Large-temperature-difference cascade heat extraction and heating water vapor simultaneous production heat pump system

Abstract

The invention provides a water vapor simultaneous production heat pump system for large-temperature-difference cascade heat extraction and heating, and belongs to the field of compression heat pumps. The problems that industrial-grade steam and high-temperature hot water cannot be synchronously and efficiently produced in a single heat pump system, large-temperature-difference gradient utilization of heat source media is difficult to achieve, and energy consumption and system stability of steam / hot water two-way output are low are solved. A large-temperature-difference geothermal gradient flow is forcibly constructed by adopting double evaporators connected in series, and the refrigerant flow of a high / low-temperature section is regulated and controlled in cooperation with double expansion valves, so that the heat source waste heat extraction rate is remarkably increased; the double condensers are connected in series to integrate the sensible heat supply function and the steam deep heating function, so that the system synchronously outputs high-temperature hot water and saturated steam; or an outlet of the evaporator is directly connected with the pre-compressor, meanwhile, the ejector is additionally arranged at the front end of the main compressor, and medium-pressure gas is automatically sucked by high-pressure airflow to be mixed and pressurized, so that an energy-saving combination is formed; or the bridging form of the second intermediate heat exchanger is optimized into a multi-stage heat recovery framework, and stepped transmission of CO2 waste heat to refrigerant steam energy is achieved.

Description

Technical Field

[0001] This invention relates to the field of compression heat pump technology, and more specifically, to a water vapor heat pump system that combines heat extraction and heating in a large temperature difference stepped manner. Background Technology

[0002] Against the backdrop of energy efficiency bottlenecks and insufficient comprehensive utilization in heat source development, the demand for large temperature difference extraction of heat source media and simultaneous steam / hot water supply is becoming increasingly urgent. In heat pump technology, the synergistic circulation of dual refrigerants (including CO2) can theoretically improve energy quality and simultaneously achieve deep heat source development and simultaneous steam and water production. However, research has found that existing systems face three major technical challenges: first, the utilization rate of waste heat from the heat source is low due to insufficient heat transfer temperature difference, resulting in energy waste; second, the phase change of steam and the sensible heat of hot water require separate independent condensers, making the system complex and subject to cross-temperature losses at the hot and cold ends; and third, the direct entry of low-pressure mixed gas flow into the main compressor causes high entropy increase and surge risks, limiting system stability.

[0003] This study reveals a core contradiction in system coupling: the traditional parallel architecture of dual evaporators struggles to coordinate a continuous temperature drop chain with a large temperature difference, while single-stage compression cannot simultaneously meet the energy efficiency requirements of the low-temperature CO2 range and the high-grade refrigerant vapor generation. Irreversible compression losses caused by evaporator outlet airflow mixing have been identified as a key energy efficiency bottleneck, making the optimization of energy transfer paths between compression stages crucial. Based on these challenges, a systematic solution integrating cascaded heating, cross-cycle decoupling, and entropy-reducing compression is urgently needed. This invention proposes a large temperature difference, wide temperature range collaborative architecture: a geothermal gradient flow is forcibly established through series evaporators, with independent flow control by dual expansion valves adapting to the temperature range; an innovative intermediate heat exchanger bridges the CO2 sensible heat cycle and refrigerant cycle, achieving physically isolated energy transfer; simultaneously, by integrating sensible heat supply and deep steam preheating functions, a series condenser completes phase change evaporation and couples with a steam compressor for enhanced output, simultaneously producing industrial steam and high-temperature hot water within a single system, achieving efficient matching between cascaded energy utilization and diversified industrial energy supply needs. Summary of the Invention

[0004] The technical problem to be solved by this invention is:

[0005] To address the problem that existing heat pump systems cannot simultaneously and efficiently produce industrial-grade steam and high-temperature hot water within a single architecture, and that it is difficult to simultaneously achieve the cascaded utilization of the heat source medium with a large temperature difference, reduce energy consumption and improve system stability through dual output of steam / hot water.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] This invention provides a water-vapor co-generation heat pump system with large temperature difference cascade heat extraction and heating, comprising a first evaporator, a first intermediate heat exchanger, a first compressor, a first condenser, a first expansion valve, a second evaporator, a second compressor, a second expansion valve, a third compressor, a fourth compressor, a second condenser, a third expansion valve, a first flow regulating valve, a second flow regulating valve, and a fifth compressor.

[0008] The first evaporator has a heat source medium inlet, and its heat source medium outlet is connected to the heat source medium inlet of the second evaporator. The second evaporator has a heat source medium outlet for discharging the medium.

[0009] The refrigerant outlet on the low-temperature side of the first intermediate heat exchanger is connected to the inlet of the first compressor. The outlet of the first compressor is connected to the refrigerant inlet of the first condenser. One branch of the refrigerant outlet of the first condenser is connected to the inlet of the first expansion valve. The outlet of the first expansion valve is connected to the refrigerant inlet of the second evaporator. The refrigerant outlet of the second evaporator is connected to the inlet of the second compressor. The outlet of the second compressor merges with another branch of the refrigerant outlet on the low-temperature side of the first intermediate heat exchanger. Another branch of the refrigerant outlet of the first condenser is connected to the inlet of the second expansion valve. The outlet of the second expansion valve is connected to the inlet of the first evaporator. The refrigerant outlet of the first evaporator is connected to the inlet of the third compressor. The outlet of the third compressor is connected to the refrigerant inlet on the low-temperature side of the first intermediate heat exchanger. The refrigerant outlet on the high-temperature side of the first intermediate heat exchanger is connected to the inlet of the fourth compressor. The outlet of the fourth compressor is connected to the refrigerant inlet of the second condenser. The second condenser is connected to the inlet of the third expansion valve. The outlet of the third expansion valve is connected to the refrigerant inlet on the high-temperature side of the first intermediate heat exchanger.

[0010] The first condenser has a heated medium inlet, and a branch of the heated medium outlet of the first condenser is connected to the inlet of the first flow regulating valve. The first flow regulating valve has a heated medium outlet for discharging the medium.

