An absorption-compression high-temperature heat pump system with liquid injection enthalpy increase

Abstract

This invention discloses an absorption-compression high-temperature heat pump system with liquid injection enthalpy enhancement, relating to the field of high-temperature heat pump technology. It includes a heating subsystem and a liquid injection enthalpy enhancement refrigerant pressurization subsystem connected by pipelines. The liquid injection enthalpy enhancement refrigerant pressurization subsystem includes a condenser, evaporator, compressor, refrigerant flow control valve, second liquid pump, and third liquid pump connected together. The heating subsystem includes a generator, absorber, solution throttling valve, first liquid pump, first heat exchanger, and third heat exchanger connected together. The third heat exchanger is connected to the second heat exchanger, and the second heat exchanger is connected to the fourth liquid pump. This invention, employing the above-described absorption-compression high-temperature heat pump system with liquid injection enthalpy enhancement, combines a second-type absorption heat pump with a liquid injection enthalpy enhancement refrigerant pressurization subsystem to increase absorber pressure, achieving a large temperature rise comparable to two-stage or multi-stage second-type absorption heat pumps under low-temperature heat source conditions.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature heat pumps, and in particular to an absorption-compression high-temperature heat pump system with liquid injection enthalpy increase. Background Art

[0002] Energy conservation and emission reduction are important challenges for human society today. A large amount of low-temperature heat below 100°C is generated in the process of conversion and utilization of various traditional energy sources and renewable energy sources. The sources of these low-temperature heat include various industrial waste heat such as wastewater, waste gas, product heat, and renewable energy such as solar energy and geothermal energy. At present, it is difficult to directly utilize these low-temperature heat, so most of the waste heat is discharged into the environment, resulting in a large amount of energy waste. In order to better recycle and utilize various low-temperature heat, heat pump technology can be used to upgrade the quality of these low-temperature heat for reuse. After the quality of low-temperature heat is improved, it can be reused in industrial production processes, regional heating and other fields. On the one hand, this recycles waste heat, reduces a lot of energy waste and carbon dioxide emissions, and on the other hand, it can bring considerable economic benefits.

[0003] Heat pumps with a quality improvement function can use medium and low temperature heat input to achieve high temperature heat output. Currently, this type of heat pump mainly includes compression heat pumps and second-type absorption heat pumps. Both have practical application cases and can achieve different degrees of temperature increase of heat sources below 100°C. However, there are still problems with high temperature output.

[0004] When compression heat pumps achieve an output temperature above 150°C, most refrigerants require a large pressure ratio, which leads to a rapid decrease in the system performance coefficient. The performance coefficient of compression heat pumps is higher when water is used as the refrigerant, but the refrigerant vapor superheat is higher during the high-pressure ratio compression process, which has an adverse effect on the sealing and long-term stable operation of the compressor. Therefore, compression heat pumps are currently limited in high-temperature output. On the other hand, in the case of a large amount of high-temperature heat demand, compression heat pumps require a large amount of high-grade electricity in addition to medium and low-temperature heat.

[0005] Although the second-type absorption heat pump does not require a large amount of electricity, the current single-stage second-type absorption heat pump can only achieve a temperature increase of less than 40°C when using 80-100°C. The output temperature is limited and it is impossible to achieve an output temperature above 150°C. In order to achieve a temperature increase of 50-70°C, it is usually necessary to build a two-stage or three-stage cycle to continuously increase the absorption pressure and temperature of the high-pressure absorber. These more complex cycle structures directly lead to a very low coefficient of performance of the heat pump system, difficulty in regulation, and high system investment.

