon dioxide at the third temperature undergo heat exchange. The gaseous carbon dioxide at the third temperature is converted (cooled for the third time) into gaseous carbon dioxide at the critical temperature and transported to the inlet of the second heat exchanger.

[0038] The seventh heat exchanger 6 is also provided between the generator 1 and the absorber 5, the absorbent solution with increased concentration from the generator 1 enters the inlet of the seventh heat exchanger 6, and the absorbent solution with reduced concentration from the absorber 5 is pumped through the seventh heat exchanger 6 via the solution pump 5-1, and heat exchange occurs between the two, so that the temperature of the absorbent solution with reduced concentration increases, and the temperature of the absorbent solution with increased concentration decreases, and is optionally delivered to the top of the absorber via the shut-off valve 7. The absorbent solution with reduced concentration then passes through the fifth heat exchanger, as described above.

[0039] The refrigerant vapor from the generator 1 can be transported to the condenser 9 through the first fan 9-1. The third heat exchanger is arranged in the condenser 9, receiving cooling water from the outside to condense the refrigerant vapor into refrigerant liquid, and optionally transporting the refrigerant liquid to the evaporator 4 via the shut-off valve 8.

[0040] The cooling water of the third heat exchanger and the sixth heat exchanger 3 can be returned to the cooling tower after heat exchange.

[0041] The first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, the fifth heat exchanger, and the seventh heat exchanger are any of plate type, shell and tube type, and double-tube type. The sixth heat exchanger is a water-cooled condenser or an air cooler.

[0042] Advantageously, the coolant is water and the absorbent is lithium bromide.

[0043] Figure 1 The eighth heat exchanger 3-1 is also shown, for example, in the form of an air-cooled air cooler. When the temperature is low (below 0°C) for a long time in winter, the gaseous carbon dioxide discharged by the compressor can be directly transported to the eighth heat exchanger 3-1 and then condensed into liquid carbon dioxide. In other words, the eighth heat exchanger can replace the above-mentioned condensing equipment, thereby realizing winter and summer switching.

[0044] Figure 2 Schematic diagram of a carbon dioxide compression refrigeration system according to the present application is shown. The carbon dioxide compression refrigeration system comprises a low temperature compressor 10, a medium temperature compressor 20, and a condensing device 30 as described above. Figure 2 The carbon dioxide compression refrigeration system also includes a regenerator 40, a medium-temperature expansion valve 70, a medium-temperature evaporator 50, a low-temperature expansion valve 80, a low-temperature evaporator 60, a liquid storage tank 90, an ejector 100, a bypass valve 110, and a medium-pressure valve 120.

[0045] The working process of the carbon dioxide compression refrigeration system is described below. The medium temperature compressor 20 pressurizes the high temperature and low pressure gaseous carbon dioxide into high temperature and high pressure gaseous carbon dioxide, and then delivers it to the condensing device 30 as described above. After the condensing device 30 as described above, the high temperature and high pressure gaseous carbon dioxide is converted into liquid carbon dioxide.

[0046] If the temperature of the liquid carbon dioxide is lower than the predetermined threshold, the bypass valve 110 is opened, so that the liquid carbon dioxide passes through the bypass valve 110 to reach the ejector 100. If the temperature of the liquid carbon dioxide is not lower than the predetermined threshold, the bypass valve 110 is closed, so that the liquid carbon dioxide passes through the bypass valve 110 to the regenerator 40, and then reaches the ejector 100.

[0047] After passing through the ejector 100, the temperature and pressure of the liquid carbon dioxide are reduced, and it enters the liquid storage tank 90, and then is respectively transported to the medium temperature expansion valve 70 and the low temperature expansion valve 80. After throttling expansion, the temperature and pressure are reduced again, and heat exchange is performed with the medium temperature evaporator 50 and the low temperature evaporator 60, and the low temperature compressor 10 pressurizes the low pressure carbon dioxide of the low temperature evaporator and transports it to the medium temperature compressor 20.

[0048] Through the condensing equipment of the present application, the carbon dioxide compression refrigeration system utilizes the principle of lithium bromide absorption refrigeration to realize the refrigeration cycle of carbon dioxide in a subcritical state in a high temperature environment (such as in tropical and subtropical regions), thereby achieving energy saving.