[0011] Another branch of the outlet of the heated medium of the first condenser is connected to the inlet of the second flow regulating valve. The outlet of the second flow regulating valve is connected to the inlet of the heated medium of the second condenser. The outlet of the heated medium of the second condenser is connected to the inlet of the fifth compressor. The fifth compressor has an outlet for outputting the medium.

[0012] This invention provides a water-vapor co-generation heat pump system with large temperature difference cascade heat extraction and heating, comprising a first evaporator, a first intermediate heat exchanger, a first compressor, a first condenser, a first expansion valve, a second evaporator, a second expansion valve, a third compressor, a fourth compressor, a second condenser, a third expansion valve, a first flow regulating valve, a second flow regulating valve, a fifth compressor, and a first ejector.

[0013] The first evaporator has a heat source medium inlet, and its heat source medium outlet is connected to the heat source medium inlet of the second evaporator. The second evaporator has a heat source medium outlet for discharging the medium.

[0014] The refrigerant outlet on the low-temperature side of the first intermediate heat exchanger is connected to the working fluid inlet of the first ejector. The refrigerant outlet of the second evaporator is connected to the ejector fluid inlet of the first ejector. After the two branches mix, the mixed fluid outlet of the first ejector is connected to the inlet of the first compressor. The outlet of the first compressor is connected to the refrigerant inlet of the first condenser. One branch of the refrigerant outlet of the first condenser is connected to the inlet of the first expansion valve. The outlet of the first expansion valve is connected to the refrigerant inlet of the second evaporator. The other branch of the refrigerant outlet of the first condenser is connected to the inlet of the second expansion valve. The outlet of the second expansion valve is connected to the refrigerant inlet of the first evaporator. The refrigerant outlet of the first evaporator is connected to the inlet of the third compressor. The outlet of the third compressor is connected to the low-temperature side refrigerant inlet of the first intermediate heat exchanger. The refrigerant outlet on the high-temperature side of the first intermediate heat exchanger is connected to the inlet of the fourth compressor. The outlet of the fourth compressor is connected to the refrigerant inlet of the second condenser. The second condenser is connected to the inlet of the third expansion valve. The outlet of the third expansion valve is connected to the high-temperature side refrigerant inlet of the first intermediate heat exchanger.

[0015] The first condenser has a heated medium inlet, and a branch of the heated medium outlet of the first condenser is connected to the inlet of the first flow regulating valve. The first flow regulating valve has a heated medium outlet for discharging the medium.

[0016] Another branch of the outlet of the heated medium of the first condenser is connected to the inlet of the second flow regulating valve. The outlet of the second flow regulating valve is connected to the inlet of the heated medium of the second condenser. The outlet of the heated medium of the second condenser is connected to the inlet of the fifth compressor. The fifth compressor has an outlet for outputting the medium.

[0017] This invention provides a water-vapor co-generation heat pump system with large temperature difference cascade heat extraction and heating, comprising a first evaporator, a second evaporator, a third condenser, a fourth expansion valve, a fifth expansion valve, a sixth compressor, a second intermediate heat exchanger, a seventh compressor, an eighth compressor, a fourth condenser, a third flow regulating valve, a fourth flow regulating valve, and a ninth compressor.

[0018] The first evaporator has a heat source medium inlet, and its heat source medium outlet is connected to the heat source medium inlet of the second evaporator. The second evaporator has a heat source medium outlet for discharging the medium.

[0019] One branch of the refrigerant outlet of the third condenser is connected to the fourth expansion valve, the outlet of the fourth expansion valve is connected to the refrigerant inlet of the first evaporator, and the refrigerant outlet of the first evaporator is connected to the inlet of the seventh compressor.

[0020] Another branch of the refrigerant outlet of the third condenser is connected to the inlet of the fifth expansion valve. The outlet of the fifth expansion valve is connected to the refrigerant inlet of the second evaporator. The refrigerant outlet of the second evaporator is connected to the inlet of the sixth compressor. The outlet of the sixth compressor is connected to the refrigerant inlet on the low-temperature side of the second intermediate heat exchanger. The refrigerant outlet on the low-temperature side of the second intermediate heat exchanger merges with the refrigerant outlet of the first evaporator and then connects to the inlet of the seventh compressor. The outlet of the seventh compressor is connected to the refrigerant inlet of the third condenser.

[0021] The refrigerant outlet on the high-temperature side of the second intermediate heat exchanger is connected to the inlet of the eighth compressor. The outlet of the eighth compressor is connected to the refrigerant inlet of the fourth condenser. The refrigerant outlet of the fourth condenser is connected to the refrigerant inlet on the high-temperature side of the second intermediate heat exchanger.

[0022] The third condenser has a heated medium inlet, and a branch of the heated medium outlet of the third condenser is connected to the inlet of the third flow regulating valve. The third flow regulating valve has a heated medium outlet for discharging the medium.

[0023] Another branch of the outlet of the heated medium of the third condenser is connected to the inlet of the fourth flow regulating valve. The outlet of the fourth flow regulating valve is connected to the inlet of the heated medium of the fourth condenser. The outlet of the heated medium of the fourth condenser is connected to the inlet of the ninth compressor. The ninth compressor is provided with an outlet for the heated medium to output the medium.

[0024] Furthermore, it also includes a tenth compressor.

[0025] The refrigerant outlet of the first evaporator is connected to the inlet of the tenth compressor. The outlet of the tenth compressor merges with the refrigerant outlet on the low-temperature side of the second intermediate heat exchanger and then connects to the inlet of the seventh compressor.

[0026] Furthermore, it also includes a second injector.

[0027] The working fluid inlet of the second ejector is connected to the refrigerant outlet on the low-temperature side of the second intermediate heat exchanger, and the ejector fluid inlet of the second ejector is connected to the refrigerant outlet of the first evaporator. After the two pipelines merge, the mixed fluid outlet of the second ejector is connected to the inlet of the seventh compressor.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] (1) This invention constructs a large temperature difference cascade utilization path for the heat source medium by arranging two evaporators in series, realizing continuous extraction of heat energy from high to low; combined with independently controlled dual expansion valves to form a dual-path throttling system, accurately adapting to the flow requirements of heat sources at different temperature levels. This connection form breaks through the temperature range limitation of traditional single evaporator systems and solves the industry pain point of low waste heat utilization rate of heat sources.