[0006] The high-temperature output of compression heat pumps is limited but they have better refrigerant boosting capabilities, while the second type of absorption heat pumps have better high-temperature output capabilities but are complex in structure and have low coefficient of performance. Combining the output characteristics of the two can complement each other and eliminate their shortcomings. However, the existing absorption-compression coupled high-temperature heat pumps still have the problem of complex thermal coupling relationships, which limits their high-temperature output applications. Summary of the invention

[0007] The purpose of the present invention is to provide an absorption-compression high-temperature heat pump system with liquid injection enthalpy increase, which utilizes low-temperature heat below 100°C to achieve high-temperature output above 150°C, and solves the problems of excessive superheat under high pressure ratio of the compressor, complex structure of multi-stage second-class absorption heat pump system, low performance coefficient, high investment, and complex thermal coupling relationship of existing absorption-compression high-temperature heat pumps.

[0008] To achieve the above-mentioned objectives, the present invention provides an absorption-compression high-temperature heat pump system with liquid injection enthalpy increase, comprising a heating subsystem and a liquid injection enthalpy increase refrigerant pressurization subsystem connected by pipelines, the liquid injection enthalpy increase refrigerant pressurization subsystem comprising a connected condenser, an evaporator, a compressor, a refrigerant flow control valve, a second liquid pump and a third liquid pump, the heating subsystem comprising a connected generator, an absorber, a solution throttle valve, a first liquid pump, a first heat exchanger and a third heat exchanger, the third heat exchanger is connected to the second heat exchanger, and the second heat exchanger is connected to the fourth liquid pump.

[0009] Preferably, the generator is provided with a first heat source inlet and a first heat source outlet, which are used for introducing the first heat source and discharging the first heat source respectively.

[0010] Preferably, the condenser is provided with a cooling water inlet and a cooling water outlet, which are used for introducing cooling water and discharging the heated cooling water respectively.

[0011] Preferably, the evaporator is provided with a second heat source inlet for introducing the second heat source; the second heat exchanger is provided with a second heat source outlet for discharging the second heat source after being cooled.

[0012] Preferably, an absorbent dilute solution circulation pipeline is provided between the absorber, the first heat exchanger, the third heat exchanger and the generator, the absorber discharges the first absorbent dilute solution through the absorbent dilute solution outlet, the first absorbent dilute solution enters the first heat exchanger and is converted into the second absorbent dilute solution to flow out, the second absorbent dilute solution enters the third heat exchanger and is converted into the third absorbent dilute solution to flow out, the third absorbent dilute solution is throttled and depressurized by the solution throttle valve and is converted into the fourth absorbent dilute solution and enters the generator through the absorbent dilute solution inlet of the generator;

[0013] The generator utilizes the heat of the first heat source to generate the first refrigerant vapor and simultaneously generate the first absorbent concentrated solution, and continues to pressurize and absorb the refrigerant.

[0014] Preferably, an absorbent concentrated solution circulation pipeline is arranged between the generator, the first heat exchanger and the absorber, the generator discharges the first absorbent concentrated solution through the absorbent concentrated solution outlet, the first absorbent concentrated solution enters the first liquid pump and is converted into the second absorbent concentrated solution flowing out, the second absorbent concentrated solution enters the second heat exchanger and is converted into the third absorbent concentrated solution flowing out, and the third absorbent concentrated solution flows into the absorber through the absorbent concentrated solution inlet of the absorber.

[0015] Preferably, a refrigerant circulation pipeline is arranged between the generator, the condenser, the refrigerant flow control valve, the evaporator, the third liquid pump, the compressor and the absorber. The first refrigerant vapor generated by the generator enters the condenser, and the condenser uses cooling water to condense the first refrigerant vapor into a first refrigerant liquid. The first refrigerant liquid is pressurized by the second liquid pump to generate a second refrigerant liquid, which flows to the refrigerant flow control valve. The refrigerant flow control valve diverts the second refrigerant liquid into a third refrigerant liquid and a fourth refrigerant liquid. The third refrigerant liquid enters the evaporator, and the evaporator absorbs heat from the second heat source to evaporate the third refrigerant liquid into a second refrigerant vapor. The second refrigerant vapor enters the compressor for pressure and temperature increase. The fourth refrigerant liquid is pressurized by the third liquid pump to form a fifth refrigerant liquid, which is sprayed into the compression chamber of the compressor. The fifth refrigerant liquid absorbs the heat of the superheated second refrigerant vapor in the compressor and evaporates. The compressor outputs the third refrigerant vapor to participate in the absorption process.