[0049] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0050] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A condensing device for a carbon dioxide compression refrigeration system, characterized in that: The condensing equipment includes: a generator containing an absorbent solution, a first heat exchanger disposed in the generator, an inlet fluid of the first heat exchanger being connected to a discharge port of a compressor of a carbon dioxide compression refrigeration system to receive gaseous carbon dioxide at a first temperature, so that the gaseous carbon dioxide at the first temperature heats the absorbent solution to increase its concentration, and simultaneously the gaseous carbon dioxide at the first temperature is converted into gaseous carbon dioxide at a second temperature, the second temperature being lower than the first temperature; an intermediate heat exchanger fluidly connected to an outlet of the first heat exchanger, receiving the gaseous carbon dioxide at the second temperature from the first heat exchanger so that the gaseous carbon dioxide at the second temperature is converted into gaseous carbon dioxide at the critical temperature; The evaporator contains the refrigerant liquid. The second heat exchanger is disposed in the evaporator. The inlet of the second heat exchanger can receive the gaseous carbon dioxide at the critical temperature from the intermediate heat exchanger, so that the gaseous carbon dioxide at the critical temperature is cooled by the refrigerant liquid to realize condensation phase change and become liquid carbon dioxide for discharge, and at the same time, a part of the refrigerant liquid is converted into refrigerant vapor; A condenser, a third heat exchanger is disposed in the condenser, the condenser is in fluid communication with the generator, and receives the refrigerant vapor generated by heating the absorbent solution, an inlet of the third heat exchanger receives cooling water from the outside, so as to condense the refrigerant vapor into a refrigerant liquid, and the condenser is also in fluid communication with the evaporator to discharge the refrigerant liquid to the evaporator; The absorber, the fourth heat exchanger is arranged in the absorber, the absorber is fluidly connected with the evaporator, and receives the refrigerant vapor from the evaporator. The absorber is also fluidly connected with the generator, and receives the absorbent solution with increased concentration. The inlet of the fourth heat exchanger receives cooling water from the outside to cool the refrigerant vapor and convert it into refrigerant liquid. The refrigerant liquid is mixed with the absorbent solution with increased solution to reduce the concentration of the absorbent solution. The absorbent solution with reduced concentration is transported to the generator.

2. The condensing device according to claim 1, characterized in that The intermediate heat exchanger comprises: The fifth heat exchanger is arranged between the first heat exchanger and the second heat exchanger, and is used for receiving the gaseous carbon dioxide at the second temperature from the outlet of the first heat exchanger. When the absorbent solution with reduced concentration is transported from the absorber to the generator, it will pass through the fifth heat exchanger and exchange heat with the gaseous carbon dioxide at the second temperature, so that the gaseous carbon dioxide at the second temperature is converted into gaseous carbon dioxide at a third temperature, and the third temperature is lower than the second temperature. The inlet of the second heat exchanger receives the gaseous carbon dioxide at the third temperature from the outlet of the fifth heat exchanger.

3. The condensing device according to claim 2, characterized in that The intermediate heat exchanger also includes: The sixth heat exchanger is arranged between the fifth heat exchanger and the second heat exchanger. The inlet of the sixth heat exchanger receives cooling water from the outside. The gaseous carbon dioxide at the third temperature passes through the sixth heat exchanger and exchanges heat with the cooling water, so that the gaseous carbon dioxide at the third temperature is converted into gaseous carbon dioxide at a critical temperature. The gaseous carbon dioxide at the critical temperature is transported to the inlet of the second heat exchanger.

4. The condensing device according to any one of claims 1 to 3, characterized in that The evaporator further includes a refrigerant pump configured to pump the remaining portion of the refrigerant liquid from the bottom of the evaporator to the top of the evaporator again.

5. The condensing device according to claim 2, characterized in that: The condensing device also includes: a seventh heat exchanger disposed between the generator and the absorber, the inlet of the seventh heat exchanger receiving the absorbent solution with increased concentration from the generator, and the outlet of the seventh heat exchanger being located at the top of the absorber, The absorbent solution with reduced concentration passes through the seventh heat exchanger from the bottom of the absorber, and the absorbent solution with reduced concentration exchanges heat with the absorbent solution with increased concentration, so that the absorbent solution with reduced concentration is heated, and further passes through the fifth heat exchanger.

6. The condensing device according to any one of claims 1 to 3, characterized in that The condensing device also includes: a first fan, which is disposed between the generator and the condenser and is used to transport the refrigerant vapor generated by heating the absorbent solution to the condenser; The second fan is arranged between the evaporator and the absorber, and is used for conveying the refrigerant vapor in the evaporator to the absorber.

7. The condensing device according to any one of claims 1 to 3, characterized in that The first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, the fifth heat exchanger, and the seventh heat exchanger are any of a plate type, a shell and tube type, and a double-tube type.

8. The condensing device according to claim 3, characterized in that The sixth heat exchanger is a water-cooled condenser or an air cooler.

9. The condensing device according to any one of claims 1 to 3, characterized in that: The refrigerant is water, and the absorbent is lithium bromide.

10. A carbon dioxide compression refrigeration system, characterized in that: The carbon dioxide compression refrigeration system comprises: compressor; The condensing device according to any one of claims 1 to 9, which is used to condense gaseous carbon dioxide discharged from a compressor into liquid carbon dioxide.

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