[0030] (2) This invention, through a parallel-series composite flow channel design, enables the heating medium to simultaneously and efficiently prepare steam and hot water in a single system. The hot water branch flows directly through the condenser to absorb the sensible heat of CO2 and outputs high-temperature liquid water; the steam branch relies on a relay heating structure of preheating and phase change by a dual condenser, combined with the quality improvement of the steam compressor, to form a continuous steam generation channel. This connection form ensures that the two output streams are independently controllable and have optimal energy sources from a physical structure perspective, effectively solving the redundancy problem of traditional systems requiring separate heat pumps to meet the dual supply of steam and water.

[0031] (3) This invention uses an intermediate heat exchanger to bridge the CO2 and refrigerant cycles, achieving heat transfer through physically isolated parallel flow channels. The CO2 cycle is fully responsible for geothermal extraction, and its outlet gas flow enters the low-temperature side of the intermediate heat exchanger after pre-compression; the refrigerant cycle operates independently on the high-temperature side, obtaining energy only through heat exchange on the metal wall. This connection method completely avoids the risk of mixing of the two refrigerants and ensures the purity of steam generation.

[0032] (4) This invention reconstructs the interstage connection logic of the compressor by embedding a pre-compression unit and an ejector in the airflow path. The pre-compression unit is directly connected to the evaporator outlet and prioritizes the processing of low-temperature and low-pressure airflow. The ejector uses the kinetic energy of medium-pressure fluid to eject low-pressure working fluid to achieve mixing and pressurization. This layout structurally reduces the inlet load of the main compressor and eliminates the entropy increase of airflow mixing, forming an inherently energy-saving architecture. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of a water vapor co-generation heat pump system for large temperature difference cascade heat extraction and heating in this invention. Figure 1 ;

[0034] Figure 2 This is a schematic diagram of the structure of a water vapor co-generation heat pump system for large temperature difference cascade heat extraction and heating in this invention. Figure 2 ;

[0035] Figure 3 This is a schematic diagram of the structure of a water vapor co-generation heat pump system for large temperature difference cascade heat extraction and heating in this invention. Figure 3 ;

[0036] Figure 4 This is a schematic diagram of the structure of a water vapor co-generation heat pump system for large temperature difference cascade heat extraction and heating in this invention. Figure 4 ;

[0037] Figure 5 This is a schematic diagram of the structure of a water vapor co-generation heat pump system for large temperature difference cascade heat extraction and heating in this invention. Figure 5 .

[0038] Explanation of reference numerals in the attached figures:

[0039] 1. First evaporator; 2. First intermediate heat exchanger; 3. First compressor; 4. First condenser; 5. First expansion valve; 6. Second evaporator; 7. Second compressor; 8. Second expansion valve; 9. Third compressor; 10. Fourth compressor; 11. Second condenser; 12. Third expansion valve; 13. First flow regulating valve; 14. Second flow regulating valve; 15. Fifth compressor; 16. Third condenser; 17. Fourth expansion valve; 18. Fifth expansion valve; 19. Sixth compressor; 20. Second intermediate heat exchanger; 21. Seventh compressor; 22. Eighth compressor; 23. Fourth condenser; 24. Third flow regulating valve; 25. Fourth flow regulating valve; 26. Ninth compressor; 27. Tenth compressor; 28. Second ejector; 29. ​​First ejector; 101. Heat source medium input pipeline; 102. Heat source medium transmission pipeline; 103. Heat source medium output pipeline; 104. First pipeline; 105. Second pipeline; 106. Third pipeline; 107. Fourth pipeline; 108. Fifth pipeline; 109. Sixth pipeline; 110. Seventh pipeline; 111. Eighth pipeline; 112. Ninth pipeline; 113. Tenth pipeline; 114. Eleventh pipeline; 115. Twelfth pipeline; 116. Thirteenth pipeline; 117. Fourteenth pipeline; 118. Pipeline 15; 119. Pipeline 16; 120. Pipeline 17; 121. Pipeline 18; 122. Pipeline 19; 123. Pipeline 20; 124. Pipeline 21; 125. Pipeline 22; 126. Pipeline 23; 127. Pipeline 24; 128. Pipeline 25; 129. Pipeline 26; 130. Pipeline 27; 204. Pipeline 28; 205. Pipeline 29; 206. Pipeline 30; 207. Pipeline 31; 208. Pipeline 32; 209. Pipeline 33; 210. Pipeline 34; 21 1. Pipeline 35; 212. Pipeline 36; 213. Pipeline 37; 214. Pipeline 38; 215. Pipeline 39; 216. Pipeline 40; 217. Pipeline 41; 218. Pipeline 42; 219. Pipeline 43; 220. Pipeline 44; 221. Pipeline 45; 222. Pipeline 46; 223. Pipeline 47; 224. Pipeline 48; 225. Pipeline 49; 226. Pipeline 50; 227. Pipeline 51; 228. Pipeline 52; 229. Pipeline 53; 230. Pipeline 54. Detailed Implementation

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] Specific Implementation Plan One: Specific Implementation Plan One: Combining Figure 1 As shown, this invention provides a water-vapor co-generation heat pump system with large temperature difference cascade heat extraction and heating, including a first evaporator 1, a first intermediate heat exchanger 2, a first compressor 3, a first condenser 4, a first expansion valve 5, a second evaporator 6, a second compressor 7, a second expansion valve 8, a third compressor 9, a fourth compressor 10, a second condenser 11, a third expansion valve 12, a first flow regulating valve 13, a second flow regulating valve 14, and a fifth compressor 15.

[0042] The inlet of the first evaporator 1 is connected to the heat source medium input pipeline 101. The outlet of the first evaporator 1 is connected to the inlet of the second evaporator 6 via the heat source medium transmission pipeline 102. The outlet of the second evaporator 6 outputs the medium via the heat source medium output pipeline 103.