[0016] Preferably, a normal temperature water circulation pipeline is arranged between the fourth liquid pump, the second heat exchanger, the third heat exchanger and the absorber. The input normal temperature water is pressurized into high-pressure normal temperature water by the fourth liquid pump. The high-pressure normal temperature water absorbs heat through the second heat exchanger and is converted into high-pressure medium-temperature water. The high-pressure medium-temperature water absorbs heat through the third heat exchanger and is converted into high-pressure high-temperature water. The high-pressure high-temperature water enters the absorber through the high-temperature water inlet, absorbs heat in the absorber and evaporates into output high-temperature steam.

[0017] Preferably, the refrigerant circulating in the refrigerant circulation pipeline is water; and the absorbent circulating in the absorbent dilute solution circulation pipeline and the absorbent concentrated solution circulation pipeline is lithium bromide.

[0018] Preferably, the first heat source and the second heat source use various waste heat from industry and production processes, solar energy or geothermal energy.

[0019] Therefore, the present invention adopts the above-mentioned structure of an absorption-compression high-temperature heat pump system with liquid injection enthalpy increase, which has the following beneficial effects:

[0020] (1) The present invention combines the second type absorption heat pump with a liquid injection enthalpy increase refrigerant pressurization subsystem to increase the absorber pressure and achieve a large temperature rise compared to a two-stage or multi-stage second type absorption heat pump under low temperature heat source conditions.

[0021] (2) The system structure of the present invention is simple and the cost is low. Compared with the existing single-stage second-type absorption heat pump, only one compressor and necessary liquid pump and valve are added.

[0022] (3) The present invention can effectively reduce the high superheat of the compressor under high pressure ratio by injecting part of the refrigerant liquid from the condenser into the compressor chamber to absorb the compressor overheat, so that the system can further increase the compression ratio, expand the compression ratio range of water vapor compressibility, and further increase the output temperature of the absorption-compression high-temperature heat pump.

[0023] (4) In the present invention, part of the refrigerant liquid from the condenser is injected into the compressor chamber and evaporated, which reduces the power consumption of the compressor and the heat consumption of the evaporator, and improves the overall performance coefficient of the system when the same high-temperature steam is generated.

[0024] (5) The heat source of the present invention can be a heat source with a relatively low temperature below 100°C, and can be various industrial and production waste heat that is difficult to recycle, low-grade solar energy and geothermal energy, thereby reducing the consumption of fossil energy and achieving the purpose of energy conservation and emission reduction.

[0025] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of an embodiment of an absorption-compression high-temperature heat pump system with liquid injection enthalpy increase according to the present invention;

[0027] Reference numerals: 1, generator; 2, condenser; 3, evaporator; 4, compressor; 5, absorber; 6, first heat exchanger; 7, second heat exchanger; 8, third heat exchanger; V1, solution throttle valve; V2, refrigerant flow control valve; P1, first liquid pump; P2, second liquid pump; P3, third liquid pump; P4, fourth liquid pump; H1, first heat source; H2, second heat source; H3, second heat source after cooling; H4, cooling water; H5, cooling water after heating; W1, input normal temperature water; W2, high pressure normal temperature water; W3, high pressure medium temperature water; W4, high-pressure and high-temperature water; W5, output high-temperature steam; S1, first absorbent dilute solution; S2, second absorbent dilute solution; S3, third absorbent dilute solution; S4, fourth absorbent dilute solution; S5, first absorbent concentrated solution; S6, second absorbent concentrated solution; S7, third absorbent concentrated solution; R1, first refrigerant vapor; R5, second refrigerant vapor; R8, third refrigerant vapor; R2, first refrigerant liquid; R3, second refrigerant liquid; R4, third refrigerant liquid; R6, fourth refrigerant liquid; R7, fifth refrigerant liquid. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0029] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words 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. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0030] Example