[0043] The refrigerant outlet on the low-temperature side of the first intermediate heat exchanger 2 is connected to the inlet of the first compressor 3 via the first pipe 104 and the second pipe 105. The outlet of the first compressor 3 is connected to the refrigerant inlet of the first condenser 4 via the third pipe 106. The refrigerant outlet of the first condenser 4 is connected to the inlet of the first expansion valve 5 via the fourth pipe 107 and the fifth pipe 108. The outlet of the first expansion valve 5 is connected to the refrigerant inlet of the second evaporator 6 via the sixth pipe 109. The refrigerant outlet of the second evaporator 6 is connected to the inlet of the second compressor 7 via the seventh pipe 110. The outlet of the second compressor 7 is connected to the first pipe 104 via the eighth pipe 111 and then converges to the second pipe 105. The refrigerant outlet of the first condenser 4 is connected to the second expansion valve 8 via the fourth pipe 107 and the ninth pipe 112. The refrigerant inlet of the first evaporator 1 is connected via the inlet of the second expansion valve 8 through the tenth pipe 113. The refrigerant outlet of the first evaporator 1 is connected via the eleventh pipe 114 to the inlet of the third compressor 9. The outlet of the third compressor 9 is connected via the twelfth pipe 115 to the low-temperature side refrigerant inlet of the first intermediate heat exchanger 2. The high-temperature side refrigerant outlet of the first intermediate heat exchanger 2 is connected via the thirteenth pipe 116 to the inlet of the fourth compressor 10. The outlet of the fourth compressor 10 is connected via the fourteenth pipe 117 to the refrigerant inlet of the second condenser 11. The second condenser 11 is connected via the fifteenth pipe 118 to the inlet of the third expansion valve 12. The outlet of the third expansion valve 12 is connected via the sixteenth pipe 119 to the high-temperature side refrigerant inlet of the first intermediate heat exchanger 2.

[0044] The heated medium is connected to the inlet of the first condenser 4 via the seventeenth pipe 120. The outlet of the heated medium in the first condenser 4 is connected to the inlet of the first flow regulating valve 13 via the eighteenth pipe 121 and the nineteenth pipe 122. The outlet of the first flow regulating valve 13 outputs the medium via the twentieth pipe 123.

[0045] The heated medium is connected to the inlet of the first condenser 4 via the seventeenth pipe 120. The outlet of the heated medium of the first condenser 4 is connected to the inlet of the second flow regulating valve 14 via the eighteenth pipe 121 and the twenty-first pipe 124. The outlet of the second flow regulating valve 14 is connected to the inlet of the second condenser 11 via the twenty-second pipe 125. The outlet of the heated medium of the second condenser 11 is connected to the inlet of the fifth compressor 15 via the twenty-third pipe 126. The outlet of the fifth compressor 15 outputs the medium via the twenty-fourth pipe 127.

[0046] The operating principle of this implementation plan is as follows:

[0047] The high-temperature heat source medium enters the first evaporator 1 through the heat source medium input pipe 101, releases heat and then cools down. It then flows into the second evaporator 6 through the heat source medium transmission pipe 102 to absorb heat again. Finally, the low-temperature heat source medium is discharged through the heat source medium output pipe 103.

[0048] Low-temperature CO2 is throttled by the second expansion valve 8 and enters the first evaporator 1 for heat absorption and evaporation. Low-temperature CO2 from another branch is throttled by the first expansion valve 5 and enters the second evaporator 6 for heat absorption and evaporation. The CO2 from the outlet of the second evaporator 6 is initially compressed by the second compressor 7, and the CO2 from the outlet of the first evaporator is compressed by the third compressor 9 and enters the low-temperature side of the first intermediate heat exchanger 2. The two CO2 streams are mixed and then deeply compressed by the first compressor 3. The high-temperature CO2 after compression is released as sensible heat in the first condenser 4.

[0049] The liquid refrigerant absorbs the residual heat of CO2 on the high-temperature side of the first intermediate heat exchanger 2 and evaporates. The refrigerant vapor is compressed to high temperature and high pressure by the fourth compressor 10, and releases latent heat in the second condenser 11 to cause water phase change and evaporation. The condensate is depressurized by the third expansion valve 12 and returned to the first intermediate heat exchanger 2.

[0050] After entering through the seventeenth pipe 120, the cold water absorbs the sensible heat of CO2 in the first condenser 4 and is heated up. Then, it is output as high-temperature hot water through the nineteenth pipe 122, the first flow regulating valve 13, and the twentieth pipe 123. The cold water in the other branch is preheated by the first condenser 4 and enters the second condenser 11 through the second flow regulating valve 14 to evaporate into saturated steam. Then, it is pressurized and heated by the fifth compressor 15 and output as superheated steam through the twenty-fourth pipe 127.

[0051] The implementation method of this plan is as follows:

[0052] The medium-deep geothermal water temperature in the inlet heat source medium input pipeline 101 is 50℃. It is cooled to 35℃ by the first evaporator 1, and then cooled to 20℃ by the second evaporator 6 before being output. The 30℃ temperature difference achieves an 85% geothermal extraction rate.

[0053] In the high-temperature section, the refrigerant CO2 evaporates at 35℃ and 4.8 MPa, which is the supercritical state. After compression by the third compressor 9, the outlet refrigerant CO2 pressure is 6.0 MPa and the temperature is 80℃.

[0054] In the low-temperature section, the refrigerant CO2 evaporates at a temperature of 15℃ and a pressure of 4.5 MPa, which is the supercritical state. After compression by the second compressor 7, the outlet refrigerant CO2 pressure is 5.8 MPa and the temperature is 60℃.

[0055] The refrigerant R245fa evaporates at 65°C, driven by the first intermediate heat exchanger 2, at a pressure of 0.58 MPa. After being compressed by the fourth compressor 10, the outlet pressure of the refrigerant R245fa is 1.8 MPa, and the temperature is 100°C.

[0056] The CO2 mixture from the two branches is pressurized to 100℃ and 12.0MPa by the first compressor 3. The first condenser 4 releases sensible heat, producing 90℃ hot water. The second condenser 11 releases latent heat, heating the cold water to 90℃ saturated steam, which is then pressurized and heated to 120℃ superheated steam by the fifth compressor 15.

[0057] The ratio of steam to water is controlled by a flow regulating valve. When the steam to hot water ratio is 1:1.5 (mass ratio), the system's coefficient of performance (COP) is not less than 2.5.

[0058] Overall, four effects were achieved. First, the energy efficiency of utilizing the large temperature difference in the heat source medium was deepened through the synergy of two-stage CO2 compression and intermediate heat exchange. The newly added intermediate heat exchanger allows the heat from the high-temperature CO2 to be recovered to the low-temperature CO2, significantly reducing the power consumption of the main compressor. The working fluid at the outlet of the two-way CO2 evaporator is centrally pressurized by the compressor, breaking through the temperature rise limitation of a single compressor and achieving efficient heating over a wider temperature range. Second, the innovative coupling of the CO2 sensible heat cycle and the refrigerant variable cycle upgrades the integration and heat energy quality of water and steam production. That is, while producing high-temperature hot water with supercritical sensible heat, it also preheats the water in the steam branch. After being preheated by the sensible heat of CO2, the steam branch absorbs the latent heat of the refrigerant for evaporation, reducing energy consumption in the phase change stage and increasing steam production. Third, the newly added internal heat recovery structure of the CO2 cycle allows the low-temperature side of the intermediate heat exchanger to operate entirely in a closed loop with CO2 working fluid. The high-temperature CO2 releases heat to preheat the low-temperature CO2, achieving self-optimization of the CO2 cycle and reducing dependence on external heat sources. Fourth, the refrigerant division of labor and the compression architecture are refined to meet the needs of in-depth heat source development. CO2 focuses on sensible heat transfer and heat upgrade in the medium and low temperature range, and achieves gradient temperature increase through a three-stage compressor, while the other refrigerant focuses on the release of latent heat at high temperatures, with independent circulation to avoid temperature crossover.

[0059] This invention, through multi-stage compression, intermediate heat exchange coupling, and precise matching of refrigerant characteristics, achieves deep utilization of the large temperature difference in the heat source medium while simultaneously producing high-grade heat energy in a single system, significantly improving the overall energy efficiency and economic value of geothermal resources. Compared to traditional heat pump solutions, this system features two major upgrades: intermediate heat exchanger bridging CO2 two-stage compression and steam branch preheating. While maintaining the core advantages of large temperature difference utilization of the heat source medium and simultaneous water and steam production, it adds CO2 circulation self-regeneration and optimized steam generation energy consumption, improving the overall system energy efficiency and further enhancing the stability of steam and hot water output.

[0060] Specific Implementation Plan Two: Combining Figure 2 As shown, unlike Specific Implementation Scheme 1, the second compressor 7 is replaced by the first ejector 29. The working fluid inlet of the first ejector 29 is connected to the refrigerant outlet on the low-temperature side of the first intermediate heat exchanger 2 via the twenty-fifth pipe 128, the ejector fluid inlet is connected to the refrigerant outlet of the second evaporator 6 via the twenty-sixth pipe 129, and the mixed fluid outlet is connected to the inlet of the first compressor via the twenty-seventh pipe 130. The first ejector 29 ejects the low-pressure CO2 from the outlet of the second evaporator 6, which can save compressor power consumption. At the same time, the ejection effect of the first ejector 29 can increase the operating pressure on the refrigerant side of the second evaporator 6, increase the heat exchange temperature difference between the waste heat of the low-temperature heat source medium and CO2 to enhance the heat absorption capacity, and also maintain the stability of the evaporator outlet pressure, solving the problem of sudden pressure drop in low-temperature CO2 evaporation and avoiding compressor surge. In addition, using the first ejector 29 to replace the mechanical compressor can reduce rotating parts, eliminate failure points such as motors and bearings, reduce maintenance costs, and is more resistant to high-pressure fluctuations in the supercritical CO2 cycle. Finally, the working fluid of the first ejector 29 originates from the preheated CO2 in the first intermediate heat exchanger 2. The energy recovered by its expansion can improve the CO2 grade in the path of the second evaporator 6, achieving a dual synergy of cascade heating and cascade compression, and further amplifying the energy efficiency benefits of the original design for utilizing geothermal water with a large temperature difference.

[0061] Specific Implementation Plan Three: Combining Figure 3 As shown, this invention provides a water-vapor cogeneration heat pump system with large temperature difference cascade heat extraction and heating, including a first evaporator 1, a second evaporator 6, a third condenser 16, a fourth expansion valve 17, a fifth expansion valve 18, a sixth compressor 19, a second intermediate heat exchanger 20, a seventh compressor 21, an eighth compressor 22, a fourth condenser 23, a third flow regulating valve 24, a fourth flow regulating valve 25, and a ninth compressor 26.

[0062] The inlet of the first evaporator 1 is connected to the heat source medium input pipeline 101. The outlet of the first evaporator 1 is connected to the inlet of the second evaporator 6 via the heat source medium transmission pipeline 102. The outlet of the second evaporator 6 outputs the medium via the heat source medium output pipeline 103.

[0063] The refrigerant outlet of the third condenser 16 is connected to the fourth expansion valve 17 via the twenty-eighth pipe 204 and the twenty-ninth pipe 205. The outlet of the fourth expansion valve 17 is connected to the refrigerant inlet of the first evaporator 1 via the thirtieth pipe 206. The refrigerant outlet of the first evaporator 1 is connected to the inlet of the seventh compressor 21 via the thirty-first pipe 207 and the thirty-seventh pipe 213.

[0064] The refrigerant outlet of the third condenser 16 is connected to the inlet of the fifth expansion valve 18 via the twenty-eighth pipe 204 and the thirty-second pipe 208. The outlet of the fifth expansion valve 18 is connected to the refrigerant inlet of the second evaporator 6 via the thirty-third pipe 209. The refrigerant outlet of the second evaporator 6 is connected to the inlet of the sixth compressor 19 via the thirty-fourth pipe 210. The outlet of the sixth compressor 19 is connected to the low-temperature side refrigerant inlet of the second intermediate heat exchanger 20 via the thirty-fifth pipe 211. The low-temperature side refrigerant outlet of the second intermediate heat exchanger 20 is connected to the inlet of the seventh compressor 21 via the thirty-sixth pipe 212 and the thirty-first pipe 207, and then via the thirty-seventh pipe 213. The outlet of the seventh compressor 21 is connected to the refrigerant inlet of the third condenser 16 via the thirty-eighth pipe 214.