[0031] See also Figure 1The present invention provides an absorption-compression high-temperature heat pump system with liquid injection enthalpy increase, comprising a temperature increase subsystem and a liquid injection enthalpy increase refrigerant pressure increase subsystem connected by pipelines, and the liquid injection enthalpy increase refrigerant pressure increase subsystem comprises a connected condenser 2, an evaporator 3, a compressor 4, a refrigerant flow control valve V2, a second liquid pump P2 and a third liquid pump P3. The evaporator 3 is provided with a second heat source H2 inlet for introducing the second heat source H2; the second heat source H2 forms a second heat source H3 after cooling after passing through the evaporator 3. The second heat exchanger 7 is provided with a second heat source outlet for discharging the second heat source H3 after cooling.

[0032] The condenser 2 is provided with a cooling water inlet and a heated cooling water outlet, which are used to introduce cooling water H4 and discharge heated cooling water H5 respectively. The refrigerant vapor inlet of the condenser 2 is connected to the refrigerant vapor outlet of the generator 1; the refrigerant liquid outlet of the condenser 2 is connected to the second liquid pump P2; the second liquid pump P2 is connected to the refrigerant flow control valve V2; the refrigerant flow control valve V2 has a refrigerant liquid inlet and two refrigerant liquid outlets, and the two refrigerant liquid outlets are connected to the evaporator 3 and the third liquid pump P3; the evaporator 3 has a refrigerant liquid inlet and a refrigerant vapor outlet, and the refrigerant vapor outlet of the evaporator 3 is connected to the refrigerant vapor inlet of the compressor 4; the refrigerant liquid outlet of the third liquid pump P3 is connected to the compression chamber of the compressor 4; the refrigerant vapor outlet of the compressor 4 is connected to the refrigerant vapor inlet of the absorber 5.

[0033] Condenser 2 is a condensing device that uses external cooling water to condense refrigerant vapor into refrigerant liquid. The second liquid pump P2 is a liquid pressurizing device used to increase the liquid pressure of the refrigerant liquid R2. The refrigerant flow control valve V2 is a refrigerant liquid flow control device used to control the refrigerant liquid flow to the evaporator 3 and the third liquid pump P3. The evaporator 3 is an evaporating device used to absorb heat from a medium-temperature heat source and evaporate the third refrigerant liquid R4 into the second refrigerant vapor R5. The third liquid pump P3 is a liquid pressurizing device used to increase the liquid pressure of the fourth refrigerant liquid R6. The compressor 4 is a refrigerant vapor pressurizing device used to pressurize the refrigerant vapor to produce a high-pressure third refrigerant vapor R8.

[0034] The temperature raising subsystem includes a connected generator 1, an absorber 5, a solution throttle valve V1, a first liquid pump P1, a first heat exchanger 6 and a third heat exchanger 8. The third heat exchanger 8 is connected to the second heat exchanger 7, and the second heat exchanger 7 is connected to the fourth liquid pump P4. The generator 1 is provided with a first heat source inlet and a first heat source outlet, which are used to introduce the first heat source H1 and discharge the first heat source H1 respectively.

[0035] The absorber 5 has an absorbent concentrated solution inlet and an absorbent dilute solution outlet, which are connected to the first heat exchanger 6; the absorber 5 has a high-temperature water inlet, which is connected to the third heat exchanger 8; the first heat exchanger 6 is connected to the third heat exchanger 8; the third heat exchanger 8 is connected to the generator 1 via the solution throttle valve V1; the generator 1 is connected to the first heat exchanger 6 via the first liquid pump P1.