[0065] The refrigerant outlet on the high-temperature side of the second intermediate heat exchanger 20 is connected to the inlet of the eighth compressor 22 via the thirty-ninth pipe 215. The outlet of the eighth compressor 22 is connected to the refrigerant inlet of the fourth condenser 23 via the fortieth pipe 216. The refrigerant outlet of the fourth condenser 23 is connected to the refrigerant inlet on the high-temperature side of the second intermediate heat exchanger 20 via the forty-first pipe 217.

[0066] The heated medium is connected to the inlet of the third condenser 16 via pipe 42, 218. The outlet of the third condenser 16 is connected to the inlet of the third flow regulating valve 24 via pipes 43, 219, and 44, 220. The outlet of the third flow regulating valve 24 outputs the medium via pipe 45, 221.

[0067] The heated medium is connected to the heated medium inlet of the third condenser 16 via the forty-second pipe 218. The heated medium outlet of the third condenser 16 is connected to the inlet of the fourth flow regulating valve 25 via the forty-third pipe 219 and the forty-sixth pipe 222. The outlet of the fourth flow regulating valve 25 is connected to the heated medium inlet of the fourth condenser 23 via the forty-seventh pipe 223. The heated medium outlet of the fourth condenser 23 is connected to the inlet of the ninth compressor 26 via the forty-eighth pipe 224. The outlet of the ninth compressor 26 outputs the medium via the forty-ninth pipe 225.

[0068] The operating principle of this implementation plan is as follows:

[0069] The high-temperature heat source medium enters the first evaporator 1 through the heat source medium input pipe 101 to release heat and cool down. It then flows into the second evaporator 6 through the heat source medium transmission pipe 102 to absorb heat again. Finally, the low-temperature heat source medium is discharged through the heat source medium output pipe 103.

[0070] The high-pressure CO2 liquid in the third condenser 16 is split. The main stream, after being throttled and depressurized by the fourth expansion valve 17, enters the first evaporator 1 for evaporation and heat absorption. The auxiliary stream, after being throttled and depressurized by the fifth expansion valve 18, enters the second evaporator 6 for evaporation and heat absorption. The low-temperature CO2 at the outlet of the second evaporator 6 is primary compressed by the sixth compressor 19 and enters the low-temperature side of the second intermediate heat exchanger 20. The medium-temperature CO2 at the outlet of the first evaporator 1 merges with the CO2 from the second intermediate heat exchanger 20 and enters the seventh compressor 21 for deep compression, releasing sensible heat in the third condenser 16.

[0071] The second intermediate heat exchanger 20 absorbs the waste heat of CO2 on the high-temperature side, causing a certain refrigerant to evaporate and enter the eighth compressor 22. After compression, the high-temperature refrigerant enters the fourth condenser 23 through the fortieth pipe 216 to release latent heat, and the condensate returns through the forty-first pipe 217.

[0072] After entering through the 42nd pipe 218, the cold water absorbs heat and is heated in the 3rd condenser 16, and then outputs 90°C hot water through the 43rd pipe 219, the 3rd flow regulating valve 24, and the 45th pipe 221. Another branch of cold water is preheated in the 3rd condenser 16, evaporates in the 4th condenser 23, and then pressurized by the 9th compressor 26 before being output through the 49th pipe 225.

[0073] The implementation method of this plan is as follows:

[0074] The high-temperature heat source medium in the inlet heat source medium input pipeline 101 is 50°C. It is cooled to 35°C by the first evaporator 1, and then cooled to 20°C by the second evaporator 6 before being output.

[0075] In the high-temperature section, the refrigerant CO2 evaporates at a temperature of 35°C and a pressure of 4.8 MPa, which is the supercritical state.

[0076] In the low-temperature section, the refrigerant CO2 evaporates at 15℃ and 4.5 MPa, which is the supercritical state. It is then compressed to 60℃ and 5.8 MPa by the sixth compressor (19).

[0077] The refrigerant R245fa evaporates at 65°C, driven by the second intermediate heat exchanger 20 at a pressure of 0.58 MPa. It is then compressed to 100°C and 1.8 MPa by the eighth compressor 22.

[0078] The CO2 mixture from the two branches is pressurized to 100℃ and 12.0MPa by the seventh compressor 21. The third condenser 16 releases sensible heat to produce 90℃ hot water. The fourth condenser 23 releases latent heat to transform the preheated water into 90℃ saturated steam, which is then pressurized and heated to 120℃ superheated steam by the ninth compressor 26.

[0079] The ratio of steam to water is controlled by a flow regulating valve. When the steam to hot water ratio is 1:1.5 (mass ratio), the system's coefficient of performance (COP) is not less than 2.5.

[0080] Overall, the system achieves three key effects. First, it enables deep, tiered heat extraction. Through a forced heat transfer path using series evaporators, heat energy is released progressively from high to low grade, breaking through the energy extraction limits of single-stage evaporation systems. Second, it achieves simultaneous generation of water and vapor phases. Based on a decoupled transfer mechanism of sensible and latent heat, the system simultaneously outputs liquid hot water and gaseous steam, meeting diverse industrial energy needs. Finally, the system achieves dynamic adaptive energy distribution. Its unique dual-expansion valve branch control structure adjusts the refrigerant flow rate to match changes in heat source grade in real time.

[0081] This invention integrates heating and a dual-path expansion and compression architecture for CO2 via a condenser. While maintaining the core advantages of utilizing large temperature differences in the heat source medium and co-producing water and steam, it achieves system compactness and energy consumption optimization, especially enhancing the dynamic adaptability of the low-temperature geothermal section. Specifically, the single CO2 cycle simplifies the heat source design and enhances system stability; the integration of preheating in the condenser and heat recovery from the compressor significantly reduces steam generation energy consumption. Compared to the first specific implementation scheme, this system is more suitable for regional integrated energy stations with large heat source fluctuations (such as shallow to medium-depth geothermal tailwater) and frequent adjustments to the steam / hot water ratio. It also offers higher tailwater extraction efficiency below 30°C, and the dual expansion valve control structure can respond to heat source changes within 10 seconds.