[0036] The absorber 5 is a gas-liquid mixed absorption device, in which the absorbent concentrated solution absorbs the third refrigerant vapor R8, and uses the heat released during the absorption process to heat the high-pressure high-temperature water W4 to produce output high-temperature steam W5. The first heat exchanger 6 and the third heat exchanger 8 are fluid heat exchange devices, which are used to achieve heat exchange between cold and hot fluids. The solution throttle valve V1 is a fluid throttling and pressure reduction device, which is used to achieve the pressure reduction of the third absorbent dilute solution S3. The generator 1 is a refrigerant vapor generating device, which absorbs the heat of the medium-temperature heat source during the generation process to generate a low-pressure first refrigerant vapor R1 and a first absorbent concentrated solution S5. The first liquid pump P1 is a liquid pressurizing device, which is used to increase the liquid pressure of the first absorbent concentrated solution S5.

[0037] The heating subsystem is connected to the liquid spray enthalpy increase refrigerant pressurization subsystem, and the two form a working fluid circulation loop; the heating subsystem absorbs the refrigerant vapor from the liquid spray enthalpy increase refrigerant pressurization subsystem, uses the high-temperature working fluid to increase the temperature of the high-pressure medium-temperature water, outputs high-temperature steam, and uses the medium-temperature heat source to generate low-pressure refrigerant vapor.

[0038] The liquid injection enthalpy-increasing refrigerant pressurizing subsystem condenses the low-pressure refrigerant vapor from the heating subsystem and then diverts it. One part is compressed after evaporating at medium pressure using a medium-temperature heat source, and the other part is pressurized by a liquid pump and then injected into the compressor chamber to evaporate, outputting high-pressure refrigerant vapor.

[0039] An absorbent dilute solution circulation pipeline is arranged between the absorber 5, the first heat exchanger 6, the third heat exchanger 8 and the generator 1. The first absorbent dilute solution S1 flows out of the absorber 5 through the absorbent dilute solution outlet, the first absorbent dilute solution S1 enters the first heat exchanger 6 and is converted into the second absorbent dilute solution S2 and flows out, the second absorbent dilute solution S2 enters the third heat exchanger 8 and is converted into the third absorbent dilute solution S3 and flows out, the third absorbent dilute solution S3 is throttled and reduced in pressure by the solution throttle valve V1 and is converted into the fourth absorbent dilute solution S4 and enters the generator 1 through the absorbent dilute solution inlet of the generator 1; the generator 1 utilizes the heat of the first heat source H1 to generate the first refrigerant vapor R1, and at the same time generates the first absorbent concentrated solution S5, and continues to pressurize and absorb the refrigerant.

[0040] An absorbent concentrated solution circulation pipeline is arranged between the generator 1, the first heat exchanger 6 and the absorber 5. The generator 1 discharges the first absorbent concentrated solution S5 through the absorbent concentrated solution outlet, the first absorbent concentrated solution S5 enters the first liquid pump P1 and is converted into the second absorbent concentrated solution S6 and flows out, the second absorbent concentrated solution S6 enters the second heat exchanger 7 and is converted into the third absorbent concentrated solution S7 and flows out, and the third absorbent concentrated solution S7 flows into the absorber 5 through the absorbent concentrated solution inlet of the absorber 5.

[0041] The absorbent can be salts, alkalis, alcohols, ionic liquids and other absorbents with strong water absorption capacity. In the present invention, the absorbent circulating in the absorbent dilute solution circulation pipeline and the absorbent concentrated solution circulation pipeline is lithium bromide.

[0042] A refrigerant circulation pipeline is provided between the generator 1, the condenser 2, the refrigerant flow control valve V2, the evaporator 3, the third liquid pump P3, the compressor 4 and the absorber 5, and the refrigerant circulating in the refrigerant circulation pipeline is water. The first refrigerant vapor R1 generated by the generator 1 enters the condenser 2, and the condenser 2 uses the cooling water H4 to condense the first refrigerant vapor R1 into the first refrigerant liquid R2. The first refrigerant liquid R2 is pressurized by the second liquid pump P2 to generate the second refrigerant liquid R3, which flows to the refrigerant flow control valve V2. The refrigerant flow control valve V2 divides the second refrigerant liquid R3 into the third refrigerant liquid R4 and the fourth refrigerant liquid R6. The third refrigerant liquid R4 enters the evaporator 3, and the evaporator 3 absorbs the heat of the second heat source H2, and evaporates the third refrigerant liquid R4 into the second refrigerant vapor R5. The second refrigerant vapor R5 enters the compressor 4 for pressure and temperature increase; the fourth refrigerant liquid R6 is pressurized by the third liquid pump P3 to form the fifth refrigerant liquid R7, which is injected into the compression chamber of the compressor 4. The fifth refrigerant liquid R7 absorbs the heat of the superheated second refrigerant vapor R5 inside the compressor 4 and evaporates. The compressor 4 outputs the third refrigerant vapor R8 to participate in the absorption process.

[0043] The third refrigerant vapor R8 is absorbed by the third absorbent concentrated solution S7 in the absorber 5, producing the first absorbent dilute solution S1, releasing heat and being absorbed by the high-pressure high-temperature water W4, producing the output high-temperature steam W5. The first absorbent dilute solution S1 enters the first heat exchanger 6 to exchange heat with the second absorbent concentrated solution S6, and the third absorbent concentrated solution S7 after heating enters the absorber 5 to continue to participate in absorption and heat release, and the second absorbent dilute solution S2 after cooling enters the third heat exchanger 8; the high-pressure medium-temperature water W3 is heated to high-pressure high-temperature water W4 in the third heat exchanger 8, and the third absorbent dilute solution S3 after cooling is produced; the third absorbent dilute solution S3 enters the generator 1 after throttling and reducing the pressure through the solution throttle valve V1, and is heated by the first heat source H1 to produce the low-pressure first refrigerant vapor R1 to participate in the next refrigerant vapor pressurization process.

[0044] A normal temperature water circulation pipeline is arranged between the fourth liquid pump P4, the second heat exchanger 7, the third heat exchanger 8 and the absorber 5. The input normal temperature water W1 is pressurized into high-pressure normal temperature water W2 by the fourth liquid pump P4. The high-pressure normal temperature water W2 absorbs heat through the second heat exchanger 7 and is converted into high-pressure medium-temperature water W3. The high-pressure medium-temperature water W3 absorbs heat through the third heat exchanger 8 and is converted into high-pressure high-temperature water W4. The high-pressure high-temperature water W4 enters the absorber 5 through the high-temperature water inlet, absorbs heat in the absorber 5 and evaporates into output high-temperature steam W5.

[0045] The first heat source H1 and the second heat source H2 of the system of the present invention are derived from medium-temperature heat sources (80-100°C), which can be various industrial and production waste heat that is difficult to recycle, low-grade solar energy and geothermal energy, thereby reducing the consumption of fossil energy and achieving the goal of energy conservation and emission reduction.

[0046] By combining the second-class absorption heat pump with the liquid injection enthalpy increase refrigerant boosting subsystem, the absorber pressure is increased, and a large temperature rise with a two-stage or multi-stage second-class absorption heat pump can be achieved under the condition of low-temperature heat source in use. By injecting part of the refrigerant liquid from the condenser 2 into the chamber of the compressor 4 to absorb the overheating of the compressor 4, the high superheat of the compressor 4 under the high pressure ratio can be effectively reduced, so that the system can further improve the compression ratio, expand the compression ratio range of the water vapor compressible, and further improve the output temperature of the absorption-compression high-temperature heat pump. Part of the refrigerant liquid from the condenser 2 is injected into the chamber of the compressor 4 and evaporated, which reduces the power consumption of the compressor 4 and the heat consumption of the evaporator, and improves the overall performance coefficient of the system when the same high-temperature steam is produced. The system has a simple structure and low cost. Compared with the existing single-stage second-class absorption heat pump, only one compressor 4 and necessary liquid pumps and valves are added.