[0082] Specific Implementation Plan Four: Combining Figure 4 As shown, unlike specific implementation scheme three, a tenth compressor 27 is added. The inlet of the tenth compressor 27 is connected to the refrigerant outlet of the first evaporator 1 via the fiftieth pipe 226. The outlet of the tenth compressor 27 is connected to the inlet of the seventh compressor 21 via the confluence of the fifty-first pipe 227 and the thirty-sixth pipe 212 and the thirty-seventh pipe 213. By adding the tenth compressor 27, high and low pressure airflows are separated and compressed, and the CO2 gas at the outlet of the first evaporator 1 is pressurized separately, significantly reducing the pressure difference at the inlet of the seventh compressor 21 and reducing the main compressor power consumption. At the same time, it avoids the thermal imbalance caused by direct mixing of high / low temperature CO2 airflows, eliminates the risk of main compressor surge, and improves system stability. In addition, the temperature of the high-temperature CO2 is increased after pre-compression, and it is preheated together with the airflow at the outlet of the sixth compressor 19, which increases the heat exchange capacity on the low-temperature side of the second intermediate heat exchanger 20, further strengthening the driving force of refrigerant vapor circulation.

[0083] Specific Implementation Plan Five: Combining Figure 5 As shown, unlike specific implementation scheme three, a second ejector 28 is added. The working fluid inlet of the second ejector 28 is connected to the refrigerant outlet on the low-temperature side of the second intermediate heat exchanger 20 via the 52nd pipe 228, the ejector fluid inlet is connected to the refrigerant outlet of the first evaporator 1 via the 53rd pipe 229, and the mixed fluid outlet is connected to the inlet of the seventh compressor 21 via the 54th pipe 230. The second ejector 28 achieves a dual breakthrough in energy recovery and airflow optimization. Utilizing the expansion kinetic energy of the medium-temperature, medium-pressure CO2 at the low-temperature side outlet of the second intermediate heat exchanger 20, it ejects the low-temperature, low-pressure CO2 from the outlet of the first evaporator 1, mixes and pressurizes it, and then delivers it to the inlet of the eighth compressor 22. This optimization achieves three effects: first, it directly recovers the expansion work of the medium-pressure CO2 to replace mechanical compression, reducing the power consumption of the main compressor; second, it eliminates the thermodynamic losses from mixing airflows at different temperatures, improving compression efficiency; and third, it maintains a stable inlet temperature for the main compressor, completely eliminating the surge risk caused by geothermal water temperature fluctuations. This design achieves both energy saving and disturbance rejection improvements with zero moving parts, significantly reducing maintenance costs compared to the compressor scheme.

[0084] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A water vapor heat pump system for simultaneous heat extraction and heating in a large temperature difference stepped stage, characterized in that: It includes a first evaporator (1), a first intermediate heat exchanger (2), a first compressor (3), a first condenser (4), a first expansion valve (5), a second evaporator (6), a second compressor (7), a second expansion valve (8), a third compressor (9), a fourth compressor (10), a second condenser (11), a third expansion valve (12), a first flow regulating valve (13), a second flow regulating valve (14), and a fifth compressor (15). The first evaporator (1) is provided with a heat source medium inlet, and the heat source medium outlet of the first evaporator (1) is connected to the heat source medium inlet of the second evaporator (6). The second evaporator (6) is provided with a heat source medium outlet for discharging the medium. The refrigerant outlet on the low-temperature side of the first intermediate heat exchanger (2) is connected to the inlet of the first compressor (3). The outlet of the first compressor (3) is connected to the refrigerant inlet of the first condenser (4). One branch of the refrigerant outlet of the first condenser (4) is connected to the inlet of the first expansion valve (5). The outlet of the first expansion valve (5) is connected to the refrigerant inlet of the second evaporator (6). The refrigerant outlet of the second evaporator (6) is connected to the inlet of the second compressor (7). The outlet of the second compressor (7) merges with another branch of the refrigerant outlet on the low-temperature side of the first intermediate heat exchanger (2). The other branch of the refrigerant outlet of the first condenser (4) is connected to the inlet of the second expansion valve (8). The outlet of the second expansion valve (8) is connected to the refrigerant inlet of the first evaporator (1). The refrigerant outlet of the first evaporator (1) is connected to the inlet of the third compressor (9). The outlet of the third compressor (9) is connected to the low-temperature side refrigerant inlet of the first intermediate heat exchanger (2). The high-temperature side refrigerant outlet of the first intermediate heat exchanger (2) is connected to the inlet of the fourth compressor (10). The outlet of the fourth compressor (10) is connected to the refrigerant inlet of the second condenser (11). The second condenser (11) is connected to the inlet of the third expansion valve (12). The outlet of the third expansion valve (12) is connected to the high-temperature side refrigerant inlet of the first intermediate heat exchanger (2). The first condenser (4) is provided with a heating medium inlet, and a branch of the heating medium outlet of the first condenser (4) is connected to the inlet of the first flow regulating valve (13). The first flow regulating valve (13) is provided with a heating medium outlet for discharging the medium. Another branch of the outlet of the heated medium of the first condenser (4) is connected to the inlet of the second flow regulating valve (14). The outlet of the second flow regulating valve (14) is connected to the inlet of the heated medium of the second condenser (11). The outlet of the heated medium of the second condenser (11) is connected to the inlet of the fifth compressor (15). The fifth compressor (15) has an outlet for outputting the medium.