[0047] In order to better reflect the beneficial effects of the absorption-compression high-temperature heat pump system with liquid injection enthalpy increase provided by the present invention, an embodiment and a reference system (the position of the compressor and the connection structure of the main components of the system are the same as the system of the present invention, and the compressor does not use liquid injection enthalpy increase for cooling, but uses an external cooling medium for cooling) are simulated and calculated under the same output conditions, and the performance differences between the two are compared.

[0048] In this embodiment, the system performance coefficient COP = Q abs / (Q gen +Q eva +W); where Q abs represents the heat load released by the absorber 5; Q gen Indicates the heat load consumed by the generator; Q eva Indicates the heat load consumed by the evaporator; W indicates the power consumption of the compressor. System temperature rise △T=T abs -T eva .

[0049] Table 1

[0050] System of the present invention Reference system Medium temperature heat source input temperature, ℃ 90 90 Output high temperature steam temperature, ℃ 153.5 153.5 Output high temperature steam flow, kg / h 120.8 120.8 Compressor pressure ratio 4 4 Compressor power consumption, kW 15.57 17.12 Compressor outlet temperature, °C 118.4 248.6 Evaporator heat consumption, kW 105.01 115.44 COP 0.395 0.373

[0051] As can be seen from Table 1, the medium heat source temperature of the two systems is 90°C, the output high-temperature steam is 153.5°C, and the output high-temperature steam flow rate is 120.8kg / h. Under the conditions of the same output and compressor pressure ratio, the system compressor power consumption and evaporator heat consumption of the system provided by the present invention are lower than those of the reference system, which leads to a higher COP of the system provided by the present invention than that of the reference system; under the same compression conditions, the compressor outlet temperature of the system provided by the present invention is only 118.4°C, which is much lower than the compressor outlet temperature of the reference system, indicating that the system structure provided by the present invention effectively reduces the superheat of the compressor under high pressure ratio; in addition, the system structure provided by the present invention only adds a compressor and necessary liquid pumps and valves on the basis of a single-stage second-class absorption heat pump, and has a simple structure and low cost; compared with a single-stage second-class absorption heat pump, the system provided by the present invention can achieve a temperature increase of about 70°C under the same heat source conditions as a single-stage second-class absorption heat pump.