2. A water vapor heat pump system for simultaneous heat extraction and heating in a large temperature difference stepped stage, characterized in that: It includes a first evaporator (1), a first intermediate heat exchanger (2), a first compressor (3), a first condenser (4), a first expansion valve (5), a second evaporator (6), a second expansion valve (8), a third compressor (9), a fourth compressor (10), a second condenser (11), a third expansion valve (12), a first flow regulating valve (13), a second flow regulating valve (14), a fifth compressor (15), and a first ejector (29). The first evaporator (1) is provided with a heat source medium inlet, and the heat source medium outlet of the first evaporator (1) is connected to the heat source medium inlet of the second evaporator (6). The second evaporator (6) is provided with a heat source medium outlet for discharging the medium. The refrigerant outlet on the low-temperature side of the first intermediate heat exchanger (2) is connected to the working fluid inlet of the first ejector (29), and the refrigerant outlet of the second evaporator (6) is connected to the ejector fluid inlet of the first ejector (29). After the two branches are mixed, the mixed fluid outlet of the first ejector (29) is connected to the inlet of the first compressor (3), the outlet of the first compressor (3) is connected to the refrigerant inlet of the first condenser (4), one branch of the refrigerant outlet of the first condenser (4) is connected to the inlet of the first expansion valve (5), and the outlet of the first expansion valve (5) is connected to the refrigerant inlet of the second evaporator (6). The other branch of the refrigerant outlet of the first condenser (4) is connected to the inlet of the second expansion valve (8). The outlet of the second expansion valve (8) is connected to the refrigerant inlet of the first evaporator (1). The refrigerant outlet of the first evaporator (1) is connected to the inlet of the third compressor (9). The outlet of the third compressor (9) is connected to the low-temperature side refrigerant inlet of the first intermediate heat exchanger (2). The high-temperature side refrigerant outlet of the first intermediate heat exchanger (2) is connected to the inlet of the fourth compressor (10). The outlet of the fourth compressor (10) is connected to the refrigerant inlet of the second condenser (11). The second condenser (11) is connected to the inlet of the third expansion valve (12). The outlet of the third expansion valve (12) is connected to the high-temperature side refrigerant inlet of the first intermediate heat exchanger (2). The first condenser (4) is provided with a heating medium inlet, and a branch of the heating medium outlet of the first condenser (4) is connected to the inlet of the first flow regulating valve (13). The first flow regulating valve (13) is provided with a heating medium outlet for discharging the medium. Another branch of the outlet of the heated medium of the first condenser (4) is connected to the inlet of the second flow regulating valve (14). The outlet of the second flow regulating valve (14) is connected to the inlet of the heated medium of the second condenser (11). The outlet of the heated medium of the second condenser (11) is connected to the inlet of the fifth compressor (15). The fifth compressor (15) has an outlet for outputting the medium.

3. A water vapor heat pump system for simultaneous heat extraction and heating in a large temperature difference stepped stage, characterized in that: It includes a first evaporator (1), a second evaporator (6), a third condenser (16), a fourth expansion valve (17), a fifth expansion valve (18), a sixth compressor (19), a second intermediate heat exchanger (20), a seventh compressor (21), an eighth compressor (22), a fourth condenser (23), a third flow regulating valve (24), a fourth flow regulating valve (25), and a ninth compressor (26). The first evaporator (1) is provided with a heat source medium inlet, and the heat source medium outlet of the first evaporator (1) is connected to the heat source medium inlet of the second evaporator (6). The second evaporator (6) is provided with a heat source medium outlet for discharging the medium. A branch of the refrigerant outlet of the third condenser (16) is connected to the fourth expansion valve (17), the outlet of the fourth expansion valve (17) is connected to the refrigerant inlet of the first evaporator (1), and the refrigerant outlet of the first evaporator (1) is connected to the inlet of the seventh compressor (21). Another branch of the refrigerant outlet of the third condenser (16) is connected to the inlet of the fifth expansion valve (18). The outlet of the fifth expansion valve (18) is connected to the refrigerant inlet of the second evaporator (6). The refrigerant outlet of the second evaporator (6) is connected to the inlet of the sixth compressor (19). The outlet of the sixth compressor (19) is connected to the low-temperature side refrigerant inlet of the second intermediate heat exchanger (20). The low-temperature side refrigerant outlet of the second intermediate heat exchanger (20) merges with the refrigerant outlet of the first evaporator (1) and then connects to the inlet of the seventh compressor (21). The outlet of the seventh compressor (21) is connected to the refrigerant inlet of the third condenser (16). The refrigerant outlet on the high-temperature side of the second intermediate heat exchanger (20) is connected to the inlet of the eighth compressor (22), the outlet of the eighth compressor (22) is connected to the refrigerant inlet of the fourth condenser (23), and the refrigerant outlet of the fourth condenser (23) is connected to the refrigerant inlet on the high-temperature side of the second intermediate heat exchanger (20). The third condenser (16) is provided with a heated medium inlet, and a branch of the heated medium outlet of the third condenser (16) is connected to the inlet of the third flow regulating valve (24). The third flow regulating valve (24) is provided with a heated medium outlet for discharging the medium. Another branch of the outlet of the heated medium of the third condenser (16) is connected to the inlet of the fourth flow regulating valve (25). The outlet of the fourth flow regulating valve (25) is connected to the inlet of the heated medium of the fourth condenser (23). The outlet of the heated medium of the fourth condenser (23) is connected to the inlet of the ninth compressor (26). The ninth compressor (26) is provided with an outlet for the heated medium for outputting the medium.

4. The water vapor co-generation heat pump system with large temperature difference cascade heat extraction and heating according to claim 3, characterized in that: It also includes the tenth compressor (27). The refrigerant outlet of the first evaporator (1) is connected to the inlet of the tenth compressor (27). The outlet of the tenth compressor (27) merges with the refrigerant outlet on the low-temperature side of the second intermediate heat exchanger (20) and is then connected to the inlet of the seventh compressor (21).

5. A water-vapor co-generation heat pump system with large temperature difference cascade heat extraction and heating according to claim 3, characterized in that, It also includes a second injector (28). The working fluid inlet of the second ejector (28) is connected to the refrigerant outlet on the low-temperature side of the second intermediate heat exchanger (20), and the ejector fluid inlet of the second ejector (28) is connected to the refrigerant outlet of the first evaporator (1). After the two pipelines merge, the mixed fluid outlet of the second ejector (28) is connected to the inlet of the seventh compressor (21).

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