[0052] Therefore, the present invention adopts the above-mentioned structure of an absorption-compression high-temperature heat pump system with liquid injection enthalpy increase. By combining the second-type absorption heat pump with the liquid injection enthalpy increase refrigerant boosting subsystem, the absorber pressure is increased, and a large temperature rise is achieved under the conditions of medium and low temperature heat sources compared to a two-stage or multi-stage second-type absorption heat pump.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An absorption-compression high-temperature heat pump system with liquid injection enthalpy increase, characterized in that: It includes a temperature increasing subsystem and a liquid spraying enthalpy increasing refrigerant pressurizing subsystem connected by pipelines, the liquid spraying enthalpy increasing refrigerant pressurizing subsystem includes a connected condenser, an evaporator, a compressor, a refrigerant flow control valve, a second liquid pump and a third liquid pump, the temperature increasing subsystem includes a connected generator, an absorber, a solution throttle valve, a first liquid pump, a first heat exchanger and a third heat exchanger, the third heat exchanger is connected to the second heat exchanger, and the second heat exchanger is connected to the fourth liquid pump; An absorbent dilute solution circulation pipeline is provided between the absorber, the first heat exchanger, the third heat exchanger and the generator. The absorber discharges the first absorbent dilute solution through the absorbent dilute solution outlet, the first absorbent dilute solution enters the first heat exchanger and is converted into the second absorbent dilute solution to flow out, the second absorbent dilute solution enters the third heat exchanger and is converted into the third absorbent dilute solution to flow out, the third absorbent dilute solution is throttled and depressurized by the solution throttle valve and is converted into the fourth absorbent dilute solution and enters the generator through the absorbent dilute solution inlet of the generator; An absorbent concentrated solution circulation pipeline is provided between the generator, the first heat exchanger and the absorber. The generator discharges a first absorbent concentrated solution through the absorbent concentrated solution outlet. The first absorbent concentrated solution enters the first liquid pump and is converted into a second absorbent concentrated solution and flows out. The second absorbent concentrated solution enters the first heat exchanger and is converted into a third absorbent concentrated solution and flows out. The third absorbent concentrated solution flows into the absorber through the absorbent concentrated solution inlet of the absorber. A refrigerant circulation pipeline is arranged between the generator, the condenser, the refrigerant flow control valve, the evaporator, the third liquid pump, the compressor and the absorber. The first refrigerant vapor generated by the generator enters the condenser. The condenser uses cooling water to condense the first refrigerant vapor into a first refrigerant liquid. The first refrigerant liquid is pressurized by the second liquid pump to generate a second refrigerant liquid, which flows to the refrigerant flow control valve. The refrigerant flow control valve divides the second refrigerant liquid into a third refrigerant liquid and a fourth refrigerant liquid. The third refrigerant liquid enters the evaporator. The evaporator absorbs heat from the second heat source and evaporates the third refrigerant liquid into a second refrigerant vapor. The second refrigerant vapor enters the compressor for pressure and temperature increase. The fourth refrigerant liquid is pressurized by the third liquid pump to form a fifth refrigerant liquid, which is sprayed into a compression chamber of the compressor. The fifth refrigerant liquid absorbs the heat of the superheated second refrigerant vapor in the compressor and evaporates. The compressor outputs the third refrigerant vapor to participate in the absorption process. A normal temperature water circulation pipeline is arranged between the fourth liquid pump, the second heat exchanger, the third heat exchanger and the absorber.

2. An absorption-compression high-temperature heat pump system with liquid injection enthalpy increase according to claim 1, characterized in that: The generator is provided with a first heat source inlet and a first heat source outlet, which are respectively used for introducing the first heat source and discharging the first heat source.

3. The absorption-compression high-temperature heat pump system with liquid injection enthalpy increase according to claim 2, characterized in that: The condenser is provided with a cooling water inlet and a cooling water outlet, which are used for introducing cooling water and discharging the heated cooling water respectively.

4. The absorption-compression high-temperature heat pump system with liquid injection enthalpy increase according to claim 3, characterized in that: The evaporator is provided with a second heat source inlet for introducing the second heat source; the second heat exchanger is provided with a second heat source outlet for discharging the second heat source after being cooled.

5. The absorption-compression high-temperature heat pump system with liquid injection enthalpy increase according to claim 4, characterized in that: The generator utilizes the heat of the first heat source to generate the first refrigerant vapor and simultaneously generate the first absorbent concentrated solution, and continues to pressurize and absorb the refrigerant.

6. The absorption-compression high-temperature heat pump system with liquid injection enthalpy increase according to claim 5, characterized in that: The input normal temperature water is pressurized into high-pressure normal temperature water by the fourth liquid pump. The high-pressure normal temperature water absorbs heat through the second heat exchanger and is converted into high-pressure medium-temperature water. The high-pressure medium-temperature water absorbs heat through the third heat exchanger and is converted into high-pressure high-temperature water. The high-pressure high-temperature water enters the absorber through the high-temperature water inlet, absorbs heat in the absorber, and evaporates into output high-temperature steam.

7. The absorption-compression high-temperature heat pump system with liquid injection enthalpy increase according to claim 6, characterized in that: The refrigerant circulating in the refrigerant circulation pipeline is water; the absorbent circulating in the absorbent dilute solution circulation pipeline and the absorbent concentrated solution circulation pipeline is lithium bromide.

8. The absorption-compression high-temperature heat pump system with liquid injection enthalpy increase according to claim 7, characterized in that: The first heat source and the second heat source use various waste heat from industry and production processes, solar energy or geothermal energy.

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